os_linux.cpp revision 1930:54f5dd2aa1d9
1/* 2 * Copyright (c) 1999, 2010, 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# define __STDC_FORMAT_MACROS 26 27// no precompiled headers 28#include "classfile/classLoader.hpp" 29#include "classfile/systemDictionary.hpp" 30#include "classfile/vmSymbols.hpp" 31#include "code/icBuffer.hpp" 32#include "code/vtableStubs.hpp" 33#include "compiler/compileBroker.hpp" 34#include "interpreter/interpreter.hpp" 35#include "jvm_linux.h" 36#include "memory/allocation.inline.hpp" 37#include "memory/filemap.hpp" 38#include "mutex_linux.inline.hpp" 39#include "oops/oop.inline.hpp" 40#include "os_share_linux.hpp" 41#include "prims/jniFastGetField.hpp" 42#include "prims/jvm.h" 43#include "prims/jvm_misc.hpp" 44#include "runtime/arguments.hpp" 45#include "runtime/extendedPC.hpp" 46#include "runtime/globals.hpp" 47#include "runtime/interfaceSupport.hpp" 48#include "runtime/java.hpp" 49#include "runtime/javaCalls.hpp" 50#include "runtime/mutexLocker.hpp" 51#include "runtime/objectMonitor.hpp" 52#include "runtime/osThread.hpp" 53#include "runtime/perfMemory.hpp" 54#include "runtime/sharedRuntime.hpp" 55#include "runtime/statSampler.hpp" 56#include "runtime/stubRoutines.hpp" 57#include "runtime/threadCritical.hpp" 58#include "runtime/timer.hpp" 59#include "services/attachListener.hpp" 60#include "services/runtimeService.hpp" 61#include "thread_linux.inline.hpp" 62#include "utilities/decoder.hpp" 63#include "utilities/defaultStream.hpp" 64#include "utilities/events.hpp" 65#include "utilities/growableArray.hpp" 66#include "utilities/vmError.hpp" 67#ifdef TARGET_ARCH_x86 68# include "assembler_x86.inline.hpp" 69# include "nativeInst_x86.hpp" 70#endif 71#ifdef TARGET_ARCH_sparc 72# include "assembler_sparc.inline.hpp" 73# include "nativeInst_sparc.hpp" 74#endif 75#ifdef TARGET_ARCH_zero 76# include "assembler_zero.inline.hpp" 77# include "nativeInst_zero.hpp" 78#endif 79#ifdef COMPILER1 80#include "c1/c1_Runtime1.hpp" 81#endif 82#ifdef COMPILER2 83#include "opto/runtime.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> 118 119#define MAX_PATH (2 * K) 120 121// for timer info max values which include all bits 122#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 123#define SEC_IN_NANOSECS 1000000000LL 124 125//////////////////////////////////////////////////////////////////////////////// 126// global variables 127julong os::Linux::_physical_memory = 0; 128 129address os::Linux::_initial_thread_stack_bottom = NULL; 130uintptr_t os::Linux::_initial_thread_stack_size = 0; 131 132int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 133int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 134Mutex* os::Linux::_createThread_lock = NULL; 135pthread_t os::Linux::_main_thread; 136int os::Linux::_page_size = -1; 137bool os::Linux::_is_floating_stack = false; 138bool os::Linux::_is_NPTL = false; 139bool os::Linux::_supports_fast_thread_cpu_time = false; 140const char * os::Linux::_glibc_version = NULL; 141const char * os::Linux::_libpthread_version = NULL; 142 143static jlong initial_time_count=0; 144 145static int clock_tics_per_sec = 100; 146 147// For diagnostics to print a message once. see run_periodic_checks 148static sigset_t check_signal_done; 149static bool check_signals = true;; 150 151static pid_t _initial_pid = 0; 152 153/* Signal number used to suspend/resume a thread */ 154 155/* do not use any signal number less than SIGSEGV, see 4355769 */ 156static int SR_signum = SIGUSR2; 157sigset_t SR_sigset; 158 159/* Used to protect dlsym() calls */ 160static pthread_mutex_t dl_mutex; 161 162//////////////////////////////////////////////////////////////////////////////// 163// utility functions 164 165static int SR_initialize(); 166static int SR_finalize(); 167 168julong os::available_memory() { 169 return Linux::available_memory(); 170} 171 172julong os::Linux::available_memory() { 173 // values in struct sysinfo are "unsigned long" 174 struct sysinfo si; 175 sysinfo(&si); 176 177 return (julong)si.freeram * si.mem_unit; 178} 179 180julong os::physical_memory() { 181 return Linux::physical_memory(); 182} 183 184julong os::allocatable_physical_memory(julong size) { 185#ifdef _LP64 186 return size; 187#else 188 julong result = MIN2(size, (julong)3800*M); 189 if (!is_allocatable(result)) { 190 // See comments under solaris for alignment considerations 191 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size(); 192 result = MIN2(size, reasonable_size); 193 } 194 return result; 195#endif // _LP64 196} 197 198//////////////////////////////////////////////////////////////////////////////// 199// environment support 200 201bool os::getenv(const char* name, char* buf, int len) { 202 const char* val = ::getenv(name); 203 if (val != NULL && strlen(val) < (size_t)len) { 204 strcpy(buf, val); 205 return true; 206 } 207 if (len > 0) buf[0] = 0; // return a null string 208 return false; 209} 210 211 212// Return true if user is running as root. 213 214bool os::have_special_privileges() { 215 static bool init = false; 216 static bool privileges = false; 217 if (!init) { 218 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 219 init = true; 220 } 221 return privileges; 222} 223 224 225#ifndef SYS_gettid 226// i386: 224, ia64: 1105, amd64: 186, sparc 143 227#ifdef __ia64__ 228#define SYS_gettid 1105 229#elif __i386__ 230#define SYS_gettid 224 231#elif __amd64__ 232#define SYS_gettid 186 233#elif __sparc__ 234#define SYS_gettid 143 235#else 236#error define gettid for the arch 237#endif 238#endif 239 240// Cpu architecture string 241#if defined(ZERO) 242static char cpu_arch[] = ZERO_LIBARCH; 243#elif defined(IA64) 244static char cpu_arch[] = "ia64"; 245#elif defined(IA32) 246static char cpu_arch[] = "i386"; 247#elif defined(AMD64) 248static char cpu_arch[] = "amd64"; 249#elif defined(ARM) 250static char cpu_arch[] = "arm"; 251#elif defined(PPC) 252static char cpu_arch[] = "ppc"; 253#elif defined(SPARC) 254# ifdef _LP64 255static char cpu_arch[] = "sparcv9"; 256# else 257static char cpu_arch[] = "sparc"; 258# endif 259#else 260#error Add appropriate cpu_arch setting 261#endif 262 263 264// pid_t gettid() 265// 266// Returns the kernel thread id of the currently running thread. Kernel 267// thread id is used to access /proc. 268// 269// (Note that getpid() on LinuxThreads returns kernel thread id too; but 270// on NPTL, it returns the same pid for all threads, as required by POSIX.) 271// 272pid_t os::Linux::gettid() { 273 int rslt = syscall(SYS_gettid); 274 if (rslt == -1) { 275 // old kernel, no NPTL support 276 return getpid(); 277 } else { 278 return (pid_t)rslt; 279 } 280} 281 282// Most versions of linux have a bug where the number of processors are 283// determined by looking at the /proc file system. In a chroot environment, 284// the system call returns 1. This causes the VM to act as if it is 285// a single processor and elide locking (see is_MP() call). 286static bool unsafe_chroot_detected = false; 287static const char *unstable_chroot_error = "/proc file system not found.\n" 288 "Java may be unstable running multithreaded in a chroot " 289 "environment on Linux when /proc filesystem is not mounted."; 290 291void os::Linux::initialize_system_info() { 292 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 293 if (processor_count() == 1) { 294 pid_t pid = os::Linux::gettid(); 295 char fname[32]; 296 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 297 FILE *fp = fopen(fname, "r"); 298 if (fp == NULL) { 299 unsafe_chroot_detected = true; 300 } else { 301 fclose(fp); 302 } 303 } 304 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 305 assert(processor_count() > 0, "linux error"); 306} 307 308void os::init_system_properties_values() { 309// char arch[12]; 310// sysinfo(SI_ARCHITECTURE, arch, sizeof(arch)); 311 312 // The next steps are taken in the product version: 313 // 314 // Obtain the JAVA_HOME value from the location of libjvm[_g].so. 315 // This library should be located at: 316 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so. 317 // 318 // If "/jre/lib/" appears at the right place in the path, then we 319 // assume libjvm[_g].so is installed in a JDK and we use this path. 320 // 321 // Otherwise exit with message: "Could not create the Java virtual machine." 322 // 323 // The following extra steps are taken in the debugging version: 324 // 325 // If "/jre/lib/" does NOT appear at the right place in the path 326 // instead of exit check for $JAVA_HOME environment variable. 327 // 328 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 329 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so 330 // it looks like libjvm[_g].so is installed there 331 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so. 332 // 333 // Otherwise exit. 334 // 335 // Important note: if the location of libjvm.so changes this 336 // code needs to be changed accordingly. 337 338 // The next few definitions allow the code to be verbatim: 339#define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n)) 340#define getenv(n) ::getenv(n) 341 342/* 343 * See ld(1): 344 * The linker uses the following search paths to locate required 345 * shared libraries: 346 * 1: ... 347 * ... 348 * 7: The default directories, normally /lib and /usr/lib. 349 */ 350#if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 351#define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 352#else 353#define DEFAULT_LIBPATH "/lib:/usr/lib" 354#endif 355 356#define EXTENSIONS_DIR "/lib/ext" 357#define ENDORSED_DIR "/lib/endorsed" 358#define REG_DIR "/usr/java/packages" 359 360 { 361 /* sysclasspath, java_home, dll_dir */ 362 { 363 char *home_path; 364 char *dll_path; 365 char *pslash; 366 char buf[MAXPATHLEN]; 367 os::jvm_path(buf, sizeof(buf)); 368 369 // Found the full path to libjvm.so. 370 // Now cut the path to <java_home>/jre if we can. 371 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */ 372 pslash = strrchr(buf, '/'); 373 if (pslash != NULL) 374 *pslash = '\0'; /* get rid of /{client|server|hotspot} */ 375 dll_path = malloc(strlen(buf) + 1); 376 if (dll_path == NULL) 377 return; 378 strcpy(dll_path, buf); 379 Arguments::set_dll_dir(dll_path); 380 381 if (pslash != NULL) { 382 pslash = strrchr(buf, '/'); 383 if (pslash != NULL) { 384 *pslash = '\0'; /* get rid of /<arch> */ 385 pslash = strrchr(buf, '/'); 386 if (pslash != NULL) 387 *pslash = '\0'; /* get rid of /lib */ 388 } 389 } 390 391 home_path = malloc(strlen(buf) + 1); 392 if (home_path == NULL) 393 return; 394 strcpy(home_path, buf); 395 Arguments::set_java_home(home_path); 396 397 if (!set_boot_path('/', ':')) 398 return; 399 } 400 401 /* 402 * Where to look for native libraries 403 * 404 * Note: Due to a legacy implementation, most of the library path 405 * is set in the launcher. This was to accomodate linking restrictions 406 * on legacy Linux implementations (which are no longer supported). 407 * Eventually, all the library path setting will be done here. 408 * 409 * However, to prevent the proliferation of improperly built native 410 * libraries, the new path component /usr/java/packages is added here. 411 * Eventually, all the library path setting will be done here. 412 */ 413 { 414 char *ld_library_path; 415 416 /* 417 * Construct the invariant part of ld_library_path. Note that the 418 * space for the colon and the trailing null are provided by the 419 * nulls included by the sizeof operator (so actually we allocate 420 * a byte more than necessary). 421 */ 422 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") + 423 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH)); 424 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch); 425 426 /* 427 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It 428 * should always exist (until the legacy problem cited above is 429 * addressed). 430 */ 431 char *v = getenv("LD_LIBRARY_PATH"); 432 if (v != NULL) { 433 char *t = ld_library_path; 434 /* That's +1 for the colon and +1 for the trailing '\0' */ 435 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1); 436 sprintf(ld_library_path, "%s:%s", v, t); 437 } 438 Arguments::set_library_path(ld_library_path); 439 } 440 441 /* 442 * Extensions directories. 443 * 444 * Note that the space for the colon and the trailing null are provided 445 * by the nulls included by the sizeof operator (so actually one byte more 446 * than necessary is allocated). 447 */ 448 { 449 char *buf = malloc(strlen(Arguments::get_java_home()) + 450 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR)); 451 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR, 452 Arguments::get_java_home()); 453 Arguments::set_ext_dirs(buf); 454 } 455 456 /* Endorsed standards default directory. */ 457 { 458 char * buf; 459 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR)); 460 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home()); 461 Arguments::set_endorsed_dirs(buf); 462 } 463 } 464 465#undef malloc 466#undef getenv 467#undef EXTENSIONS_DIR 468#undef ENDORSED_DIR 469 470 // Done 471 return; 472} 473 474//////////////////////////////////////////////////////////////////////////////// 475// breakpoint support 476 477void os::breakpoint() { 478 BREAKPOINT; 479} 480 481extern "C" void breakpoint() { 482 // use debugger to set breakpoint here 483} 484 485//////////////////////////////////////////////////////////////////////////////// 486// signal support 487 488debug_only(static bool signal_sets_initialized = false); 489static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 490 491bool os::Linux::is_sig_ignored(int sig) { 492 struct sigaction oact; 493 sigaction(sig, (struct sigaction*)NULL, &oact); 494 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 495 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 496 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) 497 return true; 498 else 499 return false; 500} 501 502void os::Linux::signal_sets_init() { 503 // Should also have an assertion stating we are still single-threaded. 504 assert(!signal_sets_initialized, "Already initialized"); 505 // Fill in signals that are necessarily unblocked for all threads in 506 // the VM. Currently, we unblock the following signals: 507 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 508 // by -Xrs (=ReduceSignalUsage)); 509 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 510 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 511 // the dispositions or masks wrt these signals. 512 // Programs embedding the VM that want to use the above signals for their 513 // own purposes must, at this time, use the "-Xrs" option to prevent 514 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 515 // (See bug 4345157, and other related bugs). 516 // In reality, though, unblocking these signals is really a nop, since 517 // these signals are not blocked by default. 518 sigemptyset(&unblocked_sigs); 519 sigemptyset(&allowdebug_blocked_sigs); 520 sigaddset(&unblocked_sigs, SIGILL); 521 sigaddset(&unblocked_sigs, SIGSEGV); 522 sigaddset(&unblocked_sigs, SIGBUS); 523 sigaddset(&unblocked_sigs, SIGFPE); 524 sigaddset(&unblocked_sigs, SR_signum); 525 526 if (!ReduceSignalUsage) { 527 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 528 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 529 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 530 } 531 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 532 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 533 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 534 } 535 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 536 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 537 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 538 } 539 } 540 // Fill in signals that are blocked by all but the VM thread. 541 sigemptyset(&vm_sigs); 542 if (!ReduceSignalUsage) 543 sigaddset(&vm_sigs, BREAK_SIGNAL); 544 debug_only(signal_sets_initialized = true); 545 546} 547 548// These are signals that are unblocked while a thread is running Java. 549// (For some reason, they get blocked by default.) 550sigset_t* os::Linux::unblocked_signals() { 551 assert(signal_sets_initialized, "Not initialized"); 552 return &unblocked_sigs; 553} 554 555// These are the signals that are blocked while a (non-VM) thread is 556// running Java. Only the VM thread handles these signals. 557sigset_t* os::Linux::vm_signals() { 558 assert(signal_sets_initialized, "Not initialized"); 559 return &vm_sigs; 560} 561 562// These are signals that are blocked during cond_wait to allow debugger in 563sigset_t* os::Linux::allowdebug_blocked_signals() { 564 assert(signal_sets_initialized, "Not initialized"); 565 return &allowdebug_blocked_sigs; 566} 567 568void os::Linux::hotspot_sigmask(Thread* thread) { 569 570 //Save caller's signal mask before setting VM signal mask 571 sigset_t caller_sigmask; 572 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 573 574 OSThread* osthread = thread->osthread(); 575 osthread->set_caller_sigmask(caller_sigmask); 576 577 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 578 579 if (!ReduceSignalUsage) { 580 if (thread->is_VM_thread()) { 581 // Only the VM thread handles BREAK_SIGNAL ... 582 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 583 } else { 584 // ... all other threads block BREAK_SIGNAL 585 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 586 } 587 } 588} 589 590////////////////////////////////////////////////////////////////////////////// 591// detecting pthread library 592 593void os::Linux::libpthread_init() { 594 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION 595 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a 596 // generic name for earlier versions. 597 // Define macros here so we can build HotSpot on old systems. 598# ifndef _CS_GNU_LIBC_VERSION 599# define _CS_GNU_LIBC_VERSION 2 600# endif 601# ifndef _CS_GNU_LIBPTHREAD_VERSION 602# define _CS_GNU_LIBPTHREAD_VERSION 3 603# endif 604 605 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 606 if (n > 0) { 607 char *str = (char *)malloc(n); 608 confstr(_CS_GNU_LIBC_VERSION, str, n); 609 os::Linux::set_glibc_version(str); 610 } else { 611 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version() 612 static char _gnu_libc_version[32]; 613 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version), 614 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release()); 615 os::Linux::set_glibc_version(_gnu_libc_version); 616 } 617 618 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 619 if (n > 0) { 620 char *str = (char *)malloc(n); 621 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 622 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells 623 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this 624 // is the case. LinuxThreads has a hard limit on max number of threads. 625 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value. 626 // On the other hand, NPTL does not have such a limit, sysconf() 627 // will return -1 and errno is not changed. Check if it is really NPTL. 628 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 && 629 strstr(str, "NPTL") && 630 sysconf(_SC_THREAD_THREADS_MAX) > 0) { 631 free(str); 632 os::Linux::set_libpthread_version("linuxthreads"); 633 } else { 634 os::Linux::set_libpthread_version(str); 635 } 636 } else { 637 // glibc before 2.3.2 only has LinuxThreads. 638 os::Linux::set_libpthread_version("linuxthreads"); 639 } 640 641 if (strstr(libpthread_version(), "NPTL")) { 642 os::Linux::set_is_NPTL(); 643 } else { 644 os::Linux::set_is_LinuxThreads(); 645 } 646 647 // LinuxThreads have two flavors: floating-stack mode, which allows variable 648 // stack size; and fixed-stack mode. NPTL is always floating-stack. 649 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) { 650 os::Linux::set_is_floating_stack(); 651 } 652} 653 654///////////////////////////////////////////////////////////////////////////// 655// thread stack 656 657// Force Linux kernel to expand current thread stack. If "bottom" is close 658// to the stack guard, caller should block all signals. 659// 660// MAP_GROWSDOWN: 661// A special mmap() flag that is used to implement thread stacks. It tells 662// kernel that the memory region should extend downwards when needed. This 663// allows early versions of LinuxThreads to only mmap the first few pages 664// when creating a new thread. Linux kernel will automatically expand thread 665// stack as needed (on page faults). 666// 667// However, because the memory region of a MAP_GROWSDOWN stack can grow on 668// demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 669// region, it's hard to tell if the fault is due to a legitimate stack 670// access or because of reading/writing non-exist memory (e.g. buffer 671// overrun). As a rule, if the fault happens below current stack pointer, 672// Linux kernel does not expand stack, instead a SIGSEGV is sent to the 673// application (see Linux kernel fault.c). 674// 675// This Linux feature can cause SIGSEGV when VM bangs thread stack for 676// stack overflow detection. 677// 678// Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 679// not use this flag. However, the stack of initial thread is not created 680// by pthread, it is still MAP_GROWSDOWN. Also it's possible (though 681// unlikely) that user code can create a thread with MAP_GROWSDOWN stack 682// and then attach the thread to JVM. 683// 684// To get around the problem and allow stack banging on Linux, we need to 685// manually expand thread stack after receiving the SIGSEGV. 686// 687// There are two ways to expand thread stack to address "bottom", we used 688// both of them in JVM before 1.5: 689// 1. adjust stack pointer first so that it is below "bottom", and then 690// touch "bottom" 691// 2. mmap() the page in question 692// 693// Now alternate signal stack is gone, it's harder to use 2. For instance, 694// if current sp is already near the lower end of page 101, and we need to 695// call mmap() to map page 100, it is possible that part of the mmap() frame 696// will be placed in page 100. When page 100 is mapped, it is zero-filled. 697// That will destroy the mmap() frame and cause VM to crash. 