1/* 2 * Copyright (c) 1999, 2017, 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#include "utilities/globalDefinitions.hpp" 26#include "prims/jvm.h" 27#include "runtime/frame.inline.hpp" 28#include "runtime/interfaceSupport.hpp" 29#include "runtime/os.hpp" 30#include "utilities/align.hpp" 31#include "utilities/macros.hpp" 32#include "utilities/vmError.hpp" 33 34#ifndef __APPLE__ 35// POSIX unamed semaphores are not supported on OS X. 36#include "semaphore_posix.hpp" 37#endif 38 39#include <dlfcn.h> 40#include <pthread.h> 41#include <semaphore.h> 42#include <signal.h> 43#include <sys/resource.h> 44#include <sys/utsname.h> 45#include <time.h> 46#include <unistd.h> 47 48// Todo: provide a os::get_max_process_id() or similar. Number of processes 49// may have been configured, can be read more accurately from proc fs etc. 50#ifndef MAX_PID 51#define MAX_PID INT_MAX 52#endif 53#define IS_VALID_PID(p) (p > 0 && p < MAX_PID) 54 55// Check core dump limit and report possible place where core can be found 56void os::check_dump_limit(char* buffer, size_t bufferSize) { 57 if (!FLAG_IS_DEFAULT(CreateCoredumpOnCrash) && !CreateCoredumpOnCrash) { 58 jio_snprintf(buffer, bufferSize, "CreateCoredumpOnCrash is disabled from command line"); 59 VMError::record_coredump_status(buffer, false); 60 return; 61 } 62 63 int n; 64 struct rlimit rlim; 65 bool success; 66 67 char core_path[PATH_MAX]; 68 n = get_core_path(core_path, PATH_MAX); 69 70 if (n <= 0) { 71 jio_snprintf(buffer, bufferSize, "core.%d (may not exist)", current_process_id()); 72 success = true; 73#ifdef LINUX 74 } else if (core_path[0] == '"') { // redirect to user process 75 jio_snprintf(buffer, bufferSize, "Core dumps may be processed with %s", core_path); 76 success = true; 77#endif 78 } else if (getrlimit(RLIMIT_CORE, &rlim) != 0) { 79 jio_snprintf(buffer, bufferSize, "%s (may not exist)", core_path); 80 success = true; 81 } else { 82 switch(rlim.rlim_cur) { 83 case RLIM_INFINITY: 84 jio_snprintf(buffer, bufferSize, "%s", core_path); 85 success = true; 86 break; 87 case 0: 88 jio_snprintf(buffer, bufferSize, "Core dumps have been disabled. To enable core dumping, try \"ulimit -c unlimited\" before starting Java again"); 89 success = false; 90 break; 91 default: 92 jio_snprintf(buffer, bufferSize, "%s (max size " UINT64_FORMAT " kB). To ensure a full core dump, try \"ulimit -c unlimited\" before starting Java again", core_path, uint64_t(rlim.rlim_cur) / 1024); 93 success = true; 94 break; 95 } 96 } 97 98 VMError::record_coredump_status(buffer, success); 99} 100 101int os::get_native_stack(address* stack, int frames, int toSkip) { 102 int frame_idx = 0; 103 int num_of_frames; // number of frames captured 104 frame fr = os::current_frame(); 105 while (fr.pc() && frame_idx < frames) { 106 if (toSkip > 0) { 107 toSkip --; 108 } else { 109 stack[frame_idx ++] = fr.pc(); 110 } 111 if (fr.fp() == NULL || fr.cb() != NULL || 112 fr.sender_pc() == NULL || os::is_first_C_frame(&fr)) break; 113 114 if (fr.sender_pc() && !os::is_first_C_frame(&fr)) { 115 fr = os::get_sender_for_C_frame(&fr); 116 } else { 117 break; 118 } 119 } 120 num_of_frames = frame_idx; 121 for (; frame_idx < frames; frame_idx ++) { 122 stack[frame_idx] = NULL; 123 } 124 125 return num_of_frames; 126} 127 128 129bool os::unsetenv(const char* name) { 130 assert(name != NULL, "Null pointer"); 131 return (::unsetenv(name) == 0); 132} 133 134int os::get_last_error() { 135 return errno; 136} 137 138bool os::is_debugger_attached() { 139 // not implemented 140 return false; 141} 142 143void os::wait_for_keypress_at_exit(void) { 144 // don't do anything on posix platforms 145 return; 146} 147 148// Multiple threads can race in this code, and can remap over each other with MAP_FIXED, 149// so on posix, unmap the section at the start and at the end of the chunk that we mapped 150// rather than unmapping and remapping the whole chunk to get requested alignment. 