1 /* 2 * Copyright (c) 1999, 2012, 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 "interpreter/interpreter.hpp" 33 #include "jvm_linux.h" 34 #include "memory/allocation.inline.hpp" 35 #include "memory/filemap.hpp" 36 #include "mutex_linux.inline.hpp" 37 #include "oops/oop.inline.hpp" 38 #include "os_share_linux.hpp" 39 #include "prims/jniFastGetField.hpp" 40 #include "prims/jvm.h" 41 #include "prims/jvm_misc.hpp" 42 #include "runtime/arguments.hpp" 43 #include "runtime/extendedPC.hpp" 44 #include "runtime/globals.hpp" 45 #include "runtime/interfaceSupport.hpp" 46 #include "runtime/java.hpp" 47 #include "runtime/javaCalls.hpp" 48 #include "runtime/mutexLocker.hpp" 49 #include "runtime/objectMonitor.hpp" 50 #include "runtime/osThread.hpp" 51 #include "runtime/perfMemory.hpp" 52 #include "runtime/sharedRuntime.hpp" 53 #include "runtime/statSampler.hpp" 54 #include "runtime/stubRoutines.hpp" 55 #include "runtime/threadCritical.hpp" 56 #include "runtime/timer.hpp" 57 #include "services/attachListener.hpp" 58 #include "services/runtimeService.hpp" 59 #include "thread_linux.inline.hpp" 60 #include "utilities/decoder.hpp" 61 #include "utilities/defaultStream.hpp" 62 #include "utilities/events.hpp" 63 #include "utilities/growableArray.hpp" 64 #include "utilities/vmError.hpp" 65 #ifdef TARGET_ARCH_x86 66 # include "assembler_x86.inline.hpp" 67 # include "nativeInst_x86.hpp" 68 #endif 69 #ifdef TARGET_ARCH_sparc 70 # include "assembler_sparc.inline.hpp" 71 # include "nativeInst_sparc.hpp" 72 #endif 73 #ifdef TARGET_ARCH_zero 74 # include "assembler_zero.inline.hpp" 75 # include "nativeInst_zero.hpp" 76 #endif 77 #ifdef TARGET_ARCH_arm 78 # include "assembler_arm.inline.hpp" 79 # include "nativeInst_arm.hpp" 80 #endif 81 #ifdef TARGET_ARCH_ppc 82 # include "assembler_ppc.inline.hpp" 83 # include "nativeInst_ppc.hpp" 84 #endif 85 #ifdef COMPILER1 86 #include "c1/c1_Runtime1.hpp" 87 #endif 88 #ifdef COMPILER2 89 #include "opto/runtime.hpp" 90 #endif 91 92 // put OS-includes here 93 # include <sys/types.h> 94 # include <sys/mman.h> 95 # include <sys/stat.h> 96 # include <sys/select.h> 97 # include <pthread.h> 98 # include <signal.h> 99 # include <errno.h> 100 # include <dlfcn.h> 101 # include <stdio.h> 102 # include <unistd.h> 103 # include <sys/resource.h> 104 # include <pthread.h> 105 # include <sys/stat.h> 106 # include <sys/time.h> 107 # include <sys/times.h> 108 # include <sys/utsname.h> 109 # include <sys/socket.h> 110 # include <sys/wait.h> 111 # include <pwd.h> 112 # include <poll.h> 113 # include <semaphore.h> 114 # include <fcntl.h> 115 # include <string.h> 116 # include <syscall.h> 117 # include <sys/sysinfo.h> 118 # include <gnu/libc-version.h> 119 # include <sys/ipc.h> 120 # include <sys/shm.h> 121 # include <link.h> 122 # include <stdint.h> 123 # include <inttypes.h> 124 # include <sys/ioctl.h> 125 126 #define MAX_PATH (2 * K) 127 128 // for timer info max values which include all bits 129 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 130 131 #define LARGEPAGES_BIT (1 << 6) 132 //////////////////////////////////////////////////////////////////////////////// 133 // global variables 134 julong os::Linux::_physical_memory = 0; 135 136 address os::Linux::_initial_thread_stack_bottom = NULL; 137 uintptr_t os::Linux::_initial_thread_stack_size = 0; 138 139 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 140 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 141 Mutex* os::Linux::_createThread_lock = NULL; 142 pthread_t os::Linux::_main_thread; 143 int os::Linux::_page_size = -1; 144 bool os::Linux::_is_floating_stack = false; 145 bool os::Linux::_is_NPTL = false; 146 bool os::Linux::_supports_fast_thread_cpu_time = false; 147 const char * os::Linux::_glibc_version = NULL; 148 const char * os::Linux::_libpthread_version = NULL; 149 150 static jlong initial_time_count=0; 151 152 static int clock_tics_per_sec = 100; 153 154 // For diagnostics to print a message once. see run_periodic_checks 155 static sigset_t check_signal_done; 156 static bool check_signals = true;; 157 158 static pid_t _initial_pid = 0; 159 160 /* Signal number used to suspend/resume a thread */ 161 162 /* do not use any signal number less than SIGSEGV, see 4355769 */ 163 static int SR_signum = SIGUSR2; 164 sigset_t SR_sigset; 165 166 /* Used to protect dlsym() calls */ 167 static pthread_mutex_t dl_mutex; 168 169 #ifdef JAVASE_EMBEDDED 170 class MemNotifyThread: public Thread { 171 friend class VMStructs; 172 public: 173 virtual void run(); 174 175 private: 176 static MemNotifyThread* _memnotify_thread; 177 int _fd; 178 179 public: 180 181 // Constructor 182 MemNotifyThread(int fd); 183 184 // Tester 185 bool is_memnotify_thread() const { return true; } 186 187 // Printing 188 char* name() const { return (char*)"Linux MemNotify Thread"; } 189 190 // Returns the single instance of the MemNotifyThread 191 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; } 192 193 // Create and start the single instance of MemNotifyThread 194 static void start(); 195 }; 196 #endif // JAVASE_EMBEDDED 197 198 // utility functions 199 200 static int SR_initialize(); 201 static int SR_finalize(); 202 203 julong os::available_memory() { 204 return Linux::available_memory(); 205 } 206 207 julong os::Linux::available_memory() { 208 // values in struct sysinfo are "unsigned long" 209 struct sysinfo si; 210 sysinfo(&si); 211 212 return (julong)si.freeram * si.mem_unit; 213 } 214 215 julong os::physical_memory() { 216 return Linux::physical_memory(); 217 } 218 219 julong os::allocatable_physical_memory(julong size) { 220 #ifdef _LP64 221 return size; 222 #else 223 julong result = MIN2(size, (julong)3800*M); 224 if (!is_allocatable(result)) { 225 // See comments under solaris for alignment considerations 226 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size(); 227 result = MIN2(size, reasonable_size); 228 } 229 return result; 230 #endif // _LP64 231 } 232 233 //////////////////////////////////////////////////////////////////////////////// 234 // environment support 235 236 bool os::getenv(const char* name, char* buf, int len) { 237 const char* val = ::getenv(name); 238 if (val != NULL && strlen(val) < (size_t)len) { 239 strcpy(buf, val); 240 return true; 241 } 242 if (len > 0) buf[0] = 0; // return a null string 243 return false; 244 } 245 246 247 // Return true if user is running as root. 248 249 bool os::have_special_privileges() { 250 static bool init = false; 251 static bool privileges = false; 252 if (!init) { 253 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 254 init = true; 255 } 256 return privileges; 257 } 258 259 260 #ifndef SYS_gettid 261 // i386: 224, ia64: 1105, amd64: 186, sparc 143 262 #ifdef __ia64__ 263 #define SYS_gettid 1105 264 #elif __i386__ 265 #define SYS_gettid 224 266 #elif __amd64__ 267 #define SYS_gettid 186 268 #elif __sparc__ 269 #define SYS_gettid 143 270 #else 271 #error define gettid for the arch 272 #endif 273 #endif 274 275 // Cpu architecture string 276 #if defined(ZERO) 277 static char cpu_arch[] = ZERO_LIBARCH; 278 #elif defined(IA64) 279 static char cpu_arch[] = "ia64"; 280 #elif defined(IA32) 281 static char cpu_arch[] = "i386"; 282 #elif defined(AMD64) 283 static char cpu_arch[] = "amd64"; 284 #elif defined(ARM) 285 static char cpu_arch[] = "arm"; 286 #elif defined(PPC) 287 static char cpu_arch[] = "ppc"; 288 #elif defined(SPARC) 289 # ifdef _LP64 290 static char cpu_arch[] = "sparcv9"; 291 # else 292 static char cpu_arch[] = "sparc"; 293 # endif 294 #else 295 #error Add appropriate cpu_arch setting 296 #endif 297 298 299 // pid_t gettid() 300 // 301 // Returns the kernel thread id of the currently running thread. Kernel 302 // thread id is used to access /proc. 303 // 304 // (Note that getpid() on LinuxThreads returns kernel thread id too; but 305 // on NPTL, it returns the same pid for all threads, as required by POSIX.) 306 // 307 pid_t os::Linux::gettid() { 308 int rslt = syscall(SYS_gettid); 309 if (rslt == -1) { 310 // old kernel, no NPTL support 311 return getpid(); 312 } else { 313 return (pid_t)rslt; 314 } 315 } 316 317 // Most versions of linux have a bug where the number of processors are 318 // determined by looking at the /proc file system. In a chroot environment, 319 // the system call returns 1. This causes the VM to act as if it is 320 // a single processor and elide locking (see is_MP() call). 321 static bool unsafe_chroot_detected = false; 322 static const char *unstable_chroot_error = "/proc file system not found.\n" 323 "Java may be unstable running multithreaded in a chroot " 324 "environment on Linux when /proc filesystem is not mounted."; 325 326 void os::Linux::initialize_system_info() { 327 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 328 if (processor_count() == 1) { 329 pid_t pid = os::Linux::gettid(); 330 char fname[32]; 331 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 332 FILE *fp = fopen(fname, "r"); 333 if (fp == NULL) { 334 unsafe_chroot_detected = true; 335 } else { 336 fclose(fp); 337 } 338 } 339 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 340 assert(processor_count() > 0, "linux error"); 341 } 342 343 void os::init_system_properties_values() { 344 // char arch[12]; 345 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch)); 346 347 // The next steps are taken in the product version: 348 // 349 // Obtain the JAVA_HOME value from the location of libjvm[_g].so. 350 // This library should be located at: 351 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so. 352 // 353 // If "/jre/lib/" appears at the right place in the path, then we 354 // assume libjvm[_g].so is installed in a JDK and we use this path. 355 // 356 // Otherwise exit with message: "Could not create the Java virtual machine." 357 // 358 // The following extra steps are taken in the debugging version: 359 // 360 // If "/jre/lib/" does NOT appear at the right place in the path 361 // instead of exit check for $JAVA_HOME environment variable. 362 // 363 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 364 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so 365 // it looks like libjvm[_g].so is installed there 366 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so. 367 // 368 // Otherwise exit. 369 // 370 // Important note: if the location of libjvm.so changes this 371 // code needs to be changed accordingly. 372 373 // The next few definitions allow the code to be verbatim: 374 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n)) 375 #define getenv(n) ::getenv(n) 376 377 /* 378 * See ld(1): 379 * The linker uses the following search paths to locate required 380 * shared libraries: 381 * 1: ... 382 * ... 383 * 7: The default directories, normally /lib and /usr/lib. 384 */ 385 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 386 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 387 #else 388 #define DEFAULT_LIBPATH "/lib:/usr/lib" 389 #endif 390 391 #define EXTENSIONS_DIR "/lib/ext" 392 #define ENDORSED_DIR "/lib/endorsed" 393 #define REG_DIR "/usr/java/packages" 394 395 { 396 /* sysclasspath, java_home, dll_dir */ 397 { 398 char *home_path; 399 char *dll_path; 400 char *pslash; 401 char buf[MAXPATHLEN]; 402 os::jvm_path(buf, sizeof(buf)); 403 404 // Found the full path to libjvm.so. 405 // Now cut the path to <java_home>/jre if we can. 406 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */ 407 pslash = strrchr(buf, '/'); 408 if (pslash != NULL) 409 *pslash = '\0'; /* get rid of /{client|server|hotspot} */ 410 dll_path = malloc(strlen(buf) + 1); 411 if (dll_path == NULL) 412 return; 413 strcpy(dll_path, buf); 414 Arguments::set_dll_dir(dll_path); 415 416 if (pslash != NULL) { 417 pslash = strrchr(buf, '/'); 418 if (pslash != NULL) { 419 *pslash = '\0'; /* get rid of /<arch> */ 420 pslash = strrchr(buf, '/'); 421 if (pslash != NULL) 422 *pslash = '\0'; /* get rid of /lib */ 423 } 424 } 425 426 home_path = malloc(strlen(buf) + 1); 427 if (home_path == NULL) 428 return; 429 strcpy(home_path, buf); 430 Arguments::set_java_home(home_path); 431 432 if (!set_boot_path('/', ':')) 433 return; 434 } 435 436 /* 437 * Where to look for native libraries 438 * 439 * Note: Due to a legacy implementation, most of the library path 440 * is set in the launcher. This was to accomodate linking restrictions 441 * on legacy Linux implementations (which are no longer supported). 442 * Eventually, all the library path setting will be done here. 443 * 444 * However, to prevent the proliferation of improperly built native 445 * libraries, the new path component /usr/java/packages is added here. 446 * Eventually, all the library path setting will be done here. 447 */ 448 { 449 char *ld_library_path; 450 451 /* 452 * Construct the invariant part of ld_library_path. Note that the 453 * space for the colon and the trailing null are provided by the 454 * nulls included by the sizeof operator (so actually we allocate 455 * a byte more than necessary). 456 */ 457 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") + 458 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH)); 459 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch); 460 461 /* 462 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It 463 * should always exist (until the legacy problem cited above is 464 * addressed). 465 */ 466 char *v = getenv("LD_LIBRARY_PATH"); 467 if (v != NULL) { 468 char *t = ld_library_path; 469 /* That's +1 for the colon and +1 for the trailing '\0' */ 470 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1); 471 sprintf(ld_library_path, "%s:%s", v, t); 472 } 473 Arguments::set_library_path(ld_library_path); 474 } 475 476 /* 477 * Extensions directories. 478 * 479 * Note that the space for the colon and the trailing null are provided 480 * by the nulls included by the sizeof operator (so actually one byte more 481 * than necessary is allocated). 482 */ 483 { 484 char *buf = malloc(strlen(Arguments::get_java_home()) + 485 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR)); 486 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR, 487 Arguments::get_java_home()); 488 Arguments::set_ext_dirs(buf); 489 } 490 491 /* Endorsed standards default directory. */ 492 { 493 char * buf; 494 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR)); 495 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home()); 496 Arguments::set_endorsed_dirs(buf); 497 } 498 } 499 500 #undef malloc 501 #undef getenv 502 #undef EXTENSIONS_DIR 503 #undef ENDORSED_DIR 504 505 // Done 506 return; 507 } 508 509 //////////////////////////////////////////////////////////////////////////////// 510 // breakpoint support 511 512 void os::breakpoint() { 513 BREAKPOINT; 514 } 515 516 extern "C" void breakpoint() { 517 // use debugger to set breakpoint here 518 } 519 520 //////////////////////////////////////////////////////////////////////////////// 521 // signal support 522 523 debug_only(static bool signal_sets_initialized = false); 524 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 525 526 bool os::Linux::is_sig_ignored(int sig) { 527 struct sigaction oact; 528 sigaction(sig, (struct sigaction*)NULL, &oact); 529 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 530 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 531 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) 532 return true; 533 else 534 return false; 535 } 536 537 void os::Linux::signal_sets_init() { 538 // Should also have an assertion stating we are still single-threaded. 539 assert(!signal_sets_initialized, "Already initialized"); 540 // Fill in signals that are necessarily unblocked for all threads in 541 // the VM. Currently, we unblock the following signals: 542 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 543 // by -Xrs (=ReduceSignalUsage)); 544 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 545 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 546 // the dispositions or masks wrt these signals. 547 // Programs embedding the VM that want to use the above signals for their 548 // own purposes must, at this time, use the "-Xrs" option to prevent 549 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 550 // (See bug 4345157, and other related bugs). 551 // In reality, though, unblocking these signals is really a nop, since 552 // these signals are not blocked by default. 553 sigemptyset(&unblocked_sigs); 554 sigemptyset(&allowdebug_blocked_sigs); 555 sigaddset(&unblocked_sigs, SIGILL); 556 sigaddset(&unblocked_sigs, SIGSEGV); 557 sigaddset(&unblocked_sigs, SIGBUS); 558 sigaddset(&unblocked_sigs, SIGFPE); 559 sigaddset(&unblocked_sigs, SR_signum); 560 561 if (!ReduceSignalUsage) { 562 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 563 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 564 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 565 } 566 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 567 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 568 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 569 } 570 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 571 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 572 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 573 } 574 } 575 // Fill in signals that are blocked by all but the VM thread. 576 sigemptyset(&vm_sigs); 577 if (!ReduceSignalUsage) 578 sigaddset(&vm_sigs, BREAK_SIGNAL); 579 debug_only(signal_sets_initialized = true); 580 581 } 582 583 // These are signals that are unblocked while a thread is running Java. 584 // (For some reason, they get blocked by default.) 585 sigset_t* os::Linux::unblocked_signals() { 586 assert(signal_sets_initialized, "Not initialized"); 587 return &unblocked_sigs; 588 } 589 590 // These are the signals that are blocked while a (non-VM) thread is 591 // running Java. Only the VM thread handles these signals. 592 sigset_t* os::Linux::vm_signals() { 593 assert(signal_sets_initialized, "Not initialized"); 594 return &vm_sigs; 595 } 596 597 // These are signals that are blocked during cond_wait to allow debugger in 598 sigset_t* os::Linux::allowdebug_blocked_signals() { 599 assert(signal_sets_initialized, "Not initialized"); 600 return &allowdebug_blocked_sigs; 601 } 602 603 void os::Linux::hotspot_sigmask(Thread* thread) { 604 605 //Save caller's signal mask before setting VM signal mask 606 sigset_t caller_sigmask; 607 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 608 609 OSThread* osthread = thread->osthread(); 610 osthread->set_caller_sigmask(caller_sigmask); 611 612 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 613 614 if (!ReduceSignalUsage) { 615 if (thread->is_VM_thread()) { 616 // Only the VM thread handles BREAK_SIGNAL ... 617 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 618 } else { 619 // ... all other threads block BREAK_SIGNAL 620 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 621 } 622 } 623 } 624 625 ////////////////////////////////////////////////////////////////////////////// 626 // detecting pthread library 627 628 void os::Linux::libpthread_init() { 629 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION 630 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a 631 // generic name for earlier versions. 632 // Define macros here so we can build HotSpot on old systems. 633 # ifndef _CS_GNU_LIBC_VERSION 634 # define _CS_GNU_LIBC_VERSION 2 635 # endif 636 # ifndef _CS_GNU_LIBPTHREAD_VERSION 637 # define _CS_GNU_LIBPTHREAD_VERSION 3 638 # endif 639 640 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 641 if (n > 0) { 642 char *str = (char *)malloc(n); 643 confstr(_CS_GNU_LIBC_VERSION, str, n); 644 os::Linux::set_glibc_version(str); 645 } else { 646 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version() 647 static char _gnu_libc_version[32]; 648 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version), 649 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release()); 650 os::Linux::set_glibc_version(_gnu_libc_version); 651 } 652 653 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 654 if (n > 0) { 655 char *str = (char *)malloc(n); 656 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 657 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells 658 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this 659 // is the case. LinuxThreads has a hard limit on max number of threads. 660 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value. 661 // On the other hand, NPTL does not have such a limit, sysconf() 662 // will return -1 and errno is not changed. Check if it is really NPTL. 663 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 && 664 strstr(str, "NPTL") && 665 sysconf(_SC_THREAD_THREADS_MAX) > 0) { 666 free(str); 667 os::Linux::set_libpthread_version("linuxthreads"); 668 } else { 669 os::Linux::set_libpthread_version(str); 670 } 671 } else { 672 // glibc before 2.3.2 only has LinuxThreads. 673 os::Linux::set_libpthread_version("linuxthreads"); 674 } 675 676 if (strstr(libpthread_version(), "NPTL")) { 677 os::Linux::set_is_NPTL(); 678 } else { 679 os::Linux::set_is_LinuxThreads(); 680 } 681 682 // LinuxThreads have two flavors: floating-stack mode, which allows variable 683 // stack size; and fixed-stack mode. NPTL is always floating-stack. 684 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) { 685 os::Linux::set_is_floating_stack(); 686 } 687 } 688 689 ///////////////////////////////////////////////////////////////////////////// 690 // thread stack 691 692 // Force Linux kernel to expand current thread stack. If "bottom" is close 693 // to the stack guard, caller should block all signals. 694 // 695 // MAP_GROWSDOWN: 696 // A special mmap() flag that is used to implement thread stacks. It tells 697 // kernel that the memory region should extend downwards when needed. This 698 // allows early versions of LinuxThreads to only mmap the first few pages 699 // when creating a new thread. Linux kernel will automatically expand thread 700 // stack as needed (on page faults). 701 // 702 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 703 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 704 // region, it's hard to tell if the fault is due to a legitimate stack 705 // access or because of reading/writing non-exist memory (e.g. buffer 706 // overrun). As a rule, if the fault happens below current stack pointer, 707 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 708 // application (see Linux kernel fault.c). 709 // 710 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 711 // stack overflow detection. 712 // 713 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 714 // not use this flag. However, the stack of initial thread is not created 715 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though 716 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack 717 // and then attach the thread to JVM. 718 // 719 // To get around the problem and allow stack banging on Linux, we need to 720 // manually expand thread stack after receiving the SIGSEGV. 