1 /* 2 * Copyright 1999-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25 // do not include precompiled header file 26 # include "incls/_os_linux.cpp.incl" 27 28 // put OS-includes here 29 # include <sys/types.h> 30 # include <sys/mman.h> 31 # include <pthread.h> 32 # include <signal.h> 33 # include <errno.h> 34 # include <dlfcn.h> 35 # include <stdio.h> 36 # include <unistd.h> 37 # include <sys/resource.h> 38 # include <pthread.h> 39 # include <sys/stat.h> 40 # include <sys/time.h> 41 # include <sys/times.h> 42 # include <sys/utsname.h> 43 # include <sys/socket.h> 44 # include <sys/wait.h> 45 # include <pwd.h> 46 # include <poll.h> 47 # include <semaphore.h> 48 # include <fcntl.h> 49 # include <string.h> 50 # include <syscall.h> 51 # include <sys/sysinfo.h> 52 # include <gnu/libc-version.h> 53 # include <sys/ipc.h> 54 # include <sys/shm.h> 55 # include <link.h> 56 57 #include <sstream> 58 #include <iostream> 59 #include <fstream> 60 61 #define MAX_PATH (2 * K) 62 63 // for timer info max values which include all bits 64 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 65 #define SEC_IN_NANOSECS 1000000000LL 66 67 //////////////////////////////////////////////////////////////////////////////// 68 // global variables 69 julong os::Linux::_physical_memory = 0; 70 71 address os::Linux::_initial_thread_stack_bottom = NULL; 72 uintptr_t os::Linux::_initial_thread_stack_size = 0; 73 74 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 75 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 76 Mutex* os::Linux::_createThread_lock = NULL; 77 pthread_t os::Linux::_main_thread; 78 int os::Linux::_page_size = -1; 79 bool os::Linux::_is_floating_stack = false; 80 bool os::Linux::_is_NPTL = false; 81 bool os::Linux::_supports_fast_thread_cpu_time = false; 82 const char * os::Linux::_glibc_version = NULL; 83 const char * os::Linux::_libpthread_version = NULL; 84 85 static jlong initial_time_count=0; 86 87 static int clock_tics_per_sec = 100; 88 89 // For diagnostics to print a message once. see run_periodic_checks 90 static sigset_t check_signal_done; 91 static bool check_signals = true;; 92 93 static pid_t _initial_pid = 0; 94 95 /* Signal number used to suspend/resume a thread */ 96 97 /* do not use any signal number less than SIGSEGV, see 4355769 */ 98 static int SR_signum = SIGUSR2; 99 sigset_t SR_sigset; 100 101 /* Used to protect dlsym() calls */ 102 static pthread_mutex_t dl_mutex; 103 104 //////////////////////////////////////////////////////////////////////////////// 105 // utility functions 106 107 static int SR_initialize(); 108 static int SR_finalize(); 109 110 julong os::available_memory() { 111 return Linux::available_memory(); 112 } 113 114 julong os::Linux::available_memory() { 115 // values in struct sysinfo are "unsigned long" 116 struct sysinfo si; 117 sysinfo(&si); 118 119 return (julong)si.freeram * si.mem_unit; 120 } 121 122 julong os::physical_memory() { 123 return Linux::physical_memory(); 124 } 125 126 julong os::allocatable_physical_memory(julong size) { 127 #ifdef _LP64 128 return size; 129 #else 130 julong result = MIN2(size, (julong)3800*M); 131 if (!is_allocatable(result)) { 132 // See comments under solaris for alignment considerations 133 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size(); 134 result = MIN2(size, reasonable_size); 135 } 136 return result; 137 #endif // _LP64 138 } 139 140 //////////////////////////////////////////////////////////////////////////////// 141 // environment support 142 143 bool os::getenv(const char* name, char* buf, int len) { 144 const char* val = ::getenv(name); 145 if (val != NULL && strlen(val) < (size_t)len) { 146 strcpy(buf, val); 147 return true; 148 } 149 if (len > 0) buf[0] = 0; // return a null string 150 return false; 151 } 152 153 154 // Return true if user is running as root. 155 156 bool os::have_special_privileges() { 157 static bool init = false; 158 static bool privileges = false; 159 if (!init) { 160 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 161 init = true; 162 } 163 return privileges; 164 } 165 166 167 #ifndef SYS_gettid 168 // i386: 224, ia64: 1105, amd64: 186, sparc 143 169 #ifdef __ia64__ 170 #define SYS_gettid 1105 171 #elif __i386__ 172 #define SYS_gettid 224 173 #elif __amd64__ 174 #define SYS_gettid 186 175 #elif __sparc__ 176 #define SYS_gettid 143 177 #else 178 #error define gettid for the arch 179 #endif 180 #endif 181 182 // Cpu architecture string 183 #if defined(ZERO) 184 static char cpu_arch[] = ZERO_LIBARCH; 185 #elif defined(IA64) 186 static char cpu_arch[] = "ia64"; 187 #elif defined(IA32) 188 static char cpu_arch[] = "i386"; 189 #elif defined(AMD64) 190 static char cpu_arch[] = "amd64"; 191 #elif defined(SPARC) 192 # ifdef _LP64 193 static char cpu_arch[] = "sparcv9"; 194 # else 195 static char cpu_arch[] = "sparc"; 196 # endif 197 #else 198 #error Add appropriate cpu_arch setting 199 #endif 200 201 202 // pid_t gettid() 203 // 204 // Returns the kernel thread id of the currently running thread. Kernel 205 // thread id is used to access /proc. 206 // 207 // (Note that getpid() on LinuxThreads returns kernel thread id too; but 208 // on NPTL, it returns the same pid for all threads, as required by POSIX.) 209 // 210 pid_t os::Linux::gettid() { 211 int rslt = syscall(SYS_gettid); 212 if (rslt == -1) { 213 // old kernel, no NPTL support 214 return getpid(); 215 } else { 216 return (pid_t)rslt; 217 } 218 } 219 220 // Most versions of linux have a bug where the number of processors are 221 // determined by looking at the /proc file system. In a chroot environment, 222 // the system call returns 1. This causes the VM to act as if it is 223 // a single processor and elide locking (see is_MP() call). 224 static bool unsafe_chroot_detected = false; 225 static const char *unstable_chroot_error = "/proc file system not found.\n" 226 "Java may be unstable running multithreaded in a chroot " 227 "environment on Linux when /proc filesystem is not mounted."; 228 229 void os::Linux::initialize_system_info() { 230 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 231 if (processor_count() == 1) { 232 pid_t pid = os::Linux::gettid(); 233 char fname[32]; 234 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 235 FILE *fp = fopen(fname, "r"); 236 if (fp == NULL) { 237 unsafe_chroot_detected = true; 238 } else { 239 fclose(fp); 240 } 241 } 242 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 243 assert(processor_count() > 0, "linux error"); 244 } 245 246 void os::init_system_properties_values() { 247 // char arch[12]; 248 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch)); 249 250 // The next steps are taken in the product version: 251 // 252 // Obtain the JAVA_HOME value from the location of libjvm[_g].so. 253 // This library should be located at: 254 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so. 255 // 256 // If "/jre/lib/" appears at the right place in the path, then we 257 // assume libjvm[_g].so is installed in a JDK and we use this path. 258 // 259 // Otherwise exit with message: "Could not create the Java virtual machine." 260 // 261 // The following extra steps are taken in the debugging version: 262 // 263 // If "/jre/lib/" does NOT appear at the right place in the path 264 // instead of exit check for $JAVA_HOME environment variable. 265 // 266 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 267 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so 268 // it looks like libjvm[_g].so is installed there 269 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so. 270 // 271 // Otherwise exit. 272 // 273 // Important note: if the location of libjvm.so changes this 274 // code needs to be changed accordingly. 275 276 // The next few definitions allow the code to be verbatim: 277 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n)) 278 #define getenv(n) ::getenv(n) 279 280 /* 281 * See ld(1): 282 * The linker uses the following search paths to locate required 283 * shared libraries: 284 * 1: ... 285 * ... 286 * 7: The default directories, normally /lib and /usr/lib. 287 */ 288 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 289 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 290 #else 291 #define DEFAULT_LIBPATH "/lib:/usr/lib" 292 #endif 293 294 #define EXTENSIONS_DIR "/lib/ext" 295 #define ENDORSED_DIR "/lib/endorsed" 296 #define REG_DIR "/usr/java/packages" 297 298 { 299 /* sysclasspath, java_home, dll_dir */ 300 { 301 char *home_path; 302 char *dll_path; 303 char *pslash; 304 char buf[MAXPATHLEN]; 305 os::jvm_path(buf, sizeof(buf)); 306 307 // Found the full path to libjvm.so. 308 // Now cut the path to <java_home>/jre if we can. 309 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */ 310 pslash = strrchr(buf, '/'); 311 if (pslash != NULL) 312 *pslash = '\0'; /* get rid of /{client|server|hotspot} */ 313 dll_path = malloc(strlen(buf) + 1); 314 if (dll_path == NULL) 315 return; 316 strcpy(dll_path, buf); 317 Arguments::set_dll_dir(dll_path); 318 319 if (pslash != NULL) { 320 pslash = strrchr(buf, '/'); 321 if (pslash != NULL) { 322 *pslash = '\0'; /* get rid of /<arch> */ 323 pslash = strrchr(buf, '/'); 324 if (pslash != NULL) 325 *pslash = '\0'; /* get rid of /lib */ 326 } 327 } 328 329 home_path = malloc(strlen(buf) + 1); 330 if (home_path == NULL) 331 return; 332 strcpy(home_path, buf); 333 Arguments::set_java_home(home_path); 334 335 if (!set_boot_path('/', ':')) 336 return; 337 } 338 339 /* 340 * Where to look for native libraries 341 * 342 * Note: Due to a legacy implementation, most of the library path 343 * is set in the launcher. This was to accomodate linking restrictions 344 * on legacy Linux implementations (which are no longer supported). 345 * Eventually, all the library path setting will be done here. 346 * 347 * However, to prevent the proliferation of improperly built native 348 * libraries, the new path component /usr/java/packages is added here. 349 * Eventually, all the library path setting will be done here. 350 */ 351 { 352 char *ld_library_path; 353 354 /* 355 * Construct the invariant part of ld_library_path. Note that the 356 * space for the colon and the trailing null are provided by the 357 * nulls included by the sizeof operator (so actually we allocate 358 * a byte more than necessary). 359 */ 360 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") + 361 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH)); 362 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch); 363 364 /* 365 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It 366 * should always exist (until the legacy problem cited above is 367 * addressed). 368 */ 369 char *v = getenv("LD_LIBRARY_PATH"); 370 if (v != NULL) { 371 char *t = ld_library_path; 372 /* That's +1 for the colon and +1 for the trailing '\0' */ 373 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1); 374 sprintf(ld_library_path, "%s:%s", v, t); 375 } 376 Arguments::set_library_path(ld_library_path); 377 } 378 379 /* 380 * Extensions directories. 381 * 382 * Note that the space for the colon and the trailing null are provided 383 * by the nulls included by the sizeof operator (so actually one byte more 384 * than necessary is allocated). 385 */ 386 { 387 char *buf = malloc(strlen(Arguments::get_java_home()) + 388 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR)); 389 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR, 390 Arguments::get_java_home()); 391 Arguments::set_ext_dirs(buf); 392 } 393 394 /* Endorsed standards default directory. */ 395 { 396 char * buf; 397 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR)); 398 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home()); 399 Arguments::set_endorsed_dirs(buf); 400 } 401 } 402 403 #undef malloc 404 #undef getenv 405 #undef EXTENSIONS_DIR 406 #undef ENDORSED_DIR 407 408 // Done 409 return; 410 } 411 412 //////////////////////////////////////////////////////////////////////////////// 413 // breakpoint support 414 415 void os::breakpoint() { 416 BREAKPOINT; 417 } 418 419 extern "C" void breakpoint() { 420 // use debugger to set breakpoint here 421 } 422 423 //////////////////////////////////////////////////////////////////////////////// 424 // signal support 425 426 debug_only(static bool signal_sets_initialized = false); 427 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 428 429 bool os::Linux::is_sig_ignored(int sig) { 430 struct sigaction oact; 431 sigaction(sig, (struct sigaction*)NULL, &oact); 432 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 433 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 434 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) 435 return true; 436 else 437 return false; 438 } 439 440 void os::Linux::signal_sets_init() { 441 // Should also have an assertion stating we are still single-threaded. 442 assert(!signal_sets_initialized, "Already initialized"); 443 // Fill in signals that are necessarily unblocked for all threads in 444 // the VM. Currently, we unblock the following signals: 445 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 446 // by -Xrs (=ReduceSignalUsage)); 447 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 448 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 449 // the dispositions or masks wrt these signals. 450 // Programs embedding the VM that want to use the above signals for their 451 // own purposes must, at this time, use the "-Xrs" option to prevent 452 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 453 // (See bug 4345157, and other related bugs). 454 // In reality, though, unblocking these signals is really a nop, since 455 // these signals are not blocked by default. 456 sigemptyset(&unblocked_sigs); 457 sigemptyset(&allowdebug_blocked_sigs); 458 sigaddset(&unblocked_sigs, SIGILL); 459 sigaddset(&unblocked_sigs, SIGSEGV); 460 sigaddset(&unblocked_sigs, SIGBUS); 461 sigaddset(&unblocked_sigs, SIGFPE); 462 sigaddset(&unblocked_sigs, SR_signum); 463 464 if (!ReduceSignalUsage) { 465 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 466 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 467 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 468 } 469 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 470 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 471 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 472 } 473 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 474 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 475 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 476 } 477 } 478 // Fill in signals that are blocked by all but the VM thread. 479 sigemptyset(&vm_sigs); 480 if (!ReduceSignalUsage) 481 sigaddset(&vm_sigs, BREAK_SIGNAL); 482 debug_only(signal_sets_initialized = true); 483 484 } 485 486 // These are signals that are unblocked while a thread is running Java. 487 // (For some reason, they get blocked by default.) 488 sigset_t* os::Linux::unblocked_signals() { 489 assert(signal_sets_initialized, "Not initialized"); 490 return &unblocked_sigs; 491 } 492 493 // These are the signals that are blocked while a (non-VM) thread is 494 // running Java. Only the VM thread handles these signals. 495 sigset_t* os::Linux::vm_signals() { 496 assert(signal_sets_initialized, "Not initialized"); 497 return &vm_sigs; 498 } 499 500 // These are signals that are blocked during cond_wait to allow debugger in 501 sigset_t* os::Linux::allowdebug_blocked_signals() { 502 assert(signal_sets_initialized, "Not initialized"); 503 return &allowdebug_blocked_sigs; 504 } 505 506 void os::Linux::hotspot_sigmask(Thread* thread) { 507 508 //Save caller's signal mask before setting VM signal mask 509 sigset_t caller_sigmask; 510 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 511 512 OSThread* osthread = thread->osthread(); 513 osthread->set_caller_sigmask(caller_sigmask); 514 515 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 516 517 if (!ReduceSignalUsage) { 518 if (thread->is_VM_thread()) { 519 // Only the VM thread handles BREAK_SIGNAL ... 520 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 521 } else { 522 // ... all other threads block BREAK_SIGNAL 523 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 524 } 525 } 526 } 527 528 ////////////////////////////////////////////////////////////////////////////// 529 // detecting pthread library 530 531 void os::Linux::libpthread_init() { 532 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION 533 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a 534 // generic name for earlier versions. 535 // Define macros here so we can build HotSpot on old systems. 536 # ifndef _CS_GNU_LIBC_VERSION 537 # define _CS_GNU_LIBC_VERSION 2 538 # endif 539 # ifndef _CS_GNU_LIBPTHREAD_VERSION 540 # define _CS_GNU_LIBPTHREAD_VERSION 3 541 # endif 542 543 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 544 if (n > 0) { 545 char *str = (char *)malloc(n); 546 confstr(_CS_GNU_LIBC_VERSION, str, n); 547 os::Linux::set_glibc_version(str); 548 } else { 549 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version() 550 static char _gnu_libc_version[32]; 551 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version), 552 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release()); 553 os::Linux::set_glibc_version(_gnu_libc_version); 554 } 555 556 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 557 if (n > 0) { 558 char *str = (char *)malloc(n); 559 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 560 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells 561 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this 562 // is the case. LinuxThreads has a hard limit on max number of threads. 563 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value. 564 // On the other hand, NPTL does not have such a limit, sysconf() 565 // will return -1 and errno is not changed. Check if it is really NPTL. 566 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 && 567 strstr(str, "NPTL") && 568 sysconf(_SC_THREAD_THREADS_MAX) > 0) { 569 free(str); 570 os::Linux::set_libpthread_version("linuxthreads"); 571 } else { 572 os::Linux::set_libpthread_version(str); 573 } 574 } else { 575 // glibc before 2.3.2 only has LinuxThreads. 576 os::Linux::set_libpthread_version("linuxthreads"); 577 } 578 579 if (strstr(libpthread_version(), "NPTL")) { 580 os::Linux::set_is_NPTL(); 581 } else { 582 os::Linux::set_is_LinuxThreads(); 583 } 584 585 // LinuxThreads have two flavors: floating-stack mode, which allows variable 586 // stack size; and fixed-stack mode. NPTL is always floating-stack. 587 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) { 588 os::Linux::set_is_floating_stack(); 589 } 590 } 591 592 ///////////////////////////////////////////////////////////////////////////// 593 // thread stack 594 595 // Force Linux kernel to expand current thread stack. If "bottom" is close 596 // to the stack guard, caller should block all signals. 597 // 598 // MAP_GROWSDOWN: 599 // A special mmap() flag that is used to implement thread stacks. It tells 600 // kernel that the memory region should extend downwards when needed. This 601 // allows early versions of LinuxThreads to only mmap the first few pages 602 // when creating a new thread. Linux kernel will automatically expand thread 603 // stack as needed (on page faults). 604 // 605 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 606 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 607 // region, it's hard to tell if the fault is due to a legitimate stack 608 // access or because of reading/writing non-exist memory (e.g. buffer 609 // overrun). As a rule, if the fault happens below current stack pointer, 610 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 611 // application (see Linux kernel fault.c). 612 // 613 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 614 // stack overflow detection. 615 // 616 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 617 // not use this flag. However, the stack of initial thread is not created 618 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though 619 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack 620 // and then attach the thread to JVM. 621 // 622 // To get around the problem and allow stack banging on Linux, we need to 623 // manually expand thread stack after receiving the SIGSEGV. 624 // 625 // There are two ways to expand thread stack to address "bottom", we used 626 // both of them in JVM before 1.5: 627 // 1. adjust stack pointer first so that it is below "bottom", and then 628 // touch "bottom" 629 // 2. mmap() the page in question 630 // 631 // Now alternate signal stack is gone, it's harder to use 2. For instance, 632 // if current sp is already near the lower end of page 101, and we need to 633 // call mmap() to map page 100, it is possible that part of the mmap() frame 634 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 635 // That will destroy the mmap() frame and cause VM to crash. 