151char* os::reserve_memory_aligned(size_t size, size_t alignment) { 152 assert((alignment & (os::vm_allocation_granularity() - 1)) == 0, 153 "Alignment must be a multiple of allocation granularity (page size)"); 154 assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned"); 155 156 size_t extra_size = size + alignment; 157 assert(extra_size >= size, "overflow, size is too large to allow alignment"); 158 159 char* extra_base = os::reserve_memory(extra_size, NULL, alignment); 160 161 if (extra_base == NULL) { 162 return NULL; 163 } 164 165 // Do manual alignment 166 char* aligned_base = align_up(extra_base, alignment); 167 168 // [ | | ] 169 // ^ extra_base 170 // ^ extra_base + begin_offset == aligned_base 171 // extra_base + begin_offset + size ^ 172 // extra_base + extra_size ^ 173 // |<>| == begin_offset 174 // end_offset == |<>| 175 size_t begin_offset = aligned_base - extra_base; 176 size_t end_offset = (extra_base + extra_size) - (aligned_base + size); 177 178 if (begin_offset > 0) { 179 os::release_memory(extra_base, begin_offset); 180 } 181 182 if (end_offset > 0) { 183 os::release_memory(extra_base + begin_offset + size, end_offset); 184 } 185 186 return aligned_base; 187} 188 189int os::log_vsnprintf(char* buf, size_t len, const char* fmt, va_list args) { 190 return vsnprintf(buf, len, fmt, args); 191} 192 193int os::get_fileno(FILE* fp) { 194 return NOT_AIX(::)fileno(fp); 195} 196 197struct tm* os::gmtime_pd(const time_t* clock, struct tm* res) { 198 return gmtime_r(clock, res); 199} 200 201void os::Posix::print_load_average(outputStream* st) { 202 st->print("load average:"); 203 double loadavg[3]; 204 os::loadavg(loadavg, 3); 205 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]); 206 st->cr(); 207} 208 209void os::Posix::print_rlimit_info(outputStream* st) { 210 st->print("rlimit:"); 211 struct rlimit rlim; 212 213 st->print(" STACK "); 214 getrlimit(RLIMIT_STACK, &rlim); 215 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 216 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); 217 218 st->print(", CORE "); 219 getrlimit(RLIMIT_CORE, &rlim); 220 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 221 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); 222 223 // Isn't there on solaris 224#if defined(AIX) 225 st->print(", NPROC "); 226 st->print("%d", sysconf(_SC_CHILD_MAX)); 227#elif !defined(SOLARIS) 228 st->print(", NPROC "); 229 getrlimit(RLIMIT_NPROC, &rlim); 230 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 231 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur)); 232#endif 233 234 st->print(", NOFILE "); 235 getrlimit(RLIMIT_NOFILE, &rlim); 236 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 237 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur)); 238 239 st->print(", AS "); 240 getrlimit(RLIMIT_AS, &rlim); 241 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 242 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); 243 244 st->print(", DATA "); 245 getrlimit(RLIMIT_DATA, &rlim); 246 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 247 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); 248 249 st->print(", FSIZE "); 250 getrlimit(RLIMIT_FSIZE, &rlim); 251 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 252 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); 253 254 st->cr(); 255} 256 257void os::Posix::print_uname_info(outputStream* st) { 258 // kernel 259 st->print("uname:"); 260 struct utsname name; 261 uname(&name); 262 st->print("%s ", name.sysname); 263#ifdef ASSERT 264 st->print("%s ", name.nodename); 265#endif 266 st->print("%s ", name.release); 267 st->print("%s ", name.version); 268 st->print("%s", name.machine); 269 st->cr(); 270} 271 272bool os::get_host_name(char* buf, size_t buflen) { 273 struct utsname name; 274 uname(&name); 275 jio_snprintf(buf, buflen, "%s", name.nodename); 276 return true; 277} 278 279bool os::has_allocatable_memory_limit(julong* limit) { 280 struct rlimit rlim; 281 int getrlimit_res = getrlimit(RLIMIT_AS, &rlim); 282 // if there was an error when calling getrlimit, assume that there is no limitation 283 // on virtual memory. 284 bool result; 285 if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) { 286 result = false; 287 } else { 288 *limit = (julong)rlim.rlim_cur; 289 result = true; 290 } 291#ifdef _LP64 292 return result; 293#else 294 // arbitrary virtual space limit for 32 bit Unices found by testing. If 295 // getrlimit above returned a limit, bound it with this limit. Otherwise 296 // directly use it. 297 const julong max_virtual_limit = (julong)3800*M; 298 if (result) { 299 *limit = MIN2(*limit, max_virtual_limit); 300 } else { 301 *limit = max_virtual_limit; 302 } 303 304 // bound by actually allocatable memory. The algorithm uses two bounds, an 305 // upper and a lower limit. The upper limit is the current highest amount of 306 // memory that could not be allocated, the lower limit is the current highest 307 // amount of memory that could be allocated. 