698// 699// The following code works by adjusting sp first, then accessing the "bottom" 700// page to force a page fault. Linux kernel will then automatically expand the 701// stack mapping. 702// 703// _expand_stack_to() assumes its frame size is less than page size, which 704// should always be true if the function is not inlined. 705 706#if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 707#define NOINLINE 708#else 709#define NOINLINE __attribute__ ((noinline)) 710#endif 711 712static void _expand_stack_to(address bottom) NOINLINE; 713 714static void _expand_stack_to(address bottom) { 715 address sp; 716 size_t size; 717 volatile char *p; 718 719 // Adjust bottom to point to the largest address within the same page, it 720 // gives us a one-page buffer if alloca() allocates slightly more memory. 721 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 722 bottom += os::Linux::page_size() - 1; 723 724 // sp might be slightly above current stack pointer; if that's the case, we 725 // will alloca() a little more space than necessary, which is OK. Don't use 726 // os::current_stack_pointer(), as its result can be slightly below current 727 // stack pointer, causing us to not alloca enough to reach "bottom". 728 sp = (address)&sp; 729 730 if (sp > bottom) { 731 size = sp - bottom; 732 p = (volatile char *)alloca(size); 733 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 734 p[0] = '\0'; 735 } 736} 737 738bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 739 assert(t!=NULL, "just checking"); 740 assert(t->osthread()->expanding_stack(), "expand should be set"); 741 assert(t->stack_base() != NULL, "stack_base was not initialized"); 742 743 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 744 sigset_t mask_all, old_sigset; 745 sigfillset(&mask_all); 746 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 747 _expand_stack_to(addr); 748 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 749 return true; 750 } 751 return false; 752} 753 754////////////////////////////////////////////////////////////////////////////// 755// create new thread 756 757static address highest_vm_reserved_address(); 758 759// check if it's safe to start a new thread 760static bool _thread_safety_check(Thread* thread) { 761 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) { 762 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat) 763 // Heap is mmap'ed at lower end of memory space. Thread stacks are 764 // allocated (MAP_FIXED) from high address space. Every thread stack 765 // occupies a fixed size slot (usually 2Mbytes, but user can change 766 // it to other values if they rebuild LinuxThreads). 767 // 768 // Problem with MAP_FIXED is that mmap() can still succeed even part of 769 // the memory region has already been mmap'ed. That means if we have too 770 // many threads and/or very large heap, eventually thread stack will 771 // collide with heap. 772 // 773 // Here we try to prevent heap/stack collision by comparing current 774 // stack bottom with the highest address that has been mmap'ed by JVM 775 // plus a safety margin for memory maps created by native code. 776 // 777 // This feature can be disabled by setting ThreadSafetyMargin to 0 778 // 779 if (ThreadSafetyMargin > 0) { 780 address stack_bottom = os::current_stack_base() - os::current_stack_size(); 781 782 // not safe if our stack extends below the safety margin 783 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address(); 784 } else { 785 return true; 786 } 787 } else { 788 // Floating stack LinuxThreads or NPTL: 789 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When 790 // there's not enough space left, pthread_create() will fail. If we come 791 // here, that means enough space has been reserved for stack. 792 return true; 793 } 794} 795 796// Thread start routine for all newly created threads 797static void *java_start(Thread *thread) { 798 // Try to randomize the cache line index of hot stack frames. 799 // This helps when threads of the same stack traces evict each other's 800 // cache lines. The threads can be either from the same JVM instance, or 801 // from different JVM instances. The benefit is especially true for 802 // processors with hyperthreading technology. 803 static int counter = 0; 804 int pid = os::current_process_id(); 805 alloca(((pid ^ counter++) & 7) * 128); 806 807 ThreadLocalStorage::set_thread(thread); 808 809 OSThread* osthread = thread->osthread(); 810 Monitor* sync = osthread->startThread_lock(); 811 812 // non floating stack LinuxThreads needs extra check, see above 813 if (!_thread_safety_check(thread)) { 814 // notify parent thread 815 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 816 osthread->set_state(ZOMBIE); 817 sync->notify_all(); 818 return NULL; 819 } 820 821 // thread_id is kernel thread id (similar to Solaris LWP id) 822 osthread->set_thread_id(os::Linux::gettid()); 823 824 if (UseNUMA) { 825 int lgrp_id = os::numa_get_group_id(); 826 if (lgrp_id != -1) { 827 thread->set_lgrp_id(lgrp_id); 828 } 829 } 830 // initialize signal mask for this thread 831 os::Linux::hotspot_sigmask(thread); 832 833 // initialize floating point control register 834 os::Linux::init_thread_fpu_state(); 835 836 // handshaking with parent thread 837 { 838 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 839 840 // notify parent thread 841 osthread->set_state(INITIALIZED); 842 sync->notify_all(); 843 844 // wait until os::start_thread() 845 while (osthread->get_state() == INITIALIZED) { 846 sync->wait(Mutex::_no_safepoint_check_flag); 847 } 848 } 849 850 // call one more level start routine 851 thread->run(); 852 853 return 0; 854} 855 856bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) { 857 assert(thread->osthread() == NULL, "caller responsible"); 858 859 // Allocate the OSThread object 860 OSThread* osthread = new OSThread(NULL, NULL); 861 if (osthread == NULL) { 862 return false; 863 } 864 865 // set the correct thread state 866 osthread->set_thread_type(thr_type); 867 868 // Initial state is ALLOCATED but not INITIALIZED 869 osthread->set_state(ALLOCATED); 870 871 thread->set_osthread(osthread); 872 873 // init thread attributes 874 pthread_attr_t attr; 875 pthread_attr_init(&attr); 876 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 877 878 // stack size 879 if (os::Linux::supports_variable_stack_size()) { 880 // calculate stack size if it's not specified by caller 881 if (stack_size == 0) { 882 stack_size = os::Linux::default_stack_size(thr_type); 883 884 switch (thr_type) { 885 case os::java_thread: 886 // Java threads use ThreadStackSize which default value can be 887 // changed with the flag -Xss 888 assert (JavaThread::stack_size_at_create() > 0, "this should be set"); 889 stack_size = JavaThread::stack_size_at_create(); 890 break; 891 case os::compiler_thread: 892 if (CompilerThreadStackSize > 0) { 893 stack_size = (size_t)(CompilerThreadStackSize * K); 894 break; 895 } // else fall through: 896 // use VMThreadStackSize if CompilerThreadStackSize is not defined 897 case os::vm_thread: 898 case os::pgc_thread: 899 case os::cgc_thread: 900 case os::watcher_thread: 901 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 902 break; 903 } 904 } 905 906 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 907 pthread_attr_setstacksize(&attr, stack_size); 908 } else { 909 // let pthread_create() pick the default value. 910 } 911 912 // glibc guard page 913 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 914 915 ThreadState state; 916 917 { 918 // Serialize thread creation if we are running with fixed stack LinuxThreads 919 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack(); 920 if (lock) { 921 os::Linux::createThread_lock()->lock_without_safepoint_check(); 922 } 923 924 pthread_t tid; 925 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 926 927 pthread_attr_destroy(&attr); 928 929 if (ret != 0) { 930 if (PrintMiscellaneous && (Verbose || WizardMode)) { 931 perror("pthread_create()"); 932 } 933 // Need to clean up stuff we've allocated so far 934 thread->set_osthread(NULL); 935 delete osthread; 936 if (lock) os::Linux::createThread_lock()->unlock(); 937 return false; 938 } 939 940 // Store pthread info into the OSThread 941 osthread->set_pthread_id(tid); 942 943 // Wait until child thread is either initialized or aborted 944 { 945 Monitor* sync_with_child = osthread->startThread_lock(); 946 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 947 while ((state = osthread->get_state()) == ALLOCATED) { 948 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 949 } 950 } 951 952 if (lock) { 953 os::Linux::createThread_lock()->unlock(); 954 } 955 } 956 957 // Aborted due to thread limit being reached 958 if (state == ZOMBIE) { 959 thread->set_osthread(NULL); 960 delete osthread; 961 return false; 962 } 963 964 // The thread is returned suspended (in state INITIALIZED), 965 // and is started higher up in the call chain 966 assert(state == INITIALIZED, "race condition"); 967 return true; 968} 969 970///////////////////////////////////////////////////////////////////////////// 971// attach existing thread 972 973// bootstrap the main thread 974bool os::create_main_thread(JavaThread* thread) { 975 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 976 return create_attached_thread(thread); 977} 978 979bool os::create_attached_thread(JavaThread* thread) { 980#ifdef ASSERT 981 thread->verify_not_published(); 982#endif 983 984 // Allocate the OSThread object 985 OSThread* osthread = new OSThread(NULL, NULL); 986 987 if (osthread == NULL) { 988 return false; 989 } 990 991 // Store pthread info into the OSThread 992 osthread->set_thread_id(os::Linux::gettid()); 993 osthread->set_pthread_id(::pthread_self()); 994 995 // initialize floating point control register 996 os::Linux::init_thread_fpu_state(); 997 998 // Initial thread state is RUNNABLE 999 osthread->set_state(RUNNABLE); 1000 1001 thread->set_osthread(osthread); 1002 1003 if (UseNUMA) { 1004 int lgrp_id = os::numa_get_group_id(); 1005 if (lgrp_id != -1) { 1006 thread->set_lgrp_id(lgrp_id); 1007 } 1008 } 1009 1010 if (os::Linux::is_initial_thread()) { 1011 // If current thread is initial thread, its stack is mapped on demand, 1012 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 1013 // the entire stack region to avoid SEGV in stack banging. 1014 // It is also useful to get around the heap-stack-gap problem on SuSE 1015 // kernel (see 4821821 for details). We first expand stack to the top 1016 // of yellow zone, then enable stack yellow zone (order is significant, 1017 // enabling yellow zone first will crash JVM on SuSE Linux), so there 1018 // is no gap between the last two virtual memory regions. 1019 1020 JavaThread *jt = (JavaThread *)thread; 1021 address addr = jt->stack_yellow_zone_base(); 1022 assert(addr != NULL, "initialization problem?"); 1023 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 1024 1025 osthread->set_expanding_stack(); 1026 os::Linux::manually_expand_stack(jt, addr); 1027 osthread->clear_expanding_stack(); 1028 } 1029 1030 // initialize signal mask for this thread 1031 // and save the caller's signal mask 1032 os::Linux::hotspot_sigmask(thread); 1033 1034 return true; 1035} 1036 1037void os::pd_start_thread(Thread* thread) { 1038 OSThread * osthread = thread->osthread(); 1039 assert(osthread->get_state() != INITIALIZED, "just checking"); 1040 Monitor* sync_with_child = osthread->startThread_lock(); 1041 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 1042 sync_with_child->notify(); 1043} 1044 1045// Free Linux resources related to the OSThread 1046void os::free_thread(OSThread* osthread) { 1047 assert(osthread != NULL, "osthread not set"); 1048 1049 if (Thread::current()->osthread() == osthread) { 1050 // Restore caller's signal mask 1051 sigset_t sigmask = osthread->caller_sigmask(); 1052 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1053 } 1054 1055 delete osthread; 1056} 1057 1058////////////////////////////////////////////////////////////////////////////// 1059// thread local storage 1060 1061int os::allocate_thread_local_storage() { 1062 pthread_key_t key; 1063 int rslt = pthread_key_create(&key, NULL); 1064 assert(rslt == 0, "cannot allocate thread local storage"); 1065 return (int)key; 1066} 1067 1068// Note: This is currently not used by VM, as we don't destroy TLS key 1069// on VM exit. 1070void os::free_thread_local_storage(int index) { 1071 int rslt = pthread_key_delete((pthread_key_t)index); 1072 assert(rslt == 0, "invalid index"); 1073} 1074 1075void os::thread_local_storage_at_put(int index, void* value) { 1076 int rslt = pthread_setspecific((pthread_key_t)index, value); 1077 assert(rslt == 0, "pthread_setspecific failed"); 1078} 1079 1080extern "C" Thread* get_thread() { 1081 return ThreadLocalStorage::thread(); 1082} 1083 1084////////////////////////////////////////////////////////////////////////////// 1085// initial thread 1086 1087// Check if current thread is the initial thread, similar to Solaris thr_main. 1088bool os::Linux::is_initial_thread(void) { 1089 char dummy; 1090 // If called before init complete, thread stack bottom will be null. 1091 // Can be called if fatal error occurs before initialization. 1092 if (initial_thread_stack_bottom() == NULL) return false; 1093 assert(initial_thread_stack_bottom() != NULL && 1094 initial_thread_stack_size() != 0, 1095 "os::init did not locate initial thread's stack region"); 1096 if ((address)&dummy >= initial_thread_stack_bottom() && 1097 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) 1098 return true; 1099 else return false; 1100} 1101 1102// Find the virtual memory area that contains addr 1103static bool find_vma(address addr, address* vma_low, address* vma_high) { 1104 FILE *fp = fopen("/proc/self/maps", "r"); 1105 if (fp) { 1106 address low, high; 1107 while (!feof(fp)) { 1108 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1109 if (low <= addr && addr < high) { 1110 if (vma_low) *vma_low = low; 1111 if (vma_high) *vma_high = high; 1112 fclose (fp); 1113 return true; 1114 } 1115 } 1116 for (;;) { 1117 int ch = fgetc(fp); 1118 if (ch == EOF || ch == (int)'\n') break; 1119 } 1120 } 1121 fclose(fp); 1122 } 1123 return false; 1124} 1125 1126// Locate initial thread stack. This special handling of initial thread stack 1127// is needed because pthread_getattr_np() on most (all?) Linux distros returns 1128// bogus value for initial thread. 1129void os::Linux::capture_initial_stack(size_t max_size) { 1130 // stack size is the easy part, get it from RLIMIT_STACK 1131 size_t stack_size; 1132 struct rlimit rlim; 1133 getrlimit(RLIMIT_STACK, &rlim); 1134 stack_size = rlim.rlim_cur; 1135 1136 // 6308388: a bug in ld.so will relocate its own .data section to the 1137 // lower end of primordial stack; reduce ulimit -s value a little bit 1138 // so we won't install guard page on ld.so's data section. 1139 stack_size -= 2 * page_size(); 1140 1141 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 1142 // 7.1, in both cases we will get 2G in return value. 1143 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 1144 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 1145 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 1146 // in case other parts in glibc still assumes 2M max stack size. 1147 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 1148#ifndef IA64 1149 if (stack_size > 2 * K * K) stack_size = 2 * K * K; 1150#else 1151 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 1152 if (stack_size > 4 * K * K) stack_size = 4 * K * K; 1153#endif 1154 1155 // Try to figure out where the stack base (top) is. This is harder. 1156 // 1157 // When an application is started, glibc saves the initial stack pointer in 1158 // a global variable "__libc_stack_end", which is then used by system 1159 // libraries. __libc_stack_end should be pretty close to stack top. The 1160 // variable is available since the very early days. However, because it is 1161 // a private interface, it could disappear in the future. 1162 // 1163 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1164 // to __libc_stack_end, it is very close to stack top, but isn't the real 1165 // stack top. Note that /proc may not exist if VM is running as a chroot 1166 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1167 // /proc/<pid>/stat could change in the future (though unlikely). 1168 // 1169 // We try __libc_stack_end first. If that doesn't work, look for 1170 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1171 // as a hint, which should work well in most cases. 1172 1173 uintptr_t stack_start; 1174 1175 // try __libc_stack_end first 1176 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1177 if (p && *p) { 1178 stack_start = *p; 1179 } else { 1180 // see if we can get the start_stack field from /proc/self/stat 1181 FILE *fp; 1182 int pid; 1183 char state; 1184 int ppid; 1185 int pgrp; 1186 int session; 1187 int nr; 1188 int tpgrp; 1189 unsigned long flags; 1190 unsigned long minflt; 1191 unsigned long cminflt; 1192 unsigned long majflt; 1193 unsigned long cmajflt; 1194 unsigned long utime; 1195 unsigned long stime; 1196 long cutime; 1197 long cstime; 1198 long prio; 1199 long nice; 1200 long junk; 1201 long it_real; 1202 uintptr_t start; 1203 uintptr_t vsize; 1204 intptr_t rss; 1205 uintptr_t rsslim; 1206 uintptr_t scodes; 1207 uintptr_t ecode; 1208 int i; 1209 1210 // Figure what the primordial thread stack base is. Code is inspired 1211 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1212 // followed by command name surrounded by parentheses, state, etc. 1213 char stat[2048]; 1214 int statlen; 1215 1216 fp = fopen("/proc/self/stat", "r"); 1217 if (fp) { 1218 statlen = fread(stat, 1, 2047, fp); 1219 stat[statlen] = '\0'; 1220 fclose(fp); 1221 1222 // Skip pid and the command string. Note that we could be dealing with 1223 // weird command names, e.g. user could decide to rename java launcher 1224 // to "java 1.4.2 :)", then the stat file would look like 1225 // 1234 (java 1.4.2 :)) R ... ... 1226 // We don't really need to know the command string, just find the last 1227 // occurrence of ")" and then start parsing from there. See bug 4726580. 1228 char * s = strrchr(stat, ')'); 1229 1230 i = 0; 1231 if (s) { 1232 // Skip blank chars 1233 do s++; while (isspace(*s)); 1234 1235#define _UFM UINTX_FORMAT 1236#define _DFM INTX_FORMAT 1237 1238 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */ 1239 /* 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 */ 1240 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, 1241 &state, /* 3 %c */ 1242 &ppid, /* 4 %d */ 1243 &pgrp, /* 5 %d */ 1244 &session, /* 6 %d */ 1245 &nr, /* 7 %d */ 1246 &tpgrp, /* 8 %d */ 1247 &flags, /* 9 %lu */ 1248 &minflt, /* 10 %lu */ 1249 &cminflt, /* 11 %lu */ 1250 &majflt, /* 12 %lu */ 1251 &cmajflt, /* 13 %lu */ 1252 &utime, /* 14 %lu */ 1253 &stime, /* 15 %lu */ 1254 &cutime, /* 16 %ld */ 1255 &cstime, /* 17 %ld */ 1256 &prio, /* 18 %ld */ 1257 &nice, /* 19 %ld */ 1258 &junk, /* 20 %ld */ 1259 &it_real, /* 21 %ld */ 1260 &start, /* 22 UINTX_FORMAT */ 1261 &vsize, /* 23 UINTX_FORMAT */ 1262 &rss, /* 24 INTX_FORMAT */ 1263 &rsslim, /* 25 UINTX_FORMAT */ 1264 &scodes, /* 26 UINTX_FORMAT */ 1265 &ecode, /* 27 UINTX_FORMAT */ 1266 &stack_start); /* 28 UINTX_FORMAT */ 1267 } 1268 1269#undef _UFM 1270#undef _DFM 1271 1272 if (i != 28 - 2) { 1273 assert(false, "Bad conversion from /proc/self/stat"); 1274 // product mode - assume we are the initial thread, good luck in the 1275 // embedded case. 1276 warning("Can't detect initial thread stack location - bad conversion"); 1277 stack_start = (uintptr_t) &rlim; 1278 } 1279 } else { 1280 // For some reason we can't open /proc/self/stat (for example, running on 1281 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1282 // most cases, so don't abort: 1283 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1284 stack_start = (uintptr_t) &rlim; 1285 } 1286 } 1287 1288 // Now we have a pointer (stack_start) very close to the stack top, the 1289 // next thing to do is to figure out the exact location of stack top. We 1290 // can find out the virtual memory area that contains stack_start by 1291 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1292 // and its upper limit is the real stack top. (again, this would fail if 1293 // running inside chroot, because /proc may not exist.) 1294 1295 uintptr_t stack_top; 1296 address low, high; 1297 if (find_vma((address)stack_start, &low, &high)) { 1298 // success, "high" is the true stack top. (ignore "low", because initial 1299 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1300 stack_top = (uintptr_t)high; 1301 } else { 1302 // failed, likely because /proc/self/maps does not exist 1303 warning("Can't detect initial thread stack location - find_vma failed"); 1304 // best effort: stack_start is normally within a few pages below the real 1305 // stack top, use it as stack top, and reduce stack size so we won't put 1306 // guard page outside stack. 1307 stack_top = stack_start; 1308 stack_size -= 16 * page_size(); 1309 } 1310 1311 // stack_top could be partially down the page so align it 1312 stack_top = align_size_up(stack_top, page_size()); 1313 1314 if (max_size && stack_size > max_size) { 1315 _initial_thread_stack_size = max_size; 1316 } else { 1317 _initial_thread_stack_size = stack_size; 1318 } 1319 1320 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1321 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1322} 1323 1324//////////////////////////////////////////////////////////////////////////////// 1325// time support 1326 1327// Time since start-up in seconds to a fine granularity. 1328// Used by VMSelfDestructTimer and the MemProfiler. 1329double os::elapsedTime() { 1330 1331 return (double)(os::elapsed_counter()) * 0.000001; 1332} 1333 1334jlong os::elapsed_counter() { 1335 timeval time; 1336 int status = gettimeofday(&time, NULL); 1337 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count; 1338} 1339 1340jlong os::elapsed_frequency() { 1341 return (1000 * 1000); 1342} 1343 1344// For now, we say that linux does not support vtime. I have no idea 1345// whether it can actually be made to (DLD, 9/13/05). 