721 // 722 // There are two ways to expand thread stack to address "bottom", we used 723 // both of them in JVM before 1.5: 724 // 1. adjust stack pointer first so that it is below "bottom", and then 725 // touch "bottom" 726 // 2. mmap() the page in question 727 // 728 // Now alternate signal stack is gone, it's harder to use 2. For instance, 729 // if current sp is already near the lower end of page 101, and we need to 730 // call mmap() to map page 100, it is possible that part of the mmap() frame 731 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 732 // That will destroy the mmap() frame and cause VM to crash. 733 // 734 // The following code works by adjusting sp first, then accessing the "bottom" 735 // page to force a page fault. Linux kernel will then automatically expand the 736 // stack mapping. 737 // 738 // _expand_stack_to() assumes its frame size is less than page size, which 739 // should always be true if the function is not inlined. 740 741 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 742 #define NOINLINE 743 #else 744 #define NOINLINE __attribute__ ((noinline)) 745 #endif 746 747 static void _expand_stack_to(address bottom) NOINLINE; 748 749 static void _expand_stack_to(address bottom) { 750 address sp; 751 size_t size; 752 volatile char *p; 753 754 // Adjust bottom to point to the largest address within the same page, it 755 // gives us a one-page buffer if alloca() allocates slightly more memory. 756 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 757 bottom += os::Linux::page_size() - 1; 758 759 // sp might be slightly above current stack pointer; if that's the case, we 760 // will alloca() a little more space than necessary, which is OK. Don't use 761 // os::current_stack_pointer(), as its result can be slightly below current 762 // stack pointer, causing us to not alloca enough to reach "bottom". 763 sp = (address)&sp; 764 765 if (sp > bottom) { 766 size = sp - bottom; 767 p = (volatile char *)alloca(size); 768 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 769 p[0] = '\0'; 770 } 771 } 772 773 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 774 assert(t!=NULL, "just checking"); 775 assert(t->osthread()->expanding_stack(), "expand should be set"); 776 assert(t->stack_base() != NULL, "stack_base was not initialized"); 777 778 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 779 sigset_t mask_all, old_sigset; 780 sigfillset(&mask_all); 781 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 782 _expand_stack_to(addr); 783 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 784 return true; 785 } 786 return false; 787 } 788 789 ////////////////////////////////////////////////////////////////////////////// 790 // create new thread 791 792 static address highest_vm_reserved_address(); 793 794 // check if it's safe to start a new thread 795 static bool _thread_safety_check(Thread* thread) { 796 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) { 797 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat) 798 // Heap is mmap'ed at lower end of memory space. Thread stacks are 799 // allocated (MAP_FIXED) from high address space. Every thread stack 800 // occupies a fixed size slot (usually 2Mbytes, but user can change 801 // it to other values if they rebuild LinuxThreads). 802 // 803 // Problem with MAP_FIXED is that mmap() can still succeed even part of 804 // the memory region has already been mmap'ed. That means if we have too 805 // many threads and/or very large heap, eventually thread stack will 806 // collide with heap. 807 // 808 // Here we try to prevent heap/stack collision by comparing current 809 // stack bottom with the highest address that has been mmap'ed by JVM 810 // plus a safety margin for memory maps created by native code. 811 // 812 // This feature can be disabled by setting ThreadSafetyMargin to 0 813 // 814 if (ThreadSafetyMargin > 0) { 815 address stack_bottom = os::current_stack_base() - os::current_stack_size(); 816 817 // not safe if our stack extends below the safety margin 818 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address(); 819 } else { 820 return true; 821 } 822 } else { 823 // Floating stack LinuxThreads or NPTL: 824 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When 825 // there's not enough space left, pthread_create() will fail. If we come 826 // here, that means enough space has been reserved for stack. 827 return true; 828 } 829 } 830 831 // Thread start routine for all newly created threads 832 static void *java_start(Thread *thread) { 833 // Try to randomize the cache line index of hot stack frames. 834 // This helps when threads of the same stack traces evict each other's 835 // cache lines. The threads can be either from the same JVM instance, or 836 // from different JVM instances. The benefit is especially true for 837 // processors with hyperthreading technology. 838 static int counter = 0; 839 int pid = os::current_process_id(); 840 alloca(((pid ^ counter++) & 7) * 128); 841 842 ThreadLocalStorage::set_thread(thread); 843 844 OSThread* osthread = thread->osthread(); 845 Monitor* sync = osthread->startThread_lock(); 846 847 // non floating stack LinuxThreads needs extra check, see above 848 if (!_thread_safety_check(thread)) { 849 // notify parent thread 850 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 851 osthread->set_state(ZOMBIE); 852 sync->notify_all(); 853 return NULL; 854 } 855 856 // thread_id is kernel thread id (similar to Solaris LWP id) 857 osthread->set_thread_id(os::Linux::gettid()); 858 859 if (UseNUMA) { 860 int lgrp_id = os::numa_get_group_id(); 861 if (lgrp_id != -1) { 862 thread->set_lgrp_id(lgrp_id); 863 } 864 } 865 // initialize signal mask for this thread 866 os::Linux::hotspot_sigmask(thread); 867 868 // initialize floating point control register 869 os::Linux::init_thread_fpu_state(); 870 871 // handshaking with parent thread 872 { 873 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 874 875 // notify parent thread 876 osthread->set_state(INITIALIZED); 877 sync->notify_all(); 878 879 // wait until os::start_thread() 880 while (osthread->get_state() == INITIALIZED) { 881 sync->wait(Mutex::_no_safepoint_check_flag); 882 } 883 } 884 885 // call one more level start routine 886 thread->run(); 887 888 return 0; 889 } 890 891 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) { 892 assert(thread->osthread() == NULL, "caller responsible"); 893 894 // Allocate the OSThread object 895 OSThread* osthread = new OSThread(NULL, NULL); 896 if (osthread == NULL) { 897 return false; 898 } 899 900 // set the correct thread state 901 osthread->set_thread_type(thr_type); 902 903 // Initial state is ALLOCATED but not INITIALIZED 904 osthread->set_state(ALLOCATED); 905 906 thread->set_osthread(osthread); 907 908 // init thread attributes 909 pthread_attr_t attr; 910 pthread_attr_init(&attr); 911 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 912 913 // stack size 914 if (os::Linux::supports_variable_stack_size()) { 915 // calculate stack size if it's not specified by caller 916 if (stack_size == 0) { 917 stack_size = os::Linux::default_stack_size(thr_type); 918 919 switch (thr_type) { 920 case os::java_thread: 921 // Java threads use ThreadStackSize which default value can be 922 // changed with the flag -Xss 923 assert (JavaThread::stack_size_at_create() > 0, "this should be set"); 924 stack_size = JavaThread::stack_size_at_create(); 925 break; 926 case os::compiler_thread: 927 if (CompilerThreadStackSize > 0) { 928 stack_size = (size_t)(CompilerThreadStackSize * K); 929 break; 930 } // else fall through: 931 // use VMThreadStackSize if CompilerThreadStackSize is not defined 932 case os::vm_thread: 933 case os::pgc_thread: 934 case os::cgc_thread: 935 case os::watcher_thread: 936 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 937 break; 938 } 939 } 940 941 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 942 pthread_attr_setstacksize(&attr, stack_size); 943 } else { 944 // let pthread_create() pick the default value. 945 } 946 947 // glibc guard page 948 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 949 950 ThreadState state; 951 952 { 953 // Serialize thread creation if we are running with fixed stack LinuxThreads 954 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack(); 955 if (lock) { 956 os::Linux::createThread_lock()->lock_without_safepoint_check(); 957 } 958 959 pthread_t tid; 960 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 961 962 pthread_attr_destroy(&attr); 963 964 if (ret != 0) { 965 if (PrintMiscellaneous && (Verbose || WizardMode)) { 966 perror("pthread_create()"); 967 } 968 // Need to clean up stuff we've allocated so far 969 thread->set_osthread(NULL); 970 delete osthread; 971 if (lock) os::Linux::createThread_lock()->unlock(); 972 return false; 973 } 974 975 // Store pthread info into the OSThread 976 osthread->set_pthread_id(tid); 977 978 // Wait until child thread is either initialized or aborted 979 { 980 Monitor* sync_with_child = osthread->startThread_lock(); 981 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 982 while ((state = osthread->get_state()) == ALLOCATED) { 983 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 984 } 985 } 986 987 if (lock) { 988 os::Linux::createThread_lock()->unlock(); 989 } 990 } 991 992 // Aborted due to thread limit being reached 993 if (state == ZOMBIE) { 994 thread->set_osthread(NULL); 995 delete osthread; 996 return false; 997 } 998 999 // The thread is returned suspended (in state INITIALIZED), 1000 // and is started higher up in the call chain 1001 assert(state == INITIALIZED, "race condition"); 1002 return true; 1003 } 1004 1005 ///////////////////////////////////////////////////////////////////////////// 1006 // attach existing thread 1007 1008 // bootstrap the main thread 1009 bool os::create_main_thread(JavaThread* thread) { 1010 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 1011 return create_attached_thread(thread); 1012 } 1013 1014 bool os::create_attached_thread(JavaThread* thread) { 1015 #ifdef ASSERT 1016 thread->verify_not_published(); 1017 #endif 1018 1019 // Allocate the OSThread object 1020 OSThread* osthread = new OSThread(NULL, NULL); 1021 1022 if (osthread == NULL) { 1023 return false; 1024 } 1025 1026 // Store pthread info into the OSThread 1027 osthread->set_thread_id(os::Linux::gettid()); 1028 osthread->set_pthread_id(::pthread_self()); 1029 1030 // initialize floating point control register 1031 os::Linux::init_thread_fpu_state(); 1032 1033 // Initial thread state is RUNNABLE 1034 osthread->set_state(RUNNABLE); 1035 1036 thread->set_osthread(osthread); 1037 1038 if (UseNUMA) { 1039 int lgrp_id = os::numa_get_group_id(); 1040 if (lgrp_id != -1) { 1041 thread->set_lgrp_id(lgrp_id); 1042 } 1043 } 1044 1045 if (os::Linux::is_initial_thread()) { 1046 // If current thread is initial thread, its stack is mapped on demand, 1047 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 1048 // the entire stack region to avoid SEGV in stack banging. 1049 // It is also useful to get around the heap-stack-gap problem on SuSE 1050 // kernel (see 4821821 for details). We first expand stack to the top 1051 // of yellow zone, then enable stack yellow zone (order is significant, 1052 // enabling yellow zone first will crash JVM on SuSE Linux), so there 1053 // is no gap between the last two virtual memory regions. 1054 1055 JavaThread *jt = (JavaThread *)thread; 1056 address addr = jt->stack_yellow_zone_base(); 1057 assert(addr != NULL, "initialization problem?"); 1058 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 1059 1060 osthread->set_expanding_stack(); 1061 os::Linux::manually_expand_stack(jt, addr); 1062 osthread->clear_expanding_stack(); 1063 } 1064 1065 // initialize signal mask for this thread 1066 // and save the caller's signal mask 1067 os::Linux::hotspot_sigmask(thread); 1068 1069 return true; 1070 } 1071 1072 void os::pd_start_thread(Thread* thread) { 1073 OSThread * osthread = thread->osthread(); 1074 assert(osthread->get_state() != INITIALIZED, "just checking"); 1075 Monitor* sync_with_child = osthread->startThread_lock(); 1076 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 1077 sync_with_child->notify(); 1078 } 1079 1080 // Free Linux resources related to the OSThread 1081 void os::free_thread(OSThread* osthread) { 1082 assert(osthread != NULL, "osthread not set"); 1083 1084 if (Thread::current()->osthread() == osthread) { 1085 // Restore caller's signal mask 1086 sigset_t sigmask = osthread->caller_sigmask(); 1087 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1088 } 1089 1090 delete osthread; 1091 } 1092 1093 ////////////////////////////////////////////////////////////////////////////// 1094 // thread local storage 1095 1096 int os::allocate_thread_local_storage() { 1097 pthread_key_t key; 1098 int rslt = pthread_key_create(&key, NULL); 1099 assert(rslt == 0, "cannot allocate thread local storage"); 1100 return (int)key; 1101 } 1102 1103 // Note: This is currently not used by VM, as we don't destroy TLS key 1104 // on VM exit. 1105 void os::free_thread_local_storage(int index) { 1106 int rslt = pthread_key_delete((pthread_key_t)index); 1107 assert(rslt == 0, "invalid index"); 1108 } 1109 1110 void os::thread_local_storage_at_put(int index, void* value) { 1111 int rslt = pthread_setspecific((pthread_key_t)index, value); 1112 assert(rslt == 0, "pthread_setspecific failed"); 1113 } 1114 1115 extern "C" Thread* get_thread() { 1116 return ThreadLocalStorage::thread(); 1117 } 1118 1119 ////////////////////////////////////////////////////////////////////////////// 1120 // initial thread 1121 1122 // Check if current thread is the initial thread, similar to Solaris thr_main. 1123 bool os::Linux::is_initial_thread(void) { 1124 char dummy; 1125 // If called before init complete, thread stack bottom will be null. 1126 // Can be called if fatal error occurs before initialization. 1127 if (initial_thread_stack_bottom() == NULL) return false; 1128 assert(initial_thread_stack_bottom() != NULL && 1129 initial_thread_stack_size() != 0, 1130 "os::init did not locate initial thread's stack region"); 1131 if ((address)&dummy >= initial_thread_stack_bottom() && 1132 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) 1133 return true; 1134 else return false; 1135 } 1136 1137 // Find the virtual memory area that contains addr 1138 static bool find_vma(address addr, address* vma_low, address* vma_high) { 1139 FILE *fp = fopen("/proc/self/maps", "r"); 1140 if (fp) { 1141 address low, high; 1142 while (!feof(fp)) { 1143 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1144 if (low <= addr && addr < high) { 1145 if (vma_low) *vma_low = low; 1146 if (vma_high) *vma_high = high; 1147 fclose (fp); 1148 return true; 1149 } 1150 } 1151 for (;;) { 1152 int ch = fgetc(fp); 1153 if (ch == EOF || ch == (int)'\n') break; 1154 } 1155 } 1156 fclose(fp); 1157 } 1158 return false; 1159 } 1160 1161 // Locate initial thread stack. This special handling of initial thread stack 1162 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 1163 // bogus value for initial thread. 1164 void os::Linux::capture_initial_stack(size_t max_size) { 1165 // stack size is the easy part, get it from RLIMIT_STACK 1166 size_t stack_size; 1167 struct rlimit rlim; 1168 getrlimit(RLIMIT_STACK, &rlim); 1169 stack_size = rlim.rlim_cur; 1170 1171 // 6308388: a bug in ld.so will relocate its own .data section to the 1172 // lower end of primordial stack; reduce ulimit -s value a little bit 1173 // so we won't install guard page on ld.so's data section. 1174 stack_size -= 2 * page_size(); 1175 1176 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 1177 // 7.1, in both cases we will get 2G in return value. 1178 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 1179 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 1180 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 1181 // in case other parts in glibc still assumes 2M max stack size. 1182 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 1183 #ifndef IA64 1184 if (stack_size > 2 * K * K) stack_size = 2 * K * K; 1185 #else 1186 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 1187 if (stack_size > 4 * K * K) stack_size = 4 * K * K; 1188 #endif 1189 1190 // Try to figure out where the stack base (top) is. This is harder. 1191 // 1192 // When an application is started, glibc saves the initial stack pointer in 1193 // a global variable "__libc_stack_end", which is then used by system 1194 // libraries. __libc_stack_end should be pretty close to stack top. The 1195 // variable is available since the very early days. However, because it is 1196 // a private interface, it could disappear in the future. 1197 // 1198 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1199 // to __libc_stack_end, it is very close to stack top, but isn't the real 1200 // stack top. Note that /proc may not exist if VM is running as a chroot 1201 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1202 // /proc/<pid>/stat could change in the future (though unlikely). 1203 // 1204 // We try __libc_stack_end first. If that doesn't work, look for 1205 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1206 // as a hint, which should work well in most cases. 1207 1208 uintptr_t stack_start; 1209 1210 // try __libc_stack_end first 1211 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1212 if (p && *p) { 1213 stack_start = *p; 1214 } else { 1215 // see if we can get the start_stack field from /proc/self/stat 1216 FILE *fp; 1217 int pid; 1218 char state; 1219 int ppid; 1220 int pgrp; 1221 int session; 1222 int nr; 1223 int tpgrp; 1224 unsigned long flags; 1225 unsigned long minflt; 1226 unsigned long cminflt; 1227 unsigned long majflt; 1228 unsigned long cmajflt; 1229 unsigned long utime; 1230 unsigned long stime; 1231 long cutime; 1232 long cstime; 1233 long prio; 1234 long nice; 1235 long junk; 1236 long it_real; 1237 uintptr_t start; 1238 uintptr_t vsize; 1239 intptr_t rss; 1240 uintptr_t rsslim; 1241 uintptr_t scodes; 1242 uintptr_t ecode; 1243 int i; 1244 1245 // Figure what the primordial thread stack base is. Code is inspired 1246 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1247 // followed by command name surrounded by parentheses, state, etc. 1248 char stat[2048]; 1249 int statlen; 1250 1251 fp = fopen("/proc/self/stat", "r"); 1252 if (fp) { 1253 statlen = fread(stat, 1, 2047, fp); 1254 stat[statlen] = '\0'; 1255 fclose(fp); 1256 1257 // Skip pid and the command string. Note that we could be dealing with 1258 // weird command names, e.g. user could decide to rename java launcher 1259 // to "java 1.4.2 :)", then the stat file would look like 1260 // 1234 (java 1.4.2 :)) R ... ... 1261 // We don't really need to know the command string, just find the last 1262 // occurrence of ")" and then start parsing from there. See bug 4726580. 1263 char * s = strrchr(stat, ')'); 1264 1265 i = 0; 1266 if (s) { 1267 // Skip blank chars 1268 do s++; while (isspace(*s)); 1269 1270 #define _UFM UINTX_FORMAT 1271 #define _DFM INTX_FORMAT 1272 1273 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */ 1274 /* 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 */ 1275 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, 1276 &state, /* 3 %c */ 1277 &ppid, /* 4 %d */ 1278 &pgrp, /* 5 %d */ 1279 &session, /* 6 %d */ 1280 &nr, /* 7 %d */ 1281 &tpgrp, /* 8 %d */ 1282 &flags, /* 9 %lu */ 1283 &minflt, /* 10 %lu */ 1284 &cminflt, /* 11 %lu */ 1285 &majflt, /* 12 %lu */ 1286 &cmajflt, /* 13 %lu */ 1287 &utime, /* 14 %lu */ 1288 &stime, /* 15 %lu */ 1289 &cutime, /* 16 %ld */ 1290 &cstime, /* 17 %ld */ 1291 &prio, /* 18 %ld */ 1292 &nice, /* 19 %ld */ 1293 &junk, /* 20 %ld */ 1294 &it_real, /* 21 %ld */ 1295 &start, /* 22 UINTX_FORMAT */ 1296 &vsize, /* 23 UINTX_FORMAT */ 1297 &rss, /* 24 INTX_FORMAT */ 1298 &rsslim, /* 25 UINTX_FORMAT */ 1299 &scodes, /* 26 UINTX_FORMAT */ 1300 &ecode, /* 27 UINTX_FORMAT */ 1301 &stack_start); /* 28 UINTX_FORMAT */ 1302 } 1303 1304 #undef _UFM 1305 #undef _DFM 1306 1307 if (i != 28 - 2) { 1308 assert(false, "Bad conversion from /proc/self/stat"); 1309 // product mode - assume we are the initial thread, good luck in the 1310 // embedded case. 1311 warning("Can't detect initial thread stack location - bad conversion"); 1312 stack_start = (uintptr_t) &rlim; 1313 } 1314 } else { 1315 // For some reason we can't open /proc/self/stat (for example, running on 1316 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1317 // most cases, so don't abort: 1318 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1319 stack_start = (uintptr_t) &rlim; 1320 } 1321 } 1322 1323 // Now we have a pointer (stack_start) very close to the stack top, the 1324 // next thing to do is to figure out the exact location of stack top. We 1325 // can find out the virtual memory area that contains stack_start by 1326 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1327 // and its upper limit is the real stack top. (again, this would fail if 1328 // running inside chroot, because /proc may not exist.) 1329 1330 uintptr_t stack_top; 1331 address low, high; 1332 if (find_vma((address)stack_start, &low, &high)) { 1333 // success, "high" is the true stack top. (ignore "low", because initial 1334 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1335 stack_top = (uintptr_t)high; 1336 } else { 1337 // failed, likely because /proc/self/maps does not exist 1338 warning("Can't detect initial thread stack location - find_vma failed"); 1339 // best effort: stack_start is normally within a few pages below the real 1340 // stack top, use it as stack top, and reduce stack size so we won't put 1341 // guard page outside stack. 1342 stack_top = stack_start; 1343 stack_size -= 16 * page_size(); 1344 } 1345 1346 // stack_top could be partially down the page so align it 1347 stack_top = align_size_up(stack_top, page_size()); 1348 1349 if (max_size && stack_size > max_size) { 1350 _initial_thread_stack_size = max_size; 1351 } else { 1352 _initial_thread_stack_size = stack_size; 1353 } 1354 1355 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1356 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1357 } 1358 1359 //////////////////////////////////////////////////////////////////////////////// 1360 // time support 1361 1362 // Time since start-up in seconds to a fine granularity. 1363 // Used by VMSelfDestructTimer and the MemProfiler. 1364 double os::elapsedTime() { 1365 1366 return (double)(os::elapsed_counter()) * 0.000001; 1367 } 1368 1369 jlong os::elapsed_counter() { 1370 timeval time; 1371 int status = gettimeofday(&time, NULL); 1372 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count; 1373 } 1374 1375 jlong os::elapsed_frequency() { 1376 return (1000 * 1000); 1377 } 1378 1379 // For now, we say that linux does not support vtime. I have no idea 1380 // whether it can actually be made to (DLD, 9/13/05). 