308 // The algorithm iteratively refines the result by halving the difference 309 // between these limits, updating either the upper limit (if that value could 310 // not be allocated) or the lower limit (if the that value could be allocated) 311 // until the difference between these limits is "small". 312 313 // the minimum amount of memory we care about allocating. 314 const julong min_allocation_size = M; 315 316 julong upper_limit = *limit; 317 318 // first check a few trivial cases 319 if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) { 320 *limit = upper_limit; 321 } else if (!is_allocatable(min_allocation_size)) { 322 // we found that not even min_allocation_size is allocatable. Return it 323 // anyway. There is no point to search for a better value any more. 324 *limit = min_allocation_size; 325 } else { 326 // perform the binary search. 327 julong lower_limit = min_allocation_size; 328 while ((upper_limit - lower_limit) > min_allocation_size) { 329 julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit; 330 temp_limit = align_down(temp_limit, min_allocation_size); 331 if (is_allocatable(temp_limit)) { 332 lower_limit = temp_limit; 333 } else { 334 upper_limit = temp_limit; 335 } 336 } 337 *limit = lower_limit; 338 } 339 return true; 340#endif 341} 342 343const char* os::get_current_directory(char *buf, size_t buflen) { 344 return getcwd(buf, buflen); 345} 346 347FILE* os::open(int fd, const char* mode) { 348 return ::fdopen(fd, mode); 349} 350 351void os::flockfile(FILE* fp) { 352 ::flockfile(fp); 353} 354 355void os::funlockfile(FILE* fp) { 356 ::funlockfile(fp); 357} 358 359// Builds a platform dependent Agent_OnLoad_<lib_name> function name 360// which is used to find statically linked in agents. 361// Parameters: 362// sym_name: Symbol in library we are looking for 363// lib_name: Name of library to look in, NULL for shared libs. 364// is_absolute_path == true if lib_name is absolute path to agent 365// such as "/a/b/libL.so" 366// == false if only the base name of the library is passed in 367// such as "L" 368char* os::build_agent_function_name(const char *sym_name, const char *lib_name, 369 bool is_absolute_path) { 370 char *agent_entry_name; 371 size_t len; 372 size_t name_len; 373 size_t prefix_len = strlen(JNI_LIB_PREFIX); 374 size_t suffix_len = strlen(JNI_LIB_SUFFIX); 375 const char *start; 376 377 if (lib_name != NULL) { 378 name_len = strlen(lib_name); 379 if (is_absolute_path) { 380 // Need to strip path, prefix and suffix 381 if ((start = strrchr(lib_name, *os::file_separator())) != NULL) { 382 lib_name = ++start; 383 } 384 if (strlen(lib_name) <= (prefix_len + suffix_len)) { 385 return NULL; 386 } 387 lib_name += prefix_len; 388 name_len = strlen(lib_name) - suffix_len; 389 } 390 } 391 len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2; 392 agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread); 393 if (agent_entry_name == NULL) { 394 return NULL; 395 } 396 strcpy(agent_entry_name, sym_name); 397 if (lib_name != NULL) { 398 strcat(agent_entry_name, "_"); 399 strncat(agent_entry_name, lib_name, name_len); 400 } 401 return agent_entry_name; 402} 403 404int os::sleep(Thread* thread, jlong millis, bool interruptible) { 405 assert(thread == Thread::current(), "thread consistency check"); 406 407 ParkEvent * const slp = thread->_SleepEvent ; 408 slp->reset() ; 409 OrderAccess::fence() ; 410 411 if (interruptible) { 412 jlong prevtime = javaTimeNanos(); 413 414 for (;;) { 415 if (os::is_interrupted(thread, true)) { 416 return OS_INTRPT; 417 } 418 419 jlong newtime = javaTimeNanos(); 420 421 if (newtime - prevtime < 0) { 422 // time moving backwards, should only happen if no monotonic clock 423 // not a guarantee() because JVM should not abort on kernel/glibc bugs 424 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected in os::sleep(interruptible)"); 425 } else { 426 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 427 } 428 429 if (millis <= 0) { 430 return OS_OK; 431 } 432 433 prevtime = newtime; 434 435 { 436 assert(thread->is_Java_thread(), "sanity check"); 437 JavaThread *jt = (JavaThread *) thread; 438 ThreadBlockInVM tbivm(jt); 439 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 440 441 jt->set_suspend_equivalent(); 442 // cleared by handle_special_suspend_equivalent_condition() or 443 // java_suspend_self() via check_and_wait_while_suspended() 444 445 slp->park(millis); 446 447 // were we externally suspended while we were waiting? 