1 /* 2 * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 # define __STDC_FORMAT_MACROS 26 27 // no precompiled headers 28 #include "classfile/classLoader.hpp" 29 #include "classfile/systemDictionary.hpp" 30 #include "classfile/vmSymbols.hpp" 31 #include "code/icBuffer.hpp" 32 #include "code/vtableStubs.hpp" 33 #include "compiler/compileBroker.hpp" 34 #include "interpreter/interpreter.hpp" 35 #include "jvm_linux.h" 36 #include "memory/allocation.inline.hpp" 37 #include "memory/filemap.hpp" 38 #include "mutex_linux.inline.hpp" 39 #include "oops/oop.inline.hpp" 40 #include "os_share_linux.hpp" 41 #include "prims/jniFastGetField.hpp" 42 #include "prims/jvm.h" 43 #include "prims/jvm_misc.hpp" 44 #include "runtime/arguments.hpp" 45 #include "runtime/extendedPC.hpp" 46 #include "runtime/globals.hpp" 47 #include "runtime/interfaceSupport.hpp" 48 #include "runtime/java.hpp" 49 #include "runtime/javaCalls.hpp" 50 #include "runtime/mutexLocker.hpp" 51 #include "runtime/objectMonitor.hpp" 52 #include "runtime/osThread.hpp" 53 #include "runtime/perfMemory.hpp" 54 #include "runtime/sharedRuntime.hpp" 55 #include "runtime/statSampler.hpp" 56 #include "runtime/stubRoutines.hpp" 57 #include "runtime/threadCritical.hpp" 58 #include "runtime/timer.hpp" 59 #include "services/attachListener.hpp" 60 #include "services/runtimeService.hpp" 61 #include "thread_linux.inline.hpp" 62 #include "utilities/decoder.hpp" 63 #include "utilities/defaultStream.hpp" 64 #include "utilities/events.hpp" 65 #include "utilities/growableArray.hpp" 66 #include "utilities/vmError.hpp" 67 #ifdef TARGET_ARCH_x86 68 # include "assembler_x86.inline.hpp" 69 # include "nativeInst_x86.hpp" 70 #endif 71 #ifdef TARGET_ARCH_sparc 72 # include "assembler_sparc.inline.hpp" 73 # include "nativeInst_sparc.hpp" 74 #endif 75 #ifdef TARGET_ARCH_zero 76 # include "assembler_zero.inline.hpp" 77 # include "nativeInst_zero.hpp" 78 #endif 79 #ifdef TARGET_ARCH_arm 80 # include "assembler_arm.inline.hpp" 81 # include "nativeInst_arm.hpp" 82 #endif 83 #ifdef TARGET_ARCH_ppc 84 # include "assembler_ppc.inline.hpp" 85 # include "nativeInst_ppc.hpp" 86 #endif 87 #ifdef COMPILER1 88 #include "c1/c1_Runtime1.hpp" 89 #endif 90 #ifdef COMPILER2 91 #include "opto/runtime.hpp" 92 #endif 93 94 // put OS-includes here 95 # include <sys/types.h> 96 # include <sys/mman.h> 97 # include <sys/stat.h> 98 # include <sys/select.h> 99 # include <pthread.h> 100 # include <signal.h> 101 # include <errno.h> 102 # include <dlfcn.h> 103 # include <stdio.h> 104 # include <unistd.h> 105 # include <sys/resource.h> 106 # include <pthread.h> 107 # include <sys/stat.h> 108 # include <sys/time.h> 109 # include <sys/times.h> 110 # include <sys/utsname.h> 111 # include <sys/socket.h> 112 # include <sys/wait.h> 113 # include <pwd.h> 114 # include <poll.h> 115 # include <semaphore.h> 116 # include <fcntl.h> 117 # include <string.h> 118 # include <syscall.h> 119 # include <sys/sysinfo.h> 120 # include <gnu/libc-version.h> 121 # include <sys/ipc.h> 122 # include <sys/shm.h> 123 # include <link.h> 124 # include <stdint.h> 125 # include <inttypes.h> 126 # include <sys/ioctl.h> 127 128 #define MAX_PATH (2 * K) 129 130 // for timer info max values which include all bits 131 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 132 #define SEC_IN_NANOSECS 1000000000LL 133 134 #define LARGEPAGES_BIT (1 << 6) 135 //////////////////////////////////////////////////////////////////////////////// 136 // global variables 137 julong os::Linux::_physical_memory = 0; 138 139 address os::Linux::_initial_thread_stack_bottom = NULL; 140 uintptr_t os::Linux::_initial_thread_stack_size = 0; 141 142 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 143 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 144 Mutex* os::Linux::_createThread_lock = NULL; 145 pthread_t os::Linux::_main_thread; 146 int os::Linux::_page_size = -1; 147 bool os::Linux::_is_floating_stack = false; 148 bool os::Linux::_is_NPTL = false; 149 bool os::Linux::_supports_fast_thread_cpu_time = false; 150 const char * os::Linux::_glibc_version = NULL; 151 const char * os::Linux::_libpthread_version = NULL; 152 153 static jlong initial_time_count=0; 154 155 static int clock_tics_per_sec = 100; 156 157 // For diagnostics to print a message once. see run_periodic_checks 158 static sigset_t check_signal_done; 159 static bool check_signals = true;; 160 161 static pid_t _initial_pid = 0; 162 163 /* Signal number used to suspend/resume a thread */ 164 165 /* do not use any signal number less than SIGSEGV, see 4355769 */ 166 static int SR_signum = SIGUSR2; 167 sigset_t SR_sigset; 168 169 /* Used to protect dlsym() calls */ 170 static pthread_mutex_t dl_mutex; 171 172 //////////////////////////////////////////////////////////////////////////////// 173 // utility functions 174 175 static int SR_initialize(); 176 static int SR_finalize(); 177 178 julong os::available_memory() { 179 return Linux::available_memory(); 180 } 181 182 julong os::Linux::available_memory() { 183 // values in struct sysinfo are "unsigned long" 184 struct sysinfo si; 185 sysinfo(&si); 186 187 return (julong)si.freeram * si.mem_unit; 188 } 189 190 julong os::physical_memory() { 191 return Linux::physical_memory(); 192 } 193 194 julong os::allocatable_physical_memory(julong size) { 195 #ifdef _LP64 196 return size; 197 #else 198 julong result = MIN2(size, (julong)3800*M); 199 if (!is_allocatable(result)) { 200 // See comments under solaris for alignment considerations 201 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size(); 202 result = MIN2(size, reasonable_size); 203 } 204 return result; 205 #endif // _LP64 206 } 207 208 //////////////////////////////////////////////////////////////////////////////// 209 // environment support 210 211 bool os::getenv(const char* name, char* buf, int len) { 212 const char* val = ::getenv(name); 213 if (val != NULL && strlen(val) < (size_t)len) { 214 strcpy(buf, val); 215 return true; 216 } 217 if (len > 0) buf[0] = 0; // return a null string 218 return false; 219 } 220 221 222 // Return true if user is running as root. 223 224 bool os::have_special_privileges() { 225 static bool init = false; 226 static bool privileges = false; 227 if (!init) { 228 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 229 init = true; 230 } 231 return privileges; 232 } 233 234 235 #ifndef SYS_gettid 236 // i386: 224, ia64: 1105, amd64: 186, sparc 143 237 #ifdef __ia64__ 238 #define SYS_gettid 1105 239 #elif __i386__ 240 #define SYS_gettid 224 241 #elif __amd64__ 242 #define SYS_gettid 186 243 #elif __sparc__ 244 #define SYS_gettid 143 245 #else 246 #error define gettid for the arch 247 #endif 248 #endif 249 250 // Cpu architecture string 251 #if defined(ZERO) 252 static char cpu_arch[] = ZERO_LIBARCH; 253 #elif defined(IA64) 254 static char cpu_arch[] = "ia64"; 255 #elif defined(IA32) 256 static char cpu_arch[] = "i386"; 257 #elif defined(AMD64) 258 static char cpu_arch[] = "amd64"; 259 #elif defined(ARM) 260 static char cpu_arch[] = "arm"; 261 #elif defined(PPC) 262 static char cpu_arch[] = "ppc"; 263 #elif defined(SPARC) 264 # ifdef _LP64 265 static char cpu_arch[] = "sparcv9"; 266 # else 267 static char cpu_arch[] = "sparc"; 268 # endif 269 #else 270 #error Add appropriate cpu_arch setting 271 #endif 272 273 274 // pid_t gettid() 275 // 276 // Returns the kernel thread id of the currently running thread. Kernel 277 // thread id is used to access /proc. 278 // 279 // (Note that getpid() on LinuxThreads returns kernel thread id too; but 280 // on NPTL, it returns the same pid for all threads, as required by POSIX.) 281 // 282 pid_t os::Linux::gettid() { 283 int rslt = syscall(SYS_gettid); 284 if (rslt == -1) { 285 // old kernel, no NPTL support 286 return getpid(); 287 } else { 288 return (pid_t)rslt; 289 } 290 } 291 292 // Most versions of linux have a bug where the number of processors are 293 // determined by looking at the /proc file system. In a chroot environment, 294 // the system call returns 1. This causes the VM to act as if it is 295 // a single processor and elide locking (see is_MP() call). 296 static bool unsafe_chroot_detected = false; 297 static const char *unstable_chroot_error = "/proc file system not found.\n" 298 "Java may be unstable running multithreaded in a chroot " 299 "environment on Linux when /proc filesystem is not mounted."; 300 301 void os::Linux::initialize_system_info() { 302 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 303 if (processor_count() == 1) { 304 pid_t pid = os::Linux::gettid(); 305 char fname[32]; 306 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 307 FILE *fp = fopen(fname, "r"); 308 if (fp == NULL) { 309 unsafe_chroot_detected = true; 310 } else { 311 fclose(fp); 312 } 313 } 314 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 315 assert(processor_count() > 0, "linux error"); 316 } 317 318 void os::init_system_properties_values() { 319 // char arch[12]; 320 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch)); 321 322 // The next steps are taken in the product version: 323 // 324 // Obtain the JAVA_HOME value from the location of libjvm[_g].so. 325 // This library should be located at: 326 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so. 327 // 328 // If "/jre/lib/" appears at the right place in the path, then we 329 // assume libjvm[_g].so is installed in a JDK and we use this path. 330 // 331 // Otherwise exit with message: "Could not create the Java virtual machine." 332 // 333 // The following extra steps are taken in the debugging version: 334 // 335 // If "/jre/lib/" does NOT appear at the right place in the path 336 // instead of exit check for $JAVA_HOME environment variable. 337 // 338 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 339 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so 340 // it looks like libjvm[_g].so is installed there 341 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so. 342 // 343 // Otherwise exit. 344 // 345 // Important note: if the location of libjvm.so changes this 346 // code needs to be changed accordingly. 347 348 // The next few definitions allow the code to be verbatim: 349 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n)) 350 #define getenv(n) ::getenv(n) 351 352 /* 353 * See ld(1): 354 * The linker uses the following search paths to locate required 355 * shared libraries: 356 * 1: ... 357 * ... 358 * 7: The default directories, normally /lib and /usr/lib. 359 */ 360 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 361 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 362 #else 363 #define DEFAULT_LIBPATH "/lib:/usr/lib" 364 #endif 365 366 #define EXTENSIONS_DIR "/lib/ext" 367 #define ENDORSED_DIR "/lib/endorsed" 368 #define REG_DIR "/usr/java/packages" 369 370 { 371 /* sysclasspath, java_home, dll_dir */ 372 { 373 char *home_path; 374 char *dll_path; 375 char *pslash; 376 char buf[MAXPATHLEN]; 377 os::jvm_path(buf, sizeof(buf)); 378 379 // Found the full path to libjvm.so. 380 // Now cut the path to <java_home>/jre if we can. 381 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */ 382 pslash = strrchr(buf, '/'); 383 if (pslash != NULL) 384 *pslash = '\0'; /* get rid of /{client|server|hotspot} */ 385 dll_path = malloc(strlen(buf) + 1); 386 if (dll_path == NULL) 387 return; 388 strcpy(dll_path, buf); 389 Arguments::set_dll_dir(dll_path); 390 391 if (pslash != NULL) { 392 pslash = strrchr(buf, '/'); 393 if (pslash != NULL) { 394 *pslash = '\0'; /* get rid of /<arch> */ 395 pslash = strrchr(buf, '/'); 396 if (pslash != NULL) 397 *pslash = '\0'; /* get rid of /lib */ 398 } 399 } 400 401 home_path = malloc(strlen(buf) + 1); 402 if (home_path == NULL) 403 return; 404 strcpy(home_path, buf); 405 Arguments::set_java_home(home_path); 406 407 if (!set_boot_path('/', ':')) 408 return; 409 } 410 411 /* 412 * Where to look for native libraries 413 * 414 * Note: Due to a legacy implementation, most of the library path 415 * is set in the launcher. This was to accomodate linking restrictions 416 * on legacy Linux implementations (which are no longer supported). 417 * Eventually, all the library path setting will be done here. 418 * 419 * However, to prevent the proliferation of improperly built native 420 * libraries, the new path component /usr/java/packages is added here. 421 * Eventually, all the library path setting will be done here. 422 */ 423 { 424 char *ld_library_path; 425 426 /* 427 * Construct the invariant part of ld_library_path. Note that the 428 * space for the colon and the trailing null are provided by the 429 * nulls included by the sizeof operator (so actually we allocate 430 * a byte more than necessary). 431 */ 432 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") + 433 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH)); 434 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch); 435 436 /* 437 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It 438 * should always exist (until the legacy problem cited above is 439 * addressed). 440 */ 441 char *v = getenv("LD_LIBRARY_PATH"); 442 if (v != NULL) { 443 char *t = ld_library_path; 444 /* That's +1 for the colon and +1 for the trailing '\0' */ 445 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1); 446 sprintf(ld_library_path, "%s:%s", v, t); 447 } 448 Arguments::set_library_path(ld_library_path); 449 } 450 451 /* 452 * Extensions directories. 453 * 454 * Note that the space for the colon and the trailing null are provided 455 * by the nulls included by the sizeof operator (so actually one byte more 456 * than necessary is allocated). 457 */ 458 { 459 char *buf = malloc(strlen(Arguments::get_java_home()) + 460 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR)); 461 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR, 462 Arguments::get_java_home()); 463 Arguments::set_ext_dirs(buf); 464 } 465 466 /* Endorsed standards default directory. */ 467 { 468 char * buf; 469 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR)); 470 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home()); 471 Arguments::set_endorsed_dirs(buf); 472 } 473 } 474 475 #undef malloc 476 #undef getenv 477 #undef EXTENSIONS_DIR 478 #undef ENDORSED_DIR 479 480 // Done 481 return; 482 } 483 484 //////////////////////////////////////////////////////////////////////////////// 485 // breakpoint support 486 487 void os::breakpoint() { 488 BREAKPOINT; 489 } 490 491 extern "C" void breakpoint() { 492 // use debugger to set breakpoint here 493 } 494 495 //////////////////////////////////////////////////////////////////////////////// 496 // signal support 497 498 debug_only(static bool signal_sets_initialized = false); 499 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 500 501 bool os::Linux::is_sig_ignored(int sig) { 502 struct sigaction oact; 503 sigaction(sig, (struct sigaction*)NULL, &oact); 504 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 505 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 506 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) 507 return true; 508 else 509 return false; 510 } 511 512 void os::Linux::signal_sets_init() { 513 // Should also have an assertion stating we are still single-threaded. 514 assert(!signal_sets_initialized, "Already initialized"); 515 // Fill in signals that are necessarily unblocked for all threads in 516 // the VM. Currently, we unblock the following signals: 517 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 518 // by -Xrs (=ReduceSignalUsage)); 519 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 520 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 521 // the dispositions or masks wrt these signals. 522 // Programs embedding the VM that want to use the above signals for their 523 // own purposes must, at this time, use the "-Xrs" option to prevent 524 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 525 // (See bug 4345157, and other related bugs). 526 // In reality, though, unblocking these signals is really a nop, since 527 // these signals are not blocked by default. 528 sigemptyset(&unblocked_sigs); 529 sigemptyset(&allowdebug_blocked_sigs); 530 sigaddset(&unblocked_sigs, SIGILL); 531 sigaddset(&unblocked_sigs, SIGSEGV); 532 sigaddset(&unblocked_sigs, SIGBUS); 533 sigaddset(&unblocked_sigs, SIGFPE); 534 sigaddset(&unblocked_sigs, SR_signum); 535 536 if (!ReduceSignalUsage) { 537 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 538 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 539 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 540 } 541 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 542 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 543 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 544 } 545 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 546 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 547 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 548 } 549 } 550 // Fill in signals that are blocked by all but the VM thread. 551 sigemptyset(&vm_sigs); 552 if (!ReduceSignalUsage) 553 sigaddset(&vm_sigs, BREAK_SIGNAL); 554 debug_only(signal_sets_initialized = true); 555 556 } 557 558 // These are signals that are unblocked while a thread is running Java. 559 // (For some reason, they get blocked by default.) 560 sigset_t* os::Linux::unblocked_signals() { 561 assert(signal_sets_initialized, "Not initialized"); 562 return &unblocked_sigs; 563 } 564 565 // These are the signals that are blocked while a (non-VM) thread is 566 // running Java. Only the VM thread handles these signals. 567 sigset_t* os::Linux::vm_signals() { 568 assert(signal_sets_initialized, "Not initialized"); 569 return &vm_sigs; 570 } 571 572 // These are signals that are blocked during cond_wait to allow debugger in 573 sigset_t* os::Linux::allowdebug_blocked_signals() { 574 assert(signal_sets_initialized, "Not initialized"); 575 return &allowdebug_blocked_sigs; 576 } 577 578 void os::Linux::hotspot_sigmask(Thread* thread) { 579 580 //Save caller's signal mask before setting VM signal mask 581 sigset_t caller_sigmask; 582 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 583 584 OSThread* osthread = thread->osthread(); 585 osthread->set_caller_sigmask(caller_sigmask); 586 587 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 588 589 if (!ReduceSignalUsage) { 590 if (thread->is_VM_thread()) { 591 // Only the VM thread handles BREAK_SIGNAL ... 592 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 593 } else { 594 // ... all other threads block BREAK_SIGNAL 595 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 596 } 597 } 598 } 599 600 ////////////////////////////////////////////////////////////////////////////// 601 // detecting pthread library 602 603 void os::Linux::libpthread_init() { 604 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION 605 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a 606 // generic name for earlier versions. 607 // Define macros here so we can build HotSpot on old systems. 608 # ifndef _CS_GNU_LIBC_VERSION 609 # define _CS_GNU_LIBC_VERSION 2 610 # endif 611 # ifndef _CS_GNU_LIBPTHREAD_VERSION 612 # define _CS_GNU_LIBPTHREAD_VERSION 3 613 # endif 614 615 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 616 if (n > 0) { 617 char *str = (char *)malloc(n); 618 confstr(_CS_GNU_LIBC_VERSION, str, n); 619 os::Linux::set_glibc_version(str); 620 } else { 621 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version() 622 static char _gnu_libc_version[32]; 623 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version), 624 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release()); 625 os::Linux::set_glibc_version(_gnu_libc_version); 626 } 627 628 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 629 if (n > 0) { 630 char *str = (char *)malloc(n); 631 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 632 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells 633 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this 634 // is the case. LinuxThreads has a hard limit on max number of threads. 635 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value. 636 // On the other hand, NPTL does not have such a limit, sysconf() 637 // will return -1 and errno is not changed. Check if it is really NPTL. 638 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 && 639 strstr(str, "NPTL") && 640 sysconf(_SC_THREAD_THREADS_MAX) > 0) { 641 free(str); 642 os::Linux::set_libpthread_version("linuxthreads"); 643 } else { 644 os::Linux::set_libpthread_version(str); 645 } 646 } else { 647 // glibc before 2.3.2 only has LinuxThreads. 648 os::Linux::set_libpthread_version("linuxthreads"); 649 } 650 651 if (strstr(libpthread_version(), "NPTL")) { 652 os::Linux::set_is_NPTL(); 653 } else { 654 os::Linux::set_is_LinuxThreads(); 655 } 656 657 // LinuxThreads have two flavors: floating-stack mode, which allows variable 658 // stack size; and fixed-stack mode. NPTL is always floating-stack. 659 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) { 660 os::Linux::set_is_floating_stack(); 661 } 662 } 663 664 ///////////////////////////////////////////////////////////////////////////// 665 // thread stack 666 667 // Force Linux kernel to expand current thread stack. If "bottom" is close 668 // to the stack guard, caller should block all signals. 669 // 670 // MAP_GROWSDOWN: 671 // A special mmap() flag that is used to implement thread stacks. It tells 672 // kernel that the memory region should extend downwards when needed. This 673 // allows early versions of LinuxThreads to only mmap the first few pages 674 // when creating a new thread. Linux kernel will automatically expand thread 675 // stack as needed (on page faults). 676 // 677 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 678 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 679 // region, it's hard to tell if the fault is due to a legitimate stack 680 // access or because of reading/writing non-exist memory (e.g. buffer 681 // overrun). As a rule, if the fault happens below current stack pointer, 682 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 683 // application (see Linux kernel fault.c). 684 // 685 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 686 // stack overflow detection. 