1 /* 2 * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 # define __STDC_FORMAT_MACROS 26 27 // no precompiled headers 28 #include "classfile/classLoader.hpp" 29 #include "classfile/systemDictionary.hpp" 30 #include "classfile/vmSymbols.hpp" 31 #include "code/icBuffer.hpp" 32 #include "code/vtableStubs.hpp" 33 #include "compiler/compileBroker.hpp" 34 #include "interpreter/interpreter.hpp" 35 #include "jvm_linux.h" 36 #include "memory/allocation.inline.hpp" 37 #include "memory/filemap.hpp" 38 #include "mutex_linux.inline.hpp" 39 #include "oops/oop.inline.hpp" 40 #include "os_share_linux.hpp" 41 #include "prims/jniFastGetField.hpp" 42 #include "prims/jvm.h" 43 #include "prims/jvm_misc.hpp" 44 #include "runtime/arguments.hpp" 45 #include "runtime/extendedPC.hpp" 46 #include "runtime/globals.hpp" 47 #include "runtime/hpi.hpp" 48 #include "runtime/interfaceSupport.hpp" 49 #include "runtime/java.hpp" 50 #include "runtime/javaCalls.hpp" 51 #include "runtime/mutexLocker.hpp" 52 #include "runtime/objectMonitor.hpp" 53 #include "runtime/objectMonitor.inline.hpp" 54 #include "runtime/osThread.hpp" 55 #include "runtime/perfMemory.hpp" 56 #include "runtime/sharedRuntime.hpp" 57 #include "runtime/statSampler.hpp" 58 #include "runtime/stubRoutines.hpp" 59 #include "runtime/threadCritical.hpp" 60 #include "runtime/timer.hpp" 61 #include "services/attachListener.hpp" 62 #include "services/runtimeService.hpp" 63 #include "thread_linux.inline.hpp" 64 #include "utilities/defaultStream.hpp" 65 #include "utilities/events.hpp" 66 #include "utilities/growableArray.hpp" 67 #include "utilities/vmError.hpp" 68 #ifdef TARGET_ARCH_x86 69 # include "assembler_x86.inline.hpp" 70 # include "nativeInst_x86.hpp" 71 #endif 72 #ifdef TARGET_ARCH_sparc 73 # include "assembler_sparc.inline.hpp" 74 # include "nativeInst_sparc.hpp" 75 #endif 76 #ifdef TARGET_ARCH_zero 77 # include "assembler_zero.inline.hpp" 78 # include "nativeInst_zero.hpp" 79 #endif 80 #ifdef COMPILER1 81 #include "c1/c1_Runtime1.hpp" 82 #endif 83 #ifdef COMPILER2 84 #include "opto/runtime.hpp" 85 #endif 86 87 // do not include precompiled header file 88 // put OS-includes here 89 # include <sys/types.h> 90 # include <sys/mman.h> 91 # include <sys/stat.h> 92 # include <sys/select.h> 93 # include <pthread.h> 94 # include <signal.h> 95 # include <errno.h> 96 # include <dlfcn.h> 97 # include <stdio.h> 98 # include <unistd.h> 99 # include <sys/resource.h> 100 # include <pthread.h> 101 # include <sys/stat.h> 102 # include <sys/time.h> 103 # include <sys/times.h> 104 # include <sys/utsname.h> 105 # include <sys/socket.h> 106 # include <sys/wait.h> 107 # include <pwd.h> 108 # include <poll.h> 109 # include <semaphore.h> 110 # include <fcntl.h> 111 # include <string.h> 112 # include <syscall.h> 113 # include <sys/sysinfo.h> 114 # include <gnu/libc-version.h> 115 # include <sys/ipc.h> 116 # include <sys/shm.h> 117 # include <link.h> 118 # include <stdint.h> 119 # include <inttypes.h> 120 121 #define MAX_PATH (2 * K) 122 123 // for timer info max values which include all bits 124 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 125 #define SEC_IN_NANOSECS 1000000000LL 126 127 //////////////////////////////////////////////////////////////////////////////// 128 // global variables 129 julong os::Linux::_physical_memory = 0; 130 131 address os::Linux::_initial_thread_stack_bottom = NULL; 132 uintptr_t os::Linux::_initial_thread_stack_size = 0; 133 134 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 135 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 136 Mutex* os::Linux::_createThread_lock = NULL; 137 pthread_t os::Linux::_main_thread; 138 int os::Linux::_page_size = -1; 139 bool os::Linux::_is_floating_stack = false; 140 bool os::Linux::_is_NPTL = false; 141 bool os::Linux::_supports_fast_thread_cpu_time = false; 142 const char * os::Linux::_glibc_version = NULL; 143 const char * os::Linux::_libpthread_version = NULL; 144 145 static jlong initial_time_count=0; 146 147 static int clock_tics_per_sec = 100; 148 149 // For diagnostics to print a message once. see run_periodic_checks 150 static sigset_t check_signal_done; 151 static bool check_signals = true;; 152 153 static pid_t _initial_pid = 0; 154 155 /* Signal number used to suspend/resume a thread */ 156 157 /* do not use any signal number less than SIGSEGV, see 4355769 */ 158 static int SR_signum = SIGUSR2; 159 sigset_t SR_sigset; 160 161 /* Used to protect dlsym() calls */ 162 static pthread_mutex_t dl_mutex; 163 164 //////////////////////////////////////////////////////////////////////////////// 165 // utility functions 166 167 static int SR_initialize(); 168 static int SR_finalize(); 169 170 julong os::available_memory() { 171 return Linux::available_memory(); 172 } 173 174 julong os::Linux::available_memory() { 175 // values in struct sysinfo are "unsigned long" 176 struct sysinfo si; 177 sysinfo(&si); 178 179 return (julong)si.freeram * si.mem_unit; 180 } 181 182 julong os::physical_memory() { 183 return Linux::physical_memory(); 184 } 185 186 julong os::allocatable_physical_memory(julong size) { 187 #ifdef _LP64 188 return size; 189 #else 190 julong result = MIN2(size, (julong)3800*M); 191 if (!is_allocatable(result)) { 192 // See comments under solaris for alignment considerations 193 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size(); 194 result = MIN2(size, reasonable_size); 195 } 196 return result; 197 #endif // _LP64 198 } 199 200 //////////////////////////////////////////////////////////////////////////////// 201 // environment support 202 203 bool os::getenv(const char* name, char* buf, int len) { 204 const char* val = ::getenv(name); 205 if (val != NULL && strlen(val) < (size_t)len) { 206 strcpy(buf, val); 207 return true; 208 } 209 if (len > 0) buf[0] = 0; // return a null string 210 return false; 211 } 212 213 214 // Return true if user is running as root. 215 216 bool os::have_special_privileges() { 217 static bool init = false; 218 static bool privileges = false; 219 if (!init) { 220 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 221 init = true; 222 } 223 return privileges; 224 } 225 226 227 #ifndef SYS_gettid 228 // i386: 224, ia64: 1105, amd64: 186, sparc 143 229 #ifdef __ia64__ 230 #define SYS_gettid 1105 231 #elif __i386__ 232 #define SYS_gettid 224 233 #elif __amd64__ 234 #define SYS_gettid 186 235 #elif __sparc__ 236 #define SYS_gettid 143 237 #else 238 #error define gettid for the arch 239 #endif 240 #endif 241 242 // Cpu architecture string 243 #if defined(ZERO) 244 static char cpu_arch[] = ZERO_LIBARCH; 245 #elif defined(IA64) 246 static char cpu_arch[] = "ia64"; 247 #elif defined(IA32) 248 static char cpu_arch[] = "i386"; 249 #elif defined(AMD64) 250 static char cpu_arch[] = "amd64"; 251 #elif defined(ARM) 252 static char cpu_arch[] = "arm"; 253 #elif defined(PPC) 254 static char cpu_arch[] = "ppc"; 255 #elif defined(SPARC) 256 # ifdef _LP64 257 static char cpu_arch[] = "sparcv9"; 258 # else 259 static char cpu_arch[] = "sparc"; 260 # endif 261 #else 262 #error Add appropriate cpu_arch setting 263 #endif 264 265 266 // pid_t gettid() 267 // 268 // Returns the kernel thread id of the currently running thread. Kernel 269 // thread id is used to access /proc. 270 // 271 // (Note that getpid() on LinuxThreads returns kernel thread id too; but 272 // on NPTL, it returns the same pid for all threads, as required by POSIX.) 273 // 274 pid_t os::Linux::gettid() { 275 int rslt = syscall(SYS_gettid); 276 if (rslt == -1) { 277 // old kernel, no NPTL support 278 return getpid(); 279 } else { 280 return (pid_t)rslt; 281 } 282 } 283 284 // Most versions of linux have a bug where the number of processors are 285 // determined by looking at the /proc file system. In a chroot environment, 286 // the system call returns 1. This causes the VM to act as if it is 287 // a single processor and elide locking (see is_MP() call). 288 static bool unsafe_chroot_detected = false; 289 static const char *unstable_chroot_error = "/proc file system not found.\n" 290 "Java may be unstable running multithreaded in a chroot " 291 "environment on Linux when /proc filesystem is not mounted."; 292 293 void os::Linux::initialize_system_info() { 294 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 295 if (processor_count() == 1) { 296 pid_t pid = os::Linux::gettid(); 297 char fname[32]; 298 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 299 FILE *fp = fopen(fname, "r"); 300 if (fp == NULL) { 301 unsafe_chroot_detected = true; 302 } else { 303 fclose(fp); 304 } 305 } 306 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 307 assert(processor_count() > 0, "linux error"); 308 } 309 310 void os::init_system_properties_values() { 311 // char arch[12]; 312 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch)); 313 314 // The next steps are taken in the product version: 315 // 316 // Obtain the JAVA_HOME value from the location of libjvm[_g].so. 317 // This library should be located at: 318 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so. 319 // 320 // If "/jre/lib/" appears at the right place in the path, then we 321 // assume libjvm[_g].so is installed in a JDK and we use this path. 322 // 323 // Otherwise exit with message: "Could not create the Java virtual machine." 324 // 325 // The following extra steps are taken in the debugging version: 326 // 327 // If "/jre/lib/" does NOT appear at the right place in the path 328 // instead of exit check for $JAVA_HOME environment variable. 329 // 330 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 331 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so 332 // it looks like libjvm[_g].so is installed there 333 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so. 334 // 335 // Otherwise exit. 336 // 337 // Important note: if the location of libjvm.so changes this 338 // code needs to be changed accordingly. 339 340 // The next few definitions allow the code to be verbatim: 341 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n)) 342 #define getenv(n) ::getenv(n) 343 344 /* 345 * See ld(1): 346 * The linker uses the following search paths to locate required 347 * shared libraries: 348 * 1: ... 349 * ... 350 * 7: The default directories, normally /lib and /usr/lib. 351 */ 352 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 353 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 354 #else 355 #define DEFAULT_LIBPATH "/lib:/usr/lib" 356 #endif 357 358 #define EXTENSIONS_DIR "/lib/ext" 359 #define ENDORSED_DIR "/lib/endorsed" 360 #define REG_DIR "/usr/java/packages" 361 362 { 363 /* sysclasspath, java_home, dll_dir */ 364 { 365 char *home_path; 366 char *dll_path; 367 char *pslash; 368 char buf[MAXPATHLEN]; 369 os::jvm_path(buf, sizeof(buf)); 370 371 // Found the full path to libjvm.so. 372 // Now cut the path to <java_home>/jre if we can. 373 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */ 374 pslash = strrchr(buf, '/'); 375 if (pslash != NULL) 376 *pslash = '\0'; /* get rid of /{client|server|hotspot} */ 377 dll_path = malloc(strlen(buf) + 1); 378 if (dll_path == NULL) 379 return; 380 strcpy(dll_path, buf); 381 Arguments::set_dll_dir(dll_path); 382 383 if (pslash != NULL) { 384 pslash = strrchr(buf, '/'); 385 if (pslash != NULL) { 386 *pslash = '\0'; /* get rid of /<arch> */ 387 pslash = strrchr(buf, '/'); 388 if (pslash != NULL) 389 *pslash = '\0'; /* get rid of /lib */ 390 } 391 } 392 393 home_path = malloc(strlen(buf) + 1); 394 if (home_path == NULL) 395 return; 396 strcpy(home_path, buf); 397 Arguments::set_java_home(home_path); 398 399 if (!set_boot_path('/', ':')) 400 return; 401 } 402 403 /* 404 * Where to look for native libraries 405 * 406 * Note: Due to a legacy implementation, most of the library path 407 * is set in the launcher. This was to accomodate linking restrictions 408 * on legacy Linux implementations (which are no longer supported). 409 * Eventually, all the library path setting will be done here. 410 * 411 * However, to prevent the proliferation of improperly built native 412 * libraries, the new path component /usr/java/packages is added here. 413 * Eventually, all the library path setting will be done here. 414 */ 415 { 416 char *ld_library_path; 417 418 /* 419 * Construct the invariant part of ld_library_path. Note that the 420 * space for the colon and the trailing null are provided by the 421 * nulls included by the sizeof operator (so actually we allocate 422 * a byte more than necessary). 423 */ 424 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") + 425 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH)); 426 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch); 427 428 /* 429 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It 430 * should always exist (until the legacy problem cited above is 431 * addressed). 432 */ 433 char *v = getenv("LD_LIBRARY_PATH"); 434 if (v != NULL) { 435 char *t = ld_library_path; 436 /* That's +1 for the colon and +1 for the trailing '\0' */ 437 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1); 438 sprintf(ld_library_path, "%s:%s", v, t); 439 } 440 Arguments::set_library_path(ld_library_path); 441 } 442 443 /* 444 * Extensions directories. 445 * 446 * Note that the space for the colon and the trailing null are provided 447 * by the nulls included by the sizeof operator (so actually one byte more 448 * than necessary is allocated). 449 */ 450 { 451 char *buf = malloc(strlen(Arguments::get_java_home()) + 452 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR)); 453 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR, 454 Arguments::get_java_home()); 455 Arguments::set_ext_dirs(buf); 456 } 457 458 /* Endorsed standards default directory. */ 459 { 460 char * buf; 461 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR)); 462 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home()); 463 Arguments::set_endorsed_dirs(buf); 464 } 465 } 466 467 #undef malloc 468 #undef getenv 469 #undef EXTENSIONS_DIR 470 #undef ENDORSED_DIR 471 472 // Done 473 return; 474 } 475 476 //////////////////////////////////////////////////////////////////////////////// 477 // breakpoint support 478 479 void os::breakpoint() { 480 BREAKPOINT; 481 } 482 483 extern "C" void breakpoint() { 484 // use debugger to set breakpoint here 485 } 486 487 //////////////////////////////////////////////////////////////////////////////// 488 // signal support 489 490 debug_only(static bool signal_sets_initialized = false); 491 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 492 493 bool os::Linux::is_sig_ignored(int sig) { 494 struct sigaction oact; 495 sigaction(sig, (struct sigaction*)NULL, &oact); 496 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 497 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 498 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) 499 return true; 500 else 501 return false; 502 } 503 504 void os::Linux::signal_sets_init() { 505 // Should also have an assertion stating we are still single-threaded. 506 assert(!signal_sets_initialized, "Already initialized"); 507 // Fill in signals that are necessarily unblocked for all threads in 508 // the VM. Currently, we unblock the following signals: 509 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 510 // by -Xrs (=ReduceSignalUsage)); 511 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 512 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 513 // the dispositions or masks wrt these signals. 514 // Programs embedding the VM that want to use the above signals for their 515 // own purposes must, at this time, use the "-Xrs" option to prevent 516 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 517 // (See bug 4345157, and other related bugs). 518 // In reality, though, unblocking these signals is really a nop, since 519 // these signals are not blocked by default. 520 sigemptyset(&unblocked_sigs); 521 sigemptyset(&allowdebug_blocked_sigs); 522 sigaddset(&unblocked_sigs, SIGILL); 523 sigaddset(&unblocked_sigs, SIGSEGV); 524 sigaddset(&unblocked_sigs, SIGBUS); 525 sigaddset(&unblocked_sigs, SIGFPE); 526 sigaddset(&unblocked_sigs, SR_signum); 527 528 if (!ReduceSignalUsage) { 529 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 530 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 531 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 532 } 533 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 534 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 535 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 536 } 537 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 538 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 539 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 540 } 541 } 542 // Fill in signals that are blocked by all but the VM thread. 543 sigemptyset(&vm_sigs); 544 if (!ReduceSignalUsage) 545 sigaddset(&vm_sigs, BREAK_SIGNAL); 546 debug_only(signal_sets_initialized = true); 547 548 } 549 550 // These are signals that are unblocked while a thread is running Java. 551 // (For some reason, they get blocked by default.) 552 sigset_t* os::Linux::unblocked_signals() { 553 assert(signal_sets_initialized, "Not initialized"); 554 return &unblocked_sigs; 555 } 556 557 // These are the signals that are blocked while a (non-VM) thread is 558 // running Java. Only the VM thread handles these signals. 559 sigset_t* os::Linux::vm_signals() { 560 assert(signal_sets_initialized, "Not initialized"); 561 return &vm_sigs; 562 } 563 564 // These are signals that are blocked during cond_wait to allow debugger in 565 sigset_t* os::Linux::allowdebug_blocked_signals() { 566 assert(signal_sets_initialized, "Not initialized"); 567 return &allowdebug_blocked_sigs; 568 } 569 570 void os::Linux::hotspot_sigmask(Thread* thread) { 571 572 //Save caller's signal mask before setting VM signal mask 573 sigset_t caller_sigmask; 574 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 575 576 OSThread* osthread = thread->osthread(); 577 osthread->set_caller_sigmask(caller_sigmask); 578 579 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 580 581 if (!ReduceSignalUsage) { 582 if (thread->is_VM_thread()) { 583 // Only the VM thread handles BREAK_SIGNAL ... 584 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 585 } else { 586 // ... all other threads block BREAK_SIGNAL 587 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 588 } 589 } 590 } 591 592 ////////////////////////////////////////////////////////////////////////////// 593 // detecting pthread library 594 595 void os::Linux::libpthread_init() { 596 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION 597 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a 598 // generic name for earlier versions. 599 // Define macros here so we can build HotSpot on old systems. 600 # ifndef _CS_GNU_LIBC_VERSION 601 # define _CS_GNU_LIBC_VERSION 2 602 # endif 603 # ifndef _CS_GNU_LIBPTHREAD_VERSION 604 # define _CS_GNU_LIBPTHREAD_VERSION 3 605 # endif 606 607 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 608 if (n > 0) { 609 char *str = (char *)malloc(n); 610 confstr(_CS_GNU_LIBC_VERSION, str, n); 611 os::Linux::set_glibc_version(str); 612 } else { 613 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version() 614 static char _gnu_libc_version[32]; 615 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version), 616 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release()); 617 os::Linux::set_glibc_version(_gnu_libc_version); 618 } 619 620 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 621 if (n > 0) { 622 char *str = (char *)malloc(n); 623 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 624 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells 625 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this 626 // is the case. LinuxThreads has a hard limit on max number of threads. 627 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value. 628 // On the other hand, NPTL does not have such a limit, sysconf() 629 // will return -1 and errno is not changed. Check if it is really NPTL. 630 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 && 631 strstr(str, "NPTL") && 632 sysconf(_SC_THREAD_THREADS_MAX) > 0) { 633 free(str); 634 os::Linux::set_libpthread_version("linuxthreads"); 635 } else { 636 os::Linux::set_libpthread_version(str); 637 } 638 } else { 639 // glibc before 2.3.2 only has LinuxThreads. 640 os::Linux::set_libpthread_version("linuxthreads"); 641 } 642 643 if (strstr(libpthread_version(), "NPTL")) { 644 os::Linux::set_is_NPTL(); 645 } else { 646 os::Linux::set_is_LinuxThreads(); 647 } 648 649 // LinuxThreads have two flavors: floating-stack mode, which allows variable 650 // stack size; and fixed-stack mode. NPTL is always floating-stack. 651 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) { 652 os::Linux::set_is_floating_stack(); 653 } 654 } 655 656 ///////////////////////////////////////////////////////////////////////////// 657 // thread stack 658 659 // Force Linux kernel to expand current thread stack. If "bottom" is close 660 // to the stack guard, caller should block all signals. 661 // 662 // MAP_GROWSDOWN: 663 // A special mmap() flag that is used to implement thread stacks. It tells 664 // kernel that the memory region should extend downwards when needed. This 665 // allows early versions of LinuxThreads to only mmap the first few pages 666 // when creating a new thread. Linux kernel will automatically expand thread 667 // stack as needed (on page faults). 668 // 669 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 670 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 671 // region, it's hard to tell if the fault is due to a legitimate stack 672 // access or because of reading/writing non-exist memory (e.g. buffer 673 // overrun). As a rule, if the fault happens below current stack pointer, 674 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 675 // application (see Linux kernel fault.c). 