636 // 637 // The following code works by adjusting sp first, then accessing the "bottom" 638 // page to force a page fault. Linux kernel will then automatically expand the 639 // stack mapping. 640 // 641 // _expand_stack_to() assumes its frame size is less than page size, which 642 // should always be true if the function is not inlined. 643 644 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 645 #define NOINLINE 646 #else 647 #define NOINLINE __attribute__ ((noinline)) 648 #endif 649 650 static void _expand_stack_to(address bottom) NOINLINE; 651 652 static void _expand_stack_to(address bottom) { 653 address sp; 654 size_t size; 655 volatile char *p; 656 657 // Adjust bottom to point to the largest address within the same page, it 658 // gives us a one-page buffer if alloca() allocates slightly more memory. 659 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 660 bottom += os::Linux::page_size() - 1; 661 662 // sp might be slightly above current stack pointer; if that's the case, we 663 // will alloca() a little more space than necessary, which is OK. Don't use 664 // os::current_stack_pointer(), as its result can be slightly below current 665 // stack pointer, causing us to not alloca enough to reach "bottom". 666 sp = (address)&sp; 667 668 if (sp > bottom) { 669 size = sp - bottom; 670 p = (volatile char *)alloca(size); 671 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 672 p[0] = '\0'; 673 } 674 } 675 676 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 677 assert(t!=NULL, "just checking"); 678 assert(t->osthread()->expanding_stack(), "expand should be set"); 679 assert(t->stack_base() != NULL, "stack_base was not initialized"); 680 681 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 682 sigset_t mask_all, old_sigset; 683 sigfillset(&mask_all); 684 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 685 _expand_stack_to(addr); 686 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 687 return true; 688 } 689 return false; 690 } 691 692 ////////////////////////////////////////////////////////////////////////////// 693 // create new thread 694 695 static address highest_vm_reserved_address(); 696 697 // check if it's safe to start a new thread 698 static bool _thread_safety_check(Thread* thread) { 699 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) { 700 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat) 701 // Heap is mmap'ed at lower end of memory space. Thread stacks are 702 // allocated (MAP_FIXED) from high address space. Every thread stack 703 // occupies a fixed size slot (usually 2Mbytes, but user can change 704 // it to other values if they rebuild LinuxThreads). 705 // 706 // Problem with MAP_FIXED is that mmap() can still succeed even part of 707 // the memory region has already been mmap'ed. That means if we have too 708 // many threads and/or very large heap, eventually thread stack will 709 // collide with heap. 710 // 711 // Here we try to prevent heap/stack collision by comparing current 712 // stack bottom with the highest address that has been mmap'ed by JVM 713 // plus a safety margin for memory maps created by native code. 714 // 715 // This feature can be disabled by setting ThreadSafetyMargin to 0 716 // 717 if (ThreadSafetyMargin > 0) { 718 address stack_bottom = os::current_stack_base() - os::current_stack_size(); 719 720 // not safe if our stack extends below the safety margin 721 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address(); 722 } else { 723 return true; 724 } 725 } else { 726 // Floating stack LinuxThreads or NPTL: 727 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When 728 // there's not enough space left, pthread_create() will fail. If we come 729 // here, that means enough space has been reserved for stack. 730 return true; 731 } 732 } 733 734 // Thread start routine for all newly created threads 735 static void *java_start(Thread *thread) { 736 // Try to randomize the cache line index of hot stack frames. 737 // This helps when threads of the same stack traces evict each other's 738 // cache lines. The threads can be either from the same JVM instance, or 739 // from different JVM instances. The benefit is especially true for 740 // processors with hyperthreading technology. 741 static int counter = 0; 742 int pid = os::current_process_id(); 743 alloca(((pid ^ counter++) & 7) * 128); 744 745 ThreadLocalStorage::set_thread(thread); 746 747 OSThread* osthread = thread->osthread(); 748 Monitor* sync = osthread->startThread_lock(); 749 750 // non floating stack LinuxThreads needs extra check, see above 751 if (!_thread_safety_check(thread)) { 752 // notify parent thread 753 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 754 osthread->set_state(ZOMBIE); 755 sync->notify_all(); 756 return NULL; 757 } 758 759 // thread_id is kernel thread id (similar to Solaris LWP id) 760 osthread->set_thread_id(os::Linux::gettid()); 761 762 if (UseNUMA) { 763 int lgrp_id = os::numa_get_group_id(); 764 if (lgrp_id != -1) { 765 thread->set_lgrp_id(lgrp_id); 766 } 767 } 768 // initialize signal mask for this thread 769 os::Linux::hotspot_sigmask(thread); 770 771 // initialize floating point control register 772 os::Linux::init_thread_fpu_state(); 773 774 // handshaking with parent thread 775 { 776 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 777 778 // notify parent thread 779 osthread->set_state(INITIALIZED); 780 sync->notify_all(); 781 782 // wait until os::start_thread() 783 while (osthread->get_state() == INITIALIZED) { 784 sync->wait(Mutex::_no_safepoint_check_flag); 785 } 786 } 787 788 // call one more level start routine 789 thread->run(); 790 791 return 0; 792 } 793 794 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) { 795 assert(thread->osthread() == NULL, "caller responsible"); 796 797 // Allocate the OSThread object 798 OSThread* osthread = new OSThread(NULL, NULL); 799 if (osthread == NULL) { 800 return false; 801 } 802 803 // set the correct thread state 804 osthread->set_thread_type(thr_type); 805 806 // Initial state is ALLOCATED but not INITIALIZED 807 osthread->set_state(ALLOCATED); 808 809 thread->set_osthread(osthread); 810 811 // init thread attributes 812 pthread_attr_t attr; 813 pthread_attr_init(&attr); 814 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 815 816 // stack size 817 if (os::Linux::supports_variable_stack_size()) { 818 // calculate stack size if it's not specified by caller 819 if (stack_size == 0) { 820 stack_size = os::Linux::default_stack_size(thr_type); 821 822 switch (thr_type) { 823 case os::java_thread: 824 // Java threads use ThreadStackSize which default value can be changed with the flag -Xss 825 if (JavaThread::stack_size_at_create() > 0) stack_size = JavaThread::stack_size_at_create(); 826 break; 827 case os::compiler_thread: 828 if (CompilerThreadStackSize > 0) { 829 stack_size = (size_t)(CompilerThreadStackSize * K); 830 break; 831 } // else fall through: 832 // use VMThreadStackSize if CompilerThreadStackSize is not defined 833 case os::vm_thread: 834 case os::pgc_thread: 835 case os::cgc_thread: 836 case os::watcher_thread: 837 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 838 break; 839 } 840 } 841 842 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 843 pthread_attr_setstacksize(&attr, stack_size); 844 } else { 845 // let pthread_create() pick the default value. 846 } 847 848 // glibc guard page 849 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 850 851 ThreadState state; 852 853 { 854 // Serialize thread creation if we are running with fixed stack LinuxThreads 855 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack(); 856 if (lock) { 857 os::Linux::createThread_lock()->lock_without_safepoint_check(); 858 } 859 860 pthread_t tid; 861 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 862 863 pthread_attr_destroy(&attr); 864 865 if (ret != 0) { 866 if (PrintMiscellaneous && (Verbose || WizardMode)) { 867 perror("pthread_create()"); 868 } 869 // Need to clean up stuff we've allocated so far 870 thread->set_osthread(NULL); 871 delete osthread; 872 if (lock) os::Linux::createThread_lock()->unlock(); 873 return false; 874 } 875 876 // Store pthread info into the OSThread 877 osthread->set_pthread_id(tid); 878 879 // Wait until child thread is either initialized or aborted 880 { 881 Monitor* sync_with_child = osthread->startThread_lock(); 882 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 883 while ((state = osthread->get_state()) == ALLOCATED) { 884 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 885 } 886 } 887 888 if (lock) { 889 os::Linux::createThread_lock()->unlock(); 890 } 891 } 892 893 // Aborted due to thread limit being reached 894 if (state == ZOMBIE) { 895 thread->set_osthread(NULL); 896 delete osthread; 897 return false; 898 } 899 900 // The thread is returned suspended (in state INITIALIZED), 901 // and is started higher up in the call chain 902 assert(state == INITIALIZED, "race condition"); 903 return true; 904 } 905 906 ///////////////////////////////////////////////////////////////////////////// 907 // attach existing thread 908 909 // bootstrap the main thread 910 bool os::create_main_thread(JavaThread* thread) { 911 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 912 return create_attached_thread(thread); 913 } 914 915 bool os::create_attached_thread(JavaThread* thread) { 916 #ifdef ASSERT 917 thread->verify_not_published(); 918 #endif 919 920 // Allocate the OSThread object 921 OSThread* osthread = new OSThread(NULL, NULL); 922 923 if (osthread == NULL) { 924 return false; 925 } 926 927 // Store pthread info into the OSThread 928 osthread->set_thread_id(os::Linux::gettid()); 929 osthread->set_pthread_id(::pthread_self()); 930 931 // initialize floating point control register 932 os::Linux::init_thread_fpu_state(); 933 934 // Initial thread state is RUNNABLE 935 osthread->set_state(RUNNABLE); 936 937 thread->set_osthread(osthread); 938 939 if (UseNUMA) { 940 int lgrp_id = os::numa_get_group_id(); 941 if (lgrp_id != -1) { 942 thread->set_lgrp_id(lgrp_id); 943 } 944 } 945 946 if (os::Linux::is_initial_thread()) { 947 // If current thread is initial thread, its stack is mapped on demand, 948 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 949 // the entire stack region to avoid SEGV in stack banging. 950 // It is also useful to get around the heap-stack-gap problem on SuSE 951 // kernel (see 4821821 for details). We first expand stack to the top 952 // of yellow zone, then enable stack yellow zone (order is significant, 953 // enabling yellow zone first will crash JVM on SuSE Linux), so there 954 // is no gap between the last two virtual memory regions. 955 956 JavaThread *jt = (JavaThread *)thread; 957 address addr = jt->stack_yellow_zone_base(); 958 assert(addr != NULL, "initialization problem?"); 959 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 960 961 osthread->set_expanding_stack(); 962 os::Linux::manually_expand_stack(jt, addr); 963 osthread->clear_expanding_stack(); 964 } 965 966 // initialize signal mask for this thread 967 // and save the caller's signal mask 968 os::Linux::hotspot_sigmask(thread); 969 970 return true; 971 } 972 973 void os::pd_start_thread(Thread* thread) { 974 OSThread * osthread = thread->osthread(); 975 assert(osthread->get_state() != INITIALIZED, "just checking"); 976 Monitor* sync_with_child = osthread->startThread_lock(); 977 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 978 sync_with_child->notify(); 979 } 980 981 // Free Linux resources related to the OSThread 982 void os::free_thread(OSThread* osthread) { 983 assert(osthread != NULL, "osthread not set"); 984 985 if (Thread::current()->osthread() == osthread) { 986 // Restore caller's signal mask 987 sigset_t sigmask = osthread->caller_sigmask(); 988 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 989 } 990 991 delete osthread; 992 } 993 994 ////////////////////////////////////////////////////////////////////////////// 995 // thread local storage 996 997 int os::allocate_thread_local_storage() { 998 pthread_key_t key; 999 int rslt = pthread_key_create(&key, NULL); 1000 assert(rslt == 0, "cannot allocate thread local storage"); 1001 return (int)key; 1002 } 1003 1004 // Note: This is currently not used by VM, as we don't destroy TLS key 1005 // on VM exit. 1006 void os::free_thread_local_storage(int index) { 1007 int rslt = pthread_key_delete((pthread_key_t)index); 1008 assert(rslt == 0, "invalid index"); 1009 } 1010 1011 void os::thread_local_storage_at_put(int index, void* value) { 1012 int rslt = pthread_setspecific((pthread_key_t)index, value); 1013 assert(rslt == 0, "pthread_setspecific failed"); 1014 } 1015 1016 extern "C" Thread* get_thread() { 1017 return ThreadLocalStorage::thread(); 1018 } 1019 1020 ////////////////////////////////////////////////////////////////////////////// 1021 // initial thread 1022 1023 // Check if current thread is the initial thread, similar to Solaris thr_main. 1024 bool os::Linux::is_initial_thread(void) { 1025 char dummy; 1026 // If called before init complete, thread stack bottom will be null. 1027 // Can be called if fatal error occurs before initialization. 1028 if (initial_thread_stack_bottom() == NULL) return false; 1029 assert(initial_thread_stack_bottom() != NULL && 1030 initial_thread_stack_size() != 0, 1031 "os::init did not locate initial thread's stack region"); 1032 if ((address)&dummy >= initial_thread_stack_bottom() && 1033 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) 1034 return true; 1035 else return false; 1036 } 1037 1038 // Find the virtual memory area that contains addr 1039 static bool find_vma(address addr, address* vma_low, address* vma_high) { 1040 FILE *fp = fopen("/proc/self/maps", "r"); 1041 if (fp) { 1042 address low, high; 1043 while (!feof(fp)) { 1044 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1045 if (low <= addr && addr < high) { 1046 if (vma_low) *vma_low = low; 1047 if (vma_high) *vma_high = high; 1048 fclose (fp); 1049 return true; 1050 } 1051 } 1052 for (;;) { 1053 int ch = fgetc(fp); 1054 if (ch == EOF || ch == (int)'\n') break; 1055 } 1056 } 1057 fclose(fp); 1058 } 1059 return false; 1060 } 1061 1062 // Locate initial thread stack. This special handling of initial thread stack 1063 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 1064 // bogus value for initial thread. 1065 void os::Linux::capture_initial_stack(size_t max_size) { 1066 // stack size is the easy part, get it from RLIMIT_STACK 1067 size_t stack_size; 1068 struct rlimit rlim; 1069 getrlimit(RLIMIT_STACK, &rlim); 1070 stack_size = rlim.rlim_cur; 1071 1072 // 6308388: a bug in ld.so will relocate its own .data section to the 1073 // lower end of primordial stack; reduce ulimit -s value a little bit 1074 // so we won't install guard page on ld.so's data section. 1075 stack_size -= 2 * page_size(); 1076 1077 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 1078 // 7.1, in both cases we will get 2G in return value. 1079 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 1080 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 1081 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 1082 // in case other parts in glibc still assumes 2M max stack size. 1083 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 1084 #ifndef IA64 1085 if (stack_size > 2 * K * K) stack_size = 2 * K * K; 1086 #else 1087 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 1088 if (stack_size > 4 * K * K) stack_size = 4 * K * K; 1089 #endif 1090 1091 // Try to figure out where the stack base (top) is. This is harder. 1092 // 1093 // When an application is started, glibc saves the initial stack pointer in 1094 // a global variable "__libc_stack_end", which is then used by system 1095 // libraries. __libc_stack_end should be pretty close to stack top. The 1096 // variable is available since the very early days. However, because it is 1097 // a private interface, it could disappear in the future. 1098 // 1099 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1100 // to __libc_stack_end, it is very close to stack top, but isn't the real 1101 // stack top. Note that /proc may not exist if VM is running as a chroot 1102 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1103 // /proc/<pid>/stat could change in the future (though unlikely). 1104 // 1105 // We try __libc_stack_end first. If that doesn't work, look for 1106 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1107 // as a hint, which should work well in most cases. 1108 1109 uintptr_t stack_start; 1110 1111 // try __libc_stack_end first 1112 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1113 if (p && *p) { 1114 stack_start = *p; 1115 } else { 1116 // see if we can get the start_stack field from /proc/self/stat 1117 FILE *fp; 1118 int pid; 1119 char state; 1120 int ppid; 1121 int pgrp; 1122 int session; 1123 int nr; 1124 int tpgrp; 1125 unsigned long flags; 1126 unsigned long minflt; 1127 unsigned long cminflt; 1128 unsigned long majflt; 1129 unsigned long cmajflt; 1130 unsigned long utime; 1131 unsigned long stime; 1132 long cutime; 1133 long cstime; 1134 long prio; 1135 long nice; 1136 long junk; 1137 long it_real; 1138 uintptr_t start; 1139 uintptr_t vsize; 1140 uintptr_t rss; 1141 unsigned long rsslim; 1142 uintptr_t scodes; 1143 uintptr_t ecode; 1144 int i; 1145 1146 // Figure what the primordial thread stack base is. Code is inspired 1147 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1148 // followed by command name surrounded by parentheses, state, etc. 1149 char stat[2048]; 1150 int statlen; 1151 1152 fp = fopen("/proc/self/stat", "r"); 1153 if (fp) { 1154 statlen = fread(stat, 1, 2047, fp); 1155 stat[statlen] = '\0'; 1156 fclose(fp); 1157 1158 // Skip pid and the command string. Note that we could be dealing with 1159 // weird command names, e.g. user could decide to rename java launcher 1160 // to "java 1.4.2 :)", then the stat file would look like 1161 // 1234 (java 1.4.2 :)) R ... ... 1162 // We don't really need to know the command string, just find the last 1163 // occurrence of ")" and then start parsing from there. See bug 4726580. 1164 char * s = strrchr(stat, ')'); 1165 1166 i = 0; 1167 if (s) { 1168 // Skip blank chars 1169 do s++; while (isspace(*s)); 1170 1171 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */ 1172 /* 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 */ 1173 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " 1174 UINTX_FORMAT UINTX_FORMAT UINTX_FORMAT 1175 " %lu " 1176 UINTX_FORMAT UINTX_FORMAT UINTX_FORMAT, 1177 &state, /* 3 %c */ 1178 &ppid, /* 4 %d */ 1179 &pgrp, /* 5 %d */ 1180 &session, /* 6 %d */ 1181 &nr, /* 7 %d */ 1182 &tpgrp, /* 8 %d */ 1183 &flags, /* 9 %lu */ 1184 &minflt, /* 10 %lu */ 1185 &cminflt, /* 11 %lu */ 1186 &majflt, /* 12 %lu */ 1187 &cmajflt, /* 13 %lu */ 1188 &utime, /* 14 %lu */ 1189 &stime, /* 15 %lu */ 1190 &cutime, /* 16 %ld */ 1191 &cstime, /* 17 %ld */ 1192 &prio, /* 18 %ld */ 1193 &nice, /* 19 %ld */ 1194 &junk, /* 20 %ld */ 1195 &it_real, /* 21 %ld */ 1196 &start, /* 22 UINTX_FORMAT */ 1197 &vsize, /* 23 UINTX_FORMAT */ 1198 &rss, /* 24 UINTX_FORMAT */ 1199 &rsslim, /* 25 %lu */ 1200 &scodes, /* 26 UINTX_FORMAT */ 1201 &ecode, /* 27 UINTX_FORMAT */ 1202 &stack_start); /* 28 UINTX_FORMAT */ 1203 } 1204 1205 if (i != 28 - 2) { 1206 assert(false, "Bad conversion from /proc/self/stat"); 1207 // product mode - assume we are the initial thread, good luck in the 1208 // embedded case. 1209 warning("Can't detect initial thread stack location - bad conversion"); 1210 stack_start = (uintptr_t) &rlim; 1211 } 1212 } else { 1213 // For some reason we can't open /proc/self/stat (for example, running on 1214 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1215 // most cases, so don't abort: 1216 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1217 stack_start = (uintptr_t) &rlim; 1218 } 1219 } 1220 1221 // Now we have a pointer (stack_start) very close to the stack top, the 1222 // next thing to do is to figure out the exact location of stack top. We 1223 // can find out the virtual memory area that contains stack_start by 1224 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1225 // and its upper limit is the real stack top. (again, this would fail if 1226 // running inside chroot, because /proc may not exist.) 1227 1228 uintptr_t stack_top; 1229 address low, high; 1230 if (find_vma((address)stack_start, &low, &high)) { 1231 // success, "high" is the true stack top. (ignore "low", because initial 1232 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1233 stack_top = (uintptr_t)high; 1234 } else { 1235 // failed, likely because /proc/self/maps does not exist 1236 warning("Can't detect initial thread stack location - find_vma failed"); 1237 // best effort: stack_start is normally within a few pages below the real 1238 // stack top, use it as stack top, and reduce stack size so we won't put 1239 // guard page outside stack. 