1381 1382 bool os::supports_vtime() { return false; } 1383 bool os::enable_vtime() { return false; } 1384 bool os::vtime_enabled() { return false; } 1385 double os::elapsedVTime() { 1386 // better than nothing, but not much 1387 return elapsedTime(); 1388 } 1389 1390 jlong os::javaTimeMillis() { 1391 timeval time; 1392 int status = gettimeofday(&time, NULL); 1393 assert(status != -1, "linux error"); 1394 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1395 } 1396 1397 #ifndef CLOCK_MONOTONIC 1398 #define CLOCK_MONOTONIC (1) 1399 #endif 1400 1401 void os::Linux::clock_init() { 1402 // we do dlopen's in this particular order due to bug in linux 1403 // dynamical loader (see 6348968) leading to crash on exit 1404 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1405 if (handle == NULL) { 1406 handle = dlopen("librt.so", RTLD_LAZY); 1407 } 1408 1409 if (handle) { 1410 int (*clock_getres_func)(clockid_t, struct timespec*) = 1411 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1412 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1413 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1414 if (clock_getres_func && clock_gettime_func) { 1415 // See if monotonic clock is supported by the kernel. Note that some 1416 // early implementations simply return kernel jiffies (updated every 1417 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1418 // for nano time (though the monotonic property is still nice to have). 1419 // It's fixed in newer kernels, however clock_getres() still returns 1420 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1421 // resolution for now. Hopefully as people move to new kernels, this 1422 // won't be a problem. 1423 struct timespec res; 1424 struct timespec tp; 1425 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1426 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1427 // yes, monotonic clock is supported 1428 _clock_gettime = clock_gettime_func; 1429 } else { 1430 // close librt if there is no monotonic clock 1431 dlclose(handle); 1432 } 1433 } 1434 } 1435 } 1436 1437 #ifndef SYS_clock_getres 1438 1439 #if defined(IA32) || defined(AMD64) 1440 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1441 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1442 #else 1443 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1444 #define sys_clock_getres(x,y) -1 1445 #endif 1446 1447 #else 1448 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1449 #endif 1450 1451 void os::Linux::fast_thread_clock_init() { 1452 if (!UseLinuxPosixThreadCPUClocks) { 1453 return; 1454 } 1455 clockid_t clockid; 1456 struct timespec tp; 1457 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1458 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1459 1460 // Switch to using fast clocks for thread cpu time if 1461 // the sys_clock_getres() returns 0 error code. 1462 // Note, that some kernels may support the current thread 1463 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1464 // returned by the pthread_getcpuclockid(). 1465 // If the fast Posix clocks are supported then the sys_clock_getres() 1466 // must return at least tp.tv_sec == 0 which means a resolution 1467 // better than 1 sec. This is extra check for reliability. 1468 1469 if(pthread_getcpuclockid_func && 1470 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1471 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1472 1473 _supports_fast_thread_cpu_time = true; 1474 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1475 } 1476 } 1477 1478 jlong os::javaTimeNanos() { 1479 if (Linux::supports_monotonic_clock()) { 1480 struct timespec tp; 1481 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1482 assert(status == 0, "gettime error"); 1483 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1484 return result; 1485 } else { 1486 timeval time; 1487 int status = gettimeofday(&time, NULL); 1488 assert(status != -1, "linux error"); 1489 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1490 return 1000 * usecs; 1491 } 1492 } 1493 1494 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1495 if (Linux::supports_monotonic_clock()) { 1496 info_ptr->max_value = ALL_64_BITS; 1497 1498 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1499 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1500 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1501 } else { 1502 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1503 info_ptr->max_value = ALL_64_BITS; 1504 1505 // gettimeofday is a real time clock so it skips 1506 info_ptr->may_skip_backward = true; 1507 info_ptr->may_skip_forward = true; 1508 } 1509 1510 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1511 } 1512 1513 // Return the real, user, and system times in seconds from an 1514 // arbitrary fixed point in the past. 1515 bool os::getTimesSecs(double* process_real_time, 1516 double* process_user_time, 1517 double* process_system_time) { 1518 struct tms ticks; 1519 clock_t real_ticks = times(&ticks); 1520 1521 if (real_ticks == (clock_t) (-1)) { 1522 return false; 1523 } else { 1524 double ticks_per_second = (double) clock_tics_per_sec; 1525 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1526 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1527 *process_real_time = ((double) real_ticks) / ticks_per_second; 1528 1529 return true; 1530 } 1531 } 1532 1533 1534 char * os::local_time_string(char *buf, size_t buflen) { 1535 struct tm t; 1536 time_t long_time; 1537 time(&long_time); 1538 localtime_r(&long_time, &t); 1539 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1540 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1541 t.tm_hour, t.tm_min, t.tm_sec); 1542 return buf; 1543 } 1544 1545 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1546 return localtime_r(clock, res); 1547 } 1548 1549 //////////////////////////////////////////////////////////////////////////////// 1550 // runtime exit support 1551 1552 // Note: os::shutdown() might be called very early during initialization, or 1553 // called from signal handler. Before adding something to os::shutdown(), make 1554 // sure it is async-safe and can handle partially initialized VM. 1555 void os::shutdown() { 1556 1557 // allow PerfMemory to attempt cleanup of any persistent resources 1558 perfMemory_exit(); 1559 1560 // needs to remove object in file system 1561 AttachListener::abort(); 1562 1563 // flush buffered output, finish log files 1564 ostream_abort(); 1565 1566 // Check for abort hook 1567 abort_hook_t abort_hook = Arguments::abort_hook(); 1568 if (abort_hook != NULL) { 1569 abort_hook(); 1570 } 1571 1572 } 1573 1574 // Note: os::abort() might be called very early during initialization, or 1575 // called from signal handler. Before adding something to os::abort(), make 1576 // sure it is async-safe and can handle partially initialized VM. 1577 void os::abort(bool dump_core) { 1578 os::shutdown(); 1579 if (dump_core) { 1580 #ifndef PRODUCT 1581 fdStream out(defaultStream::output_fd()); 1582 out.print_raw("Current thread is "); 1583 char buf[16]; 1584 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1585 out.print_raw_cr(buf); 1586 out.print_raw_cr("Dumping core ..."); 1587 #endif 1588 ::abort(); // dump core 1589 } 1590 1591 ::exit(1); 1592 } 1593 1594 // Die immediately, no exit hook, no abort hook, no cleanup. 1595 void os::die() { 1596 // _exit() on LinuxThreads only kills current thread 1597 ::abort(); 1598 } 1599 1600 // unused on linux for now. 1601 void os::set_error_file(const char *logfile) {} 1602 1603 1604 // This method is a copy of JDK's sysGetLastErrorString 1605 // from src/solaris/hpi/src/system_md.c 1606 1607 size_t os::lasterror(char *buf, size_t len) { 1608 1609 if (errno == 0) return 0; 1610 1611 const char *s = ::strerror(errno); 1612 size_t n = ::strlen(s); 1613 if (n >= len) { 1614 n = len - 1; 1615 } 1616 ::strncpy(buf, s, n); 1617 buf[n] = '\0'; 1618 return n; 1619 } 1620 1621 intx os::current_thread_id() { return (intx)pthread_self(); } 1622 int os::current_process_id() { 1623 1624 // Under the old linux thread library, linux gives each thread 1625 // its own process id. Because of this each thread will return 1626 // a different pid if this method were to return the result 1627 // of getpid(2). Linux provides no api that returns the pid 1628 // of the launcher thread for the vm. This implementation 1629 // returns a unique pid, the pid of the launcher thread 1630 // that starts the vm 'process'. 1631 1632 // Under the NPTL, getpid() returns the same pid as the 1633 // launcher thread rather than a unique pid per thread. 1634 // Use gettid() if you want the old pre NPTL behaviour. 1635 1636 // if you are looking for the result of a call to getpid() that 1637 // returns a unique pid for the calling thread, then look at the 1638 // OSThread::thread_id() method in osThread_linux.hpp file 1639 1640 return (int)(_initial_pid ? _initial_pid : getpid()); 1641 } 1642 1643 // DLL functions 1644 1645 const char* os::dll_file_extension() { return ".so"; } 1646 1647 // This must be hard coded because it's the system's temporary 1648 // directory not the java application's temp directory, ala java.io.tmpdir. 1649 const char* os::get_temp_directory() { return "/tmp"; } 1650 1651 static bool file_exists(const char* filename) { 1652 struct stat statbuf; 1653 if (filename == NULL || strlen(filename) == 0) { 1654 return false; 1655 } 1656 return os::stat(filename, &statbuf) == 0; 1657 } 1658 1659 void os::dll_build_name(char* buffer, size_t buflen, 1660 const char* pname, const char* fname) { 1661 // Copied from libhpi 1662 const size_t pnamelen = pname ? strlen(pname) : 0; 1663 1664 // Quietly truncate on buffer overflow. Should be an error. 1665 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1666 *buffer = '\0'; 1667 return; 1668 } 1669 1670 if (pnamelen == 0) { 1671 snprintf(buffer, buflen, "lib%s.so", fname); 1672 } else if (strchr(pname, *os::path_separator()) != NULL) { 1673 int n; 1674 char** pelements = split_path(pname, &n); 1675 for (int i = 0 ; i < n ; i++) { 1676 // Really shouldn't be NULL, but check can't hurt 1677 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1678 continue; // skip the empty path values 1679 } 1680 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1681 if (file_exists(buffer)) { 1682 break; 1683 } 1684 } 1685 // release the storage 1686 for (int i = 0 ; i < n ; i++) { 1687 if (pelements[i] != NULL) { 1688 FREE_C_HEAP_ARRAY(char, pelements[i]); 1689 } 1690 } 1691 if (pelements != NULL) { 1692 FREE_C_HEAP_ARRAY(char*, pelements); 1693 } 1694 } else { 1695 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1696 } 1697 } 1698 1699 const char* os::get_current_directory(char *buf, int buflen) { 1700 return getcwd(buf, buflen); 1701 } 1702 1703 // check if addr is inside libjvm[_g].so 1704 bool os::address_is_in_vm(address addr) { 1705 static address libjvm_base_addr; 1706 Dl_info dlinfo; 1707 1708 if (libjvm_base_addr == NULL) { 1709 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo); 1710 libjvm_base_addr = (address)dlinfo.dli_fbase; 1711 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1712 } 1713 1714 if (dladdr((void *)addr, &dlinfo)) { 1715 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1716 } 1717 1718 return false; 1719 } 1720 1721 bool os::dll_address_to_function_name(address addr, char *buf, 1722 int buflen, int *offset) { 1723 Dl_info dlinfo; 1724 1725 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) { 1726 if (buf != NULL) { 1727 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) { 1728 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1729 } 1730 } 1731 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1732 return true; 1733 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) { 1734 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1735 buf, buflen, offset, dlinfo.dli_fname)) { 1736 return true; 1737 } 1738 } 1739 1740 if (buf != NULL) buf[0] = '\0'; 1741 if (offset != NULL) *offset = -1; 1742 return false; 1743 } 1744 1745 struct _address_to_library_name { 1746 address addr; // input : memory address 1747 size_t buflen; // size of fname 1748 char* fname; // output: library name 1749 address base; // library base addr 1750 }; 1751 1752 static int address_to_library_name_callback(struct dl_phdr_info *info, 1753 size_t size, void *data) { 1754 int i; 1755 bool found = false; 1756 address libbase = NULL; 1757 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1758 1759 // iterate through all loadable segments 1760 for (i = 0; i < info->dlpi_phnum; i++) { 1761 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1762 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1763 // base address of a library is the lowest address of its loaded 1764 // segments. 1765 if (libbase == NULL || libbase > segbase) { 1766 libbase = segbase; 1767 } 1768 // see if 'addr' is within current segment 1769 if (segbase <= d->addr && 1770 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1771 found = true; 1772 } 1773 } 1774 } 1775 1776 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1777 // so dll_address_to_library_name() can fall through to use dladdr() which 1778 // can figure out executable name from argv[0]. 1779 if (found && info->dlpi_name && info->dlpi_name[0]) { 1780 d->base = libbase; 1781 if (d->fname) { 1782 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1783 } 1784 return 1; 1785 } 1786 return 0; 1787 } 1788 1789 bool os::dll_address_to_library_name(address addr, char* buf, 1790 int buflen, int* offset) { 1791 Dl_info dlinfo; 1792 struct _address_to_library_name data; 1793 1794 // There is a bug in old glibc dladdr() implementation that it could resolve 1795 // to wrong library name if the .so file has a base address != NULL. Here 1796 // we iterate through the program headers of all loaded libraries to find 1797 // out which library 'addr' really belongs to. This workaround can be 1798 // removed once the minimum requirement for glibc is moved to 2.3.x. 1799 data.addr = addr; 1800 data.fname = buf; 1801 data.buflen = buflen; 1802 data.base = NULL; 1803 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1804 1805 if (rslt) { 1806 // buf already contains library name 1807 if (offset) *offset = addr - data.base; 1808 return true; 1809 } else if (dladdr((void*)addr, &dlinfo)){ 1810 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1811 if (offset) *offset = addr - (address)dlinfo.dli_fbase; 1812 return true; 1813 } else { 1814 if (buf) buf[0] = '\0'; 1815 if (offset) *offset = -1; 1816 return false; 1817 } 1818 } 1819 1820 // Loads .dll/.so and 1821 // in case of error it checks if .dll/.so was built for the 1822 // same architecture as Hotspot is running on 1823 1824 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) 1825 { 1826 void * result= ::dlopen(filename, RTLD_LAZY); 1827 if (result != NULL) { 1828 // Successful loading 1829 return result; 1830 } 1831 1832 Elf32_Ehdr elf_head; 1833 1834 // Read system error message into ebuf 1835 // It may or may not be overwritten below 1836 ::strncpy(ebuf, ::dlerror(), ebuflen-1); 1837 ebuf[ebuflen-1]='\0'; 1838 int diag_msg_max_length=ebuflen-strlen(ebuf); 1839 char* diag_msg_buf=ebuf+strlen(ebuf); 1840 1841 if (diag_msg_max_length==0) { 1842 // No more space in ebuf for additional diagnostics message 1843 return NULL; 1844 } 1845 1846 1847 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1848 1849 if (file_descriptor < 0) { 1850 // Can't open library, report dlerror() message 1851 return NULL; 1852 } 1853 1854 bool failed_to_read_elf_head= 1855 (sizeof(elf_head)!= 1856 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ; 1857 1858 ::close(file_descriptor); 1859 if (failed_to_read_elf_head) { 1860 // file i/o error - report dlerror() msg 1861 return NULL; 1862 } 1863 1864 typedef struct { 1865 Elf32_Half code; // Actual value as defined in elf.h 1866 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1867 char elf_class; // 32 or 64 bit 1868 char endianess; // MSB or LSB 1869 char* name; // String representation 1870 } arch_t; 1871 1872 #ifndef EM_486 1873 #define EM_486 6 /* Intel 80486 */ 1874 #endif 1875 1876 static const arch_t arch_array[]={ 1877 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1878 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1879 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1880 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1881 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1882 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1883 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1884 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1885 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1886 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1887 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1888 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1889 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1890 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1891 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1892 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"} 1893 }; 1894 1895 #if (defined IA32) 1896 static Elf32_Half running_arch_code=EM_386; 1897 #elif (defined AMD64) 1898 static Elf32_Half running_arch_code=EM_X86_64; 1899 #elif (defined IA64) 1900 static Elf32_Half running_arch_code=EM_IA_64; 1901 #elif (defined __sparc) && (defined _LP64) 1902 static Elf32_Half running_arch_code=EM_SPARCV9; 1903 #elif (defined __sparc) && (!defined _LP64) 1904 static Elf32_Half running_arch_code=EM_SPARC; 1905 #elif (defined __powerpc64__) 1906 static Elf32_Half running_arch_code=EM_PPC64; 1907 #elif (defined __powerpc__) 1908 static Elf32_Half running_arch_code=EM_PPC; 1909 #elif (defined ARM) 1910 static Elf32_Half running_arch_code=EM_ARM; 1911 #elif (defined S390) 1912 static Elf32_Half running_arch_code=EM_S390; 1913 #elif (defined ALPHA) 1914 static Elf32_Half running_arch_code=EM_ALPHA; 1915 #elif (defined MIPSEL) 1916 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1917 #elif (defined PARISC) 1918 static Elf32_Half running_arch_code=EM_PARISC; 1919 #elif (defined MIPS) 1920 static Elf32_Half running_arch_code=EM_MIPS; 1921 #elif (defined M68K) 1922 static Elf32_Half running_arch_code=EM_68K; 1923 #else 1924 #error Method os::dll_load requires that one of following is defined:\ 1925 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K 1926 #endif 1927 1928 // Identify compatability class for VM's architecture and library's architecture 1929 // Obtain string descriptions for architectures 1930 1931 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1932 int running_arch_index=-1; 1933 1934 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) { 1935 if (running_arch_code == arch_array[i].code) { 1936 running_arch_index = i; 1937 } 1938 if (lib_arch.code == arch_array[i].code) { 1939 lib_arch.compat_class = arch_array[i].compat_class; 1940 lib_arch.name = arch_array[i].name; 1941 } 1942 } 1943 1944 assert(running_arch_index != -1, 1945 "Didn't find running architecture code (running_arch_code) in arch_array"); 1946 if (running_arch_index == -1) { 1947 // Even though running architecture detection failed 1948 // we may still continue with reporting dlerror() message 1949 return NULL; 1950 } 1951 1952 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1953 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1954 return NULL; 1955 } 1956 1957 #ifndef S390 1958 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1959 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1960 return NULL; 1961 } 1962 #endif // !S390 1963 1964 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1965 if ( lib_arch.name!=NULL ) { 1966 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1967 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1968 lib_arch.name, arch_array[running_arch_index].name); 1969 } else { 1970 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1971 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1972 lib_arch.code, 1973 arch_array[running_arch_index].name); 1974 } 1975 } 1976 1977 return NULL; 1978 } 1979 1980 /* 1981 * glibc-2.0 libdl is not MT safe. If you are building with any glibc, 1982 * chances are you might want to run the generated bits against glibc-2.0 1983 * libdl.so, so always use locking for any version of glibc. 1984 */ 1985 void* os::dll_lookup(void* handle, const char* name) { 1986 pthread_mutex_lock(&dl_mutex); 1987 void* res = dlsym(handle, name); 1988 pthread_mutex_unlock(&dl_mutex); 1989 return res; 1990 } 1991 1992 1993 static bool _print_ascii_file(const char* filename, outputStream* st) { 1994 int fd = ::open(filename, O_RDONLY); 1995 if (fd == -1) { 1996 return false; 1997 } 1998 1999 char buf[32]; 2000 int bytes; 2001 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 2002 st->print_raw(buf, bytes); 2003 } 2004 2005 ::close(fd); 2006 2007 return true; 2008 } 2009 2010 void os::print_dll_info(outputStream *st) { 2011 st->print_cr("Dynamic libraries:"); 2012 2013 char fname[32]; 2014 pid_t pid = os::Linux::gettid(); 2015 2016 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 2017 2018 if (!_print_ascii_file(fname, st)) { 2019 st->print("Can not get library information for pid = %d\n", pid); 2020 } 2021 } 2022 2023 void os::print_os_info_brief(outputStream* st) { 2024 os::Linux::print_distro_info(st); 2025 2026 os::Posix::print_uname_info(st); 2027 2028 os::Linux::print_libversion_info(st); 2029 2030 } 2031 2032 void os::print_os_info(outputStream* st) { 2033 st->print("OS:"); 2034 2035 os::Linux::print_distro_info(st); 2036 2037 os::Posix::print_uname_info(st); 2038 2039 // Print warning if unsafe chroot environment detected 2040 if (unsafe_chroot_detected) { 2041 st->print("WARNING!! "); 2042 st->print_cr(unstable_chroot_error); 2043 } 2044 2045 os::Linux::print_libversion_info(st); 2046 2047 os::Posix::print_rlimit_info(st); 2048 2049 os::Posix::print_load_average(st); 2050 2051 os::Linux::print_full_memory_info(st); 2052 } 2053 2054 // Try to identify popular distros. 2055 // Most Linux distributions have /etc/XXX-release file, which contains 2056 // the OS version string. Some have more than one /etc/XXX-release file 2057 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.), 2058 // so the order is important. 2059 void os::Linux::print_distro_info(outputStream* st) { 2060 if (!_print_ascii_file("/etc/mandrake-release", st) && 2061 !_print_ascii_file("/etc/sun-release", st) && 2062 !_print_ascii_file("/etc/redhat-release", st) && 2063 !_print_ascii_file("/etc/SuSE-release", st) && 2064 !_print_ascii_file("/etc/turbolinux-release", st) && 2065 !_print_ascii_file("/etc/gentoo-release", st) && 2066 !_print_ascii_file("/etc/debian_version", st) && 2067 !_print_ascii_file("/etc/ltib-release", st) && 2068 !