os_linux.cpp revision 4769:e72f7eecc96d
1/* 2 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25// no precompiled headers 26#include "classfile/classLoader.hpp" 27#include "classfile/systemDictionary.hpp" 28#include "classfile/vmSymbols.hpp" 29#include "code/icBuffer.hpp" 30#include "code/vtableStubs.hpp" 31#include "compiler/compileBroker.hpp" 32#include "compiler/disassembler.hpp" 33#include "interpreter/interpreter.hpp" 34#include "jvm_linux.h" 35#include "memory/allocation.inline.hpp" 36#include "memory/filemap.hpp" 37#include "mutex_linux.inline.hpp" 38#include "oops/oop.inline.hpp" 39#include "os_share_linux.hpp" 40#include "prims/jniFastGetField.hpp" 41#include "prims/jvm.h" 42#include "prims/jvm_misc.hpp" 43#include "runtime/arguments.hpp" 44#include "runtime/extendedPC.hpp" 45#include "runtime/globals.hpp" 46#include "runtime/interfaceSupport.hpp" 47#include "runtime/init.hpp" 48#include "runtime/java.hpp" 49#include "runtime/javaCalls.hpp" 50#include "runtime/mutexLocker.hpp" 51#include "runtime/objectMonitor.hpp" 52#include "runtime/osThread.hpp" 53#include "runtime/perfMemory.hpp" 54#include "runtime/sharedRuntime.hpp" 55#include "runtime/statSampler.hpp" 56#include "runtime/stubRoutines.hpp" 57#include "runtime/thread.inline.hpp" 58#include "runtime/threadCritical.hpp" 59#include "runtime/timer.hpp" 60#include "services/attachListener.hpp" 61#include "services/memTracker.hpp" 62#include "services/runtimeService.hpp" 63#include "utilities/decoder.hpp" 64#include "utilities/defaultStream.hpp" 65#include "utilities/events.hpp" 66#include "utilities/elfFile.hpp" 67#include "utilities/growableArray.hpp" 68#include "utilities/vmError.hpp" 69 70// put OS-includes here 71# include <sys/types.h> 72# include <sys/mman.h> 73# include <sys/stat.h> 74# include <sys/select.h> 75# include <pthread.h> 76# include <signal.h> 77# include <errno.h> 78# include <dlfcn.h> 79# include <stdio.h> 80# include <unistd.h> 81# include <sys/resource.h> 82# include <pthread.h> 83# include <sys/stat.h> 84# include <sys/time.h> 85# include <sys/times.h> 86# include <sys/utsname.h> 87# include <sys/socket.h> 88# include <sys/wait.h> 89# include <pwd.h> 90# include <poll.h> 91# include <semaphore.h> 92# include <fcntl.h> 93# include <string.h> 94# include <syscall.h> 95# include <sys/sysinfo.h> 96# include <gnu/libc-version.h> 97# include <sys/ipc.h> 98# include <sys/shm.h> 99# include <link.h> 100# include <stdint.h> 101# include <inttypes.h> 102# include <sys/ioctl.h> 103 104// if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 105// getrusage() is prepared to handle the associated failure. 106#ifndef RUSAGE_THREAD 107#define RUSAGE_THREAD (1) /* only the calling thread */ 108#endif 109 110#define MAX_PATH (2 * K) 111 112// for timer info max values which include all bits 113#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 114 115#define LARGEPAGES_BIT (1 << 6) 116//////////////////////////////////////////////////////////////////////////////// 117// global variables 118julong os::Linux::_physical_memory = 0; 119 120address os::Linux::_initial_thread_stack_bottom = NULL; 121uintptr_t os::Linux::_initial_thread_stack_size = 0; 122 123int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 124int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 125Mutex* os::Linux::_createThread_lock = NULL; 126pthread_t os::Linux::_main_thread; 127int os::Linux::_page_size = -1; 128const int os::Linux::_vm_default_page_size = (8 * K); 129bool os::Linux::_is_floating_stack = false; 130bool os::Linux::_is_NPTL = false; 131bool os::Linux::_supports_fast_thread_cpu_time = false; 132const char * os::Linux::_glibc_version = NULL; 133const char * os::Linux::_libpthread_version = NULL; 134 135static jlong initial_time_count=0; 136 137static int clock_tics_per_sec = 100; 138 139// For diagnostics to print a message once. see run_periodic_checks 140static sigset_t check_signal_done; 141static bool check_signals = true;; 142 143static pid_t _initial_pid = 0; 144 145/* Signal number used to suspend/resume a thread */ 146 147/* do not use any signal number less than SIGSEGV, see 4355769 */ 148static int SR_signum = SIGUSR2; 149sigset_t SR_sigset; 150 151/* Used to protect dlsym() calls */ 152static pthread_mutex_t dl_mutex; 153 154#ifdef JAVASE_EMBEDDED 155class MemNotifyThread: public Thread { 156 friend class VMStructs; 157 public: 158 virtual void run(); 159 160 private: 161 static MemNotifyThread* _memnotify_thread; 162 int _fd; 163 164 public: 165 166 // Constructor 167 MemNotifyThread(int fd); 168 169 // Tester 170 bool is_memnotify_thread() const { return true; } 171 172 // Printing 173 char* name() const { return (char*)"Linux MemNotify Thread"; } 174 175 // Returns the single instance of the MemNotifyThread 176 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; } 177 178 // Create and start the single instance of MemNotifyThread 179 static void start(); 180}; 181#endif // JAVASE_EMBEDDED 182 183// utility functions 184 185static int SR_initialize(); 186 187julong os::available_memory() { 188 return Linux::available_memory(); 189} 190 191julong os::Linux::available_memory() { 192 // values in struct sysinfo are "unsigned long" 193 struct sysinfo si; 194 sysinfo(&si); 195 196 return (julong)si.freeram * si.mem_unit; 197} 198 199julong os::physical_memory() { 200 return Linux::physical_memory(); 201} 202 203//////////////////////////////////////////////////////////////////////////////// 204// environment support 205 206bool os::getenv(const char* name, char* buf, int len) { 207 const char* val = ::getenv(name); 208 if (val != NULL && strlen(val) < (size_t)len) { 209 strcpy(buf, val); 210 return true; 211 } 212 if (len > 0) buf[0] = 0; // return a null string 213 return false; 214} 215 216 217// Return true if user is running as root. 218 219bool os::have_special_privileges() { 220 static bool init = false; 221 static bool privileges = false; 222 if (!init) { 223 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 224 init = true; 225 } 226 return privileges; 227} 228 229 230#ifndef SYS_gettid 231// i386: 224, ia64: 1105, amd64: 186, sparc 143 232#ifdef __ia64__ 233#define SYS_gettid 1105 234#elif __i386__ 235#define SYS_gettid 224 236#elif __amd64__ 237#define SYS_gettid 186 238#elif __sparc__ 239#define SYS_gettid 143 240#else 241#error define gettid for the arch 242#endif 243#endif 244 245// Cpu architecture string 246#if defined(ZERO) 247static char cpu_arch[] = ZERO_LIBARCH; 248#elif defined(IA64) 249static char cpu_arch[] = "ia64"; 250#elif defined(IA32) 251static char cpu_arch[] = "i386"; 252#elif defined(AMD64) 253static char cpu_arch[] = "amd64"; 254#elif defined(ARM) 255static char cpu_arch[] = "arm"; 256#elif defined(PPC) 257static char cpu_arch[] = "ppc"; 258#elif defined(SPARC) 259# ifdef _LP64 260static char cpu_arch[] = "sparcv9"; 261# else 262static char cpu_arch[] = "sparc"; 263# endif 264#else 265#error Add appropriate cpu_arch setting 266#endif 267 268 269// pid_t gettid() 270// 271// Returns the kernel thread id of the currently running thread. Kernel 272// thread id is used to access /proc. 273// 274// (Note that getpid() on LinuxThreads returns kernel thread id too; but 275// on NPTL, it returns the same pid for all threads, as required by POSIX.) 276// 277pid_t os::Linux::gettid() { 278 int rslt = syscall(SYS_gettid); 279 if (rslt == -1) { 280 // old kernel, no NPTL support 281 return getpid(); 282 } else { 283 return (pid_t)rslt; 284 } 285} 286 287// Most versions of linux have a bug where the number of processors are 288// determined by looking at the /proc file system. In a chroot environment, 289// the system call returns 1. This causes the VM to act as if it is 290// a single processor and elide locking (see is_MP() call). 291static bool unsafe_chroot_detected = false; 292static const char *unstable_chroot_error = "/proc file system not found.\n" 293 "Java may be unstable running multithreaded in a chroot " 294 "environment on Linux when /proc filesystem is not mounted."; 295 296void os::Linux::initialize_system_info() { 297 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 298 if (processor_count() == 1) { 299 pid_t pid = os::Linux::gettid(); 300 char fname[32]; 301 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 302 FILE *fp = fopen(fname, "r"); 303 if (fp == NULL) { 304 unsafe_chroot_detected = true; 305 } else { 306 fclose(fp); 307 } 308 } 309 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 310 assert(processor_count() > 0, "linux error"); 311} 312 313void os::init_system_properties_values() { 314// char arch[12]; 315// sysinfo(SI_ARCHITECTURE, arch, sizeof(arch)); 316 317 // The next steps are taken in the product version: 318 // 319 // Obtain the JAVA_HOME value from the location of libjvm.so. 320 // This library should be located at: 321 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so. 322 // 323 // If "/jre/lib/" appears at the right place in the path, then we 324 // assume libjvm.so is installed in a JDK and we use this path. 325 // 326 // Otherwise exit with message: "Could not create the Java virtual machine." 327 // 328 // The following extra steps are taken in the debugging version: 329 // 330 // If "/jre/lib/" does NOT appear at the right place in the path 331 // instead of exit check for $JAVA_HOME environment variable. 332 // 333 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 334 // then we append a fake suffix "hotspot/libjvm.so" to this path so 335 // it looks like libjvm.so is installed there 336 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 337 // 338 // Otherwise exit. 339 // 340 // Important note: if the location of libjvm.so changes this 341 // code needs to be changed accordingly. 342 343 // The next few definitions allow the code to be verbatim: 344#define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n), mtInternal) 345#define getenv(n) ::getenv(n) 346 347/* 348 * See ld(1): 349 * The linker uses the following search paths to locate required 350 * shared libraries: 351 * 1: ... 352 * ... 353 * 7: The default directories, normally /lib and /usr/lib. 354 */ 355#if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 356#define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 357#else 358#define DEFAULT_LIBPATH "/lib:/usr/lib" 359#endif 360 361#define EXTENSIONS_DIR "/lib/ext" 362#define ENDORSED_DIR "/lib/endorsed" 363#define REG_DIR "/usr/java/packages" 364 365 { 366 /* sysclasspath, java_home, dll_dir */ 367 { 368 char *home_path; 369 char *dll_path; 370 char *pslash; 371 char buf[MAXPATHLEN]; 372 os::jvm_path(buf, sizeof(buf)); 373 374 // Found the full path to libjvm.so. 375 // Now cut the path to <java_home>/jre if we can. 376 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */ 377 pslash = strrchr(buf, '/'); 378 if (pslash != NULL) 379 *pslash = '\0'; /* get rid of /{client|server|hotspot} */ 380 dll_path = malloc(strlen(buf) + 1); 381 if (dll_path == NULL) 382 return; 383 strcpy(dll_path, buf); 384 Arguments::set_dll_dir(dll_path); 385 386 if (pslash != NULL) { 387 pslash = strrchr(buf, '/'); 388 if (pslash != NULL) { 389 *pslash = '\0'; /* get rid of /<arch> */ 390 pslash = strrchr(buf, '/'); 391 if (pslash != NULL) 392 *pslash = '\0'; /* get rid of /lib */ 393 } 394 } 395 396 home_path = malloc(strlen(buf) + 1); 397 if (home_path == NULL) 398 return; 399 strcpy(home_path, buf); 400 Arguments::set_java_home(home_path); 401 402 if (!set_boot_path('/', ':')) 403 return; 404 } 405 406 /* 407 * Where to look for native libraries 408 * 409 * Note: Due to a legacy implementation, most of the library path 410 * is set in the launcher. This was to accomodate linking restrictions 411 * on legacy Linux implementations (which are no longer supported). 412 * Eventually, all the library path setting will be done here. 413 * 414 * However, to prevent the proliferation of improperly built native 415 * libraries, the new path component /usr/java/packages is added here. 416 * Eventually, all the library path setting will be done here. 417 */ 418 { 419 char *ld_library_path; 420 421 /* 422 * Construct the invariant part of ld_library_path. Note that the 423 * space for the colon and the trailing null are provided by the 424 * nulls included by the sizeof operator (so actually we allocate 425 * a byte more than necessary). 426 */ 427 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") + 428 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH)); 429 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch); 430 431 /* 432 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It 433 * should always exist (until the legacy problem cited above is 434 * addressed). 435 */ 436 char *v = getenv("LD_LIBRARY_PATH"); 437 if (v != NULL) { 438 char *t = ld_library_path; 439 /* That's +1 for the colon and +1 for the trailing '\0' */ 440 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1); 441 sprintf(ld_library_path, "%s:%s", v, t); 442 } 443 Arguments::set_library_path(ld_library_path); 444 } 445 446 /* 447 * Extensions directories. 448 * 449 * Note that the space for the colon and the trailing null are provided 450 * by the nulls included by the sizeof operator (so actually one byte more 451 * than necessary is allocated). 452 */ 453 { 454 char *buf = malloc(strlen(Arguments::get_java_home()) + 455 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR)); 456 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR, 457 Arguments::get_java_home()); 458 Arguments::set_ext_dirs(buf); 459 } 460 461 /* Endorsed standards default directory. */ 462 { 463 char * buf; 464 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR)); 465 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home()); 466 Arguments::set_endorsed_dirs(buf); 467 } 468 } 469 470#undef malloc 471#undef getenv 472#undef EXTENSIONS_DIR 473#undef ENDORSED_DIR 474 475 // Done 476 return; 477} 478 479//////////////////////////////////////////////////////////////////////////////// 480// breakpoint support 481 482void os::breakpoint() { 483 BREAKPOINT; 484} 485 486extern "C" void breakpoint() { 487 // use debugger to set breakpoint here 488} 489 490//////////////////////////////////////////////////////////////////////////////// 491// signal support 492 493debug_only(static bool signal_sets_initialized = false); 494static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 495 496bool os::Linux::is_sig_ignored(int sig) { 497 struct sigaction oact; 498 sigaction(sig, (struct sigaction*)NULL, &oact); 499 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 500 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 501 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) 502 return true; 503 else 504 return false; 505} 506 507void os::Linux::signal_sets_init() { 508 // Should also have an assertion stating we are still single-threaded. 509 assert(!signal_sets_initialized, "Already initialized"); 510 // Fill in signals that are necessarily unblocked for all threads in 511 // the VM. Currently, we unblock the following signals: 512 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 513 // by -Xrs (=ReduceSignalUsage)); 514 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 515 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 516 // the dispositions or masks wrt these signals. 517 // Programs embedding the VM that want to use the above signals for their 518 // own purposes must, at this time, use the "-Xrs" option to prevent 519 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 520 // (See bug 4345157, and other related bugs). 521 // In reality, though, unblocking these signals is really a nop, since 522 // these signals are not blocked by default. 523 sigemptyset(&unblocked_sigs); 524 sigemptyset(&allowdebug_blocked_sigs); 525 sigaddset(&unblocked_sigs, SIGILL); 526 sigaddset(&unblocked_sigs, SIGSEGV); 527 sigaddset(&unblocked_sigs, SIGBUS); 528 sigaddset(&unblocked_sigs, SIGFPE); 529 sigaddset(&unblocked_sigs, SR_signum); 530 531 if (!ReduceSignalUsage) { 532 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 533 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 534 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 535 } 536 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 537 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 538 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 539 } 540 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 541 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 542 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 543 } 544 } 545 // Fill in signals that are blocked by all but the VM thread. 546 sigemptyset(&vm_sigs); 547 if (!ReduceSignalUsage) 548 sigaddset(&vm_sigs, BREAK_SIGNAL); 549 debug_only(signal_sets_initialized = true); 550 551} 552 553// These are signals that are unblocked while a thread is running Java. 554// (For some reason, they get blocked by default.) 555sigset_t* os::Linux::unblocked_signals() { 556 assert(signal_sets_initialized, "Not initialized"); 557 return &unblocked_sigs; 558} 559 560// These are the signals that are blocked while a (non-VM) thread is 561// running Java. Only the VM thread handles these signals. 562sigset_t* os::Linux::vm_signals() { 563 assert(signal_sets_initialized, "Not initialized"); 564 return &vm_sigs; 565} 566 567// These are signals that are blocked during cond_wait to allow debugger in 568sigset_t* os::Linux::allowdebug_blocked_signals() { 569 assert(signal_sets_initialized, "Not initialized"); 570 return &allowdebug_blocked_sigs; 571} 572 573void os::Linux::hotspot_sigmask(Thread* thread) { 574 575 //Save caller's signal mask before setting VM signal mask 576 sigset_t caller_sigmask; 577 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 578 579 OSThread* osthread = thread->osthread(); 580 osthread->set_caller_sigmask(caller_sigmask); 581 582 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 583 584 if (!ReduceSignalUsage) { 585 if (thread->is_VM_thread()) { 586 // Only the VM thread handles BREAK_SIGNAL ... 587 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 588 } else { 589 // ... all other threads block BREAK_SIGNAL 590 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 591 } 592 } 593} 594 595////////////////////////////////////////////////////////////////////////////// 596// detecting pthread library 597 598void os::Linux::libpthread_init() { 599 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION 600 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a 601 // generic name for earlier versions. 602 // Define macros here so we can build HotSpot on old systems. 603# ifndef _CS_GNU_LIBC_VERSION 604# define _CS_GNU_LIBC_VERSION 2 605# endif 606# ifndef _CS_GNU_LIBPTHREAD_VERSION 607# define _CS_GNU_LIBPTHREAD_VERSION 3 608# endif 609 610 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 611 if (n > 0) { 612 char *str = (char *)malloc(n, mtInternal); 613 confstr(_CS_GNU_LIBC_VERSION, str, n); 614 os::Linux::set_glibc_version(str); 615 } else { 616 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version() 617 static char _gnu_libc_version[32]; 618 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version), 619 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release()); 620 os::Linux::set_glibc_version(_gnu_libc_version); 621 } 622 623 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 624 if (n > 0) { 625 char *str = (char *)malloc(n, mtInternal); 626 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 627 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells 628 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this 629 // is the case. LinuxThreads has a hard limit on max number of threads. 630 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value. 631 // On the other hand, NPTL does not have such a limit, sysconf() 632 // will return -1 and errno is not changed. Check if it is really NPTL. 633 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 && 634 strstr(str, "NPTL") && 635 sysconf(_SC_THREAD_THREADS_MAX) > 0) { 636 free(str); 637 os::Linux::set_libpthread_version("linuxthreads"); 638 } else { 639 os::Linux::set_libpthread_version(str); 640 } 641 } else { 642 // glibc before 2.3.2 only has LinuxThreads. 643 os::Linux::set_libpthread_version("linuxthreads"); 644 } 645 646 if (strstr(libpthread_version(), "NPTL")) { 647 os::Linux::set_is_NPTL(); 648 } else { 649 os::Linux::set_is_LinuxThreads(); 650 } 651 652 // LinuxThreads have two flavors: floating-stack mode, which allows variable 653 // stack size; and fixed-stack mode. NPTL is always floating-stack. 654 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) { 655 os::Linux::set_is_floating_stack(); 656 } 657} 658 659///////////////////////////////////////////////////////////////////////////// 660// thread stack 661 662// Force Linux kernel to expand current thread stack. If "bottom" is close 663// to the stack guard, caller should block all signals. 664// 665// MAP_GROWSDOWN: 666// A special mmap() flag that is used to implement thread stacks. It tells 667// kernel that the memory region should extend downwards when needed. This 668// allows early versions of LinuxThreads to only mmap the first few pages 669// when creating a new thread. Linux kernel will automatically expand thread 670// stack as needed (on page faults). 671// 672// However, because the memory region of a MAP_GROWSDOWN stack can grow on 673// demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 674// region, it's hard to tell if the fault is due to a legitimate stack 675// access or because of reading/writing non-exist memory (e.g. buffer 676// overrun). As a rule, if the fault happens below current stack pointer, 677// Linux kernel does not expand stack, instead a SIGSEGV is sent to the 678// application (see Linux kernel fault.c). 679// 680// This Linux feature can cause SIGSEGV when VM bangs thread stack for 681// stack overflow detection. 682// 683// Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 684// not use this flag. However, the stack of initial thread is not created 685// by pthread, it is still MAP_GROWSDOWN. Also it's possible (though 686// unlikely) that user code can create a thread with MAP_GROWSDOWN stack 687// and then attach the thread to JVM. 688// 689// To get around the problem and allow stack banging on Linux, we need to 690// manually expand thread stack after receiving the SIGSEGV. 691// 692// There are two ways to expand thread stack to address "bottom", we used 693// both of them in JVM before 1.5: 694// 1. adjust stack pointer first so that it is below "bottom", and then 695// touch "bottom" 696// 2. mmap() the page in question 697// 698// Now alternate signal stack is gone, it's harder to use 2. For instance, 699// if current sp is already near the lower end of page 101, and we need to 700// call mmap() to map page 100, it is possible that part of the mmap() frame 701// will be placed in page 100. When page 100 is mapped, it is zero-filled. 702// That will destroy the mmap() frame and cause VM to crash. 703// 704// The following code works by adjusting sp first, then accessing the "bottom" 705// page to force a page fault. Linux kernel will then automatically expand the 706// stack mapping. 707// 708// _expand_stack_to() assumes its frame size is less than page size, which 709// should always be true if the function is not inlined. 710 711#if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 712#define NOINLINE 713#else 714#define NOINLINE __attribute__ ((noinline)) 715#endif 716 717static void _expand_stack_to(address bottom) NOINLINE; 718 719static void _expand_stack_to(address bottom) { 720 address sp; 721 size_t size; 722 volatile char *p; 723 724 // Adjust bottom to point to the largest address within the same page, it 725 // gives us a one-page buffer if alloca() allocates slightly more memory. 