1240 stack_top = stack_start; 1241 stack_size -= 16 * page_size(); 1242 } 1243 1244 // stack_top could be partially down the page so align it 1245 stack_top = align_size_up(stack_top, page_size()); 1246 1247 if (max_size && stack_size > max_size) { 1248 _initial_thread_stack_size = max_size; 1249 } else { 1250 _initial_thread_stack_size = stack_size; 1251 } 1252 1253 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1254 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1255 } 1256 1257 //////////////////////////////////////////////////////////////////////////////// 1258 // time support 1259 1260 // Time since start-up in seconds to a fine granularity. 1261 // Used by VMSelfDestructTimer and the MemProfiler. 1262 double os::elapsedTime() { 1263 1264 return (double)(os::elapsed_counter()) * 0.000001; 1265 } 1266 1267 jlong os::elapsed_counter() { 1268 timeval time; 1269 int status = gettimeofday(&time, NULL); 1270 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count; 1271 } 1272 1273 jlong os::elapsed_frequency() { 1274 return (1000 * 1000); 1275 } 1276 1277 // For now, we say that linux does not support vtime. I have no idea 1278 // whether it can actually be made to (DLD, 9/13/05). 1279 1280 bool os::supports_vtime() { return false; } 1281 bool os::enable_vtime() { return false; } 1282 bool os::vtime_enabled() { return false; } 1283 double os::elapsedVTime() { 1284 // better than nothing, but not much 1285 return elapsedTime(); 1286 } 1287 1288 jlong os::javaTimeMillis() { 1289 timeval time; 1290 int status = gettimeofday(&time, NULL); 1291 assert(status != -1, "linux error"); 1292 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1293 } 1294 1295 #ifndef CLOCK_MONOTONIC 1296 #define CLOCK_MONOTONIC (1) 1297 #endif 1298 1299 void os::Linux::clock_init() { 1300 // we do dlopen's in this particular order due to bug in linux 1301 // dynamical loader (see 6348968) leading to crash on exit 1302 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1303 if (handle == NULL) { 1304 handle = dlopen("librt.so", RTLD_LAZY); 1305 } 1306 1307 if (handle) { 1308 int (*clock_getres_func)(clockid_t, struct timespec*) = 1309 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1310 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1311 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1312 if (clock_getres_func && clock_gettime_func) { 1313 // See if monotonic clock is supported by the kernel. Note that some 1314 // early implementations simply return kernel jiffies (updated every 1315 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1316 // for nano time (though the monotonic property is still nice to have). 1317 // It's fixed in newer kernels, however clock_getres() still returns 1318 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1319 // resolution for now. Hopefully as people move to new kernels, this 1320 // won't be a problem. 1321 struct timespec res; 1322 struct timespec tp; 1323 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1324 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1325 // yes, monotonic clock is supported 1326 _clock_gettime = clock_gettime_func; 1327 } else { 1328 // close librt if there is no monotonic clock 1329 dlclose(handle); 1330 } 1331 } 1332 } 1333 } 1334 1335 #ifndef SYS_clock_getres 1336 1337 #if defined(IA32) || defined(AMD64) 1338 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1339 #else 1340 #error Value of SYS_clock_getres not known on this platform 1341 #endif 1342 1343 #endif 1344 1345 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1346 1347 void os::Linux::fast_thread_clock_init() { 1348 if (!UseLinuxPosixThreadCPUClocks) { 1349 return; 1350 } 1351 clockid_t clockid; 1352 struct timespec tp; 1353 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1354 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1355 1356 // Switch to using fast clocks for thread cpu time if 1357 // the sys_clock_getres() returns 0 error code. 1358 // Note, that some kernels may support the current thread 1359 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1360 // returned by the pthread_getcpuclockid(). 1361 // If the fast Posix clocks are supported then the sys_clock_getres() 1362 // must return at least tp.tv_sec == 0 which means a resolution 1363 // better than 1 sec. This is extra check for reliability. 1364 1365 if(pthread_getcpuclockid_func && 1366 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1367 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1368 1369 _supports_fast_thread_cpu_time = true; 1370 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1371 } 1372 } 1373 1374 jlong os::javaTimeNanos() { 1375 if (Linux::supports_monotonic_clock()) { 1376 struct timespec tp; 1377 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1378 assert(status == 0, "gettime error"); 1379 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1380 return result; 1381 } else { 1382 timeval time; 1383 int status = gettimeofday(&time, NULL); 1384 assert(status != -1, "linux error"); 1385 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1386 return 1000 * usecs; 1387 } 1388 } 1389 1390 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1391 if (Linux::supports_monotonic_clock()) { 1392 info_ptr->max_value = ALL_64_BITS; 1393 1394 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1395 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1396 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1397 } else { 1398 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1399 info_ptr->max_value = ALL_64_BITS; 1400 1401 // gettimeofday is a real time clock so it skips 1402 info_ptr->may_skip_backward = true; 1403 info_ptr->may_skip_forward = true; 1404 } 1405 1406 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1407 } 1408 1409 // Return the real, user, and system times in seconds from an 1410 // arbitrary fixed point in the past. 1411 bool os::getTimesSecs(double* process_real_time, 1412 double* process_user_time, 1413 double* process_system_time) { 1414 struct tms ticks; 1415 clock_t real_ticks = times(&ticks); 1416 1417 if (real_ticks == (clock_t) (-1)) { 1418 return false; 1419 } else { 1420 double ticks_per_second = (double) clock_tics_per_sec; 1421 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1422 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1423 *process_real_time = ((double) real_ticks) / ticks_per_second; 1424 1425 return true; 1426 } 1427 } 1428 1429 1430 char * os::local_time_string(char *buf, size_t buflen) { 1431 struct tm t; 1432 time_t long_time; 1433 time(&long_time); 1434 localtime_r(&long_time, &t); 1435 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1436 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1437 t.tm_hour, t.tm_min, t.tm_sec); 1438 return buf; 1439 } 1440 1441 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1442 return localtime_r(clock, res); 1443 } 1444 1445 //////////////////////////////////////////////////////////////////////////////// 1446 // runtime exit support 1447 1448 // Note: os::shutdown() might be called very early during initialization, or 1449 // called from signal handler. Before adding something to os::shutdown(), make 1450 // sure it is async-safe and can handle partially initialized VM. 1451 void os::shutdown() { 1452 1453 // allow PerfMemory to attempt cleanup of any persistent resources 1454 perfMemory_exit(); 1455 1456 // needs to remove object in file system 1457 AttachListener::abort(); 1458 1459 // flush buffered output, finish log files 1460 ostream_abort(); 1461 1462 // Check for abort hook 1463 abort_hook_t abort_hook = Arguments::abort_hook(); 1464 if (abort_hook != NULL) { 1465 abort_hook(); 1466 } 1467 1468 } 1469 1470 // Note: os::abort() might be called very early during initialization, or 1471 // called from signal handler. Before adding something to os::abort(), make 1472 // sure it is async-safe and can handle partially initialized VM. 1473 void os::abort(bool dump_core) { 1474 os::shutdown(); 1475 if (dump_core) { 1476 #ifndef PRODUCT 1477 fdStream out(defaultStream::output_fd()); 1478 out.print_raw("Current thread is "); 1479 char buf[16]; 1480 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1481 out.print_raw_cr(buf); 1482 out.print_raw_cr("Dumping core ..."); 1483 #endif 1484 ::abort(); // dump core 1485 } 1486 1487 ::exit(1); 1488 } 1489 1490 // Die immediately, no exit hook, no abort hook, no cleanup. 1491 void os::die() { 1492 // _exit() on LinuxThreads only kills current thread 1493 ::abort(); 1494 } 1495 1496 // unused on linux for now. 1497 void os::set_error_file(const char *logfile) {} 1498 1499 intx os::current_thread_id() { return (intx)pthread_self(); } 1500 int os::current_process_id() { 1501 1502 // Under the old linux thread library, linux gives each thread 1503 // its own process id. Because of this each thread will return 1504 // a different pid if this method were to return the result 1505 // of getpid(2). Linux provides no api that returns the pid 1506 // of the launcher thread for the vm. This implementation 1507 // returns a unique pid, the pid of the launcher thread 1508 // that starts the vm 'process'. 1509 1510 // Under the NPTL, getpid() returns the same pid as the 1511 // launcher thread rather than a unique pid per thread. 1512 // Use gettid() if you want the old pre NPTL behaviour. 1513 1514 // if you are looking for the result of a call to getpid() that 1515 // returns a unique pid for the calling thread, then look at the 1516 // OSThread::thread_id() method in osThread_linux.hpp file 1517 1518 return (int)(_initial_pid ? _initial_pid : getpid()); 1519 } 1520 1521 // DLL functions 1522 1523 const char* os::dll_file_extension() { return ".so"; } 1524 1525 const char* os::get_temp_directory() { return "/tmp/"; } 1526 1527 static bool file_exists(const char* filename) { 1528 struct stat statbuf; 1529 if (filename == NULL || strlen(filename) == 0) { 1530 return false; 1531 } 1532 return os::stat(filename, &statbuf) == 0; 1533 } 1534 1535 void os::dll_build_name(char* buffer, size_t buflen, 1536 const char* pname, const char* fname) { 1537 // Copied from libhpi 1538 const size_t pnamelen = pname ? strlen(pname) : 0; 1539 1540 // Quietly truncate on buffer overflow. Should be an error. 1541 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1542 *buffer = '\0'; 1543 return; 1544 } 1545 1546 if (pnamelen == 0) { 1547 snprintf(buffer, buflen, "lib%s.so", fname); 1548 } else if (strchr(pname, *os::path_separator()) != NULL) { 1549 int n; 1550 char** pelements = split_path(pname, &n); 1551 for (int i = 0 ; i < n ; i++) { 1552 // Really shouldn't be NULL, but check can't hurt 1553 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1554 continue; // skip the empty path values 1555 } 1556 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1557 if (file_exists(buffer)) { 1558 break; 1559 } 1560 } 1561 // release the storage 1562 for (int i = 0 ; i < n ; i++) { 1563 if (pelements[i] != NULL) { 1564 FREE_C_HEAP_ARRAY(char, pelements[i]); 1565 } 1566 } 1567 if (pelements != NULL) { 1568 FREE_C_HEAP_ARRAY(char*, pelements); 1569 } 1570 } else { 1571 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1572 } 1573 } 1574 1575 const char* os::get_current_directory(char *buf, int buflen) { 1576 return getcwd(buf, buflen); 1577 } 1578 1579 // check if addr is inside libjvm[_g].so 1580 bool os::address_is_in_vm(address addr) { 1581 static address libjvm_base_addr; 1582 Dl_info dlinfo; 1583 1584 if (libjvm_base_addr == NULL) { 1585 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo); 1586 libjvm_base_addr = (address)dlinfo.dli_fbase; 1587 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1588 } 1589 1590 if (dladdr((void *)addr, &dlinfo)) { 1591 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1592 } 1593 1594 return false; 1595 } 1596 1597 bool os::dll_address_to_function_name(address addr, char *buf, 1598 int buflen, int *offset) { 1599 Dl_info dlinfo; 1600 1601 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) { 1602 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1603 if (offset) *offset = addr - (address)dlinfo.dli_saddr; 1604 return true; 1605 } else { 1606 if (buf) buf[0] = '\0'; 1607 if (offset) *offset = -1; 1608 return false; 1609 } 1610 } 1611 1612 struct _address_to_library_name { 1613 address addr; // input : memory address 1614 size_t buflen; // size of fname 1615 char* fname; // output: library name 1616 address base; // library base addr 1617 }; 1618 1619 static int address_to_library_name_callback(struct dl_phdr_info *info, 1620 size_t size, void *data) { 1621 int i; 1622 bool found = false; 1623 address libbase = NULL; 1624 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1625 1626 // iterate through all loadable segments 1627 for (i = 0; i < info->dlpi_phnum; i++) { 1628 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1629 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1630 // base address of a library is the lowest address of its loaded 1631 // segments. 1632 if (libbase == NULL || libbase > segbase) { 1633 libbase = segbase; 1634 } 1635 // see if 'addr' is within current segment 1636 if (segbase <= d->addr && 1637 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1638 found = true; 1639 } 1640 } 1641 } 1642 1643 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1644 // so dll_address_to_library_name() can fall through to use dladdr() which 1645 // can figure out executable name from argv[0]. 1646 if (found && info->dlpi_name && info->dlpi_name[0]) { 1647 d->base = libbase; 1648 if (d->fname) { 1649 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1650 } 1651 return 1; 1652 } 1653 return 0; 1654 } 1655 1656 bool os::dll_address_to_library_name(address addr, char* buf, 1657 int buflen, int* offset) { 1658 Dl_info dlinfo; 1659 struct _address_to_library_name data; 1660 1661 // There is a bug in old glibc dladdr() implementation that it could resolve 1662 // to wrong library name if the .so file has a base address != NULL. Here 1663 // we iterate through the program headers of all loaded libraries to find 1664 // out which library 'addr' really belongs to. This workaround can be 1665 // removed once the minimum requirement for glibc is moved to 2.3.x. 1666 data.addr = addr; 1667 data.fname = buf; 1668 data.buflen = buflen; 1669 data.base = NULL; 1670 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1671 1672 if (rslt) { 1673 // buf already contains library name 1674 if (offset) *offset = addr - data.base; 1675 return true; 1676 } else if (dladdr((void*)addr, &dlinfo)){ 1677 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1678 if (offset) *offset = addr - (address)dlinfo.dli_fbase; 1679 return true; 1680 } else { 1681 if (buf) buf[0] = '\0'; 1682 if (offset) *offset = -1; 1683 return false; 1684 } 1685 } 1686 1687 // Loads .dll/.so and 1688 // in case of error it checks if .dll/.so was built for the 1689 // same architecture as Hotspot is running on 1690 1691 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) 1692 { 1693 void * result= ::dlopen(filename, RTLD_LAZY); 1694 if (result != NULL) { 1695 // Successful loading 1696 return result; 1697 } 1698 1699 Elf32_Ehdr elf_head; 1700 1701 // Read system error message into ebuf 1702 // It may or may not be overwritten below 1703 ::strncpy(ebuf, ::dlerror(), ebuflen-1); 1704 ebuf[ebuflen-1]='\0'; 1705 int diag_msg_max_length=ebuflen-strlen(ebuf); 1706 char* diag_msg_buf=ebuf+strlen(ebuf); 1707 1708 if (diag_msg_max_length==0) { 1709 // No more space in ebuf for additional diagnostics message 1710 return NULL; 1711 } 1712 1713 1714 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1715 1716 if (file_descriptor < 0) { 1717 // Can't open library, report dlerror() message 1718 return NULL; 1719 } 1720 1721 bool failed_to_read_elf_head= 1722 (sizeof(elf_head)!= 1723 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ; 1724 1725 ::close(file_descriptor); 1726 if (failed_to_read_elf_head) { 1727 // file i/o error - report dlerror() msg 1728 return NULL; 1729 } 1730 1731 typedef struct { 1732 Elf32_Half code; // Actual value as defined in elf.h 1733 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1734 char elf_class; // 32 or 64 bit 1735 char endianess; // MSB or LSB 1736 char* name; // String representation 1737 } arch_t; 1738 1739 #ifndef EM_486 1740 #define EM_486 6 /* Intel 80486 */ 1741 #endif 1742 1743 static const arch_t arch_array[]={ 1744 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1745 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1746 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1747 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1748 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1749 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1750 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1751 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1752 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1753 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1754 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1755 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1756 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1757 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1758 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1759 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"} 1760 }; 1761 1762 #if (defined IA32) 1763 static Elf32_Half running_arch_code=EM_386; 1764 #elif (defined AMD64) 1765 static Elf32_Half running_arch_code=EM_X86_64; 1766 #elif (defined IA64) 1767 static Elf32_Half running_arch_code=EM_IA_64; 1768 #elif (defined __sparc) && (defined _LP64) 1769 static Elf32_Half running_arch_code=EM_SPARCV9; 1770 #elif (defined __sparc) && (!defined _LP64) 1771 static Elf32_Half running_arch_code=EM_SPARC; 1772 #elif (defined __powerpc64__) 1773 static Elf32_Half running_arch_code=EM_PPC64; 1774 #elif (defined __powerpc__) 1775 static Elf32_Half running_arch_code=EM_PPC; 1776 #elif (defined ARM) 1777 static Elf32_Half running_arch_code=EM_ARM; 1778 #elif (defined S390) 1779 static Elf32_Half running_arch_code=EM_S390; 1780 #elif (defined ALPHA) 1781 static Elf32_Half running_arch_code=EM_ALPHA; 1782 #elif (defined MIPSEL) 1783 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1784 #elif (defined PARISC) 1785 static Elf32_Half running_arch_code=EM_PARISC; 1786 #elif (defined MIPS) 1787 static Elf32_Half running_arch_code=EM_MIPS; 1788 #elif (defined M68K) 1789 static Elf32_Half running_arch_code=EM_68K; 1790 #else 1791 #error Method os::dll_load requires that one of following is defined:\ 1792 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K 1793 #endif 1794 1795 // Identify compatability class for VM's architecture and library's architecture 1796 // Obtain string descriptions for architectures 1797 1798 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1799 int running_arch_index=-1; 1800 1801 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) { 1802 if (running_arch_code == arch_array[i].code) { 1803 running_arch_index = i; 1804 } 1805 if (lib_arch.code == arch_array[i].code) { 1806 lib_arch.compat_class = arch_array[i].compat_class; 1807 lib_arch.name = arch_array[i].name; 1808 } 1809 } 1810 1811 assert(running_arch_index != -1, 1812 "Didn't find running architecture code (running_arch_code) in arch_array"); 1813 if (running_arch_index == -1) { 1814 // Even though running architecture detection failed 1815 // we may still continue with reporting dlerror() message 1816 return NULL; 1817 } 1818 1819 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1820 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1821 return NULL; 1822 } 1823 1824 #ifndef S390 1825 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1826 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1827 return NULL; 1828 } 1829 #endif // !S390 1830 1831 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1832 if ( lib_arch.name!=NULL ) { 1833 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1834 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1835 lib_arch.name, arch_array[running_arch_index].name); 1836 } else { 1837 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1838 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1839 lib_arch.code, 1840 arch_array[running_arch_index].name); 1841 } 1842 } 1843 1844 return NULL; 1845 } 1846 1847 /* 1848 * glibc-2.0 libdl is not MT safe. If you are building with any glibc, 1849 * chances are you might want to run the generated bits against glibc-2.0 1850 * libdl.so, so always use locking for any version of glibc. 