448 jt->check_and_wait_while_suspended(); 449 } 450 } 451 } else { 452 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 453 jlong prevtime = javaTimeNanos(); 454 455 for (;;) { 456 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 457 // the 1st iteration ... 458 jlong newtime = javaTimeNanos(); 459 460 if (newtime - prevtime < 0) { 461 // time moving backwards, should only happen if no monotonic clock 462 // not a guarantee() because JVM should not abort on kernel/glibc bugs 463 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected on os::sleep(!interruptible)"); 464 } else { 465 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 466 } 467 468 if (millis <= 0) break ; 469 470 prevtime = newtime; 471 slp->park(millis); 472 } 473 return OS_OK ; 474 } 475} 476 477//////////////////////////////////////////////////////////////////////////////// 478// interrupt support 479 480void os::interrupt(Thread* thread) { 481 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 482 "possibility of dangling Thread pointer"); 483 484 OSThread* osthread = thread->osthread(); 485 486 if (!osthread->interrupted()) { 487 osthread->set_interrupted(true); 488 // More than one thread can get here with the same value of osthread, 489 // resulting in multiple notifications. We do, however, want the store 490 // to interrupted() to be visible to other threads before we execute unpark(). 491 OrderAccess::fence(); 492 ParkEvent * const slp = thread->_SleepEvent ; 493 if (slp != NULL) slp->unpark() ; 494 } 495 496 // For JSR166. Unpark even if interrupt status already was set 497 if (thread->is_Java_thread()) 498 ((JavaThread*)thread)->parker()->unpark(); 499 500 ParkEvent * ev = thread->_ParkEvent ; 501 if (ev != NULL) ev->unpark() ; 502 503} 504 505bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 506 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 507 "possibility of dangling Thread pointer"); 508 509 OSThread* osthread = thread->osthread(); 510 511 bool interrupted = osthread->interrupted(); 512 513 // NOTE that since there is no "lock" around the interrupt and 514 // is_interrupted operations, there is the possibility that the 515 // interrupted flag (in osThread) will be "false" but that the 516 // low-level events will be in the signaled state. This is 517 // intentional. The effect of this is that Object.wait() and 518 // LockSupport.park() will appear to have a spurious wakeup, which 519 // is allowed and not harmful, and the possibility is so rare that 520 // it is not worth the added complexity to add yet another lock. 521 // For the sleep event an explicit reset is performed on entry 522 // to os::sleep, so there is no early return. It has also been 523 // recommended not to put the interrupted flag into the "event" 524 // structure because it hides the issue. 525 if (interrupted && clear_interrupted) { 526 osthread->set_interrupted(false); 527 // consider thread->_SleepEvent->reset() ... optional optimization 528 } 529 530 return interrupted; 531} 532 533 534 535static const struct { 536 int sig; const char* name; 537} 538 g_signal_info[] = 539 { 540 { SIGABRT, "SIGABRT" }, 541#ifdef SIGAIO 542 { SIGAIO, "SIGAIO" }, 543#endif 544 { SIGALRM, "SIGALRM" }, 545#ifdef SIGALRM1 546 { SIGALRM1, "SIGALRM1" }, 547#endif 548 { SIGBUS, "SIGBUS" }, 549#ifdef SIGCANCEL 550 { SIGCANCEL, "SIGCANCEL" }, 551#endif 552 { SIGCHLD, "SIGCHLD" }, 553#ifdef SIGCLD 554 { SIGCLD, "SIGCLD" }, 555#endif 556 { SIGCONT, "SIGCONT" }, 557#ifdef SIGCPUFAIL 558 { SIGCPUFAIL, "SIGCPUFAIL" }, 559#endif 560#ifdef SIGDANGER 561 { SIGDANGER, "SIGDANGER" }, 562#endif 563#ifdef SIGDIL 564 { SIGDIL, "SIGDIL" }, 565#endif 566#ifdef SIGEMT 567 { SIGEMT, "SIGEMT" }, 568#endif 569 { SIGFPE, "SIGFPE" }, 570#ifdef SIGFREEZE 571 { SIGFREEZE, "SIGFREEZE" }, 572#endif 573#ifdef SIGGFAULT 574 { SIGGFAULT, "SIGGFAULT" }, 575#endif 576#ifdef SIGGRANT 577 { SIGGRANT, "SIGGRANT" }, 578#endif 579 { SIGHUP, "SIGHUP" }, 580 { SIGILL, "SIGILL" }, 581 { SIGINT, "SIGINT" }, 582#ifdef SIGIO 583 { SIGIO, "SIGIO" }, 584#endif 585#ifdef SIGIOINT 586 { SIGIOINT, "SIGIOINT" }, 587#endif 588#ifdef SIGIOT 589// SIGIOT is there for BSD compatibility, but on most Unices just a 590// synonym for SIGABRT. The result should be "SIGABRT", not 591// "SIGIOT". 