os_linux.cpp revision 2387:7f3faf7159fd
138032Speter/* 238032Speter * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved. 3261363Sgshapiro * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 464562Sgshapiro * 538032Speter * This code is free software; you can redistribute it and/or modify it 638032Speter * under the terms of the GNU General Public License version 2 only, as 738032Speter * published by the Free Software Foundation. 838032Speter * 938032Speter * This code is distributed in the hope that it will be useful, but WITHOUT 1038032Speter * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 1138032Speter * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 1238032Speter * version 2 for more details (a copy is included in the LICENSE file that 13266692Sgshapiro * accompanied this code). 1438032Speter * 1538032Speter * You should have received a copy of the GNU General Public License version 1638032Speter * 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 TARGET_ARCH_arm 80# include "assembler_arm.inline.hpp" 81# include "nativeInst_arm.hpp" 82#endif 83#ifdef TARGET_ARCH_ppc 84# include "assembler_ppc.inline.hpp" 85# include "nativeInst_ppc.hpp" 86#endif 87#ifdef COMPILER1 88#include "c1/c1_Runtime1.hpp" 89#endif 90#ifdef COMPILER2 91#include "opto/runtime.hpp" 92#endif 93 94// put OS-includes here 95# include <sys/types.h> 96# include <sys/mman.h> 97# include <sys/stat.h> 98# include <sys/select.h> 99# include <pthread.h> 100# include <signal.h> 101# include <errno.h> 102# include <dlfcn.h> 103# include <stdio.h> 104# include <unistd.h> 105# include <sys/resource.h> 106# include <pthread.h> 107# include <sys/stat.h> 108# include <sys/time.h> 109# include <sys/times.h> 110# include <sys/utsname.h> 111# include <sys/socket.h> 112# include <sys/wait.h> 113# include <pwd.h> 114# include <poll.h> 115# include <semaphore.h> 116# include <fcntl.h> 117# include <string.h> 118# include <syscall.h> 119# include <sys/sysinfo.h> 120# include <gnu/libc-version.h> 121# include <sys/ipc.h> 122# include <sys/shm.h> 123# include <link.h> 124# include <stdint.h> 125# include <inttypes.h> 126# include <sys/ioctl.h> 127 128#define MAX_PATH (2 * K) 129 130// for timer info max values which include all bits 131#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 132#define SEC_IN_NANOSECS 1000000000LL 133 134#define LARGEPAGES_BIT (1 << 6) 135//////////////////////////////////////////////////////////////////////////////// 136// global variables 137julong os::Linux::_physical_memory = 0; 138 139address os::Linux::_initial_thread_stack_bottom = NULL; 140uintptr_t os::Linux::_initial_thread_stack_size = 0; 141 142int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 143int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 144Mutex* os::Linux::_createThread_lock = NULL; 145pthread_t os::Linux::_main_thread; 146int os::Linux::_page_size = -1; 147bool os::Linux::_is_floating_stack = false; 148bool os::Linux::_is_NPTL = false; 149bool os::Linux::_supports_fast_thread_cpu_time = false; 150const char * os::Linux::_glibc_version = NULL; 151const char * os::Linux::_libpthread_version = NULL; 152 153static jlong initial_time_count=0; 154 155static int clock_tics_per_sec = 100; 156 157// For diagnostics to print a message once. see run_periodic_checks 158static sigset_t check_signal_done; 159static bool check_signals = true;; 160 161static pid_t _initial_pid = 0; 162 163/* Signal number used to suspend/resume a thread */ 164 165/* do not use any signal number less than SIGSEGV, see 4355769 */ 166static int SR_signum = SIGUSR2; 167sigset_t SR_sigset; 168 169/* Used to protect dlsym() calls */ 170static pthread_mutex_t dl_mutex; 171 172//////////////////////////////////////////////////////////////////////////////// 173// utility functions 174 175static int SR_initialize(); 176static int SR_finalize(); 177 178julong os::available_memory() { 179 return Linux::available_memory(); 180} 181 182julong os::Linux::available_memory() { 183 // values in struct sysinfo are "unsigned long" 184 struct sysinfo si; 185 sysinfo(&si); 186 187 return (julong)si.freeram * si.mem_unit; 188} 189 190julong os::physical_memory() { 191 return Linux::physical_memory(); 192} 193 194julong os::allocatable_physical_memory(julong size) { 195#ifdef _LP64 196 return size; 197#else 198 julong result = MIN2(size, (julong)3800*M); 199 if (!is_allocatable(result)) { 200 // See comments under solaris for alignment considerations 201 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size(); 202 result = MIN2(size, reasonable_size); 203 } 204 return result; 205#endif // _LP64 206} 207 208//////////////////////////////////////////////////////////////////////////////// 209// environment support 210 211bool os::getenv(const char* name, char* buf, int len) { 212 const char* val = ::getenv(name); 213 if (val != NULL && strlen(val) < (size_t)len) { 214 strcpy(buf, val); 215 return true; 216 } 217 if (len > 0) buf[0] = 0; // return a null string 218 return false; 219} 220 221 222// Return true if user is running as root. 223 224bool os::have_special_privileges() { 225 static bool init = false; 226 static bool privileges = false; 227 if (!init) { 228 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 229 init = true; 230 } 231 return privileges; 232} 233 234 235#ifndef SYS_gettid 236// i386: 224, ia64: 1105, amd64: 186, sparc 143 237#ifdef __ia64__ 238#define SYS_gettid 1105 239#elif __i386__ 240#define SYS_gettid 224 241#elif __amd64__ 242#define SYS_gettid 186 243#elif __sparc__ 244#define SYS_gettid 143 245#else 246#error define gettid for the arch 247#endif 248#endif 249 250// Cpu architecture string 251#if defined(ZERO) 252static char cpu_arch[] = ZERO_LIBARCH; 253#elif defined(IA64) 254static char cpu_arch[] = "ia64"; 255#elif defined(IA32) 256static char cpu_arch[] = "i386"; 257#elif defined(AMD64) 258static char cpu_arch[] = "amd64"; 259#elif defined(ARM) 260static char cpu_arch[] = "arm"; 261#elif defined(PPC) 262static char cpu_arch[] = "ppc"; 263#elif defined(SPARC) 264# ifdef _LP64 265static char cpu_arch[] = "sparcv9"; 266# else 267static char cpu_arch[] = "sparc"; 268# endif 269#else 270#error Add appropriate cpu_arch setting 271#endif 272 273 274// pid_t gettid() 275// 276// Returns the kernel thread id of the currently running thread. Kernel 277// thread id is used to access /proc. 278// 279// (Note that getpid() on LinuxThreads returns kernel thread id too; but 280// on NPTL, it returns the same pid for all threads, as required by POSIX.) 281// 282pid_t os::Linux::gettid() { 283 int rslt = syscall(SYS_gettid); 284 if (rslt == -1) { 285 // old kernel, no NPTL support 286 return getpid(); 287 } else { 288 return (pid_t)rslt; 289 } 290} 291 292// Most versions of linux have a bug where the number of processors are 293// determined by looking at the /proc file system. In a chroot environment, 294// the system call returns 1. This causes the VM to act as if it is 295// a single processor and elide locking (see is_MP() call). 296static bool unsafe_chroot_detected = false; 297static const char *unstable_chroot_error = "/proc file system not found.\n" 298 "Java may be unstable running multithreaded in a chroot " 299 "environment on Linux when /proc filesystem is not mounted."; 300 301void os::Linux::initialize_system_info() { 302 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 303 if (processor_count() == 1) { 304 pid_t pid = os::Linux::gettid(); 305 char fname[32]; 306 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 307 FILE *fp = fopen(fname, "r"); 308 if (fp == NULL) { 309 unsafe_chroot_detected = true; 310 } else { 311 fclose(fp); 312 } 313 } 314 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 315 assert(processor_count() > 0, "linux error"); 316} 317 318void os::init_system_properties_values() { 319// char arch[12]; 320// sysinfo(SI_ARCHITECTURE, arch, sizeof(arch)); 321 322 // The next steps are taken in the product version: 323 // 324 // Obtain the JAVA_HOME value from the location of libjvm[_g].so. 325 // This library should be located at: 326 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so. 327 // 328 // If "/jre/lib/" appears at the right place in the path, then we 329 // assume libjvm[_g].so is installed in a JDK and we use this path. 330 // 331 // Otherwise exit with message: "Could not create the Java virtual machine." 332 // 333 // The following extra steps are taken in the debugging version: 334 // 335 // If "/jre/lib/" does NOT appear at the right place in the path 336 // instead of exit check for $JAVA_HOME environment variable. 337 // 338 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 339 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so 340 // it looks like libjvm[_g].so is installed there 341 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so. 342 // 343 // Otherwise exit. 344 // 345 // Important note: if the location of libjvm.so changes this 346 // code needs to be changed accordingly. 347 348 // The next few definitions allow the code to be verbatim: 349#define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n)) 350#define getenv(n) ::getenv(n) 351 352/* 353 * See ld(1): 354 * The linker uses the following search paths to locate required 355 * shared libraries: 356 * 1: ... 357 * ... 358 * 7: The default directories, normally /lib and /usr/lib. 359 */ 360#if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 361#define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 362#else 363#define DEFAULT_LIBPATH "/lib:/usr/lib" 364#endif 365 366#define EXTENSIONS_DIR "/lib/ext" 367#define ENDORSED_DIR "/lib/endorsed" 368#define REG_DIR "/usr/java/packages" 369 370 { 371 /* sysclasspath, java_home, dll_dir */ 372 { 373 char *home_path; 374 char *dll_path; 375 char *pslash; 376 char buf[MAXPATHLEN]; 377 os::jvm_path(buf, sizeof(buf)); 378 379 // Found the full path to libjvm.so. 380 // Now cut the path to <java_home>/jre if we can. 381 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */ 382 pslash = strrchr(buf, '/'); 383 if (pslash != NULL) 384 *pslash = '\0'; /* get rid of /{client|server|hotspot} */ 385 dll_path = malloc(strlen(buf) + 1); 386 if (dll_path == NULL) 387 return; 388 strcpy(dll_path, buf); 389 Arguments::set_dll_dir(dll_path); 390 391 if (pslash != NULL) { 392 pslash = strrchr(buf, '/'); 393 if (pslash != NULL) { 394 *pslash = '\0'; /* get rid of /<arch> */ 395 pslash = strrchr(buf, '/'); 396 if (pslash != NULL) 397 *pslash = '\0'; /* get rid of /lib */ 398 } 399 } 400 401 home_path = malloc(strlen(buf) + 1); 402 if (home_path == NULL) 403 return; 404 strcpy(home_path, buf); 405 Arguments::set_java_home(home_path); 406 407 if (!set_boot_path('/', ':')) 408 return; 409 } 410 411 /* 412 * Where to look for native libraries 413 * 414 * Note: Due to a legacy implementation, most of the library path 415 * is set in the launcher. This was to accomodate linking restrictions 416 * on legacy Linux implementations (which are no longer supported). 417 * Eventually, all the library path setting will be done here. 418 * 419 * However, to prevent the proliferation of improperly built native 420 * libraries, the new path component /usr/java/packages is added here. 421 * Eventually, all the library path setting will be done here. 422 */ 423 { 424 char *ld_library_path; 425 426 /* 427 * Construct the invariant part of ld_library_path. Note that the 428 * space for the colon and the trailing null are provided by the 429 * nulls included by the sizeof operator (so actually we allocate 430 * a byte more than necessary). 431 */ 432 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") + 433 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH)); 434 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch); 435 436 /* 437 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It 438 * should always exist (until the legacy problem cited above is 439 * addressed). 440 */ 441 char *v = getenv("LD_LIBRARY_PATH"); 442 if (v != NULL) { 443 char *t = ld_library_path; 444 /* That's +1 for the colon and +1 for the trailing '\0' */ 445 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1); 446 sprintf(ld_library_path, "%s:%s", v, t); 447 } 448 Arguments::set_library_path(ld_library_path); 449 } 450 451 /* 452 * Extensions directories. 453 * 454 * Note that the space for the colon and the trailing null are provided 455 * by the nulls included by the sizeof operator (so actually one byte more 456 * than necessary is allocated). 457 */ 458 { 459 char *buf = malloc(strlen(Arguments::get_java_home()) + 460 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR)); 461 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR, 462 Arguments::get_java_home()); 463 Arguments::set_ext_dirs(buf); 464 } 465 466 /* Endorsed standards default directory. */ 467 { 468 char * buf; 469 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR)); 470 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home()); 471 Arguments::set_endorsed_dirs(buf); 472 } 473 } 474 475#undef malloc 476#undef getenv 477#undef EXTENSIONS_DIR 478#undef ENDORSED_DIR 479 480 // Done 481 return; 482} 483 484//////////////////////////////////////////////////////////////////////////////// 485// breakpoint support 486 487void os::breakpoint() { 488 BREAKPOINT; 489} 490 491extern "C" void breakpoint() { 492 // use debugger to set breakpoint here 493} 494 495//////////////////////////////////////////////////////////////////////////////// 496// signal support 497 498debug_only(static bool signal_sets_initialized = false); 499static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 500 501bool os::Linux::is_sig_ignored(int sig) { 502 struct sigaction oact; 503 sigaction(sig, (struct sigaction*)NULL, &oact); 504 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 505 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 506 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) 507 return true; 508 else 509 return false; 510} 511 512void os::Linux::signal_sets_init() { 513 // Should also have an assertion stating we are still single-threaded. 514 assert(!signal_sets_initialized, "Already initialized"); 515 // Fill in signals that are necessarily unblocked for all threads in 516 // the VM. Currently, we unblock the following signals: 517 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 518 // by -Xrs (=ReduceSignalUsage)); 519 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 520 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 521 // the dispositions or masks wrt these signals. 522 // Programs embedding the VM that want to use the above signals for their 523 // own purposes must, at this time, use the "-Xrs" option to prevent 524 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 525 // (See bug 4345157, and other related bugs). 526 // In reality, though, unblocking these signals is really a nop, since 527 // these signals are not blocked by default. 528 sigemptyset(&unblocked_sigs); 529 sigemptyset(&allowdebug_blocked_sigs); 530 sigaddset(&unblocked_sigs, SIGILL); 531 sigaddset(&unblocked_sigs, SIGSEGV); 532 sigaddset(&unblocked_sigs, SIGBUS); 533 sigaddset(&unblocked_sigs, SIGFPE); 534 sigaddset(&unblocked_sigs, SR_signum); 535 536 if (!ReduceSignalUsage) { 537 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 538 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 539 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 540 } 541 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 542 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 543 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 544 } 545 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 546 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 547 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 548 } 549 } 550 // Fill in signals that are blocked by all but the VM thread. 551 sigemptyset(&vm_sigs); 552 if (!ReduceSignalUsage) 553 sigaddset(&vm_sigs, BREAK_SIGNAL); 554 debug_only(signal_sets_initialized = true); 555 556} 557 558// These are signals that are unblocked while a thread is running Java. 559// (For some reason, they get blocked by default.) 560sigset_t* os::Linux::unblocked_signals() { 561 assert(signal_sets_initialized, "Not initialized"); 562 return &unblocked_sigs; 563} 564 565// These are the signals that are blocked while a (non-VM) thread is 566// running Java. Only the VM thread handles these signals. 567sigset_t* os::Linux::vm_signals() { 568 assert(signal_sets_initialized, "Not initialized"); 569 return &vm_sigs; 570} 571 572// These are signals that are blocked during cond_wait to allow debugger in 573sigset_t* os::Linux::allowdebug_blocked_signals() { 574 assert(signal_sets_initialized, "Not initialized"); 575 return &allowdebug_blocked_sigs; 576} 577 578void os::Linux::hotspot_sigmask(Thread* thread) { 579 580 //Save caller's signal mask before setting VM signal mask 581 sigset_t caller_sigmask; 582 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 583 584 OSThread* osthread = thread->osthread(); 585 osthread->set_caller_sigmask(caller_sigmask); 586 587 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 588 589 if (!ReduceSignalUsage) { 590 if (thread->is_VM_thread()) { 591 // Only the VM thread handles BREAK_SIGNAL ... 592 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 593 } else { 594 // ... all other threads block BREAK_SIGNAL 595 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 596 } 597 } 598} 599 600////////////////////////////////////////////////////////////////////////////// 601// detecting pthread library 602 603void os::Linux::libpthread_init() { 604 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION 605 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a 606 // generic name for earlier versions. 607 // Define macros here so we can build HotSpot on old systems. 608# ifndef _CS_GNU_LIBC_VERSION 609# define _CS_GNU_LIBC_VERSION 2 610# endif 611# ifndef _CS_GNU_LIBPTHREAD_VERSION 612# define _CS_GNU_LIBPTHREAD_VERSION 3 613# endif 614 615 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 616 if (n > 0) { 617 char *str = (char *)malloc(n); 618 confstr(_CS_GNU_LIBC_VERSION, str, n); 619 os::Linux::set_glibc_version(str); 620 } else { 621 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version() 622 static char _gnu_libc_version[32]; 623 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version), 624 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release()); 625 os::Linux::set_glibc_version(_gnu_libc_version); 626 } 627 628 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 629 if (n > 0) { 630 char *str = (char *)malloc(n); 631 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 632 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells 633 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this 634 // is the case. LinuxThreads has a hard limit on max number of threads. 635 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value. 636 // On the other hand, NPTL does not have such a limit, sysconf() 637 // will return -1 and errno is not changed. Check if it is really NPTL. 638 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 && 639 strstr(str, "NPTL") && 640 sysconf(_SC_THREAD_THREADS_MAX) > 0) { 641 free(str); 642 os::Linux::set_libpthread_version("linuxthreads"); 643 } else { 644 os::Linux::set_libpthread_version(str); 645 } 646 } else { 647 // glibc before 2.3.2 only has LinuxThreads. 648 os::Linux::set_libpthread_version("linuxthreads"); 649 } 650 651 if (strstr(libpthread_version(), "NPTL")) { 652 os::Linux::set_is_NPTL(); 653 } else { 654 os::Linux::set_is_LinuxThreads(); 655 } 656 657 // LinuxThreads have two flavors: floating-stack mode, which allows variable 658 // stack size; and fixed-stack mode. NPTL is always floating-stack. 659 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) { 660 os::Linux::set_is_floating_stack(); 661 } 662} 663 664///////////////////////////////////////////////////////////////////////////// 665// thread stack 666 667// Force Linux kernel to expand current thread stack. If "bottom" is close 668// to the stack guard, caller should block all signals. 669// 670// MAP_GROWSDOWN: 671// A special mmap() flag that is used to implement thread stacks. It tells 672// kernel that the memory region should extend downwards when needed. This 673// allows early versions of LinuxThreads to only mmap the first few pages 674// when creating a new thread. Linux kernel will automatically expand thread 675// stack as needed (on page faults). 676// 677// However, because the memory region of a MAP_GROWSDOWN stack can grow on 678// demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 679// region, it's hard to tell if the fault is due to a legitimate stack 680// access or because of reading/writing non-exist memory (e.g. buffer 681// overrun). As a rule, if the fault happens below current stack pointer, 682// Linux kernel does not expand stack, instead a SIGSEGV is sent to the 683// application (see Linux kernel fault.c). 684// 685// This Linux feature can cause SIGSEGV when VM bangs thread stack for 686// stack overflow detection. 687// 688// Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 689// not use this flag. However, the stack of initial thread is not created 690// by pthread, it is still MAP_GROWSDOWN. Also it's possible (though 691// unlikely) that user code can create a thread with MAP_GROWSDOWN stack 692// and then attach the thread to JVM. 693// 694// To get around the problem and allow stack banging on Linux, we need to 695// manually expand thread stack after receiving the SIGSEGV. 696// 697// There are two ways to expand thread stack to address "bottom", we used 698// both of them in JVM before 1.5: 699// 1. adjust stack pointer first so that it is below "bottom", and then 700// touch "bottom" 701// 2. mmap() the page in question 702// 703// Now alternate signal stack is gone, it's harder to use 2. For instance, 704// if current sp is already near the lower end of page 101, and we need to 705// call mmap() to map page 100, it is possible that part of the mmap() frame 706// will be placed in page 100. When page 100 is mapped, it is zero-filled. 707// That will destroy the mmap() frame and cause VM to crash. 708// 709// The following code works by adjusting sp first, then accessing the "bottom" 710// page to force a page fault. Linux kernel will then automatically expand the 711// stack mapping. 