687 // 688 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 689 // not use this flag. However, the stack of initial thread is not created 690 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though 691 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack 692 // and then attach the thread to JVM. 693 // 694 // To get around the problem and allow stack banging on Linux, we need to 695 // manually expand thread stack after receiving the SIGSEGV. 696 // 697 // There are two ways to expand thread stack to address "bottom", we used 698 // both of them in JVM before 1.5: 699 // 1. adjust stack pointer first so that it is below "bottom", and then 700 // touch "bottom" 701 // 2. mmap() the page in question 702 // 703 // Now alternate signal stack is gone, it's harder to use 2. For instance, 704 // if current sp is already near the lower end of page 101, and we need to 705 // call mmap() to map page 100, it is possible that part of the mmap() frame 706 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 707 // That will destroy the mmap() frame and cause VM to crash. 708 // 709 // The following code works by adjusting sp first, then accessing the "bottom" 710 // page to force a page fault. Linux kernel will then automatically expand the 711 // stack mapping. 712 // 713 // _expand_stack_to() assumes its frame size is less than page size, which 714 // should always be true if the function is not inlined. 715 716 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 717 #define NOINLINE 718 #else 719 #define NOINLINE __attribute__ ((noinline)) 720 #endif 721 722 static void _expand_stack_to(address bottom) NOINLINE; 723 724 static void _expand_stack_to(address bottom) { 725 address sp; 726 size_t size; 727 volatile char *p; 728 729 // Adjust bottom to point to the largest address within the same page, it 730 // gives us a one-page buffer if alloca() allocates slightly more memory. 731 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 732 bottom += os::Linux::page_size() - 1; 733 734 // sp might be slightly above current stack pointer; if that's the case, we 735 // will alloca() a little more space than necessary, which is OK. Don't use 736 // os::current_stack_pointer(), as its result can be slightly below current 737 // stack pointer, causing us to not alloca enough to reach "bottom". 738 sp = (address)&sp; 739 740 if (sp > bottom) { 741 size = sp - bottom; 742 p = (volatile char *)alloca(size); 743 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 744 p[0] = '\0'; 745 } 746 } 747 748 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 749 assert(t!=NULL, "just checking"); 750 assert(t->osthread()->expanding_stack(), "expand should be set"); 751 assert(t->stack_base() != NULL, "stack_base was not initialized"); 752 753 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 754 sigset_t mask_all, old_sigset; 755 sigfillset(&mask_all); 756 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 757 _expand_stack_to(addr); 758 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 759 return true; 760 } 761 return false; 762 } 763 764 ////////////////////////////////////////////////////////////////////////////// 765 // create new thread 766 767 static address highest_vm_reserved_address(); 768 769 // check if it's safe to start a new thread 770 static bool _thread_safety_check(Thread* thread) { 771 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) { 772 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat) 773 // Heap is mmap'ed at lower end of memory space. Thread stacks are 774 // allocated (MAP_FIXED) from high address space. Every thread stack 775 // occupies a fixed size slot (usually 2Mbytes, but user can change 776 // it to other values if they rebuild LinuxThreads). 777 // 778 // Problem with MAP_FIXED is that mmap() can still succeed even part of 779 // the memory region has already been mmap'ed. That means if we have too 780 // many threads and/or very large heap, eventually thread stack will 781 // collide with heap. 782 // 783 // Here we try to prevent heap/stack collision by comparing current 784 // stack bottom with the highest address that has been mmap'ed by JVM 785 // plus a safety margin for memory maps created by native code. 786 // 787 // This feature can be disabled by setting ThreadSafetyMargin to 0 788 // 789 if (ThreadSafetyMargin > 0) { 790 address stack_bottom = os::current_stack_base() - os::current_stack_size(); 791 792 // not safe if our stack extends below the safety margin 793 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address(); 794 } else { 795 return true; 796 } 797 } else { 798 // Floating stack LinuxThreads or NPTL: 799 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When 800 // there's not enough space left, pthread_create() will fail. If we come 801 // here, that means enough space has been reserved for stack. 802 return true; 803 } 804 } 805 806 // Thread start routine for all newly created threads 807 static void *java_start(Thread *thread) { 808 // Try to randomize the cache line index of hot stack frames. 809 // This helps when threads of the same stack traces evict each other's 810 // cache lines. The threads can be either from the same JVM instance, or 811 // from different JVM instances. The benefit is especially true for 812 // processors with hyperthreading technology. 813 static int counter = 0; 814 int pid = os::current_process_id(); 815 alloca(((pid ^ counter++) & 7) * 128); 816 817 ThreadLocalStorage::set_thread(thread); 818 819 OSThread* osthread = thread->osthread(); 820 Monitor* sync = osthread->startThread_lock(); 821 822 // non floating stack LinuxThreads needs extra check, see above 823 if (!_thread_safety_check(thread)) { 824 // notify parent thread 825 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 826 osthread->set_state(ZOMBIE); 827 sync->notify_all(); 828 return NULL; 829 } 830 831 // thread_id is kernel thread id (similar to Solaris LWP id) 832 osthread->set_thread_id(os::Linux::gettid()); 833 834 if (UseNUMA) { 835 int lgrp_id = os::numa_get_group_id(); 836 if (lgrp_id != -1) { 837 thread->set_lgrp_id(lgrp_id); 838 } 839 } 840 // initialize signal mask for this thread 841 os::Linux::hotspot_sigmask(thread); 842 843 // initialize floating point control register 844 os::Linux::init_thread_fpu_state(); 845 846 // handshaking with parent thread 847 { 848 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 849 850 // notify parent thread 851 osthread->set_state(INITIALIZED); 852 sync->notify_all(); 853 854 // wait until os::start_thread() 855 while (osthread->get_state() == INITIALIZED) { 856 sync->wait(Mutex::_no_safepoint_check_flag); 857 } 858 } 859 860 // call one more level start routine 861 thread->run(); 862 863 return 0; 864 } 865 866 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) { 867 assert(thread->osthread() == NULL, "caller responsible"); 868 869 // Allocate the OSThread object 870 OSThread* osthread = new OSThread(NULL, NULL); 871 if (osthread == NULL) { 872 return false; 873 } 874 875 // set the correct thread state 876 osthread->set_thread_type(thr_type); 877 878 // Initial state is ALLOCATED but not INITIALIZED 879 osthread->set_state(ALLOCATED); 880 881 thread->set_osthread(osthread); 882 883 // init thread attributes 884 pthread_attr_t attr; 885 pthread_attr_init(&attr); 886 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 887 888 // stack size 889 if (os::Linux::supports_variable_stack_size()) { 890 // calculate stack size if it's not specified by caller 891 if (stack_size == 0) { 892 stack_size = os::Linux::default_stack_size(thr_type); 893 894 switch (thr_type) { 895 case os::java_thread: 896 // Java threads use ThreadStackSize which default value can be 897 // changed with the flag -Xss 898 assert (JavaThread::stack_size_at_create() > 0, "this should be set"); 899 stack_size = JavaThread::stack_size_at_create(); 900 break; 901 case os::compiler_thread: 902 if (CompilerThreadStackSize > 0) { 903 stack_size = (size_t)(CompilerThreadStackSize * K); 904 break; 905 } // else fall through: 906 // use VMThreadStackSize if CompilerThreadStackSize is not defined 907 case os::vm_thread: 908 case os::pgc_thread: 909 case os::cgc_thread: 910 case os::watcher_thread: 911 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 912 break; 913 } 914 } 915 916 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 917 pthread_attr_setstacksize(&attr, stack_size); 918 } else { 919 // let pthread_create() pick the default value. 920 } 921 922 // glibc guard page 923 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 924 925 ThreadState state; 926 927 { 928 // Serialize thread creation if we are running with fixed stack LinuxThreads 929 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack(); 930 if (lock) { 931 os::Linux::createThread_lock()->lock_without_safepoint_check(); 932 } 933 934 pthread_t tid; 935 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 936 937 pthread_attr_destroy(&attr); 938 939 if (ret != 0) { 940 if (PrintMiscellaneous && (Verbose || WizardMode)) { 941 perror("pthread_create()"); 942 } 943 // Need to clean up stuff we've allocated so far 944 thread->set_osthread(NULL); 945 delete osthread; 946 if (lock) os::Linux::createThread_lock()->unlock(); 947 return false; 948 } 949 950 // Store pthread info into the OSThread 951 osthread->set_pthread_id(tid); 952 953 // Wait until child thread is either initialized or aborted 954 { 955 Monitor* sync_with_child = osthread->startThread_lock(); 956 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 957 while ((state = osthread->get_state()) == ALLOCATED) { 958 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 959 } 960 } 961 962 if (lock) { 963 os::Linux::createThread_lock()->unlock(); 964 } 965 } 966 967 // Aborted due to thread limit being reached 968 if (state == ZOMBIE) { 969 thread->set_osthread(NULL); 970 delete osthread; 971 return false; 972 } 973 974 // The thread is returned suspended (in state INITIALIZED), 975 // and is started higher up in the call chain 976 assert(state == INITIALIZED, "race condition"); 977 return true; 978 } 979 980 ///////////////////////////////////////////////////////////////////////////// 981 // attach existing thread 982 983 // bootstrap the main thread 984 bool os::create_main_thread(JavaThread* thread) { 985 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 986 return create_attached_thread(thread); 987 } 988 989 bool os::create_attached_thread(JavaThread* thread) { 990 #ifdef ASSERT 991 thread->verify_not_published(); 992 #endif 993 994 // Allocate the OSThread object 995 OSThread* osthread = new OSThread(NULL, NULL); 996 997 if (osthread == NULL) { 998 return false; 999 } 1000 1001 // Store pthread info into the OSThread 1002 osthread->set_thread_id(os::Linux::gettid()); 1003 osthread->set_pthread_id(::pthread_self()); 1004 1005 // initialize floating point control register 1006 os::Linux::init_thread_fpu_state(); 1007 1008 // Initial thread state is RUNNABLE 1009 osthread->set_state(RUNNABLE); 1010 1011 thread->set_osthread(osthread); 1012 1013 if (UseNUMA) { 1014 int lgrp_id = os::numa_get_group_id(); 1015 if (lgrp_id != -1) { 1016 thread->set_lgrp_id(lgrp_id); 1017 } 1018 } 1019 1020 if (os::Linux::is_initial_thread()) { 1021 // If current thread is initial thread, its stack is mapped on demand, 1022 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 1023 // the entire stack region to avoid SEGV in stack banging. 1024 // It is also useful to get around the heap-stack-gap problem on SuSE 1025 // kernel (see 4821821 for details). We first expand stack to the top 1026 // of yellow zone, then enable stack yellow zone (order is significant, 1027 // enabling yellow zone first will crash JVM on SuSE Linux), so there 1028 // is no gap between the last two virtual memory regions. 1029 1030 JavaThread *jt = (JavaThread *)thread; 1031 address addr = jt->stack_yellow_zone_base(); 1032 assert(addr != NULL, "initialization problem?"); 1033 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 1034 1035 osthread->set_expanding_stack(); 1036 os::Linux::manually_expand_stack(jt, addr); 1037 osthread->clear_expanding_stack(); 1038 } 1039 1040 // initialize signal mask for this thread 1041 // and save the caller's signal mask 1042 os::Linux::hotspot_sigmask(thread); 1043 1044 return true; 1045 } 1046 1047 void os::pd_start_thread(Thread* thread) { 1048 OSThread * osthread = thread->osthread(); 1049 assert(osthread->get_state() != INITIALIZED, "just checking"); 1050 Monitor* sync_with_child = osthread->startThread_lock(); 1051 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 1052 sync_with_child->notify(); 1053 } 1054 1055 // Free Linux resources related to the OSThread 1056 void os::free_thread(OSThread* osthread) { 1057 assert(osthread != NULL, "osthread not set"); 1058 1059 if (Thread::current()->osthread() == osthread) { 1060 // Restore caller's signal mask 1061 sigset_t sigmask = osthread->caller_sigmask(); 1062 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1063 } 1064 1065 delete osthread; 1066 } 1067 1068 ////////////////////////////////////////////////////////////////////////////// 1069 // thread local storage 1070 1071 int os::allocate_thread_local_storage() { 1072 pthread_key_t key; 1073 int rslt = pthread_key_create(&key, NULL); 1074 assert(rslt == 0, "cannot allocate thread local storage"); 1075 return (int)key; 1076 } 1077 1078 // Note: This is currently not used by VM, as we don't destroy TLS key 1079 // on VM exit. 1080 void os::free_thread_local_storage(int index) { 1081 int rslt = pthread_key_delete((pthread_key_t)index); 1082 assert(rslt == 0, "invalid index"); 1083 } 1084 1085 void os::thread_local_storage_at_put(int index, void* value) { 1086 int rslt = pthread_setspecific((pthread_key_t)index, value); 1087 assert(rslt == 0, "pthread_setspecific failed"); 1088 } 1089 1090 extern "C" Thread* get_thread() { 1091 return ThreadLocalStorage::thread(); 1092 } 1093 1094 ////////////////////////////////////////////////////////////////////////////// 1095 // initial thread 1096 1097 // Check if current thread is the initial thread, similar to Solaris thr_main. 1098 bool os::Linux::is_initial_thread(void) { 1099 char dummy; 1100 // If called before init complete, thread stack bottom will be null. 1101 // Can be called if fatal error occurs before initialization. 1102 if (initial_thread_stack_bottom() == NULL) return false; 1103 assert(initial_thread_stack_bottom() != NULL && 1104 initial_thread_stack_size() != 0, 1105 "os::init did not locate initial thread's stack region"); 1106 if ((address)&dummy >= initial_thread_stack_bottom() && 1107 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) 1108 return true; 1109 else return false; 1110 } 1111 1112 // Find the virtual memory area that contains addr 1113 static bool find_vma(address addr, address* vma_low, address* vma_high) { 1114 FILE *fp = fopen("/proc/self/maps", "r"); 1115 if (fp) { 1116 address low, high; 1117 while (!feof(fp)) { 1118 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1119 if (low <= addr && addr < high) { 1120 if (vma_low) *vma_low = low; 1121 if (vma_high) *vma_high = high; 1122 fclose (fp); 1123 return true; 1124 } 1125 } 1126 for (;;) { 1127 int ch = fgetc(fp); 1128 if (ch == EOF || ch == (int)'\n') break; 1129 } 1130 } 1131 fclose(fp); 1132 } 1133 return false; 1134 } 1135 1136 // Locate initial thread stack. This special handling of initial thread stack 1137 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 1138 // bogus value for initial thread. 1139 void os::Linux::capture_initial_stack(size_t max_size) { 1140 // stack size is the easy part, get it from RLIMIT_STACK 1141 size_t stack_size; 1142 struct rlimit rlim; 1143 getrlimit(RLIMIT_STACK, &rlim); 1144 stack_size = rlim.rlim_cur; 1145 1146 // 6308388: a bug in ld.so will relocate its own .data section to the 1147 // lower end of primordial stack; reduce ulimit -s value a little bit 1148 // so we won't install guard page on ld.so's data section. 1149 stack_size -= 2 * page_size(); 1150 1151 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 1152 // 7.1, in both cases we will get 2G in return value. 1153 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 1154 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 1155 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 1156 // in case other parts in glibc still assumes 2M max stack size. 1157 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 1158 #ifndef IA64 1159 if (stack_size > 2 * K * K) stack_size = 2 * K * K; 1160 #else 1161 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 1162 if (stack_size > 4 * K * K) stack_size = 4 * K * K; 1163 #endif 1164 1165 // Try to figure out where the stack base (top) is. This is harder. 1166 // 1167 // When an application is started, glibc saves the initial stack pointer in 1168 // a global variable "__libc_stack_end", which is then used by system 1169 // libraries. __libc_stack_end should be pretty close to stack top. The 1170 // variable is available since the very early days. However, because it is 1171 // a private interface, it could disappear in the future. 1172 // 1173 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1174 // to __libc_stack_end, it is very close to stack top, but isn't the real 1175 // stack top. Note that /proc may not exist if VM is running as a chroot 1176 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1177 // /proc/<pid>/stat could change in the future (though unlikely). 1178 // 1179 // We try __libc_stack_end first. If that doesn't work, look for 1180 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1181 // as a hint, which should work well in most cases. 1182 1183 uintptr_t stack_start; 1184 1185 // try __libc_stack_end first 1186 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1187 if (p && *p) { 1188 stack_start = *p; 1189 } else { 1190 // see if we can get the start_stack field from /proc/self/stat 1191 FILE *fp; 1192 int pid; 1193 char state; 1194 int ppid; 1195 int pgrp; 1196 int session; 1197 int nr; 1198 int tpgrp; 1199 unsigned long flags; 1200 unsigned long minflt; 1201 unsigned long cminflt; 1202 unsigned long majflt; 1203 unsigned long cmajflt; 1204 unsigned long utime; 1205 unsigned long stime; 1206 long cutime; 1207 long cstime; 1208 long prio; 1209 long nice; 1210 long junk; 1211 long it_real; 1212 uintptr_t start; 1213 uintptr_t vsize; 1214 intptr_t rss; 1215 uintptr_t rsslim; 1216 uintptr_t scodes; 1217 uintptr_t ecode; 1218 int i; 1219 1220 // Figure what the primordial thread stack base is. Code is inspired 1221 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1222 // followed by command name surrounded by parentheses, state, etc. 1223 char stat[2048]; 1224 int statlen; 1225 1226 fp = fopen("/proc/self/stat", "r"); 1227 if (fp) { 1228 statlen = fread(stat, 1, 2047, fp); 1229 stat[statlen] = '\0'; 1230 fclose(fp); 1231 1232 // Skip pid and the command string. Note that we could be dealing with 1233 // weird command names, e.g. user could decide to rename java launcher 1234 // to "java 1.4.2 :)", then the stat file would look like 1235 // 1234 (java 1.4.2 :)) R ... ... 1236 // We don't really need to know the command string, just find the last 1237 // occurrence of ")" and then start parsing from there. See bug 4726580. 1238 char * s = strrchr(stat, ')'); 1239 1240 i = 0; 1241 if (s) { 1242 // Skip blank chars 1243 do s++; while (isspace(*s)); 1244 1245 #define _UFM UINTX_FORMAT 1246 #define _DFM INTX_FORMAT 1247 1248 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */ 1249 /* 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 */ 1250 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM, 1251 &state, /* 3 %c */ 1252 &ppid, /* 4 %d */ 1253 &pgrp, /* 5 %d */ 1254 &session, /* 6 %d */ 1255 &nr, /* 7 %d */ 1256 &tpgrp, /* 8 %d */ 1257 &flags, /* 9 %lu */ 1258 &minflt, /* 10 %lu */ 1259 &cminflt, /* 11 %lu */ 1260 &majflt, /* 12 %lu */ 1261 &cmajflt, /* 13 %lu */ 1262 &utime, /* 14 %lu */ 1263 &stime, /* 15 %lu */ 1264 &cutime, /* 16 %ld */ 1265 &cstime, /* 17 %ld */ 1266 &prio, /* 18 %ld */ 1267 &nice, /* 19 %ld */ 1268 &junk, /* 20 %ld */ 1269 &it_real, /* 21 %ld */ 1270 &start, /* 22 UINTX_FORMAT */ 1271 &vsize, /* 23 UINTX_FORMAT */ 1272 &rss, /* 24 INTX_FORMAT */ 1273 &rsslim, /* 25 UINTX_FORMAT */ 1274 &scodes, /* 26 UINTX_FORMAT */ 1275 &ecode, /* 27 UINTX_FORMAT */ 1276 &stack_start); /* 28 UINTX_FORMAT */ 1277 } 1278 1279 #undef _UFM 1280 #undef _DFM 1281 1282 if (i != 28 - 2) { 1283 assert(false, "Bad conversion from /proc/self/stat"); 1284 // product mode - assume we are the initial thread, good luck in the 1285 // embedded case. 1286 warning("Can't detect initial thread stack location - bad conversion"); 1287 stack_start = (uintptr_t) &rlim; 1288 } 1289 } else { 1290 // For some reason we can't open /proc/self/stat (for example, running on 1291 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1292 // most cases, so don't abort: 1293 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1294 stack_start = (uintptr_t) &rlim; 1295 } 1296 } 1297 1298 // Now we have a pointer (stack_start) very close to the stack top, the 1299 // next thing to do is to figure out the exact location of stack top. We 1300 // can find out the virtual memory area that contains stack_start by 1301 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1302 // and its upper limit is the real stack top. (again, this would fail if 1303 // running inside chroot, because /proc may not exist.) 1304 1305 uintptr_t stack_top; 1306 address low, high; 1307 if (find_vma((address)stack_start, &low, &high)) { 1308 // success, "high" is the true stack top. (ignore "low", because initial 1309 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1310 stack_top = (uintptr_t)high; 1311 } else { 1312 // failed, likely because /proc/self/maps does not exist 1313 warning("Can't detect initial thread stack location - find_vma failed"); 1314 // best effort: stack_start is normally within a few pages below the real 1315 // stack top, use it as stack top, and reduce stack size so we won't put 1316 // guard page outside stack. 1317 stack_top = stack_start; 1318 stack_size -= 16 * page_size(); 1319 } 1320 1321 // stack_top could be partially down the page so align it 1322 stack_top = align_size_up(stack_top, page_size()); 1323 1324 if (max_size && stack_size > max_size) { 1325 _initial_thread_stack_size = max_size; 1326 } else { 1327 _initial_thread_stack_size = stack_size; 1328 } 1329 1330 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1331 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1332 } 1333 1334 //////////////////////////////////////////////////////////////////////////////// 1335 // time support 1336 1337 // Time since start-up in seconds to a fine granularity. 