_print_ascii_file("/etc/angstrom-version", st)) { 2069 st->print("Linux"); 2070 } 2071 st->cr(); 2072 } 2073 2074 void os::Linux::print_libversion_info(outputStream* st) { 2075 // libc, pthread 2076 st->print("libc:"); 2077 st->print(os::Linux::glibc_version()); st->print(" "); 2078 st->print(os::Linux::libpthread_version()); st->print(" "); 2079 if (os::Linux::is_LinuxThreads()) { 2080 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed"); 2081 } 2082 st->cr(); 2083 } 2084 2085 void os::Linux::print_full_memory_info(outputStream* st) { 2086 st->print("\n/proc/meminfo:\n"); 2087 _print_ascii_file("/proc/meminfo", st); 2088 st->cr(); 2089 } 2090 2091 void os::print_memory_info(outputStream* st) { 2092 2093 st->print("Memory:"); 2094 st->print(" %dk page", os::vm_page_size()>>10); 2095 2096 // values in struct sysinfo are "unsigned long" 2097 struct sysinfo si; 2098 sysinfo(&si); 2099 2100 st->print(", physical " UINT64_FORMAT "k", 2101 os::physical_memory() >> 10); 2102 st->print("(" UINT64_FORMAT "k free)", 2103 os::available_memory() >> 10); 2104 st->print(", swap " UINT64_FORMAT "k", 2105 ((jlong)si.totalswap * si.mem_unit) >> 10); 2106 st->print("(" UINT64_FORMAT "k free)", 2107 ((jlong)si.freeswap * si.mem_unit) >> 10); 2108 st->cr(); 2109 } 2110 2111 void os::pd_print_cpu_info(outputStream* st) { 2112 st->print("\n/proc/cpuinfo:\n"); 2113 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2114 st->print(" <Not Available>"); 2115 } 2116 st->cr(); 2117 } 2118 2119 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific 2120 // but they're the same for all the linux arch that we support 2121 // and they're the same for solaris but there's no common place to put this. 2122 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR", 2123 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG", 2124 "ILL_COPROC", "ILL_BADSTK" }; 2125 2126 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV", 2127 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES", 2128 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" }; 2129 2130 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" }; 2131 2132 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" }; 2133 2134 void os::print_siginfo(outputStream* st, void* siginfo) { 2135 st->print("siginfo:"); 2136 2137 const int buflen = 100; 2138 char buf[buflen]; 2139 siginfo_t *si = (siginfo_t*)siginfo; 2140 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen)); 2141 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) { 2142 st->print("si_errno=%s", buf); 2143 } else { 2144 st->print("si_errno=%d", si->si_errno); 2145 } 2146 const int c = si->si_code; 2147 assert(c > 0, "unexpected si_code"); 2148 switch (si->si_signo) { 2149 case SIGILL: 2150 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]); 2151 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2152 break; 2153 case SIGFPE: 2154 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]); 2155 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2156 break; 2157 case SIGSEGV: 2158 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]); 2159 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2160 break; 2161 case SIGBUS: 2162 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]); 2163 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2164 break; 2165 default: 2166 st->print(", si_code=%d", si->si_code); 2167 // no si_addr 2168 } 2169 2170 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2171 UseSharedSpaces) { 2172 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2173 if (mapinfo->is_in_shared_space(si->si_addr)) { 2174 st->print("\n\nError accessing class data sharing archive." \ 2175 " Mapped file inaccessible during execution, " \ 2176 " possible disk/network problem."); 2177 } 2178 } 2179 st->cr(); 2180 } 2181 2182 2183 static void print_signal_handler(outputStream* st, int sig, 2184 char* buf, size_t buflen); 2185 2186 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2187 st->print_cr("Signal Handlers:"); 2188 print_signal_handler(st, SIGSEGV, buf, buflen); 2189 print_signal_handler(st, SIGBUS , buf, buflen); 2190 print_signal_handler(st, SIGFPE , buf, buflen); 2191 print_signal_handler(st, SIGPIPE, buf, buflen); 2192 print_signal_handler(st, SIGXFSZ, buf, buflen); 2193 print_signal_handler(st, SIGILL , buf, buflen); 2194 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2195 print_signal_handler(st, SR_signum, buf, buflen); 2196 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2197 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2198 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2199 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2200 } 2201 2202 static char saved_jvm_path[MAXPATHLEN] = {0}; 2203 2204 // Find the full path to the current module, libjvm.so or libjvm_g.so 2205 void os::jvm_path(char *buf, jint buflen) { 2206 // Error checking. 2207 if (buflen < MAXPATHLEN) { 2208 assert(false, "must use a large-enough buffer"); 2209 buf[0] = '\0'; 2210 return; 2211 } 2212 // Lazy resolve the path to current module. 2213 if (saved_jvm_path[0] != 0) { 2214 strcpy(buf, saved_jvm_path); 2215 return; 2216 } 2217 2218 char dli_fname[MAXPATHLEN]; 2219 bool ret = dll_address_to_library_name( 2220 CAST_FROM_FN_PTR(address, os::jvm_path), 2221 dli_fname, sizeof(dli_fname), NULL); 2222 assert(ret != 0, "cannot locate libjvm"); 2223 char *rp = realpath(dli_fname, buf); 2224 if (rp == NULL) 2225 return; 2226 2227 if (Arguments::created_by_gamma_launcher()) { 2228 // Support for the gamma launcher. Typical value for buf is 2229 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at 2230 // the right place in the string, then assume we are installed in a JDK and 2231 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix 2232 // up the path so it looks like libjvm.so is installed there (append a 2233 // fake suffix hotspot/libjvm.so). 2234 const char *p = buf + strlen(buf) - 1; 2235 for (int count = 0; p > buf && count < 5; ++count) { 2236 for (--p; p > buf && *p != '/'; --p) 2237 /* empty */ ; 2238 } 2239 2240 if (strncmp(p, "/jre/lib/", 9) != 0) { 2241 // Look for JAVA_HOME in the environment. 2242 char* java_home_var = ::getenv("JAVA_HOME"); 2243 if (java_home_var != NULL && java_home_var[0] != 0) { 2244 char* jrelib_p; 2245 int len; 2246 2247 // Check the current module name "libjvm.so" or "libjvm_g.so". 2248 p = strrchr(buf, '/'); 2249 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2250 p = strstr(p, "_g") ? "_g" : ""; 2251 2252 rp = realpath(java_home_var, buf); 2253 if (rp == NULL) 2254 return; 2255 2256 // determine if this is a legacy image or modules image 2257 // modules image doesn't have "jre" subdirectory 2258 len = strlen(buf); 2259 jrelib_p = buf + len; 2260 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2261 if (0 != access(buf, F_OK)) { 2262 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2263 } 2264 2265 if (0 == access(buf, F_OK)) { 2266 // Use current module name "libjvm[_g].so" instead of 2267 // "libjvm"debug_only("_g")".so" since for fastdebug version 2268 // we should have "libjvm.so" but debug_only("_g") adds "_g"! 2269 len = strlen(buf); 2270 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p); 2271 } else { 2272 // Go back to path of .so 2273 rp = realpath(dli_fname, buf); 2274 if (rp == NULL) 2275 return; 2276 } 2277 } 2278 } 2279 } 2280 2281 strcpy(saved_jvm_path, buf); 2282 } 2283 2284 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2285 // no prefix required, not even "_" 2286 } 2287 2288 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2289 // no suffix required 2290 } 2291 2292 //////////////////////////////////////////////////////////////////////////////// 2293 // sun.misc.Signal support 2294 2295 static volatile jint sigint_count = 0; 2296 2297 static void 2298 UserHandler(int sig, void *siginfo, void *context) { 2299 // 4511530 - sem_post is serialized and handled by the manager thread. When 2300 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2301 // don't want to flood the manager thread with sem_post requests. 2302 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) 2303 return; 2304 2305 // Ctrl-C is pressed during error reporting, likely because the error 2306 // handler fails to abort. Let VM die immediately. 2307 if (sig == SIGINT && is_error_reported()) { 2308 os::die(); 2309 } 2310 2311 os::signal_notify(sig); 2312 } 2313 2314 void* os::user_handler() { 2315 return CAST_FROM_FN_PTR(void*, UserHandler); 2316 } 2317 2318 extern "C" { 2319 typedef void (*sa_handler_t)(int); 2320 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2321 } 2322 2323 void* os::signal(int signal_number, void* handler) { 2324 struct sigaction sigAct, oldSigAct; 2325 2326 sigfillset(&(sigAct.sa_mask)); 2327 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2328 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2329 2330 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2331 // -1 means registration failed 2332 return (void *)-1; 2333 } 2334 2335 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2336 } 2337 2338 void os::signal_raise(int signal_number) { 2339 ::raise(signal_number); 2340 } 2341 2342 /* 2343 * The following code is moved from os.cpp for making this 2344 * code platform specific, which it is by its very nature. 2345 */ 2346 2347 // Will be modified when max signal is changed to be dynamic 2348 int os::sigexitnum_pd() { 2349 return NSIG; 2350 } 2351 2352 // a counter for each possible signal value 2353 static volatile jint pending_signals[NSIG+1] = { 0 }; 2354 2355 // Linux(POSIX) specific hand shaking semaphore. 2356 static sem_t sig_sem; 2357 2358 void os::signal_init_pd() { 2359 // Initialize signal structures 2360 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2361 2362 // Initialize signal semaphore 2363 ::sem_init(&sig_sem, 0, 0); 2364 } 2365 2366 void os::signal_notify(int sig) { 2367 Atomic::inc(&pending_signals[sig]); 2368 ::sem_post(&sig_sem); 2369 } 2370 2371 static int check_pending_signals(bool wait) { 2372 Atomic::store(0, &sigint_count); 2373 for (;;) { 2374 for (int i = 0; i < NSIG + 1; i++) { 2375 jint n = pending_signals[i]; 2376 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2377 return i; 2378 } 2379 } 2380 if (!wait) { 2381 return -1; 2382 } 2383 JavaThread *thread = JavaThread::current(); 2384 ThreadBlockInVM tbivm(thread); 2385 2386 bool threadIsSuspended; 2387 do { 2388 thread->set_suspend_equivalent(); 2389 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2390 ::sem_wait(&sig_sem); 2391 2392 // were we externally suspended while we were waiting? 2393 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2394 if (threadIsSuspended) { 2395 // 2396 // The semaphore has been incremented, but while we were waiting 2397 // another thread suspended us. We don't want to continue running 2398 // while suspended because that would surprise the thread that 2399 // suspended us. 2400 // 2401 ::sem_post(&sig_sem); 2402 2403 thread->java_suspend_self(); 2404 } 2405 } while (threadIsSuspended); 2406 } 2407 } 2408 2409 int os::signal_lookup() { 2410 return check_pending_signals(false); 2411 } 2412 2413 int os::signal_wait() { 2414 return check_pending_signals(true); 2415 } 2416 2417 //////////////////////////////////////////////////////////////////////////////// 2418 // Virtual Memory 2419 2420 int os::vm_page_size() { 2421 // Seems redundant as all get out 2422 assert(os::Linux::page_size() != -1, "must call os::init"); 2423 return os::Linux::page_size(); 2424 } 2425 2426 // Solaris allocates memory by pages. 2427 int os::vm_allocation_granularity() { 2428 assert(os::Linux::page_size() != -1, "must call os::init"); 2429 return os::Linux::page_size(); 2430 } 2431 2432 // Rationale behind this function: 2433 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2434 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2435 // samples for JITted code. Here we create private executable mapping over the code cache 2436 // and then we can use standard (well, almost, as mapping can change) way to provide 2437 // info for the reporting script by storing timestamp and location of symbol 2438 void linux_wrap_code(char* base, size_t size) { 2439 static volatile jint cnt = 0; 2440 2441 if (!UseOprofile) { 2442 return; 2443 } 2444 2445 char buf[PATH_MAX+1]; 2446 int num = Atomic::add(1, &cnt); 2447 2448 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2449 os::get_temp_directory(), os::current_process_id(), num); 2450 unlink(buf); 2451 2452 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2453 2454 if (fd != -1) { 2455 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2456 if (rv != (off_t)-1) { 2457 if (::write(fd, "", 1) == 1) { 2458 mmap(base, size, 2459 PROT_READ|PROT_WRITE|PROT_EXEC, 2460 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2461 } 2462 } 2463 ::close(fd); 2464 unlink(buf); 2465 } 2466 } 2467 2468 // NOTE: Linux kernel does not really reserve the pages for us. 2469 // All it does is to check if there are enough free pages 2470 // left at the time of mmap(). This could be a potential 2471 // problem. 2472 bool os::commit_memory(char* addr, size_t size, bool exec) { 2473 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2474 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2475 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2476 if (res != (uintptr_t) MAP_FAILED) { 2477 if (UseNUMAInterleaving) { 2478 numa_make_global(addr, size); 2479 } 2480 return true; 2481 } 2482 return false; 2483 } 2484 2485 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2486 #ifndef MAP_HUGETLB 2487 #define MAP_HUGETLB 0x40000 2488 #endif 2489 2490 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2491 #ifndef MADV_HUGEPAGE 2492 #define MADV_HUGEPAGE 14 2493 #endif 2494 2495 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint, 2496 bool exec) { 2497 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) { 2498 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2499 uintptr_t res = 2500 (uintptr_t) ::mmap(addr, size, prot, 2501 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB, 2502 -1, 0); 2503 if (res != (uintptr_t) MAP_FAILED) { 2504 if (UseNUMAInterleaving) { 2505 numa_make_global(addr, size); 2506 } 2507 return true; 2508 } 2509 // Fall through and try to use small pages 2510 } 2511 2512 if (commit_memory(addr, size, exec)) { 2513 realign_memory(addr, size, alignment_hint); 2514 return true; 2515 } 2516 return false; 2517 } 2518 2519 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2520 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) { 2521 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2522 // be supported or the memory may already be backed by huge pages. 2523 ::madvise(addr, bytes, MADV_HUGEPAGE); 2524 } 2525 } 2526 2527 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2528 // This method works by doing an mmap over an existing mmaping and effectively discarding 2529 // the existing pages. However it won't work for SHM-based large pages that cannot be 2530 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2531 // small pages on top of the SHM segment. This method always works for small pages, so we 2532 // allow that in any case. 2533 if (alignment_hint <= (size_t)os::vm_page_size() || !UseSHM) { 2534 commit_memory(addr, bytes, alignment_hint, false); 2535 } 2536 } 2537 2538 void os::numa_make_global(char *addr, size_t bytes) { 2539 Linux::numa_interleave_memory(addr, bytes); 2540 } 2541 2542 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2543 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2544 } 2545 2546 bool os::numa_topology_changed() { return false; } 2547 2548 size_t os::numa_get_groups_num() { 2549 int max_node = Linux::numa_max_node(); 2550 return max_node > 0 ? max_node + 1 : 1; 2551 } 2552 2553 int os::numa_get_group_id() { 2554 int cpu_id = Linux::sched_getcpu(); 2555 if (cpu_id != -1) { 2556 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2557 if (lgrp_id != -1) { 2558 return lgrp_id; 2559 } 2560 } 2561 return 0; 2562 } 2563 2564 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2565 for (size_t i = 0; i < size; i++) { 2566 ids[i] = i; 2567 } 2568 return size; 2569 } 2570 2571 bool os::get_page_info(char *start, page_info* info) { 2572 return false; 2573 } 2574 2575 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) { 2576 return end; 2577 } 2578 2579 2580 int os::Linux::sched_getcpu_syscall(void) { 2581 unsigned int cpu; 2582 int retval = -1; 2583 2584 #if defined(IA32) 2585 # ifndef SYS_getcpu 2586 # define SYS_getcpu 318 2587 # endif 2588 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2589 #elif defined(AMD64) 2590 // Unfortunately we have to bring all these macros here from vsyscall.h 2591 // to be able to compile on old linuxes. 2592 # define __NR_vgetcpu 2 2593 # define VSYSCALL_START (-10UL << 20) 2594 # define VSYSCALL_SIZE 1024 2595 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2596 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2597 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2598 retval = vgetcpu(&cpu, NULL, NULL); 2599 #endif 2600 2601 return (retval == -1) ? retval : cpu; 2602 } 2603 2604 // Something to do with the numa-aware allocator needs these symbols 2605 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2606 extern "C" JNIEXPORT void numa_error(char *where) { } 2607 extern "C" JNIEXPORT int fork1() { return fork(); } 2608 2609 2610 // If we are running with libnuma version > 2, then we should 2611 // be trying to use symbols with versions 1.1 2612 // If we are running with earlier version, which did not have symbol versions, 2613 // we should use the base version. 2614 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2615 void *f = dlvsym(handle, name, "libnuma_1.1"); 2616 if (f == NULL) { 2617 f = dlsym(handle, name); 2618 } 2619 return f; 2620 } 2621 2622 bool os::Linux::libnuma_init() { 2623 // sched_getcpu() should be in libc. 2624 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2625 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2626 2627 // If it's not, try a direct syscall. 2628 if (sched_getcpu() == -1) 2629 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall)); 2630 2631 if (sched_getcpu() != -1) { // Does it work? 2632 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2633 if (handle != NULL) { 2634 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2635 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2636 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2637 libnuma_dlsym(handle, "numa_max_node"))); 2638 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2639 libnuma_dlsym(handle, "numa_available"))); 2640 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2641 libnuma_dlsym(handle, "numa_tonode_memory"))); 2642 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2643 libnuma_dlsym(handle, "numa_interleave_memory"))); 2644 2645 2646 if (numa_available() != -1) { 2647 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2648 // Create a cpu -> node mapping 2649 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true); 2650 rebuild_cpu_to_node_map(); 2651 return true; 2652 } 2653 } 2654 } 2655 return false; 2656 } 2657 2658 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2659 // The table is later used in get_node_by_cpu(). 2660 void os::Linux::rebuild_cpu_to_node_map() { 2661 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2662 // in libnuma (possible values are starting from 16, 2663 // and continuing up with every other power of 2, but less 2664 // than the maximum number of CPUs supported by kernel), and 2665 // is a subject to change (in libnuma version 2 the requirements 2666 // are more reasonable) we'll just hardcode the number they use 2667 // in the library. 2668 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2669 2670 size_t cpu_num = os::active_processor_count(); 2671 size_t cpu_map_size = NCPUS / BitsPerCLong; 2672 size_t cpu_map_valid_size = 2673 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2674 2675 cpu_to_node()->clear(); 2676 cpu_to_node()->at_grow(cpu_num - 1); 2677 size_t node_num = numa_get_groups_num(); 2678 2679 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size); 2680 for (size_t i = 0; i < node_num; i++) { 2681 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2682 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2683 if (cpu_map[j] != 0) { 2684 for (size_t k = 0; k < BitsPerCLong; k++) { 2685 if (cpu_map[j] & (1UL << k)) { 2686 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2687 } 2688 } 2689 } 2690 } 2691 } 2692 } 2693 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2694 } 2695 2696 int os::Linux::get_node_by_cpu(int cpu_id) { 2697 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2698 return cpu_to_node()->at(cpu_id); 2699 } 2700 return -1; 2701 } 2702 2703 GrowableArray<int>* os::Linux::_cpu_to_node; 2704 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2705 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2706 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2707 os::Linux::numa_available_func_t os::Linux::_numa_available; 2708 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2709 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2710 unsigned long* os::Linux::_numa_all_nodes; 2711 2712 bool os::uncommit_memory(char* addr, size_t size) { 2713 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2714 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2715 return res != (uintptr_t) MAP_FAILED; 2716 } 2717 2718 // Linux uses a growable mapping for the stack, and if the mapping for 2719 // the stack guard pages is not removed when we detach a thread the 2720 // stack cannot grow beyond the pages where the stack guard was 2721 // mapped. If at some point later in the process the stack expands to 2722 // that point, the Linux kernel cannot expand the stack any further 2723 // because the guard pages are in the way, and a segfault occurs. 2724 // 2725 // However, it's essential not to split the stack region by unmapping 2726 // a region (leaving a hole) that's already part of the stack mapping, 2727 // so if the stack mapping has already grown beyond the guard pages at 2728 // the time we create them, we have to truncate the stack mapping. 2729 // So, we need to know the extent of the stack mapping when 2730 // create_stack_guard_pages() is called. 2731 2732 // Find the bounds of the stack mapping. Return true for success. 2733 // 2734 // We only need this for stacks that are growable: at the time of 2735 // writing thread stacks don't use growable mappings (i.e. those 2736 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2737 // only applies to the main thread. 2738 2739 static 2740 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) { 2741 2742 char buf[128]; 2743 int fd, sz; 2744 2745 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) { 2746 return false; 2747 } 2748 2749 const char kw[] = "[stack]"; 2750 const int kwlen = sizeof(kw)-1; 2751 2752 // Address part of /proc/self/maps couldn't be more than 128 bytes 2753 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) { 2754 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) { 2755 // Extract addresses 2756 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) { 2757 uintptr_t sp = (uintptr_t) __builtin_frame_address(0); 2758 if (sp >= *bottom && sp <= *top) { 2759 ::close(fd); 2760 return true; 2761 } 2762 } 2763 } 2764 } 2765 2766 ::close(fd); 2767 return false; 2768 } 2769 2770 2771 // If the (growable) stack mapping already extends beyond the point 2772 // where we're going to put our guard pages, truncate the mapping at 2773 // that point by munmap()ping it. This ensures that when we later 2774 // munmap() the guard pages we don't leave a hole in the stack 2775 // mapping. This only affects the main/initial thread, but guard 2776 // against future OS changes 2777 bool os::create_stack_guard_pages(char* addr, size_t size) { 2778 uintptr_t stack_extent, stack_base; 2779 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2780 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2781 assert(os::Linux::is_initial_thread(), 2782 "growable stack in non-initial thread"); 2783 if (stack_extent < (uintptr_t)addr) 2784 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent); 2785 } 2786 2787 return os::commit_memory(addr, size); 2788 } 2789 2790 // If this is a growable mapping, remove the guard pages entirely by 2791 // munmap()ping them. If not, just call uncommit_memory(). This only 2792 // affects the main/initial thread, but guard against future OS changes 2793 bool os::remove_stack_guard_pages(char* addr, size_t size) { 2794 uintptr_t stack_extent, stack_base; 2795 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2796 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2797 assert(os::Linux::is_initial_thread(), 2798 "growable stack in non-initial thread"); 2799 2800 return ::munmap(addr, size) == 0; 2801 } 2802 2803 return os::uncommit_memory(addr, size); 2804 } 2805 2806 static address _highest_vm_reserved_address = NULL; 2807 2808 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 2809 // at 'requested_addr'. If there are existing memory mappings at the same 2810 // location, however, they will be overwritten. If 'fixed' is false, 2811 // 'requested_addr' is only treated as a hint, the return value may or 2812 // may not start from the requested address. Unlike Linux mmap(), this 2813 // function returns NULL to indicate failure. 