1851 */ 1852 void* os::dll_lookup(void* handle, const char* name) { 1853 pthread_mutex_lock(&dl_mutex); 1854 void* res = dlsym(handle, name); 1855 pthread_mutex_unlock(&dl_mutex); 1856 return res; 1857 } 1858 1859 1860 bool _print_ascii_file(const char* filename, outputStream* st) { 1861 int fd = open(filename, O_RDONLY); 1862 if (fd == -1) { 1863 return false; 1864 } 1865 1866 char buf[32]; 1867 int bytes; 1868 while ((bytes = read(fd, buf, sizeof(buf))) > 0) { 1869 st->print_raw(buf, bytes); 1870 } 1871 1872 close(fd); 1873 1874 return true; 1875 } 1876 1877 void os::print_dll_info(outputStream *st) { 1878 st->print_cr("Dynamic libraries:"); 1879 1880 char fname[32]; 1881 pid_t pid = os::Linux::gettid(); 1882 1883 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1884 1885 if (!_print_ascii_file(fname, st)) { 1886 st->print("Can not get library information for pid = %d\n", pid); 1887 } 1888 } 1889 1890 1891 void os::print_os_info(outputStream* st) { 1892 st->print("OS:"); 1893 1894 // Try to identify popular distros. 1895 // Most Linux distributions have /etc/XXX-release file, which contains 1896 // the OS version string. Some have more than one /etc/XXX-release file 1897 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.), 1898 // so the order is important. 1899 if (!_print_ascii_file("/etc/mandrake-release", st) && 1900 !_print_ascii_file("/etc/sun-release", st) && 1901 !_print_ascii_file("/etc/redhat-release", st) && 1902 !_print_ascii_file("/etc/SuSE-release", st) && 1903 !_print_ascii_file("/etc/turbolinux-release", st) && 1904 !_print_ascii_file("/etc/gentoo-release", st) && 1905 !_print_ascii_file("/etc/debian_version", st)) { 1906 st->print("Linux"); 1907 } 1908 st->cr(); 1909 1910 // kernel 1911 st->print("uname:"); 1912 struct utsname name; 1913 uname(&name); 1914 st->print(name.sysname); st->print(" "); 1915 st->print(name.release); st->print(" "); 1916 st->print(name.version); st->print(" "); 1917 st->print(name.machine); 1918 st->cr(); 1919 1920 // Print warning if unsafe chroot environment detected 1921 if (unsafe_chroot_detected) { 1922 st->print("WARNING!! "); 1923 st->print_cr(unstable_chroot_error); 1924 } 1925 1926 // libc, pthread 1927 st->print("libc:"); 1928 st->print(os::Linux::glibc_version()); st->print(" "); 1929 st->print(os::Linux::libpthread_version()); st->print(" "); 1930 if (os::Linux::is_LinuxThreads()) { 1931 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed"); 1932 } 1933 st->cr(); 1934 1935 // rlimit 1936 st->print("rlimit:"); 1937 struct rlimit rlim; 1938 1939 st->print(" STACK "); 1940 getrlimit(RLIMIT_STACK, &rlim); 1941 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 1942 else st->print("%uk", rlim.rlim_cur >> 10); 1943 1944 st->print(", CORE "); 1945 getrlimit(RLIMIT_CORE, &rlim); 1946 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 1947 else st->print("%uk", rlim.rlim_cur >> 10); 1948 1949 st->print(", NPROC "); 1950 getrlimit(RLIMIT_NPROC, &rlim); 1951 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 1952 else st->print("%d", rlim.rlim_cur); 1953 1954 st->print(", NOFILE "); 1955 getrlimit(RLIMIT_NOFILE, &rlim); 1956 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 1957 else st->print("%d", rlim.rlim_cur); 1958 1959 st->print(", AS "); 1960 getrlimit(RLIMIT_AS, &rlim); 1961 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 1962 else st->print("%uk", rlim.rlim_cur >> 10); 1963 st->cr(); 1964 1965 // load average 1966 st->print("load average:"); 1967 double loadavg[3]; 1968 os::loadavg(loadavg, 3); 1969 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]); 1970 st->cr(); 1971 } 1972 1973 void os::print_memory_info(outputStream* st) { 1974 1975 st->print("Memory:"); 1976 st->print(" %dk page", os::vm_page_size()>>10); 1977 1978 // values in struct sysinfo are "unsigned long" 1979 struct sysinfo si; 1980 sysinfo(&si); 1981 1982 st->print(", physical " UINT64_FORMAT "k", 1983 os::physical_memory() >> 10); 1984 st->print("(" UINT64_FORMAT "k free)", 1985 os::available_memory() >> 10); 1986 st->print(", swap " UINT64_FORMAT "k", 1987 ((jlong)si.totalswap * si.mem_unit) >> 10); 1988 st->print("(" UINT64_FORMAT "k free)", 1989 ((jlong)si.freeswap * si.mem_unit) >> 10); 1990 st->cr(); 1991 } 1992 1993 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific 1994 // but they're the same for all the linux arch that we support 1995 // and they're the same for solaris but there's no common place to put this. 1996 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR", 1997 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG", 1998 "ILL_COPROC", "ILL_BADSTK" }; 1999 2000 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV", 2001 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES", 2002 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" }; 2003 2004 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" }; 2005 2006 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" }; 2007 2008 void os::print_siginfo(outputStream* st, void* siginfo) { 2009 st->print("siginfo:"); 2010 2011 const int buflen = 100; 2012 char buf[buflen]; 2013 siginfo_t *si = (siginfo_t*)siginfo; 2014 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen)); 2015 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) { 2016 st->print("si_errno=%s", buf); 2017 } else { 2018 st->print("si_errno=%d", si->si_errno); 2019 } 2020 const int c = si->si_code; 2021 assert(c > 0, "unexpected si_code"); 2022 switch (si->si_signo) { 2023 case SIGILL: 2024 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]); 2025 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2026 break; 2027 case SIGFPE: 2028 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]); 2029 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2030 break; 2031 case SIGSEGV: 2032 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]); 2033 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2034 break; 2035 case SIGBUS: 2036 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]); 2037 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2038 break; 2039 default: 2040 st->print(", si_code=%d", si->si_code); 2041 // no si_addr 2042 } 2043 2044 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2045 UseSharedSpaces) { 2046 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2047 if (mapinfo->is_in_shared_space(si->si_addr)) { 2048 st->print("\n\nError accessing class data sharing archive." \ 2049 " Mapped file inaccessible during execution, " \ 2050 " possible disk/network problem."); 2051 } 2052 } 2053 st->cr(); 2054 } 2055 2056 2057 static void print_signal_handler(outputStream* st, int sig, 2058 char* buf, size_t buflen); 2059 2060 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2061 st->print_cr("Signal Handlers:"); 2062 print_signal_handler(st, SIGSEGV, buf, buflen); 2063 print_signal_handler(st, SIGBUS , buf, buflen); 2064 print_signal_handler(st, SIGFPE , buf, buflen); 2065 print_signal_handler(st, SIGPIPE, buf, buflen); 2066 print_signal_handler(st, SIGXFSZ, buf, buflen); 2067 print_signal_handler(st, SIGILL , buf, buflen); 2068 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2069 print_signal_handler(st, SR_signum, buf, buflen); 2070 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2071 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2072 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2073 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2074 } 2075 2076 static char saved_jvm_path[MAXPATHLEN] = {0}; 2077 2078 // Find the full path to the current module, libjvm.so or libjvm_g.so 2079 void os::jvm_path(char *buf, jint len) { 2080 // Error checking. 2081 if (len < MAXPATHLEN) { 2082 assert(false, "must use a large-enough buffer"); 2083 buf[0] = '\0'; 2084 return; 2085 } 2086 // Lazy resolve the path to current module. 2087 if (saved_jvm_path[0] != 0) { 2088 strcpy(buf, saved_jvm_path); 2089 return; 2090 } 2091 2092 char dli_fname[MAXPATHLEN]; 2093 bool ret = dll_address_to_library_name( 2094 CAST_FROM_FN_PTR(address, os::jvm_path), 2095 dli_fname, sizeof(dli_fname), NULL); 2096 assert(ret != 0, "cannot locate libjvm"); 2097 if (realpath(dli_fname, buf) == NULL) 2098 return; 2099 2100 if (strcmp(Arguments::sun_java_launcher(), "gamma") == 0) { 2101 // Support for the gamma launcher. Typical value for buf is 2102 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at 2103 // the right place in the string, then assume we are installed in a JDK and 2104 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix 2105 // up the path so it looks like libjvm.so is installed there (append a 2106 // fake suffix hotspot/libjvm.so). 2107 const char *p = buf + strlen(buf) - 1; 2108 for (int count = 0; p > buf && count < 5; ++count) { 2109 for (--p; p > buf && *p != '/'; --p) 2110 /* empty */ ; 2111 } 2112 2113 if (strncmp(p, "/jre/lib/", 9) != 0) { 2114 // Look for JAVA_HOME in the environment. 2115 char* java_home_var = ::getenv("JAVA_HOME"); 2116 if (java_home_var != NULL && java_home_var[0] != 0) { 2117 // Check the current module name "libjvm.so" or "libjvm_g.so". 2118 p = strrchr(buf, '/'); 2119 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2120 p = strstr(p, "_g") ? "_g" : ""; 2121 2122 if (realpath(java_home_var, buf) == NULL) 2123 return; 2124 sprintf(buf + strlen(buf), "/jre/lib/%s", cpu_arch); 2125 if (0 == access(buf, F_OK)) { 2126 // Use current module name "libjvm[_g].so" instead of 2127 // "libjvm"debug_only("_g")".so" since for fastdebug version 2128 // we should have "libjvm.so" but debug_only("_g") adds "_g"! 2129 // It is used when we are choosing the HPI library's name 2130 // "libhpi[_g].so" in hpi::initialize_get_interface(). 2131 sprintf(buf + strlen(buf), "/hotspot/libjvm%s.so", p); 2132 } else { 2133 // Go back to path of .so 2134 if (realpath(dli_fname, buf) == NULL) 2135 return; 2136 } 2137 } 2138 } 2139 } 2140 2141 strcpy(saved_jvm_path, buf); 2142 } 2143 2144 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2145 // no prefix required, not even "_" 2146 } 2147 2148 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2149 // no suffix required 2150 } 2151 2152 //////////////////////////////////////////////////////////////////////////////// 2153 // sun.misc.Signal support 2154 2155 static volatile jint sigint_count = 0; 2156 2157 static void 2158 UserHandler(int sig, void *siginfo, void *context) { 2159 // 4511530 - sem_post is serialized and handled by the manager thread. When 2160 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2161 // don't want to flood the manager thread with sem_post requests. 2162 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) 2163 return; 2164 2165 // Ctrl-C is pressed during error reporting, likely because the error 2166 // handler fails to abort. Let VM die immediately. 2167 if (sig == SIGINT && is_error_reported()) { 2168 os::die(); 2169 } 2170 2171 os::signal_notify(sig); 2172 } 2173 2174 void* os::user_handler() { 2175 return CAST_FROM_FN_PTR(void*, UserHandler); 2176 } 2177 2178 extern "C" { 2179 typedef void (*sa_handler_t)(int); 2180 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2181 } 2182 2183 void* os::signal(int signal_number, void* handler) { 2184 struct sigaction sigAct, oldSigAct; 2185 2186 sigfillset(&(sigAct.sa_mask)); 2187 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2188 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2189 2190 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2191 // -1 means registration failed 2192 return (void *)-1; 2193 } 2194 2195 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2196 } 2197 2198 void os::signal_raise(int signal_number) { 2199 ::raise(signal_number); 2200 } 2201 2202 /* 2203 * The following code is moved from os.cpp for making this 2204 * code platform specific, which it is by its very nature. 2205 */ 2206 2207 // Will be modified when max signal is changed to be dynamic 2208 int os::sigexitnum_pd() { 2209 return NSIG; 2210 } 2211 2212 // a counter for each possible signal value 2213 static volatile jint pending_signals[NSIG+1] = { 0 }; 2214 2215 // Linux(POSIX) specific hand shaking semaphore. 2216 static sem_t sig_sem; 2217 2218 void os::signal_init_pd() { 2219 // Initialize signal structures 2220 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2221 2222 // Initialize signal semaphore 2223 ::sem_init(&sig_sem, 0, 0); 2224 } 2225 2226 void os::signal_notify(int sig) { 2227 Atomic::inc(&pending_signals[sig]); 2228 ::sem_post(&sig_sem); 2229 } 2230 2231 static int check_pending_signals(bool wait) { 2232 Atomic::store(0, &sigint_count); 2233 for (;;) { 2234 for (int i = 0; i < NSIG + 1; i++) { 2235 jint n = pending_signals[i]; 2236 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2237 return i; 2238 } 2239 } 2240 if (!wait) { 2241 return -1; 2242 } 2243 JavaThread *thread = JavaThread::current(); 2244 ThreadBlockInVM tbivm(thread); 2245 2246 bool threadIsSuspended; 2247 do { 2248 thread->set_suspend_equivalent(); 2249 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2250 ::sem_wait(&sig_sem); 2251 2252 // were we externally suspended while we were waiting? 2253 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2254 if (threadIsSuspended) { 2255 // 2256 // The semaphore has been incremented, but while we were waiting 2257 // another thread suspended us. We don't want to continue running 2258 // while suspended because that would surprise the thread that 2259 // suspended us. 2260 // 2261 ::sem_post(&sig_sem); 2262 2263 thread->java_suspend_self(); 2264 } 2265 } while (threadIsSuspended); 2266 } 2267 } 2268 2269 int os::signal_lookup() { 2270 return check_pending_signals(false); 2271 } 2272 2273 int os::signal_wait() { 2274 return check_pending_signals(true); 2275 } 2276 2277 //////////////////////////////////////////////////////////////////////////////// 2278 // Virtual Memory 2279 2280 int os::vm_page_size() { 2281 // Seems redundant as all get out 2282 assert(os::Linux::page_size() != -1, "must call os::init"); 2283 return os::Linux::page_size(); 2284 } 2285 2286 // Solaris allocates memory by pages. 2287 int os::vm_allocation_granularity() { 2288 assert(os::Linux::page_size() != -1, "must call os::init"); 2289 return os::Linux::page_size(); 2290 } 2291 2292 // Rationale behind this function: 2293 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2294 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2295 // samples for JITted code. Here we create private executable mapping over the code cache 2296 // and then we can use standard (well, almost, as mapping can change) way to provide 2297 // info for the reporting script by storing timestamp and location of symbol 2298 void linux_wrap_code(char* base, size_t size) { 2299 static volatile jint cnt = 0; 2300 2301 if (!UseOprofile) { 2302 return; 2303 } 2304 2305 char buf[40]; 2306 int num = Atomic::add(1, &cnt); 2307 2308 sprintf(buf, "/tmp/hs-vm-%d-%d", os::current_process_id(), num); 2309 unlink(buf); 2310 2311 int fd = open(buf, O_CREAT | O_RDWR, S_IRWXU); 2312 2313 if (fd != -1) { 2314 off_t rv = lseek(fd, size-2, SEEK_SET); 2315 if (rv != (off_t)-1) { 2316 if (write(fd, "", 1) == 1) { 2317 mmap(base, size, 2318 PROT_READ|PROT_WRITE|PROT_EXEC, 2319 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2320 } 2321 } 2322 close(fd); 2323 unlink(buf); 2324 } 2325 } 2326 2327 // NOTE: Linux kernel does not really reserve the pages for us. 2328 // All it does is to check if there are enough free pages 2329 // left at the time of mmap(). This could be a potential 2330 // problem. 2331 bool os::commit_memory(char* addr, size_t size, bool exec) { 2332 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2333 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2334 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2335 return res != (uintptr_t) MAP_FAILED; 2336 } 2337 2338 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint, 2339 bool exec) { 2340 return commit_memory(addr, size, exec); 2341 } 2342 2343 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { } 2344 2345 void os::free_memory(char *addr, size_t bytes) { 2346 ::mmap(addr, bytes, PROT_READ | PROT_WRITE, 2347 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2348 } 2349 2350 void os::numa_make_global(char *addr, size_t bytes) { 2351 Linux::numa_interleave_memory(addr, bytes); 2352 } 2353 2354 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2355 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2356 } 2357 2358 bool os::numa_topology_changed() { return false; } 2359 2360 size_t os::numa_get_groups_num() { 2361 int max_node = Linux::numa_max_node(); 2362 return max_node > 0 ? max_node + 1 : 1; 2363 } 2364 2365 int os::numa_get_group_id() { 2366 int cpu_id = Linux::sched_getcpu(); 2367 if (cpu_id != -1) { 2368 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2369 if (lgrp_id != -1) { 2370 return lgrp_id; 2371 } 2372 } 2373 return 0; 2374 } 2375 2376 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2377 for (size_t i = 0; i < size; i++) { 2378 ids[i] = i; 2379 } 2380 return size; 2381 } 2382 2383 bool os::get_page_info(char *start, page_info* info) { 2384 return false; 2385 } 2386 2387 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) { 2388 return end; 2389 } 2390 2391 extern "C" void numa_warn(int number, char *where, ...) { } 2392 extern "C" void numa_error(char *where) { } 2393 2394 2395 // If we are running with libnuma version > 2, then we should 2396 // be trying to use symbols with versions 1.1 2397 // If we are running with earlier version, which did not have symbol versions, 2398 // we should use the base version. 2399 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2400 void *f = dlvsym(handle, name, "libnuma_1.1"); 2401 if (f == NULL) { 2402 f = dlsym(handle, name); 2403 } 2404 return f; 2405 } 2406 2407 bool os::Linux::libnuma_init() { 2408 // sched_getcpu() should be in libc. 2409 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2410 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2411 2412 if (sched_getcpu() != -1) { // Does it work? 2413 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2414 if (handle != NULL) { 2415 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2416 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2417 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2418 libnuma_dlsym(handle, "numa_max_node"))); 2419 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2420 libnuma_dlsym(handle, "numa_available"))); 2421 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2422 libnuma_dlsym(handle, "numa_tonode_memory"))); 2423 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2424 libnuma_dlsym(handle, "numa_interleave_memory"))); 2425 2426 2427 if (numa_available() != -1) { 2428 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2429 // Create a cpu -> node mapping 2430 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true); 2431 rebuild_cpu_to_node_map(); 2432 return true; 2433 } 2434 } 2435 } 2436 return false; 2437 } 2438 2439 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2440 // The table is later used in get_node_by_cpu(). 2441 void os::Linux::rebuild_cpu_to_node_map() { 2442 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2443 // in libnuma (possible values are starting from 16, 2444 // and continuing up with every other power of 2, but less 2445 // than the maximum number of CPUs supported by kernel), and 2446 // is a subject to change (in libnuma version 2 the requirements 2447 // are more reasonable) we'll just hardcode the number they use 2448 // in the library. 