726 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 727 bottom += os::Linux::page_size() - 1; 728 729 // sp might be slightly above current stack pointer; if that's the case, we 730 // will alloca() a little more space than necessary, which is OK. Don't use 731 // os::current_stack_pointer(), as its result can be slightly below current 732 // stack pointer, causing us to not alloca enough to reach "bottom". 733 sp = (address)&sp; 734 735 if (sp > bottom) { 736 size = sp - bottom; 737 p = (volatile char *)alloca(size); 738 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 739 p[0] = '\0'; 740 } 741} 742 743bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 744 assert(t!=NULL, "just checking"); 745 assert(t->osthread()->expanding_stack(), "expand should be set"); 746 assert(t->stack_base() != NULL, "stack_base was not initialized"); 747 748 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 749 sigset_t mask_all, old_sigset; 750 sigfillset(&mask_all); 751 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 752 _expand_stack_to(addr); 753 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 754 return true; 755 } 756 return false; 757} 758 759////////////////////////////////////////////////////////////////////////////// 760// create new thread 761 762static address highest_vm_reserved_address(); 763 764// check if it's safe to start a new thread 765static bool _thread_safety_check(Thread* thread) { 766 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) { 767 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat) 768 // Heap is mmap'ed at lower end of memory space. Thread stacks are 769 // allocated (MAP_FIXED) from high address space. Every thread stack 770 // occupies a fixed size slot (usually 2Mbytes, but user can change 771 // it to other values if they rebuild LinuxThreads). 772 // 773 // Problem with MAP_FIXED is that mmap() can still succeed even part of 774 // the memory region has already been mmap'ed. That means if we have too 775 // many threads and/or very large heap, eventually thread stack will 776 // collide with heap. 777 // 778 // Here we try to prevent heap/stack collision by comparing current 779 // stack bottom with the highest address that has been mmap'ed by JVM 780 // plus a safety margin for memory maps created by native code. 781 // 782 // This feature can be disabled by setting ThreadSafetyMargin to 0 783 // 784 if (ThreadSafetyMargin > 0) { 785 address stack_bottom = os::current_stack_base() - os::current_stack_size(); 786 787 // not safe if our stack extends below the safety margin 788 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address(); 789 } else { 790 return true; 791 } 792 } else { 793 // Floating stack LinuxThreads or NPTL: 794 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When 795 // there's not enough space left, pthread_create() will fail. If we come 796 // here, that means enough space has been reserved for stack. 797 return true; 798 } 799} 800 801// Thread start routine for all newly created threads 802static void *java_start(Thread *thread) { 803 // Try to randomize the cache line index of hot stack frames. 804 // This helps when threads of the same stack traces evict each other's 805 // cache lines. The threads can be either from the same JVM instance, or 806 // from different JVM instances. The benefit is especially true for 807 // processors with hyperthreading technology. 808 static int counter = 0; 809 int pid = os::current_process_id(); 810 alloca(((pid ^ counter++) & 7) * 128); 811 812 ThreadLocalStorage::set_thread(thread); 813 814 OSThread* osthread = thread->osthread(); 815 Monitor* sync = osthread->startThread_lock(); 816 817 // non floating stack LinuxThreads needs extra check, see above 818 if (!_thread_safety_check(thread)) { 819 // notify parent thread 820 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 821 osthread->set_state(ZOMBIE); 822 sync->notify_all(); 823 return NULL; 824 } 825 826 // thread_id is kernel thread id (similar to Solaris LWP id) 827 osthread->set_thread_id(os::Linux::gettid()); 828 829 if (UseNUMA) { 830 int lgrp_id = os::numa_get_group_id(); 831 if (lgrp_id != -1) { 832 thread->set_lgrp_id(lgrp_id); 833 } 834 } 835 // initialize signal mask for this thread 836 os::Linux::hotspot_sigmask(thread); 837 838 // initialize floating point control register 839 os::Linux::init_thread_fpu_state(); 840 841 // handshaking with parent thread 842 { 843 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 844 845 // notify parent thread 846 osthread->set_state(INITIALIZED); 847 sync->notify_all(); 848 849 // wait until os::start_thread() 850 while (osthread->get_state() == INITIALIZED) { 851 sync->wait(Mutex::_no_safepoint_check_flag); 852 } 853 } 854 855 // call one more level start routine 856 thread->run(); 857 858 return 0; 859} 860 861bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) { 862 assert(thread->osthread() == NULL, "caller responsible"); 863 864 // Allocate the OSThread object 865 OSThread* osthread = new OSThread(NULL, NULL); 866 if (osthread == NULL) { 867 return false; 868 } 869 870 // set the correct thread state 871 osthread->set_thread_type(thr_type); 872 873 // Initial state is ALLOCATED but not INITIALIZED 874 osthread->set_state(ALLOCATED); 875 876 thread->set_osthread(osthread); 877 878 // init thread attributes 879 pthread_attr_t attr; 880 pthread_attr_init(&attr); 881 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 882 883 // stack size 884 if (os::Linux::supports_variable_stack_size()) { 885 // calculate stack size if it's not specified by caller 886 if (stack_size == 0) { 887 stack_size = os::Linux::default_stack_size(thr_type); 888 889 switch (thr_type) { 890 case os::java_thread: 891 // Java threads use ThreadStackSize which default value can be 892 // changed with the flag -Xss 893 assert (JavaThread::stack_size_at_create() > 0, "this should be set"); 894 stack_size = JavaThread::stack_size_at_create(); 895 break; 896 case os::compiler_thread: 897 if (CompilerThreadStackSize > 0) { 898 stack_size = (size_t)(CompilerThreadStackSize * K); 899 break; 900 } // else fall through: 901 // use VMThreadStackSize if CompilerThreadStackSize is not defined 902 case os::vm_thread: 903 case os::pgc_thread: 904 case os::cgc_thread: 905 case os::watcher_thread: 906 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 907 break; 908 } 909 } 910 911 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 912 pthread_attr_setstacksize(&attr, stack_size); 913 } else { 914 // let pthread_create() pick the default value. 915 } 916 917 // glibc guard page 918 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 919 920 ThreadState state; 921 922 { 923 // Serialize thread creation if we are running with fixed stack LinuxThreads 924 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack(); 925 if (lock) { 926 os::Linux::createThread_lock()->lock_without_safepoint_check(); 927 } 928 929 pthread_t tid; 930 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 931 932 pthread_attr_destroy(&attr); 933 934 if (ret != 0) { 935 if (PrintMiscellaneous && (Verbose || WizardMode)) { 936 perror("pthread_create()"); 937 } 938 // Need to clean up stuff we've allocated so far 939 thread->set_osthread(NULL); 940 delete osthread; 941 if (lock) os::Linux::createThread_lock()->unlock(); 942 return false; 943 } 944 945 // Store pthread info into the OSThread 946 osthread->set_pthread_id(tid); 947 948 // Wait until child thread is either initialized or aborted 949 { 950 Monitor* sync_with_child = osthread->startThread_lock(); 951 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 952 while ((state = osthread->get_state()) == ALLOCATED) { 953 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 954 } 955 } 956 957 if (lock) { 958 os::Linux::createThread_lock()->unlock(); 959 } 960 } 961 962 // Aborted due to thread limit being reached 963 if (state == ZOMBIE) { 964 thread->set_osthread(NULL); 965 delete osthread; 966 return false; 967 } 968 969 // The thread is returned suspended (in state INITIALIZED), 970 // and is started higher up in the call chain 971 assert(state == INITIALIZED, "race condition"); 972 return true; 973} 974 975///////////////////////////////////////////////////////////////////////////// 976// attach existing thread 977 978// bootstrap the main thread 979bool os::create_main_thread(JavaThread* thread) { 980 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 981 return create_attached_thread(thread); 982} 983 984bool os::create_attached_thread(JavaThread* thread) { 985#ifdef ASSERT 986 thread->verify_not_published(); 987#endif 988 989 // Allocate the OSThread object 990 OSThread* osthread = new OSThread(NULL, NULL); 991 992 if (osthread == NULL) { 993 return false; 994 } 995 996 // Store pthread info into the OSThread 997 osthread->set_thread_id(os::Linux::gettid()); 998 osthread->set_pthread_id(::pthread_self()); 999 1000 // initialize floating point control register 1001 os::Linux::init_thread_fpu_state(); 1002 1003 // Initial thread state is RUNNABLE 1004 osthread->set_state(RUNNABLE); 1005 1006 thread->set_osthread(osthread); 1007 1008 if (UseNUMA) { 1009 int lgrp_id = os::numa_get_group_id(); 1010 if (lgrp_id != -1) { 1011 thread->set_lgrp_id(lgrp_id); 1012 } 1013 } 1014 1015 if (os::Linux::is_initial_thread()) { 1016 // If current thread is initial thread, its stack is mapped on demand, 1017 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 1018 // the entire stack region to avoid SEGV in stack banging. 1019 // It is also useful to get around the heap-stack-gap problem on SuSE 1020 // kernel (see 4821821 for details). We first expand stack to the top 1021 // of yellow zone, then enable stack yellow zone (order is significant, 1022 // enabling yellow zone first will crash JVM on SuSE Linux), so there 1023 // is no gap between the last two virtual memory regions. 1024 1025 JavaThread *jt = (JavaThread *)thread; 1026 address addr = jt->stack_yellow_zone_base(); 1027 assert(addr != NULL, "initialization problem?"); 1028 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 1029 1030 osthread->set_expanding_stack(); 1031 os::Linux::manually_expand_stack(jt, addr); 1032 osthread->clear_expanding_stack(); 1033 } 1034 1035 // initialize signal mask for this thread 1036 // and save the caller's signal mask 1037 os::Linux::hotspot_sigmask(thread); 1038 1039 return true; 1040} 1041 1042void os::pd_start_thread(Thread* thread) { 1043 OSThread * osthread = thread->osthread(); 1044 assert(osthread->get_state() != INITIALIZED, "just checking"); 1045 Monitor* sync_with_child = osthread->startThread_lock(); 1046 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 1047 sync_with_child->notify(); 1048} 1049 1050// Free Linux resources related to the OSThread 1051void os::free_thread(OSThread* osthread) { 1052 assert(osthread != NULL, "osthread not set"); 1053 1054 if (Thread::current()->osthread() == osthread) { 1055 // Restore caller's signal mask 1056 sigset_t sigmask = osthread->caller_sigmask(); 1057 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1058 } 1059 1060 delete osthread; 1061} 1062 1063////////////////////////////////////////////////////////////////////////////// 1064// thread local storage 1065 1066int os::allocate_thread_local_storage() { 1067 pthread_key_t key; 1068 int rslt = pthread_key_create(&key, NULL); 1069 assert(rslt == 0, "cannot allocate thread local storage"); 1070 return (int)key; 1071} 1072 1073// Note: This is currently not used by VM, as we don't destroy TLS key 1074// on VM exit. 1075void os::free_thread_local_storage(int index) { 1076 int rslt = pthread_key_delete((pthread_key_t)index); 1077 assert(rslt == 0, "invalid index"); 1078} 1079 1080void os::thread_local_storage_at_put(int index, void* value) { 1081 int rslt = pthread_setspecific((pthread_key_t)index, value); 1082 assert(rslt == 0, "pthread_setspecific failed"); 1083} 1084 1085extern "C" Thread* get_thread() { 1086 return ThreadLocalStorage::thread(); 1087} 1088 1089////////////////////////////////////////////////////////////////////////////// 1090// initial thread 1091 1092// Check if current thread is the initial thread, similar to Solaris thr_main. 1093bool os::Linux::is_initial_thread(void) { 1094 char dummy; 1095 // If called before init complete, thread stack bottom will be null. 1096 // Can be called if fatal error occurs before initialization. 1097 if (initial_thread_stack_bottom() == NULL) return false; 1098 assert(initial_thread_stack_bottom() != NULL && 1099 initial_thread_stack_size() != 0, 1100 "os::init did not locate initial thread's stack region"); 1101 if ((address)&dummy >= initial_thread_stack_bottom() && 1102 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) 1103 return true; 1104 else return false; 1105} 1106 1107// Find the virtual memory area that contains addr 1108static bool find_vma(address addr, address* vma_low, address* vma_high) { 1109 FILE *fp = fopen("/proc/self/maps", "r"); 1110 if (fp) { 1111 address low, high; 1112 while (!feof(fp)) { 1113 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1114 if (low <= addr && addr < high) { 1115 if (vma_low) *vma_low = low; 1116 if (vma_high) *vma_high = high; 1117 fclose (fp); 1118 return true; 1119 } 1120 } 1121 for (;;) { 1122 int ch = fgetc(fp); 1123 if (ch == EOF || ch == (int)'\n') break; 1124 } 1125 } 1126 fclose(fp); 1127 } 1128 return false; 1129} 1130 1131// Locate initial thread stack. This special handling of initial thread stack 1132// is needed because pthread_getattr_np() on most (all?) Linux distros returns 1133// bogus value for initial thread. 1134void os::Linux::capture_initial_stack(size_t max_size) { 1135 // stack size is the easy part, get it from RLIMIT_STACK 1136 size_t stack_size; 1137 struct rlimit rlim; 1138 getrlimit(RLIMIT_STACK, &rlim); 1139 stack_size = rlim.rlim_cur; 1140 1141 // 6308388: a bug in ld.so will relocate its own .data section to the 1142 // lower end of primordial stack; reduce ulimit -s value a little bit 1143 // so we won't install guard page on ld.so's data section. 1144 stack_size -= 2 * page_size(); 1145 1146 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 1147 // 7.1, in both cases we will get 2G in return value. 1148 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 1149 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 1150 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 1151 // in case other parts in glibc still assumes 2M max stack size. 1152 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 1153 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 1154 if (stack_size > 2 * K * K IA64_ONLY(*2)) 1155 stack_size = 2 * K * K IA64_ONLY(*2); 1156 // Try to figure out where the stack base (top) is. This is harder. 1157 // 1158 // When an application is started, glibc saves the initial stack pointer in 1159 // a global variable "__libc_stack_end", which is then used by system 1160 // libraries. __libc_stack_end should be pretty close to stack top. The 1161 // variable is available since the very early days. However, because it is 1162 // a private interface, it could disappear in the future. 1163 // 1164 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1165 // to __libc_stack_end, it is very close to stack top, but isn't the real 1166 // stack top. Note that /proc may not exist if VM is running as a chroot 1167 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1168 // /proc/<pid>/stat could change in the future (though unlikely). 1169 // 1170 // We try __libc_stack_end first. If that doesn't work, look for 1171 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1172 // as a hint, which should work well in most cases. 1173 1174 uintptr_t stack_start; 1175 1176 // try __libc_stack_end first 1177 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1178 if (p && *p) { 1179 stack_start = *p; 1180 } else { 1181 // see if we can get the start_stack field from /proc/self/stat 1182 FILE *fp; 1183 int pid; 1184 char state; 1185 int ppid; 1186 int pgrp; 1187 int session; 1188 int nr; 1189 int tpgrp; 1190 unsigned long flags; 1191 unsigned long minflt; 1192 unsigned long cminflt; 1193 unsigned long majflt; 1194 unsigned long cmajflt; 1195 unsigned long utime; 1196 unsigned long stime; 1197 long cutime; 1198 long cstime; 1199 long prio; 1200 long nice; 1201 long junk; 1202 long it_real; 1203 uintptr_t start; 1204 uintptr_t vsize; 1205 intptr_t rss; 1206 uintptr_t rsslim; 1207 uintptr_t scodes; 1208 uintptr_t ecode; 1209 int i; 1210 1211 // Figure what the primordial thread stack base is. Code is inspired 1212 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1213 // followed by command name surrounded by parentheses, state, etc. 1214 char stat[2048]; 1215 int statlen; 1216 1217 fp = fopen("/proc/self/stat", "r"); 1218 if (fp) { 1219 statlen = fread(stat, 1, 2047, fp); 1220 stat[statlen] = '\0'; 1221 fclose(fp); 1222 1223 // Skip pid and the command string. Note that we could be dealing with 1224 // weird command names, e.g. user could decide to rename java launcher 1225 // to "java 1.4.2 :)", then the stat file would look like 1226 // 1234 (java 1.4.2 :)) R ... ... 1227 // We don't really need to know the command string, just find the last 1228 // occurrence of ")" and then start parsing from there. See bug 4726580. 1229 char * s = strrchr(stat, ')'); 1230 1231 i = 0; 1232 if (s) { 1233 // Skip blank chars 1234 do s++; while (isspace(*s)); 1235 1236#define _UFM UINTX_FORMAT 1237#define _DFM INTX_FORMAT 1238 1239 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */ 1240 /* 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 */ 1241 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, 1242 &state, /* 3 %c */ 1243 &ppid, /* 4 %d */ 1244 &pgrp, /* 5 %d */ 1245 &session, /* 6 %d */ 1246 &nr, /* 7 %d */ 1247 &tpgrp, /* 8 %d */ 1248 &flags, /* 9 %lu */ 1249 &minflt, /* 10 %lu */ 1250 &cminflt, /* 11 %lu */ 1251 &majflt, /* 12 %lu */ 1252 &cmajflt, /* 13 %lu */ 1253 &utime, /* 14 %lu */ 1254 &stime, /* 15 %lu */ 1255 &cutime, /* 16 %ld */ 1256 &cstime, /* 17 %ld */ 1257 &prio, /* 18 %ld */ 1258 &nice, /* 19 %ld */ 1259 &junk, /* 20 %ld */ 1260 &it_real, /* 21 %ld */ 1261 &start, /* 22 UINTX_FORMAT */ 1262 &vsize, /* 23 UINTX_FORMAT */ 1263 &rss, /* 24 INTX_FORMAT */ 1264 &rsslim, /* 25 UINTX_FORMAT */ 1265 &scodes, /* 26 UINTX_FORMAT */ 1266 &ecode, /* 27 UINTX_FORMAT */ 1267 &stack_start); /* 28 UINTX_FORMAT */ 1268 } 1269 1270#undef _UFM 1271#undef _DFM 1272 1273 if (i != 28 - 2) { 1274 assert(false, "Bad conversion from /proc/self/stat"); 1275 // product mode - assume we are the initial thread, good luck in the 1276 // embedded case. 1277 warning("Can't detect initial thread stack location - bad conversion"); 1278 stack_start = (uintptr_t) &rlim; 1279 } 1280 } else { 1281 // For some reason we can't open /proc/self/stat (for example, running on 1282 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1283 // most cases, so don't abort: 1284 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1285 stack_start = (uintptr_t) &rlim; 1286 } 1287 } 1288 1289 // Now we have a pointer (stack_start) very close to the stack top, the 1290 // next thing to do is to figure out the exact location of stack top. We 1291 // can find out the virtual memory area that contains stack_start by 1292 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1293 // and its upper limit is the real stack top. (again, this would fail if 1294 // running inside chroot, because /proc may not exist.) 1295 1296 uintptr_t stack_top; 1297 address low, high; 1298 if (find_vma((address)stack_start, &low, &high)) { 1299 // success, "high" is the true stack top. (ignore "low", because initial 1300 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1301 stack_top = (uintptr_t)high; 1302 } else { 1303 // failed, likely because /proc/self/maps does not exist 1304 warning("Can't detect initial thread stack location - find_vma failed"); 1305 // best effort: stack_start is normally within a few pages below the real 1306 // stack top, use it as stack top, and reduce stack size so we won't put 1307 // guard page outside stack. 1308 stack_top = stack_start; 1309 stack_size -= 16 * page_size(); 1310 } 1311 1312 // stack_top could be partially down the page so align it 1313 stack_top = align_size_up(stack_top, page_size()); 1314 1315 if (max_size && stack_size > max_size) { 1316 _initial_thread_stack_size = max_size; 1317 } else { 1318 _initial_thread_stack_size = stack_size; 1319 } 1320 1321 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1322 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1323} 1324 1325//////////////////////////////////////////////////////////////////////////////// 1326// time support 1327 1328// Time since start-up in seconds to a fine granularity. 1329// Used by VMSelfDestructTimer and the MemProfiler. 1330double os::elapsedTime() { 1331 1332 return (double)(os::elapsed_counter()) * 0.000001; 1333} 1334 1335jlong os::elapsed_counter() { 1336 timeval time; 1337 int status = gettimeofday(&time, NULL); 1338 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count; 1339} 1340 1341jlong os::elapsed_frequency() { 1342 return (1000 * 1000); 1343} 1344 1345bool os::supports_vtime() { return true; } 1346bool os::enable_vtime() { return false; } 1347bool os::vtime_enabled() { return false; } 1348 1349double os::elapsedVTime() { 1350 struct rusage usage; 1351 int retval = getrusage(RUSAGE_THREAD, &usage); 1352 if (retval == 0) { 1353 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000); 1354 } else { 1355 // better than nothing, but not much 1356 return elapsedTime(); 1357 } 1358} 1359 1360jlong os::javaTimeMillis() { 1361 timeval time; 1362 int status = gettimeofday(&time, NULL); 1363 assert(status != -1, "linux error"); 1364 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1365} 1366 1367#ifndef CLOCK_MONOTONIC 1368#define CLOCK_MONOTONIC (1) 1369#endif 1370 1371void os::Linux::clock_init() { 1372 // we do dlopen's in this particular order due to bug in linux 1373 // dynamical loader (see 6348968) leading to crash on exit 1374 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1375 if (handle == NULL) { 1376 handle = dlopen("librt.so", RTLD_LAZY); 1377 } 1378 1379 if (handle) { 1380 int (*clock_getres_func)(clockid_t, struct timespec*) = 1381 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1382 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1383 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1384 if (clock_getres_func && clock_gettime_func) { 1385 // See if monotonic clock is supported by the kernel. Note that some 1386 // early implementations simply return kernel jiffies (updated every 1387 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1388 // for nano time (though the monotonic property is still nice to have). 1389 // It's fixed in newer kernels, however clock_getres() still returns 1390 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1391 // resolution for now. Hopefully as people move to new kernels, this 1392 // won't be a problem. 