2814 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 2815 char * addr; 2816 int flags; 2817 2818 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 2819 if (fixed) { 2820 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 2821 flags |= MAP_FIXED; 2822 } 2823 2824 // Map uncommitted pages PROT_READ and PROT_WRITE, change access 2825 // to PROT_EXEC if executable when we commit the page. 2826 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE, 2827 flags, -1, 0); 2828 2829 if (addr != MAP_FAILED) { 2830 // anon_mmap() should only get called during VM initialization, 2831 // don't need lock (actually we can skip locking even it can be called 2832 // from multiple threads, because _highest_vm_reserved_address is just a 2833 // hint about the upper limit of non-stack memory regions.) 2834 if ((address)addr + bytes > _highest_vm_reserved_address) { 2835 _highest_vm_reserved_address = (address)addr + bytes; 2836 } 2837 } 2838 2839 return addr == MAP_FAILED ? NULL : addr; 2840 } 2841 2842 // Don't update _highest_vm_reserved_address, because there might be memory 2843 // regions above addr + size. If so, releasing a memory region only creates 2844 // a hole in the address space, it doesn't help prevent heap-stack collision. 2845 // 2846 static int anon_munmap(char * addr, size_t size) { 2847 return ::munmap(addr, size) == 0; 2848 } 2849 2850 char* os::reserve_memory(size_t bytes, char* requested_addr, 2851 size_t alignment_hint) { 2852 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 2853 } 2854 2855 bool os::release_memory(char* addr, size_t size) { 2856 return anon_munmap(addr, size); 2857 } 2858 2859 static address highest_vm_reserved_address() { 2860 return _highest_vm_reserved_address; 2861 } 2862 2863 static bool linux_mprotect(char* addr, size_t size, int prot) { 2864 // Linux wants the mprotect address argument to be page aligned. 2865 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 2866 2867 // According to SUSv3, mprotect() should only be used with mappings 2868 // established by mmap(), and mmap() always maps whole pages. Unaligned 2869 // 'addr' likely indicates problem in the VM (e.g. trying to change 2870 // protection of malloc'ed or statically allocated memory). Check the 2871 // caller if you hit this assert. 2872 assert(addr == bottom, "sanity check"); 2873 2874 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 2875 return ::mprotect(bottom, size, prot) == 0; 2876 } 2877 2878 // Set protections specified 2879 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 2880 bool is_committed) { 2881 unsigned int p = 0; 2882 switch (prot) { 2883 case MEM_PROT_NONE: p = PROT_NONE; break; 2884 case MEM_PROT_READ: p = PROT_READ; break; 2885 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 2886 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 2887 default: 2888 ShouldNotReachHere(); 2889 } 2890 // is_committed is unused. 2891 return linux_mprotect(addr, bytes, p); 2892 } 2893 2894 bool os::guard_memory(char* addr, size_t size) { 2895 return linux_mprotect(addr, size, PROT_NONE); 2896 } 2897 2898 bool os::unguard_memory(char* addr, size_t size) { 2899 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 2900 } 2901 2902 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 2903 bool result = false; 2904 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE, 2905 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 2906 -1, 0); 2907 2908 if (p != (void *) -1) { 2909 // We don't know if this really is a huge page or not. 2910 FILE *fp = fopen("/proc/self/maps", "r"); 2911 if (fp) { 2912 while (!feof(fp)) { 2913 char chars[257]; 2914 long x = 0; 2915 if (fgets(chars, sizeof(chars), fp)) { 2916 if (sscanf(chars, "%lx-%*x", &x) == 1 2917 && x == (long)p) { 2918 if (strstr (chars, "hugepage")) { 2919 result = true; 2920 break; 2921 } 2922 } 2923 } 2924 } 2925 fclose(fp); 2926 } 2927 munmap (p, page_size); 2928 if (result) 2929 return true; 2930 } 2931 2932 if (warn) { 2933 warning("HugeTLBFS is not supported by the operating system."); 2934 } 2935 2936 return result; 2937 } 2938 2939 /* 2940 * Set the coredump_filter bits to include largepages in core dump (bit 6) 2941 * 2942 * From the coredump_filter documentation: 2943 * 2944 * - (bit 0) anonymous private memory 2945 * - (bit 1) anonymous shared memory 2946 * - (bit 2) file-backed private memory 2947 * - (bit 3) file-backed shared memory 2948 * - (bit 4) ELF header pages in file-backed private memory areas (it is 2949 * effective only if the bit 2 is cleared) 2950 * - (bit 5) hugetlb private memory 2951 * - (bit 6) hugetlb shared memory 2952 */ 2953 static void set_coredump_filter(void) { 2954 FILE *f; 2955 long cdm; 2956 2957 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 2958 return; 2959 } 2960 2961 if (fscanf(f, "%lx", &cdm) != 1) { 2962 fclose(f); 2963 return; 2964 } 2965 2966 rewind(f); 2967 2968 if ((cdm & LARGEPAGES_BIT) == 0) { 2969 cdm |= LARGEPAGES_BIT; 2970 fprintf(f, "%#lx", cdm); 2971 } 2972 2973 fclose(f); 2974 } 2975 2976 // Large page support 2977 2978 static size_t _large_page_size = 0; 2979 2980 void os::large_page_init() { 2981 if (!UseLargePages) { 2982 UseHugeTLBFS = false; 2983 UseSHM = false; 2984 return; 2985 } 2986 2987 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) { 2988 // If UseLargePages is specified on the command line try both methods, 2989 // if it's default, then try only HugeTLBFS. 2990 if (FLAG_IS_DEFAULT(UseLargePages)) { 2991 UseHugeTLBFS = true; 2992 } else { 2993 UseHugeTLBFS = UseSHM = true; 2994 } 2995 } 2996 2997 if (LargePageSizeInBytes) { 2998 _large_page_size = LargePageSizeInBytes; 2999 } else { 3000 // large_page_size on Linux is used to round up heap size. x86 uses either 3001 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3002 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3003 // page as large as 256M. 3004 // 3005 // Here we try to figure out page size by parsing /proc/meminfo and looking 3006 // for a line with the following format: 3007 // Hugepagesize: 2048 kB 3008 // 3009 // If we can't determine the value (e.g. /proc is not mounted, or the text 3010 // format has been changed), we'll use the largest page size supported by 3011 // the processor. 3012 3013 #ifndef ZERO 3014 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3015 ARM_ONLY(2 * M) PPC_ONLY(4 * M); 3016 #endif // ZERO 3017 3018 FILE *fp = fopen("/proc/meminfo", "r"); 3019 if (fp) { 3020 while (!feof(fp)) { 3021 int x = 0; 3022 char buf[16]; 3023 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3024 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3025 _large_page_size = x * K; 3026 break; 3027 } 3028 } else { 3029 // skip to next line 3030 for (;;) { 3031 int ch = fgetc(fp); 3032 if (ch == EOF || ch == (int)'\n') break; 3033 } 3034 } 3035 } 3036 fclose(fp); 3037 } 3038 } 3039 3040 // print a warning if any large page related flag is specified on command line 3041 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3042 3043 const size_t default_page_size = (size_t)Linux::page_size(); 3044 if (_large_page_size > default_page_size) { 3045 _page_sizes[0] = _large_page_size; 3046 _page_sizes[1] = default_page_size; 3047 _page_sizes[2] = 0; 3048 } 3049 UseHugeTLBFS = UseHugeTLBFS && 3050 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size); 3051 3052 if (UseHugeTLBFS) 3053 UseSHM = false; 3054 3055 UseLargePages = UseHugeTLBFS || UseSHM; 3056 3057 set_coredump_filter(); 3058 } 3059 3060 #ifndef SHM_HUGETLB 3061 #define SHM_HUGETLB 04000 3062 #endif 3063 3064 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) { 3065 // "exec" is passed in but not used. Creating the shared image for 3066 // the code cache doesn't have an SHM_X executable permission to check. 3067 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3068 3069 key_t key = IPC_PRIVATE; 3070 char *addr; 3071 3072 bool warn_on_failure = UseLargePages && 3073 (!FLAG_IS_DEFAULT(UseLargePages) || 3074 !FLAG_IS_DEFAULT(LargePageSizeInBytes) 3075 ); 3076 char msg[128]; 3077 3078 // Create a large shared memory region to attach to based on size. 3079 // Currently, size is the total size of the heap 3080 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3081 if (shmid == -1) { 3082 // Possible reasons for shmget failure: 3083 // 1. shmmax is too small for Java heap. 3084 // > check shmmax value: cat /proc/sys/kernel/shmmax 3085 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3086 // 2. not enough large page memory. 3087 // > check available large pages: cat /proc/meminfo 3088 // > increase amount of large pages: 3089 // echo new_value > /proc/sys/vm/nr_hugepages 3090 // Note 1: different Linux may use different name for this property, 3091 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3092 // Note 2: it's possible there's enough physical memory available but 3093 // they are so fragmented after a long run that they can't 3094 // coalesce into large pages. Try to reserve large pages when 3095 // the system is still "fresh". 3096 if (warn_on_failure) { 3097 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3098 warning(msg); 3099 } 3100 return NULL; 3101 } 3102 3103 // attach to the region 3104 addr = (char*)shmat(shmid, req_addr, 0); 3105 int err = errno; 3106 3107 // Remove shmid. If shmat() is successful, the actual shared memory segment 3108 // will be deleted when it's detached by shmdt() or when the process 3109 // terminates. If shmat() is not successful this will remove the shared 3110 // segment immediately. 3111 shmctl(shmid, IPC_RMID, NULL); 3112 3113 if ((intptr_t)addr == -1) { 3114 if (warn_on_failure) { 3115 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3116 warning(msg); 3117 } 3118 return NULL; 3119 } 3120 3121 if ((addr != NULL) && UseNUMAInterleaving) { 3122 numa_make_global(addr, bytes); 3123 } 3124 3125 return addr; 3126 } 3127 3128 bool os::release_memory_special(char* base, size_t bytes) { 3129 // detaching the SHM segment will also delete it, see reserve_memory_special() 3130 int rslt = shmdt(base); 3131 return rslt == 0; 3132 } 3133 3134 size_t os::large_page_size() { 3135 return _large_page_size; 3136 } 3137 3138 // HugeTLBFS allows application to commit large page memory on demand; 3139 // with SysV SHM the entire memory region must be allocated as shared 3140 // memory. 3141 bool os::can_commit_large_page_memory() { 3142 return UseHugeTLBFS; 3143 } 3144 3145 bool os::can_execute_large_page_memory() { 3146 return UseHugeTLBFS; 3147 } 3148 3149 // Reserve memory at an arbitrary address, only if that area is 3150 // available (and not reserved for something else). 3151 3152 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3153 const int max_tries = 10; 3154 char* base[max_tries]; 3155 size_t size[max_tries]; 3156 const size_t gap = 0x000000; 3157 3158 // Assert only that the size is a multiple of the page size, since 3159 // that's all that mmap requires, and since that's all we really know 3160 // about at this low abstraction level. If we need higher alignment, 3161 // we can either pass an alignment to this method or verify alignment 3162 // in one of the methods further up the call chain. See bug 5044738. 3163 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3164 3165 // Repeatedly allocate blocks until the block is allocated at the 3166 // right spot. Give up after max_tries. Note that reserve_memory() will 3167 // automatically update _highest_vm_reserved_address if the call is 3168 // successful. The variable tracks the highest memory address every reserved 3169 // by JVM. It is used to detect heap-stack collision if running with 3170 // fixed-stack LinuxThreads. Because here we may attempt to reserve more 3171 // space than needed, it could confuse the collision detecting code. To 3172 // solve the problem, save current _highest_vm_reserved_address and 3173 // calculate the correct value before return. 3174 address old_highest = _highest_vm_reserved_address; 3175 3176 // Linux mmap allows caller to pass an address as hint; give it a try first, 3177 // if kernel honors the hint then we can return immediately. 3178 char * addr = anon_mmap(requested_addr, bytes, false); 3179 if (addr == requested_addr) { 3180 return requested_addr; 3181 } 3182 3183 if (addr != NULL) { 3184 // mmap() is successful but it fails to reserve at the requested address 3185 anon_munmap(addr, bytes); 3186 } 3187 3188 int i; 3189 for (i = 0; i < max_tries; ++i) { 3190 base[i] = reserve_memory(bytes); 3191 3192 if (base[i] != NULL) { 3193 // Is this the block we wanted? 3194 if (base[i] == requested_addr) { 3195 size[i] = bytes; 3196 break; 3197 } 3198 3199 // Does this overlap the block we wanted? Give back the overlapped 3200 // parts and try again. 3201 3202 size_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3203 if (top_overlap >= 0 && top_overlap < bytes) { 3204 unmap_memory(base[i], top_overlap); 3205 base[i] += top_overlap; 3206 size[i] = bytes - top_overlap; 3207 } else { 3208 size_t bottom_overlap = base[i] + bytes - requested_addr; 3209 if (bottom_overlap >= 0 && bottom_overlap < bytes) { 3210 unmap_memory(requested_addr, bottom_overlap); 3211 size[i] = bytes - bottom_overlap; 3212 } else { 3213 size[i] = bytes; 3214 } 3215 } 3216 } 3217 } 3218 3219 // Give back the unused reserved pieces. 3220 3221 for (int j = 0; j < i; ++j) { 3222 if (base[j] != NULL) { 3223 unmap_memory(base[j], size[j]); 3224 } 3225 } 3226 3227 if (i < max_tries) { 3228 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes); 3229 return requested_addr; 3230 } else { 3231 _highest_vm_reserved_address = old_highest; 3232 return NULL; 3233 } 3234 } 3235 3236 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3237 return ::read(fd, buf, nBytes); 3238 } 3239 3240 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation. 3241 // Solaris uses poll(), linux uses park(). 3242 // Poll() is likely a better choice, assuming that Thread.interrupt() 3243 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with 3244 // SIGSEGV, see 4355769. 3245 3246 int os::sleep(Thread* thread, jlong millis, bool interruptible) { 3247 assert(thread == Thread::current(), "thread consistency check"); 3248 3249 ParkEvent * const slp = thread->_SleepEvent ; 3250 slp->reset() ; 3251 OrderAccess::fence() ; 3252 3253 if (interruptible) { 3254 jlong prevtime = javaTimeNanos(); 3255 3256 for (;;) { 3257 if (os::is_interrupted(thread, true)) { 3258 return OS_INTRPT; 3259 } 3260 3261 jlong newtime = javaTimeNanos(); 3262 3263 if (newtime - prevtime < 0) { 3264 // time moving backwards, should only happen if no monotonic clock 3265 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3266 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3267 } else { 3268 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 3269 } 3270 3271 if(millis <= 0) { 3272 return OS_OK; 3273 } 3274 3275 prevtime = newtime; 3276 3277 { 3278 assert(thread->is_Java_thread(), "sanity check"); 3279 JavaThread *jt = (JavaThread *) thread; 3280 ThreadBlockInVM tbivm(jt); 3281 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 3282 3283 jt->set_suspend_equivalent(); 3284 // cleared by handle_special_suspend_equivalent_condition() or 3285 // java_suspend_self() via check_and_wait_while_suspended() 3286 3287 slp->park(millis); 3288 3289 // were we externally suspended while we were waiting? 3290 jt->check_and_wait_while_suspended(); 3291 } 3292 } 3293 } else { 3294 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 3295 jlong prevtime = javaTimeNanos(); 3296 3297 for (;;) { 3298 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 3299 // the 1st iteration ... 3300 jlong newtime = javaTimeNanos(); 3301 3302 if (newtime - prevtime < 0) { 3303 // time moving backwards, should only happen if no monotonic clock 3304 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3305 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3306 } else { 3307 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 3308 } 3309 3310 if(millis <= 0) break ; 3311 3312 prevtime = newtime; 3313 slp->park(millis); 3314 } 3315 return OS_OK ; 3316 } 3317 } 3318 3319 int os::naked_sleep() { 3320 // %% make the sleep time an integer flag. for now use 1 millisec. 3321 return os::sleep(Thread::current(), 1, false); 3322 } 3323 3324 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3325 void os::infinite_sleep() { 3326 while (true) { // sleep forever ... 3327 ::sleep(100); // ... 100 seconds at a time 3328 } 3329 } 3330 3331 // Used to convert frequent JVM_Yield() to nops 3332 bool os::dont_yield() { 3333 return DontYieldALot; 3334 } 3335 3336 void os::yield() { 3337 sched_yield(); 3338 } 3339 3340 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;} 3341 3342 void os::yield_all(int attempts) { 3343 // Yields to all threads, including threads with lower priorities 3344 // Threads on Linux are all with same priority. The Solaris style 3345 // os::yield_all() with nanosleep(1ms) is not necessary. 3346 sched_yield(); 3347 } 3348 3349 // Called from the tight loops to possibly influence time-sharing heuristics 3350 void os::loop_breaker(int attempts) { 3351 os::yield_all(attempts); 3352 } 3353 3354 //////////////////////////////////////////////////////////////////////////////// 3355 // thread priority support 3356 3357 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3358 // only supports dynamic priority, static priority must be zero. For real-time 3359 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3360 // However, for large multi-threaded applications, SCHED_RR is not only slower 3361 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3362 // of 5 runs - Sep 2005). 3363 // 3364 // The following code actually changes the niceness of kernel-thread/LWP. It 3365 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3366 // not the entire user process, and user level threads are 1:1 mapped to kernel 3367 // threads. It has always been the case, but could change in the future. For 3368 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3369 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3370 3371 int os::java_to_os_priority[CriticalPriority + 1] = { 3372 19, // 0 Entry should never be used 3373 3374 4, // 1 MinPriority 3375 3, // 2 3376 2, // 3 3377 3378 1, // 4 3379 0, // 5 NormPriority 3380 -1, // 6 3381 3382 -2, // 7 3383 -3, // 8 3384 -4, // 9 NearMaxPriority 3385 3386 -5, // 10 MaxPriority 3387 3388 -5 // 11 CriticalPriority 3389 }; 3390 3391 static int prio_init() { 3392 if (ThreadPriorityPolicy == 1) { 3393 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3394 // if effective uid is not root. Perhaps, a more elegant way of doing 3395 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3396 if (geteuid() != 0) { 3397 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3398 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3399 } 3400 ThreadPriorityPolicy = 0; 3401 } 3402 } 3403 if (UseCriticalJavaThreadPriority) { 3404 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3405 } 3406 return 0; 3407 } 3408 3409 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3410 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK; 3411 3412 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3413 return (ret == 0) ? OS_OK : OS_ERR; 3414 } 3415 3416 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) { 3417 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) { 3418 *priority_ptr = java_to_os_priority[NormPriority]; 3419 return OS_OK; 3420 } 3421 3422 errno = 0; 3423 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3424 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3425 } 3426 3427 // Hint to the underlying OS that a task switch would not be good. 3428 // Void return because it's a hint and can fail. 3429 void os::hint_no_preempt() {} 3430 3431 //////////////////////////////////////////////////////////////////////////////// 3432 // suspend/resume support 3433 3434 // the low-level signal-based suspend/resume support is a remnant from the 3435 // old VM-suspension that used to be for java-suspension, safepoints etc, 3436 // within hotspot. Now there is a single use-case for this: 3437 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3438 // that runs in the watcher thread. 3439 // The remaining code is greatly simplified from the more general suspension 3440 // code that used to be used. 3441 // 3442 // The protocol is quite simple: 3443 // - suspend: 3444 // - sends a signal to the target thread 3445 // - polls the suspend state of the osthread using a yield loop 3446 // - target thread signal handler (SR_handler) sets suspend state 3447 // and blocks in sigsuspend until continued 3448 // - resume: 3449 // - sets target osthread state to continue 3450 // - sends signal to end the sigsuspend loop in the SR_handler 3451 // 3452 // Note that the SR_lock plays no role in this suspend/resume protocol. 3453 // 3454 3455 static void resume_clear_context(OSThread *osthread) { 3456 osthread->set_ucontext(NULL); 3457 osthread->set_siginfo(NULL); 3458 3459 // notify the suspend action is completed, we have now resumed 3460 osthread->sr.clear_suspended(); 3461 } 3462 3463 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) { 3464 osthread->set_ucontext(context); 3465 osthread->set_siginfo(siginfo); 3466 } 3467 3468 // 3469 // Handler function invoked when a thread's execution is suspended or 3470 // resumed. We have to be careful that only async-safe functions are 3471 // called here (Note: most pthread functions are not async safe and 3472 // should be avoided.) 3473 // 3474 // Note: sigwait() is a more natural fit than sigsuspend() from an 3475 // interface point of view, but sigwait() prevents the signal hander 3476 // from being run. libpthread would get very confused by not having 3477 // its signal handlers run and prevents sigwait()'s use with the 3478 // mutex granting granting signal. 3479 // 3480 // Currently only ever called on the VMThread 3481 // 3482 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3483 // Save and restore errno to avoid confusing native code with EINTR 3484 // after sigsuspend. 