1346 1347bool os::supports_vtime() { return false; } 1348bool os::enable_vtime() { return false; } 1349bool os::vtime_enabled() { return false; } 1350double os::elapsedVTime() { 1351 // better than nothing, but not much 1352 return elapsedTime(); 1353} 1354 1355jlong os::javaTimeMillis() { 1356 timeval time; 1357 int status = gettimeofday(&time, NULL); 1358 assert(status != -1, "linux error"); 1359 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1360} 1361 1362#ifndef CLOCK_MONOTONIC 1363#define CLOCK_MONOTONIC (1) 1364#endif 1365 1366void os::Linux::clock_init() { 1367 // we do dlopen's in this particular order due to bug in linux 1368 // dynamical loader (see 6348968) leading to crash on exit 1369 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1370 if (handle == NULL) { 1371 handle = dlopen("librt.so", RTLD_LAZY); 1372 } 1373 1374 if (handle) { 1375 int (*clock_getres_func)(clockid_t, struct timespec*) = 1376 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1377 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1378 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1379 if (clock_getres_func && clock_gettime_func) { 1380 // See if monotonic clock is supported by the kernel. Note that some 1381 // early implementations simply return kernel jiffies (updated every 1382 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1383 // for nano time (though the monotonic property is still nice to have). 1384 // It's fixed in newer kernels, however clock_getres() still returns 1385 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1386 // resolution for now. Hopefully as people move to new kernels, this 1387 // won't be a problem. 1388 struct timespec res; 1389 struct timespec tp; 1390 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1391 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1392 // yes, monotonic clock is supported 1393 _clock_gettime = clock_gettime_func; 1394 } else { 1395 // close librt if there is no monotonic clock 1396 dlclose(handle); 1397 } 1398 } 1399 } 1400} 1401 1402#ifndef SYS_clock_getres 1403 1404#if defined(IA32) || defined(AMD64) 1405#define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1406#define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1407#else 1408#warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1409#define sys_clock_getres(x,y) -1 1410#endif 1411 1412#else 1413#define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1414#endif 1415 1416void os::Linux::fast_thread_clock_init() { 1417 if (!UseLinuxPosixThreadCPUClocks) { 1418 return; 1419 } 1420 clockid_t clockid; 1421 struct timespec tp; 1422 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1423 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1424 1425 // Switch to using fast clocks for thread cpu time if 1426 // the sys_clock_getres() returns 0 error code. 1427 // Note, that some kernels may support the current thread 1428 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1429 // returned by the pthread_getcpuclockid(). 1430 // If the fast Posix clocks are supported then the sys_clock_getres() 1431 // must return at least tp.tv_sec == 0 which means a resolution 1432 // better than 1 sec. This is extra check for reliability. 1433 1434 if(pthread_getcpuclockid_func && 1435 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1436 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1437 1438 _supports_fast_thread_cpu_time = true; 1439 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1440 } 1441} 1442 1443jlong os::javaTimeNanos() { 1444 if (Linux::supports_monotonic_clock()) { 1445 struct timespec tp; 1446 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1447 assert(status == 0, "gettime error"); 1448 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1449 return result; 1450 } else { 1451 timeval time; 1452 int status = gettimeofday(&time, NULL); 1453 assert(status != -1, "linux error"); 1454 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1455 return 1000 * usecs; 1456 } 1457} 1458 1459void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1460 if (Linux::supports_monotonic_clock()) { 1461 info_ptr->max_value = ALL_64_BITS; 1462 1463 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1464 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1465 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1466 } else { 1467 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1468 info_ptr->max_value = ALL_64_BITS; 1469 1470 // gettimeofday is a real time clock so it skips 1471 info_ptr->may_skip_backward = true; 1472 info_ptr->may_skip_forward = true; 1473 } 1474 1475 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1476} 1477 1478// Return the real, user, and system times in seconds from an 1479// arbitrary fixed point in the past. 1480bool os::getTimesSecs(double* process_real_time, 1481 double* process_user_time, 1482 double* process_system_time) { 1483 struct tms ticks; 1484 clock_t real_ticks = times(&ticks); 1485 1486 if (real_ticks == (clock_t) (-1)) { 1487 return false; 1488 } else { 1489 double ticks_per_second = (double) clock_tics_per_sec; 1490 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1491 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1492 *process_real_time = ((double) real_ticks) / ticks_per_second; 1493 1494 return true; 1495 } 1496} 1497 1498 1499char * os::local_time_string(char *buf, size_t buflen) { 1500 struct tm t; 1501 time_t long_time; 1502 time(&long_time); 1503 localtime_r(&long_time, &t); 1504 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1505 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1506 t.tm_hour, t.tm_min, t.tm_sec); 1507 return buf; 1508} 1509 1510struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1511 return localtime_r(clock, res); 1512} 1513 1514//////////////////////////////////////////////////////////////////////////////// 1515// runtime exit support 1516 1517// Note: os::shutdown() might be called very early during initialization, or 1518// called from signal handler. Before adding something to os::shutdown(), make 1519// sure it is async-safe and can handle partially initialized VM. 1520void os::shutdown() { 1521 1522 // allow PerfMemory to attempt cleanup of any persistent resources 1523 perfMemory_exit(); 1524 1525 // needs to remove object in file system 1526 AttachListener::abort(); 1527 1528 // flush buffered output, finish log files 1529 ostream_abort(); 1530 1531 // Check for abort hook 1532 abort_hook_t abort_hook = Arguments::abort_hook(); 1533 if (abort_hook != NULL) { 1534 abort_hook(); 1535 } 1536 1537} 1538 1539// Note: os::abort() might be called very early during initialization, or 1540// called from signal handler. Before adding something to os::abort(), make 1541// sure it is async-safe and can handle partially initialized VM. 1542void os::abort(bool dump_core) { 1543 os::shutdown(); 1544 if (dump_core) { 1545#ifndef PRODUCT 1546 fdStream out(defaultStream::output_fd()); 1547 out.print_raw("Current thread is "); 1548 char buf[16]; 1549 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1550 out.print_raw_cr(buf); 1551 out.print_raw_cr("Dumping core ..."); 1552#endif 1553 ::abort(); // dump core 1554 } 1555 1556 ::exit(1); 1557} 1558 1559// Die immediately, no exit hook, no abort hook, no cleanup. 1560void os::die() { 1561 // _exit() on LinuxThreads only kills current thread 1562 ::abort(); 1563} 1564 1565// unused on linux for now. 1566void os::set_error_file(const char *logfile) {} 1567 1568 1569// This method is a copy of JDK's sysGetLastErrorString 1570// from src/solaris/hpi/src/system_md.c 1571 1572size_t os::lasterror(char *buf, size_t len) { 1573 1574 if (errno == 0) return 0; 1575 1576 const char *s = ::strerror(errno); 1577 size_t n = ::strlen(s); 1578 if (n >= len) { 1579 n = len - 1; 1580 } 1581 ::strncpy(buf, s, n); 1582 buf[n] = '\0'; 1583 return n; 1584} 1585 1586intx os::current_thread_id() { return (intx)pthread_self(); } 1587int os::current_process_id() { 1588 1589 // Under the old linux thread library, linux gives each thread 1590 // its own process id. Because of this each thread will return 1591 // a different pid if this method were to return the result 1592 // of getpid(2). Linux provides no api that returns the pid 1593 // of the launcher thread for the vm. This implementation 1594 // returns a unique pid, the pid of the launcher thread 1595 // that starts the vm 'process'. 1596 1597 // Under the NPTL, getpid() returns the same pid as the 1598 // launcher thread rather than a unique pid per thread. 1599 // Use gettid() if you want the old pre NPTL behaviour. 1600 1601 // if you are looking for the result of a call to getpid() that 1602 // returns a unique pid for the calling thread, then look at the 1603 // OSThread::thread_id() method in osThread_linux.hpp file 1604 1605 return (int)(_initial_pid ? _initial_pid : getpid()); 1606} 1607 1608// DLL functions 1609 1610const char* os::dll_file_extension() { return ".so"; } 1611 1612const char* os::get_temp_directory() { 1613 const char *prop = Arguments::get_property("java.io.tmpdir"); 1614 return prop == NULL ? "/tmp" : prop; 1615} 1616 1617static bool file_exists(const char* filename) { 1618 struct stat statbuf; 1619 if (filename == NULL || strlen(filename) == 0) { 1620 return false; 1621 } 1622 return os::stat(filename, &statbuf) == 0; 1623} 1624 1625void os::dll_build_name(char* buffer, size_t buflen, 1626 const char* pname, const char* fname) { 1627 // Copied from libhpi 1628 const size_t pnamelen = pname ? strlen(pname) : 0; 1629 1630 // Quietly truncate on buffer overflow. Should be an error. 1631 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1632 *buffer = '\0'; 1633 return; 1634 } 1635 1636 if (pnamelen == 0) { 1637 snprintf(buffer, buflen, "lib%s.so", fname); 1638 } else if (strchr(pname, *os::path_separator()) != NULL) { 1639 int n; 1640 char** pelements = split_path(pname, &n); 1641 for (int i = 0 ; i < n ; i++) { 1642 // Really shouldn't be NULL, but check can't hurt 1643 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1644 continue; // skip the empty path values 1645 } 1646 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1647 if (file_exists(buffer)) { 1648 break; 1649 } 1650 } 1651 // release the storage 1652 for (int i = 0 ; i < n ; i++) { 1653 if (pelements[i] != NULL) { 1654 FREE_C_HEAP_ARRAY(char, pelements[i]); 1655 } 1656 } 1657 if (pelements != NULL) { 1658 FREE_C_HEAP_ARRAY(char*, pelements); 1659 } 1660 } else { 1661 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1662 } 1663} 1664 1665const char* os::get_current_directory(char *buf, int buflen) { 1666 return getcwd(buf, buflen); 1667} 1668 1669// check if addr is inside libjvm[_g].so 1670bool os::address_is_in_vm(address addr) { 1671 static address libjvm_base_addr; 1672 Dl_info dlinfo; 1673 1674 if (libjvm_base_addr == NULL) { 1675 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo); 1676 libjvm_base_addr = (address)dlinfo.dli_fbase; 1677 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1678 } 1679 1680 if (dladdr((void *)addr, &dlinfo)) { 1681 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1682 } 1683 1684 return false; 1685} 1686 1687bool os::dll_address_to_function_name(address addr, char *buf, 1688 int buflen, int *offset) { 1689 Dl_info dlinfo; 1690 1691 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) { 1692 if (buf != NULL) { 1693 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) { 1694 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1695 } 1696 } 1697 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1698 return true; 1699 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) { 1700 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1701 dlinfo.dli_fname, buf, buflen, offset) == Decoder::no_error) { 1702 return true; 1703 } 1704 } 1705 1706 if (buf != NULL) buf[0] = '\0'; 1707 if (offset != NULL) *offset = -1; 1708 return false; 1709} 1710 1711struct _address_to_library_name { 1712 address addr; // input : memory address 1713 size_t buflen; // size of fname 1714 char* fname; // output: library name 1715 address base; // library base addr 1716}; 1717 1718static int address_to_library_name_callback(struct dl_phdr_info *info, 1719 size_t size, void *data) { 1720 int i; 1721 bool found = false; 1722 address libbase = NULL; 1723 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1724 1725 // iterate through all loadable segments 1726 for (i = 0; i < info->dlpi_phnum; i++) { 1727 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1728 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1729 // base address of a library is the lowest address of its loaded 1730 // segments. 1731 if (libbase == NULL || libbase > segbase) { 1732 libbase = segbase; 1733 } 1734 // see if 'addr' is within current segment 1735 if (segbase <= d->addr && 1736 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1737 found = true; 1738 } 1739 } 1740 } 1741 1742 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1743 // so dll_address_to_library_name() can fall through to use dladdr() which 1744 // can figure out executable name from argv[0]. 1745 if (found && info->dlpi_name && info->dlpi_name[0]) { 1746 d->base = libbase; 1747 if (d->fname) { 1748 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1749 } 1750 return 1; 1751 } 1752 return 0; 1753} 1754 1755bool os::dll_address_to_library_name(address addr, char* buf, 1756 int buflen, int* offset) { 1757 Dl_info dlinfo; 1758 struct _address_to_library_name data; 1759 1760 // There is a bug in old glibc dladdr() implementation that it could resolve 1761 // to wrong library name if the .so file has a base address != NULL. Here 1762 // we iterate through the program headers of all loaded libraries to find 1763 // out which library 'addr' really belongs to. This workaround can be 1764 // removed once the minimum requirement for glibc is moved to 2.3.x. 1765 data.addr = addr; 1766 data.fname = buf; 1767 data.buflen = buflen; 1768 data.base = NULL; 1769 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1770 1771 if (rslt) { 1772 // buf already contains library name 1773 if (offset) *offset = addr - data.base; 1774 return true; 1775 } else if (dladdr((void*)addr, &dlinfo)){ 1776 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1777 if (offset) *offset = addr - (address)dlinfo.dli_fbase; 1778 return true; 1779 } else { 1780 if (buf) buf[0] = '\0'; 1781 if (offset) *offset = -1; 1782 return false; 1783 } 1784} 1785 1786 // Loads .dll/.so and 1787 // in case of error it checks if .dll/.so was built for the 1788 // same architecture as Hotspot is running on 1789 1790void * os::dll_load(const char *filename, char *ebuf, int ebuflen) 1791{ 1792 void * result= ::dlopen(filename, RTLD_LAZY); 1793 if (result != NULL) { 1794 // Successful loading 1795 return result; 1796 } 1797 1798 Elf32_Ehdr elf_head; 1799 1800 // Read system error message into ebuf 1801 // It may or may not be overwritten below 1802 ::strncpy(ebuf, ::dlerror(), ebuflen-1); 1803 ebuf[ebuflen-1]='\0'; 1804 int diag_msg_max_length=ebuflen-strlen(ebuf); 1805 char* diag_msg_buf=ebuf+strlen(ebuf); 1806 1807 if (diag_msg_max_length==0) { 1808 // No more space in ebuf for additional diagnostics message 1809 return NULL; 1810 } 1811 1812 1813 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1814 1815 if (file_descriptor < 0) { 1816 // Can't open library, report dlerror() message 1817 return NULL; 1818 } 1819 1820 bool failed_to_read_elf_head= 1821 (sizeof(elf_head)!= 1822 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ; 1823 1824 ::close(file_descriptor); 1825 if (failed_to_read_elf_head) { 1826 // file i/o error - report dlerror() msg 1827 return NULL; 1828 } 1829 1830 typedef struct { 1831 Elf32_Half code; // Actual value as defined in elf.h 1832 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1833 char elf_class; // 32 or 64 bit 1834 char endianess; // MSB or LSB 1835 char* name; // String representation 1836 } arch_t; 1837 1838 #ifndef EM_486 1839 #define EM_486 6 /* Intel 80486 */ 1840 #endif 1841 1842 static const arch_t arch_array[]={ 1843 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1844 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1845 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1846 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1847 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1848 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1849 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1850 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1851 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1852 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1853 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1854 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1855 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1856 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1857 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1858 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"} 1859 }; 1860 1861 #if (defined IA32) 1862 static Elf32_Half running_arch_code=EM_386; 1863 #elif (defined AMD64) 1864 static Elf32_Half running_arch_code=EM_X86_64; 1865 #elif (defined IA64) 1866 static Elf32_Half running_arch_code=EM_IA_64; 1867 #elif (defined __sparc) && (defined _LP64) 1868 static Elf32_Half running_arch_code=EM_SPARCV9; 1869 #elif (defined __sparc) && (!defined _LP64) 1870 static Elf32_Half running_arch_code=EM_SPARC; 1871 #elif (defined __powerpc64__) 1872 static Elf32_Half running_arch_code=EM_PPC64; 1873 #elif (defined __powerpc__) 1874 static Elf32_Half running_arch_code=EM_PPC; 1875 #elif (defined ARM) 1876 static Elf32_Half running_arch_code=EM_ARM; 1877 #elif (defined S390) 1878 static Elf32_Half running_arch_code=EM_S390; 1879 #elif (defined ALPHA) 1880 static Elf32_Half running_arch_code=EM_ALPHA; 1881 #elif (defined MIPSEL) 1882 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1883 #elif (defined PARISC) 1884 static Elf32_Half running_arch_code=EM_PARISC; 1885 #elif (defined MIPS) 1886 static Elf32_Half running_arch_code=EM_MIPS; 1887 #elif (defined M68K) 1888 static Elf32_Half running_arch_code=EM_68K; 1889 #else 1890 #error Method os::dll_load requires that one of following is defined:\ 1891 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K 1892 #endif 1893 1894 // Identify compatability class for VM's architecture and library's architecture 1895 // Obtain string descriptions for architectures 1896 1897 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1898 int running_arch_index=-1; 1899 1900 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) { 1901 if (running_arch_code == arch_array[i].code) { 1902 running_arch_index = i; 1903 } 1904 if (lib_arch.code == arch_array[i].code) { 1905 lib_arch.compat_class = arch_array[i].compat_class; 1906 lib_arch.name = arch_array[i].name; 1907 } 1908 } 1909 1910 assert(running_arch_index != -1, 1911 "Didn't find running architecture code (running_arch_code) in arch_array"); 1912 if (running_arch_index == -1) { 1913 // Even though running architecture detection failed 1914 // we may still continue with reporting dlerror() message 1915 return NULL; 1916 } 1917 1918 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1919 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1920 return NULL; 1921 } 1922 1923#ifndef S390 1924 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1925 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1926 return NULL; 1927 } 1928#endif // !S390 1929 1930 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1931 if ( lib_arch.name!=NULL ) { 1932 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1933 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1934 lib_arch.name, arch_array[running_arch_index].name); 1935 } else { 1936 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1937 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1938 lib_arch.code, 1939 arch_array[running_arch_index].name); 1940 } 1941 } 1942 1943 return NULL; 1944} 1945 1946/* 1947 * glibc-2.0 libdl is not MT safe. If you are building with any glibc, 1948 * chances are you might want to run the generated bits against glibc-2.0 1949 * libdl.so, so always use locking for any version of glibc. 1950 */ 1951void* os::dll_lookup(void* handle, const char* name) { 1952 pthread_mutex_lock(&dl_mutex); 1953 void* res = dlsym(handle, name); 1954 pthread_mutex_unlock(&dl_mutex); 1955 return res; 1956} 1957 1958 1959static bool _print_ascii_file(const char* filename, outputStream* st) { 1960 int fd = ::open(filename, O_RDONLY); 1961 if (fd == -1) { 1962 return false; 1963 } 1964 1965 char buf[32]; 1966 int bytes; 1967 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 1968 st->print_raw(buf, bytes); 1969 } 1970 1971 ::close(fd); 1972 1973 return true; 1974} 1975 1976void os::print_dll_info(outputStream *st) { 1977 st->print_cr("Dynamic libraries:"); 1978 1979 char fname[32]; 1980 pid_t pid = os::Linux::gettid(); 1981 1982 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1983 1984 if (!_print_ascii_file(fname, st)) { 1985 st->print("Can not get library information for pid = %d\n", pid); 1986 } 1987} 1988 1989 1990void os::print_os_info(outputStream* st) { 1991 st->print("OS:"); 1992 1993 // Try to identify popular distros. 1994 // Most Linux distributions have /etc/XXX-release file, which contains 1995 // the OS version string. Some have more than one /etc/XXX-release file 1996 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.), 1997 // so the order is important. 1998 if (!_print_ascii_file("/etc/mandrake-release", st) && 1999 !_print_ascii_file("/etc/sun-release", st) && 2000 !_print_ascii_file("/etc/redhat-release", st) && 2001 !_print_ascii_file("/etc/SuSE-release", st) && 2002 !_print_ascii_file("/etc/turbolinux-release", st) && 2003 !_print_ascii_file("/etc/gentoo-release", st) && 2004 !_print_ascii_file("/etc/debian_version", st) && 2005 !