1 /* 2 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 // no precompiled headers 26 #include "classfile/classLoader.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "classfile/vmSymbols.hpp" 29 #include "code/icBuffer.hpp" 30 #include "code/vtableStubs.hpp" 31 #include "compiler/compileBroker.hpp" 32 #include "compiler/disassembler.hpp" 33 #include "interpreter/interpreter.hpp" 34 #include "jvm_linux.h" 35 #include "memory/allocation.inline.hpp" 36 #include "memory/filemap.hpp" 37 #include "mutex_linux.inline.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "os_share_linux.hpp" 40 #include "prims/jniFastGetField.hpp" 41 #include "prims/jvm.h" 42 #include "prims/jvm_misc.hpp" 43 #include "runtime/arguments.hpp" 44 #include "runtime/extendedPC.hpp" 45 #include "runtime/globals.hpp" 46 #include "runtime/interfaceSupport.hpp" 47 #include "runtime/init.hpp" 48 #include "runtime/java.hpp" 49 #include "runtime/javaCalls.hpp" 50 #include "runtime/mutexLocker.hpp" 51 #include "runtime/objectMonitor.hpp" 52 #include "runtime/osThread.hpp" 53 #include "runtime/perfMemory.hpp" 54 #include "runtime/sharedRuntime.hpp" 55 #include "runtime/statSampler.hpp" 56 #include "runtime/stubRoutines.hpp" 57 #include "runtime/thread.inline.hpp" 58 #include "runtime/threadCritical.hpp" 59 #include "runtime/timer.hpp" 60 #include "services/attachListener.hpp" 61 #include "services/memTracker.hpp" 62 #include "services/runtimeService.hpp" 63 #include "utilities/decoder.hpp" 64 #include "utilities/defaultStream.hpp" 65 #include "utilities/events.hpp" 66 #include "utilities/elfFile.hpp" 67 #include "utilities/growableArray.hpp" 68 #include "utilities/vmError.hpp" 69 70 // put OS-includes here 71 # include <sys/types.h> 72 # include <sys/mman.h> 73 # include <sys/stat.h> 74 # include <sys/select.h> 75 # include <pthread.h> 76 # include <signal.h> 77 # include <errno.h> 78 # include <dlfcn.h> 79 # include <stdio.h> 80 # include <unistd.h> 81 # include <sys/resource.h> 82 # include <pthread.h> 83 # include <sys/stat.h> 84 # include <sys/time.h> 85 # include <sys/times.h> 86 # include <sys/utsname.h> 87 # include <sys/socket.h> 88 # include <sys/wait.h> 89 # include <pwd.h> 90 # include <poll.h> 91 # include <semaphore.h> 92 # include <fcntl.h> 93 # include <string.h> 94 # include <syscall.h> 95 # include <sys/sysinfo.h> 96 # include <gnu/libc-version.h> 97 # include <sys/ipc.h> 98 # include <sys/shm.h> 99 # include <link.h> 100 # include <stdint.h> 101 # include <inttypes.h> 102 # include <sys/ioctl.h> 103 104 #define MAX_PATH (2 * K) 105 106 // for timer info max values which include all bits 107 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 108 109 #define LARGEPAGES_BIT (1 << 6) 110 //////////////////////////////////////////////////////////////////////////////// 111 // global variables 112 julong os::Linux::_physical_memory = 0; 113 114 address os::Linux::_initial_thread_stack_bottom = NULL; 115 uintptr_t os::Linux::_initial_thread_stack_size = 0; 116 117 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 118 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 119 Mutex* os::Linux::_createThread_lock = NULL; 120 pthread_t os::Linux::_main_thread; 121 int os::Linux::_page_size = -1; 122 const int os::Linux::_vm_default_page_size = (8 * K); 123 bool os::Linux::_is_floating_stack = false; 124 bool os::Linux::_is_NPTL = false; 125 bool os::Linux::_supports_fast_thread_cpu_time = false; 126 const char * os::Linux::_glibc_version = NULL; 127 const char * os::Linux::_libpthread_version = NULL; 128 129 static jlong initial_time_count=0; 130 131 static int clock_tics_per_sec = 100; 132 133 // For diagnostics to print a message once. see run_periodic_checks 134 static sigset_t check_signal_done; 135 static bool check_signals = true;; 136 137 static pid_t _initial_pid = 0; 138 139 /* Signal number used to suspend/resume a thread */ 140 141 /* do not use any signal number less than SIGSEGV, see 4355769 */ 142 static int SR_signum = SIGUSR2; 143 sigset_t SR_sigset; 144 145 /* Used to protect dlsym() calls */ 146 static pthread_mutex_t dl_mutex; 147 148 // Declarations 149 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time); 150 151 #ifdef JAVASE_EMBEDDED 152 class MemNotifyThread: public Thread { 153 friend class VMStructs; 154 public: 155 virtual void run(); 156 157 private: 158 static MemNotifyThread* _memnotify_thread; 159 int _fd; 160 161 public: 162 163 // Constructor 164 MemNotifyThread(int fd); 165 166 // Tester 167 bool is_memnotify_thread() const { return true; } 168 169 // Printing 170 char* name() const { return (char*)"Linux MemNotify Thread"; } 171 172 // Returns the single instance of the MemNotifyThread 173 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; } 174 175 // Create and start the single instance of MemNotifyThread 176 static void start(); 177 }; 178 #endif // JAVASE_EMBEDDED 179 180 // utility functions 181 182 static int SR_initialize(); 183 184 julong os::available_memory() { 185 return Linux::available_memory(); 186 } 187 188 julong os::Linux::available_memory() { 189 // values in struct sysinfo are "unsigned long" 190 struct sysinfo si; 191 sysinfo(&si); 192 193 return (julong)si.freeram * si.mem_unit; 194 } 195 196 julong os::physical_memory() { 197 return Linux::physical_memory(); 198 } 199 200 //////////////////////////////////////////////////////////////////////////////// 201 // environment support 202 203 bool os::getenv(const char* name, char* buf, int len) { 204 const char* val = ::getenv(name); 205 if (val != NULL && strlen(val) < (size_t)len) { 206 strcpy(buf, val); 207 return true; 208 } 209 if (len > 0) buf[0] = 0; // return a null string 210 return false; 211 } 212 213 214 // Return true if user is running as root. 215 216 bool os::have_special_privileges() { 217 static bool init = false; 218 static bool privileges = false; 219 if (!init) { 220 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 221 init = true; 222 } 223 return privileges; 224 } 225 226 227 #ifndef SYS_gettid 228 // i386: 224, ia64: 1105, amd64: 186, sparc 143 229 #ifdef __ia64__ 230 #define SYS_gettid 1105 231 #elif __i386__ 232 #define SYS_gettid 224 233 #elif __amd64__ 234 #define SYS_gettid 186 235 #elif __sparc__ 236 #define SYS_gettid 143 237 #else 238 #error define gettid for the arch 239 #endif 240 #endif 241 242 // Cpu architecture string 243 #if defined(ZERO) 244 static char cpu_arch[] = ZERO_LIBARCH; 245 #elif defined(IA64) 246 static char cpu_arch[] = "ia64"; 247 #elif defined(IA32) 248 static char cpu_arch[] = "i386"; 249 #elif defined(AMD64) 250 static char cpu_arch[] = "amd64"; 251 #elif defined(ARM) 252 static char cpu_arch[] = "arm"; 253 #elif defined(PPC) 254 static char cpu_arch[] = "ppc"; 255 #elif defined(SPARC) 256 # ifdef _LP64 257 static char cpu_arch[] = "sparcv9"; 258 # else 259 static char cpu_arch[] = "sparc"; 260 # endif 261 #else 262 #error Add appropriate cpu_arch setting 263 #endif 264 265 266 // pid_t gettid() 267 // 268 // Returns the kernel thread id of the currently running thread. Kernel 269 // thread id is used to access /proc. 270 // 271 // (Note that getpid() on LinuxThreads returns kernel thread id too; but 272 // on NPTL, it returns the same pid for all threads, as required by POSIX.) 273 // 274 pid_t os::Linux::gettid() { 275 int rslt = syscall(SYS_gettid); 276 if (rslt == -1) { 277 // old kernel, no NPTL support 278 return getpid(); 279 } else { 280 return (pid_t)rslt; 281 } 282 } 283 284 // Most versions of linux have a bug where the number of processors are 285 // determined by looking at the /proc file system. In a chroot environment, 286 // the system call returns 1. This causes the VM to act as if it is 287 // a single processor and elide locking (see is_MP() call). 288 static bool unsafe_chroot_detected = false; 289 static const char *unstable_chroot_error = "/proc file system not found.\n" 290 "Java may be unstable running multithreaded in a chroot " 291 "environment on Linux when /proc filesystem is not mounted."; 292 293 void os::Linux::initialize_system_info() { 294 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 295 if (processor_count() == 1) { 296 pid_t pid = os::Linux::gettid(); 297 char fname[32]; 298 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 299 FILE *fp = fopen(fname, "r"); 300 if (fp == NULL) { 301 unsafe_chroot_detected = true; 302 } else { 303 fclose(fp); 304 } 305 } 306 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 307 assert(processor_count() > 0, "linux error"); 308 } 309 310 void os::init_system_properties_values() { 311 // char arch[12]; 312 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch)); 313 314 // The next steps are taken in the product version: 315 // 316 // Obtain the JAVA_HOME value from the location of libjvm.so. 317 // This library should be located at: 318 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so. 319 // 320 // If "/jre/lib/" appears at the right place in the path, then we 321 // assume libjvm.so is installed in a JDK and we use this path. 322 // 323 // Otherwise exit with message: "Could not create the Java virtual machine." 324 // 325 // The following extra steps are taken in the debugging version: 326 // 327 // If "/jre/lib/" does NOT appear at the right place in the path 328 // instead of exit check for $JAVA_HOME environment variable. 329 // 330 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 331 // then we append a fake suffix "hotspot/libjvm.so" to this path so 332 // it looks like libjvm.so is installed there 333 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 334 // 335 // Otherwise exit. 336 // 337 // Important note: if the location of libjvm.so changes this 338 // code needs to be changed accordingly. 339 340 // The next few definitions allow the code to be verbatim: 341 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n), mtInternal) 342 #define getenv(n) ::getenv(n) 343 344 /* 345 * See ld(1): 346 * The linker uses the following search paths to locate required 347 * shared libraries: 348 * 1: ... 349 * ... 350 * 7: The default directories, normally /lib and /usr/lib. 351 */ 352 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 353 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 354 #else 355 #define DEFAULT_LIBPATH "/lib:/usr/lib" 356 #endif 357 358 #define EXTENSIONS_DIR "/lib/ext" 359 #define ENDORSED_DIR "/lib/endorsed" 360 #define REG_DIR "/usr/java/packages" 361 362 { 363 /* sysclasspath, java_home, dll_dir */ 364 { 365 char *home_path; 366 char *dll_path; 367 char *pslash; 368 char buf[MAXPATHLEN]; 369 os::jvm_path(buf, sizeof(buf)); 370 371 // Found the full path to libjvm.so. 372 // Now cut the path to <java_home>/jre if we can. 373 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */ 374 pslash = strrchr(buf, '/'); 375 if (pslash != NULL) 376 *pslash = '\0'; /* get rid of /{client|server|hotspot} */ 377 dll_path = malloc(strlen(buf) + 1); 378 if (dll_path == NULL) 379 return; 380 strcpy(dll_path, buf); 381 Arguments::set_dll_dir(dll_path); 382 383 if (pslash != NULL) { 384 pslash = strrchr(buf, '/'); 385 if (pslash != NULL) { 386 *pslash = '\0'; /* get rid of /<arch> */ 387 pslash = strrchr(buf, '/'); 388 if (pslash != NULL) 389 *pslash = '\0'; /* get rid of /lib */ 390 } 391 } 392 393 home_path = malloc(strlen(buf) + 1); 394 if (home_path == NULL) 395 return; 396 strcpy(home_path, buf); 397 Arguments::set_java_home(home_path); 398 399 if (!set_boot_path('/', ':')) 400 return; 401 } 402 403 /* 404 * Where to look for native libraries 405 * 406 * Note: Due to a legacy implementation, most of the library path 407 * is set in the launcher. This was to accomodate linking restrictions 408 * on legacy Linux implementations (which are no longer supported). 409 * Eventually, all the library path setting will be done here. 410 * 411 * However, to prevent the proliferation of improperly built native 412 * libraries, the new path component /usr/java/packages is added here. 413 * Eventually, all the library path setting will be done here. 414 */ 415 { 416 char *ld_library_path; 417 418 /* 419 * Construct the invariant part of ld_library_path. Note that the 420 * space for the colon and the trailing null are provided by the 421 * nulls included by the sizeof operator (so actually we allocate 422 * a byte more than necessary). 423 */ 424 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") + 425 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH)); 426 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch); 427 428 /* 429 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It 430 * should always exist (until the legacy problem cited above is 431 * addressed). 432 */ 433 char *v = getenv("LD_LIBRARY_PATH"); 434 if (v != NULL) { 435 char *t = ld_library_path; 436 /* That's +1 for the colon and +1 for the trailing '\0' */ 437 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1); 438 sprintf(ld_library_path, "%s:%s", v, t); 439 } 440 Arguments::set_library_path(ld_library_path); 441 } 442 443 /* 444 * Extensions directories. 445 * 446 * Note that the space for the colon and the trailing null are provided 447 * by the nulls included by the sizeof operator (so actually one byte more 448 * than necessary is allocated). 449 */ 450 { 451 char *buf = malloc(strlen(Arguments::get_java_home()) + 452 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR)); 453 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR, 454 Arguments::get_java_home()); 455 Arguments::set_ext_dirs(buf); 456 } 457 458 /* Endorsed standards default directory. */ 459 { 460 char * buf; 461 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR)); 462 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home()); 463 Arguments::set_endorsed_dirs(buf); 464 } 465 } 466 467 #undef malloc 468 #undef getenv 469 #undef EXTENSIONS_DIR 470 #undef ENDORSED_DIR 471 472 // Done 473 return; 474 } 475 476 //////////////////////////////////////////////////////////////////////////////// 477 // breakpoint support 478 479 void os::breakpoint() { 480 BREAKPOINT; 481 } 482 483 extern "C" void breakpoint() { 484 // use debugger to set breakpoint here 485 } 486 487 //////////////////////////////////////////////////////////////////////////////// 488 // signal support 489 490 debug_only(static bool signal_sets_initialized = false); 491 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 492 493 bool os::Linux::is_sig_ignored(int sig) { 494 struct sigaction oact; 495 sigaction(sig, (struct sigaction*)NULL, &oact); 496 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 497 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 498 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) 499 return true; 500 else 501 return false; 502 } 503 504 void os::Linux::signal_sets_init() { 505 // Should also have an assertion stating we are still single-threaded. 506 assert(!signal_sets_initialized, "Already initialized"); 507 // Fill in signals that are necessarily unblocked for all threads in 508 // the VM. Currently, we unblock the following signals: 509 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 510 // by -Xrs (=ReduceSignalUsage)); 511 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 512 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 513 // the dispositions or masks wrt these signals. 514 // Programs embedding the VM that want to use the above signals for their 515 // own purposes must, at this time, use the "-Xrs" option to prevent 516 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 517 // (See bug 4345157, and other related bugs). 518 // In reality, though, unblocking these signals is really a nop, since 519 // these signals are not blocked by default. 520 sigemptyset(&unblocked_sigs); 521 sigemptyset(&allowdebug_blocked_sigs); 522 sigaddset(&unblocked_sigs, SIGILL); 523 sigaddset(&unblocked_sigs, SIGSEGV); 524 sigaddset(&unblocked_sigs, SIGBUS); 525 sigaddset(&unblocked_sigs, SIGFPE); 526 sigaddset(&unblocked_sigs, SR_signum); 527 528 if (!ReduceSignalUsage) { 529 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 530 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 531 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 532 } 533 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 534 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 535 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 536 } 537 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 538 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 539 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 540 } 541 } 542 // Fill in signals that are blocked by all but the VM thread. 543 sigemptyset(&vm_sigs); 544 if (!ReduceSignalUsage) 545 sigaddset(&vm_sigs, BREAK_SIGNAL); 546 debug_only(signal_sets_initialized = true); 547 548 } 549 550 // These are signals that are unblocked while a thread is running Java. 551 // (For some reason, they get blocked by default.) 552 sigset_t* os::Linux::unblocked_signals() { 553 assert(signal_sets_initialized, "Not initialized"); 554 return &unblocked_sigs; 555 } 556 557 // These are the signals that are blocked while a (non-VM) thread is 558 // running Java. Only the VM thread handles these signals. 559 sigset_t* os::Linux::vm_signals() { 560 assert(signal_sets_initialized, "Not initialized"); 561 return &vm_sigs; 562 } 563 564 // These are signals that are blocked during cond_wait to allow debugger in 565 sigset_t* os::Linux::allowdebug_blocked_signals() { 566 assert(signal_sets_initialized, "Not initialized"); 567 return &allowdebug_blocked_sigs; 568 } 569 570 void os::Linux::hotspot_sigmask(Thread* thread) { 571 572 //Save caller's signal mask before setting VM signal mask 573 sigset_t caller_sigmask; 574 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 575 576 OSThread* osthread = thread->osthread(); 577 osthread->set_caller_sigmask(caller_sigmask); 578 579 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 580 581 if (!ReduceSignalUsage) { 582 if (thread->is_VM_thread()) { 583 // Only the VM thread handles BREAK_SIGNAL ... 584 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 585 } else { 586 // ... all other threads block BREAK_SIGNAL 587 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 588 } 589 } 590 } 591 592 ////////////////////////////////////////////////////////////////////////////// 593 // detecting pthread library 594 595 void os::Linux::libpthread_init() { 596 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION 597 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a 598 // generic name for earlier versions. 599 // Define macros here so we can build HotSpot on old systems. 600 # ifndef _CS_GNU_LIBC_VERSION 601 # define _CS_GNU_LIBC_VERSION 2 602 # endif 603 # ifndef _CS_GNU_LIBPTHREAD_VERSION 604 # define _CS_GNU_LIBPTHREAD_VERSION 3 605 # endif 606 607 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 608 if (n > 0) { 609 char *str = (char *)malloc(n, mtInternal); 610 confstr(_CS_GNU_LIBC_VERSION, str, n); 611 os::Linux::set_glibc_version(str); 612 } else { 613 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version() 614 static char _gnu_libc_version[32]; 615 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version), 616 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release()); 617 os::Linux::set_glibc_version(_gnu_libc_version); 618 } 619 620 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 621 if (n > 0) { 622 char *str = (char *)malloc(n, mtInternal); 623 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 624 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells 625 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this 626 // is the case. LinuxThreads has a hard limit on max number of threads. 627 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value. 628 // On the other hand, NPTL does not have such a limit, sysconf() 629 // will return -1 and errno is not changed. Check if it is really NPTL. 630 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 && 631 strstr(str, "NPTL") && 632 sysconf(_SC_THREAD_THREADS_MAX) > 0) { 633 free(str); 634 os::Linux::set_libpthread_version("linuxthreads"); 635 } else { 636 os::Linux::set_libpthread_version(str); 637 } 638 } else { 639 // glibc before 2.3.2 only has LinuxThreads. 640 os::Linux::set_libpthread_version("linuxthreads"); 641 } 642 643 if (strstr(libpthread_version(), "NPTL")) { 644 os::Linux::set_is_NPTL(); 645 } else { 646 os::Linux::set_is_LinuxThreads(); 647 } 648 649 // LinuxThreads have two flavors: floating-stack mode, which allows variable 650 // stack size; and fixed-stack mode. NPTL is always floating-stack. 651 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) { 652 os::Linux::set_is_floating_stack(); 653 } 654 } 655 656 ///////////////////////////////////////////////////////////////////////////// 657 // thread stack 658 659 // Force Linux kernel to expand current thread stack. If "bottom" is close 660 // to the stack guard, caller should block all signals. 661 // 662 // MAP_GROWSDOWN: 663 // A special mmap() flag that is used to implement thread stacks. It tells 664 // kernel that the memory region should extend downwards when needed. This 665 // allows early versions of LinuxThreads to only mmap the first few pages 666 // when creating a new thread. Linux kernel will automatically expand thread 667 // stack as needed (on page faults). 668 // 669 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 670 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 671 // region, it's hard to tell if the fault is due to a legitimate stack 672 // access or because of reading/writing non-exist memory (e.g. buffer 673 // overrun). As a rule, if the fault happens below current stack pointer, 674 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 675 // application (see Linux kernel fault.c). 676 // 677 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 678 // stack overflow detection. 679 // 680 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 681 // not use this flag. However, the stack of initial thread is not created 682 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though 683 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack 684 // and then attach the thread to JVM. 685 // 686 // To get around the problem and allow stack banging on Linux, we need to 687 // manually expand thread stack after receiving the SIGSEGV. 688 // 689 // There are two ways to expand thread stack to address "bottom", we used 690 // both of them in JVM before 1.5: 691 // 1. adjust stack pointer first so that it is below "bottom", and then 692 // touch "bottom" 693 // 2. mmap() the page in question 694 // 695 // Now alternate signal stack is gone, it's harder to use 2. For instance, 696 // if current sp is already near the lower end of page 101, and we need to 697 // call mmap() to map page 100, it is possible that part of the mmap() frame 698 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 699 // That will destroy the mmap() frame and cause VM to crash. 700 // 701 // The following code works by adjusting sp first, then accessing the "bottom" 702 // page to force a page fault. Linux kernel will then automatically expand the 703 // stack mapping. 704 // 705 // _expand_stack_to() assumes its frame size is less than page size, which 706 // should always be true if the function is not inlined. 707 708 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 709 #define NOINLINE 710 #else 711 #define NOINLINE __attribute__ ((noinline)) 712 #endif 713 714 static void _expand_stack_to(address bottom) NOINLINE; 715 716 static void _expand_stack_to(address bottom) { 717 address sp; 718 size_t size; 719 volatile char *p; 720 721 // Adjust bottom to point to the largest address within the same page, it 722 // gives us a one-page buffer if alloca() allocates slightly more memory. 723 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 724 bottom += os::Linux::page_size() - 1; 725 726 // sp might be slightly above current stack pointer; if that's the case, we 727 // will alloca() a little more space than necessary, which is OK. Don't use 728 // os::current_stack_pointer(), as its result can be slightly below current 729 // stack pointer, causing us to not alloca enough to reach "bottom". 