3485 int old_errno = errno; 3486 3487 Thread* thread = Thread::current(); 3488 OSThread* osthread = thread->osthread(); 3489 assert(thread->is_VM_thread(), "Must be VMThread"); 3490 // read current suspend action 3491 int action = osthread->sr.suspend_action(); 3492 if (action == SR_SUSPEND) { 3493 suspend_save_context(osthread, siginfo, context); 3494 3495 // Notify the suspend action is about to be completed. do_suspend() 3496 // waits until SR_SUSPENDED is set and then returns. We will wait 3497 // here for a resume signal and that completes the suspend-other 3498 // action. do_suspend/do_resume is always called as a pair from 3499 // the same thread - so there are no races 3500 3501 // notify the caller 3502 osthread->sr.set_suspended(); 3503 3504 sigset_t suspend_set; // signals for sigsuspend() 3505 3506 // get current set of blocked signals and unblock resume signal 3507 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3508 sigdelset(&suspend_set, SR_signum); 3509 3510 // wait here until we are resumed 3511 do { 3512 sigsuspend(&suspend_set); 3513 // ignore all returns until we get a resume signal 3514 } while (osthread->sr.suspend_action() != SR_CONTINUE); 3515 3516 resume_clear_context(osthread); 3517 3518 } else { 3519 assert(action == SR_CONTINUE, "unexpected sr action"); 3520 // nothing special to do - just leave the handler 3521 } 3522 3523 errno = old_errno; 3524 } 3525 3526 3527 static int SR_initialize() { 3528 struct sigaction act; 3529 char *s; 3530 /* Get signal number to use for suspend/resume */ 3531 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3532 int sig = ::strtol(s, 0, 10); 3533 if (sig > 0 || sig < _NSIG) { 3534 SR_signum = sig; 3535 } 3536 } 3537 3538 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 3539 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 3540 3541 sigemptyset(&SR_sigset); 3542 sigaddset(&SR_sigset, SR_signum); 3543 3544 /* Set up signal handler for suspend/resume */ 3545 act.sa_flags = SA_RESTART|SA_SIGINFO; 3546 act.sa_handler = (void (*)(int)) SR_handler; 3547 3548 // SR_signum is blocked by default. 3549 // 4528190 - We also need to block pthread restart signal (32 on all 3550 // supported Linux platforms). Note that LinuxThreads need to block 3551 // this signal for all threads to work properly. So we don't have 3552 // to use hard-coded signal number when setting up the mask. 3553 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 3554 3555 if (sigaction(SR_signum, &act, 0) == -1) { 3556 return -1; 3557 } 3558 3559 // Save signal flag 3560 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 3561 return 0; 3562 } 3563 3564 static int SR_finalize() { 3565 return 0; 3566 } 3567 3568 3569 // returns true on success and false on error - really an error is fatal 3570 // but this seems the normal response to library errors 3571 static bool do_suspend(OSThread* osthread) { 3572 // mark as suspended and send signal 3573 osthread->sr.set_suspend_action(SR_SUSPEND); 3574 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3575 assert_status(status == 0, status, "pthread_kill"); 3576 3577 // check status and wait until notified of suspension 3578 if (status == 0) { 3579 for (int i = 0; !osthread->sr.is_suspended(); i++) { 3580 os::yield_all(i); 3581 } 3582 osthread->sr.set_suspend_action(SR_NONE); 3583 return true; 3584 } 3585 else { 3586 osthread->sr.set_suspend_action(SR_NONE); 3587 return false; 3588 } 3589 } 3590 3591 static void do_resume(OSThread* osthread) { 3592 assert(osthread->sr.is_suspended(), "thread should be suspended"); 3593 osthread->sr.set_suspend_action(SR_CONTINUE); 3594 3595 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3596 assert_status(status == 0, status, "pthread_kill"); 3597 // check status and wait unit notified of resumption 3598 if (status == 0) { 3599 for (int i = 0; osthread->sr.is_suspended(); i++) { 3600 os::yield_all(i); 3601 } 3602 } 3603 osthread->sr.set_suspend_action(SR_NONE); 3604 } 3605 3606 //////////////////////////////////////////////////////////////////////////////// 3607 // interrupt support 3608 3609 void os::interrupt(Thread* thread) { 3610 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3611 "possibility of dangling Thread pointer"); 3612 3613 OSThread* osthread = thread->osthread(); 3614 3615 if (!osthread->interrupted()) { 3616 osthread->set_interrupted(true); 3617 // More than one thread can get here with the same value of osthread, 3618 // resulting in multiple notifications. We do, however, want the store 3619 // to interrupted() to be visible to other threads before we execute unpark(). 3620 OrderAccess::fence(); 3621 ParkEvent * const slp = thread->_SleepEvent ; 3622 if (slp != NULL) slp->unpark() ; 3623 } 3624 3625 // For JSR166. Unpark even if interrupt status already was set 3626 if (thread->is_Java_thread()) 3627 ((JavaThread*)thread)->parker()->unpark(); 3628 3629 ParkEvent * ev = thread->_ParkEvent ; 3630 if (ev != NULL) ev->unpark() ; 3631 3632 } 3633 3634 bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 3635 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3636 "possibility of dangling Thread pointer"); 3637 3638 OSThread* osthread = thread->osthread(); 3639 3640 bool interrupted = osthread->interrupted(); 3641 3642 if (interrupted && clear_interrupted) { 3643 osthread->set_interrupted(false); 3644 // consider thread->_SleepEvent->reset() ... optional optimization 3645 } 3646 3647 return interrupted; 3648 } 3649 3650 /////////////////////////////////////////////////////////////////////////////////// 3651 // signal handling (except suspend/resume) 3652 3653 // This routine may be used by user applications as a "hook" to catch signals. 3654 // The user-defined signal handler must pass unrecognized signals to this 3655 // routine, and if it returns true (non-zero), then the signal handler must 3656 // return immediately. If the flag "abort_if_unrecognized" is true, then this 3657 // routine will never retun false (zero), but instead will execute a VM panic 3658 // routine kill the process. 3659 // 3660 // If this routine returns false, it is OK to call it again. This allows 3661 // the user-defined signal handler to perform checks either before or after 3662 // the VM performs its own checks. Naturally, the user code would be making 3663 // a serious error if it tried to handle an exception (such as a null check 3664 // or breakpoint) that the VM was generating for its own correct operation. 3665 // 3666 // This routine may recognize any of the following kinds of signals: 3667 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 3668 // It should be consulted by handlers for any of those signals. 3669 // 3670 // The caller of this routine must pass in the three arguments supplied 3671 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 3672 // field of the structure passed to sigaction(). This routine assumes that 3673 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 3674 // 3675 // Note that the VM will print warnings if it detects conflicting signal 3676 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 3677 // 3678 extern "C" JNIEXPORT int 3679 JVM_handle_linux_signal(int signo, siginfo_t* siginfo, 3680 void* ucontext, int abort_if_unrecognized); 3681 3682 void signalHandler(int sig, siginfo_t* info, void* uc) { 3683 assert(info != NULL && uc != NULL, "it must be old kernel"); 3684 JVM_handle_linux_signal(sig, info, uc, true); 3685 } 3686 3687 3688 // This boolean allows users to forward their own non-matching signals 3689 // to JVM_handle_linux_signal, harmlessly. 3690 bool os::Linux::signal_handlers_are_installed = false; 3691 3692 // For signal-chaining 3693 struct sigaction os::Linux::sigact[MAXSIGNUM]; 3694 unsigned int os::Linux::sigs = 0; 3695 bool os::Linux::libjsig_is_loaded = false; 3696 typedef struct sigaction *(*get_signal_t)(int); 3697 get_signal_t os::Linux::get_signal_action = NULL; 3698 3699 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 3700 struct sigaction *actp = NULL; 3701 3702 if (libjsig_is_loaded) { 3703 // Retrieve the old signal handler from libjsig 3704 actp = (*get_signal_action)(sig); 3705 } 3706 if (actp == NULL) { 3707 // Retrieve the preinstalled signal handler from jvm 3708 actp = get_preinstalled_handler(sig); 3709 } 3710 3711 return actp; 3712 } 3713 3714 static bool call_chained_handler(struct sigaction *actp, int sig, 3715 siginfo_t *siginfo, void *context) { 3716 // Call the old signal handler 3717 if (actp->sa_handler == SIG_DFL) { 3718 // It's more reasonable to let jvm treat it as an unexpected exception 3719 // instead of taking the default action. 3720 return false; 3721 } else if (actp->sa_handler != SIG_IGN) { 3722 if ((actp->sa_flags & SA_NODEFER) == 0) { 3723 // automaticlly block the signal 3724 sigaddset(&(actp->sa_mask), sig); 3725 } 3726 3727 sa_handler_t hand; 3728 sa_sigaction_t sa; 3729 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 3730 // retrieve the chained handler 3731 if (siginfo_flag_set) { 3732 sa = actp->sa_sigaction; 3733 } else { 3734 hand = actp->sa_handler; 3735 } 3736 3737 if ((actp->sa_flags & SA_RESETHAND) != 0) { 3738 actp->sa_handler = SIG_DFL; 3739 } 3740 3741 // try to honor the signal mask 3742 sigset_t oset; 3743 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 3744 3745 // call into the chained handler 3746 if (siginfo_flag_set) { 3747 (*sa)(sig, siginfo, context); 3748 } else { 3749 (*hand)(sig); 3750 } 3751 3752 // restore the signal mask 3753 pthread_sigmask(SIG_SETMASK, &oset, 0); 3754 } 3755 // Tell jvm's signal handler the signal is taken care of. 3756 return true; 3757 } 3758 3759 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 3760 bool chained = false; 3761 // signal-chaining 3762 if (UseSignalChaining) { 3763 struct sigaction *actp = get_chained_signal_action(sig); 3764 if (actp != NULL) { 3765 chained = call_chained_handler(actp, sig, siginfo, context); 3766 } 3767 } 3768 return chained; 3769 } 3770 3771 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 3772 if ((( (unsigned int)1 << sig ) & sigs) != 0) { 3773 return &sigact[sig]; 3774 } 3775 return NULL; 3776 } 3777 3778 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 3779 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3780 sigact[sig] = oldAct; 3781 sigs |= (unsigned int)1 << sig; 3782 } 3783 3784 // for diagnostic 3785 int os::Linux::sigflags[MAXSIGNUM]; 3786 3787 int os::Linux::get_our_sigflags(int sig) { 3788 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3789 return sigflags[sig]; 3790 } 3791 3792 void os::Linux::set_our_sigflags(int sig, int flags) { 3793 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3794 sigflags[sig] = flags; 3795 } 3796 3797 void os::Linux::set_signal_handler(int sig, bool set_installed) { 3798 // Check for overwrite. 3799 struct sigaction oldAct; 3800 sigaction(sig, (struct sigaction*)NULL, &oldAct); 3801 3802 void* oldhand = oldAct.sa_sigaction 3803 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3804 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3805 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 3806 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 3807 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 3808 if (AllowUserSignalHandlers || !set_installed) { 3809 // Do not overwrite; user takes responsibility to forward to us. 3810 return; 3811 } else if (UseSignalChaining) { 3812 // save the old handler in jvm 3813 save_preinstalled_handler(sig, oldAct); 3814 // libjsig also interposes the sigaction() call below and saves the 3815 // old sigaction on it own. 3816 } else { 3817 fatal(err_msg("Encountered unexpected pre-existing sigaction handler " 3818 "%#lx for signal %d.", (long)oldhand, sig)); 3819 } 3820 } 3821 3822 struct sigaction sigAct; 3823 sigfillset(&(sigAct.sa_mask)); 3824 sigAct.sa_handler = SIG_DFL; 3825 if (!set_installed) { 3826 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3827 } else { 3828 sigAct.sa_sigaction = signalHandler; 3829 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3830 } 3831 // Save flags, which are set by ours 3832 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3833 sigflags[sig] = sigAct.sa_flags; 3834 3835 int ret = sigaction(sig, &sigAct, &oldAct); 3836 assert(ret == 0, "check"); 3837 3838 void* oldhand2 = oldAct.sa_sigaction 3839 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3840 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3841 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 3842 } 3843 3844 // install signal handlers for signals that HotSpot needs to 3845 // handle in order to support Java-level exception handling. 3846 3847 void os::Linux::install_signal_handlers() { 3848 if (!signal_handlers_are_installed) { 3849 signal_handlers_are_installed = true; 3850 3851 // signal-chaining 3852 typedef void (*signal_setting_t)(); 3853 signal_setting_t begin_signal_setting = NULL; 3854 signal_setting_t end_signal_setting = NULL; 3855 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3856 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 3857 if (begin_signal_setting != NULL) { 3858 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3859 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 3860 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 3861 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 3862 libjsig_is_loaded = true; 3863 assert(UseSignalChaining, "should enable signal-chaining"); 3864 } 3865 if (libjsig_is_loaded) { 3866 // Tell libjsig jvm is setting signal handlers 3867 (*begin_signal_setting)(); 3868 } 3869 3870 set_signal_handler(SIGSEGV, true); 3871 set_signal_handler(SIGPIPE, true); 3872 set_signal_handler(SIGBUS, true); 3873 set_signal_handler(SIGILL, true); 3874 set_signal_handler(SIGFPE, true); 3875 set_signal_handler(SIGXFSZ, true); 3876 3877 if (libjsig_is_loaded) { 3878 // Tell libjsig jvm finishes setting signal handlers 3879 (*end_signal_setting)(); 3880 } 3881 3882 // We don't activate signal checker if libjsig is in place, we trust ourselves 3883 // and if UserSignalHandler is installed all bets are off. 3884 // Log that signal checking is off only if -verbose:jni is specified. 3885 if (CheckJNICalls) { 3886 if (libjsig_is_loaded) { 3887 if (PrintJNIResolving) { 3888 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 3889 } 3890 check_signals = false; 3891 } 3892 if (AllowUserSignalHandlers) { 3893 if (PrintJNIResolving) { 3894 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 3895 } 3896 check_signals = false; 3897 } 3898 } 3899 } 3900 } 3901 3902 // This is the fastest way to get thread cpu time on Linux. 3903 // Returns cpu time (user+sys) for any thread, not only for current. 3904 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 3905 // It might work on 2.6.10+ with a special kernel/glibc patch. 3906 // For reference, please, see IEEE Std 1003.1-2004: 3907 // http://www.unix.org/single_unix_specification 3908 3909 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 3910 struct timespec tp; 3911 int rc = os::Linux::clock_gettime(clockid, &tp); 3912 assert(rc == 0, "clock_gettime is expected to return 0 code"); 3913 3914 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 3915 } 3916 3917 ///// 3918 // glibc on Linux platform uses non-documented flag 3919 // to indicate, that some special sort of signal 3920 // trampoline is used. 3921 // We will never set this flag, and we should 3922 // ignore this flag in our diagnostic 3923 #ifdef SIGNIFICANT_SIGNAL_MASK 3924 #undef SIGNIFICANT_SIGNAL_MASK 3925 #endif 3926 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 3927 3928 static const char* get_signal_handler_name(address handler, 3929 char* buf, int buflen) { 3930 int offset; 3931 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 3932 if (found) { 3933 // skip directory names 3934 const char *p1, *p2; 3935 p1 = buf; 3936 size_t len = strlen(os::file_separator()); 3937 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 3938 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 3939 } else { 3940 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 3941 } 3942 return buf; 3943 } 3944 3945 static void print_signal_handler(outputStream* st, int sig, 3946 char* buf, size_t buflen) { 3947 struct sigaction sa; 3948 3949 sigaction(sig, NULL, &sa); 3950 3951 // See comment for SIGNIFICANT_SIGNAL_MASK define 3952 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3953 3954 st->print("%s: ", os::exception_name(sig, buf, buflen)); 3955 3956 address handler = (sa.sa_flags & SA_SIGINFO) 3957 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 3958 : CAST_FROM_FN_PTR(address, sa.sa_handler); 3959 3960 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 3961 st->print("SIG_DFL"); 3962 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 3963 st->print("SIG_IGN"); 3964 } else { 3965 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 3966 } 3967 3968 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask); 3969 3970 address rh = VMError::get_resetted_sighandler(sig); 3971 // May be, handler was resetted by VMError? 3972 if(rh != NULL) { 3973 handler = rh; 3974 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 3975 } 3976 3977 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags); 3978 3979 // Check: is it our handler? 3980 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 3981 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 3982 // It is our signal handler 3983 // check for flags, reset system-used one! 3984 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 3985 st->print( 3986 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 3987 os::Linux::get_our_sigflags(sig)); 3988 } 3989 } 3990 st->cr(); 3991 } 3992 3993 3994 #define DO_SIGNAL_CHECK(sig) \ 3995 if (!sigismember(&check_signal_done, sig)) \ 3996 os::Linux::check_signal_handler(sig) 3997 3998 // This method is a periodic task to check for misbehaving JNI applications 3999 // under CheckJNI, we can add any periodic checks here 4000 4001 void os::run_periodic_checks() { 4002 4003 if (check_signals == false) return; 4004 4005 // SEGV and BUS if overridden could potentially prevent 4006 // generation of hs*.log in the event of a crash, debugging 4007 // such a case can be very challenging, so we absolutely 4008 // check the following for a good measure: 4009 DO_SIGNAL_CHECK(SIGSEGV); 4010 DO_SIGNAL_CHECK(SIGILL); 4011 DO_SIGNAL_CHECK(SIGFPE); 4012 DO_SIGNAL_CHECK(SIGBUS); 4013 DO_SIGNAL_CHECK(SIGPIPE); 4014 DO_SIGNAL_CHECK(SIGXFSZ); 4015 4016 4017 // ReduceSignalUsage allows the user to override these handlers 4018 // see comments at the very top and jvm_solaris.h 4019 if (!ReduceSignalUsage) { 4020 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4021 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4022 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4023 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4024 } 4025 4026 DO_SIGNAL_CHECK(SR_signum); 4027 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 4028 } 4029 4030 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4031 4032 static os_sigaction_t os_sigaction = NULL; 4033 4034 void os::Linux::check_signal_handler(int sig) { 4035 char buf[O_BUFLEN]; 4036 address jvmHandler = NULL; 4037 4038 4039 struct sigaction act; 4040 if (os_sigaction == NULL) { 4041 // only trust the default sigaction, in case it has been interposed 4042 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4043 if (os_sigaction == NULL) return; 4044 } 4045 4046 os_sigaction(sig, (struct sigaction*)NULL, &act); 4047 4048 4049 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4050 4051 address thisHandler = (act.sa_flags & SA_SIGINFO) 4052 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4053 : CAST_FROM_FN_PTR(address, act.sa_handler) ; 4054 4055 4056 switch(sig) { 4057 case SIGSEGV: 4058 case SIGBUS: 4059 case SIGFPE: 4060 case SIGPIPE: 4061 case SIGILL: 4062 case SIGXFSZ: 4063 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4064 break; 4065 4066 case SHUTDOWN1_SIGNAL: 4067 case SHUTDOWN2_SIGNAL: 4068 case SHUTDOWN3_SIGNAL: 4069 case BREAK_SIGNAL: 4070 jvmHandler = (address)user_handler(); 4071 break; 4072 4073 case INTERRUPT_SIGNAL: 4074 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 4075 break; 4076 4077 default: 4078 if (sig == SR_signum) { 4079 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4080 } else { 4081 return; 4082 } 4083 break; 4084 } 4085 4086 if (thisHandler != jvmHandler) { 4087 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4088 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4089 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4090 // No need to check this sig any longer 4091 sigaddset(&check_signal_done, sig); 4092 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4093 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4094 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 4095 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 4096 // No need to check this sig any longer 4097 sigaddset(&check_signal_done, sig); 4098 } 4099 4100 // Dump all the signal 4101 if (sigismember(&check_signal_done, sig)) { 4102 print_signal_handlers(tty, buf, O_BUFLEN); 4103 } 4104 } 4105 4106 extern void report_error(char* file_name, int line_no, char* title, char* format, ...); 4107 4108 extern bool signal_name(int signo, char* buf, size_t len); 4109 4110 const char* os::exception_name(int exception_code, char* buf, size_t size) { 4111 if (0 < exception_code && exception_code <= SIGRTMAX) { 4112 // signal 4113 if (!signal_name(exception_code, buf, size)) { 4114 jio_snprintf(buf, size, "SIG%d", exception_code); 4115 } 4116 return buf; 4117 } else { 4118 return NULL; 4119 } 4120 } 4121 4122 // this is called _before_ the most of global arguments have been parsed 4123 void os::init(void) { 4124 char dummy; /* used to get a guess on initial stack address */ 4125 // first_hrtime = gethrtime(); 4126 4127 // With LinuxThreads the JavaMain thread pid (primordial thread) 4128 // is different than the pid of the java launcher thread. 4129 // So, on Linux, the launcher thread pid is passed to the VM 4130 // via the sun.java.launcher.pid property. 4131 // Use this property instead of getpid() if it was correctly passed. 4132 // See bug 6351349. 