_print_ascii_file("/etc/ltib-release", st) && 2006 !_print_ascii_file("/etc/angstrom-version", st)) { 2007 st->print("Linux"); 2008 } 2009 st->cr(); 2010 2011 // kernel 2012 st->print("uname:"); 2013 struct utsname name; 2014 uname(&name); 2015 st->print(name.sysname); st->print(" "); 2016 st->print(name.release); st->print(" "); 2017 st->print(name.version); st->print(" "); 2018 st->print(name.machine); 2019 st->cr(); 2020 2021 // Print warning if unsafe chroot environment detected 2022 if (unsafe_chroot_detected) { 2023 st->print("WARNING!! "); 2024 st->print_cr(unstable_chroot_error); 2025 } 2026 2027 // libc, pthread 2028 st->print("libc:"); 2029 st->print(os::Linux::glibc_version()); st->print(" "); 2030 st->print(os::Linux::libpthread_version()); st->print(" "); 2031 if (os::Linux::is_LinuxThreads()) { 2032 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed"); 2033 } 2034 st->cr(); 2035 2036 // rlimit 2037 st->print("rlimit:"); 2038 struct rlimit rlim; 2039 2040 st->print(" STACK "); 2041 getrlimit(RLIMIT_STACK, &rlim); 2042 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2043 else st->print("%uk", rlim.rlim_cur >> 10); 2044 2045 st->print(", CORE "); 2046 getrlimit(RLIMIT_CORE, &rlim); 2047 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2048 else st->print("%uk", rlim.rlim_cur >> 10); 2049 2050 st->print(", NPROC "); 2051 getrlimit(RLIMIT_NPROC, &rlim); 2052 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2053 else st->print("%d", rlim.rlim_cur); 2054 2055 st->print(", NOFILE "); 2056 getrlimit(RLIMIT_NOFILE, &rlim); 2057 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2058 else st->print("%d", rlim.rlim_cur); 2059 2060 st->print(", AS "); 2061 getrlimit(RLIMIT_AS, &rlim); 2062 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2063 else st->print("%uk", rlim.rlim_cur >> 10); 2064 st->cr(); 2065 2066 // load average 2067 st->print("load average:"); 2068 double loadavg[3]; 2069 os::loadavg(loadavg, 3); 2070 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]); 2071 st->cr(); 2072 2073 // meminfo 2074 st->print("\n/proc/meminfo:\n"); 2075 _print_ascii_file("/proc/meminfo", st); 2076 st->cr(); 2077} 2078 2079void os::print_memory_info(outputStream* st) { 2080 2081 st->print("Memory:"); 2082 st->print(" %dk page", os::vm_page_size()>>10); 2083 2084 // values in struct sysinfo are "unsigned long" 2085 struct sysinfo si; 2086 sysinfo(&si); 2087 2088 st->print(", physical " UINT64_FORMAT "k", 2089 os::physical_memory() >> 10); 2090 st->print("(" UINT64_FORMAT "k free)", 2091 os::available_memory() >> 10); 2092 st->print(", swap " UINT64_FORMAT "k", 2093 ((jlong)si.totalswap * si.mem_unit) >> 10); 2094 st->print("(" UINT64_FORMAT "k free)", 2095 ((jlong)si.freeswap * si.mem_unit) >> 10); 2096 st->cr(); 2097} 2098 2099// Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific 2100// but they're the same for all the linux arch that we support 2101// and they're the same for solaris but there's no common place to put this. 2102const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR", 2103 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG", 2104 "ILL_COPROC", "ILL_BADSTK" }; 2105 2106const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV", 2107 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES", 2108 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" }; 2109 2110const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" }; 2111 2112const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" }; 2113 2114void os::print_siginfo(outputStream* st, void* siginfo) { 2115 st->print("siginfo:"); 2116 2117 const int buflen = 100; 2118 char buf[buflen]; 2119 siginfo_t *si = (siginfo_t*)siginfo; 2120 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen)); 2121 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) { 2122 st->print("si_errno=%s", buf); 2123 } else { 2124 st->print("si_errno=%d", si->si_errno); 2125 } 2126 const int c = si->si_code; 2127 assert(c > 0, "unexpected si_code"); 2128 switch (si->si_signo) { 2129 case SIGILL: 2130 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]); 2131 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2132 break; 2133 case SIGFPE: 2134 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]); 2135 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2136 break; 2137 case SIGSEGV: 2138 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]); 2139 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2140 break; 2141 case SIGBUS: 2142 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]); 2143 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2144 break; 2145 default: 2146 st->print(", si_code=%d", si->si_code); 2147 // no si_addr 2148 } 2149 2150 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2151 UseSharedSpaces) { 2152 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2153 if (mapinfo->is_in_shared_space(si->si_addr)) { 2154 st->print("\n\nError accessing class data sharing archive." \ 2155 " Mapped file inaccessible during execution, " \ 2156 " possible disk/network problem."); 2157 } 2158 } 2159 st->cr(); 2160} 2161 2162 2163static void print_signal_handler(outputStream* st, int sig, 2164 char* buf, size_t buflen); 2165 2166void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2167 st->print_cr("Signal Handlers:"); 2168 print_signal_handler(st, SIGSEGV, buf, buflen); 2169 print_signal_handler(st, SIGBUS , buf, buflen); 2170 print_signal_handler(st, SIGFPE , buf, buflen); 2171 print_signal_handler(st, SIGPIPE, buf, buflen); 2172 print_signal_handler(st, SIGXFSZ, buf, buflen); 2173 print_signal_handler(st, SIGILL , buf, buflen); 2174 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2175 print_signal_handler(st, SR_signum, buf, buflen); 2176 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2177 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2178 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2179 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2180} 2181 2182static char saved_jvm_path[MAXPATHLEN] = {0}; 2183 2184// Find the full path to the current module, libjvm.so or libjvm_g.so 2185void os::jvm_path(char *buf, jint buflen) { 2186 // Error checking. 2187 if (buflen < MAXPATHLEN) { 2188 assert(false, "must use a large-enough buffer"); 2189 buf[0] = '\0'; 2190 return; 2191 } 2192 // Lazy resolve the path to current module. 2193 if (saved_jvm_path[0] != 0) { 2194 strcpy(buf, saved_jvm_path); 2195 return; 2196 } 2197 2198 char dli_fname[MAXPATHLEN]; 2199 bool ret = dll_address_to_library_name( 2200 CAST_FROM_FN_PTR(address, os::jvm_path), 2201 dli_fname, sizeof(dli_fname), NULL); 2202 assert(ret != 0, "cannot locate libjvm"); 2203 char *rp = realpath(dli_fname, buf); 2204 if (rp == NULL) 2205 return; 2206 2207 if (strcmp(Arguments::sun_java_launcher(), "gamma") == 0) { 2208 // Support for the gamma launcher. Typical value for buf is 2209 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at 2210 // the right place in the string, then assume we are installed in a JDK and 2211 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix 2212 // up the path so it looks like libjvm.so is installed there (append a 2213 // fake suffix hotspot/libjvm.so). 2214 const char *p = buf + strlen(buf) - 1; 2215 for (int count = 0; p > buf && count < 5; ++count) { 2216 for (--p; p > buf && *p != '/'; --p) 2217 /* empty */ ; 2218 } 2219 2220 if (strncmp(p, "/jre/lib/", 9) != 0) { 2221 // Look for JAVA_HOME in the environment. 2222 char* java_home_var = ::getenv("JAVA_HOME"); 2223 if (java_home_var != NULL && java_home_var[0] != 0) { 2224 char* jrelib_p; 2225 int len; 2226 2227 // Check the current module name "libjvm.so" or "libjvm_g.so". 2228 p = strrchr(buf, '/'); 2229 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2230 p = strstr(p, "_g") ? "_g" : ""; 2231 2232 rp = realpath(java_home_var, buf); 2233 if (rp == NULL) 2234 return; 2235 2236 // determine if this is a legacy image or modules image 2237 // modules image doesn't have "jre" subdirectory 2238 len = strlen(buf); 2239 jrelib_p = buf + len; 2240 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2241 if (0 != access(buf, F_OK)) { 2242 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2243 } 2244 2245 if (0 == access(buf, F_OK)) { 2246 // Use current module name "libjvm[_g].so" instead of 2247 // "libjvm"debug_only("_g")".so" since for fastdebug version 2248 // we should have "libjvm.so" but debug_only("_g") adds "_g"! 2249 len = strlen(buf); 2250 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p); 2251 } else { 2252 // Go back to path of .so 2253 rp = realpath(dli_fname, buf); 2254 if (rp == NULL) 2255 return; 2256 } 2257 } 2258 } 2259 } 2260 2261 strcpy(saved_jvm_path, buf); 2262} 2263 2264void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2265 // no prefix required, not even "_" 2266} 2267 2268void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2269 // no suffix required 2270} 2271 2272//////////////////////////////////////////////////////////////////////////////// 2273// sun.misc.Signal support 2274 2275static volatile jint sigint_count = 0; 2276 2277static void 2278UserHandler(int sig, void *siginfo, void *context) { 2279 // 4511530 - sem_post is serialized and handled by the manager thread. When 2280 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2281 // don't want to flood the manager thread with sem_post requests. 2282 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) 2283 return; 2284 2285 // Ctrl-C is pressed during error reporting, likely because the error 2286 // handler fails to abort. Let VM die immediately. 2287 if (sig == SIGINT && is_error_reported()) { 2288 os::die(); 2289 } 2290 2291 os::signal_notify(sig); 2292} 2293 2294void* os::user_handler() { 2295 return CAST_FROM_FN_PTR(void*, UserHandler); 2296} 2297 2298extern "C" { 2299 typedef void (*sa_handler_t)(int); 2300 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2301} 2302 2303void* os::signal(int signal_number, void* handler) { 2304 struct sigaction sigAct, oldSigAct; 2305 2306 sigfillset(&(sigAct.sa_mask)); 2307 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2308 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2309 2310 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2311 // -1 means registration failed 2312 return (void *)-1; 2313 } 2314 2315 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2316} 2317 2318void os::signal_raise(int signal_number) { 2319 ::raise(signal_number); 2320} 2321 2322/* 2323 * The following code is moved from os.cpp for making this 2324 * code platform specific, which it is by its very nature. 2325 */ 2326 2327// Will be modified when max signal is changed to be dynamic 2328int os::sigexitnum_pd() { 2329 return NSIG; 2330} 2331 2332// a counter for each possible signal value 2333static volatile jint pending_signals[NSIG+1] = { 0 }; 2334 2335// Linux(POSIX) specific hand shaking semaphore. 2336static sem_t sig_sem; 2337 2338void os::signal_init_pd() { 2339 // Initialize signal structures 2340 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2341 2342 // Initialize signal semaphore 2343 ::sem_init(&sig_sem, 0, 0); 2344} 2345 2346void os::signal_notify(int sig) { 2347 Atomic::inc(&pending_signals[sig]); 2348 ::sem_post(&sig_sem); 2349} 2350 2351static int check_pending_signals(bool wait) { 2352 Atomic::store(0, &sigint_count); 2353 for (;;) { 2354 for (int i = 0; i < NSIG + 1; i++) { 2355 jint n = pending_signals[i]; 2356 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2357 return i; 2358 } 2359 } 2360 if (!wait) { 2361 return -1; 2362 } 2363 JavaThread *thread = JavaThread::current(); 2364 ThreadBlockInVM tbivm(thread); 2365 2366 bool threadIsSuspended; 2367 do { 2368 thread->set_suspend_equivalent(); 2369 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2370 ::sem_wait(&sig_sem); 2371 2372 // were we externally suspended while we were waiting? 2373 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2374 if (threadIsSuspended) { 2375 // 2376 // The semaphore has been incremented, but while we were waiting 2377 // another thread suspended us. We don't want to continue running 2378 // while suspended because that would surprise the thread that 2379 // suspended us. 2380 // 2381 ::sem_post(&sig_sem); 2382 2383 thread->java_suspend_self(); 2384 } 2385 } while (threadIsSuspended); 2386 } 2387} 2388 2389int os::signal_lookup() { 2390 return check_pending_signals(false); 2391} 2392 2393int os::signal_wait() { 2394 return check_pending_signals(true); 2395} 2396 2397//////////////////////////////////////////////////////////////////////////////// 2398// Virtual Memory 2399 2400int os::vm_page_size() { 2401 // Seems redundant as all get out 2402 assert(os::Linux::page_size() != -1, "must call os::init"); 2403 return os::Linux::page_size(); 2404} 2405 2406// Solaris allocates memory by pages. 2407int os::vm_allocation_granularity() { 2408 assert(os::Linux::page_size() != -1, "must call os::init"); 2409 return os::Linux::page_size(); 2410} 2411 2412// Rationale behind this function: 2413// current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2414// mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2415// samples for JITted code. Here we create private executable mapping over the code cache 2416// and then we can use standard (well, almost, as mapping can change) way to provide 2417// info for the reporting script by storing timestamp and location of symbol 2418void linux_wrap_code(char* base, size_t size) { 2419 static volatile jint cnt = 0; 2420 2421 if (!UseOprofile) { 2422 return; 2423 } 2424 2425 char buf[PATH_MAX+1]; 2426 int num = Atomic::add(1, &cnt); 2427 2428 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2429 os::get_temp_directory(), os::current_process_id(), num); 2430 unlink(buf); 2431 2432 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2433 2434 if (fd != -1) { 2435 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2436 if (rv != (off_t)-1) { 2437 if (::write(fd, "", 1) == 1) { 2438 mmap(base, size, 2439 PROT_READ|PROT_WRITE|PROT_EXEC, 2440 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2441 } 2442 } 2443 ::close(fd); 2444 unlink(buf); 2445 } 2446} 2447 2448// NOTE: Linux kernel does not really reserve the pages for us. 2449// All it does is to check if there are enough free pages 2450// left at the time of mmap(). This could be a potential 2451// problem. 2452bool os::commit_memory(char* addr, size_t size, bool exec) { 2453 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2454 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2455 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2456 return res != (uintptr_t) MAP_FAILED; 2457} 2458 2459bool os::commit_memory(char* addr, size_t size, size_t alignment_hint, 2460 bool exec) { 2461 return commit_memory(addr, size, exec); 2462} 2463 2464void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { } 2465 2466void os::free_memory(char *addr, size_t bytes) { 2467 ::mmap(addr, bytes, PROT_READ | PROT_WRITE, 2468 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2469} 2470 2471void os::numa_make_global(char *addr, size_t bytes) { 2472 Linux::numa_interleave_memory(addr, bytes); 2473} 2474 2475void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2476 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2477} 2478 2479bool os::numa_topology_changed() { return false; } 2480 2481size_t os::numa_get_groups_num() { 2482 int max_node = Linux::numa_max_node(); 2483 return max_node > 0 ? max_node + 1 : 1; 2484} 2485 2486int os::numa_get_group_id() { 2487 int cpu_id = Linux::sched_getcpu(); 2488 if (cpu_id != -1) { 2489 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2490 if (lgrp_id != -1) { 2491 return lgrp_id; 2492 } 2493 } 2494 return 0; 2495} 2496 2497size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2498 for (size_t i = 0; i < size; i++) { 2499 ids[i] = i; 2500 } 2501 return size; 2502} 2503 2504bool os::get_page_info(char *start, page_info* info) { 2505 return false; 2506} 2507 2508char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) { 2509 return end; 2510} 2511 2512extern "C" void numa_warn(int number, char *where, ...) { } 2513extern "C" void numa_error(char *where) { } 2514 2515 2516// If we are running with libnuma version > 2, then we should 2517// be trying to use symbols with versions 1.1 2518// If we are running with earlier version, which did not have symbol versions, 2519// we should use the base version. 2520void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2521 void *f = dlvsym(handle, name, "libnuma_1.1"); 2522 if (f == NULL) { 2523 f = dlsym(handle, name); 2524 } 2525 return f; 2526} 2527 2528bool os::Linux::libnuma_init() { 2529 // sched_getcpu() should be in libc. 2530 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2531 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2532 2533 if (sched_getcpu() != -1) { // Does it work? 2534 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2535 if (handle != NULL) { 2536 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2537 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2538 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2539 libnuma_dlsym(handle, "numa_max_node"))); 2540 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2541 libnuma_dlsym(handle, "numa_available"))); 2542 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2543 libnuma_dlsym(handle, "numa_tonode_memory"))); 2544 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2545 libnuma_dlsym(handle, "numa_interleave_memory"))); 2546 2547 2548 if (numa_available() != -1) { 2549 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2550 // Create a cpu -> node mapping 2551 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true); 2552 rebuild_cpu_to_node_map(); 2553 return true; 2554 } 2555 } 2556 } 2557 return false; 2558} 2559 2560// rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2561// The table is later used in get_node_by_cpu(). 2562void os::Linux::rebuild_cpu_to_node_map() { 2563 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2564 // in libnuma (possible values are starting from 16, 2565 // and continuing up with every other power of 2, but less 2566 // than the maximum number of CPUs supported by kernel), and 2567 // is a subject to change (in libnuma version 2 the requirements 2568 // are more reasonable) we'll just hardcode the number they use 2569 // in the library. 2570 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2571 2572 size_t cpu_num = os::active_processor_count(); 2573 size_t cpu_map_size = NCPUS / BitsPerCLong; 2574 size_t cpu_map_valid_size = 2575 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2576 2577 cpu_to_node()->clear(); 2578 cpu_to_node()->at_grow(cpu_num - 1); 2579 size_t node_num = numa_get_groups_num(); 2580 2581 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size); 2582 for (size_t i = 0; i < node_num; i++) { 2583 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2584 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2585 if (cpu_map[j] != 0) { 2586 for (size_t k = 0; k < BitsPerCLong; k++) { 2587 if (cpu_map[j] & (1UL << k)) { 2588 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2589 } 2590 } 2591 } 2592 } 2593 } 2594 } 2595 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2596} 2597 2598int os::Linux::get_node_by_cpu(int cpu_id) { 2599 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2600 return cpu_to_node()->at(cpu_id); 2601 } 2602 return -1; 2603} 2604 2605GrowableArray<int>* os::Linux::_cpu_to_node; 2606os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2607os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2608os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2609os::Linux::numa_available_func_t os::Linux::_numa_available; 2610os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2611os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2612unsigned long* os::Linux::_numa_all_nodes; 2613 2614bool os::uncommit_memory(char* addr, size_t size) { 2615 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2616 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2617 return res != (uintptr_t) MAP_FAILED; 2618} 2619 2620// Linux uses a growable mapping for the stack, and if the mapping for 2621// the stack guard pages is not removed when we detach a thread the 2622// stack cannot grow beyond the pages where the stack guard was 2623// mapped. If at some point later in the process the stack expands to 2624// that point, the Linux kernel cannot expand the stack any further 2625// because the guard pages are in the way, and a segfault occurs. 2626// 2627// However, it's essential not to split the stack region by unmapping 2628// a region (leaving a hole) that's already part of the stack mapping, 2629// so if the stack mapping has already grown beyond the guard pages at 2630// the time we create them, we have to truncate the stack mapping. 2631// So, we need to know the extent of the stack mapping when 2632// create_stack_guard_pages() is called. 2633 2634// Find the bounds of the stack mapping. Return true for success. 2635// 2636// We only need this for stacks that are growable: at the time of 2637// writing thread stacks don't use growable mappings (i.e. those 2638// creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2639// only applies to the main thread. 