712// 713// _expand_stack_to() assumes its frame size is less than page size, which 714// should always be true if the function is not inlined. 715 716#if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 717#define NOINLINE 718#else 719#define NOINLINE __attribute__ ((noinline)) 720#endif 721 722static void _expand_stack_to(address bottom) NOINLINE; 723 724static void _expand_stack_to(address bottom) { 725 address sp; 726 size_t size; 727 volatile char *p; 728 729 // Adjust bottom to point to the largest address within the same page, it 730 // gives us a one-page buffer if alloca() allocates slightly more memory. 731 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 732 bottom += os::Linux::page_size() - 1; 733 734 // sp might be slightly above current stack pointer; if that's the case, we 735 // will alloca() a little more space than necessary, which is OK. Don't use 736 // os::current_stack_pointer(), as its result can be slightly below current 737 // stack pointer, causing us to not alloca enough to reach "bottom". 738 sp = (address)&sp; 739 740 if (sp > bottom) { 741 size = sp - bottom; 742 p = (volatile char *)alloca(size); 743 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 744 p[0] = '\0'; 745 } 746} 747 748bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 749 assert(t!=NULL, "just checking"); 750 assert(t->osthread()->expanding_stack(), "expand should be set"); 751 assert(t->stack_base() != NULL, "stack_base was not initialized"); 752 753 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 754 sigset_t mask_all, old_sigset; 755 sigfillset(&mask_all); 756 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 757 _expand_stack_to(addr); 758 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 759 return true; 760 } 761 return false; 762} 763 764////////////////////////////////////////////////////////////////////////////// 765// create new thread 766 767static address highest_vm_reserved_address(); 768 769// check if it's safe to start a new thread 770static bool _thread_safety_check(Thread* thread) { 771 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) { 772 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat) 773 // Heap is mmap'ed at lower end of memory space. Thread stacks are 774 // allocated (MAP_FIXED) from high address space. Every thread stack 775 // occupies a fixed size slot (usually 2Mbytes, but user can change 776 // it to other values if they rebuild LinuxThreads). 777 // 778 // Problem with MAP_FIXED is that mmap() can still succeed even part of 779 // the memory region has already been mmap'ed. That means if we have too 780 // many threads and/or very large heap, eventually thread stack will 781 // collide with heap. 782 // 783 // Here we try to prevent heap/stack collision by comparing current 784 // stack bottom with the highest address that has been mmap'ed by JVM 785 // plus a safety margin for memory maps created by native code. 786 // 787 // This feature can be disabled by setting ThreadSafetyMargin to 0 788 // 789 if (ThreadSafetyMargin > 0) { 790 address stack_bottom = os::current_stack_base() - os::current_stack_size(); 791 792 // not safe if our stack extends below the safety margin 793 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address(); 794 } else { 795 return true; 796 } 797 } else { 798 // Floating stack LinuxThreads or NPTL: 799 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When 800 // there's not enough space left, pthread_create() will fail. If we come 801 // here, that means enough space has been reserved for stack. 802 return true; 803 } 804} 805 806// Thread start routine for all newly created threads 807static void *java_start(Thread *thread) { 808 // Try to randomize the cache line index of hot stack frames. 809 // This helps when threads of the same stack traces evict each other's 810 // cache lines. The threads can be either from the same JVM instance, or 811 // from different JVM instances. The benefit is especially true for 812 // processors with hyperthreading technology. 813 static int counter = 0; 814 int pid = os::current_process_id(); 815 alloca(((pid ^ counter++) & 7) * 128); 816 817 ThreadLocalStorage::set_thread(thread); 818 819 OSThread* osthread = thread->osthread(); 820 Monitor* sync = osthread->startThread_lock(); 821 822 // non floating stack LinuxThreads needs extra check, see above 823 if (!_thread_safety_check(thread)) { 824 // notify parent thread 825 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 826 osthread->set_state(ZOMBIE); 827 sync->notify_all(); 828 return NULL; 829 } 830 831 // thread_id is kernel thread id (similar to Solaris LWP id) 832 osthread->set_thread_id(os::Linux::gettid()); 833 834 if (UseNUMA) { 835 int lgrp_id = os::numa_get_group_id(); 836 if (lgrp_id != -1) { 837 thread->set_lgrp_id(lgrp_id); 838 } 839 } 840 // initialize signal mask for this thread 841 os::Linux::hotspot_sigmask(thread); 842 843 // initialize floating point control register 844 os::Linux::init_thread_fpu_state(); 845 846 // handshaking with parent thread 847 { 848 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 849 850 // notify parent thread 851 osthread->set_state(INITIALIZED); 852 sync->notify_all(); 853 854 // wait until os::start_thread() 855 while (osthread->get_state() == INITIALIZED) { 856 sync->wait(Mutex::_no_safepoint_check_flag); 857 } 858 } 859 860 // call one more level start routine 861 thread->run(); 862 863 return 0; 864} 865 866bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) { 867 assert(thread->osthread() == NULL, "caller responsible"); 868 869 // Allocate the OSThread object 870 OSThread* osthread = new OSThread(NULL, NULL); 871 if (osthread == NULL) { 872 return false; 873 } 874 875 // set the correct thread state 876 osthread->set_thread_type(thr_type); 877 878 // Initial state is ALLOCATED but not INITIALIZED 879 osthread->set_state(ALLOCATED); 880 881 thread->set_osthread(osthread); 882 883 // init thread attributes 884 pthread_attr_t attr; 885 pthread_attr_init(&attr); 886 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 887 888 // stack size 889 if (os::Linux::supports_variable_stack_size()) { 890 // calculate stack size if it's not specified by caller 891 if (stack_size == 0) { 892 stack_size = os::Linux::default_stack_size(thr_type); 893 894 switch (thr_type) { 895 case os::java_thread: 896 // Java threads use ThreadStackSize which default value can be 897 // changed with the flag -Xss 898 assert (JavaThread::stack_size_at_create() > 0, "this should be set"); 899 stack_size = JavaThread::stack_size_at_create(); 900 break; 901 case os::compiler_thread: 902 if (CompilerThreadStackSize > 0) { 903 stack_size = (size_t)(CompilerThreadStackSize * K); 904 break; 905 } // else fall through: 906 // use VMThreadStackSize if CompilerThreadStackSize is not defined 907 case os::vm_thread: 908 case os::pgc_thread: 909 case os::cgc_thread: 910 case os::watcher_thread: 911 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 912 break; 913 } 914 } 915 916 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 917 pthread_attr_setstacksize(&attr, stack_size); 918 } else { 919 // let pthread_create() pick the default value. 920 } 921 922 // glibc guard page 923 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 924 925 ThreadState state; 926 927 { 928 // Serialize thread creation if we are running with fixed stack LinuxThreads 929 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack(); 930 if (lock) { 931 os::Linux::createThread_lock()->lock_without_safepoint_check(); 932 } 933 934 pthread_t tid; 935 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 936 937 pthread_attr_destroy(&attr); 938 939 if (ret != 0) { 940 if (PrintMiscellaneous && (Verbose || WizardMode)) { 941 perror("pthread_create()"); 942 } 943 // Need to clean up stuff we've allocated so far 944 thread->set_osthread(NULL); 945 delete osthread; 946 if (lock) os::Linux::createThread_lock()->unlock(); 947 return false; 948 } 949 950 // Store pthread info into the OSThread 951 osthread->set_pthread_id(tid); 952 953 // Wait until child thread is either initialized or aborted 954 { 955 Monitor* sync_with_child = osthread->startThread_lock(); 956 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 957 while ((state = osthread->get_state()) == ALLOCATED) { 958 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 959 } 960 } 961 962 if (lock) { 963 os::Linux::createThread_lock()->unlock(); 964 } 965 } 966 967 // Aborted due to thread limit being reached 968 if (state == ZOMBIE) { 969 thread->set_osthread(NULL); 970 delete osthread; 971 return false; 972 } 973 974 // The thread is returned suspended (in state INITIALIZED), 975 // and is started higher up in the call chain 976 assert(state == INITIALIZED, "race condition"); 977 return true; 978} 979 980///////////////////////////////////////////////////////////////////////////// 981// attach existing thread 982 983// bootstrap the main thread 984bool os::create_main_thread(JavaThread* thread) { 985 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 986 return create_attached_thread(thread); 987} 988 989bool os::create_attached_thread(JavaThread* thread) { 990#ifdef ASSERT 991 thread->verify_not_published(); 992#endif 993 994 // Allocate the OSThread object 995 OSThread* osthread = new OSThread(NULL, NULL); 996 997 if (osthread == NULL) { 998 return false; 999 } 1000 1001 // Store pthread info into the OSThread 1002 osthread->set_thread_id(os::Linux::gettid()); 1003 osthread->set_pthread_id(::pthread_self()); 1004 1005 // initialize floating point control register 1006 os::Linux::init_thread_fpu_state(); 1007 1008 // Initial thread state is RUNNABLE 1009 osthread->set_state(RUNNABLE); 1010 1011 thread->set_osthread(osthread); 1012 1013 if (UseNUMA) { 1014 int lgrp_id = os::numa_get_group_id(); 1015 if (lgrp_id != -1) { 1016 thread->set_lgrp_id(lgrp_id); 1017 } 1018 } 1019 1020 if (os::Linux::is_initial_thread()) { 1021 // If current thread is initial thread, its stack is mapped on demand, 1022 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 1023 // the entire stack region to avoid SEGV in stack banging. 1024 // It is also useful to get around the heap-stack-gap problem on SuSE 1025 // kernel (see 4821821 for details). We first expand stack to the top 1026 // of yellow zone, then enable stack yellow zone (order is significant, 1027 // enabling yellow zone first will crash JVM on SuSE Linux), so there 1028 // is no gap between the last two virtual memory regions. 1029 1030 JavaThread *jt = (JavaThread *)thread; 1031 address addr = jt->stack_yellow_zone_base(); 1032 assert(addr != NULL, "initialization problem?"); 1033 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 1034 1035 osthread->set_expanding_stack(); 1036 os::Linux::manually_expand_stack(jt, addr); 1037 osthread->clear_expanding_stack(); 1038 } 1039 1040 // initialize signal mask for this thread 1041 // and save the caller's signal mask 1042 os::Linux::hotspot_sigmask(thread); 1043 1044 return true; 1045} 1046 1047void os::pd_start_thread(Thread* thread) { 1048 OSThread * osthread = thread->osthread(); 1049 assert(osthread->get_state() != INITIALIZED, "just checking"); 1050 Monitor* sync_with_child = osthread->startThread_lock(); 1051 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 1052 sync_with_child->notify(); 1053} 1054 1055// Free Linux resources related to the OSThread 1056void os::free_thread(OSThread* osthread) { 1057 assert(osthread != NULL, "osthread not set"); 1058 1059 if (Thread::current()->osthread() == osthread) { 1060 // Restore caller's signal mask 1061 sigset_t sigmask = osthread->caller_sigmask(); 1062 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1063 } 1064 1065 delete osthread; 1066} 1067 1068////////////////////////////////////////////////////////////////////////////// 1069// thread local storage 1070 1071int os::allocate_thread_local_storage() { 1072 pthread_key_t key; 1073 int rslt = pthread_key_create(&key, NULL); 1074 assert(rslt == 0, "cannot allocate thread local storage"); 1075 return (int)key; 1076} 1077 1078// Note: This is currently not used by VM, as we don't destroy TLS key 1079// on VM exit. 1080void os::free_thread_local_storage(int index) { 1081 int rslt = pthread_key_delete((pthread_key_t)index); 1082 assert(rslt == 0, "invalid index"); 1083} 1084 1085void os::thread_local_storage_at_put(int index, void* value) { 1086 int rslt = pthread_setspecific((pthread_key_t)index, value); 1087 assert(rslt == 0, "pthread_setspecific failed"); 1088} 1089 1090extern "C" Thread* get_thread() { 1091 return ThreadLocalStorage::thread(); 1092} 1093 1094////////////////////////////////////////////////////////////////////////////// 1095// initial thread 1096 1097// Check if current thread is the initial thread, similar to Solaris thr_main. 1098bool os::Linux::is_initial_thread(void) { 1099 char dummy; 1100 // If called before init complete, thread stack bottom will be null. 1101 // Can be called if fatal error occurs before initialization. 1102 if (initial_thread_stack_bottom() == NULL) return false; 1103 assert(initial_thread_stack_bottom() != NULL && 1104 initial_thread_stack_size() != 0, 1105 "os::init did not locate initial thread's stack region"); 1106 if ((address)&dummy >= initial_thread_stack_bottom() && 1107 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) 1108 return true; 1109 else return false; 1110} 1111 1112// Find the virtual memory area that contains addr 1113static bool find_vma(address addr, address* vma_low, address* vma_high) { 1114 FILE *fp = fopen("/proc/self/maps", "r"); 1115 if (fp) { 1116 address low, high; 1117 while (!feof(fp)) { 1118 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1119 if (low <= addr && addr < high) { 1120 if (vma_low) *vma_low = low; 1121 if (vma_high) *vma_high = high; 1122 fclose (fp); 1123 return true; 1124 } 1125 } 1126 for (;;) { 1127 int ch = fgetc(fp); 1128 if (ch == EOF || ch == (int)'\n') break; 1129 } 1130 } 1131 fclose(fp); 1132 } 1133 return false; 1134} 1135 1136// Locate initial thread stack. This special handling of initial thread stack 1137// is needed because pthread_getattr_np() on most (all?) Linux distros returns 1138// bogus value for initial thread. 1139void os::Linux::capture_initial_stack(size_t max_size) { 1140 // stack size is the easy part, get it from RLIMIT_STACK 1141 size_t stack_size; 1142 struct rlimit rlim; 1143 getrlimit(RLIMIT_STACK, &rlim); 1144 stack_size = rlim.rlim_cur; 1145 1146 // 6308388: a bug in ld.so will relocate its own .data section to the 1147 // lower end of primordial stack; reduce ulimit -s value a little bit 1148 // so we won't install guard page on ld.so's data section. 1149 stack_size -= 2 * page_size(); 1150 1151 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 1152 // 7.1, in both cases we will get 2G in return value. 1153 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 1154 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 1155 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 1156 // in case other parts in glibc still assumes 2M max stack size. 1157 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 1158#ifndef IA64 1159 if (stack_size > 2 * K * K) stack_size = 2 * K * K; 1160#else 1161 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 1162 if (stack_size > 4 * K * K) stack_size = 4 * K * K; 1163#endif 1164 1165 // Try to figure out where the stack base (top) is. This is harder. 1166 // 1167 // When an application is started, glibc saves the initial stack pointer in 1168 // a global variable "__libc_stack_end", which is then used by system 1169 // libraries. __libc_stack_end should be pretty close to stack top. The 1170 // variable is available since the very early days. However, because it is 1171 // a private interface, it could disappear in the future. 1172 // 1173 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1174 // to __libc_stack_end, it is very close to stack top, but isn't the real 1175 // stack top. Note that /proc may not exist if VM is running as a chroot 1176 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1177 // /proc/<pid>/stat could change in the future (though unlikely). 1178 // 1179 // We try __libc_stack_end first. If that doesn't work, look for 1180 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1181 // as a hint, which should work well in most cases. 1182 1183 uintptr_t stack_start; 1184 1185 // try __libc_stack_end first 1186 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1187 if (p && *p) { 1188 stack_start = *p; 1189 } else { 1190 // see if we can get the start_stack field from /proc/self/stat 1191 FILE *fp; 1192 int pid; 1193 char state; 1194 int ppid; 1195 int pgrp; 1196 int session; 1197 int nr; 1198 int tpgrp; 1199 unsigned long flags; 1200 unsigned long minflt; 1201 unsigned long cminflt; 1202 unsigned long majflt; 1203 unsigned long cmajflt; 1204 unsigned long utime; 1205 unsigned long stime; 1206 long cutime; 1207 long cstime; 1208 long prio; 1209 long nice; 1210 long junk; 1211 long it_real; 1212 uintptr_t start; 1213 uintptr_t vsize; 1214 intptr_t rss; 1215 uintptr_t rsslim; 1216 uintptr_t scodes; 1217 uintptr_t ecode; 1218 int i; 1219 1220 // Figure what the primordial thread stack base is. Code is inspired 1221 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1222 // followed by command name surrounded by parentheses, state, etc. 1223 char stat[2048]; 1224 int statlen; 1225 1226 fp = fopen("/proc/self/stat", "r"); 1227 if (fp) { 1228 statlen = fread(stat, 1, 2047, fp); 1229 stat[statlen] = '\0'; 1230 fclose(fp); 1231 1232 // Skip pid and the command string. Note that we could be dealing with 1233 // weird command names, e.g. user could decide to rename java launcher 1234 // to "java 1.4.2 :)", then the stat file would look like 1235 // 1234 (java 1.4.2 :)) R ... ... 1236 // We don't really need to know the command string, just find the last 1237 // occurrence of ")" and then start parsing from there. See bug 4726580. 1238 char * s = strrchr(stat, ')'); 1239 1240 i = 0; 1241 if (s) { 1242 // Skip blank chars 1243 do s++; while (isspace(*s)); 1244 1245#define _UFM UINTX_FORMAT 1246#define _DFM INTX_FORMAT 1247 1248 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */ 1249 /* 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 */ 1250 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, 1251 &state, /* 3 %c */ 1252 &ppid, /* 4 %d */ 1253 &pgrp, /* 5 %d */ 1254 &session, /* 6 %d */ 1255 &nr, /* 7 %d */ 1256 &tpgrp, /* 8 %d */ 1257 &flags, /* 9 %lu */ 1258 &minflt, /* 10 %lu */ 1259 &cminflt, /* 11 %lu */ 1260 &majflt, /* 12 %lu */ 1261 &cmajflt, /* 13 %lu */ 1262 &utime, /* 14 %lu */ 1263 &stime, /* 15 %lu */ 1264 &cutime, /* 16 %ld */ 1265 &cstime, /* 17 %ld */ 1266 &prio, /* 18 %ld */ 1267 &nice, /* 19 %ld */ 1268 &junk, /* 20 %ld */ 1269 &it_real, /* 21 %ld */ 1270 &start, /* 22 UINTX_FORMAT */ 1271 &vsize, /* 23 UINTX_FORMAT */ 1272 &rss, /* 24 INTX_FORMAT */ 1273 &rsslim, /* 25 UINTX_FORMAT */ 1274 &scodes, /* 26 UINTX_FORMAT */ 1275 &ecode, /* 27 UINTX_FORMAT */ 1276 &stack_start); /* 28 UINTX_FORMAT */ 1277 } 1278 1279#undef _UFM 1280#undef _DFM 1281 1282 if (i != 28 - 2) { 1283 assert(false, "Bad conversion from /proc/self/stat"); 1284 // product mode - assume we are the initial thread, good luck in the 1285 // embedded case. 1286 warning("Can't detect initial thread stack location - bad conversion"); 1287 stack_start = (uintptr_t) &rlim; 1288 } 1289 } else { 1290 // For some reason we can't open /proc/self/stat (for example, running on 1291 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1292 // most cases, so don't abort: 1293 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1294 stack_start = (uintptr_t) &rlim; 1295 } 1296 } 1297 1298 // Now we have a pointer (stack_start) very close to the stack top, the 1299 // next thing to do is to figure out the exact location of stack top. We 1300 // can find out the virtual memory area that contains stack_start by 1301 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1302 // and its upper limit is the real stack top. (again, this would fail if 1303 // running inside chroot, because /proc may not exist.) 1304 1305 uintptr_t stack_top; 1306 address low, high; 1307 if (find_vma((address)stack_start, &low, &high)) { 1308 // success, "high" is the true stack top. (ignore "low", because initial 1309 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1310 stack_top = (uintptr_t)high; 1311 } else { 1312 // failed, likely because /proc/self/maps does not exist 1313 warning("Can't detect initial thread stack location - find_vma failed"); 1314 // best effort: stack_start is normally within a few pages below the real 1315 // stack top, use it as stack top, and reduce stack size so we won't put 1316 // guard page outside stack. 1317 stack_top = stack_start; 1318 stack_size -= 16 * page_size(); 1319 } 1320 1321 // stack_top could be partially down the page so align it 1322 stack_top = align_size_up(stack_top, page_size()); 1323 1324 if (max_size && stack_size > max_size) { 1325 _initial_thread_stack_size = max_size; 1326 } else { 1327 _initial_thread_stack_size = stack_size; 1328 } 1329 1330 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1331 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1332} 1333 1334//////////////////////////////////////////////////////////////////////////////// 1335// time support 1336 1337// Time since start-up in seconds to a fine granularity. 1338// Used by VMSelfDestructTimer and the MemProfiler. 1339double os::elapsedTime() { 1340 1341 return (double)(os::elapsed_counter()) * 0.000001; 1342} 1343 1344jlong os::elapsed_counter() { 1345 timeval time; 1346 int status = gettimeofday(&time, NULL); 1347 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count; 1348} 1349 1350jlong os::elapsed_frequency() { 1351 return (1000 * 1000); 1352} 1353 1354// For now, we say that linux does not support vtime. I have no idea 1355// whether it can actually be made to (DLD, 9/13/05). 