676 // 677 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 678 // stack overflow detection. 679 // 680 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 681 // not use this flag. However, the stack of initial thread is not created 682 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though 683 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack 684 // and then attach the thread to JVM. 685 // 686 // To get around the problem and allow stack banging on Linux, we need to 687 // manually expand thread stack after receiving the SIGSEGV. 688 // 689 // There are two ways to expand thread stack to address "bottom", we used 690 // both of them in JVM before 1.5: 691 // 1. adjust stack pointer first so that it is below "bottom", and then 692 // touch "bottom" 693 // 2. mmap() the page in question 694 // 695 // Now alternate signal stack is gone, it's harder to use 2. For instance, 696 // if current sp is already near the lower end of page 101, and we need to 697 // call mmap() to map page 100, it is possible that part of the mmap() frame 698 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 699 // That will destroy the mmap() frame and cause VM to crash. 700 // 701 // The following code works by adjusting sp first, then accessing the "bottom" 702 // page to force a page fault. Linux kernel will then automatically expand the 703 // stack mapping. 704 // 705 // _expand_stack_to() assumes its frame size is less than page size, which 706 // should always be true if the function is not inlined. 707 708 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 709 #define NOINLINE 710 #else 711 #define NOINLINE __attribute__ ((noinline)) 712 #endif 713 714 static void _expand_stack_to(address bottom) NOINLINE; 715 716 static void _expand_stack_to(address bottom) { 717 address sp; 718 size_t size; 719 volatile char *p; 720 721 // Adjust bottom to point to the largest address within the same page, it 722 // gives us a one-page buffer if alloca() allocates slightly more memory. 723 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 724 bottom += os::Linux::page_size() - 1; 725 726 // sp might be slightly above current stack pointer; if that's the case, we 727 // will alloca() a little more space than necessary, which is OK. Don't use 728 // os::current_stack_pointer(), as its result can be slightly below current 729 // stack pointer, causing us to not alloca enough to reach "bottom". 730 sp = (address)&sp; 731 732 if (sp > bottom) { 733 size = sp - bottom; 734 p = (volatile char *)alloca(size); 735 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 736 p[0] = '\0'; 737 } 738 } 739 740 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 741 assert(t!=NULL, "just checking"); 742 assert(t->osthread()->expanding_stack(), "expand should be set"); 743 assert(t->stack_base() != NULL, "stack_base was not initialized"); 744 745 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 746 sigset_t mask_all, old_sigset; 747 sigfillset(&mask_all); 748 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 749 _expand_stack_to(addr); 750 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 751 return true; 752 } 753 return false; 754 } 755 756 ////////////////////////////////////////////////////////////////////////////// 757 // create new thread 758 759 static address highest_vm_reserved_address(); 760 761 // check if it's safe to start a new thread 762 static bool _thread_safety_check(Thread* thread) { 763 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) { 764 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat) 765 // Heap is mmap'ed at lower end of memory space. Thread stacks are 766 // allocated (MAP_FIXED) from high address space. Every thread stack 767 // occupies a fixed size slot (usually 2Mbytes, but user can change 768 // it to other values if they rebuild LinuxThreads). 769 // 770 // Problem with MAP_FIXED is that mmap() can still succeed even part of 771 // the memory region has already been mmap'ed. That means if we have too 772 // many threads and/or very large heap, eventually thread stack will 773 // collide with heap. 774 // 775 // Here we try to prevent heap/stack collision by comparing current 776 // stack bottom with the highest address that has been mmap'ed by JVM 777 // plus a safety margin for memory maps created by native code. 778 // 779 // This feature can be disabled by setting ThreadSafetyMargin to 0 780 // 781 if (ThreadSafetyMargin > 0) { 782 address stack_bottom = os::current_stack_base() - os::current_stack_size(); 783 784 // not safe if our stack extends below the safety margin 785 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address(); 786 } else { 787 return true; 788 } 789 } else { 790 // Floating stack LinuxThreads or NPTL: 791 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When 792 // there's not enough space left, pthread_create() will fail. If we come 793 // here, that means enough space has been reserved for stack. 794 return true; 795 } 796 } 797 798 // Thread start routine for all newly created threads 799 static void *java_start(Thread *thread) { 800 // Try to randomize the cache line index of hot stack frames. 801 // This helps when threads of the same stack traces evict each other's 802 // cache lines. The threads can be either from the same JVM instance, or 803 // from different JVM instances. The benefit is especially true for 804 // processors with hyperthreading technology. 805 static int counter = 0; 806 int pid = os::current_process_id(); 807 alloca(((pid ^ counter++) & 7) * 128); 808 809 ThreadLocalStorage::set_thread(thread); 810 811 OSThread* osthread = thread->osthread(); 812 Monitor* sync = osthread->startThread_lock(); 813 814 // non floating stack LinuxThreads needs extra check, see above 815 if (!_thread_safety_check(thread)) { 816 // notify parent thread 817 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 818 osthread->set_state(ZOMBIE); 819 sync->notify_all(); 820 return NULL; 821 } 822 823 // thread_id is kernel thread id (similar to Solaris LWP id) 824 osthread->set_thread_id(os::Linux::gettid()); 825 826 if (UseNUMA) { 827 int lgrp_id = os::numa_get_group_id(); 828 if (lgrp_id != -1) { 829 thread->set_lgrp_id(lgrp_id); 830 } 831 } 832 // initialize signal mask for this thread 833 os::Linux::hotspot_sigmask(thread); 834 835 // initialize floating point control register 836 os::Linux::init_thread_fpu_state(); 837 838 // handshaking with parent thread 839 { 840 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 841 842 // notify parent thread 843 osthread->set_state(INITIALIZED); 844 sync->notify_all(); 845 846 // wait until os::start_thread() 847 while (osthread->get_state() == INITIALIZED) { 848 sync->wait(Mutex::_no_safepoint_check_flag); 849 } 850 } 851 852 // call one more level start routine 853 thread->run(); 854 855 return 0; 856 } 857 858 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) { 859 assert(thread->osthread() == NULL, "caller responsible"); 860 861 // Allocate the OSThread object 862 OSThread* osthread = new OSThread(NULL, NULL); 863 if (osthread == NULL) { 864 return false; 865 } 866 867 // set the correct thread state 868 osthread->set_thread_type(thr_type); 869 870 // Initial state is ALLOCATED but not INITIALIZED 871 osthread->set_state(ALLOCATED); 872 873 thread->set_osthread(osthread); 874 875 // init thread attributes 876 pthread_attr_t attr; 877 pthread_attr_init(&attr); 878 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 879 880 // stack size 881 if (os::Linux::supports_variable_stack_size()) { 882 // calculate stack size if it's not specified by caller 883 if (stack_size == 0) { 884 stack_size = os::Linux::default_stack_size(thr_type); 885 886 switch (thr_type) { 887 case os::java_thread: 888 // Java threads use ThreadStackSize which default value can be changed with the flag -Xss 889 if (JavaThread::stack_size_at_create() > 0) stack_size = JavaThread::stack_size_at_create(); 890 break; 891 case os::compiler_thread: 892 if (CompilerThreadStackSize > 0) { 893 stack_size = (size_t)(CompilerThreadStackSize * K); 894 break; 895 } // else fall through: 896 // use VMThreadStackSize if CompilerThreadStackSize is not defined 897 case os::vm_thread: 898 case os::pgc_thread: 899 case os::cgc_thread: 900 case os::watcher_thread: 901 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 902 break; 903 } 904 } 905 906 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 907 pthread_attr_setstacksize(&attr, stack_size); 908 } else { 909 // let pthread_create() pick the default value. 910 } 911 912 // glibc guard page 913 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 914 915 ThreadState state; 916 917 { 918 // Serialize thread creation if we are running with fixed stack LinuxThreads 919 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack(); 920 if (lock) { 921 os::Linux::createThread_lock()->lock_without_safepoint_check(); 922 } 923 924 pthread_t tid; 925 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 926 927 pthread_attr_destroy(&attr); 928 929 if (ret != 0) { 930 if (PrintMiscellaneous && (Verbose || WizardMode)) { 931 perror("pthread_create()"); 932 } 933 // Need to clean up stuff we've allocated so far 934 thread->set_osthread(NULL); 935 delete osthread; 936 if (lock) os::Linux::createThread_lock()->unlock(); 937 return false; 938 } 939 940 // Store pthread info into the OSThread 941 osthread->set_pthread_id(tid); 942 943 // Wait until child thread is either initialized or aborted 944 { 945 Monitor* sync_with_child = osthread->startThread_lock(); 946 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 947 while ((state = osthread->get_state()) == ALLOCATED) { 948 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 949 } 950 } 951 952 if (lock) { 953 os::Linux::createThread_lock()->unlock(); 954 } 955 } 956 957 // Aborted due to thread limit being reached 958 if (state == ZOMBIE) { 959 thread->set_osthread(NULL); 960 delete osthread; 961 return false; 962 } 963 964 // The thread is returned suspended (in state INITIALIZED), 965 // and is started higher up in the call chain 966 assert(state == INITIALIZED, "race condition"); 967 return true; 968 } 969 970 ///////////////////////////////////////////////////////////////////////////// 971 // attach existing thread 972 973 // bootstrap the main thread 974 bool os::create_main_thread(JavaThread* thread) { 975 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 976 return create_attached_thread(thread); 977 } 978 979 bool os::create_attached_thread(JavaThread* thread) { 980 #ifdef ASSERT 981 thread->verify_not_published(); 982 #endif 983 984 // Allocate the OSThread object 985 OSThread* osthread = new OSThread(NULL, NULL); 986 987 if (osthread == NULL) { 988 return false; 989 } 990 991 // Store pthread info into the OSThread 992 osthread->set_thread_id(os::Linux::gettid()); 993 osthread->set_pthread_id(::pthread_self()); 994 995 // initialize floating point control register 996 os::Linux::init_thread_fpu_state(); 997 998 // Initial thread state is RUNNABLE 999 osthread->set_state(RUNNABLE); 1000 1001 thread->set_osthread(osthread); 1002 1003 if (UseNUMA) { 1004 int lgrp_id = os::numa_get_group_id(); 1005 if (lgrp_id != -1) { 1006 thread->set_lgrp_id(lgrp_id); 1007 } 1008 } 1009 1010 if (os::Linux::is_initial_thread()) { 1011 // If current thread is initial thread, its stack is mapped on demand, 1012 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 1013 // the entire stack region to avoid SEGV in stack banging. 1014 // It is also useful to get around the heap-stack-gap problem on SuSE 1015 // kernel (see 4821821 for details). We first expand stack to the top 1016 // of yellow zone, then enable stack yellow zone (order is significant, 1017 // enabling yellow zone first will crash JVM on SuSE Linux), so there 1018 // is no gap between the last two virtual memory regions. 1019 1020 JavaThread *jt = (JavaThread *)thread; 1021 address addr = jt->stack_yellow_zone_base(); 1022 assert(addr != NULL, "initialization problem?"); 1023 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 1024 1025 osthread->set_expanding_stack(); 1026 os::Linux::manually_expand_stack(jt, addr); 1027 osthread->clear_expanding_stack(); 1028 } 1029 1030 // initialize signal mask for this thread 1031 // and save the caller's signal mask 1032 os::Linux::hotspot_sigmask(thread); 1033 1034 return true; 1035 } 1036 1037 void os::pd_start_thread(Thread* thread) { 1038 OSThread * osthread = thread->osthread(); 1039 assert(osthread->get_state() != INITIALIZED, "just checking"); 1040 Monitor* sync_with_child = osthread->startThread_lock(); 1041 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 1042 sync_with_child->notify(); 1043 } 1044 1045 // Free Linux resources related to the OSThread 1046 void os::free_thread(OSThread* osthread) { 1047 assert(osthread != NULL, "osthread not set"); 1048 1049 if (Thread::current()->osthread() == osthread) { 1050 // Restore caller's signal mask 1051 sigset_t sigmask = osthread->caller_sigmask(); 1052 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1053 } 1054 1055 delete osthread; 1056 } 1057 1058 ////////////////////////////////////////////////////////////////////////////// 1059 // thread local storage 1060 1061 int os::allocate_thread_local_storage() { 1062 pthread_key_t key; 1063 int rslt = pthread_key_create(&key, NULL); 1064 assert(rslt == 0, "cannot allocate thread local storage"); 1065 return (int)key; 1066 } 1067 1068 // Note: This is currently not used by VM, as we don't destroy TLS key 1069 // on VM exit. 1070 void os::free_thread_local_storage(int index) { 1071 int rslt = pthread_key_delete((pthread_key_t)index); 1072 assert(rslt == 0, "invalid index"); 1073 } 1074 1075 void os::thread_local_storage_at_put(int index, void* value) { 1076 int rslt = pthread_setspecific((pthread_key_t)index, value); 1077 assert(rslt == 0, "pthread_setspecific failed"); 1078 } 1079 1080 extern "C" Thread* get_thread() { 1081 return ThreadLocalStorage::thread(); 1082 } 1083 1084 ////////////////////////////////////////////////////////////////////////////// 1085 // initial thread 1086 1087 // Check if current thread is the initial thread, similar to Solaris thr_main. 1088 bool os::Linux::is_initial_thread(void) { 1089 char dummy; 1090 // If called before init complete, thread stack bottom will be null. 1091 // Can be called if fatal error occurs before initialization. 1092 if (initial_thread_stack_bottom() == NULL) return false; 1093 assert(initial_thread_stack_bottom() != NULL && 1094 initial_thread_stack_size() != 0, 1095 "os::init did not locate initial thread's stack region"); 1096 if ((address)&dummy >= initial_thread_stack_bottom() && 1097 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) 1098 return true; 1099 else return false; 1100 } 1101 1102 // Find the virtual memory area that contains addr 1103 static bool find_vma(address addr, address* vma_low, address* vma_high) { 1104 FILE *fp = fopen("/proc/self/maps", "r"); 1105 if (fp) { 1106 address low, high; 1107 while (!feof(fp)) { 1108 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1109 if (low <= addr && addr < high) { 1110 if (vma_low) *vma_low = low; 1111 if (vma_high) *vma_high = high; 1112 fclose (fp); 1113 return true; 1114 } 1115 } 1116 for (;;) { 1117 int ch = fgetc(fp); 1118 if (ch == EOF || ch == (int)'\n') break; 1119 } 1120 } 1121 fclose(fp); 1122 } 1123 return false; 1124 } 1125 1126 // Locate initial thread stack. This special handling of initial thread stack 1127 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 1128 // bogus value for initial thread. 1129 void os::Linux::capture_initial_stack(size_t max_size) { 1130 // stack size is the easy part, get it from RLIMIT_STACK 1131 size_t stack_size; 1132 struct rlimit rlim; 1133 getrlimit(RLIMIT_STACK, &rlim); 1134 stack_size = rlim.rlim_cur; 1135 1136 // 6308388: a bug in ld.so will relocate its own .data section to the 1137 // lower end of primordial stack; reduce ulimit -s value a little bit 1138 // so we won't install guard page on ld.so's data section. 1139 stack_size -= 2 * page_size(); 1140 1141 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 1142 // 7.1, in both cases we will get 2G in return value. 1143 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 1144 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 1145 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 1146 // in case other parts in glibc still assumes 2M max stack size. 1147 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 1148 #ifndef IA64 1149 if (stack_size > 2 * K * K) stack_size = 2 * K * K; 1150 #else 1151 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 1152 if (stack_size > 4 * K * K) stack_size = 4 * K * K; 1153 #endif 1154 1155 // Try to figure out where the stack base (top) is. This is harder. 1156 // 1157 // When an application is started, glibc saves the initial stack pointer in 1158 // a global variable "__libc_stack_end", which is then used by system 1159 // libraries. __libc_stack_end should be pretty close to stack top. The 1160 // variable is available since the very early days. However, because it is 1161 // a private interface, it could disappear in the future. 1162 // 1163 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1164 // to __libc_stack_end, it is very close to stack top, but isn't the real 1165 // stack top. Note that /proc may not exist if VM is running as a chroot 1166 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1167 // /proc/<pid>/stat could change in the future (though unlikely). 1168 // 1169 // We try __libc_stack_end first. If that doesn't work, look for 1170 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1171 // as a hint, which should work well in most cases. 1172 1173 uintptr_t stack_start; 1174 1175 // try __libc_stack_end first 1176 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1177 if (p && *p) { 1178 stack_start = *p; 1179 } else { 1180 // see if we can get the start_stack field from /proc/self/stat 1181 FILE *fp; 1182 int pid; 1183 char state; 1184 int ppid; 1185 int pgrp; 1186 int session; 1187 int nr; 1188 int tpgrp; 1189 unsigned long flags; 1190 unsigned long minflt; 1191 unsigned long cminflt; 1192 unsigned long majflt; 1193 unsigned long cmajflt; 1194 unsigned long utime; 1195 unsigned long stime; 1196 long cutime; 1197 long cstime; 1198 long prio; 1199 long nice; 1200 long junk; 1201 long it_real; 1202 uintptr_t start; 1203 uintptr_t vsize; 1204 intptr_t rss; 1205 uintptr_t rsslim; 1206 uintptr_t scodes; 1207 uintptr_t ecode; 1208 int i; 1209 1210 // Figure what the primordial thread stack base is. Code is inspired 1211 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1212 // followed by command name surrounded by parentheses, state, etc. 1213 char stat[2048]; 1214 int statlen; 1215 1216 fp = fopen("/proc/self/stat", "r"); 1217 if (fp) { 1218 statlen = fread(stat, 1, 2047, fp); 1219 stat[statlen] = '\0'; 1220 fclose(fp); 1221 1222 // Skip pid and the command string. Note that we could be dealing with 1223 // weird command names, e.g. user could decide to rename java launcher 1224 // to "java 1.4.2 :)", then the stat file would look like 1225 // 1234 (java 1.4.2 :)) R ... ... 1226 // We don't really need to know the command string, just find the last 1227 // occurrence of ")" and then start parsing from there. See bug 4726580. 1228 char * s = strrchr(stat, ')'); 1229 1230 i = 0; 1231 if (s) { 1232 // Skip blank chars 1233 do s++; while (isspace(*s)); 1234 1235 #define _UFM UINTX_FORMAT 1236 #define _DFM INTX_FORMAT 1237 1238 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */ 1239 /* 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 */ 1240 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM, 1241 &state, /* 3 %c */ 1242 &ppid, /* 4 %d */ 1243 &pgrp, /* 5 %d */ 1244 &session, /* 6 %d */ 1245 &nr, /* 7 %d */ 1246 &tpgrp, /* 8 %d */ 1247 &flags, /* 9 %lu */ 1248 &minflt, /* 10 %lu */ 1249 &cminflt, /* 11 %lu */ 1250 &majflt, /* 12 %lu */ 1251 &cmajflt, /* 13 %lu */ 1252 &utime, /* 14 %lu */ 1253 &stime, /* 15 %lu */ 1254 &cutime, /* 16 %ld */ 1255 &cstime, /* 17 %ld */ 1256 &prio, /* 18 %ld */ 1257 &nice, /* 19 %ld */ 1258 &junk, /* 20 %ld */ 1259 &it_real, /* 21 %ld */ 1260 &start, /* 22 UINTX_FORMAT */ 1261 &vsize, /* 23 UINTX_FORMAT */ 1262 &rss, /* 24 INTX_FORMAT */ 1263 &rsslim, /* 25 UINTX_FORMAT */ 1264 &scodes, /* 26 UINTX_FORMAT */ 1265 &ecode, /* 27 UINTX_FORMAT */ 1266 &stack_start); /* 28 UINTX_FORMAT */ 1267 } 1268 1269 #undef _UFM 1270 #undef _DFM 1271 1272 if (i != 28 - 2) { 1273 assert(false, "Bad conversion from /proc/self/stat"); 1274 // product mode - assume we are the initial thread, good luck in the 1275 // embedded case. 1276 warning("Can't detect initial thread stack location - bad conversion"); 1277 stack_start = (uintptr_t) &rlim; 1278 } 1279 } else { 1280 // For some reason we can't open /proc/self/stat (for example, running on 1281 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1282 // most cases, so don't abort: 1283 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1284 stack_start = (uintptr_t) &rlim; 1285 } 1286 } 1287 1288 // Now we have a pointer (stack_start) very close to the stack top, the 1289 // next thing to do is to figure out the exact location of stack top. We 1290 // can find out the virtual memory area that contains stack_start by 1291 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1292 // and its upper limit is the real stack top. (again, this would fail if 1293 // running inside chroot, because /proc may not exist.) 