730 sp = (address)&sp; 731 732 if (sp > bottom) { 733 size = sp - bottom; 734 p = (volatile char *)alloca(size); 735 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 736 p[0] = '\0'; 737 } 738 } 739 740 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 741 assert(t!=NULL, "just checking"); 742 assert(t->osthread()->expanding_stack(), "expand should be set"); 743 assert(t->stack_base() != NULL, "stack_base was not initialized"); 744 745 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 746 sigset_t mask_all, old_sigset; 747 sigfillset(&mask_all); 748 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 749 _expand_stack_to(addr); 750 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 751 return true; 752 } 753 return false; 754 } 755 756 ////////////////////////////////////////////////////////////////////////////// 757 // create new thread 758 759 static address highest_vm_reserved_address(); 760 761 // check if it's safe to start a new thread 762 static bool _thread_safety_check(Thread* thread) { 763 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) { 764 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat) 765 // Heap is mmap'ed at lower end of memory space. Thread stacks are 766 // allocated (MAP_FIXED) from high address space. Every thread stack 767 // occupies a fixed size slot (usually 2Mbytes, but user can change 768 // it to other values if they rebuild LinuxThreads). 769 // 770 // Problem with MAP_FIXED is that mmap() can still succeed even part of 771 // the memory region has already been mmap'ed. That means if we have too 772 // many threads and/or very large heap, eventually thread stack will 773 // collide with heap. 774 // 775 // Here we try to prevent heap/stack collision by comparing current 776 // stack bottom with the highest address that has been mmap'ed by JVM 777 // plus a safety margin for memory maps created by native code. 778 // 779 // This feature can be disabled by setting ThreadSafetyMargin to 0 780 // 781 if (ThreadSafetyMargin > 0) { 782 address stack_bottom = os::current_stack_base() - os::current_stack_size(); 783 784 // not safe if our stack extends below the safety margin 785 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address(); 786 } else { 787 return true; 788 } 789 } else { 790 // Floating stack LinuxThreads or NPTL: 791 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When 792 // there's not enough space left, pthread_create() will fail. If we come 793 // here, that means enough space has been reserved for stack. 794 return true; 795 } 796 } 797 798 // Thread start routine for all newly created threads 799 static void *java_start(Thread *thread) { 800 // Try to randomize the cache line index of hot stack frames. 801 // This helps when threads of the same stack traces evict each other's 802 // cache lines. The threads can be either from the same JVM instance, or 803 // from different JVM instances. The benefit is especially true for 804 // processors with hyperthreading technology. 805 static int counter = 0; 806 int pid = os::current_process_id(); 807 alloca(((pid ^ counter++) & 7) * 128); 808 809 ThreadLocalStorage::set_thread(thread); 810 811 OSThread* osthread = thread->osthread(); 812 Monitor* sync = osthread->startThread_lock(); 813 814 // non floating stack LinuxThreads needs extra check, see above 815 if (!_thread_safety_check(thread)) { 816 // notify parent thread 817 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 818 osthread->set_state(ZOMBIE); 819 sync->notify_all(); 820 return NULL; 821 } 822 823 // thread_id is kernel thread id (similar to Solaris LWP id) 824 osthread->set_thread_id(os::Linux::gettid()); 825 826 if (UseNUMA) { 827 int lgrp_id = os::numa_get_group_id(); 828 if (lgrp_id != -1) { 829 thread->set_lgrp_id(lgrp_id); 830 } 831 } 832 // initialize signal mask for this thread 833 os::Linux::hotspot_sigmask(thread); 834 835 // initialize floating point control register 836 os::Linux::init_thread_fpu_state(); 837 838 // handshaking with parent thread 839 { 840 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 841 842 // notify parent thread 843 osthread->set_state(INITIALIZED); 844 sync->notify_all(); 845 846 // wait until os::start_thread() 847 while (osthread->get_state() == INITIALIZED) { 848 sync->wait(Mutex::_no_safepoint_check_flag); 849 } 850 } 851 852 // call one more level start routine 853 thread->run(); 854 855 return 0; 856 } 857 858 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) { 859 assert(thread->osthread() == NULL, "caller responsible"); 860 861 // Allocate the OSThread object 862 OSThread* osthread = new OSThread(NULL, NULL); 863 if (osthread == NULL) { 864 return false; 865 } 866 867 // set the correct thread state 868 osthread->set_thread_type(thr_type); 869 870 // Initial state is ALLOCATED but not INITIALIZED 871 osthread->set_state(ALLOCATED); 872 873 thread->set_osthread(osthread); 874 875 // init thread attributes 876 pthread_attr_t attr; 877 pthread_attr_init(&attr); 878 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 879 880 // stack size 881 if (os::Linux::supports_variable_stack_size()) { 882 // calculate stack size if it's not specified by caller 883 if (stack_size == 0) { 884 stack_size = os::Linux::default_stack_size(thr_type); 885 886 switch (thr_type) { 887 case os::java_thread: 888 // Java threads use ThreadStackSize which default value can be 889 // changed with the flag -Xss 890 assert (JavaThread::stack_size_at_create() > 0, "this should be set"); 891 stack_size = JavaThread::stack_size_at_create(); 892 break; 893 case os::compiler_thread: 894 if (CompilerThreadStackSize > 0) { 895 stack_size = (size_t)(CompilerThreadStackSize * K); 896 break; 897 } // else fall through: 898 // use VMThreadStackSize if CompilerThreadStackSize is not defined 899 case os::vm_thread: 900 case os::pgc_thread: 901 case os::cgc_thread: 902 case os::watcher_thread: 903 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 904 break; 905 } 906 } 907 908 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 909 pthread_attr_setstacksize(&attr, stack_size); 910 } else { 911 // let pthread_create() pick the default value. 912 } 913 914 // glibc guard page 915 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 916 917 ThreadState state; 918 919 { 920 // Serialize thread creation if we are running with fixed stack LinuxThreads 921 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack(); 922 if (lock) { 923 os::Linux::createThread_lock()->lock_without_safepoint_check(); 924 } 925 926 pthread_t tid; 927 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 928 929 pthread_attr_destroy(&attr); 930 931 if (ret != 0) { 932 if (PrintMiscellaneous && (Verbose || WizardMode)) { 933 perror("pthread_create()"); 934 } 935 // Need to clean up stuff we've allocated so far 936 thread->set_osthread(NULL); 937 delete osthread; 938 if (lock) os::Linux::createThread_lock()->unlock(); 939 return false; 940 } 941 942 // Store pthread info into the OSThread 943 osthread->set_pthread_id(tid); 944 945 // Wait until child thread is either initialized or aborted 946 { 947 Monitor* sync_with_child = osthread->startThread_lock(); 948 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 949 while ((state = osthread->get_state()) == ALLOCATED) { 950 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 951 } 952 } 953 954 if (lock) { 955 os::Linux::createThread_lock()->unlock(); 956 } 957 } 958 959 // Aborted due to thread limit being reached 960 if (state == ZOMBIE) { 961 thread->set_osthread(NULL); 962 delete osthread; 963 return false; 964 } 965 966 // The thread is returned suspended (in state INITIALIZED), 967 // and is started higher up in the call chain 968 assert(state == INITIALIZED, "race condition"); 969 return true; 970 } 971 972 ///////////////////////////////////////////////////////////////////////////// 973 // attach existing thread 974 975 // bootstrap the main thread 976 bool os::create_main_thread(JavaThread* thread) { 977 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 978 return create_attached_thread(thread); 979 } 980 981 bool os::create_attached_thread(JavaThread* thread) { 982 #ifdef ASSERT 983 thread->verify_not_published(); 984 #endif 985 986 // Allocate the OSThread object 987 OSThread* osthread = new OSThread(NULL, NULL); 988 989 if (osthread == NULL) { 990 return false; 991 } 992 993 // Store pthread info into the OSThread 994 osthread->set_thread_id(os::Linux::gettid()); 995 osthread->set_pthread_id(::pthread_self()); 996 997 // initialize floating point control register 998 os::Linux::init_thread_fpu_state(); 999 1000 // Initial thread state is RUNNABLE 1001 osthread->set_state(RUNNABLE); 1002 1003 thread->set_osthread(osthread); 1004 1005 if (UseNUMA) { 1006 int lgrp_id = os::numa_get_group_id(); 1007 if (lgrp_id != -1) { 1008 thread->set_lgrp_id(lgrp_id); 1009 } 1010 } 1011 1012 if (os::Linux::is_initial_thread()) { 1013 // If current thread is initial thread, its stack is mapped on demand, 1014 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 1015 // the entire stack region to avoid SEGV in stack banging. 1016 // It is also useful to get around the heap-stack-gap problem on SuSE 1017 // kernel (see 4821821 for details). We first expand stack to the top 1018 // of yellow zone, then enable stack yellow zone (order is significant, 1019 // enabling yellow zone first will crash JVM on SuSE Linux), so there 1020 // is no gap between the last two virtual memory regions. 1021 1022 JavaThread *jt = (JavaThread *)thread; 1023 address addr = jt->stack_yellow_zone_base(); 1024 assert(addr != NULL, "initialization problem?"); 1025 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 1026 1027 osthread->set_expanding_stack(); 1028 os::Linux::manually_expand_stack(jt, addr); 1029 osthread->clear_expanding_stack(); 1030 } 1031 1032 // initialize signal mask for this thread 1033 // and save the caller's signal mask 1034 os::Linux::hotspot_sigmask(thread); 1035 1036 return true; 1037 } 1038 1039 void os::pd_start_thread(Thread* thread) { 1040 OSThread * osthread = thread->osthread(); 1041 assert(osthread->get_state() != INITIALIZED, "just checking"); 1042 Monitor* sync_with_child = osthread->startThread_lock(); 1043 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 1044 sync_with_child->notify(); 1045 } 1046 1047 // Free Linux resources related to the OSThread 1048 void os::free_thread(OSThread* osthread) { 1049 assert(osthread != NULL, "osthread not set"); 1050 1051 if (Thread::current()->osthread() == osthread) { 1052 // Restore caller's signal mask 1053 sigset_t sigmask = osthread->caller_sigmask(); 1054 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1055 } 1056 1057 delete osthread; 1058 } 1059 1060 ////////////////////////////////////////////////////////////////////////////// 1061 // thread local storage 1062 1063 int os::allocate_thread_local_storage() { 1064 pthread_key_t key; 1065 int rslt = pthread_key_create(&key, NULL); 1066 assert(rslt == 0, "cannot allocate thread local storage"); 1067 return (int)key; 1068 } 1069 1070 // Note: This is currently not used by VM, as we don't destroy TLS key 1071 // on VM exit. 1072 void os::free_thread_local_storage(int index) { 1073 int rslt = pthread_key_delete((pthread_key_t)index); 1074 assert(rslt == 0, "invalid index"); 1075 } 1076 1077 void os::thread_local_storage_at_put(int index, void* value) { 1078 int rslt = pthread_setspecific((pthread_key_t)index, value); 1079 assert(rslt == 0, "pthread_setspecific failed"); 1080 } 1081 1082 extern "C" Thread* get_thread() { 1083 return ThreadLocalStorage::thread(); 1084 } 1085 1086 ////////////////////////////////////////////////////////////////////////////// 1087 // initial thread 1088 1089 // Check if current thread is the initial thread, similar to Solaris thr_main. 1090 bool os::Linux::is_initial_thread(void) { 1091 char dummy; 1092 // If called before init complete, thread stack bottom will be null. 1093 // Can be called if fatal error occurs before initialization. 1094 if (initial_thread_stack_bottom() == NULL) return false; 1095 assert(initial_thread_stack_bottom() != NULL && 1096 initial_thread_stack_size() != 0, 1097 "os::init did not locate initial thread's stack region"); 1098 if ((address)&dummy >= initial_thread_stack_bottom() && 1099 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) 1100 return true; 1101 else return false; 1102 } 1103 1104 // Find the virtual memory area that contains addr 1105 static bool find_vma(address addr, address* vma_low, address* vma_high) { 1106 FILE *fp = fopen("/proc/self/maps", "r"); 1107 if (fp) { 1108 address low, high; 1109 while (!feof(fp)) { 1110 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1111 if (low <= addr && addr < high) { 1112 if (vma_low) *vma_low = low; 1113 if (vma_high) *vma_high = high; 1114 fclose (fp); 1115 return true; 1116 } 1117 } 1118 for (;;) { 1119 int ch = fgetc(fp); 1120 if (ch == EOF || ch == (int)'\n') break; 1121 } 1122 } 1123 fclose(fp); 1124 } 1125 return false; 1126 } 1127 1128 // Locate initial thread stack. This special handling of initial thread stack 1129 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 1130 // bogus value for initial thread. 1131 void os::Linux::capture_initial_stack(size_t max_size) { 1132 // stack size is the easy part, get it from RLIMIT_STACK 1133 size_t stack_size; 1134 struct rlimit rlim; 1135 getrlimit(RLIMIT_STACK, &rlim); 1136 stack_size = rlim.rlim_cur; 1137 1138 // 6308388: a bug in ld.so will relocate its own .data section to the 1139 // lower end of primordial stack; reduce ulimit -s value a little bit 1140 // so we won't install guard page on ld.so's data section. 1141 stack_size -= 2 * page_size(); 1142 1143 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 1144 // 7.1, in both cases we will get 2G in return value. 1145 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 1146 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 1147 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 1148 // in case other parts in glibc still assumes 2M max stack size. 1149 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 1150 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 1151 if (stack_size > 2 * K * K IA64_ONLY(*2)) 1152 stack_size = 2 * K * K IA64_ONLY(*2); 1153 // Try to figure out where the stack base (top) is. This is harder. 1154 // 1155 // When an application is started, glibc saves the initial stack pointer in 1156 // a global variable "__libc_stack_end", which is then used by system 1157 // libraries. __libc_stack_end should be pretty close to stack top. The 1158 // variable is available since the very early days. However, because it is 1159 // a private interface, it could disappear in the future. 1160 // 1161 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1162 // to __libc_stack_end, it is very close to stack top, but isn't the real 1163 // stack top. Note that /proc may not exist if VM is running as a chroot 1164 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1165 // /proc/<pid>/stat could change in the future (though unlikely). 1166 // 1167 // We try __libc_stack_end first. If that doesn't work, look for 1168 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1169 // as a hint, which should work well in most cases. 1170 1171 uintptr_t stack_start; 1172 1173 // try __libc_stack_end first 1174 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1175 if (p && *p) { 1176 stack_start = *p; 1177 } else { 1178 // see if we can get the start_stack field from /proc/self/stat 1179 FILE *fp; 1180 int pid; 1181 char state; 1182 int ppid; 1183 int pgrp; 1184 int session; 1185 int nr; 1186 int tpgrp; 1187 unsigned long flags; 1188 unsigned long minflt; 1189 unsigned long cminflt; 1190 unsigned long majflt; 1191 unsigned long cmajflt; 1192 unsigned long utime; 1193 unsigned long stime; 1194 long cutime; 1195 long cstime; 1196 long prio; 1197 long nice; 1198 long junk; 1199 long it_real; 1200 uintptr_t start; 1201 uintptr_t vsize; 1202 intptr_t rss; 1203 uintptr_t rsslim; 1204 uintptr_t scodes; 1205 uintptr_t ecode; 1206 int i; 1207 1208 // Figure what the primordial thread stack base is. Code is inspired 1209 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1210 // followed by command name surrounded by parentheses, state, etc. 1211 char stat[2048]; 1212 int statlen; 1213 1214 fp = fopen("/proc/self/stat", "r"); 1215 if (fp) { 1216 statlen = fread(stat, 1, 2047, fp); 1217 stat[statlen] = '\0'; 1218 fclose(fp); 1219 1220 // Skip pid and the command string. Note that we could be dealing with 1221 // weird command names, e.g. user could decide to rename java launcher 1222 // to "java 1.4.2 :)", then the stat file would look like 1223 // 1234 (java 1.4.2 :)) R ... ... 1224 // We don't really need to know the command string, just find the last 1225 // occurrence of ")" and then start parsing from there. See bug 4726580. 1226 char * s = strrchr(stat, ')'); 1227 1228 i = 0; 1229 if (s) { 1230 // Skip blank chars 1231 do s++; while (isspace(*s)); 1232 1233 #define _UFM UINTX_FORMAT 1234 #define _DFM INTX_FORMAT 1235 1236 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */ 1237 /* 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 */ 1238 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM, 1239 &state, /* 3 %c */ 1240 &ppid, /* 4 %d */ 1241 &pgrp, /* 5 %d */ 1242 &session, /* 6 %d */ 1243 &nr, /* 7 %d */ 1244 &tpgrp, /* 8 %d */ 1245 &flags, /* 9 %lu */ 1246 &minflt, /* 10 %lu */ 1247 &cminflt, /* 11 %lu */ 1248 &majflt, /* 12 %lu */ 1249 &cmajflt, /* 13 %lu */ 1250 &utime, /* 14 %lu */ 1251 &stime, /* 15 %lu */ 1252 &cutime, /* 16 %ld */ 1253 &cstime, /* 17 %ld */ 1254 &prio, /* 18 %ld */ 1255 &nice, /* 19 %ld */ 1256 &junk, /* 20 %ld */ 1257 &it_real, /* 21 %ld */ 1258 &start, /* 22 UINTX_FORMAT */ 1259 &vsize, /* 23 UINTX_FORMAT */ 1260 &rss, /* 24 INTX_FORMAT */ 1261 &rsslim, /* 25 UINTX_FORMAT */ 1262 &scodes, /* 26 UINTX_FORMAT */ 1263 &ecode, /* 27 UINTX_FORMAT */ 1264 &stack_start); /* 28 UINTX_FORMAT */ 1265 } 1266 1267 #undef _UFM 1268 #undef _DFM 1269 1270 if (i != 28 - 2) { 1271 assert(false, "Bad conversion from /proc/self/stat"); 1272 // product mode - assume we are the initial thread, good luck in the 1273 // embedded case. 1274 warning("Can't detect initial thread stack location - bad conversion"); 1275 stack_start = (uintptr_t) &rlim; 1276 } 1277 } else { 1278 // For some reason we can't open /proc/self/stat (for example, running on 1279 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1280 // most cases, so don't abort: 1281 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1282 stack_start = (uintptr_t) &rlim; 1283 } 1284 } 1285 1286 // Now we have a pointer (stack_start) very close to the stack top, the 1287 // next thing to do is to figure out the exact location of stack top. We 1288 // can find out the virtual memory area that contains stack_start by 1289 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1290 // and its upper limit is the real stack top. (again, this would fail if 1291 // running inside chroot, because /proc may not exist.) 1292 1293 uintptr_t stack_top; 1294 address low, high; 1295 if (find_vma((address)stack_start, &low, &high)) { 1296 // success, "high" is the true stack top. (ignore "low", because initial 1297 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1298 stack_top = (uintptr_t)high; 1299 } else { 1300 // failed, likely because /proc/self/maps does not exist 1301 warning("Can't detect initial thread stack location - find_vma failed"); 1302 // best effort: stack_start is normally within a few pages below the real 1303 // stack top, use it as stack top, and reduce stack size so we won't put 1304 // guard page outside stack. 1305 stack_top = stack_start; 1306 stack_size -= 16 * page_size(); 1307 } 1308 1309 // stack_top could be partially down the page so align it 1310 stack_top = align_size_up(stack_top, page_size()); 1311 1312 if (max_size && stack_size > max_size) { 1313 _initial_thread_stack_size = max_size; 1314 } else { 1315 _initial_thread_stack_size = stack_size; 1316 } 1317 1318 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1319 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1320 } 1321 1322 //////////////////////////////////////////////////////////////////////////////// 1323 // time support 1324 1325 // Time since start-up in seconds to a fine granularity. 1326 // Used by VMSelfDestructTimer and the MemProfiler. 1327 double os::elapsedTime() { 1328 1329 return (double)(os::elapsed_counter()) * 0.000001; 1330 } 1331 1332 jlong os::elapsed_counter() { 1333 timeval time; 1334 int status = gettimeofday(&time, NULL); 1335 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count; 1336 } 1337 1338 jlong os::elapsed_frequency() { 1339 return (1000 * 1000); 1340 } 1341 1342 // For now, we say that linux does not support vtime. I have no idea 1343 // whether it can actually be made to (DLD, 9/13/05). 1344 1345 bool os::supports_vtime() { return false; } 1346 bool os::enable_vtime() { return false; } 1347 bool os::vtime_enabled() { return false; } 1348 double os::elapsedVTime() { 1349 // better than nothing, but not much 1350 return elapsedTime(); 1351 } 1352 1353 jlong os::javaTimeMillis() { 1354 timeval time; 1355 int status = gettimeofday(&time, NULL); 1356 assert(status != -1, "linux error"); 1357 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1358 } 1359 1360 #ifndef CLOCK_MONOTONIC 1361 #define CLOCK_MONOTONIC (1) 1362 #endif 1363 1364 void os::Linux::clock_init() { 1365 // we do dlopen's in this particular order due to bug in linux 1366 // dynamical loader (see 6348968) leading to crash on exit 1367 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1368 if (handle == NULL) { 1369 handle = dlopen("librt.so", RTLD_LAZY); 1370 } 1371 1372 if (handle) { 1373 int (*clock_getres_func)(clockid_t, struct timespec*) = 1374 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1375 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1376 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1377 if (clock_getres_func && clock_gettime_func) { 1378 // See if monotonic clock is supported by the kernel. Note that some 1379 // early implementations simply return kernel jiffies (updated every 1380 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1381 // for nano time (though the monotonic property is still nice to have). 1382 // It's fixed in newer kernels, however clock_getres() still returns 1383 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1384 // resolution for now. Hopefully as people move to new kernels, this 1385 // won't be a problem. 1386 struct timespec res; 1387 struct timespec tp; 1388 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1389 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1390 // yes, monotonic clock is supported 1391 _clock_gettime = clock_gettime_func; 1392 } else { 1393 // close librt if there is no monotonic clock 1394 dlclose(handle); 1395 } 1396 } 1397 } 1398 } 1399 1400 #ifndef SYS_clock_getres 1401 1402 #if defined(IA32) || defined(AMD64) 1403 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1404 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1405 #else 1406 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1407 #define sys_clock_getres(x,y) -1 1408 #endif 1409 1410 #else 1411 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1412 #endif 1413 1414 void os::Linux::fast_thread_clock_init() { 1415 if (!UseLinuxPosixThreadCPUClocks) { 1416 return; 1417 } 1418 clockid_t clockid; 1419 struct timespec tp; 1420 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1421 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1422 1423 // Switch to using fast clocks for thread cpu time if 1424 // the sys_clock_getres() returns 0 error code. 1425 // Note, that some kernels may support the current thread 1426 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1427 // returned by the pthread_getcpuclockid(). 