1356 1357bool os::supports_vtime() { return false; } 1358bool os::enable_vtime() { return false; } 1359bool os::vtime_enabled() { return false; } 1360double os::elapsedVTime() { 1361 // better than nothing, but not much 1362 return elapsedTime(); 1363} 1364 1365jlong os::javaTimeMillis() { 1366 timeval time; 1367 int status = gettimeofday(&time, NULL); 1368 assert(status != -1, "linux error"); 1369 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1370} 1371 1372#ifndef CLOCK_MONOTONIC 1373#define CLOCK_MONOTONIC (1) 1374#endif 1375 1376void os::Linux::clock_init() { 1377 // we do dlopen's in this particular order due to bug in linux 1378 // dynamical loader (see 6348968) leading to crash on exit 1379 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1380 if (handle == NULL) { 1381 handle = dlopen("librt.so", RTLD_LAZY); 1382 } 1383 1384 if (handle) { 1385 int (*clock_getres_func)(clockid_t, struct timespec*) = 1386 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1387 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1388 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1389 if (clock_getres_func && clock_gettime_func) { 1390 // See if monotonic clock is supported by the kernel. Note that some 1391 // early implementations simply return kernel jiffies (updated every 1392 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1393 // for nano time (though the monotonic property is still nice to have). 1394 // It's fixed in newer kernels, however clock_getres() still returns 1395 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1396 // resolution for now. Hopefully as people move to new kernels, this 1397 // won't be a problem. 1398 struct timespec res; 1399 struct timespec tp; 1400 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1401 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1402 // yes, monotonic clock is supported 1403 _clock_gettime = clock_gettime_func; 1404 } else { 1405 // close librt if there is no monotonic clock 1406 dlclose(handle); 1407 } 1408 } 1409 } 1410} 1411 1412#ifndef SYS_clock_getres 1413 1414#if defined(IA32) || defined(AMD64) 1415#define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1416#define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1417#else 1418#warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1419#define sys_clock_getres(x,y) -1 1420#endif 1421 1422#else 1423#define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1424#endif 1425 1426void os::Linux::fast_thread_clock_init() { 1427 if (!UseLinuxPosixThreadCPUClocks) { 1428 return; 1429 } 1430 clockid_t clockid; 1431 struct timespec tp; 1432 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1433 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1434 1435 // Switch to using fast clocks for thread cpu time if 1436 // the sys_clock_getres() returns 0 error code. 1437 // Note, that some kernels may support the current thread 1438 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1439 // returned by the pthread_getcpuclockid(). 1440 // If the fast Posix clocks are supported then the sys_clock_getres() 1441 // must return at least tp.tv_sec == 0 which means a resolution 1442 // better than 1 sec. This is extra check for reliability. 1443 1444 if(pthread_getcpuclockid_func && 1445 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1446 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1447 1448 _supports_fast_thread_cpu_time = true; 1449 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1450 } 1451} 1452 1453jlong os::javaTimeNanos() { 1454 if (Linux::supports_monotonic_clock()) { 1455 struct timespec tp; 1456 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1457 assert(status == 0, "gettime error"); 1458 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1459 return result; 1460 } else { 1461 timeval time; 1462 int status = gettimeofday(&time, NULL); 1463 assert(status != -1, "linux error"); 1464 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1465 return 1000 * usecs; 1466 } 1467} 1468 1469void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1470 if (Linux::supports_monotonic_clock()) { 1471 info_ptr->max_value = ALL_64_BITS; 1472 1473 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1474 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1475 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1476 } else { 1477 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1478 info_ptr->max_value = ALL_64_BITS; 1479 1480 // gettimeofday is a real time clock so it skips 1481 info_ptr->may_skip_backward = true; 1482 info_ptr->may_skip_forward = true; 1483 } 1484 1485 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1486} 1487 1488// Return the real, user, and system times in seconds from an 1489// arbitrary fixed point in the past. 1490bool os::getTimesSecs(double* process_real_time, 1491 double* process_user_time, 1492 double* process_system_time) { 1493 struct tms ticks; 1494 clock_t real_ticks = times(&ticks); 1495 1496 if (real_ticks == (clock_t) (-1)) { 1497 return false; 1498 } else { 1499 double ticks_per_second = (double) clock_tics_per_sec; 1500 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1501 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1502 *process_real_time = ((double) real_ticks) / ticks_per_second; 1503 1504 return true; 1505 } 1506} 1507 1508 1509char * os::local_time_string(char *buf, size_t buflen) { 1510 struct tm t; 1511 time_t long_time; 1512 time(&long_time); 1513 localtime_r(&long_time, &t); 1514 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1515 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1516 t.tm_hour, t.tm_min, t.tm_sec); 1517 return buf; 1518} 1519 1520struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1521 return localtime_r(clock, res); 1522} 1523 1524//////////////////////////////////////////////////////////////////////////////// 1525// runtime exit support 1526 1527// Note: os::shutdown() might be called very early during initialization, or 1528// called from signal handler. Before adding something to os::shutdown(), make 1529// sure it is async-safe and can handle partially initialized VM. 1530void os::shutdown() { 1531 1532 // allow PerfMemory to attempt cleanup of any persistent resources 1533 perfMemory_exit(); 1534 1535 // needs to remove object in file system 1536 AttachListener::abort(); 1537 1538 // flush buffered output, finish log files 1539 ostream_abort(); 1540 1541 // Check for abort hook 1542 abort_hook_t abort_hook = Arguments::abort_hook(); 1543 if (abort_hook != NULL) { 1544 abort_hook(); 1545 } 1546 1547} 1548 1549// Note: os::abort() might be called very early during initialization, or 1550// called from signal handler. Before adding something to os::abort(), make 1551// sure it is async-safe and can handle partially initialized VM. 1552void os::abort(bool dump_core) { 1553 os::shutdown(); 1554 if (dump_core) { 1555#ifndef PRODUCT 1556 fdStream out(defaultStream::output_fd()); 1557 out.print_raw("Current thread is "); 1558 char buf[16]; 1559 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1560 out.print_raw_cr(buf); 1561 out.print_raw_cr("Dumping core ..."); 1562#endif 1563 ::abort(); // dump core 1564 } 1565 1566 ::exit(1); 1567} 1568 1569// Die immediately, no exit hook, no abort hook, no cleanup. 1570void os::die() { 1571 // _exit() on LinuxThreads only kills current thread 1572 ::abort(); 1573} 1574 1575// unused on linux for now. 1576void os::set_error_file(const char *logfile) {} 1577 1578 1579// This method is a copy of JDK's sysGetLastErrorString 1580// from src/solaris/hpi/src/system_md.c 1581 1582size_t os::lasterror(char *buf, size_t len) { 1583 1584 if (errno == 0) return 0; 1585 1586 const char *s = ::strerror(errno); 1587 size_t n = ::strlen(s); 1588 if (n >= len) { 1589 n = len - 1; 1590 } 1591 ::strncpy(buf, s, n); 1592 buf[n] = '\0'; 1593 return n; 1594} 1595 1596intx os::current_thread_id() { return (intx)pthread_self(); } 1597int os::current_process_id() { 1598 1599 // Under the old linux thread library, linux gives each thread 1600 // its own process id. Because of this each thread will return 1601 // a different pid if this method were to return the result 1602 // of getpid(2). Linux provides no api that returns the pid 1603 // of the launcher thread for the vm. This implementation 1604 // returns a unique pid, the pid of the launcher thread 1605 // that starts the vm 'process'. 1606 1607 // Under the NPTL, getpid() returns the same pid as the 1608 // launcher thread rather than a unique pid per thread. 1609 // Use gettid() if you want the old pre NPTL behaviour. 1610 1611 // if you are looking for the result of a call to getpid() that 1612 // returns a unique pid for the calling thread, then look at the 1613 // OSThread::thread_id() method in osThread_linux.hpp file 1614 1615 return (int)(_initial_pid ? _initial_pid : getpid()); 1616} 1617 1618// DLL functions 1619 1620const char* os::dll_file_extension() { return ".so"; } 1621 1622// This must be hard coded because it's the system's temporary 1623// directory not the java application's temp directory, ala java.io.tmpdir. 1624const char* os::get_temp_directory() { return "/tmp"; } 1625 1626static bool file_exists(const char* filename) { 1627 struct stat statbuf; 1628 if (filename == NULL || strlen(filename) == 0) { 1629 return false; 1630 } 1631 return os::stat(filename, &statbuf) == 0; 1632} 1633 1634void os::dll_build_name(char* buffer, size_t buflen, 1635 const char* pname, const char* fname) { 1636 // Copied from libhpi 1637 const size_t pnamelen = pname ? strlen(pname) : 0; 1638 1639 // Quietly truncate on buffer overflow. Should be an error. 1640 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1641 *buffer = '\0'; 1642 return; 1643 } 1644 1645 if (pnamelen == 0) { 1646 snprintf(buffer, buflen, "lib%s.so", fname); 1647 } else if (strchr(pname, *os::path_separator()) != NULL) { 1648 int n; 1649 char** pelements = split_path(pname, &n); 1650 for (int i = 0 ; i < n ; i++) { 1651 // Really shouldn't be NULL, but check can't hurt 1652 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1653 continue; // skip the empty path values 1654 } 1655 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1656 if (file_exists(buffer)) { 1657 break; 1658 } 1659 } 1660 // release the storage 1661 for (int i = 0 ; i < n ; i++) { 1662 if (pelements[i] != NULL) { 1663 FREE_C_HEAP_ARRAY(char, pelements[i]); 1664 } 1665 } 1666 if (pelements != NULL) { 1667 FREE_C_HEAP_ARRAY(char*, pelements); 1668 } 1669 } else { 1670 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1671 } 1672} 1673 1674const char* os::get_current_directory(char *buf, int buflen) { 1675 return getcwd(buf, buflen); 1676} 1677 1678// check if addr is inside libjvm[_g].so 1679bool os::address_is_in_vm(address addr) { 1680 static address libjvm_base_addr; 1681 Dl_info dlinfo; 1682 1683 if (libjvm_base_addr == NULL) { 1684 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo); 1685 libjvm_base_addr = (address)dlinfo.dli_fbase; 1686 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1687 } 1688 1689 if (dladdr((void *)addr, &dlinfo)) { 1690 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1691 } 1692 1693 return false; 1694} 1695 1696bool os::dll_address_to_function_name(address addr, char *buf, 1697 int buflen, int *offset) { 1698 Dl_info dlinfo; 1699 1700 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) { 1701 if (buf != NULL) { 1702 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) { 1703 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1704 } 1705 } 1706 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1707 return true; 1708 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) { 1709 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1710 dlinfo.dli_fname, buf, buflen, offset) == Decoder::no_error) { 1711 return true; 1712 } 1713 } 1714 1715 if (buf != NULL) buf[0] = '\0'; 1716 if (offset != NULL) *offset = -1; 1717 return false; 1718} 1719 1720struct _address_to_library_name { 1721 address addr; // input : memory address 1722 size_t buflen; // size of fname 1723 char* fname; // output: library name 1724 address base; // library base addr 1725}; 1726 1727static int address_to_library_name_callback(struct dl_phdr_info *info, 1728 size_t size, void *data) { 1729 int i; 1730 bool found = false; 1731 address libbase = NULL; 1732 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1733 1734 // iterate through all loadable segments 1735 for (i = 0; i < info->dlpi_phnum; i++) { 1736 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1737 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1738 // base address of a library is the lowest address of its loaded 1739 // segments. 1740 if (libbase == NULL || libbase > segbase) { 1741 libbase = segbase; 1742 } 1743 // see if 'addr' is within current segment 1744 if (segbase <= d->addr && 1745 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1746 found = true; 1747 } 1748 } 1749 } 1750 1751 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1752 // so dll_address_to_library_name() can fall through to use dladdr() which 1753 // can figure out executable name from argv[0]. 1754 if (found && info->dlpi_name && info->dlpi_name[0]) { 1755 d->base = libbase; 1756 if (d->fname) { 1757 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1758 } 1759 return 1; 1760 } 1761 return 0; 1762} 1763 1764bool os::dll_address_to_library_name(address addr, char* buf, 1765 int buflen, int* offset) { 1766 Dl_info dlinfo; 1767 struct _address_to_library_name data; 1768 1769 // There is a bug in old glibc dladdr() implementation that it could resolve 1770 // to wrong library name if the .so file has a base address != NULL. Here 1771 // we iterate through the program headers of all loaded libraries to find 1772 // out which library 'addr' really belongs to. This workaround can be 1773 // removed once the minimum requirement for glibc is moved to 2.3.x. 1774 data.addr = addr; 1775 data.fname = buf; 1776 data.buflen = buflen; 1777 data.base = NULL; 1778 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1779 1780 if (rslt) { 1781 // buf already contains library name 1782 if (offset) *offset = addr - data.base; 1783 return true; 1784 } else if (dladdr((void*)addr, &dlinfo)){ 1785 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1786 if (offset) *offset = addr - (address)dlinfo.dli_fbase; 1787 return true; 1788 } else { 1789 if (buf) buf[0] = '\0'; 1790 if (offset) *offset = -1; 1791 return false; 1792 } 1793} 1794 1795 // Loads .dll/.so and 1796 // in case of error it checks if .dll/.so was built for the 1797 // same architecture as Hotspot is running on 1798 1799void * os::dll_load(const char *filename, char *ebuf, int ebuflen) 1800{ 1801 void * result= ::dlopen(filename, RTLD_LAZY); 1802 if (result != NULL) { 1803 // Successful loading 1804 return result; 1805 } 1806 1807 Elf32_Ehdr elf_head; 1808 1809 // Read system error message into ebuf 1810 // It may or may not be overwritten below 1811 ::strncpy(ebuf, ::dlerror(), ebuflen-1); 1812 ebuf[ebuflen-1]='\0'; 1813 int diag_msg_max_length=ebuflen-strlen(ebuf); 1814 char* diag_msg_buf=ebuf+strlen(ebuf); 1815 1816 if (diag_msg_max_length==0) { 1817 // No more space in ebuf for additional diagnostics message 1818 return NULL; 1819 } 1820 1821 1822 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1823 1824 if (file_descriptor < 0) { 1825 // Can't open library, report dlerror() message 1826 return NULL; 1827 } 1828 1829 bool failed_to_read_elf_head= 1830 (sizeof(elf_head)!= 1831 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ; 1832 1833 ::close(file_descriptor); 1834 if (failed_to_read_elf_head) { 1835 // file i/o error - report dlerror() msg 1836 return NULL; 1837 } 1838 1839 typedef struct { 1840 Elf32_Half code; // Actual value as defined in elf.h 1841 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1842 char elf_class; // 32 or 64 bit 1843 char endianess; // MSB or LSB 1844 char* name; // String representation 1845 } arch_t; 1846 1847 #ifndef EM_486 1848 #define EM_486 6 /* Intel 80486 */ 1849 #endif 1850 1851 static const arch_t arch_array[]={ 1852 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1853 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1854 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1855 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1856 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1857 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1858 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1859 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1860 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1861 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1862 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1863 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1864 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1865 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1866 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1867 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"} 1868 }; 1869 1870 #if (defined IA32) 1871 static Elf32_Half running_arch_code=EM_386; 1872 #elif (defined AMD64) 1873 static Elf32_Half running_arch_code=EM_X86_64; 1874 #elif (defined IA64) 1875 static Elf32_Half running_arch_code=EM_IA_64; 1876 #elif (defined __sparc) && (defined _LP64) 1877 static Elf32_Half running_arch_code=EM_SPARCV9; 1878 #elif (defined __sparc) && (!defined _LP64) 1879 static Elf32_Half running_arch_code=EM_SPARC; 1880 #elif (defined __powerpc64__) 1881 static Elf32_Half running_arch_code=EM_PPC64; 1882 #elif (defined __powerpc__) 1883 static Elf32_Half running_arch_code=EM_PPC; 1884 #elif (defined ARM) 1885 static Elf32_Half running_arch_code=EM_ARM; 1886 #elif (defined S390) 1887 static Elf32_Half running_arch_code=EM_S390; 1888 #elif (defined ALPHA) 1889 static Elf32_Half running_arch_code=EM_ALPHA; 1890 #elif (defined MIPSEL) 1891 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1892 #elif (defined PARISC) 1893 static Elf32_Half running_arch_code=EM_PARISC; 1894 #elif (defined MIPS) 1895 static Elf32_Half running_arch_code=EM_MIPS; 1896 #elif (defined M68K) 1897 static Elf32_Half running_arch_code=EM_68K; 1898 #else 1899 #error Method os::dll_load requires that one of following is defined:\ 1900 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K 1901 #endif 1902 1903 // Identify compatability class for VM's architecture and library's architecture 1904 // Obtain string descriptions for architectures 1905 1906 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1907 int running_arch_index=-1; 1908 1909 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) { 1910 if (running_arch_code == arch_array[i].code) { 1911 running_arch_index = i; 1912 } 1913 if (lib_arch.code == arch_array[i].code) { 1914 lib_arch.compat_class = arch_array[i].compat_class; 1915 lib_arch.name = arch_array[i].name; 1916 } 1917 } 1918 1919 assert(running_arch_index != -1, 1920 "Didn't find running architecture code (running_arch_code) in arch_array"); 1921 if (running_arch_index == -1) { 1922 // Even though running architecture detection failed 1923 // we may still continue with reporting dlerror() message 1924 return NULL; 1925 } 1926 1927 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1928 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1929 return NULL; 1930 } 1931 1932#ifndef S390 1933 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1934 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1935 return NULL; 1936 } 1937#endif // !S390 1938 1939 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1940 if ( lib_arch.name!=NULL ) { 1941 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1942 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1943 lib_arch.name, arch_array[running_arch_index].name); 1944 } else { 1945 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1946 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1947 lib_arch.code, 1948 arch_array[running_arch_index].name); 1949 } 1950 } 1951 1952 return NULL; 1953} 1954 1955/* 1956 * glibc-2.0 libdl is not MT safe. If you are building with any glibc, 1957 * chances are you might want to run the generated bits against glibc-2.0 1958 * libdl.so, so always use locking for any version of glibc. 1959 */ 1960void* os::dll_lookup(void* handle, const char* name) { 1961 pthread_mutex_lock(&dl_mutex); 1962 void* res = dlsym(handle, name); 1963 pthread_mutex_unlock(&dl_mutex); 1964 return res; 1965} 1966 1967 1968static bool _print_ascii_file(const char* filename, outputStream* st) { 1969 int fd = ::open(filename, O_RDONLY); 1970 if (fd == -1) { 1971 return false; 1972 } 1973 1974 char buf[32]; 1975 int bytes; 1976 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 1977 st->print_raw(buf, bytes); 1978 } 1979 1980 ::close(fd); 1981 1982 return true; 1983} 1984 1985void os::print_dll_info(outputStream *st) { 1986 st->print_cr("Dynamic libraries:"); 1987 1988 char fname[32]; 1989 pid_t pid = os::Linux::gettid(); 1990 1991 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1992 1993 if (!_print_ascii_file(fname, st)) { 1994 st->print("Can not get library information for pid = %d\n", pid); 1995 } 1996} 1997 1998 1999void os::print_os_info(outputStream* st) { 2000 st->print("OS:"); 2001 2002 // Try to identify popular distros. 2003 // Most Linux distributions have /etc/XXX-release file, which contains 2004 // the OS version string. Some have more than one /etc/XXX-release file 2005 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.), 2006 // so the order is important. 2007 if (!_print_ascii_file("/etc/mandrake-release", st) && 2008 !_print_ascii_file("/etc/sun-release", st) && 2009 !_print_ascii_file("/etc/redhat-release", st) && 2010 !_print_ascii_file("/etc/SuSE-release", st) && 2011 !_print_ascii_file("/etc/turbolinux-release", st) && 2012 !_print_ascii_file("/etc/gentoo-release", st) && 2013 !_print_ascii_file("/etc/debian_version", st) && 2014 !_print_ascii_file("/etc/ltib-release", st) && 2015 !