1338 // Used by VMSelfDestructTimer and the MemProfiler. 1339 double os::elapsedTime() { 1340 1341 return (double)(os::elapsed_counter()) * 0.000001; 1342 } 1343 1344 jlong os::elapsed_counter() { 1345 timeval time; 1346 int status = gettimeofday(&time, NULL); 1347 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count; 1348 } 1349 1350 jlong os::elapsed_frequency() { 1351 return (1000 * 1000); 1352 } 1353 1354 // For now, we say that linux does not support vtime. I have no idea 1355 // whether it can actually be made to (DLD, 9/13/05). 1356 1357 bool os::supports_vtime() { return false; } 1358 bool os::enable_vtime() { return false; } 1359 bool os::vtime_enabled() { return false; } 1360 double os::elapsedVTime() { 1361 // better than nothing, but not much 1362 return elapsedTime(); 1363 } 1364 1365 jlong os::javaTimeMillis() { 1366 timeval time; 1367 int status = gettimeofday(&time, NULL); 1368 assert(status != -1, "linux error"); 1369 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1370 } 1371 1372 #ifndef CLOCK_MONOTONIC 1373 #define CLOCK_MONOTONIC (1) 1374 #endif 1375 1376 void os::Linux::clock_init() { 1377 // we do dlopen's in this particular order due to bug in linux 1378 // dynamical loader (see 6348968) leading to crash on exit 1379 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1380 if (handle == NULL) { 1381 handle = dlopen("librt.so", RTLD_LAZY); 1382 } 1383 1384 if (handle) { 1385 int (*clock_getres_func)(clockid_t, struct timespec*) = 1386 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1387 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1388 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1389 if (clock_getres_func && clock_gettime_func) { 1390 // See if monotonic clock is supported by the kernel. Note that some 1391 // early implementations simply return kernel jiffies (updated every 1392 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1393 // for nano time (though the monotonic property is still nice to have). 1394 // It's fixed in newer kernels, however clock_getres() still returns 1395 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1396 // resolution for now. Hopefully as people move to new kernels, this 1397 // won't be a problem. 1398 struct timespec res; 1399 struct timespec tp; 1400 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1401 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1402 // yes, monotonic clock is supported 1403 _clock_gettime = clock_gettime_func; 1404 } else { 1405 // close librt if there is no monotonic clock 1406 dlclose(handle); 1407 } 1408 } 1409 } 1410 } 1411 1412 #ifndef SYS_clock_getres 1413 1414 #if defined(IA32) || defined(AMD64) 1415 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1416 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1417 #else 1418 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1419 #define sys_clock_getres(x,y) -1 1420 #endif 1421 1422 #else 1423 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1424 #endif 1425 1426 void os::Linux::fast_thread_clock_init() { 1427 if (!UseLinuxPosixThreadCPUClocks) { 1428 return; 1429 } 1430 clockid_t clockid; 1431 struct timespec tp; 1432 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1433 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1434 1435 // Switch to using fast clocks for thread cpu time if 1436 // the sys_clock_getres() returns 0 error code. 1437 // Note, that some kernels may support the current thread 1438 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1439 // returned by the pthread_getcpuclockid(). 1440 // If the fast Posix clocks are supported then the sys_clock_getres() 1441 // must return at least tp.tv_sec == 0 which means a resolution 1442 // better than 1 sec. This is extra check for reliability. 1443 1444 if(pthread_getcpuclockid_func && 1445 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1446 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1447 1448 _supports_fast_thread_cpu_time = true; 1449 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1450 } 1451 } 1452 1453 jlong os::javaTimeNanos() { 1454 if (Linux::supports_monotonic_clock()) { 1455 struct timespec tp; 1456 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1457 assert(status == 0, "gettime error"); 1458 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1459 return result; 1460 } else { 1461 timeval time; 1462 int status = gettimeofday(&time, NULL); 1463 assert(status != -1, "linux error"); 1464 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1465 return 1000 * usecs; 1466 } 1467 } 1468 1469 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1470 if (Linux::supports_monotonic_clock()) { 1471 info_ptr->max_value = ALL_64_BITS; 1472 1473 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1474 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1475 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1476 } else { 1477 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1478 info_ptr->max_value = ALL_64_BITS; 1479 1480 // gettimeofday is a real time clock so it skips 1481 info_ptr->may_skip_backward = true; 1482 info_ptr->may_skip_forward = true; 1483 } 1484 1485 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1486 } 1487 1488 // Return the real, user, and system times in seconds from an 1489 // arbitrary fixed point in the past. 1490 bool os::getTimesSecs(double* process_real_time, 1491 double* process_user_time, 1492 double* process_system_time) { 1493 struct tms ticks; 1494 clock_t real_ticks = times(&ticks); 1495 1496 if (real_ticks == (clock_t) (-1)) { 1497 return false; 1498 } else { 1499 double ticks_per_second = (double) clock_tics_per_sec; 1500 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1501 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1502 *process_real_time = ((double) real_ticks) / ticks_per_second; 1503 1504 return true; 1505 } 1506 } 1507 1508 1509 char * os::local_time_string(char *buf, size_t buflen) { 1510 struct tm t; 1511 time_t long_time; 1512 time(&long_time); 1513 localtime_r(&long_time, &t); 1514 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1515 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1516 t.tm_hour, t.tm_min, t.tm_sec); 1517 return buf; 1518 } 1519 1520 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1521 return localtime_r(clock, res); 1522 } 1523 1524 //////////////////////////////////////////////////////////////////////////////// 1525 // runtime exit support 1526 1527 // Note: os::shutdown() might be called very early during initialization, or 1528 // called from signal handler. Before adding something to os::shutdown(), make 1529 // sure it is async-safe and can handle partially initialized VM. 1530 void os::shutdown() { 1531 1532 // allow PerfMemory to attempt cleanup of any persistent resources 1533 perfMemory_exit(); 1534 1535 // needs to remove object in file system 1536 AttachListener::abort(); 1537 1538 // flush buffered output, finish log files 1539 ostream_abort(); 1540 1541 // Check for abort hook 1542 abort_hook_t abort_hook = Arguments::abort_hook(); 1543 if (abort_hook != NULL) { 1544 abort_hook(); 1545 } 1546 1547 } 1548 1549 // Note: os::abort() might be called very early during initialization, or 1550 // called from signal handler. Before adding something to os::abort(), make 1551 // sure it is async-safe and can handle partially initialized VM. 1552 void os::abort(bool dump_core) { 1553 os::shutdown(); 1554 if (dump_core) { 1555 #ifndef PRODUCT 1556 fdStream out(defaultStream::output_fd()); 1557 out.print_raw("Current thread is "); 1558 char buf[16]; 1559 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1560 out.print_raw_cr(buf); 1561 out.print_raw_cr("Dumping core ..."); 1562 #endif 1563 ::abort(); // dump core 1564 } 1565 1566 ::exit(1); 1567 } 1568 1569 // Die immediately, no exit hook, no abort hook, no cleanup. 1570 void os::die() { 1571 // _exit() on LinuxThreads only kills current thread 1572 ::abort(); 1573 } 1574 1575 // unused on linux for now. 1576 void os::set_error_file(const char *logfile) {} 1577 1578 1579 // This method is a copy of JDK's sysGetLastErrorString 1580 // from src/solaris/hpi/src/system_md.c 1581 1582 size_t os::lasterror(char *buf, size_t len) { 1583 1584 if (errno == 0) return 0; 1585 1586 const char *s = ::strerror(errno); 1587 size_t n = ::strlen(s); 1588 if (n >= len) { 1589 n = len - 1; 1590 } 1591 ::strncpy(buf, s, n); 1592 buf[n] = '\0'; 1593 return n; 1594 } 1595 1596 intx os::current_thread_id() { return (intx)pthread_self(); } 1597 int os::current_process_id() { 1598 1599 // Under the old linux thread library, linux gives each thread 1600 // its own process id. Because of this each thread will return 1601 // a different pid if this method were to return the result 1602 // of getpid(2). Linux provides no api that returns the pid 1603 // of the launcher thread for the vm. This implementation 1604 // returns a unique pid, the pid of the launcher thread 1605 // that starts the vm 'process'. 1606 1607 // Under the NPTL, getpid() returns the same pid as the 1608 // launcher thread rather than a unique pid per thread. 1609 // Use gettid() if you want the old pre NPTL behaviour. 1610 1611 // if you are looking for the result of a call to getpid() that 1612 // returns a unique pid for the calling thread, then look at the 1613 // OSThread::thread_id() method in osThread_linux.hpp file 1614 1615 return (int)(_initial_pid ? _initial_pid : getpid()); 1616 } 1617 1618 // DLL functions 1619 1620 const char* os::dll_file_extension() { return ".so"; } 1621 1622 // This must be hard coded because it's the system's temporary 1623 // directory not the java application's temp directory, ala java.io.tmpdir. 1624 const char* os::get_temp_directory() { return "/tmp"; } 1625 1626 static bool file_exists(const char* filename) { 1627 struct stat statbuf; 1628 if (filename == NULL || strlen(filename) == 0) { 1629 return false; 1630 } 1631 return os::stat(filename, &statbuf) == 0; 1632 } 1633 1634 void os::dll_build_name(char* buffer, size_t buflen, 1635 const char* pname, const char* fname) { 1636 // Copied from libhpi 1637 const size_t pnamelen = pname ? strlen(pname) : 0; 1638 1639 // Quietly truncate on buffer overflow. Should be an error. 1640 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1641 *buffer = '\0'; 1642 return; 1643 } 1644 1645 if (pnamelen == 0) { 1646 snprintf(buffer, buflen, "lib%s.so", fname); 1647 } else if (strchr(pname, *os::path_separator()) != NULL) { 1648 int n; 1649 char** pelements = split_path(pname, &n); 1650 for (int i = 0 ; i < n ; i++) { 1651 // Really shouldn't be NULL, but check can't hurt 1652 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1653 continue; // skip the empty path values 1654 } 1655 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1656 if (file_exists(buffer)) { 1657 break; 1658 } 1659 } 1660 // release the storage 1661 for (int i = 0 ; i < n ; i++) { 1662 if (pelements[i] != NULL) { 1663 FREE_C_HEAP_ARRAY(char, pelements[i]); 1664 } 1665 } 1666 if (pelements != NULL) { 1667 FREE_C_HEAP_ARRAY(char*, pelements); 1668 } 1669 } else { 1670 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1671 } 1672 } 1673 1674 const char* os::get_current_directory(char *buf, int buflen) { 1675 return getcwd(buf, buflen); 1676 } 1677 1678 // check if addr is inside libjvm[_g].so 1679 bool os::address_is_in_vm(address addr) { 1680 static address libjvm_base_addr; 1681 Dl_info dlinfo; 1682 1683 if (libjvm_base_addr == NULL) { 1684 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo); 1685 libjvm_base_addr = (address)dlinfo.dli_fbase; 1686 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1687 } 1688 1689 if (dladdr((void *)addr, &dlinfo)) { 1690 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1691 } 1692 1693 return false; 1694 } 1695 1696 bool os::dll_address_to_function_name(address addr, char *buf, 1697 int buflen, int *offset) { 1698 Dl_info dlinfo; 1699 1700 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) { 1701 if (buf != NULL) { 1702 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) { 1703 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1704 } 1705 } 1706 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1707 return true; 1708 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) { 1709 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1710 dlinfo.dli_fname, buf, buflen, offset) == Decoder::no_error) { 1711 return true; 1712 } 1713 } 1714 1715 if (buf != NULL) buf[0] = '\0'; 1716 if (offset != NULL) *offset = -1; 1717 return false; 1718 } 1719 1720 struct _address_to_library_name { 1721 address addr; // input : memory address 1722 size_t buflen; // size of fname 1723 char* fname; // output: library name 1724 address base; // library base addr 1725 }; 1726 1727 static int address_to_library_name_callback(struct dl_phdr_info *info, 1728 size_t size, void *data) { 1729 int i; 1730 bool found = false; 1731 address libbase = NULL; 1732 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1733 1734 // iterate through all loadable segments 1735 for (i = 0; i < info->dlpi_phnum; i++) { 1736 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1737 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1738 // base address of a library is the lowest address of its loaded 1739 // segments. 1740 if (libbase == NULL || libbase > segbase) { 1741 libbase = segbase; 1742 } 1743 // see if 'addr' is within current segment 1744 if (segbase <= d->addr && 1745 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1746 found = true; 1747 } 1748 } 1749 } 1750 1751 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1752 // so dll_address_to_library_name() can fall through to use dladdr() which 1753 // can figure out executable name from argv[0]. 1754 if (found && info->dlpi_name && info->dlpi_name[0]) { 1755 d->base = libbase; 1756 if (d->fname) { 1757 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1758 } 1759 return 1; 1760 } 1761 return 0; 1762 } 1763 1764 bool os::dll_address_to_library_name(address addr, char* buf, 1765 int buflen, int* offset) { 1766 Dl_info dlinfo; 1767 struct _address_to_library_name data; 1768 1769 // There is a bug in old glibc dladdr() implementation that it could resolve 1770 // to wrong library name if the .so file has a base address != NULL. Here 1771 // we iterate through the program headers of all loaded libraries to find 1772 // out which library 'addr' really belongs to. This workaround can be 1773 // removed once the minimum requirement for glibc is moved to 2.3.x. 1774 data.addr = addr; 1775 data.fname = buf; 1776 data.buflen = buflen; 1777 data.base = NULL; 1778 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1779 1780 if (rslt) { 1781 // buf already contains library name 1782 if (offset) *offset = addr - data.base; 1783 return true; 1784 } else if (dladdr((void*)addr, &dlinfo)){ 1785 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1786 if (offset) *offset = addr - (address)dlinfo.dli_fbase; 1787 return true; 1788 } else { 1789 if (buf) buf[0] = '\0'; 1790 if (offset) *offset = -1; 1791 return false; 1792 } 1793 } 1794 1795 // Loads .dll/.so and 1796 // in case of error it checks if .dll/.so was built for the 1797 // same architecture as Hotspot is running on 1798 1799 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) 1800 { 1801 void * result= ::dlopen(filename, RTLD_LAZY); 1802 if (result != NULL) { 1803 // Successful loading 1804 return result; 1805 } 1806 1807 Elf32_Ehdr elf_head; 1808 1809 // Read system error message into ebuf 1810 // It may or may not be overwritten below 1811 ::strncpy(ebuf, ::dlerror(), ebuflen-1); 1812 ebuf[ebuflen-1]='\0'; 1813 int diag_msg_max_length=ebuflen-strlen(ebuf); 1814 char* diag_msg_buf=ebuf+strlen(ebuf); 1815 1816 if (diag_msg_max_length==0) { 1817 // No more space in ebuf for additional diagnostics message 1818 return NULL; 1819 } 1820 1821 1822 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1823 1824 if (file_descriptor < 0) { 1825 // Can't open library, report dlerror() message 1826 return NULL; 1827 } 1828 1829 bool failed_to_read_elf_head= 1830 (sizeof(elf_head)!= 1831 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ; 1832 1833 ::close(file_descriptor); 1834 if (failed_to_read_elf_head) { 1835 // file i/o error - report dlerror() msg 1836 return NULL; 1837 } 1838 1839 typedef struct { 1840 Elf32_Half code; // Actual value as defined in elf.h 1841 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1842 char elf_class; // 32 or 64 bit 1843 char endianess; // MSB or LSB 1844 char* name; // String representation 1845 } arch_t; 1846 1847 #ifndef EM_486 1848 #define EM_486 6 /* Intel 80486 */ 1849 #endif 1850 1851 static const arch_t arch_array[]={ 1852 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1853 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1854 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1855 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1856 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1857 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1858 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1859 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1860 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1861 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1862 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1863 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1864 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1865 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1866 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1867 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"} 1868 }; 1869 1870 #if (defined IA32) 1871 static Elf32_Half running_arch_code=EM_386; 1872 #elif (defined AMD64) 1873 static Elf32_Half running_arch_code=EM_X86_64; 1874 #elif (defined IA64) 1875 static Elf32_Half running_arch_code=EM_IA_64; 1876 #elif (defined __sparc) && (defined _LP64) 1877 static Elf32_Half running_arch_code=EM_SPARCV9; 1878 #elif (defined __sparc) && (!defined _LP64) 1879 static Elf32_Half running_arch_code=EM_SPARC; 1880 #elif (defined __powerpc64__) 1881 static Elf32_Half running_arch_code=EM_PPC64; 1882 #elif (defined __powerpc__) 1883 static Elf32_Half running_arch_code=EM_PPC; 1884 #elif (defined ARM) 1885 static Elf32_Half running_arch_code=EM_ARM; 1886 #elif (defined S390) 1887 static Elf32_Half running_arch_code=EM_S390; 1888 #elif (defined ALPHA) 1889 static Elf32_Half running_arch_code=EM_ALPHA; 1890 #elif (defined MIPSEL) 1891 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1892 #elif (defined PARISC) 1893 static Elf32_Half running_arch_code=EM_PARISC; 1894 #elif (defined MIPS) 1895 static Elf32_Half running_arch_code=EM_MIPS; 1896 #elif (defined M68K) 1897 static Elf32_Half running_arch_code=EM_68K; 1898 #else 1899 #error Method os::dll_load requires that one of following is defined:\ 1900 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K 1901 #endif 1902 1903 // Identify compatability class for VM's architecture and library's architecture 1904 // Obtain string descriptions for architectures 1905 1906 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1907 int running_arch_index=-1; 1908 1909 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) { 1910 if (running_arch_code == arch_array[i].code) { 1911 running_arch_index = i; 1912 } 1913 if (lib_arch.code == arch_array[i].code) { 1914 lib_arch.compat_class = arch_array[i].compat_class; 1915 lib_arch.name = arch_array[i].name; 1916 } 1917 } 1918 1919 assert(running_arch_index != -1, 1920 "Didn't find running architecture code (running_arch_code) in arch_array"); 1921 if (running_arch_index == -1) { 1922 // Even though running architecture detection failed 1923 // we may still continue with reporting dlerror() message 1924 return NULL; 1925 } 1926 1927 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1928 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1929 return NULL; 1930 } 1931 1932 #ifndef S390 1933 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1934 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1935 return NULL; 1936 } 1937 #endif // !S390 1938 1939 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1940 if ( lib_arch.name!=NULL ) { 1941 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1942 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1943 lib_arch.name, arch_array[running_arch_index].name); 1944 } else { 1945 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1946 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1947 lib_arch.code, 1948 arch_array[running_arch_index].name); 1949 } 1950 } 1951 1952 return NULL; 1953 } 1954 1955 /* 1956 * glibc-2.0 libdl is not MT safe. If you are building with any glibc, 1957 * chances are you might want to run the generated bits against glibc-2.0 1958 * libdl.so, so always use locking for any version of glibc. 1959 */ 1960 void* os::dll_lookup(void* handle, const char* name) { 1961 pthread_mutex_lock(&dl_mutex); 1962 void* res = dlsym(handle, name); 1963 pthread_mutex_unlock(&dl_mutex); 1964 return res; 1965 } 1966 1967 1968 static bool _print_ascii_file(const char* filename, outputStream* st) { 1969 int fd = ::open(filename, O_RDONLY); 1970 if (fd == -1) { 1971 return false; 1972 } 1973 1974 char buf[32]; 1975 int bytes; 1976 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 1977 st->print_raw(buf, bytes); 1978 } 1979 1980 ::close(fd); 1981 1982 return true; 1983 } 1984 1985 void os::print_dll_info(outputStream *st) { 1986 st->print_cr("Dynamic libraries:"); 1987 1988 char fname[32]; 1989 pid_t pid = os::Linux::gettid(); 1990 1991 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1992 1993 if (!_print_ascii_file(fname, st)) { 1994 st->print("Can not get library information for pid = %d\n", pid); 1995 } 1996 } 1997 1998 1999 void os::print_os_info(outputStream* st) { 2000 st->print("OS:"); 2001 2002 // Try to identify popular distros. 