2640static bool 2641get_stack_bounds(uintptr_t *bottom, uintptr_t *top) 2642{ 2643 FILE *f = fopen("/proc/self/maps", "r"); 2644 if (f == NULL) 2645 return false; 2646 2647 while (!feof(f)) { 2648 size_t dummy; 2649 char *str = NULL; 2650 ssize_t len = getline(&str, &dummy, f); 2651 if (len == -1) { 2652 fclose(f); 2653 return false; 2654 } 2655 2656 if (len > 0 && str[len-1] == '\n') { 2657 str[len-1] = 0; 2658 len--; 2659 } 2660 2661 static const char *stack_str = "[stack]"; 2662 if (len > (ssize_t)strlen(stack_str) 2663 && (strcmp(str + len - strlen(stack_str), stack_str) == 0)) { 2664 if (sscanf(str, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) { 2665 uintptr_t sp = (uintptr_t)__builtin_frame_address(0); 2666 if (sp >= *bottom && sp <= *top) { 2667 free(str); 2668 fclose(f); 2669 return true; 2670 } 2671 } 2672 } 2673 free(str); 2674 } 2675 fclose(f); 2676 return false; 2677} 2678 2679// If the (growable) stack mapping already extends beyond the point 2680// where we're going to put our guard pages, truncate the mapping at 2681// that point by munmap()ping it. This ensures that when we later 2682// munmap() the guard pages we don't leave a hole in the stack 2683// mapping. This only affects the main/initial thread, but guard 2684// against future OS changes 2685bool os::create_stack_guard_pages(char* addr, size_t size) { 2686 uintptr_t stack_extent, stack_base; 2687 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2688 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2689 assert(os::Linux::is_initial_thread(), 2690 "growable stack in non-initial thread"); 2691 if (stack_extent < (uintptr_t)addr) 2692 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent); 2693 } 2694 2695 return os::commit_memory(addr, size); 2696} 2697 2698// If this is a growable mapping, remove the guard pages entirely by 2699// munmap()ping them. If not, just call uncommit_memory(). This only 2700// affects the main/initial thread, but guard against future OS changes 2701bool os::remove_stack_guard_pages(char* addr, size_t size) { 2702 uintptr_t stack_extent, stack_base; 2703 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2704 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2705 assert(os::Linux::is_initial_thread(), 2706 "growable stack in non-initial thread"); 2707 2708 return ::munmap(addr, size) == 0; 2709 } 2710 2711 return os::uncommit_memory(addr, size); 2712} 2713 2714static address _highest_vm_reserved_address = NULL; 2715 2716// If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 2717// at 'requested_addr'. If there are existing memory mappings at the same 2718// location, however, they will be overwritten. If 'fixed' is false, 2719// 'requested_addr' is only treated as a hint, the return value may or 2720// may not start from the requested address. Unlike Linux mmap(), this 2721// function returns NULL to indicate failure. 2722static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 2723 char * addr; 2724 int flags; 2725 2726 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 2727 if (fixed) { 2728 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 2729 flags |= MAP_FIXED; 2730 } 2731 2732 // Map uncommitted pages PROT_READ and PROT_WRITE, change access 2733 // to PROT_EXEC if executable when we commit the page. 2734 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE, 2735 flags, -1, 0); 2736 2737 if (addr != MAP_FAILED) { 2738 // anon_mmap() should only get called during VM initialization, 2739 // don't need lock (actually we can skip locking even it can be called 2740 // from multiple threads, because _highest_vm_reserved_address is just a 2741 // hint about the upper limit of non-stack memory regions.) 2742 if ((address)addr + bytes > _highest_vm_reserved_address) { 2743 _highest_vm_reserved_address = (address)addr + bytes; 2744 } 2745 } 2746 2747 return addr == MAP_FAILED ? NULL : addr; 2748} 2749 2750// Don't update _highest_vm_reserved_address, because there might be memory 2751// regions above addr + size. If so, releasing a memory region only creates 2752// a hole in the address space, it doesn't help prevent heap-stack collision. 2753// 2754static int anon_munmap(char * addr, size_t size) { 2755 return ::munmap(addr, size) == 0; 2756} 2757 2758char* os::reserve_memory(size_t bytes, char* requested_addr, 2759 size_t alignment_hint) { 2760 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 2761} 2762 2763bool os::release_memory(char* addr, size_t size) { 2764 return anon_munmap(addr, size); 2765} 2766 2767static address highest_vm_reserved_address() { 2768 return _highest_vm_reserved_address; 2769} 2770 2771static bool linux_mprotect(char* addr, size_t size, int prot) { 2772 // Linux wants the mprotect address argument to be page aligned. 2773 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 2774 2775 // According to SUSv3, mprotect() should only be used with mappings 2776 // established by mmap(), and mmap() always maps whole pages. Unaligned 2777 // 'addr' likely indicates problem in the VM (e.g. trying to change 2778 // protection of malloc'ed or statically allocated memory). Check the 2779 // caller if you hit this assert. 2780 assert(addr == bottom, "sanity check"); 2781 2782 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 2783 return ::mprotect(bottom, size, prot) == 0; 2784} 2785 2786// Set protections specified 2787bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 2788 bool is_committed) { 2789 unsigned int p = 0; 2790 switch (prot) { 2791 case MEM_PROT_NONE: p = PROT_NONE; break; 2792 case MEM_PROT_READ: p = PROT_READ; break; 2793 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 2794 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 2795 default: 2796 ShouldNotReachHere(); 2797 } 2798 // is_committed is unused. 2799 return linux_mprotect(addr, bytes, p); 2800} 2801 2802bool os::guard_memory(char* addr, size_t size) { 2803 return linux_mprotect(addr, size, PROT_NONE); 2804} 2805 2806bool os::unguard_memory(char* addr, size_t size) { 2807 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 2808} 2809 2810// Large page support 2811 2812static size_t _large_page_size = 0; 2813 2814bool os::large_page_init() { 2815 if (!UseLargePages) return false; 2816 2817 if (LargePageSizeInBytes) { 2818 _large_page_size = LargePageSizeInBytes; 2819 } else { 2820 // large_page_size on Linux is used to round up heap size. x86 uses either 2821 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 2822 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 2823 // page as large as 256M. 2824 // 2825 // Here we try to figure out page size by parsing /proc/meminfo and looking 2826 // for a line with the following format: 2827 // Hugepagesize: 2048 kB 2828 // 2829 // If we can't determine the value (e.g. /proc is not mounted, or the text 2830 // format has been changed), we'll use the largest page size supported by 2831 // the processor. 2832 2833#ifndef ZERO 2834 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 2835 ARM_ONLY(2 * M) PPC_ONLY(4 * M); 2836#endif // ZERO 2837 2838 FILE *fp = fopen("/proc/meminfo", "r"); 2839 if (fp) { 2840 while (!feof(fp)) { 2841 int x = 0; 2842 char buf[16]; 2843 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 2844 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 2845 _large_page_size = x * K; 2846 break; 2847 } 2848 } else { 2849 // skip to next line 2850 for (;;) { 2851 int ch = fgetc(fp); 2852 if (ch == EOF || ch == (int)'\n') break; 2853 } 2854 } 2855 } 2856 fclose(fp); 2857 } 2858 } 2859 2860 const size_t default_page_size = (size_t)Linux::page_size(); 2861 if (_large_page_size > default_page_size) { 2862 _page_sizes[0] = _large_page_size; 2863 _page_sizes[1] = default_page_size; 2864 _page_sizes[2] = 0; 2865 } 2866 2867 // Large page support is available on 2.6 or newer kernel, some vendors 2868 // (e.g. Redhat) have backported it to their 2.4 based distributions. 2869 // We optimistically assume the support is available. If later it turns out 2870 // not true, VM will automatically switch to use regular page size. 2871 return true; 2872} 2873 2874#ifndef SHM_HUGETLB 2875#define SHM_HUGETLB 04000 2876#endif 2877 2878char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) { 2879 // "exec" is passed in but not used. Creating the shared image for 2880 // the code cache doesn't have an SHM_X executable permission to check. 2881 assert(UseLargePages, "only for large pages"); 2882 2883 key_t key = IPC_PRIVATE; 2884 char *addr; 2885 2886 bool warn_on_failure = UseLargePages && 2887 (!FLAG_IS_DEFAULT(UseLargePages) || 2888 !FLAG_IS_DEFAULT(LargePageSizeInBytes) 2889 ); 2890 char msg[128]; 2891 2892 // Create a large shared memory region to attach to based on size. 2893 // Currently, size is the total size of the heap 2894 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 2895 if (shmid == -1) { 2896 // Possible reasons for shmget failure: 2897 // 1. shmmax is too small for Java heap. 2898 // > check shmmax value: cat /proc/sys/kernel/shmmax 2899 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 2900 // 2. not enough large page memory. 2901 // > check available large pages: cat /proc/meminfo 2902 // > increase amount of large pages: 2903 // echo new_value > /proc/sys/vm/nr_hugepages 2904 // Note 1: different Linux may use different name for this property, 2905 // e.g. on Redhat AS-3 it is "hugetlb_pool". 2906 // Note 2: it's possible there's enough physical memory available but 2907 // they are so fragmented after a long run that they can't 2908 // coalesce into large pages. Try to reserve large pages when 2909 // the system is still "fresh". 2910 if (warn_on_failure) { 2911 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 2912 warning(msg); 2913 } 2914 return NULL; 2915 } 2916 2917 // attach to the region 2918 addr = (char*)shmat(shmid, req_addr, 0); 2919 int err = errno; 2920 2921 // Remove shmid. If shmat() is successful, the actual shared memory segment 2922 // will be deleted when it's detached by shmdt() or when the process 2923 // terminates. If shmat() is not successful this will remove the shared 2924 // segment immediately. 2925 shmctl(shmid, IPC_RMID, NULL); 2926 2927 if ((intptr_t)addr == -1) { 2928 if (warn_on_failure) { 2929 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 2930 warning(msg); 2931 } 2932 return NULL; 2933 } 2934 2935 return addr; 2936} 2937 2938bool os::release_memory_special(char* base, size_t bytes) { 2939 // detaching the SHM segment will also delete it, see reserve_memory_special() 2940 int rslt = shmdt(base); 2941 return rslt == 0; 2942} 2943 2944size_t os::large_page_size() { 2945 return _large_page_size; 2946} 2947 2948// Linux does not support anonymous mmap with large page memory. The only way 2949// to reserve large page memory without file backing is through SysV shared 2950// memory API. The entire memory region is committed and pinned upfront. 2951// Hopefully this will change in the future... 2952bool os::can_commit_large_page_memory() { 2953 return false; 2954} 2955 2956bool os::can_execute_large_page_memory() { 2957 return false; 2958} 2959 2960// Reserve memory at an arbitrary address, only if that area is 2961// available (and not reserved for something else). 2962 2963char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 2964 const int max_tries = 10; 2965 char* base[max_tries]; 2966 size_t size[max_tries]; 2967 const size_t gap = 0x000000; 2968 2969 // Assert only that the size is a multiple of the page size, since 2970 // that's all that mmap requires, and since that's all we really know 2971 // about at this low abstraction level. If we need higher alignment, 2972 // we can either pass an alignment to this method or verify alignment 2973 // in one of the methods further up the call chain. See bug 5044738. 2974 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 2975 2976 // Repeatedly allocate blocks until the block is allocated at the 2977 // right spot. Give up after max_tries. Note that reserve_memory() will 2978 // automatically update _highest_vm_reserved_address if the call is 2979 // successful. The variable tracks the highest memory address every reserved 2980 // by JVM. It is used to detect heap-stack collision if running with 2981 // fixed-stack LinuxThreads. Because here we may attempt to reserve more 2982 // space than needed, it could confuse the collision detecting code. To 2983 // solve the problem, save current _highest_vm_reserved_address and 2984 // calculate the correct value before return. 2985 address old_highest = _highest_vm_reserved_address; 2986 2987 // Linux mmap allows caller to pass an address as hint; give it a try first, 2988 // if kernel honors the hint then we can return immediately. 2989 char * addr = anon_mmap(requested_addr, bytes, false); 2990 if (addr == requested_addr) { 2991 return requested_addr; 2992 } 2993 2994 if (addr != NULL) { 2995 // mmap() is successful but it fails to reserve at the requested address 2996 anon_munmap(addr, bytes); 2997 } 2998 2999 int i; 3000 for (i = 0; i < max_tries; ++i) { 3001 base[i] = reserve_memory(bytes); 3002 3003 if (base[i] != NULL) { 3004 // Is this the block we wanted? 3005 if (base[i] == requested_addr) { 3006 size[i] = bytes; 3007 break; 3008 } 3009 3010 // Does this overlap the block we wanted? Give back the overlapped 3011 // parts and try again. 3012 3013 size_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3014 if (top_overlap >= 0 && top_overlap < bytes) { 3015 unmap_memory(base[i], top_overlap); 3016 base[i] += top_overlap; 3017 size[i] = bytes - top_overlap; 3018 } else { 3019 size_t bottom_overlap = base[i] + bytes - requested_addr; 3020 if (bottom_overlap >= 0 && bottom_overlap < bytes) { 3021 unmap_memory(requested_addr, bottom_overlap); 3022 size[i] = bytes - bottom_overlap; 3023 } else { 3024 size[i] = bytes; 3025 } 3026 } 3027 } 3028 } 3029 3030 // Give back the unused reserved pieces. 3031 3032 for (int j = 0; j < i; ++j) { 3033 if (base[j] != NULL) { 3034 unmap_memory(base[j], size[j]); 3035 } 3036 } 3037 3038 if (i < max_tries) { 3039 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes); 3040 return requested_addr; 3041 } else { 3042 _highest_vm_reserved_address = old_highest; 3043 return NULL; 3044 } 3045} 3046 3047size_t os::read(int fd, void *buf, unsigned int nBytes) { 3048 return ::read(fd, buf, nBytes); 3049} 3050 3051// TODO-FIXME: reconcile Solaris' os::sleep with the linux variation. 3052// Solaris uses poll(), linux uses park(). 3053// Poll() is likely a better choice, assuming that Thread.interrupt() 3054// generates a SIGUSRx signal. Note that SIGUSR1 can interfere with 3055// SIGSEGV, see 4355769. 3056 3057const int NANOSECS_PER_MILLISECS = 1000000; 3058 3059int os::sleep(Thread* thread, jlong millis, bool interruptible) { 3060 assert(thread == Thread::current(), "thread consistency check"); 3061 3062 ParkEvent * const slp = thread->_SleepEvent ; 3063 slp->reset() ; 3064 OrderAccess::fence() ; 3065 3066 if (interruptible) { 3067 jlong prevtime = javaTimeNanos(); 3068 3069 for (;;) { 3070 if (os::is_interrupted(thread, true)) { 3071 return OS_INTRPT; 3072 } 3073 3074 jlong newtime = javaTimeNanos(); 3075 3076 if (newtime - prevtime < 0) { 3077 // time moving backwards, should only happen if no monotonic clock 3078 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3079 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3080 } else { 3081 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS; 3082 } 3083 3084 if(millis <= 0) { 3085 return OS_OK; 3086 } 3087 3088 prevtime = newtime; 3089 3090 { 3091 assert(thread->is_Java_thread(), "sanity check"); 3092 JavaThread *jt = (JavaThread *) thread; 3093 ThreadBlockInVM tbivm(jt); 3094 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 3095 3096 jt->set_suspend_equivalent(); 3097 // cleared by handle_special_suspend_equivalent_condition() or 3098 // java_suspend_self() via check_and_wait_while_suspended() 3099 3100 slp->park(millis); 3101 3102 // were we externally suspended while we were waiting? 3103 jt->check_and_wait_while_suspended(); 3104 } 3105 } 3106 } else { 3107 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 3108 jlong prevtime = javaTimeNanos(); 3109 3110 for (;;) { 3111 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 3112 // the 1st iteration ... 3113 jlong newtime = javaTimeNanos(); 3114 3115 if (newtime - prevtime < 0) { 3116 // time moving backwards, should only happen if no monotonic clock 3117 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3118 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3119 } else { 3120 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS; 3121 } 3122 3123 if(millis <= 0) break ; 3124 3125 prevtime = newtime; 3126 slp->park(millis); 3127 } 3128 return OS_OK ; 3129 } 3130} 3131 3132int os::naked_sleep() { 3133 // %% make the sleep time an integer flag. for now use 1 millisec. 3134 return os::sleep(Thread::current(), 1, false); 3135} 3136 3137// Sleep forever; naked call to OS-specific sleep; use with CAUTION 3138void os::infinite_sleep() { 3139 while (true) { // sleep forever ... 3140 ::sleep(100); // ... 100 seconds at a time 3141 } 3142} 3143 3144// Used to convert frequent JVM_Yield() to nops 3145bool os::dont_yield() { 3146 return DontYieldALot; 3147} 3148 3149void os::yield() { 3150 sched_yield(); 3151} 3152 3153os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;} 3154 3155void os::yield_all(int attempts) { 3156 // Yields to all threads, including threads with lower priorities 3157 // Threads on Linux are all with same priority. The Solaris style 3158 // os::yield_all() with nanosleep(1ms) is not necessary. 3159 sched_yield(); 3160} 3161 3162// Called from the tight loops to possibly influence time-sharing heuristics 3163void os::loop_breaker(int attempts) { 3164 os::yield_all(attempts); 3165} 3166 3167//////////////////////////////////////////////////////////////////////////////// 3168// thread priority support 3169 3170// Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3171// only supports dynamic priority, static priority must be zero. For real-time 3172// applications, Linux supports SCHED_RR which allows static priority (1-99). 3173// However, for large multi-threaded applications, SCHED_RR is not only slower 3174// than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3175// of 5 runs - Sep 2005). 3176// 3177// The following code actually changes the niceness of kernel-thread/LWP. It 3178// has an assumption that setpriority() only modifies one kernel-thread/LWP, 3179// not the entire user process, and user level threads are 1:1 mapped to kernel 3180// threads. It has always been the case, but could change in the future. For 3181// this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3182// It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3183 3184int os::java_to_os_priority[MaxPriority + 1] = { 3185 19, // 0 Entry should never be used 3186 3187 4, // 1 MinPriority 3188 3, // 2 3189 2, // 3 3190 3191 1, // 4 3192 0, // 5 NormPriority 3193 -1, // 6 3194 3195 -2, // 7 3196 -3, // 8 3197 -4, // 9 NearMaxPriority 3198 3199 -5 // 10 MaxPriority 3200}; 3201 3202static int prio_init() { 3203 if (ThreadPriorityPolicy == 1) { 3204 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3205 // if effective uid is not root. Perhaps, a more elegant way of doing 3206 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3207 if (geteuid() != 0) { 3208 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3209 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3210 } 3211 ThreadPriorityPolicy = 0; 3212 } 3213 } 3214 return 0; 3215} 3216 3217OSReturn os::set_native_priority(Thread* thread, int newpri) { 3218 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK; 3219 3220 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3221 return (ret == 0) ? OS_OK : OS_ERR; 3222} 3223 3224OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) { 3225 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) { 3226 *priority_ptr = java_to_os_priority[NormPriority]; 3227 return OS_OK; 3228 } 3229 3230 errno = 0; 3231 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3232 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3233} 3234 3235// Hint to the underlying OS that a task switch would not be good. 3236// Void return because it's a hint and can fail. 3237void os::hint_no_preempt() {} 3238 3239//////////////////////////////////////////////////////////////////////////////// 3240// suspend/resume support 3241 3242// the low-level signal-based suspend/resume support is a remnant from the 3243// old VM-suspension that used to be for java-suspension, safepoints etc, 3244// within hotspot. Now there is a single use-case for this: 3245// - calling get_thread_pc() on the VMThread by the flat-profiler task 3246// that runs in the watcher thread. 3247// The remaining code is greatly simplified from the more general suspension 3248// code that used to be used. 3249// 3250// The protocol is quite simple: 3251// - suspend: 3252// - sends a signal to the target thread 3253// - polls the suspend state of the osthread using a yield loop 3254// - target thread signal handler (SR_handler) sets suspend state 3255// and blocks in sigsuspend until continued 3256// - resume: 3257// - sets target osthread state to continue 3258// - sends signal to end the sigsuspend loop in the SR_handler 3259// 3260// Note that the SR_lock plays no role in this suspend/resume protocol. 3261// 3262 3263static void resume_clear_context(OSThread *osthread) { 3264 osthread->set_ucontext(NULL); 3265 osthread->set_siginfo(NULL); 3266 3267 // notify the suspend action is completed, we have now resumed 3268 osthread->sr.clear_suspended(); 3269} 3270 3271static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) { 3272 osthread->set_ucontext(context); 3273 osthread->set_siginfo(siginfo); 3274} 3275 3276// 3277// Handler function invoked when a thread's execution is suspended or 3278// resumed. We have to be careful that only async-safe functions are 3279// called here (Note: most pthread functions are not async safe and 3280// should be avoided.) 3281// 3282// Note: sigwait() is a more natural fit than sigsuspend() from an 3283// interface point of view, but sigwait() prevents the signal hander 3284// from being run. libpthread would get very confused by not having 3285// its signal handlers run and prevents sigwait()'s use with the 3286// mutex granting granting signal. 3287// 3288// Currently only ever called on the VMThread 3289// 3290static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3291 // Save and restore errno to avoid confusing native code with EINTR 3292 // after sigsuspend. 