_print_ascii_file("/etc/angstrom-version", st)) { 2016 st->print("Linux"); 2017 } 2018 st->cr(); 2019 2020 // kernel 2021 st->print("uname:"); 2022 struct utsname name; 2023 uname(&name); 2024 st->print(name.sysname); st->print(" "); 2025 st->print(name.release); st->print(" "); 2026 st->print(name.version); st->print(" "); 2027 st->print(name.machine); 2028 st->cr(); 2029 2030 // Print warning if unsafe chroot environment detected 2031 if (unsafe_chroot_detected) { 2032 st->print("WARNING!! "); 2033 st->print_cr(unstable_chroot_error); 2034 } 2035 2036 // libc, pthread 2037 st->print("libc:"); 2038 st->print(os::Linux::glibc_version()); st->print(" "); 2039 st->print(os::Linux::libpthread_version()); st->print(" "); 2040 if (os::Linux::is_LinuxThreads()) { 2041 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed"); 2042 } 2043 st->cr(); 2044 2045 // rlimit 2046 st->print("rlimit:"); 2047 struct rlimit rlim; 2048 2049 st->print(" STACK "); 2050 getrlimit(RLIMIT_STACK, &rlim); 2051 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2052 else st->print("%uk", rlim.rlim_cur >> 10); 2053 2054 st->print(", CORE "); 2055 getrlimit(RLIMIT_CORE, &rlim); 2056 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2057 else st->print("%uk", rlim.rlim_cur >> 10); 2058 2059 st->print(", NPROC "); 2060 getrlimit(RLIMIT_NPROC, &rlim); 2061 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2062 else st->print("%d", rlim.rlim_cur); 2063 2064 st->print(", NOFILE "); 2065 getrlimit(RLIMIT_NOFILE, &rlim); 2066 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2067 else st->print("%d", rlim.rlim_cur); 2068 2069 st->print(", AS "); 2070 getrlimit(RLIMIT_AS, &rlim); 2071 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2072 else st->print("%uk", rlim.rlim_cur >> 10); 2073 st->cr(); 2074 2075 // load average 2076 st->print("load average:"); 2077 double loadavg[3]; 2078 os::loadavg(loadavg, 3); 2079 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]); 2080 st->cr(); 2081 2082 // meminfo 2083 st->print("\n/proc/meminfo:\n"); 2084 _print_ascii_file("/proc/meminfo", st); 2085 st->cr(); 2086} 2087 2088void os::print_memory_info(outputStream* st) { 2089 2090 st->print("Memory:"); 2091 st->print(" %dk page", os::vm_page_size()>>10); 2092 2093 // values in struct sysinfo are "unsigned long" 2094 struct sysinfo si; 2095 sysinfo(&si); 2096 2097 st->print(", physical " UINT64_FORMAT "k", 2098 os::physical_memory() >> 10); 2099 st->print("(" UINT64_FORMAT "k free)", 2100 os::available_memory() >> 10); 2101 st->print(", swap " UINT64_FORMAT "k", 2102 ((jlong)si.totalswap * si.mem_unit) >> 10); 2103 st->print("(" UINT64_FORMAT "k free)", 2104 ((jlong)si.freeswap * si.mem_unit) >> 10); 2105 st->cr(); 2106} 2107 2108// Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific 2109// but they're the same for all the linux arch that we support 2110// and they're the same for solaris but there's no common place to put this. 2111const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR", 2112 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG", 2113 "ILL_COPROC", "ILL_BADSTK" }; 2114 2115const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV", 2116 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES", 2117 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" }; 2118 2119const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" }; 2120 2121const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" }; 2122 2123void os::print_siginfo(outputStream* st, void* siginfo) { 2124 st->print("siginfo:"); 2125 2126 const int buflen = 100; 2127 char buf[buflen]; 2128 siginfo_t *si = (siginfo_t*)siginfo; 2129 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen)); 2130 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) { 2131 st->print("si_errno=%s", buf); 2132 } else { 2133 st->print("si_errno=%d", si->si_errno); 2134 } 2135 const int c = si->si_code; 2136 assert(c > 0, "unexpected si_code"); 2137 switch (si->si_signo) { 2138 case SIGILL: 2139 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]); 2140 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2141 break; 2142 case SIGFPE: 2143 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]); 2144 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2145 break; 2146 case SIGSEGV: 2147 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]); 2148 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2149 break; 2150 case SIGBUS: 2151 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]); 2152 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2153 break; 2154 default: 2155 st->print(", si_code=%d", si->si_code); 2156 // no si_addr 2157 } 2158 2159 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2160 UseSharedSpaces) { 2161 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2162 if (mapinfo->is_in_shared_space(si->si_addr)) { 2163 st->print("\n\nError accessing class data sharing archive." \ 2164 " Mapped file inaccessible during execution, " \ 2165 " possible disk/network problem."); 2166 } 2167 } 2168 st->cr(); 2169} 2170 2171 2172static void print_signal_handler(outputStream* st, int sig, 2173 char* buf, size_t buflen); 2174 2175void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2176 st->print_cr("Signal Handlers:"); 2177 print_signal_handler(st, SIGSEGV, buf, buflen); 2178 print_signal_handler(st, SIGBUS , buf, buflen); 2179 print_signal_handler(st, SIGFPE , buf, buflen); 2180 print_signal_handler(st, SIGPIPE, buf, buflen); 2181 print_signal_handler(st, SIGXFSZ, buf, buflen); 2182 print_signal_handler(st, SIGILL , buf, buflen); 2183 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2184 print_signal_handler(st, SR_signum, buf, buflen); 2185 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2186 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2187 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2188 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2189} 2190 2191static char saved_jvm_path[MAXPATHLEN] = {0}; 2192 2193// Find the full path to the current module, libjvm.so or libjvm_g.so 2194void os::jvm_path(char *buf, jint buflen) { 2195 // Error checking. 2196 if (buflen < MAXPATHLEN) { 2197 assert(false, "must use a large-enough buffer"); 2198 buf[0] = '\0'; 2199 return; 2200 } 2201 // Lazy resolve the path to current module. 2202 if (saved_jvm_path[0] != 0) { 2203 strcpy(buf, saved_jvm_path); 2204 return; 2205 } 2206 2207 char dli_fname[MAXPATHLEN]; 2208 bool ret = dll_address_to_library_name( 2209 CAST_FROM_FN_PTR(address, os::jvm_path), 2210 dli_fname, sizeof(dli_fname), NULL); 2211 assert(ret != 0, "cannot locate libjvm"); 2212 char *rp = realpath(dli_fname, buf); 2213 if (rp == NULL) 2214 return; 2215 2216 if (Arguments::created_by_gamma_launcher()) { 2217 // Support for the gamma launcher. Typical value for buf is 2218 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at 2219 // the right place in the string, then assume we are installed in a JDK and 2220 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix 2221 // up the path so it looks like libjvm.so is installed there (append a 2222 // fake suffix hotspot/libjvm.so). 2223 const char *p = buf + strlen(buf) - 1; 2224 for (int count = 0; p > buf && count < 5; ++count) { 2225 for (--p; p > buf && *p != '/'; --p) 2226 /* empty */ ; 2227 } 2228 2229 if (strncmp(p, "/jre/lib/", 9) != 0) { 2230 // Look for JAVA_HOME in the environment. 2231 char* java_home_var = ::getenv("JAVA_HOME"); 2232 if (java_home_var != NULL && java_home_var[0] != 0) { 2233 char* jrelib_p; 2234 int len; 2235 2236 // Check the current module name "libjvm.so" or "libjvm_g.so". 2237 p = strrchr(buf, '/'); 2238 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2239 p = strstr(p, "_g") ? "_g" : ""; 2240 2241 rp = realpath(java_home_var, buf); 2242 if (rp == NULL) 2243 return; 2244 2245 // determine if this is a legacy image or modules image 2246 // modules image doesn't have "jre" subdirectory 2247 len = strlen(buf); 2248 jrelib_p = buf + len; 2249 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2250 if (0 != access(buf, F_OK)) { 2251 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2252 } 2253 2254 if (0 == access(buf, F_OK)) { 2255 // Use current module name "libjvm[_g].so" instead of 2256 // "libjvm"debug_only("_g")".so" since for fastdebug version 2257 // we should have "libjvm.so" but debug_only("_g") adds "_g"! 2258 len = strlen(buf); 2259 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p); 2260 } else { 2261 // Go back to path of .so 2262 rp = realpath(dli_fname, buf); 2263 if (rp == NULL) 2264 return; 2265 } 2266 } 2267 } 2268 } 2269 2270 strcpy(saved_jvm_path, buf); 2271} 2272 2273void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2274 // no prefix required, not even "_" 2275} 2276 2277void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2278 // no suffix required 2279} 2280 2281//////////////////////////////////////////////////////////////////////////////// 2282// sun.misc.Signal support 2283 2284static volatile jint sigint_count = 0; 2285 2286static void 2287UserHandler(int sig, void *siginfo, void *context) { 2288 // 4511530 - sem_post is serialized and handled by the manager thread. When 2289 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2290 // don't want to flood the manager thread with sem_post requests. 2291 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) 2292 return; 2293 2294 // Ctrl-C is pressed during error reporting, likely because the error 2295 // handler fails to abort. Let VM die immediately. 2296 if (sig == SIGINT && is_error_reported()) { 2297 os::die(); 2298 } 2299 2300 os::signal_notify(sig); 2301} 2302 2303void* os::user_handler() { 2304 return CAST_FROM_FN_PTR(void*, UserHandler); 2305} 2306 2307extern "C" { 2308 typedef void (*sa_handler_t)(int); 2309 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2310} 2311 2312void* os::signal(int signal_number, void* handler) { 2313 struct sigaction sigAct, oldSigAct; 2314 2315 sigfillset(&(sigAct.sa_mask)); 2316 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2317 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2318 2319 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2320 // -1 means registration failed 2321 return (void *)-1; 2322 } 2323 2324 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2325} 2326 2327void os::signal_raise(int signal_number) { 2328 ::raise(signal_number); 2329} 2330 2331/* 2332 * The following code is moved from os.cpp for making this 2333 * code platform specific, which it is by its very nature. 2334 */ 2335 2336// Will be modified when max signal is changed to be dynamic 2337int os::sigexitnum_pd() { 2338 return NSIG; 2339} 2340 2341// a counter for each possible signal value 2342static volatile jint pending_signals[NSIG+1] = { 0 }; 2343 2344// Linux(POSIX) specific hand shaking semaphore. 2345static sem_t sig_sem; 2346 2347void os::signal_init_pd() { 2348 // Initialize signal structures 2349 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2350 2351 // Initialize signal semaphore 2352 ::sem_init(&sig_sem, 0, 0); 2353} 2354 2355void os::signal_notify(int sig) { 2356 Atomic::inc(&pending_signals[sig]); 2357 ::sem_post(&sig_sem); 2358} 2359 2360static int check_pending_signals(bool wait) { 2361 Atomic::store(0, &sigint_count); 2362 for (;;) { 2363 for (int i = 0; i < NSIG + 1; i++) { 2364 jint n = pending_signals[i]; 2365 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2366 return i; 2367 } 2368 } 2369 if (!wait) { 2370 return -1; 2371 } 2372 JavaThread *thread = JavaThread::current(); 2373 ThreadBlockInVM tbivm(thread); 2374 2375 bool threadIsSuspended; 2376 do { 2377 thread->set_suspend_equivalent(); 2378 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2379 ::sem_wait(&sig_sem); 2380 2381 // were we externally suspended while we were waiting? 2382 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2383 if (threadIsSuspended) { 2384 // 2385 // The semaphore has been incremented, but while we were waiting 2386 // another thread suspended us. We don't want to continue running 2387 // while suspended because that would surprise the thread that 2388 // suspended us. 2389 // 2390 ::sem_post(&sig_sem); 2391 2392 thread->java_suspend_self(); 2393 } 2394 } while (threadIsSuspended); 2395 } 2396} 2397 2398int os::signal_lookup() { 2399 return check_pending_signals(false); 2400} 2401 2402int os::signal_wait() { 2403 return check_pending_signals(true); 2404} 2405 2406//////////////////////////////////////////////////////////////////////////////// 2407// Virtual Memory 2408 2409int os::vm_page_size() { 2410 // Seems redundant as all get out 2411 assert(os::Linux::page_size() != -1, "must call os::init"); 2412 return os::Linux::page_size(); 2413} 2414 2415// Solaris allocates memory by pages. 2416int os::vm_allocation_granularity() { 2417 assert(os::Linux::page_size() != -1, "must call os::init"); 2418 return os::Linux::page_size(); 2419} 2420 2421// Rationale behind this function: 2422// current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2423// mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2424// samples for JITted code. Here we create private executable mapping over the code cache 2425// and then we can use standard (well, almost, as mapping can change) way to provide 2426// info for the reporting script by storing timestamp and location of symbol 2427void linux_wrap_code(char* base, size_t size) { 2428 static volatile jint cnt = 0; 2429 2430 if (!UseOprofile) { 2431 return; 2432 } 2433 2434 char buf[PATH_MAX+1]; 2435 int num = Atomic::add(1, &cnt); 2436 2437 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2438 os::get_temp_directory(), os::current_process_id(), num); 2439 unlink(buf); 2440 2441 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2442 2443 if (fd != -1) { 2444 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2445 if (rv != (off_t)-1) { 2446 if (::write(fd, "", 1) == 1) { 2447 mmap(base, size, 2448 PROT_READ|PROT_WRITE|PROT_EXEC, 2449 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2450 } 2451 } 2452 ::close(fd); 2453 unlink(buf); 2454 } 2455} 2456 2457// NOTE: Linux kernel does not really reserve the pages for us. 2458// All it does is to check if there are enough free pages 2459// left at the time of mmap(). This could be a potential 2460// problem. 2461bool os::commit_memory(char* addr, size_t size, bool exec) { 2462 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2463 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2464 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2465 return res != (uintptr_t) MAP_FAILED; 2466} 2467 2468// Define MAP_HUGETLB here so we can build HotSpot on old systems. 2469#ifndef MAP_HUGETLB 2470#define MAP_HUGETLB 0x40000 2471#endif 2472 2473// Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2474#ifndef MADV_HUGEPAGE 2475#define MADV_HUGEPAGE 14 2476#endif 2477 2478bool os::commit_memory(char* addr, size_t size, size_t alignment_hint, 2479 bool exec) { 2480 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) { 2481 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2482 uintptr_t res = 2483 (uintptr_t) ::mmap(addr, size, prot, 2484 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB, 2485 -1, 0); 2486 return res != (uintptr_t) MAP_FAILED; 2487 } 2488 2489 return commit_memory(addr, size, exec); 2490} 2491 2492void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2493 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) { 2494 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2495 // be supported or the memory may already be backed by huge pages. 2496 ::madvise(addr, bytes, MADV_HUGEPAGE); 2497 } 2498} 2499 2500void os::free_memory(char *addr, size_t bytes) { 2501 ::madvise(addr, bytes, MADV_DONTNEED); 2502} 2503 2504void os::numa_make_global(char *addr, size_t bytes) { 2505 Linux::numa_interleave_memory(addr, bytes); 2506} 2507 2508void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2509 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2510} 2511 2512bool os::numa_topology_changed() { return false; } 2513 2514size_t os::numa_get_groups_num() { 2515 int max_node = Linux::numa_max_node(); 2516 return max_node > 0 ? max_node + 1 : 1; 2517} 2518 2519int os::numa_get_group_id() { 2520 int cpu_id = Linux::sched_getcpu(); 2521 if (cpu_id != -1) { 2522 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2523 if (lgrp_id != -1) { 2524 return lgrp_id; 2525 } 2526 } 2527 return 0; 2528} 2529 2530size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2531 for (size_t i = 0; i < size; i++) { 2532 ids[i] = i; 2533 } 2534 return size; 2535} 2536 2537bool os::get_page_info(char *start, page_info* info) { 2538 return false; 2539} 2540 2541char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) { 2542 return end; 2543} 2544 2545// Something to do with the numa-aware allocator needs these symbols 2546extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2547extern "C" JNIEXPORT void numa_error(char *where) { } 2548extern "C" JNIEXPORT int fork1() { return fork(); } 2549 2550 2551// If we are running with libnuma version > 2, then we should 2552// be trying to use symbols with versions 1.1 2553// If we are running with earlier version, which did not have symbol versions, 2554// we should use the base version. 2555void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2556 void *f = dlvsym(handle, name, "libnuma_1.1"); 2557 if (f == NULL) { 2558 f = dlsym(handle, name); 2559 } 2560 return f; 2561} 2562 2563bool os::Linux::libnuma_init() { 2564 // sched_getcpu() should be in libc. 2565 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2566 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2567 2568 if (sched_getcpu() != -1) { // Does it work? 2569 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2570 if (handle != NULL) { 2571 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2572 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2573 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2574 libnuma_dlsym(handle, "numa_max_node"))); 2575 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2576 libnuma_dlsym(handle, "numa_available"))); 2577 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2578 libnuma_dlsym(handle, "numa_tonode_memory"))); 2579 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2580 libnuma_dlsym(handle, "numa_interleave_memory"))); 2581 2582 2583 if (numa_available() != -1) { 2584 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2585 // Create a cpu -> node mapping 2586 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true); 2587 rebuild_cpu_to_node_map(); 2588 return true; 2589 } 2590 } 2591 } 2592 return false; 2593} 2594 2595// rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2596// The table is later used in get_node_by_cpu(). 2597void os::Linux::rebuild_cpu_to_node_map() { 2598 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2599 // in libnuma (possible values are starting from 16, 2600 // and continuing up with every other power of 2, but less 2601 // than the maximum number of CPUs supported by kernel), and 2602 // is a subject to change (in libnuma version 2 the requirements 2603 // are more reasonable) we'll just hardcode the number they use 2604 // in the library. 2605 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2606 2607 size_t cpu_num = os::active_processor_count(); 2608 size_t cpu_map_size = NCPUS / BitsPerCLong; 2609 size_t cpu_map_valid_size = 2610 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2611 2612 cpu_to_node()->clear(); 2613 cpu_to_node()->at_grow(cpu_num - 1); 2614 size_t node_num = numa_get_groups_num(); 2615 2616 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size); 2617 for (size_t i = 0; i < node_num; i++) { 2618 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2619 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2620 if (cpu_map[j] != 0) { 2621 for (size_t k = 0; k < BitsPerCLong; k++) { 2622 if (cpu_map[j] & (1UL << k)) { 2623 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2624 } 2625 } 2626 } 2627 } 2628 } 2629 } 2630 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2631} 2632 2633int os::Linux::get_node_by_cpu(int cpu_id) { 2634 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2635 return cpu_to_node()->at(cpu_id); 2636 } 2637 return -1; 2638} 2639 2640GrowableArray<int>* os::Linux::_cpu_to_node; 2641os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2642os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2643os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2644os::Linux::numa_available_func_t os::Linux::_numa_available; 2645os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2646os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2647unsigned long* os::Linux::_numa_all_nodes; 2648 2649bool os::uncommit_memory(char* addr, size_t size) { 2650 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2651 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2652 return res != (uintptr_t) MAP_FAILED; 2653} 2654 2655// Linux uses a growable mapping for the stack, and if the mapping for 2656// the stack guard pages is not removed when we detach a thread the 2657// stack cannot grow beyond the pages where the stack guard was 2658// mapped. If at some point later in the process the stack expands to 2659// that point, the Linux kernel cannot expand the stack any further 2660// because the guard pages are in the way, and a segfault occurs. 2661// 2662// However, it's essential not to split the stack region by unmapping 2663// a region (leaving a hole) that's already part of the stack mapping, 2664// so if the stack mapping has already grown beyond the guard pages at 2665// the time we create them, we have to truncate the stack mapping. 2666// So, we need to know the extent of the stack mapping when 2667// create_stack_guard_pages() is called. 2668 2669// Find the bounds of the stack mapping. Return true for success. 2670// 2671// We only need this for stacks that are growable: at the time of 2672// writing thread stacks don't use growable mappings (i.e. those 2673// creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2674// only applies to the main thread. 