2003 // Most Linux distributions have /etc/XXX-release file, which contains 2004 // the OS version string. Some have more than one /etc/XXX-release file 2005 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.), 2006 // so the order is important. 2007 if (!_print_ascii_file("/etc/mandrake-release", st) && 2008 !_print_ascii_file("/etc/sun-release", st) && 2009 !_print_ascii_file("/etc/redhat-release", st) && 2010 !_print_ascii_file("/etc/SuSE-release", st) && 2011 !_print_ascii_file("/etc/turbolinux-release", st) && 2012 !_print_ascii_file("/etc/gentoo-release", st) && 2013 !_print_ascii_file("/etc/debian_version", st) && 2014 !_print_ascii_file("/etc/ltib-release", st) && 2015 !_print_ascii_file("/etc/angstrom-version", st)) { 2016 st->print("Linux"); 2017 } 2018 st->cr(); 2019 2020 // kernel 2021 st->print("uname:"); 2022 struct utsname name; 2023 uname(&name); 2024 st->print(name.sysname); st->print(" "); 2025 st->print(name.release); st->print(" "); 2026 st->print(name.version); st->print(" "); 2027 st->print(name.machine); 2028 st->cr(); 2029 2030 // Print warning if unsafe chroot environment detected 2031 if (unsafe_chroot_detected) { 2032 st->print("WARNING!! "); 2033 st->print_cr(unstable_chroot_error); 2034 } 2035 2036 // libc, pthread 2037 st->print("libc:"); 2038 st->print(os::Linux::glibc_version()); st->print(" "); 2039 st->print(os::Linux::libpthread_version()); st->print(" "); 2040 if (os::Linux::is_LinuxThreads()) { 2041 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed"); 2042 } 2043 st->cr(); 2044 2045 // rlimit 2046 st->print("rlimit:"); 2047 struct rlimit rlim; 2048 2049 st->print(" STACK "); 2050 getrlimit(RLIMIT_STACK, &rlim); 2051 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2052 else st->print("%uk", rlim.rlim_cur >> 10); 2053 2054 st->print(", CORE "); 2055 getrlimit(RLIMIT_CORE, &rlim); 2056 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2057 else st->print("%uk", rlim.rlim_cur >> 10); 2058 2059 st->print(", NPROC "); 2060 getrlimit(RLIMIT_NPROC, &rlim); 2061 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2062 else st->print("%d", rlim.rlim_cur); 2063 2064 st->print(", NOFILE "); 2065 getrlimit(RLIMIT_NOFILE, &rlim); 2066 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2067 else st->print("%d", rlim.rlim_cur); 2068 2069 st->print(", AS "); 2070 getrlimit(RLIMIT_AS, &rlim); 2071 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2072 else st->print("%uk", rlim.rlim_cur >> 10); 2073 st->cr(); 2074 2075 // load average 2076 st->print("load average:"); 2077 double loadavg[3]; 2078 os::loadavg(loadavg, 3); 2079 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]); 2080 st->cr(); 2081 2082 // meminfo 2083 st->print("\n/proc/meminfo:\n"); 2084 _print_ascii_file("/proc/meminfo", st); 2085 st->cr(); 2086 } 2087 2088 void os::print_memory_info(outputStream* st) { 2089 2090 st->print("Memory:"); 2091 st->print(" %dk page", os::vm_page_size()>>10); 2092 2093 // values in struct sysinfo are "unsigned long" 2094 struct sysinfo si; 2095 sysinfo(&si); 2096 2097 st->print(", physical " UINT64_FORMAT "k", 2098 os::physical_memory() >> 10); 2099 st->print("(" UINT64_FORMAT "k free)", 2100 os::available_memory() >> 10); 2101 st->print(", swap " UINT64_FORMAT "k", 2102 ((jlong)si.totalswap * si.mem_unit) >> 10); 2103 st->print("(" UINT64_FORMAT "k free)", 2104 ((jlong)si.freeswap * si.mem_unit) >> 10); 2105 st->cr(); 2106 } 2107 2108 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific 2109 // but they're the same for all the linux arch that we support 2110 // and they're the same for solaris but there's no common place to put this. 2111 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR", 2112 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG", 2113 "ILL_COPROC", "ILL_BADSTK" }; 2114 2115 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV", 2116 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES", 2117 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" }; 2118 2119 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" }; 2120 2121 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" }; 2122 2123 void os::print_siginfo(outputStream* st, void* siginfo) { 2124 st->print("siginfo:"); 2125 2126 const int buflen = 100; 2127 char buf[buflen]; 2128 siginfo_t *si = (siginfo_t*)siginfo; 2129 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen)); 2130 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) { 2131 st->print("si_errno=%s", buf); 2132 } else { 2133 st->print("si_errno=%d", si->si_errno); 2134 } 2135 const int c = si->si_code; 2136 assert(c > 0, "unexpected si_code"); 2137 switch (si->si_signo) { 2138 case SIGILL: 2139 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]); 2140 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2141 break; 2142 case SIGFPE: 2143 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]); 2144 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2145 break; 2146 case SIGSEGV: 2147 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]); 2148 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2149 break; 2150 case SIGBUS: 2151 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]); 2152 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2153 break; 2154 default: 2155 st->print(", si_code=%d", si->si_code); 2156 // no si_addr 2157 } 2158 2159 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2160 UseSharedSpaces) { 2161 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2162 if (mapinfo->is_in_shared_space(si->si_addr)) { 2163 st->print("\n\nError accessing class data sharing archive." \ 2164 " Mapped file inaccessible during execution, " \ 2165 " possible disk/network problem."); 2166 } 2167 } 2168 st->cr(); 2169 } 2170 2171 2172 static void print_signal_handler(outputStream* st, int sig, 2173 char* buf, size_t buflen); 2174 2175 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2176 st->print_cr("Signal Handlers:"); 2177 print_signal_handler(st, SIGSEGV, buf, buflen); 2178 print_signal_handler(st, SIGBUS , buf, buflen); 2179 print_signal_handler(st, SIGFPE , buf, buflen); 2180 print_signal_handler(st, SIGPIPE, buf, buflen); 2181 print_signal_handler(st, SIGXFSZ, buf, buflen); 2182 print_signal_handler(st, SIGILL , buf, buflen); 2183 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2184 print_signal_handler(st, SR_signum, buf, buflen); 2185 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2186 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2187 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2188 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2189 } 2190 2191 static char saved_jvm_path[MAXPATHLEN] = {0}; 2192 2193 // Find the full path to the current module, libjvm.so or libjvm_g.so 2194 void os::jvm_path(char *buf, jint buflen) { 2195 // Error checking. 2196 if (buflen < MAXPATHLEN) { 2197 assert(false, "must use a large-enough buffer"); 2198 buf[0] = '\0'; 2199 return; 2200 } 2201 // Lazy resolve the path to current module. 2202 if (saved_jvm_path[0] != 0) { 2203 strcpy(buf, saved_jvm_path); 2204 return; 2205 } 2206 2207 char dli_fname[MAXPATHLEN]; 2208 bool ret = dll_address_to_library_name( 2209 CAST_FROM_FN_PTR(address, os::jvm_path), 2210 dli_fname, sizeof(dli_fname), NULL); 2211 assert(ret != 0, "cannot locate libjvm"); 2212 char *rp = realpath(dli_fname, buf); 2213 if (rp == NULL) 2214 return; 2215 2216 if (Arguments::created_by_gamma_launcher()) { 2217 // Support for the gamma launcher. Typical value for buf is 2218 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at 2219 // the right place in the string, then assume we are installed in a JDK and 2220 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix 2221 // up the path so it looks like libjvm.so is installed there (append a 2222 // fake suffix hotspot/libjvm.so). 2223 const char *p = buf + strlen(buf) - 1; 2224 for (int count = 0; p > buf && count < 5; ++count) { 2225 for (--p; p > buf && *p != '/'; --p) 2226 /* empty */ ; 2227 } 2228 2229 if (strncmp(p, "/jre/lib/", 9) != 0) { 2230 // Look for JAVA_HOME in the environment. 2231 char* java_home_var = ::getenv("JAVA_HOME"); 2232 if (java_home_var != NULL && java_home_var[0] != 0) { 2233 char* jrelib_p; 2234 int len; 2235 2236 // Check the current module name "libjvm.so" or "libjvm_g.so". 2237 p = strrchr(buf, '/'); 2238 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2239 p = strstr(p, "_g") ? "_g" : ""; 2240 2241 rp = realpath(java_home_var, buf); 2242 if (rp == NULL) 2243 return; 2244 2245 // determine if this is a legacy image or modules image 2246 // modules image doesn't have "jre" subdirectory 2247 len = strlen(buf); 2248 jrelib_p = buf + len; 2249 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2250 if (0 != access(buf, F_OK)) { 2251 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2252 } 2253 2254 if (0 == access(buf, F_OK)) { 2255 // Use current module name "libjvm[_g].so" instead of 2256 // "libjvm"debug_only("_g")".so" since for fastdebug version 2257 // we should have "libjvm.so" but debug_only("_g") adds "_g"! 2258 len = strlen(buf); 2259 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p); 2260 } else { 2261 // Go back to path of .so 2262 rp = realpath(dli_fname, buf); 2263 if (rp == NULL) 2264 return; 2265 } 2266 } 2267 } 2268 } 2269 2270 strcpy(saved_jvm_path, buf); 2271 } 2272 2273 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2274 // no prefix required, not even "_" 2275 } 2276 2277 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2278 // no suffix required 2279 } 2280 2281 //////////////////////////////////////////////////////////////////////////////// 2282 // sun.misc.Signal support 2283 2284 static volatile jint sigint_count = 0; 2285 2286 static void 2287 UserHandler(int sig, void *siginfo, void *context) { 2288 // 4511530 - sem_post is serialized and handled by the manager thread. When 2289 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2290 // don't want to flood the manager thread with sem_post requests. 2291 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) 2292 return; 2293 2294 // Ctrl-C is pressed during error reporting, likely because the error 2295 // handler fails to abort. Let VM die immediately. 2296 if (sig == SIGINT && is_error_reported()) { 2297 os::die(); 2298 } 2299 2300 os::signal_notify(sig); 2301 } 2302 2303 void* os::user_handler() { 2304 return CAST_FROM_FN_PTR(void*, UserHandler); 2305 } 2306 2307 extern "C" { 2308 typedef void (*sa_handler_t)(int); 2309 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2310 } 2311 2312 void* os::signal(int signal_number, void* handler) { 2313 struct sigaction sigAct, oldSigAct; 2314 2315 sigfillset(&(sigAct.sa_mask)); 2316 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2317 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2318 2319 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2320 // -1 means registration failed 2321 return (void *)-1; 2322 } 2323 2324 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2325 } 2326 2327 void os::signal_raise(int signal_number) { 2328 ::raise(signal_number); 2329 } 2330 2331 /* 2332 * The following code is moved from os.cpp for making this 2333 * code platform specific, which it is by its very nature. 2334 */ 2335 2336 // Will be modified when max signal is changed to be dynamic 2337 int os::sigexitnum_pd() { 2338 return NSIG; 2339 } 2340 2341 // a counter for each possible signal value 2342 static volatile jint pending_signals[NSIG+1] = { 0 }; 2343 2344 // Linux(POSIX) specific hand shaking semaphore. 2345 static sem_t sig_sem; 2346 2347 void os::signal_init_pd() { 2348 // Initialize signal structures 2349 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2350 2351 // Initialize signal semaphore 2352 ::sem_init(&sig_sem, 0, 0); 2353 } 2354 2355 void os::signal_notify(int sig) { 2356 Atomic::inc(&pending_signals[sig]); 2357 ::sem_post(&sig_sem); 2358 } 2359 2360 static int check_pending_signals(bool wait) { 2361 Atomic::store(0, &sigint_count); 2362 for (;;) { 2363 for (int i = 0; i < NSIG + 1; i++) { 2364 jint n = pending_signals[i]; 2365 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2366 return i; 2367 } 2368 } 2369 if (!wait) { 2370 return -1; 2371 } 2372 JavaThread *thread = JavaThread::current(); 2373 ThreadBlockInVM tbivm(thread); 2374 2375 bool threadIsSuspended; 2376 do { 2377 thread->set_suspend_equivalent(); 2378 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2379 ::sem_wait(&sig_sem); 2380 2381 // were we externally suspended while we were waiting? 2382 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2383 if (threadIsSuspended) { 2384 // 2385 // The semaphore has been incremented, but while we were waiting 2386 // another thread suspended us. We don't want to continue running 2387 // while suspended because that would surprise the thread that 2388 // suspended us. 2389 // 2390 ::sem_post(&sig_sem); 2391 2392 thread->java_suspend_self(); 2393 } 2394 } while (threadIsSuspended); 2395 } 2396 } 2397 2398 int os::signal_lookup() { 2399 return check_pending_signals(false); 2400 } 2401 2402 int os::signal_wait() { 2403 return check_pending_signals(true); 2404 } 2405 2406 //////////////////////////////////////////////////////////////////////////////// 2407 // Virtual Memory 2408 2409 int os::vm_page_size() { 2410 // Seems redundant as all get out 2411 assert(os::Linux::page_size() != -1, "must call os::init"); 2412 return os::Linux::page_size(); 2413 } 2414 2415 // Solaris allocates memory by pages. 2416 int os::vm_allocation_granularity() { 2417 assert(os::Linux::page_size() != -1, "must call os::init"); 2418 return os::Linux::page_size(); 2419 } 2420 2421 // Rationale behind this function: 2422 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2423 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2424 // samples for JITted code. Here we create private executable mapping over the code cache 2425 // and then we can use standard (well, almost, as mapping can change) way to provide 2426 // info for the reporting script by storing timestamp and location of symbol 2427 void linux_wrap_code(char* base, size_t size) { 2428 static volatile jint cnt = 0; 2429 2430 if (!UseOprofile) { 2431 return; 2432 } 2433 2434 char buf[PATH_MAX+1]; 2435 int num = Atomic::add(1, &cnt); 2436 2437 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2438 os::get_temp_directory(), os::current_process_id(), num); 2439 unlink(buf); 2440 2441 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2442 2443 if (fd != -1) { 2444 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2445 if (rv != (off_t)-1) { 2446 if (::write(fd, "", 1) == 1) { 2447 mmap(base, size, 2448 PROT_READ|PROT_WRITE|PROT_EXEC, 2449 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2450 } 2451 } 2452 ::close(fd); 2453 unlink(buf); 2454 } 2455 } 2456 2457 // NOTE: Linux kernel does not really reserve the pages for us. 2458 // All it does is to check if there are enough free pages 2459 // left at the time of mmap(). This could be a potential 2460 // problem. 2461 bool os::commit_memory(char* addr, size_t size, bool exec) { 2462 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2463 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2464 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2465 return res != (uintptr_t) MAP_FAILED; 2466 } 2467 2468 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint, 2469 bool exec) { 2470 return commit_memory(addr, size, exec); 2471 } 2472 2473 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { } 2474 2475 void os::free_memory(char *addr, size_t bytes) { 2476 ::mmap(addr, bytes, PROT_READ | PROT_WRITE, 2477 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2478 } 2479 2480 void os::numa_make_global(char *addr, size_t bytes) { 2481 Linux::numa_interleave_memory(addr, bytes); 2482 } 2483 2484 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2485 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2486 } 2487 2488 bool os::numa_topology_changed() { return false; } 2489 2490 size_t os::numa_get_groups_num() { 2491 int max_node = Linux::numa_max_node(); 2492 return max_node > 0 ? max_node + 1 : 1; 2493 } 2494 2495 int os::numa_get_group_id() { 2496 int cpu_id = Linux::sched_getcpu(); 2497 if (cpu_id != -1) { 2498 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2499 if (lgrp_id != -1) { 2500 return lgrp_id; 2501 } 2502 } 2503 return 0; 2504 } 2505 2506 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2507 for (size_t i = 0; i < size; i++) { 2508 ids[i] = i; 2509 } 2510 return size; 2511 } 2512 2513 bool os::get_page_info(char *start, page_info* info) { 2514 return false; 2515 } 2516 2517 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) { 2518 return end; 2519 } 2520 2521 // Something to do with the numa-aware allocator needs these symbols 2522 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2523 extern "C" JNIEXPORT void numa_error(char *where) { } 2524 extern "C" JNIEXPORT int fork1() { return fork(); } 2525 2526 2527 // If we are running with libnuma version > 2, then we should 2528 // be trying to use symbols with versions 1.1 2529 // If we are running with earlier version, which did not have symbol versions, 2530 // we should use the base version. 2531 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2532 void *f = dlvsym(handle, name, "libnuma_1.1"); 2533 if (f == NULL) { 2534 f = dlsym(handle, name); 2535 } 2536 return f; 2537 } 2538 2539 bool os::Linux::libnuma_init() { 2540 // sched_getcpu() should be in libc. 2541 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2542 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2543 2544 if (sched_getcpu() != -1) { // Does it work? 2545 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2546 if (handle != NULL) { 2547 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2548 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2549 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2550 libnuma_dlsym(handle, "numa_max_node"))); 2551 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2552 libnuma_dlsym(handle, "numa_available"))); 2553 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2554 libnuma_dlsym(handle, "numa_tonode_memory"))); 2555 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2556 libnuma_dlsym(handle, "numa_interleave_memory"))); 2557 2558 2559 if (numa_available() != -1) { 2560 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2561 // Create a cpu -> node mapping 2562 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true); 2563 rebuild_cpu_to_node_map(); 2564 return true; 2565 } 2566 } 2567 } 2568 return false; 2569 } 2570 2571 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2572 // The table is later used in get_node_by_cpu(). 2573 void os::Linux::rebuild_cpu_to_node_map() { 2574 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2575 // in libnuma (possible values are starting from 16, 2576 // and continuing up with every other power of 2, but less 2577 // than the maximum number of CPUs supported by kernel), and 2578 // is a subject to change (in libnuma version 2 the requirements 2579 // are more reasonable) we'll just hardcode the number they use 2580 // in the library. 2581 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2582 2583 size_t cpu_num = os::active_processor_count(); 2584 size_t cpu_map_size = NCPUS / BitsPerCLong; 2585 size_t cpu_map_valid_size = 2586 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2587 2588 cpu_to_node()->clear(); 2589 cpu_to_node()->at_grow(cpu_num - 1); 2590 size_t node_num = numa_get_groups_num(); 2591 2592 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size); 2593 for (size_t i = 0; i < node_num; i++) { 2594 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2595 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2596 if (cpu_map[j] != 0) { 2597 for (size_t k = 0; k < BitsPerCLong; k++) { 2598 if (cpu_map[j] & (1UL << k)) { 2599 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2600 } 2601 } 2602 } 2603 } 2604 } 2605 } 2606 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2607 } 2608 2609 int os::Linux::get_node_by_cpu(int cpu_id) { 2610 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2611 return cpu_to_node()->at(cpu_id); 2612 } 2613 return -1; 2614 } 2615 2616 GrowableArray<int>* os::Linux::_cpu_to_node; 2617 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2618 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2619 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2620 os::Linux::numa_available_func_t os::Linux::_numa_available; 2621 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2622 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2623 unsigned long* os::Linux::_numa_all_nodes; 2624 2625 bool os::uncommit_memory(char* addr, size_t size) { 2626 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2627 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2628 return res != (uintptr_t) MAP_FAILED; 2629 } 2630 2631 // Linux uses a growable mapping for the stack, and if the mapping for 2632 // the stack guard pages is not removed when we detach a thread the 2633 // stack cannot grow beyond the pages where the stack guard was 2634 // mapped. If at some point later in the process the stack expands to 2635 // that point, the Linux kernel cannot expand the stack any further 2636 // because the guard pages are in the way, and a segfault occurs. 2637 // 2638 // However, it's essential not to split the stack region by unmapping 2639 // a region (leaving a hole) that's already part of the stack mapping, 2640 // so if the stack mapping has already grown beyond the guard pages at 2641 // the time we create them, we have to truncate the stack mapping. 2642 // So, we need to know the extent of the stack mapping when 2643 // create_stack_guard_pages() is called. 2644 2645 // Find the bounds of the stack mapping. Return true for success. 2646 // 2647 // We only need this for stacks that are growable: at the time of 2648 // writing thread stacks don't use growable mappings (i.e. those 2649 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2650 // only applies to the main thread. 