3293 int old_errno = errno; 3294 3295 Thread* thread = Thread::current(); 3296 OSThread* osthread = thread->osthread(); 3297 assert(thread->is_VM_thread(), "Must be VMThread"); 3298 // read current suspend action 3299 int action = osthread->sr.suspend_action(); 3300 if (action == SR_SUSPEND) { 3301 suspend_save_context(osthread, siginfo, context); 3302 3303 // Notify the suspend action is about to be completed. do_suspend() 3304 // waits until SR_SUSPENDED is set and then returns. We will wait 3305 // here for a resume signal and that completes the suspend-other 3306 // action. do_suspend/do_resume is always called as a pair from 3307 // the same thread - so there are no races 3308 3309 // notify the caller 3310 osthread->sr.set_suspended(); 3311 3312 sigset_t suspend_set; // signals for sigsuspend() 3313 3314 // get current set of blocked signals and unblock resume signal 3315 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3316 sigdelset(&suspend_set, SR_signum); 3317 3318 // wait here until we are resumed 3319 do { 3320 sigsuspend(&suspend_set); 3321 // ignore all returns until we get a resume signal 3322 } while (osthread->sr.suspend_action() != SR_CONTINUE); 3323 3324 resume_clear_context(osthread); 3325 3326 } else { 3327 assert(action == SR_CONTINUE, "unexpected sr action"); 3328 // nothing special to do - just leave the handler 3329 } 3330 3331 errno = old_errno; 3332} 3333 3334 3335static int SR_initialize() { 3336 struct sigaction act; 3337 char *s; 3338 /* Get signal number to use for suspend/resume */ 3339 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3340 int sig = ::strtol(s, 0, 10); 3341 if (sig > 0 || sig < _NSIG) { 3342 SR_signum = sig; 3343 } 3344 } 3345 3346 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 3347 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 3348 3349 sigemptyset(&SR_sigset); 3350 sigaddset(&SR_sigset, SR_signum); 3351 3352 /* Set up signal handler for suspend/resume */ 3353 act.sa_flags = SA_RESTART|SA_SIGINFO; 3354 act.sa_handler = (void (*)(int)) SR_handler; 3355 3356 // SR_signum is blocked by default. 3357 // 4528190 - We also need to block pthread restart signal (32 on all 3358 // supported Linux platforms). Note that LinuxThreads need to block 3359 // this signal for all threads to work properly. So we don't have 3360 // to use hard-coded signal number when setting up the mask. 3361 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 3362 3363 if (sigaction(SR_signum, &act, 0) == -1) { 3364 return -1; 3365 } 3366 3367 // Save signal flag 3368 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 3369 return 0; 3370} 3371 3372static int SR_finalize() { 3373 return 0; 3374} 3375 3376 3377// returns true on success and false on error - really an error is fatal 3378// but this seems the normal response to library errors 3379static bool do_suspend(OSThread* osthread) { 3380 // mark as suspended and send signal 3381 osthread->sr.set_suspend_action(SR_SUSPEND); 3382 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3383 assert_status(status == 0, status, "pthread_kill"); 3384 3385 // check status and wait until notified of suspension 3386 if (status == 0) { 3387 for (int i = 0; !osthread->sr.is_suspended(); i++) { 3388 os::yield_all(i); 3389 } 3390 osthread->sr.set_suspend_action(SR_NONE); 3391 return true; 3392 } 3393 else { 3394 osthread->sr.set_suspend_action(SR_NONE); 3395 return false; 3396 } 3397} 3398 3399static void do_resume(OSThread* osthread) { 3400 assert(osthread->sr.is_suspended(), "thread should be suspended"); 3401 osthread->sr.set_suspend_action(SR_CONTINUE); 3402 3403 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3404 assert_status(status == 0, status, "pthread_kill"); 3405 // check status and wait unit notified of resumption 3406 if (status == 0) { 3407 for (int i = 0; osthread->sr.is_suspended(); i++) { 3408 os::yield_all(i); 3409 } 3410 } 3411 osthread->sr.set_suspend_action(SR_NONE); 3412} 3413 3414//////////////////////////////////////////////////////////////////////////////// 3415// interrupt support 3416 3417void os::interrupt(Thread* thread) { 3418 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3419 "possibility of dangling Thread pointer"); 3420 3421 OSThread* osthread = thread->osthread(); 3422 3423 if (!osthread->interrupted()) { 3424 osthread->set_interrupted(true); 3425 // More than one thread can get here with the same value of osthread, 3426 // resulting in multiple notifications. We do, however, want the store 3427 // to interrupted() to be visible to other threads before we execute unpark(). 3428 OrderAccess::fence(); 3429 ParkEvent * const slp = thread->_SleepEvent ; 3430 if (slp != NULL) slp->unpark() ; 3431 } 3432 3433 // For JSR166. Unpark even if interrupt status already was set 3434 if (thread->is_Java_thread()) 3435 ((JavaThread*)thread)->parker()->unpark(); 3436 3437 ParkEvent * ev = thread->_ParkEvent ; 3438 if (ev != NULL) ev->unpark() ; 3439 3440} 3441 3442bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 3443 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3444 "possibility of dangling Thread pointer"); 3445 3446 OSThread* osthread = thread->osthread(); 3447 3448 bool interrupted = osthread->interrupted(); 3449 3450 if (interrupted && clear_interrupted) { 3451 osthread->set_interrupted(false); 3452 // consider thread->_SleepEvent->reset() ... optional optimization 3453 } 3454 3455 return interrupted; 3456} 3457 3458/////////////////////////////////////////////////////////////////////////////////// 3459// signal handling (except suspend/resume) 3460 3461// This routine may be used by user applications as a "hook" to catch signals. 3462// The user-defined signal handler must pass unrecognized signals to this 3463// routine, and if it returns true (non-zero), then the signal handler must 3464// return immediately. If the flag "abort_if_unrecognized" is true, then this 3465// routine will never retun false (zero), but instead will execute a VM panic 3466// routine kill the process. 3467// 3468// If this routine returns false, it is OK to call it again. This allows 3469// the user-defined signal handler to perform checks either before or after 3470// the VM performs its own checks. Naturally, the user code would be making 3471// a serious error if it tried to handle an exception (such as a null check 3472// or breakpoint) that the VM was generating for its own correct operation. 3473// 3474// This routine may recognize any of the following kinds of signals: 3475// SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 3476// It should be consulted by handlers for any of those signals. 3477// 3478// The caller of this routine must pass in the three arguments supplied 3479// to the function referred to in the "sa_sigaction" (not the "sa_handler") 3480// field of the structure passed to sigaction(). This routine assumes that 3481// the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 3482// 3483// Note that the VM will print warnings if it detects conflicting signal 3484// handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 3485// 3486extern "C" int 3487JVM_handle_linux_signal(int signo, siginfo_t* siginfo, 3488 void* ucontext, int abort_if_unrecognized); 3489 3490void signalHandler(int sig, siginfo_t* info, void* uc) { 3491 assert(info != NULL && uc != NULL, "it must be old kernel"); 3492 JVM_handle_linux_signal(sig, info, uc, true); 3493} 3494 3495 3496// This boolean allows users to forward their own non-matching signals 3497// to JVM_handle_linux_signal, harmlessly. 3498bool os::Linux::signal_handlers_are_installed = false; 3499 3500// For signal-chaining 3501struct sigaction os::Linux::sigact[MAXSIGNUM]; 3502unsigned int os::Linux::sigs = 0; 3503bool os::Linux::libjsig_is_loaded = false; 3504typedef struct sigaction *(*get_signal_t)(int); 3505get_signal_t os::Linux::get_signal_action = NULL; 3506 3507struct sigaction* os::Linux::get_chained_signal_action(int sig) { 3508 struct sigaction *actp = NULL; 3509 3510 if (libjsig_is_loaded) { 3511 // Retrieve the old signal handler from libjsig 3512 actp = (*get_signal_action)(sig); 3513 } 3514 if (actp == NULL) { 3515 // Retrieve the preinstalled signal handler from jvm 3516 actp = get_preinstalled_handler(sig); 3517 } 3518 3519 return actp; 3520} 3521 3522static bool call_chained_handler(struct sigaction *actp, int sig, 3523 siginfo_t *siginfo, void *context) { 3524 // Call the old signal handler 3525 if (actp->sa_handler == SIG_DFL) { 3526 // It's more reasonable to let jvm treat it as an unexpected exception 3527 // instead of taking the default action. 3528 return false; 3529 } else if (actp->sa_handler != SIG_IGN) { 3530 if ((actp->sa_flags & SA_NODEFER) == 0) { 3531 // automaticlly block the signal 3532 sigaddset(&(actp->sa_mask), sig); 3533 } 3534 3535 sa_handler_t hand; 3536 sa_sigaction_t sa; 3537 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 3538 // retrieve the chained handler 3539 if (siginfo_flag_set) { 3540 sa = actp->sa_sigaction; 3541 } else { 3542 hand = actp->sa_handler; 3543 } 3544 3545 if ((actp->sa_flags & SA_RESETHAND) != 0) { 3546 actp->sa_handler = SIG_DFL; 3547 } 3548 3549 // try to honor the signal mask 3550 sigset_t oset; 3551 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 3552 3553 // call into the chained handler 3554 if (siginfo_flag_set) { 3555 (*sa)(sig, siginfo, context); 3556 } else { 3557 (*hand)(sig); 3558 } 3559 3560 // restore the signal mask 3561 pthread_sigmask(SIG_SETMASK, &oset, 0); 3562 } 3563 // Tell jvm's signal handler the signal is taken care of. 3564 return true; 3565} 3566 3567bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 3568 bool chained = false; 3569 // signal-chaining 3570 if (UseSignalChaining) { 3571 struct sigaction *actp = get_chained_signal_action(sig); 3572 if (actp != NULL) { 3573 chained = call_chained_handler(actp, sig, siginfo, context); 3574 } 3575 } 3576 return chained; 3577} 3578 3579struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 3580 if ((( (unsigned int)1 << sig ) & sigs) != 0) { 3581 return &sigact[sig]; 3582 } 3583 return NULL; 3584} 3585 3586void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 3587 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3588 sigact[sig] = oldAct; 3589 sigs |= (unsigned int)1 << sig; 3590} 3591 3592// for diagnostic 3593int os::Linux::sigflags[MAXSIGNUM]; 3594 3595int os::Linux::get_our_sigflags(int sig) { 3596 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3597 return sigflags[sig]; 3598} 3599 3600void os::Linux::set_our_sigflags(int sig, int flags) { 3601 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3602 sigflags[sig] = flags; 3603} 3604 3605void os::Linux::set_signal_handler(int sig, bool set_installed) { 3606 // Check for overwrite. 3607 struct sigaction oldAct; 3608 sigaction(sig, (struct sigaction*)NULL, &oldAct); 3609 3610 void* oldhand = oldAct.sa_sigaction 3611 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3612 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3613 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 3614 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 3615 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 3616 if (AllowUserSignalHandlers || !set_installed) { 3617 // Do not overwrite; user takes responsibility to forward to us. 3618 return; 3619 } else if (UseSignalChaining) { 3620 // save the old handler in jvm 3621 save_preinstalled_handler(sig, oldAct); 3622 // libjsig also interposes the sigaction() call below and saves the 3623 // old sigaction on it own. 3624 } else { 3625 fatal(err_msg("Encountered unexpected pre-existing sigaction handler " 3626 "%#lx for signal %d.", (long)oldhand, sig)); 3627 } 3628 } 3629 3630 struct sigaction sigAct; 3631 sigfillset(&(sigAct.sa_mask)); 3632 sigAct.sa_handler = SIG_DFL; 3633 if (!set_installed) { 3634 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3635 } else { 3636 sigAct.sa_sigaction = signalHandler; 3637 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3638 } 3639 // Save flags, which are set by ours 3640 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3641 sigflags[sig] = sigAct.sa_flags; 3642 3643 int ret = sigaction(sig, &sigAct, &oldAct); 3644 assert(ret == 0, "check"); 3645 3646 void* oldhand2 = oldAct.sa_sigaction 3647 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3648 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3649 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 3650} 3651 3652// install signal handlers for signals that HotSpot needs to 3653// handle in order to support Java-level exception handling. 3654 3655void os::Linux::install_signal_handlers() { 3656 if (!signal_handlers_are_installed) { 3657 signal_handlers_are_installed = true; 3658 3659 // signal-chaining 3660 typedef void (*signal_setting_t)(); 3661 signal_setting_t begin_signal_setting = NULL; 3662 signal_setting_t end_signal_setting = NULL; 3663 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3664 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 3665 if (begin_signal_setting != NULL) { 3666 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3667 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 3668 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 3669 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 3670 libjsig_is_loaded = true; 3671 assert(UseSignalChaining, "should enable signal-chaining"); 3672 } 3673 if (libjsig_is_loaded) { 3674 // Tell libjsig jvm is setting signal handlers 3675 (*begin_signal_setting)(); 3676 } 3677 3678 set_signal_handler(SIGSEGV, true); 3679 set_signal_handler(SIGPIPE, true); 3680 set_signal_handler(SIGBUS, true); 3681 set_signal_handler(SIGILL, true); 3682 set_signal_handler(SIGFPE, true); 3683 set_signal_handler(SIGXFSZ, true); 3684 3685 if (libjsig_is_loaded) { 3686 // Tell libjsig jvm finishes setting signal handlers 3687 (*end_signal_setting)(); 3688 } 3689 3690 // We don't activate signal checker if libjsig is in place, we trust ourselves 3691 // and if UserSignalHandler is installed all bets are off 3692 if (CheckJNICalls) { 3693 if (libjsig_is_loaded) { 3694 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 3695 check_signals = false; 3696 } 3697 if (AllowUserSignalHandlers) { 3698 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 3699 check_signals = false; 3700 } 3701 } 3702 } 3703} 3704 3705// This is the fastest way to get thread cpu time on Linux. 3706// Returns cpu time (user+sys) for any thread, not only for current. 3707// POSIX compliant clocks are implemented in the kernels 2.6.16+. 3708// It might work on 2.6.10+ with a special kernel/glibc patch. 3709// For reference, please, see IEEE Std 1003.1-2004: 3710// http://www.unix.org/single_unix_specification 3711 3712jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 3713 struct timespec tp; 3714 int rc = os::Linux::clock_gettime(clockid, &tp); 3715 assert(rc == 0, "clock_gettime is expected to return 0 code"); 3716 3717 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec; 3718} 3719 3720///// 3721// glibc on Linux platform uses non-documented flag 3722// to indicate, that some special sort of signal 3723// trampoline is used. 3724// We will never set this flag, and we should 3725// ignore this flag in our diagnostic 3726#ifdef SIGNIFICANT_SIGNAL_MASK 3727#undef SIGNIFICANT_SIGNAL_MASK 3728#endif 3729#define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 3730 3731static const char* get_signal_handler_name(address handler, 3732 char* buf, int buflen) { 3733 int offset; 3734 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 3735 if (found) { 3736 // skip directory names 3737 const char *p1, *p2; 3738 p1 = buf; 3739 size_t len = strlen(os::file_separator()); 3740 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 3741 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 3742 } else { 3743 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 3744 } 3745 return buf; 3746} 3747 3748static void print_signal_handler(outputStream* st, int sig, 3749 char* buf, size_t buflen) { 3750 struct sigaction sa; 3751 3752 sigaction(sig, NULL, &sa); 3753 3754 // See comment for SIGNIFICANT_SIGNAL_MASK define 3755 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3756 3757 st->print("%s: ", os::exception_name(sig, buf, buflen)); 3758 3759 address handler = (sa.sa_flags & SA_SIGINFO) 3760 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 3761 : CAST_FROM_FN_PTR(address, sa.sa_handler); 3762 3763 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 3764 st->print("SIG_DFL"); 3765 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 3766 st->print("SIG_IGN"); 3767 } else { 3768 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 3769 } 3770 3771 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask); 3772 3773 address rh = VMError::get_resetted_sighandler(sig); 3774 // May be, handler was resetted by VMError? 3775 if(rh != NULL) { 3776 handler = rh; 3777 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 3778 } 3779 3780 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags); 3781 3782 // Check: is it our handler? 3783 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 3784 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 3785 // It is our signal handler 3786 // check for flags, reset system-used one! 3787 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 3788 st->print( 3789 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 3790 os::Linux::get_our_sigflags(sig)); 3791 } 3792 } 3793 st->cr(); 3794} 3795 3796 3797#define DO_SIGNAL_CHECK(sig) \ 3798 if (!sigismember(&check_signal_done, sig)) \ 3799 os::Linux::check_signal_handler(sig) 3800 3801// This method is a periodic task to check for misbehaving JNI applications 3802// under CheckJNI, we can add any periodic checks here 3803 3804void os::run_periodic_checks() { 3805 3806 if (check_signals == false) return; 3807 3808 // SEGV and BUS if overridden could potentially prevent 3809 // generation of hs*.log in the event of a crash, debugging 3810 // such a case can be very challenging, so we absolutely 3811 // check the following for a good measure: 3812 DO_SIGNAL_CHECK(SIGSEGV); 3813 DO_SIGNAL_CHECK(SIGILL); 3814 DO_SIGNAL_CHECK(SIGFPE); 3815 DO_SIGNAL_CHECK(SIGBUS); 3816 DO_SIGNAL_CHECK(SIGPIPE); 3817 DO_SIGNAL_CHECK(SIGXFSZ); 3818 3819 3820 // ReduceSignalUsage allows the user to override these handlers 3821 // see comments at the very top and jvm_solaris.h 3822 if (!ReduceSignalUsage) { 3823 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 3824 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 3825 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 3826 DO_SIGNAL_CHECK(BREAK_SIGNAL); 3827 } 3828 3829 DO_SIGNAL_CHECK(SR_signum); 3830 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 3831} 3832 3833typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 3834 3835static os_sigaction_t os_sigaction = NULL; 3836 3837void os::Linux::check_signal_handler(int sig) { 3838 char buf[O_BUFLEN]; 3839 address jvmHandler = NULL; 3840 3841 3842 struct sigaction act; 3843 if (os_sigaction == NULL) { 3844 // only trust the default sigaction, in case it has been interposed 3845 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 3846 if (os_sigaction == NULL) return; 3847 } 3848 3849 os_sigaction(sig, (struct sigaction*)NULL, &act); 3850 3851 3852 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3853 3854 address thisHandler = (act.sa_flags & SA_SIGINFO) 3855 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 3856 : CAST_FROM_FN_PTR(address, act.sa_handler) ; 3857 3858 3859 switch(sig) { 3860 case SIGSEGV: 3861 case SIGBUS: 3862 case SIGFPE: 3863 case SIGPIPE: 3864 case SIGILL: 3865 case SIGXFSZ: 3866 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 3867 break; 3868 3869 case SHUTDOWN1_SIGNAL: 3870 case SHUTDOWN2_SIGNAL: 3871 case SHUTDOWN3_SIGNAL: 3872 case BREAK_SIGNAL: 3873 jvmHandler = (address)user_handler(); 3874 break; 3875 3876 case INTERRUPT_SIGNAL: 3877 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 3878 break; 3879 3880 default: 3881 if (sig == SR_signum) { 3882 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 3883 } else { 3884 return; 3885 } 3886 break; 3887 } 3888 3889 if (thisHandler != jvmHandler) { 3890 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 3891 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 3892 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 3893 // No need to check this sig any longer 3894 sigaddset(&check_signal_done, sig); 3895 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 3896 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 3897 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 3898 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 3899 // No need to check this sig any longer 3900 sigaddset(&check_signal_done, sig); 3901 } 3902 3903 // Dump all the signal 3904 if (sigismember(&check_signal_done, sig)) { 3905 print_signal_handlers(tty, buf, O_BUFLEN); 3906 } 3907} 3908 3909extern void report_error(char* file_name, int line_no, char* title, char* format, ...); 3910 3911extern bool signal_name(int signo, char* buf, size_t len); 3912 3913const char* os::exception_name(int exception_code, char* buf, size_t size) { 3914 if (0 < exception_code && exception_code <= SIGRTMAX) { 3915 // signal 3916 if (!signal_name(exception_code, buf, size)) { 3917 jio_snprintf(buf, size, "SIG%d", exception_code); 3918 } 3919 return buf; 3920 } else { 3921 return NULL; 3922 } 3923} 3924 3925// this is called _before_ the most of global arguments have been parsed 3926void os::init(void) { 3927 char dummy; /* used to get a guess on initial stack address */ 3928// first_hrtime = gethrtime(); 3929 3930 // With LinuxThreads the JavaMain thread pid (primordial thread) 3931 // is different than the pid of the java launcher thread. 3932 // So, on Linux, the launcher thread pid is passed to the VM 3933 // via the sun.java.launcher.pid property. 3934 // Use this property instead of getpid() if it was correctly passed. 3935 // See bug 6351349. 