2675 2676static 2677bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) { 2678 2679 char buf[128]; 2680 int fd, sz; 2681 2682 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) { 2683 return false; 2684 } 2685 2686 const char kw[] = "[stack]"; 2687 const int kwlen = sizeof(kw)-1; 2688 2689 // Address part of /proc/self/maps couldn't be more than 128 bytes 2690 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) { 2691 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) { 2692 // Extract addresses 2693 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) { 2694 uintptr_t sp = (uintptr_t) __builtin_frame_address(0); 2695 if (sp >= *bottom && sp <= *top) { 2696 ::close(fd); 2697 return true; 2698 } 2699 } 2700 } 2701 } 2702 2703 ::close(fd); 2704 return false; 2705} 2706 2707 2708// If the (growable) stack mapping already extends beyond the point 2709// where we're going to put our guard pages, truncate the mapping at 2710// that point by munmap()ping it. This ensures that when we later 2711// munmap() the guard pages we don't leave a hole in the stack 2712// mapping. This only affects the main/initial thread, but guard 2713// against future OS changes 2714bool os::create_stack_guard_pages(char* addr, size_t size) { 2715 uintptr_t stack_extent, stack_base; 2716 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2717 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2718 assert(os::Linux::is_initial_thread(), 2719 "growable stack in non-initial thread"); 2720 if (stack_extent < (uintptr_t)addr) 2721 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent); 2722 } 2723 2724 return os::commit_memory(addr, size); 2725} 2726 2727// If this is a growable mapping, remove the guard pages entirely by 2728// munmap()ping them. If not, just call uncommit_memory(). This only 2729// affects the main/initial thread, but guard against future OS changes 2730bool os::remove_stack_guard_pages(char* addr, size_t size) { 2731 uintptr_t stack_extent, stack_base; 2732 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2733 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2734 assert(os::Linux::is_initial_thread(), 2735 "growable stack in non-initial thread"); 2736 2737 return ::munmap(addr, size) == 0; 2738 } 2739 2740 return os::uncommit_memory(addr, size); 2741} 2742 2743static address _highest_vm_reserved_address = NULL; 2744 2745// If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 2746// at 'requested_addr'. If there are existing memory mappings at the same 2747// location, however, they will be overwritten. If 'fixed' is false, 2748// 'requested_addr' is only treated as a hint, the return value may or 2749// may not start from the requested address. Unlike Linux mmap(), this 2750// function returns NULL to indicate failure. 2751static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 2752 char * addr; 2753 int flags; 2754 2755 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 2756 if (fixed) { 2757 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 2758 flags |= MAP_FIXED; 2759 } 2760 2761 // Map uncommitted pages PROT_READ and PROT_WRITE, change access 2762 // to PROT_EXEC if executable when we commit the page. 2763 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE, 2764 flags, -1, 0); 2765 2766 if (addr != MAP_FAILED) { 2767 // anon_mmap() should only get called during VM initialization, 2768 // don't need lock (actually we can skip locking even it can be called 2769 // from multiple threads, because _highest_vm_reserved_address is just a 2770 // hint about the upper limit of non-stack memory regions.) 2771 if ((address)addr + bytes > _highest_vm_reserved_address) { 2772 _highest_vm_reserved_address = (address)addr + bytes; 2773 } 2774 } 2775 2776 return addr == MAP_FAILED ? NULL : addr; 2777} 2778 2779// Don't update _highest_vm_reserved_address, because there might be memory 2780// regions above addr + size. If so, releasing a memory region only creates 2781// a hole in the address space, it doesn't help prevent heap-stack collision. 2782// 2783static int anon_munmap(char * addr, size_t size) { 2784 return ::munmap(addr, size) == 0; 2785} 2786 2787char* os::reserve_memory(size_t bytes, char* requested_addr, 2788 size_t alignment_hint) { 2789 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 2790} 2791 2792bool os::release_memory(char* addr, size_t size) { 2793 return anon_munmap(addr, size); 2794} 2795 2796static address highest_vm_reserved_address() { 2797 return _highest_vm_reserved_address; 2798} 2799 2800static bool linux_mprotect(char* addr, size_t size, int prot) { 2801 // Linux wants the mprotect address argument to be page aligned. 2802 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 2803 2804 // According to SUSv3, mprotect() should only be used with mappings 2805 // established by mmap(), and mmap() always maps whole pages. Unaligned 2806 // 'addr' likely indicates problem in the VM (e.g. trying to change 2807 // protection of malloc'ed or statically allocated memory). Check the 2808 // caller if you hit this assert. 2809 assert(addr == bottom, "sanity check"); 2810 2811 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 2812 return ::mprotect(bottom, size, prot) == 0; 2813} 2814 2815// Set protections specified 2816bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 2817 bool is_committed) { 2818 unsigned int p = 0; 2819 switch (prot) { 2820 case MEM_PROT_NONE: p = PROT_NONE; break; 2821 case MEM_PROT_READ: p = PROT_READ; break; 2822 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 2823 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 2824 default: 2825 ShouldNotReachHere(); 2826 } 2827 // is_committed is unused. 2828 return linux_mprotect(addr, bytes, p); 2829} 2830 2831bool os::guard_memory(char* addr, size_t size) { 2832 return linux_mprotect(addr, size, PROT_NONE); 2833} 2834 2835bool os::unguard_memory(char* addr, size_t size) { 2836 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 2837} 2838 2839bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 2840 bool result = false; 2841 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE, 2842 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 2843 -1, 0); 2844 2845 if (p != (void *) -1) { 2846 // We don't know if this really is a huge page or not. 2847 FILE *fp = fopen("/proc/self/maps", "r"); 2848 if (fp) { 2849 while (!feof(fp)) { 2850 char chars[257]; 2851 long x = 0; 2852 if (fgets(chars, sizeof(chars), fp)) { 2853 if (sscanf(chars, "%lx-%*lx", &x) == 1 2854 && x == (long)p) { 2855 if (strstr (chars, "hugepage")) { 2856 result = true; 2857 break; 2858 } 2859 } 2860 } 2861 } 2862 fclose(fp); 2863 } 2864 munmap (p, page_size); 2865 if (result) 2866 return true; 2867 } 2868 2869 if (warn) { 2870 warning("HugeTLBFS is not supported by the operating system."); 2871 } 2872 2873 return result; 2874} 2875 2876/* 2877* Set the coredump_filter bits to include largepages in core dump (bit 6) 2878* 2879* From the coredump_filter documentation: 2880* 2881* - (bit 0) anonymous private memory 2882* - (bit 1) anonymous shared memory 2883* - (bit 2) file-backed private memory 2884* - (bit 3) file-backed shared memory 2885* - (bit 4) ELF header pages in file-backed private memory areas (it is 2886* effective only if the bit 2 is cleared) 2887* - (bit 5) hugetlb private memory 2888* - (bit 6) hugetlb shared memory 2889*/ 2890static void set_coredump_filter(void) { 2891 FILE *f; 2892 long cdm; 2893 2894 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 2895 return; 2896 } 2897 2898 if (fscanf(f, "%lx", &cdm) != 1) { 2899 fclose(f); 2900 return; 2901 } 2902 2903 rewind(f); 2904 2905 if ((cdm & LARGEPAGES_BIT) == 0) { 2906 cdm |= LARGEPAGES_BIT; 2907 fprintf(f, "%#lx", cdm); 2908 } 2909 2910 fclose(f); 2911} 2912 2913// Large page support 2914 2915static size_t _large_page_size = 0; 2916 2917bool os::large_page_init() { 2918 if (!UseLargePages) { 2919 UseHugeTLBFS = false; 2920 UseSHM = false; 2921 return false; 2922 } 2923 2924 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) { 2925 // Our user has not expressed a preference, so we'll try both. 2926 UseHugeTLBFS = UseSHM = true; 2927 } 2928 2929 if (LargePageSizeInBytes) { 2930 _large_page_size = LargePageSizeInBytes; 2931 } else { 2932 // large_page_size on Linux is used to round up heap size. x86 uses either 2933 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 2934 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 2935 // page as large as 256M. 2936 // 2937 // Here we try to figure out page size by parsing /proc/meminfo and looking 2938 // for a line with the following format: 2939 // Hugepagesize: 2048 kB 2940 // 2941 // If we can't determine the value (e.g. /proc is not mounted, or the text 2942 // format has been changed), we'll use the largest page size supported by 2943 // the processor. 2944 2945#ifndef ZERO 2946 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 2947 ARM_ONLY(2 * M) PPC_ONLY(4 * M); 2948#endif // ZERO 2949 2950 FILE *fp = fopen("/proc/meminfo", "r"); 2951 if (fp) { 2952 while (!feof(fp)) { 2953 int x = 0; 2954 char buf[16]; 2955 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 2956 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 2957 _large_page_size = x * K; 2958 break; 2959 } 2960 } else { 2961 // skip to next line 2962 for (;;) { 2963 int ch = fgetc(fp); 2964 if (ch == EOF || ch == (int)'\n') break; 2965 } 2966 } 2967 } 2968 fclose(fp); 2969 } 2970 } 2971 2972 // print a warning if any large page related flag is specified on command line 2973 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 2974 2975 const size_t default_page_size = (size_t)Linux::page_size(); 2976 if (_large_page_size > default_page_size) { 2977 _page_sizes[0] = _large_page_size; 2978 _page_sizes[1] = default_page_size; 2979 _page_sizes[2] = 0; 2980 } 2981 2982 UseHugeTLBFS = UseHugeTLBFS && 2983 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size); 2984 2985 if (UseHugeTLBFS) 2986 UseSHM = false; 2987 2988 UseLargePages = UseHugeTLBFS || UseSHM; 2989 2990 set_coredump_filter(); 2991 2992 // Large page support is available on 2.6 or newer kernel, some vendors 2993 // (e.g. Redhat) have backported it to their 2.4 based distributions. 2994 // We optimistically assume the support is available. If later it turns out 2995 // not true, VM will automatically switch to use regular page size. 2996 return true; 2997} 2998 2999#ifndef SHM_HUGETLB 3000#define SHM_HUGETLB 04000 3001#endif 3002 3003char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) { 3004 // "exec" is passed in but not used. Creating the shared image for 3005 // the code cache doesn't have an SHM_X executable permission to check. 3006 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3007 3008 key_t key = IPC_PRIVATE; 3009 char *addr; 3010 3011 bool warn_on_failure = UseLargePages && 3012 (!FLAG_IS_DEFAULT(UseLargePages) || 3013 !FLAG_IS_DEFAULT(LargePageSizeInBytes) 3014 ); 3015 char msg[128]; 3016 3017 // Create a large shared memory region to attach to based on size. 3018 // Currently, size is the total size of the heap 3019 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3020 if (shmid == -1) { 3021 // Possible reasons for shmget failure: 3022 // 1. shmmax is too small for Java heap. 3023 // > check shmmax value: cat /proc/sys/kernel/shmmax 3024 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3025 // 2. not enough large page memory. 3026 // > check available large pages: cat /proc/meminfo 3027 // > increase amount of large pages: 3028 // echo new_value > /proc/sys/vm/nr_hugepages 3029 // Note 1: different Linux may use different name for this property, 3030 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3031 // Note 2: it's possible there's enough physical memory available but 3032 // they are so fragmented after a long run that they can't 3033 // coalesce into large pages. Try to reserve large pages when 3034 // the system is still "fresh". 3035 if (warn_on_failure) { 3036 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3037 warning(msg); 3038 } 3039 return NULL; 3040 } 3041 3042 // attach to the region 3043 addr = (char*)shmat(shmid, req_addr, 0); 3044 int err = errno; 3045 3046 // Remove shmid. If shmat() is successful, the actual shared memory segment 3047 // will be deleted when it's detached by shmdt() or when the process 3048 // terminates. If shmat() is not successful this will remove the shared 3049 // segment immediately. 3050 shmctl(shmid, IPC_RMID, NULL); 3051 3052 if ((intptr_t)addr == -1) { 3053 if (warn_on_failure) { 3054 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3055 warning(msg); 3056 } 3057 return NULL; 3058 } 3059 3060 return addr; 3061} 3062 3063bool os::release_memory_special(char* base, size_t bytes) { 3064 // detaching the SHM segment will also delete it, see reserve_memory_special() 3065 int rslt = shmdt(base); 3066 return rslt == 0; 3067} 3068 3069size_t os::large_page_size() { 3070 return _large_page_size; 3071} 3072 3073// HugeTLBFS allows application to commit large page memory on demand; 3074// with SysV SHM the entire memory region must be allocated as shared 3075// memory. 3076bool os::can_commit_large_page_memory() { 3077 return UseHugeTLBFS; 3078} 3079 3080bool os::can_execute_large_page_memory() { 3081 return UseHugeTLBFS; 3082} 3083 3084// Reserve memory at an arbitrary address, only if that area is 3085// available (and not reserved for something else). 3086 3087char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3088 const int max_tries = 10; 3089 char* base[max_tries]; 3090 size_t size[max_tries]; 3091 const size_t gap = 0x000000; 3092 3093 // Assert only that the size is a multiple of the page size, since 3094 // that's all that mmap requires, and since that's all we really know 3095 // about at this low abstraction level. If we need higher alignment, 3096 // we can either pass an alignment to this method or verify alignment 3097 // in one of the methods further up the call chain. See bug 5044738. 3098 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3099 3100 // Repeatedly allocate blocks until the block is allocated at the 3101 // right spot. Give up after max_tries. Note that reserve_memory() will 3102 // automatically update _highest_vm_reserved_address if the call is 3103 // successful. The variable tracks the highest memory address every reserved 3104 // by JVM. It is used to detect heap-stack collision if running with 3105 // fixed-stack LinuxThreads. Because here we may attempt to reserve more 3106 // space than needed, it could confuse the collision detecting code. To 3107 // solve the problem, save current _highest_vm_reserved_address and 3108 // calculate the correct value before return. 3109 address old_highest = _highest_vm_reserved_address; 3110 3111 // Linux mmap allows caller to pass an address as hint; give it a try first, 3112 // if kernel honors the hint then we can return immediately. 3113 char * addr = anon_mmap(requested_addr, bytes, false); 3114 if (addr == requested_addr) { 3115 return requested_addr; 3116 } 3117 3118 if (addr != NULL) { 3119 // mmap() is successful but it fails to reserve at the requested address 3120 anon_munmap(addr, bytes); 3121 } 3122 3123 int i; 3124 for (i = 0; i < max_tries; ++i) { 3125 base[i] = reserve_memory(bytes); 3126 3127 if (base[i] != NULL) { 3128 // Is this the block we wanted? 3129 if (base[i] == requested_addr) { 3130 size[i] = bytes; 3131 break; 3132 } 3133 3134 // Does this overlap the block we wanted? Give back the overlapped 3135 // parts and try again. 3136 3137 size_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3138 if (top_overlap >= 0 && top_overlap < bytes) { 3139 unmap_memory(base[i], top_overlap); 3140 base[i] += top_overlap; 3141 size[i] = bytes - top_overlap; 3142 } else { 3143 size_t bottom_overlap = base[i] + bytes - requested_addr; 3144 if (bottom_overlap >= 0 && bottom_overlap < bytes) { 3145 unmap_memory(requested_addr, bottom_overlap); 3146 size[i] = bytes - bottom_overlap; 3147 } else { 3148 size[i] = bytes; 3149 } 3150 } 3151 } 3152 } 3153 3154 // Give back the unused reserved pieces. 3155 3156 for (int j = 0; j < i; ++j) { 3157 if (base[j] != NULL) { 3158 unmap_memory(base[j], size[j]); 3159 } 3160 } 3161 3162 if (i < max_tries) { 3163 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes); 3164 return requested_addr; 3165 } else { 3166 _highest_vm_reserved_address = old_highest; 3167 return NULL; 3168 } 3169} 3170 3171size_t os::read(int fd, void *buf, unsigned int nBytes) { 3172 return ::read(fd, buf, nBytes); 3173} 3174 3175// TODO-FIXME: reconcile Solaris' os::sleep with the linux variation. 3176// Solaris uses poll(), linux uses park(). 3177// Poll() is likely a better choice, assuming that Thread.interrupt() 3178// generates a SIGUSRx signal. Note that SIGUSR1 can interfere with 3179// SIGSEGV, see 4355769. 3180 3181const int NANOSECS_PER_MILLISECS = 1000000; 3182 3183int os::sleep(Thread* thread, jlong millis, bool interruptible) { 3184 assert(thread == Thread::current(), "thread consistency check"); 3185 3186 ParkEvent * const slp = thread->_SleepEvent ; 3187 slp->reset() ; 3188 OrderAccess::fence() ; 3189 3190 if (interruptible) { 3191 jlong prevtime = javaTimeNanos(); 3192 3193 for (;;) { 3194 if (os::is_interrupted(thread, true)) { 3195 return OS_INTRPT; 3196 } 3197 3198 jlong newtime = javaTimeNanos(); 3199 3200 if (newtime - prevtime < 0) { 3201 // time moving backwards, should only happen if no monotonic clock 3202 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3203 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3204 } else { 3205 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS; 3206 } 3207 3208 if(millis <= 0) { 3209 return OS_OK; 3210 } 3211 3212 prevtime = newtime; 3213 3214 { 3215 assert(thread->is_Java_thread(), "sanity check"); 3216 JavaThread *jt = (JavaThread *) thread; 3217 ThreadBlockInVM tbivm(jt); 3218 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 3219 3220 jt->set_suspend_equivalent(); 3221 // cleared by handle_special_suspend_equivalent_condition() or 3222 // java_suspend_self() via check_and_wait_while_suspended() 3223 3224 slp->park(millis); 3225 3226 // were we externally suspended while we were waiting? 3227 jt->check_and_wait_while_suspended(); 3228 } 3229 } 3230 } else { 3231 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 3232 jlong prevtime = javaTimeNanos(); 3233 3234 for (;;) { 3235 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 3236 // the 1st iteration ... 3237 jlong newtime = javaTimeNanos(); 3238 3239 if (newtime - prevtime < 0) { 3240 // time moving backwards, should only happen if no monotonic clock 3241 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3242 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3243 } else { 3244 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS; 3245 } 3246 3247 if(millis <= 0) break ; 3248 3249 prevtime = newtime; 3250 slp->park(millis); 3251 } 3252 return OS_OK ; 3253 } 3254} 3255 3256int os::naked_sleep() { 3257 // %% make the sleep time an integer flag. for now use 1 millisec. 3258 return os::sleep(Thread::current(), 1, false); 3259} 3260 3261// Sleep forever; naked call to OS-specific sleep; use with CAUTION 3262void os::infinite_sleep() { 3263 while (true) { // sleep forever ... 3264 ::sleep(100); // ... 100 seconds at a time 3265 } 3266} 3267 3268// Used to convert frequent JVM_Yield() to nops 3269bool os::dont_yield() { 3270 return DontYieldALot; 3271} 3272 3273void os::yield() { 3274 sched_yield(); 3275} 3276 3277os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;} 3278 3279void os::yield_all(int attempts) { 3280 // Yields to all threads, including threads with lower priorities 3281 // Threads on Linux are all with same priority. The Solaris style 3282 // os::yield_all() with nanosleep(1ms) is not necessary. 3283 sched_yield(); 3284} 3285 3286// Called from the tight loops to possibly influence time-sharing heuristics 3287void os::loop_breaker(int attempts) { 3288 os::yield_all(attempts); 3289} 3290 3291//////////////////////////////////////////////////////////////////////////////// 3292// thread priority support 3293 3294// Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3295// only supports dynamic priority, static priority must be zero. For real-time 3296// applications, Linux supports SCHED_RR which allows static priority (1-99). 3297// However, for large multi-threaded applications, SCHED_RR is not only slower 3298// than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3299// of 5 runs - Sep 2005). 3300// 3301// The following code actually changes the niceness of kernel-thread/LWP. It 3302// has an assumption that setpriority() only modifies one kernel-thread/LWP, 3303// not the entire user process, and user level threads are 1:1 mapped to kernel 3304// threads. It has always been the case, but could change in the future. For 3305// this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3306// It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3307 3308int os::java_to_os_priority[MaxPriority + 1] = { 3309 19, // 0 Entry should never be used 3310 3311 4, // 1 MinPriority 3312 3, // 2 3313 2, // 3 3314 3315 1, // 4 3316 0, // 5 NormPriority 3317 -1, // 6 3318 3319 -2, // 7 3320 -3, // 8 3321 -4, // 9 NearMaxPriority 3322 3323 -5 // 10 MaxPriority 3324}; 3325 3326static int prio_init() { 3327 if (ThreadPriorityPolicy == 1) { 3328 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3329 // if effective uid is not root. Perhaps, a more elegant way of doing 3330 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3331 if (geteuid() != 0) { 3332 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3333 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3334 } 3335 ThreadPriorityPolicy = 0; 3336 } 3337 } 3338 return 0; 3339} 3340 3341OSReturn os::set_native_priority(Thread* thread, int newpri) { 3342 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK; 3343 3344 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3345 return (ret == 0) ? OS_OK : OS_ERR; 3346} 3347 3348OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) { 3349 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) { 3350 *priority_ptr = java_to_os_priority[NormPriority]; 3351 return OS_OK; 3352 } 3353 3354 errno = 0; 3355 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3356 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3357} 3358 3359// Hint to the underlying OS that a task switch would not be good. 3360// Void return because it's a hint and can fail. 3361void os::hint_no_preempt() {} 3362 3363//////////////////////////////////////////////////////////////////////////////// 3364// suspend/resume support 3365 3366// the low-level signal-based suspend/resume support is a remnant from the 3367// old VM-suspension that used to be for java-suspension, safepoints etc, 3368// within hotspot. Now there is a single use-case for this: 3369// - calling get_thread_pc() on the VMThread by the flat-profiler task 3370// that runs in the watcher thread. 3371// The remaining code is greatly simplified from the more general suspension 3372// code that used to be used. 3373// 3374// The protocol is quite simple: 3375// - suspend: 3376// - sends a signal to the target thread 3377// - polls the suspend state of the osthread using a yield loop 3378// - target thread signal handler (SR_handler) sets suspend state 3379// and blocks in sigsuspend until continued 3380// - resume: 3381// - sets target osthread state to continue 3382// - sends signal to end the sigsuspend loop in the SR_handler 3383// 3384// Note that the SR_lock plays no role in this suspend/resume protocol. 