2449 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2450 2451 size_t cpu_num = os::active_processor_count(); 2452 size_t cpu_map_size = NCPUS / BitsPerCLong; 2453 size_t cpu_map_valid_size = 2454 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2455 2456 cpu_to_node()->clear(); 2457 cpu_to_node()->at_grow(cpu_num - 1); 2458 size_t node_num = numa_get_groups_num(); 2459 2460 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size); 2461 for (size_t i = 0; i < node_num; i++) { 2462 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2463 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2464 if (cpu_map[j] != 0) { 2465 for (size_t k = 0; k < BitsPerCLong; k++) { 2466 if (cpu_map[j] & (1UL << k)) { 2467 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2468 } 2469 } 2470 } 2471 } 2472 } 2473 } 2474 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2475 } 2476 2477 int os::Linux::get_node_by_cpu(int cpu_id) { 2478 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2479 return cpu_to_node()->at(cpu_id); 2480 } 2481 return -1; 2482 } 2483 2484 GrowableArray<int>* os::Linux::_cpu_to_node; 2485 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2486 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2487 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2488 os::Linux::numa_available_func_t os::Linux::_numa_available; 2489 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2490 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2491 unsigned long* os::Linux::_numa_all_nodes; 2492 2493 bool os::uncommit_memory(char* addr, size_t size) { 2494 return ::mmap(addr, size, PROT_NONE, 2495 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0) 2496 != MAP_FAILED; 2497 } 2498 2499 static bool 2500 get_stack_bounds(uintptr_t *bottom, uintptr_t *top) 2501 { 2502 using namespace std; 2503 2504 ostringstream oss; 2505 oss << "/proc/" << syscall(SYS_gettid) << "/maps"; 2506 ifstream cin(oss.str().c_str()); 2507 while (!cin.eof()) 2508 { 2509 string str; 2510 getline(cin,str); 2511 const string stack_str = "[stack]"; 2512 if (str.length() > stack_str.length() 2513 && (str.compare(str.length() - stack_str.length(), 2514 stack_str.length(), stack_str) 2515 == 0)) 2516 { 2517 istringstream iss(str); 2518 iss.flags(ios::hex); 2519 iss >> *bottom; 2520 char c; 2521 iss >> c; 2522 iss >> *top; 2523 uintptr_t sp = (intptr_t)__builtin_frame_address(0); 2524 if (sp >= *bottom && sp <= *top) 2525 return true; 2526 } 2527 } 2528 2529 return false; 2530 } 2531 2532 bool os::create_stack_guard_pages(char* addr, size_t size) { 2533 uintptr_t stack_extent, stack_base; 2534 if (get_stack_bounds(&stack_extent, &stack_base)) { 2535 if (stack_extent < (uintptr_t)addr) 2536 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent); 2537 } 2538 2539 return os::commit_memory(addr, size); 2540 } 2541 2542 bool os::remove_stack_guard_pages(char* addr, size_t size) { 2543 return ::munmap(addr, size) == 0; 2544 } 2545 2546 static address _highest_vm_reserved_address = NULL; 2547 2548 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 2549 // at 'requested_addr'. If there are existing memory mappings at the same 2550 // location, however, they will be overwritten. If 'fixed' is false, 2551 // 'requested_addr' is only treated as a hint, the return value may or 2552 // may not start from the requested address. Unlike Linux mmap(), this 2553 // function returns NULL to indicate failure. 2554 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 2555 char * addr; 2556 int flags; 2557 2558 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 2559 if (fixed) { 2560 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 2561 flags |= MAP_FIXED; 2562 } 2563 2564 // Map uncommitted pages PROT_READ and PROT_WRITE, change access 2565 // to PROT_EXEC if executable when we commit the page. 2566 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE, 2567 flags, -1, 0); 2568 2569 if (addr != MAP_FAILED) { 2570 // anon_mmap() should only get called during VM initialization, 2571 // don't need lock (actually we can skip locking even it can be called 2572 // from multiple threads, because _highest_vm_reserved_address is just a 2573 // hint about the upper limit of non-stack memory regions.) 2574 if ((address)addr + bytes > _highest_vm_reserved_address) { 2575 _highest_vm_reserved_address = (address)addr + bytes; 2576 } 2577 } 2578 2579 return addr == MAP_FAILED ? NULL : addr; 2580 } 2581 2582 // Don't update _highest_vm_reserved_address, because there might be memory 2583 // regions above addr + size. If so, releasing a memory region only creates 2584 // a hole in the address space, it doesn't help prevent heap-stack collision. 2585 // 2586 static int anon_munmap(char * addr, size_t size) { 2587 return ::munmap(addr, size) == 0; 2588 } 2589 2590 char* os::reserve_memory(size_t bytes, char* requested_addr, 2591 size_t alignment_hint) { 2592 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 2593 } 2594 2595 bool os::release_memory(char* addr, size_t size) { 2596 return anon_munmap(addr, size); 2597 } 2598 2599 static address highest_vm_reserved_address() { 2600 return _highest_vm_reserved_address; 2601 } 2602 2603 static bool linux_mprotect(char* addr, size_t size, int prot) { 2604 // Linux wants the mprotect address argument to be page aligned. 2605 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 2606 2607 // According to SUSv3, mprotect() should only be used with mappings 2608 // established by mmap(), and mmap() always maps whole pages. Unaligned 2609 // 'addr' likely indicates problem in the VM (e.g. trying to change 2610 // protection of malloc'ed or statically allocated memory). Check the 2611 // caller if you hit this assert. 2612 assert(addr == bottom, "sanity check"); 2613 2614 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 2615 return ::mprotect(bottom, size, prot) == 0; 2616 } 2617 2618 // Set protections specified 2619 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 2620 bool is_committed) { 2621 unsigned int p = 0; 2622 switch (prot) { 2623 case MEM_PROT_NONE: p = PROT_NONE; break; 2624 case MEM_PROT_READ: p = PROT_READ; break; 2625 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 2626 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 2627 default: 2628 ShouldNotReachHere(); 2629 } 2630 // is_committed is unused. 2631 return linux_mprotect(addr, bytes, p); 2632 } 2633 2634 bool os::guard_memory(char* addr, size_t size) { 2635 return linux_mprotect(addr, size, PROT_NONE); 2636 } 2637 2638 bool os::unguard_memory(char* addr, size_t size) { 2639 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 2640 } 2641 2642 // Large page support 2643 2644 static size_t _large_page_size = 0; 2645 2646 bool os::large_page_init() { 2647 if (!UseLargePages) return false; 2648 2649 if (LargePageSizeInBytes) { 2650 _large_page_size = LargePageSizeInBytes; 2651 } else { 2652 // large_page_size on Linux is used to round up heap size. x86 uses either 2653 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 2654 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 2655 // page as large as 256M. 2656 // 2657 // Here we try to figure out page size by parsing /proc/meminfo and looking 2658 // for a line with the following format: 2659 // Hugepagesize: 2048 kB 2660 // 2661 // If we can't determine the value (e.g. /proc is not mounted, or the text 2662 // format has been changed), we'll use the largest page size supported by 2663 // the processor. 2664 2665 #ifndef ZERO 2666 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M); 2667 #endif // ZERO 2668 2669 FILE *fp = fopen("/proc/meminfo", "r"); 2670 if (fp) { 2671 while (!feof(fp)) { 2672 int x = 0; 2673 char buf[16]; 2674 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 2675 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 2676 _large_page_size = x * K; 2677 break; 2678 } 2679 } else { 2680 // skip to next line 2681 for (;;) { 2682 int ch = fgetc(fp); 2683 if (ch == EOF || ch == (int)'\n') break; 2684 } 2685 } 2686 } 2687 fclose(fp); 2688 } 2689 } 2690 2691 const size_t default_page_size = (size_t)Linux::page_size(); 2692 if (_large_page_size > default_page_size) { 2693 _page_sizes[0] = _large_page_size; 2694 _page_sizes[1] = default_page_size; 2695 _page_sizes[2] = 0; 2696 } 2697 2698 // Large page support is available on 2.6 or newer kernel, some vendors 2699 // (e.g. Redhat) have backported it to their 2.4 based distributions. 2700 // We optimistically assume the support is available. If later it turns out 2701 // not true, VM will automatically switch to use regular page size. 2702 return true; 2703 } 2704 2705 #ifndef SHM_HUGETLB 2706 #define SHM_HUGETLB 04000 2707 #endif 2708 2709 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) { 2710 // "exec" is passed in but not used. Creating the shared image for 2711 // the code cache doesn't have an SHM_X executable permission to check. 2712 assert(UseLargePages, "only for large pages"); 2713 2714 key_t key = IPC_PRIVATE; 2715 char *addr; 2716 2717 bool warn_on_failure = UseLargePages && 2718 (!FLAG_IS_DEFAULT(UseLargePages) || 2719 !FLAG_IS_DEFAULT(LargePageSizeInBytes) 2720 ); 2721 char msg[128]; 2722 2723 // Create a large shared memory region to attach to based on size. 2724 // Currently, size is the total size of the heap 2725 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 2726 if (shmid == -1) { 2727 // Possible reasons for shmget failure: 2728 // 1. shmmax is too small for Java heap. 2729 // > check shmmax value: cat /proc/sys/kernel/shmmax 2730 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 2731 // 2. not enough large page memory. 2732 // > check available large pages: cat /proc/meminfo 2733 // > increase amount of large pages: 2734 // echo new_value > /proc/sys/vm/nr_hugepages 2735 // Note 1: different Linux may use different name for this property, 2736 // e.g. on Redhat AS-3 it is "hugetlb_pool". 2737 // Note 2: it's possible there's enough physical memory available but 2738 // they are so fragmented after a long run that they can't 2739 // coalesce into large pages. Try to reserve large pages when 2740 // the system is still "fresh". 2741 if (warn_on_failure) { 2742 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 2743 warning(msg); 2744 } 2745 return NULL; 2746 } 2747 2748 // attach to the region 2749 addr = (char*)shmat(shmid, NULL, 0); 2750 int err = errno; 2751 2752 // Remove shmid. If shmat() is successful, the actual shared memory segment 2753 // will be deleted when it's detached by shmdt() or when the process 2754 // terminates. If shmat() is not successful this will remove the shared 2755 // segment immediately. 2756 shmctl(shmid, IPC_RMID, NULL); 2757 2758 if ((intptr_t)addr == -1) { 2759 if (warn_on_failure) { 2760 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 2761 warning(msg); 2762 } 2763 return NULL; 2764 } 2765 2766 return addr; 2767 } 2768 2769 bool os::release_memory_special(char* base, size_t bytes) { 2770 // detaching the SHM segment will also delete it, see reserve_memory_special() 2771 int rslt = shmdt(base); 2772 return rslt == 0; 2773 } 2774 2775 size_t os::large_page_size() { 2776 return _large_page_size; 2777 } 2778 2779 // Linux does not support anonymous mmap with large page memory. The only way 2780 // to reserve large page memory without file backing is through SysV shared 2781 // memory API. The entire memory region is committed and pinned upfront. 2782 // Hopefully this will change in the future... 2783 bool os::can_commit_large_page_memory() { 2784 return false; 2785 } 2786 2787 bool os::can_execute_large_page_memory() { 2788 return false; 2789 } 2790 2791 // Reserve memory at an arbitrary address, only if that area is 2792 // available (and not reserved for something else). 2793 2794 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 2795 const int max_tries = 10; 2796 char* base[max_tries]; 2797 size_t size[max_tries]; 2798 const size_t gap = 0x000000; 2799 2800 // Assert only that the size is a multiple of the page size, since 2801 // that's all that mmap requires, and since that's all we really know 2802 // about at this low abstraction level. If we need higher alignment, 2803 // we can either pass an alignment to this method or verify alignment 2804 // in one of the methods further up the call chain. See bug 5044738. 2805 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 2806 2807 // Repeatedly allocate blocks until the block is allocated at the 2808 // right spot. Give up after max_tries. Note that reserve_memory() will 2809 // automatically update _highest_vm_reserved_address if the call is 2810 // successful. The variable tracks the highest memory address every reserved 2811 // by JVM. It is used to detect heap-stack collision if running with 2812 // fixed-stack LinuxThreads. Because here we may attempt to reserve more 2813 // space than needed, it could confuse the collision detecting code. To 2814 // solve the problem, save current _highest_vm_reserved_address and 2815 // calculate the correct value before return. 2816 address old_highest = _highest_vm_reserved_address; 2817 2818 // Linux mmap allows caller to pass an address as hint; give it a try first, 2819 // if kernel honors the hint then we can return immediately. 2820 char * addr = anon_mmap(requested_addr, bytes, false); 2821 if (addr == requested_addr) { 2822 return requested_addr; 2823 } 2824 2825 if (addr != NULL) { 2826 // mmap() is successful but it fails to reserve at the requested address 2827 anon_munmap(addr, bytes); 2828 } 2829 2830 int i; 2831 for (i = 0; i < max_tries; ++i) { 2832 base[i] = reserve_memory(bytes); 2833 2834 if (base[i] != NULL) { 2835 // Is this the block we wanted? 2836 if (base[i] == requested_addr) { 2837 size[i] = bytes; 2838 break; 2839 } 2840 2841 // Does this overlap the block we wanted? Give back the overlapped 2842 // parts and try again. 2843 2844 size_t top_overlap = requested_addr + (bytes + gap) - base[i]; 2845 if (top_overlap >= 0 && top_overlap < bytes) { 2846 unmap_memory(base[i], top_overlap); 2847 base[i] += top_overlap; 2848 size[i] = bytes - top_overlap; 2849 } else { 2850 size_t bottom_overlap = base[i] + bytes - requested_addr; 2851 if (bottom_overlap >= 0 && bottom_overlap < bytes) { 2852 unmap_memory(requested_addr, bottom_overlap); 2853 size[i] = bytes - bottom_overlap; 2854 } else { 2855 size[i] = bytes; 2856 } 2857 } 2858 } 2859 } 2860 2861 // Give back the unused reserved pieces. 2862 2863 for (int j = 0; j < i; ++j) { 2864 if (base[j] != NULL) { 2865 unmap_memory(base[j], size[j]); 2866 } 2867 } 2868 2869 if (i < max_tries) { 2870 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes); 2871 return requested_addr; 2872 } else { 2873 _highest_vm_reserved_address = old_highest; 2874 return NULL; 2875 } 2876 } 2877 2878 size_t os::read(int fd, void *buf, unsigned int nBytes) { 2879 return ::read(fd, buf, nBytes); 2880 } 2881 2882 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation. 2883 // Solaris uses poll(), linux uses park(). 2884 // Poll() is likely a better choice, assuming that Thread.interrupt() 2885 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with 2886 // SIGSEGV, see 4355769. 2887 2888 const int NANOSECS_PER_MILLISECS = 1000000; 2889 2890 int os::sleep(Thread* thread, jlong millis, bool interruptible) { 2891 assert(thread == Thread::current(), "thread consistency check"); 2892 2893 ParkEvent * const slp = thread->_SleepEvent ; 2894 slp->reset() ; 2895 OrderAccess::fence() ; 2896 2897 if (interruptible) { 2898 jlong prevtime = javaTimeNanos(); 2899 2900 for (;;) { 2901 if (os::is_interrupted(thread, true)) { 2902 return OS_INTRPT; 2903 } 2904 2905 jlong newtime = javaTimeNanos(); 2906 2907 if (newtime - prevtime < 0) { 2908 // time moving backwards, should only happen if no monotonic clock 2909 // not a guarantee() because JVM should not abort on kernel/glibc bugs 2910 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 2911 } else { 2912 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS; 2913 } 2914 2915 if(millis <= 0) { 2916 return OS_OK; 2917 } 2918 2919 prevtime = newtime; 2920 2921 { 2922 assert(thread->is_Java_thread(), "sanity check"); 2923 JavaThread *jt = (JavaThread *) thread; 2924 ThreadBlockInVM tbivm(jt); 2925 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 2926 2927 jt->set_suspend_equivalent(); 2928 // cleared by handle_special_suspend_equivalent_condition() or 2929 // java_suspend_self() via check_and_wait_while_suspended() 2930 2931 slp->park(millis); 2932 2933 // were we externally suspended while we were waiting? 2934 jt->check_and_wait_while_suspended(); 2935 } 2936 } 2937 } else { 2938 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 2939 jlong prevtime = javaTimeNanos(); 2940 2941 for (;;) { 2942 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 2943 // the 1st iteration ... 2944 jlong newtime = javaTimeNanos(); 2945 2946 if (newtime - prevtime < 0) { 2947 // time moving backwards, should only happen if no monotonic clock 2948 // not a guarantee() because JVM should not abort on kernel/glibc bugs 2949 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 2950 } else { 2951 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS; 2952 } 2953 2954 if(millis <= 0) break ; 2955 2956 prevtime = newtime; 2957 slp->park(millis); 2958 } 2959 return OS_OK ; 2960 } 2961 } 2962 2963 int os::naked_sleep() { 2964 // %% make the sleep time an integer flag. for now use 1 millisec. 2965 return os::sleep(Thread::current(), 1, false); 2966 } 2967 2968 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 2969 void os::infinite_sleep() { 2970 while (true) { // sleep forever ... 2971 ::sleep(100); // ... 100 seconds at a time 2972 } 2973 } 2974 2975 // Used to convert frequent JVM_Yield() to nops 2976 bool os::dont_yield() { 2977 return DontYieldALot; 2978 } 2979 2980 void os::yield() { 2981 sched_yield(); 2982 } 2983 2984 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;} 2985 2986 void os::yield_all(int attempts) { 2987 // Yields to all threads, including threads with lower priorities 2988 // Threads on Linux are all with same priority. The Solaris style 2989 // os::yield_all() with nanosleep(1ms) is not necessary. 2990 sched_yield(); 2991 } 2992 2993 // Called from the tight loops to possibly influence time-sharing heuristics 2994 void os::loop_breaker(int attempts) { 2995 os::yield_all(attempts); 2996 } 2997 2998 //////////////////////////////////////////////////////////////////////////////// 2999 // thread priority support 3000 3001 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3002 // only supports dynamic priority, static priority must be zero. For real-time 3003 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3004 // However, for large multi-threaded applications, SCHED_RR is not only slower 3005 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3006 // of 5 runs - Sep 2005). 3007 // 3008 // The following code actually changes the niceness of kernel-thread/LWP. It 3009 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3010 // not the entire user process, and user level threads are 1:1 mapped to kernel 3011 // threads. It has always been the case, but could change in the future. For 3012 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3013 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3014 3015 int os::java_to_os_priority[MaxPriority + 1] = { 3016 19, // 0 Entry should never be used 3017 3018 4, // 1 MinPriority 3019 3, // 2 3020 2, // 3 3021 3022 1, // 4 3023 0, // 5 NormPriority 3024 -1, // 6 3025 3026 -2, // 7 3027 -3, // 8 3028 -4, // 9 NearMaxPriority 3029 3030 -5 // 10 MaxPriority 3031 }; 3032 3033 static int prio_init() { 3034 if (ThreadPriorityPolicy == 1) { 3035 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3036 // if effective uid is not root. Perhaps, a more elegant way of doing 3037 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3038 if (geteuid() != 0) { 3039 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3040 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3041 } 3042 ThreadPriorityPolicy = 0; 3043 } 3044 } 3045 return 0; 3046 } 3047 3048 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3049 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK; 3050 3051 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3052 return (ret == 0) ? OS_OK : OS_ERR; 3053 } 3054 3055 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) { 3056 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) { 3057 *priority_ptr = java_to_os_priority[NormPriority]; 3058 return OS_OK; 3059 } 3060 3061 errno = 0; 3062 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3063 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3064 } 3065 3066 // Hint to the underlying OS that a task switch would not be good. 3067 // Void return because it's a hint and can fail. 3068 void os::hint_no_preempt() {} 3069 3070 //////////////////////////////////////////////////////////////////////////////// 3071 // suspend/resume support 3072 3073 // the low-level signal-based suspend/resume support is a remnant from the 3074 // old VM-suspension that used to be for java-suspension, safepoints etc, 3075 // within hotspot. Now there is a single use-case for this: 3076 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3077 // that runs in the watcher thread. 3078 // The remaining code is greatly simplified from the more general suspension 3079 // code that used to be used. 3080 // 3081 // The protocol is quite simple: 3082 // - suspend: 3083 // - sends a signal to the target thread 3084 // - polls the suspend state of the osthread using a yield loop 3085 // - target thread signal handler (SR_handler) sets suspend state 3086 // and blocks in sigsuspend until continued 3087 // - resume: 3088 // - sets target osthread state to continue 3089 // - sends signal to end the sigsuspend loop in the SR_handler 3090 // 3091 // Note that the SR_lock plays no role in this suspend/resume protocol. 3092 // 3093 3094 static void resume_clear_context(OSThread *osthread) { 3095 osthread->set_ucontext(NULL); 3096 osthread->set_siginfo(NULL); 3097 3098 // notify the suspend action is completed, we have now resumed 3099 osthread->sr.clear_suspended(); 3100 } 3101 3102 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) { 3103 osthread->set_ucontext(context); 3104 osthread->set_siginfo(siginfo); 3105 } 3106 3107 // 3108 // Handler function invoked when a thread's execution is suspended or 3109 // resumed. We have to be careful that only async-safe functions are 3110 // called here (Note: most pthread functions are not async safe and 3111 // should be avoided.) 