1393 struct timespec res; 1394 struct timespec tp; 1395 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1396 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1397 // yes, monotonic clock is supported 1398 _clock_gettime = clock_gettime_func; 1399 } else { 1400 // close librt if there is no monotonic clock 1401 dlclose(handle); 1402 } 1403 } 1404 } 1405} 1406 1407#ifndef SYS_clock_getres 1408 1409#if defined(IA32) || defined(AMD64) 1410#define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1411#define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1412#else 1413#warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1414#define sys_clock_getres(x,y) -1 1415#endif 1416 1417#else 1418#define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1419#endif 1420 1421void os::Linux::fast_thread_clock_init() { 1422 if (!UseLinuxPosixThreadCPUClocks) { 1423 return; 1424 } 1425 clockid_t clockid; 1426 struct timespec tp; 1427 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1428 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1429 1430 // Switch to using fast clocks for thread cpu time if 1431 // the sys_clock_getres() returns 0 error code. 1432 // Note, that some kernels may support the current thread 1433 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1434 // returned by the pthread_getcpuclockid(). 1435 // If the fast Posix clocks are supported then the sys_clock_getres() 1436 // must return at least tp.tv_sec == 0 which means a resolution 1437 // better than 1 sec. This is extra check for reliability. 1438 1439 if(pthread_getcpuclockid_func && 1440 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1441 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1442 1443 _supports_fast_thread_cpu_time = true; 1444 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1445 } 1446} 1447 1448jlong os::javaTimeNanos() { 1449 if (Linux::supports_monotonic_clock()) { 1450 struct timespec tp; 1451 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1452 assert(status == 0, "gettime error"); 1453 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1454 return result; 1455 } else { 1456 timeval time; 1457 int status = gettimeofday(&time, NULL); 1458 assert(status != -1, "linux error"); 1459 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1460 return 1000 * usecs; 1461 } 1462} 1463 1464void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1465 if (Linux::supports_monotonic_clock()) { 1466 info_ptr->max_value = ALL_64_BITS; 1467 1468 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1469 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1470 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1471 } else { 1472 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1473 info_ptr->max_value = ALL_64_BITS; 1474 1475 // gettimeofday is a real time clock so it skips 1476 info_ptr->may_skip_backward = true; 1477 info_ptr->may_skip_forward = true; 1478 } 1479 1480 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1481} 1482 1483// Return the real, user, and system times in seconds from an 1484// arbitrary fixed point in the past. 1485bool os::getTimesSecs(double* process_real_time, 1486 double* process_user_time, 1487 double* process_system_time) { 1488 struct tms ticks; 1489 clock_t real_ticks = times(&ticks); 1490 1491 if (real_ticks == (clock_t) (-1)) { 1492 return false; 1493 } else { 1494 double ticks_per_second = (double) clock_tics_per_sec; 1495 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1496 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1497 *process_real_time = ((double) real_ticks) / ticks_per_second; 1498 1499 return true; 1500 } 1501} 1502 1503 1504char * os::local_time_string(char *buf, size_t buflen) { 1505 struct tm t; 1506 time_t long_time; 1507 time(&long_time); 1508 localtime_r(&long_time, &t); 1509 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1510 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1511 t.tm_hour, t.tm_min, t.tm_sec); 1512 return buf; 1513} 1514 1515struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1516 return localtime_r(clock, res); 1517} 1518 1519//////////////////////////////////////////////////////////////////////////////// 1520// runtime exit support 1521 1522// Note: os::shutdown() might be called very early during initialization, or 1523// called from signal handler. Before adding something to os::shutdown(), make 1524// sure it is async-safe and can handle partially initialized VM. 1525void os::shutdown() { 1526 1527 // allow PerfMemory to attempt cleanup of any persistent resources 1528 perfMemory_exit(); 1529 1530 // needs to remove object in file system 1531 AttachListener::abort(); 1532 1533 // flush buffered output, finish log files 1534 ostream_abort(); 1535 1536 // Check for abort hook 1537 abort_hook_t abort_hook = Arguments::abort_hook(); 1538 if (abort_hook != NULL) { 1539 abort_hook(); 1540 } 1541 1542} 1543 1544// Note: os::abort() might be called very early during initialization, or 1545// called from signal handler. Before adding something to os::abort(), make 1546// sure it is async-safe and can handle partially initialized VM. 1547void os::abort(bool dump_core) { 1548 os::shutdown(); 1549 if (dump_core) { 1550#ifndef PRODUCT 1551 fdStream out(defaultStream::output_fd()); 1552 out.print_raw("Current thread is "); 1553 char buf[16]; 1554 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1555 out.print_raw_cr(buf); 1556 out.print_raw_cr("Dumping core ..."); 1557#endif 1558 ::abort(); // dump core 1559 } 1560 1561 ::exit(1); 1562} 1563 1564// Die immediately, no exit hook, no abort hook, no cleanup. 1565void os::die() { 1566 // _exit() on LinuxThreads only kills current thread 1567 ::abort(); 1568} 1569 1570// unused on linux for now. 1571void os::set_error_file(const char *logfile) {} 1572 1573 1574// This method is a copy of JDK's sysGetLastErrorString 1575// from src/solaris/hpi/src/system_md.c 1576 1577size_t os::lasterror(char *buf, size_t len) { 1578 1579 if (errno == 0) return 0; 1580 1581 const char *s = ::strerror(errno); 1582 size_t n = ::strlen(s); 1583 if (n >= len) { 1584 n = len - 1; 1585 } 1586 ::strncpy(buf, s, n); 1587 buf[n] = '\0'; 1588 return n; 1589} 1590 1591intx os::current_thread_id() { return (intx)pthread_self(); } 1592int os::current_process_id() { 1593 1594 // Under the old linux thread library, linux gives each thread 1595 // its own process id. Because of this each thread will return 1596 // a different pid if this method were to return the result 1597 // of getpid(2). Linux provides no api that returns the pid 1598 // of the launcher thread for the vm. This implementation 1599 // returns a unique pid, the pid of the launcher thread 1600 // that starts the vm 'process'. 1601 1602 // Under the NPTL, getpid() returns the same pid as the 1603 // launcher thread rather than a unique pid per thread. 1604 // Use gettid() if you want the old pre NPTL behaviour. 1605 1606 // if you are looking for the result of a call to getpid() that 1607 // returns a unique pid for the calling thread, then look at the 1608 // OSThread::thread_id() method in osThread_linux.hpp file 1609 1610 return (int)(_initial_pid ? _initial_pid : getpid()); 1611} 1612 1613// DLL functions 1614 1615const char* os::dll_file_extension() { return ".so"; } 1616 1617// This must be hard coded because it's the system's temporary 1618// directory not the java application's temp directory, ala java.io.tmpdir. 1619const char* os::get_temp_directory() { return "/tmp"; } 1620 1621static bool file_exists(const char* filename) { 1622 struct stat statbuf; 1623 if (filename == NULL || strlen(filename) == 0) { 1624 return false; 1625 } 1626 return os::stat(filename, &statbuf) == 0; 1627} 1628 1629bool os::dll_build_name(char* buffer, size_t buflen, 1630 const char* pname, const char* fname) { 1631 bool retval = false; 1632 // Copied from libhpi 1633 const size_t pnamelen = pname ? strlen(pname) : 0; 1634 1635 // Return error on buffer overflow. 1636 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1637 return retval; 1638 } 1639 1640 if (pnamelen == 0) { 1641 snprintf(buffer, buflen, "lib%s.so", fname); 1642 retval = true; 1643 } else if (strchr(pname, *os::path_separator()) != NULL) { 1644 int n; 1645 char** pelements = split_path(pname, &n); 1646 if (pelements == NULL) { 1647 return false; 1648 } 1649 for (int i = 0 ; i < n ; i++) { 1650 // Really shouldn't be NULL, but check can't hurt 1651 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1652 continue; // skip the empty path values 1653 } 1654 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1655 if (file_exists(buffer)) { 1656 retval = true; 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], mtInternal); 1664 } 1665 } 1666 if (pelements != NULL) { 1667 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal); 1668 } 1669 } else { 1670 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1671 retval = true; 1672 } 1673 return retval; 1674} 1675 1676// check if addr is inside libjvm.so 1677bool os::address_is_in_vm(address addr) { 1678 static address libjvm_base_addr; 1679 Dl_info dlinfo; 1680 1681 if (libjvm_base_addr == NULL) { 1682 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo); 1683 libjvm_base_addr = (address)dlinfo.dli_fbase; 1684 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1685 } 1686 1687 if (dladdr((void *)addr, &dlinfo)) { 1688 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1689 } 1690 1691 return false; 1692} 1693 1694bool os::dll_address_to_function_name(address addr, char *buf, 1695 int buflen, int *offset) { 1696 Dl_info dlinfo; 1697 1698 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) { 1699 if (buf != NULL) { 1700 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) { 1701 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1702 } 1703 } 1704 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1705 return true; 1706 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) { 1707 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1708 buf, buflen, offset, dlinfo.dli_fname)) { 1709 return true; 1710 } 1711 } 1712 1713 if (buf != NULL) buf[0] = '\0'; 1714 if (offset != NULL) *offset = -1; 1715 return false; 1716} 1717 1718struct _address_to_library_name { 1719 address addr; // input : memory address 1720 size_t buflen; // size of fname 1721 char* fname; // output: library name 1722 address base; // library base addr 1723}; 1724 1725static int address_to_library_name_callback(struct dl_phdr_info *info, 1726 size_t size, void *data) { 1727 int i; 1728 bool found = false; 1729 address libbase = NULL; 1730 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1731 1732 // iterate through all loadable segments 1733 for (i = 0; i < info->dlpi_phnum; i++) { 1734 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1735 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1736 // base address of a library is the lowest address of its loaded 1737 // segments. 1738 if (libbase == NULL || libbase > segbase) { 1739 libbase = segbase; 1740 } 1741 // see if 'addr' is within current segment 1742 if (segbase <= d->addr && 1743 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1744 found = true; 1745 } 1746 } 1747 } 1748 1749 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1750 // so dll_address_to_library_name() can fall through to use dladdr() which 1751 // can figure out executable name from argv[0]. 1752 if (found && info->dlpi_name && info->dlpi_name[0]) { 1753 d->base = libbase; 1754 if (d->fname) { 1755 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1756 } 1757 return 1; 1758 } 1759 return 0; 1760} 1761 1762bool os::dll_address_to_library_name(address addr, char* buf, 1763 int buflen, int* offset) { 1764 Dl_info dlinfo; 1765 struct _address_to_library_name data; 1766 1767 // There is a bug in old glibc dladdr() implementation that it could resolve 1768 // to wrong library name if the .so file has a base address != NULL. Here 1769 // we iterate through the program headers of all loaded libraries to find 1770 // out which library 'addr' really belongs to. This workaround can be 1771 // removed once the minimum requirement for glibc is moved to 2.3.x. 1772 data.addr = addr; 1773 data.fname = buf; 1774 data.buflen = buflen; 1775 data.base = NULL; 1776 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1777 1778 if (rslt) { 1779 // buf already contains library name 1780 if (offset) *offset = addr - data.base; 1781 return true; 1782 } else if (dladdr((void*)addr, &dlinfo)){ 1783 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1784 if (offset) *offset = addr - (address)dlinfo.dli_fbase; 1785 return true; 1786 } else { 1787 if (buf) buf[0] = '\0'; 1788 if (offset) *offset = -1; 1789 return false; 1790 } 1791} 1792 1793 // Loads .dll/.so and 1794 // in case of error it checks if .dll/.so was built for the 1795 // same architecture as Hotspot is running on 1796 1797 1798// Remember the stack's state. The Linux dynamic linker will change 1799// the stack to 'executable' at most once, so we must safepoint only once. 1800bool os::Linux::_stack_is_executable = false; 1801 1802// VM operation that loads a library. This is necessary if stack protection 1803// of the Java stacks can be lost during loading the library. If we 1804// do not stop the Java threads, they can stack overflow before the stacks 1805// are protected again. 1806class VM_LinuxDllLoad: public VM_Operation { 1807 private: 1808 const char *_filename; 1809 char *_ebuf; 1810 int _ebuflen; 1811 void *_lib; 1812 public: 1813 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1814 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1815 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1816 void doit() { 1817 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1818 os::Linux::_stack_is_executable = true; 1819 } 1820 void* loaded_library() { return _lib; } 1821}; 1822 1823void * os::dll_load(const char *filename, char *ebuf, int ebuflen) 1824{ 1825 void * result = NULL; 1826 bool load_attempted = false; 1827 1828 // Check whether the library to load might change execution rights 1829 // of the stack. If they are changed, the protection of the stack 1830 // guard pages will be lost. We need a safepoint to fix this. 1831 // 1832 // See Linux man page execstack(8) for more info. 1833 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1834 ElfFile ef(filename); 1835 if (!ef.specifies_noexecstack()) { 1836 if (!is_init_completed()) { 1837 os::Linux::_stack_is_executable = true; 1838 // This is OK - No Java threads have been created yet, and hence no 1839 // stack guard pages to fix. 1840 // 1841 // This should happen only when you are building JDK7 using a very 1842 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1843 // 1844 // Dynamic loader will make all stacks executable after 1845 // this function returns, and will not do that again. 1846 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1847 } else { 1848 warning("You have loaded library %s which might have disabled stack guard. " 1849 "The VM will try to fix the stack guard now.\n" 1850 "It's highly recommended that you fix the library with " 1851 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1852 filename); 1853 1854 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1855 JavaThread *jt = JavaThread::current(); 1856 if (jt->thread_state() != _thread_in_native) { 1857 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1858 // that requires ExecStack. Cannot enter safe point. Let's give up. 1859 warning("Unable to fix stack guard. Giving up."); 1860 } else { 1861 if (!LoadExecStackDllInVMThread) { 1862 // This is for the case where the DLL has an static 1863 // constructor function that executes JNI code. We cannot 1864 // load such DLLs in the VMThread. 1865 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1866 } 1867 1868 ThreadInVMfromNative tiv(jt); 1869 debug_only(VMNativeEntryWrapper vew;) 1870 1871 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1872 VMThread::execute(&op); 1873 if (LoadExecStackDllInVMThread) { 1874 result = op.loaded_library(); 1875 } 1876 load_attempted = true; 1877 } 1878 } 1879 } 1880 } 1881 1882 if (!load_attempted) { 1883 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1884 } 1885 1886 if (result != NULL) { 1887 // Successful loading 1888 return result; 1889 } 1890 1891 Elf32_Ehdr elf_head; 1892 int diag_msg_max_length=ebuflen-strlen(ebuf); 1893 char* diag_msg_buf=ebuf+strlen(ebuf); 1894 1895 if (diag_msg_max_length==0) { 1896 // No more space in ebuf for additional diagnostics message 1897 return NULL; 1898 } 1899 1900 1901 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1902 1903 if (file_descriptor < 0) { 1904 // Can't open library, report dlerror() message 1905 return NULL; 1906 } 1907 1908 bool failed_to_read_elf_head= 1909 (sizeof(elf_head)!= 1910 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ; 1911 1912 ::close(file_descriptor); 1913 if (failed_to_read_elf_head) { 1914 // file i/o error - report dlerror() msg 1915 return NULL; 1916 } 1917 1918 typedef struct { 1919 Elf32_Half code; // Actual value as defined in elf.h 1920 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1921 char elf_class; // 32 or 64 bit 1922 char endianess; // MSB or LSB 1923 char* name; // String representation 1924 } arch_t; 1925 1926 #ifndef EM_486 1927 #define EM_486 6 /* Intel 80486 */ 1928 #endif 1929 1930 static const arch_t arch_array[]={ 1931 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1932 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1933 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1934 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1935 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1936 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1937 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1938 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1939 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1940 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1941 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1942 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1943 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1944 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1945 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1946 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"} 1947 }; 1948 1949 #if (defined IA32) 1950 static Elf32_Half running_arch_code=EM_386; 1951 #elif (defined AMD64) 1952 static Elf32_Half running_arch_code=EM_X86_64; 1953 #elif (defined IA64) 1954 static Elf32_Half running_arch_code=EM_IA_64; 1955 #elif (defined __sparc) && (defined _LP64) 1956 static Elf32_Half running_arch_code=EM_SPARCV9; 1957 #elif (defined __sparc) && (!defined _LP64) 1958 static Elf32_Half running_arch_code=EM_SPARC; 1959 #elif (defined __powerpc64__) 1960 static Elf32_Half running_arch_code=EM_PPC64; 1961 #elif (defined __powerpc__) 1962 static Elf32_Half running_arch_code=EM_PPC; 1963 #elif (defined ARM) 1964 static Elf32_Half running_arch_code=EM_ARM; 1965 #elif (defined S390) 1966 static Elf32_Half running_arch_code=EM_S390; 1967 #elif (defined ALPHA) 1968 static Elf32_Half running_arch_code=EM_ALPHA; 1969 #elif (defined MIPSEL) 1970 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1971 #elif (defined PARISC) 1972 static Elf32_Half running_arch_code=EM_PARISC; 1973 #elif (defined MIPS) 1974 static Elf32_Half running_arch_code=EM_MIPS; 1975 #elif (defined M68K) 1976 static Elf32_Half running_arch_code=EM_68K; 1977 #else 1978 #error Method os::dll_load requires that one of following is defined:\ 1979 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K 1980 #endif 1981 1982 // Identify compatability class for VM's architecture and library's architecture 1983 // Obtain string descriptions for architectures 1984 1985 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1986 int running_arch_index=-1; 1987 1988 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) { 1989 if (running_arch_code == arch_array[i].code) { 1990 running_arch_index = i; 1991 } 1992 if (lib_arch.code == arch_array[i].code) { 1993 lib_arch.compat_class = arch_array[i].compat_class; 1994 lib_arch.name = arch_array[i].name; 1995 } 1996 } 1997 1998 assert(running_arch_index != -1, 1999 "Didn't find running architecture code (running_arch_code) in arch_array"); 2000 if (running_arch_index == -1) { 2001 // Even though running architecture detection failed 2002 // we may still continue with reporting dlerror() message 2003 return NULL; 2004 } 2005 2006 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 2007 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 2008 return NULL; 2009 } 2010 2011#ifndef S390 2012 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 2013 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 2014 return NULL; 2015 } 2016#endif // !S390 2017 2018 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 2019 if ( lib_arch.name!=NULL ) { 2020 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 2021 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 2022 lib_arch.name, arch_array[running_arch_index].name); 2023 } else { 2024 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 2025 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 2026 lib_arch.code, 2027 arch_array[running_arch_index].name); 2028 } 2029 } 2030 2031 return NULL; 2032} 2033 2034void * os::Linux::dlopen_helper(const char *filename, char *ebuf, int ebuflen) { 2035 void * result = ::dlopen(filename, RTLD_LAZY); 2036 if (result == NULL) { 2037 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 2038 ebuf[ebuflen-1] = '\0'; 2039 } 2040 return result; 2041} 2042 2043void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, int ebuflen) { 2044 void * result = NULL; 2045 if (LoadExecStackDllInVMThread) { 2046 result = dlopen_helper(filename, ebuf, ebuflen); 2047 } 2048 2049 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 2050 // library that requires an executable stack, or which does not have this 2051 // stack attribute set, dlopen changes the stack attribute to executable. The 2052 // read protection of the guard pages gets lost. 2053 // 2054 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 2055 // may have been queued at the same time. 2056 2057 if (!_stack_is_executable) { 2058 JavaThread *jt = Threads::first(); 2059 2060 while (jt) { 2061 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 2062 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions 2063 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(), 2064 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) { 2065 warning("Attempt to reguard stack yellow zone failed."); 2066 } 2067 } 2068 jt = jt->next(); 2069 } 2070 } 2071 2072 return result; 2073} 2074 2075/* 2076 * glibc-2.0 libdl is not MT safe. If you are building with any glibc, 2077 * chances are you might want to run the generated bits against glibc-2.0 2078 * libdl.so, so always use locking for any version of glibc. 2079 */ 2080void* os::dll_lookup(void* handle, const char* name) { 2081 pthread_mutex_lock(&dl_mutex); 2082 void* res = dlsym(handle, name); 2083 pthread_mutex_unlock(&dl_mutex); 2084 return res; 2085} 2086 2087 2088static bool _print_ascii_file(const char* filename, outputStream* st) { 2089 int fd = ::open(filename, O_RDONLY); 2090 if (fd == -1) { 2091 return false; 2092 } 2093 2094 char buf[32]; 2095 int bytes; 2096 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 2097 st->print_raw(buf, bytes); 2098 } 2099 2100 ::close(fd); 2101 2102 return true; 2103} 2104 2105void os::print_dll_info(outputStream *st) { 2106 st->print_cr("Dynamic libraries:"); 2107 2108 char fname[32]; 2109 pid_t pid = os::Linux::gettid(); 2110 2111 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 2112 2113 if (!_print_ascii_file(fname, st)) { 2114 st->print("Can not get library information for pid = %d\n", pid); 2115 } 2116} 2117 2118void os::print_os_info_brief(outputStream* st) { 2119 os::Linux::print_distro_info(st); 2120 2121 os::Posix::print_uname_info(st); 2122 2123 os::Linux::print_libversion_info(st); 2124 2125} 2126 2127void os::print_os_info(outputStream* st) { 2128 st->print("OS:"); 2129 2130 os::Linux::print_distro_info(st); 2131 2132 os::Posix::print_uname_info(st); 2133 2134 // Print warning if unsafe chroot environment detected 2135 if (unsafe_chroot_detected) { 2136 st->print("WARNING!! "); 2137 st->print_cr(unstable_chroot_error); 2138 } 2139 2140 os::Linux::print_libversion_info(st); 2141 2142 os::Posix::print_rlimit_info(st); 2143 2144 os::Posix::print_load_average(st); 2145 2146 os::Linux::print_full_memory_info(st); 2147} 2148 2149// Try to identify popular distros. 