592#if (SIGIOT != SIGABRT ) 593 { SIGIOT, "SIGIOT" }, 594#endif 595#endif 596#ifdef SIGKAP 597 { SIGKAP, "SIGKAP" }, 598#endif 599 { SIGKILL, "SIGKILL" }, 600#ifdef SIGLOST 601 { SIGLOST, "SIGLOST" }, 602#endif 603#ifdef SIGLWP 604 { SIGLWP, "SIGLWP" }, 605#endif 606#ifdef SIGLWPTIMER 607 { SIGLWPTIMER, "SIGLWPTIMER" }, 608#endif 609#ifdef SIGMIGRATE 610 { SIGMIGRATE, "SIGMIGRATE" }, 611#endif 612#ifdef SIGMSG 613 { SIGMSG, "SIGMSG" }, 614#endif 615 { SIGPIPE, "SIGPIPE" }, 616#ifdef SIGPOLL 617 { SIGPOLL, "SIGPOLL" }, 618#endif 619#ifdef SIGPRE 620 { SIGPRE, "SIGPRE" }, 621#endif 622 { SIGPROF, "SIGPROF" }, 623#ifdef SIGPTY 624 { SIGPTY, "SIGPTY" }, 625#endif 626#ifdef SIGPWR 627 { SIGPWR, "SIGPWR" }, 628#endif 629 { SIGQUIT, "SIGQUIT" }, 630#ifdef SIGRECONFIG 631 { SIGRECONFIG, "SIGRECONFIG" }, 632#endif 633#ifdef SIGRECOVERY 634 { SIGRECOVERY, "SIGRECOVERY" }, 635#endif 636#ifdef SIGRESERVE 637 { SIGRESERVE, "SIGRESERVE" }, 638#endif 639#ifdef SIGRETRACT 640 { SIGRETRACT, "SIGRETRACT" }, 641#endif 642#ifdef SIGSAK 643 { SIGSAK, "SIGSAK" }, 644#endif 645 { SIGSEGV, "SIGSEGV" }, 646#ifdef SIGSOUND 647 { SIGSOUND, "SIGSOUND" }, 648#endif 649#ifdef SIGSTKFLT 650 { SIGSTKFLT, "SIGSTKFLT" }, 651#endif 652 { SIGSTOP, "SIGSTOP" }, 653 { SIGSYS, "SIGSYS" }, 654#ifdef SIGSYSERROR 655 { SIGSYSERROR, "SIGSYSERROR" }, 656#endif 657#ifdef SIGTALRM 658 { SIGTALRM, "SIGTALRM" }, 659#endif 660 { SIGTERM, "SIGTERM" }, 661#ifdef SIGTHAW 662 { SIGTHAW, "SIGTHAW" }, 663#endif 664 { SIGTRAP, "SIGTRAP" }, 665#ifdef SIGTSTP 666 { SIGTSTP, "SIGTSTP" }, 667#endif 668 { SIGTTIN, "SIGTTIN" }, 669 { SIGTTOU, "SIGTTOU" }, 670#ifdef SIGURG 671 { SIGURG, "SIGURG" }, 672#endif 673 { SIGUSR1, "SIGUSR1" }, 674 { SIGUSR2, "SIGUSR2" }, 675#ifdef SIGVIRT 676 { SIGVIRT, "SIGVIRT" }, 677#endif 678 { SIGVTALRM, "SIGVTALRM" }, 679#ifdef SIGWAITING 680 { SIGWAITING, "SIGWAITING" }, 681#endif 682#ifdef SIGWINCH 683 { SIGWINCH, "SIGWINCH" }, 684#endif 685#ifdef SIGWINDOW 686 { SIGWINDOW, "SIGWINDOW" }, 687#endif 688 { SIGXCPU, "SIGXCPU" }, 689 { SIGXFSZ, "SIGXFSZ" }, 690#ifdef SIGXRES 691 { SIGXRES, "SIGXRES" }, 692#endif 693 { -1, NULL } 694}; 695 696// Returned string is a constant. For unknown signals "UNKNOWN" is returned. 697const char* os::Posix::get_signal_name(int sig, char* out, size_t outlen) { 698 699 const char* ret = NULL; 700 701#ifdef SIGRTMIN 702 if (sig >= SIGRTMIN && sig <= SIGRTMAX) { 703 if (sig == SIGRTMIN) { 704 ret = "SIGRTMIN"; 705 } else if (sig == SIGRTMAX) { 706 ret = "SIGRTMAX"; 707 } else { 708 jio_snprintf(out, outlen, "SIGRTMIN+%d", sig - SIGRTMIN); 709 return out; 710 } 711 } 712#endif 713 714 if (sig > 0) { 715 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) { 716 if (g_signal_info[idx].sig == sig) { 717 ret = g_signal_info[idx].name; 718 break; 719 } 720 } 721 } 722 723 if (!ret) { 724 if (!is_valid_signal(sig)) { 725 ret = "INVALID"; 726 } else { 727 ret = "UNKNOWN"; 728 } 729 } 730 731 if (out && outlen > 0) { 732 strncpy(out, ret, outlen); 733 out[outlen - 1] = '\0'; 734 } 735 return out; 736} 737 738int os::Posix::get_signal_number(const char* signal_name) { 739 char tmp[30]; 740 const char* s = signal_name; 741 if (s[0] != 'S' || s[1] != 'I' || s[2] != 'G') { 742 jio_snprintf(tmp, sizeof(tmp), "SIG%s", signal_name); 743 s = tmp; 744 } 745 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) { 746 if (strcmp(g_signal_info[idx].name, s) == 0) { 747 return g_signal_info[idx].sig; 748 } 749 } 750 return -1; 751} 752 753int os::get_signal_number(const char* signal_name) { 754 return os::Posix::get_signal_number(signal_name); 755} 756 757// Returns true if signal number is valid. 758bool os::Posix::is_valid_signal(int sig) { 759 // MacOS not really POSIX compliant: sigaddset does not return 760 // an error for invalid signal numbers. However, MacOS does not 761 // support real time signals and simply seems to have just 33 762 // signals with no holes in the signal range. 763#ifdef __APPLE__ 764 return sig >= 1 && sig < NSIG; 765#else 766 // Use sigaddset to check for signal validity. 767 sigset_t set; 768 sigemptyset(&set); 769 if (sigaddset(&set, sig) == -1 && errno == EINVAL) { 770 return false; 771 } 772 return true; 773#endif 774} 775 776// Returns: 777// NULL for an invalid signal number 778// "SIG<num>" for a valid but unknown signal number 779// signal name otherwise. 