3112 // 3113 // Note: sigwait() is a more natural fit than sigsuspend() from an 3114 // interface point of view, but sigwait() prevents the signal hander 3115 // from being run. libpthread would get very confused by not having 3116 // its signal handlers run and prevents sigwait()'s use with the 3117 // mutex granting granting signal. 3118 // 3119 // Currently only ever called on the VMThread 3120 // 3121 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3122 // Save and restore errno to avoid confusing native code with EINTR 3123 // after sigsuspend. 3124 int old_errno = errno; 3125 3126 Thread* thread = Thread::current(); 3127 OSThread* osthread = thread->osthread(); 3128 assert(thread->is_VM_thread(), "Must be VMThread"); 3129 // read current suspend action 3130 int action = osthread->sr.suspend_action(); 3131 if (action == SR_SUSPEND) { 3132 suspend_save_context(osthread, siginfo, context); 3133 3134 // Notify the suspend action is about to be completed. do_suspend() 3135 // waits until SR_SUSPENDED is set and then returns. We will wait 3136 // here for a resume signal and that completes the suspend-other 3137 // action. do_suspend/do_resume is always called as a pair from 3138 // the same thread - so there are no races 3139 3140 // notify the caller 3141 osthread->sr.set_suspended(); 3142 3143 sigset_t suspend_set; // signals for sigsuspend() 3144 3145 // get current set of blocked signals and unblock resume signal 3146 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3147 sigdelset(&suspend_set, SR_signum); 3148 3149 // wait here until we are resumed 3150 do { 3151 sigsuspend(&suspend_set); 3152 // ignore all returns until we get a resume signal 3153 } while (osthread->sr.suspend_action() != SR_CONTINUE); 3154 3155 resume_clear_context(osthread); 3156 3157 } else { 3158 assert(action == SR_CONTINUE, "unexpected sr action"); 3159 // nothing special to do - just leave the handler 3160 } 3161 3162 errno = old_errno; 3163 } 3164 3165 3166 static int SR_initialize() { 3167 struct sigaction act; 3168 char *s; 3169 /* Get signal number to use for suspend/resume */ 3170 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3171 int sig = ::strtol(s, 0, 10); 3172 if (sig > 0 || sig < _NSIG) { 3173 SR_signum = sig; 3174 } 3175 } 3176 3177 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 3178 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 3179 3180 sigemptyset(&SR_sigset); 3181 sigaddset(&SR_sigset, SR_signum); 3182 3183 /* Set up signal handler for suspend/resume */ 3184 act.sa_flags = SA_RESTART|SA_SIGINFO; 3185 act.sa_handler = (void (*)(int)) SR_handler; 3186 3187 // SR_signum is blocked by default. 3188 // 4528190 - We also need to block pthread restart signal (32 on all 3189 // supported Linux platforms). Note that LinuxThreads need to block 3190 // this signal for all threads to work properly. So we don't have 3191 // to use hard-coded signal number when setting up the mask. 3192 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 3193 3194 if (sigaction(SR_signum, &act, 0) == -1) { 3195 return -1; 3196 } 3197 3198 // Save signal flag 3199 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 3200 return 0; 3201 } 3202 3203 static int SR_finalize() { 3204 return 0; 3205 } 3206 3207 3208 // returns true on success and false on error - really an error is fatal 3209 // but this seems the normal response to library errors 3210 static bool do_suspend(OSThread* osthread) { 3211 // mark as suspended and send signal 3212 osthread->sr.set_suspend_action(SR_SUSPEND); 3213 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3214 assert_status(status == 0, status, "pthread_kill"); 3215 3216 // check status and wait until notified of suspension 3217 if (status == 0) { 3218 for (int i = 0; !osthread->sr.is_suspended(); i++) { 3219 os::yield_all(i); 3220 } 3221 osthread->sr.set_suspend_action(SR_NONE); 3222 return true; 3223 } 3224 else { 3225 osthread->sr.set_suspend_action(SR_NONE); 3226 return false; 3227 } 3228 } 3229 3230 static void do_resume(OSThread* osthread) { 3231 assert(osthread->sr.is_suspended(), "thread should be suspended"); 3232 osthread->sr.set_suspend_action(SR_CONTINUE); 3233 3234 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3235 assert_status(status == 0, status, "pthread_kill"); 3236 // check status and wait unit notified of resumption 3237 if (status == 0) { 3238 for (int i = 0; osthread->sr.is_suspended(); i++) { 3239 os::yield_all(i); 3240 } 3241 } 3242 osthread->sr.set_suspend_action(SR_NONE); 3243 } 3244 3245 //////////////////////////////////////////////////////////////////////////////// 3246 // interrupt support 3247 3248 void os::interrupt(Thread* thread) { 3249 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3250 "possibility of dangling Thread pointer"); 3251 3252 OSThread* osthread = thread->osthread(); 3253 3254 if (!osthread->interrupted()) { 3255 osthread->set_interrupted(true); 3256 // More than one thread can get here with the same value of osthread, 3257 // resulting in multiple notifications. We do, however, want the store 3258 // to interrupted() to be visible to other threads before we execute unpark(). 3259 OrderAccess::fence(); 3260 ParkEvent * const slp = thread->_SleepEvent ; 3261 if (slp != NULL) slp->unpark() ; 3262 } 3263 3264 // For JSR166. Unpark even if interrupt status already was set 3265 if (thread->is_Java_thread()) 3266 ((JavaThread*)thread)->parker()->unpark(); 3267 3268 ParkEvent * ev = thread->_ParkEvent ; 3269 if (ev != NULL) ev->unpark() ; 3270 3271 } 3272 3273 bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 3274 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3275 "possibility of dangling Thread pointer"); 3276 3277 OSThread* osthread = thread->osthread(); 3278 3279 bool interrupted = osthread->interrupted(); 3280 3281 if (interrupted && clear_interrupted) { 3282 osthread->set_interrupted(false); 3283 // consider thread->_SleepEvent->reset() ... optional optimization 3284 } 3285 3286 return interrupted; 3287 } 3288 3289 /////////////////////////////////////////////////////////////////////////////////// 3290 // signal handling (except suspend/resume) 3291 3292 // This routine may be used by user applications as a "hook" to catch signals. 3293 // The user-defined signal handler must pass unrecognized signals to this 3294 // routine, and if it returns true (non-zero), then the signal handler must 3295 // return immediately. If the flag "abort_if_unrecognized" is true, then this 3296 // routine will never retun false (zero), but instead will execute a VM panic 3297 // routine kill the process. 3298 // 3299 // If this routine returns false, it is OK to call it again. This allows 3300 // the user-defined signal handler to perform checks either before or after 3301 // the VM performs its own checks. Naturally, the user code would be making 3302 // a serious error if it tried to handle an exception (such as a null check 3303 // or breakpoint) that the VM was generating for its own correct operation. 3304 // 3305 // This routine may recognize any of the following kinds of signals: 3306 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 3307 // It should be consulted by handlers for any of those signals. 3308 // 3309 // The caller of this routine must pass in the three arguments supplied 3310 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 3311 // field of the structure passed to sigaction(). This routine assumes that 3312 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 3313 // 3314 // Note that the VM will print warnings if it detects conflicting signal 3315 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 3316 // 3317 extern "C" int 3318 JVM_handle_linux_signal(int signo, siginfo_t* siginfo, 3319 void* ucontext, int abort_if_unrecognized); 3320 3321 void signalHandler(int sig, siginfo_t* info, void* uc) { 3322 assert(info != NULL && uc != NULL, "it must be old kernel"); 3323 JVM_handle_linux_signal(sig, info, uc, true); 3324 } 3325 3326 3327 // This boolean allows users to forward their own non-matching signals 3328 // to JVM_handle_linux_signal, harmlessly. 3329 bool os::Linux::signal_handlers_are_installed = false; 3330 3331 // For signal-chaining 3332 struct sigaction os::Linux::sigact[MAXSIGNUM]; 3333 unsigned int os::Linux::sigs = 0; 3334 bool os::Linux::libjsig_is_loaded = false; 3335 typedef struct sigaction *(*get_signal_t)(int); 3336 get_signal_t os::Linux::get_signal_action = NULL; 3337 3338 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 3339 struct sigaction *actp = NULL; 3340 3341 if (libjsig_is_loaded) { 3342 // Retrieve the old signal handler from libjsig 3343 actp = (*get_signal_action)(sig); 3344 } 3345 if (actp == NULL) { 3346 // Retrieve the preinstalled signal handler from jvm 3347 actp = get_preinstalled_handler(sig); 3348 } 3349 3350 return actp; 3351 } 3352 3353 static bool call_chained_handler(struct sigaction *actp, int sig, 3354 siginfo_t *siginfo, void *context) { 3355 // Call the old signal handler 3356 if (actp->sa_handler == SIG_DFL) { 3357 // It's more reasonable to let jvm treat it as an unexpected exception 3358 // instead of taking the default action. 3359 return false; 3360 } else if (actp->sa_handler != SIG_IGN) { 3361 if ((actp->sa_flags & SA_NODEFER) == 0) { 3362 // automaticlly block the signal 3363 sigaddset(&(actp->sa_mask), sig); 3364 } 3365 3366 sa_handler_t hand; 3367 sa_sigaction_t sa; 3368 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 3369 // retrieve the chained handler 3370 if (siginfo_flag_set) { 3371 sa = actp->sa_sigaction; 3372 } else { 3373 hand = actp->sa_handler; 3374 } 3375 3376 if ((actp->sa_flags & SA_RESETHAND) != 0) { 3377 actp->sa_handler = SIG_DFL; 3378 } 3379 3380 // try to honor the signal mask 3381 sigset_t oset; 3382 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 3383 3384 // call into the chained handler 3385 if (siginfo_flag_set) { 3386 (*sa)(sig, siginfo, context); 3387 } else { 3388 (*hand)(sig); 3389 } 3390 3391 // restore the signal mask 3392 pthread_sigmask(SIG_SETMASK, &oset, 0); 3393 } 3394 // Tell jvm's signal handler the signal is taken care of. 3395 return true; 3396 } 3397 3398 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 3399 bool chained = false; 3400 // signal-chaining 3401 if (UseSignalChaining) { 3402 struct sigaction *actp = get_chained_signal_action(sig); 3403 if (actp != NULL) { 3404 chained = call_chained_handler(actp, sig, siginfo, context); 3405 } 3406 } 3407 return chained; 3408 } 3409 3410 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 3411 if ((( (unsigned int)1 << sig ) & sigs) != 0) { 3412 return &sigact[sig]; 3413 } 3414 return NULL; 3415 } 3416 3417 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 3418 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3419 sigact[sig] = oldAct; 3420 sigs |= (unsigned int)1 << sig; 3421 } 3422 3423 // for diagnostic 3424 int os::Linux::sigflags[MAXSIGNUM]; 3425 3426 int os::Linux::get_our_sigflags(int sig) { 3427 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3428 return sigflags[sig]; 3429 } 3430 3431 void os::Linux::set_our_sigflags(int sig, int flags) { 3432 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3433 sigflags[sig] = flags; 3434 } 3435 3436 void os::Linux::set_signal_handler(int sig, bool set_installed) { 3437 // Check for overwrite. 3438 struct sigaction oldAct; 3439 sigaction(sig, (struct sigaction*)NULL, &oldAct); 3440 3441 void* oldhand = oldAct.sa_sigaction 3442 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3443 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3444 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 3445 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 3446 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 3447 if (AllowUserSignalHandlers || !set_installed) { 3448 // Do not overwrite; user takes responsibility to forward to us. 3449 return; 3450 } else if (UseSignalChaining) { 3451 // save the old handler in jvm 3452 save_preinstalled_handler(sig, oldAct); 3453 // libjsig also interposes the sigaction() call below and saves the 3454 // old sigaction on it own. 3455 } else { 3456 fatal2("Encountered unexpected pre-existing sigaction handler %#lx for signal %d.", (long)oldhand, sig); 3457 } 3458 } 3459 3460 struct sigaction sigAct; 3461 sigfillset(&(sigAct.sa_mask)); 3462 sigAct.sa_handler = SIG_DFL; 3463 if (!set_installed) { 3464 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3465 } else { 3466 sigAct.sa_sigaction = signalHandler; 3467 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3468 } 3469 // Save flags, which are set by ours 3470 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3471 sigflags[sig] = sigAct.sa_flags; 3472 3473 int ret = sigaction(sig, &sigAct, &oldAct); 3474 assert(ret == 0, "check"); 3475 3476 void* oldhand2 = oldAct.sa_sigaction 3477 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3478 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3479 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 3480 } 3481 3482 // install signal handlers for signals that HotSpot needs to 3483 // handle in order to support Java-level exception handling. 3484 3485 void os::Linux::install_signal_handlers() { 3486 if (!signal_handlers_are_installed) { 3487 signal_handlers_are_installed = true; 3488 3489 // signal-chaining 3490 typedef void (*signal_setting_t)(); 3491 signal_setting_t begin_signal_setting = NULL; 3492 signal_setting_t end_signal_setting = NULL; 3493 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3494 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 3495 if (begin_signal_setting != NULL) { 3496 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3497 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 3498 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 3499 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 3500 libjsig_is_loaded = true; 3501 assert(UseSignalChaining, "should enable signal-chaining"); 3502 } 3503 if (libjsig_is_loaded) { 3504 // Tell libjsig jvm is setting signal handlers 3505 (*begin_signal_setting)(); 3506 } 3507 3508 set_signal_handler(SIGSEGV, true); 3509 set_signal_handler(SIGPIPE, true); 3510 set_signal_handler(SIGBUS, true); 3511 set_signal_handler(SIGILL, true); 3512 set_signal_handler(SIGFPE, true); 3513 set_signal_handler(SIGXFSZ, true); 3514 3515 if (libjsig_is_loaded) { 3516 // Tell libjsig jvm finishes setting signal handlers 3517 (*end_signal_setting)(); 3518 } 3519 3520 // We don't activate signal checker if libjsig is in place, we trust ourselves 3521 // and if UserSignalHandler is installed all bets are off 3522 if (CheckJNICalls) { 3523 if (libjsig_is_loaded) { 3524 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 3525 check_signals = false; 3526 } 3527 if (AllowUserSignalHandlers) { 3528 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 3529 check_signals = false; 3530 } 3531 } 3532 } 3533 } 3534 3535 // This is the fastest way to get thread cpu time on Linux. 3536 // Returns cpu time (user+sys) for any thread, not only for current. 3537 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 3538 // It might work on 2.6.10+ with a special kernel/glibc patch. 3539 // For reference, please, see IEEE Std 1003.1-2004: 3540 // http://www.unix.org/single_unix_specification 3541 3542 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 3543 struct timespec tp; 3544 int rc = os::Linux::clock_gettime(clockid, &tp); 3545 assert(rc == 0, "clock_gettime is expected to return 0 code"); 3546 3547 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec; 3548 } 3549 3550 ///// 3551 // glibc on Linux platform uses non-documented flag 3552 // to indicate, that some special sort of signal 3553 // trampoline is used. 3554 // We will never set this flag, and we should 3555 // ignore this flag in our diagnostic 3556 #ifdef SIGNIFICANT_SIGNAL_MASK 3557 #undef SIGNIFICANT_SIGNAL_MASK 3558 #endif 3559 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 3560 3561 static const char* get_signal_handler_name(address handler, 3562 char* buf, int buflen) { 3563 int offset; 3564 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 3565 if (found) { 3566 // skip directory names 3567 const char *p1, *p2; 3568 p1 = buf; 3569 size_t len = strlen(os::file_separator()); 3570 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 3571 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 3572 } else { 3573 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 3574 } 3575 return buf; 3576 } 3577 3578 static void print_signal_handler(outputStream* st, int sig, 3579 char* buf, size_t buflen) { 3580 struct sigaction sa; 3581 3582 sigaction(sig, NULL, &sa); 3583 3584 // See comment for SIGNIFICANT_SIGNAL_MASK define 3585 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3586 3587 st->print("%s: ", os::exception_name(sig, buf, buflen)); 3588 3589 address handler = (sa.sa_flags & SA_SIGINFO) 3590 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 3591 : CAST_FROM_FN_PTR(address, sa.sa_handler); 3592 3593 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 3594 st->print("SIG_DFL"); 3595 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 3596 st->print("SIG_IGN"); 3597 } else { 3598 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 3599 } 3600 3601 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask); 3602 3603 address rh = VMError::get_resetted_sighandler(sig); 3604 // May be, handler was resetted by VMError? 3605 if(rh != NULL) { 3606 handler = rh; 3607 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 3608 } 3609 3610 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags); 3611 3612 // Check: is it our handler? 3613 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 3614 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 3615 // It is our signal handler 3616 // check for flags, reset system-used one! 3617 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 3618 st->print( 3619 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 3620 os::Linux::get_our_sigflags(sig)); 3621 } 3622 } 3623 st->cr(); 3624 } 3625 3626 3627 #define DO_SIGNAL_CHECK(sig) \ 3628 if (!sigismember(&check_signal_done, sig)) \ 3629 os::Linux::check_signal_handler(sig) 3630 3631 // This method is a periodic task to check for misbehaving JNI applications 3632 // under CheckJNI, we can add any periodic checks here 3633 3634 void os::run_periodic_checks() { 3635 3636 if (check_signals == false) return; 3637 3638 // SEGV and BUS if overridden could potentially prevent 3639 // generation of hs*.log in the event of a crash, debugging 3640 // such a case can be very challenging, so we absolutely 3641 // check the following for a good measure: 3642 DO_SIGNAL_CHECK(SIGSEGV); 3643 DO_SIGNAL_CHECK(SIGILL); 3644 DO_SIGNAL_CHECK(SIGFPE); 3645 DO_SIGNAL_CHECK(SIGBUS); 3646 DO_SIGNAL_CHECK(SIGPIPE); 3647 DO_SIGNAL_CHECK(SIGXFSZ); 3648 3649 3650 // ReduceSignalUsage allows the user to override these handlers 3651 // see comments at the very top and jvm_solaris.h 3652 if (!ReduceSignalUsage) { 3653 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 3654 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 3655 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 3656 DO_SIGNAL_CHECK(BREAK_SIGNAL); 3657 } 3658 3659 DO_SIGNAL_CHECK(SR_signum); 3660 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 3661 } 3662 3663 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 3664 3665 static os_sigaction_t os_sigaction = NULL; 3666 3667 void os::Linux::check_signal_handler(int sig) { 3668 char buf[O_BUFLEN]; 3669 address jvmHandler = NULL; 3670 3671 3672 struct sigaction act; 3673 if (os_sigaction == NULL) { 3674 // only trust the default sigaction, in case it has been interposed 3675 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 3676 if (os_sigaction == NULL) return; 3677 } 3678 3679 os_sigaction(sig, (struct sigaction*)NULL, &act); 3680 3681 3682 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3683 3684 address thisHandler = (act.sa_flags & SA_SIGINFO) 3685 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 3686 : CAST_FROM_FN_PTR(address, act.sa_handler) ; 3687 3688 3689 switch(sig) { 3690 case SIGSEGV: 3691 case SIGBUS: 3692 case SIGFPE: 3693 case SIGPIPE: 3694 case SIGILL: 3695 case SIGXFSZ: 3696 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 3697 break; 3698 3699 case SHUTDOWN1_SIGNAL: 3700 case SHUTDOWN2_SIGNAL: 3701 case SHUTDOWN3_SIGNAL: 3702 case BREAK_SIGNAL: 3703 jvmHandler = (address)user_handler(); 3704 break; 3705 3706 case INTERRUPT_SIGNAL: 3707 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 3708 break; 3709 3710 default: 3711 if (sig == SR_signum) { 3712 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 3713 } else { 3714 return; 3715 } 3716 break; 3717 } 3718 3719 if (thisHandler != jvmHandler) { 3720 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 3721 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 3722 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 3723 // No need to check this sig any longer 3724 sigaddset(&check_signal_done, sig); 3725 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 3726 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 3727 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 3728 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 3729 // No need to check this sig any longer 3730 sigaddset(&check_signal_done, sig); 3731 } 3732 3733 // Dump all the signal 3734 if (sigismember(&check_signal_done, sig)) { 3735 print_signal_handlers(tty, buf, O_BUFLEN); 3736 } 3737 } 3738 3739 extern void report_error(char* file_name, int line_no, char* title, char* format, ...); 3740 3741 extern bool signal_name(int signo, char* buf, size_t len); 3742 3743 const char* os::exception_name(int exception_code, char* buf, size_t size) { 3744 if (0 < exception_code && exception_code <= SIGRTMAX) { 3745 // signal 3746 if (!signal_name(exception_code, buf, size)) { 3747 jio_snprintf(buf, size, "SIG%d", exception_code); 3748 } 3749 return buf; 3750 } else { 3751 return NULL; 3752 } 3753 } 3754 3755 // this is called _before_ the most of global arguments have been parsed 3756 void os::init(void) { 3757 char dummy; /* used to get a guess on initial stack address */ 3758 // first_hrtime = gethrtime(); 3759 3760 // With LinuxThreads the JavaMain thread pid (primordial thread) 3761 // is different than the pid of the java launcher thread. 