2651 static bool 2652 get_stack_bounds(uintptr_t *bottom, uintptr_t *top) 2653 { 2654 FILE *f = fopen("/proc/self/maps", "r"); 2655 if (f == NULL) 2656 return false; 2657 2658 while (!feof(f)) { 2659 size_t dummy; 2660 char *str = NULL; 2661 ssize_t len = getline(&str, &dummy, f); 2662 if (len == -1) { 2663 fclose(f); 2664 return false; 2665 } 2666 2667 if (len > 0 && str[len-1] == '\n') { 2668 str[len-1] = 0; 2669 len--; 2670 } 2671 2672 static const char *stack_str = "[stack]"; 2673 if (len > (ssize_t)strlen(stack_str) 2674 && (strcmp(str + len - strlen(stack_str), stack_str) == 0)) { 2675 if (sscanf(str, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) { 2676 uintptr_t sp = (uintptr_t)__builtin_frame_address(0); 2677 if (sp >= *bottom && sp <= *top) { 2678 free(str); 2679 fclose(f); 2680 return true; 2681 } 2682 } 2683 } 2684 free(str); 2685 } 2686 fclose(f); 2687 return false; 2688 } 2689 2690 // If the (growable) stack mapping already extends beyond the point 2691 // where we're going to put our guard pages, truncate the mapping at 2692 // that point by munmap()ping it. This ensures that when we later 2693 // munmap() the guard pages we don't leave a hole in the stack 2694 // mapping. This only affects the main/initial thread, but guard 2695 // against future OS changes 2696 bool os::create_stack_guard_pages(char* addr, size_t size) { 2697 uintptr_t stack_extent, stack_base; 2698 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2699 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2700 assert(os::Linux::is_initial_thread(), 2701 "growable stack in non-initial thread"); 2702 if (stack_extent < (uintptr_t)addr) 2703 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent); 2704 } 2705 2706 return os::commit_memory(addr, size); 2707 } 2708 2709 // If this is a growable mapping, remove the guard pages entirely by 2710 // munmap()ping them. If not, just call uncommit_memory(). This only 2711 // affects the main/initial thread, but guard against future OS changes 2712 bool os::remove_stack_guard_pages(char* addr, size_t size) { 2713 uintptr_t stack_extent, stack_base; 2714 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2715 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2716 assert(os::Linux::is_initial_thread(), 2717 "growable stack in non-initial thread"); 2718 2719 return ::munmap(addr, size) == 0; 2720 } 2721 2722 return os::uncommit_memory(addr, size); 2723 } 2724 2725 static address _highest_vm_reserved_address = NULL; 2726 2727 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 2728 // at 'requested_addr'. If there are existing memory mappings at the same 2729 // location, however, they will be overwritten. If 'fixed' is false, 2730 // 'requested_addr' is only treated as a hint, the return value may or 2731 // may not start from the requested address. Unlike Linux mmap(), this 2732 // function returns NULL to indicate failure. 2733 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 2734 char * addr; 2735 int flags; 2736 2737 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 2738 if (fixed) { 2739 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 2740 flags |= MAP_FIXED; 2741 } 2742 2743 // Map uncommitted pages PROT_READ and PROT_WRITE, change access 2744 // to PROT_EXEC if executable when we commit the page. 2745 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE, 2746 flags, -1, 0); 2747 2748 if (addr != MAP_FAILED) { 2749 // anon_mmap() should only get called during VM initialization, 2750 // don't need lock (actually we can skip locking even it can be called 2751 // from multiple threads, because _highest_vm_reserved_address is just a 2752 // hint about the upper limit of non-stack memory regions.) 2753 if ((address)addr + bytes > _highest_vm_reserved_address) { 2754 _highest_vm_reserved_address = (address)addr + bytes; 2755 } 2756 } 2757 2758 return addr == MAP_FAILED ? NULL : addr; 2759 } 2760 2761 // Don't update _highest_vm_reserved_address, because there might be memory 2762 // regions above addr + size. If so, releasing a memory region only creates 2763 // a hole in the address space, it doesn't help prevent heap-stack collision. 2764 // 2765 static int anon_munmap(char * addr, size_t size) { 2766 return ::munmap(addr, size) == 0; 2767 } 2768 2769 char* os::reserve_memory(size_t bytes, char* requested_addr, 2770 size_t alignment_hint) { 2771 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 2772 } 2773 2774 bool os::release_memory(char* addr, size_t size) { 2775 return anon_munmap(addr, size); 2776 } 2777 2778 static address highest_vm_reserved_address() { 2779 return _highest_vm_reserved_address; 2780 } 2781 2782 static bool linux_mprotect(char* addr, size_t size, int prot) { 2783 // Linux wants the mprotect address argument to be page aligned. 2784 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 2785 2786 // According to SUSv3, mprotect() should only be used with mappings 2787 // established by mmap(), and mmap() always maps whole pages. Unaligned 2788 // 'addr' likely indicates problem in the VM (e.g. trying to change 2789 // protection of malloc'ed or statically allocated memory). Check the 2790 // caller if you hit this assert. 2791 assert(addr == bottom, "sanity check"); 2792 2793 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 2794 return ::mprotect(bottom, size, prot) == 0; 2795 } 2796 2797 // Set protections specified 2798 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 2799 bool is_committed) { 2800 unsigned int p = 0; 2801 switch (prot) { 2802 case MEM_PROT_NONE: p = PROT_NONE; break; 2803 case MEM_PROT_READ: p = PROT_READ; break; 2804 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 2805 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 2806 default: 2807 ShouldNotReachHere(); 2808 } 2809 // is_committed is unused. 2810 return linux_mprotect(addr, bytes, p); 2811 } 2812 2813 bool os::guard_memory(char* addr, size_t size) { 2814 return linux_mprotect(addr, size, PROT_NONE); 2815 } 2816 2817 bool os::unguard_memory(char* addr, size_t size) { 2818 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 2819 } 2820 2821 /* 2822 * Set the coredump_filter bits to include largepages in core dump (bit 6) 2823 * 2824 * From the coredump_filter documentation: 2825 * 2826 * - (bit 0) anonymous private memory 2827 * - (bit 1) anonymous shared memory 2828 * - (bit 2) file-backed private memory 2829 * - (bit 3) file-backed shared memory 2830 * - (bit 4) ELF header pages in file-backed private memory areas (it is 2831 * effective only if the bit 2 is cleared) 2832 * - (bit 5) hugetlb private memory 2833 * - (bit 6) hugetlb shared memory 2834 */ 2835 static void set_coredump_filter(void) { 2836 FILE *f; 2837 long cdm; 2838 2839 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 2840 return; 2841 } 2842 2843 if (fscanf(f, "%lx", &cdm) != 1) { 2844 fclose(f); 2845 return; 2846 } 2847 2848 rewind(f); 2849 2850 if ((cdm & LARGEPAGES_BIT) == 0) { 2851 cdm |= LARGEPAGES_BIT; 2852 fprintf(f, "%#lx", cdm); 2853 } 2854 2855 fclose(f); 2856 } 2857 2858 // Large page support 2859 2860 static size_t _large_page_size = 0; 2861 2862 bool os::large_page_init() { 2863 if (!UseLargePages) return false; 2864 2865 if (LargePageSizeInBytes) { 2866 _large_page_size = LargePageSizeInBytes; 2867 } else { 2868 // large_page_size on Linux is used to round up heap size. x86 uses either 2869 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 2870 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 2871 // page as large as 256M. 2872 // 2873 // Here we try to figure out page size by parsing /proc/meminfo and looking 2874 // for a line with the following format: 2875 // Hugepagesize: 2048 kB 2876 // 2877 // If we can't determine the value (e.g. /proc is not mounted, or the text 2878 // format has been changed), we'll use the largest page size supported by 2879 // the processor. 2880 2881 #ifndef ZERO 2882 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 2883 ARM_ONLY(2 * M) PPC_ONLY(4 * M); 2884 #endif // ZERO 2885 2886 FILE *fp = fopen("/proc/meminfo", "r"); 2887 if (fp) { 2888 while (!feof(fp)) { 2889 int x = 0; 2890 char buf[16]; 2891 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 2892 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 2893 _large_page_size = x * K; 2894 break; 2895 } 2896 } else { 2897 // skip to next line 2898 for (;;) { 2899 int ch = fgetc(fp); 2900 if (ch == EOF || ch == (int)'\n') break; 2901 } 2902 } 2903 } 2904 fclose(fp); 2905 } 2906 } 2907 2908 const size_t default_page_size = (size_t)Linux::page_size(); 2909 if (_large_page_size > default_page_size) { 2910 _page_sizes[0] = _large_page_size; 2911 _page_sizes[1] = default_page_size; 2912 _page_sizes[2] = 0; 2913 } 2914 2915 set_coredump_filter(); 2916 2917 // Large page support is available on 2.6 or newer kernel, some vendors 2918 // (e.g. Redhat) have backported it to their 2.4 based distributions. 2919 // We optimistically assume the support is available. If later it turns out 2920 // not true, VM will automatically switch to use regular page size. 2921 return true; 2922 } 2923 2924 #ifndef SHM_HUGETLB 2925 #define SHM_HUGETLB 04000 2926 #endif 2927 2928 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) { 2929 // "exec" is passed in but not used. Creating the shared image for 2930 // the code cache doesn't have an SHM_X executable permission to check. 2931 assert(UseLargePages, "only for large pages"); 2932 2933 key_t key = IPC_PRIVATE; 2934 char *addr; 2935 2936 bool warn_on_failure = UseLargePages && 2937 (!FLAG_IS_DEFAULT(UseLargePages) || 2938 !FLAG_IS_DEFAULT(LargePageSizeInBytes) 2939 ); 2940 char msg[128]; 2941 2942 // Create a large shared memory region to attach to based on size. 2943 // Currently, size is the total size of the heap 2944 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 2945 if (shmid == -1) { 2946 // Possible reasons for shmget failure: 2947 // 1. shmmax is too small for Java heap. 2948 // > check shmmax value: cat /proc/sys/kernel/shmmax 2949 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 2950 // 2. not enough large page memory. 2951 // > check available large pages: cat /proc/meminfo 2952 // > increase amount of large pages: 2953 // echo new_value > /proc/sys/vm/nr_hugepages 2954 // Note 1: different Linux may use different name for this property, 2955 // e.g. on Redhat AS-3 it is "hugetlb_pool". 2956 // Note 2: it's possible there's enough physical memory available but 2957 // they are so fragmented after a long run that they can't 2958 // coalesce into large pages. Try to reserve large pages when 2959 // the system is still "fresh". 2960 if (warn_on_failure) { 2961 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 2962 warning(msg); 2963 } 2964 return NULL; 2965 } 2966 2967 // attach to the region 2968 addr = (char*)shmat(shmid, req_addr, 0); 2969 int err = errno; 2970 2971 // Remove shmid. If shmat() is successful, the actual shared memory segment 2972 // will be deleted when it's detached by shmdt() or when the process 2973 // terminates. If shmat() is not successful this will remove the shared 2974 // segment immediately. 2975 shmctl(shmid, IPC_RMID, NULL); 2976 2977 if ((intptr_t)addr == -1) { 2978 if (warn_on_failure) { 2979 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 2980 warning(msg); 2981 } 2982 return NULL; 2983 } 2984 2985 return addr; 2986 } 2987 2988 bool os::release_memory_special(char* base, size_t bytes) { 2989 // detaching the SHM segment will also delete it, see reserve_memory_special() 2990 int rslt = shmdt(base); 2991 return rslt == 0; 2992 } 2993 2994 size_t os::large_page_size() { 2995 return _large_page_size; 2996 } 2997 2998 // Linux does not support anonymous mmap with large page memory. The only way 2999 // to reserve large page memory without file backing is through SysV shared 3000 // memory API. The entire memory region is committed and pinned upfront. 3001 // Hopefully this will change in the future... 3002 bool os::can_commit_large_page_memory() { 3003 return false; 3004 } 3005 3006 bool os::can_execute_large_page_memory() { 3007 return false; 3008 } 3009 3010 // Reserve memory at an arbitrary address, only if that area is 3011 // available (and not reserved for something else). 3012 3013 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3014 const int max_tries = 10; 3015 char* base[max_tries]; 3016 size_t size[max_tries]; 3017 const size_t gap = 0x000000; 3018 3019 // Assert only that the size is a multiple of the page size, since 3020 // that's all that mmap requires, and since that's all we really know 3021 // about at this low abstraction level. If we need higher alignment, 3022 // we can either pass an alignment to this method or verify alignment 3023 // in one of the methods further up the call chain. See bug 5044738. 3024 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3025 3026 // Repeatedly allocate blocks until the block is allocated at the 3027 // right spot. Give up after max_tries. Note that reserve_memory() will 3028 // automatically update _highest_vm_reserved_address if the call is 3029 // successful. The variable tracks the highest memory address every reserved 3030 // by JVM. It is used to detect heap-stack collision if running with 3031 // fixed-stack LinuxThreads. Because here we may attempt to reserve more 3032 // space than needed, it could confuse the collision detecting code. To 3033 // solve the problem, save current _highest_vm_reserved_address and 3034 // calculate the correct value before return. 3035 address old_highest = _highest_vm_reserved_address; 3036 3037 // Linux mmap allows caller to pass an address as hint; give it a try first, 3038 // if kernel honors the hint then we can return immediately. 3039 char * addr = anon_mmap(requested_addr, bytes, false); 3040 if (addr == requested_addr) { 3041 return requested_addr; 3042 } 3043 3044 if (addr != NULL) { 3045 // mmap() is successful but it fails to reserve at the requested address 3046 anon_munmap(addr, bytes); 3047 } 3048 3049 int i; 3050 for (i = 0; i < max_tries; ++i) { 3051 base[i] = reserve_memory(bytes); 3052 3053 if (base[i] != NULL) { 3054 // Is this the block we wanted? 3055 if (base[i] == requested_addr) { 3056 size[i] = bytes; 3057 break; 3058 } 3059 3060 // Does this overlap the block we wanted? Give back the overlapped 3061 // parts and try again. 3062 3063 size_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3064 if (top_overlap >= 0 && top_overlap < bytes) { 3065 unmap_memory(base[i], top_overlap); 3066 base[i] += top_overlap; 3067 size[i] = bytes - top_overlap; 3068 } else { 3069 size_t bottom_overlap = base[i] + bytes - requested_addr; 3070 if (bottom_overlap >= 0 && bottom_overlap < bytes) { 3071 unmap_memory(requested_addr, bottom_overlap); 3072 size[i] = bytes - bottom_overlap; 3073 } else { 3074 size[i] = bytes; 3075 } 3076 } 3077 } 3078 } 3079 3080 // Give back the unused reserved pieces. 3081 3082 for (int j = 0; j < i; ++j) { 3083 if (base[j] != NULL) { 3084 unmap_memory(base[j], size[j]); 3085 } 3086 } 3087 3088 if (i < max_tries) { 3089 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes); 3090 return requested_addr; 3091 } else { 3092 _highest_vm_reserved_address = old_highest; 3093 return NULL; 3094 } 3095 } 3096 3097 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3098 return ::read(fd, buf, nBytes); 3099 } 3100 3101 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation. 3102 // Solaris uses poll(), linux uses park(). 3103 // Poll() is likely a better choice, assuming that Thread.interrupt() 3104 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with 3105 // SIGSEGV, see 4355769. 3106 3107 const int NANOSECS_PER_MILLISECS = 1000000; 3108 3109 int os::sleep(Thread* thread, jlong millis, bool interruptible) { 3110 assert(thread == Thread::current(), "thread consistency check"); 3111 3112 ParkEvent * const slp = thread->_SleepEvent ; 3113 slp->reset() ; 3114 OrderAccess::fence() ; 3115 3116 if (interruptible) { 3117 jlong prevtime = javaTimeNanos(); 3118 3119 for (;;) { 3120 if (os::is_interrupted(thread, true)) { 3121 return OS_INTRPT; 3122 } 3123 3124 jlong newtime = javaTimeNanos(); 3125 3126 if (newtime - prevtime < 0) { 3127 // time moving backwards, should only happen if no monotonic clock 3128 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3129 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3130 } else { 3131 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS; 3132 } 3133 3134 if(millis <= 0) { 3135 return OS_OK; 3136 } 3137 3138 prevtime = newtime; 3139 3140 { 3141 assert(thread->is_Java_thread(), "sanity check"); 3142 JavaThread *jt = (JavaThread *) thread; 3143 ThreadBlockInVM tbivm(jt); 3144 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 3145 3146 jt->set_suspend_equivalent(); 3147 // cleared by handle_special_suspend_equivalent_condition() or 3148 // java_suspend_self() via check_and_wait_while_suspended() 3149 3150 slp->park(millis); 3151 3152 // were we externally suspended while we were waiting? 3153 jt->check_and_wait_while_suspended(); 3154 } 3155 } 3156 } else { 3157 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 3158 jlong prevtime = javaTimeNanos(); 3159 3160 for (;;) { 3161 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 3162 // the 1st iteration ... 3163 jlong newtime = javaTimeNanos(); 3164 3165 if (newtime - prevtime < 0) { 3166 // time moving backwards, should only happen if no monotonic clock 3167 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3168 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3169 } else { 3170 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS; 3171 } 3172 3173 if(millis <= 0) break ; 3174 3175 prevtime = newtime; 3176 slp->park(millis); 3177 } 3178 return OS_OK ; 3179 } 3180 } 3181 3182 int os::naked_sleep() { 3183 // %% make the sleep time an integer flag. for now use 1 millisec. 3184 return os::sleep(Thread::current(), 1, false); 3185 } 3186 3187 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3188 void os::infinite_sleep() { 3189 while (true) { // sleep forever ... 3190 ::sleep(100); // ... 100 seconds at a time 3191 } 3192 } 3193 3194 // Used to convert frequent JVM_Yield() to nops 3195 bool os::dont_yield() { 3196 return DontYieldALot; 3197 } 3198 3199 void os::yield() { 3200 sched_yield(); 3201 } 3202 3203 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;} 3204 3205 void os::yield_all(int attempts) { 3206 // Yields to all threads, including threads with lower priorities 3207 // Threads on Linux are all with same priority. The Solaris style 3208 // os::yield_all() with nanosleep(1ms) is not necessary. 3209 sched_yield(); 3210 } 3211 3212 // Called from the tight loops to possibly influence time-sharing heuristics 3213 void os::loop_breaker(int attempts) { 3214 os::yield_all(attempts); 3215 } 3216 3217 //////////////////////////////////////////////////////////////////////////////// 3218 // thread priority support 3219 3220 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3221 // only supports dynamic priority, static priority must be zero. For real-time 3222 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3223 // However, for large multi-threaded applications, SCHED_RR is not only slower 3224 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3225 // of 5 runs - Sep 2005). 3226 // 3227 // The following code actually changes the niceness of kernel-thread/LWP. It 3228 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3229 // not the entire user process, and user level threads are 1:1 mapped to kernel 3230 // threads. It has always been the case, but could change in the future. For 3231 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3232 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3233 3234 int os::java_to_os_priority[MaxPriority + 1] = { 3235 19, // 0 Entry should never be used 3236 3237 4, // 1 MinPriority 3238 3, // 2 3239 2, // 3 3240 3241 1, // 4 3242 0, // 5 NormPriority 3243 -1, // 6 3244 3245 -2, // 7 3246 -3, // 8 3247 -4, // 9 NearMaxPriority 3248 3249 -5 // 10 MaxPriority 3250 }; 3251 3252 static int prio_init() { 3253 if (ThreadPriorityPolicy == 1) { 3254 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3255 // if effective uid is not root. Perhaps, a more elegant way of doing 3256 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3257 if (geteuid() != 0) { 3258 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3259 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3260 } 3261 ThreadPriorityPolicy = 0; 3262 } 3263 } 3264 return 0; 3265 } 3266 3267 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3268 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK; 3269 3270 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3271 return (ret == 0) ? OS_OK : OS_ERR; 3272 } 3273 3274 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) { 3275 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) { 3276 *priority_ptr = java_to_os_priority[NormPriority]; 3277 return OS_OK; 3278 } 3279 3280 errno = 0; 3281 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3282 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3283 } 3284 3285 // Hint to the underlying OS that a task switch would not be good. 3286 // Void return because it's a hint and can fail. 3287 void os::hint_no_preempt() {} 3288 3289 //////////////////////////////////////////////////////////////////////////////// 3290 // suspend/resume support 3291 3292 // the low-level signal-based suspend/resume support is a remnant from the 3293 // old VM-suspension that used to be for java-suspension, safepoints etc, 3294 // within hotspot. Now there is a single use-case for this: 3295 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3296 // that runs in the watcher thread. 3297 // The remaining code is greatly simplified from the more general suspension 3298 // code that used to be used. 3299 // 3300 // The protocol is quite simple: 3301 // - suspend: 3302 // - sends a signal to the target thread 3303 // - polls the suspend state of the osthread using a yield loop 3304 // - target thread signal handler (SR_handler) sets suspend state 3305 // and blocks in sigsuspend until continued 3306 // - resume: 3307 // - sets target osthread state to continue 3308 // - sends signal to end the sigsuspend loop in the SR_handler 3309 // 3310 // Note that the SR_lock plays no role in this suspend/resume protocol. 