780const char* os::exception_name(int sig, char* buf, size_t size) { 781 if (!os::Posix::is_valid_signal(sig)) { 782 return NULL; 783 } 784 const char* const name = os::Posix::get_signal_name(sig, buf, size); 785 if (strcmp(name, "UNKNOWN") == 0) { 786 jio_snprintf(buf, size, "SIG%d", sig); 787 } 788 return buf; 789} 790 791#define NUM_IMPORTANT_SIGS 32 792// Returns one-line short description of a signal set in a user provided buffer. 793const char* os::Posix::describe_signal_set_short(const sigset_t* set, char* buffer, size_t buf_size) { 794 assert(buf_size == (NUM_IMPORTANT_SIGS + 1), "wrong buffer size"); 795 // Note: for shortness, just print out the first 32. That should 796 // cover most of the useful ones, apart from realtime signals. 797 for (int sig = 1; sig <= NUM_IMPORTANT_SIGS; sig++) { 798 const int rc = sigismember(set, sig); 799 if (rc == -1 && errno == EINVAL) { 800 buffer[sig-1] = '?'; 801 } else { 802 buffer[sig-1] = rc == 0 ? '0' : '1'; 803 } 804 } 805 buffer[NUM_IMPORTANT_SIGS] = 0; 806 return buffer; 807} 808 809// Prints one-line description of a signal set. 810void os::Posix::print_signal_set_short(outputStream* st, const sigset_t* set) { 811 char buf[NUM_IMPORTANT_SIGS + 1]; 812 os::Posix::describe_signal_set_short(set, buf, sizeof(buf)); 813 st->print("%s", buf); 814} 815 816// Writes one-line description of a combination of sigaction.sa_flags into a user 817// provided buffer. Returns that buffer. 818const char* os::Posix::describe_sa_flags(int flags, char* buffer, size_t size) { 819 char* p = buffer; 820 size_t remaining = size; 821 bool first = true; 822 int idx = 0; 823 824 assert(buffer, "invalid argument"); 825 826 if (size == 0) { 827 return buffer; 828 } 829 830 strncpy(buffer, "none", size); 831 832 const struct { 833 // NB: i is an unsigned int here because SA_RESETHAND is on some 834 // systems 0x80000000, which is implicitly unsigned. Assignining 835 // it to an int field would be an overflow in unsigned-to-signed 836 // conversion. 837 unsigned int i; 838 const char* s; 839 } flaginfo [] = { 840 { SA_NOCLDSTOP, "SA_NOCLDSTOP" }, 841 { SA_ONSTACK, "SA_ONSTACK" }, 842 { SA_RESETHAND, "SA_RESETHAND" }, 843 { SA_RESTART, "SA_RESTART" }, 844 { SA_SIGINFO, "SA_SIGINFO" }, 845 { SA_NOCLDWAIT, "SA_NOCLDWAIT" }, 846 { SA_NODEFER, "SA_NODEFER" }, 847#ifdef AIX 848 { SA_ONSTACK, "SA_ONSTACK" }, 849 { SA_OLDSTYLE, "SA_OLDSTYLE" }, 850#endif 851 { 0, NULL } 852 }; 853 854 for (idx = 0; flaginfo[idx].s && remaining > 1; idx++) { 855 if (flags & flaginfo[idx].i) { 856 if (first) { 857 jio_snprintf(p, remaining, "%s", flaginfo[idx].s); 858 first = false; 859 } else { 860 jio_snprintf(p, remaining, "|%s", flaginfo[idx].s); 861 } 862 const size_t len = strlen(p); 863 p += len; 864 remaining -= len; 865 } 866 } 867 868 buffer[size - 1] = '\0'; 869 870 return buffer; 871} 872 873// Prints one-line description of a combination of sigaction.sa_flags. 874void os::Posix::print_sa_flags(outputStream* st, int flags) { 875 char buffer[0x100]; 876 os::Posix::describe_sa_flags(flags, buffer, sizeof(buffer)); 877 st->print("%s", buffer); 878} 879 880// Helper function for os::Posix::print_siginfo_...(): 881// return a textual description for signal code. 882struct enum_sigcode_desc_t { 883 const char* s_name; 884 const char* s_desc; 885}; 886 887static bool get_signal_code_description(const siginfo_t* si, enum_sigcode_desc_t* out) { 888 889 const struct { 890 int sig; int code; const char* s_code; const char* s_desc; 891 } t1 [] = { 892 { SIGILL, ILL_ILLOPC, "ILL_ILLOPC", "Illegal opcode." }, 893 { SIGILL, ILL_ILLOPN, "ILL_ILLOPN", "Illegal operand." }, 894 { SIGILL, ILL_ILLADR, "ILL_ILLADR", "Illegal addressing mode." }, 895 { SIGILL, ILL_ILLTRP, "ILL_ILLTRP", "Illegal trap." }, 896 { SIGILL, ILL_PRVOPC, "ILL_PRVOPC", "Privileged opcode." }, 897 { SIGILL, ILL_PRVREG, "ILL_PRVREG", "Privileged register." }, 898 { SIGILL, ILL_COPROC, "ILL_COPROC", "Coprocessor error." }, 899 { SIGILL, ILL_BADSTK, "ILL_BADSTK", "Internal stack error." }, 900#if defined(IA64) && defined(LINUX) 901 { SIGILL, ILL_BADIADDR, "ILL_BADIADDR", "Unimplemented instruction address" }, 902 { SIGILL, ILL_BREAK, "ILL_BREAK", "Application Break instruction" }, 903#endif 904 { SIGFPE, FPE_INTDIV, "FPE_INTDIV", "Integer divide by zero." }, 905 { SIGFPE, FPE_INTOVF, "FPE_INTOVF", "Integer overflow." }, 906 { SIGFPE, FPE_FLTDIV, "FPE_FLTDIV", "Floating-point