3385// 3386 3387static void resume_clear_context(OSThread *osthread) { 3388 osthread->set_ucontext(NULL); 3389 osthread->set_siginfo(NULL); 3390 3391 // notify the suspend action is completed, we have now resumed 3392 osthread->sr.clear_suspended(); 3393} 3394 3395static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) { 3396 osthread->set_ucontext(context); 3397 osthread->set_siginfo(siginfo); 3398} 3399 3400// 3401// Handler function invoked when a thread's execution is suspended or 3402// resumed. We have to be careful that only async-safe functions are 3403// called here (Note: most pthread functions are not async safe and 3404// should be avoided.) 3405// 3406// Note: sigwait() is a more natural fit than sigsuspend() from an 3407// interface point of view, but sigwait() prevents the signal hander 3408// from being run. libpthread would get very confused by not having 3409// its signal handlers run and prevents sigwait()'s use with the 3410// mutex granting granting signal. 3411// 3412// Currently only ever called on the VMThread 3413// 3414static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3415 // Save and restore errno to avoid confusing native code with EINTR 3416 // after sigsuspend. 3417 int old_errno = errno; 3418 3419 Thread* thread = Thread::current(); 3420 OSThread* osthread = thread->osthread(); 3421 assert(thread->is_VM_thread(), "Must be VMThread"); 3422 // read current suspend action 3423 int action = osthread->sr.suspend_action(); 3424 if (action == SR_SUSPEND) { 3425 suspend_save_context(osthread, siginfo, context); 3426 3427 // Notify the suspend action is about to be completed. do_suspend() 3428 // waits until SR_SUSPENDED is set and then returns. We will wait 3429 // here for a resume signal and that completes the suspend-other 3430 // action. do_suspend/do_resume is always called as a pair from 3431 // the same thread - so there are no races 3432 3433 // notify the caller 3434 osthread->sr.set_suspended(); 3435 3436 sigset_t suspend_set; // signals for sigsuspend() 3437 3438 // get current set of blocked signals and unblock resume signal 3439 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3440 sigdelset(&suspend_set, SR_signum); 3441 3442 // wait here until we are resumed 3443 do { 3444 sigsuspend(&suspend_set); 3445 // ignore all returns until we get a resume signal 3446 } while (osthread->sr.suspend_action() != SR_CONTINUE); 3447 3448 resume_clear_context(osthread); 3449 3450 } else { 3451 assert(action == SR_CONTINUE, "unexpected sr action"); 3452 // nothing special to do - just leave the handler 3453 } 3454 3455 errno = old_errno; 3456} 3457 3458 3459static int SR_initialize() { 3460 struct sigaction act; 3461 char *s; 3462 /* Get signal number to use for suspend/resume */ 3463 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3464 int sig = ::strtol(s, 0, 10); 3465 if (sig > 0 || sig < _NSIG) { 3466 SR_signum = sig; 3467 } 3468 } 3469 3470 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 3471 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 3472 3473 sigemptyset(&SR_sigset); 3474 sigaddset(&SR_sigset, SR_signum); 3475 3476 /* Set up signal handler for suspend/resume */ 3477 act.sa_flags = SA_RESTART|SA_SIGINFO; 3478 act.sa_handler = (void (*)(int)) SR_handler; 3479 3480 // SR_signum is blocked by default. 3481 // 4528190 - We also need to block pthread restart signal (32 on all 3482 // supported Linux platforms). Note that LinuxThreads need to block 3483 // this signal for all threads to work properly. So we don't have 3484 // to use hard-coded signal number when setting up the mask. 3485 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 3486 3487 if (sigaction(SR_signum, &act, 0) == -1) { 3488 return -1; 3489 } 3490 3491 // Save signal flag 3492 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 3493 return 0; 3494} 3495 3496static int SR_finalize() { 3497 return 0; 3498} 3499 3500 3501// returns true on success and false on error - really an error is fatal 3502// but this seems the normal response to library errors 3503static bool do_suspend(OSThread* osthread) { 3504 // mark as suspended and send signal 3505 osthread->sr.set_suspend_action(SR_SUSPEND); 3506 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3507 assert_status(status == 0, status, "pthread_kill"); 3508 3509 // check status and wait until notified of suspension 3510 if (status == 0) { 3511 for (int i = 0; !osthread->sr.is_suspended(); i++) { 3512 os::yield_all(i); 3513 } 3514 osthread->sr.set_suspend_action(SR_NONE); 3515 return true; 3516 } 3517 else { 3518 osthread->sr.set_suspend_action(SR_NONE); 3519 return false; 3520 } 3521} 3522 3523static void do_resume(OSThread* osthread) { 3524 assert(osthread->sr.is_suspended(), "thread should be suspended"); 3525 osthread->sr.set_suspend_action(SR_CONTINUE); 3526 3527 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3528 assert_status(status == 0, status, "pthread_kill"); 3529 // check status and wait unit notified of resumption 3530 if (status == 0) { 3531 for (int i = 0; osthread->sr.is_suspended(); i++) { 3532 os::yield_all(i); 3533 } 3534 } 3535 osthread->sr.set_suspend_action(SR_NONE); 3536} 3537 3538//////////////////////////////////////////////////////////////////////////////// 3539// interrupt support 3540 3541void os::interrupt(Thread* thread) { 3542 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3543 "possibility of dangling Thread pointer"); 3544 3545 OSThread* osthread = thread->osthread(); 3546 3547 if (!osthread->interrupted()) { 3548 osthread->set_interrupted(true); 3549 // More than one thread can get here with the same value of osthread, 3550 // resulting in multiple notifications. We do, however, want the store 3551 // to interrupted() to be visible to other threads before we execute unpark(). 3552 OrderAccess::fence(); 3553 ParkEvent * const slp = thread->_SleepEvent ; 3554 if (slp != NULL) slp->unpark() ; 3555 } 3556 3557 // For JSR166. Unpark even if interrupt status already was set 3558 if (thread->is_Java_thread()) 3559 ((JavaThread*)thread)->parker()->unpark(); 3560 3561 ParkEvent * ev = thread->_ParkEvent ; 3562 if (ev != NULL) ev->unpark() ; 3563 3564} 3565 3566bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 3567 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3568 "possibility of dangling Thread pointer"); 3569 3570 OSThread* osthread = thread->osthread(); 3571 3572 bool interrupted = osthread->interrupted(); 3573 3574 if (interrupted && clear_interrupted) { 3575 osthread->set_interrupted(false); 3576 // consider thread->_SleepEvent->reset() ... optional optimization 3577 } 3578 3579 return interrupted; 3580} 3581 3582/////////////////////////////////////////////////////////////////////////////////// 3583// signal handling (except suspend/resume) 3584 3585// This routine may be used by user applications as a "hook" to catch signals. 3586// The user-defined signal handler must pass unrecognized signals to this 3587// routine, and if it returns true (non-zero), then the signal handler must 3588// return immediately. If the flag "abort_if_unrecognized" is true, then this 3589// routine will never retun false (zero), but instead will execute a VM panic 3590// routine kill the process. 3591// 3592// If this routine returns false, it is OK to call it again. This allows 3593// the user-defined signal handler to perform checks either before or after 3594// the VM performs its own checks. Naturally, the user code would be making 3595// a serious error if it tried to handle an exception (such as a null check 3596// or breakpoint) that the VM was generating for its own correct operation. 3597// 3598// This routine may recognize any of the following kinds of signals: 3599// SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 3600// It should be consulted by handlers for any of those signals. 3601// 3602// The caller of this routine must pass in the three arguments supplied 3603// to the function referred to in the "sa_sigaction" (not the "sa_handler") 3604// field of the structure passed to sigaction(). This routine assumes that 3605// the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 3606// 3607// Note that the VM will print warnings if it detects conflicting signal 3608// handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 3609// 3610extern "C" JNIEXPORT int 3611JVM_handle_linux_signal(int signo, siginfo_t* siginfo, 3612 void* ucontext, int abort_if_unrecognized); 3613 3614void signalHandler(int sig, siginfo_t* info, void* uc) { 3615 assert(info != NULL && uc != NULL, "it must be old kernel"); 3616 JVM_handle_linux_signal(sig, info, uc, true); 3617} 3618 3619 3620// This boolean allows users to forward their own non-matching signals 3621// to JVM_handle_linux_signal, harmlessly. 3622bool os::Linux::signal_handlers_are_installed = false; 3623 3624// For signal-chaining 3625struct sigaction os::Linux::sigact[MAXSIGNUM]; 3626unsigned int os::Linux::sigs = 0; 3627bool os::Linux::libjsig_is_loaded = false; 3628typedef struct sigaction *(*get_signal_t)(int); 3629get_signal_t os::Linux::get_signal_action = NULL; 3630 3631struct sigaction* os::Linux::get_chained_signal_action(int sig) { 3632 struct sigaction *actp = NULL; 3633 3634 if (libjsig_is_loaded) { 3635 // Retrieve the old signal handler from libjsig 3636 actp = (*get_signal_action)(sig); 3637 } 3638 if (actp == NULL) { 3639 // Retrieve the preinstalled signal handler from jvm 3640 actp = get_preinstalled_handler(sig); 3641 } 3642 3643 return actp; 3644} 3645 3646static bool call_chained_handler(struct sigaction *actp, int sig, 3647 siginfo_t *siginfo, void *context) { 3648 // Call the old signal handler 3649 if (actp->sa_handler == SIG_DFL) { 3650 // It's more reasonable to let jvm treat it as an unexpected exception 3651 // instead of taking the default action. 3652 return false; 3653 } else if (actp->sa_handler != SIG_IGN) { 3654 if ((actp->sa_flags & SA_NODEFER) == 0) { 3655 // automaticlly block the signal 3656 sigaddset(&(actp->sa_mask), sig); 3657 } 3658 3659 sa_handler_t hand; 3660 sa_sigaction_t sa; 3661 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 3662 // retrieve the chained handler 3663 if (siginfo_flag_set) { 3664 sa = actp->sa_sigaction; 3665 } else { 3666 hand = actp->sa_handler; 3667 } 3668 3669 if ((actp->sa_flags & SA_RESETHAND) != 0) { 3670 actp->sa_handler = SIG_DFL; 3671 } 3672 3673 // try to honor the signal mask 3674 sigset_t oset; 3675 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 3676 3677 // call into the chained handler 3678 if (siginfo_flag_set) { 3679 (*sa)(sig, siginfo, context); 3680 } else { 3681 (*hand)(sig); 3682 } 3683 3684 // restore the signal mask 3685 pthread_sigmask(SIG_SETMASK, &oset, 0); 3686 } 3687 // Tell jvm's signal handler the signal is taken care of. 3688 return true; 3689} 3690 3691bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 3692 bool chained = false; 3693 // signal-chaining 3694 if (UseSignalChaining) { 3695 struct sigaction *actp = get_chained_signal_action(sig); 3696 if (actp != NULL) { 3697 chained = call_chained_handler(actp, sig, siginfo, context); 3698 } 3699 } 3700 return chained; 3701} 3702 3703struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 3704 if ((( (unsigned int)1 << sig ) & sigs) != 0) { 3705 return &sigact[sig]; 3706 } 3707 return NULL; 3708} 3709 3710void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 3711 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3712 sigact[sig] = oldAct; 3713 sigs |= (unsigned int)1 << sig; 3714} 3715 3716// for diagnostic 3717int os::Linux::sigflags[MAXSIGNUM]; 3718 3719int os::Linux::get_our_sigflags(int sig) { 3720 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3721 return sigflags[sig]; 3722} 3723 3724void os::Linux::set_our_sigflags(int sig, int flags) { 3725 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3726 sigflags[sig] = flags; 3727} 3728 3729void os::Linux::set_signal_handler(int sig, bool set_installed) { 3730 // Check for overwrite. 3731 struct sigaction oldAct; 3732 sigaction(sig, (struct sigaction*)NULL, &oldAct); 3733 3734 void* oldhand = oldAct.sa_sigaction 3735 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3736 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3737 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 3738 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 3739 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 3740 if (AllowUserSignalHandlers || !set_installed) { 3741 // Do not overwrite; user takes responsibility to forward to us. 3742 return; 3743 } else if (UseSignalChaining) { 3744 // save the old handler in jvm 3745 save_preinstalled_handler(sig, oldAct); 3746 // libjsig also interposes the sigaction() call below and saves the 3747 // old sigaction on it own. 3748 } else { 3749 fatal(err_msg("Encountered unexpected pre-existing sigaction handler " 3750 "%#lx for signal %d.", (long)oldhand, sig)); 3751 } 3752 } 3753 3754 struct sigaction sigAct; 3755 sigfillset(&(sigAct.sa_mask)); 3756 sigAct.sa_handler = SIG_DFL; 3757 if (!set_installed) { 3758 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3759 } else { 3760 sigAct.sa_sigaction = signalHandler; 3761 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3762 } 3763 // Save flags, which are set by ours 3764 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3765 sigflags[sig] = sigAct.sa_flags; 3766 3767 int ret = sigaction(sig, &sigAct, &oldAct); 3768 assert(ret == 0, "check"); 3769 3770 void* oldhand2 = oldAct.sa_sigaction 3771 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3772 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3773 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 3774} 3775 3776// install signal handlers for signals that HotSpot needs to 3777// handle in order to support Java-level exception handling. 3778 3779void os::Linux::install_signal_handlers() { 3780 if (!signal_handlers_are_installed) { 3781 signal_handlers_are_installed = true; 3782 3783 // signal-chaining 3784 typedef void (*signal_setting_t)(); 3785 signal_setting_t begin_signal_setting = NULL; 3786 signal_setting_t end_signal_setting = NULL; 3787 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3788 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 3789 if (begin_signal_setting != NULL) { 3790 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3791 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 3792 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 3793 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 3794 libjsig_is_loaded = true; 3795 assert(UseSignalChaining, "should enable signal-chaining"); 3796 } 3797 if (libjsig_is_loaded) { 3798 // Tell libjsig jvm is setting signal handlers 3799 (*begin_signal_setting)(); 3800 } 3801 3802 set_signal_handler(SIGSEGV, true); 3803 set_signal_handler(SIGPIPE, true); 3804 set_signal_handler(SIGBUS, true); 3805 set_signal_handler(SIGILL, true); 3806 set_signal_handler(SIGFPE, true); 3807 set_signal_handler(SIGXFSZ, true); 3808 3809 if (libjsig_is_loaded) { 3810 // Tell libjsig jvm finishes setting signal handlers 3811 (*end_signal_setting)(); 3812 } 3813 3814 // We don't activate signal checker if libjsig is in place, we trust ourselves 3815 // and if UserSignalHandler is installed all bets are off 3816 if (CheckJNICalls) { 3817 if (libjsig_is_loaded) { 3818 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 3819 check_signals = false; 3820 } 3821 if (AllowUserSignalHandlers) { 3822 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 3823 check_signals = false; 3824 } 3825 } 3826 } 3827} 3828 3829// This is the fastest way to get thread cpu time on Linux. 3830// Returns cpu time (user+sys) for any thread, not only for current. 3831// POSIX compliant clocks are implemented in the kernels 2.6.16+. 3832// It might work on 2.6.10+ with a special kernel/glibc patch. 3833// For reference, please, see IEEE Std 1003.1-2004: 3834// http://www.unix.org/single_unix_specification 3835 3836jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 3837 struct timespec tp; 3838 int rc = os::Linux::clock_gettime(clockid, &tp); 3839 assert(rc == 0, "clock_gettime is expected to return 0 code"); 3840 3841 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec; 3842} 3843 3844///// 3845// glibc on Linux platform uses non-documented flag 3846// to indicate, that some special sort of signal 3847// trampoline is used. 3848// We will never set this flag, and we should 3849// ignore this flag in our diagnostic 3850#ifdef SIGNIFICANT_SIGNAL_MASK 3851#undef SIGNIFICANT_SIGNAL_MASK 3852#endif 3853#define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 3854 3855static const char* get_signal_handler_name(address handler, 3856 char* buf, int buflen) { 3857 int offset; 3858 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 3859 if (found) { 3860 // skip directory names 3861 const char *p1, *p2; 3862 p1 = buf; 3863 size_t len = strlen(os::file_separator()); 3864 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 3865 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 3866 } else { 3867 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 3868 } 3869 return buf; 3870} 3871 3872static void print_signal_handler(outputStream* st, int sig, 3873 char* buf, size_t buflen) { 3874 struct sigaction sa; 3875 3876 sigaction(sig, NULL, &sa); 3877 3878 // See comment for SIGNIFICANT_SIGNAL_MASK define 3879 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3880 3881 st->print("%s: ", os::exception_name(sig, buf, buflen)); 3882 3883 address handler = (sa.sa_flags & SA_SIGINFO) 3884 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 3885 : CAST_FROM_FN_PTR(address, sa.sa_handler); 3886 3887 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 3888 st->print("SIG_DFL"); 3889 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 3890 st->print("SIG_IGN"); 3891 } else { 3892 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 3893 } 3894 3895 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask); 3896 3897 address rh = VMError::get_resetted_sighandler(sig); 3898 // May be, handler was resetted by VMError? 3899 if(rh != NULL) { 3900 handler = rh; 3901 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 3902 } 3903 3904 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags); 3905 3906 // Check: is it our handler? 3907 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 3908 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 3909 // It is our signal handler 3910 // check for flags, reset system-used one! 3911 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 3912 st->print( 3913 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 3914 os::Linux::get_our_sigflags(sig)); 3915 } 3916 } 3917 st->cr(); 3918} 3919 3920 3921#define DO_SIGNAL_CHECK(sig) \ 3922 if (!sigismember(&check_signal_done, sig)) \ 3923 os::Linux::check_signal_handler(sig) 3924 3925// This method is a periodic task to check for misbehaving JNI applications 3926// under CheckJNI, we can add any periodic checks here 3927 3928void os::run_periodic_checks() { 3929 3930 if (check_signals == false) return; 3931 3932 // SEGV and BUS if overridden could potentially prevent 3933 // generation of hs*.log in the event of a crash, debugging 3934 // such a case can be very challenging, so we absolutely 3935 // check the following for a good measure: 3936 DO_SIGNAL_CHECK(SIGSEGV); 3937 DO_SIGNAL_CHECK(SIGILL); 3938 DO_SIGNAL_CHECK(SIGFPE); 3939 DO_SIGNAL_CHECK(SIGBUS); 3940 DO_SIGNAL_CHECK(SIGPIPE); 3941 DO_SIGNAL_CHECK(SIGXFSZ); 3942 3943 3944 // ReduceSignalUsage allows the user to override these handlers 3945 // see comments at the very top and jvm_solaris.h 3946 if (!ReduceSignalUsage) { 3947 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 3948 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 3949 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 3950 DO_SIGNAL_CHECK(BREAK_SIGNAL); 3951 } 3952 3953 DO_SIGNAL_CHECK(SR_signum); 3954 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 3955} 3956 3957typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 3958 3959static os_sigaction_t os_sigaction = NULL; 3960 3961void os::Linux::check_signal_handler(int sig) { 3962 char buf[O_BUFLEN]; 3963 address jvmHandler = NULL; 3964 3965 3966 struct sigaction act; 3967 if (os_sigaction == NULL) { 3968 // only trust the default sigaction, in case it has been interposed 3969 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 3970 if (os_sigaction == NULL) return; 3971 } 3972 3973 os_sigaction(sig, (struct sigaction*)NULL, &act); 3974 3975 3976 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3977 3978 address thisHandler = (act.sa_flags & SA_SIGINFO) 3979 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 3980 : CAST_FROM_FN_PTR(address, act.sa_handler) ; 3981 3982 3983 switch(sig) { 3984 case SIGSEGV: 3985 case SIGBUS: 3986 case SIGFPE: 3987 case SIGPIPE: 3988 case SIGILL: 3989 case SIGXFSZ: 3990 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 3991 break; 3992 3993 case SHUTDOWN1_SIGNAL: 3994 case SHUTDOWN2_SIGNAL: 3995 case SHUTDOWN3_SIGNAL: 3996 case BREAK_SIGNAL: 3997 jvmHandler = (address)user_handler(); 3998 break; 3999 4000 case INTERRUPT_SIGNAL: 4001 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 4002 break; 4003 4004 default: 4005 if (sig == SR_signum) { 4006 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4007 } else { 4008 return; 4009 } 4010 break; 4011 } 4012 4013 if (thisHandler != jvmHandler) { 4014 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4015 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4016 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4017 // No need to check this sig any longer 4018 sigaddset(&check_signal_done, sig); 4019 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4020 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4021 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 4022 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 4023 // No need to check this sig any longer 4024 sigaddset(&check_signal_done, sig); 4025 } 4026 4027 // Dump all the signal 4028 if (sigismember(&check_signal_done, sig)) { 4029 print_signal_handlers(tty, buf, O_BUFLEN); 4030 } 4031} 4032 4033extern void report_error(char* file_name, int line_no, char* title, char* format, ...); 4034 4035extern bool signal_name(int signo, char* buf, size_t len); 4036 4037const char* os::exception_name(int exception_code, char* buf, size_t size) { 4038 if (0 < exception_code && exception_code <= SIGRTMAX) { 4039 // signal 4040 if (!signal_name(exception_code, buf, size)) { 4041 jio_snprintf(buf, size, "SIG%d", exception_code); 4042 } 4043 return buf; 4044 } else { 4045 return NULL; 4046 } 4047} 4048 4049// this is called _before_ the most of global arguments have been parsed 4050void os::init(void) { 4051 char dummy; /* used to get a guess on initial stack address */ 4052// first_hrtime = gethrtime(); 4053 4054 // With LinuxThreads the JavaMain thread pid (primordial thread) 4055 // is different than the pid of the java launcher thread. 