2150// Most Linux distributions have /etc/XXX-release file, which contains 2151// the OS version string. Some have more than one /etc/XXX-release file 2152// (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.), 2153// so the order is important. 2154void os::Linux::print_distro_info(outputStream* st) { 2155 if (!_print_ascii_file("/etc/mandrake-release", st) && 2156 !_print_ascii_file("/etc/sun-release", st) && 2157 !_print_ascii_file("/etc/redhat-release", st) && 2158 !_print_ascii_file("/etc/SuSE-release", st) && 2159 !_print_ascii_file("/etc/turbolinux-release", st) && 2160 !_print_ascii_file("/etc/gentoo-release", st) && 2161 !_print_ascii_file("/etc/debian_version", st) && 2162 !_print_ascii_file("/etc/ltib-release", st) && 2163 !_print_ascii_file("/etc/angstrom-version", st)) { 2164 st->print("Linux"); 2165 } 2166 st->cr(); 2167} 2168 2169void os::Linux::print_libversion_info(outputStream* st) { 2170 // libc, pthread 2171 st->print("libc:"); 2172 st->print(os::Linux::glibc_version()); st->print(" "); 2173 st->print(os::Linux::libpthread_version()); st->print(" "); 2174 if (os::Linux::is_LinuxThreads()) { 2175 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed"); 2176 } 2177 st->cr(); 2178} 2179 2180void os::Linux::print_full_memory_info(outputStream* st) { 2181 st->print("\n/proc/meminfo:\n"); 2182 _print_ascii_file("/proc/meminfo", st); 2183 st->cr(); 2184} 2185 2186void os::print_memory_info(outputStream* st) { 2187 2188 st->print("Memory:"); 2189 st->print(" %dk page", os::vm_page_size()>>10); 2190 2191 // values in struct sysinfo are "unsigned long" 2192 struct sysinfo si; 2193 sysinfo(&si); 2194 2195 st->print(", physical " UINT64_FORMAT "k", 2196 os::physical_memory() >> 10); 2197 st->print("(" UINT64_FORMAT "k free)", 2198 os::available_memory() >> 10); 2199 st->print(", swap " UINT64_FORMAT "k", 2200 ((jlong)si.totalswap * si.mem_unit) >> 10); 2201 st->print("(" UINT64_FORMAT "k free)", 2202 ((jlong)si.freeswap * si.mem_unit) >> 10); 2203 st->cr(); 2204} 2205 2206void os::pd_print_cpu_info(outputStream* st) { 2207 st->print("\n/proc/cpuinfo:\n"); 2208 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2209 st->print(" <Not Available>"); 2210 } 2211 st->cr(); 2212} 2213 2214// Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific 2215// but they're the same for all the linux arch that we support 2216// and they're the same for solaris but there's no common place to put this. 2217const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR", 2218 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG", 2219 "ILL_COPROC", "ILL_BADSTK" }; 2220 2221const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV", 2222 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES", 2223 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" }; 2224 2225const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" }; 2226 2227const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" }; 2228 2229void os::print_siginfo(outputStream* st, void* siginfo) { 2230 st->print("siginfo:"); 2231 2232 const int buflen = 100; 2233 char buf[buflen]; 2234 siginfo_t *si = (siginfo_t*)siginfo; 2235 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen)); 2236 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) { 2237 st->print("si_errno=%s", buf); 2238 } else { 2239 st->print("si_errno=%d", si->si_errno); 2240 } 2241 const int c = si->si_code; 2242 assert(c > 0, "unexpected si_code"); 2243 switch (si->si_signo) { 2244 case SIGILL: 2245 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]); 2246 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2247 break; 2248 case SIGFPE: 2249 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]); 2250 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2251 break; 2252 case SIGSEGV: 2253 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]); 2254 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2255 break; 2256 case SIGBUS: 2257 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]); 2258 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2259 break; 2260 default: 2261 st->print(", si_code=%d", si->si_code); 2262 // no si_addr 2263 } 2264 2265 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2266 UseSharedSpaces) { 2267 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2268 if (mapinfo->is_in_shared_space(si->si_addr)) { 2269 st->print("\n\nError accessing class data sharing archive." \ 2270 " Mapped file inaccessible during execution, " \ 2271 " possible disk/network problem."); 2272 } 2273 } 2274 st->cr(); 2275} 2276 2277 2278static void print_signal_handler(outputStream* st, int sig, 2279 char* buf, size_t buflen); 2280 2281void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2282 st->print_cr("Signal Handlers:"); 2283 print_signal_handler(st, SIGSEGV, buf, buflen); 2284 print_signal_handler(st, SIGBUS , buf, buflen); 2285 print_signal_handler(st, SIGFPE , buf, buflen); 2286 print_signal_handler(st, SIGPIPE, buf, buflen); 2287 print_signal_handler(st, SIGXFSZ, buf, buflen); 2288 print_signal_handler(st, SIGILL , buf, buflen); 2289 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2290 print_signal_handler(st, SR_signum, buf, buflen); 2291 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2292 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2293 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2294 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2295} 2296 2297static char saved_jvm_path[MAXPATHLEN] = {0}; 2298 2299// Find the full path to the current module, libjvm.so 2300void os::jvm_path(char *buf, jint buflen) { 2301 // Error checking. 2302 if (buflen < MAXPATHLEN) { 2303 assert(false, "must use a large-enough buffer"); 2304 buf[0] = '\0'; 2305 return; 2306 } 2307 // Lazy resolve the path to current module. 2308 if (saved_jvm_path[0] != 0) { 2309 strcpy(buf, saved_jvm_path); 2310 return; 2311 } 2312 2313 char dli_fname[MAXPATHLEN]; 2314 bool ret = dll_address_to_library_name( 2315 CAST_FROM_FN_PTR(address, os::jvm_path), 2316 dli_fname, sizeof(dli_fname), NULL); 2317 assert(ret != 0, "cannot locate libjvm"); 2318 char *rp = realpath(dli_fname, buf); 2319 if (rp == NULL) 2320 return; 2321 2322 if (Arguments::created_by_gamma_launcher()) { 2323 // Support for the gamma launcher. Typical value for buf is 2324 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at 2325 // the right place in the string, then assume we are installed in a JDK and 2326 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix 2327 // up the path so it looks like libjvm.so is installed there (append a 2328 // fake suffix hotspot/libjvm.so). 2329 const char *p = buf + strlen(buf) - 1; 2330 for (int count = 0; p > buf && count < 5; ++count) { 2331 for (--p; p > buf && *p != '/'; --p) 2332 /* empty */ ; 2333 } 2334 2335 if (strncmp(p, "/jre/lib/", 9) != 0) { 2336 // Look for JAVA_HOME in the environment. 2337 char* java_home_var = ::getenv("JAVA_HOME"); 2338 if (java_home_var != NULL && java_home_var[0] != 0) { 2339 char* jrelib_p; 2340 int len; 2341 2342 // Check the current module name "libjvm.so". 2343 p = strrchr(buf, '/'); 2344 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2345 2346 rp = realpath(java_home_var, buf); 2347 if (rp == NULL) 2348 return; 2349 2350 // determine if this is a legacy image or modules image 2351 // modules image doesn't have "jre" subdirectory 2352 len = strlen(buf); 2353 jrelib_p = buf + len; 2354 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2355 if (0 != access(buf, F_OK)) { 2356 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2357 } 2358 2359 if (0 == access(buf, F_OK)) { 2360 // Use current module name "libjvm.so" 2361 len = strlen(buf); 2362 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2363 } else { 2364 // Go back to path of .so 2365 rp = realpath(dli_fname, buf); 2366 if (rp == NULL) 2367 return; 2368 } 2369 } 2370 } 2371 } 2372 2373 strcpy(saved_jvm_path, buf); 2374} 2375 2376void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2377 // no prefix required, not even "_" 2378} 2379 2380void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2381 // no suffix required 2382} 2383 2384//////////////////////////////////////////////////////////////////////////////// 2385// sun.misc.Signal support 2386 2387static volatile jint sigint_count = 0; 2388 2389static void 2390UserHandler(int sig, void *siginfo, void *context) { 2391 // 4511530 - sem_post is serialized and handled by the manager thread. When 2392 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2393 // don't want to flood the manager thread with sem_post requests. 2394 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) 2395 return; 2396 2397 // Ctrl-C is pressed during error reporting, likely because the error 2398 // handler fails to abort. Let VM die immediately. 2399 if (sig == SIGINT && is_error_reported()) { 2400 os::die(); 2401 } 2402 2403 os::signal_notify(sig); 2404} 2405 2406void* os::user_handler() { 2407 return CAST_FROM_FN_PTR(void*, UserHandler); 2408} 2409 2410extern "C" { 2411 typedef void (*sa_handler_t)(int); 2412 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2413} 2414 2415void* os::signal(int signal_number, void* handler) { 2416 struct sigaction sigAct, oldSigAct; 2417 2418 sigfillset(&(sigAct.sa_mask)); 2419 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2420 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2421 2422 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2423 // -1 means registration failed 2424 return (void *)-1; 2425 } 2426 2427 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2428} 2429 2430void os::signal_raise(int signal_number) { 2431 ::raise(signal_number); 2432} 2433 2434/* 2435 * The following code is moved from os.cpp for making this 2436 * code platform specific, which it is by its very nature. 2437 */ 2438 2439// Will be modified when max signal is changed to be dynamic 2440int os::sigexitnum_pd() { 2441 return NSIG; 2442} 2443 2444// a counter for each possible signal value 2445static volatile jint pending_signals[NSIG+1] = { 0 }; 2446 2447// Linux(POSIX) specific hand shaking semaphore. 2448static sem_t sig_sem; 2449 2450void os::signal_init_pd() { 2451 // Initialize signal structures 2452 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2453 2454 // Initialize signal semaphore 2455 ::sem_init(&sig_sem, 0, 0); 2456} 2457 2458void os::signal_notify(int sig) { 2459 Atomic::inc(&pending_signals[sig]); 2460 ::sem_post(&sig_sem); 2461} 2462 2463static int check_pending_signals(bool wait) { 2464 Atomic::store(0, &sigint_count); 2465 for (;;) { 2466 for (int i = 0; i < NSIG + 1; i++) { 2467 jint n = pending_signals[i]; 2468 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2469 return i; 2470 } 2471 } 2472 if (!wait) { 2473 return -1; 2474 } 2475 JavaThread *thread = JavaThread::current(); 2476 ThreadBlockInVM tbivm(thread); 2477 2478 bool threadIsSuspended; 2479 do { 2480 thread->set_suspend_equivalent(); 2481 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2482 ::sem_wait(&sig_sem); 2483 2484 // were we externally suspended while we were waiting? 2485 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2486 if (threadIsSuspended) { 2487 // 2488 // The semaphore has been incremented, but while we were waiting 2489 // another thread suspended us. We don't want to continue running 2490 // while suspended because that would surprise the thread that 2491 // suspended us. 2492 // 2493 ::sem_post(&sig_sem); 2494 2495 thread->java_suspend_self(); 2496 } 2497 } while (threadIsSuspended); 2498 } 2499} 2500 2501int os::signal_lookup() { 2502 return check_pending_signals(false); 2503} 2504 2505int os::signal_wait() { 2506 return check_pending_signals(true); 2507} 2508 2509//////////////////////////////////////////////////////////////////////////////// 2510// Virtual Memory 2511 2512int os::vm_page_size() { 2513 // Seems redundant as all get out 2514 assert(os::Linux::page_size() != -1, "must call os::init"); 2515 return os::Linux::page_size(); 2516} 2517 2518// Solaris allocates memory by pages. 2519int os::vm_allocation_granularity() { 2520 assert(os::Linux::page_size() != -1, "must call os::init"); 2521 return os::Linux::page_size(); 2522} 2523 2524// Rationale behind this function: 2525// current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2526// mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2527// samples for JITted code. Here we create private executable mapping over the code cache 2528// and then we can use standard (well, almost, as mapping can change) way to provide 2529// info for the reporting script by storing timestamp and location of symbol 2530void linux_wrap_code(char* base, size_t size) { 2531 static volatile jint cnt = 0; 2532 2533 if (!UseOprofile) { 2534 return; 2535 } 2536 2537 char buf[PATH_MAX+1]; 2538 int num = Atomic::add(1, &cnt); 2539 2540 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2541 os::get_temp_directory(), os::current_process_id(), num); 2542 unlink(buf); 2543 2544 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2545 2546 if (fd != -1) { 2547 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2548 if (rv != (off_t)-1) { 2549 if (::write(fd, "", 1) == 1) { 2550 mmap(base, size, 2551 PROT_READ|PROT_WRITE|PROT_EXEC, 2552 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2553 } 2554 } 2555 ::close(fd); 2556 unlink(buf); 2557 } 2558} 2559 2560// NOTE: Linux kernel does not really reserve the pages for us. 2561// All it does is to check if there are enough free pages 2562// left at the time of mmap(). This could be a potential 2563// problem. 2564bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2565 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2566 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2567 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2568 if (res != (uintptr_t) MAP_FAILED) { 2569 if (UseNUMAInterleaving) { 2570 numa_make_global(addr, size); 2571 } 2572 return true; 2573 } 2574 return false; 2575} 2576 2577// Define MAP_HUGETLB here so we can build HotSpot on old systems. 2578#ifndef MAP_HUGETLB 2579#define MAP_HUGETLB 0x40000 2580#endif 2581 2582// Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2583#ifndef MADV_HUGEPAGE 2584#define MADV_HUGEPAGE 14 2585#endif 2586 2587bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2588 bool exec) { 2589 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) { 2590 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2591 uintptr_t res = 2592 (uintptr_t) ::mmap(addr, size, prot, 2593 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB, 2594 -1, 0); 2595 if (res != (uintptr_t) MAP_FAILED) { 2596 if (UseNUMAInterleaving) { 2597 numa_make_global(addr, size); 2598 } 2599 return true; 2600 } 2601 // Fall through and try to use small pages 2602 } 2603 2604 if (commit_memory(addr, size, exec)) { 2605 realign_memory(addr, size, alignment_hint); 2606 return true; 2607 } 2608 return false; 2609} 2610 2611void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2612 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) { 2613 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2614 // be supported or the memory may already be backed by huge pages. 2615 ::madvise(addr, bytes, MADV_HUGEPAGE); 2616 } 2617} 2618 2619void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2620 // This method works by doing an mmap over an existing mmaping and effectively discarding 2621 // the existing pages. However it won't work for SHM-based large pages that cannot be 2622 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2623 // small pages on top of the SHM segment. This method always works for small pages, so we 2624 // allow that in any case. 2625 if (alignment_hint <= (size_t)os::vm_page_size() || !UseSHM) { 2626 commit_memory(addr, bytes, alignment_hint, false); 2627 } 2628} 2629 2630void os::numa_make_global(char *addr, size_t bytes) { 2631 Linux::numa_interleave_memory(addr, bytes); 2632} 2633 2634void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2635 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2636} 2637 2638bool os::numa_topology_changed() { return false; } 2639 2640size_t os::numa_get_groups_num() { 2641 int max_node = Linux::numa_max_node(); 2642 return max_node > 0 ? max_node + 1 : 1; 2643} 2644 2645int os::numa_get_group_id() { 2646 int cpu_id = Linux::sched_getcpu(); 2647 if (cpu_id != -1) { 2648 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2649 if (lgrp_id != -1) { 2650 return lgrp_id; 2651 } 2652 } 2653 return 0; 2654} 2655 2656size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2657 for (size_t i = 0; i < size; i++) { 2658 ids[i] = i; 2659 } 2660 return size; 2661} 2662 2663bool os::get_page_info(char *start, page_info* info) { 2664 return false; 2665} 2666 2667char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) { 2668 return end; 2669} 2670 2671 2672int os::Linux::sched_getcpu_syscall(void) { 2673 unsigned int cpu; 2674 int retval = -1; 2675 2676#if defined(IA32) 2677# ifndef SYS_getcpu 2678# define SYS_getcpu 318 2679# endif 2680 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2681#elif defined(AMD64) 2682// Unfortunately we have to bring all these macros here from vsyscall.h 2683// to be able to compile on old linuxes. 2684# define __NR_vgetcpu 2 2685# define VSYSCALL_START (-10UL << 20) 2686# define VSYSCALL_SIZE 1024 2687# define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2688 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2689 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2690 retval = vgetcpu(&cpu, NULL, NULL); 2691#endif 2692 2693 return (retval == -1) ? retval : cpu; 2694} 2695 2696// Something to do with the numa-aware allocator needs these symbols 2697extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2698extern "C" JNIEXPORT void numa_error(char *where) { } 2699extern "C" JNIEXPORT int fork1() { return fork(); } 2700 2701 2702// If we are running with libnuma version > 2, then we should 2703// be trying to use symbols with versions 1.1 2704// If we are running with earlier version, which did not have symbol versions, 2705// we should use the base version. 2706void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2707 void *f = dlvsym(handle, name, "libnuma_1.1"); 2708 if (f == NULL) { 2709 f = dlsym(handle, name); 2710 } 2711 return f; 2712} 2713 2714bool os::Linux::libnuma_init() { 2715 // sched_getcpu() should be in libc. 2716 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2717 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2718 2719 // If it's not, try a direct syscall. 2720 if (sched_getcpu() == -1) 2721 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall)); 2722 2723 if (sched_getcpu() != -1) { // Does it work? 2724 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2725 if (handle != NULL) { 2726 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2727 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2728 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2729 libnuma_dlsym(handle, "numa_max_node"))); 2730 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2731 libnuma_dlsym(handle, "numa_available"))); 2732 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2733 libnuma_dlsym(handle, "numa_tonode_memory"))); 2734 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2735 libnuma_dlsym(handle, "numa_interleave_memory"))); 2736 2737 2738 if (numa_available() != -1) { 2739 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2740 // Create a cpu -> node mapping 2741 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2742 rebuild_cpu_to_node_map(); 2743 return true; 2744 } 2745 } 2746 } 2747 return false; 2748} 2749 2750// rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2751// The table is later used in get_node_by_cpu(). 2752void os::Linux::rebuild_cpu_to_node_map() { 2753 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2754 // in libnuma (possible values are starting from 16, 2755 // and continuing up with every other power of 2, but less 2756 // than the maximum number of CPUs supported by kernel), and 2757 // is a subject to change (in libnuma version 2 the requirements 2758 // are more reasonable) we'll just hardcode the number they use 2759 // in the library. 2760 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2761 2762 size_t cpu_num = os::active_processor_count(); 2763 size_t cpu_map_size = NCPUS / BitsPerCLong; 2764 size_t cpu_map_valid_size = 2765 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2766 2767 cpu_to_node()->clear(); 2768 cpu_to_node()->at_grow(cpu_num - 1); 2769 size_t node_num = numa_get_groups_num(); 2770 2771 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2772 for (size_t i = 0; i < node_num; i++) { 2773 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2774 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2775 if (cpu_map[j] != 0) { 2776 for (size_t k = 0; k < BitsPerCLong; k++) { 2777 if (cpu_map[j] & (1UL << k)) { 2778 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2779 } 2780 } 2781 } 2782 } 2783 } 2784 } 2785 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal); 2786} 2787 2788int os::Linux::get_node_by_cpu(int cpu_id) { 2789 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2790 return cpu_to_node()->at(cpu_id); 2791 } 2792 return -1; 2793} 2794 2795GrowableArray<int>* os::Linux::_cpu_to_node; 2796os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2797os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2798os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2799os::Linux::numa_available_func_t os::Linux::_numa_available; 2800os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2801os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2802unsigned long* os::Linux::_numa_all_nodes; 2803 2804bool os::pd_uncommit_memory(char* addr, size_t size) { 2805 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2806 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2807 return res != (uintptr_t) MAP_FAILED; 2808} 2809 2810// Linux uses a growable mapping for the stack, and if the mapping for 2811// the stack guard pages is not removed when we detach a thread the 2812// stack cannot grow beyond the pages where the stack guard was 2813// mapped. If at some point later in the process the stack expands to 2814// that point, the Linux kernel cannot expand the stack any further 2815// because the guard pages are in the way, and a segfault occurs. 2816// 2817// However, it's essential not to split the stack region by unmapping 2818// a region (leaving a hole) that's already part of the stack mapping, 2819// so if the stack mapping has already grown beyond the guard pages at 2820// the time we create them, we have to truncate the stack mapping. 2821// So, we need to know the extent of the stack mapping when 2822// create_stack_guard_pages() is called. 2823 2824// Find the bounds of the stack mapping. Return true for success. 2825// 2826// We only need this for stacks that are growable: at the time of 2827// writing thread stacks don't use growable mappings (i.e. those 2828// creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2829// only applies to the main thread. 