3311 // 3312 3313 static void resume_clear_context(OSThread *osthread) { 3314 osthread->set_ucontext(NULL); 3315 osthread->set_siginfo(NULL); 3316 3317 // notify the suspend action is completed, we have now resumed 3318 osthread->sr.clear_suspended(); 3319 } 3320 3321 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) { 3322 osthread->set_ucontext(context); 3323 osthread->set_siginfo(siginfo); 3324 } 3325 3326 // 3327 // Handler function invoked when a thread's execution is suspended or 3328 // resumed. We have to be careful that only async-safe functions are 3329 // called here (Note: most pthread functions are not async safe and 3330 // should be avoided.) 3331 // 3332 // Note: sigwait() is a more natural fit than sigsuspend() from an 3333 // interface point of view, but sigwait() prevents the signal hander 3334 // from being run. libpthread would get very confused by not having 3335 // its signal handlers run and prevents sigwait()'s use with the 3336 // mutex granting granting signal. 3337 // 3338 // Currently only ever called on the VMThread 3339 // 3340 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3341 // Save and restore errno to avoid confusing native code with EINTR 3342 // after sigsuspend. 3343 int old_errno = errno; 3344 3345 Thread* thread = Thread::current(); 3346 OSThread* osthread = thread->osthread(); 3347 assert(thread->is_VM_thread(), "Must be VMThread"); 3348 // read current suspend action 3349 int action = osthread->sr.suspend_action(); 3350 if (action == SR_SUSPEND) { 3351 suspend_save_context(osthread, siginfo, context); 3352 3353 // Notify the suspend action is about to be completed. do_suspend() 3354 // waits until SR_SUSPENDED is set and then returns. We will wait 3355 // here for a resume signal and that completes the suspend-other 3356 // action. do_suspend/do_resume is always called as a pair from 3357 // the same thread - so there are no races 3358 3359 // notify the caller 3360 osthread->sr.set_suspended(); 3361 3362 sigset_t suspend_set; // signals for sigsuspend() 3363 3364 // get current set of blocked signals and unblock resume signal 3365 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3366 sigdelset(&suspend_set, SR_signum); 3367 3368 // wait here until we are resumed 3369 do { 3370 sigsuspend(&suspend_set); 3371 // ignore all returns until we get a resume signal 3372 } while (osthread->sr.suspend_action() != SR_CONTINUE); 3373 3374 resume_clear_context(osthread); 3375 3376 } else { 3377 assert(action == SR_CONTINUE, "unexpected sr action"); 3378 // nothing special to do - just leave the handler 3379 } 3380 3381 errno = old_errno; 3382 } 3383 3384 3385 static int SR_initialize() { 3386 struct sigaction act; 3387 char *s; 3388 /* Get signal number to use for suspend/resume */ 3389 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3390 int sig = ::strtol(s, 0, 10); 3391 if (sig > 0 || sig < _NSIG) { 3392 SR_signum = sig; 3393 } 3394 } 3395 3396 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 3397 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 3398 3399 sigemptyset(&SR_sigset); 3400 sigaddset(&SR_sigset, SR_signum); 3401 3402 /* Set up signal handler for suspend/resume */ 3403 act.sa_flags = SA_RESTART|SA_SIGINFO; 3404 act.sa_handler = (void (*)(int)) SR_handler; 3405 3406 // SR_signum is blocked by default. 3407 // 4528190 - We also need to block pthread restart signal (32 on all 3408 // supported Linux platforms). Note that LinuxThreads need to block 3409 // this signal for all threads to work properly. So we don't have 3410 // to use hard-coded signal number when setting up the mask. 3411 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 3412 3413 if (sigaction(SR_signum, &act, 0) == -1) { 3414 return -1; 3415 } 3416 3417 // Save signal flag 3418 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 3419 return 0; 3420 } 3421 3422 static int SR_finalize() { 3423 return 0; 3424 } 3425 3426 3427 // returns true on success and false on error - really an error is fatal 3428 // but this seems the normal response to library errors 3429 static bool do_suspend(OSThread* osthread) { 3430 // mark as suspended and send signal 3431 osthread->sr.set_suspend_action(SR_SUSPEND); 3432 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3433 assert_status(status == 0, status, "pthread_kill"); 3434 3435 // check status and wait until notified of suspension 3436 if (status == 0) { 3437 for (int i = 0; !osthread->sr.is_suspended(); i++) { 3438 os::yield_all(i); 3439 } 3440 osthread->sr.set_suspend_action(SR_NONE); 3441 return true; 3442 } 3443 else { 3444 osthread->sr.set_suspend_action(SR_NONE); 3445 return false; 3446 } 3447 } 3448 3449 static void do_resume(OSThread* osthread) { 3450 assert(osthread->sr.is_suspended(), "thread should be suspended"); 3451 osthread->sr.set_suspend_action(SR_CONTINUE); 3452 3453 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3454 assert_status(status == 0, status, "pthread_kill"); 3455 // check status and wait unit notified of resumption 3456 if (status == 0) { 3457 for (int i = 0; osthread->sr.is_suspended(); i++) { 3458 os::yield_all(i); 3459 } 3460 } 3461 osthread->sr.set_suspend_action(SR_NONE); 3462 } 3463 3464 //////////////////////////////////////////////////////////////////////////////// 3465 // interrupt support 3466 3467 void os::interrupt(Thread* thread) { 3468 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3469 "possibility of dangling Thread pointer"); 3470 3471 OSThread* osthread = thread->osthread(); 3472 3473 if (!osthread->interrupted()) { 3474 osthread->set_interrupted(true); 3475 // More than one thread can get here with the same value of osthread, 3476 // resulting in multiple notifications. We do, however, want the store 3477 // to interrupted() to be visible to other threads before we execute unpark(). 3478 OrderAccess::fence(); 3479 ParkEvent * const slp = thread->_SleepEvent ; 3480 if (slp != NULL) slp->unpark() ; 3481 } 3482 3483 // For JSR166. Unpark even if interrupt status already was set 3484 if (thread->is_Java_thread()) 3485 ((JavaThread*)thread)->parker()->unpark(); 3486 3487 ParkEvent * ev = thread->_ParkEvent ; 3488 if (ev != NULL) ev->unpark() ; 3489 3490 } 3491 3492 bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 3493 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3494 "possibility of dangling Thread pointer"); 3495 3496 OSThread* osthread = thread->osthread(); 3497 3498 bool interrupted = osthread->interrupted(); 3499 3500 if (interrupted && clear_interrupted) { 3501 osthread->set_interrupted(false); 3502 // consider thread->_SleepEvent->reset() ... optional optimization 3503 } 3504 3505 return interrupted; 3506 } 3507 3508 /////////////////////////////////////////////////////////////////////////////////// 3509 // signal handling (except suspend/resume) 3510 3511 // This routine may be used by user applications as a "hook" to catch signals. 3512 // The user-defined signal handler must pass unrecognized signals to this 3513 // routine, and if it returns true (non-zero), then the signal handler must 3514 // return immediately. If the flag "abort_if_unrecognized" is true, then this 3515 // routine will never retun false (zero), but instead will execute a VM panic 3516 // routine kill the process. 3517 // 3518 // If this routine returns false, it is OK to call it again. This allows 3519 // the user-defined signal handler to perform checks either before or after 3520 // the VM performs its own checks. Naturally, the user code would be making 3521 // a serious error if it tried to handle an exception (such as a null check 3522 // or breakpoint) that the VM was generating for its own correct operation. 3523 // 3524 // This routine may recognize any of the following kinds of signals: 3525 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 3526 // It should be consulted by handlers for any of those signals. 3527 // 3528 // The caller of this routine must pass in the three arguments supplied 3529 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 3530 // field of the structure passed to sigaction(). This routine assumes that 3531 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 3532 // 3533 // Note that the VM will print warnings if it detects conflicting signal 3534 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 3535 // 3536 extern "C" JNIEXPORT int 3537 JVM_handle_linux_signal(int signo, siginfo_t* siginfo, 3538 void* ucontext, int abort_if_unrecognized); 3539 3540 void signalHandler(int sig, siginfo_t* info, void* uc) { 3541 assert(info != NULL && uc != NULL, "it must be old kernel"); 3542 JVM_handle_linux_signal(sig, info, uc, true); 3543 } 3544 3545 3546 // This boolean allows users to forward their own non-matching signals 3547 // to JVM_handle_linux_signal, harmlessly. 3548 bool os::Linux::signal_handlers_are_installed = false; 3549 3550 // For signal-chaining 3551 struct sigaction os::Linux::sigact[MAXSIGNUM]; 3552 unsigned int os::Linux::sigs = 0; 3553 bool os::Linux::libjsig_is_loaded = false; 3554 typedef struct sigaction *(*get_signal_t)(int); 3555 get_signal_t os::Linux::get_signal_action = NULL; 3556 3557 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 3558 struct sigaction *actp = NULL; 3559 3560 if (libjsig_is_loaded) { 3561 // Retrieve the old signal handler from libjsig 3562 actp = (*get_signal_action)(sig); 3563 } 3564 if (actp == NULL) { 3565 // Retrieve the preinstalled signal handler from jvm 3566 actp = get_preinstalled_handler(sig); 3567 } 3568 3569 return actp; 3570 } 3571 3572 static bool call_chained_handler(struct sigaction *actp, int sig, 3573 siginfo_t *siginfo, void *context) { 3574 // Call the old signal handler 3575 if (actp->sa_handler == SIG_DFL) { 3576 // It's more reasonable to let jvm treat it as an unexpected exception 3577 // instead of taking the default action. 3578 return false; 3579 } else if (actp->sa_handler != SIG_IGN) { 3580 if ((actp->sa_flags & SA_NODEFER) == 0) { 3581 // automaticlly block the signal 3582 sigaddset(&(actp->sa_mask), sig); 3583 } 3584 3585 sa_handler_t hand; 3586 sa_sigaction_t sa; 3587 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 3588 // retrieve the chained handler 3589 if (siginfo_flag_set) { 3590 sa = actp->sa_sigaction; 3591 } else { 3592 hand = actp->sa_handler; 3593 } 3594 3595 if ((actp->sa_flags & SA_RESETHAND) != 0) { 3596 actp->sa_handler = SIG_DFL; 3597 } 3598 3599 // try to honor the signal mask 3600 sigset_t oset; 3601 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 3602 3603 // call into the chained handler 3604 if (siginfo_flag_set) { 3605 (*sa)(sig, siginfo, context); 3606 } else { 3607 (*hand)(sig); 3608 } 3609 3610 // restore the signal mask 3611 pthread_sigmask(SIG_SETMASK, &oset, 0); 3612 } 3613 // Tell jvm's signal handler the signal is taken care of. 3614 return true; 3615 } 3616 3617 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 3618 bool chained = false; 3619 // signal-chaining 3620 if (UseSignalChaining) { 3621 struct sigaction *actp = get_chained_signal_action(sig); 3622 if (actp != NULL) { 3623 chained = call_chained_handler(actp, sig, siginfo, context); 3624 } 3625 } 3626 return chained; 3627 } 3628 3629 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 3630 if ((( (unsigned int)1 << sig ) & sigs) != 0) { 3631 return &sigact[sig]; 3632 } 3633 return NULL; 3634 } 3635 3636 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 3637 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3638 sigact[sig] = oldAct; 3639 sigs |= (unsigned int)1 << sig; 3640 } 3641 3642 // for diagnostic 3643 int os::Linux::sigflags[MAXSIGNUM]; 3644 3645 int os::Linux::get_our_sigflags(int sig) { 3646 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3647 return sigflags[sig]; 3648 } 3649 3650 void os::Linux::set_our_sigflags(int sig, int flags) { 3651 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3652 sigflags[sig] = flags; 3653 } 3654 3655 void os::Linux::set_signal_handler(int sig, bool set_installed) { 3656 // Check for overwrite. 3657 struct sigaction oldAct; 3658 sigaction(sig, (struct sigaction*)NULL, &oldAct); 3659 3660 void* oldhand = oldAct.sa_sigaction 3661 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3662 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3663 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 3664 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 3665 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 3666 if (AllowUserSignalHandlers || !set_installed) { 3667 // Do not overwrite; user takes responsibility to forward to us. 3668 return; 3669 } else if (UseSignalChaining) { 3670 // save the old handler in jvm 3671 save_preinstalled_handler(sig, oldAct); 3672 // libjsig also interposes the sigaction() call below and saves the 3673 // old sigaction on it own. 3674 } else { 3675 fatal(err_msg("Encountered unexpected pre-existing sigaction handler " 3676 "%#lx for signal %d.", (long)oldhand, sig)); 3677 } 3678 } 3679 3680 struct sigaction sigAct; 3681 sigfillset(&(sigAct.sa_mask)); 3682 sigAct.sa_handler = SIG_DFL; 3683 if (!set_installed) { 3684 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3685 } else { 3686 sigAct.sa_sigaction = signalHandler; 3687 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3688 } 3689 // Save flags, which are set by ours 3690 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3691 sigflags[sig] = sigAct.sa_flags; 3692 3693 int ret = sigaction(sig, &sigAct, &oldAct); 3694 assert(ret == 0, "check"); 3695 3696 void* oldhand2 = oldAct.sa_sigaction 3697 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3698 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3699 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 3700 } 3701 3702 // install signal handlers for signals that HotSpot needs to 3703 // handle in order to support Java-level exception handling. 3704 3705 void os::Linux::install_signal_handlers() { 3706 if (!signal_handlers_are_installed) { 3707 signal_handlers_are_installed = true; 3708 3709 // signal-chaining 3710 typedef void (*signal_setting_t)(); 3711 signal_setting_t begin_signal_setting = NULL; 3712 signal_setting_t end_signal_setting = NULL; 3713 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3714 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 3715 if (begin_signal_setting != NULL) { 3716 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3717 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 3718 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 3719 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 3720 libjsig_is_loaded = true; 3721 assert(UseSignalChaining, "should enable signal-chaining"); 3722 } 3723 if (libjsig_is_loaded) { 3724 // Tell libjsig jvm is setting signal handlers 3725 (*begin_signal_setting)(); 3726 } 3727 3728 set_signal_handler(SIGSEGV, true); 3729 set_signal_handler(SIGPIPE, true); 3730 set_signal_handler(SIGBUS, true); 3731 set_signal_handler(SIGILL, true); 3732 set_signal_handler(SIGFPE, true); 3733 set_signal_handler(SIGXFSZ, true); 3734 3735 if (libjsig_is_loaded) { 3736 // Tell libjsig jvm finishes setting signal handlers 3737 (*end_signal_setting)(); 3738 } 3739 3740 // We don't activate signal checker if libjsig is in place, we trust ourselves 3741 // and if UserSignalHandler is installed all bets are off 3742 if (CheckJNICalls) { 3743 if (libjsig_is_loaded) { 3744 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 3745 check_signals = false; 3746 } 3747 if (AllowUserSignalHandlers) { 3748 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 3749 check_signals = false; 3750 } 3751 } 3752 } 3753 } 3754 3755 // This is the fastest way to get thread cpu time on Linux. 3756 // Returns cpu time (user+sys) for any thread, not only for current. 3757 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 3758 // It might work on 2.6.10+ with a special kernel/glibc patch. 3759 // For reference, please, see IEEE Std 1003.1-2004: 3760 // http://www.unix.org/single_unix_specification 3761 3762 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 3763 struct timespec tp; 3764 int rc = os::Linux::clock_gettime(clockid, &tp); 3765 assert(rc == 0, "clock_gettime is expected to return 0 code"); 3766 3767 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec; 3768 } 3769 3770 ///// 3771 // glibc on Linux platform uses non-documented flag 3772 // to indicate, that some special sort of signal 3773 // trampoline is used. 3774 // We will never set this flag, and we should 3775 // ignore this flag in our diagnostic 3776 #ifdef SIGNIFICANT_SIGNAL_MASK 3777 #undef SIGNIFICANT_SIGNAL_MASK 3778 #endif 3779 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 3780 3781 static const char* get_signal_handler_name(address handler, 3782 char* buf, int buflen) { 3783 int offset; 3784 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 3785 if (found) { 3786 // skip directory names 3787 const char *p1, *p2; 3788 p1 = buf; 3789 size_t len = strlen(os::file_separator()); 3790 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 3791 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 3792 } else { 3793 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 3794 } 3795 return buf; 3796 } 3797 3798 static void print_signal_handler(outputStream* st, int sig, 3799 char* buf, size_t buflen) { 3800 struct sigaction sa; 3801 3802 sigaction(sig, NULL, &sa); 3803 3804 // See comment for SIGNIFICANT_SIGNAL_MASK define 3805 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3806 3807 st->print("%s: ", os::exception_name(sig, buf, buflen)); 3808 3809 address handler = (sa.sa_flags & SA_SIGINFO) 3810 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 3811 : CAST_FROM_FN_PTR(address, sa.sa_handler); 3812 3813 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 3814 st->print("SIG_DFL"); 3815 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 3816 st->print("SIG_IGN"); 3817 } else { 3818 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 3819 } 3820 3821 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask); 3822 3823 address rh = VMError::get_resetted_sighandler(sig); 3824 // May be, handler was resetted by VMError? 3825 if(rh != NULL) { 3826 handler = rh; 3827 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 3828 } 3829 3830 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags); 3831 3832 // Check: is it our handler? 3833 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 3834 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 3835 // It is our signal handler 3836 // check for flags, reset system-used one! 3837 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 3838 st->print( 3839 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 3840 os::Linux::get_our_sigflags(sig)); 3841 } 3842 } 3843 st->cr(); 3844 } 3845 3846 3847 #define DO_SIGNAL_CHECK(sig) \ 3848 if (!sigismember(&check_signal_done, sig)) \ 3849 os::Linux::check_signal_handler(sig) 3850 3851 // This method is a periodic task to check for misbehaving JNI applications 3852 // under CheckJNI, we can add any periodic checks here 3853 3854 void os::run_periodic_checks() { 3855 3856 if (check_signals == false) return; 3857 3858 // SEGV and BUS if overridden could potentially prevent 3859 // generation of hs*.log in the event of a crash, debugging 3860 // such a case can be very challenging, so we absolutely 3861 // check the following for a good measure: 3862 DO_SIGNAL_CHECK(SIGSEGV); 3863 DO_SIGNAL_CHECK(SIGILL); 3864 DO_SIGNAL_CHECK(SIGFPE); 3865 DO_SIGNAL_CHECK(SIGBUS); 3866 DO_SIGNAL_CHECK(SIGPIPE); 3867 DO_SIGNAL_CHECK(SIGXFSZ); 3868 3869 3870 // ReduceSignalUsage allows the user to override these handlers 3871 // see comments at the very top and jvm_solaris.h 3872 if (!ReduceSignalUsage) { 3873 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 3874 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 3875 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 3876 DO_SIGNAL_CHECK(BREAK_SIGNAL); 3877 } 3878 3879 DO_SIGNAL_CHECK(SR_signum); 3880 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 3881 } 3882 3883 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 3884 3885 static os_sigaction_t os_sigaction = NULL; 3886 3887 void os::Linux::check_signal_handler(int sig) { 3888 char buf[O_BUFLEN]; 3889 address jvmHandler = NULL; 3890 3891 3892 struct sigaction act; 3893 if (os_sigaction == NULL) { 3894 // only trust the default sigaction, in case it has been interposed 3895 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 3896 if (os_sigaction == NULL) return; 3897 } 3898 3899 os_sigaction(sig, (struct sigaction*)NULL, &act); 3900 3901 3902 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3903 3904 address thisHandler = (act.sa_flags & SA_SIGINFO) 3905 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 3906 : CAST_FROM_FN_PTR(address, act.sa_handler) ; 3907 3908 3909 switch(sig) { 3910 case SIGSEGV: 3911 case SIGBUS: 3912 case SIGFPE: 3913 case SIGPIPE: 3914 case SIGILL: 3915 case SIGXFSZ: 3916 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 3917 break; 3918 3919 case SHUTDOWN1_SIGNAL: 3920 case SHUTDOWN2_SIGNAL: 3921 case SHUTDOWN3_SIGNAL: 3922 case BREAK_SIGNAL: 3923 jvmHandler = (address)user_handler(); 3924 break; 3925 3926 case INTERRUPT_SIGNAL: 3927 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 3928 break; 3929 3930 default: 3931 if (sig == SR_signum) { 3932 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 3933 } else { 3934 return; 3935 } 3936 break; 3937 } 3938 3939 if (thisHandler != jvmHandler) { 3940 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 3941 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 3942 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 3943 // No need to check this sig any longer 3944 sigaddset(&check_signal_done, sig); 3945 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 3946 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 3947 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 3948 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 3949 // No need to check this sig any longer 3950 sigaddset(&check_signal_done, sig); 3951 } 3952 3953 // Dump all the signal 3954 if (sigismember(&check_signal_done, sig)) { 3955 print_signal_handlers(tty, buf, O_BUFLEN); 3956 } 3957 } 3958 3959 extern void report_error(char* file_name, int line_no, char* title, char* format, ...); 3960 3961 extern bool signal_name(int signo, char* buf, size_t len); 3962 3963 const char* os::exception_name(int exception_code, char* buf, size_t size) { 3964 if (0 < exception_code && exception_code <= SIGRTMAX) { 3965 // signal 3966 if (!signal_name(exception_code, buf, size)) { 3967 jio_snprintf(buf, size, "SIG%d", exception_code); 3968 } 3969 return buf; 3970 } else { 3971 return NULL; 3972 } 3973 } 3974 3975 // this is called _before_ the most of global arguments have been parsed 3976 void os::init(void) { 3977 char dummy; /* used to get a guess on initial stack address */ 3978 // first_hrtime = gethrtime(); 3979 3980 // With LinuxThreads the JavaMain thread pid (primordial thread) 3981 // is different than the pid of the java launcher thread. 