4133 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid(); 4134 4135 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid(); 4136 4137 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4138 4139 init_random(1234567); 4140 4141 ThreadCritical::initialize(); 4142 4143 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4144 if (Linux::page_size() == -1) { 4145 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)", 4146 strerror(errno))); 4147 } 4148 init_page_sizes((size_t) Linux::page_size()); 4149 4150 Linux::initialize_system_info(); 4151 4152 // main_thread points to the aboriginal thread 4153 Linux::_main_thread = pthread_self(); 4154 4155 Linux::clock_init(); 4156 initial_time_count = os::elapsed_counter(); 4157 pthread_mutex_init(&dl_mutex, NULL); 4158 } 4159 4160 // To install functions for atexit system call 4161 extern "C" { 4162 static void perfMemory_exit_helper() { 4163 perfMemory_exit(); 4164 } 4165 } 4166 4167 // this is called _after_ the global arguments have been parsed 4168 jint os::init_2(void) 4169 { 4170 Linux::fast_thread_clock_init(); 4171 4172 // Allocate a single page and mark it as readable for safepoint polling 4173 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4174 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" ); 4175 4176 os::set_polling_page( polling_page ); 4177 4178 #ifndef PRODUCT 4179 if(Verbose && PrintMiscellaneous) 4180 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page); 4181 #endif 4182 4183 if (!UseMembar) { 4184 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4185 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page"); 4186 os::set_memory_serialize_page( mem_serialize_page ); 4187 4188 #ifndef PRODUCT 4189 if(Verbose && PrintMiscellaneous) 4190 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page); 4191 #endif 4192 } 4193 4194 os::large_page_init(); 4195 4196 // initialize suspend/resume support - must do this before signal_sets_init() 4197 if (SR_initialize() != 0) { 4198 perror("SR_initialize failed"); 4199 return JNI_ERR; 4200 } 4201 4202 Linux::signal_sets_init(); 4203 Linux::install_signal_handlers(); 4204 4205 // Check minimum allowable stack size for thread creation and to initialize 4206 // the java system classes, including StackOverflowError - depends on page 4207 // size. Add a page for compiler2 recursion in main thread. 4208 // Add in 2*BytesPerWord times page size to account for VM stack during 4209 // class initialization depending on 32 or 64 bit VM. 4210 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4211 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+ 4212 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size()); 4213 4214 size_t threadStackSizeInBytes = ThreadStackSize * K; 4215 if (threadStackSizeInBytes != 0 && 4216 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4217 tty->print_cr("\nThe stack size specified is too small, " 4218 "Specify at least %dk", 4219 os::Linux::min_stack_allowed/ K); 4220 return JNI_ERR; 4221 } 4222 4223 // Make the stack size a multiple of the page size so that 4224 // the yellow/red zones can be guarded. 4225 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4226 vm_page_size())); 4227 4228 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4229 4230 Linux::libpthread_init(); 4231 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4232 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n", 4233 Linux::glibc_version(), Linux::libpthread_version(), 4234 Linux::is_floating_stack() ? "floating stack" : "fixed stack"); 4235 } 4236 4237 if (UseNUMA) { 4238 if (!Linux::libnuma_init()) { 4239 UseNUMA = false; 4240 } else { 4241 if ((Linux::numa_max_node() < 1)) { 4242 // There's only one node(they start from 0), disable NUMA. 4243 UseNUMA = false; 4244 } 4245 } 4246 // With SHM large pages we cannot uncommit a page, so there's not way 4247 // we can make the adaptive lgrp chunk resizing work. If the user specified 4248 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and 4249 // disable adaptive resizing. 4250 if (UseNUMA && UseLargePages && UseSHM) { 4251 if (!FLAG_IS_DEFAULT(UseNUMA)) { 4252 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) { 4253 UseLargePages = false; 4254 } else { 4255 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing"); 4256 UseAdaptiveSizePolicy = false; 4257 UseAdaptiveNUMAChunkSizing = false; 4258 } 4259 } else { 4260 UseNUMA = false; 4261 } 4262 } 4263 if (!UseNUMA && ForceNUMA) { 4264 UseNUMA = true; 4265 } 4266 } 4267 4268 if (MaxFDLimit) { 4269 // set the number of file descriptors to max. print out error 4270 // if getrlimit/setrlimit fails but continue regardless. 4271 struct rlimit nbr_files; 4272 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4273 if (status != 0) { 4274 if (PrintMiscellaneous && (Verbose || WizardMode)) 4275 perror("os::init_2 getrlimit failed"); 4276 } else { 4277 nbr_files.rlim_cur = nbr_files.rlim_max; 4278 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4279 if (status != 0) { 4280 if (PrintMiscellaneous && (Verbose || WizardMode)) 4281 perror("os::init_2 setrlimit failed"); 4282 } 4283 } 4284 } 4285 4286 // Initialize lock used to serialize thread creation (see os::create_thread) 4287 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4288 4289 // at-exit methods are called in the reverse order of their registration. 4290 // atexit functions are called on return from main or as a result of a 4291 // call to exit(3C). There can be only 32 of these functions registered 4292 // and atexit() does not set errno. 4293 4294 if (PerfAllowAtExitRegistration) { 4295 // only register atexit functions if PerfAllowAtExitRegistration is set. 4296 // atexit functions can be delayed until process exit time, which 4297 // can be problematic for embedded VM situations. Embedded VMs should 4298 // call DestroyJavaVM() to assure that VM resources are released. 4299 4300 // note: perfMemory_exit_helper atexit function may be removed in 4301 // the future if the appropriate cleanup code can be added to the 4302 // VM_Exit VMOperation's doit method. 4303 if (atexit(perfMemory_exit_helper) != 0) { 4304 warning("os::init2 atexit(perfMemory_exit_helper) failed"); 4305 } 4306 } 4307 4308 // initialize thread priority policy 4309 prio_init(); 4310 4311 return JNI_OK; 4312 } 4313 4314 // this is called at the end of vm_initialization 4315 void os::init_3(void) 4316 { 4317 #ifdef JAVASE_EMBEDDED 4318 // Start the MemNotifyThread 4319 if (LowMemoryProtection) { 4320 MemNotifyThread::start(); 4321 } 4322 return; 4323 #endif 4324 } 4325 4326 // Mark the polling page as unreadable 4327 void os::make_polling_page_unreadable(void) { 4328 if( !guard_memory((char*)_polling_page, Linux::page_size()) ) 4329 fatal("Could not disable polling page"); 4330 }; 4331 4332 // Mark the polling page as readable 4333 void os::make_polling_page_readable(void) { 4334 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4335 fatal("Could not enable polling page"); 4336 } 4337 }; 4338 4339 int os::active_processor_count() { 4340 // Linux doesn't yet have a (official) notion of processor sets, 4341 // so just return the number of online processors. 4342 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4343 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4344 return online_cpus; 4345 } 4346 4347 void os::set_native_thread_name(const char *name) { 4348 // Not yet implemented. 4349 return; 4350 } 4351 4352 bool os::distribute_processes(uint length, uint* distribution) { 4353 // Not yet implemented. 4354 return false; 4355 } 4356 4357 bool os::bind_to_processor(uint processor_id) { 4358 // Not yet implemented. 4359 return false; 4360 } 4361 4362 /// 4363 4364 // Suspends the target using the signal mechanism and then grabs the PC before 4365 // resuming the target. Used by the flat-profiler only 4366 ExtendedPC os::get_thread_pc(Thread* thread) { 4367 // Make sure that it is called by the watcher for the VMThread 4368 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4369 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4370 4371 ExtendedPC epc; 4372 4373 OSThread* osthread = thread->osthread(); 4374 if (do_suspend(osthread)) { 4375 if (osthread->ucontext() != NULL) { 4376 epc = os::Linux::ucontext_get_pc(osthread->ucontext()); 4377 } else { 4378 // NULL context is unexpected, double-check this is the VMThread 4379 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4380 } 4381 do_resume(osthread); 4382 } 4383 // failure means pthread_kill failed for some reason - arguably this is 4384 // a fatal problem, but such problems are ignored elsewhere 4385 4386 return epc; 4387 } 4388 4389 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime) 4390 { 4391 if (is_NPTL()) { 4392 return pthread_cond_timedwait(_cond, _mutex, _abstime); 4393 } else { 4394 #ifndef IA64 4395 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control 4396 // word back to default 64bit precision if condvar is signaled. Java 4397 // wants 53bit precision. Save and restore current value. 4398 int fpu = get_fpu_control_word(); 4399 #endif // IA64 4400 int status = pthread_cond_timedwait(_cond, _mutex, _abstime); 4401 #ifndef IA64 4402 set_fpu_control_word(fpu); 4403 #endif // IA64 4404 return status; 4405 } 4406 } 4407 4408 //////////////////////////////////////////////////////////////////////////////// 4409 // debug support 4410 4411 static address same_page(address x, address y) { 4412 int page_bits = -os::vm_page_size(); 4413 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits)) 4414 return x; 4415 else if (x > y) 4416 return (address)(intptr_t(y) | ~page_bits) + 1; 4417 else 4418 return (address)(intptr_t(y) & page_bits); 4419 } 4420 4421 bool os::find(address addr, outputStream* st) { 4422 Dl_info dlinfo; 4423 memset(&dlinfo, 0, sizeof(dlinfo)); 4424 if (dladdr(addr, &dlinfo)) { 4425 st->print(PTR_FORMAT ": ", addr); 4426 if (dlinfo.dli_sname != NULL) { 4427 st->print("%s+%#x", dlinfo.dli_sname, 4428 addr - (intptr_t)dlinfo.dli_saddr); 4429 } else if (dlinfo.dli_fname) { 4430 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 4431 } else { 4432 st->print("<absolute address>"); 4433 } 4434 if (dlinfo.dli_fname) { 4435 st->print(" in %s", dlinfo.dli_fname); 4436 } 4437 if (dlinfo.dli_fbase) { 4438 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 4439 } 4440 st->cr(); 4441 4442 if (Verbose) { 4443 // decode some bytes around the PC 4444 address begin = same_page(addr-40, addr); 4445 address end = same_page(addr+40, addr); 4446 address lowest = (address) dlinfo.dli_sname; 4447 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4448 if (begin < lowest) begin = lowest; 4449 Dl_info dlinfo2; 4450 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr 4451 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) 4452 end = (address) dlinfo2.dli_saddr; 4453 Disassembler::decode(begin, end, st); 4454 } 4455 return true; 4456 } 4457 return false; 4458 } 4459 4460 //////////////////////////////////////////////////////////////////////////////// 4461 // misc 4462 4463 // This does not do anything on Linux. This is basically a hook for being 4464 // able to use structured exception handling (thread-local exception filters) 4465 // on, e.g., Win32. 4466 void 4467 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 4468 JavaCallArguments* args, Thread* thread) { 4469 f(value, method, args, thread); 4470 } 4471 4472 void os::print_statistics() { 4473 } 4474 4475 int os::message_box(const char* title, const char* message) { 4476 int i; 4477 fdStream err(defaultStream::error_fd()); 4478 for (i = 0; i < 78; i++) err.print_raw("="); 4479 err.cr(); 4480 err.print_raw_cr(title); 4481 for (i = 0; i < 78; i++) err.print_raw("-"); 4482 err.cr(); 4483 err.print_raw_cr(message); 4484 for (i = 0; i < 78; i++) err.print_raw("="); 4485 err.cr(); 4486 4487 char buf[16]; 4488 // Prevent process from exiting upon "read error" without consuming all CPU 4489 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4490 4491 return buf[0] == 'y' || buf[0] == 'Y'; 4492 } 4493 4494 int os::stat(const char *path, struct stat *sbuf) { 4495 char pathbuf[MAX_PATH]; 4496 if (strlen(path) > MAX_PATH - 1) { 4497 errno = ENAMETOOLONG; 4498 return -1; 4499 } 4500 os::native_path(strcpy(pathbuf, path)); 4501 return ::stat(pathbuf, sbuf); 4502 } 4503 4504 bool os::check_heap(bool force) { 4505 return true; 4506 } 4507 4508 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) { 4509 return ::vsnprintf(buf, count, format, args); 4510 } 4511 4512 // Is a (classpath) directory empty? 4513 bool os::dir_is_empty(const char* path) { 4514 DIR *dir = NULL; 4515 struct dirent *ptr; 4516 4517 dir = opendir(path); 4518 if (dir == NULL) return true; 4519 4520 /* Scan the directory */ 4521 bool result = true; 4522 char buf[sizeof(struct dirent) + MAX_PATH]; 4523 while (result && (ptr = ::readdir(dir)) != NULL) { 4524 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 4525 result = false; 4526 } 4527 } 4528 closedir(dir); 4529 return result; 4530 } 4531 4532 // This code originates from JDK's sysOpen and open64_w 4533 // from src/solaris/hpi/src/system_md.c 4534 4535 #ifndef O_DELETE 4536 #define O_DELETE 0x10000 4537 #endif 4538 4539 // Open a file. Unlink the file immediately after open returns 4540 // if the specified oflag has the O_DELETE flag set. 4541 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c 4542 4543 int os::open(const char *path, int oflag, int mode) { 4544 4545 if (strlen(path) > MAX_PATH - 1) { 4546 errno = ENAMETOOLONG; 4547 return -1; 4548 } 4549 int fd; 4550 int o_delete = (oflag & O_DELETE); 4551 oflag = oflag & ~O_DELETE; 4552 4553 fd = ::open64(path, oflag, mode); 4554 if (fd == -1) return -1; 4555 4556 //If the open succeeded, the file might still be a directory 4557 { 4558 struct stat64 buf64; 4559 int ret = ::fstat64(fd, &buf64); 4560 int st_mode = buf64.st_mode; 4561 4562 if (ret != -1) { 4563 if ((st_mode & S_IFMT) == S_IFDIR) { 4564 errno = EISDIR; 4565 ::close(fd); 4566 return -1; 4567 } 4568 } else { 4569 ::close(fd); 4570 return -1; 4571 } 4572 } 4573 4574 /* 4575 * All file descriptors that are opened in the JVM and not 4576 * specifically destined for a subprocess should have the 4577 * close-on-exec flag set. If we don't set it, then careless 3rd 4578 * party native code might fork and exec without closing all 4579 * appropriate file descriptors (e.g. as we do in closeDescriptors in 4580 * UNIXProcess.c), and this in turn might: 4581 * 4582 * - cause end-of-file to fail to be detected on some file 4583 * descriptors, resulting in mysterious hangs, or 4584 * 4585 * - might cause an fopen in the subprocess to fail on a system 4586 * suffering from bug 1085341. 4587 * 4588 * (Yes, the default setting of the close-on-exec flag is a Unix 4589 * design flaw) 4590 * 4591 * See: 4592 * 1085341: 32-bit stdio routines should support file descriptors >255 4593 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed 4594 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 4595 */ 4596 #ifdef FD_CLOEXEC 4597 { 4598 int flags = ::fcntl(fd, F_GETFD); 4599 if (flags != -1) 4600 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 4601 } 4602 #endif 4603 4604 if (o_delete != 0) { 4605 ::unlink(path); 4606 } 4607 return fd; 4608 } 4609 4610 4611 // create binary file, rewriting existing file if required 4612 int os::create_binary_file(const char* path, bool rewrite_existing) { 4613 int oflags = O_WRONLY | O_CREAT; 4614 if (!rewrite_existing) { 4615 oflags |= O_EXCL; 4616 } 4617 return ::open64(path, oflags, S_IREAD | S_IWRITE); 4618 } 4619 4620 // return current position of file pointer 4621 jlong os::current_file_offset(int fd) { 4622 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 4623 } 4624 4625 // move file pointer to the specified offset 4626 jlong os::seek_to_file_offset(int fd, jlong offset) { 4627 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 4628 } 4629 4630 // This code originates from JDK's sysAvailable 4631 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 4632 4633 int os::available(int fd, jlong *bytes) { 4634 jlong cur, end; 4635 int mode; 4636 struct stat64 buf64; 4637 4638 if (::fstat64(fd, &buf64) >= 0) { 4639 mode = buf64.st_mode; 4640 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 4641 /* 4642 * XXX: is the following call interruptible? If so, this might 4643 * need to go through the INTERRUPT_IO() wrapper as for other 4644 * blocking, interruptible calls in this file. 4645 */ 4646 int n; 4647 if (::ioctl(fd, FIONREAD, &n) >= 0) { 4648 *bytes = n; 4649 return 1; 4650 } 4651 } 4652 } 4653 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 4654 return 0; 4655 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 4656 return 0; 4657 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 4658 return 0; 4659 } 4660 *bytes = end - cur; 4661 return 1; 4662 } 4663 4664 int os::socket_available(int fd, jint *pbytes) { 4665 // Linux doc says EINTR not returned, unlike Solaris 4666 int ret = ::ioctl(fd, FIONREAD, pbytes); 4667 4668 //%% note ioctl can return 0 when successful, JVM_SocketAvailable 4669 // is expected to return 0 on failure and 1 on success to the jdk. 4670 return (ret < 0) ? 0 : 1; 4671 } 4672 4673 // Map a block of memory. 4674 char* os::map_memory(int fd, const char* file_name, size_t file_offset, 4675 char *addr, size_t bytes, bool read_only, 4676 bool allow_exec) { 4677 int prot; 4678 int flags = MAP_PRIVATE; 4679 4680 if (read_only) { 4681 prot = PROT_READ; 4682 } else { 4683 prot = PROT_READ | PROT_WRITE; 4684 } 4685 4686 if (allow_exec) { 4687 prot |= PROT_EXEC; 4688 } 4689 4690 if (addr != NULL) { 4691 flags |= MAP_FIXED; 4692 } 4693 4694 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 4695 fd, file_offset); 4696 if (mapped_address == MAP_FAILED) { 4697 return NULL; 4698 } 4699 return mapped_address; 4700 } 4701 4702 4703 // Remap a block of memory. 4704 char* os::remap_memory(int fd, const char* file_name, size_t file_offset, 4705 char *addr, size_t bytes, bool read_only, 4706 bool allow_exec) { 4707 // same as map_memory() on this OS 4708 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 4709 allow_exec); 4710 } 4711 4712 4713 // Unmap a block of memory. 4714 bool os::unmap_memory(char* addr, size_t bytes) { 4715 return munmap(addr, bytes) == 0; 4716 } 4717 4718 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 4719 4720 static clockid_t thread_cpu_clockid(Thread* thread) { 4721 pthread_t tid = thread->osthread()->pthread_id(); 4722 clockid_t clockid; 4723 4724 // Get thread clockid 4725 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 4726 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 4727 return clockid; 4728 } 4729 4730 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 4731 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 4732 // of a thread. 4733 // 4734 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 4735 // the fast estimate available on the platform. 4736 4737 jlong os::current_thread_cpu_time() { 4738 if (os::Linux::supports_fast_thread_cpu_time()) { 4739 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4740 } else { 4741 // return user + sys since the cost is the same 4742 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 4743 } 4744 } 4745 4746 jlong os::thread_cpu_time(Thread* thread) { 4747 // consistent with what current_thread_cpu_time() returns 4748 if (os::Linux::supports_fast_thread_cpu_time()) { 4749 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4750 } else { 4751 return slow_thread_cpu_time(thread, true /* user + sys */); 4752 } 4753 } 4754 4755 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 4756 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4757 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4758 } else { 4759 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 4760 } 4761 } 4762 4763 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4764 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4765 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4766 } else { 4767 return slow_thread_cpu_time(thread, user_sys_cpu_time); 4768 } 4769 } 4770 4771 // 4772 // -1 on error. 4773 // 4774 4775 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4776 static bool proc_pid_cpu_avail = true; 4777 static bool proc_task_unchecked = true; 4778 static const char *proc_stat_path = "/proc/%d/stat"; 4779 pid_t tid = thread->osthread()->thread_id(); 4780 int i; 4781 char *s; 4782 char stat[2048]; 4783 int statlen; 4784 char proc_name[64]; 4785 int count; 4786 long sys_time, user_time; 4787 char string[64]; 4788 char cdummy; 4789 int idummy; 4790 long ldummy; 4791 FILE *fp; 4792 4793 // We first try accessing /proc/<pid>/cpu since this is faster to 4794 // process. If this file is not present (linux kernels 2.5 and above) 4795 // then we open /proc/<pid>/stat. 4796 if ( proc_pid_cpu_avail ) { 4797 sprintf(proc_name, "/proc/%d/cpu", tid); 4798 fp = fopen(proc_name, "r"); 4799 if ( fp != NULL ) { 4800 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time); 4801 fclose(fp); 4802 if ( count != 3 ) return -1; 4803 4804 if (user_sys_cpu_time) { 4805 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4806 } else { 4807 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4808 } 4809 } 4810 else proc_pid_cpu_avail = false; 4811 } 4812 4813 // The /proc/<tid>/stat aggregates per-process usage on 4814 // new Linux kernels 2.6+ where NPTL is supported. 4815 // The /proc/self/task/<tid>/stat still has the per-thread usage. 4816 // See bug 6328462. 4817 // There can be no directory /proc/self/task on kernels 2.4 with NPTL 4818 // and possibly in some other cases, so we check its availability. 4819 if (proc_task_unchecked && os::Linux::is_NPTL()) { 4820 // This is executed only once 4821 proc_task_unchecked = false; 4822 fp = fopen("/proc/self/task", "r"); 4823 if (fp != NULL) { 4824 proc_stat_path = "/proc/self/task/%d/stat"; 4825 fclose(fp); 4826 } 4827 } 4828 4829 sprintf(proc_name, proc_stat_path, tid); 4830 fp = fopen(proc_name, "r"); 4831 if ( fp == NULL ) return -1; 4832 statlen = fread(stat, 1, 2047, fp); 4833 stat[statlen] = '\0'; 4834 fclose(fp); 4835 4836 // Skip pid and the command string. Note that we could be dealing with 4837 // weird command names, e.g. user could decide to rename java launcher 4838 // to "java 1.4.2 :)", then the stat file would look like 4839 // 1234 (java 1.4.2 :)) R ... ... 4840 // We don't really need to know the command string, just find the last 4841 // occurrence of ")" and then start parsing from there. See bug 4726580. 4842 s = strrchr(stat, ')'); 4843 i = 0; 4844 if (s == NULL ) return -1; 4845 4846 // Skip blank chars 4847 do s++; while (isspace(*s)); 4848 4849 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 4850 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 4851 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 4852 &user_time, &sys_time); 4853 if ( count != 13 ) return -1; 4854 if (user_sys_cpu_time) { 4855 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4856 } else { 4857 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4858 } 4859 } 4860 4861 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4862 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4863 info_ptr->may_skip_backward = false; // elapsed time not wall time 4864 info_ptr->may_skip_forward = false; // elapsed time not wall time 4865 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4866 } 4867 4868 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4869 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4870 info_ptr->may_skip_backward = false; // elapsed time not wall time 4871 info_ptr->may_skip_forward = false; // elapsed time not wall time 4872 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4873 } 4874 4875 bool os::is_thread_cpu_time_supported() { 4876 return true; 4877 } 4878 4879 // System loadavg support. Returns -1 if load average cannot be obtained. 4880 // Linux doesn't yet have a (official) notion of processor sets, 4881 // so just return the system wide load average. 