2830 2831static 2832bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) { 2833 2834 char buf[128]; 2835 int fd, sz; 2836 2837 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) { 2838 return false; 2839 } 2840 2841 const char kw[] = "[stack]"; 2842 const int kwlen = sizeof(kw)-1; 2843 2844 // Address part of /proc/self/maps couldn't be more than 128 bytes 2845 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) { 2846 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) { 2847 // Extract addresses 2848 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) { 2849 uintptr_t sp = (uintptr_t) __builtin_frame_address(0); 2850 if (sp >= *bottom && sp <= *top) { 2851 ::close(fd); 2852 return true; 2853 } 2854 } 2855 } 2856 } 2857 2858 ::close(fd); 2859 return false; 2860} 2861 2862 2863// If the (growable) stack mapping already extends beyond the point 2864// where we're going to put our guard pages, truncate the mapping at 2865// that point by munmap()ping it. This ensures that when we later 2866// munmap() the guard pages we don't leave a hole in the stack 2867// mapping. This only affects the main/initial thread, but guard 2868// against future OS changes 2869bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 2870 uintptr_t stack_extent, stack_base; 2871 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2872 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2873 assert(os::Linux::is_initial_thread(), 2874 "growable stack in non-initial thread"); 2875 if (stack_extent < (uintptr_t)addr) 2876 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent); 2877 } 2878 2879 return os::commit_memory(addr, size); 2880} 2881 2882// If this is a growable mapping, remove the guard pages entirely by 2883// munmap()ping them. If not, just call uncommit_memory(). This only 2884// affects the main/initial thread, but guard against future OS changes 2885bool os::remove_stack_guard_pages(char* addr, size_t size) { 2886 uintptr_t stack_extent, stack_base; 2887 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2888 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2889 assert(os::Linux::is_initial_thread(), 2890 "growable stack in non-initial thread"); 2891 2892 return ::munmap(addr, size) == 0; 2893 } 2894 2895 return os::uncommit_memory(addr, size); 2896} 2897 2898static address _highest_vm_reserved_address = NULL; 2899 2900// If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 2901// at 'requested_addr'. If there are existing memory mappings at the same 2902// location, however, they will be overwritten. If 'fixed' is false, 2903// 'requested_addr' is only treated as a hint, the return value may or 2904// may not start from the requested address. Unlike Linux mmap(), this 2905// function returns NULL to indicate failure. 2906static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 2907 char * addr; 2908 int flags; 2909 2910 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 2911 if (fixed) { 2912 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 2913 flags |= MAP_FIXED; 2914 } 2915 2916 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 2917 // touch an uncommitted page. Otherwise, the read/write might 2918 // succeed if we have enough swap space to back the physical page. 2919 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 2920 flags, -1, 0); 2921 2922 if (addr != MAP_FAILED) { 2923 // anon_mmap() should only get called during VM initialization, 2924 // don't need lock (actually we can skip locking even it can be called 2925 // from multiple threads, because _highest_vm_reserved_address is just a 2926 // hint about the upper limit of non-stack memory regions.) 2927 if ((address)addr + bytes > _highest_vm_reserved_address) { 2928 _highest_vm_reserved_address = (address)addr + bytes; 2929 } 2930 } 2931 2932 return addr == MAP_FAILED ? NULL : addr; 2933} 2934 2935// Don't update _highest_vm_reserved_address, because there might be memory 2936// regions above addr + size. If so, releasing a memory region only creates 2937// a hole in the address space, it doesn't help prevent heap-stack collision. 2938// 2939static int anon_munmap(char * addr, size_t size) { 2940 return ::munmap(addr, size) == 0; 2941} 2942 2943char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 2944 size_t alignment_hint) { 2945 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 2946} 2947 2948bool os::pd_release_memory(char* addr, size_t size) { 2949 return anon_munmap(addr, size); 2950} 2951 2952static address highest_vm_reserved_address() { 2953 return _highest_vm_reserved_address; 2954} 2955 2956static bool linux_mprotect(char* addr, size_t size, int prot) { 2957 // Linux wants the mprotect address argument to be page aligned. 2958 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 2959 2960 // According to SUSv3, mprotect() should only be used with mappings 2961 // established by mmap(), and mmap() always maps whole pages. Unaligned 2962 // 'addr' likely indicates problem in the VM (e.g. trying to change 2963 // protection of malloc'ed or statically allocated memory). Check the 2964 // caller if you hit this assert. 2965 assert(addr == bottom, "sanity check"); 2966 2967 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 2968 return ::mprotect(bottom, size, prot) == 0; 2969} 2970 2971// Set protections specified 2972bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 2973 bool is_committed) { 2974 unsigned int p = 0; 2975 switch (prot) { 2976 case MEM_PROT_NONE: p = PROT_NONE; break; 2977 case MEM_PROT_READ: p = PROT_READ; break; 2978 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 2979 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 2980 default: 2981 ShouldNotReachHere(); 2982 } 2983 // is_committed is unused. 2984 return linux_mprotect(addr, bytes, p); 2985} 2986 2987bool os::guard_memory(char* addr, size_t size) { 2988 return linux_mprotect(addr, size, PROT_NONE); 2989} 2990 2991bool os::unguard_memory(char* addr, size_t size) { 2992 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 2993} 2994 2995bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 2996 bool result = false; 2997 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE, 2998 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 2999 -1, 0); 3000 3001 if (p != (void *) -1) { 3002 // We don't know if this really is a huge page or not. 3003 FILE *fp = fopen("/proc/self/maps", "r"); 3004 if (fp) { 3005 while (!feof(fp)) { 3006 char chars[257]; 3007 long x = 0; 3008 if (fgets(chars, sizeof(chars), fp)) { 3009 if (sscanf(chars, "%lx-%*x", &x) == 1 3010 && x == (long)p) { 3011 if (strstr (chars, "hugepage")) { 3012 result = true; 3013 break; 3014 } 3015 } 3016 } 3017 } 3018 fclose(fp); 3019 } 3020 munmap (p, page_size); 3021 if (result) 3022 return true; 3023 } 3024 3025 if (warn) { 3026 warning("HugeTLBFS is not supported by the operating system."); 3027 } 3028 3029 return result; 3030} 3031 3032/* 3033* Set the coredump_filter bits to include largepages in core dump (bit 6) 3034* 3035* From the coredump_filter documentation: 3036* 3037* - (bit 0) anonymous private memory 3038* - (bit 1) anonymous shared memory 3039* - (bit 2) file-backed private memory 3040* - (bit 3) file-backed shared memory 3041* - (bit 4) ELF header pages in file-backed private memory areas (it is 3042* effective only if the bit 2 is cleared) 3043* - (bit 5) hugetlb private memory 3044* - (bit 6) hugetlb shared memory 3045*/ 3046static void set_coredump_filter(void) { 3047 FILE *f; 3048 long cdm; 3049 3050 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3051 return; 3052 } 3053 3054 if (fscanf(f, "%lx", &cdm) != 1) { 3055 fclose(f); 3056 return; 3057 } 3058 3059 rewind(f); 3060 3061 if ((cdm & LARGEPAGES_BIT) == 0) { 3062 cdm |= LARGEPAGES_BIT; 3063 fprintf(f, "%#lx", cdm); 3064 } 3065 3066 fclose(f); 3067} 3068 3069// Large page support 3070 3071static size_t _large_page_size = 0; 3072 3073void os::large_page_init() { 3074 if (!UseLargePages) { 3075 UseHugeTLBFS = false; 3076 UseSHM = false; 3077 return; 3078 } 3079 3080 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) { 3081 // If UseLargePages is specified on the command line try both methods, 3082 // if it's default, then try only HugeTLBFS. 3083 if (FLAG_IS_DEFAULT(UseLargePages)) { 3084 UseHugeTLBFS = true; 3085 } else { 3086 UseHugeTLBFS = UseSHM = true; 3087 } 3088 } 3089 3090 if (LargePageSizeInBytes) { 3091 _large_page_size = LargePageSizeInBytes; 3092 } else { 3093 // large_page_size on Linux is used to round up heap size. x86 uses either 3094 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3095 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3096 // page as large as 256M. 3097 // 3098 // Here we try to figure out page size by parsing /proc/meminfo and looking 3099 // for a line with the following format: 3100 // Hugepagesize: 2048 kB 3101 // 3102 // If we can't determine the value (e.g. /proc is not mounted, or the text 3103 // format has been changed), we'll use the largest page size supported by 3104 // the processor. 3105 3106#ifndef ZERO 3107 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3108 ARM_ONLY(2 * M) PPC_ONLY(4 * M); 3109#endif // ZERO 3110 3111 FILE *fp = fopen("/proc/meminfo", "r"); 3112 if (fp) { 3113 while (!feof(fp)) { 3114 int x = 0; 3115 char buf[16]; 3116 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3117 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3118 _large_page_size = x * K; 3119 break; 3120 } 3121 } else { 3122 // skip to next line 3123 for (;;) { 3124 int ch = fgetc(fp); 3125 if (ch == EOF || ch == (int)'\n') break; 3126 } 3127 } 3128 } 3129 fclose(fp); 3130 } 3131 } 3132 3133 // print a warning if any large page related flag is specified on command line 3134 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3135 3136 const size_t default_page_size = (size_t)Linux::page_size(); 3137 if (_large_page_size > default_page_size) { 3138 _page_sizes[0] = _large_page_size; 3139 _page_sizes[1] = default_page_size; 3140 _page_sizes[2] = 0; 3141 } 3142 UseHugeTLBFS = UseHugeTLBFS && 3143 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size); 3144 3145 if (UseHugeTLBFS) 3146 UseSHM = false; 3147 3148 UseLargePages = UseHugeTLBFS || UseSHM; 3149 3150 set_coredump_filter(); 3151} 3152 3153#ifndef SHM_HUGETLB 3154#define SHM_HUGETLB 04000 3155#endif 3156 3157char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) { 3158 // "exec" is passed in but not used. Creating the shared image for 3159 // the code cache doesn't have an SHM_X executable permission to check. 3160 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3161 3162 key_t key = IPC_PRIVATE; 3163 char *addr; 3164 3165 bool warn_on_failure = UseLargePages && 3166 (!FLAG_IS_DEFAULT(UseLargePages) || 3167 !FLAG_IS_DEFAULT(LargePageSizeInBytes) 3168 ); 3169 char msg[128]; 3170 3171 // Create a large shared memory region to attach to based on size. 3172 // Currently, size is the total size of the heap 3173 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3174 if (shmid == -1) { 3175 // Possible reasons for shmget failure: 3176 // 1. shmmax is too small for Java heap. 3177 // > check shmmax value: cat /proc/sys/kernel/shmmax 3178 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3179 // 2. not enough large page memory. 3180 // > check available large pages: cat /proc/meminfo 3181 // > increase amount of large pages: 3182 // echo new_value > /proc/sys/vm/nr_hugepages 3183 // Note 1: different Linux may use different name for this property, 3184 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3185 // Note 2: it's possible there's enough physical memory available but 3186 // they are so fragmented after a long run that they can't 3187 // coalesce into large pages. Try to reserve large pages when 3188 // the system is still "fresh". 3189 if (warn_on_failure) { 3190 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3191 warning(msg); 3192 } 3193 return NULL; 3194 } 3195 3196 // attach to the region 3197 addr = (char*)shmat(shmid, req_addr, 0); 3198 int err = errno; 3199 3200 // Remove shmid. If shmat() is successful, the actual shared memory segment 3201 // will be deleted when it's detached by shmdt() or when the process 3202 // terminates. If shmat() is not successful this will remove the shared 3203 // segment immediately. 3204 shmctl(shmid, IPC_RMID, NULL); 3205 3206 if ((intptr_t)addr == -1) { 3207 if (warn_on_failure) { 3208 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3209 warning(msg); 3210 } 3211 return NULL; 3212 } 3213 3214 if ((addr != NULL) && UseNUMAInterleaving) { 3215 numa_make_global(addr, bytes); 3216 } 3217 3218 // The memory is committed 3219 address pc = CALLER_PC; 3220 MemTracker::record_virtual_memory_reserve((address)addr, bytes, pc); 3221 MemTracker::record_virtual_memory_commit((address)addr, bytes, pc); 3222 3223 return addr; 3224} 3225 3226bool os::release_memory_special(char* base, size_t bytes) { 3227 // detaching the SHM segment will also delete it, see reserve_memory_special() 3228 int rslt = shmdt(base); 3229 if (rslt == 0) { 3230 MemTracker::record_virtual_memory_uncommit((address)base, bytes); 3231 MemTracker::record_virtual_memory_release((address)base, bytes); 3232 return true; 3233 } else { 3234 return false; 3235 } 3236} 3237 3238size_t os::large_page_size() { 3239 return _large_page_size; 3240} 3241 3242// HugeTLBFS allows application to commit large page memory on demand; 3243// with SysV SHM the entire memory region must be allocated as shared 3244// memory. 3245bool os::can_commit_large_page_memory() { 3246 return UseHugeTLBFS; 3247} 3248 3249bool os::can_execute_large_page_memory() { 3250 return UseHugeTLBFS; 3251} 3252 3253// Reserve memory at an arbitrary address, only if that area is 3254// available (and not reserved for something else). 3255 3256char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3257 const int max_tries = 10; 3258 char* base[max_tries]; 3259 size_t size[max_tries]; 3260 const size_t gap = 0x000000; 3261 3262 // Assert only that the size is a multiple of the page size, since 3263 // that's all that mmap requires, and since that's all we really know 3264 // about at this low abstraction level. If we need higher alignment, 3265 // we can either pass an alignment to this method or verify alignment 3266 // in one of the methods further up the call chain. See bug 5044738. 3267 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3268 3269 // Repeatedly allocate blocks until the block is allocated at the 3270 // right spot. Give up after max_tries. Note that reserve_memory() will 3271 // automatically update _highest_vm_reserved_address if the call is 3272 // successful. The variable tracks the highest memory address every reserved 3273 // by JVM. It is used to detect heap-stack collision if running with 3274 // fixed-stack LinuxThreads. Because here we may attempt to reserve more 3275 // space than needed, it could confuse the collision detecting code. To 3276 // solve the problem, save current _highest_vm_reserved_address and 3277 // calculate the correct value before return. 3278 address old_highest = _highest_vm_reserved_address; 3279 3280 // Linux mmap allows caller to pass an address as hint; give it a try first, 3281 // if kernel honors the hint then we can return immediately. 3282 char * addr = anon_mmap(requested_addr, bytes, false); 3283 if (addr == requested_addr) { 3284 return requested_addr; 3285 } 3286 3287 if (addr != NULL) { 3288 // mmap() is successful but it fails to reserve at the requested address 3289 anon_munmap(addr, bytes); 3290 } 3291 3292 int i; 3293 for (i = 0; i < max_tries; ++i) { 3294 base[i] = reserve_memory(bytes); 3295 3296 if (base[i] != NULL) { 3297 // Is this the block we wanted? 3298 if (base[i] == requested_addr) { 3299 size[i] = bytes; 3300 break; 3301 } 3302 3303 // Does this overlap the block we wanted? Give back the overlapped 3304 // parts and try again. 3305 3306 size_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3307 if (top_overlap >= 0 && top_overlap < bytes) { 3308 unmap_memory(base[i], top_overlap); 3309 base[i] += top_overlap; 3310 size[i] = bytes - top_overlap; 3311 } else { 3312 size_t bottom_overlap = base[i] + bytes - requested_addr; 3313 if (bottom_overlap >= 0 && bottom_overlap < bytes) { 3314 unmap_memory(requested_addr, bottom_overlap); 3315 size[i] = bytes - bottom_overlap; 3316 } else { 3317 size[i] = bytes; 3318 } 3319 } 3320 } 3321 } 3322 3323 // Give back the unused reserved pieces. 3324 3325 for (int j = 0; j < i; ++j) { 3326 if (base[j] != NULL) { 3327 unmap_memory(base[j], size[j]); 3328 } 3329 } 3330 3331 if (i < max_tries) { 3332 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes); 3333 return requested_addr; 3334 } else { 3335 _highest_vm_reserved_address = old_highest; 3336 return NULL; 3337 } 3338} 3339 3340size_t os::read(int fd, void *buf, unsigned int nBytes) { 3341 return ::read(fd, buf, nBytes); 3342} 3343 3344// TODO-FIXME: reconcile Solaris' os::sleep with the linux variation. 3345// Solaris uses poll(), linux uses park(). 3346// Poll() is likely a better choice, assuming that Thread.interrupt() 3347// generates a SIGUSRx signal. Note that SIGUSR1 can interfere with 3348// SIGSEGV, see 4355769. 3349 3350int os::sleep(Thread* thread, jlong millis, bool interruptible) { 3351 assert(thread == Thread::current(), "thread consistency check"); 3352 3353 ParkEvent * const slp = thread->_SleepEvent ; 3354 slp->reset() ; 3355 OrderAccess::fence() ; 3356 3357 if (interruptible) { 3358 jlong prevtime = javaTimeNanos(); 3359 3360 for (;;) { 3361 if (os::is_interrupted(thread, true)) { 3362 return OS_INTRPT; 3363 } 3364 3365 jlong newtime = javaTimeNanos(); 3366 3367 if (newtime - prevtime < 0) { 3368 // time moving backwards, should only happen if no monotonic clock 3369 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3370 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3371 } else { 3372 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 3373 } 3374 3375 if(millis <= 0) { 3376 return OS_OK; 3377 } 3378 3379 prevtime = newtime; 3380 3381 { 3382 assert(thread->is_Java_thread(), "sanity check"); 3383 JavaThread *jt = (JavaThread *) thread; 3384 ThreadBlockInVM tbivm(jt); 3385 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 3386 3387 jt->set_suspend_equivalent(); 3388 // cleared by handle_special_suspend_equivalent_condition() or 3389 // java_suspend_self() via check_and_wait_while_suspended() 3390 3391 slp->park(millis); 3392 3393 // were we externally suspended while we were waiting? 3394 jt->check_and_wait_while_suspended(); 3395 } 3396 } 3397 } else { 3398 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 3399 jlong prevtime = javaTimeNanos(); 3400 3401 for (;;) { 3402 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 3403 // the 1st iteration ... 3404 jlong newtime = javaTimeNanos(); 3405 3406 if (newtime - prevtime < 0) { 3407 // time moving backwards, should only happen if no monotonic clock 3408 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3409 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3410 } else { 3411 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 3412 } 3413 3414 if(millis <= 0) break ; 3415 3416 prevtime = newtime; 3417 slp->park(millis); 3418 } 3419 return OS_OK ; 3420 } 3421} 3422 3423int os::naked_sleep() { 3424 // %% make the sleep time an integer flag. for now use 1 millisec. 3425 return os::sleep(Thread::current(), 1, false); 3426} 3427 3428// Sleep forever; naked call to OS-specific sleep; use with CAUTION 3429void os::infinite_sleep() { 3430 while (true) { // sleep forever ... 3431 ::sleep(100); // ... 100 seconds at a time 3432 } 3433} 3434 3435// Used to convert frequent JVM_Yield() to nops 3436bool os::dont_yield() { 3437 return DontYieldALot; 3438} 3439 3440void os::yield() { 3441 sched_yield(); 3442} 3443 3444os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;} 3445 3446void os::yield_all(int attempts) { 3447 // Yields to all threads, including threads with lower priorities 3448 // Threads on Linux are all with same priority. The Solaris style 3449 // os::yield_all() with nanosleep(1ms) is not necessary. 3450 sched_yield(); 3451} 3452 3453// Called from the tight loops to possibly influence time-sharing heuristics 3454void os::loop_breaker(int attempts) { 3455 os::yield_all(attempts); 3456} 3457 3458//////////////////////////////////////////////////////////////////////////////// 3459// thread priority support 3460 3461// Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3462// only supports dynamic priority, static priority must be zero. For real-time 3463// applications, Linux supports SCHED_RR which allows static priority (1-99). 3464// However, for large multi-threaded applications, SCHED_RR is not only slower 3465// than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3466// of 5 runs - Sep 2005). 3467// 3468// The following code actually changes the niceness of kernel-thread/LWP. It 3469// has an assumption that setpriority() only modifies one kernel-thread/LWP, 3470// not the entire user process, and user level threads are 1:1 mapped to kernel 3471// threads. It has always been the case, but could change in the future. For 3472// this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3473// It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3474 3475int os::java_to_os_priority[CriticalPriority + 1] = { 3476 19, // 0 Entry should never be used 3477 3478 4, // 1 MinPriority 3479 3, // 2 3480 2, // 3 3481 3482 1, // 4 3483 0, // 5 NormPriority 3484 -1, // 6 3485 3486 -2, // 7 3487 -3, // 8 3488 -4, // 9 NearMaxPriority 3489 3490 -5, // 10 MaxPriority 3491 3492 -5 // 11 CriticalPriority 3493}; 3494 3495static int prio_init() { 3496 if (ThreadPriorityPolicy == 1) { 3497 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3498 // if effective uid is not root. Perhaps, a more elegant way of doing 3499 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3500 if (geteuid() != 0) { 3501 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3502 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3503 } 3504 ThreadPriorityPolicy = 0; 3505 } 3506 } 3507 if (UseCriticalJavaThreadPriority) { 3508 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3509 } 3510 return 0; 3511} 3512 3513OSReturn os::set_native_priority(Thread* thread, int newpri) { 3514 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK; 3515 3516 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3517 return (ret == 0) ? OS_OK : OS_ERR; 3518} 3519 3520OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) { 3521 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) { 3522 *priority_ptr = java_to_os_priority[NormPriority]; 3523 return OS_OK; 3524 } 3525 3526 errno = 0; 3527 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3528 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3529} 3530 3531// Hint to the underlying OS that a task switch would not be good. 3532// Void return because it's a hint and can fail. 3533void os::hint_no_preempt() {} 3534 3535//////////////////////////////////////////////////////////////////////////////// 3536// suspend/resume support 3537 3538// the low-level signal-based suspend/resume support is a remnant from the 3539// old VM-suspension that used to be for java-suspension, safepoints etc, 3540// within hotspot. Now there is a single use-case for this: 3541// - calling get_thread_pc() on the VMThread by the flat-profiler task 3542// that runs in the watcher thread. 3543// The remaining code is greatly simplified from the more general suspension 3544// code that used to be used. 3545// 3546// The protocol is quite simple: 3547// - suspend: 3548// - sends a signal to the target thread 3549// - polls the suspend state of the osthread using a yield loop 3550// - target thread signal handler (SR_handler) sets suspend state 3551// and blocks in sigsuspend until continued 3552// - resume: 3553// - sets target osthread state to continue 3554// - sends signal to end the sigsuspend loop in the SR_handler 3555// 3556// Note that the SR_lock plays no role in this suspend/resume protocol. 