3982 // So, on Linux, the launcher thread pid is passed to the VM 3983 // via the sun.java.launcher.pid property. 3984 // Use this property instead of getpid() if it was correctly passed. 3985 // See bug 6351349. 3986 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid(); 3987 3988 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid(); 3989 3990 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 3991 3992 init_random(1234567); 3993 3994 ThreadCritical::initialize(); 3995 3996 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 3997 if (Linux::page_size() == -1) { 3998 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)", 3999 strerror(errno))); 4000 } 4001 init_page_sizes((size_t) Linux::page_size()); 4002 4003 Linux::initialize_system_info(); 4004 4005 // main_thread points to the aboriginal thread 4006 Linux::_main_thread = pthread_self(); 4007 4008 Linux::clock_init(); 4009 initial_time_count = os::elapsed_counter(); 4010 pthread_mutex_init(&dl_mutex, NULL); 4011 } 4012 4013 // To install functions for atexit system call 4014 extern "C" { 4015 static void perfMemory_exit_helper() { 4016 perfMemory_exit(); 4017 } 4018 } 4019 4020 // this is called _after_ the global arguments have been parsed 4021 jint os::init_2(void) 4022 { 4023 Linux::fast_thread_clock_init(); 4024 4025 // Allocate a single page and mark it as readable for safepoint polling 4026 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4027 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" ); 4028 4029 os::set_polling_page( polling_page ); 4030 4031 #ifndef PRODUCT 4032 if(Verbose && PrintMiscellaneous) 4033 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page); 4034 #endif 4035 4036 if (!UseMembar) { 4037 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4038 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page"); 4039 os::set_memory_serialize_page( mem_serialize_page ); 4040 4041 #ifndef PRODUCT 4042 if(Verbose && PrintMiscellaneous) 4043 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page); 4044 #endif 4045 } 4046 4047 FLAG_SET_DEFAULT(UseLargePages, os::large_page_init()); 4048 4049 // initialize suspend/resume support - must do this before signal_sets_init() 4050 if (SR_initialize() != 0) { 4051 perror("SR_initialize failed"); 4052 return JNI_ERR; 4053 } 4054 4055 Linux::signal_sets_init(); 4056 Linux::install_signal_handlers(); 4057 4058 // Check minimum allowable stack size for thread creation and to initialize 4059 // the java system classes, including StackOverflowError - depends on page 4060 // size. Add a page for compiler2 recursion in main thread. 4061 // Add in 2*BytesPerWord times page size to account for VM stack during 4062 // class initialization depending on 32 or 64 bit VM. 4063 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4064 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+ 4065 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size()); 4066 4067 size_t threadStackSizeInBytes = ThreadStackSize * K; 4068 if (threadStackSizeInBytes != 0 && 4069 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4070 tty->print_cr("\nThe stack size specified is too small, " 4071 "Specify at least %dk", 4072 os::Linux::min_stack_allowed/ K); 4073 return JNI_ERR; 4074 } 4075 4076 // Make the stack size a multiple of the page size so that 4077 // the yellow/red zones can be guarded. 4078 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4079 vm_page_size())); 4080 4081 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4082 4083 Linux::libpthread_init(); 4084 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4085 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n", 4086 Linux::glibc_version(), Linux::libpthread_version(), 4087 Linux::is_floating_stack() ? "floating stack" : "fixed stack"); 4088 } 4089 4090 if (UseNUMA) { 4091 if (!Linux::libnuma_init()) { 4092 UseNUMA = false; 4093 } else { 4094 if ((Linux::numa_max_node() < 1)) { 4095 // There's only one node(they start from 0), disable NUMA. 4096 UseNUMA = false; 4097 } 4098 } 4099 if (!UseNUMA && ForceNUMA) { 4100 UseNUMA = true; 4101 } 4102 } 4103 4104 if (MaxFDLimit) { 4105 // set the number of file descriptors to max. print out error 4106 // if getrlimit/setrlimit fails but continue regardless. 4107 struct rlimit nbr_files; 4108 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4109 if (status != 0) { 4110 if (PrintMiscellaneous && (Verbose || WizardMode)) 4111 perror("os::init_2 getrlimit failed"); 4112 } else { 4113 nbr_files.rlim_cur = nbr_files.rlim_max; 4114 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4115 if (status != 0) { 4116 if (PrintMiscellaneous && (Verbose || WizardMode)) 4117 perror("os::init_2 setrlimit failed"); 4118 } 4119 } 4120 } 4121 4122 // Initialize lock used to serialize thread creation (see os::create_thread) 4123 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4124 4125 // at-exit methods are called in the reverse order of their registration. 4126 // atexit functions are called on return from main or as a result of a 4127 // call to exit(3C). There can be only 32 of these functions registered 4128 // and atexit() does not set errno. 4129 4130 if (PerfAllowAtExitRegistration) { 4131 // only register atexit functions if PerfAllowAtExitRegistration is set. 4132 // atexit functions can be delayed until process exit time, which 4133 // can be problematic for embedded VM situations. Embedded VMs should 4134 // call DestroyJavaVM() to assure that VM resources are released. 4135 4136 // note: perfMemory_exit_helper atexit function may be removed in 4137 // the future if the appropriate cleanup code can be added to the 4138 // VM_Exit VMOperation's doit method. 4139 if (atexit(perfMemory_exit_helper) != 0) { 4140 warning("os::init2 atexit(perfMemory_exit_helper) failed"); 4141 } 4142 } 4143 4144 // initialize thread priority policy 4145 prio_init(); 4146 4147 return JNI_OK; 4148 } 4149 4150 // this is called at the end of vm_initialization 4151 void os::init_3(void) { } 4152 4153 // Mark the polling page as unreadable 4154 void os::make_polling_page_unreadable(void) { 4155 if( !guard_memory((char*)_polling_page, Linux::page_size()) ) 4156 fatal("Could not disable polling page"); 4157 }; 4158 4159 // Mark the polling page as readable 4160 void os::make_polling_page_readable(void) { 4161 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4162 fatal("Could not enable polling page"); 4163 } 4164 }; 4165 4166 int os::active_processor_count() { 4167 // Linux doesn't yet have a (official) notion of processor sets, 4168 // so just return the number of online processors. 4169 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4170 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4171 return online_cpus; 4172 } 4173 4174 bool os::distribute_processes(uint length, uint* distribution) { 4175 // Not yet implemented. 4176 return false; 4177 } 4178 4179 bool os::bind_to_processor(uint processor_id) { 4180 // Not yet implemented. 4181 return false; 4182 } 4183 4184 /// 4185 4186 // Suspends the target using the signal mechanism and then grabs the PC before 4187 // resuming the target. Used by the flat-profiler only 4188 ExtendedPC os::get_thread_pc(Thread* thread) { 4189 // Make sure that it is called by the watcher for the VMThread 4190 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4191 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4192 4193 ExtendedPC epc; 4194 4195 OSThread* osthread = thread->osthread(); 4196 if (do_suspend(osthread)) { 4197 if (osthread->ucontext() != NULL) { 4198 epc = os::Linux::ucontext_get_pc(osthread->ucontext()); 4199 } else { 4200 // NULL context is unexpected, double-check this is the VMThread 4201 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4202 } 4203 do_resume(osthread); 4204 } 4205 // failure means pthread_kill failed for some reason - arguably this is 4206 // a fatal problem, but such problems are ignored elsewhere 4207 4208 return epc; 4209 } 4210 4211 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime) 4212 { 4213 if (is_NPTL()) { 4214 return pthread_cond_timedwait(_cond, _mutex, _abstime); 4215 } else { 4216 #ifndef IA64 4217 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control 4218 // word back to default 64bit precision if condvar is signaled. Java 4219 // wants 53bit precision. Save and restore current value. 4220 int fpu = get_fpu_control_word(); 4221 #endif // IA64 4222 int status = pthread_cond_timedwait(_cond, _mutex, _abstime); 4223 #ifndef IA64 4224 set_fpu_control_word(fpu); 4225 #endif // IA64 4226 return status; 4227 } 4228 } 4229 4230 //////////////////////////////////////////////////////////////////////////////// 4231 // debug support 4232 4233 static address same_page(address x, address y) { 4234 int page_bits = -os::vm_page_size(); 4235 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits)) 4236 return x; 4237 else if (x > y) 4238 return (address)(intptr_t(y) | ~page_bits) + 1; 4239 else 4240 return (address)(intptr_t(y) & page_bits); 4241 } 4242 4243 bool os::find(address addr, outputStream* st) { 4244 Dl_info dlinfo; 4245 memset(&dlinfo, 0, sizeof(dlinfo)); 4246 if (dladdr(addr, &dlinfo)) { 4247 st->print(PTR_FORMAT ": ", addr); 4248 if (dlinfo.dli_sname != NULL) { 4249 st->print("%s+%#x", dlinfo.dli_sname, 4250 addr - (intptr_t)dlinfo.dli_saddr); 4251 } else if (dlinfo.dli_fname) { 4252 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 4253 } else { 4254 st->print("<absolute address>"); 4255 } 4256 if (dlinfo.dli_fname) { 4257 st->print(" in %s", dlinfo.dli_fname); 4258 } 4259 if (dlinfo.dli_fbase) { 4260 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 4261 } 4262 st->cr(); 4263 4264 if (Verbose) { 4265 // decode some bytes around the PC 4266 address begin = same_page(addr-40, addr); 4267 address end = same_page(addr+40, addr); 4268 address lowest = (address) dlinfo.dli_sname; 4269 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4270 if (begin < lowest) begin = lowest; 4271 Dl_info dlinfo2; 4272 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr 4273 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) 4274 end = (address) dlinfo2.dli_saddr; 4275 Disassembler::decode(begin, end, st); 4276 } 4277 return true; 4278 } 4279 return false; 4280 } 4281 4282 //////////////////////////////////////////////////////////////////////////////// 4283 // misc 4284 4285 // This does not do anything on Linux. This is basically a hook for being 4286 // able to use structured exception handling (thread-local exception filters) 4287 // on, e.g., Win32. 4288 void 4289 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 4290 JavaCallArguments* args, Thread* thread) { 4291 f(value, method, args, thread); 4292 } 4293 4294 void os::print_statistics() { 4295 } 4296 4297 int os::message_box(const char* title, const char* message) { 4298 int i; 4299 fdStream err(defaultStream::error_fd()); 4300 for (i = 0; i < 78; i++) err.print_raw("="); 4301 err.cr(); 4302 err.print_raw_cr(title); 4303 for (i = 0; i < 78; i++) err.print_raw("-"); 4304 err.cr(); 4305 err.print_raw_cr(message); 4306 for (i = 0; i < 78; i++) err.print_raw("="); 4307 err.cr(); 4308 4309 char buf[16]; 4310 // Prevent process from exiting upon "read error" without consuming all CPU 4311 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4312 4313 return buf[0] == 'y' || buf[0] == 'Y'; 4314 } 4315 4316 int os::stat(const char *path, struct stat *sbuf) { 4317 char pathbuf[MAX_PATH]; 4318 if (strlen(path) > MAX_PATH - 1) { 4319 errno = ENAMETOOLONG; 4320 return -1; 4321 } 4322 os::native_path(strcpy(pathbuf, path)); 4323 return ::stat(pathbuf, sbuf); 4324 } 4325 4326 bool os::check_heap(bool force) { 4327 return true; 4328 } 4329 4330 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) { 4331 return ::vsnprintf(buf, count, format, args); 4332 } 4333 4334 // Is a (classpath) directory empty? 4335 bool os::dir_is_empty(const char* path) { 4336 DIR *dir = NULL; 4337 struct dirent *ptr; 4338 4339 dir = opendir(path); 4340 if (dir == NULL) return true; 4341 4342 /* Scan the directory */ 4343 bool result = true; 4344 char buf[sizeof(struct dirent) + MAX_PATH]; 4345 while (result && (ptr = ::readdir(dir)) != NULL) { 4346 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 4347 result = false; 4348 } 4349 } 4350 closedir(dir); 4351 return result; 4352 } 4353 4354 // This code originates from JDK's sysOpen and open64_w 4355 // from src/solaris/hpi/src/system_md.c 4356 4357 #ifndef O_DELETE 4358 #define O_DELETE 0x10000 4359 #endif 4360 4361 // Open a file. Unlink the file immediately after open returns 4362 // if the specified oflag has the O_DELETE flag set. 4363 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c 4364 4365 int os::open(const char *path, int oflag, int mode) { 4366 4367 if (strlen(path) > MAX_PATH - 1) { 4368 errno = ENAMETOOLONG; 4369 return -1; 4370 } 4371 int fd; 4372 int o_delete = (oflag & O_DELETE); 4373 oflag = oflag & ~O_DELETE; 4374 4375 fd = ::open64(path, oflag, mode); 4376 if (fd == -1) return -1; 4377 4378 //If the open succeeded, the file might still be a directory 4379 { 4380 struct stat64 buf64; 4381 int ret = ::fstat64(fd, &buf64); 4382 int st_mode = buf64.st_mode; 4383 4384 if (ret != -1) { 4385 if ((st_mode & S_IFMT) == S_IFDIR) { 4386 errno = EISDIR; 4387 ::close(fd); 4388 return -1; 4389 } 4390 } else { 4391 ::close(fd); 4392 return -1; 4393 } 4394 } 4395 4396 /* 4397 * All file descriptors that are opened in the JVM and not 4398 * specifically destined for a subprocess should have the 4399 * close-on-exec flag set. If we don't set it, then careless 3rd 4400 * party native code might fork and exec without closing all 4401 * appropriate file descriptors (e.g. as we do in closeDescriptors in 4402 * UNIXProcess.c), and this in turn might: 4403 * 4404 * - cause end-of-file to fail to be detected on some file 4405 * descriptors, resulting in mysterious hangs, or 4406 * 4407 * - might cause an fopen in the subprocess to fail on a system 4408 * suffering from bug 1085341. 4409 * 4410 * (Yes, the default setting of the close-on-exec flag is a Unix 4411 * design flaw) 4412 * 4413 * See: 4414 * 1085341: 32-bit stdio routines should support file descriptors >255 4415 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed 4416 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 4417 */ 4418 #ifdef FD_CLOEXEC 4419 { 4420 int flags = ::fcntl(fd, F_GETFD); 4421 if (flags != -1) 4422 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 4423 } 4424 #endif 4425 4426 if (o_delete != 0) { 4427 ::unlink(path); 4428 } 4429 return fd; 4430 } 4431 4432 4433 // create binary file, rewriting existing file if required 4434 int os::create_binary_file(const char* path, bool rewrite_existing) { 4435 int oflags = O_WRONLY | O_CREAT; 4436 if (!rewrite_existing) { 4437 oflags |= O_EXCL; 4438 } 4439 return ::open64(path, oflags, S_IREAD | S_IWRITE); 4440 } 4441 4442 // return current position of file pointer 4443 jlong os::current_file_offset(int fd) { 4444 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 4445 } 4446 4447 // move file pointer to the specified offset 4448 jlong os::seek_to_file_offset(int fd, jlong offset) { 4449 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 4450 } 4451 4452 // This code originates from JDK's sysAvailable 4453 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 4454 4455 int os::available(int fd, jlong *bytes) { 4456 jlong cur, end; 4457 int mode; 4458 struct stat64 buf64; 4459 4460 if (::fstat64(fd, &buf64) >= 0) { 4461 mode = buf64.st_mode; 4462 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 4463 /* 4464 * XXX: is the following call interruptible? If so, this might 4465 * need to go through the INTERRUPT_IO() wrapper as for other 4466 * blocking, interruptible calls in this file. 4467 */ 4468 int n; 4469 if (::ioctl(fd, FIONREAD, &n) >= 0) { 4470 *bytes = n; 4471 return 1; 4472 } 4473 } 4474 } 4475 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 4476 return 0; 4477 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 4478 return 0; 4479 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 4480 return 0; 4481 } 4482 *bytes = end - cur; 4483 return 1; 4484 } 4485 4486 int os::socket_available(int fd, jint *pbytes) { 4487 // Linux doc says EINTR not returned, unlike Solaris 4488 int ret = ::ioctl(fd, FIONREAD, pbytes); 4489 4490 //%% note ioctl can return 0 when successful, JVM_SocketAvailable 4491 // is expected to return 0 on failure and 1 on success to the jdk. 4492 return (ret < 0) ? 0 : 1; 4493 } 4494 4495 // Map a block of memory. 4496 char* os::map_memory(int fd, const char* file_name, size_t file_offset, 4497 char *addr, size_t bytes, bool read_only, 4498 bool allow_exec) { 4499 int prot; 4500 int flags; 4501 4502 if (read_only) { 4503 prot = PROT_READ; 4504 flags = MAP_SHARED; 4505 } else { 4506 prot = PROT_READ | PROT_WRITE; 4507 flags = MAP_PRIVATE; 4508 } 4509 4510 if (allow_exec) { 4511 prot |= PROT_EXEC; 4512 } 4513 4514 if (addr != NULL) { 4515 flags |= MAP_FIXED; 4516 } 4517 4518 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 4519 fd, file_offset); 4520 if (mapped_address == MAP_FAILED) { 4521 return NULL; 4522 } 4523 return mapped_address; 4524 } 4525 4526 4527 // Remap a block of memory. 4528 char* os::remap_memory(int fd, const char* file_name, size_t file_offset, 4529 char *addr, size_t bytes, bool read_only, 4530 bool allow_exec) { 4531 // same as map_memory() on this OS 4532 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 4533 allow_exec); 4534 } 4535 4536 4537 // Unmap a block of memory. 4538 bool os::unmap_memory(char* addr, size_t bytes) { 4539 return munmap(addr, bytes) == 0; 4540 } 4541 4542 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 4543 4544 static clockid_t thread_cpu_clockid(Thread* thread) { 4545 pthread_t tid = thread->osthread()->pthread_id(); 4546 clockid_t clockid; 4547 4548 // Get thread clockid 4549 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 4550 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 4551 return clockid; 4552 } 4553 4554 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 4555 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 4556 // of a thread. 4557 // 4558 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 4559 // the fast estimate available on the platform. 4560 4561 jlong os::current_thread_cpu_time() { 4562 if (os::Linux::supports_fast_thread_cpu_time()) { 4563 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4564 } else { 4565 // return user + sys since the cost is the same 4566 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 4567 } 4568 } 4569 4570 jlong os::thread_cpu_time(Thread* thread) { 4571 // consistent with what current_thread_cpu_time() returns 4572 if (os::Linux::supports_fast_thread_cpu_time()) { 4573 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4574 } else { 4575 return slow_thread_cpu_time(thread, true /* user + sys */); 4576 } 4577 } 4578 4579 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 4580 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4581 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4582 } else { 4583 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 4584 } 4585 } 4586 4587 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4588 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4589 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4590 } else { 4591 return slow_thread_cpu_time(thread, user_sys_cpu_time); 4592 } 4593 } 4594 4595 // 4596 // -1 on error. 4597 // 4598 4599 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4600 static bool proc_pid_cpu_avail = true; 4601 static bool proc_task_unchecked = true; 4602 static const char *proc_stat_path = "/proc/%d/stat"; 4603 pid_t tid = thread->osthread()->thread_id(); 4604 int i; 4605 char *s; 4606 char stat[2048]; 4607 int statlen; 4608 char proc_name[64]; 4609 int count; 4610 long sys_time, user_time; 4611 char string[64]; 4612 char cdummy; 4613 int idummy; 4614 long ldummy; 4615 FILE *fp; 4616 4617 // We first try accessing /proc/<pid>/cpu since this is faster to 4618 // process. If this file is not present (linux kernels 2.5 and above) 4619 // then we open /proc/<pid>/stat. 4620 if ( proc_pid_cpu_avail ) { 4621 sprintf(proc_name, "/proc/%d/cpu", tid); 4622 fp = fopen(proc_name, "r"); 4623 if ( fp != NULL ) { 4624 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time); 4625 fclose(fp); 4626 if ( count != 3 ) return -1; 4627 4628 if (user_sys_cpu_time) { 4629 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4630 } else { 4631 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4632 } 4633 } 4634 else proc_pid_cpu_avail = false; 4635 } 4636 4637 // The /proc/<tid>/stat aggregates per-process usage on 4638 // new Linux kernels 2.6+ where NPTL is supported. 4639 // The /proc/self/task/<tid>/stat still has the per-thread usage. 4640 // See bug 6328462. 4641 // There can be no directory /proc/self/task on kernels 2.4 with NPTL 4642 // and possibly in some other cases, so we check its availability. 4643 if (proc_task_unchecked && os::Linux::is_NPTL()) { 4644 // This is executed only once 4645 proc_task_unchecked = false; 4646 fp = fopen("/proc/self/task", "r"); 4647 if (fp != NULL) { 4648 proc_stat_path = "/proc/self/task/%d/stat"; 4649 fclose(fp); 4650 } 4651 } 4652 4653 sprintf(proc_name, proc_stat_path, tid); 4654 fp = fopen(proc_name, "r"); 4655 if ( fp == NULL ) return -1; 4656 statlen = fread(stat, 1, 2047, fp); 4657 stat[statlen] = '\0'; 4658 fclose(fp); 4659 4660 // Skip pid and the command string. Note that we could be dealing with 4661 // weird command names, e.g. user could decide to rename java launcher 4662 // to "java 1.4.2 :)", then the stat file would look like 4663 // 1234 (java 1.4.2 :)) R ... ... 