1294 1295 uintptr_t stack_top; 1296 address low, high; 1297 if (find_vma((address)stack_start, &low, &high)) { 1298 // success, "high" is the true stack top. (ignore "low", because initial 1299 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1300 stack_top = (uintptr_t)high; 1301 } else { 1302 // failed, likely because /proc/self/maps does not exist 1303 warning("Can't detect initial thread stack location - find_vma failed"); 1304 // best effort: stack_start is normally within a few pages below the real 1305 // stack top, use it as stack top, and reduce stack size so we won't put 1306 // guard page outside stack. 1307 stack_top = stack_start; 1308 stack_size -= 16 * page_size(); 1309 } 1310 1311 // stack_top could be partially down the page so align it 1312 stack_top = align_size_up(stack_top, page_size()); 1313 1314 if (max_size && stack_size > max_size) { 1315 _initial_thread_stack_size = max_size; 1316 } else { 1317 _initial_thread_stack_size = stack_size; 1318 } 1319 1320 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1321 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1322 } 1323 1324 //////////////////////////////////////////////////////////////////////////////// 1325 // time support 1326 1327 // Time since start-up in seconds to a fine granularity. 1328 // Used by VMSelfDestructTimer and the MemProfiler. 1329 double os::elapsedTime() { 1330 1331 return (double)(os::elapsed_counter()) * 0.000001; 1332 } 1333 1334 jlong os::elapsed_counter() { 1335 timeval time; 1336 int status = gettimeofday(&time, NULL); 1337 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count; 1338 } 1339 1340 jlong os::elapsed_frequency() { 1341 return (1000 * 1000); 1342 } 1343 1344 // For now, we say that linux does not support vtime. I have no idea 1345 // whether it can actually be made to (DLD, 9/13/05). 1346 1347 bool os::supports_vtime() { return false; } 1348 bool os::enable_vtime() { return false; } 1349 bool os::vtime_enabled() { return false; } 1350 double os::elapsedVTime() { 1351 // better than nothing, but not much 1352 return elapsedTime(); 1353 } 1354 1355 jlong os::javaTimeMillis() { 1356 timeval time; 1357 int status = gettimeofday(&time, NULL); 1358 assert(status != -1, "linux error"); 1359 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1360 } 1361 1362 #ifndef CLOCK_MONOTONIC 1363 #define CLOCK_MONOTONIC (1) 1364 #endif 1365 1366 void os::Linux::clock_init() { 1367 // we do dlopen's in this particular order due to bug in linux 1368 // dynamical loader (see 6348968) leading to crash on exit 1369 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1370 if (handle == NULL) { 1371 handle = dlopen("librt.so", RTLD_LAZY); 1372 } 1373 1374 if (handle) { 1375 int (*clock_getres_func)(clockid_t, struct timespec*) = 1376 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1377 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1378 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1379 if (clock_getres_func && clock_gettime_func) { 1380 // See if monotonic clock is supported by the kernel. Note that some 1381 // early implementations simply return kernel jiffies (updated every 1382 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1383 // for nano time (though the monotonic property is still nice to have). 1384 // It's fixed in newer kernels, however clock_getres() still returns 1385 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1386 // resolution for now. Hopefully as people move to new kernels, this 1387 // won't be a problem. 1388 struct timespec res; 1389 struct timespec tp; 1390 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1391 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1392 // yes, monotonic clock is supported 1393 _clock_gettime = clock_gettime_func; 1394 } else { 1395 // close librt if there is no monotonic clock 1396 dlclose(handle); 1397 } 1398 } 1399 } 1400 } 1401 1402 #ifndef SYS_clock_getres 1403 1404 #if defined(IA32) || defined(AMD64) 1405 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1406 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1407 #else 1408 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1409 #define sys_clock_getres(x,y) -1 1410 #endif 1411 1412 #else 1413 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1414 #endif 1415 1416 void os::Linux::fast_thread_clock_init() { 1417 if (!UseLinuxPosixThreadCPUClocks) { 1418 return; 1419 } 1420 clockid_t clockid; 1421 struct timespec tp; 1422 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1423 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1424 1425 // Switch to using fast clocks for thread cpu time if 1426 // the sys_clock_getres() returns 0 error code. 1427 // Note, that some kernels may support the current thread 1428 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1429 // returned by the pthread_getcpuclockid(). 1430 // If the fast Posix clocks are supported then the sys_clock_getres() 1431 // must return at least tp.tv_sec == 0 which means a resolution 1432 // better than 1 sec. This is extra check for reliability. 1433 1434 if(pthread_getcpuclockid_func && 1435 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1436 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1437 1438 _supports_fast_thread_cpu_time = true; 1439 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1440 } 1441 } 1442 1443 jlong os::javaTimeNanos() { 1444 if (Linux::supports_monotonic_clock()) { 1445 struct timespec tp; 1446 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1447 assert(status == 0, "gettime error"); 1448 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1449 return result; 1450 } else { 1451 timeval time; 1452 int status = gettimeofday(&time, NULL); 1453 assert(status != -1, "linux error"); 1454 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1455 return 1000 * usecs; 1456 } 1457 } 1458 1459 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1460 if (Linux::supports_monotonic_clock()) { 1461 info_ptr->max_value = ALL_64_BITS; 1462 1463 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1464 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1465 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1466 } else { 1467 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1468 info_ptr->max_value = ALL_64_BITS; 1469 1470 // gettimeofday is a real time clock so it skips 1471 info_ptr->may_skip_backward = true; 1472 info_ptr->may_skip_forward = true; 1473 } 1474 1475 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1476 } 1477 1478 // Return the real, user, and system times in seconds from an 1479 // arbitrary fixed point in the past. 1480 bool os::getTimesSecs(double* process_real_time, 1481 double* process_user_time, 1482 double* process_system_time) { 1483 struct tms ticks; 1484 clock_t real_ticks = times(&ticks); 1485 1486 if (real_ticks == (clock_t) (-1)) { 1487 return false; 1488 } else { 1489 double ticks_per_second = (double) clock_tics_per_sec; 1490 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1491 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1492 *process_real_time = ((double) real_ticks) / ticks_per_second; 1493 1494 return true; 1495 } 1496 } 1497 1498 1499 char * os::local_time_string(char *buf, size_t buflen) { 1500 struct tm t; 1501 time_t long_time; 1502 time(&long_time); 1503 localtime_r(&long_time, &t); 1504 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1505 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1506 t.tm_hour, t.tm_min, t.tm_sec); 1507 return buf; 1508 } 1509 1510 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1511 return localtime_r(clock, res); 1512 } 1513 1514 //////////////////////////////////////////////////////////////////////////////// 1515 // runtime exit support 1516 1517 // Note: os::shutdown() might be called very early during initialization, or 1518 // called from signal handler. Before adding something to os::shutdown(), make 1519 // sure it is async-safe and can handle partially initialized VM. 1520 void os::shutdown() { 1521 1522 // allow PerfMemory to attempt cleanup of any persistent resources 1523 perfMemory_exit(); 1524 1525 // needs to remove object in file system 1526 AttachListener::abort(); 1527 1528 // flush buffered output, finish log files 1529 ostream_abort(); 1530 1531 // Check for abort hook 1532 abort_hook_t abort_hook = Arguments::abort_hook(); 1533 if (abort_hook != NULL) { 1534 abort_hook(); 1535 } 1536 1537 } 1538 1539 // Note: os::abort() might be called very early during initialization, or 1540 // called from signal handler. Before adding something to os::abort(), make 1541 // sure it is async-safe and can handle partially initialized VM. 1542 void os::abort(bool dump_core) { 1543 os::shutdown(); 1544 if (dump_core) { 1545 #ifndef PRODUCT 1546 fdStream out(defaultStream::output_fd()); 1547 out.print_raw("Current thread is "); 1548 char buf[16]; 1549 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1550 out.print_raw_cr(buf); 1551 out.print_raw_cr("Dumping core ..."); 1552 #endif 1553 ::abort(); // dump core 1554 } 1555 1556 ::exit(1); 1557 } 1558 1559 // Die immediately, no exit hook, no abort hook, no cleanup. 1560 void os::die() { 1561 // _exit() on LinuxThreads only kills current thread 1562 ::abort(); 1563 } 1564 1565 // unused on linux for now. 1566 void os::set_error_file(const char *logfile) {} 1567 1568 intx os::current_thread_id() { return (intx)pthread_self(); } 1569 int os::current_process_id() { 1570 1571 // Under the old linux thread library, linux gives each thread 1572 // its own process id. Because of this each thread will return 1573 // a different pid if this method were to return the result 1574 // of getpid(2). Linux provides no api that returns the pid 1575 // of the launcher thread for the vm. This implementation 1576 // returns a unique pid, the pid of the launcher thread 1577 // that starts the vm 'process'. 1578 1579 // Under the NPTL, getpid() returns the same pid as the 1580 // launcher thread rather than a unique pid per thread. 1581 // Use gettid() if you want the old pre NPTL behaviour. 1582 1583 // if you are looking for the result of a call to getpid() that 1584 // returns a unique pid for the calling thread, then look at the 1585 // OSThread::thread_id() method in osThread_linux.hpp file 1586 1587 return (int)(_initial_pid ? _initial_pid : getpid()); 1588 } 1589 1590 // DLL functions 1591 1592 const char* os::dll_file_extension() { return ".so"; } 1593 1594 const char* os::get_temp_directory() { 1595 const char *prop = Arguments::get_property("java.io.tmpdir"); 1596 return prop == NULL ? "/tmp" : prop; 1597 } 1598 1599 static bool file_exists(const char* filename) { 1600 struct stat statbuf; 1601 if (filename == NULL || strlen(filename) == 0) { 1602 return false; 1603 } 1604 return os::stat(filename, &statbuf) == 0; 1605 } 1606 1607 void os::dll_build_name(char* buffer, size_t buflen, 1608 const char* pname, const char* fname) { 1609 // Copied from libhpi 1610 const size_t pnamelen = pname ? strlen(pname) : 0; 1611 1612 // Quietly truncate on buffer overflow. Should be an error. 1613 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1614 *buffer = '\0'; 1615 return; 1616 } 1617 1618 if (pnamelen == 0) { 1619 snprintf(buffer, buflen, "lib%s.so", fname); 1620 } else if (strchr(pname, *os::path_separator()) != NULL) { 1621 int n; 1622 char** pelements = split_path(pname, &n); 1623 for (int i = 0 ; i < n ; i++) { 1624 // Really shouldn't be NULL, but check can't hurt 1625 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1626 continue; // skip the empty path values 1627 } 1628 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1629 if (file_exists(buffer)) { 1630 break; 1631 } 1632 } 1633 // release the storage 1634 for (int i = 0 ; i < n ; i++) { 1635 if (pelements[i] != NULL) { 1636 FREE_C_HEAP_ARRAY(char, pelements[i]); 1637 } 1638 } 1639 if (pelements != NULL) { 1640 FREE_C_HEAP_ARRAY(char*, pelements); 1641 } 1642 } else { 1643 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1644 } 1645 } 1646 1647 const char* os::get_current_directory(char *buf, int buflen) { 1648 return getcwd(buf, buflen); 1649 } 1650 1651 // check if addr is inside libjvm[_g].so 1652 bool os::address_is_in_vm(address addr) { 1653 static address libjvm_base_addr; 1654 Dl_info dlinfo; 1655 1656 if (libjvm_base_addr == NULL) { 1657 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo); 1658 libjvm_base_addr = (address)dlinfo.dli_fbase; 1659 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1660 } 1661 1662 if (dladdr((void *)addr, &dlinfo)) { 1663 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1664 } 1665 1666 return false; 1667 } 1668 1669 bool os::dll_address_to_function_name(address addr, char *buf, 1670 int buflen, int *offset) { 1671 Dl_info dlinfo; 1672 1673 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) { 1674 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1675 if (offset) *offset = addr - (address)dlinfo.dli_saddr; 1676 return true; 1677 } else { 1678 if (buf) buf[0] = '\0'; 1679 if (offset) *offset = -1; 1680 return false; 1681 } 1682 } 1683 1684 struct _address_to_library_name { 1685 address addr; // input : memory address 1686 size_t buflen; // size of fname 1687 char* fname; // output: library name 1688 address base; // library base addr 1689 }; 1690 1691 static int address_to_library_name_callback(struct dl_phdr_info *info, 1692 size_t size, void *data) { 1693 int i; 1694 bool found = false; 1695 address libbase = NULL; 1696 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1697 1698 // iterate through all loadable segments 1699 for (i = 0; i < info->dlpi_phnum; i++) { 1700 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1701 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1702 // base address of a library is the lowest address of its loaded 1703 // segments. 1704 if (libbase == NULL || libbase > segbase) { 1705 libbase = segbase; 1706 } 1707 // see if 'addr' is within current segment 1708 if (segbase <= d->addr && 1709 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1710 found = true; 1711 } 1712 } 1713 } 1714 1715 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1716 // so dll_address_to_library_name() can fall through to use dladdr() which 1717 // can figure out executable name from argv[0]. 1718 if (found && info->dlpi_name && info->dlpi_name[0]) { 1719 d->base = libbase; 1720 if (d->fname) { 1721 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1722 } 1723 return 1; 1724 } 1725 return 0; 1726 } 1727 1728 bool os::dll_address_to_library_name(address addr, char* buf, 1729 int buflen, int* offset) { 1730 Dl_info dlinfo; 1731 struct _address_to_library_name data; 1732 1733 // There is a bug in old glibc dladdr() implementation that it could resolve 1734 // to wrong library name if the .so file has a base address != NULL. Here 1735 // we iterate through the program headers of all loaded libraries to find 1736 // out which library 'addr' really belongs to. This workaround can be 1737 // removed once the minimum requirement for glibc is moved to 2.3.x. 1738 data.addr = addr; 1739 data.fname = buf; 1740 data.buflen = buflen; 1741 data.base = NULL; 1742 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1743 1744 if (rslt) { 1745 // buf already contains library name 1746 if (offset) *offset = addr - data.base; 1747 return true; 1748 } else if (dladdr((void*)addr, &dlinfo)){ 1749 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1750 if (offset) *offset = addr - (address)dlinfo.dli_fbase; 1751 return true; 1752 } else { 1753 if (buf) buf[0] = '\0'; 1754 if (offset) *offset = -1; 1755 return false; 1756 } 1757 } 1758 1759 // Loads .dll/.so and 1760 // in case of error it checks if .dll/.so was built for the 1761 // same architecture as Hotspot is running on 1762 1763 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) 1764 { 1765 void * result= ::dlopen(filename, RTLD_LAZY); 1766 if (result != NULL) { 1767 // Successful loading 1768 return result; 1769 } 1770 1771 Elf32_Ehdr elf_head; 1772 1773 // Read system error message into ebuf 1774 // It may or may not be overwritten below 1775 ::strncpy(ebuf, ::dlerror(), ebuflen-1); 1776 ebuf[ebuflen-1]='\0'; 1777 int diag_msg_max_length=ebuflen-strlen(ebuf); 1778 char* diag_msg_buf=ebuf+strlen(ebuf); 1779 1780 if (diag_msg_max_length==0) { 1781 // No more space in ebuf for additional diagnostics message 1782 return NULL; 1783 } 1784 1785 1786 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1787 1788 if (file_descriptor < 0) { 1789 // Can't open library, report dlerror() message 1790 return NULL; 1791 } 1792 1793 bool failed_to_read_elf_head= 1794 (sizeof(elf_head)!= 1795 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ; 1796 1797 ::close(file_descriptor); 1798 if (failed_to_read_elf_head) { 1799 // file i/o error - report dlerror() msg 1800 return NULL; 1801 } 1802 1803 typedef struct { 1804 Elf32_Half code; // Actual value as defined in elf.h 1805 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1806 char elf_class; // 32 or 64 bit 1807 char endianess; // MSB or LSB 1808 char* name; // String representation 1809 } arch_t; 1810 1811 #ifndef EM_486 1812 #define EM_486 6 /* Intel 80486 */ 1813 #endif 1814 1815 static const arch_t arch_array[]={ 1816 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1817 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1818 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1819 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1820 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1821 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1822 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1823 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1824 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1825 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1826 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1827 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1828 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1829 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1830 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1831 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"} 1832 }; 1833 1834 #if (defined IA32) 1835 static Elf32_Half running_arch_code=EM_386; 1836 #elif (defined AMD64) 1837 static Elf32_Half running_arch_code=EM_X86_64; 1838 #elif (defined IA64) 1839 static Elf32_Half running_arch_code=EM_IA_64; 1840 #elif (defined __sparc) && (defined _LP64) 1841 static Elf32_Half running_arch_code=EM_SPARCV9; 1842 #elif (defined __sparc) && (!defined _LP64) 1843 static Elf32_Half running_arch_code=EM_SPARC; 1844 #elif (defined __powerpc64__) 1845 static Elf32_Half running_arch_code=EM_PPC64; 1846 #elif (defined __powerpc__) 1847 static Elf32_Half running_arch_code=EM_PPC; 1848 #elif (defined ARM) 1849 static Elf32_Half running_arch_code=EM_ARM; 1850 #elif (defined S390) 1851 static Elf32_Half running_arch_code=EM_S390; 1852 #elif (defined ALPHA) 1853 static Elf32_Half running_arch_code=EM_ALPHA; 1854 #elif (defined MIPSEL) 1855 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1856 #elif (defined PARISC) 1857 static Elf32_Half running_arch_code=EM_PARISC; 1858 #elif (defined MIPS) 1859 static Elf32_Half running_arch_code=EM_MIPS; 1860 #elif (defined M68K) 1861 static Elf32_Half running_arch_code=EM_68K; 1862 #else 1863 #error Method os::dll_load requires that one of following is defined:\ 1864 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K 1865 #endif 1866 1867 // Identify compatability class for VM's architecture and library's architecture 1868 // Obtain string descriptions for architectures 1869 1870 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1871 int running_arch_index=-1; 1872 1873 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) { 1874 if (running_arch_code == arch_array[i].code) { 1875 running_arch_index = i; 1876 } 1877 if (lib_arch.code == arch_array[i].code) { 1878 lib_arch.compat_class = arch_array[i].compat_class; 1879 lib_arch.name = arch_array[i].name; 1880 } 1881 } 1882 1883 assert(running_arch_index != -1, 1884 "Didn't find running architecture code (running_arch_code) in arch_array"); 1885 if (running_arch_index == -1) { 1886 // Even though running architecture detection failed 1887 // we may still continue with reporting dlerror() message 1888 return NULL; 1889 } 1890 1891 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1892 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1893 return NULL; 1894 } 1895 1896 #ifndef S390 1897 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1898 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1899 return NULL; 1900 } 1901 #endif // !S390 1902 1903 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1904 if ( lib_arch.name!=NULL ) { 1905 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1906 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1907 lib_arch.name, arch_array[running_arch_index].name); 1908 } else { 1909 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1910 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1911 lib_arch.code, 1912 arch_array[running_arch_index].name); 1913 } 1914 } 1915 1916 return NULL; 1917 } 1918 1919 /* 1920 * glibc-2.0 libdl is not MT safe. If you are building with any glibc, 1921 * chances are you might want to run the generated bits against glibc-2.0 1922 * libdl.so, so always use locking for any version of glibc. 