3557// 3558 3559static void resume_clear_context(OSThread *osthread) { 3560 osthread->set_ucontext(NULL); 3561 osthread->set_siginfo(NULL); 3562 3563 // notify the suspend action is completed, we have now resumed 3564 osthread->sr.clear_suspended(); 3565} 3566 3567static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) { 3568 osthread->set_ucontext(context); 3569 osthread->set_siginfo(siginfo); 3570} 3571 3572// 3573// Handler function invoked when a thread's execution is suspended or 3574// resumed. We have to be careful that only async-safe functions are 3575// called here (Note: most pthread functions are not async safe and 3576// should be avoided.) 3577// 3578// Note: sigwait() is a more natural fit than sigsuspend() from an 3579// interface point of view, but sigwait() prevents the signal hander 3580// from being run. libpthread would get very confused by not having 3581// its signal handlers run and prevents sigwait()'s use with the 3582// mutex granting granting signal. 3583// 3584// Currently only ever called on the VMThread 3585// 3586static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3587 // Save and restore errno to avoid confusing native code with EINTR 3588 // after sigsuspend. 3589 int old_errno = errno; 3590 3591 Thread* thread = Thread::current(); 3592 OSThread* osthread = thread->osthread(); 3593 assert(thread->is_VM_thread(), "Must be VMThread"); 3594 // read current suspend action 3595 int action = osthread->sr.suspend_action(); 3596 if (action == os::Linux::SuspendResume::SR_SUSPEND) { 3597 suspend_save_context(osthread, siginfo, context); 3598 3599 // Notify the suspend action is about to be completed. do_suspend() 3600 // waits until SR_SUSPENDED is set and then returns. We will wait 3601 // here for a resume signal and that completes the suspend-other 3602 // action. do_suspend/do_resume is always called as a pair from 3603 // the same thread - so there are no races 3604 3605 // notify the caller 3606 osthread->sr.set_suspended(); 3607 3608 sigset_t suspend_set; // signals for sigsuspend() 3609 3610 // get current set of blocked signals and unblock resume signal 3611 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3612 sigdelset(&suspend_set, SR_signum); 3613 3614 // wait here until we are resumed 3615 do { 3616 sigsuspend(&suspend_set); 3617 // ignore all returns until we get a resume signal 3618 } while (osthread->sr.suspend_action() != os::Linux::SuspendResume::SR_CONTINUE); 3619 3620 resume_clear_context(osthread); 3621 3622 } else { 3623 assert(action == os::Linux::SuspendResume::SR_CONTINUE, "unexpected sr action"); 3624 // nothing special to do - just leave the handler 3625 } 3626 3627 errno = old_errno; 3628} 3629 3630 3631static int SR_initialize() { 3632 struct sigaction act; 3633 char *s; 3634 /* Get signal number to use for suspend/resume */ 3635 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3636 int sig = ::strtol(s, 0, 10); 3637 if (sig > 0 || sig < _NSIG) { 3638 SR_signum = sig; 3639 } 3640 } 3641 3642 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 3643 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 3644 3645 sigemptyset(&SR_sigset); 3646 sigaddset(&SR_sigset, SR_signum); 3647 3648 /* Set up signal handler for suspend/resume */ 3649 act.sa_flags = SA_RESTART|SA_SIGINFO; 3650 act.sa_handler = (void (*)(int)) SR_handler; 3651 3652 // SR_signum is blocked by default. 3653 // 4528190 - We also need to block pthread restart signal (32 on all 3654 // supported Linux platforms). Note that LinuxThreads need to block 3655 // this signal for all threads to work properly. So we don't have 3656 // to use hard-coded signal number when setting up the mask. 3657 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 3658 3659 if (sigaction(SR_signum, &act, 0) == -1) { 3660 return -1; 3661 } 3662 3663 // Save signal flag 3664 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 3665 return 0; 3666} 3667 3668 3669// returns true on success and false on error - really an error is fatal 3670// but this seems the normal response to library errors 3671static bool do_suspend(OSThread* osthread) { 3672 // mark as suspended and send signal 3673 osthread->sr.set_suspend_action(os::Linux::SuspendResume::SR_SUSPEND); 3674 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3675 assert_status(status == 0, status, "pthread_kill"); 3676 3677 // check status and wait until notified of suspension 3678 if (status == 0) { 3679 for (int i = 0; !osthread->sr.is_suspended(); i++) { 3680 os::yield_all(i); 3681 } 3682 osthread->sr.set_suspend_action(os::Linux::SuspendResume::SR_NONE); 3683 return true; 3684 } 3685 else { 3686 osthread->sr.set_suspend_action(os::Linux::SuspendResume::SR_NONE); 3687 return false; 3688 } 3689} 3690 3691static void do_resume(OSThread* osthread) { 3692 assert(osthread->sr.is_suspended(), "thread should be suspended"); 3693 osthread->sr.set_suspend_action(os::Linux::SuspendResume::SR_CONTINUE); 3694 3695 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3696 assert_status(status == 0, status, "pthread_kill"); 3697 // check status and wait unit notified of resumption 3698 if (status == 0) { 3699 for (int i = 0; osthread->sr.is_suspended(); i++) { 3700 os::yield_all(i); 3701 } 3702 } 3703 osthread->sr.set_suspend_action(os::Linux::SuspendResume::SR_NONE); 3704} 3705 3706//////////////////////////////////////////////////////////////////////////////// 3707// interrupt support 3708 3709void os::interrupt(Thread* thread) { 3710 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3711 "possibility of dangling Thread pointer"); 3712 3713 OSThread* osthread = thread->osthread(); 3714 3715 if (!osthread->interrupted()) { 3716 osthread->set_interrupted(true); 3717 // More than one thread can get here with the same value of osthread, 3718 // resulting in multiple notifications. We do, however, want the store 3719 // to interrupted() to be visible to other threads before we execute unpark(). 3720 OrderAccess::fence(); 3721 ParkEvent * const slp = thread->_SleepEvent ; 3722 if (slp != NULL) slp->unpark() ; 3723 } 3724 3725 // For JSR166. Unpark even if interrupt status already was set 3726 if (thread->is_Java_thread()) 3727 ((JavaThread*)thread)->parker()->unpark(); 3728 3729 ParkEvent * ev = thread->_ParkEvent ; 3730 if (ev != NULL) ev->unpark() ; 3731 3732} 3733 3734bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 3735 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3736 "possibility of dangling Thread pointer"); 3737 3738 OSThread* osthread = thread->osthread(); 3739 3740 bool interrupted = osthread->interrupted(); 3741 3742 if (interrupted && clear_interrupted) { 3743 osthread->set_interrupted(false); 3744 // consider thread->_SleepEvent->reset() ... optional optimization 3745 } 3746 3747 return interrupted; 3748} 3749 3750/////////////////////////////////////////////////////////////////////////////////// 3751// signal handling (except suspend/resume) 3752 3753// This routine may be used by user applications as a "hook" to catch signals. 3754// The user-defined signal handler must pass unrecognized signals to this 3755// routine, and if it returns true (non-zero), then the signal handler must 3756// return immediately. If the flag "abort_if_unrecognized" is true, then this 3757// routine will never retun false (zero), but instead will execute a VM panic 3758// routine kill the process. 3759// 3760// If this routine returns false, it is OK to call it again. This allows 3761// the user-defined signal handler to perform checks either before or after 3762// the VM performs its own checks. Naturally, the user code would be making 3763// a serious error if it tried to handle an exception (such as a null check 3764// or breakpoint) that the VM was generating for its own correct operation. 3765// 3766// This routine may recognize any of the following kinds of signals: 3767// SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 3768// It should be consulted by handlers for any of those signals. 3769// 3770// The caller of this routine must pass in the three arguments supplied 3771// to the function referred to in the "sa_sigaction" (not the "sa_handler") 3772// field of the structure passed to sigaction(). This routine assumes that 3773// the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 3774// 3775// Note that the VM will print warnings if it detects conflicting signal 3776// handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 3777// 3778extern "C" JNIEXPORT int 3779JVM_handle_linux_signal(int signo, siginfo_t* siginfo, 3780 void* ucontext, int abort_if_unrecognized); 3781 3782void signalHandler(int sig, siginfo_t* info, void* uc) { 3783 assert(info != NULL && uc != NULL, "it must be old kernel"); 3784 int orig_errno = errno; // Preserve errno value over signal handler. 3785 JVM_handle_linux_signal(sig, info, uc, true); 3786 errno = orig_errno; 3787} 3788 3789 3790// This boolean allows users to forward their own non-matching signals 3791// to JVM_handle_linux_signal, harmlessly. 3792bool os::Linux::signal_handlers_are_installed = false; 3793 3794// For signal-chaining 3795struct sigaction os::Linux::sigact[MAXSIGNUM]; 3796unsigned int os::Linux::sigs = 0; 3797bool os::Linux::libjsig_is_loaded = false; 3798typedef struct sigaction *(*get_signal_t)(int); 3799get_signal_t os::Linux::get_signal_action = NULL; 3800 3801struct sigaction* os::Linux::get_chained_signal_action(int sig) { 3802 struct sigaction *actp = NULL; 3803 3804 if (libjsig_is_loaded) { 3805 // Retrieve the old signal handler from libjsig 3806 actp = (*get_signal_action)(sig); 3807 } 3808 if (actp == NULL) { 3809 // Retrieve the preinstalled signal handler from jvm 3810 actp = get_preinstalled_handler(sig); 3811 } 3812 3813 return actp; 3814} 3815 3816static bool call_chained_handler(struct sigaction *actp, int sig, 3817 siginfo_t *siginfo, void *context) { 3818 // Call the old signal handler 3819 if (actp->sa_handler == SIG_DFL) { 3820 // It's more reasonable to let jvm treat it as an unexpected exception 3821 // instead of taking the default action. 3822 return false; 3823 } else if (actp->sa_handler != SIG_IGN) { 3824 if ((actp->sa_flags & SA_NODEFER) == 0) { 3825 // automaticlly block the signal 3826 sigaddset(&(actp->sa_mask), sig); 3827 } 3828 3829 sa_handler_t hand; 3830 sa_sigaction_t sa; 3831 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 3832 // retrieve the chained handler 3833 if (siginfo_flag_set) { 3834 sa = actp->sa_sigaction; 3835 } else { 3836 hand = actp->sa_handler; 3837 } 3838 3839 if ((actp->sa_flags & SA_RESETHAND) != 0) { 3840 actp->sa_handler = SIG_DFL; 3841 } 3842 3843 // try to honor the signal mask 3844 sigset_t oset; 3845 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 3846 3847 // call into the chained handler 3848 if (siginfo_flag_set) { 3849 (*sa)(sig, siginfo, context); 3850 } else { 3851 (*hand)(sig); 3852 } 3853 3854 // restore the signal mask 3855 pthread_sigmask(SIG_SETMASK, &oset, 0); 3856 } 3857 // Tell jvm's signal handler the signal is taken care of. 3858 return true; 3859} 3860 3861bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 3862 bool chained = false; 3863 // signal-chaining 3864 if (UseSignalChaining) { 3865 struct sigaction *actp = get_chained_signal_action(sig); 3866 if (actp != NULL) { 3867 chained = call_chained_handler(actp, sig, siginfo, context); 3868 } 3869 } 3870 return chained; 3871} 3872 3873struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 3874 if ((( (unsigned int)1 << sig ) & sigs) != 0) { 3875 return &sigact[sig]; 3876 } 3877 return NULL; 3878} 3879 3880void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 3881 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3882 sigact[sig] = oldAct; 3883 sigs |= (unsigned int)1 << sig; 3884} 3885 3886// for diagnostic 3887int os::Linux::sigflags[MAXSIGNUM]; 3888 3889int os::Linux::get_our_sigflags(int sig) { 3890 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3891 return sigflags[sig]; 3892} 3893 3894void os::Linux::set_our_sigflags(int sig, int flags) { 3895 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3896 sigflags[sig] = flags; 3897} 3898 3899void os::Linux::set_signal_handler(int sig, bool set_installed) { 3900 // Check for overwrite. 3901 struct sigaction oldAct; 3902 sigaction(sig, (struct sigaction*)NULL, &oldAct); 3903 3904 void* oldhand = oldAct.sa_sigaction 3905 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3906 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3907 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 3908 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 3909 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 3910 if (AllowUserSignalHandlers || !set_installed) { 3911 // Do not overwrite; user takes responsibility to forward to us. 3912 return; 3913 } else if (UseSignalChaining) { 3914 // save the old handler in jvm 3915 save_preinstalled_handler(sig, oldAct); 3916 // libjsig also interposes the sigaction() call below and saves the 3917 // old sigaction on it own. 3918 } else { 3919 fatal(err_msg("Encountered unexpected pre-existing sigaction handler " 3920 "%#lx for signal %d.", (long)oldhand, sig)); 3921 } 3922 } 3923 3924 struct sigaction sigAct; 3925 sigfillset(&(sigAct.sa_mask)); 3926 sigAct.sa_handler = SIG_DFL; 3927 if (!set_installed) { 3928 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3929 } else { 3930 sigAct.sa_sigaction = signalHandler; 3931 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3932 } 3933 // Save flags, which are set by ours 3934 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3935 sigflags[sig] = sigAct.sa_flags; 3936 3937 int ret = sigaction(sig, &sigAct, &oldAct); 3938 assert(ret == 0, "check"); 3939 3940 void* oldhand2 = oldAct.sa_sigaction 3941 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3942 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3943 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 3944} 3945 3946// install signal handlers for signals that HotSpot needs to 3947// handle in order to support Java-level exception handling. 3948 3949void os::Linux::install_signal_handlers() { 3950 if (!signal_handlers_are_installed) { 3951 signal_handlers_are_installed = true; 3952 3953 // signal-chaining 3954 typedef void (*signal_setting_t)(); 3955 signal_setting_t begin_signal_setting = NULL; 3956 signal_setting_t end_signal_setting = NULL; 3957 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3958 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 3959 if (begin_signal_setting != NULL) { 3960 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3961 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 3962 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 3963 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 3964 libjsig_is_loaded = true; 3965 assert(UseSignalChaining, "should enable signal-chaining"); 3966 } 3967 if (libjsig_is_loaded) { 3968 // Tell libjsig jvm is setting signal handlers 3969 (*begin_signal_setting)(); 3970 } 3971 3972 set_signal_handler(SIGSEGV, true); 3973 set_signal_handler(SIGPIPE, true); 3974 set_signal_handler(SIGBUS, true); 3975 set_signal_handler(SIGILL, true); 3976 set_signal_handler(SIGFPE, true); 3977 set_signal_handler(SIGXFSZ, true); 3978 3979 if (libjsig_is_loaded) { 3980 // Tell libjsig jvm finishes setting signal handlers 3981 (*end_signal_setting)(); 3982 } 3983 3984 // We don't activate signal checker if libjsig is in place, we trust ourselves 3985 // and if UserSignalHandler is installed all bets are off. 3986 // Log that signal checking is off only if -verbose:jni is specified. 3987 if (CheckJNICalls) { 3988 if (libjsig_is_loaded) { 3989 if (PrintJNIResolving) { 3990 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 3991 } 3992 check_signals = false; 3993 } 3994 if (AllowUserSignalHandlers) { 3995 if (PrintJNIResolving) { 3996 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 3997 } 3998 check_signals = false; 3999 } 4000 } 4001 } 4002} 4003 4004// This is the fastest way to get thread cpu time on Linux. 4005// Returns cpu time (user+sys) for any thread, not only for current. 4006// POSIX compliant clocks are implemented in the kernels 2.6.16+. 4007// It might work on 2.6.10+ with a special kernel/glibc patch. 4008// For reference, please, see IEEE Std 1003.1-2004: 4009// http://www.unix.org/single_unix_specification 4010 4011jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4012 struct timespec tp; 4013 int rc = os::Linux::clock_gettime(clockid, &tp); 4014 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4015 4016 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4017} 4018 4019///// 4020// glibc on Linux platform uses non-documented flag 4021// to indicate, that some special sort of signal 4022// trampoline is used. 4023// We will never set this flag, and we should 4024// ignore this flag in our diagnostic 4025#ifdef SIGNIFICANT_SIGNAL_MASK 4026#undef SIGNIFICANT_SIGNAL_MASK 4027#endif 4028#define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4029 4030static const char* get_signal_handler_name(address handler, 4031 char* buf, int buflen) { 4032 int offset; 4033 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4034 if (found) { 4035 // skip directory names 4036 const char *p1, *p2; 4037 p1 = buf; 4038 size_t len = strlen(os::file_separator()); 4039 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4040 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4041 } else { 4042 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4043 } 4044 return buf; 4045} 4046 4047static void print_signal_handler(outputStream* st, int sig, 4048 char* buf, size_t buflen) { 4049 struct sigaction sa; 4050 4051 sigaction(sig, NULL, &sa); 4052 4053 // See comment for SIGNIFICANT_SIGNAL_MASK define 4054 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4055 4056 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4057 4058 address handler = (sa.sa_flags & SA_SIGINFO) 4059 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4060 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4061 4062 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4063 st->print("SIG_DFL"); 4064 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4065 st->print("SIG_IGN"); 4066 } else { 4067 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4068 } 4069 4070 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask); 4071 4072 address rh = VMError::get_resetted_sighandler(sig); 4073 // May be, handler was resetted by VMError? 4074 if(rh != NULL) { 4075 handler = rh; 4076 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4077 } 4078 4079 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags); 4080 4081 // Check: is it our handler? 4082 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4083 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4084 // It is our signal handler 4085 // check for flags, reset system-used one! 4086 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4087 st->print( 4088 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4089 os::Linux::get_our_sigflags(sig)); 4090 } 4091 } 4092 st->cr(); 4093} 4094 4095 4096#define DO_SIGNAL_CHECK(sig) \ 4097 if (!sigismember(&check_signal_done, sig)) \ 4098 os::Linux::check_signal_handler(sig) 4099 4100// This method is a periodic task to check for misbehaving JNI applications 4101// under CheckJNI, we can add any periodic checks here 4102 4103void os::run_periodic_checks() { 4104 4105 if (check_signals == false) return; 4106 4107 // SEGV and BUS if overridden could potentially prevent 4108 // generation of hs*.log in the event of a crash, debugging 4109 // such a case can be very challenging, so we absolutely 4110 // check the following for a good measure: 4111 DO_SIGNAL_CHECK(SIGSEGV); 4112 DO_SIGNAL_CHECK(SIGILL); 4113 DO_SIGNAL_CHECK(SIGFPE); 4114 DO_SIGNAL_CHECK(SIGBUS); 4115 DO_SIGNAL_CHECK(SIGPIPE); 4116 DO_SIGNAL_CHECK(SIGXFSZ); 4117 4118 4119 // ReduceSignalUsage allows the user to override these handlers 4120 // see comments at the very top and jvm_solaris.h 4121 if (!ReduceSignalUsage) { 4122 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4123 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4124 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4125 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4126 } 4127 4128 DO_SIGNAL_CHECK(SR_signum); 4129 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 4130} 4131 4132typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4133 4134static os_sigaction_t os_sigaction = NULL; 4135 4136void os::Linux::check_signal_handler(int sig) { 4137 char buf[O_BUFLEN]; 4138 address jvmHandler = NULL; 4139 4140 4141 struct sigaction act; 4142 if (os_sigaction == NULL) { 4143 // only trust the default sigaction, in case it has been interposed 4144 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4145 if (os_sigaction == NULL) return; 4146 } 4147 4148 os_sigaction(sig, (struct sigaction*)NULL, &act); 4149 4150 4151 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4152 4153 address thisHandler = (act.sa_flags & SA_SIGINFO) 4154 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4155 : CAST_FROM_FN_PTR(address, act.sa_handler) ; 4156 4157 4158 switch(sig) { 4159 case SIGSEGV: 4160 case SIGBUS: 4161 case SIGFPE: 4162 case SIGPIPE: 4163 case SIGILL: 4164 case SIGXFSZ: 4165 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4166 break; 4167 4168 case SHUTDOWN1_SIGNAL: 4169 case SHUTDOWN2_SIGNAL: 4170 case SHUTDOWN3_SIGNAL: 4171 case BREAK_SIGNAL: 4172 jvmHandler = (address)user_handler(); 4173 break; 4174 4175 case INTERRUPT_SIGNAL: 4176 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 4177 break; 4178 4179 default: 4180 if (sig == SR_signum) { 4181 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4182 } else { 4183 return; 4184 } 4185 break; 4186 } 4187 4188 if (thisHandler != jvmHandler) { 4189 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4190 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4191 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4192 // No need to check this sig any longer 4193 sigaddset(&check_signal_done, sig); 4194 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4195 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4196 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 4197 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 4198 // No need to check this sig any longer 4199 sigaddset(&check_signal_done, sig); 4200 } 4201 4202 // Dump all the signal 4203 if (sigismember(&check_signal_done, sig)) { 4204 print_signal_handlers(tty, buf, O_BUFLEN); 4205 } 4206} 4207 4208extern void report_error(char* file_name, int line_no, char* title, char* format, ...); 4209 4210extern bool signal_name(int signo, char* buf, size_t len); 4211 4212const char* os::exception_name(int exception_code, char* buf, size_t size) { 4213 if (0 < exception_code && exception_code <= SIGRTMAX) { 4214 // signal 4215 if (!signal_name(exception_code, buf, size)) { 4216 jio_snprintf(buf, size, "SIG%d", exception_code); 4217 } 4218 return buf; 4219 } else { 4220 return NULL; 4221 } 4222} 4223 4224// this is called _before_ the most of global arguments have been parsed 4225void os::init(void) { 4226 char dummy; /* used to get a guess on initial stack address */ 4227// first_hrtime = gethrtime(); 4228 4229 // With LinuxThreads the JavaMain thread pid (primordial thread) 4230 // is different than the pid of the java launcher thread. 4231 // So, on Linux, the launcher thread pid is passed to the VM 4232 // via the sun.java.launcher.pid property. 