4664 // We don't really need to know the command string, just find the last 4665 // occurrence of ")" and then start parsing from there. See bug 4726580. 4666 s = strrchr(stat, ')'); 4667 i = 0; 4668 if (s == NULL ) return -1; 4669 4670 // Skip blank chars 4671 do s++; while (isspace(*s)); 4672 4673 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 4674 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 4675 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 4676 &user_time, &sys_time); 4677 if ( count != 13 ) return -1; 4678 if (user_sys_cpu_time) { 4679 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4680 } else { 4681 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4682 } 4683 } 4684 4685 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4686 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4687 info_ptr->may_skip_backward = false; // elapsed time not wall time 4688 info_ptr->may_skip_forward = false; // elapsed time not wall time 4689 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4690 } 4691 4692 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4693 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4694 info_ptr->may_skip_backward = false; // elapsed time not wall time 4695 info_ptr->may_skip_forward = false; // elapsed time not wall time 4696 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4697 } 4698 4699 bool os::is_thread_cpu_time_supported() { 4700 return true; 4701 } 4702 4703 // System loadavg support. Returns -1 if load average cannot be obtained. 4704 // Linux doesn't yet have a (official) notion of processor sets, 4705 // so just return the system wide load average. 4706 int os::loadavg(double loadavg[], int nelem) { 4707 return ::getloadavg(loadavg, nelem); 4708 } 4709 4710 void os::pause() { 4711 char filename[MAX_PATH]; 4712 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 4713 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 4714 } else { 4715 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 4716 } 4717 4718 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 4719 if (fd != -1) { 4720 struct stat buf; 4721 ::close(fd); 4722 while (::stat(filename, &buf) == 0) { 4723 (void)::poll(NULL, 0, 100); 4724 } 4725 } else { 4726 jio_fprintf(stderr, 4727 "Could not open pause file '%s', continuing immediately.\n", filename); 4728 } 4729 } 4730 4731 4732 // Refer to the comments in os_solaris.cpp park-unpark. 4733 // 4734 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 4735 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 4736 // For specifics regarding the bug see GLIBC BUGID 261237 : 4737 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 4738 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 4739 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 4740 // is used. (The simple C test-case provided in the GLIBC bug report manifests the 4741 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 4742 // and monitorenter when we're using 1-0 locking. All those operations may result in 4743 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 4744 // of libpthread avoids the problem, but isn't practical. 4745 // 4746 // Possible remedies: 4747 // 4748 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 4749 // This is palliative and probabilistic, however. If the thread is preempted 4750 // between the call to compute_abstime() and pthread_cond_timedwait(), more 4751 // than the minimum period may have passed, and the abstime may be stale (in the 4752 // past) resultin in a hang. Using this technique reduces the odds of a hang 4753 // but the JVM is still vulnerable, particularly on heavily loaded systems. 4754 // 4755 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 4756 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set 4757 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 4758 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant 4759 // thread. 4760 // 4761 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 4762 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 4763 // a timeout request to the chron thread and then blocking via pthread_cond_wait(). 4764 // This also works well. In fact it avoids kernel-level scalability impediments 4765 // on certain platforms that don't handle lots of active pthread_cond_timedwait() 4766 // timers in a graceful fashion. 4767 // 4768 // 4. When the abstime value is in the past it appears that control returns 4769 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 4770 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we 4771 // can avoid the problem by reinitializing the condvar -- by cond_destroy() 4772 // followed by cond_init() -- after all calls to pthread_cond_timedwait(). 4773 // It may be possible to avoid reinitialization by checking the return 4774 // value from pthread_cond_timedwait(). In addition to reinitializing the 4775 // condvar we must establish the invariant that cond_signal() is only called 4776 // within critical sections protected by the adjunct mutex. This prevents 4777 // cond_signal() from "seeing" a condvar that's in the midst of being 4778 // reinitialized or that is corrupt. Sadly, this invariant obviates the 4779 // desirable signal-after-unlock optimization that avoids futile context switching. 4780 // 4781 // I'm also concerned that some versions of NTPL might allocate an auxilliary 4782 // structure when a condvar is used or initialized. cond_destroy() would 4783 // release the helper structure. Our reinitialize-after-timedwait fix 4784 // put excessive stress on malloc/free and locks protecting the c-heap. 4785 // 4786 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 4787 // It may be possible to refine (4) by checking the kernel and NTPL verisons 4788 // and only enabling the work-around for vulnerable environments. 4789 4790 // utility to compute the abstime argument to timedwait: 4791 // millis is the relative timeout time 4792 // abstime will be the absolute timeout time 4793 // TODO: replace compute_abstime() with unpackTime() 4794 4795 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 4796 if (millis < 0) millis = 0; 4797 struct timeval now; 4798 int status = gettimeofday(&now, NULL); 4799 assert(status == 0, "gettimeofday"); 4800 jlong seconds = millis / 1000; 4801 millis %= 1000; 4802 if (seconds > 50000000) { // see man cond_timedwait(3T) 4803 seconds = 50000000; 4804 } 4805 abstime->tv_sec = now.tv_sec + seconds; 4806 long usec = now.tv_usec + millis * 1000; 4807 if (usec >= 1000000) { 4808 abstime->tv_sec += 1; 4809 usec -= 1000000; 4810 } 4811 abstime->tv_nsec = usec * 1000; 4812 return abstime; 4813 } 4814 4815 4816 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately. 4817 // Conceptually TryPark() should be equivalent to park(0). 4818 4819 int os::PlatformEvent::TryPark() { 4820 for (;;) { 4821 const int v = _Event ; 4822 guarantee ((v == 0) || (v == 1), "invariant") ; 4823 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ; 4824 } 4825 } 4826 4827 void os::PlatformEvent::park() { // AKA "down()" 4828 // Invariant: Only the thread associated with the Event/PlatformEvent 4829 // may call park(). 4830 // TODO: assert that _Assoc != NULL or _Assoc == Self 4831 int v ; 4832 for (;;) { 4833 v = _Event ; 4834 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 4835 } 4836 guarantee (v >= 0, "invariant") ; 4837 if (v == 0) { 4838 // Do this the hard way by blocking ... 4839 int status = pthread_mutex_lock(_mutex); 4840 assert_status(status == 0, status, "mutex_lock"); 4841 guarantee (_nParked == 0, "invariant") ; 4842 ++ _nParked ; 4843 while (_Event < 0) { 4844 status = pthread_cond_wait(_cond, _mutex); 4845 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 4846 // Treat this the same as if the wait was interrupted 4847 if (status == ETIME) { status = EINTR; } 4848 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 4849 } 4850 -- _nParked ; 4851 4852 // In theory we could move the ST of 0 into _Event past the unlock(), 4853 // but then we'd need a MEMBAR after the ST. 4854 _Event = 0 ; 4855 status = pthread_mutex_unlock(_mutex); 4856 assert_status(status == 0, status, "mutex_unlock"); 4857 } 4858 guarantee (_Event >= 0, "invariant") ; 4859 } 4860 4861 int os::PlatformEvent::park(jlong millis) { 4862 guarantee (_nParked == 0, "invariant") ; 4863 4864 int v ; 4865 for (;;) { 4866 v = _Event ; 4867 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 4868 } 4869 guarantee (v >= 0, "invariant") ; 4870 if (v != 0) return OS_OK ; 4871 4872 // We do this the hard way, by blocking the thread. 4873 // Consider enforcing a minimum timeout value. 4874 struct timespec abst; 4875 compute_abstime(&abst, millis); 4876 4877 int ret = OS_TIMEOUT; 4878 int status = pthread_mutex_lock(_mutex); 4879 assert_status(status == 0, status, "mutex_lock"); 4880 guarantee (_nParked == 0, "invariant") ; 4881 ++_nParked ; 4882 4883 // Object.wait(timo) will return because of 4884 // (a) notification 4885 // (b) timeout 4886 // (c) thread.interrupt 4887 // 4888 // Thread.interrupt and object.notify{All} both call Event::set. 4889 // That is, we treat thread.interrupt as a special case of notification. 4890 // The underlying Solaris implementation, cond_timedwait, admits 4891 // spurious/premature wakeups, but the JLS/JVM spec prevents the 4892 // JVM from making those visible to Java code. As such, we must 4893 // filter out spurious wakeups. We assume all ETIME returns are valid. 4894 // 4895 // TODO: properly differentiate simultaneous notify+interrupt. 4896 // In that case, we should propagate the notify to another waiter. 4897 4898 while (_Event < 0) { 4899 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst); 4900 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 4901 pthread_cond_destroy (_cond); 4902 pthread_cond_init (_cond, NULL) ; 4903 } 4904 assert_status(status == 0 || status == EINTR || 4905 status == ETIME || status == ETIMEDOUT, 4906 status, "cond_timedwait"); 4907 if (!FilterSpuriousWakeups) break ; // previous semantics 4908 if (status == ETIME || status == ETIMEDOUT) break ; 4909 // We consume and ignore EINTR and spurious wakeups. 4910 } 4911 --_nParked ; 4912 if (_Event >= 0) { 4913 ret = OS_OK; 4914 } 4915 _Event = 0 ; 4916 status = pthread_mutex_unlock(_mutex); 4917 assert_status(status == 0, status, "mutex_unlock"); 4918 assert (_nParked == 0, "invariant") ; 4919 return ret; 4920 } 4921 4922 void os::PlatformEvent::unpark() { 4923 int v, AnyWaiters ; 4924 for (;;) { 4925 v = _Event ; 4926 if (v > 0) { 4927 // The LD of _Event could have reordered or be satisfied 4928 // by a read-aside from this processor's write buffer. 4929 // To avoid problems execute a barrier and then 4930 // ratify the value. 4931 OrderAccess::fence() ; 4932 if (_Event == v) return ; 4933 continue ; 4934 } 4935 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ; 4936 } 4937 if (v < 0) { 4938 // Wait for the thread associated with the event to vacate 4939 int status = pthread_mutex_lock(_mutex); 4940 assert_status(status == 0, status, "mutex_lock"); 4941 AnyWaiters = _nParked ; 4942 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ; 4943 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 4944 AnyWaiters = 0 ; 4945 pthread_cond_signal (_cond); 4946 } 4947 status = pthread_mutex_unlock(_mutex); 4948 assert_status(status == 0, status, "mutex_unlock"); 4949 if (AnyWaiters != 0) { 4950 status = pthread_cond_signal(_cond); 4951 assert_status(status == 0, status, "cond_signal"); 4952 } 4953 } 4954 4955 // Note that we signal() _after dropping the lock for "immortal" Events. 4956 // This is safe and avoids a common class of futile wakeups. In rare 4957 // circumstances this can cause a thread to return prematurely from 4958 // cond_{timed}wait() but the spurious wakeup is benign and the victim will 4959 // simply re-test the condition and re-park itself. 4960 } 4961 4962 4963 // JSR166 4964 // ------------------------------------------------------- 4965 4966 /* 4967 * The solaris and linux implementations of park/unpark are fairly 4968 * conservative for now, but can be improved. They currently use a 4969 * mutex/condvar pair, plus a a count. 4970 * Park decrements count if > 0, else does a condvar wait. Unpark 4971 * sets count to 1 and signals condvar. Only one thread ever waits 4972 * on the condvar. Contention seen when trying to park implies that someone 4973 * is unparking you, so don't wait. And spurious returns are fine, so there 4974 * is no need to track notifications. 4975 */ 4976 4977 4978 #define NANOSECS_PER_SEC 1000000000 4979 #define NANOSECS_PER_MILLISEC 1000000 4980 #define MAX_SECS 100000000 4981 /* 4982 * This code is common to linux and solaris and will be moved to a 4983 * common place in dolphin. 4984 * 4985 * The passed in time value is either a relative time in nanoseconds 4986 * or an absolute time in milliseconds. Either way it has to be unpacked 4987 * into suitable seconds and nanoseconds components and stored in the 4988 * given timespec structure. 4989 * Given time is a 64-bit value and the time_t used in the timespec is only 4990 * a signed-32-bit value (except on 64-bit Linux) we have to watch for 4991 * overflow if times way in the future are given. Further on Solaris versions 4992 * prior to 10 there is a restriction (see cond_timedwait) that the specified 4993 * number of seconds, in abstime, is less than current_time + 100,000,000. 4994 * As it will be 28 years before "now + 100000000" will overflow we can 4995 * ignore overflow and just impose a hard-limit on seconds using the value 4996 * of "now + 100,000,000". This places a limit on the timeout of about 3.17 4997 * years from "now". 4998 */ 4999 5000 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5001 assert (time > 0, "convertTime"); 5002 5003 struct timeval now; 5004 int status = gettimeofday(&now, NULL); 5005 assert(status == 0, "gettimeofday"); 5006 5007 time_t max_secs = now.tv_sec + MAX_SECS; 5008 5009 if (isAbsolute) { 5010 jlong secs = time / 1000; 5011 if (secs > max_secs) { 5012 absTime->tv_sec = max_secs; 5013 } 5014 else { 5015 absTime->tv_sec = secs; 5016 } 5017 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5018 } 5019 else { 5020 jlong secs = time / NANOSECS_PER_SEC; 5021 if (secs >= MAX_SECS) { 5022 absTime->tv_sec = max_secs; 5023 absTime->tv_nsec = 0; 5024 } 5025 else { 5026 absTime->tv_sec = now.tv_sec + secs; 5027 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5028 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5029 absTime->tv_nsec -= NANOSECS_PER_SEC; 5030 ++absTime->tv_sec; // note: this must be <= max_secs 5031 } 5032 } 5033 } 5034 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5035 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5036 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5037 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5038 } 5039 5040 void Parker::park(bool isAbsolute, jlong time) { 5041 // Optional fast-path check: 5042 // Return immediately if a permit is available. 5043 if (_counter > 0) { 5044 _counter = 0 ; 5045 OrderAccess::fence(); 5046 return ; 5047 } 5048 5049 Thread* thread = Thread::current(); 5050 assert(thread->is_Java_thread(), "Must be JavaThread"); 5051 JavaThread *jt = (JavaThread *)thread; 5052 5053 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5054 // Check interrupt before trying to wait 5055 if (Thread::is_interrupted(thread, false)) { 5056 return; 5057 } 5058 5059 // Next, demultiplex/decode time arguments 5060 timespec absTime; 5061 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all 5062 return; 5063 } 5064 if (time > 0) { 5065 unpackTime(&absTime, isAbsolute, time); 5066 } 5067 5068 5069 // Enter safepoint region 5070 // Beware of deadlocks such as 6317397. 5071 // The per-thread Parker:: mutex is a classic leaf-lock. 5072 // In particular a thread must never block on the Threads_lock while 5073 // holding the Parker:: mutex. If safepoints are pending both the 5074 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5075 ThreadBlockInVM tbivm(jt); 5076 5077 // Don't wait if cannot get lock since interference arises from 5078 // unblocking. Also. check interrupt before trying wait 5079 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5080 return; 5081 } 5082 5083 int status ; 5084 if (_counter > 0) { // no wait needed 5085 _counter = 0; 5086 status = pthread_mutex_unlock(_mutex); 5087 assert (status == 0, "invariant") ; 5088 OrderAccess::fence(); 5089 return; 5090 } 5091 5092 #ifdef ASSERT 5093 // Don't catch signals while blocked; let the running threads have the signals. 5094 // (This allows a debugger to break into the running thread.) 5095 sigset_t oldsigs; 5096 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5097 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5098 #endif 5099 5100 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5101 jt->set_suspend_equivalent(); 5102 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5103 5104 if (time == 0) { 5105 status = pthread_cond_wait (_cond, _mutex) ; 5106 } else { 5107 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ; 5108 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5109 pthread_cond_destroy (_cond) ; 5110 pthread_cond_init (_cond, NULL); 5111 } 5112 } 5113 assert_status(status == 0 || status == EINTR || 5114 status == ETIME || status == ETIMEDOUT, 5115 status, "cond_timedwait"); 5116 5117 #ifdef ASSERT 5118 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5119 #endif 5120 5121 _counter = 0 ; 5122 status = pthread_mutex_unlock(_mutex) ; 5123 assert_status(status == 0, status, "invariant") ; 5124 // If externally suspended while waiting, re-suspend 5125 if (jt->handle_special_suspend_equivalent_condition()) { 5126 jt->java_suspend_self(); 5127 } 5128 5129 OrderAccess::fence(); 5130 } 5131 5132 void Parker::unpark() { 5133 int s, status ; 5134 status = pthread_mutex_lock(_mutex); 5135 assert (status == 0, "invariant") ; 5136 s = _counter; 5137 _counter = 1; 5138 if (s < 1) { 5139 if (WorkAroundNPTLTimedWaitHang) { 5140 status = pthread_cond_signal (_cond) ; 5141 assert (status == 0, "invariant") ; 5142 status = pthread_mutex_unlock(_mutex); 5143 assert (status == 0, "invariant") ; 5144 } else { 5145 status = pthread_mutex_unlock(_mutex); 5146 assert (status == 0, "invariant") ; 5147 status = pthread_cond_signal (_cond) ; 5148 assert (status == 0, "invariant") ; 5149 } 5150 } else { 5151 pthread_mutex_unlock(_mutex); 5152 assert (status == 0, "invariant") ; 5153 } 5154 } 5155 5156 5157 extern char** environ; 5158 5159 #ifndef __NR_fork 5160 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) 5161 #endif 5162 5163 #ifndef __NR_execve 5164 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) 5165 #endif 5166 5167 // Run the specified command in a separate process. Return its exit value, 5168 // or -1 on failure (e.g. can't fork a new process). 5169 // Unlike system(), this function can be called from signal handler. It 5170 // doesn't block SIGINT et al. 5171 int os::fork_and_exec(char* cmd) { 5172 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5173 5174 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run 5175 // pthread_atfork handlers and reset pthread library. All we need is a 5176 // separate process to execve. Make a direct syscall to fork process. 5177 // On IA64 there's no fork syscall, we have to use fork() and hope for 5178 // the best... 5179 pid_t pid = NOT_IA64(syscall(__NR_fork);) 5180 IA64_ONLY(fork();) 5181 5182 if (pid < 0) { 5183 // fork failed 5184 return -1; 5185 5186 } else if (pid == 0) { 5187 // child process 5188 5189 // execve() in LinuxThreads will call pthread_kill_other_threads_np() 5190 // first to kill every thread on the thread list. Because this list is 5191 // not reset by fork() (see notes above), execve() will instead kill 5192 // every thread in the parent process. We know this is the only thread 5193 // in the new process, so make a system call directly. 5194 // IA64 should use normal execve() from glibc to match the glibc fork() 5195 // above. 5196 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);) 5197 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);) 5198 5199 // execve failed 5200 _exit(-1); 5201 5202 } else { 5203 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5204 // care about the actual exit code, for now. 5205 5206 int status; 5207 5208 // Wait for the child process to exit. This returns immediately if 5209 // the child has already exited. */ 5210 while (waitpid(pid, &status, 0) < 0) { 5211 switch (errno) { 5212 case ECHILD: return 0; 5213 case EINTR: break; 5214 default: return -1; 5215 } 5216 } 5217 5218 if (WIFEXITED(status)) { 5219 // The child exited normally; get its exit code. 5220 return WEXITSTATUS(status); 5221 } else if (WIFSIGNALED(status)) { 5222 // The child exited because of a signal 5223 // The best value to return is 0x80 + signal number, 5224 // because that is what all Unix shells do, and because 5225 // it allows callers to distinguish between process exit and 5226 // process death by signal. 5227 return 0x80 + WTERMSIG(status); 5228 } else { 5229 // Unknown exit code; pass it through 5230 return status; 5231 } 5232 } 5233 } 5234 5235 // is_headless_jre() 5236 // 5237 // Test for the existence of libmawt in motif21 or xawt directories 5238 // in order to report if we are running in a headless jre 5239 // 5240 bool os::is_headless_jre() { 5241 struct stat statbuf; 5242 char buf[MAXPATHLEN]; 5243 char libmawtpath[MAXPATHLEN]; 5244 const char *xawtstr = "/xawt/libmawt.so"; 5245 const char *motifstr = "/motif21/libmawt.so"; 5246 char *p; 5247 5248 // Get path to libjvm.so 5249 os::jvm_path(buf, sizeof(buf)); 5250 5251 // Get rid of libjvm.so 5252 p = strrchr(buf, '/'); 5253 if (p == NULL) return false; 5254 else *p = '\0'; 5255 5256 // Get rid of client or server 5257 p = strrchr(buf, '/'); 5258 if (p == NULL) return false; 5259 else *p = '\0'; 5260 5261 // check xawt/libmawt.so 5262 strcpy(libmawtpath, buf); 5263 strcat(libmawtpath, xawtstr); 5264 if (::stat(libmawtpath, &statbuf) == 0) return false; 5265 5266 // check motif21/libmawt.so 5267 strcpy(libmawtpath, buf); 5268 strcat(libmawtpath, motifstr); 5269 if (::stat(libmawtpath, &statbuf) == 0) return false; 5270 5271 return true; 5272 } 5273