1428 // If the fast Posix clocks are supported then the sys_clock_getres() 1429 // must return at least tp.tv_sec == 0 which means a resolution 1430 // better than 1 sec. This is extra check for reliability. 1431 1432 if(pthread_getcpuclockid_func && 1433 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1434 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1435 1436 _supports_fast_thread_cpu_time = true; 1437 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1438 } 1439 } 1440 1441 jlong os::javaTimeNanos() { 1442 if (Linux::supports_monotonic_clock()) { 1443 struct timespec tp; 1444 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1445 assert(status == 0, "gettime error"); 1446 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1447 return result; 1448 } else { 1449 timeval time; 1450 int status = gettimeofday(&time, NULL); 1451 assert(status != -1, "linux error"); 1452 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1453 return 1000 * usecs; 1454 } 1455 } 1456 1457 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1458 if (Linux::supports_monotonic_clock()) { 1459 info_ptr->max_value = ALL_64_BITS; 1460 1461 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1462 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1463 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1464 } else { 1465 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1466 info_ptr->max_value = ALL_64_BITS; 1467 1468 // gettimeofday is a real time clock so it skips 1469 info_ptr->may_skip_backward = true; 1470 info_ptr->may_skip_forward = true; 1471 } 1472 1473 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1474 } 1475 1476 // Return the real, user, and system times in seconds from an 1477 // arbitrary fixed point in the past. 1478 bool os::getTimesSecs(double* process_real_time, 1479 double* process_user_time, 1480 double* process_system_time) { 1481 struct tms ticks; 1482 clock_t real_ticks = times(&ticks); 1483 1484 if (real_ticks == (clock_t) (-1)) { 1485 return false; 1486 } else { 1487 double ticks_per_second = (double) clock_tics_per_sec; 1488 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1489 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1490 *process_real_time = ((double) real_ticks) / ticks_per_second; 1491 1492 return true; 1493 } 1494 } 1495 1496 1497 char * os::local_time_string(char *buf, size_t buflen) { 1498 struct tm t; 1499 time_t long_time; 1500 time(&long_time); 1501 localtime_r(&long_time, &t); 1502 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1503 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1504 t.tm_hour, t.tm_min, t.tm_sec); 1505 return buf; 1506 } 1507 1508 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1509 return localtime_r(clock, res); 1510 } 1511 1512 //////////////////////////////////////////////////////////////////////////////// 1513 // runtime exit support 1514 1515 // Note: os::shutdown() might be called very early during initialization, or 1516 // called from signal handler. Before adding something to os::shutdown(), make 1517 // sure it is async-safe and can handle partially initialized VM. 1518 void os::shutdown() { 1519 1520 // allow PerfMemory to attempt cleanup of any persistent resources 1521 perfMemory_exit(); 1522 1523 // needs to remove object in file system 1524 AttachListener::abort(); 1525 1526 // flush buffered output, finish log files 1527 ostream_abort(); 1528 1529 // Check for abort hook 1530 abort_hook_t abort_hook = Arguments::abort_hook(); 1531 if (abort_hook != NULL) { 1532 abort_hook(); 1533 } 1534 1535 } 1536 1537 // Note: os::abort() might be called very early during initialization, or 1538 // called from signal handler. Before adding something to os::abort(), make 1539 // sure it is async-safe and can handle partially initialized VM. 1540 void os::abort(bool dump_core) { 1541 os::shutdown(); 1542 if (dump_core) { 1543 #ifndef PRODUCT 1544 fdStream out(defaultStream::output_fd()); 1545 out.print_raw("Current thread is "); 1546 char buf[16]; 1547 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1548 out.print_raw_cr(buf); 1549 out.print_raw_cr("Dumping core ..."); 1550 #endif 1551 ::abort(); // dump core 1552 } 1553 1554 ::exit(1); 1555 } 1556 1557 // Die immediately, no exit hook, no abort hook, no cleanup. 1558 void os::die() { 1559 // _exit() on LinuxThreads only kills current thread 1560 ::abort(); 1561 } 1562 1563 // unused on linux for now. 1564 void os::set_error_file(const char *logfile) {} 1565 1566 1567 // This method is a copy of JDK's sysGetLastErrorString 1568 // from src/solaris/hpi/src/system_md.c 1569 1570 size_t os::lasterror(char *buf, size_t len) { 1571 1572 if (errno == 0) return 0; 1573 1574 const char *s = ::strerror(errno); 1575 size_t n = ::strlen(s); 1576 if (n >= len) { 1577 n = len - 1; 1578 } 1579 ::strncpy(buf, s, n); 1580 buf[n] = '\0'; 1581 return n; 1582 } 1583 1584 intx os::current_thread_id() { return (intx)pthread_self(); } 1585 int os::current_process_id() { 1586 1587 // Under the old linux thread library, linux gives each thread 1588 // its own process id. Because of this each thread will return 1589 // a different pid if this method were to return the result 1590 // of getpid(2). Linux provides no api that returns the pid 1591 // of the launcher thread for the vm. This implementation 1592 // returns a unique pid, the pid of the launcher thread 1593 // that starts the vm 'process'. 1594 1595 // Under the NPTL, getpid() returns the same pid as the 1596 // launcher thread rather than a unique pid per thread. 1597 // Use gettid() if you want the old pre NPTL behaviour. 1598 1599 // if you are looking for the result of a call to getpid() that 1600 // returns a unique pid for the calling thread, then look at the 1601 // OSThread::thread_id() method in osThread_linux.hpp file 1602 1603 return (int)(_initial_pid ? _initial_pid : getpid()); 1604 } 1605 1606 // DLL functions 1607 1608 const char* os::dll_file_extension() { return ".so"; } 1609 1610 // This must be hard coded because it's the system's temporary 1611 // directory not the java application's temp directory, ala java.io.tmpdir. 1612 const char* os::get_temp_directory() { return "/tmp"; } 1613 1614 static bool file_exists(const char* filename) { 1615 struct stat statbuf; 1616 if (filename == NULL || strlen(filename) == 0) { 1617 return false; 1618 } 1619 return os::stat(filename, &statbuf) == 0; 1620 } 1621 1622 bool os::dll_build_name(char* buffer, size_t buflen, 1623 const char* pname, const char* fname) { 1624 bool retval = false; 1625 // Copied from libhpi 1626 const size_t pnamelen = pname ? strlen(pname) : 0; 1627 1628 // Return error on buffer overflow. 1629 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1630 return retval; 1631 } 1632 1633 if (pnamelen == 0) { 1634 snprintf(buffer, buflen, "lib%s.so", fname); 1635 retval = true; 1636 } else if (strchr(pname, *os::path_separator()) != NULL) { 1637 int n; 1638 char** pelements = split_path(pname, &n); 1639 if (pelements == NULL) { 1640 return false; 1641 } 1642 for (int i = 0 ; i < n ; i++) { 1643 // Really shouldn't be NULL, but check can't hurt 1644 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1645 continue; // skip the empty path values 1646 } 1647 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1648 if (file_exists(buffer)) { 1649 retval = true; 1650 break; 1651 } 1652 } 1653 // release the storage 1654 for (int i = 0 ; i < n ; i++) { 1655 if (pelements[i] != NULL) { 1656 FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal); 1657 } 1658 } 1659 if (pelements != NULL) { 1660 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal); 1661 } 1662 } else { 1663 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1664 retval = true; 1665 } 1666 return retval; 1667 } 1668 1669 // check if addr is inside libjvm.so 1670 bool os::address_is_in_vm(address addr) { 1671 static address libjvm_base_addr; 1672 Dl_info dlinfo; 1673 1674 if (libjvm_base_addr == NULL) { 1675 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo); 1676 libjvm_base_addr = (address)dlinfo.dli_fbase; 1677 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1678 } 1679 1680 if (dladdr((void *)addr, &dlinfo)) { 1681 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1682 } 1683 1684 return false; 1685 } 1686 1687 bool os::dll_address_to_function_name(address addr, char *buf, 1688 int buflen, int *offset) { 1689 Dl_info dlinfo; 1690 1691 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) { 1692 if (buf != NULL) { 1693 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) { 1694 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1695 } 1696 } 1697 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1698 return true; 1699 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) { 1700 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1701 buf, buflen, offset, dlinfo.dli_fname)) { 1702 return true; 1703 } 1704 } 1705 1706 if (buf != NULL) buf[0] = '\0'; 1707 if (offset != NULL) *offset = -1; 1708 return false; 1709 } 1710 1711 struct _address_to_library_name { 1712 address addr; // input : memory address 1713 size_t buflen; // size of fname 1714 char* fname; // output: library name 1715 address base; // library base addr 1716 }; 1717 1718 static int address_to_library_name_callback(struct dl_phdr_info *info, 1719 size_t size, void *data) { 1720 int i; 1721 bool found = false; 1722 address libbase = NULL; 1723 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1724 1725 // iterate through all loadable segments 1726 for (i = 0; i < info->dlpi_phnum; i++) { 1727 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1728 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1729 // base address of a library is the lowest address of its loaded 1730 // segments. 1731 if (libbase == NULL || libbase > segbase) { 1732 libbase = segbase; 1733 } 1734 // see if 'addr' is within current segment 1735 if (segbase <= d->addr && 1736 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1737 found = true; 1738 } 1739 } 1740 } 1741 1742 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1743 // so dll_address_to_library_name() can fall through to use dladdr() which 1744 // can figure out executable name from argv[0]. 1745 if (found && info->dlpi_name && info->dlpi_name[0]) { 1746 d->base = libbase; 1747 if (d->fname) { 1748 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1749 } 1750 return 1; 1751 } 1752 return 0; 1753 } 1754 1755 bool os::dll_address_to_library_name(address addr, char* buf, 1756 int buflen, int* offset) { 1757 Dl_info dlinfo; 1758 struct _address_to_library_name data; 1759 1760 // There is a bug in old glibc dladdr() implementation that it could resolve 1761 // to wrong library name if the .so file has a base address != NULL. Here 1762 // we iterate through the program headers of all loaded libraries to find 1763 // out which library 'addr' really belongs to. This workaround can be 1764 // removed once the minimum requirement for glibc is moved to 2.3.x. 1765 data.addr = addr; 1766 data.fname = buf; 1767 data.buflen = buflen; 1768 data.base = NULL; 1769 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1770 1771 if (rslt) { 1772 // buf already contains library name 1773 if (offset) *offset = addr - data.base; 1774 return true; 1775 } else if (dladdr((void*)addr, &dlinfo)){ 1776 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1777 if (offset) *offset = addr - (address)dlinfo.dli_fbase; 1778 return true; 1779 } else { 1780 if (buf) buf[0] = '\0'; 1781 if (offset) *offset = -1; 1782 return false; 1783 } 1784 } 1785 1786 // Loads .dll/.so and 1787 // in case of error it checks if .dll/.so was built for the 1788 // same architecture as Hotspot is running on 1789 1790 1791 // Remember the stack's state. The Linux dynamic linker will change 1792 // the stack to 'executable' at most once, so we must safepoint only once. 1793 bool os::Linux::_stack_is_executable = false; 1794 1795 // VM operation that loads a library. This is necessary if stack protection 1796 // of the Java stacks can be lost during loading the library. If we 1797 // do not stop the Java threads, they can stack overflow before the stacks 1798 // are protected again. 1799 class VM_LinuxDllLoad: public VM_Operation { 1800 private: 1801 const char *_filename; 1802 char *_ebuf; 1803 int _ebuflen; 1804 void *_lib; 1805 public: 1806 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1807 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1808 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1809 void doit() { 1810 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1811 os::Linux::_stack_is_executable = true; 1812 } 1813 void* loaded_library() { return _lib; } 1814 }; 1815 1816 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) 1817 { 1818 void * result = NULL; 1819 bool load_attempted = false; 1820 1821 // Check whether the library to load might change execution rights 1822 // of the stack. If they are changed, the protection of the stack 1823 // guard pages will be lost. We need a safepoint to fix this. 1824 // 1825 // See Linux man page execstack(8) for more info. 1826 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1827 ElfFile ef(filename); 1828 if (!ef.specifies_noexecstack()) { 1829 if (!is_init_completed()) { 1830 os::Linux::_stack_is_executable = true; 1831 // This is OK - No Java threads have been created yet, and hence no 1832 // stack guard pages to fix. 1833 // 1834 // This should happen only when you are building JDK7 using a very 1835 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1836 // 1837 // Dynamic loader will make all stacks executable after 1838 // this function returns, and will not do that again. 1839 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1840 } else { 1841 warning("You have loaded library %s which might have disabled stack guard. " 1842 "The VM will try to fix the stack guard now.\n" 1843 "It's highly recommended that you fix the library with " 1844 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1845 filename); 1846 1847 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1848 JavaThread *jt = JavaThread::current(); 1849 if (jt->thread_state() != _thread_in_native) { 1850 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1851 // that requires ExecStack. Cannot enter safe point. Let's give up. 1852 warning("Unable to fix stack guard. Giving up."); 1853 } else { 1854 if (!LoadExecStackDllInVMThread) { 1855 // This is for the case where the DLL has an static 1856 // constructor function that executes JNI code. We cannot 1857 // load such DLLs in the VMThread. 1858 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1859 } 1860 1861 ThreadInVMfromNative tiv(jt); 1862 debug_only(VMNativeEntryWrapper vew;) 1863 1864 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1865 VMThread::execute(&op); 1866 if (LoadExecStackDllInVMThread) { 1867 result = op.loaded_library(); 1868 } 1869 load_attempted = true; 1870 } 1871 } 1872 } 1873 } 1874 1875 if (!load_attempted) { 1876 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1877 } 1878 1879 if (result != NULL) { 1880 // Successful loading 1881 return result; 1882 } 1883 1884 Elf32_Ehdr elf_head; 1885 int diag_msg_max_length=ebuflen-strlen(ebuf); 1886 char* diag_msg_buf=ebuf+strlen(ebuf); 1887 1888 if (diag_msg_max_length==0) { 1889 // No more space in ebuf for additional diagnostics message 1890 return NULL; 1891 } 1892 1893 1894 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1895 1896 if (file_descriptor < 0) { 1897 // Can't open library, report dlerror() message 1898 return NULL; 1899 } 1900 1901 bool failed_to_read_elf_head= 1902 (sizeof(elf_head)!= 1903 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ; 1904 1905 ::close(file_descriptor); 1906 if (failed_to_read_elf_head) { 1907 // file i/o error - report dlerror() msg 1908 return NULL; 1909 } 1910 1911 typedef struct { 1912 Elf32_Half code; // Actual value as defined in elf.h 1913 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1914 char elf_class; // 32 or 64 bit 1915 char endianess; // MSB or LSB 1916 char* name; // String representation 1917 } arch_t; 1918 1919 #ifndef EM_486 1920 #define EM_486 6 /* Intel 80486 */ 1921 #endif 1922 1923 static const arch_t arch_array[]={ 1924 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1925 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1926 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1927 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1928 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1929 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1930 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1931 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1932 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1933 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1934 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1935 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1936 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1937 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1938 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1939 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"} 1940 }; 1941 1942 #if (defined IA32) 1943 static Elf32_Half running_arch_code=EM_386; 1944 #elif (defined AMD64) 1945 static Elf32_Half running_arch_code=EM_X86_64; 1946 #elif (defined IA64) 1947 static Elf32_Half running_arch_code=EM_IA_64; 1948 #elif (defined __sparc) && (defined _LP64) 1949 static Elf32_Half running_arch_code=EM_SPARCV9; 1950 #elif (defined __sparc) && (!defined _LP64) 1951 static Elf32_Half running_arch_code=EM_SPARC; 1952 #elif (defined __powerpc64__) 1953 static Elf32_Half running_arch_code=EM_PPC64; 1954 #elif (defined __powerpc__) 1955 static Elf32_Half running_arch_code=EM_PPC; 1956 #elif (defined ARM) 1957 static Elf32_Half running_arch_code=EM_ARM; 1958 #elif (defined S390) 1959 static Elf32_Half running_arch_code=EM_S390; 1960 #elif (defined ALPHA) 1961 static Elf32_Half running_arch_code=EM_ALPHA; 1962 #elif (defined MIPSEL) 1963 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1964 #elif (defined PARISC) 1965 static Elf32_Half running_arch_code=EM_PARISC; 1966 #elif (defined MIPS) 1967 static Elf32_Half running_arch_code=EM_MIPS; 1968 #elif (defined M68K) 1969 static Elf32_Half running_arch_code=EM_68K; 1970 #else 1971 #error Method os::dll_load requires that one of following is defined:\ 1972 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K 1973 #endif 1974 1975 // Identify compatability class for VM's architecture and library's architecture 1976 // Obtain string descriptions for architectures 1977 1978 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1979 int running_arch_index=-1; 1980 1981 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) { 1982 if (running_arch_code == arch_array[i].code) { 1983 running_arch_index = i; 1984 } 1985 if (lib_arch.code == arch_array[i].code) { 1986 lib_arch.compat_class = arch_array[i].compat_class; 1987 lib_arch.name = arch_array[i].name; 1988 } 1989 } 1990 1991 assert(running_arch_index != -1, 1992 "Didn't find running architecture code (running_arch_code) in arch_array"); 1993 if (running_arch_index == -1) { 1994 // Even though running architecture detection failed 1995 // we may still continue with reporting dlerror() message 1996 return NULL; 1997 } 1998 1999 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 2000 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 2001 return NULL; 2002 } 2003 2004 #ifndef S390 2005 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 2006 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 2007 return NULL; 2008 } 2009 #endif // !S390 2010 2011 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 2012 if ( lib_arch.name!=NULL ) { 2013 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 2014 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 2015 lib_arch.name, arch_array[running_arch_index].name); 2016 } else { 2017 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 2018 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 2019 lib_arch.code, 2020 arch_array[running_arch_index].name); 2021 } 2022 } 2023 2024 return NULL; 2025 } 2026 2027 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, int ebuflen) { 2028 void * result = ::dlopen(filename, RTLD_LAZY); 2029 if (result == NULL) { 2030 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 2031 ebuf[ebuflen-1] = '\0'; 2032 } 2033 return result; 2034 } 2035 2036 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, int ebuflen) { 2037 void * result = NULL; 2038 if (LoadExecStackDllInVMThread) { 2039 result = dlopen_helper(filename, ebuf, ebuflen); 2040 } 2041 2042 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 2043 // library that requires an executable stack, or which does not have this 2044 // stack attribute set, dlopen changes the stack attribute to executable. The 2045 // read protection of the guard pages gets lost. 2046 // 2047 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 2048 // may have been queued at the same time. 2049 2050 if (!_stack_is_executable) { 2051 JavaThread *jt = Threads::first(); 2052 2053 while (jt) { 2054 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 2055 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions 2056 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(), 2057 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) { 2058 warning("Attempt to reguard stack yellow zone failed."); 2059 } 2060 } 2061 jt = jt->next(); 2062 } 2063 } 2064 2065 return result; 2066 } 2067 2068 /* 2069 * glibc-2.0 libdl is not MT safe. If you are building with any glibc, 2070 * chances are you might want to run the generated bits against glibc-2.0 2071 * libdl.so, so always use locking for any version of glibc. 2072 */ 2073 void* os::dll_lookup(void* handle, const char* name) { 2074 pthread_mutex_lock(&dl_mutex); 2075 void* res = dlsym(handle, name); 2076 pthread_mutex_unlock(&dl_mutex); 2077 return res; 2078 } 2079 2080 2081 static bool _print_ascii_file(const char* filename, outputStream* st) { 2082 int fd = ::open(filename, O_RDONLY); 2083 if (fd == -1) { 2084 return false; 2085 } 2086 2087 char buf[32]; 2088 int bytes; 2089 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 2090 st->print_raw(buf, bytes); 2091 } 2092 2093 ::close(fd); 2094 2095 return true; 2096 } 2097 2098 void os::print_dll_info(outputStream *st) { 2099 st->print_cr("Dynamic libraries:"); 2100 2101 char fname[32]; 2102 pid_t pid = os::Linux::gettid(); 2103 2104 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 2105 2106 if (!_print_ascii_file(fname, st)) { 2107 st->print("Can not get library information for pid = %d\n", pid); 2108 } 2109 } 2110 2111 void os::print_os_info_brief(outputStream* st) { 2112 os::Linux::print_distro_info(st); 2113 2114 os::Posix::print_uname_info(st); 2115 2116 os::Linux::print_libversion_info(st); 2117 2118 } 2119 2120 void os::print_os_info(outputStream* st) { 2121 st->print("OS:"); 2122 2123 os::Linux::print_distro_info(st); 2124 2125 os::Posix::print_uname_info(st); 2126 2127 // Print warning if unsafe chroot environment detected 2128 if (unsafe_chroot_detected) { 2129 st->print("WARNING!! "); 2130 st->print_cr(unstable_chroot_error); 2131 } 2132 2133 os::Linux::print_libversion_info(st); 2134 2135 os::Posix::print_rlimit_info(st); 2136 2137 os::Posix::print_load_average(st); 2138 2139 os::Linux::print_full_memory_info(st); 2140 } 2141 2142 // Try to identify popular distros. 2143 // Most Linux distributions have /etc/XXX-release file, which contains 2144 // the OS version string. Some have more than one /etc/XXX-release file 2145 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.), 2146 // so the order is important. 2147 void os::Linux::print_distro_info(outputStream* st) { 2148 if (!_print_ascii_file("/etc/mandrake-release", st) && 2149 !_print_ascii_file("/etc/sun-release", st) && 2150 !_print_ascii_file("/etc/redhat-release", st) && 2151 !_print_ascii_file("/etc/SuSE-release", st) && 2152 !