3936 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid(); 3937 3938 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid(); 3939 3940 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 3941 3942 init_random(1234567); 3943 3944 ThreadCritical::initialize(); 3945 3946 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 3947 if (Linux::page_size() == -1) { 3948 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)", 3949 strerror(errno))); 3950 } 3951 init_page_sizes((size_t) Linux::page_size()); 3952 3953 Linux::initialize_system_info(); 3954 3955 // main_thread points to the aboriginal thread 3956 Linux::_main_thread = pthread_self(); 3957 3958 Linux::clock_init(); 3959 initial_time_count = os::elapsed_counter(); 3960 pthread_mutex_init(&dl_mutex, NULL); 3961} 3962 3963// To install functions for atexit system call 3964extern "C" { 3965 static void perfMemory_exit_helper() { 3966 perfMemory_exit(); 3967 } 3968} 3969 3970// this is called _after_ the global arguments have been parsed 3971jint os::init_2(void) 3972{ 3973 Linux::fast_thread_clock_init(); 3974 3975 // Allocate a single page and mark it as readable for safepoint polling 3976 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 3977 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" ); 3978 3979 os::set_polling_page( polling_page ); 3980 3981#ifndef PRODUCT 3982 if(Verbose && PrintMiscellaneous) 3983 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page); 3984#endif 3985 3986 if (!UseMembar) { 3987 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 3988 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page"); 3989 os::set_memory_serialize_page( mem_serialize_page ); 3990 3991#ifndef PRODUCT 3992 if(Verbose && PrintMiscellaneous) 3993 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page); 3994#endif 3995 } 3996 3997 FLAG_SET_DEFAULT(UseLargePages, os::large_page_init()); 3998 3999 // initialize suspend/resume support - must do this before signal_sets_init() 4000 if (SR_initialize() != 0) { 4001 perror("SR_initialize failed"); 4002 return JNI_ERR; 4003 } 4004 4005 Linux::signal_sets_init(); 4006 Linux::install_signal_handlers(); 4007 4008 // Check minimum allowable stack size for thread creation and to initialize 4009 // the java system classes, including StackOverflowError - depends on page 4010 // size. Add a page for compiler2 recursion in main thread. 4011 // Add in 2*BytesPerWord times page size to account for VM stack during 4012 // class initialization depending on 32 or 64 bit VM. 4013 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4014 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+ 4015 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size()); 4016 4017 size_t threadStackSizeInBytes = ThreadStackSize * K; 4018 if (threadStackSizeInBytes != 0 && 4019 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4020 tty->print_cr("\nThe stack size specified is too small, " 4021 "Specify at least %dk", 4022 os::Linux::min_stack_allowed/ K); 4023 return JNI_ERR; 4024 } 4025 4026 // Make the stack size a multiple of the page size so that 4027 // the yellow/red zones can be guarded. 4028 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4029 vm_page_size())); 4030 4031 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4032 4033 Linux::libpthread_init(); 4034 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4035 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n", 4036 Linux::glibc_version(), Linux::libpthread_version(), 4037 Linux::is_floating_stack() ? "floating stack" : "fixed stack"); 4038 } 4039 4040 if (UseNUMA) { 4041 if (!Linux::libnuma_init()) { 4042 UseNUMA = false; 4043 } else { 4044 if ((Linux::numa_max_node() < 1)) { 4045 // There's only one node(they start from 0), disable NUMA. 4046 UseNUMA = false; 4047 } 4048 } 4049 if (!UseNUMA && ForceNUMA) { 4050 UseNUMA = true; 4051 } 4052 } 4053 4054 if (MaxFDLimit) { 4055 // set the number of file descriptors to max. print out error 4056 // if getrlimit/setrlimit fails but continue regardless. 4057 struct rlimit nbr_files; 4058 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4059 if (status != 0) { 4060 if (PrintMiscellaneous && (Verbose || WizardMode)) 4061 perror("os::init_2 getrlimit failed"); 4062 } else { 4063 nbr_files.rlim_cur = nbr_files.rlim_max; 4064 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4065 if (status != 0) { 4066 if (PrintMiscellaneous && (Verbose || WizardMode)) 4067 perror("os::init_2 setrlimit failed"); 4068 } 4069 } 4070 } 4071 4072 // Initialize lock used to serialize thread creation (see os::create_thread) 4073 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4074 4075 // at-exit methods are called in the reverse order of their registration. 4076 // atexit functions are called on return from main or as a result of a 4077 // call to exit(3C). There can be only 32 of these functions registered 4078 // and atexit() does not set errno. 4079 4080 if (PerfAllowAtExitRegistration) { 4081 // only register atexit functions if PerfAllowAtExitRegistration is set. 4082 // atexit functions can be delayed until process exit time, which 4083 // can be problematic for embedded VM situations. Embedded VMs should 4084 // call DestroyJavaVM() to assure that VM resources are released. 4085 4086 // note: perfMemory_exit_helper atexit function may be removed in 4087 // the future if the appropriate cleanup code can be added to the 4088 // VM_Exit VMOperation's doit method. 4089 if (atexit(perfMemory_exit_helper) != 0) { 4090 warning("os::init2 atexit(perfMemory_exit_helper) failed"); 4091 } 4092 } 4093 4094 // initialize thread priority policy 4095 prio_init(); 4096 4097 return JNI_OK; 4098} 4099 4100// this is called at the end of vm_initialization 4101void os::init_3(void) { } 4102 4103// Mark the polling page as unreadable 4104void os::make_polling_page_unreadable(void) { 4105 if( !guard_memory((char*)_polling_page, Linux::page_size()) ) 4106 fatal("Could not disable polling page"); 4107}; 4108 4109// Mark the polling page as readable 4110void os::make_polling_page_readable(void) { 4111 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4112 fatal("Could not enable polling page"); 4113 } 4114}; 4115 4116int os::active_processor_count() { 4117 // Linux doesn't yet have a (official) notion of processor sets, 4118 // so just return the number of online processors. 4119 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4120 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4121 return online_cpus; 4122} 4123 4124bool os::distribute_processes(uint length, uint* distribution) { 4125 // Not yet implemented. 4126 return false; 4127} 4128 4129bool os::bind_to_processor(uint processor_id) { 4130 // Not yet implemented. 4131 return false; 4132} 4133 4134/// 4135 4136// Suspends the target using the signal mechanism and then grabs the PC before 4137// resuming the target. Used by the flat-profiler only 4138ExtendedPC os::get_thread_pc(Thread* thread) { 4139 // Make sure that it is called by the watcher for the VMThread 4140 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4141 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4142 4143 ExtendedPC epc; 4144 4145 OSThread* osthread = thread->osthread(); 4146 if (do_suspend(osthread)) { 4147 if (osthread->ucontext() != NULL) { 4148 epc = os::Linux::ucontext_get_pc(osthread->ucontext()); 4149 } else { 4150 // NULL context is unexpected, double-check this is the VMThread 4151 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4152 } 4153 do_resume(osthread); 4154 } 4155 // failure means pthread_kill failed for some reason - arguably this is 4156 // a fatal problem, but such problems are ignored elsewhere 4157 4158 return epc; 4159} 4160 4161int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime) 4162{ 4163 if (is_NPTL()) { 4164 return pthread_cond_timedwait(_cond, _mutex, _abstime); 4165 } else { 4166#ifndef IA64 4167 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control 4168 // word back to default 64bit precision if condvar is signaled. Java 4169 // wants 53bit precision. Save and restore current value. 4170 int fpu = get_fpu_control_word(); 4171#endif // IA64 4172 int status = pthread_cond_timedwait(_cond, _mutex, _abstime); 4173#ifndef IA64 4174 set_fpu_control_word(fpu); 4175#endif // IA64 4176 return status; 4177 } 4178} 4179 4180//////////////////////////////////////////////////////////////////////////////// 4181// debug support 4182 4183static address same_page(address x, address y) { 4184 int page_bits = -os::vm_page_size(); 4185 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits)) 4186 return x; 4187 else if (x > y) 4188 return (address)(intptr_t(y) | ~page_bits) + 1; 4189 else 4190 return (address)(intptr_t(y) & page_bits); 4191} 4192 4193bool os::find(address addr, outputStream* st) { 4194 Dl_info dlinfo; 4195 memset(&dlinfo, 0, sizeof(dlinfo)); 4196 if (dladdr(addr, &dlinfo)) { 4197 st->print(PTR_FORMAT ": ", addr); 4198 if (dlinfo.dli_sname != NULL) { 4199 st->print("%s+%#x", dlinfo.dli_sname, 4200 addr - (intptr_t)dlinfo.dli_saddr); 4201 } else if (dlinfo.dli_fname) { 4202 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 4203 } else { 4204 st->print("<absolute address>"); 4205 } 4206 if (dlinfo.dli_fname) { 4207 st->print(" in %s", dlinfo.dli_fname); 4208 } 4209 if (dlinfo.dli_fbase) { 4210 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 4211 } 4212 st->cr(); 4213 4214 if (Verbose) { 4215 // decode some bytes around the PC 4216 address begin = same_page(addr-40, addr); 4217 address end = same_page(addr+40, addr); 4218 address lowest = (address) dlinfo.dli_sname; 4219 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4220 if (begin < lowest) begin = lowest; 4221 Dl_info dlinfo2; 4222 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr 4223 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) 4224 end = (address) dlinfo2.dli_saddr; 4225 Disassembler::decode(begin, end, st); 4226 } 4227 return true; 4228 } 4229 return false; 4230} 4231 4232//////////////////////////////////////////////////////////////////////////////// 4233// misc 4234 4235// This does not do anything on Linux. This is basically a hook for being 4236// able to use structured exception handling (thread-local exception filters) 4237// on, e.g., Win32. 4238void 4239os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 4240 JavaCallArguments* args, Thread* thread) { 4241 f(value, method, args, thread); 4242} 4243 4244void os::print_statistics() { 4245} 4246 4247int os::message_box(const char* title, const char* message) { 4248 int i; 4249 fdStream err(defaultStream::error_fd()); 4250 for (i = 0; i < 78; i++) err.print_raw("="); 4251 err.cr(); 4252 err.print_raw_cr(title); 4253 for (i = 0; i < 78; i++) err.print_raw("-"); 4254 err.cr(); 4255 err.print_raw_cr(message); 4256 for (i = 0; i < 78; i++) err.print_raw("="); 4257 err.cr(); 4258 4259 char buf[16]; 4260 // Prevent process from exiting upon "read error" without consuming all CPU 4261 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4262 4263 return buf[0] == 'y' || buf[0] == 'Y'; 4264} 4265 4266int os::stat(const char *path, struct stat *sbuf) { 4267 char pathbuf[MAX_PATH]; 4268 if (strlen(path) > MAX_PATH - 1) { 4269 errno = ENAMETOOLONG; 4270 return -1; 4271 } 4272 os::native_path(strcpy(pathbuf, path)); 4273 return ::stat(pathbuf, sbuf); 4274} 4275 4276bool os::check_heap(bool force) { 4277 return true; 4278} 4279 4280int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) { 4281 return ::vsnprintf(buf, count, format, args); 4282} 4283 4284// Is a (classpath) directory empty? 4285bool os::dir_is_empty(const char* path) { 4286 DIR *dir = NULL; 4287 struct dirent *ptr; 4288 4289 dir = opendir(path); 4290 if (dir == NULL) return true; 4291 4292 /* Scan the directory */ 4293 bool result = true; 4294 char buf[sizeof(struct dirent) + MAX_PATH]; 4295 while (result && (ptr = ::readdir(dir)) != NULL) { 4296 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 4297 result = false; 4298 } 4299 } 4300 closedir(dir); 4301 return result; 4302} 4303 4304// This code originates from JDK's sysOpen and open64_w 4305// from src/solaris/hpi/src/system_md.c 4306 4307#ifndef O_DELETE 4308#define O_DELETE 0x10000 4309#endif 4310 4311// Open a file. Unlink the file immediately after open returns 4312// if the specified oflag has the O_DELETE flag set. 4313// O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c 4314 4315int os::open(const char *path, int oflag, int mode) { 4316 4317 if (strlen(path) > MAX_PATH - 1) { 4318 errno = ENAMETOOLONG; 4319 return -1; 4320 } 4321 int fd; 4322 int o_delete = (oflag & O_DELETE); 4323 oflag = oflag & ~O_DELETE; 4324 4325 fd = ::open64(path, oflag, mode); 4326 if (fd == -1) return -1; 4327 4328 //If the open succeeded, the file might still be a directory 4329 { 4330 struct stat64 buf64; 4331 int ret = ::fstat64(fd, &buf64); 4332 int st_mode = buf64.st_mode; 4333 4334 if (ret != -1) { 4335 if ((st_mode & S_IFMT) == S_IFDIR) { 4336 errno = EISDIR; 4337 ::close(fd); 4338 return -1; 4339 } 4340 } else { 4341 ::close(fd); 4342 return -1; 4343 } 4344 } 4345 4346 /* 4347 * All file descriptors that are opened in the JVM and not 4348 * specifically destined for a subprocess should have the 4349 * close-on-exec flag set. If we don't set it, then careless 3rd 4350 * party native code might fork and exec without closing all 4351 * appropriate file descriptors (e.g. as we do in closeDescriptors in 4352 * UNIXProcess.c), and this in turn might: 4353 * 4354 * - cause end-of-file to fail to be detected on some file 4355 * descriptors, resulting in mysterious hangs, or 4356 * 4357 * - might cause an fopen in the subprocess to fail on a system 4358 * suffering from bug 1085341. 4359 * 4360 * (Yes, the default setting of the close-on-exec flag is a Unix 4361 * design flaw) 4362 * 4363 * See: 4364 * 1085341: 32-bit stdio routines should support file descriptors >255 4365 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed 4366 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 4367 */ 4368#ifdef FD_CLOEXEC 4369 { 4370 int flags = ::fcntl(fd, F_GETFD); 4371 if (flags != -1) 4372 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 4373 } 4374#endif 4375 4376 if (o_delete != 0) { 4377 ::unlink(path); 4378 } 4379 return fd; 4380} 4381 4382 4383// create binary file, rewriting existing file if required 4384int os::create_binary_file(const char* path, bool rewrite_existing) { 4385 int oflags = O_WRONLY | O_CREAT; 4386 if (!rewrite_existing) { 4387 oflags |= O_EXCL; 4388 } 4389 return ::open64(path, oflags, S_IREAD | S_IWRITE); 4390} 4391 4392// return current position of file pointer 4393jlong os::current_file_offset(int fd) { 4394 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 4395} 4396 4397// move file pointer to the specified offset 4398jlong os::seek_to_file_offset(int fd, jlong offset) { 4399 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 4400} 4401 4402// This code originates from JDK's sysAvailable 4403// from src/solaris/hpi/src/native_threads/src/sys_api_td.c 4404 4405int os::available(int fd, jlong *bytes) { 4406 jlong cur, end; 4407 int mode; 4408 struct stat64 buf64; 4409 4410 if (::fstat64(fd, &buf64) >= 0) { 4411 mode = buf64.st_mode; 4412 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 4413 /* 4414 * XXX: is the following call interruptible? If so, this might 4415 * need to go through the INTERRUPT_IO() wrapper as for other 4416 * blocking, interruptible calls in this file. 4417 */ 4418 int n; 4419 if (::ioctl(fd, FIONREAD, &n) >= 0) { 4420 *bytes = n; 4421 return 1; 4422 } 4423 } 4424 } 4425 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 4426 return 0; 4427 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 4428 return 0; 4429 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 4430 return 0; 4431 } 4432 *bytes = end - cur; 4433 return 1; 4434} 4435 4436// Map a block of memory. 4437char* os::map_memory(int fd, const char* file_name, size_t file_offset, 4438 char *addr, size_t bytes, bool read_only, 4439 bool allow_exec) { 4440 int prot; 4441 int flags; 4442 4443 if (read_only) { 4444 prot = PROT_READ; 4445 flags = MAP_SHARED; 4446 } else { 4447 prot = PROT_READ | PROT_WRITE; 4448 flags = MAP_PRIVATE; 4449 } 4450 4451 if (allow_exec) { 4452 prot |= PROT_EXEC; 4453 } 4454 4455 if (addr != NULL) { 4456 flags |= MAP_FIXED; 4457 } 4458 4459 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 4460 fd, file_offset); 4461 if (mapped_address == MAP_FAILED) { 4462 return NULL; 4463 } 4464 return mapped_address; 4465} 4466 4467 4468// Remap a block of memory. 4469char* os::remap_memory(int fd, const char* file_name, size_t file_offset, 4470 char *addr, size_t bytes, bool read_only, 4471 bool allow_exec) { 4472 // same as map_memory() on this OS 4473 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 4474 allow_exec); 4475} 4476 4477 4478// Unmap a block of memory. 4479bool os::unmap_memory(char* addr, size_t bytes) { 4480 return munmap(addr, bytes) == 0; 4481} 4482 4483static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 4484 4485static clockid_t thread_cpu_clockid(Thread* thread) { 4486 pthread_t tid = thread->osthread()->pthread_id(); 4487 clockid_t clockid; 4488 4489 // Get thread clockid 4490 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 4491 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 4492 return clockid; 4493} 4494 4495// current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 4496// are used by JVM M&M and JVMTI to get user+sys or user CPU time 4497// of a thread. 4498// 4499// current_thread_cpu_time() and thread_cpu_time(Thread*) returns 4500// the fast estimate available on the platform. 4501 4502jlong os::current_thread_cpu_time() { 4503 if (os::Linux::supports_fast_thread_cpu_time()) { 4504 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4505 } else { 4506 // return user + sys since the cost is the same 4507 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 4508 } 4509} 4510 4511jlong os::thread_cpu_time(Thread* thread) { 4512 // consistent with what current_thread_cpu_time() returns 4513 if (os::Linux::supports_fast_thread_cpu_time()) { 4514 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4515 } else { 4516 return slow_thread_cpu_time(thread, true /* user + sys */); 4517 } 4518} 4519 4520jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 4521 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4522 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4523 } else { 4524 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 4525 } 4526} 4527 4528jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4529 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4530 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4531 } else { 4532 return slow_thread_cpu_time(thread, user_sys_cpu_time); 4533 } 4534} 4535 4536// 4537// -1 on error. 4538// 4539 4540static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4541 static bool proc_pid_cpu_avail = true; 4542 static bool proc_task_unchecked = true; 4543 static const char *proc_stat_path = "/proc/%d/stat"; 4544 pid_t tid = thread->osthread()->thread_id(); 4545 int i; 4546 char *s; 4547 char stat[2048]; 4548 int statlen; 4549 char proc_name[64]; 4550 int count; 4551 long sys_time, user_time; 4552 char string[64]; 4553 char cdummy; 4554 int idummy; 4555 long ldummy; 4556 FILE *fp; 4557 4558 // We first try accessing /proc/<pid>/cpu since this is faster to 4559 // process. If this file is not present (linux kernels 2.5 and above) 4560 // then we open /proc/<pid>/stat. 4561 if ( proc_pid_cpu_avail ) { 4562 sprintf(proc_name, "/proc/%d/cpu", tid); 4563 fp = fopen(proc_name, "r"); 4564 if ( fp != NULL ) { 4565 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time); 4566 fclose(fp); 4567 if ( count != 3 ) return -1; 4568 4569 if (user_sys_cpu_time) { 4570 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4571 } else { 4572 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4573 } 4574 } 4575 else proc_pid_cpu_avail = false; 4576 } 4577 4578 // The /proc/<tid>/stat aggregates per-process usage on 4579 // new Linux kernels 2.6+ where NPTL is supported. 4580 // The /proc/self/task/<tid>/stat still has the per-thread usage. 4581 // See bug 6328462. 4582 // There can be no directory /proc/self/task on kernels 2.4 with NPTL 4583 // and possibly in some other cases, so we check its availability. 4584 if (proc_task_unchecked && os::Linux::is_NPTL()) { 4585 // This is executed only once 4586 proc_task_unchecked = false; 4587 fp = fopen("/proc/self/task", "r"); 4588 if (fp != NULL) { 4589 proc_stat_path = "/proc/self/task/%d/stat"; 4590 fclose(fp); 4591 } 4592 } 4593 4594 sprintf(proc_name, proc_stat_path, tid); 4595 fp = fopen(proc_name, "r"); 4596 if ( fp == NULL ) return -1; 4597 statlen = fread(stat, 1, 2047, fp); 4598 stat[statlen] = '\0'; 4599 fclose(fp); 4600 4601 // Skip pid and the command string. Note that we could be dealing with 4602 // weird command names, e.g. user could decide to rename java launcher 4603 // to "java 1.4.2 :)", then the stat file would look like 4604 // 1234 (java 1.4.2 :)) R ... ... 4605 // We don't really need to know the command string, just find the last 4606 // occurrence of ")" and then start parsing from there. See bug 4726580. 4607 s = strrchr(stat, ')'); 4608 i = 0; 4609 if (s == NULL ) return -1; 4610 4611 // Skip blank chars 4612 do s++; while (isspace(*s)); 4613 4614 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 4615 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 4616 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 4617 &user_time, &sys_time); 4618 if ( count != 13 ) return -1; 4619 if (user_sys_cpu_time) { 4620 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4621 } else { 4622 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4623 } 4624} 4625 4626void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4627 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4628 info_ptr->may_skip_backward = false; // elapsed time not wall time 4629 info_ptr->may_skip_forward = false; // elapsed time not wall time 4630 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4631} 4632 4633void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4634 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4635 info_ptr->may_skip_backward = false; // elapsed time not wall time 4636 info_ptr->may_skip_forward = false; // elapsed time not wall time 4637 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4638} 4639 4640bool os::is_thread_cpu_time_supported() { 4641 return true; 4642} 4643 4644// System loadavg support. Returns -1 if load average cannot be obtained. 