4233 // Use this property instead of getpid() if it was correctly passed. 4234 // See bug 6351349. 4235 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid(); 4236 4237 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid(); 4238 4239 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4240 4241 init_random(1234567); 4242 4243 ThreadCritical::initialize(); 4244 4245 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4246 if (Linux::page_size() == -1) { 4247 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)", 4248 strerror(errno))); 4249 } 4250 init_page_sizes((size_t) Linux::page_size()); 4251 4252 Linux::initialize_system_info(); 4253 4254 // main_thread points to the aboriginal thread 4255 Linux::_main_thread = pthread_self(); 4256 4257 Linux::clock_init(); 4258 initial_time_count = os::elapsed_counter(); 4259 pthread_mutex_init(&dl_mutex, NULL); 4260 4261 // If the pagesize of the VM is greater than 8K determine the appropriate 4262 // number of initial guard pages. The user can change this with the 4263 // command line arguments, if needed. 4264 if (vm_page_size() > (int)Linux::vm_default_page_size()) { 4265 StackYellowPages = 1; 4266 StackRedPages = 1; 4267 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size(); 4268 } 4269} 4270 4271// To install functions for atexit system call 4272extern "C" { 4273 static void perfMemory_exit_helper() { 4274 perfMemory_exit(); 4275 } 4276} 4277 4278// this is called _after_ the global arguments have been parsed 4279jint os::init_2(void) 4280{ 4281 Linux::fast_thread_clock_init(); 4282 4283 // Allocate a single page and mark it as readable for safepoint polling 4284 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4285 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" ); 4286 4287 os::set_polling_page( polling_page ); 4288 4289#ifndef PRODUCT 4290 if(Verbose && PrintMiscellaneous) 4291 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page); 4292#endif 4293 4294 if (!UseMembar) { 4295 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4296 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page"); 4297 os::set_memory_serialize_page( mem_serialize_page ); 4298 4299#ifndef PRODUCT 4300 if(Verbose && PrintMiscellaneous) 4301 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page); 4302#endif 4303 } 4304 4305 os::large_page_init(); 4306 4307 // initialize suspend/resume support - must do this before signal_sets_init() 4308 if (SR_initialize() != 0) { 4309 perror("SR_initialize failed"); 4310 return JNI_ERR; 4311 } 4312 4313 Linux::signal_sets_init(); 4314 Linux::install_signal_handlers(); 4315 4316 // Check minimum allowable stack size for thread creation and to initialize 4317 // the java system classes, including StackOverflowError - depends on page 4318 // size. Add a page for compiler2 recursion in main thread. 4319 // Add in 2*BytesPerWord times page size to account for VM stack during 4320 // class initialization depending on 32 or 64 bit VM. 4321 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4322 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() + 4323 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size()); 4324 4325 size_t threadStackSizeInBytes = ThreadStackSize * K; 4326 if (threadStackSizeInBytes != 0 && 4327 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4328 tty->print_cr("\nThe stack size specified is too small, " 4329 "Specify at least %dk", 4330 os::Linux::min_stack_allowed/ K); 4331 return JNI_ERR; 4332 } 4333 4334 // Make the stack size a multiple of the page size so that 4335 // the yellow/red zones can be guarded. 4336 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4337 vm_page_size())); 4338 4339 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4340 4341 Linux::libpthread_init(); 4342 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4343 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n", 4344 Linux::glibc_version(), Linux::libpthread_version(), 4345 Linux::is_floating_stack() ? "floating stack" : "fixed stack"); 4346 } 4347 4348 if (UseNUMA) { 4349 if (!Linux::libnuma_init()) { 4350 UseNUMA = false; 4351 } else { 4352 if ((Linux::numa_max_node() < 1)) { 4353 // There's only one node(they start from 0), disable NUMA. 4354 UseNUMA = false; 4355 } 4356 } 4357 // With SHM large pages we cannot uncommit a page, so there's not way 4358 // we can make the adaptive lgrp chunk resizing work. If the user specified 4359 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and 4360 // disable adaptive resizing. 4361 if (UseNUMA && UseLargePages && UseSHM) { 4362 if (!FLAG_IS_DEFAULT(UseNUMA)) { 4363 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) { 4364 UseLargePages = false; 4365 } else { 4366 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing"); 4367 UseAdaptiveSizePolicy = false; 4368 UseAdaptiveNUMAChunkSizing = false; 4369 } 4370 } else { 4371 UseNUMA = false; 4372 } 4373 } 4374 if (!UseNUMA && ForceNUMA) { 4375 UseNUMA = true; 4376 } 4377 } 4378 4379 if (MaxFDLimit) { 4380 // set the number of file descriptors to max. print out error 4381 // if getrlimit/setrlimit fails but continue regardless. 4382 struct rlimit nbr_files; 4383 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4384 if (status != 0) { 4385 if (PrintMiscellaneous && (Verbose || WizardMode)) 4386 perror("os::init_2 getrlimit failed"); 4387 } else { 4388 nbr_files.rlim_cur = nbr_files.rlim_max; 4389 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4390 if (status != 0) { 4391 if (PrintMiscellaneous && (Verbose || WizardMode)) 4392 perror("os::init_2 setrlimit failed"); 4393 } 4394 } 4395 } 4396 4397 // Initialize lock used to serialize thread creation (see os::create_thread) 4398 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4399 4400 // at-exit methods are called in the reverse order of their registration. 4401 // atexit functions are called on return from main or as a result of a 4402 // call to exit(3C). There can be only 32 of these functions registered 4403 // and atexit() does not set errno. 4404 4405 if (PerfAllowAtExitRegistration) { 4406 // only register atexit functions if PerfAllowAtExitRegistration is set. 4407 // atexit functions can be delayed until process exit time, which 4408 // can be problematic for embedded VM situations. Embedded VMs should 4409 // call DestroyJavaVM() to assure that VM resources are released. 4410 4411 // note: perfMemory_exit_helper atexit function may be removed in 4412 // the future if the appropriate cleanup code can be added to the 4413 // VM_Exit VMOperation's doit method. 4414 if (atexit(perfMemory_exit_helper) != 0) { 4415 warning("os::init2 atexit(perfMemory_exit_helper) failed"); 4416 } 4417 } 4418 4419 // initialize thread priority policy 4420 prio_init(); 4421 4422 return JNI_OK; 4423} 4424 4425// this is called at the end of vm_initialization 4426void os::init_3(void) 4427{ 4428#ifdef JAVASE_EMBEDDED 4429 // Start the MemNotifyThread 4430 if (LowMemoryProtection) { 4431 MemNotifyThread::start(); 4432 } 4433 return; 4434#endif 4435} 4436 4437// Mark the polling page as unreadable 4438void os::make_polling_page_unreadable(void) { 4439 if( !guard_memory((char*)_polling_page, Linux::page_size()) ) 4440 fatal("Could not disable polling page"); 4441}; 4442 4443// Mark the polling page as readable 4444void os::make_polling_page_readable(void) { 4445 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4446 fatal("Could not enable polling page"); 4447 } 4448}; 4449 4450int os::active_processor_count() { 4451 // Linux doesn't yet have a (official) notion of processor sets, 4452 // so just return the number of online processors. 4453 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4454 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4455 return online_cpus; 4456} 4457 4458void os::set_native_thread_name(const char *name) { 4459 // Not yet implemented. 4460 return; 4461} 4462 4463bool os::distribute_processes(uint length, uint* distribution) { 4464 // Not yet implemented. 4465 return false; 4466} 4467 4468bool os::bind_to_processor(uint processor_id) { 4469 // Not yet implemented. 4470 return false; 4471} 4472 4473/// 4474 4475// Suspends the target using the signal mechanism and then grabs the PC before 4476// resuming the target. Used by the flat-profiler only 4477ExtendedPC os::get_thread_pc(Thread* thread) { 4478 // Make sure that it is called by the watcher for the VMThread 4479 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4480 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4481 4482 ExtendedPC epc; 4483 4484 OSThread* osthread = thread->osthread(); 4485 if (do_suspend(osthread)) { 4486 if (osthread->ucontext() != NULL) { 4487 epc = os::Linux::ucontext_get_pc(osthread->ucontext()); 4488 } else { 4489 // NULL context is unexpected, double-check this is the VMThread 4490 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4491 } 4492 do_resume(osthread); 4493 } 4494 // failure means pthread_kill failed for some reason - arguably this is 4495 // a fatal problem, but such problems are ignored elsewhere 4496 4497 return epc; 4498} 4499 4500int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime) 4501{ 4502 if (is_NPTL()) { 4503 return pthread_cond_timedwait(_cond, _mutex, _abstime); 4504 } else { 4505 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control 4506 // word back to default 64bit precision if condvar is signaled. Java 4507 // wants 53bit precision. Save and restore current value. 4508 int fpu = get_fpu_control_word(); 4509 int status = pthread_cond_timedwait(_cond, _mutex, _abstime); 4510 set_fpu_control_word(fpu); 4511 return status; 4512 } 4513} 4514 4515//////////////////////////////////////////////////////////////////////////////// 4516// debug support 4517 4518bool os::find(address addr, outputStream* st) { 4519 Dl_info dlinfo; 4520 memset(&dlinfo, 0, sizeof(dlinfo)); 4521 if (dladdr(addr, &dlinfo)) { 4522 st->print(PTR_FORMAT ": ", addr); 4523 if (dlinfo.dli_sname != NULL) { 4524 st->print("%s+%#x", dlinfo.dli_sname, 4525 addr - (intptr_t)dlinfo.dli_saddr); 4526 } else if (dlinfo.dli_fname) { 4527 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 4528 } else { 4529 st->print("<absolute address>"); 4530 } 4531 if (dlinfo.dli_fname) { 4532 st->print(" in %s", dlinfo.dli_fname); 4533 } 4534 if (dlinfo.dli_fbase) { 4535 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 4536 } 4537 st->cr(); 4538 4539 if (Verbose) { 4540 // decode some bytes around the PC 4541 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 4542 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 4543 address lowest = (address) dlinfo.dli_sname; 4544 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4545 if (begin < lowest) begin = lowest; 4546 Dl_info dlinfo2; 4547 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr 4548 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) 4549 end = (address) dlinfo2.dli_saddr; 4550 Disassembler::decode(begin, end, st); 4551 } 4552 return true; 4553 } 4554 return false; 4555} 4556 4557//////////////////////////////////////////////////////////////////////////////// 4558// misc 4559 4560// This does not do anything on Linux. This is basically a hook for being 4561// able to use structured exception handling (thread-local exception filters) 4562// on, e.g., Win32. 4563void 4564os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 4565 JavaCallArguments* args, Thread* thread) { 4566 f(value, method, args, thread); 4567} 4568 4569void os::print_statistics() { 4570} 4571 4572int os::message_box(const char* title, const char* message) { 4573 int i; 4574 fdStream err(defaultStream::error_fd()); 4575 for (i = 0; i < 78; i++) err.print_raw("="); 4576 err.cr(); 4577 err.print_raw_cr(title); 4578 for (i = 0; i < 78; i++) err.print_raw("-"); 4579 err.cr(); 4580 err.print_raw_cr(message); 4581 for (i = 0; i < 78; i++) err.print_raw("="); 4582 err.cr(); 4583 4584 char buf[16]; 4585 // Prevent process from exiting upon "read error" without consuming all CPU 4586 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4587 4588 return buf[0] == 'y' || buf[0] == 'Y'; 4589} 4590 4591int os::stat(const char *path, struct stat *sbuf) { 4592 char pathbuf[MAX_PATH]; 4593 if (strlen(path) > MAX_PATH - 1) { 4594 errno = ENAMETOOLONG; 4595 return -1; 4596 } 4597 os::native_path(strcpy(pathbuf, path)); 4598 return ::stat(pathbuf, sbuf); 4599} 4600 4601bool os::check_heap(bool force) { 4602 return true; 4603} 4604 4605int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) { 4606 return ::vsnprintf(buf, count, format, args); 4607} 4608 4609// Is a (classpath) directory empty? 4610bool os::dir_is_empty(const char* path) { 4611 DIR *dir = NULL; 4612 struct dirent *ptr; 4613 4614 dir = opendir(path); 4615 if (dir == NULL) return true; 4616 4617 /* Scan the directory */ 4618 bool result = true; 4619 char buf[sizeof(struct dirent) + MAX_PATH]; 4620 while (result && (ptr = ::readdir(dir)) != NULL) { 4621 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 4622 result = false; 4623 } 4624 } 4625 closedir(dir); 4626 return result; 4627} 4628 4629// This code originates from JDK's sysOpen and open64_w 4630// from src/solaris/hpi/src/system_md.c 4631 4632#ifndef O_DELETE 4633#define O_DELETE 0x10000 4634#endif 4635 4636// Open a file. Unlink the file immediately after open returns 4637// if the specified oflag has the O_DELETE flag set. 4638// O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c 4639 4640int os::open(const char *path, int oflag, int mode) { 4641 4642 if (strlen(path) > MAX_PATH - 1) { 4643 errno = ENAMETOOLONG; 4644 return -1; 4645 } 4646 int fd; 4647 int o_delete = (oflag & O_DELETE); 4648 oflag = oflag & ~O_DELETE; 4649 4650 fd = ::open64(path, oflag, mode); 4651 if (fd == -1) return -1; 4652 4653 //If the open succeeded, the file might still be a directory 4654 { 4655 struct stat64 buf64; 4656 int ret = ::fstat64(fd, &buf64); 4657 int st_mode = buf64.st_mode; 4658 4659 if (ret != -1) { 4660 if ((st_mode & S_IFMT) == S_IFDIR) { 4661 errno = EISDIR; 4662 ::close(fd); 4663 return -1; 4664 } 4665 } else { 4666 ::close(fd); 4667 return -1; 4668 } 4669 } 4670 4671 /* 4672 * All file descriptors that are opened in the JVM and not 4673 * specifically destined for a subprocess should have the 4674 * close-on-exec flag set. If we don't set it, then careless 3rd 4675 * party native code might fork and exec without closing all 4676 * appropriate file descriptors (e.g. as we do in closeDescriptors in 4677 * UNIXProcess.c), and this in turn might: 4678 * 4679 * - cause end-of-file to fail to be detected on some file 4680 * descriptors, resulting in mysterious hangs, or 4681 * 4682 * - might cause an fopen in the subprocess to fail on a system 4683 * suffering from bug 1085341. 4684 * 4685 * (Yes, the default setting of the close-on-exec flag is a Unix 4686 * design flaw) 4687 * 4688 * See: 4689 * 1085341: 32-bit stdio routines should support file descriptors >255 4690 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed 4691 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 4692 */ 4693#ifdef FD_CLOEXEC 4694 { 4695 int flags = ::fcntl(fd, F_GETFD); 4696 if (flags != -1) 4697 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 4698 } 4699#endif 4700 4701 if (o_delete != 0) { 4702 ::unlink(path); 4703 } 4704 return fd; 4705} 4706 4707 4708// create binary file, rewriting existing file if required 4709int os::create_binary_file(const char* path, bool rewrite_existing) { 4710 int oflags = O_WRONLY | O_CREAT; 4711 if (!rewrite_existing) { 4712 oflags |= O_EXCL; 4713 } 4714 return ::open64(path, oflags, S_IREAD | S_IWRITE); 4715} 4716 4717// return current position of file pointer 4718jlong os::current_file_offset(int fd) { 4719 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 4720} 4721 4722// move file pointer to the specified offset 4723jlong os::seek_to_file_offset(int fd, jlong offset) { 4724 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 4725} 4726 4727// This code originates from JDK's sysAvailable 4728// from src/solaris/hpi/src/native_threads/src/sys_api_td.c 4729 4730int os::available(int fd, jlong *bytes) { 4731 jlong cur, end; 4732 int mode; 4733 struct stat64 buf64; 4734 4735 if (::fstat64(fd, &buf64) >= 0) { 4736 mode = buf64.st_mode; 4737 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 4738 /* 4739 * XXX: is the following call interruptible? If so, this might 4740 * need to go through the INTERRUPT_IO() wrapper as for other 4741 * blocking, interruptible calls in this file. 4742 */ 4743 int n; 4744 if (::ioctl(fd, FIONREAD, &n) >= 0) { 4745 *bytes = n; 4746 return 1; 4747 } 4748 } 4749 } 4750 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 4751 return 0; 4752 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 4753 return 0; 4754 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 4755 return 0; 4756 } 4757 *bytes = end - cur; 4758 return 1; 4759} 4760 4761int os::socket_available(int fd, jint *pbytes) { 4762 // Linux doc says EINTR not returned, unlike Solaris 4763 int ret = ::ioctl(fd, FIONREAD, pbytes); 4764 4765 //%% note ioctl can return 0 when successful, JVM_SocketAvailable 4766 // is expected to return 0 on failure and 1 on success to the jdk. 4767 return (ret < 0) ? 0 : 1; 4768} 4769 4770// Map a block of memory. 4771char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 4772 char *addr, size_t bytes, bool read_only, 4773 bool allow_exec) { 4774 int prot; 4775 int flags = MAP_PRIVATE; 4776 4777 if (read_only) { 4778 prot = PROT_READ; 4779 } else { 4780 prot = PROT_READ | PROT_WRITE; 4781 } 4782 4783 if (allow_exec) { 4784 prot |= PROT_EXEC; 4785 } 4786 4787 if (addr != NULL) { 4788 flags |= MAP_FIXED; 4789 } 4790 4791 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 4792 fd, file_offset); 4793 if (mapped_address == MAP_FAILED) { 4794 return NULL; 4795 } 4796 return mapped_address; 4797} 4798 4799 4800// Remap a block of memory. 4801char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 4802 char *addr, size_t bytes, bool read_only, 4803 bool allow_exec) { 4804 // same as map_memory() on this OS 4805 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 4806 allow_exec); 4807} 4808 4809 4810// Unmap a block of memory. 4811bool os::pd_unmap_memory(char* addr, size_t bytes) { 4812 return munmap(addr, bytes) == 0; 4813} 4814 4815static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 4816 4817static clockid_t thread_cpu_clockid(Thread* thread) { 4818 pthread_t tid = thread->osthread()->pthread_id(); 4819 clockid_t clockid; 4820 4821 // Get thread clockid 4822 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 4823 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 4824 return clockid; 4825} 4826 4827// current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 4828// are used by JVM M&M and JVMTI to get user+sys or user CPU time 4829// of a thread. 4830// 4831// current_thread_cpu_time() and thread_cpu_time(Thread*) returns 4832// the fast estimate available on the platform. 4833 4834jlong os::current_thread_cpu_time() { 4835 if (os::Linux::supports_fast_thread_cpu_time()) { 4836 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4837 } else { 4838 // return user + sys since the cost is the same 4839 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 4840 } 4841} 4842 4843jlong os::thread_cpu_time(Thread* thread) { 4844 // consistent with what current_thread_cpu_time() returns 4845 if (os::Linux::supports_fast_thread_cpu_time()) { 4846 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4847 } else { 4848 return slow_thread_cpu_time(thread, true /* user + sys */); 4849 } 4850} 4851 4852jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 4853 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4854 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4855 } else { 4856 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 4857 } 4858} 4859 4860jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4861 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4862 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4863 } else { 4864 return slow_thread_cpu_time(thread, user_sys_cpu_time); 4865 } 4866} 4867 4868// 4869// -1 on error. 4870// 4871 4872static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4873 static bool proc_task_unchecked = true; 4874 static const char *proc_stat_path = "/proc/%d/stat"; 4875 pid_t tid = thread->osthread()->thread_id(); 4876 char *s; 4877 char stat[2048]; 4878 int statlen; 4879 char proc_name[64]; 4880 int count; 4881 long sys_time, user_time; 4882 char cdummy; 4883 int idummy; 4884 long ldummy; 4885 FILE *fp; 4886 4887 // The /proc/<tid>/stat aggregates per-process usage on 4888 // new Linux kernels 2.6+ where NPTL is supported. 4889 // The /proc/self/task/<tid>/stat still has the per-thread usage. 4890 // See bug 6328462. 4891 // There possibly can be cases where there is no directory 4892 // /proc/self/task, so we check its availability. 4893 if (proc_task_unchecked && os::Linux::is_NPTL()) { 4894 // This is executed only once 4895 proc_task_unchecked = false; 4896 fp = fopen("/proc/self/task", "r"); 4897 if (fp != NULL) { 4898 proc_stat_path = "/proc/self/task/%d/stat"; 4899 fclose(fp); 4900 } 4901 } 4902 4903 sprintf(proc_name, proc_stat_path, tid); 4904 fp = fopen(proc_name, "r"); 4905 if ( fp == NULL ) return -1; 4906 statlen = fread(stat, 1, 2047, fp); 4907 stat[statlen] = '\0'; 4908 fclose(fp); 4909 4910 // Skip pid and the command string. Note that we could be dealing with 4911 // weird command names, e.g. user could decide to rename java launcher 4912 // to "java 1.4.2 :)", then the stat file would look like 4913 // 1234 (java 1.4.2 :)) R ... ... 4914 // We don't really need to know the command string, just find the last 4915 // occurrence of ")" and then start parsing from there. See bug 4726580. 4916 s = strrchr(stat, ')'); 4917 if (s == NULL ) return -1; 4918 4919 // Skip blank chars 4920 do s++; while (isspace(*s)); 4921 4922 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 4923 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 4924 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 4925 &user_time, &sys_time); 4926 if ( count != 13 ) return -1; 4927 if (user_sys_cpu_time) { 4928 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4929 } else { 4930 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4931 } 4932} 4933 4934void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4935 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4936 info_ptr->may_skip_backward = false; // elapsed time not wall time 4937 info_ptr->may_skip_forward = false; // elapsed time not wall time 4938 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4939} 4940 4941void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4942 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4943 info_ptr->may_skip_backward = false; // elapsed time not wall time 4944 info_ptr->may_skip_forward = false; // elapsed time not wall time 4945 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4946} 4947 4948bool os::is_thread_cpu_time_supported() { 4949 return true; 4950} 4951 4952// System loadavg support. Returns -1 if load average cannot be obtained. 4953// Linux doesn't yet have a (official) notion of processor sets, 4954// so just return the system wide load average. 4955int os::loadavg(double loadavg[], int nelem) { 4956 return ::getloadavg(loadavg, nelem); 4957} 4958 4959void os::pause() { 4960 char filename[MAX_PATH]; 4961 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 4962 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 4963 } else { 4964 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 4965 } 4966 4967 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 4968 if (fd != -1) { 4969 struct stat buf; 4970 ::close(fd); 4971 while (::stat(filename, &buf) == 0) { 4972 (void)::poll(NULL, 0, 100); 4973 } 4974 } else { 4975 jio_fprintf(stderr, 4976 "Could not open pause file '%s', continuing immediately.