_print_ascii_file("/etc/turbolinux-release", st) && 2153 !_print_ascii_file("/etc/gentoo-release", st) && 2154 !_print_ascii_file("/etc/debian_version", st) && 2155 !_print_ascii_file("/etc/ltib-release", st) && 2156 !_print_ascii_file("/etc/angstrom-version", st)) { 2157 st->print("Linux"); 2158 } 2159 st->cr(); 2160 } 2161 2162 void os::Linux::print_libversion_info(outputStream* st) { 2163 // libc, pthread 2164 st->print("libc:"); 2165 st->print(os::Linux::glibc_version()); st->print(" "); 2166 st->print(os::Linux::libpthread_version()); st->print(" "); 2167 if (os::Linux::is_LinuxThreads()) { 2168 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed"); 2169 } 2170 st->cr(); 2171 } 2172 2173 void os::Linux::print_full_memory_info(outputStream* st) { 2174 st->print("\n/proc/meminfo:\n"); 2175 _print_ascii_file("/proc/meminfo", st); 2176 st->cr(); 2177 } 2178 2179 void os::print_memory_info(outputStream* st) { 2180 2181 st->print("Memory:"); 2182 st->print(" %dk page", os::vm_page_size()>>10); 2183 2184 // values in struct sysinfo are "unsigned long" 2185 struct sysinfo si; 2186 sysinfo(&si); 2187 2188 st->print(", physical " UINT64_FORMAT "k", 2189 os::physical_memory() >> 10); 2190 st->print("(" UINT64_FORMAT "k free)", 2191 os::available_memory() >> 10); 2192 st->print(", swap " UINT64_FORMAT "k", 2193 ((jlong)si.totalswap * si.mem_unit) >> 10); 2194 st->print("(" UINT64_FORMAT "k free)", 2195 ((jlong)si.freeswap * si.mem_unit) >> 10); 2196 st->cr(); 2197 } 2198 2199 void os::pd_print_cpu_info(outputStream* st) { 2200 st->print("\n/proc/cpuinfo:\n"); 2201 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2202 st->print(" <Not Available>"); 2203 } 2204 st->cr(); 2205 } 2206 2207 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific 2208 // but they're the same for all the linux arch that we support 2209 // and they're the same for solaris but there's no common place to put this. 2210 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR", 2211 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG", 2212 "ILL_COPROC", "ILL_BADSTK" }; 2213 2214 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV", 2215 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES", 2216 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" }; 2217 2218 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" }; 2219 2220 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" }; 2221 2222 void os::print_siginfo(outputStream* st, void* siginfo) { 2223 st->print("siginfo:"); 2224 2225 const int buflen = 100; 2226 char buf[buflen]; 2227 siginfo_t *si = (siginfo_t*)siginfo; 2228 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen)); 2229 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) { 2230 st->print("si_errno=%s", buf); 2231 } else { 2232 st->print("si_errno=%d", si->si_errno); 2233 } 2234 const int c = si->si_code; 2235 assert(c > 0, "unexpected si_code"); 2236 switch (si->si_signo) { 2237 case SIGILL: 2238 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]); 2239 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2240 break; 2241 case SIGFPE: 2242 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]); 2243 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2244 break; 2245 case SIGSEGV: 2246 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]); 2247 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2248 break; 2249 case SIGBUS: 2250 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]); 2251 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2252 break; 2253 default: 2254 st->print(", si_code=%d", si->si_code); 2255 // no si_addr 2256 } 2257 2258 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2259 UseSharedSpaces) { 2260 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2261 if (mapinfo->is_in_shared_space(si->si_addr)) { 2262 st->print("\n\nError accessing class data sharing archive." \ 2263 " Mapped file inaccessible during execution, " \ 2264 " possible disk/network problem."); 2265 } 2266 } 2267 st->cr(); 2268 } 2269 2270 2271 static void print_signal_handler(outputStream* st, int sig, 2272 char* buf, size_t buflen); 2273 2274 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2275 st->print_cr("Signal Handlers:"); 2276 print_signal_handler(st, SIGSEGV, buf, buflen); 2277 print_signal_handler(st, SIGBUS , buf, buflen); 2278 print_signal_handler(st, SIGFPE , buf, buflen); 2279 print_signal_handler(st, SIGPIPE, buf, buflen); 2280 print_signal_handler(st, SIGXFSZ, buf, buflen); 2281 print_signal_handler(st, SIGILL , buf, buflen); 2282 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2283 print_signal_handler(st, SR_signum, buf, buflen); 2284 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2285 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2286 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2287 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2288 } 2289 2290 static char saved_jvm_path[MAXPATHLEN] = {0}; 2291 2292 // Find the full path to the current module, libjvm.so 2293 void os::jvm_path(char *buf, jint buflen) { 2294 // Error checking. 2295 if (buflen < MAXPATHLEN) { 2296 assert(false, "must use a large-enough buffer"); 2297 buf[0] = '\0'; 2298 return; 2299 } 2300 // Lazy resolve the path to current module. 2301 if (saved_jvm_path[0] != 0) { 2302 strcpy(buf, saved_jvm_path); 2303 return; 2304 } 2305 2306 char dli_fname[MAXPATHLEN]; 2307 bool ret = dll_address_to_library_name( 2308 CAST_FROM_FN_PTR(address, os::jvm_path), 2309 dli_fname, sizeof(dli_fname), NULL); 2310 assert(ret != 0, "cannot locate libjvm"); 2311 char *rp = realpath(dli_fname, buf); 2312 if (rp == NULL) 2313 return; 2314 2315 if (Arguments::created_by_gamma_launcher()) { 2316 // Support for the gamma launcher. Typical value for buf is 2317 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at 2318 // the right place in the string, then assume we are installed in a JDK and 2319 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix 2320 // up the path so it looks like libjvm.so is installed there (append a 2321 // fake suffix hotspot/libjvm.so). 2322 const char *p = buf + strlen(buf) - 1; 2323 for (int count = 0; p > buf && count < 5; ++count) { 2324 for (--p; p > buf && *p != '/'; --p) 2325 /* empty */ ; 2326 } 2327 2328 if (strncmp(p, "/jre/lib/", 9) != 0) { 2329 // Look for JAVA_HOME in the environment. 2330 char* java_home_var = ::getenv("JAVA_HOME"); 2331 if (java_home_var != NULL && java_home_var[0] != 0) { 2332 char* jrelib_p; 2333 int len; 2334 2335 // Check the current module name "libjvm.so". 2336 p = strrchr(buf, '/'); 2337 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2338 2339 rp = realpath(java_home_var, buf); 2340 if (rp == NULL) 2341 return; 2342 2343 // determine if this is a legacy image or modules image 2344 // modules image doesn't have "jre" subdirectory 2345 len = strlen(buf); 2346 jrelib_p = buf + len; 2347 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2348 if (0 != access(buf, F_OK)) { 2349 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2350 } 2351 2352 if (0 == access(buf, F_OK)) { 2353 // Use current module name "libjvm.so" 2354 len = strlen(buf); 2355 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2356 } else { 2357 // Go back to path of .so 2358 rp = realpath(dli_fname, buf); 2359 if (rp == NULL) 2360 return; 2361 } 2362 } 2363 } 2364 } 2365 2366 strcpy(saved_jvm_path, buf); 2367 } 2368 2369 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2370 // no prefix required, not even "_" 2371 } 2372 2373 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2374 // no suffix required 2375 } 2376 2377 //////////////////////////////////////////////////////////////////////////////// 2378 // sun.misc.Signal support 2379 2380 static volatile jint sigint_count = 0; 2381 2382 static void 2383 UserHandler(int sig, void *siginfo, void *context) { 2384 // 4511530 - sem_post is serialized and handled by the manager thread. When 2385 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2386 // don't want to flood the manager thread with sem_post requests. 2387 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) 2388 return; 2389 2390 // Ctrl-C is pressed during error reporting, likely because the error 2391 // handler fails to abort. Let VM die immediately. 2392 if (sig == SIGINT && is_error_reported()) { 2393 os::die(); 2394 } 2395 2396 os::signal_notify(sig); 2397 } 2398 2399 void* os::user_handler() { 2400 return CAST_FROM_FN_PTR(void*, UserHandler); 2401 } 2402 2403 class Semaphore : public StackObj { 2404 public: 2405 Semaphore(); 2406 ~Semaphore(); 2407 void signal(); 2408 void wait(); 2409 bool trywait(); 2410 bool timedwait(unsigned int sec, int nsec); 2411 private: 2412 sem_t _semaphore; 2413 }; 2414 2415 2416 Semaphore::Semaphore() { 2417 sem_init(&_semaphore, 0, 0); 2418 } 2419 2420 Semaphore::~Semaphore() { 2421 sem_destroy(&_semaphore); 2422 } 2423 2424 void Semaphore::signal() { 2425 sem_post(&_semaphore); 2426 } 2427 2428 void Semaphore::wait() { 2429 sem_wait(&_semaphore); 2430 } 2431 2432 bool Semaphore::trywait() { 2433 return sem_trywait(&_semaphore) == 0; 2434 } 2435 2436 bool Semaphore::timedwait(unsigned int sec, int nsec) { 2437 struct timespec ts; 2438 unpackTime(&ts, false, (sec * NANOSECS_PER_SEC) + nsec); 2439 2440 while (1) { 2441 int result = sem_timedwait(&_semaphore, &ts); 2442 if (result == 0) { 2443 return true; 2444 } else if (errno == EINTR) { 2445 continue; 2446 } else if (errno == ETIMEDOUT) { 2447 return false; 2448 } else { 2449 return false; 2450 } 2451 } 2452 } 2453 2454 extern "C" { 2455 typedef void (*sa_handler_t)(int); 2456 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2457 } 2458 2459 void* os::signal(int signal_number, void* handler) { 2460 struct sigaction sigAct, oldSigAct; 2461 2462 sigfillset(&(sigAct.sa_mask)); 2463 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2464 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2465 2466 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2467 // -1 means registration failed 2468 return (void *)-1; 2469 } 2470 2471 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2472 } 2473 2474 void os::signal_raise(int signal_number) { 2475 ::raise(signal_number); 2476 } 2477 2478 /* 2479 * The following code is moved from os.cpp for making this 2480 * code platform specific, which it is by its very nature. 2481 */ 2482 2483 // Will be modified when max signal is changed to be dynamic 2484 int os::sigexitnum_pd() { 2485 return NSIG; 2486 } 2487 2488 // a counter for each possible signal value 2489 static volatile jint pending_signals[NSIG+1] = { 0 }; 2490 2491 // Linux(POSIX) specific hand shaking semaphore. 2492 static sem_t sig_sem; 2493 static Semaphore sr_semaphore; 2494 2495 void os::signal_init_pd() { 2496 // Initialize signal structures 2497 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2498 2499 // Initialize signal semaphore 2500 ::sem_init(&sig_sem, 0, 0); 2501 } 2502 2503 void os::signal_notify(int sig) { 2504 Atomic::inc(&pending_signals[sig]); 2505 ::sem_post(&sig_sem); 2506 } 2507 2508 static int check_pending_signals(bool wait) { 2509 Atomic::store(0, &sigint_count); 2510 for (;;) { 2511 for (int i = 0; i < NSIG + 1; i++) { 2512 jint n = pending_signals[i]; 2513 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2514 return i; 2515 } 2516 } 2517 if (!wait) { 2518 return -1; 2519 } 2520 JavaThread *thread = JavaThread::current(); 2521 ThreadBlockInVM tbivm(thread); 2522 2523 bool threadIsSuspended; 2524 do { 2525 thread->set_suspend_equivalent(); 2526 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2527 ::sem_wait(&sig_sem); 2528 2529 // were we externally suspended while we were waiting? 2530 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2531 if (threadIsSuspended) { 2532 // 2533 // The semaphore has been incremented, but while we were waiting 2534 // another thread suspended us. We don't want to continue running 2535 // while suspended because that would surprise the thread that 2536 // suspended us. 2537 // 2538 ::sem_post(&sig_sem); 2539 2540 thread->java_suspend_self(); 2541 } 2542 } while (threadIsSuspended); 2543 } 2544 } 2545 2546 int os::signal_lookup() { 2547 return check_pending_signals(false); 2548 } 2549 2550 int os::signal_wait() { 2551 return check_pending_signals(true); 2552 } 2553 2554 //////////////////////////////////////////////////////////////////////////////// 2555 // Virtual Memory 2556 2557 int os::vm_page_size() { 2558 // Seems redundant as all get out 2559 assert(os::Linux::page_size() != -1, "must call os::init"); 2560 return os::Linux::page_size(); 2561 } 2562 2563 // Solaris allocates memory by pages. 2564 int os::vm_allocation_granularity() { 2565 assert(os::Linux::page_size() != -1, "must call os::init"); 2566 return os::Linux::page_size(); 2567 } 2568 2569 // Rationale behind this function: 2570 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2571 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2572 // samples for JITted code. Here we create private executable mapping over the code cache 2573 // and then we can use standard (well, almost, as mapping can change) way to provide 2574 // info for the reporting script by storing timestamp and location of symbol 2575 void linux_wrap_code(char* base, size_t size) { 2576 static volatile jint cnt = 0; 2577 2578 if (!UseOprofile) { 2579 return; 2580 } 2581 2582 char buf[PATH_MAX+1]; 2583 int num = Atomic::add(1, &cnt); 2584 2585 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2586 os::get_temp_directory(), os::current_process_id(), num); 2587 unlink(buf); 2588 2589 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2590 2591 if (fd != -1) { 2592 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2593 if (rv != (off_t)-1) { 2594 if (::write(fd, "", 1) == 1) { 2595 mmap(base, size, 2596 PROT_READ|PROT_WRITE|PROT_EXEC, 2597 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2598 } 2599 } 2600 ::close(fd); 2601 unlink(buf); 2602 } 2603 } 2604 2605 // NOTE: Linux kernel does not really reserve the pages for us. 2606 // All it does is to check if there are enough free pages 2607 // left at the time of mmap(). This could be a potential 2608 // problem. 2609 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2610 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2611 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2612 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2613 if (res != (uintptr_t) MAP_FAILED) { 2614 if (UseNUMAInterleaving) { 2615 numa_make_global(addr, size); 2616 } 2617 return true; 2618 } 2619 return false; 2620 } 2621 2622 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2623 #ifndef MAP_HUGETLB 2624 #define MAP_HUGETLB 0x40000 2625 #endif 2626 2627 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2628 #ifndef MADV_HUGEPAGE 2629 #define MADV_HUGEPAGE 14 2630 #endif 2631 2632 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2633 bool exec) { 2634 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) { 2635 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2636 uintptr_t res = 2637 (uintptr_t) ::mmap(addr, size, prot, 2638 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB, 2639 -1, 0); 2640 if (res != (uintptr_t) MAP_FAILED) { 2641 if (UseNUMAInterleaving) { 2642 numa_make_global(addr, size); 2643 } 2644 return true; 2645 } 2646 // Fall through and try to use small pages 2647 } 2648 2649 if (commit_memory(addr, size, exec)) { 2650 realign_memory(addr, size, alignment_hint); 2651 return true; 2652 } 2653 return false; 2654 } 2655 2656 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2657 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) { 2658 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2659 // be supported or the memory may already be backed by huge pages. 2660 ::madvise(addr, bytes, MADV_HUGEPAGE); 2661 } 2662 } 2663 2664 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2665 // This method works by doing an mmap over an existing mmaping and effectively discarding 2666 // the existing pages. However it won't work for SHM-based large pages that cannot be 2667 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2668 // small pages on top of the SHM segment. This method always works for small pages, so we 2669 // allow that in any case. 2670 if (alignment_hint <= (size_t)os::vm_page_size() || !UseSHM) { 2671 commit_memory(addr, bytes, alignment_hint, false); 2672 } 2673 } 2674 2675 void os::numa_make_global(char *addr, size_t bytes) { 2676 Linux::numa_interleave_memory(addr, bytes); 2677 } 2678 2679 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2680 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2681 } 2682 2683 bool os::numa_topology_changed() { return false; } 2684 2685 size_t os::numa_get_groups_num() { 2686 int max_node = Linux::numa_max_node(); 2687 return max_node > 0 ? max_node + 1 : 1; 2688 } 2689 2690 int os::numa_get_group_id() { 2691 int cpu_id = Linux::sched_getcpu(); 2692 if (cpu_id != -1) { 2693 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2694 if (lgrp_id != -1) { 2695 return lgrp_id; 2696 } 2697 } 2698 return 0; 2699 } 2700 2701 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2702 for (size_t i = 0; i < size; i++) { 2703 ids[i] = i; 2704 } 2705 return size; 2706 } 2707 2708 bool os::get_page_info(char *start, page_info* info) { 2709 return false; 2710 } 2711 2712 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) { 2713 return end; 2714 } 2715 2716 2717 int os::Linux::sched_getcpu_syscall(void) { 2718 unsigned int cpu; 2719 int retval = -1; 2720 2721 #if defined(IA32) 2722 # ifndef SYS_getcpu 2723 # define SYS_getcpu 318 2724 # endif 2725 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2726 #elif defined(AMD64) 2727 // Unfortunately we have to bring all these macros here from vsyscall.h 2728 // to be able to compile on old linuxes. 2729 # define __NR_vgetcpu 2 2730 # define VSYSCALL_START (-10UL << 20) 2731 # define VSYSCALL_SIZE 1024 2732 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2733 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2734 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2735 retval = vgetcpu(&cpu, NULL, NULL); 2736 #endif 2737 2738 return (retval == -1) ? retval : cpu; 2739 } 2740 2741 // Something to do with the numa-aware allocator needs these symbols 2742 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2743 extern "C" JNIEXPORT void numa_error(char *where) { } 2744 extern "C" JNIEXPORT int fork1() { return fork(); } 2745 2746 2747 // If we are running with libnuma version > 2, then we should 2748 // be trying to use symbols with versions 1.1 2749 // If we are running with earlier version, which did not have symbol versions, 2750 // we should use the base version. 2751 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2752 void *f = dlvsym(handle, name, "libnuma_1.1"); 2753 if (f == NULL) { 2754 f = dlsym(handle, name); 2755 } 2756 return f; 2757 } 2758 2759 bool os::Linux::libnuma_init() { 2760 // sched_getcpu() should be in libc. 2761 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2762 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2763 2764 // If it's not, try a direct syscall. 2765 if (sched_getcpu() == -1) 2766 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall)); 2767 2768 if (sched_getcpu() != -1) { // Does it work? 2769 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2770 if (handle != NULL) { 2771 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2772 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2773 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2774 libnuma_dlsym(handle, "numa_max_node"))); 2775 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2776 libnuma_dlsym(handle, "numa_available"))); 2777 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2778 libnuma_dlsym(handle, "numa_tonode_memory"))); 2779 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2780 libnuma_dlsym(handle, "numa_interleave_memory"))); 2781 2782 2783 if (numa_available() != -1) { 2784 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2785 // Create a cpu -> node mapping 2786 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2787 rebuild_cpu_to_node_map(); 2788 return true; 2789 } 2790 } 2791 } 2792 return false; 2793 } 2794 2795 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2796 // The table is later used in get_node_by_cpu(). 2797 void os::Linux::rebuild_cpu_to_node_map() { 2798 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2799 // in libnuma (possible values are starting from 16, 2800 // and continuing up with every other power of 2, but less 2801 // than the maximum number of CPUs supported by kernel), and 2802 // is a subject to change (in libnuma version 2 the requirements 2803 // are more reasonable) we'll just hardcode the number they use 2804 // in the library. 2805 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2806 2807 size_t cpu_num = os::active_processor_count(); 2808 size_t cpu_map_size = NCPUS / BitsPerCLong; 2809 size_t cpu_map_valid_size = 2810 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2811 2812 cpu_to_node()->clear(); 2813 cpu_to_node()->at_grow(cpu_num - 1); 2814 size_t node_num = numa_get_groups_num(); 2815 2816 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2817 for (size_t i = 0; i < node_num; i++) { 2818 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2819 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2820 if (cpu_map[j] != 0) { 2821 for (size_t k = 0; k < BitsPerCLong; k++) { 2822 if (cpu_map[j] & (1UL << k)) { 2823 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2824 } 2825 } 2826 } 2827 } 2828 } 2829 } 2830 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal); 2831 } 2832 2833 int os::Linux::get_node_by_cpu(int cpu_id) { 2834 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2835 return cpu_to_node()->at(cpu_id); 2836 } 2837 return -1; 2838 } 2839 2840 GrowableArray<int>* os::Linux::_cpu_to_node; 2841 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2842 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2843 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2844 os::Linux::numa_available_func_t os::Linux::_numa_available; 2845 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2846 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2847 unsigned long* os::Linux::_numa_all_nodes; 2848 2849 bool os::pd_uncommit_memory(char* addr, size_t size) { 2850 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2851 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2852 return res != (uintptr_t) MAP_FAILED; 2853 } 2854 2855 // Linux uses a growable mapping for the stack, and if the mapping for 2856 // the stack guard pages is not removed when we detach a thread the 2857 // stack cannot grow beyond the pages where the stack guard was 2858 // mapped. If at some point later in the process the stack expands to 2859 // that point, the Linux kernel cannot expand the stack any further 2860 // because the guard pages are in the way, and a segfault occurs. 2861 // 2862 // However, it's essential not to split the stack region by unmapping 2863 // a region (leaving a hole) that's already part of the stack mapping, 2864 // so if the stack mapping has already grown beyond the guard pages at 2865 // the time we create them, we have to truncate the stack mapping. 2866 // So, we need to know the extent of the stack mapping when 2867 // create_stack_guard_pages() is called. 2868 2869 // Find the bounds of the stack mapping. Return true for success. 2870 // 2871 // We only need this for stacks that are growable: at the time of 2872 // writing thread stacks don't use growable mappings (i.e. those 2873 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2874 // only applies to the main thread. 