4056 // So, on Linux, the launcher thread pid is passed to the VM 4057 // via the sun.java.launcher.pid property. 4058 // Use this property instead of getpid() if it was correctly passed. 4059 // See bug 6351349. 4060 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid(); 4061 4062 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid(); 4063 4064 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4065 4066 init_random(1234567); 4067 4068 ThreadCritical::initialize(); 4069 4070 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4071 if (Linux::page_size() == -1) { 4072 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)", 4073 strerror(errno))); 4074 } 4075 init_page_sizes((size_t) Linux::page_size()); 4076 4077 Linux::initialize_system_info(); 4078 4079 // main_thread points to the aboriginal thread 4080 Linux::_main_thread = pthread_self(); 4081 4082 Linux::clock_init(); 4083 initial_time_count = os::elapsed_counter(); 4084 pthread_mutex_init(&dl_mutex, NULL); 4085} 4086 4087// To install functions for atexit system call 4088extern "C" { 4089 static void perfMemory_exit_helper() { 4090 perfMemory_exit(); 4091 } 4092} 4093 4094// this is called _after_ the global arguments have been parsed 4095jint os::init_2(void) 4096{ 4097 Linux::fast_thread_clock_init(); 4098 4099 // Allocate a single page and mark it as readable for safepoint polling 4100 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4101 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" ); 4102 4103 os::set_polling_page( polling_page ); 4104 4105#ifndef PRODUCT 4106 if(Verbose && PrintMiscellaneous) 4107 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page); 4108#endif 4109 4110 if (!UseMembar) { 4111 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4112 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page"); 4113 os::set_memory_serialize_page( mem_serialize_page ); 4114 4115#ifndef PRODUCT 4116 if(Verbose && PrintMiscellaneous) 4117 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page); 4118#endif 4119 } 4120 4121 FLAG_SET_DEFAULT(UseLargePages, os::large_page_init()); 4122 4123 // initialize suspend/resume support - must do this before signal_sets_init() 4124 if (SR_initialize() != 0) { 4125 perror("SR_initialize failed"); 4126 return JNI_ERR; 4127 } 4128 4129 Linux::signal_sets_init(); 4130 Linux::install_signal_handlers(); 4131 4132 // Check minimum allowable stack size for thread creation and to initialize 4133 // the java system classes, including StackOverflowError - depends on page 4134 // size. Add a page for compiler2 recursion in main thread. 4135 // Add in 2*BytesPerWord times page size to account for VM stack during 4136 // class initialization depending on 32 or 64 bit VM. 4137 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4138 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+ 4139 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size()); 4140 4141 size_t threadStackSizeInBytes = ThreadStackSize * K; 4142 if (threadStackSizeInBytes != 0 && 4143 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4144 tty->print_cr("\nThe stack size specified is too small, " 4145 "Specify at least %dk", 4146 os::Linux::min_stack_allowed/ K); 4147 return JNI_ERR; 4148 } 4149 4150 // Make the stack size a multiple of the page size so that 4151 // the yellow/red zones can be guarded. 4152 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4153 vm_page_size())); 4154 4155 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4156 4157 Linux::libpthread_init(); 4158 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4159 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n", 4160 Linux::glibc_version(), Linux::libpthread_version(), 4161 Linux::is_floating_stack() ? "floating stack" : "fixed stack"); 4162 } 4163 4164 if (UseNUMA) { 4165 if (!Linux::libnuma_init()) { 4166 UseNUMA = false; 4167 } else { 4168 if ((Linux::numa_max_node() < 1)) { 4169 // There's only one node(they start from 0), disable NUMA. 4170 UseNUMA = false; 4171 } 4172 } 4173 if (!UseNUMA && ForceNUMA) { 4174 UseNUMA = true; 4175 } 4176 } 4177 4178 if (MaxFDLimit) { 4179 // set the number of file descriptors to max. print out error 4180 // if getrlimit/setrlimit fails but continue regardless. 4181 struct rlimit nbr_files; 4182 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4183 if (status != 0) { 4184 if (PrintMiscellaneous && (Verbose || WizardMode)) 4185 perror("os::init_2 getrlimit failed"); 4186 } else { 4187 nbr_files.rlim_cur = nbr_files.rlim_max; 4188 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4189 if (status != 0) { 4190 if (PrintMiscellaneous && (Verbose || WizardMode)) 4191 perror("os::init_2 setrlimit failed"); 4192 } 4193 } 4194 } 4195 4196 // Initialize lock used to serialize thread creation (see os::create_thread) 4197 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4198 4199 // at-exit methods are called in the reverse order of their registration. 4200 // atexit functions are called on return from main or as a result of a 4201 // call to exit(3C). There can be only 32 of these functions registered 4202 // and atexit() does not set errno. 4203 4204 if (PerfAllowAtExitRegistration) { 4205 // only register atexit functions if PerfAllowAtExitRegistration is set. 4206 // atexit functions can be delayed until process exit time, which 4207 // can be problematic for embedded VM situations. Embedded VMs should 4208 // call DestroyJavaVM() to assure that VM resources are released. 4209 4210 // note: perfMemory_exit_helper atexit function may be removed in 4211 // the future if the appropriate cleanup code can be added to the 4212 // VM_Exit VMOperation's doit method. 4213 if (atexit(perfMemory_exit_helper) != 0) { 4214 warning("os::init2 atexit(perfMemory_exit_helper) failed"); 4215 } 4216 } 4217 4218 // initialize thread priority policy 4219 prio_init(); 4220 4221 return JNI_OK; 4222} 4223 4224// this is called at the end of vm_initialization 4225void os::init_3(void) { } 4226 4227// Mark the polling page as unreadable 4228void os::make_polling_page_unreadable(void) { 4229 if( !guard_memory((char*)_polling_page, Linux::page_size()) ) 4230 fatal("Could not disable polling page"); 4231}; 4232 4233// Mark the polling page as readable 4234void os::make_polling_page_readable(void) { 4235 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4236 fatal("Could not enable polling page"); 4237 } 4238}; 4239 4240int os::active_processor_count() { 4241 // Linux doesn't yet have a (official) notion of processor sets, 4242 // so just return the number of online processors. 4243 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4244 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4245 return online_cpus; 4246} 4247 4248bool os::distribute_processes(uint length, uint* distribution) { 4249 // Not yet implemented. 4250 return false; 4251} 4252 4253bool os::bind_to_processor(uint processor_id) { 4254 // Not yet implemented. 4255 return false; 4256} 4257 4258/// 4259 4260// Suspends the target using the signal mechanism and then grabs the PC before 4261// resuming the target. Used by the flat-profiler only 4262ExtendedPC os::get_thread_pc(Thread* thread) { 4263 // Make sure that it is called by the watcher for the VMThread 4264 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4265 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4266 4267 ExtendedPC epc; 4268 4269 OSThread* osthread = thread->osthread(); 4270 if (do_suspend(osthread)) { 4271 if (osthread->ucontext() != NULL) { 4272 epc = os::Linux::ucontext_get_pc(osthread->ucontext()); 4273 } else { 4274 // NULL context is unexpected, double-check this is the VMThread 4275 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4276 } 4277 do_resume(osthread); 4278 } 4279 // failure means pthread_kill failed for some reason - arguably this is 4280 // a fatal problem, but such problems are ignored elsewhere 4281 4282 return epc; 4283} 4284 4285int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime) 4286{ 4287 if (is_NPTL()) { 4288 return pthread_cond_timedwait(_cond, _mutex, _abstime); 4289 } else { 4290#ifndef IA64 4291 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control 4292 // word back to default 64bit precision if condvar is signaled. Java 4293 // wants 53bit precision. Save and restore current value. 4294 int fpu = get_fpu_control_word(); 4295#endif // IA64 4296 int status = pthread_cond_timedwait(_cond, _mutex, _abstime); 4297#ifndef IA64 4298 set_fpu_control_word(fpu); 4299#endif // IA64 4300 return status; 4301 } 4302} 4303 4304//////////////////////////////////////////////////////////////////////////////// 4305// debug support 4306 4307static address same_page(address x, address y) { 4308 int page_bits = -os::vm_page_size(); 4309 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits)) 4310 return x; 4311 else if (x > y) 4312 return (address)(intptr_t(y) | ~page_bits) + 1; 4313 else 4314 return (address)(intptr_t(y) & page_bits); 4315} 4316 4317bool os::find(address addr, outputStream* st) { 4318 Dl_info dlinfo; 4319 memset(&dlinfo, 0, sizeof(dlinfo)); 4320 if (dladdr(addr, &dlinfo)) { 4321 st->print(PTR_FORMAT ": ", addr); 4322 if (dlinfo.dli_sname != NULL) { 4323 st->print("%s+%#x", dlinfo.dli_sname, 4324 addr - (intptr_t)dlinfo.dli_saddr); 4325 } else if (dlinfo.dli_fname) { 4326 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 4327 } else { 4328 st->print("<absolute address>"); 4329 } 4330 if (dlinfo.dli_fname) { 4331 st->print(" in %s", dlinfo.dli_fname); 4332 } 4333 if (dlinfo.dli_fbase) { 4334 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 4335 } 4336 st->cr(); 4337 4338 if (Verbose) { 4339 // decode some bytes around the PC 4340 address begin = same_page(addr-40, addr); 4341 address end = same_page(addr+40, addr); 4342 address lowest = (address) dlinfo.dli_sname; 4343 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4344 if (begin < lowest) begin = lowest; 4345 Dl_info dlinfo2; 4346 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr 4347 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) 4348 end = (address) dlinfo2.dli_saddr; 4349 Disassembler::decode(begin, end, st); 4350 } 4351 return true; 4352 } 4353 return false; 4354} 4355 4356//////////////////////////////////////////////////////////////////////////////// 4357// misc 4358 4359// This does not do anything on Linux. This is basically a hook for being 4360// able to use structured exception handling (thread-local exception filters) 4361// on, e.g., Win32. 4362void 4363os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 4364 JavaCallArguments* args, Thread* thread) { 4365 f(value, method, args, thread); 4366} 4367 4368void os::print_statistics() { 4369} 4370 4371int os::message_box(const char* title, const char* message) { 4372 int i; 4373 fdStream err(defaultStream::error_fd()); 4374 for (i = 0; i < 78; i++) err.print_raw("="); 4375 err.cr(); 4376 err.print_raw_cr(title); 4377 for (i = 0; i < 78; i++) err.print_raw("-"); 4378 err.cr(); 4379 err.print_raw_cr(message); 4380 for (i = 0; i < 78; i++) err.print_raw("="); 4381 err.cr(); 4382 4383 char buf[16]; 4384 // Prevent process from exiting upon "read error" without consuming all CPU 4385 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4386 4387 return buf[0] == 'y' || buf[0] == 'Y'; 4388} 4389 4390int os::stat(const char *path, struct stat *sbuf) { 4391 char pathbuf[MAX_PATH]; 4392 if (strlen(path) > MAX_PATH - 1) { 4393 errno = ENAMETOOLONG; 4394 return -1; 4395 } 4396 os::native_path(strcpy(pathbuf, path)); 4397 return ::stat(pathbuf, sbuf); 4398} 4399 4400bool os::check_heap(bool force) { 4401 return true; 4402} 4403 4404int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) { 4405 return ::vsnprintf(buf, count, format, args); 4406} 4407 4408// Is a (classpath) directory empty? 4409bool os::dir_is_empty(const char* path) { 4410 DIR *dir = NULL; 4411 struct dirent *ptr; 4412 4413 dir = opendir(path); 4414 if (dir == NULL) return true; 4415 4416 /* Scan the directory */ 4417 bool result = true; 4418 char buf[sizeof(struct dirent) + MAX_PATH]; 4419 while (result && (ptr = ::readdir(dir)) != NULL) { 4420 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 4421 result = false; 4422 } 4423 } 4424 closedir(dir); 4425 return result; 4426} 4427 4428// This code originates from JDK's sysOpen and open64_w 4429// from src/solaris/hpi/src/system_md.c 4430 4431#ifndef O_DELETE 4432#define O_DELETE 0x10000 4433#endif 4434 4435// Open a file. Unlink the file immediately after open returns 4436// if the specified oflag has the O_DELETE flag set. 4437// O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c 4438 4439int os::open(const char *path, int oflag, int mode) { 4440 4441 if (strlen(path) > MAX_PATH - 1) { 4442 errno = ENAMETOOLONG; 4443 return -1; 4444 } 4445 int fd; 4446 int o_delete = (oflag & O_DELETE); 4447 oflag = oflag & ~O_DELETE; 4448 4449 fd = ::open64(path, oflag, mode); 4450 if (fd == -1) return -1; 4451 4452 //If the open succeeded, the file might still be a directory 4453 { 4454 struct stat64 buf64; 4455 int ret = ::fstat64(fd, &buf64); 4456 int st_mode = buf64.st_mode; 4457 4458 if (ret != -1) { 4459 if ((st_mode & S_IFMT) == S_IFDIR) { 4460 errno = EISDIR; 4461 ::close(fd); 4462 return -1; 4463 } 4464 } else { 4465 ::close(fd); 4466 return -1; 4467 } 4468 } 4469 4470 /* 4471 * All file descriptors that are opened in the JVM and not 4472 * specifically destined for a subprocess should have the 4473 * close-on-exec flag set. If we don't set it, then careless 3rd 4474 * party native code might fork and exec without closing all 4475 * appropriate file descriptors (e.g. as we do in closeDescriptors in 4476 * UNIXProcess.c), and this in turn might: 4477 * 4478 * - cause end-of-file to fail to be detected on some file 4479 * descriptors, resulting in mysterious hangs, or 4480 * 4481 * - might cause an fopen in the subprocess to fail on a system 4482 * suffering from bug 1085341. 4483 * 4484 * (Yes, the default setting of the close-on-exec flag is a Unix 4485 * design flaw) 4486 * 4487 * See: 4488 * 1085341: 32-bit stdio routines should support file descriptors >255 4489 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed 4490 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 4491 */ 4492#ifdef FD_CLOEXEC 4493 { 4494 int flags = ::fcntl(fd, F_GETFD); 4495 if (flags != -1) 4496 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 4497 } 4498#endif 4499 4500 if (o_delete != 0) { 4501 ::unlink(path); 4502 } 4503 return fd; 4504} 4505 4506 4507// create binary file, rewriting existing file if required 4508int os::create_binary_file(const char* path, bool rewrite_existing) { 4509 int oflags = O_WRONLY | O_CREAT; 4510 if (!rewrite_existing) { 4511 oflags |= O_EXCL; 4512 } 4513 return ::open64(path, oflags, S_IREAD | S_IWRITE); 4514} 4515 4516// return current position of file pointer 4517jlong os::current_file_offset(int fd) { 4518 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 4519} 4520 4521// move file pointer to the specified offset 4522jlong os::seek_to_file_offset(int fd, jlong offset) { 4523 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 4524} 4525 4526// This code originates from JDK's sysAvailable 4527// from src/solaris/hpi/src/native_threads/src/sys_api_td.c 4528 4529int os::available(int fd, jlong *bytes) { 4530 jlong cur, end; 4531 int mode; 4532 struct stat64 buf64; 4533 4534 if (::fstat64(fd, &buf64) >= 0) { 4535 mode = buf64.st_mode; 4536 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 4537 /* 4538 * XXX: is the following call interruptible? If so, this might 4539 * need to go through the INTERRUPT_IO() wrapper as for other 4540 * blocking, interruptible calls in this file. 4541 */ 4542 int n; 4543 if (::ioctl(fd, FIONREAD, &n) >= 0) { 4544 *bytes = n; 4545 return 1; 4546 } 4547 } 4548 } 4549 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 4550 return 0; 4551 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 4552 return 0; 4553 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 4554 return 0; 4555 } 4556 *bytes = end - cur; 4557 return 1; 4558} 4559 4560int os::socket_available(int fd, jint *pbytes) { 4561 // Linux doc says EINTR not returned, unlike Solaris 4562 int ret = ::ioctl(fd, FIONREAD, pbytes); 4563 4564 //%% note ioctl can return 0 when successful, JVM_SocketAvailable 4565 // is expected to return 0 on failure and 1 on success to the jdk. 4566 return (ret < 0) ? 0 : 1; 4567} 4568 4569// Map a block of memory. 4570char* os::map_memory(int fd, const char* file_name, size_t file_offset, 4571 char *addr, size_t bytes, bool read_only, 4572 bool allow_exec) { 4573 int prot; 4574 int flags; 4575 4576 if (read_only) { 4577 prot = PROT_READ; 4578 flags = MAP_SHARED; 4579 } else { 4580 prot = PROT_READ | PROT_WRITE; 4581 flags = MAP_PRIVATE; 4582 } 4583 4584 if (allow_exec) { 4585 prot |= PROT_EXEC; 4586 } 4587 4588 if (addr != NULL) { 4589 flags |= MAP_FIXED; 4590 } 4591 4592 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 4593 fd, file_offset); 4594 if (mapped_address == MAP_FAILED) { 4595 return NULL; 4596 } 4597 return mapped_address; 4598} 4599 4600 4601// Remap a block of memory. 4602char* os::remap_memory(int fd, const char* file_name, size_t file_offset, 4603 char *addr, size_t bytes, bool read_only, 4604 bool allow_exec) { 4605 // same as map_memory() on this OS 4606 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 4607 allow_exec); 4608} 4609 4610 4611// Unmap a block of memory. 4612bool os::unmap_memory(char* addr, size_t bytes) { 4613 return munmap(addr, bytes) == 0; 4614} 4615 4616static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 4617 4618static clockid_t thread_cpu_clockid(Thread* thread) { 4619 pthread_t tid = thread->osthread()->pthread_id(); 4620 clockid_t clockid; 4621 4622 // Get thread clockid 4623 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 4624 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 4625 return clockid; 4626} 4627 4628// current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 4629// are used by JVM M&M and JVMTI to get user+sys or user CPU time 4630// of a thread. 4631// 4632// current_thread_cpu_time() and thread_cpu_time(Thread*) returns 4633// the fast estimate available on the platform. 4634 4635jlong os::current_thread_cpu_time() { 4636 if (os::Linux::supports_fast_thread_cpu_time()) { 4637 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4638 } else { 4639 // return user + sys since the cost is the same 4640 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 4641 } 4642} 4643 4644jlong os::thread_cpu_time(Thread* thread) { 4645 // consistent with what current_thread_cpu_time() returns 4646 if (os::Linux::supports_fast_thread_cpu_time()) { 4647 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4648 } else { 4649 return slow_thread_cpu_time(thread, true /* user + sys */); 4650 } 4651} 4652 4653jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 4654 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4655 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4656 } else { 4657 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 4658 } 4659} 4660 4661jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4662 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4663 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4664 } else { 4665 return slow_thread_cpu_time(thread, user_sys_cpu_time); 4666 } 4667} 4668 4669// 4670// -1 on error. 4671// 4672 4673static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4674 static bool proc_pid_cpu_avail = true; 4675 static bool proc_task_unchecked = true; 4676 static const char *proc_stat_path = "/proc/%d/stat"; 4677 pid_t tid = thread->osthread()->thread_id(); 4678 int i; 4679 char *s; 4680 char stat[2048]; 4681 int statlen; 4682 char proc_name[64]; 4683 int count; 4684 long sys_time, user_time; 4685 char string[64]; 4686 char cdummy; 4687 int idummy; 4688 long ldummy; 4689 FILE *fp; 4690 4691 // We first try accessing /proc/<pid>/cpu since this is faster to 4692 // process. If this file is not present (linux kernels 2.5 and above) 4693 // then we open /proc/<pid>/stat. 4694 if ( proc_pid_cpu_avail ) { 4695 sprintf(proc_name, "/proc/%d/cpu", tid); 4696 fp = fopen(proc_name, "r"); 4697 if ( fp != NULL ) { 4698 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time); 4699 fclose(fp); 4700 if ( count != 3 ) return -1; 4701 4702 if (user_sys_cpu_time) { 4703 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4704 } else { 4705 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4706 } 4707 } 4708 else proc_pid_cpu_avail = false; 4709 } 4710 4711 // The /proc/<tid>/stat aggregates per-process usage on 4712 // new Linux kernels 2.6+ where NPTL is supported. 4713 // The /proc/self/task/<tid>/stat still has the per-thread usage. 4714 // See bug 6328462. 4715 // There can be no directory /proc/self/task on kernels 2.4 with NPTL 4716 // and possibly in some other cases, so we check its availability. 4717 if (proc_task_unchecked && os::Linux::is_NPTL()) { 4718 // This is executed only once 4719 proc_task_unchecked = false; 4720 fp = fopen("/proc/self/task", "r"); 4721 if (fp != NULL) { 4722 proc_stat_path = "/proc/self/task/%d/stat"; 4723 fclose(fp); 4724 } 4725 } 4726 4727 sprintf(proc_name, proc_stat_path, tid); 4728 fp = fopen(proc_name, "r"); 4729 if ( fp == NULL ) return -1; 4730 statlen = fread(stat, 1, 2047, fp); 4731 stat[statlen] = '\0'; 4732 fclose(fp); 4733 4734 // Skip pid and the command string. Note that we could be dealing with 4735 // weird command names, e.g. user could decide to rename java launcher 4736 // to "java 1.4.2 :)", then the stat file would look like 4737 // 1234 (java 1.4.2 :)) R ... ... 