\n", filename); 4977 } 4978} 4979 4980 4981// Refer to the comments in os_solaris.cpp park-unpark. 4982// 4983// Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 4984// hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 4985// For specifics regarding the bug see GLIBC BUGID 261237 : 4986// http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 4987// Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 4988// will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 4989// is used. (The simple C test-case provided in the GLIBC bug report manifests the 4990// hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 4991// and monitorenter when we're using 1-0 locking. All those operations may result in 4992// calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 4993// of libpthread avoids the problem, but isn't practical. 4994// 4995// Possible remedies: 4996// 4997// 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 4998// This is palliative and probabilistic, however. If the thread is preempted 4999// between the call to compute_abstime() and pthread_cond_timedwait(), more 5000// than the minimum period may have passed, and the abstime may be stale (in the 5001// past) resultin in a hang. Using this technique reduces the odds of a hang 5002// but the JVM is still vulnerable, particularly on heavily loaded systems. 5003// 5004// 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 5005// of the usual flag-condvar-mutex idiom. The write side of the pipe is set 5006// NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 5007// reduces to poll()+read(). This works well, but consumes 2 FDs per extant 5008// thread. 5009// 5010// 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 5011// that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 5012// a timeout request to the chron thread and then blocking via pthread_cond_wait(). 5013// This also works well. In fact it avoids kernel-level scalability impediments 5014// on certain platforms that don't handle lots of active pthread_cond_timedwait() 5015// timers in a graceful fashion. 5016// 5017// 4. When the abstime value is in the past it appears that control returns 5018// correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 5019// Subsequent timedwait/wait calls may hang indefinitely. Given that, we 5020// can avoid the problem by reinitializing the condvar -- by cond_destroy() 5021// followed by cond_init() -- after all calls to pthread_cond_timedwait(). 5022// It may be possible to avoid reinitialization by checking the return 5023// value from pthread_cond_timedwait(). In addition to reinitializing the 5024// condvar we must establish the invariant that cond_signal() is only called 5025// within critical sections protected by the adjunct mutex. This prevents 5026// cond_signal() from "seeing" a condvar that's in the midst of being 5027// reinitialized or that is corrupt. Sadly, this invariant obviates the 5028// desirable signal-after-unlock optimization that avoids futile context switching. 5029// 5030// I'm also concerned that some versions of NTPL might allocate an auxilliary 5031// structure when a condvar is used or initialized. cond_destroy() would 5032// release the helper structure. Our reinitialize-after-timedwait fix 5033// put excessive stress on malloc/free and locks protecting the c-heap. 5034// 5035// We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 5036// It may be possible to refine (4) by checking the kernel and NTPL verisons 5037// and only enabling the work-around for vulnerable environments. 5038 5039// utility to compute the abstime argument to timedwait: 5040// millis is the relative timeout time 5041// abstime will be the absolute timeout time 5042// TODO: replace compute_abstime() with unpackTime() 5043 5044static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5045 if (millis < 0) millis = 0; 5046 struct timeval now; 5047 int status = gettimeofday(&now, NULL); 5048 assert(status == 0, "gettimeofday"); 5049 jlong seconds = millis / 1000; 5050 millis %= 1000; 5051 if (seconds > 50000000) { // see man cond_timedwait(3T) 5052 seconds = 50000000; 5053 } 5054 abstime->tv_sec = now.tv_sec + seconds; 5055 long usec = now.tv_usec + millis * 1000; 5056 if (usec >= 1000000) { 5057 abstime->tv_sec += 1; 5058 usec -= 1000000; 5059 } 5060 abstime->tv_nsec = usec * 1000; 5061 return abstime; 5062} 5063 5064 5065// Test-and-clear _Event, always leaves _Event set to 0, returns immediately. 5066// Conceptually TryPark() should be equivalent to park(0). 5067 5068int os::PlatformEvent::TryPark() { 5069 for (;;) { 5070 const int v = _Event ; 5071 guarantee ((v == 0) || (v == 1), "invariant") ; 5072 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ; 5073 } 5074} 5075 5076void os::PlatformEvent::park() { // AKA "down()" 5077 // Invariant: Only the thread associated with the Event/PlatformEvent 5078 // may call park(). 5079 // TODO: assert that _Assoc != NULL or _Assoc == Self 5080 int v ; 5081 for (;;) { 5082 v = _Event ; 5083 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 5084 } 5085 guarantee (v >= 0, "invariant") ; 5086 if (v == 0) { 5087 // Do this the hard way by blocking ... 5088 int status = pthread_mutex_lock(_mutex); 5089 assert_status(status == 0, status, "mutex_lock"); 5090 guarantee (_nParked == 0, "invariant") ; 5091 ++ _nParked ; 5092 while (_Event < 0) { 5093 status = pthread_cond_wait(_cond, _mutex); 5094 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5095 // Treat this the same as if the wait was interrupted 5096 if (status == ETIME) { status = EINTR; } 5097 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5098 } 5099 -- _nParked ; 5100 5101 _Event = 0 ; 5102 status = pthread_mutex_unlock(_mutex); 5103 assert_status(status == 0, status, "mutex_unlock"); 5104 // Paranoia to ensure our locked and lock-free paths interact 5105 // correctly with each other. 5106 OrderAccess::fence(); 5107 } 5108 guarantee (_Event >= 0, "invariant") ; 5109} 5110 5111int os::PlatformEvent::park(jlong millis) { 5112 guarantee (_nParked == 0, "invariant") ; 5113 5114 int v ; 5115 for (;;) { 5116 v = _Event ; 5117 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 5118 } 5119 guarantee (v >= 0, "invariant") ; 5120 if (v != 0) return OS_OK ; 5121 5122 // We do this the hard way, by blocking the thread. 5123 // Consider enforcing a minimum timeout value. 5124 struct timespec abst; 5125 compute_abstime(&abst, millis); 5126 5127 int ret = OS_TIMEOUT; 5128 int status = pthread_mutex_lock(_mutex); 5129 assert_status(status == 0, status, "mutex_lock"); 5130 guarantee (_nParked == 0, "invariant") ; 5131 ++_nParked ; 5132 5133 // Object.wait(timo) will return because of 5134 // (a) notification 5135 // (b) timeout 5136 // (c) thread.interrupt 5137 // 5138 // Thread.interrupt and object.notify{All} both call Event::set. 5139 // That is, we treat thread.interrupt as a special case of notification. 5140 // The underlying Solaris implementation, cond_timedwait, admits 5141 // spurious/premature wakeups, but the JLS/JVM spec prevents the 5142 // JVM from making those visible to Java code. As such, we must 5143 // filter out spurious wakeups. We assume all ETIME returns are valid. 5144 // 5145 // TODO: properly differentiate simultaneous notify+interrupt. 5146 // In that case, we should propagate the notify to another waiter. 5147 5148 while (_Event < 0) { 5149 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst); 5150 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5151 pthread_cond_destroy (_cond); 5152 pthread_cond_init (_cond, NULL) ; 5153 } 5154 assert_status(status == 0 || status == EINTR || 5155 status == ETIME || status == ETIMEDOUT, 5156 status, "cond_timedwait"); 5157 if (!FilterSpuriousWakeups) break ; // previous semantics 5158 if (status == ETIME || status == ETIMEDOUT) break ; 5159 // We consume and ignore EINTR and spurious wakeups. 5160 } 5161 --_nParked ; 5162 if (_Event >= 0) { 5163 ret = OS_OK; 5164 } 5165 _Event = 0 ; 5166 status = pthread_mutex_unlock(_mutex); 5167 assert_status(status == 0, status, "mutex_unlock"); 5168 assert (_nParked == 0, "invariant") ; 5169 // Paranoia to ensure our locked and lock-free paths interact 5170 // correctly with each other. 5171 OrderAccess::fence(); 5172 return ret; 5173} 5174 5175void os::PlatformEvent::unpark() { 5176 // Transitions for _Event: 5177 // 0 :=> 1 5178 // 1 :=> 1 5179 // -1 :=> either 0 or 1; must signal target thread 5180 // That is, we can safely transition _Event from -1 to either 5181 // 0 or 1. Forcing 1 is slightly more efficient for back-to-back 5182 // unpark() calls. 5183 // See also: "Semaphores in Plan 9" by Mullender & Cox 5184 // 5185 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5186 // that it will take two back-to-back park() calls for the owning 5187 // thread to block. This has the benefit of forcing a spurious return 5188 // from the first park() call after an unpark() call which will help 5189 // shake out uses of park() and unpark() without condition variables. 5190 5191 if (Atomic::xchg(1, &_Event) >= 0) return; 5192 5193 // Wait for the thread associated with the event to vacate 5194 int status = pthread_mutex_lock(_mutex); 5195 assert_status(status == 0, status, "mutex_lock"); 5196 int AnyWaiters = _nParked; 5197 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5198 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 5199 AnyWaiters = 0; 5200 pthread_cond_signal(_cond); 5201 } 5202 status = pthread_mutex_unlock(_mutex); 5203 assert_status(status == 0, status, "mutex_unlock"); 5204 if (AnyWaiters != 0) { 5205 status = pthread_cond_signal(_cond); 5206 assert_status(status == 0, status, "cond_signal"); 5207 } 5208 5209 // Note that we signal() _after dropping the lock for "immortal" Events. 5210 // This is safe and avoids a common class of futile wakeups. In rare 5211 // circumstances this can cause a thread to return prematurely from 5212 // cond_{timed}wait() but the spurious wakeup is benign and the victim will 5213 // simply re-test the condition and re-park itself. 5214} 5215 5216 5217// JSR166 5218// ------------------------------------------------------- 5219 5220/* 5221 * The solaris and linux implementations of park/unpark are fairly 5222 * conservative for now, but can be improved. They currently use a 5223 * mutex/condvar pair, plus a a count. 5224 * Park decrements count if > 0, else does a condvar wait. Unpark 5225 * sets count to 1 and signals condvar. Only one thread ever waits 5226 * on the condvar. Contention seen when trying to park implies that someone 5227 * is unparking you, so don't wait. And spurious returns are fine, so there 5228 * is no need to track notifications. 5229 */ 5230 5231#define MAX_SECS 100000000 5232/* 5233 * This code is common to linux and solaris and will be moved to a 5234 * common place in dolphin. 5235 * 5236 * The passed in time value is either a relative time in nanoseconds 5237 * or an absolute time in milliseconds. Either way it has to be unpacked 5238 * into suitable seconds and nanoseconds components and stored in the 5239 * given timespec structure. 5240 * Given time is a 64-bit value and the time_t used in the timespec is only 5241 * a signed-32-bit value (except on 64-bit Linux) we have to watch for 5242 * overflow if times way in the future are given. Further on Solaris versions 5243 * prior to 10 there is a restriction (see cond_timedwait) that the specified 5244 * number of seconds, in abstime, is less than current_time + 100,000,000. 5245 * As it will be 28 years before "now + 100000000" will overflow we can 5246 * ignore overflow and just impose a hard-limit on seconds using the value 5247 * of "now + 100,000,000". This places a limit on the timeout of about 3.17 5248 * years from "now". 5249 */ 5250 5251static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5252 assert (time > 0, "convertTime"); 5253 5254 struct timeval now; 5255 int status = gettimeofday(&now, NULL); 5256 assert(status == 0, "gettimeofday"); 5257 5258 time_t max_secs = now.tv_sec + MAX_SECS; 5259 5260 if (isAbsolute) { 5261 jlong secs = time / 1000; 5262 if (secs > max_secs) { 5263 absTime->tv_sec = max_secs; 5264 } 5265 else { 5266 absTime->tv_sec = secs; 5267 } 5268 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5269 } 5270 else { 5271 jlong secs = time / NANOSECS_PER_SEC; 5272 if (secs >= MAX_SECS) { 5273 absTime->tv_sec = max_secs; 5274 absTime->tv_nsec = 0; 5275 } 5276 else { 5277 absTime->tv_sec = now.tv_sec + secs; 5278 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5279 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5280 absTime->tv_nsec -= NANOSECS_PER_SEC; 5281 ++absTime->tv_sec; // note: this must be <= max_secs 5282 } 5283 } 5284 } 5285 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5286 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5287 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5288 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5289} 5290 5291void Parker::park(bool isAbsolute, jlong time) { 5292 // Ideally we'd do something useful while spinning, such 5293 // as calling unpackTime(). 5294 5295 // Optional fast-path check: 5296 // Return immediately if a permit is available. 5297 // We depend on Atomic::xchg() having full barrier semantics 5298 // since we are doing a lock-free update to _counter. 5299 if (Atomic::xchg(0, &_counter) > 0) return; 5300 5301 Thread* thread = Thread::current(); 5302 assert(thread->is_Java_thread(), "Must be JavaThread"); 5303 JavaThread *jt = (JavaThread *)thread; 5304 5305 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5306 // Check interrupt before trying to wait 5307 if (Thread::is_interrupted(thread, false)) { 5308 return; 5309 } 5310 5311 // Next, demultiplex/decode time arguments 5312 timespec absTime; 5313 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all 5314 return; 5315 } 5316 if (time > 0) { 5317 unpackTime(&absTime, isAbsolute, time); 5318 } 5319 5320 5321 // Enter safepoint region 5322 // Beware of deadlocks such as 6317397. 5323 // The per-thread Parker:: mutex is a classic leaf-lock. 5324 // In particular a thread must never block on the Threads_lock while 5325 // holding the Parker:: mutex. If safepoints are pending both the 5326 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5327 ThreadBlockInVM tbivm(jt); 5328 5329 // Don't wait if cannot get lock since interference arises from 5330 // unblocking. Also. check interrupt before trying wait 5331 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5332 return; 5333 } 5334 5335 int status ; 5336 if (_counter > 0) { // no wait needed 5337 _counter = 0; 5338 status = pthread_mutex_unlock(_mutex); 5339 assert (status == 0, "invariant") ; 5340 // Paranoia to ensure our locked and lock-free paths interact 5341 // correctly with each other and Java-level accesses. 5342 OrderAccess::fence(); 5343 return; 5344 } 5345 5346#ifdef ASSERT 5347 // Don't catch signals while blocked; let the running threads have the signals. 5348 // (This allows a debugger to break into the running thread.) 5349 sigset_t oldsigs; 5350 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5351 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5352#endif 5353 5354 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5355 jt->set_suspend_equivalent(); 5356 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5357 5358 if (time == 0) { 5359 status = pthread_cond_wait (_cond, _mutex) ; 5360 } else { 5361 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ; 5362 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5363 pthread_cond_destroy (_cond) ; 5364 pthread_cond_init (_cond, NULL); 5365 } 5366 } 5367 assert_status(status == 0 || status == EINTR || 5368 status == ETIME || status == ETIMEDOUT, 5369 status, "cond_timedwait"); 5370 5371#ifdef ASSERT 5372 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5373#endif 5374 5375 _counter = 0 ; 5376 status = pthread_mutex_unlock(_mutex) ; 5377 assert_status(status == 0, status, "invariant") ; 5378 // Paranoia to ensure our locked and lock-free paths interact 5379 // correctly with each other and Java-level accesses. 5380 OrderAccess::fence(); 5381 5382 // If externally suspended while waiting, re-suspend 5383 if (jt->handle_special_suspend_equivalent_condition()) { 5384 jt->java_suspend_self(); 5385 } 5386} 5387 5388void Parker::unpark() { 5389 int s, status ; 5390 status = pthread_mutex_lock(_mutex); 5391 assert (status == 0, "invariant") ; 5392 s = _counter; 5393 _counter = 1; 5394 if (s < 1) { 5395 if (WorkAroundNPTLTimedWaitHang) { 5396 status = pthread_cond_signal (_cond) ; 5397 assert (status == 0, "invariant") ; 5398 status = pthread_mutex_unlock(_mutex); 5399 assert (status == 0, "invariant") ; 5400 } else { 5401 status = pthread_mutex_unlock(_mutex); 5402 assert (status == 0, "invariant") ; 5403 status = pthread_cond_signal (_cond) ; 5404 assert (status == 0, "invariant") ; 5405 } 5406 } else { 5407 pthread_mutex_unlock(_mutex); 5408 assert (status == 0, "invariant") ; 5409 } 5410} 5411 5412 5413extern char** environ; 5414 5415#ifndef __NR_fork 5416#define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) 5417#endif 5418 5419#ifndef __NR_execve 5420#define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) 5421#endif 5422 5423// Run the specified command in a separate process. Return its exit value, 5424// or -1 on failure (e.g. can't fork a new process). 5425// Unlike system(), this function can be called from signal handler. It 5426// doesn't block SIGINT et al. 5427int os::fork_and_exec(char* cmd) { 5428 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5429 5430 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run 5431 // pthread_atfork handlers and reset pthread library. All we need is a 5432 // separate process to execve. Make a direct syscall to fork process. 5433 // On IA64 there's no fork syscall, we have to use fork() and hope for 5434 // the best... 5435 pid_t pid = NOT_IA64(syscall(__NR_fork);) 5436 IA64_ONLY(fork();) 5437 5438 if (pid < 0) { 5439 // fork failed 5440 return -1; 5441 5442 } else if (pid == 0) { 5443 // child process 5444 5445 // execve() in LinuxThreads will call pthread_kill_other_threads_np() 5446 // first to kill every thread on the thread list. Because this list is 5447 // not reset by fork() (see notes above), execve() will instead kill 5448 // every thread in the parent process. We know this is the only thread 5449 // in the new process, so make a system call directly. 5450 // IA64 should use normal execve() from glibc to match the glibc fork() 5451 // above. 5452 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);) 5453 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);) 5454 5455 // execve failed 5456 _exit(-1); 5457 5458 } else { 5459 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5460 // care about the actual exit code, for now. 5461 5462 int status; 5463 5464 // Wait for the child process to exit. This returns immediately if 5465 // the child has already exited. */ 5466 while (waitpid(pid, &status, 0) < 0) { 5467 switch (errno) { 5468 case ECHILD: return 0; 5469 case EINTR: break; 5470 default: return -1; 5471 } 5472 } 5473 5474 if (WIFEXITED(status)) { 5475 // The child exited normally; get its exit code. 5476 return WEXITSTATUS(status); 5477 } else if (WIFSIGNALED(status)) { 5478 // The child exited because of a signal 5479 // The best value to return is 0x80 + signal number, 5480 // because that is what all Unix shells do, and because 5481 // it allows callers to distinguish between process exit and 5482 // process death by signal. 5483 return 0x80 + WTERMSIG(status); 5484 } else { 5485 // Unknown exit code; pass it through 5486 return status; 5487 } 5488 } 5489} 5490 5491// is_headless_jre() 5492// 5493// Test for the existence of xawt/libmawt.so or libawt_xawt.so 5494// in order to report if we are running in a headless jre 5495// 5496// Since JDK8 xawt/libmawt.so was moved into the same directory 5497// as libawt.so, and renamed libawt_xawt.so 5498// 5499bool os::is_headless_jre() { 5500 struct stat statbuf; 5501 char buf[MAXPATHLEN]; 5502 char libmawtpath[MAXPATHLEN]; 5503 const char *xawtstr = "/xawt/libmawt.so"; 5504 const char *new_xawtstr = "/libawt_xawt.so"; 5505 char *p; 5506 5507 // Get path to libjvm.so 5508 os::jvm_path(buf, sizeof(buf)); 5509 5510 // Get rid of libjvm.so 5511 p = strrchr(buf, '/'); 5512 if (p == NULL) return false; 5513 else *p = '\0'; 5514 5515 // Get rid of client or server 5516 p = strrchr(buf, '/'); 5517 if (p == NULL) return false; 5518 else *p = '\0'; 5519 5520 // check xawt/libmawt.so 5521 strcpy(libmawtpath, buf); 5522 strcat(libmawtpath, xawtstr); 5523 if (::stat(libmawtpath, &statbuf) == 0) return false; 5524 5525 // check libawt_xawt.so 5526 strcpy(libmawtpath, buf); 5527 strcat(libmawtpath, new_xawtstr); 5528 if (::stat(libmawtpath, &statbuf) == 0) return false; 5529 5530 return true; 5531} 5532 5533// Get the default path to the core file 5534// Returns the length of the string 5535int os::get_core_path(char* buffer, size_t bufferSize) { 5536 const char* p = get_current_directory(buffer, bufferSize); 5537 5538 if (p == NULL) { 5539 assert(p != NULL, "failed to get current directory"); 5540 return 0; 5541 } 5542 5543 return strlen(buffer); 5544} 5545 5546#ifdef JAVASE_EMBEDDED 5547// 5548// A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory. 5549// 5550MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL; 5551 5552// ctor 5553// 5554MemNotifyThread::MemNotifyThread(int fd): Thread() { 5555 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread"); 5556 _fd = fd; 5557 5558 if (os::create_thread(this, os::os_thread)) { 5559 _memnotify_thread = this; 5560 os::set_priority(this, NearMaxPriority); 5561 os::start_thread(this); 5562 } 5563} 5564 5565// Where all the work gets done 5566// 5567void MemNotifyThread::run() { 5568 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread"); 5569 5570 // Set up the select arguments 5571 fd_set rfds; 5572 if (_fd != -1) { 5573 FD_ZERO(&rfds); 5574 FD_SET(_fd, &rfds); 5575 } 5576 5577 // Now wait for the mem_notify device to wake up 5578 while (1) { 5579 // Wait for the mem_notify device to signal us.. 5580 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL); 5581 if (rc == -1) { 5582 perror("select!\n"); 5583 break; 5584 } else if (rc) { 5585 //ssize_t free_before = os::available_memory(); 5586 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024); 5587 5588 // The kernel is telling us there is not much memory left... 5589 // try to do something about that 5590 5591 // If we are not already in a GC, try one. 5592 if (!Universe::heap()->is_gc_active()) { 5593 Universe::heap()->collect(GCCause::_allocation_failure); 5594 5595 //ssize_t free_after = os::available_memory(); 5596 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024); 5597 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024); 5598 } 5599 // We might want to do something like the following if we find the GC's are not helping... 5600 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true); 5601 } 5602 } 5603} 5604 5605// 5606// See if the /dev/mem_notify device exists, and if so, start a thread to monitor it. 5607// 5608void MemNotifyThread::start() { 5609 int fd; 5610 fd = open ("/dev/mem_notify", O_RDONLY, 0); 5611 if (fd < 0) { 5612 return; 5613 } 5614 5615 if (memnotify_thread() == NULL) { 5616 new MemNotifyThread(fd); 5617 } 5618} 5619#endif // JAVASE_EMBEDDED 5620