2875 2876 static 2877 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) { 2878 2879 char buf[128]; 2880 int fd, sz; 2881 2882 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) { 2883 return false; 2884 } 2885 2886 const char kw[] = "[stack]"; 2887 const int kwlen = sizeof(kw)-1; 2888 2889 // Address part of /proc/self/maps couldn't be more than 128 bytes 2890 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) { 2891 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) { 2892 // Extract addresses 2893 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) { 2894 uintptr_t sp = (uintptr_t) __builtin_frame_address(0); 2895 if (sp >= *bottom && sp <= *top) { 2896 ::close(fd); 2897 return true; 2898 } 2899 } 2900 } 2901 } 2902 2903 ::close(fd); 2904 return false; 2905 } 2906 2907 2908 // If the (growable) stack mapping already extends beyond the point 2909 // where we're going to put our guard pages, truncate the mapping at 2910 // that point by munmap()ping it. This ensures that when we later 2911 // munmap() the guard pages we don't leave a hole in the stack 2912 // mapping. This only affects the main/initial thread, but guard 2913 // against future OS changes 2914 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 2915 uintptr_t stack_extent, stack_base; 2916 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2917 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2918 assert(os::Linux::is_initial_thread(), 2919 "growable stack in non-initial thread"); 2920 if (stack_extent < (uintptr_t)addr) 2921 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent); 2922 } 2923 2924 return os::commit_memory(addr, size); 2925 } 2926 2927 // If this is a growable mapping, remove the guard pages entirely by 2928 // munmap()ping them. If not, just call uncommit_memory(). This only 2929 // affects the main/initial thread, but guard against future OS changes 2930 bool os::remove_stack_guard_pages(char* addr, size_t size) { 2931 uintptr_t stack_extent, stack_base; 2932 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2933 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2934 assert(os::Linux::is_initial_thread(), 2935 "growable stack in non-initial thread"); 2936 2937 return ::munmap(addr, size) == 0; 2938 } 2939 2940 return os::uncommit_memory(addr, size); 2941 } 2942 2943 static address _highest_vm_reserved_address = NULL; 2944 2945 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 2946 // at 'requested_addr'. If there are existing memory mappings at the same 2947 // location, however, they will be overwritten. If 'fixed' is false, 2948 // 'requested_addr' is only treated as a hint, the return value may or 2949 // may not start from the requested address. Unlike Linux mmap(), this 2950 // function returns NULL to indicate failure. 2951 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 2952 char * addr; 2953 int flags; 2954 2955 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 2956 if (fixed) { 2957 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 2958 flags |= MAP_FIXED; 2959 } 2960 2961 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 2962 // touch an uncommitted page. Otherwise, the read/write might 2963 // succeed if we have enough swap space to back the physical page. 2964 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 2965 flags, -1, 0); 2966 2967 if (addr != MAP_FAILED) { 2968 // anon_mmap() should only get called during VM initialization, 2969 // don't need lock (actually we can skip locking even it can be called 2970 // from multiple threads, because _highest_vm_reserved_address is just a 2971 // hint about the upper limit of non-stack memory regions.) 2972 if ((address)addr + bytes > _highest_vm_reserved_address) { 2973 _highest_vm_reserved_address = (address)addr + bytes; 2974 } 2975 } 2976 2977 return addr == MAP_FAILED ? NULL : addr; 2978 } 2979 2980 // Don't update _highest_vm_reserved_address, because there might be memory 2981 // regions above addr + size. If so, releasing a memory region only creates 2982 // a hole in the address space, it doesn't help prevent heap-stack collision. 2983 // 2984 static int anon_munmap(char * addr, size_t size) { 2985 return ::munmap(addr, size) == 0; 2986 } 2987 2988 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 2989 size_t alignment_hint) { 2990 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 2991 } 2992 2993 bool os::pd_release_memory(char* addr, size_t size) { 2994 return anon_munmap(addr, size); 2995 } 2996 2997 static address highest_vm_reserved_address() { 2998 return _highest_vm_reserved_address; 2999 } 3000 3001 static bool linux_mprotect(char* addr, size_t size, int prot) { 3002 // Linux wants the mprotect address argument to be page aligned. 3003 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3004 3005 // According to SUSv3, mprotect() should only be used with mappings 3006 // established by mmap(), and mmap() always maps whole pages. Unaligned 3007 // 'addr' likely indicates problem in the VM (e.g. trying to change 3008 // protection of malloc'ed or statically allocated memory). Check the 3009 // caller if you hit this assert. 3010 assert(addr == bottom, "sanity check"); 3011 3012 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3013 return ::mprotect(bottom, size, prot) == 0; 3014 } 3015 3016 // Set protections specified 3017 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3018 bool is_committed) { 3019 unsigned int p = 0; 3020 switch (prot) { 3021 case MEM_PROT_NONE: p = PROT_NONE; break; 3022 case MEM_PROT_READ: p = PROT_READ; break; 3023 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3024 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3025 default: 3026 ShouldNotReachHere(); 3027 } 3028 // is_committed is unused. 3029 return linux_mprotect(addr, bytes, p); 3030 } 3031 3032 bool os::guard_memory(char* addr, size_t size) { 3033 return linux_mprotect(addr, size, PROT_NONE); 3034 } 3035 3036 bool os::unguard_memory(char* addr, size_t size) { 3037 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3038 } 3039 3040 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3041 bool result = false; 3042 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE, 3043 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3044 -1, 0); 3045 3046 if (p != (void *) -1) { 3047 // We don't know if this really is a huge page or not. 3048 FILE *fp = fopen("/proc/self/maps", "r"); 3049 if (fp) { 3050 while (!feof(fp)) { 3051 char chars[257]; 3052 long x = 0; 3053 if (fgets(chars, sizeof(chars), fp)) { 3054 if (sscanf(chars, "%lx-%*x", &x) == 1 3055 && x == (long)p) { 3056 if (strstr (chars, "hugepage")) { 3057 result = true; 3058 break; 3059 } 3060 } 3061 } 3062 } 3063 fclose(fp); 3064 } 3065 munmap (p, page_size); 3066 if (result) 3067 return true; 3068 } 3069 3070 if (warn) { 3071 warning("HugeTLBFS is not supported by the operating system."); 3072 } 3073 3074 return result; 3075 } 3076 3077 /* 3078 * Set the coredump_filter bits to include largepages in core dump (bit 6) 3079 * 3080 * From the coredump_filter documentation: 3081 * 3082 * - (bit 0) anonymous private memory 3083 * - (bit 1) anonymous shared memory 3084 * - (bit 2) file-backed private memory 3085 * - (bit 3) file-backed shared memory 3086 * - (bit 4) ELF header pages in file-backed private memory areas (it is 3087 * effective only if the bit 2 is cleared) 3088 * - (bit 5) hugetlb private memory 3089 * - (bit 6) hugetlb shared memory 3090 */ 3091 static void set_coredump_filter(void) { 3092 FILE *f; 3093 long cdm; 3094 3095 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3096 return; 3097 } 3098 3099 if (fscanf(f, "%lx", &cdm) != 1) { 3100 fclose(f); 3101 return; 3102 } 3103 3104 rewind(f); 3105 3106 if ((cdm & LARGEPAGES_BIT) == 0) { 3107 cdm |= LARGEPAGES_BIT; 3108 fprintf(f, "%#lx", cdm); 3109 } 3110 3111 fclose(f); 3112 } 3113 3114 // Large page support 3115 3116 static size_t _large_page_size = 0; 3117 3118 void os::large_page_init() { 3119 if (!UseLargePages) { 3120 UseHugeTLBFS = false; 3121 UseSHM = false; 3122 return; 3123 } 3124 3125 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) { 3126 // If UseLargePages is specified on the command line try both methods, 3127 // if it's default, then try only HugeTLBFS. 3128 if (FLAG_IS_DEFAULT(UseLargePages)) { 3129 UseHugeTLBFS = true; 3130 } else { 3131 UseHugeTLBFS = UseSHM = true; 3132 } 3133 } 3134 3135 if (LargePageSizeInBytes) { 3136 _large_page_size = LargePageSizeInBytes; 3137 } else { 3138 // large_page_size on Linux is used to round up heap size. x86 uses either 3139 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3140 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3141 // page as large as 256M. 3142 // 3143 // Here we try to figure out page size by parsing /proc/meminfo and looking 3144 // for a line with the following format: 3145 // Hugepagesize: 2048 kB 3146 // 3147 // If we can't determine the value (e.g. /proc is not mounted, or the text 3148 // format has been changed), we'll use the largest page size supported by 3149 // the processor. 3150 3151 #ifndef ZERO 3152 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3153 ARM_ONLY(2 * M) PPC_ONLY(4 * M); 3154 #endif // ZERO 3155 3156 FILE *fp = fopen("/proc/meminfo", "r"); 3157 if (fp) { 3158 while (!feof(fp)) { 3159 int x = 0; 3160 char buf[16]; 3161 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3162 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3163 _large_page_size = x * K; 3164 break; 3165 } 3166 } else { 3167 // skip to next line 3168 for (;;) { 3169 int ch = fgetc(fp); 3170 if (ch == EOF || ch == (int)'\n') break; 3171 } 3172 } 3173 } 3174 fclose(fp); 3175 } 3176 } 3177 3178 // print a warning if any large page related flag is specified on command line 3179 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3180 3181 const size_t default_page_size = (size_t)Linux::page_size(); 3182 if (_large_page_size > default_page_size) { 3183 _page_sizes[0] = _large_page_size; 3184 _page_sizes[1] = default_page_size; 3185 _page_sizes[2] = 0; 3186 } 3187 UseHugeTLBFS = UseHugeTLBFS && 3188 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size); 3189 3190 if (UseHugeTLBFS) 3191 UseSHM = false; 3192 3193 UseLargePages = UseHugeTLBFS || UseSHM; 3194 3195 set_coredump_filter(); 3196 } 3197 3198 #ifndef SHM_HUGETLB 3199 #define SHM_HUGETLB 04000 3200 #endif 3201 3202 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) { 3203 // "exec" is passed in but not used. Creating the shared image for 3204 // the code cache doesn't have an SHM_X executable permission to check. 3205 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3206 3207 key_t key = IPC_PRIVATE; 3208 char *addr; 3209 3210 bool warn_on_failure = UseLargePages && 3211 (!FLAG_IS_DEFAULT(UseLargePages) || 3212 !FLAG_IS_DEFAULT(LargePageSizeInBytes) 3213 ); 3214 char msg[128]; 3215 3216 // Create a large shared memory region to attach to based on size. 3217 // Currently, size is the total size of the heap 3218 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3219 if (shmid == -1) { 3220 // Possible reasons for shmget failure: 3221 // 1. shmmax is too small for Java heap. 3222 // > check shmmax value: cat /proc/sys/kernel/shmmax 3223 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3224 // 2. not enough large page memory. 3225 // > check available large pages: cat /proc/meminfo 3226 // > increase amount of large pages: 3227 // echo new_value > /proc/sys/vm/nr_hugepages 3228 // Note 1: different Linux may use different name for this property, 3229 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3230 // Note 2: it's possible there's enough physical memory available but 3231 // they are so fragmented after a long run that they can't 3232 // coalesce into large pages. Try to reserve large pages when 3233 // the system is still "fresh". 3234 if (warn_on_failure) { 3235 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3236 warning(msg); 3237 } 3238 return NULL; 3239 } 3240 3241 // attach to the region 3242 addr = (char*)shmat(shmid, req_addr, 0); 3243 int err = errno; 3244 3245 // Remove shmid. If shmat() is successful, the actual shared memory segment 3246 // will be deleted when it's detached by shmdt() or when the process 3247 // terminates. If shmat() is not successful this will remove the shared 3248 // segment immediately. 3249 shmctl(shmid, IPC_RMID, NULL); 3250 3251 if ((intptr_t)addr == -1) { 3252 if (warn_on_failure) { 3253 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3254 warning(msg); 3255 } 3256 return NULL; 3257 } 3258 3259 if ((addr != NULL) && UseNUMAInterleaving) { 3260 numa_make_global(addr, bytes); 3261 } 3262 3263 // The memory is committed 3264 address pc = CALLER_PC; 3265 MemTracker::record_virtual_memory_reserve((address)addr, bytes, pc); 3266 MemTracker::record_virtual_memory_commit((address)addr, bytes, pc); 3267 3268 return addr; 3269 } 3270 3271 bool os::release_memory_special(char* base, size_t bytes) { 3272 // detaching the SHM segment will also delete it, see reserve_memory_special() 3273 int rslt = shmdt(base); 3274 if (rslt == 0) { 3275 MemTracker::record_virtual_memory_uncommit((address)base, bytes); 3276 MemTracker::record_virtual_memory_release((address)base, bytes); 3277 return true; 3278 } else { 3279 return false; 3280 } 3281 } 3282 3283 size_t os::large_page_size() { 3284 return _large_page_size; 3285 } 3286 3287 // HugeTLBFS allows application to commit large page memory on demand; 3288 // with SysV SHM the entire memory region must be allocated as shared 3289 // memory. 3290 bool os::can_commit_large_page_memory() { 3291 return UseHugeTLBFS; 3292 } 3293 3294 bool os::can_execute_large_page_memory() { 3295 return UseHugeTLBFS; 3296 } 3297 3298 // Reserve memory at an arbitrary address, only if that area is 3299 // available (and not reserved for something else). 3300 3301 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3302 const int max_tries = 10; 3303 char* base[max_tries]; 3304 size_t size[max_tries]; 3305 const size_t gap = 0x000000; 3306 3307 // Assert only that the size is a multiple of the page size, since 3308 // that's all that mmap requires, and since that's all we really know 3309 // about at this low abstraction level. If we need higher alignment, 3310 // we can either pass an alignment to this method or verify alignment 3311 // in one of the methods further up the call chain. See bug 5044738. 3312 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3313 3314 // Repeatedly allocate blocks until the block is allocated at the 3315 // right spot. Give up after max_tries. Note that reserve_memory() will 3316 // automatically update _highest_vm_reserved_address if the call is 3317 // successful. The variable tracks the highest memory address every reserved 3318 // by JVM. It is used to detect heap-stack collision if running with 3319 // fixed-stack LinuxThreads. Because here we may attempt to reserve more 3320 // space than needed, it could confuse the collision detecting code. To 3321 // solve the problem, save current _highest_vm_reserved_address and 3322 // calculate the correct value before return. 3323 address old_highest = _highest_vm_reserved_address; 3324 3325 // Linux mmap allows caller to pass an address as hint; give it a try first, 3326 // if kernel honors the hint then we can return immediately. 3327 char * addr = anon_mmap(requested_addr, bytes, false); 3328 if (addr == requested_addr) { 3329 return requested_addr; 3330 } 3331 3332 if (addr != NULL) { 3333 // mmap() is successful but it fails to reserve at the requested address 3334 anon_munmap(addr, bytes); 3335 } 3336 3337 int i; 3338 for (i = 0; i < max_tries; ++i) { 3339 base[i] = reserve_memory(bytes); 3340 3341 if (base[i] != NULL) { 3342 // Is this the block we wanted? 3343 if (base[i] == requested_addr) { 3344 size[i] = bytes; 3345 break; 3346 } 3347 3348 // Does this overlap the block we wanted? Give back the overlapped 3349 // parts and try again. 3350 3351 size_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3352 if (top_overlap >= 0 && top_overlap < bytes) { 3353 unmap_memory(base[i], top_overlap); 3354 base[i] += top_overlap; 3355 size[i] = bytes - top_overlap; 3356 } else { 3357 size_t bottom_overlap = base[i] + bytes - requested_addr; 3358 if (bottom_overlap >= 0 && bottom_overlap < bytes) { 3359 unmap_memory(requested_addr, bottom_overlap); 3360 size[i] = bytes - bottom_overlap; 3361 } else { 3362 size[i] = bytes; 3363 } 3364 } 3365 } 3366 } 3367 3368 // Give back the unused reserved pieces. 3369 3370 for (int j = 0; j < i; ++j) { 3371 if (base[j] != NULL) { 3372 unmap_memory(base[j], size[j]); 3373 } 3374 } 3375 3376 if (i < max_tries) { 3377 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes); 3378 return requested_addr; 3379 } else { 3380 _highest_vm_reserved_address = old_highest; 3381 return NULL; 3382 } 3383 } 3384 3385 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3386 return ::read(fd, buf, nBytes); 3387 } 3388 3389 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation. 3390 // Solaris uses poll(), linux uses park(). 3391 // Poll() is likely a better choice, assuming that Thread.interrupt() 3392 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with 3393 // SIGSEGV, see 4355769. 3394 3395 int os::sleep(Thread* thread, jlong millis, bool interruptible) { 3396 assert(thread == Thread::current(), "thread consistency check"); 3397 3398 ParkEvent * const slp = thread->_SleepEvent ; 3399 slp->reset() ; 3400 OrderAccess::fence() ; 3401 3402 if (interruptible) { 3403 jlong prevtime = javaTimeNanos(); 3404 3405 for (;;) { 3406 if (os::is_interrupted(thread, true)) { 3407 return OS_INTRPT; 3408 } 3409 3410 jlong newtime = javaTimeNanos(); 3411 3412 if (newtime - prevtime < 0) { 3413 // time moving backwards, should only happen if no monotonic clock 3414 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3415 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3416 } else { 3417 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 3418 } 3419 3420 if(millis <= 0) { 3421 return OS_OK; 3422 } 3423 3424 prevtime = newtime; 3425 3426 { 3427 assert(thread->is_Java_thread(), "sanity check"); 3428 JavaThread *jt = (JavaThread *) thread; 3429 ThreadBlockInVM tbivm(jt); 3430 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 3431 3432 jt->set_suspend_equivalent(); 3433 // cleared by handle_special_suspend_equivalent_condition() or 3434 // java_suspend_self() via check_and_wait_while_suspended() 3435 3436 slp->park(millis); 3437 3438 // were we externally suspended while we were waiting? 3439 jt->check_and_wait_while_suspended(); 3440 } 3441 } 3442 } else { 3443 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 3444 jlong prevtime = javaTimeNanos(); 3445 3446 for (;;) { 3447 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 3448 // the 1st iteration ... 3449 jlong newtime = javaTimeNanos(); 3450 3451 if (newtime - prevtime < 0) { 3452 // time moving backwards, should only happen if no monotonic clock 3453 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3454 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3455 } else { 3456 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 3457 } 3458 3459 if(millis <= 0) break ; 3460 3461 prevtime = newtime; 3462 slp->park(millis); 3463 } 3464 return OS_OK ; 3465 } 3466 } 3467 3468 int os::naked_sleep() { 3469 // %% make the sleep time an integer flag. for now use 1 millisec. 3470 return os::sleep(Thread::current(), 1, false); 3471 } 3472 3473 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3474 void os::infinite_sleep() { 3475 while (true) { // sleep forever ... 3476 ::sleep(100); // ... 100 seconds at a time 3477 } 3478 } 3479 3480 // Used to convert frequent JVM_Yield() to nops 3481 bool os::dont_yield() { 3482 return DontYieldALot; 3483 } 3484 3485 void os::yield() { 3486 sched_yield(); 3487 } 3488 3489 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;} 3490 3491 void os::yield_all(int attempts) { 3492 // Yields to all threads, including threads with lower priorities 3493 // Threads on Linux are all with same priority. The Solaris style 3494 // os::yield_all() with nanosleep(1ms) is not necessary. 3495 sched_yield(); 3496 } 3497 3498 // Called from the tight loops to possibly influence time-sharing heuristics 3499 void os::loop_breaker(int attempts) { 3500 os::yield_all(attempts); 3501 } 3502 3503 //////////////////////////////////////////////////////////////////////////////// 3504 // thread priority support 3505 3506 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3507 // only supports dynamic priority, static priority must be zero. For real-time 3508 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3509 // However, for large multi-threaded applications, SCHED_RR is not only slower 3510 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3511 // of 5 runs - Sep 2005). 3512 // 3513 // The following code actually changes the niceness of kernel-thread/LWP. It 3514 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3515 // not the entire user process, and user level threads are 1:1 mapped to kernel 3516 // threads. It has always been the case, but could change in the future. For 3517 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3518 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3519 3520 int os::java_to_os_priority[CriticalPriority + 1] = { 3521 19, // 0 Entry should never be used 3522 3523 4, // 1 MinPriority 3524 3, // 2 3525 2, // 3 3526 3527 1, // 4 3528 0, // 5 NormPriority 3529 -1, // 6 3530 3531 -2, // 7 3532 -3, // 8 3533 -4, // 9 NearMaxPriority 3534 3535 -5, // 10 MaxPriority 3536 3537 -5 // 11 CriticalPriority 3538 }; 3539 3540 static int prio_init() { 3541 if (ThreadPriorityPolicy == 1) { 3542 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3543 // if effective uid is not root. Perhaps, a more elegant way of doing 3544 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3545 if (geteuid() != 0) { 3546 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3547 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3548 } 3549 ThreadPriorityPolicy = 0; 3550 } 3551 } 3552 if (UseCriticalJavaThreadPriority) { 3553 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3554 } 3555 return 0; 3556 } 3557 3558 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3559 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK; 3560 3561 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3562 return (ret == 0) ? OS_OK : OS_ERR; 3563 } 3564 3565 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) { 3566 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) { 3567 *priority_ptr = java_to_os_priority[NormPriority]; 3568 return OS_OK; 3569 } 3570 3571 errno = 0; 3572 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3573 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3574 } 3575 3576 // Hint to the underlying OS that a task switch would not be good. 3577 // Void return because it's a hint and can fail. 3578 void os::hint_no_preempt() {} 3579 3580 //////////////////////////////////////////////////////////////////////////////// 3581 // suspend/resume support 3582 3583 // the low-level signal-based suspend/resume support is a remnant from the 3584 // old VM-suspension that used to be for java-suspension, safepoints etc, 3585 // within hotspot. Now there is a single use-case for this: 3586 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3587 // that runs in the watcher thread. 3588 // The remaining code is greatly simplified from the more general suspension 3589 // code that used to be used. 3590 // 3591 // The protocol is quite simple: 3592 // - suspend: 3593 // - sends a signal to the target thread 3594 // - polls the suspend state of the osthread using a yield loop 3595 // - target thread signal handler (SR_handler) sets suspend state 3596 // and blocks in sigsuspend until continued 3597 // - resume: 3598 // - sets target osthread state to continue 3599 // - sends signal to end the sigsuspend loop in the SR_handler 3600 // 3601 // Note that the SR_lock plays no role in this suspend/resume protocol. 3602 // 3603 3604 static void resume_clear_context(OSThread *osthread) { 3605 osthread->set_ucontext(NULL); 3606 osthread->set_siginfo(NULL); 3607 } 3608 3609 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) { 3610 osthread->set_ucontext(context); 3611 osthread->set_siginfo(siginfo); 3612 } 3613 3614 // 3615 // Handler function invoked when a thread's execution is suspended or 3616 // resumed. We have to be careful that only async-safe functions are 3617 // called here (Note: most pthread functions are not async safe and 3618 // should be avoided.) 