4738 // We don't really need to know the command string, just find the last 4739 // occurrence of ")" and then start parsing from there. See bug 4726580. 4740 s = strrchr(stat, ')'); 4741 i = 0; 4742 if (s == NULL ) return -1; 4743 4744 // Skip blank chars 4745 do s++; while (isspace(*s)); 4746 4747 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 4748 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 4749 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 4750 &user_time, &sys_time); 4751 if ( count != 13 ) return -1; 4752 if (user_sys_cpu_time) { 4753 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4754 } else { 4755 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4756 } 4757} 4758 4759void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4760 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4761 info_ptr->may_skip_backward = false; // elapsed time not wall time 4762 info_ptr->may_skip_forward = false; // elapsed time not wall time 4763 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4764} 4765 4766void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4767 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4768 info_ptr->may_skip_backward = false; // elapsed time not wall time 4769 info_ptr->may_skip_forward = false; // elapsed time not wall time 4770 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4771} 4772 4773bool os::is_thread_cpu_time_supported() { 4774 return true; 4775} 4776 4777// System loadavg support. Returns -1 if load average cannot be obtained. 4778// Linux doesn't yet have a (official) notion of processor sets, 4779// so just return the system wide load average. 4780int os::loadavg(double loadavg[], int nelem) { 4781 return ::getloadavg(loadavg, nelem); 4782} 4783 4784void os::pause() { 4785 char filename[MAX_PATH]; 4786 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 4787 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 4788 } else { 4789 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 4790 } 4791 4792 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 4793 if (fd != -1) { 4794 struct stat buf; 4795 ::close(fd); 4796 while (::stat(filename, &buf) == 0) { 4797 (void)::poll(NULL, 0, 100); 4798 } 4799 } else { 4800 jio_fprintf(stderr, 4801 "Could not open pause file '%s', continuing immediately.\n", filename); 4802 } 4803} 4804 4805 4806// Refer to the comments in os_solaris.cpp park-unpark. 4807// 4808// Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 4809// hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 4810// For specifics regarding the bug see GLIBC BUGID 261237 : 4811// http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 4812// Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 4813// will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 4814// is used. (The simple C test-case provided in the GLIBC bug report manifests the 4815// hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 4816// and monitorenter when we're using 1-0 locking. All those operations may result in 4817// calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 4818// of libpthread avoids the problem, but isn't practical. 4819// 4820// Possible remedies: 4821// 4822// 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 4823// This is palliative and probabilistic, however. If the thread is preempted 4824// between the call to compute_abstime() and pthread_cond_timedwait(), more 4825// than the minimum period may have passed, and the abstime may be stale (in the 4826// past) resultin in a hang. Using this technique reduces the odds of a hang 4827// but the JVM is still vulnerable, particularly on heavily loaded systems. 4828// 4829// 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 4830// of the usual flag-condvar-mutex idiom. The write side of the pipe is set 4831// NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 4832// reduces to poll()+read(). This works well, but consumes 2 FDs per extant 4833// thread. 4834// 4835// 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 4836// that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 4837// a timeout request to the chron thread and then blocking via pthread_cond_wait(). 4838// This also works well. In fact it avoids kernel-level scalability impediments 4839// on certain platforms that don't handle lots of active pthread_cond_timedwait() 4840// timers in a graceful fashion. 4841// 4842// 4. When the abstime value is in the past it appears that control returns 4843// correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 4844// Subsequent timedwait/wait calls may hang indefinitely. Given that, we 4845// can avoid the problem by reinitializing the condvar -- by cond_destroy() 4846// followed by cond_init() -- after all calls to pthread_cond_timedwait(). 4847// It may be possible to avoid reinitialization by checking the return 4848// value from pthread_cond_timedwait(). In addition to reinitializing the 4849// condvar we must establish the invariant that cond_signal() is only called 4850// within critical sections protected by the adjunct mutex. This prevents 4851// cond_signal() from "seeing" a condvar that's in the midst of being 4852// reinitialized or that is corrupt. Sadly, this invariant obviates the 4853// desirable signal-after-unlock optimization that avoids futile context switching. 4854// 4855// I'm also concerned that some versions of NTPL might allocate an auxilliary 4856// structure when a condvar is used or initialized. cond_destroy() would 4857// release the helper structure. Our reinitialize-after-timedwait fix 4858// put excessive stress on malloc/free and locks protecting the c-heap. 4859// 4860// We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 4861// It may be possible to refine (4) by checking the kernel and NTPL verisons 4862// and only enabling the work-around for vulnerable environments. 4863 4864// utility to compute the abstime argument to timedwait: 4865// millis is the relative timeout time 4866// abstime will be the absolute timeout time 4867// TODO: replace compute_abstime() with unpackTime() 4868 4869static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 4870 if (millis < 0) millis = 0; 4871 struct timeval now; 4872 int status = gettimeofday(&now, NULL); 4873 assert(status == 0, "gettimeofday"); 4874 jlong seconds = millis / 1000; 4875 millis %= 1000; 4876 if (seconds > 50000000) { // see man cond_timedwait(3T) 4877 seconds = 50000000; 4878 } 4879 abstime->tv_sec = now.tv_sec + seconds; 4880 long usec = now.tv_usec + millis * 1000; 4881 if (usec >= 1000000) { 4882 abstime->tv_sec += 1; 4883 usec -= 1000000; 4884 } 4885 abstime->tv_nsec = usec * 1000; 4886 return abstime; 4887} 4888 4889 4890// Test-and-clear _Event, always leaves _Event set to 0, returns immediately. 4891// Conceptually TryPark() should be equivalent to park(0). 4892 4893int os::PlatformEvent::TryPark() { 4894 for (;;) { 4895 const int v = _Event ; 4896 guarantee ((v == 0) || (v == 1), "invariant") ; 4897 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ; 4898 } 4899} 4900 4901void os::PlatformEvent::park() { // AKA "down()" 4902 // Invariant: Only the thread associated with the Event/PlatformEvent 4903 // may call park(). 4904 // TODO: assert that _Assoc != NULL or _Assoc == Self 4905 int v ; 4906 for (;;) { 4907 v = _Event ; 4908 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 4909 } 4910 guarantee (v >= 0, "invariant") ; 4911 if (v == 0) { 4912 // Do this the hard way by blocking ... 4913 int status = pthread_mutex_lock(_mutex); 4914 assert_status(status == 0, status, "mutex_lock"); 4915 guarantee (_nParked == 0, "invariant") ; 4916 ++ _nParked ; 4917 while (_Event < 0) { 4918 status = pthread_cond_wait(_cond, _mutex); 4919 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 4920 // Treat this the same as if the wait was interrupted 4921 if (status == ETIME) { status = EINTR; } 4922 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 4923 } 4924 -- _nParked ; 4925 4926 // In theory we could move the ST of 0 into _Event past the unlock(), 4927 // but then we'd need a MEMBAR after the ST. 4928 _Event = 0 ; 4929 status = pthread_mutex_unlock(_mutex); 4930 assert_status(status == 0, status, "mutex_unlock"); 4931 } 4932 guarantee (_Event >= 0, "invariant") ; 4933} 4934 4935int os::PlatformEvent::park(jlong millis) { 4936 guarantee (_nParked == 0, "invariant") ; 4937 4938 int v ; 4939 for (;;) { 4940 v = _Event ; 4941 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 4942 } 4943 guarantee (v >= 0, "invariant") ; 4944 if (v != 0) return OS_OK ; 4945 4946 // We do this the hard way, by blocking the thread. 4947 // Consider enforcing a minimum timeout value. 4948 struct timespec abst; 4949 compute_abstime(&abst, millis); 4950 4951 int ret = OS_TIMEOUT; 4952 int status = pthread_mutex_lock(_mutex); 4953 assert_status(status == 0, status, "mutex_lock"); 4954 guarantee (_nParked == 0, "invariant") ; 4955 ++_nParked ; 4956 4957 // Object.wait(timo) will return because of 4958 // (a) notification 4959 // (b) timeout 4960 // (c) thread.interrupt 4961 // 4962 // Thread.interrupt and object.notify{All} both call Event::set. 4963 // That is, we treat thread.interrupt as a special case of notification. 4964 // The underlying Solaris implementation, cond_timedwait, admits 4965 // spurious/premature wakeups, but the JLS/JVM spec prevents the 4966 // JVM from making those visible to Java code. As such, we must 4967 // filter out spurious wakeups. We assume all ETIME returns are valid. 4968 // 4969 // TODO: properly differentiate simultaneous notify+interrupt. 4970 // In that case, we should propagate the notify to another waiter. 4971 4972 while (_Event < 0) { 4973 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst); 4974 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 4975 pthread_cond_destroy (_cond); 4976 pthread_cond_init (_cond, NULL) ; 4977 } 4978 assert_status(status == 0 || status == EINTR || 4979 status == ETIME || status == ETIMEDOUT, 4980 status, "cond_timedwait"); 4981 if (!FilterSpuriousWakeups) break ; // previous semantics 4982 if (status == ETIME || status == ETIMEDOUT) break ; 4983 // We consume and ignore EINTR and spurious wakeups. 4984 } 4985 --_nParked ; 4986 if (_Event >= 0) { 4987 ret = OS_OK; 4988 } 4989 _Event = 0 ; 4990 status = pthread_mutex_unlock(_mutex); 4991 assert_status(status == 0, status, "mutex_unlock"); 4992 assert (_nParked == 0, "invariant") ; 4993 return ret; 4994} 4995 4996void os::PlatformEvent::unpark() { 4997 int v, AnyWaiters ; 4998 for (;;) { 4999 v = _Event ; 5000 if (v > 0) { 5001 // The LD of _Event could have reordered or be satisfied 5002 // by a read-aside from this processor's write buffer. 5003 // To avoid problems execute a barrier and then 5004 // ratify the value. 5005 OrderAccess::fence() ; 5006 if (_Event == v) return ; 5007 continue ; 5008 } 5009 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ; 5010 } 5011 if (v < 0) { 5012 // Wait for the thread associated with the event to vacate 5013 int status = pthread_mutex_lock(_mutex); 5014 assert_status(status == 0, status, "mutex_lock"); 5015 AnyWaiters = _nParked ; 5016 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ; 5017 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 5018 AnyWaiters = 0 ; 5019 pthread_cond_signal (_cond); 5020 } 5021 status = pthread_mutex_unlock(_mutex); 5022 assert_status(status == 0, status, "mutex_unlock"); 5023 if (AnyWaiters != 0) { 5024 status = pthread_cond_signal(_cond); 5025 assert_status(status == 0, status, "cond_signal"); 5026 } 5027 } 5028 5029 // Note that we signal() _after dropping the lock for "immortal" Events. 5030 // This is safe and avoids a common class of futile wakeups. In rare 5031 // circumstances this can cause a thread to return prematurely from 5032 // cond_{timed}wait() but the spurious wakeup is benign and the victim will 5033 // simply re-test the condition and re-park itself. 5034} 5035 5036 5037// JSR166 5038// ------------------------------------------------------- 5039 5040/* 5041 * The solaris and linux implementations of park/unpark are fairly 5042 * conservative for now, but can be improved. They currently use a 5043 * mutex/condvar pair, plus a a count. 5044 * Park decrements count if > 0, else does a condvar wait. Unpark 5045 * sets count to 1 and signals condvar. Only one thread ever waits 5046 * on the condvar. Contention seen when trying to park implies that someone 5047 * is unparking you, so don't wait. And spurious returns are fine, so there 5048 * is no need to track notifications. 5049 */ 5050 5051 5052#define NANOSECS_PER_SEC 1000000000 5053#define NANOSECS_PER_MILLISEC 1000000 5054#define MAX_SECS 100000000 5055/* 5056 * This code is common to linux and solaris and will be moved to a 5057 * common place in dolphin. 5058 * 5059 * The passed in time value is either a relative time in nanoseconds 5060 * or an absolute time in milliseconds. Either way it has to be unpacked 5061 * into suitable seconds and nanoseconds components and stored in the 5062 * given timespec structure. 5063 * Given time is a 64-bit value and the time_t used in the timespec is only 5064 * a signed-32-bit value (except on 64-bit Linux) we have to watch for 5065 * overflow if times way in the future are given. Further on Solaris versions 5066 * prior to 10 there is a restriction (see cond_timedwait) that the specified 5067 * number of seconds, in abstime, is less than current_time + 100,000,000. 5068 * As it will be 28 years before "now + 100000000" will overflow we can 5069 * ignore overflow and just impose a hard-limit on seconds using the value 5070 * of "now + 100,000,000". This places a limit on the timeout of about 3.17 5071 * years from "now". 5072 */ 5073 5074static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5075 assert (time > 0, "convertTime"); 5076 5077 struct timeval now; 5078 int status = gettimeofday(&now, NULL); 5079 assert(status == 0, "gettimeofday"); 5080 5081 time_t max_secs = now.tv_sec + MAX_SECS; 5082 5083 if (isAbsolute) { 5084 jlong secs = time / 1000; 5085 if (secs > max_secs) { 5086 absTime->tv_sec = max_secs; 5087 } 5088 else { 5089 absTime->tv_sec = secs; 5090 } 5091 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5092 } 5093 else { 5094 jlong secs = time / NANOSECS_PER_SEC; 5095 if (secs >= MAX_SECS) { 5096 absTime->tv_sec = max_secs; 5097 absTime->tv_nsec = 0; 5098 } 5099 else { 5100 absTime->tv_sec = now.tv_sec + secs; 5101 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5102 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5103 absTime->tv_nsec -= NANOSECS_PER_SEC; 5104 ++absTime->tv_sec; // note: this must be <= max_secs 5105 } 5106 } 5107 } 5108 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5109 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5110 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5111 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5112} 5113 5114void Parker::park(bool isAbsolute, jlong time) { 5115 // Optional fast-path check: 5116 // Return immediately if a permit is available. 5117 if (_counter > 0) { 5118 _counter = 0 ; 5119 OrderAccess::fence(); 5120 return ; 5121 } 5122 5123 Thread* thread = Thread::current(); 5124 assert(thread->is_Java_thread(), "Must be JavaThread"); 5125 JavaThread *jt = (JavaThread *)thread; 5126 5127 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5128 // Check interrupt before trying to wait 5129 if (Thread::is_interrupted(thread, false)) { 5130 return; 5131 } 5132 5133 // Next, demultiplex/decode time arguments 5134 timespec absTime; 5135 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all 5136 return; 5137 } 5138 if (time > 0) { 5139 unpackTime(&absTime, isAbsolute, time); 5140 } 5141 5142 5143 // Enter safepoint region 5144 // Beware of deadlocks such as 6317397. 5145 // The per-thread Parker:: mutex is a classic leaf-lock. 5146 // In particular a thread must never block on the Threads_lock while 5147 // holding the Parker:: mutex. If safepoints are pending both the 5148 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5149 ThreadBlockInVM tbivm(jt); 5150 5151 // Don't wait if cannot get lock since interference arises from 5152 // unblocking. Also. check interrupt before trying wait 5153 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5154 return; 5155 } 5156 5157 int status ; 5158 if (_counter > 0) { // no wait needed 5159 _counter = 0; 5160 status = pthread_mutex_unlock(_mutex); 5161 assert (status == 0, "invariant") ; 5162 OrderAccess::fence(); 5163 return; 5164 } 5165 5166#ifdef ASSERT 5167 // Don't catch signals while blocked; let the running threads have the signals. 5168 // (This allows a debugger to break into the running thread.) 5169 sigset_t oldsigs; 5170 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5171 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5172#endif 5173 5174 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5175 jt->set_suspend_equivalent(); 5176 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5177 5178 if (time == 0) { 5179 status = pthread_cond_wait (_cond, _mutex) ; 5180 } else { 5181 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ; 5182 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5183 pthread_cond_destroy (_cond) ; 5184 pthread_cond_init (_cond, NULL); 5185 } 5186 } 5187 assert_status(status == 0 || status == EINTR || 5188 status == ETIME || status == ETIMEDOUT, 5189 status, "cond_timedwait"); 5190 5191#ifdef ASSERT 5192 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5193#endif 5194 5195 _counter = 0 ; 5196 status = pthread_mutex_unlock(_mutex) ; 5197 assert_status(status == 0, status, "invariant") ; 5198 // If externally suspended while waiting, re-suspend 5199 if (jt->handle_special_suspend_equivalent_condition()) { 5200 jt->java_suspend_self(); 5201 } 5202 5203 OrderAccess::fence(); 5204} 5205 5206void Parker::unpark() { 5207 int s, status ; 5208 status = pthread_mutex_lock(_mutex); 5209 assert (status == 0, "invariant") ; 5210 s = _counter; 5211 _counter = 1; 5212 if (s < 1) { 5213 if (WorkAroundNPTLTimedWaitHang) { 5214 status = pthread_cond_signal (_cond) ; 5215 assert (status == 0, "invariant") ; 5216 status = pthread_mutex_unlock(_mutex); 5217 assert (status == 0, "invariant") ; 5218 } else { 5219 status = pthread_mutex_unlock(_mutex); 5220 assert (status == 0, "invariant") ; 5221 status = pthread_cond_signal (_cond) ; 5222 assert (status == 0, "invariant") ; 5223 } 5224 } else { 5225 pthread_mutex_unlock(_mutex); 5226 assert (status == 0, "invariant") ; 5227 } 5228} 5229 5230 5231extern char** environ; 5232 5233#ifndef __NR_fork 5234#define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) 5235#endif 5236 5237#ifndef __NR_execve 5238#define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) 5239#endif 5240 5241// Run the specified command in a separate process. Return its exit value, 5242// or -1 on failure (e.g. can't fork a new process). 5243// Unlike system(), this function can be called from signal handler. It 5244// doesn't block SIGINT et al. 5245int os::fork_and_exec(char* cmd) { 5246 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5247 5248 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run 5249 // pthread_atfork handlers and reset pthread library. All we need is a 5250 // separate process to execve. Make a direct syscall to fork process. 5251 // On IA64 there's no fork syscall, we have to use fork() and hope for 5252 // the best... 5253 pid_t pid = NOT_IA64(syscall(__NR_fork);) 5254 IA64_ONLY(fork();) 5255 5256 if (pid < 0) { 5257 // fork failed 5258 return -1; 5259 5260 } else if (pid == 0) { 5261 // child process 5262 5263 // execve() in LinuxThreads will call pthread_kill_other_threads_np() 5264 // first to kill every thread on the thread list. Because this list is 5265 // not reset by fork() (see notes above), execve() will instead kill 5266 // every thread in the parent process. We know this is the only thread 5267 // in the new process, so make a system call directly. 5268 // IA64 should use normal execve() from glibc to match the glibc fork() 5269 // above. 5270 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);) 5271 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);) 5272 5273 // execve failed 5274 _exit(-1); 5275 5276 } else { 5277 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5278 // care about the actual exit code, for now. 5279 5280 int status; 5281 5282 // Wait for the child process to exit. This returns immediately if 5283 // the child has already exited. */ 5284 while (waitpid(pid, &status, 0) < 0) { 5285 switch (errno) { 5286 case ECHILD: return 0; 5287 case EINTR: break; 5288 default: return -1; 5289 } 5290 } 5291 5292 if (WIFEXITED(status)) { 5293 // The child exited normally; get its exit code. 5294 return WEXITSTATUS(status); 5295 } else if (WIFSIGNALED(status)) { 5296 // The child exited because of a signal 5297 // The best value to return is 0x80 + signal number, 5298 // because that is what all Unix shells do, and because 5299 // it allows callers to distinguish between process exit and 5300 // process death by signal. 5301 return 0x80 + WTERMSIG(status); 5302 } else { 5303 // Unknown exit code; pass it through 5304 return status; 5305 } 5306 } 5307} 5308 5309// is_headless_jre() 5310// 5311// Test for the existence of libmawt in motif21 or xawt directories 5312// in order to report if we are running in a headless jre 5313// 5314bool os::is_headless_jre() { 5315 struct stat statbuf; 5316 char buf[MAXPATHLEN]; 5317 char libmawtpath[MAXPATHLEN]; 5318 const char *xawtstr = "/xawt/libmawt.so"; 5319 const char *motifstr = "/motif21/libmawt.so"; 5320 char *p; 5321 5322 // Get path to libjvm.so 5323 os::jvm_path(buf, sizeof(buf)); 5324 5325 // Get rid of libjvm.so 5326 p = strrchr(buf, '/'); 5327 if (p == NULL) return false; 5328 else *p = '\0'; 5329 5330 // Get rid of client or server 5331 p = strrchr(buf, '/'); 5332 if (p == NULL) return false; 5333 else *p = '\0'; 5334 5335 // check xawt/libmawt.so 5336 strcpy(libmawtpath, buf); 5337 strcat(libmawtpath, xawtstr); 5338 if (::stat(libmawtpath, &statbuf) == 0) return false; 5339 5340 // check motif21/libmawt.so 5341 strcpy(libmawtpath, buf); 5342 strcat(libmawtpath, motifstr); 5343 if (::stat(libmawtpath, &statbuf) == 0) return false; 5344 5345 return true; 5346} 5347 5348