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