4645// Linux doesn't yet have a (official) notion of processor sets, 4646// so just return the system wide load average. 4647int os::loadavg(double loadavg[], int nelem) { 4648 return ::getloadavg(loadavg, nelem); 4649} 4650 4651void os::pause() { 4652 char filename[MAX_PATH]; 4653 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 4654 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 4655 } else { 4656 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 4657 } 4658 4659 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 4660 if (fd != -1) { 4661 struct stat buf; 4662 ::close(fd); 4663 while (::stat(filename, &buf) == 0) { 4664 (void)::poll(NULL, 0, 100); 4665 } 4666 } else { 4667 jio_fprintf(stderr, 4668 "Could not open pause file '%s', continuing immediately.\n", filename); 4669 } 4670} 4671 4672extern "C" { 4673 4674/** 4675 * NOTE: the following code is to keep the green threads code 4676 * in the libjava.so happy. Once the green threads is removed, 4677 * these code will no longer be needed. 4678 */ 4679int 4680jdk_waitpid(pid_t pid, int* status, int options) { 4681 return waitpid(pid, status, options); 4682} 4683 4684int 4685fork1() { 4686 return fork(); 4687} 4688 4689int 4690jdk_sem_init(sem_t *sem, int pshared, unsigned int value) { 4691 return sem_init(sem, pshared, value); 4692} 4693 4694int 4695jdk_sem_post(sem_t *sem) { 4696 return sem_post(sem); 4697} 4698 4699int 4700jdk_sem_wait(sem_t *sem) { 4701 return sem_wait(sem); 4702} 4703 4704int 4705jdk_pthread_sigmask(int how , const sigset_t* newmask, sigset_t* oldmask) { 4706 return pthread_sigmask(how , newmask, oldmask); 4707} 4708 4709} 4710 4711// Refer to the comments in os_solaris.cpp park-unpark. 4712// 4713// Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 4714// hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 4715// For specifics regarding the bug see GLIBC BUGID 261237 : 4716// http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 4717// Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 4718// will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 4719// is used. (The simple C test-case provided in the GLIBC bug report manifests the 4720// hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 4721// and monitorenter when we're using 1-0 locking. All those operations may result in 4722// calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 4723// of libpthread avoids the problem, but isn't practical. 4724// 4725// Possible remedies: 4726// 4727// 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 4728// This is palliative and probabilistic, however. If the thread is preempted 4729// between the call to compute_abstime() and pthread_cond_timedwait(), more 4730// than the minimum period may have passed, and the abstime may be stale (in the 4731// past) resultin in a hang. Using this technique reduces the odds of a hang 4732// but the JVM is still vulnerable, particularly on heavily loaded systems. 4733// 4734// 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 4735// of the usual flag-condvar-mutex idiom. The write side of the pipe is set 4736// NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 4737// reduces to poll()+read(). This works well, but consumes 2 FDs per extant 4738// thread. 4739// 4740// 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 4741// that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 4742// a timeout request to the chron thread and then blocking via pthread_cond_wait(). 4743// This also works well. In fact it avoids kernel-level scalability impediments 4744// on certain platforms that don't handle lots of active pthread_cond_timedwait() 4745// timers in a graceful fashion. 4746// 4747// 4. When the abstime value is in the past it appears that control returns 4748// correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 4749// Subsequent timedwait/wait calls may hang indefinitely. Given that, we 4750// can avoid the problem by reinitializing the condvar -- by cond_destroy() 4751// followed by cond_init() -- after all calls to pthread_cond_timedwait(). 4752// It may be possible to avoid reinitialization by checking the return 4753// value from pthread_cond_timedwait(). In addition to reinitializing the 4754// condvar we must establish the invariant that cond_signal() is only called 4755// within critical sections protected by the adjunct mutex. This prevents 4756// cond_signal() from "seeing" a condvar that's in the midst of being 4757// reinitialized or that is corrupt. Sadly, this invariant obviates the 4758// desirable signal-after-unlock optimization that avoids futile context switching. 4759// 4760// I'm also concerned that some versions of NTPL might allocate an auxilliary 4761// structure when a condvar is used or initialized. cond_destroy() would 4762// release the helper structure. Our reinitialize-after-timedwait fix 4763// put excessive stress on malloc/free and locks protecting the c-heap. 4764// 4765// We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 4766// It may be possible to refine (4) by checking the kernel and NTPL verisons 4767// and only enabling the work-around for vulnerable environments. 4768 4769// utility to compute the abstime argument to timedwait: 4770// millis is the relative timeout time 4771// abstime will be the absolute timeout time 4772// TODO: replace compute_abstime() with unpackTime() 4773 4774static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 4775 if (millis < 0) millis = 0; 4776 struct timeval now; 4777 int status = gettimeofday(&now, NULL); 4778 assert(status == 0, "gettimeofday"); 4779 jlong seconds = millis / 1000; 4780 millis %= 1000; 4781 if (seconds > 50000000) { // see man cond_timedwait(3T) 4782 seconds = 50000000; 4783 } 4784 abstime->tv_sec = now.tv_sec + seconds; 4785 long usec = now.tv_usec + millis * 1000; 4786 if (usec >= 1000000) { 4787 abstime->tv_sec += 1; 4788 usec -= 1000000; 4789 } 4790 abstime->tv_nsec = usec * 1000; 4791 return abstime; 4792} 4793 4794 4795// Test-and-clear _Event, always leaves _Event set to 0, returns immediately. 4796// Conceptually TryPark() should be equivalent to park(0). 4797 4798int os::PlatformEvent::TryPark() { 4799 for (;;) { 4800 const int v = _Event ; 4801 guarantee ((v == 0) || (v == 1), "invariant") ; 4802 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ; 4803 } 4804} 4805 4806void os::PlatformEvent::park() { // AKA "down()" 4807 // Invariant: Only the thread associated with the Event/PlatformEvent 4808 // may call park(). 4809 // TODO: assert that _Assoc != NULL or _Assoc == Self 4810 int v ; 4811 for (;;) { 4812 v = _Event ; 4813 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 4814 } 4815 guarantee (v >= 0, "invariant") ; 4816 if (v == 0) { 4817 // Do this the hard way by blocking ... 4818 int status = pthread_mutex_lock(_mutex); 4819 assert_status(status == 0, status, "mutex_lock"); 4820 guarantee (_nParked == 0, "invariant") ; 4821 ++ _nParked ; 4822 while (_Event < 0) { 4823 status = pthread_cond_wait(_cond, _mutex); 4824 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 4825 // Treat this the same as if the wait was interrupted 4826 if (status == ETIME) { status = EINTR; } 4827 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 4828 } 4829 -- _nParked ; 4830 4831 // In theory we could move the ST of 0 into _Event past the unlock(), 4832 // but then we'd need a MEMBAR after the ST. 4833 _Event = 0 ; 4834 status = pthread_mutex_unlock(_mutex); 4835 assert_status(status == 0, status, "mutex_unlock"); 4836 } 4837 guarantee (_Event >= 0, "invariant") ; 4838} 4839 4840int os::PlatformEvent::park(jlong millis) { 4841 guarantee (_nParked == 0, "invariant") ; 4842 4843 int v ; 4844 for (;;) { 4845 v = _Event ; 4846 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 4847 } 4848 guarantee (v >= 0, "invariant") ; 4849 if (v != 0) return OS_OK ; 4850 4851 // We do this the hard way, by blocking the thread. 4852 // Consider enforcing a minimum timeout value. 4853 struct timespec abst; 4854 compute_abstime(&abst, millis); 4855 4856 int ret = OS_TIMEOUT; 4857 int status = pthread_mutex_lock(_mutex); 4858 assert_status(status == 0, status, "mutex_lock"); 4859 guarantee (_nParked == 0, "invariant") ; 4860 ++_nParked ; 4861 4862 // Object.wait(timo) will return because of 4863 // (a) notification 4864 // (b) timeout 4865 // (c) thread.interrupt 4866 // 4867 // Thread.interrupt and object.notify{All} both call Event::set. 4868 // That is, we treat thread.interrupt as a special case of notification. 4869 // The underlying Solaris implementation, cond_timedwait, admits 4870 // spurious/premature wakeups, but the JLS/JVM spec prevents the 4871 // JVM from making those visible to Java code. As such, we must 4872 // filter out spurious wakeups. We assume all ETIME returns are valid. 4873 // 4874 // TODO: properly differentiate simultaneous notify+interrupt. 4875 // In that case, we should propagate the notify to another waiter. 4876 4877 while (_Event < 0) { 4878 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst); 4879 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 4880 pthread_cond_destroy (_cond); 4881 pthread_cond_init (_cond, NULL) ; 4882 } 4883 assert_status(status == 0 || status == EINTR || 4884 status == ETIME || status == ETIMEDOUT, 4885 status, "cond_timedwait"); 4886 if (!FilterSpuriousWakeups) break ; // previous semantics 4887 if (status == ETIME || status == ETIMEDOUT) break ; 4888 // We consume and ignore EINTR and spurious wakeups. 4889 } 4890 --_nParked ; 4891 if (_Event >= 0) { 4892 ret = OS_OK; 4893 } 4894 _Event = 0 ; 4895 status = pthread_mutex_unlock(_mutex); 4896 assert_status(status == 0, status, "mutex_unlock"); 4897 assert (_nParked == 0, "invariant") ; 4898 return ret; 4899} 4900 4901void os::PlatformEvent::unpark() { 4902 int v, AnyWaiters ; 4903 for (;;) { 4904 v = _Event ; 4905 if (v > 0) { 4906 // The LD of _Event could have reordered or be satisfied 4907 // by a read-aside from this processor's write buffer. 4908 // To avoid problems execute a barrier and then 4909 // ratify the value. 4910 OrderAccess::fence() ; 4911 if (_Event == v) return ; 4912 continue ; 4913 } 4914 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ; 4915 } 4916 if (v < 0) { 4917 // Wait for the thread associated with the event to vacate 4918 int status = pthread_mutex_lock(_mutex); 4919 assert_status(status == 0, status, "mutex_lock"); 4920 AnyWaiters = _nParked ; 4921 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ; 4922 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 4923 AnyWaiters = 0 ; 4924 pthread_cond_signal (_cond); 4925 } 4926 status = pthread_mutex_unlock(_mutex); 4927 assert_status(status == 0, status, "mutex_unlock"); 4928 if (AnyWaiters != 0) { 4929 status = pthread_cond_signal(_cond); 4930 assert_status(status == 0, status, "cond_signal"); 4931 } 4932 } 4933 4934 // Note that we signal() _after dropping the lock for "immortal" Events. 4935 // This is safe and avoids a common class of futile wakeups. In rare 4936 // circumstances this can cause a thread to return prematurely from 4937 // cond_{timed}wait() but the spurious wakeup is benign and the victim will 4938 // simply re-test the condition and re-park itself. 4939} 4940 4941 4942// JSR166 4943// ------------------------------------------------------- 4944 4945/* 4946 * The solaris and linux implementations of park/unpark are fairly 4947 * conservative for now, but can be improved. They currently use a 4948 * mutex/condvar pair, plus a a count. 4949 * Park decrements count if > 0, else does a condvar wait. Unpark 4950 * sets count to 1 and signals condvar. Only one thread ever waits 4951 * on the condvar. Contention seen when trying to park implies that someone 4952 * is unparking you, so don't wait. And spurious returns are fine, so there 4953 * is no need to track notifications. 4954 */ 4955 4956 4957#define NANOSECS_PER_SEC 1000000000 4958#define NANOSECS_PER_MILLISEC 1000000 4959#define MAX_SECS 100000000 4960/* 4961 * This code is common to linux and solaris and will be moved to a 4962 * common place in dolphin. 4963 * 4964 * The passed in time value is either a relative time in nanoseconds 4965 * or an absolute time in milliseconds. Either way it has to be unpacked 4966 * into suitable seconds and nanoseconds components and stored in the 4967 * given timespec structure. 4968 * Given time is a 64-bit value and the time_t used in the timespec is only 4969 * a signed-32-bit value (except on 64-bit Linux) we have to watch for 4970 * overflow if times way in the future are given. Further on Solaris versions 4971 * prior to 10 there is a restriction (see cond_timedwait) that the specified 4972 * number of seconds, in abstime, is less than current_time + 100,000,000. 4973 * As it will be 28 years before "now + 100000000" will overflow we can 4974 * ignore overflow and just impose a hard-limit on seconds using the value 4975 * of "now + 100,000,000". This places a limit on the timeout of about 3.17 4976 * years from "now". 4977 */ 4978 4979static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 4980 assert (time > 0, "convertTime"); 4981 4982 struct timeval now; 4983 int status = gettimeofday(&now, NULL); 4984 assert(status == 0, "gettimeofday"); 4985 4986 time_t max_secs = now.tv_sec + MAX_SECS; 4987 4988 if (isAbsolute) { 4989 jlong secs = time / 1000; 4990 if (secs > max_secs) { 4991 absTime->tv_sec = max_secs; 4992 } 4993 else { 4994 absTime->tv_sec = secs; 4995 } 4996 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 4997 } 4998 else { 4999 jlong secs = time / NANOSECS_PER_SEC; 5000 if (secs >= MAX_SECS) { 5001 absTime->tv_sec = max_secs; 5002 absTime->tv_nsec = 0; 5003 } 5004 else { 5005 absTime->tv_sec = now.tv_sec + secs; 5006 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5007 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5008 absTime->tv_nsec -= NANOSECS_PER_SEC; 5009 ++absTime->tv_sec; // note: this must be <= max_secs 5010 } 5011 } 5012 } 5013 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5014 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5015 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5016 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5017} 5018 5019void Parker::park(bool isAbsolute, jlong time) { 5020 // Optional fast-path check: 5021 // Return immediately if a permit is available. 5022 if (_counter > 0) { 5023 _counter = 0 ; 5024 OrderAccess::fence(); 5025 return ; 5026 } 5027 5028 Thread* thread = Thread::current(); 5029 assert(thread->is_Java_thread(), "Must be JavaThread"); 5030 JavaThread *jt = (JavaThread *)thread; 5031 5032 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5033 // Check interrupt before trying to wait 5034 if (Thread::is_interrupted(thread, false)) { 5035 return; 5036 } 5037 5038 // Next, demultiplex/decode time arguments 5039 timespec absTime; 5040 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all 5041 return; 5042 } 5043 if (time > 0) { 5044 unpackTime(&absTime, isAbsolute, time); 5045 } 5046 5047 5048 // Enter safepoint region 5049 // Beware of deadlocks such as 6317397. 5050 // The per-thread Parker:: mutex is a classic leaf-lock. 5051 // In particular a thread must never block on the Threads_lock while 5052 // holding the Parker:: mutex. If safepoints are pending both the 5053 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5054 ThreadBlockInVM tbivm(jt); 5055 5056 // Don't wait if cannot get lock since interference arises from 5057 // unblocking. Also. check interrupt before trying wait 5058 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5059 return; 5060 } 5061 5062 int status ; 5063 if (_counter > 0) { // no wait needed 5064 _counter = 0; 5065 status = pthread_mutex_unlock(_mutex); 5066 assert (status == 0, "invariant") ; 5067 OrderAccess::fence(); 5068 return; 5069 } 5070 5071#ifdef ASSERT 5072 // Don't catch signals while blocked; let the running threads have the signals. 5073 // (This allows a debugger to break into the running thread.) 5074 sigset_t oldsigs; 5075 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5076 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5077#endif 5078 5079 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5080 jt->set_suspend_equivalent(); 5081 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5082 5083 if (time == 0) { 5084 status = pthread_cond_wait (_cond, _mutex) ; 5085 } else { 5086 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ; 5087 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5088 pthread_cond_destroy (_cond) ; 5089 pthread_cond_init (_cond, NULL); 5090 } 5091 } 5092 assert_status(status == 0 || status == EINTR || 5093 status == ETIME || status == ETIMEDOUT, 5094 status, "cond_timedwait"); 5095 5096#ifdef ASSERT 5097 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5098#endif 5099 5100 _counter = 0 ; 5101 status = pthread_mutex_unlock(_mutex) ; 5102 assert_status(status == 0, status, "invariant") ; 5103 // If externally suspended while waiting, re-suspend 5104 if (jt->handle_special_suspend_equivalent_condition()) { 5105 jt->java_suspend_self(); 5106 } 5107 5108 OrderAccess::fence(); 5109} 5110 5111void Parker::unpark() { 5112 int s, status ; 5113 status = pthread_mutex_lock(_mutex); 5114 assert (status == 0, "invariant") ; 5115 s = _counter; 5116 _counter = 1; 5117 if (s < 1) { 5118 if (WorkAroundNPTLTimedWaitHang) { 5119 status = pthread_cond_signal (_cond) ; 5120 assert (status == 0, "invariant") ; 5121 status = pthread_mutex_unlock(_mutex); 5122 assert (status == 0, "invariant") ; 5123 } else { 5124 status = pthread_mutex_unlock(_mutex); 5125 assert (status == 0, "invariant") ; 5126 status = pthread_cond_signal (_cond) ; 5127 assert (status == 0, "invariant") ; 5128 } 5129 } else { 5130 pthread_mutex_unlock(_mutex); 5131 assert (status == 0, "invariant") ; 5132 } 5133} 5134 5135 5136extern char** environ; 5137 5138#ifndef __NR_fork 5139#define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) 5140#endif 5141 5142#ifndef __NR_execve 5143#define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) 5144#endif 5145 5146// Run the specified command in a separate process. Return its exit value, 5147// or -1 on failure (e.g. can't fork a new process). 5148// Unlike system(), this function can be called from signal handler. It 5149// doesn't block SIGINT et al. 5150int os::fork_and_exec(char* cmd) { 5151 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5152 5153 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run 5154 // pthread_atfork handlers and reset pthread library. All we need is a 5155 // separate process to execve. Make a direct syscall to fork process. 5156 // On IA64 there's no fork syscall, we have to use fork() and hope for 5157 // the best... 5158 pid_t pid = NOT_IA64(syscall(__NR_fork);) 5159 IA64_ONLY(fork();) 5160 5161 if (pid < 0) { 5162 // fork failed 5163 return -1; 5164 5165 } else if (pid == 0) { 5166 // child process 5167 5168 // execve() in LinuxThreads will call pthread_kill_other_threads_np() 5169 // first to kill every thread on the thread list. Because this list is 5170 // not reset by fork() (see notes above), execve() will instead kill 5171 // every thread in the parent process. We know this is the only thread 5172 // in the new process, so make a system call directly. 5173 // IA64 should use normal execve() from glibc to match the glibc fork() 5174 // above. 5175 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);) 5176 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);) 5177 5178 // execve failed 5179 _exit(-1); 5180 5181 } else { 5182 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5183 // care about the actual exit code, for now. 5184 5185 int status; 5186 5187 // Wait for the child process to exit. This returns immediately if 5188 // the child has already exited. */ 5189 while (waitpid(pid, &status, 0) < 0) { 5190 switch (errno) { 5191 case ECHILD: return 0; 5192 case EINTR: break; 5193 default: return -1; 5194 } 5195 } 5196 5197 if (WIFEXITED(status)) { 5198 // The child exited normally; get its exit code. 5199 return WEXITSTATUS(status); 5200 } else if (WIFSIGNALED(status)) { 5201 // The child exited because of a signal 5202 // The best value to return is 0x80 + signal number, 5203 // because that is what all Unix shells do, and because 5204 // it allows callers to distinguish between process exit and 5205 // process death by signal. 5206 return 0x80 + WTERMSIG(status); 5207 } else { 5208 // Unknown exit code; pass it through 5209 return status; 5210 } 5211 } 5212} 5213 5214// is_headless_jre() 5215// 5216// Test for the existence of libmawt in motif21 or xawt directories 5217// in order to report if we are running in a headless jre 5218// 5219bool os::is_headless_jre() { 5220 struct stat statbuf; 5221 char buf[MAXPATHLEN]; 5222 char libmawtpath[MAXPATHLEN]; 5223 const char *xawtstr = "/xawt/libmawt.so"; 5224 const char *motifstr = "/motif21/libmawt.so"; 5225 char *p; 5226 5227 // Get path to libjvm.so 5228 os::jvm_path(buf, sizeof(buf)); 5229 5230 // Get rid of libjvm.so 5231 p = strrchr(buf, '/'); 5232 if (p == NULL) return false; 5233 else *p = '\0'; 5234 5235 // Get rid of client or server 5236 p = strrchr(buf, '/'); 5237 if (p == NULL) return false; 5238 else *p = '\0'; 5239 5240 // check xawt/libmawt.so 5241 strcpy(libmawtpath, buf); 5242 strcat(libmawtpath, xawtstr); 5243 if (::stat(libmawtpath, &statbuf) == 0) return false; 5244 5245 // check motif21/libmawt.so 5246 strcpy(libmawtpath, buf); 5247 strcat(libmawtpath, motifstr); 5248 if (::stat(libmawtpath, &statbuf) == 0) return false; 5249 5250 return true; 5251} 5252 5253