3762 // So, on Linux, the launcher thread pid is passed to the VM 3763 // via the sun.java.launcher.pid property. 3764 // Use this property instead of getpid() if it was correctly passed. 3765 // See bug 6351349. 3766 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid(); 3767 3768 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid(); 3769 3770 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 3771 3772 init_random(1234567); 3773 3774 ThreadCritical::initialize(); 3775 3776 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 3777 if (Linux::page_size() == -1) { 3778 fatal1("os_linux.cpp: os::init: sysconf failed (%s)", strerror(errno)); 3779 } 3780 init_page_sizes((size_t) Linux::page_size()); 3781 3782 Linux::initialize_system_info(); 3783 3784 // main_thread points to the aboriginal thread 3785 Linux::_main_thread = pthread_self(); 3786 3787 Linux::clock_init(); 3788 initial_time_count = os::elapsed_counter(); 3789 pthread_mutex_init(&dl_mutex, NULL); 3790 } 3791 3792 // To install functions for atexit system call 3793 extern "C" { 3794 static void perfMemory_exit_helper() { 3795 perfMemory_exit(); 3796 } 3797 } 3798 3799 // this is called _after_ the global arguments have been parsed 3800 jint os::init_2(void) 3801 { 3802 Linux::fast_thread_clock_init(); 3803 3804 // Allocate a single page and mark it as readable for safepoint polling 3805 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 3806 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" ); 3807 3808 os::set_polling_page( polling_page ); 3809 3810 #ifndef PRODUCT 3811 if(Verbose && PrintMiscellaneous) 3812 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page); 3813 #endif 3814 3815 if (!UseMembar) { 3816 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 3817 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page"); 3818 os::set_memory_serialize_page( mem_serialize_page ); 3819 3820 #ifndef PRODUCT 3821 if(Verbose && PrintMiscellaneous) 3822 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page); 3823 #endif 3824 } 3825 3826 FLAG_SET_DEFAULT(UseLargePages, os::large_page_init()); 3827 3828 // initialize suspend/resume support - must do this before signal_sets_init() 3829 if (SR_initialize() != 0) { 3830 perror("SR_initialize failed"); 3831 return JNI_ERR; 3832 } 3833 3834 Linux::signal_sets_init(); 3835 Linux::install_signal_handlers(); 3836 3837 size_t threadStackSizeInBytes = ThreadStackSize * K; 3838 if (threadStackSizeInBytes != 0 && 3839 threadStackSizeInBytes < Linux::min_stack_allowed) { 3840 tty->print_cr("\nThe stack size specified is too small, " 3841 "Specify at least %dk", 3842 Linux::min_stack_allowed / K); 3843 return JNI_ERR; 3844 } 3845 3846 // Make the stack size a multiple of the page size so that 3847 // the yellow/red zones can be guarded. 3848 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 3849 vm_page_size())); 3850 3851 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 3852 3853 Linux::libpthread_init(); 3854 if (PrintMiscellaneous && (Verbose || WizardMode)) { 3855 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n", 3856 Linux::glibc_version(), Linux::libpthread_version(), 3857 Linux::is_floating_stack() ? "floating stack" : "fixed stack"); 3858 } 3859 3860 if (UseNUMA) { 3861 if (!Linux::libnuma_init()) { 3862 UseNUMA = false; 3863 } else { 3864 if ((Linux::numa_max_node() < 1)) { 3865 // There's only one node(they start from 0), disable NUMA. 3866 UseNUMA = false; 3867 } 3868 } 3869 if (!UseNUMA && ForceNUMA) { 3870 UseNUMA = true; 3871 } 3872 } 3873 3874 if (MaxFDLimit) { 3875 // set the number of file descriptors to max. print out error 3876 // if getrlimit/setrlimit fails but continue regardless. 3877 struct rlimit nbr_files; 3878 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 3879 if (status != 0) { 3880 if (PrintMiscellaneous && (Verbose || WizardMode)) 3881 perror("os::init_2 getrlimit failed"); 3882 } else { 3883 nbr_files.rlim_cur = nbr_files.rlim_max; 3884 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 3885 if (status != 0) { 3886 if (PrintMiscellaneous && (Verbose || WizardMode)) 3887 perror("os::init_2 setrlimit failed"); 3888 } 3889 } 3890 } 3891 3892 // Initialize lock used to serialize thread creation (see os::create_thread) 3893 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 3894 3895 // Initialize HPI. 3896 jint hpi_result = hpi::initialize(); 3897 if (hpi_result != JNI_OK) { 3898 tty->print_cr("There was an error trying to initialize the HPI library."); 3899 return hpi_result; 3900 } 3901 3902 // at-exit methods are called in the reverse order of their registration. 3903 // atexit functions are called on return from main or as a result of a 3904 // call to exit(3C). There can be only 32 of these functions registered 3905 // and atexit() does not set errno. 3906 3907 if (PerfAllowAtExitRegistration) { 3908 // only register atexit functions if PerfAllowAtExitRegistration is set. 3909 // atexit functions can be delayed until process exit time, which 3910 // can be problematic for embedded VM situations. Embedded VMs should 3911 // call DestroyJavaVM() to assure that VM resources are released. 3912 3913 // note: perfMemory_exit_helper atexit function may be removed in 3914 // the future if the appropriate cleanup code can be added to the 3915 // VM_Exit VMOperation's doit method. 3916 if (atexit(perfMemory_exit_helper) != 0) { 3917 warning("os::init2 atexit(perfMemory_exit_helper) failed"); 3918 } 3919 } 3920 3921 // initialize thread priority policy 3922 prio_init(); 3923 3924 return JNI_OK; 3925 } 3926 3927 // Mark the polling page as unreadable 3928 void os::make_polling_page_unreadable(void) { 3929 if( !guard_memory((char*)_polling_page, Linux::page_size()) ) 3930 fatal("Could not disable polling page"); 3931 }; 3932 3933 // Mark the polling page as readable 3934 void os::make_polling_page_readable(void) { 3935 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 3936 fatal("Could not enable polling page"); 3937 } 3938 }; 3939 3940 int os::active_processor_count() { 3941 // Linux doesn't yet have a (official) notion of processor sets, 3942 // so just return the number of online processors. 3943 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 3944 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 3945 return online_cpus; 3946 } 3947 3948 bool os::distribute_processes(uint length, uint* distribution) { 3949 // Not yet implemented. 3950 return false; 3951 } 3952 3953 bool os::bind_to_processor(uint processor_id) { 3954 // Not yet implemented. 3955 return false; 3956 } 3957 3958 /// 3959 3960 // Suspends the target using the signal mechanism and then grabs the PC before 3961 // resuming the target. Used by the flat-profiler only 3962 ExtendedPC os::get_thread_pc(Thread* thread) { 3963 // Make sure that it is called by the watcher for the VMThread 3964 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 3965 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 3966 3967 ExtendedPC epc; 3968 3969 OSThread* osthread = thread->osthread(); 3970 if (do_suspend(osthread)) { 3971 if (osthread->ucontext() != NULL) { 3972 epc = os::Linux::ucontext_get_pc(osthread->ucontext()); 3973 } else { 3974 // NULL context is unexpected, double-check this is the VMThread 3975 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 3976 } 3977 do_resume(osthread); 3978 } 3979 // failure means pthread_kill failed for some reason - arguably this is 3980 // a fatal problem, but such problems are ignored elsewhere 3981 3982 return epc; 3983 } 3984 3985 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime) 3986 { 3987 if (is_NPTL()) { 3988 return pthread_cond_timedwait(_cond, _mutex, _abstime); 3989 } else { 3990 #ifndef IA64 3991 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control 3992 // word back to default 64bit precision if condvar is signaled. Java 3993 // wants 53bit precision. Save and restore current value. 3994 int fpu = get_fpu_control_word(); 3995 #endif // IA64 3996 int status = pthread_cond_timedwait(_cond, _mutex, _abstime); 3997 #ifndef IA64 3998 set_fpu_control_word(fpu); 3999 #endif // IA64 4000 return status; 4001 } 4002 } 4003 4004 //////////////////////////////////////////////////////////////////////////////// 4005 // debug support 4006 4007 #ifndef PRODUCT 4008 static address same_page(address x, address y) { 4009 int page_bits = -os::vm_page_size(); 4010 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits)) 4011 return x; 4012 else if (x > y) 4013 return (address)(intptr_t(y) | ~page_bits) + 1; 4014 else 4015 return (address)(intptr_t(y) & page_bits); 4016 } 4017 4018 bool os::find(address addr) { 4019 Dl_info dlinfo; 4020 memset(&dlinfo, 0, sizeof(dlinfo)); 4021 if (dladdr(addr, &dlinfo)) { 4022 tty->print(PTR_FORMAT ": ", addr); 4023 if (dlinfo.dli_sname != NULL) { 4024 tty->print("%s+%#x", dlinfo.dli_sname, 4025 addr - (intptr_t)dlinfo.dli_saddr); 4026 } else if (dlinfo.dli_fname) { 4027 tty->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 4028 } else { 4029 tty->print("<absolute address>"); 4030 } 4031 if (dlinfo.dli_fname) { 4032 tty->print(" in %s", dlinfo.dli_fname); 4033 } 4034 if (dlinfo.dli_fbase) { 4035 tty->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 4036 } 4037 tty->cr(); 4038 4039 if (Verbose) { 4040 // decode some bytes around the PC 4041 address begin = same_page(addr-40, addr); 4042 address end = same_page(addr+40, addr); 4043 address lowest = (address) dlinfo.dli_sname; 4044 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4045 if (begin < lowest) begin = lowest; 4046 Dl_info dlinfo2; 4047 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr 4048 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) 4049 end = (address) dlinfo2.dli_saddr; 4050 Disassembler::decode(begin, end); 4051 } 4052 return true; 4053 } 4054 return false; 4055 } 4056 4057 #endif 4058 4059 //////////////////////////////////////////////////////////////////////////////// 4060 // misc 4061 4062 // This does not do anything on Linux. This is basically a hook for being 4063 // able to use structured exception handling (thread-local exception filters) 4064 // on, e.g., Win32. 4065 void 4066 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 4067 JavaCallArguments* args, Thread* thread) { 4068 f(value, method, args, thread); 4069 } 4070 4071 void os::print_statistics() { 4072 } 4073 4074 int os::message_box(const char* title, const char* message) { 4075 int i; 4076 fdStream err(defaultStream::error_fd()); 4077 for (i = 0; i < 78; i++) err.print_raw("="); 4078 err.cr(); 4079 err.print_raw_cr(title); 4080 for (i = 0; i < 78; i++) err.print_raw("-"); 4081 err.cr(); 4082 err.print_raw_cr(message); 4083 for (i = 0; i < 78; i++) err.print_raw("="); 4084 err.cr(); 4085 4086 char buf[16]; 4087 // Prevent process from exiting upon "read error" without consuming all CPU 4088 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4089 4090 return buf[0] == 'y' || buf[0] == 'Y'; 4091 } 4092 4093 int os::stat(const char *path, struct stat *sbuf) { 4094 char pathbuf[MAX_PATH]; 4095 if (strlen(path) > MAX_PATH - 1) { 4096 errno = ENAMETOOLONG; 4097 return -1; 4098 } 4099 hpi::native_path(strcpy(pathbuf, path)); 4100 return ::stat(pathbuf, sbuf); 4101 } 4102 4103 bool os::check_heap(bool force) { 4104 return true; 4105 } 4106 4107 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) { 4108 return ::vsnprintf(buf, count, format, args); 4109 } 4110 4111 // Is a (classpath) directory empty? 4112 bool os::dir_is_empty(const char* path) { 4113 DIR *dir = NULL; 4114 struct dirent *ptr; 4115 4116 dir = opendir(path); 4117 if (dir == NULL) return true; 4118 4119 /* Scan the directory */ 4120 bool result = true; 4121 char buf[sizeof(struct dirent) + MAX_PATH]; 4122 while (result && (ptr = ::readdir(dir)) != NULL) { 4123 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 4124 result = false; 4125 } 4126 } 4127 closedir(dir); 4128 return result; 4129 } 4130 4131 // create binary file, rewriting existing file if required 4132 int os::create_binary_file(const char* path, bool rewrite_existing) { 4133 int oflags = O_WRONLY | O_CREAT; 4134 if (!rewrite_existing) { 4135 oflags |= O_EXCL; 4136 } 4137 return ::open64(path, oflags, S_IREAD | S_IWRITE); 4138 } 4139 4140 // return current position of file pointer 4141 jlong os::current_file_offset(int fd) { 4142 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 4143 } 4144 4145 // move file pointer to the specified offset 4146 jlong os::seek_to_file_offset(int fd, jlong offset) { 4147 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 4148 } 4149 4150 // Map a block of memory. 4151 char* os::map_memory(int fd, const char* file_name, size_t file_offset, 4152 char *addr, size_t bytes, bool read_only, 4153 bool allow_exec) { 4154 int prot; 4155 int flags; 4156 4157 if (read_only) { 4158 prot = PROT_READ; 4159 flags = MAP_SHARED; 4160 } else { 4161 prot = PROT_READ | PROT_WRITE; 4162 flags = MAP_PRIVATE; 4163 } 4164 4165 if (allow_exec) { 4166 prot |= PROT_EXEC; 4167 } 4168 4169 if (addr != NULL) { 4170 flags |= MAP_FIXED; 4171 } 4172 4173 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 4174 fd, file_offset); 4175 if (mapped_address == MAP_FAILED) { 4176 return NULL; 4177 } 4178 return mapped_address; 4179 } 4180 4181 4182 // Remap a block of memory. 4183 char* os::remap_memory(int fd, const char* file_name, size_t file_offset, 4184 char *addr, size_t bytes, bool read_only, 4185 bool allow_exec) { 4186 // same as map_memory() on this OS 4187 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 4188 allow_exec); 4189 } 4190 4191 4192 // Unmap a block of memory. 4193 bool os::unmap_memory(char* addr, size_t bytes) { 4194 return munmap(addr, bytes) == 0; 4195 } 4196 4197 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 4198 4199 static clockid_t thread_cpu_clockid(Thread* thread) { 4200 pthread_t tid = thread->osthread()->pthread_id(); 4201 clockid_t clockid; 4202 4203 // Get thread clockid 4204 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 4205 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 4206 return clockid; 4207 } 4208 4209 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 4210 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 4211 // of a thread. 4212 // 4213 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 4214 // the fast estimate available on the platform. 4215 4216 jlong os::current_thread_cpu_time() { 4217 if (os::Linux::supports_fast_thread_cpu_time()) { 4218 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4219 } else { 4220 // return user + sys since the cost is the same 4221 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 4222 } 4223 } 4224 4225 jlong os::thread_cpu_time(Thread* thread) { 4226 // consistent with what current_thread_cpu_time() returns 4227 if (os::Linux::supports_fast_thread_cpu_time()) { 4228 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4229 } else { 4230 return slow_thread_cpu_time(thread, true /* user + sys */); 4231 } 4232 } 4233 4234 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 4235 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4236 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4237 } else { 4238 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 4239 } 4240 } 4241 4242 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4243 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4244 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4245 } else { 4246 return slow_thread_cpu_time(thread, user_sys_cpu_time); 4247 } 4248 } 4249 4250 // 4251 // -1 on error. 4252 // 4253 4254 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4255 static bool proc_pid_cpu_avail = true; 4256 static bool proc_task_unchecked = true; 4257 static const char *proc_stat_path = "/proc/%d/stat"; 4258 pid_t tid = thread->osthread()->thread_id(); 4259 int i; 4260 char *s; 4261 char stat[2048]; 4262 int statlen; 4263 char proc_name[64]; 4264 int count; 4265 long sys_time, user_time; 4266 char string[64]; 4267 int idummy; 4268 long ldummy; 4269 FILE *fp; 4270 4271 // We first try accessing /proc/<pid>/cpu since this is faster to 4272 // process. If this file is not present (linux kernels 2.5 and above) 4273 // then we open /proc/<pid>/stat. 4274 if ( proc_pid_cpu_avail ) { 4275 sprintf(proc_name, "/proc/%d/cpu", tid); 4276 fp = fopen(proc_name, "r"); 4277 if ( fp != NULL ) { 4278 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time); 4279 fclose(fp); 4280 if ( count != 3 ) return -1; 4281 4282 if (user_sys_cpu_time) { 4283 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4284 } else { 4285 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4286 } 4287 } 4288 else proc_pid_cpu_avail = false; 4289 } 4290 4291 // The /proc/<tid>/stat aggregates per-process usage on 4292 // new Linux kernels 2.6+ where NPTL is supported. 4293 // The /proc/self/task/<tid>/stat still has the per-thread usage. 4294 // See bug 6328462. 4295 // There can be no directory /proc/self/task on kernels 2.4 with NPTL 4296 // and possibly in some other cases, so we check its availability. 4297 if (proc_task_unchecked && os::Linux::is_NPTL()) { 4298 // This is executed only once 4299 proc_task_unchecked = false; 4300 fp = fopen("/proc/self/task", "r"); 4301 if (fp != NULL) { 4302 proc_stat_path = "/proc/self/task/%d/stat"; 4303 fclose(fp); 4304 } 4305 } 4306 4307 sprintf(proc_name, proc_stat_path, tid); 4308 fp = fopen(proc_name, "r"); 4309 if ( fp == NULL ) return -1; 4310 statlen = fread(stat, 1, 2047, fp); 4311 stat[statlen] = '\0'; 4312 fclose(fp); 4313 4314 // Skip pid and the command string. Note that we could be dealing with 4315 // weird command names, e.g. user could decide to rename java launcher 4316 // to "java 1.4.2 :)", then the stat file would look like 4317 // 1234 (java 1.4.2 :)) R ... ... 4318 // We don't really need to know the command string, just find the last 4319 // occurrence of ")" and then start parsing from there. See bug 4726580. 4320 s = strrchr(stat, ')'); 4321 i = 0; 4322 if (s == NULL ) return -1; 4323 4324 // Skip blank chars 4325 do s++; while (isspace(*s)); 4326 4327 count = sscanf(s,"%*c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 4328 &idummy, &idummy, &idummy, &idummy, &idummy, 4329 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 4330 &user_time, &sys_time); 4331 if ( count != 12 ) return -1; 4332 if (user_sys_cpu_time) { 4333 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4334 } else { 4335 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4336 } 4337 } 4338 4339 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4340 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4341 info_ptr->may_skip_backward = false; // elapsed time not wall time 4342 info_ptr->may_skip_forward = false; // elapsed time not wall time 4343 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4344 } 4345 4346 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4347 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4348 info_ptr->may_skip_backward = false; // elapsed time not wall time 4349 info_ptr->may_skip_forward = false; // elapsed time not wall time 4350 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4351 } 4352 4353 bool os::is_thread_cpu_time_supported() { 4354 return true; 4355 } 4356 4357 // System loadavg support. Returns -1 if load average cannot be obtained. 