1923 */ 1924 void* os::dll_lookup(void* handle, const char* name) { 1925 pthread_mutex_lock(&dl_mutex); 1926 void* res = dlsym(handle, name); 1927 pthread_mutex_unlock(&dl_mutex); 1928 return res; 1929 } 1930 1931 1932 bool _print_ascii_file(const char* filename, outputStream* st) { 1933 int fd = open(filename, O_RDONLY); 1934 if (fd == -1) { 1935 return false; 1936 } 1937 1938 char buf[32]; 1939 int bytes; 1940 while ((bytes = read(fd, buf, sizeof(buf))) > 0) { 1941 st->print_raw(buf, bytes); 1942 } 1943 1944 close(fd); 1945 1946 return true; 1947 } 1948 1949 void os::print_dll_info(outputStream *st) { 1950 st->print_cr("Dynamic libraries:"); 1951 1952 char fname[32]; 1953 pid_t pid = os::Linux::gettid(); 1954 1955 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1956 1957 if (!_print_ascii_file(fname, st)) { 1958 st->print("Can not get library information for pid = %d\n", pid); 1959 } 1960 } 1961 1962 1963 void os::print_os_info(outputStream* st) { 1964 st->print("OS:"); 1965 1966 // Try to identify popular distros. 1967 // Most Linux distributions have /etc/XXX-release file, which contains 1968 // the OS version string. Some have more than one /etc/XXX-release file 1969 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.), 1970 // so the order is important. 1971 if (!_print_ascii_file("/etc/mandrake-release", st) && 1972 !_print_ascii_file("/etc/sun-release", st) && 1973 !_print_ascii_file("/etc/redhat-release", st) && 1974 !_print_ascii_file("/etc/SuSE-release", st) && 1975 !_print_ascii_file("/etc/turbolinux-release", st) && 1976 !_print_ascii_file("/etc/gentoo-release", st) && 1977 !_print_ascii_file("/etc/debian_version", st) && 1978 !_print_ascii_file("/etc/ltib-release", st) && 1979 !_print_ascii_file("/etc/angstrom-version", st)) { 1980 st->print("Linux"); 1981 } 1982 st->cr(); 1983 1984 // kernel 1985 st->print("uname:"); 1986 struct utsname name; 1987 uname(&name); 1988 st->print(name.sysname); st->print(" "); 1989 st->print(name.release); st->print(" "); 1990 st->print(name.version); st->print(" "); 1991 st->print(name.machine); 1992 st->cr(); 1993 1994 // Print warning if unsafe chroot environment detected 1995 if (unsafe_chroot_detected) { 1996 st->print("WARNING!! "); 1997 st->print_cr(unstable_chroot_error); 1998 } 1999 2000 // libc, pthread 2001 st->print("libc:"); 2002 st->print(os::Linux::glibc_version()); st->print(" "); 2003 st->print(os::Linux::libpthread_version()); st->print(" "); 2004 if (os::Linux::is_LinuxThreads()) { 2005 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed"); 2006 } 2007 st->cr(); 2008 2009 // rlimit 2010 st->print("rlimit:"); 2011 struct rlimit rlim; 2012 2013 st->print(" STACK "); 2014 getrlimit(RLIMIT_STACK, &rlim); 2015 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2016 else st->print("%uk", rlim.rlim_cur >> 10); 2017 2018 st->print(", CORE "); 2019 getrlimit(RLIMIT_CORE, &rlim); 2020 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2021 else st->print("%uk", rlim.rlim_cur >> 10); 2022 2023 st->print(", NPROC "); 2024 getrlimit(RLIMIT_NPROC, &rlim); 2025 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2026 else st->print("%d", rlim.rlim_cur); 2027 2028 st->print(", NOFILE "); 2029 getrlimit(RLIMIT_NOFILE, &rlim); 2030 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2031 else st->print("%d", rlim.rlim_cur); 2032 2033 st->print(", AS "); 2034 getrlimit(RLIMIT_AS, &rlim); 2035 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2036 else st->print("%uk", rlim.rlim_cur >> 10); 2037 st->cr(); 2038 2039 // load average 2040 st->print("load average:"); 2041 double loadavg[3]; 2042 os::loadavg(loadavg, 3); 2043 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]); 2044 st->cr(); 2045 2046 // meminfo 2047 st->print("\n/proc/meminfo:\n"); 2048 _print_ascii_file("/proc/meminfo", st); 2049 st->cr(); 2050 } 2051 2052 void os::print_memory_info(outputStream* st) { 2053 2054 st->print("Memory:"); 2055 st->print(" %dk page", os::vm_page_size()>>10); 2056 2057 // values in struct sysinfo are "unsigned long" 2058 struct sysinfo si; 2059 sysinfo(&si); 2060 2061 st->print(", physical " UINT64_FORMAT "k", 2062 os::physical_memory() >> 10); 2063 st->print("(" UINT64_FORMAT "k free)", 2064 os::available_memory() >> 10); 2065 st->print(", swap " UINT64_FORMAT "k", 2066 ((jlong)si.totalswap * si.mem_unit) >> 10); 2067 st->print("(" UINT64_FORMAT "k free)", 2068 ((jlong)si.freeswap * si.mem_unit) >> 10); 2069 st->cr(); 2070 } 2071 2072 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific 2073 // but they're the same for all the linux arch that we support 2074 // and they're the same for solaris but there's no common place to put this. 2075 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR", 2076 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG", 2077 "ILL_COPROC", "ILL_BADSTK" }; 2078 2079 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV", 2080 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES", 2081 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" }; 2082 2083 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" }; 2084 2085 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" }; 2086 2087 void os::print_siginfo(outputStream* st, void* siginfo) { 2088 st->print("siginfo:"); 2089 2090 const int buflen = 100; 2091 char buf[buflen]; 2092 siginfo_t *si = (siginfo_t*)siginfo; 2093 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen)); 2094 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) { 2095 st->print("si_errno=%s", buf); 2096 } else { 2097 st->print("si_errno=%d", si->si_errno); 2098 } 2099 const int c = si->si_code; 2100 assert(c > 0, "unexpected si_code"); 2101 switch (si->si_signo) { 2102 case SIGILL: 2103 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]); 2104 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2105 break; 2106 case SIGFPE: 2107 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]); 2108 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2109 break; 2110 case SIGSEGV: 2111 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]); 2112 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2113 break; 2114 case SIGBUS: 2115 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]); 2116 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2117 break; 2118 default: 2119 st->print(", si_code=%d", si->si_code); 2120 // no si_addr 2121 } 2122 2123 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2124 UseSharedSpaces) { 2125 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2126 if (mapinfo->is_in_shared_space(si->si_addr)) { 2127 st->print("\n\nError accessing class data sharing archive." \ 2128 " Mapped file inaccessible during execution, " \ 2129 " possible disk/network problem."); 2130 } 2131 } 2132 st->cr(); 2133 } 2134 2135 2136 static void print_signal_handler(outputStream* st, int sig, 2137 char* buf, size_t buflen); 2138 2139 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2140 st->print_cr("Signal Handlers:"); 2141 print_signal_handler(st, SIGSEGV, buf, buflen); 2142 print_signal_handler(st, SIGBUS , buf, buflen); 2143 print_signal_handler(st, SIGFPE , buf, buflen); 2144 print_signal_handler(st, SIGPIPE, buf, buflen); 2145 print_signal_handler(st, SIGXFSZ, buf, buflen); 2146 print_signal_handler(st, SIGILL , buf, buflen); 2147 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2148 print_signal_handler(st, SR_signum, buf, buflen); 2149 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2150 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2151 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2152 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2153 } 2154 2155 static char saved_jvm_path[MAXPATHLEN] = {0}; 2156 2157 // Find the full path to the current module, libjvm.so or libjvm_g.so 2158 void os::jvm_path(char *buf, jint buflen) { 2159 // Error checking. 2160 if (buflen < MAXPATHLEN) { 2161 assert(false, "must use a large-enough buffer"); 2162 buf[0] = '\0'; 2163 return; 2164 } 2165 // Lazy resolve the path to current module. 2166 if (saved_jvm_path[0] != 0) { 2167 strcpy(buf, saved_jvm_path); 2168 return; 2169 } 2170 2171 char dli_fname[MAXPATHLEN]; 2172 bool ret = dll_address_to_library_name( 2173 CAST_FROM_FN_PTR(address, os::jvm_path), 2174 dli_fname, sizeof(dli_fname), NULL); 2175 assert(ret != 0, "cannot locate libjvm"); 2176 char *rp = realpath(dli_fname, buf); 2177 if (rp == NULL) 2178 return; 2179 2180 if (strcmp(Arguments::sun_java_launcher(), "gamma") == 0) { 2181 // Support for the gamma launcher. Typical value for buf is 2182 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at 2183 // the right place in the string, then assume we are installed in a JDK and 2184 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix 2185 // up the path so it looks like libjvm.so is installed there (append a 2186 // fake suffix hotspot/libjvm.so). 2187 const char *p = buf + strlen(buf) - 1; 2188 for (int count = 0; p > buf && count < 5; ++count) { 2189 for (--p; p > buf && *p != '/'; --p) 2190 /* empty */ ; 2191 } 2192 2193 if (strncmp(p, "/jre/lib/", 9) != 0) { 2194 // Look for JAVA_HOME in the environment. 2195 char* java_home_var = ::getenv("JAVA_HOME"); 2196 if (java_home_var != NULL && java_home_var[0] != 0) { 2197 char* jrelib_p; 2198 int len; 2199 2200 // Check the current module name "libjvm.so" or "libjvm_g.so". 2201 p = strrchr(buf, '/'); 2202 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2203 p = strstr(p, "_g") ? "_g" : ""; 2204 2205 rp = realpath(java_home_var, buf); 2206 if (rp == NULL) 2207 return; 2208 2209 // determine if this is a legacy image or modules image 2210 // modules image doesn't have "jre" subdirectory 2211 len = strlen(buf); 2212 jrelib_p = buf + len; 2213 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2214 if (0 != access(buf, F_OK)) { 2215 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2216 } 2217 2218 if (0 == access(buf, F_OK)) { 2219 // Use current module name "libjvm[_g].so" instead of 2220 // "libjvm"debug_only("_g")".so" since for fastdebug version 2221 // we should have "libjvm.so" but debug_only("_g") adds "_g"! 2222 // It is used when we are choosing the HPI library's name 2223 // "libhpi[_g].so" in hpi::initialize_get_interface(). 2224 len = strlen(buf); 2225 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p); 2226 } else { 2227 // Go back to path of .so 2228 rp = realpath(dli_fname, buf); 2229 if (rp == NULL) 2230 return; 2231 } 2232 } 2233 } 2234 } 2235 2236 strcpy(saved_jvm_path, buf); 2237 } 2238 2239 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2240 // no prefix required, not even "_" 2241 } 2242 2243 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2244 // no suffix required 2245 } 2246 2247 //////////////////////////////////////////////////////////////////////////////// 2248 // sun.misc.Signal support 2249 2250 static volatile jint sigint_count = 0; 2251 2252 static void 2253 UserHandler(int sig, void *siginfo, void *context) { 2254 // 4511530 - sem_post is serialized and handled by the manager thread. When 2255 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2256 // don't want to flood the manager thread with sem_post requests. 2257 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) 2258 return; 2259 2260 // Ctrl-C is pressed during error reporting, likely because the error 2261 // handler fails to abort. Let VM die immediately. 2262 if (sig == SIGINT && is_error_reported()) { 2263 os::die(); 2264 } 2265 2266 os::signal_notify(sig); 2267 } 2268 2269 void* os::user_handler() { 2270 return CAST_FROM_FN_PTR(void*, UserHandler); 2271 } 2272 2273 extern "C" { 2274 typedef void (*sa_handler_t)(int); 2275 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2276 } 2277 2278 void* os::signal(int signal_number, void* handler) { 2279 struct sigaction sigAct, oldSigAct; 2280 2281 sigfillset(&(sigAct.sa_mask)); 2282 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2283 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2284 2285 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2286 // -1 means registration failed 2287 return (void *)-1; 2288 } 2289 2290 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2291 } 2292 2293 void os::signal_raise(int signal_number) { 2294 ::raise(signal_number); 2295 } 2296 2297 /* 2298 * The following code is moved from os.cpp for making this 2299 * code platform specific, which it is by its very nature. 2300 */ 2301 2302 // Will be modified when max signal is changed to be dynamic 2303 int os::sigexitnum_pd() { 2304 return NSIG; 2305 } 2306 2307 // a counter for each possible signal value 2308 static volatile jint pending_signals[NSIG+1] = { 0 }; 2309 2310 // Linux(POSIX) specific hand shaking semaphore. 2311 static sem_t sig_sem; 2312 2313 void os::signal_init_pd() { 2314 // Initialize signal structures 2315 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2316 2317 // Initialize signal semaphore 2318 ::sem_init(&sig_sem, 0, 0); 2319 } 2320 2321 void os::signal_notify(int sig) { 2322 Atomic::inc(&pending_signals[sig]); 2323 ::sem_post(&sig_sem); 2324 } 2325 2326 static int check_pending_signals(bool wait) { 2327 Atomic::store(0, &sigint_count); 2328 for (;;) { 2329 for (int i = 0; i < NSIG + 1; i++) { 2330 jint n = pending_signals[i]; 2331 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2332 return i; 2333 } 2334 } 2335 if (!wait) { 2336 return -1; 2337 } 2338 JavaThread *thread = JavaThread::current(); 2339 ThreadBlockInVM tbivm(thread); 2340 2341 bool threadIsSuspended; 2342 do { 2343 thread->set_suspend_equivalent(); 2344 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2345 ::sem_wait(&sig_sem); 2346 2347 // were we externally suspended while we were waiting? 2348 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2349 if (threadIsSuspended) { 2350 // 2351 // The semaphore has been incremented, but while we were waiting 2352 // another thread suspended us. We don't want to continue running 2353 // while suspended because that would surprise the thread that 2354 // suspended us. 2355 // 2356 ::sem_post(&sig_sem); 2357 2358 thread->java_suspend_self(); 2359 } 2360 } while (threadIsSuspended); 2361 } 2362 } 2363 2364 int os::signal_lookup() { 2365 return check_pending_signals(false); 2366 } 2367 2368 int os::signal_wait() { 2369 return check_pending_signals(true); 2370 } 2371 2372 //////////////////////////////////////////////////////////////////////////////// 2373 // Virtual Memory 2374 2375 int os::vm_page_size() { 2376 // Seems redundant as all get out 2377 assert(os::Linux::page_size() != -1, "must call os::init"); 2378 return os::Linux::page_size(); 2379 } 2380 2381 // Solaris allocates memory by pages. 2382 int os::vm_allocation_granularity() { 2383 assert(os::Linux::page_size() != -1, "must call os::init"); 2384 return os::Linux::page_size(); 2385 } 2386 2387 // Rationale behind this function: 2388 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2389 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2390 // samples for JITted code. Here we create private executable mapping over the code cache 2391 // and then we can use standard (well, almost, as mapping can change) way to provide 2392 // info for the reporting script by storing timestamp and location of symbol 2393 void linux_wrap_code(char* base, size_t size) { 2394 static volatile jint cnt = 0; 2395 2396 if (!UseOprofile) { 2397 return; 2398 } 2399 2400 char buf[PATH_MAX+1]; 2401 int num = Atomic::add(1, &cnt); 2402 2403 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2404 os::get_temp_directory(), os::current_process_id(), num); 2405 unlink(buf); 2406 2407 int fd = open(buf, O_CREAT | O_RDWR, S_IRWXU); 2408 2409 if (fd != -1) { 2410 off_t rv = lseek(fd, size-2, SEEK_SET); 2411 if (rv != (off_t)-1) { 2412 if (write(fd, "", 1) == 1) { 2413 mmap(base, size, 2414 PROT_READ|PROT_WRITE|PROT_EXEC, 2415 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2416 } 2417 } 2418 close(fd); 2419 unlink(buf); 2420 } 2421 } 2422 2423 // NOTE: Linux kernel does not really reserve the pages for us. 2424 // All it does is to check if there are enough free pages 2425 // left at the time of mmap(). This could be a potential 2426 // problem. 2427 bool os::commit_memory(char* addr, size_t size, bool exec) { 2428 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2429 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2430 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2431 return res != (uintptr_t) MAP_FAILED; 2432 } 2433 2434 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint, 2435 bool exec) { 2436 return commit_memory(addr, size, exec); 2437 } 2438 2439 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { } 2440 2441 void os::free_memory(char *addr, size_t bytes) { 2442 ::mmap(addr, bytes, PROT_READ | PROT_WRITE, 2443 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2444 } 2445 2446 void os::numa_make_global(char *addr, size_t bytes) { 2447 Linux::numa_interleave_memory(addr, bytes); 2448 } 2449 2450 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2451 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2452 } 2453 2454 bool os::numa_topology_changed() { return false; } 2455 2456 size_t os::numa_get_groups_num() { 2457 int max_node = Linux::numa_max_node(); 2458 return max_node > 0 ? max_node + 1 : 1; 2459 } 2460 2461 int os::numa_get_group_id() { 2462 int cpu_id = Linux::sched_getcpu(); 2463 if (cpu_id != -1) { 2464 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2465 if (lgrp_id != -1) { 2466 return lgrp_id; 2467 } 2468 } 2469 return 0; 2470 } 2471 2472 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2473 for (size_t i = 0; i < size; i++) { 2474 ids[i] = i; 2475 } 2476 return size; 2477 } 2478 2479 bool os::get_page_info(char *start, page_info* info) { 2480 return false; 2481 } 2482 2483 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) { 2484 return end; 2485 } 2486 2487 extern "C" void numa_warn(int number, char *where, ...) { } 2488 extern "C" void numa_error(char *where) { } 2489 2490 2491 // If we are running with libnuma version > 2, then we should 2492 // be trying to use symbols with versions 1.1 2493 // If we are running with earlier version, which did not have symbol versions, 2494 // we should use the base version. 2495 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2496 void *f = dlvsym(handle, name, "libnuma_1.1"); 2497 if (f == NULL) { 2498 f = dlsym(handle, name); 2499 } 2500 return f; 2501 } 2502 2503 bool os::Linux::libnuma_init() { 2504 // sched_getcpu() should be in libc. 2505 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2506 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2507 2508 if (sched_getcpu() != -1) { // Does it work? 2509 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2510 if (handle != NULL) { 2511 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2512 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2513 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2514 libnuma_dlsym(handle, "numa_max_node"))); 2515 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2516 libnuma_dlsym(handle, "numa_available"))); 2517 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2518 libnuma_dlsym(handle, "numa_tonode_memory"))); 2519 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2520 libnuma_dlsym(handle, "numa_interleave_memory"))); 2521 2522 2523 if (numa_available() != -1) { 2524 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2525 // Create a cpu -> node mapping 2526 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true); 2527 rebuild_cpu_to_node_map(); 2528 return true; 2529 } 2530 } 2531 } 2532 return false; 2533 } 2534 2535 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2536 // The table is later used in get_node_by_cpu(). 2537 void os::Linux::rebuild_cpu_to_node_map() { 2538 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2539 // in libnuma (possible values are starting from 16, 2540 // and continuing up with every other power of 2, but less 2541 // than the maximum number of CPUs supported by kernel), and 2542 // is a subject to change (in libnuma version 2 the requirements 2543 // are more reasonable) we'll just hardcode the number they use 2544 // in the library. 2545 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2546 2547 size_t cpu_num = os::active_processor_count(); 2548 size_t cpu_map_size = NCPUS / BitsPerCLong; 2549 size_t cpu_map_valid_size = 2550 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2551 2552 cpu_to_node()->clear(); 2553 cpu_to_node()->at_grow(cpu_num - 1); 2554 size_t node_num = numa_get_groups_num(); 2555 2556 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size); 2557 for (size_t i = 0; i < node_num; i++) { 2558 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2559 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2560 if (cpu_map[j] != 0) { 2561 for (size_t k = 0; k < BitsPerCLong; k++) { 2562 if (cpu_map[j] & (1UL << k)) { 2563 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2564 } 2565 } 2566 } 2567 } 2568 } 2569 } 2570 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2571 } 2572 2573 int os::Linux::get_node_by_cpu(int cpu_id) { 2574 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2575 return cpu_to_node()->at(cpu_id); 2576 } 2577 return -1; 2578 } 2579 2580 GrowableArray<int>* os::Linux::_cpu_to_node; 2581 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2582 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2583 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2584 os::Linux::numa_available_func_t os::Linux::_numa_available; 2585 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2586 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2587 unsigned long* os::Linux::_numa_all_nodes; 2588 2589 bool os::uncommit_memory(char* addr, size_t size) { 2590 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2591 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2592 return res != (uintptr_t) MAP_FAILED; 2593 } 2594 2595 // Linux uses a growable mapping for the stack, and if the mapping for 2596 // the stack guard pages is not removed when we detach a thread the 2597 // stack cannot grow beyond the pages where the stack guard was 2598 // mapped. If at some point later in the process the stack expands to 2599 // that point, the Linux kernel cannot expand the stack any further 2600 // because the guard pages are in the way, and a segfault occurs. 