3619 // 3620 // Note: sigwait() is a more natural fit than sigsuspend() from an 3621 // interface point of view, but sigwait() prevents the signal hander 3622 // from being run. libpthread would get very confused by not having 3623 // its signal handlers run and prevents sigwait()'s use with the 3624 // mutex granting granting signal. 3625 // 3626 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 3627 // 3628 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3629 // Save and restore errno to avoid confusing native code with EINTR 3630 // after sigsuspend. 3631 int old_errno = errno; 3632 3633 Thread* thread = Thread::current(); 3634 OSThread* osthread = thread->osthread(); 3635 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 3636 3637 os::SuspendResume::State current = osthread->sr.state(); 3638 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 3639 suspend_save_context(osthread, siginfo, context); 3640 3641 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 3642 os::SuspendResume::State state = osthread->sr.suspended(); 3643 if (state == os::SuspendResume::SR_SUSPENDED) { 3644 sigset_t suspend_set; // signals for sigsuspend() 3645 3646 // get current set of blocked signals and unblock resume signal 3647 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3648 sigdelset(&suspend_set, SR_signum); 3649 3650 sr_semaphore.signal(); 3651 // wait here until we are resumed 3652 while (1) { 3653 sigsuspend(&suspend_set); 3654 3655 os::SuspendResume::State result = osthread->sr.running(); 3656 if (result == os::SuspendResume::SR_RUNNING) { 3657 sr_semaphore.signal(); 3658 break; 3659 } 3660 } 3661 3662 } else if (state == os::SuspendResume::SR_RUNNING) { 3663 // request was cancelled, continue 3664 } else { 3665 ShouldNotReachHere(); 3666 } 3667 3668 resume_clear_context(osthread); 3669 } else if (current == os::SuspendResume::SR_RUNNING) { 3670 // request was cancelled, continue 3671 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 3672 // ignore 3673 } else { 3674 // ignore 3675 } 3676 3677 errno = old_errno; 3678 } 3679 3680 3681 static int SR_initialize() { 3682 struct sigaction act; 3683 char *s; 3684 /* Get signal number to use for suspend/resume */ 3685 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3686 int sig = ::strtol(s, 0, 10); 3687 if (sig > 0 || sig < _NSIG) { 3688 SR_signum = sig; 3689 } 3690 } 3691 3692 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 3693 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 3694 3695 sigemptyset(&SR_sigset); 3696 sigaddset(&SR_sigset, SR_signum); 3697 3698 /* Set up signal handler for suspend/resume */ 3699 act.sa_flags = SA_RESTART|SA_SIGINFO; 3700 act.sa_handler = (void (*)(int)) SR_handler; 3701 3702 // SR_signum is blocked by default. 3703 // 4528190 - We also need to block pthread restart signal (32 on all 3704 // supported Linux platforms). Note that LinuxThreads need to block 3705 // this signal for all threads to work properly. So we don't have 3706 // to use hard-coded signal number when setting up the mask. 3707 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 3708 3709 if (sigaction(SR_signum, &act, 0) == -1) { 3710 return -1; 3711 } 3712 3713 // Save signal flag 3714 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 3715 return 0; 3716 } 3717 3718 static int sr_notify(OSThread* osthread) { 3719 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3720 assert_status(status == 0, status, "pthread_kill"); 3721 return status; 3722 } 3723 3724 // "Randomly" selected value for how long we want to spin 3725 // before bailing out on suspending a thread, also how often 3726 // we send a signal to a thread we want to resume 3727 static const int RANDOMLY_LARGE_INTEGER = 1000000; 3728 static const int RANDOMLY_LARGE_INTEGER2 = 100; 3729 3730 // returns true on success and false on error - really an error is fatal 3731 // but this seems the normal response to library errors 3732 static bool do_suspend(OSThread* osthread) { 3733 assert(osthread->sr.is_running(), "thread should be running"); 3734 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 3735 3736 // mark as suspended and send signal 3737 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 3738 // failed to switch, state wasn't running? 3739 ShouldNotReachHere(); 3740 return false; 3741 } 3742 3743 if (sr_notify(osthread) != 0) { 3744 ShouldNotReachHere(); 3745 } 3746 3747 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 3748 while (true) { 3749 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 3750 break; 3751 } else { 3752 // timeout 3753 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 3754 if (cancelled == os::SuspendResume::SR_RUNNING) { 3755 return false; 3756 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 3757 // make sure that we consume the signal on the semaphore as well 3758 sr_semaphore.wait(); 3759 break; 3760 } else { 3761 ShouldNotReachHere(); 3762 return false; 3763 } 3764 } 3765 } 3766 3767 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 3768 return true; 3769 } 3770 3771 static void do_resume(OSThread* osthread) { 3772 assert(osthread->sr.is_suspended(), "thread should be suspended"); 3773 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 3774 3775 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 3776 // failed to switch to WAKEUP_REQUEST 3777 ShouldNotReachHere(); 3778 return; 3779 } 3780 3781 while (true) { 3782 if (sr_notify(osthread) == 0) { 3783 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 3784 if (osthread->sr.is_running()) { 3785 return; 3786 } 3787 } 3788 } else { 3789 ShouldNotReachHere(); 3790 } 3791 } 3792 3793 guarantee(osthread->sr.is_running(), "Must be running!"); 3794 } 3795 3796 //////////////////////////////////////////////////////////////////////////////// 3797 // interrupt support 3798 3799 void os::interrupt(Thread* thread) { 3800 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3801 "possibility of dangling Thread pointer"); 3802 3803 OSThread* osthread = thread->osthread(); 3804 3805 if (!osthread->interrupted()) { 3806 osthread->set_interrupted(true); 3807 // More than one thread can get here with the same value of osthread, 3808 // resulting in multiple notifications. We do, however, want the store 3809 // to interrupted() to be visible to other threads before we execute unpark(). 3810 OrderAccess::fence(); 3811 ParkEvent * const slp = thread->_SleepEvent ; 3812 if (slp != NULL) slp->unpark() ; 3813 } 3814 3815 // For JSR166. Unpark even if interrupt status already was set 3816 if (thread->is_Java_thread()) 3817 ((JavaThread*)thread)->parker()->unpark(); 3818 3819 ParkEvent * ev = thread->_ParkEvent ; 3820 if (ev != NULL) ev->unpark() ; 3821 3822 } 3823 3824 bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 3825 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3826 "possibility of dangling Thread pointer"); 3827 3828 OSThread* osthread = thread->osthread(); 3829 3830 bool interrupted = osthread->interrupted(); 3831 3832 if (interrupted && clear_interrupted) { 3833 osthread->set_interrupted(false); 3834 // consider thread->_SleepEvent->reset() ... optional optimization 3835 } 3836 3837 return interrupted; 3838 } 3839 3840 /////////////////////////////////////////////////////////////////////////////////// 3841 // signal handling (except suspend/resume) 3842 3843 // This routine may be used by user applications as a "hook" to catch signals. 3844 // The user-defined signal handler must pass unrecognized signals to this 3845 // routine, and if it returns true (non-zero), then the signal handler must 3846 // return immediately. If the flag "abort_if_unrecognized" is true, then this 3847 // routine will never retun false (zero), but instead will execute a VM panic 3848 // routine kill the process. 3849 // 3850 // If this routine returns false, it is OK to call it again. This allows 3851 // the user-defined signal handler to perform checks either before or after 3852 // the VM performs its own checks. Naturally, the user code would be making 3853 // a serious error if it tried to handle an exception (such as a null check 3854 // or breakpoint) that the VM was generating for its own correct operation. 3855 // 3856 // This routine may recognize any of the following kinds of signals: 3857 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 3858 // It should be consulted by handlers for any of those signals. 3859 // 3860 // The caller of this routine must pass in the three arguments supplied 3861 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 3862 // field of the structure passed to sigaction(). This routine assumes that 3863 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 3864 // 3865 // Note that the VM will print warnings if it detects conflicting signal 3866 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 3867 // 3868 extern "C" JNIEXPORT int 3869 JVM_handle_linux_signal(int signo, siginfo_t* siginfo, 3870 void* ucontext, int abort_if_unrecognized); 3871 3872 void signalHandler(int sig, siginfo_t* info, void* uc) { 3873 assert(info != NULL && uc != NULL, "it must be old kernel"); 3874 int orig_errno = errno; // Preserve errno value over signal handler. 3875 JVM_handle_linux_signal(sig, info, uc, true); 3876 errno = orig_errno; 3877 } 3878 3879 3880 // This boolean allows users to forward their own non-matching signals 3881 // to JVM_handle_linux_signal, harmlessly. 3882 bool os::Linux::signal_handlers_are_installed = false; 3883 3884 // For signal-chaining 3885 struct sigaction os::Linux::sigact[MAXSIGNUM]; 3886 unsigned int os::Linux::sigs = 0; 3887 bool os::Linux::libjsig_is_loaded = false; 3888 typedef struct sigaction *(*get_signal_t)(int); 3889 get_signal_t os::Linux::get_signal_action = NULL; 3890 3891 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 3892 struct sigaction *actp = NULL; 3893 3894 if (libjsig_is_loaded) { 3895 // Retrieve the old signal handler from libjsig 3896 actp = (*get_signal_action)(sig); 3897 } 3898 if (actp == NULL) { 3899 // Retrieve the preinstalled signal handler from jvm 3900 actp = get_preinstalled_handler(sig); 3901 } 3902 3903 return actp; 3904 } 3905 3906 static bool call_chained_handler(struct sigaction *actp, int sig, 3907 siginfo_t *siginfo, void *context) { 3908 // Call the old signal handler 3909 if (actp->sa_handler == SIG_DFL) { 3910 // It's more reasonable to let jvm treat it as an unexpected exception 3911 // instead of taking the default action. 3912 return false; 3913 } else if (actp->sa_handler != SIG_IGN) { 3914 if ((actp->sa_flags & SA_NODEFER) == 0) { 3915 // automaticlly block the signal 3916 sigaddset(&(actp->sa_mask), sig); 3917 } 3918 3919 sa_handler_t hand; 3920 sa_sigaction_t sa; 3921 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 3922 // retrieve the chained handler 3923 if (siginfo_flag_set) { 3924 sa = actp->sa_sigaction; 3925 } else { 3926 hand = actp->sa_handler; 3927 } 3928 3929 if ((actp->sa_flags & SA_RESETHAND) != 0) { 3930 actp->sa_handler = SIG_DFL; 3931 } 3932 3933 // try to honor the signal mask 3934 sigset_t oset; 3935 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 3936 3937 // call into the chained handler 3938 if (siginfo_flag_set) { 3939 (*sa)(sig, siginfo, context); 3940 } else { 3941 (*hand)(sig); 3942 } 3943 3944 // restore the signal mask 3945 pthread_sigmask(SIG_SETMASK, &oset, 0); 3946 } 3947 // Tell jvm's signal handler the signal is taken care of. 3948 return true; 3949 } 3950 3951 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 3952 bool chained = false; 3953 // signal-chaining 3954 if (UseSignalChaining) { 3955 struct sigaction *actp = get_chained_signal_action(sig); 3956 if (actp != NULL) { 3957 chained = call_chained_handler(actp, sig, siginfo, context); 3958 } 3959 } 3960 return chained; 3961 } 3962 3963 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 3964 if ((( (unsigned int)1 << sig ) & sigs) != 0) { 3965 return &sigact[sig]; 3966 } 3967 return NULL; 3968 } 3969 3970 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 3971 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3972 sigact[sig] = oldAct; 3973 sigs |= (unsigned int)1 << sig; 3974 } 3975 3976 // for diagnostic 3977 int os::Linux::sigflags[MAXSIGNUM]; 3978 3979 int os::Linux::get_our_sigflags(int sig) { 3980 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3981 return sigflags[sig]; 3982 } 3983 3984 void os::Linux::set_our_sigflags(int sig, int flags) { 3985 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3986 sigflags[sig] = flags; 3987 } 3988 3989 void os::Linux::set_signal_handler(int sig, bool set_installed) { 3990 // Check for overwrite. 3991 struct sigaction oldAct; 3992 sigaction(sig, (struct sigaction*)NULL, &oldAct); 3993 3994 void* oldhand = oldAct.sa_sigaction 3995 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3996 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3997 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 3998 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 3999 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4000 if (AllowUserSignalHandlers || !set_installed) { 4001 // Do not overwrite; user takes responsibility to forward to us. 4002 return; 4003 } else if (UseSignalChaining) { 4004 // save the old handler in jvm 4005 save_preinstalled_handler(sig, oldAct); 4006 // libjsig also interposes the sigaction() call below and saves the 4007 // old sigaction on it own. 4008 } else { 4009 fatal(err_msg("Encountered unexpected pre-existing sigaction handler " 4010 "%#lx for signal %d.", (long)oldhand, sig)); 4011 } 4012 } 4013 4014 struct sigaction sigAct; 4015 sigfillset(&(sigAct.sa_mask)); 4016 sigAct.sa_handler = SIG_DFL; 4017 if (!set_installed) { 4018 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4019 } else { 4020 sigAct.sa_sigaction = signalHandler; 4021 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4022 } 4023 // Save flags, which are set by ours 4024 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4025 sigflags[sig] = sigAct.sa_flags; 4026 4027 int ret = sigaction(sig, &sigAct, &oldAct); 4028 assert(ret == 0, "check"); 4029 4030 void* oldhand2 = oldAct.sa_sigaction 4031 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4032 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4033 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4034 } 4035 4036 // install signal handlers for signals that HotSpot needs to 4037 // handle in order to support Java-level exception handling. 4038 4039 void os::Linux::install_signal_handlers() { 4040 if (!signal_handlers_are_installed) { 4041 signal_handlers_are_installed = true; 4042 4043 // signal-chaining 4044 typedef void (*signal_setting_t)(); 4045 signal_setting_t begin_signal_setting = NULL; 4046 signal_setting_t end_signal_setting = NULL; 4047 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4048 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4049 if (begin_signal_setting != NULL) { 4050 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4051 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4052 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4053 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4054 libjsig_is_loaded = true; 4055 assert(UseSignalChaining, "should enable signal-chaining"); 4056 } 4057 if (libjsig_is_loaded) { 4058 // Tell libjsig jvm is setting signal handlers 4059 (*begin_signal_setting)(); 4060 } 4061 4062 set_signal_handler(SIGSEGV, true); 4063 set_signal_handler(SIGPIPE, true); 4064 set_signal_handler(SIGBUS, true); 4065 set_signal_handler(SIGILL, true); 4066 set_signal_handler(SIGFPE, true); 4067 set_signal_handler(SIGXFSZ, true); 4068 4069 if (libjsig_is_loaded) { 4070 // Tell libjsig jvm finishes setting signal handlers 4071 (*end_signal_setting)(); 4072 } 4073 4074 // We don't activate signal checker if libjsig is in place, we trust ourselves 4075 // and if UserSignalHandler is installed all bets are off. 4076 // Log that signal checking is off only if -verbose:jni is specified. 4077 if (CheckJNICalls) { 4078 if (libjsig_is_loaded) { 4079 if (PrintJNIResolving) { 4080 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4081 } 4082 check_signals = false; 4083 } 4084 if (AllowUserSignalHandlers) { 4085 if (PrintJNIResolving) { 4086 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4087 } 4088 check_signals = false; 4089 } 4090 } 4091 } 4092 } 4093 4094 // This is the fastest way to get thread cpu time on Linux. 4095 // Returns cpu time (user+sys) for any thread, not only for current. 4096 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4097 // It might work on 2.6.10+ with a special kernel/glibc patch. 4098 // For reference, please, see IEEE Std 1003.1-2004: 4099 // http://www.unix.org/single_unix_specification 4100 4101 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4102 struct timespec tp; 4103 int rc = os::Linux::clock_gettime(clockid, &tp); 4104 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4105 4106 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4107 } 4108 4109 ///// 4110 // glibc on Linux platform uses non-documented flag 4111 // to indicate, that some special sort of signal 4112 // trampoline is used. 4113 // We will never set this flag, and we should 4114 // ignore this flag in our diagnostic 4115 #ifdef SIGNIFICANT_SIGNAL_MASK 4116 #undef SIGNIFICANT_SIGNAL_MASK 4117 #endif 4118 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4119 4120 static const char* get_signal_handler_name(address handler, 4121 char* buf, int buflen) { 4122 int offset; 4123 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4124 if (found) { 4125 // skip directory names 4126 const char *p1, *p2; 4127 p1 = buf; 4128 size_t len = strlen(os::file_separator()); 4129 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4130 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4131 } else { 4132 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4133 } 4134 return buf; 4135 } 4136 4137 static void print_signal_handler(outputStream* st, int sig, 4138 char* buf, size_t buflen) { 4139 struct sigaction sa; 4140 4141 sigaction(sig, NULL, &sa); 4142 4143 // See comment for SIGNIFICANT_SIGNAL_MASK define 4144 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4145 4146 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4147 4148 address handler = (sa.sa_flags & SA_SIGINFO) 4149 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4150 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4151 4152 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4153 st->print("SIG_DFL"); 4154 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4155 st->print("SIG_IGN"); 4156 } else { 4157 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4158 } 4159 4160 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask); 4161 4162 address rh = VMError::get_resetted_sighandler(sig); 4163 // May be, handler was resetted by VMError? 4164 if(rh != NULL) { 4165 handler = rh; 4166 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4167 } 4168 4169 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags); 4170 4171 // Check: is it our handler? 4172 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4173 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4174 // It is our signal handler 4175 // check for flags, reset system-used one! 4176 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4177 st->print( 4178 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4179 os::Linux::get_our_sigflags(sig)); 4180 } 4181 } 4182 st->cr(); 4183 } 4184 4185 4186 #define DO_SIGNAL_CHECK(sig) \ 4187 if (!sigismember(&check_signal_done, sig)) \ 4188 os::Linux::check_signal_handler(sig) 4189 4190 // This method is a periodic task to check for misbehaving JNI applications 4191 // under CheckJNI, we can add any periodic checks here 4192 4193 void os::run_periodic_checks() { 4194 4195 if (check_signals == false) return; 4196 4197 // SEGV and BUS if overridden could potentially prevent 4198 // generation of hs*.log in the event of a crash, debugging 4199 // such a case can be very challenging, so we absolutely 4200 // check the following for a good measure: 4201 DO_SIGNAL_CHECK(SIGSEGV); 4202 DO_SIGNAL_CHECK(SIGILL); 4203 DO_SIGNAL_CHECK(SIGFPE); 4204 DO_SIGNAL_CHECK(SIGBUS); 4205 DO_SIGNAL_CHECK(SIGPIPE); 4206 DO_SIGNAL_CHECK(SIGXFSZ); 4207 4208 4209 // ReduceSignalUsage allows the user to override these handlers 4210 // see comments at the very top and jvm_solaris.h 4211 if (!ReduceSignalUsage) { 4212 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4213 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4214 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4215 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4216 } 4217 4218 DO_SIGNAL_CHECK(SR_signum); 4219 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 4220 } 4221 4222 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4223 4224 static os_sigaction_t os_sigaction = NULL; 4225 4226 void os::Linux::check_signal_handler(int sig) { 4227 char buf[O_BUFLEN]; 4228 address jvmHandler = NULL; 4229 4230 4231 struct sigaction act; 4232 if (os_sigaction == NULL) { 4233 // only trust the default sigaction, in case it has been interposed 4234 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4235 if (os_sigaction == NULL) return; 4236 } 4237 4238 os_sigaction(sig, (struct sigaction*)NULL, &act); 4239 4240 4241 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4242 4243 address thisHandler = (act.sa_flags & SA_SIGINFO) 4244 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4245 : CAST_FROM_FN_PTR(address, act.sa_handler) ; 4246 4247 4248 switch(sig) { 4249 case SIGSEGV: 4250 case SIGBUS: 4251 case SIGFPE: 4252 case SIGPIPE: 4253 case SIGILL: 4254 case SIGXFSZ: 4255 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4256 break; 4257 4258 case SHUTDOWN1_SIGNAL: 4259 case SHUTDOWN2_SIGNAL: 4260 case SHUTDOWN3_SIGNAL: 4261 case BREAK_SIGNAL: 4262 jvmHandler = (address)user_handler(); 4263 break; 4264 4265 case INTERRUPT_SIGNAL: 4266 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 4267 break; 4268 4269 default: 4270 if (sig == SR_signum) { 4271 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4272 } else { 4273 return; 4274 } 4275 break; 4276 } 4277 4278 if (thisHandler != jvmHandler) { 4279 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4280 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4281 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4282 // No need to check this sig any longer 4283 sigaddset(&check_signal_done, sig); 4284 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4285 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4286 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 4287 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 4288 // No need to check this sig any longer 4289 sigaddset(&check_signal_done, sig); 4290 } 4291 4292 // Dump all the signal 4293 if (sigismember(&check_signal_done, sig)) { 4294 print_signal_handlers(tty, buf, O_BUFLEN); 4295 } 4296 } 4297 4298 extern void report_error(char* file_name, int line_no, char* title, char* format, ...); 4299 4300 extern bool signal_name(int signo, char* buf, size_t len); 4301 4302 const char* os::exception_name(int exception_code, char* buf, size_t size) { 4303 if (0 < exception_code && exception_code <= SIGRTMAX) { 4304 // signal 4305 if (!signal_name(exception_code, buf, size)) { 4306 jio_snprintf(buf, size, "SIG%d", exception_code); 4307 } 4308 return buf; 4309 } else { 4310 return NULL; 4311 } 4312 } 4313 4314 // this is called _before_ the most of global arguments have been parsed 4315 void os::init(void) { 4316 char dummy; /* used to get a guess on initial stack address */ 4317 // first_hrtime = gethrtime(); 4318 4319 // With LinuxThreads the JavaMain thread pid (primordial thread) 4320 // is different than the pid of the java launcher thread. 