4882 int os::loadavg(double loadavg[], int nelem) { 4883 return ::getloadavg(loadavg, nelem); 4884 } 4885 4886 void os::pause() { 4887 char filename[MAX_PATH]; 4888 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 4889 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 4890 } else { 4891 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 4892 } 4893 4894 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 4895 if (fd != -1) { 4896 struct stat buf; 4897 ::close(fd); 4898 while (::stat(filename, &buf) == 0) { 4899 (void)::poll(NULL, 0, 100); 4900 } 4901 } else { 4902 jio_fprintf(stderr, 4903 "Could not open pause file '%s', continuing immediately.\n", filename); 4904 } 4905 } 4906 4907 4908 // Refer to the comments in os_solaris.cpp park-unpark. 4909 // 4910 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 4911 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 4912 // For specifics regarding the bug see GLIBC BUGID 261237 : 4913 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 4914 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 4915 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 4916 // is used. (The simple C test-case provided in the GLIBC bug report manifests the 4917 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 4918 // and monitorenter when we're using 1-0 locking. All those operations may result in 4919 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 4920 // of libpthread avoids the problem, but isn't practical. 4921 // 4922 // Possible remedies: 4923 // 4924 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 4925 // This is palliative and probabilistic, however. If the thread is preempted 4926 // between the call to compute_abstime() and pthread_cond_timedwait(), more 4927 // than the minimum period may have passed, and the abstime may be stale (in the 4928 // past) resultin in a hang. Using this technique reduces the odds of a hang 4929 // but the JVM is still vulnerable, particularly on heavily loaded systems. 4930 // 4931 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 4932 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set 4933 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 4934 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant 4935 // thread. 4936 // 4937 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 4938 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 4939 // a timeout request to the chron thread and then blocking via pthread_cond_wait(). 4940 // This also works well. In fact it avoids kernel-level scalability impediments 4941 // on certain platforms that don't handle lots of active pthread_cond_timedwait() 4942 // timers in a graceful fashion. 4943 // 4944 // 4. When the abstime value is in the past it appears that control returns 4945 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 4946 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we 4947 // can avoid the problem by reinitializing the condvar -- by cond_destroy() 4948 // followed by cond_init() -- after all calls to pthread_cond_timedwait(). 4949 // It may be possible to avoid reinitialization by checking the return 4950 // value from pthread_cond_timedwait(). In addition to reinitializing the 4951 // condvar we must establish the invariant that cond_signal() is only called 4952 // within critical sections protected by the adjunct mutex. This prevents 4953 // cond_signal() from "seeing" a condvar that's in the midst of being 4954 // reinitialized or that is corrupt. Sadly, this invariant obviates the 4955 // desirable signal-after-unlock optimization that avoids futile context switching. 4956 // 4957 // I'm also concerned that some versions of NTPL might allocate an auxilliary 4958 // structure when a condvar is used or initialized. cond_destroy() would 4959 // release the helper structure. Our reinitialize-after-timedwait fix 4960 // put excessive stress on malloc/free and locks protecting the c-heap. 4961 // 4962 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 4963 // It may be possible to refine (4) by checking the kernel and NTPL verisons 4964 // and only enabling the work-around for vulnerable environments. 4965 4966 // utility to compute the abstime argument to timedwait: 4967 // millis is the relative timeout time 4968 // abstime will be the absolute timeout time 4969 // TODO: replace compute_abstime() with unpackTime() 4970 4971 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 4972 if (millis < 0) millis = 0; 4973 struct timeval now; 4974 int status = gettimeofday(&now, NULL); 4975 assert(status == 0, "gettimeofday"); 4976 jlong seconds = millis / 1000; 4977 millis %= 1000; 4978 if (seconds > 50000000) { // see man cond_timedwait(3T) 4979 seconds = 50000000; 4980 } 4981 abstime->tv_sec = now.tv_sec + seconds; 4982 long usec = now.tv_usec + millis * 1000; 4983 if (usec >= 1000000) { 4984 abstime->tv_sec += 1; 4985 usec -= 1000000; 4986 } 4987 abstime->tv_nsec = usec * 1000; 4988 return abstime; 4989 } 4990 4991 4992 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately. 4993 // Conceptually TryPark() should be equivalent to park(0). 4994 4995 int os::PlatformEvent::TryPark() { 4996 for (;;) { 4997 const int v = _Event ; 4998 guarantee ((v == 0) || (v == 1), "invariant") ; 4999 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ; 5000 } 5001 } 5002 5003 void os::PlatformEvent::park() { // AKA "down()" 5004 // Invariant: Only the thread associated with the Event/PlatformEvent 5005 // may call park(). 5006 // TODO: assert that _Assoc != NULL or _Assoc == Self 5007 int v ; 5008 for (;;) { 5009 v = _Event ; 5010 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 5011 } 5012 guarantee (v >= 0, "invariant") ; 5013 if (v == 0) { 5014 // Do this the hard way by blocking ... 5015 int status = pthread_mutex_lock(_mutex); 5016 assert_status(status == 0, status, "mutex_lock"); 5017 guarantee (_nParked == 0, "invariant") ; 5018 ++ _nParked ; 5019 while (_Event < 0) { 5020 status = pthread_cond_wait(_cond, _mutex); 5021 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5022 // Treat this the same as if the wait was interrupted 5023 if (status == ETIME) { status = EINTR; } 5024 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5025 } 5026 -- _nParked ; 5027 5028 // In theory we could move the ST of 0 into _Event past the unlock(), 5029 // but then we'd need a MEMBAR after the ST. 5030 _Event = 0 ; 5031 status = pthread_mutex_unlock(_mutex); 5032 assert_status(status == 0, status, "mutex_unlock"); 5033 } 5034 guarantee (_Event >= 0, "invariant") ; 5035 } 5036 5037 int os::PlatformEvent::park(jlong millis) { 5038 guarantee (_nParked == 0, "invariant") ; 5039 5040 int v ; 5041 for (;;) { 5042 v = _Event ; 5043 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 5044 } 5045 guarantee (v >= 0, "invariant") ; 5046 if (v != 0) return OS_OK ; 5047 5048 // We do this the hard way, by blocking the thread. 5049 // Consider enforcing a minimum timeout value. 5050 struct timespec abst; 5051 compute_abstime(&abst, millis); 5052 5053 int ret = OS_TIMEOUT; 5054 int status = pthread_mutex_lock(_mutex); 5055 assert_status(status == 0, status, "mutex_lock"); 5056 guarantee (_nParked == 0, "invariant") ; 5057 ++_nParked ; 5058 5059 // Object.wait(timo) will return because of 5060 // (a) notification 5061 // (b) timeout 5062 // (c) thread.interrupt 5063 // 5064 // Thread.interrupt and object.notify{All} both call Event::set. 5065 // That is, we treat thread.interrupt as a special case of notification. 5066 // The underlying Solaris implementation, cond_timedwait, admits 5067 // spurious/premature wakeups, but the JLS/JVM spec prevents the 5068 // JVM from making those visible to Java code. As such, we must 5069 // filter out spurious wakeups. We assume all ETIME returns are valid. 5070 // 5071 // TODO: properly differentiate simultaneous notify+interrupt. 5072 // In that case, we should propagate the notify to another waiter. 5073 5074 while (_Event < 0) { 5075 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst); 5076 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5077 pthread_cond_destroy (_cond); 5078 pthread_cond_init (_cond, NULL) ; 5079 } 5080 assert_status(status == 0 || status == EINTR || 5081 status == ETIME || status == ETIMEDOUT, 5082 status, "cond_timedwait"); 5083 if (!FilterSpuriousWakeups) break ; // previous semantics 5084 if (status == ETIME || status == ETIMEDOUT) break ; 5085 // We consume and ignore EINTR and spurious wakeups. 5086 } 5087 --_nParked ; 5088 if (_Event >= 0) { 5089 ret = OS_OK; 5090 } 5091 _Event = 0 ; 5092 status = pthread_mutex_unlock(_mutex); 5093 assert_status(status == 0, status, "mutex_unlock"); 5094 assert (_nParked == 0, "invariant") ; 5095 return ret; 5096 } 5097 5098 void os::PlatformEvent::unpark() { 5099 int v, AnyWaiters ; 5100 for (;;) { 5101 v = _Event ; 5102 if (v > 0) { 5103 // The LD of _Event could have reordered or be satisfied 5104 // by a read-aside from this processor's write buffer. 5105 // To avoid problems execute a barrier and then 5106 // ratify the value. 5107 OrderAccess::fence() ; 5108 if (_Event == v) return ; 5109 continue ; 5110 } 5111 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ; 5112 } 5113 if (v < 0) { 5114 // Wait for the thread associated with the event to vacate 5115 int status = pthread_mutex_lock(_mutex); 5116 assert_status(status == 0, status, "mutex_lock"); 5117 AnyWaiters = _nParked ; 5118 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ; 5119 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 5120 AnyWaiters = 0 ; 5121 pthread_cond_signal (_cond); 5122 } 5123 status = pthread_mutex_unlock(_mutex); 5124 assert_status(status == 0, status, "mutex_unlock"); 5125 if (AnyWaiters != 0) { 5126 status = pthread_cond_signal(_cond); 5127 assert_status(status == 0, status, "cond_signal"); 5128 } 5129 } 5130 5131 // Note that we signal() _after dropping the lock for "immortal" Events. 5132 // This is safe and avoids a common class of futile wakeups. In rare 5133 // circumstances this can cause a thread to return prematurely from 5134 // cond_{timed}wait() but the spurious wakeup is benign and the victim will 5135 // simply re-test the condition and re-park itself. 5136 } 5137 5138 5139 // JSR166 5140 // ------------------------------------------------------- 5141 5142 /* 5143 * The solaris and linux implementations of park/unpark are fairly 5144 * conservative for now, but can be improved. They currently use a 5145 * mutex/condvar pair, plus a a count. 5146 * Park decrements count if > 0, else does a condvar wait. Unpark 5147 * sets count to 1 and signals condvar. Only one thread ever waits 5148 * on the condvar. Contention seen when trying to park implies that someone 5149 * is unparking you, so don't wait. And spurious returns are fine, so there 5150 * is no need to track notifications. 5151 */ 5152 5153 #define MAX_SECS 100000000 5154 /* 5155 * This code is common to linux and solaris and will be moved to a 5156 * common place in dolphin. 5157 * 5158 * The passed in time value is either a relative time in nanoseconds 5159 * or an absolute time in milliseconds. Either way it has to be unpacked 5160 * into suitable seconds and nanoseconds components and stored in the 5161 * given timespec structure. 5162 * Given time is a 64-bit value and the time_t used in the timespec is only 5163 * a signed-32-bit value (except on 64-bit Linux) we have to watch for 5164 * overflow if times way in the future are given. Further on Solaris versions 5165 * prior to 10 there is a restriction (see cond_timedwait) that the specified 5166 * number of seconds, in abstime, is less than current_time + 100,000,000. 5167 * As it will be 28 years before "now + 100000000" will overflow we can 5168 * ignore overflow and just impose a hard-limit on seconds using the value 5169 * of "now + 100,000,000". This places a limit on the timeout of about 3.17 5170 * years from "now". 5171 */ 5172 5173 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5174 assert (time > 0, "convertTime"); 5175 5176 struct timeval now; 5177 int status = gettimeofday(&now, NULL); 5178 assert(status == 0, "gettimeofday"); 5179 5180 time_t max_secs = now.tv_sec + MAX_SECS; 5181 5182 if (isAbsolute) { 5183 jlong secs = time / 1000; 5184 if (secs > max_secs) { 5185 absTime->tv_sec = max_secs; 5186 } 5187 else { 5188 absTime->tv_sec = secs; 5189 } 5190 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5191 } 5192 else { 5193 jlong secs = time / NANOSECS_PER_SEC; 5194 if (secs >= MAX_SECS) { 5195 absTime->tv_sec = max_secs; 5196 absTime->tv_nsec = 0; 5197 } 5198 else { 5199 absTime->tv_sec = now.tv_sec + secs; 5200 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5201 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5202 absTime->tv_nsec -= NANOSECS_PER_SEC; 5203 ++absTime->tv_sec; // note: this must be <= max_secs 5204 } 5205 } 5206 } 5207 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5208 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5209 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5210 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5211 } 5212 5213 void Parker::park(bool isAbsolute, jlong time) { 5214 // Optional fast-path check: 5215 // Return immediately if a permit is available. 5216 if (_counter > 0) { 5217 _counter = 0 ; 5218 OrderAccess::fence(); 5219 return ; 5220 } 5221 5222 Thread* thread = Thread::current(); 5223 assert(thread->is_Java_thread(), "Must be JavaThread"); 5224 JavaThread *jt = (JavaThread *)thread; 5225 5226 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5227 // Check interrupt before trying to wait 5228 if (Thread::is_interrupted(thread, false)) { 5229 return; 5230 } 5231 5232 // Next, demultiplex/decode time arguments 5233 timespec absTime; 5234 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all 5235 return; 5236 } 5237 if (time > 0) { 5238 unpackTime(&absTime, isAbsolute, time); 5239 } 5240 5241 5242 // Enter safepoint region 5243 // Beware of deadlocks such as 6317397. 5244 // The per-thread Parker:: mutex is a classic leaf-lock. 5245 // In particular a thread must never block on the Threads_lock while 5246 // holding the Parker:: mutex. If safepoints are pending both the 5247 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5248 ThreadBlockInVM tbivm(jt); 5249 5250 // Don't wait if cannot get lock since interference arises from 5251 // unblocking. Also. check interrupt before trying wait 5252 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5253 return; 5254 } 5255 5256 int status ; 5257 if (_counter > 0) { // no wait needed 5258 _counter = 0; 5259 status = pthread_mutex_unlock(_mutex); 5260 assert (status == 0, "invariant") ; 5261 OrderAccess::fence(); 5262 return; 5263 } 5264 5265 #ifdef ASSERT 5266 // Don't catch signals while blocked; let the running threads have the signals. 5267 // (This allows a debugger to break into the running thread.) 5268 sigset_t oldsigs; 5269 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5270 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5271 #endif 5272 5273 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5274 jt->set_suspend_equivalent(); 5275 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5276 5277 if (time == 0) { 5278 status = pthread_cond_wait (_cond, _mutex) ; 5279 } else { 5280 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ; 5281 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5282 pthread_cond_destroy (_cond) ; 5283 pthread_cond_init (_cond, NULL); 5284 } 5285 } 5286 assert_status(status == 0 || status == EINTR || 5287 status == ETIME || status == ETIMEDOUT, 5288 status, "cond_timedwait"); 5289 5290 #ifdef ASSERT 5291 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5292 #endif 5293 5294 _counter = 0 ; 5295 status = pthread_mutex_unlock(_mutex) ; 5296 assert_status(status == 0, status, "invariant") ; 5297 // If externally suspended while waiting, re-suspend 5298 if (jt->handle_special_suspend_equivalent_condition()) { 5299 jt->java_suspend_self(); 5300 } 5301 5302 OrderAccess::fence(); 5303 } 5304 5305 void Parker::unpark() { 5306 int s, status ; 5307 status = pthread_mutex_lock(_mutex); 5308 assert (status == 0, "invariant") ; 5309 s = _counter; 5310 _counter = 1; 5311 if (s < 1) { 5312 if (WorkAroundNPTLTimedWaitHang) { 5313 status = pthread_cond_signal (_cond) ; 5314 assert (status == 0, "invariant") ; 5315 status = pthread_mutex_unlock(_mutex); 5316 assert (status == 0, "invariant") ; 5317 } else { 5318 status = pthread_mutex_unlock(_mutex); 5319 assert (status == 0, "invariant") ; 5320 status = pthread_cond_signal (_cond) ; 5321 assert (status == 0, "invariant") ; 5322 } 5323 } else { 5324 pthread_mutex_unlock(_mutex); 5325 assert (status == 0, "invariant") ; 5326 } 5327 } 5328 5329 5330 extern char** environ; 5331 5332 #ifndef __NR_fork 5333 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) 5334 #endif 5335 5336 #ifndef __NR_execve 5337 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) 5338 #endif 5339 5340 // Run the specified command in a separate process. Return its exit value, 5341 // or -1 on failure (e.g. can't fork a new process). 5342 // Unlike system(), this function can be called from signal handler. It 5343 // doesn't block SIGINT et al. 5344 int os::fork_and_exec(char* cmd) { 5345 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5346 5347 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run 5348 // pthread_atfork handlers and reset pthread library. All we need is a 5349 // separate process to execve. Make a direct syscall to fork process. 5350 // On IA64 there's no fork syscall, we have to use fork() and hope for 5351 // the best... 5352 pid_t pid = NOT_IA64(syscall(__NR_fork);) 5353 IA64_ONLY(fork();) 5354 5355 if (pid < 0) { 5356 // fork failed 5357 return -1; 5358 5359 } else if (pid == 0) { 5360 // child process 5361 5362 // execve() in LinuxThreads will call pthread_kill_other_threads_np() 5363 // first to kill every thread on the thread list. Because this list is 5364 // not reset by fork() (see notes above), execve() will instead kill 5365 // every thread in the parent process. We know this is the only thread 5366 // in the new process, so make a system call directly. 5367 // IA64 should use normal execve() from glibc to match the glibc fork() 5368 // above. 5369 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);) 5370 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);) 5371 5372 // execve failed 5373 _exit(-1); 5374 5375 } else { 5376 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5377 // care about the actual exit code, for now. 5378 5379 int status; 5380 5381 // Wait for the child process to exit. This returns immediately if 5382 // the child has already exited. */ 5383 while (waitpid(pid, &status, 0) < 0) { 5384 switch (errno) { 5385 case ECHILD: return 0; 5386 case EINTR: break; 5387 default: return -1; 5388 } 5389 } 5390 5391 if (WIFEXITED(status)) { 5392 // The child exited normally; get its exit code. 5393 return WEXITSTATUS(status); 5394 } else if (WIFSIGNALED(status)) { 5395 // The child exited because of a signal 5396 // The best value to return is 0x80 + signal number, 5397 // because that is what all Unix shells do, and because 5398 // it allows callers to distinguish between process exit and 5399 // process death by signal. 5400 return 0x80 + WTERMSIG(status); 5401 } else { 5402 // Unknown exit code; pass it through 5403 return status; 5404 } 5405 } 5406 } 5407 5408 // is_headless_jre() 5409 // 5410 // Test for the existence of xawt/libmawt.so or libawt_xawt.so 5411 // in order to report if we are running in a headless jre 5412 // 5413 // Since JDK8 xawt/libmawt.so was moved into the same directory 5414 // as libawt.so, and renamed libawt_xawt.so 5415 // 5416 bool os::is_headless_jre() { 5417 struct stat statbuf; 5418 char buf[MAXPATHLEN]; 5419 char libmawtpath[MAXPATHLEN]; 5420 const char *xawtstr = "/xawt/libmawt.so"; 5421 const char *new_xawtstr = "/libawt_xawt.so"; 5422 char *p; 5423 5424 // Get path to libjvm.so 5425 os::jvm_path(buf, sizeof(buf)); 5426 5427 // Get rid of libjvm.so 5428 p = strrchr(buf, '/'); 5429 if (p == NULL) return false; 5430 else *p = '\0'; 5431 5432 // Get rid of client or server 5433 p = strrchr(buf, '/'); 5434 if (p == NULL) return false; 5435 else *p = '\0'; 5436 5437 // check xawt/libmawt.so 5438 strcpy(libmawtpath, buf); 5439 strcat(libmawtpath, xawtstr); 5440 if (::stat(libmawtpath, &statbuf) == 0) return false; 5441 5442 // check libawt_xawt.so 5443 strcpy(libmawtpath, buf); 5444 strcat(libmawtpath, new_xawtstr); 5445 if (::stat(libmawtpath, &statbuf) == 0) return false; 5446 5447 return true; 5448 } 5449 5450 // Generate the candidate core paths into the supplied buffer 5451 // Return the number of characters actually generated 5452 int os::get_core_paths(char* buffer, size_t bufferSize) { 5453 static char cwd[O_BUFLEN]; 5454 int n; 5455 5456 get_current_directory(cwd, sizeof(cwd)); 5457 5458 n = jio_snprintf(buffer, bufferSize, "%s/core or core.%d", cwd, current_process_id()); 5459 5460 // Truncate if theoretical string was longer than bufferSize 5461 n = MIN2(n, (int)bufferSize); 5462 5463 return n; 5464 } 5465 5466 #ifdef JAVASE_EMBEDDED 5467 // 5468 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory. 5469 // 5470 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL; 5471 5472 // ctor 5473 // 5474 MemNotifyThread::MemNotifyThread(int fd): Thread() { 5475 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread"); 5476 _fd = fd; 5477 5478 if (os::create_thread(this, os::os_thread)) { 5479 _memnotify_thread = this; 5480 os::set_priority(this, NearMaxPriority); 5481 os::start_thread(this); 5482 } 5483 } 5484 5485 // Where all the work gets done 5486 // 5487 void MemNotifyThread::run() { 5488 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread"); 5489 5490 // Set up the select arguments 5491 fd_set rfds; 5492 if (_fd != -1) { 5493 FD_ZERO(&rfds); 5494 FD_SET(_fd, &rfds); 5495 } 5496 5497 // Now wait for the mem_notify device to wake up 5498 while (1) { 5499 // Wait for the mem_notify device to signal us.. 5500 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL); 5501 if (rc == -1) { 5502 perror("select!\n"); 5503 break; 5504 } else if (rc) { 5505 //ssize_t free_before = os::available_memory(); 5506 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024); 5507 5508 // The kernel is telling us there is not much memory left... 5509 // try to do something about that 5510 5511 // If we are not already in a GC, try one. 5512 if (!Universe::heap()->is_gc_active()) { 5513 Universe::heap()->collect(GCCause::_allocation_failure); 5514 5515 //ssize_t free_after = os::available_memory(); 5516 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024); 5517 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024); 5518 } 5519 // We might want to do something like the following if we find the GC's are not helping... 5520 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true); 5521 } 5522 } 5523 } 5524 5525 // 5526 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it. 5527 // 5528 void MemNotifyThread::start() { 5529 int fd; 5530 fd = open ("/dev/mem_notify", O_RDONLY, 0); 5531 if (fd < 0) { 5532 return; 5533 } 5534 5535 if (memnotify_thread() == NULL) { 5536 new MemNotifyThread(fd); 5537 } 5538 } 5539 #endif // JAVASE_EMBEDDED