2601 // 2602 // However, it's essential not to split the stack region by unmapping 2603 // a region (leaving a hole) that's already part of the stack mapping, 2604 // so if the stack mapping has already grown beyond the guard pages at 2605 // the time we create them, we have to truncate the stack mapping. 2606 // So, we need to know the extent of the stack mapping when 2607 // create_stack_guard_pages() is called. 2608 2609 // Find the bounds of the stack mapping. Return true for success. 2610 // 2611 // We only need this for stacks that are growable: at the time of 2612 // writing thread stacks don't use growable mappings (i.e. those 2613 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2614 // only applies to the main thread. 2615 static bool 2616 get_stack_bounds(uintptr_t *bottom, uintptr_t *top) 2617 { 2618 FILE *f = fopen("/proc/self/maps", "r"); 2619 if (f == NULL) 2620 return false; 2621 2622 while (!feof(f)) { 2623 size_t dummy; 2624 char *str = NULL; 2625 ssize_t len = getline(&str, &dummy, f); 2626 if (len == -1) { 2627 fclose(f); 2628 return false; 2629 } 2630 2631 if (len > 0 && str[len-1] == '\n') { 2632 str[len-1] = 0; 2633 len--; 2634 } 2635 2636 static const char *stack_str = "[stack]"; 2637 if (len > (ssize_t)strlen(stack_str) 2638 && (strcmp(str + len - strlen(stack_str), stack_str) == 0)) { 2639 if (sscanf(str, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) { 2640 uintptr_t sp = (uintptr_t)__builtin_frame_address(0); 2641 if (sp >= *bottom && sp <= *top) { 2642 free(str); 2643 fclose(f); 2644 return true; 2645 } 2646 } 2647 } 2648 free(str); 2649 } 2650 fclose(f); 2651 return false; 2652 } 2653 2654 // If the (growable) stack mapping already extends beyond the point 2655 // where we're going to put our guard pages, truncate the mapping at 2656 // that point by munmap()ping it. This ensures that when we later 2657 // munmap() the guard pages we don't leave a hole in the stack 2658 // mapping. This only affects the main/initial thread, but guard 2659 // against future OS changes 2660 bool os::create_stack_guard_pages(char* addr, size_t size) { 2661 uintptr_t stack_extent, stack_base; 2662 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2663 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2664 assert(os::Linux::is_initial_thread(), 2665 "growable stack in non-initial thread"); 2666 if (stack_extent < (uintptr_t)addr) 2667 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent); 2668 } 2669 2670 return os::commit_memory(addr, size); 2671 } 2672 2673 // If this is a growable mapping, remove the guard pages entirely by 2674 // munmap()ping them. If not, just call uncommit_memory(). This only 2675 // affects the main/initial thread, but guard against future OS changes 2676 bool os::remove_stack_guard_pages(char* addr, size_t size) { 2677 uintptr_t stack_extent, stack_base; 2678 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2679 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2680 assert(os::Linux::is_initial_thread(), 2681 "growable stack in non-initial thread"); 2682 2683 return ::munmap(addr, size) == 0; 2684 } 2685 2686 return os::uncommit_memory(addr, size); 2687 } 2688 2689 static address _highest_vm_reserved_address = NULL; 2690 2691 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 2692 // at 'requested_addr'. If there are existing memory mappings at the same 2693 // location, however, they will be overwritten. If 'fixed' is false, 2694 // 'requested_addr' is only treated as a hint, the return value may or 2695 // may not start from the requested address. Unlike Linux mmap(), this 2696 // function returns NULL to indicate failure. 2697 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 2698 char * addr; 2699 int flags; 2700 2701 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 2702 if (fixed) { 2703 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 2704 flags |= MAP_FIXED; 2705 } 2706 2707 // Map uncommitted pages PROT_READ and PROT_WRITE, change access 2708 // to PROT_EXEC if executable when we commit the page. 2709 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE, 2710 flags, -1, 0); 2711 2712 if (addr != MAP_FAILED) { 2713 // anon_mmap() should only get called during VM initialization, 2714 // don't need lock (actually we can skip locking even it can be called 2715 // from multiple threads, because _highest_vm_reserved_address is just a 2716 // hint about the upper limit of non-stack memory regions.) 2717 if ((address)addr + bytes > _highest_vm_reserved_address) { 2718 _highest_vm_reserved_address = (address)addr + bytes; 2719 } 2720 } 2721 2722 return addr == MAP_FAILED ? NULL : addr; 2723 } 2724 2725 // Don't update _highest_vm_reserved_address, because there might be memory 2726 // regions above addr + size. If so, releasing a memory region only creates 2727 // a hole in the address space, it doesn't help prevent heap-stack collision. 2728 // 2729 static int anon_munmap(char * addr, size_t size) { 2730 return ::munmap(addr, size) == 0; 2731 } 2732 2733 char* os::reserve_memory(size_t bytes, char* requested_addr, 2734 size_t alignment_hint) { 2735 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 2736 } 2737 2738 bool os::release_memory(char* addr, size_t size) { 2739 return anon_munmap(addr, size); 2740 } 2741 2742 static address highest_vm_reserved_address() { 2743 return _highest_vm_reserved_address; 2744 } 2745 2746 static bool linux_mprotect(char* addr, size_t size, int prot) { 2747 // Linux wants the mprotect address argument to be page aligned. 2748 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 2749 2750 // According to SUSv3, mprotect() should only be used with mappings 2751 // established by mmap(), and mmap() always maps whole pages. Unaligned 2752 // 'addr' likely indicates problem in the VM (e.g. trying to change 2753 // protection of malloc'ed or statically allocated memory). Check the 2754 // caller if you hit this assert. 2755 assert(addr == bottom, "sanity check"); 2756 2757 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 2758 return ::mprotect(bottom, size, prot) == 0; 2759 } 2760 2761 // Set protections specified 2762 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 2763 bool is_committed) { 2764 unsigned int p = 0; 2765 switch (prot) { 2766 case MEM_PROT_NONE: p = PROT_NONE; break; 2767 case MEM_PROT_READ: p = PROT_READ; break; 2768 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 2769 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 2770 default: 2771 ShouldNotReachHere(); 2772 } 2773 // is_committed is unused. 2774 return linux_mprotect(addr, bytes, p); 2775 } 2776 2777 bool os::guard_memory(char* addr, size_t size) { 2778 return linux_mprotect(addr, size, PROT_NONE); 2779 } 2780 2781 bool os::unguard_memory(char* addr, size_t size) { 2782 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 2783 } 2784 2785 // Large page support 2786 2787 static size_t _large_page_size = 0; 2788 2789 bool os::large_page_init() { 2790 if (!UseLargePages) return false; 2791 2792 if (LargePageSizeInBytes) { 2793 _large_page_size = LargePageSizeInBytes; 2794 } else { 2795 // large_page_size on Linux is used to round up heap size. x86 uses either 2796 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 2797 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 2798 // page as large as 256M. 2799 // 2800 // Here we try to figure out page size by parsing /proc/meminfo and looking 2801 // for a line with the following format: 2802 // Hugepagesize: 2048 kB 2803 // 2804 // If we can't determine the value (e.g. /proc is not mounted, or the text 2805 // format has been changed), we'll use the largest page size supported by 2806 // the processor. 2807 2808 #ifndef ZERO 2809 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 2810 ARM_ONLY(2 * M) PPC_ONLY(4 * M); 2811 #endif // ZERO 2812 2813 FILE *fp = fopen("/proc/meminfo", "r"); 2814 if (fp) { 2815 while (!feof(fp)) { 2816 int x = 0; 2817 char buf[16]; 2818 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 2819 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 2820 _large_page_size = x * K; 2821 break; 2822 } 2823 } else { 2824 // skip to next line 2825 for (;;) { 2826 int ch = fgetc(fp); 2827 if (ch == EOF || ch == (int)'\n') break; 2828 } 2829 } 2830 } 2831 fclose(fp); 2832 } 2833 } 2834 2835 const size_t default_page_size = (size_t)Linux::page_size(); 2836 if (_large_page_size > default_page_size) { 2837 _page_sizes[0] = _large_page_size; 2838 _page_sizes[1] = default_page_size; 2839 _page_sizes[2] = 0; 2840 } 2841 2842 // Large page support is available on 2.6 or newer kernel, some vendors 2843 // (e.g. Redhat) have backported it to their 2.4 based distributions. 2844 // We optimistically assume the support is available. If later it turns out 2845 // not true, VM will automatically switch to use regular page size. 2846 return true; 2847 } 2848 2849 #ifndef SHM_HUGETLB 2850 #define SHM_HUGETLB 04000 2851 #endif 2852 2853 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) { 2854 // "exec" is passed in but not used. Creating the shared image for 2855 // the code cache doesn't have an SHM_X executable permission to check. 2856 assert(UseLargePages, "only for large pages"); 2857 2858 key_t key = IPC_PRIVATE; 2859 char *addr; 2860 2861 bool warn_on_failure = UseLargePages && 2862 (!FLAG_IS_DEFAULT(UseLargePages) || 2863 !FLAG_IS_DEFAULT(LargePageSizeInBytes) 2864 ); 2865 char msg[128]; 2866 2867 // Create a large shared memory region to attach to based on size. 2868 // Currently, size is the total size of the heap 2869 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 2870 if (shmid == -1) { 2871 // Possible reasons for shmget failure: 2872 // 1. shmmax is too small for Java heap. 2873 // > check shmmax value: cat /proc/sys/kernel/shmmax 2874 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 2875 // 2. not enough large page memory. 2876 // > check available large pages: cat /proc/meminfo 2877 // > increase amount of large pages: 2878 // echo new_value > /proc/sys/vm/nr_hugepages 2879 // Note 1: different Linux may use different name for this property, 2880 // e.g. on Redhat AS-3 it is "hugetlb_pool". 2881 // Note 2: it's possible there's enough physical memory available but 2882 // they are so fragmented after a long run that they can't 2883 // coalesce into large pages. Try to reserve large pages when 2884 // the system is still "fresh". 2885 if (warn_on_failure) { 2886 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 2887 warning(msg); 2888 } 2889 return NULL; 2890 } 2891 2892 // attach to the region 2893 addr = (char*)shmat(shmid, req_addr, 0); 2894 int err = errno; 2895 2896 // Remove shmid. If shmat() is successful, the actual shared memory segment 2897 // will be deleted when it's detached by shmdt() or when the process 2898 // terminates. If shmat() is not successful this will remove the shared 2899 // segment immediately. 2900 shmctl(shmid, IPC_RMID, NULL); 2901 2902 if ((intptr_t)addr == -1) { 2903 if (warn_on_failure) { 2904 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 2905 warning(msg); 2906 } 2907 return NULL; 2908 } 2909 2910 return addr; 2911 } 2912 2913 bool os::release_memory_special(char* base, size_t bytes) { 2914 // detaching the SHM segment will also delete it, see reserve_memory_special() 2915 int rslt = shmdt(base); 2916 return rslt == 0; 2917 } 2918 2919 size_t os::large_page_size() { 2920 return _large_page_size; 2921 } 2922 2923 // Linux does not support anonymous mmap with large page memory. The only way 2924 // to reserve large page memory without file backing is through SysV shared 2925 // memory API. The entire memory region is committed and pinned upfront. 2926 // Hopefully this will change in the future... 2927 bool os::can_commit_large_page_memory() { 2928 return false; 2929 } 2930 2931 bool os::can_execute_large_page_memory() { 2932 return false; 2933 } 2934 2935 // Reserve memory at an arbitrary address, only if that area is 2936 // available (and not reserved for something else). 2937 2938 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 2939 const int max_tries = 10; 2940 char* base[max_tries]; 2941 size_t size[max_tries]; 2942 const size_t gap = 0x000000; 2943 2944 // Assert only that the size is a multiple of the page size, since 2945 // that's all that mmap requires, and since that's all we really know 2946 // about at this low abstraction level. If we need higher alignment, 2947 // we can either pass an alignment to this method or verify alignment 2948 // in one of the methods further up the call chain. See bug 5044738. 2949 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 2950 2951 // Repeatedly allocate blocks until the block is allocated at the 2952 // right spot. Give up after max_tries. Note that reserve_memory() will 2953 // automatically update _highest_vm_reserved_address if the call is 2954 // successful. The variable tracks the highest memory address every reserved 2955 // by JVM. It is used to detect heap-stack collision if running with 2956 // fixed-stack LinuxThreads. Because here we may attempt to reserve more 2957 // space than needed, it could confuse the collision detecting code. To 2958 // solve the problem, save current _highest_vm_reserved_address and 2959 // calculate the correct value before return. 2960 address old_highest = _highest_vm_reserved_address; 2961 2962 // Linux mmap allows caller to pass an address as hint; give it a try first, 2963 // if kernel honors the hint then we can return immediately. 2964 char * addr = anon_mmap(requested_addr, bytes, false); 2965 if (addr == requested_addr) { 2966 return requested_addr; 2967 } 2968 2969 if (addr != NULL) { 2970 // mmap() is successful but it fails to reserve at the requested address 2971 anon_munmap(addr, bytes); 2972 } 2973 2974 int i; 2975 for (i = 0; i < max_tries; ++i) { 2976 base[i] = reserve_memory(bytes); 2977 2978 if (base[i] != NULL) { 2979 // Is this the block we wanted? 2980 if (base[i] == requested_addr) { 2981 size[i] = bytes; 2982 break; 2983 } 2984 2985 // Does this overlap the block we wanted? Give back the overlapped 2986 // parts and try again. 2987 2988 size_t top_overlap = requested_addr + (bytes + gap) - base[i]; 2989 if (top_overlap >= 0 && top_overlap < bytes) { 2990 unmap_memory(base[i], top_overlap); 2991 base[i] += top_overlap; 2992 size[i] = bytes - top_overlap; 2993 } else { 2994 size_t bottom_overlap = base[i] + bytes - requested_addr; 2995 if (bottom_overlap >= 0 && bottom_overlap < bytes) { 2996 unmap_memory(requested_addr, bottom_overlap); 2997 size[i] = bytes - bottom_overlap; 2998 } else { 2999 size[i] = bytes; 3000 } 3001 } 3002 } 3003 } 3004 3005 // Give back the unused reserved pieces. 3006 3007 for (int j = 0; j < i; ++j) { 3008 if (base[j] != NULL) { 3009 unmap_memory(base[j], size[j]); 3010 } 3011 } 3012 3013 if (i < max_tries) { 3014 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes); 3015 return requested_addr; 3016 } else { 3017 _highest_vm_reserved_address = old_highest; 3018 return NULL; 3019 } 3020 } 3021 3022 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3023 return ::read(fd, buf, nBytes); 3024 } 3025 3026 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation. 3027 // Solaris uses poll(), linux uses park(). 3028 // Poll() is likely a better choice, assuming that Thread.interrupt() 3029 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with 3030 // SIGSEGV, see 4355769. 3031 3032 const int NANOSECS_PER_MILLISECS = 1000000; 3033 3034 int os::sleep(Thread* thread, jlong millis, bool interruptible) { 3035 assert(thread == Thread::current(), "thread consistency check"); 3036 3037 ParkEvent * const slp = thread->_SleepEvent ; 3038 slp->reset() ; 3039 OrderAccess::fence() ; 3040 3041 if (interruptible) { 3042 jlong prevtime = javaTimeNanos(); 3043 3044 for (;;) { 3045 if (os::is_interrupted(thread, true)) { 3046 return OS_INTRPT; 3047 } 3048 3049 jlong newtime = javaTimeNanos(); 3050 3051 if (newtime - prevtime < 0) { 3052 // time moving backwards, should only happen if no monotonic clock 3053 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3054 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3055 } else { 3056 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS; 3057 } 3058 3059 if(millis <= 0) { 3060 return OS_OK; 3061 } 3062 3063 prevtime = newtime; 3064 3065 { 3066 assert(thread->is_Java_thread(), "sanity check"); 3067 JavaThread *jt = (JavaThread *) thread; 3068 ThreadBlockInVM tbivm(jt); 3069 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 3070 3071 jt->set_suspend_equivalent(); 3072 // cleared by handle_special_suspend_equivalent_condition() or 3073 // java_suspend_self() via check_and_wait_while_suspended() 3074 3075 slp->park(millis); 3076 3077 // were we externally suspended while we were waiting? 3078 jt->check_and_wait_while_suspended(); 3079 } 3080 } 3081 } else { 3082 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 3083 jlong prevtime = javaTimeNanos(); 3084 3085 for (;;) { 3086 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 3087 // the 1st iteration ... 3088 jlong newtime = javaTimeNanos(); 3089 3090 if (newtime - prevtime < 0) { 3091 // time moving backwards, should only happen if no monotonic clock 3092 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3093 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3094 } else { 3095 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS; 3096 } 3097 3098 if(millis <= 0) break ; 3099 3100 prevtime = newtime; 3101 slp->park(millis); 3102 } 3103 return OS_OK ; 3104 } 3105 } 3106 3107 int os::naked_sleep() { 3108 // %% make the sleep time an integer flag. for now use 1 millisec. 3109 return os::sleep(Thread::current(), 1, false); 3110 } 3111 3112 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3113 void os::infinite_sleep() { 3114 while (true) { // sleep forever ... 3115 ::sleep(100); // ... 100 seconds at a time 3116 } 3117 } 3118 3119 // Used to convert frequent JVM_Yield() to nops 3120 bool os::dont_yield() { 3121 return DontYieldALot; 3122 } 3123 3124 void os::yield() { 3125 sched_yield(); 3126 } 3127 3128 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;} 3129 3130 void os::yield_all(int attempts) { 3131 // Yields to all threads, including threads with lower priorities 3132 // Threads on Linux are all with same priority. The Solaris style 3133 // os::yield_all() with nanosleep(1ms) is not necessary. 3134 sched_yield(); 3135 } 3136 3137 // Called from the tight loops to possibly influence time-sharing heuristics 3138 void os::loop_breaker(int attempts) { 3139 os::yield_all(attempts); 3140 } 3141 3142 //////////////////////////////////////////////////////////////////////////////// 3143 // thread priority support 3144 3145 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3146 // only supports dynamic priority, static priority must be zero. For real-time 3147 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3148 // However, for large multi-threaded applications, SCHED_RR is not only slower 3149 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3150 // of 5 runs - Sep 2005). 3151 // 3152 // The following code actually changes the niceness of kernel-thread/LWP. It 3153 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3154 // not the entire user process, and user level threads are 1:1 mapped to kernel 3155 // threads. It has always been the case, but could change in the future. For 3156 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3157 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3158 3159 int os::java_to_os_priority[MaxPriority + 1] = { 3160 19, // 0 Entry should never be used 3161 3162 4, // 1 MinPriority 3163 3, // 2 3164 2, // 3 3165 3166 1, // 4 3167 0, // 5 NormPriority 3168 -1, // 6 3169 3170 -2, // 7 3171 -3, // 8 3172 -4, // 9 NearMaxPriority 3173 3174 -5 // 10 MaxPriority 3175 }; 3176 3177 static int prio_init() { 3178 if (ThreadPriorityPolicy == 1) { 3179 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3180 // if effective uid is not root. Perhaps, a more elegant way of doing 3181 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3182 if (geteuid() != 0) { 3183 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3184 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3185 } 3186 ThreadPriorityPolicy = 0; 3187 } 3188 } 3189 return 0; 3190 } 3191 3192 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3193 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK; 3194 3195 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3196 return (ret == 0) ? OS_OK : OS_ERR; 3197 } 3198 3199 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) { 3200 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) { 3201 *priority_ptr = java_to_os_priority[NormPriority]; 3202 return OS_OK; 3203 } 3204 3205 errno = 0; 3206 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3207 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3208 } 3209 3210 // Hint to the underlying OS that a task switch would not be good. 3211 // Void return because it's a hint and can fail. 3212 void os::hint_no_preempt() {} 3213 3214 //////////////////////////////////////////////////////////////////////////////// 3215 // suspend/resume support 3216 3217 // the low-level signal-based suspend/resume support is a remnant from the 3218 // old VM-suspension that used to be for java-suspension, safepoints etc, 3219 // within hotspot. Now there is a single use-case for this: 3220 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3221 // that runs in the watcher thread. 