4321 // So, on Linux, the launcher thread pid is passed to the VM 4322 // via the sun.java.launcher.pid property. 4323 // Use this property instead of getpid() if it was correctly passed. 4324 // See bug 6351349. 4325 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid(); 4326 4327 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid(); 4328 4329 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4330 4331 init_random(1234567); 4332 4333 ThreadCritical::initialize(); 4334 4335 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4336 if (Linux::page_size() == -1) { 4337 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)", 4338 strerror(errno))); 4339 } 4340 init_page_sizes((size_t) Linux::page_size()); 4341 4342 Linux::initialize_system_info(); 4343 4344 // main_thread points to the aboriginal thread 4345 Linux::_main_thread = pthread_self(); 4346 4347 Linux::clock_init(); 4348 initial_time_count = os::elapsed_counter(); 4349 pthread_mutex_init(&dl_mutex, NULL); 4350 4351 // If the pagesize of the VM is greater than 8K determine the appropriate 4352 // number of initial guard pages. The user can change this with the 4353 // command line arguments, if needed. 4354 if (vm_page_size() > (int)Linux::vm_default_page_size()) { 4355 StackYellowPages = 1; 4356 StackRedPages = 1; 4357 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size(); 4358 } 4359 } 4360 4361 // To install functions for atexit system call 4362 extern "C" { 4363 static void perfMemory_exit_helper() { 4364 perfMemory_exit(); 4365 } 4366 } 4367 4368 // this is called _after_ the global arguments have been parsed 4369 jint os::init_2(void) 4370 { 4371 Linux::fast_thread_clock_init(); 4372 4373 // Allocate a single page and mark it as readable for safepoint polling 4374 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4375 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" ); 4376 4377 os::set_polling_page( polling_page ); 4378 4379 #ifndef PRODUCT 4380 if(Verbose && PrintMiscellaneous) 4381 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page); 4382 #endif 4383 4384 if (!UseMembar) { 4385 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4386 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page"); 4387 os::set_memory_serialize_page( mem_serialize_page ); 4388 4389 #ifndef PRODUCT 4390 if(Verbose && PrintMiscellaneous) 4391 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page); 4392 #endif 4393 } 4394 4395 os::large_page_init(); 4396 4397 // initialize suspend/resume support - must do this before signal_sets_init() 4398 if (SR_initialize() != 0) { 4399 perror("SR_initialize failed"); 4400 return JNI_ERR; 4401 } 4402 4403 Linux::signal_sets_init(); 4404 Linux::install_signal_handlers(); 4405 4406 // Check minimum allowable stack size for thread creation and to initialize 4407 // the java system classes, including StackOverflowError - depends on page 4408 // size. Add a page for compiler2 recursion in main thread. 4409 // Add in 2*BytesPerWord times page size to account for VM stack during 4410 // class initialization depending on 32 or 64 bit VM. 4411 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4412 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() + 4413 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size()); 4414 4415 size_t threadStackSizeInBytes = ThreadStackSize * K; 4416 if (threadStackSizeInBytes != 0 && 4417 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4418 tty->print_cr("\nThe stack size specified is too small, " 4419 "Specify at least %dk", 4420 os::Linux::min_stack_allowed/ K); 4421 return JNI_ERR; 4422 } 4423 4424 // Make the stack size a multiple of the page size so that 4425 // the yellow/red zones can be guarded. 4426 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4427 vm_page_size())); 4428 4429 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4430 4431 Linux::libpthread_init(); 4432 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4433 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n", 4434 Linux::glibc_version(), Linux::libpthread_version(), 4435 Linux::is_floating_stack() ? "floating stack" : "fixed stack"); 4436 } 4437 4438 if (UseNUMA) { 4439 if (!Linux::libnuma_init()) { 4440 UseNUMA = false; 4441 } else { 4442 if ((Linux::numa_max_node() < 1)) { 4443 // There's only one node(they start from 0), disable NUMA. 4444 UseNUMA = false; 4445 } 4446 } 4447 // With SHM large pages we cannot uncommit a page, so there's not way 4448 // we can make the adaptive lgrp chunk resizing work. If the user specified 4449 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and 4450 // disable adaptive resizing. 4451 if (UseNUMA && UseLargePages && UseSHM) { 4452 if (!FLAG_IS_DEFAULT(UseNUMA)) { 4453 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) { 4454 UseLargePages = false; 4455 } else { 4456 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing"); 4457 UseAdaptiveSizePolicy = false; 4458 UseAdaptiveNUMAChunkSizing = false; 4459 } 4460 } else { 4461 UseNUMA = false; 4462 } 4463 } 4464 if (!UseNUMA && ForceNUMA) { 4465 UseNUMA = true; 4466 } 4467 } 4468 4469 if (MaxFDLimit) { 4470 // set the number of file descriptors to max. print out error 4471 // if getrlimit/setrlimit fails but continue regardless. 4472 struct rlimit nbr_files; 4473 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4474 if (status != 0) { 4475 if (PrintMiscellaneous && (Verbose || WizardMode)) 4476 perror("os::init_2 getrlimit failed"); 4477 } else { 4478 nbr_files.rlim_cur = nbr_files.rlim_max; 4479 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4480 if (status != 0) { 4481 if (PrintMiscellaneous && (Verbose || WizardMode)) 4482 perror("os::init_2 setrlimit failed"); 4483 } 4484 } 4485 } 4486 4487 // Initialize lock used to serialize thread creation (see os::create_thread) 4488 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4489 4490 // at-exit methods are called in the reverse order of their registration. 4491 // atexit functions are called on return from main or as a result of a 4492 // call to exit(3C). There can be only 32 of these functions registered 4493 // and atexit() does not set errno. 4494 4495 if (PerfAllowAtExitRegistration) { 4496 // only register atexit functions if PerfAllowAtExitRegistration is set. 4497 // atexit functions can be delayed until process exit time, which 4498 // can be problematic for embedded VM situations. Embedded VMs should 4499 // call DestroyJavaVM() to assure that VM resources are released. 4500 4501 // note: perfMemory_exit_helper atexit function may be removed in 4502 // the future if the appropriate cleanup code can be added to the 4503 // VM_Exit VMOperation's doit method. 4504 if (atexit(perfMemory_exit_helper) != 0) { 4505 warning("os::init2 atexit(perfMemory_exit_helper) failed"); 4506 } 4507 } 4508 4509 // initialize thread priority policy 4510 prio_init(); 4511 4512 return JNI_OK; 4513 } 4514 4515 // this is called at the end of vm_initialization 4516 void os::init_3(void) 4517 { 4518 #ifdef JAVASE_EMBEDDED 4519 // Start the MemNotifyThread 4520 if (LowMemoryProtection) { 4521 MemNotifyThread::start(); 4522 } 4523 return; 4524 #endif 4525 } 4526 4527 // Mark the polling page as unreadable 4528 void os::make_polling_page_unreadable(void) { 4529 if( !guard_memory((char*)_polling_page, Linux::page_size()) ) 4530 fatal("Could not disable polling page"); 4531 }; 4532 4533 // Mark the polling page as readable 4534 void os::make_polling_page_readable(void) { 4535 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4536 fatal("Could not enable polling page"); 4537 } 4538 }; 4539 4540 int os::active_processor_count() { 4541 // Linux doesn't yet have a (official) notion of processor sets, 4542 // so just return the number of online processors. 4543 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4544 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4545 return online_cpus; 4546 } 4547 4548 void os::set_native_thread_name(const char *name) { 4549 // Not yet implemented. 4550 return; 4551 } 4552 4553 bool os::distribute_processes(uint length, uint* distribution) { 4554 // Not yet implemented. 4555 return false; 4556 } 4557 4558 bool os::bind_to_processor(uint processor_id) { 4559 // Not yet implemented. 4560 return false; 4561 } 4562 4563 /// 4564 4565 void os::SuspendedThreadTask::internal_do_task() { 4566 if (do_suspend(_thread->osthread())) { 4567 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 4568 do_task(context); 4569 do_resume(_thread->osthread()); 4570 } 4571 } 4572 4573 class PcFetcher : public os::SuspendedThreadTask { 4574 public: 4575 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 4576 ExtendedPC result(); 4577 protected: 4578 void do_task(const os::SuspendedThreadTaskContext& context); 4579 private: 4580 ExtendedPC _epc; 4581 }; 4582 4583 ExtendedPC PcFetcher::result() { 4584 guarantee(is_done(), "task is not done yet."); 4585 return _epc; 4586 } 4587 4588 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 4589 Thread* thread = context.thread(); 4590 OSThread* osthread = thread->osthread(); 4591 if (osthread->ucontext() != NULL) { 4592 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext()); 4593 } else { 4594 // NULL context is unexpected, double-check this is the VMThread 4595 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4596 } 4597 } 4598 4599 // Suspends the target using the signal mechanism and then grabs the PC before 4600 // resuming the target. Used by the flat-profiler only 4601 ExtendedPC os::get_thread_pc(Thread* thread) { 4602 // Make sure that it is called by the watcher for the VMThread 4603 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4604 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4605 4606 PcFetcher fetcher(thread); 4607 fetcher.run(); 4608 return fetcher.result(); 4609 } 4610 4611 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime) 4612 { 4613 if (is_NPTL()) { 4614 return pthread_cond_timedwait(_cond, _mutex, _abstime); 4615 } else { 4616 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control 4617 // word back to default 64bit precision if condvar is signaled. Java 4618 // wants 53bit precision. Save and restore current value. 4619 int fpu = get_fpu_control_word(); 4620 int status = pthread_cond_timedwait(_cond, _mutex, _abstime); 4621 set_fpu_control_word(fpu); 4622 return status; 4623 } 4624 } 4625 4626 //////////////////////////////////////////////////////////////////////////////// 4627 // debug support 4628 4629 bool os::find(address addr, outputStream* st) { 4630 Dl_info dlinfo; 4631 memset(&dlinfo, 0, sizeof(dlinfo)); 4632 if (dladdr(addr, &dlinfo)) { 4633 st->print(PTR_FORMAT ": ", addr); 4634 if (dlinfo.dli_sname != NULL) { 4635 st->print("%s+%#x", dlinfo.dli_sname, 4636 addr - (intptr_t)dlinfo.dli_saddr); 4637 } else if (dlinfo.dli_fname) { 4638 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 4639 } else { 4640 st->print("<absolute address>"); 4641 } 4642 if (dlinfo.dli_fname) { 4643 st->print(" in %s", dlinfo.dli_fname); 4644 } 4645 if (dlinfo.dli_fbase) { 4646 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 4647 } 4648 st->cr(); 4649 4650 if (Verbose) { 4651 // decode some bytes around the PC 4652 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 4653 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 4654 address lowest = (address) dlinfo.dli_sname; 4655 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4656 if (begin < lowest) begin = lowest; 4657 Dl_info dlinfo2; 4658 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr 4659 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) 4660 end = (address) dlinfo2.dli_saddr; 4661 Disassembler::decode(begin, end, st); 4662 } 4663 return true; 4664 } 4665 return false; 4666 } 4667 4668 //////////////////////////////////////////////////////////////////////////////// 4669 // misc 4670 4671 // This does not do anything on Linux. This is basically a hook for being 4672 // able to use structured exception handling (thread-local exception filters) 4673 // on, e.g., Win32. 4674 void 4675 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 4676 JavaCallArguments* args, Thread* thread) { 4677 f(value, method, args, thread); 4678 } 4679 4680 void os::print_statistics() { 4681 } 4682 4683 int os::message_box(const char* title, const char* message) { 4684 int i; 4685 fdStream err(defaultStream::error_fd()); 4686 for (i = 0; i < 78; i++) err.print_raw("="); 4687 err.cr(); 4688 err.print_raw_cr(title); 4689 for (i = 0; i < 78; i++) err.print_raw("-"); 4690 err.cr(); 4691 err.print_raw_cr(message); 4692 for (i = 0; i < 78; i++) err.print_raw("="); 4693 err.cr(); 4694 4695 char buf[16]; 4696 // Prevent process from exiting upon "read error" without consuming all CPU 4697 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4698 4699 return buf[0] == 'y' || buf[0] == 'Y'; 4700 } 4701 4702 int os::stat(const char *path, struct stat *sbuf) { 4703 char pathbuf[MAX_PATH]; 4704 if (strlen(path) > MAX_PATH - 1) { 4705 errno = ENAMETOOLONG; 4706 return -1; 4707 } 4708 os::native_path(strcpy(pathbuf, path)); 4709 return ::stat(pathbuf, sbuf); 4710 } 4711 4712 bool os::check_heap(bool force) { 4713 return true; 4714 } 4715 4716 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) { 4717 return ::vsnprintf(buf, count, format, args); 4718 } 4719 4720 // Is a (classpath) directory empty? 4721 bool os::dir_is_empty(const char* path) { 4722 DIR *dir = NULL; 4723 struct dirent *ptr; 4724 4725 dir = opendir(path); 4726 if (dir == NULL) return true; 4727 4728 /* Scan the directory */ 4729 bool result = true; 4730 char buf[sizeof(struct dirent) + MAX_PATH]; 4731 while (result && (ptr = ::readdir(dir)) != NULL) { 4732 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 4733 result = false; 4734 } 4735 } 4736 closedir(dir); 4737 return result; 4738 } 4739 4740 // This code originates from JDK's sysOpen and open64_w 4741 // from src/solaris/hpi/src/system_md.c 4742 4743 #ifndef O_DELETE 4744 #define O_DELETE 0x10000 4745 #endif 4746 4747 // Open a file. Unlink the file immediately after open returns 4748 // if the specified oflag has the O_DELETE flag set. 4749 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c 4750 4751 int os::open(const char *path, int oflag, int mode) { 4752 4753 if (strlen(path) > MAX_PATH - 1) { 4754 errno = ENAMETOOLONG; 4755 return -1; 4756 } 4757 int fd; 4758 int o_delete = (oflag & O_DELETE); 4759 oflag = oflag & ~O_DELETE; 4760 4761 fd = ::open64(path, oflag, mode); 4762 if (fd == -1) return -1; 4763 4764 //If the open succeeded, the file might still be a directory 4765 { 4766 struct stat64 buf64; 4767 int ret = ::fstat64(fd, &buf64); 4768 int st_mode = buf64.st_mode; 4769 4770 if (ret != -1) { 4771 if ((st_mode & S_IFMT) == S_IFDIR) { 4772 errno = EISDIR; 4773 ::close(fd); 4774 return -1; 4775 } 4776 } else { 4777 ::close(fd); 4778 return -1; 4779 } 4780 } 4781 4782 /* 4783 * All file descriptors that are opened in the JVM and not 4784 * specifically destined for a subprocess should have the 4785 * close-on-exec flag set. If we don't set it, then careless 3rd 4786 * party native code might fork and exec without closing all 4787 * appropriate file descriptors (e.g. as we do in closeDescriptors in 4788 * UNIXProcess.c), and this in turn might: 4789 * 4790 * - cause end-of-file to fail to be detected on some file 4791 * descriptors, resulting in mysterious hangs, or 4792 * 4793 * - might cause an fopen in the subprocess to fail on a system 4794 * suffering from bug 1085341. 4795 * 4796 * (Yes, the default setting of the close-on-exec flag is a Unix 4797 * design flaw) 4798 * 4799 * See: 4800 * 1085341: 32-bit stdio routines should support file descriptors >255 4801 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed 4802 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 4803 */ 4804 #ifdef FD_CLOEXEC 4805 { 4806 int flags = ::fcntl(fd, F_GETFD); 4807 if (flags != -1) 4808 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 4809 } 4810 #endif 4811 4812 if (o_delete != 0) { 4813 ::unlink(path); 4814 } 4815 return fd; 4816 } 4817 4818 4819 // create binary file, rewriting existing file if required 4820 int os::create_binary_file(const char* path, bool rewrite_existing) { 4821 int oflags = O_WRONLY | O_CREAT; 4822 if (!rewrite_existing) { 4823 oflags |= O_EXCL; 4824 } 4825 return ::open64(path, oflags, S_IREAD | S_IWRITE); 4826 } 4827 4828 // return current position of file pointer 4829 jlong os::current_file_offset(int fd) { 4830 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 4831 } 4832 4833 // move file pointer to the specified offset 4834 jlong os::seek_to_file_offset(int fd, jlong offset) { 4835 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 4836 } 4837 4838 // This code originates from JDK's sysAvailable 4839 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 4840 4841 int os::available(int fd, jlong *bytes) { 4842 jlong cur, end; 4843 int mode; 4844 struct stat64 buf64; 4845 4846 if (::fstat64(fd, &buf64) >= 0) { 4847 mode = buf64.st_mode; 4848 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 4849 /* 4850 * XXX: is the following call interruptible? If so, this might 4851 * need to go through the INTERRUPT_IO() wrapper as for other 4852 * blocking, interruptible calls in this file. 4853 */ 4854 int n; 4855 if (::ioctl(fd, FIONREAD, &n) >= 0) { 4856 *bytes = n; 4857 return 1; 4858 } 4859 } 4860 } 4861 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 4862 return 0; 4863 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 4864 return 0; 4865 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 4866 return 0; 4867 } 4868 *bytes = end - cur; 4869 return 1; 4870 } 4871 4872 int os::socket_available(int fd, jint *pbytes) { 4873 // Linux doc says EINTR not returned, unlike Solaris 4874 int ret = ::ioctl(fd, FIONREAD, pbytes); 4875 4876 //%% note ioctl can return 0 when successful, JVM_SocketAvailable 4877 // is expected to return 0 on failure and 1 on success to the jdk. 4878 return (ret < 0) ? 0 : 1; 4879 } 4880 4881 // Map a block of memory. 4882 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 4883 char *addr, size_t bytes, bool read_only, 4884 bool allow_exec) { 4885 int prot; 4886 int flags = MAP_PRIVATE; 4887 4888 if (read_only) { 4889 prot = PROT_READ; 4890 } else { 4891 prot = PROT_READ | PROT_WRITE; 4892 } 4893 4894 if (allow_exec) { 4895 prot |= PROT_EXEC; 4896 } 4897 4898 if (addr != NULL) { 4899 flags |= MAP_FIXED; 4900 } 4901 4902 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 4903 fd, file_offset); 4904 if (mapped_address == MAP_FAILED) { 4905 return NULL; 4906 } 4907 return mapped_address; 4908 } 4909 4910 4911 // Remap a block of memory. 4912 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 4913 char *addr, size_t bytes, bool read_only, 4914 bool allow_exec) { 4915 // same as map_memory() on this OS 4916 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 4917 allow_exec); 4918 } 4919 4920 4921 // Unmap a block of memory. 4922 bool os::pd_unmap_memory(char* addr, size_t bytes) { 4923 return munmap(addr, bytes) == 0; 4924 } 4925 4926 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 4927 4928 static clockid_t thread_cpu_clockid(Thread* thread) { 4929 pthread_t tid = thread->osthread()->pthread_id(); 4930 clockid_t clockid; 4931 4932 // Get thread clockid 4933 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 4934 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 4935 return clockid; 4936 } 4937 4938 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 4939 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 4940 // of a thread. 4941 // 4942 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 4943 // the fast estimate available on the platform. 4944 4945 jlong os::current_thread_cpu_time() { 4946 if (os::Linux::supports_fast_thread_cpu_time()) { 4947 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4948 } else { 4949 // return user + sys since the cost is the same 4950 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 4951 } 4952 } 4953 4954 jlong os::thread_cpu_time(Thread* thread) { 4955 // consistent with what current_thread_cpu_time() returns 4956 if (os::Linux::supports_fast_thread_cpu_time()) { 4957 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4958 } else { 4959 return slow_thread_cpu_time(thread, true /* user + sys */); 4960 } 4961 } 4962 4963 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 4964 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4965 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4966 } else { 4967 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 4968 } 4969 } 4970 4971 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4972 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4973 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4974 } else { 4975 return slow_thread_cpu_time(thread, user_sys_cpu_time); 4976 } 4977 } 4978 4979 // 4980 // -1 on error. 4981 // 4982 4983 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4984 static bool proc_task_unchecked = true; 4985 static const char *proc_stat_path = "/proc/%d/stat"; 4986 pid_t tid = thread->osthread()->thread_id(); 4987 char *s; 4988 char stat[2048]; 4989 int statlen; 4990 char proc_name[64]; 4991 int count; 4992 long sys_time, user_time; 4993 char cdummy; 4994 int idummy; 4995 long ldummy; 4996 FILE *fp; 4997 4998 // The /proc/<tid>/stat aggregates per-process usage on 4999 // new Linux kernels 2.6+ where NPTL is supported. 5000 // The /proc/self/task/<tid>/stat still has the per-thread usage. 5001 // See bug 6328462. 5002 // There possibly can be cases where there is no directory 5003 // /proc/self/task, so we check its availability. 5004 if (proc_task_unchecked && os::Linux::is_NPTL()) { 5005 // This is executed only once 5006 proc_task_unchecked = false; 5007 fp = fopen("/proc/self/task", "r"); 5008 if (fp != NULL) { 5009 proc_stat_path = "/proc/self/task/%d/stat"; 5010 fclose(fp); 5011 } 5012 } 5013 5014 sprintf(proc_name, proc_stat_path, tid); 5015 fp = fopen(proc_name, "r"); 5016 if ( fp == NULL ) return -1; 5017 statlen = fread(stat, 1, 2047, fp); 5018 stat[statlen] = '\0'; 5019 fclose(fp); 5020 5021 // Skip pid and the command string. Note that we could be dealing with 5022 // weird command names, e.g. user could decide to rename java launcher 5023 // to "java 1.4.2 :)", then the stat file would look like 5024 // 1234 (java 1.4.2 :)) R ... ... 5025 // We don't really need to know the command string, just find the last 5026 // occurrence of ")" and then start parsing from there. See bug 4726580. 5027 s = strrchr(stat, ')'); 5028 if (s == NULL ) return -1; 5029 5030 // Skip blank chars 5031 do s++; while (isspace(*s)); 5032 5033 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5034 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5035 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5036 &user_time, &sys_time); 5037 if ( count != 13 ) return -1; 5038 if (user_sys_cpu_time) { 5039 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5040 } else { 5041 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5042 } 5043 } 5044 5045 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5046 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5047 info_ptr->may_skip_backward = false; // elapsed time not wall time 5048 info_ptr->may_skip_forward = false; // elapsed time not wall time 5049 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5050 } 5051 5052 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5053 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5054 info_ptr->may_skip_backward = false; // elapsed time not wall time 5055 info_ptr->may_skip_forward = false; // elapsed time not wall time 5056 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5057 } 5058 5059 bool os::is_thread_cpu_time_supported() { 5060 return true; 5061 } 5062 5063 // System loadavg support. Returns -1 if load average cannot be obtained. 5064 // Linux doesn't yet have a (official) notion of processor sets, 5065 // so just return the system wide load average. 