4358 // Linux doesn't yet have a (official) notion of processor sets, 4359 // so just return the system wide load average. 4360 int os::loadavg(double loadavg[], int nelem) { 4361 return ::getloadavg(loadavg, nelem); 4362 } 4363 4364 void os::pause() { 4365 char filename[MAX_PATH]; 4366 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 4367 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 4368 } else { 4369 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 4370 } 4371 4372 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 4373 if (fd != -1) { 4374 struct stat buf; 4375 close(fd); 4376 while (::stat(filename, &buf) == 0) { 4377 (void)::poll(NULL, 0, 100); 4378 } 4379 } else { 4380 jio_fprintf(stderr, 4381 "Could not open pause file '%s', continuing immediately.\n", filename); 4382 } 4383 } 4384 4385 extern "C" { 4386 4387 /** 4388 * NOTE: the following code is to keep the green threads code 4389 * in the libjava.so happy. Once the green threads is removed, 4390 * these code will no longer be needed. 4391 */ 4392 int 4393 jdk_waitpid(pid_t pid, int* status, int options) { 4394 return waitpid(pid, status, options); 4395 } 4396 4397 int 4398 fork1() { 4399 return fork(); 4400 } 4401 4402 int 4403 jdk_sem_init(sem_t *sem, int pshared, unsigned int value) { 4404 return sem_init(sem, pshared, value); 4405 } 4406 4407 int 4408 jdk_sem_post(sem_t *sem) { 4409 return sem_post(sem); 4410 } 4411 4412 int 4413 jdk_sem_wait(sem_t *sem) { 4414 return sem_wait(sem); 4415 } 4416 4417 int 4418 jdk_pthread_sigmask(int how , const sigset_t* newmask, sigset_t* oldmask) { 4419 return pthread_sigmask(how , newmask, oldmask); 4420 } 4421 4422 } 4423 4424 // Refer to the comments in os_solaris.cpp park-unpark. 4425 // 4426 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 4427 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 4428 // For specifics regarding the bug see GLIBC BUGID 261237 : 4429 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 4430 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 4431 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 4432 // is used. (The simple C test-case provided in the GLIBC bug report manifests the 4433 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 4434 // and monitorenter when we're using 1-0 locking. All those operations may result in 4435 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 4436 // of libpthread avoids the problem, but isn't practical. 4437 // 4438 // Possible remedies: 4439 // 4440 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 4441 // This is palliative and probabilistic, however. If the thread is preempted 4442 // between the call to compute_abstime() and pthread_cond_timedwait(), more 4443 // than the minimum period may have passed, and the abstime may be stale (in the 4444 // past) resultin in a hang. Using this technique reduces the odds of a hang 4445 // but the JVM is still vulnerable, particularly on heavily loaded systems. 4446 // 4447 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 4448 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set 4449 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 4450 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant 4451 // thread. 4452 // 4453 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 4454 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 4455 // a timeout request to the chron thread and then blocking via pthread_cond_wait(). 4456 // This also works well. In fact it avoids kernel-level scalability impediments 4457 // on certain platforms that don't handle lots of active pthread_cond_timedwait() 4458 // timers in a graceful fashion. 4459 // 4460 // 4. When the abstime value is in the past it appears that control returns 4461 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 4462 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we 4463 // can avoid the problem by reinitializing the condvar -- by cond_destroy() 4464 // followed by cond_init() -- after all calls to pthread_cond_timedwait(). 4465 // It may be possible to avoid reinitialization by checking the return 4466 // value from pthread_cond_timedwait(). In addition to reinitializing the 4467 // condvar we must establish the invariant that cond_signal() is only called 4468 // within critical sections protected by the adjunct mutex. This prevents 4469 // cond_signal() from "seeing" a condvar that's in the midst of being 4470 // reinitialized or that is corrupt. Sadly, this invariant obviates the 4471 // desirable signal-after-unlock optimization that avoids futile context switching. 4472 // 4473 // I'm also concerned that some versions of NTPL might allocate an auxilliary 4474 // structure when a condvar is used or initialized. cond_destroy() would 4475 // release the helper structure. Our reinitialize-after-timedwait fix 4476 // put excessive stress on malloc/free and locks protecting the c-heap. 4477 // 4478 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 4479 // It may be possible to refine (4) by checking the kernel and NTPL verisons 4480 // and only enabling the work-around for vulnerable environments. 4481 4482 // utility to compute the abstime argument to timedwait: 4483 // millis is the relative timeout time 4484 // abstime will be the absolute timeout time 4485 // TODO: replace compute_abstime() with unpackTime() 4486 4487 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 4488 if (millis < 0) millis = 0; 4489 struct timeval now; 4490 int status = gettimeofday(&now, NULL); 4491 assert(status == 0, "gettimeofday"); 4492 jlong seconds = millis / 1000; 4493 millis %= 1000; 4494 if (seconds > 50000000) { // see man cond_timedwait(3T) 4495 seconds = 50000000; 4496 } 4497 abstime->tv_sec = now.tv_sec + seconds; 4498 long usec = now.tv_usec + millis * 1000; 4499 if (usec >= 1000000) { 4500 abstime->tv_sec += 1; 4501 usec -= 1000000; 4502 } 4503 abstime->tv_nsec = usec * 1000; 4504 return abstime; 4505 } 4506 4507 4508 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately. 4509 // Conceptually TryPark() should be equivalent to park(0). 4510 4511 int os::PlatformEvent::TryPark() { 4512 for (;;) { 4513 const int v = _Event ; 4514 guarantee ((v == 0) || (v == 1), "invariant") ; 4515 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ; 4516 } 4517 } 4518 4519 void os::PlatformEvent::park() { // AKA "down()" 4520 // Invariant: Only the thread associated with the Event/PlatformEvent 4521 // may call park(). 4522 // TODO: assert that _Assoc != NULL or _Assoc == Self 4523 int v ; 4524 for (;;) { 4525 v = _Event ; 4526 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 4527 } 4528 guarantee (v >= 0, "invariant") ; 4529 if (v == 0) { 4530 // Do this the hard way by blocking ... 4531 int status = pthread_mutex_lock(_mutex); 4532 assert_status(status == 0, status, "mutex_lock"); 4533 guarantee (_nParked == 0, "invariant") ; 4534 ++ _nParked ; 4535 while (_Event < 0) { 4536 status = pthread_cond_wait(_cond, _mutex); 4537 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 4538 // Treat this the same as if the wait was interrupted 4539 if (status == ETIME) { status = EINTR; } 4540 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 4541 } 4542 -- _nParked ; 4543 4544 // In theory we could move the ST of 0 into _Event past the unlock(), 4545 // but then we'd need a MEMBAR after the ST. 4546 _Event = 0 ; 4547 status = pthread_mutex_unlock(_mutex); 4548 assert_status(status == 0, status, "mutex_unlock"); 4549 } 4550 guarantee (_Event >= 0, "invariant") ; 4551 } 4552 4553 int os::PlatformEvent::park(jlong millis) { 4554 guarantee (_nParked == 0, "invariant") ; 4555 4556 int v ; 4557 for (;;) { 4558 v = _Event ; 4559 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 4560 } 4561 guarantee (v >= 0, "invariant") ; 4562 if (v != 0) return OS_OK ; 4563 4564 // We do this the hard way, by blocking the thread. 4565 // Consider enforcing a minimum timeout value. 4566 struct timespec abst; 4567 compute_abstime(&abst, millis); 4568 4569 int ret = OS_TIMEOUT; 4570 int status = pthread_mutex_lock(_mutex); 4571 assert_status(status == 0, status, "mutex_lock"); 4572 guarantee (_nParked == 0, "invariant") ; 4573 ++_nParked ; 4574 4575 // Object.wait(timo) will return because of 4576 // (a) notification 4577 // (b) timeout 4578 // (c) thread.interrupt 4579 // 4580 // Thread.interrupt and object.notify{All} both call Event::set. 4581 // That is, we treat thread.interrupt as a special case of notification. 4582 // The underlying Solaris implementation, cond_timedwait, admits 4583 // spurious/premature wakeups, but the JLS/JVM spec prevents the 4584 // JVM from making those visible to Java code. As such, we must 4585 // filter out spurious wakeups. We assume all ETIME returns are valid. 4586 // 4587 // TODO: properly differentiate simultaneous notify+interrupt. 4588 // In that case, we should propagate the notify to another waiter. 4589 4590 while (_Event < 0) { 4591 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst); 4592 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 4593 pthread_cond_destroy (_cond); 4594 pthread_cond_init (_cond, NULL) ; 4595 } 4596 assert_status(status == 0 || status == EINTR || 4597 status == ETIME || status == ETIMEDOUT, 4598 status, "cond_timedwait"); 4599 if (!FilterSpuriousWakeups) break ; // previous semantics 4600 if (status == ETIME || status == ETIMEDOUT) break ; 4601 // We consume and ignore EINTR and spurious wakeups. 4602 } 4603 --_nParked ; 4604 if (_Event >= 0) { 4605 ret = OS_OK; 4606 } 4607 _Event = 0 ; 4608 status = pthread_mutex_unlock(_mutex); 4609 assert_status(status == 0, status, "mutex_unlock"); 4610 assert (_nParked == 0, "invariant") ; 4611 return ret; 4612 } 4613 4614 void os::PlatformEvent::unpark() { 4615 int v, AnyWaiters ; 4616 for (;;) { 4617 v = _Event ; 4618 if (v > 0) { 4619 // The LD of _Event could have reordered or be satisfied 4620 // by a read-aside from this processor's write buffer. 4621 // To avoid problems execute a barrier and then 4622 // ratify the value. 4623 OrderAccess::fence() ; 4624 if (_Event == v) return ; 4625 continue ; 4626 } 4627 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ; 4628 } 4629 if (v < 0) { 4630 // Wait for the thread associated with the event to vacate 4631 int status = pthread_mutex_lock(_mutex); 4632 assert_status(status == 0, status, "mutex_lock"); 4633 AnyWaiters = _nParked ; 4634 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ; 4635 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 4636 AnyWaiters = 0 ; 4637 pthread_cond_signal (_cond); 4638 } 4639 status = pthread_mutex_unlock(_mutex); 4640 assert_status(status == 0, status, "mutex_unlock"); 4641 if (AnyWaiters != 0) { 4642 status = pthread_cond_signal(_cond); 4643 assert_status(status == 0, status, "cond_signal"); 4644 } 4645 } 4646 4647 // Note that we signal() _after dropping the lock for "immortal" Events. 4648 // This is safe and avoids a common class of futile wakeups. In rare 4649 // circumstances this can cause a thread to return prematurely from 4650 // cond_{timed}wait() but the spurious wakeup is benign and the victim will 4651 // simply re-test the condition and re-park itself. 4652 } 4653 4654 4655 // JSR166 4656 // ------------------------------------------------------- 4657 4658 /* 4659 * The solaris and linux implementations of park/unpark are fairly 4660 * conservative for now, but can be improved. They currently use a 4661 * mutex/condvar pair, plus a a count. 4662 * Park decrements count if > 0, else does a condvar wait. Unpark 4663 * sets count to 1 and signals condvar. Only one thread ever waits 4664 * on the condvar. Contention seen when trying to park implies that someone 4665 * is unparking you, so don't wait. And spurious returns are fine, so there 4666 * is no need to track notifications. 4667 */ 4668 4669 4670 #define NANOSECS_PER_SEC 1000000000 4671 #define NANOSECS_PER_MILLISEC 1000000 4672 #define MAX_SECS 100000000 4673 /* 4674 * This code is common to linux and solaris and will be moved to a 4675 * common place in dolphin. 4676 * 4677 * The passed in time value is either a relative time in nanoseconds 4678 * or an absolute time in milliseconds. Either way it has to be unpacked 4679 * into suitable seconds and nanoseconds components and stored in the 4680 * given timespec structure. 4681 * Given time is a 64-bit value and the time_t used in the timespec is only 4682 * a signed-32-bit value (except on 64-bit Linux) we have to watch for 4683 * overflow if times way in the future are given. Further on Solaris versions 4684 * prior to 10 there is a restriction (see cond_timedwait) that the specified 4685 * number of seconds, in abstime, is less than current_time + 100,000,000. 4686 * As it will be 28 years before "now + 100000000" will overflow we can 4687 * ignore overflow and just impose a hard-limit on seconds using the value 4688 * of "now + 100,000,000". This places a limit on the timeout of about 3.17 4689 * years from "now". 4690 */ 4691 4692 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 4693 assert (time > 0, "convertTime"); 4694 4695 struct timeval now; 4696 int status = gettimeofday(&now, NULL); 4697 assert(status == 0, "gettimeofday"); 4698 4699 time_t max_secs = now.tv_sec + MAX_SECS; 4700 4701 if (isAbsolute) { 4702 jlong secs = time / 1000; 4703 if (secs > max_secs) { 4704 absTime->tv_sec = max_secs; 4705 } 4706 else { 4707 absTime->tv_sec = secs; 4708 } 4709 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 4710 } 4711 else { 4712 jlong secs = time / NANOSECS_PER_SEC; 4713 if (secs >= MAX_SECS) { 4714 absTime->tv_sec = max_secs; 4715 absTime->tv_nsec = 0; 4716 } 4717 else { 4718 absTime->tv_sec = now.tv_sec + secs; 4719 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 4720 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 4721 absTime->tv_nsec -= NANOSECS_PER_SEC; 4722 ++absTime->tv_sec; // note: this must be <= max_secs 4723 } 4724 } 4725 } 4726 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 4727 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 4728 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 4729 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 4730 } 4731 4732 void Parker::park(bool isAbsolute, jlong time) { 4733 // Optional fast-path check: 4734 // Return immediately if a permit is available. 4735 if (_counter > 0) { 4736 _counter = 0 ; 4737 OrderAccess::fence(); 4738 return ; 4739 } 4740 4741 Thread* thread = Thread::current(); 4742 assert(thread->is_Java_thread(), "Must be JavaThread"); 4743 JavaThread *jt = (JavaThread *)thread; 4744 4745 // Optional optimization -- avoid state transitions if there's an interrupt pending. 4746 // Check interrupt before trying to wait 4747 if (Thread::is_interrupted(thread, false)) { 4748 return; 4749 } 4750 4751 // Next, demultiplex/decode time arguments 4752 timespec absTime; 4753 if (time < 0) { // don't wait at all 4754 return; 4755 } 4756 if (time > 0) { 4757 unpackTime(&absTime, isAbsolute, time); 4758 } 4759 4760 4761 // Enter safepoint region 4762 // Beware of deadlocks such as 6317397. 4763 // The per-thread Parker:: mutex is a classic leaf-lock. 4764 // In particular a thread must never block on the Threads_lock while 4765 // holding the Parker:: mutex. If safepoints are pending both the 4766 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 4767 ThreadBlockInVM tbivm(jt); 4768 4769 // Don't wait if cannot get lock since interference arises from 4770 // unblocking. Also. check interrupt before trying wait 4771 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 4772 return; 4773 } 4774 4775 int status ; 4776 if (_counter > 0) { // no wait needed 4777 _counter = 0; 4778 status = pthread_mutex_unlock(_mutex); 4779 assert (status == 0, "invariant") ; 4780 OrderAccess::fence(); 4781 return; 4782 } 4783 4784 #ifdef ASSERT 4785 // Don't catch signals while blocked; let the running threads have the signals. 4786 // (This allows a debugger to break into the running thread.) 4787 sigset_t oldsigs; 4788 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 4789 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 4790 #endif 4791 4792 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 4793 jt->set_suspend_equivalent(); 4794 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 4795 4796 if (time == 0) { 4797 status = pthread_cond_wait (_cond, _mutex) ; 4798 } else { 4799 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ; 4800 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 4801 pthread_cond_destroy (_cond) ; 4802 pthread_cond_init (_cond, NULL); 4803 } 4804 } 4805 assert_status(status == 0 || status == EINTR || 4806 status == ETIME || status == ETIMEDOUT, 4807 status, "cond_timedwait"); 4808 4809 #ifdef ASSERT 4810 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 4811 #endif 4812 4813 _counter = 0 ; 4814 status = pthread_mutex_unlock(_mutex) ; 4815 assert_status(status == 0, status, "invariant") ; 4816 // If externally suspended while waiting, re-suspend 4817 if (jt->handle_special_suspend_equivalent_condition()) { 4818 jt->java_suspend_self(); 4819 } 4820 4821 OrderAccess::fence(); 4822 } 4823 4824 void Parker::unpark() { 4825 int s, status ; 4826 status = pthread_mutex_lock(_mutex); 4827 assert (status == 0, "invariant") ; 4828 s = _counter; 4829 _counter = 1; 4830 if (s < 1) { 4831 if (WorkAroundNPTLTimedWaitHang) { 4832 status = pthread_cond_signal (_cond) ; 4833 assert (status == 0, "invariant") ; 4834 status = pthread_mutex_unlock(_mutex); 4835 assert (status == 0, "invariant") ; 4836 } else { 4837 status = pthread_mutex_unlock(_mutex); 4838 assert (status == 0, "invariant") ; 4839 status = pthread_cond_signal (_cond) ; 4840 assert (status == 0, "invariant") ; 4841 } 4842 } else { 4843 pthread_mutex_unlock(_mutex); 4844 assert (status == 0, "invariant") ; 4845 } 4846 } 4847 4848 4849 extern char** environ; 4850 4851 #ifndef __NR_fork 4852 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) 4853 #endif 4854 4855 #ifndef __NR_execve 4856 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) 4857 #endif 4858 4859 // Run the specified command in a separate process. Return its exit value, 4860 // or -1 on failure (e.g. can't fork a new process). 4861 // Unlike system(), this function can be called from signal handler. It 4862 // doesn't block SIGINT et al. 4863 int os::fork_and_exec(char* cmd) { 4864 const char * argv[4] = {"sh", "-c", cmd, NULL}; 4865 4866 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run 4867 // pthread_atfork handlers and reset pthread library. All we need is a 4868 // separate process to execve. Make a direct syscall to fork process. 4869 // On IA64 there's no fork syscall, we have to use fork() and hope for 4870 // the best... 4871 pid_t pid = NOT_IA64(syscall(__NR_fork);) 4872 IA64_ONLY(fork();) 4873 4874 if (pid < 0) { 4875 // fork failed 4876 return -1; 4877 4878 } else if (pid == 0) { 4879 // child process 4880 4881 // execve() in LinuxThreads will call pthread_kill_other_threads_np() 4882 // first to kill every thread on the thread list. Because this list is 4883 // not reset by fork() (see notes above), execve() will instead kill 4884 // every thread in the parent process. We know this is the only thread 4885 // in the new process, so make a system call directly. 4886 // IA64 should use normal execve() from glibc to match the glibc fork() 4887 // above. 4888 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);) 4889 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);) 4890 4891 // execve failed 4892 _exit(-1); 4893 4894 } else { 4895 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 4896 // care about the actual exit code, for now. 4897 4898 int status; 4899 4900 // Wait for the child process to exit. This returns immediately if 4901 // the child has already exited. */ 4902 while (waitpid(pid, &status, 0) < 0) { 4903 switch (errno) { 4904 case ECHILD: return 0; 4905 case EINTR: break; 4906 default: return -1; 4907 } 4908 } 4909 4910 if (WIFEXITED(status)) { 4911 // The child exited normally; get its exit code. 4912 return WEXITSTATUS(status); 4913 } else if (WIFSIGNALED(status)) { 4914 // The child exited because of a signal 4915 // The best value to return is 0x80 + signal number, 4916 // because that is what all Unix shells do, and because 4917 // it allows callers to distinguish between process exit and 4918 // process death by signal. 4919 return 0x80 + WTERMSIG(status); 4920 } else { 4921 // Unknown exit code; pass it through 4922 return status; 4923 } 4924 } 4925 }