3222 // The remaining code is greatly simplified from the more general suspension 3223 // code that used to be used. 3224 // 3225 // The protocol is quite simple: 3226 // - suspend: 3227 // - sends a signal to the target thread 3228 // - polls the suspend state of the osthread using a yield loop 3229 // - target thread signal handler (SR_handler) sets suspend state 3230 // and blocks in sigsuspend until continued 3231 // - resume: 3232 // - sets target osthread state to continue 3233 // - sends signal to end the sigsuspend loop in the SR_handler 3234 // 3235 // Note that the SR_lock plays no role in this suspend/resume protocol. 3236 // 3237 3238 static void resume_clear_context(OSThread *osthread) { 3239 osthread->set_ucontext(NULL); 3240 osthread->set_siginfo(NULL); 3241 3242 // notify the suspend action is completed, we have now resumed 3243 osthread->sr.clear_suspended(); 3244 } 3245 3246 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) { 3247 osthread->set_ucontext(context); 3248 osthread->set_siginfo(siginfo); 3249 } 3250 3251 // 3252 // Handler function invoked when a thread's execution is suspended or 3253 // resumed. We have to be careful that only async-safe functions are 3254 // called here (Note: most pthread functions are not async safe and 3255 // should be avoided.) 3256 // 3257 // Note: sigwait() is a more natural fit than sigsuspend() from an 3258 // interface point of view, but sigwait() prevents the signal hander 3259 // from being run. libpthread would get very confused by not having 3260 // its signal handlers run and prevents sigwait()'s use with the 3261 // mutex granting granting signal. 3262 // 3263 // Currently only ever called on the VMThread 3264 // 3265 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3266 // Save and restore errno to avoid confusing native code with EINTR 3267 // after sigsuspend. 3268 int old_errno = errno; 3269 3270 Thread* thread = Thread::current(); 3271 OSThread* osthread = thread->osthread(); 3272 assert(thread->is_VM_thread(), "Must be VMThread"); 3273 // read current suspend action 3274 int action = osthread->sr.suspend_action(); 3275 if (action == SR_SUSPEND) { 3276 suspend_save_context(osthread, siginfo, context); 3277 3278 // Notify the suspend action is about to be completed. do_suspend() 3279 // waits until SR_SUSPENDED is set and then returns. We will wait 3280 // here for a resume signal and that completes the suspend-other 3281 // action. do_suspend/do_resume is always called as a pair from 3282 // the same thread - so there are no races 3283 3284 // notify the caller 3285 osthread->sr.set_suspended(); 3286 3287 sigset_t suspend_set; // signals for sigsuspend() 3288 3289 // get current set of blocked signals and unblock resume signal 3290 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3291 sigdelset(&suspend_set, SR_signum); 3292 3293 // wait here until we are resumed 3294 do { 3295 sigsuspend(&suspend_set); 3296 // ignore all returns until we get a resume signal 3297 } while (osthread->sr.suspend_action() != SR_CONTINUE); 3298 3299 resume_clear_context(osthread); 3300 3301 } else { 3302 assert(action == SR_CONTINUE, "unexpected sr action"); 3303 // nothing special to do - just leave the handler 3304 } 3305 3306 errno = old_errno; 3307 } 3308 3309 3310 static int SR_initialize() { 3311 struct sigaction act; 3312 char *s; 3313 /* Get signal number to use for suspend/resume */ 3314 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3315 int sig = ::strtol(s, 0, 10); 3316 if (sig > 0 || sig < _NSIG) { 3317 SR_signum = sig; 3318 } 3319 } 3320 3321 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 3322 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 3323 3324 sigemptyset(&SR_sigset); 3325 sigaddset(&SR_sigset, SR_signum); 3326 3327 /* Set up signal handler for suspend/resume */ 3328 act.sa_flags = SA_RESTART|SA_SIGINFO; 3329 act.sa_handler = (void (*)(int)) SR_handler; 3330 3331 // SR_signum is blocked by default. 3332 // 4528190 - We also need to block pthread restart signal (32 on all 3333 // supported Linux platforms). Note that LinuxThreads need to block 3334 // this signal for all threads to work properly. So we don't have 3335 // to use hard-coded signal number when setting up the mask. 3336 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 3337 3338 if (sigaction(SR_signum, &act, 0) == -1) { 3339 return -1; 3340 } 3341 3342 // Save signal flag 3343 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 3344 return 0; 3345 } 3346 3347 static int SR_finalize() { 3348 return 0; 3349 } 3350 3351 3352 // returns true on success and false on error - really an error is fatal 3353 // but this seems the normal response to library errors 3354 static bool do_suspend(OSThread* osthread) { 3355 // mark as suspended and send signal 3356 osthread->sr.set_suspend_action(SR_SUSPEND); 3357 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3358 assert_status(status == 0, status, "pthread_kill"); 3359 3360 // check status and wait until notified of suspension 3361 if (status == 0) { 3362 for (int i = 0; !osthread->sr.is_suspended(); i++) { 3363 os::yield_all(i); 3364 } 3365 osthread->sr.set_suspend_action(SR_NONE); 3366 return true; 3367 } 3368 else { 3369 osthread->sr.set_suspend_action(SR_NONE); 3370 return false; 3371 } 3372 } 3373 3374 static void do_resume(OSThread* osthread) { 3375 assert(osthread->sr.is_suspended(), "thread should be suspended"); 3376 osthread->sr.set_suspend_action(SR_CONTINUE); 3377 3378 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3379 assert_status(status == 0, status, "pthread_kill"); 3380 // check status and wait unit notified of resumption 3381 if (status == 0) { 3382 for (int i = 0; osthread->sr.is_suspended(); i++) { 3383 os::yield_all(i); 3384 } 3385 } 3386 osthread->sr.set_suspend_action(SR_NONE); 3387 } 3388 3389 //////////////////////////////////////////////////////////////////////////////// 3390 // interrupt support 3391 3392 void os::interrupt(Thread* thread) { 3393 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3394 "possibility of dangling Thread pointer"); 3395 3396 OSThread* osthread = thread->osthread(); 3397 3398 if (!osthread->interrupted()) { 3399 osthread->set_interrupted(true); 3400 // More than one thread can get here with the same value of osthread, 3401 // resulting in multiple notifications. We do, however, want the store 3402 // to interrupted() to be visible to other threads before we execute unpark(). 3403 OrderAccess::fence(); 3404 ParkEvent * const slp = thread->_SleepEvent ; 3405 if (slp != NULL) slp->unpark() ; 3406 } 3407 3408 // For JSR166. Unpark even if interrupt status already was set 3409 if (thread->is_Java_thread()) 3410 ((JavaThread*)thread)->parker()->unpark(); 3411 3412 ParkEvent * ev = thread->_ParkEvent ; 3413 if (ev != NULL) ev->unpark() ; 3414 3415 } 3416 3417 bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 3418 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3419 "possibility of dangling Thread pointer"); 3420 3421 OSThread* osthread = thread->osthread(); 3422 3423 bool interrupted = osthread->interrupted(); 3424 3425 if (interrupted && clear_interrupted) { 3426 osthread->set_interrupted(false); 3427 // consider thread->_SleepEvent->reset() ... optional optimization 3428 } 3429 3430 return interrupted; 3431 } 3432 3433 /////////////////////////////////////////////////////////////////////////////////// 3434 // signal handling (except suspend/resume) 3435 3436 // This routine may be used by user applications as a "hook" to catch signals. 3437 // The user-defined signal handler must pass unrecognized signals to this 3438 // routine, and if it returns true (non-zero), then the signal handler must 3439 // return immediately. If the flag "abort_if_unrecognized" is true, then this 3440 // routine will never retun false (zero), but instead will execute a VM panic 3441 // routine kill the process. 3442 // 3443 // If this routine returns false, it is OK to call it again. This allows 3444 // the user-defined signal handler to perform checks either before or after 3445 // the VM performs its own checks. Naturally, the user code would be making 3446 // a serious error if it tried to handle an exception (such as a null check 3447 // or breakpoint) that the VM was generating for its own correct operation. 3448 // 3449 // This routine may recognize any of the following kinds of signals: 3450 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 3451 // It should be consulted by handlers for any of those signals. 3452 // 3453 // The caller of this routine must pass in the three arguments supplied 3454 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 3455 // field of the structure passed to sigaction(). This routine assumes that 3456 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 3457 // 3458 // Note that the VM will print warnings if it detects conflicting signal 3459 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 3460 // 3461 extern "C" int 3462 JVM_handle_linux_signal(int signo, siginfo_t* siginfo, 3463 void* ucontext, int abort_if_unrecognized); 3464 3465 void signalHandler(int sig, siginfo_t* info, void* uc) { 3466 assert(info != NULL && uc != NULL, "it must be old kernel"); 3467 JVM_handle_linux_signal(sig, info, uc, true); 3468 } 3469 3470 3471 // This boolean allows users to forward their own non-matching signals 3472 // to JVM_handle_linux_signal, harmlessly. 3473 bool os::Linux::signal_handlers_are_installed = false; 3474 3475 // For signal-chaining 3476 struct sigaction os::Linux::sigact[MAXSIGNUM]; 3477 unsigned int os::Linux::sigs = 0; 3478 bool os::Linux::libjsig_is_loaded = false; 3479 typedef struct sigaction *(*get_signal_t)(int); 3480 get_signal_t os::Linux::get_signal_action = NULL; 3481 3482 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 3483 struct sigaction *actp = NULL; 3484 3485 if (libjsig_is_loaded) { 3486 // Retrieve the old signal handler from libjsig 3487 actp = (*get_signal_action)(sig); 3488 } 3489 if (actp == NULL) { 3490 // Retrieve the preinstalled signal handler from jvm 3491 actp = get_preinstalled_handler(sig); 3492 } 3493 3494 return actp; 3495 } 3496 3497 static bool call_chained_handler(struct sigaction *actp, int sig, 3498 siginfo_t *siginfo, void *context) { 3499 // Call the old signal handler 3500 if (actp->sa_handler == SIG_DFL) { 3501 // It's more reasonable to let jvm treat it as an unexpected exception 3502 // instead of taking the default action. 3503 return false; 3504 } else if (actp->sa_handler != SIG_IGN) { 3505 if ((actp->sa_flags & SA_NODEFER) == 0) { 3506 // automaticlly block the signal 3507 sigaddset(&(actp->sa_mask), sig); 3508 } 3509 3510 sa_handler_t hand; 3511 sa_sigaction_t sa; 3512 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 3513 // retrieve the chained handler 3514 if (siginfo_flag_set) { 3515 sa = actp->sa_sigaction; 3516 } else { 3517 hand = actp->sa_handler; 3518 } 3519 3520 if ((actp->sa_flags & SA_RESETHAND) != 0) { 3521 actp->sa_handler = SIG_DFL; 3522 } 3523 3524 // try to honor the signal mask 3525 sigset_t oset; 3526 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 3527 3528 // call into the chained handler 3529 if (siginfo_flag_set) { 3530 (*sa)(sig, siginfo, context); 3531 } else { 3532 (*hand)(sig); 3533 } 3534 3535 // restore the signal mask 3536 pthread_sigmask(SIG_SETMASK, &oset, 0); 3537 } 3538 // Tell jvm's signal handler the signal is taken care of. 3539 return true; 3540 } 3541 3542 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 3543 bool chained = false; 3544 // signal-chaining 3545 if (UseSignalChaining) { 3546 struct sigaction *actp = get_chained_signal_action(sig); 3547 if (actp != NULL) { 3548 chained = call_chained_handler(actp, sig, siginfo, context); 3549 } 3550 } 3551 return chained; 3552 } 3553 3554 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 3555 if ((( (unsigned int)1 << sig ) & sigs) != 0) { 3556 return &sigact[sig]; 3557 } 3558 return NULL; 3559 } 3560 3561 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 3562 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3563 sigact[sig] = oldAct; 3564 sigs |= (unsigned int)1 << sig; 3565 } 3566 3567 // for diagnostic 3568 int os::Linux::sigflags[MAXSIGNUM]; 3569 3570 int os::Linux::get_our_sigflags(int sig) { 3571 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3572 return sigflags[sig]; 3573 } 3574 3575 void os::Linux::set_our_sigflags(int sig, int flags) { 3576 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3577 sigflags[sig] = flags; 3578 } 3579 3580 void os::Linux::set_signal_handler(int sig, bool set_installed) { 3581 // Check for overwrite. 3582 struct sigaction oldAct; 3583 sigaction(sig, (struct sigaction*)NULL, &oldAct); 3584 3585 void* oldhand = oldAct.sa_sigaction 3586 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3587 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3588 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 3589 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 3590 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 3591 if (AllowUserSignalHandlers || !set_installed) { 3592 // Do not overwrite; user takes responsibility to forward to us. 3593 return; 3594 } else if (UseSignalChaining) { 3595 // save the old handler in jvm 3596 save_preinstalled_handler(sig, oldAct); 3597 // libjsig also interposes the sigaction() call below and saves the 3598 // old sigaction on it own. 3599 } else { 3600 fatal(err_msg("Encountered unexpected pre-existing sigaction handler " 3601 "%#lx for signal %d.", (long)oldhand, sig)); 3602 } 3603 } 3604 3605 struct sigaction sigAct; 3606 sigfillset(&(sigAct.sa_mask)); 3607 sigAct.sa_handler = SIG_DFL; 3608 if (!set_installed) { 3609 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3610 } else { 3611 sigAct.sa_sigaction = signalHandler; 3612 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3613 } 3614 // Save flags, which are set by ours 3615 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3616 sigflags[sig] = sigAct.sa_flags; 3617 3618 int ret = sigaction(sig, &sigAct, &oldAct); 3619 assert(ret == 0, "check"); 3620 3621 void* oldhand2 = oldAct.sa_sigaction 3622 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3623 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3624 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 3625 } 3626 3627 // install signal handlers for signals that HotSpot needs to 3628 // handle in order to support Java-level exception handling. 3629 3630 void os::Linux::install_signal_handlers() { 3631 if (!signal_handlers_are_installed) { 3632 signal_handlers_are_installed = true; 3633 3634 // signal-chaining 3635 typedef void (*signal_setting_t)(); 3636 signal_setting_t begin_signal_setting = NULL; 3637 signal_setting_t end_signal_setting = NULL; 3638 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3639 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 3640 if (begin_signal_setting != NULL) { 3641 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3642 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 3643 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 3644 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 3645 libjsig_is_loaded = true; 3646 assert(UseSignalChaining, "should enable signal-chaining"); 3647 } 3648 if (libjsig_is_loaded) { 3649 // Tell libjsig jvm is setting signal handlers 3650 (*begin_signal_setting)(); 3651 } 3652 3653 set_signal_handler(SIGSEGV, true); 3654 set_signal_handler(SIGPIPE, true); 3655 set_signal_handler(SIGBUS, true); 3656 set_signal_handler(SIGILL, true); 3657 set_signal_handler(SIGFPE, true); 3658 set_signal_handler(SIGXFSZ, true); 3659 3660 if (libjsig_is_loaded) { 3661 // Tell libjsig jvm finishes setting signal handlers 3662 (*end_signal_setting)(); 3663 } 3664 3665 // We don't activate signal checker if libjsig is in place, we trust ourselves 3666 // and if UserSignalHandler is installed all bets are off 3667 if (CheckJNICalls) { 3668 if (libjsig_is_loaded) { 3669 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 3670 check_signals = false; 3671 } 3672 if (AllowUserSignalHandlers) { 3673 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 3674 check_signals = false; 3675 } 3676 } 3677 } 3678 } 3679 3680 // This is the fastest way to get thread cpu time on Linux. 3681 // Returns cpu time (user+sys) for any thread, not only for current. 3682 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 3683 // It might work on 2.6.10+ with a special kernel/glibc patch. 3684 // For reference, please, see IEEE Std 1003.1-2004: 3685 // http://www.unix.org/single_unix_specification 3686 3687 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 3688 struct timespec tp; 3689 int rc = os::Linux::clock_gettime(clockid, &tp); 3690 assert(rc == 0, "clock_gettime is expected to return 0 code"); 3691 3692 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec; 3693 } 3694 3695 ///// 3696 // glibc on Linux platform uses non-documented flag 3697 // to indicate, that some special sort of signal 3698 // trampoline is used. 3699 // We will never set this flag, and we should 3700 // ignore this flag in our diagnostic 3701 #ifdef SIGNIFICANT_SIGNAL_MASK 3702 #undef SIGNIFICANT_SIGNAL_MASK 3703 #endif 3704 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 3705 3706 static const char* get_signal_handler_name(address handler, 3707 char* buf, int buflen) { 3708 int offset; 3709 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 3710 if (found) { 3711 // skip directory names 3712 const char *p1, *p2; 3713 p1 = buf; 3714 size_t len = strlen(os::file_separator()); 3715 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 3716 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 3717 } else { 3718 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 3719 } 3720 return buf; 3721 } 3722 3723 static void print_signal_handler(outputStream* st, int sig, 3724 char* buf, size_t buflen) { 3725 struct sigaction sa; 3726 3727 sigaction(sig, NULL, &sa); 3728 3729 // See comment for SIGNIFICANT_SIGNAL_MASK define 3730 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3731 3732 st->print("%s: ", os::exception_name(sig, buf, buflen)); 3733 3734 address handler = (sa.sa_flags & SA_SIGINFO) 3735 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 3736 : CAST_FROM_FN_PTR(address, sa.sa_handler); 3737 3738 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 3739 st->print("SIG_DFL"); 3740 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 3741 st->print("SIG_IGN"); 3742 } else { 3743 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 3744 } 3745 3746 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask); 3747 3748 address rh = VMError::get_resetted_sighandler(sig); 3749 // May be, handler was resetted by VMError? 3750 if(rh != NULL) { 3751 handler = rh; 3752 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 3753 } 3754 3755 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags); 3756 3757 // Check: is it our handler? 3758 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 3759 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 3760 // It is our signal handler 3761 // check for flags, reset system-used one! 3762 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 3763 st->print( 3764 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 3765 os::Linux::get_our_sigflags(sig)); 3766 } 3767 } 3768 st->cr(); 3769 } 3770 3771 3772 #define DO_SIGNAL_CHECK(sig) \ 3773 if (!sigismember(&check_signal_done, sig)) \ 3774 os::Linux::check_signal_handler(sig) 3775 3776 // This method is a periodic task to check for misbehaving JNI applications 3777 // under CheckJNI, we can add any periodic checks here 3778 3779 void os::run_periodic_checks() { 3780 3781 if (check_signals == false) return; 3782 3783 // SEGV and BUS if overridden could potentially prevent 3784 // generation of hs*.log in the event of a crash, debugging 3785 // such a case can be very challenging, so we absolutely 3786 // check the following for a good measure: 3787 DO_SIGNAL_CHECK(SIGSEGV); 3788 DO_SIGNAL_CHECK(SIGILL); 3789 DO_SIGNAL_CHECK(SIGFPE); 3790 DO_SIGNAL_CHECK(SIGBUS); 3791 DO_SIGNAL_CHECK(SIGPIPE); 3792 DO_SIGNAL_CHECK(SIGXFSZ); 3793 3794 3795 // ReduceSignalUsage allows the user to override these handlers 3796 // see comments at the very top and jvm_solaris.h 3797 if (!ReduceSignalUsage) { 3798 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 3799 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 3800 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 3801 DO_SIGNAL_CHECK(BREAK_SIGNAL); 3802 } 3803 3804 DO_SIGNAL_CHECK(SR_signum); 3805 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 3806 } 3807 3808 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 3809 3810 static os_sigaction_t os_sigaction = NULL; 3811 3812 void os::Linux::check_signal_handler(int sig) { 3813 char buf[O_BUFLEN]; 3814 address jvmHandler = NULL; 3815 3816 3817 struct sigaction act; 3818 if (os_sigaction == NULL) { 3819 // only trust the default sigaction, in case it has been interposed 3820 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 3821 if (os_sigaction == NULL) return; 3822 } 3823 3824 os_sigaction(sig, (struct sigaction*)NULL, &act); 3825 3826 3827 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3828 3829 address thisHandler = (act.sa_flags & SA_SIGINFO) 3830 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 3831 : CAST_FROM_FN_PTR(address, act.sa_handler) ; 3832 3833 3834 switch(sig) { 3835 case SIGSEGV: 3836 case SIGBUS: 3837 case SIGFPE: 3838 case SIGPIPE: 3839 case SIGILL: 3840 case SIGXFSZ: 3841 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 3842 break; 3843 3844 case SHUTDOWN1_SIGNAL: 3845 case SHUTDOWN2_SIGNAL: 3846 case SHUTDOWN3_SIGNAL: 3847 case BREAK_SIGNAL: 3848 jvmHandler = (address)user_handler(); 3849 break; 3850 3851 case INTERRUPT_SIGNAL: 3852 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 3853 break; 3854 3855 default: 3856 if (sig == SR_signum) { 3857 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 3858 } else { 3859 return; 3860 } 3861 break; 3862 } 3863 3864 if (thisHandler != jvmHandler) { 3865 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 3866 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 3867 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 3868 // No need to check this sig any longer 3869 sigaddset(&check_signal_done, sig); 3870 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 3871 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 3872 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 3873 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 3874 // No need to check this sig any longer 3875 sigaddset(&check_signal_done, sig); 3876 } 3877 3878 // Dump all the signal 3879 if (sigismember(&check_signal_done, sig)) { 3880 print_signal_handlers(tty, buf, O_BUFLEN); 3881 } 3882 } 3883 3884 extern void report_error(char* file_name, int line_no, char* title, char* format, ...); 3885 3886 extern bool signal_name(int signo, char* buf, size_t len); 3887 3888 const char* os::exception_name(int exception_code, char* buf, size_t size) { 3889 if (0 < exception_code && exception_code <= SIGRTMAX) { 3890 // signal 3891 if (!signal_name(exception_code, buf, size)) { 3892 jio_snprintf(buf, size, "SIG%d", exception_code); 3893 } 3894 return buf; 3895 } else { 3896 return NULL; 3897 } 3898 } 3899 3900 // this is called _before_ the most of global arguments have been parsed 3901 void os::init(void) { 3902 char dummy; /* used to get a guess on initial stack address */ 3903 // first_hrtime = gethrtime(); 3904 3905 // With LinuxThreads the JavaMain thread pid (primordial thread) 3906 // is different than the pid of the java launcher thread. 