5066 int os::loadavg(double loadavg[], int nelem) { 5067 return ::getloadavg(loadavg, nelem); 5068 } 5069 5070 void os::pause() { 5071 char filename[MAX_PATH]; 5072 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5073 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 5074 } else { 5075 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5076 } 5077 5078 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5079 if (fd != -1) { 5080 struct stat buf; 5081 ::close(fd); 5082 while (::stat(filename, &buf) == 0) { 5083 (void)::poll(NULL, 0, 100); 5084 } 5085 } else { 5086 jio_fprintf(stderr, 5087 "Could not open pause file '%s', continuing immediately.\n", filename); 5088 } 5089 } 5090 5091 5092 // Refer to the comments in os_solaris.cpp park-unpark. 5093 // 5094 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 5095 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 5096 // For specifics regarding the bug see GLIBC BUGID 261237 : 5097 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 5098 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 5099 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 5100 // is used. (The simple C test-case provided in the GLIBC bug report manifests the 5101 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 5102 // and monitorenter when we're using 1-0 locking. All those operations may result in 5103 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 5104 // of libpthread avoids the problem, but isn't practical. 5105 // 5106 // Possible remedies: 5107 // 5108 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 5109 // This is palliative and probabilistic, however. If the thread is preempted 5110 // between the call to compute_abstime() and pthread_cond_timedwait(), more 5111 // than the minimum period may have passed, and the abstime may be stale (in the 5112 // past) resultin in a hang. Using this technique reduces the odds of a hang 5113 // but the JVM is still vulnerable, particularly on heavily loaded systems. 5114 // 5115 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 5116 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set 5117 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 5118 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant 5119 // thread. 5120 // 5121 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 5122 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 5123 // a timeout request to the chron thread and then blocking via pthread_cond_wait(). 5124 // This also works well. In fact it avoids kernel-level scalability impediments 5125 // on certain platforms that don't handle lots of active pthread_cond_timedwait() 5126 // timers in a graceful fashion. 5127 // 5128 // 4. When the abstime value is in the past it appears that control returns 5129 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 5130 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we 5131 // can avoid the problem by reinitializing the condvar -- by cond_destroy() 5132 // followed by cond_init() -- after all calls to pthread_cond_timedwait(). 5133 // It may be possible to avoid reinitialization by checking the return 5134 // value from pthread_cond_timedwait(). In addition to reinitializing the 5135 // condvar we must establish the invariant that cond_signal() is only called 5136 // within critical sections protected by the adjunct mutex. This prevents 5137 // cond_signal() from "seeing" a condvar that's in the midst of being 5138 // reinitialized or that is corrupt. Sadly, this invariant obviates the 5139 // desirable signal-after-unlock optimization that avoids futile context switching. 5140 // 5141 // I'm also concerned that some versions of NTPL might allocate an auxilliary 5142 // structure when a condvar is used or initialized. cond_destroy() would 5143 // release the helper structure. Our reinitialize-after-timedwait fix 5144 // put excessive stress on malloc/free and locks protecting the c-heap. 5145 // 5146 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 5147 // It may be possible to refine (4) by checking the kernel and NTPL verisons 5148 // and only enabling the work-around for vulnerable environments. 5149 5150 // utility to compute the abstime argument to timedwait: 5151 // millis is the relative timeout time 5152 // abstime will be the absolute timeout time 5153 // TODO: replace compute_abstime() with unpackTime() 5154 5155 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5156 if (millis < 0) millis = 0; 5157 struct timeval now; 5158 int status = gettimeofday(&now, NULL); 5159 assert(status == 0, "gettimeofday"); 5160 jlong seconds = millis / 1000; 5161 millis %= 1000; 5162 if (seconds > 50000000) { // see man cond_timedwait(3T) 5163 seconds = 50000000; 5164 } 5165 abstime->tv_sec = now.tv_sec + seconds; 5166 long usec = now.tv_usec + millis * 1000; 5167 if (usec >= 1000000) { 5168 abstime->tv_sec += 1; 5169 usec -= 1000000; 5170 } 5171 abstime->tv_nsec = usec * 1000; 5172 return abstime; 5173 } 5174 5175 5176 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately. 5177 // Conceptually TryPark() should be equivalent to park(0). 5178 5179 int os::PlatformEvent::TryPark() { 5180 for (;;) { 5181 const int v = _Event ; 5182 guarantee ((v == 0) || (v == 1), "invariant") ; 5183 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ; 5184 } 5185 } 5186 5187 void os::PlatformEvent::park() { // AKA "down()" 5188 // Invariant: Only the thread associated with the Event/PlatformEvent 5189 // may call park(). 5190 // TODO: assert that _Assoc != NULL or _Assoc == Self 5191 int v ; 5192 for (;;) { 5193 v = _Event ; 5194 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 5195 } 5196 guarantee (v >= 0, "invariant") ; 5197 if (v == 0) { 5198 // Do this the hard way by blocking ... 5199 int status = pthread_mutex_lock(_mutex); 5200 assert_status(status == 0, status, "mutex_lock"); 5201 guarantee (_nParked == 0, "invariant") ; 5202 ++ _nParked ; 5203 while (_Event < 0) { 5204 status = pthread_cond_wait(_cond, _mutex); 5205 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5206 // Treat this the same as if the wait was interrupted 5207 if (status == ETIME) { status = EINTR; } 5208 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5209 } 5210 -- _nParked ; 5211 5212 _Event = 0 ; 5213 status = pthread_mutex_unlock(_mutex); 5214 assert_status(status == 0, status, "mutex_unlock"); 5215 // Paranoia to ensure our locked and lock-free paths interact 5216 // correctly with each other. 5217 OrderAccess::fence(); 5218 } 5219 guarantee (_Event >= 0, "invariant") ; 5220 } 5221 5222 int os::PlatformEvent::park(jlong millis) { 5223 guarantee (_nParked == 0, "invariant") ; 5224 5225 int v ; 5226 for (;;) { 5227 v = _Event ; 5228 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 5229 } 5230 guarantee (v >= 0, "invariant") ; 5231 if (v != 0) return OS_OK ; 5232 5233 // We do this the hard way, by blocking the thread. 5234 // Consider enforcing a minimum timeout value. 5235 struct timespec abst; 5236 compute_abstime(&abst, millis); 5237 5238 int ret = OS_TIMEOUT; 5239 int status = pthread_mutex_lock(_mutex); 5240 assert_status(status == 0, status, "mutex_lock"); 5241 guarantee (_nParked == 0, "invariant") ; 5242 ++_nParked ; 5243 5244 // Object.wait(timo) will return because of 5245 // (a) notification 5246 // (b) timeout 5247 // (c) thread.interrupt 5248 // 5249 // Thread.interrupt and object.notify{All} both call Event::set. 5250 // That is, we treat thread.interrupt as a special case of notification. 5251 // The underlying Solaris implementation, cond_timedwait, admits 5252 // spurious/premature wakeups, but the JLS/JVM spec prevents the 5253 // JVM from making those visible to Java code. As such, we must 5254 // filter out spurious wakeups. We assume all ETIME returns are valid. 5255 // 5256 // TODO: properly differentiate simultaneous notify+interrupt. 5257 // In that case, we should propagate the notify to another waiter. 5258 5259 while (_Event < 0) { 5260 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst); 5261 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5262 pthread_cond_destroy (_cond); 5263 pthread_cond_init (_cond, NULL) ; 5264 } 5265 assert_status(status == 0 || status == EINTR || 5266 status == ETIME || status == ETIMEDOUT, 5267 status, "cond_timedwait"); 5268 if (!FilterSpuriousWakeups) break ; // previous semantics 5269 if (status == ETIME || status == ETIMEDOUT) break ; 5270 // We consume and ignore EINTR and spurious wakeups. 5271 } 5272 --_nParked ; 5273 if (_Event >= 0) { 5274 ret = OS_OK; 5275 } 5276 _Event = 0 ; 5277 status = pthread_mutex_unlock(_mutex); 5278 assert_status(status == 0, status, "mutex_unlock"); 5279 assert (_nParked == 0, "invariant") ; 5280 // Paranoia to ensure our locked and lock-free paths interact 5281 // correctly with each other. 5282 OrderAccess::fence(); 5283 return ret; 5284 } 5285 5286 void os::PlatformEvent::unpark() { 5287 // Transitions for _Event: 5288 // 0 :=> 1 5289 // 1 :=> 1 5290 // -1 :=> either 0 or 1; must signal target thread 5291 // That is, we can safely transition _Event from -1 to either 5292 // 0 or 1. Forcing 1 is slightly more efficient for back-to-back 5293 // unpark() calls. 5294 // See also: "Semaphores in Plan 9" by Mullender & Cox 5295 // 5296 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5297 // that it will take two back-to-back park() calls for the owning 5298 // thread to block. This has the benefit of forcing a spurious return 5299 // from the first park() call after an unpark() call which will help 5300 // shake out uses of park() and unpark() without condition variables. 5301 5302 if (Atomic::xchg(1, &_Event) >= 0) return; 5303 5304 // Wait for the thread associated with the event to vacate 5305 int status = pthread_mutex_lock(_mutex); 5306 assert_status(status == 0, status, "mutex_lock"); 5307 int AnyWaiters = _nParked; 5308 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5309 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 5310 AnyWaiters = 0; 5311 pthread_cond_signal(_cond); 5312 } 5313 status = pthread_mutex_unlock(_mutex); 5314 assert_status(status == 0, status, "mutex_unlock"); 5315 if (AnyWaiters != 0) { 5316 status = pthread_cond_signal(_cond); 5317 assert_status(status == 0, status, "cond_signal"); 5318 } 5319 5320 // Note that we signal() _after dropping the lock for "immortal" Events. 5321 // This is safe and avoids a common class of futile wakeups. In rare 5322 // circumstances this can cause a thread to return prematurely from 5323 // cond_{timed}wait() but the spurious wakeup is benign and the victim will 5324 // simply re-test the condition and re-park itself. 5325 } 5326 5327 5328 // JSR166 5329 // ------------------------------------------------------- 5330 5331 /* 5332 * The solaris and linux implementations of park/unpark are fairly 5333 * conservative for now, but can be improved. They currently use a 5334 * mutex/condvar pair, plus a a count. 5335 * Park decrements count if > 0, else does a condvar wait. Unpark 5336 * sets count to 1 and signals condvar. Only one thread ever waits 5337 * on the condvar. Contention seen when trying to park implies that someone 5338 * is unparking you, so don't wait. And spurious returns are fine, so there 5339 * is no need to track notifications. 5340 */ 5341 5342 #define MAX_SECS 100000000 5343 /* 5344 * This code is common to linux and solaris and will be moved to a 5345 * common place in dolphin. 5346 * 5347 * The passed in time value is either a relative time in nanoseconds 5348 * or an absolute time in milliseconds. Either way it has to be unpacked 5349 * into suitable seconds and nanoseconds components and stored in the 5350 * given timespec structure. 5351 * Given time is a 64-bit value and the time_t used in the timespec is only 5352 * a signed-32-bit value (except on 64-bit Linux) we have to watch for 5353 * overflow if times way in the future are given. Further on Solaris versions 5354 * prior to 10 there is a restriction (see cond_timedwait) that the specified 5355 * number of seconds, in abstime, is less than current_time + 100,000,000. 5356 * As it will be 28 years before "now + 100000000" will overflow we can 5357 * ignore overflow and just impose a hard-limit on seconds using the value 5358 * of "now + 100,000,000". This places a limit on the timeout of about 3.17 5359 * years from "now". 5360 */ 5361 5362 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5363 assert (time > 0, "convertTime"); 5364 5365 struct timeval now; 5366 int status = gettimeofday(&now, NULL); 5367 assert(status == 0, "gettimeofday"); 5368 5369 time_t max_secs = now.tv_sec + MAX_SECS; 5370 5371 if (isAbsolute) { 5372 jlong secs = time / 1000; 5373 if (secs > max_secs) { 5374 absTime->tv_sec = max_secs; 5375 } 5376 else { 5377 absTime->tv_sec = secs; 5378 } 5379 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5380 } 5381 else { 5382 jlong secs = time / NANOSECS_PER_SEC; 5383 if (secs >= MAX_SECS) { 5384 absTime->tv_sec = max_secs; 5385 absTime->tv_nsec = 0; 5386 } 5387 else { 5388 absTime->tv_sec = now.tv_sec + secs; 5389 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5390 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5391 absTime->tv_nsec -= NANOSECS_PER_SEC; 5392 ++absTime->tv_sec; // note: this must be <= max_secs 5393 } 5394 } 5395 } 5396 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5397 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5398 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5399 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5400 } 5401 5402 void Parker::park(bool isAbsolute, jlong time) { 5403 // Ideally we'd do something useful while spinning, such 5404 // as calling unpackTime(). 5405 5406 // Optional fast-path check: 5407 // Return immediately if a permit is available. 5408 // We depend on Atomic::xchg() having full barrier semantics 5409 // since we are doing a lock-free update to _counter. 5410 if (Atomic::xchg(0, &_counter) > 0) return; 5411 5412 Thread* thread = Thread::current(); 5413 assert(thread->is_Java_thread(), "Must be JavaThread"); 5414 JavaThread *jt = (JavaThread *)thread; 5415 5416 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5417 // Check interrupt before trying to wait 5418 if (Thread::is_interrupted(thread, false)) { 5419 return; 5420 } 5421 5422 // Next, demultiplex/decode time arguments 5423 timespec absTime; 5424 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all 5425 return; 5426 } 5427 if (time > 0) { 5428 unpackTime(&absTime, isAbsolute, time); 5429 } 5430 5431 5432 // Enter safepoint region 5433 // Beware of deadlocks such as 6317397. 5434 // The per-thread Parker:: mutex is a classic leaf-lock. 5435 // In particular a thread must never block on the Threads_lock while 5436 // holding the Parker:: mutex. If safepoints are pending both the 5437 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5438 ThreadBlockInVM tbivm(jt); 5439 5440 // Don't wait if cannot get lock since interference arises from 5441 // unblocking. Also. check interrupt before trying wait 5442 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5443 return; 5444 } 5445 5446 int status ; 5447 if (_counter > 0) { // no wait needed 5448 _counter = 0; 5449 status = pthread_mutex_unlock(_mutex); 5450 assert (status == 0, "invariant") ; 5451 // Paranoia to ensure our locked and lock-free paths interact 5452 // correctly with each other and Java-level accesses. 5453 OrderAccess::fence(); 5454 return; 5455 } 5456 5457 #ifdef ASSERT 5458 // Don't catch signals while blocked; let the running threads have the signals. 5459 // (This allows a debugger to break into the running thread.) 5460 sigset_t oldsigs; 5461 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5462 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5463 #endif 5464 5465 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5466 jt->set_suspend_equivalent(); 5467 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5468 5469 if (time == 0) { 5470 status = pthread_cond_wait (_cond, _mutex) ; 5471 } else { 5472 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ; 5473 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5474 pthread_cond_destroy (_cond) ; 5475 pthread_cond_init (_cond, NULL); 5476 } 5477 } 5478 assert_status(status == 0 || status == EINTR || 5479 status == ETIME || status == ETIMEDOUT, 5480 status, "cond_timedwait"); 5481 5482 #ifdef ASSERT 5483 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5484 #endif 5485 5486 _counter = 0 ; 5487 status = pthread_mutex_unlock(_mutex) ; 5488 assert_status(status == 0, status, "invariant") ; 5489 // Paranoia to ensure our locked and lock-free paths interact 5490 // correctly with each other and Java-level accesses. 5491 OrderAccess::fence(); 5492 5493 // If externally suspended while waiting, re-suspend 5494 if (jt->handle_special_suspend_equivalent_condition()) { 5495 jt->java_suspend_self(); 5496 } 5497 } 5498 5499 void Parker::unpark() { 5500 int s, status ; 5501 status = pthread_mutex_lock(_mutex); 5502 assert (status == 0, "invariant") ; 5503 s = _counter; 5504 _counter = 1; 5505 if (s < 1) { 5506 if (WorkAroundNPTLTimedWaitHang) { 5507 status = pthread_cond_signal (_cond) ; 5508 assert (status == 0, "invariant") ; 5509 status = pthread_mutex_unlock(_mutex); 5510 assert (status == 0, "invariant") ; 5511 } else { 5512 status = pthread_mutex_unlock(_mutex); 5513 assert (status == 0, "invariant") ; 5514 status = pthread_cond_signal (_cond) ; 5515 assert (status == 0, "invariant") ; 5516 } 5517 } else { 5518 pthread_mutex_unlock(_mutex); 5519 assert (status == 0, "invariant") ; 5520 } 5521 } 5522 5523 5524 extern char** environ; 5525 5526 #ifndef __NR_fork 5527 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) 5528 #endif 5529 5530 #ifndef __NR_execve 5531 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) 5532 #endif 5533 5534 // Run the specified command in a separate process. Return its exit value, 5535 // or -1 on failure (e.g. can't fork a new process). 5536 // Unlike system(), this function can be called from signal handler. It 5537 // doesn't block SIGINT et al. 5538 int os::fork_and_exec(char* cmd) { 5539 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5540 5541 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run 5542 // pthread_atfork handlers and reset pthread library. All we need is a 5543 // separate process to execve. Make a direct syscall to fork process. 5544 // On IA64 there's no fork syscall, we have to use fork() and hope for 5545 // the best... 5546 pid_t pid = NOT_IA64(syscall(__NR_fork);) 5547 IA64_ONLY(fork();) 5548 5549 if (pid < 0) { 5550 // fork failed 5551 return -1; 5552 5553 } else if (pid == 0) { 5554 // child process 5555 5556 // execve() in LinuxThreads will call pthread_kill_other_threads_np() 5557 // first to kill every thread on the thread list. Because this list is 5558 // not reset by fork() (see notes above), execve() will instead kill 5559 // every thread in the parent process. We know this is the only thread 5560 // in the new process, so make a system call directly. 5561 // IA64 should use normal execve() from glibc to match the glibc fork() 5562 // above. 5563 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);) 5564 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);) 5565 5566 // execve failed 5567 _exit(-1); 5568 5569 } else { 5570 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5571 // care about the actual exit code, for now. 5572 5573 int status; 5574 5575 // Wait for the child process to exit. This returns immediately if 5576 // the child has already exited. */ 5577 while (waitpid(pid, &status, 0) < 0) { 5578 switch (errno) { 5579 case ECHILD: return 0; 5580 case EINTR: break; 5581 default: return -1; 5582 } 5583 } 5584 5585 if (WIFEXITED(status)) { 5586 // The child exited normally; get its exit code. 5587 return WEXITSTATUS(status); 5588 } else if (WIFSIGNALED(status)) { 5589 // The child exited because of a signal 5590 // The best value to return is 0x80 + signal number, 5591 // because that is what all Unix shells do, and because 5592 // it allows callers to distinguish between process exit and 5593 // process death by signal. 5594 return 0x80 + WTERMSIG(status); 5595 } else { 5596 // Unknown exit code; pass it through 5597 return status; 5598 } 5599 } 5600 } 5601 5602 // is_headless_jre() 5603 // 5604 // Test for the existence of xawt/libmawt.so or libawt_xawt.so 5605 // in order to report if we are running in a headless jre 5606 // 5607 // Since JDK8 xawt/libmawt.so was moved into the same directory 5608 // as libawt.so, and renamed libawt_xawt.so 5609 // 5610 bool os::is_headless_jre() { 5611 struct stat statbuf; 5612 char buf[MAXPATHLEN]; 5613 char libmawtpath[MAXPATHLEN]; 5614 const char *xawtstr = "/xawt/libmawt.so"; 5615 const char *new_xawtstr = "/libawt_xawt.so"; 5616 char *p; 5617 5618 // Get path to libjvm.so 5619 os::jvm_path(buf, sizeof(buf)); 5620 5621 // Get rid of libjvm.so 5622 p = strrchr(buf, '/'); 5623 if (p == NULL) return false; 5624 else *p = '\0'; 5625 5626 // Get rid of client or server 5627 p = strrchr(buf, '/'); 5628 if (p == NULL) return false; 5629 else *p = '\0'; 5630 5631 // check xawt/libmawt.so 5632 strcpy(libmawtpath, buf); 5633 strcat(libmawtpath, xawtstr); 5634 if (::stat(libmawtpath, &statbuf) == 0) return false; 5635 5636 // check libawt_xawt.so 5637 strcpy(libmawtpath, buf); 5638 strcat(libmawtpath, new_xawtstr); 5639 if (::stat(libmawtpath, &statbuf) == 0) return false; 5640 5641 return true; 5642 } 5643 5644 // Get the default path to the core file 5645 // Returns the length of the string 5646 int os::get_core_path(char* buffer, size_t bufferSize) { 5647 const char* p = get_current_directory(buffer, bufferSize); 5648 5649 if (p == NULL) { 5650 assert(p != NULL, "failed to get current directory"); 5651 return 0; 5652 } 5653 5654 return strlen(buffer); 5655 } 5656 5657 #ifdef JAVASE_EMBEDDED 5658 // 5659 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory. 5660 // 5661 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL; 5662 5663 // ctor 5664 // 5665 MemNotifyThread::MemNotifyThread(int fd): Thread() { 5666 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread"); 5667 _fd = fd; 5668 5669 if (os::create_thread(this, os::os_thread)) { 5670 _memnotify_thread = this; 5671 os::set_priority(this, NearMaxPriority); 5672 os::start_thread(this); 5673 } 5674 } 5675 5676 // Where all the work gets done 5677 // 5678 void MemNotifyThread::run() { 5679 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread"); 5680 5681 // Set up the select arguments 5682 fd_set rfds; 5683 if (_fd != -1) { 5684 FD_ZERO(&rfds); 5685 FD_SET(_fd, &rfds); 5686 } 5687 5688 // Now wait for the mem_notify device to wake up 5689 while (1) { 5690 // Wait for the mem_notify device to signal us.. 5691 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL); 5692 if (rc == -1) { 5693 perror("select!\n"); 5694 break; 5695 } else if (rc) { 5696 //ssize_t free_before = os::available_memory(); 5697 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024); 5698 5699 // The kernel is telling us there is not much memory left... 5700 // try to do something about that 5701 5702 // If we are not already in a GC, try one. 5703 if (!Universe::heap()->is_gc_active()) { 5704 Universe::heap()->collect(GCCause::_allocation_failure); 5705 5706 //ssize_t free_after = os::available_memory(); 5707 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024); 5708 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024); 5709 } 5710 // We might want to do something like the following if we find the GC's are not helping... 5711 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true); 5712 } 5713 } 5714 } 5715 5716 // 5717 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it. 5718 // 5719 void MemNotifyThread::start() { 5720 int fd; 5721 fd = open ("/dev/mem_notify", O_RDONLY, 0); 5722 if (fd < 0) { 5723 return; 5724 } 5725 5726 if (memnotify_thread() == NULL) { 5727 new MemNotifyThread(fd); 5728 } 5729 } 5730 5731 #endif // JAVASE_EMBEDDED