3907 // So, on Linux, the launcher thread pid is passed to the VM 3908 // via the sun.java.launcher.pid property. 3909 // Use this property instead of getpid() if it was correctly passed. 3910 // See bug 6351349. 3911 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid(); 3912 3913 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid(); 3914 3915 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 3916 3917 init_random(1234567); 3918 3919 ThreadCritical::initialize(); 3920 3921 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 3922 if (Linux::page_size() == -1) { 3923 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)", 3924 strerror(errno))); 3925 } 3926 init_page_sizes((size_t) Linux::page_size()); 3927 3928 Linux::initialize_system_info(); 3929 3930 // main_thread points to the aboriginal thread 3931 Linux::_main_thread = pthread_self(); 3932 3933 Linux::clock_init(); 3934 initial_time_count = os::elapsed_counter(); 3935 pthread_mutex_init(&dl_mutex, NULL); 3936 } 3937 3938 // To install functions for atexit system call 3939 extern "C" { 3940 static void perfMemory_exit_helper() { 3941 perfMemory_exit(); 3942 } 3943 } 3944 3945 // this is called _after_ the global arguments have been parsed 3946 jint os::init_2(void) 3947 { 3948 Linux::fast_thread_clock_init(); 3949 3950 // Allocate a single page and mark it as readable for safepoint polling 3951 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 3952 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" ); 3953 3954 os::set_polling_page( polling_page ); 3955 3956 #ifndef PRODUCT 3957 if(Verbose && PrintMiscellaneous) 3958 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page); 3959 #endif 3960 3961 if (!UseMembar) { 3962 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 3963 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page"); 3964 os::set_memory_serialize_page( mem_serialize_page ); 3965 3966 #ifndef PRODUCT 3967 if(Verbose && PrintMiscellaneous) 3968 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page); 3969 #endif 3970 } 3971 3972 FLAG_SET_DEFAULT(UseLargePages, os::large_page_init()); 3973 3974 // initialize suspend/resume support - must do this before signal_sets_init() 3975 if (SR_initialize() != 0) { 3976 perror("SR_initialize failed"); 3977 return JNI_ERR; 3978 } 3979 3980 Linux::signal_sets_init(); 3981 Linux::install_signal_handlers(); 3982 3983 size_t threadStackSizeInBytes = ThreadStackSize * K; 3984 if (threadStackSizeInBytes != 0 && 3985 threadStackSizeInBytes < Linux::min_stack_allowed) { 3986 tty->print_cr("\nThe stack size specified is too small, " 3987 "Specify at least %dk", 3988 Linux::min_stack_allowed / K); 3989 return JNI_ERR; 3990 } 3991 3992 // Make the stack size a multiple of the page size so that 3993 // the yellow/red zones can be guarded. 3994 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 3995 vm_page_size())); 3996 3997 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 3998 3999 Linux::libpthread_init(); 4000 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4001 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n", 4002 Linux::glibc_version(), Linux::libpthread_version(), 4003 Linux::is_floating_stack() ? "floating stack" : "fixed stack"); 4004 } 4005 4006 if (UseNUMA) { 4007 if (!Linux::libnuma_init()) { 4008 UseNUMA = false; 4009 } else { 4010 if ((Linux::numa_max_node() < 1)) { 4011 // There's only one node(they start from 0), disable NUMA. 4012 UseNUMA = false; 4013 } 4014 } 4015 if (!UseNUMA && ForceNUMA) { 4016 UseNUMA = true; 4017 } 4018 } 4019 4020 if (MaxFDLimit) { 4021 // set the number of file descriptors to max. print out error 4022 // if getrlimit/setrlimit fails but continue regardless. 4023 struct rlimit nbr_files; 4024 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4025 if (status != 0) { 4026 if (PrintMiscellaneous && (Verbose || WizardMode)) 4027 perror("os::init_2 getrlimit failed"); 4028 } else { 4029 nbr_files.rlim_cur = nbr_files.rlim_max; 4030 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4031 if (status != 0) { 4032 if (PrintMiscellaneous && (Verbose || WizardMode)) 4033 perror("os::init_2 setrlimit failed"); 4034 } 4035 } 4036 } 4037 4038 // Initialize lock used to serialize thread creation (see os::create_thread) 4039 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4040 4041 // Initialize HPI. 4042 jint hpi_result = hpi::initialize(); 4043 if (hpi_result != JNI_OK) { 4044 tty->print_cr("There was an error trying to initialize the HPI library."); 4045 return hpi_result; 4046 } 4047 4048 // at-exit methods are called in the reverse order of their registration. 4049 // atexit functions are called on return from main or as a result of a 4050 // call to exit(3C). There can be only 32 of these functions registered 4051 // and atexit() does not set errno. 4052 4053 if (PerfAllowAtExitRegistration) { 4054 // only register atexit functions if PerfAllowAtExitRegistration is set. 4055 // atexit functions can be delayed until process exit time, which 4056 // can be problematic for embedded VM situations. Embedded VMs should 4057 // call DestroyJavaVM() to assure that VM resources are released. 4058 4059 // note: perfMemory_exit_helper atexit function may be removed in 4060 // the future if the appropriate cleanup code can be added to the 4061 // VM_Exit VMOperation's doit method. 4062 if (atexit(perfMemory_exit_helper) != 0) { 4063 warning("os::init2 atexit(perfMemory_exit_helper) failed"); 4064 } 4065 } 4066 4067 // initialize thread priority policy 4068 prio_init(); 4069 4070 return JNI_OK; 4071 } 4072 4073 // this is called at the end of vm_initialization 4074 void os::init_3(void) { } 4075 4076 // Mark the polling page as unreadable 4077 void os::make_polling_page_unreadable(void) { 4078 if( !guard_memory((char*)_polling_page, Linux::page_size()) ) 4079 fatal("Could not disable polling page"); 4080 }; 4081 4082 // Mark the polling page as readable 4083 void os::make_polling_page_readable(void) { 4084 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4085 fatal("Could not enable polling page"); 4086 } 4087 }; 4088 4089 int os::active_processor_count() { 4090 // Linux doesn't yet have a (official) notion of processor sets, 4091 // so just return the number of online processors. 4092 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4093 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4094 return online_cpus; 4095 } 4096 4097 bool os::distribute_processes(uint length, uint* distribution) { 4098 // Not yet implemented. 4099 return false; 4100 } 4101 4102 bool os::bind_to_processor(uint processor_id) { 4103 // Not yet implemented. 4104 return false; 4105 } 4106 4107 /// 4108 4109 // Suspends the target using the signal mechanism and then grabs the PC before 4110 // resuming the target. Used by the flat-profiler only 4111 ExtendedPC os::get_thread_pc(Thread* thread) { 4112 // Make sure that it is called by the watcher for the VMThread 4113 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4114 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4115 4116 ExtendedPC epc; 4117 4118 OSThread* osthread = thread->osthread(); 4119 if (do_suspend(osthread)) { 4120 if (osthread->ucontext() != NULL) { 4121 epc = os::Linux::ucontext_get_pc(osthread->ucontext()); 4122 } else { 4123 // NULL context is unexpected, double-check this is the VMThread 4124 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4125 } 4126 do_resume(osthread); 4127 } 4128 // failure means pthread_kill failed for some reason - arguably this is 4129 // a fatal problem, but such problems are ignored elsewhere 4130 4131 return epc; 4132 } 4133 4134 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime) 4135 { 4136 if (is_NPTL()) { 4137 return pthread_cond_timedwait(_cond, _mutex, _abstime); 4138 } else { 4139 #ifndef IA64 4140 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control 4141 // word back to default 64bit precision if condvar is signaled. Java 4142 // wants 53bit precision. Save and restore current value. 4143 int fpu = get_fpu_control_word(); 4144 #endif // IA64 4145 int status = pthread_cond_timedwait(_cond, _mutex, _abstime); 4146 #ifndef IA64 4147 set_fpu_control_word(fpu); 4148 #endif // IA64 4149 return status; 4150 } 4151 } 4152 4153 //////////////////////////////////////////////////////////////////////////////// 4154 // debug support 4155 4156 static address same_page(address x, address y) { 4157 int page_bits = -os::vm_page_size(); 4158 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits)) 4159 return x; 4160 else if (x > y) 4161 return (address)(intptr_t(y) | ~page_bits) + 1; 4162 else 4163 return (address)(intptr_t(y) & page_bits); 4164 } 4165 4166 bool os::find(address addr, outputStream* st) { 4167 Dl_info dlinfo; 4168 memset(&dlinfo, 0, sizeof(dlinfo)); 4169 if (dladdr(addr, &dlinfo)) { 4170 st->print(PTR_FORMAT ": ", addr); 4171 if (dlinfo.dli_sname != NULL) { 4172 st->print("%s+%#x", dlinfo.dli_sname, 4173 addr - (intptr_t)dlinfo.dli_saddr); 4174 } else if (dlinfo.dli_fname) { 4175 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 4176 } else { 4177 st->print("<absolute address>"); 4178 } 4179 if (dlinfo.dli_fname) { 4180 st->print(" in %s", dlinfo.dli_fname); 4181 } 4182 if (dlinfo.dli_fbase) { 4183 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 4184 } 4185 st->cr(); 4186 4187 if (Verbose) { 4188 // decode some bytes around the PC 4189 address begin = same_page(addr-40, addr); 4190 address end = same_page(addr+40, addr); 4191 address lowest = (address) dlinfo.dli_sname; 4192 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4193 if (begin < lowest) begin = lowest; 4194 Dl_info dlinfo2; 4195 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr 4196 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) 4197 end = (address) dlinfo2.dli_saddr; 4198 Disassembler::decode(begin, end, st); 4199 } 4200 return true; 4201 } 4202 return false; 4203 } 4204 4205 //////////////////////////////////////////////////////////////////////////////// 4206 // misc 4207 4208 // This does not do anything on Linux. This is basically a hook for being 4209 // able to use structured exception handling (thread-local exception filters) 4210 // on, e.g., Win32. 4211 void 4212 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 4213 JavaCallArguments* args, Thread* thread) { 4214 f(value, method, args, thread); 4215 } 4216 4217 void os::print_statistics() { 4218 } 4219 4220 int os::message_box(const char* title, const char* message) { 4221 int i; 4222 fdStream err(defaultStream::error_fd()); 4223 for (i = 0; i < 78; i++) err.print_raw("="); 4224 err.cr(); 4225 err.print_raw_cr(title); 4226 for (i = 0; i < 78; i++) err.print_raw("-"); 4227 err.cr(); 4228 err.print_raw_cr(message); 4229 for (i = 0; i < 78; i++) err.print_raw("="); 4230 err.cr(); 4231 4232 char buf[16]; 4233 // Prevent process from exiting upon "read error" without consuming all CPU 4234 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4235 4236 return buf[0] == 'y' || buf[0] == 'Y'; 4237 } 4238 4239 int os::stat(const char *path, struct stat *sbuf) { 4240 char pathbuf[MAX_PATH]; 4241 if (strlen(path) > MAX_PATH - 1) { 4242 errno = ENAMETOOLONG; 4243 return -1; 4244 } 4245 hpi::native_path(strcpy(pathbuf, path)); 4246 return ::stat(pathbuf, sbuf); 4247 } 4248 4249 bool os::check_heap(bool force) { 4250 return true; 4251 } 4252 4253 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) { 4254 return ::vsnprintf(buf, count, format, args); 4255 } 4256 4257 // Is a (classpath) directory empty? 4258 bool os::dir_is_empty(const char* path) { 4259 DIR *dir = NULL; 4260 struct dirent *ptr; 4261 4262 dir = opendir(path); 4263 if (dir == NULL) return true; 4264 4265 /* Scan the directory */ 4266 bool result = true; 4267 char buf[sizeof(struct dirent) + MAX_PATH]; 4268 while (result && (ptr = ::readdir(dir)) != NULL) { 4269 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 4270 result = false; 4271 } 4272 } 4273 closedir(dir); 4274 return result; 4275 } 4276 4277 // create binary file, rewriting existing file if required 4278 int os::create_binary_file(const char* path, bool rewrite_existing) { 4279 int oflags = O_WRONLY | O_CREAT; 4280 if (!rewrite_existing) { 4281 oflags |= O_EXCL; 4282 } 4283 return ::open64(path, oflags, S_IREAD | S_IWRITE); 4284 } 4285 4286 // return current position of file pointer 4287 jlong os::current_file_offset(int fd) { 4288 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 4289 } 4290 4291 // move file pointer to the specified offset 4292 jlong os::seek_to_file_offset(int fd, jlong offset) { 4293 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 4294 } 4295 4296 // Map a block of memory. 4297 char* os::map_memory(int fd, const char* file_name, size_t file_offset, 4298 char *addr, size_t bytes, bool read_only, 4299 bool allow_exec) { 4300 int prot; 4301 int flags; 4302 4303 if (read_only) { 4304 prot = PROT_READ; 4305 flags = MAP_SHARED; 4306 } else { 4307 prot = PROT_READ | PROT_WRITE; 4308 flags = MAP_PRIVATE; 4309 } 4310 4311 if (allow_exec) { 4312 prot |= PROT_EXEC; 4313 } 4314 4315 if (addr != NULL) { 4316 flags |= MAP_FIXED; 4317 } 4318 4319 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 4320 fd, file_offset); 4321 if (mapped_address == MAP_FAILED) { 4322 return NULL; 4323 } 4324 return mapped_address; 4325 } 4326 4327 4328 // Remap a block of memory. 4329 char* os::remap_memory(int fd, const char* file_name, size_t file_offset, 4330 char *addr, size_t bytes, bool read_only, 4331 bool allow_exec) { 4332 // same as map_memory() on this OS 4333 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 4334 allow_exec); 4335 } 4336 4337 4338 // Unmap a block of memory. 4339 bool os::unmap_memory(char* addr, size_t bytes) { 4340 return munmap(addr, bytes) == 0; 4341 } 4342 4343 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 4344 4345 static clockid_t thread_cpu_clockid(Thread* thread) { 4346 pthread_t tid = thread->osthread()->pthread_id(); 4347 clockid_t clockid; 4348 4349 // Get thread clockid 4350 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 4351 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 4352 return clockid; 4353 } 4354 4355 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 4356 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 4357 // of a thread. 4358 // 4359 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 4360 // the fast estimate available on the platform. 4361 4362 jlong os::current_thread_cpu_time() { 4363 if (os::Linux::supports_fast_thread_cpu_time()) { 4364 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4365 } else { 4366 // return user + sys since the cost is the same 4367 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 4368 } 4369 } 4370 4371 jlong os::thread_cpu_time(Thread* thread) { 4372 // consistent with what current_thread_cpu_time() returns 4373 if (os::Linux::supports_fast_thread_cpu_time()) { 4374 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4375 } else { 4376 return slow_thread_cpu_time(thread, true /* user + sys */); 4377 } 4378 } 4379 4380 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 4381 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4382 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4383 } else { 4384 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 4385 } 4386 } 4387 4388 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4389 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4390 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4391 } else { 4392 return slow_thread_cpu_time(thread, user_sys_cpu_time); 4393 } 4394 } 4395 4396 // 4397 // -1 on error. 4398 // 4399 4400 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4401 static bool proc_pid_cpu_avail = true; 4402 static bool proc_task_unchecked = true; 4403 static const char *proc_stat_path = "/proc/%d/stat"; 4404 pid_t tid = thread->osthread()->thread_id(); 4405 int i; 4406 char *s; 4407 char stat[2048]; 4408 int statlen; 4409 char proc_name[64]; 4410 int count; 4411 long sys_time, user_time; 4412 char string[64]; 4413 char cdummy; 4414 int idummy; 4415 long ldummy; 4416 FILE *fp; 4417 4418 // We first try accessing /proc/<pid>/cpu since this is faster to 4419 // process. If this file is not present (linux kernels 2.5 and above) 4420 // then we open /proc/<pid>/stat. 4421 if ( proc_pid_cpu_avail ) { 4422 sprintf(proc_name, "/proc/%d/cpu", tid); 4423 fp = fopen(proc_name, "r"); 4424 if ( fp != NULL ) { 4425 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time); 4426 fclose(fp); 4427 if ( count != 3 ) return -1; 4428 4429 if (user_sys_cpu_time) { 4430 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4431 } else { 4432 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4433 } 4434 } 4435 else proc_pid_cpu_avail = false; 4436 } 4437 4438 // The /proc/<tid>/stat aggregates per-process usage on 4439 // new Linux kernels 2.6+ where NPTL is supported. 4440 // The /proc/self/task/<tid>/stat still has the per-thread usage. 4441 // See bug 6328462. 4442 // There can be no directory /proc/self/task on kernels 2.4 with NPTL 4443 // and possibly in some other cases, so we check its availability. 4444 if (proc_task_unchecked && os::Linux::is_NPTL()) { 4445 // This is executed only once 4446 proc_task_unchecked = false; 4447 fp = fopen("/proc/self/task", "r"); 4448 if (fp != NULL) { 4449 proc_stat_path = "/proc/self/task/%d/stat"; 4450 fclose(fp); 4451 } 4452 } 4453 4454 sprintf(proc_name, proc_stat_path, tid); 4455 fp = fopen(proc_name, "r"); 4456 if ( fp == NULL ) return -1; 4457 statlen = fread(stat, 1, 2047, fp); 4458 stat[statlen] = '\0'; 4459 fclose(fp); 4460 4461 // Skip pid and the command string. Note that we could be dealing with 4462 // weird command names, e.g. user could decide to rename java launcher 4463 // to "java 1.4.2 :)", then the stat file would look like 4464 // 1234 (java 1.4.2 :)) R ... ... 4465 // We don't really need to know the command string, just find the last 4466 // occurrence of ")" and then start parsing from there. See bug 4726580. 4467 s = strrchr(stat, ')'); 4468 i = 0; 4469 if (s == NULL ) return -1; 4470 4471 // Skip blank chars 4472 do s++; while (isspace(*s)); 4473 4474 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 4475 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 4476 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 4477 &user_time, &sys_time); 4478 if ( count != 13 ) return -1; 4479 if (user_sys_cpu_time) { 4480 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4481 } else { 4482 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4483 } 4484 } 4485 4486 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4487 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4488 info_ptr->may_skip_backward = false; // elapsed time not wall time 4489 info_ptr->may_skip_forward = false; // elapsed time not wall time 4490 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4491 } 4492 4493 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4494 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4495 info_ptr->may_skip_backward = false; // elapsed time not wall time 4496 info_ptr->may_skip_forward = false; // elapsed time not wall time 4497 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4498 } 4499 4500 bool os::is_thread_cpu_time_supported() { 4501 return true; 4502 } 4503 4504 // System loadavg support. Returns -1 if load average cannot be obtained. 4505 // Linux doesn't yet have a (official) notion of processor sets, 4506 // so just return the system wide load average. 4507 int os::loadavg(double loadavg[], int nelem) { 4508 return ::getloadavg(loadavg, nelem); 4509 } 4510 4511 void os::pause() { 4512 char filename[MAX_PATH]; 4513 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 4514 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 4515 } else { 4516 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 4517 } 4518 4519 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 4520 if (fd != -1) { 4521 struct stat buf; 4522 close(fd); 4523 while (::stat(filename, &buf) == 0) { 4524 (void)::poll(NULL, 0, 100); 4525 } 4526 } else { 4527 jio_fprintf(stderr, 4528 "Could not open pause file '%s', continuing immediately.\n", filename); 4529 } 4530 } 4531 4532 extern "C" { 4533 4534 /** 4535 * NOTE: the following code is to keep the green threads code 4536 * in the libjava.so happy. Once the green threads is removed, 4537 * these code will no longer be needed. 4538 */ 4539 int 4540 jdk_waitpid(pid_t pid, int* status, int options) { 4541 return waitpid(pid, status, options); 4542 } 4543 4544 int 4545 fork1() { 4546 return fork(); 4547 } 4548 4549 int 4550 jdk_sem_init(sem_t *sem, int pshared, unsigned int value) { 4551 return sem_init(sem, pshared, value); 4552 } 4553 4554 int 4555 jdk_sem_post(sem_t *sem) { 4556 return sem_post(sem); 4557 } 4558 4559 int 4560 jdk_sem_wait(sem_t *sem) { 4561 return sem_wait(sem); 4562 } 4563 4564 int 4565 jdk_pthread_sigmask(int how , const sigset_t* newmask, sigset_t* oldmask) { 4566 return pthread_sigmask(how , newmask, oldmask); 4567 } 4568 4569 } 4570 4571 // Refer to the comments in os_solaris.cpp park-unpark. 4572 // 4573 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 4574 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 4575 // For specifics regarding the bug see GLIBC BUGID 261237 : 4576 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 4577 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 4578 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 4579 // is used. (The simple C test-case provided in the GLIBC bug report manifests the 4580 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 4581 // and monitorenter when we're using 1-0 locking. All those operations may result in 4582 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 4583 // of libpthread avoids the problem, but isn't practical. 4584 // 4585 // Possible remedies: 4586 // 4587 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 4588 // This is palliative and probabilistic, however. If the thread is preempted 4589 // between the call to compute_abstime() and pthread_cond_timedwait(), more 4590 // than the minimum period may have passed, and the abstime may be stale (in the 4591 // past) resultin in a hang. Using this technique reduces the odds of a hang 4592 // but the JVM is still vulnerable, particularly on heavily loaded systems. 4593 // 4594 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 4595 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set 4596 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 4597 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant 4598 // thread. 4599 // 4600 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 4601 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 4602 // a timeout request to the chron thread and then blocking via pthread_cond_wait(). 4603 // This also works well. In fact it avoids kernel-level scalability impediments 4604 // on certain platforms that don't handle lots of active pthread_cond_timedwait() 4605 // timers in a graceful fashion. 4606 // 4607 // 4. When the abstime value is in the past it appears that control returns 4608 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 4609 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we 4610 // can avoid the problem by reinitializing the condvar -- by cond_destroy() 4611 // followed by cond_init() -- after all calls to pthread_cond_timedwait(). 4612 // It may be possible to avoid reinitialization by checking the return 4613 // value from pthread_cond_timedwait(). In addition to reinitializing the 4614 // condvar we must establish the invariant that cond_signal() is only called 4615 // within critical sections protected by the adjunct mutex. This prevents 4616 // cond_signal() from "seeing" a condvar that's in the midst of being 4617 // reinitialized or that is corrupt. Sadly, this invariant obviates the 4618 // desirable signal-after-unlock optimization that avoids futile context switching. 4619 // 4620 // I'm also concerned that some versions of NTPL might allocate an auxilliary 4621 // structure when a condvar is used or initialized. cond_destroy() would 4622 // release the helper structure. Our reinitialize-after-timedwait fix 4623 // put excessive stress on malloc/free and locks protecting the c-heap. 4624 // 4625 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 4626 // It may be possible to refine (4) by checking the kernel and NTPL verisons 4627 // and only enabling the work-around for vulnerable environments. 4628 4629 // utility to compute the abstime argument to timedwait: 4630 // millis is the relative timeout time 4631 // abstime will be the absolute timeout time 4632 // TODO: replace compute_abstime() with unpackTime() 4633 4634 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 4635 if (millis < 0) millis = 0; 4636 struct timeval now; 4637 int status = gettimeofday(&now, NULL); 4638 assert(status == 0, "gettimeofday"); 4639 jlong seconds = millis / 1000; 4640 millis %= 1000; 4641 if (seconds > 50000000) { // see man cond_timedwait(3T) 4642 seconds = 50000000; 4643 } 4644 abstime->tv_sec = now.tv_sec + seconds; 4645 long usec = now.tv_usec + millis * 1000; 4646 if (usec >= 1000000) { 4647 abstime->tv_sec += 1; 4648 usec -= 1000000; 4649 } 4650 abstime->tv_nsec = usec * 1000; 4651 return abstime; 4652 } 4653 4654 4655 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately. 4656 // Conceptually TryPark() should be equivalent to park(0). 4657 4658 int os::PlatformEvent::TryPark() { 4659 for (;;) { 4660 const int v = _Event ; 4661 guarantee ((v == 0) || (v == 1), "invariant") ; 4662 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ; 4663 } 4664 } 4665 4666 void os::PlatformEvent::park() { // AKA "down()" 4667 // Invariant: Only the thread associated with the Event/PlatformEvent 4668 // may call park(). 4669 // TODO: assert that _Assoc != NULL or _Assoc == Self 4670 int v ; 4671 for (;;) { 4672 v = _Event ; 4673 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 4674 } 4675 guarantee (v >= 0, "invariant") ; 4676 if (v == 0) { 4677 // Do this the hard way by blocking ... 4678 int status = pthread_mutex_lock(_mutex); 4679 assert_status(status == 0, status, "mutex_lock"); 4680 guarantee (_nParked == 0, "invariant") ; 4681 ++ _nParked ; 4682 while (_Event < 0) { 4683 status = pthread_cond_wait(_cond, _mutex); 4684 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 4685 // Treat this the same as if the wait was interrupted 4686 if (status == ETIME) { status = EINTR; } 4687 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 4688 } 4689 -- _nParked ; 4690 4691 // In theory we could move the ST of 0 into _Event past the unlock(), 4692 // but then we'd need a MEMBAR after the ST. 4693 _Event = 0 ; 4694 status = pthread_mutex_unlock(_mutex); 4695 assert_status(status == 0, status, "mutex_unlock"); 4696 } 4697 guarantee (_Event >= 0, "invariant") ; 4698 } 4699 4700 int os::PlatformEvent::park(jlong millis) { 4701 guarantee (_nParked == 0, "invariant") ; 4702 4703 int v ; 4704 for (;;) { 4705 v = _Event ; 4706 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 4707 } 4708 guarantee (v >= 0, "invariant") ; 4709 if (v != 0) return OS_OK ; 4710 4711 // We do this the hard way, by blocking the thread. 4712 // Consider enforcing a minimum timeout value. 4713 struct timespec abst; 4714 compute_abstime(&abst, millis); 4715 4716 int ret = OS_TIMEOUT; 4717 int status = pthread_mutex_lock(_mutex); 4718 assert_status(status == 0, status, "mutex_lock"); 4719 guarantee (_nParked == 0, "invariant") ; 4720 ++_nParked ; 4721 4722 // Object.wait(timo) will return because of 4723 // (a) notification 4724 // (b) timeout 4725 // (c) thread.interrupt 4726 // 4727 // Thread.interrupt and object.notify{All} both call Event::set. 4728 // That is, we treat thread.interrupt as a special case of notification. 4729 // The underlying Solaris implementation, cond_timedwait, admits 4730 // spurious/premature wakeups, but the JLS/JVM spec prevents the 4731 // JVM from making those visible to Java code. As such, we must 4732 // filter out spurious wakeups. We assume all ETIME returns are valid. 4733 // 4734 // TODO: properly differentiate simultaneous notify+interrupt. 4735 // In that case, we should propagate the notify to another waiter. 4736 4737 while (_Event < 0) { 4738 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst); 4739 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 4740 pthread_cond_destroy (_cond); 4741 pthread_cond_init (_cond, NULL) ; 4742 } 4743 assert_status(status == 0 || status == EINTR || 4744 status == ETIME || status == ETIMEDOUT, 4745 status, "cond_timedwait"); 4746 if (!FilterSpuriousWakeups) break ; // previous semantics 4747 if (status == ETIME || status == ETIMEDOUT) break ; 4748 // We consume and ignore EINTR and spurious wakeups. 4749 } 4750 --_nParked ; 4751 if (_Event >= 0) { 4752 ret = OS_OK; 4753 } 4754 _Event = 0 ; 4755 status = pthread_mutex_unlock(_mutex); 4756 assert_status(status == 0, status, "mutex_unlock"); 4757 assert (_nParked == 0, "invariant") ; 4758 return ret; 4759 } 4760 4761 void os::PlatformEvent::unpark() { 4762 int v, AnyWaiters ; 4763 for (;;) { 4764 v = _Event ; 4765 if (v > 0) { 4766 // The LD of _Event could have reordered or be satisfied 4767 // by a read-aside from this processor's write buffer. 4768 // To avoid problems execute a barrier and then 4769 // ratify the value. 4770 OrderAccess::fence() ; 4771 if (_Event == v) return ; 4772 continue ; 4773 } 4774 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ; 4775 } 4776 if (v < 0) { 4777 // Wait for the thread associated with the event to vacate 4778 int status = pthread_mutex_lock(_mutex); 4779 assert_status(status == 0, status, "mutex_lock"); 4780 AnyWaiters = _nParked ; 4781 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ; 4782 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 4783 AnyWaiters = 0 ; 4784 pthread_cond_signal (_cond); 4785 } 4786 status = pthread_mutex_unlock(_mutex); 4787 assert_status(status == 0, status, "mutex_unlock"); 4788 if (AnyWaiters != 0) { 4789 status = pthread_cond_signal(_cond); 4790 assert_status(status == 0, status, "cond_signal"); 4791 } 4792 } 4793 4794 // Note that we signal() _after dropping the lock for "immortal" Events. 4795 // This is safe and avoids a common class of futile wakeups. In rare 4796 // circumstances this can cause a thread to return prematurely from 4797 // cond_{timed}wait() but the spurious wakeup is benign and the victim will 4798 // simply re-test the condition and re-park itself. 4799 } 4800 4801 4802 // JSR166 4803 // ------------------------------------------------------- 4804 4805 /* 4806 * The solaris and linux implementations of park/unpark are fairly 4807 * conservative for now, but can be improved. They currently use a 4808 * mutex/condvar pair, plus a a count. 4809 * Park decrements count if > 0, else does a condvar wait. Unpark 4810 * sets count to 1 and signals condvar. Only one thread ever waits 4811 * on the condvar. Contention seen when trying to park implies that someone 4812 * is unparking you, so don't wait. And spurious returns are fine, so there 4813 * is no need to track notifications. 4814 */ 4815 4816 4817 #define NANOSECS_PER_SEC 1000000000 4818 #define NANOSECS_PER_MILLISEC 1000000 4819 #define MAX_SECS 100000000 4820 /* 4821 * This code is common to linux and solaris and will be moved to a 4822 * common place in dolphin. 4823 * 4824 * The passed in time value is either a relative time in nanoseconds 4825 * or an absolute time in milliseconds. Either way it has to be unpacked 4826 * into suitable seconds and nanoseconds components and stored in the 4827 * given timespec structure. 4828 * Given time is a 64-bit value and the time_t used in the timespec is only 4829 * a signed-32-bit value (except on 64-bit Linux) we have to watch for 4830 * overflow if times way in the future are given. Further on Solaris versions 4831 * prior to 10 there is a restriction (see cond_timedwait) that the specified 4832 * number of seconds, in abstime, is less than current_time + 100,000,000. 4833 * As it will be 28 years before "now + 100000000" will overflow we can 4834 * ignore overflow and just impose a hard-limit on seconds using the value 4835 * of "now + 100,000,000". This places a limit on the timeout of about 3.17 4836 * years from "now". 4837 */ 4838 4839 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 4840 assert (time > 0, "convertTime"); 4841 4842 struct timeval now; 4843 int status = gettimeofday(&now, NULL); 4844 assert(status == 0, "gettimeofday"); 4845 4846 time_t max_secs = now.tv_sec + MAX_SECS; 4847 4848 if (isAbsolute) { 4849 jlong secs = time / 1000; 4850 if (secs > max_secs) { 4851 absTime->tv_sec = max_secs; 4852 } 4853 else { 4854 absTime->tv_sec = secs; 4855 } 4856 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 4857 } 4858 else { 4859 jlong secs = time / NANOSECS_PER_SEC; 4860 if (secs >= MAX_SECS) { 4861 absTime->tv_sec = max_secs; 4862 absTime->tv_nsec = 0; 4863 } 4864 else { 4865 absTime->tv_sec = now.tv_sec + secs; 4866 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 4867 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 4868 absTime->tv_nsec -= NANOSECS_PER_SEC; 4869 ++absTime->tv_sec; // note: this must be <= max_secs 4870 } 4871 } 4872 } 4873 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 4874 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 4875 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 4876 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 4877 } 4878 4879 void Parker::park(bool isAbsolute, jlong time) { 4880 // Optional fast-path check: 4881 // Return immediately if a permit is available. 4882 if (_counter > 0) { 4883 _counter = 0 ; 4884 OrderAccess::fence(); 4885 return ; 4886 } 4887 4888 Thread* thread = Thread::current(); 4889 assert(thread->is_Java_thread(), "Must be JavaThread"); 4890 JavaThread *jt = (JavaThread *)thread; 4891 4892 // Optional optimization -- avoid state transitions if there's an interrupt pending. 4893 // Check interrupt before trying to wait 4894 if (Thread::is_interrupted(thread, false)) { 4895 return; 4896 } 4897 4898 // Next, demultiplex/decode time arguments 4899 timespec absTime; 4900 if (time < 0) { // don't wait at all 4901 return; 4902 } 4903 if (time > 0) { 4904 unpackTime(&absTime, isAbsolute, time); 4905 } 4906 4907 4908 // Enter safepoint region 4909 // Beware of deadlocks such as 6317397. 4910 // The per-thread Parker:: mutex is a classic leaf-lock. 4911 // In particular a thread must never block on the Threads_lock while 4912 // holding the Parker:: mutex. If safepoints are pending both the 4913 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 4914 ThreadBlockInVM tbivm(jt); 4915 4916 // Don't wait if cannot get lock since interference arises from 4917 // unblocking. Also. check interrupt before trying wait 4918 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 4919 return; 4920 } 4921 4922 int status ; 4923 if (_counter > 0) { // no wait needed 4924 _counter = 0; 4925 status = pthread_mutex_unlock(_mutex); 4926 assert (status == 0, "invariant") ; 4927 OrderAccess::fence(); 4928 return; 4929 } 4930 4931 #ifdef ASSERT 4932 // Don't catch signals while blocked; let the running threads have the signals. 4933 // (This allows a debugger to break into the running thread.) 4934 sigset_t oldsigs; 4935 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 4936 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 4937 #endif 4938 4939 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 4940 jt->set_suspend_equivalent(); 4941 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 4942 4943 if (time == 0) { 4944 status = pthread_cond_wait (_cond, _mutex) ; 4945 } else { 4946 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ; 4947 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 4948 pthread_cond_destroy (_cond) ; 4949 pthread_cond_init (_cond, NULL); 4950 } 4951 } 4952 assert_status(status == 0 || status == EINTR || 4953 status == ETIME || status == ETIMEDOUT, 4954 status, "cond_timedwait"); 4955 4956 #ifdef ASSERT 4957 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 4958 #endif 4959 4960 _counter = 0 ; 4961 status = pthread_mutex_unlock(_mutex) ; 4962 assert_status(status == 0, status, "invariant") ; 4963 // If externally suspended while waiting, re-suspend 4964 if (jt->handle_special_suspend_equivalent_condition()) { 4965 jt->java_suspend_self(); 4966 } 4967 4968 OrderAccess::fence(); 4969 } 4970 4971 void Parker::unpark() { 4972 int s, status ; 4973 status = pthread_mutex_lock(_mutex); 4974 assert (status == 0, "invariant") ; 4975 s = _counter; 4976 _counter = 1; 4977 if (s < 1) { 4978 if (WorkAroundNPTLTimedWaitHang) { 4979 status = pthread_cond_signal (_cond) ; 4980 assert (status == 0, "invariant") ; 4981 status = pthread_mutex_unlock(_mutex); 4982 assert (status == 0, "invariant") ; 4983 } else { 4984 status = pthread_mutex_unlock(_mutex); 4985 assert (status == 0, "invariant") ; 4986 status = pthread_cond_signal (_cond) ; 4987 assert (status == 0, "invariant") ; 4988 } 4989 } else { 4990 pthread_mutex_unlock(_mutex); 4991 assert (status == 0, "invariant") ; 4992 } 4993 } 4994 4995 4996 extern char** environ; 4997 4998 #ifndef __NR_fork 4999 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) 5000 #endif 5001 5002 #ifndef __NR_execve 5003 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) 5004 #endif 5005 5006 // Run the specified command in a separate process. Return its exit value, 5007 // or -1 on failure (e.g. can't fork a new process). 5008 // Unlike system(), this function can be called from signal handler. It 5009 // doesn't block SIGINT et al. 5010 int os::fork_and_exec(char* cmd) { 5011 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5012 5013 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run 5014 // pthread_atfork handlers and reset pthread library. All we need is a 5015 // separate process to execve. Make a direct syscall to fork process. 5016 // On IA64 there's no fork syscall, we have to use fork() and hope for 5017 // the best... 5018 pid_t pid = NOT_IA64(syscall(__NR_fork);) 5019 IA64_ONLY(fork();) 5020 5021 if (pid < 0) { 5022 // fork failed 5023 return -1; 5024 5025 } else if (pid == 0) { 5026 // child process 5027 5028 // execve() in LinuxThreads will call pthread_kill_other_threads_np() 5029 // first to kill every thread on the thread list. Because this list is 5030 // not reset by fork() (see notes above), execve() will instead kill 5031 // every thread in the parent process. We know this is the only thread 5032 // in the new process, so make a system call directly. 5033 // IA64 should use normal execve() from glibc to match the glibc fork() 5034 // above. 5035 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);) 5036 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);) 5037 5038 // execve failed 5039 _exit(-1); 5040 5041 } else { 5042 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5043 // care about the actual exit code, for now. 5044 5045 int status; 5046 5047 // Wait for the child process to exit. This returns immediately if 5048 // the child has already exited. */ 5049 while (waitpid(pid, &status, 0) < 0) { 5050 switch (errno) { 5051 case ECHILD: return 0; 5052 case EINTR: break; 5053 default: return -1; 5054 } 5055 } 5056 5057 if (WIFEXITED(status)) { 5058 // The child exited normally; get its exit code. 5059 return WEXITSTATUS(status); 5060 } else if (WIFSIGNALED(status)) { 5061 // The child exited because of a signal 5062 // The best value to return is 0x80 + signal number, 5063 // because that is what all Unix shells do, and because 5064 // it allows callers to distinguish between process exit and 5065 // process death by signal. 5066 return 0x80 + WTERMSIG(status); 5067 } else { 5068 // Unknown exit code; pass it through 5069 return status; 5070 } 5071 } 5072 } 5073 5074 // is_headless_jre() 5075 // 5076 // Test for the existence of libmawt in motif21 or xawt directories 5077 // in order to report if we are running in a headless jre 5078 // 5079 bool os::is_headless_jre() { 5080 struct stat statbuf; 5081 char buf[MAXPATHLEN]; 5082 char libmawtpath[MAXPATHLEN]; 5083 const char *xawtstr = "/xawt/libmawt.so"; 5084 const char *motifstr = "/motif21/libmawt.so"; 5085 char *p; 5086 5087 // Get path to libjvm.so 5088 os::jvm_path(buf, sizeof(buf)); 5089 5090 // Get rid of libjvm.so 5091 p = strrchr(buf, '/'); 5092 if (p == NULL) return false; 5093 else *p = '\0'; 5094 5095 // Get rid of client or server 5096 p = strrchr(buf, '/'); 5097 if (p == NULL) return false; 5098 else *p = '\0'; 5099 5100 // check xawt/libmawt.so 5101 strcpy(libmawtpath, buf); 5102 strcat(libmawtpath, xawtstr); 5103 if (::stat(libmawtpath, &statbuf) == 0) return false; 5104 5105 // check motif21/libmawt.so 5106 strcpy(libmawtpath, buf); 5107 strcat(libmawtpath, motifstr); 5108 if (::stat(libmawtpath, &statbuf) == 0) return false; 5109 5110 return true; 5111 } 5112