divide by zero." }, 907 { SIGFPE, FPE_FLTOVF, "FPE_FLTOVF", "Floating-point overflow." }, 908 { SIGFPE, FPE_FLTUND, "FPE_FLTUND", "Floating-point underflow." }, 909 { SIGFPE, FPE_FLTRES, "FPE_FLTRES", "Floating-point inexact result." }, 910 { SIGFPE, FPE_FLTINV, "FPE_FLTINV", "Invalid floating-point operation." }, 911 { SIGFPE, FPE_FLTSUB, "FPE_FLTSUB", "Subscript out of range." }, 912 { SIGSEGV, SEGV_MAPERR, "SEGV_MAPERR", "Address not mapped to object." }, 913 { SIGSEGV, SEGV_ACCERR, "SEGV_ACCERR", "Invalid permissions for mapped object." }, 914#ifdef AIX 915 // no explanation found what keyerr would be 916 { SIGSEGV, SEGV_KEYERR, "SEGV_KEYERR", "key error" }, 917#endif 918#if defined(IA64) && !defined(AIX) 919 { SIGSEGV, SEGV_PSTKOVF, "SEGV_PSTKOVF", "Paragraph stack overflow" }, 920#endif 921#if defined(__sparc) && defined(SOLARIS) 922// define Solaris Sparc M7 ADI SEGV signals 923#if !defined(SEGV_ACCADI) 924#define SEGV_ACCADI 3 925#endif 926 { SIGSEGV, SEGV_ACCADI, "SEGV_ACCADI", "ADI not enabled for mapped object." }, 927#if !defined(SEGV_ACCDERR) 928#define SEGV_ACCDERR 4 929#endif 930 { SIGSEGV, SEGV_ACCDERR, "SEGV_ACCDERR", "ADI disrupting exception." }, 931#if !defined(SEGV_ACCPERR) 932#define SEGV_ACCPERR 5 933#endif 934 { SIGSEGV, SEGV_ACCPERR, "SEGV_ACCPERR", "ADI precise exception." }, 935#endif // defined(__sparc) && defined(SOLARIS) 936 { SIGBUS, BUS_ADRALN, "BUS_ADRALN", "Invalid address alignment." }, 937 { SIGBUS, BUS_ADRERR, "BUS_ADRERR", "Nonexistent physical address." }, 938 { SIGBUS, BUS_OBJERR, "BUS_OBJERR", "Object-specific hardware error." }, 939 { SIGTRAP, TRAP_BRKPT, "TRAP_BRKPT", "Process breakpoint." }, 940 { SIGTRAP, TRAP_TRACE, "TRAP_TRACE", "Process trace trap." }, 941 { SIGCHLD, CLD_EXITED, "CLD_EXITED", "Child has exited." }, 942 { SIGCHLD, CLD_KILLED, "CLD_KILLED", "Child has terminated abnormally and did not create a core file." }, 943 { SIGCHLD, CLD_DUMPED, "CLD_DUMPED", "Child has terminated abnormally and created a core file." }, 944 { SIGCHLD, CLD_TRAPPED, "CLD_TRAPPED", "Traced child has trapped." }, 945 { SIGCHLD, CLD_STOPPED, "CLD_STOPPED", "Child has stopped." }, 946 { SIGCHLD, CLD_CONTINUED,"CLD_CONTINUED","Stopped child has continued." }, 947#ifdef SIGPOLL 948 { SIGPOLL, POLL_OUT, "POLL_OUT", "Output buffers available." }, 949 { SIGPOLL, POLL_MSG, "POLL_MSG", "Input message available." }, 950 { SIGPOLL, POLL_ERR, "POLL_ERR", "I/O error." }, 951 { SIGPOLL, POLL_PRI, "POLL_PRI", "High priority input available." }, 952 { SIGPOLL, POLL_HUP, "POLL_HUP", "Device disconnected. [Option End]" }, 953#endif 954 { -1, -1, NULL, NULL } 955 }; 956 957 // Codes valid in any signal context. 958 const struct { 959 int code; const char* s_code; const char* s_desc; 960 } t2 [] = { 961 { SI_USER, "SI_USER", "Signal sent by kill()." }, 962 { SI_QUEUE, "SI_QUEUE", "Signal sent by the sigqueue()." }, 963 { SI_TIMER, "SI_TIMER", "Signal generated by expiration of a timer set by timer_settime()." }, 964 { SI_ASYNCIO, "SI_ASYNCIO", "Signal generated by completion of an asynchronous I/O request." }, 965 { SI_MESGQ, "SI_MESGQ", "Signal generated by arrival of a message on an empty message queue." }, 966 // Linux specific 967#ifdef SI_TKILL 968 { SI_TKILL, "SI_TKILL", "Signal sent by tkill (pthread_kill)" }, 969#endif 970#ifdef SI_DETHREAD 971 { SI_DETHREAD, "SI_DETHREAD", "Signal sent by execve() killing subsidiary threads" }, 972#endif 973#ifdef SI_KERNEL 974 { SI_KERNEL, "SI_KERNEL", "Signal sent by kernel." }, 975#endif 976#ifdef SI_SIGIO 977 { SI_SIGIO, "SI_SIGIO", "Signal sent by queued SIGIO" }, 978#endif 979 980#ifdef AIX 981 { SI_UNDEFINED, "SI_UNDEFINED","siginfo contains partial information" }, 982 { SI_EMPTY, "SI_EMPTY", "siginfo contains no useful information" }, 983#endif 984 985#ifdef __sun 986 { SI_NOINFO, "SI_NOINFO", "No signal information" }, 987 { SI_RCTL, "SI_RCTL", "kernel generated signal via rctl action" }, 988 { SI_LWP, "SI_LWP", "Signal sent via lwp_kill" }, 989#endif 990 991 { -1, NULL, NULL } 992 }; 993 994 const char* s_code = NULL; 995 const char* s_desc = NULL; 996 997 for (int i = 0; t1[i].sig != -1; i ++) { 998 if (t1[i].sig == si->si_signo && t1[i].code == si->si_code) { 999 s_code = t1[i].s_code; 1000 s_desc = t1[i].s_desc; 1001 break; 1002 } 1003 } 1004 1005 if (s_code == NULL) { 1006 for (int i = 0; t2[i].s_code != NULL; i ++) { 1007 if (t2[i].code == si->si_code) { 1008 s_code = t2[i].s_code; 1009 s_desc = t2[i].s_desc; 1010 } 1011 } 1012 } 1013 1014 if (s_code == NULL) { 1015 out->s_name = "unknown"; 1016 out->s_desc = "unknown"; 1017 return false; 1018 } 1019 1020 out->s_name = s_code; 1021 out->s_desc = s_desc; 1022 1023 return true; 1024} 1025 1026void os::print_siginfo(outputStream* os, const void* si0) { 1027 1028 const siginfo_t* const si = (const siginfo_t*) si0; 1029 1030 char buf[20]; 1031 os->print("siginfo:"); 1032 1033 if (!si) { 1034 os->print(" <null>"); 1035 return; 1036 } 1037 1038 const int sig = si->si_signo; 1039 1040 os->print(" si_signo: %d (%s)", sig, os::Posix::get_signal_name(sig, buf, sizeof(buf))); 1041 1042 enum_sigcode_desc_t ed; 1043 get_signal_code_description(si, &ed); 1044 os->print(", si_code: %d (%s)", si->si_code, ed.s_name); 1045 1046 if (si->si_errno) { 1047 os->print(", si_errno: %d", si->si_errno); 1048 } 1049 1050 // Output additional information depending on the signal code. 1051 1052 // Note: Many implementations lump si_addr, si_pid, si_uid etc. together as unions, 1053 // so it depends on the context which member to use. For synchronous error signals, 1054 // we print si_addr, unless the signal was sent by another process or thread, in 1055 // which case we print out pid or tid of the sender. 1056 if (si->si_code == SI_USER || si->si_code == SI_QUEUE) { 1057 const pid_t pid = si->si_pid; 1058 os->print(", si_pid: %ld", (long) pid); 1059 if (IS_VALID_PID(pid)) { 1060 const pid_t me = getpid(); 1061 if (me == pid) { 1062 os->print(" (current process)"); 1063 } 1064 } else { 1065 os->print(" (invalid)"); 1066 } 1067 os->print(", si_uid: %ld", (long) si->si_uid); 1068 if (sig == SIGCHLD) { 1069 os->print(", si_status: %d", si->si_status); 1070 } 1071 } else if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL || 1072 sig == SIGTRAP || sig == SIGFPE) { 1073 os->print(", si_addr: " PTR_FORMAT, p2i(si->si_addr)); 1074#ifdef SIGPOLL 1075 } else if (sig == SIGPOLL) { 1076 os->print(", si_band: %ld", si->si_band); 1077#endif 1078 } 1079 1080} 1081 1082int os::Posix::unblock_thread_signal_mask(const sigset_t *set) { 1083 return pthread_sigmask(SIG_UNBLOCK, set, NULL); 1084} 1085 1086address os::Posix::ucontext_get_pc(const ucontext_t* ctx) { 1087#if defined(AIX) 1088 return Aix::ucontext_get_pc(ctx); 1089#elif defined(BSD) 1090 return Bsd::ucontext_get_pc(ctx); 1091#elif defined(LINUX) 1092 return Linux::ucontext_get_pc(ctx); 1093#elif defined(SOLARIS) 1094 return Solaris::ucontext_get_pc(ctx); 1095#else 1096 VMError::report_and_die("unimplemented ucontext_get_pc"); 1097#endif 1098} 1099 1100void os::Posix::ucontext_set_pc(ucontext_t* ctx, address pc) { 1101#if defined(AIX) 1102 Aix::ucontext_set_pc(ctx, pc); 1103#elif defined(BSD) 1104 Bsd::ucontext_set_pc(ctx, pc); 1105#elif defined(LINUX) 1106 Linux::ucontext_set_pc(ctx, pc); 1107#elif defined(SOLARIS) 1108 Solaris::ucontext_set_pc(ctx, pc); 1109#else 1110 VMError::report_and_die("unimplemented ucontext_get_pc"); 1111#endif 1112} 1113 1114char* os::Posix::describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr) { 1115 size_t stack_size = 0; 1116 size_t guard_size = 0; 1117 int detachstate = 0; 1118 pthread_attr_getstacksize(attr, &stack_size); 1119 pthread_attr_getguardsize(attr, &guard_size); 1120 // Work around linux NPTL implementation error, see also os::create_thread() in os_linux.cpp. 1121 LINUX_ONLY(stack_size -= guard_size); 1122 pthread_attr_getdetachstate(attr, &detachstate); 1123 jio_snprintf(buf, buflen, "stacksize: " SIZE_FORMAT "k, guardsize: " SIZE_FORMAT "k, %s", 1124 stack_size / 1024, guard_size / 1024, 1125 (detachstate == PTHREAD_CREATE_DETACHED ? "detached" : "joinable")); 1126 return buf; 1127} 1128 1129char* os::Posix::realpath(const char* filename, char* outbuf, size_t outbuflen) { 1130 1131 if (filename == NULL || outbuf == NULL || outbuflen < 1) { 1132 assert(false, "os::Posix::realpath: invalid arguments."); 1133 errno = EINVAL; 1134 return NULL; 1135 } 1136 1137 char* result = NULL; 1138 1139 // This assumes platform realpath() is implemented according to POSIX.1-2008. 1140 // POSIX.1-2008 allows to specify NULL for the output buffer, in which case 1141 // output buffer is dynamically allocated and must be ::free()'d by the caller. 1142 char* p = ::realpath(filename, NULL); 1143 if (p != NULL) { 1144 if (strlen(p) < outbuflen) { 1145 strcpy(outbuf, p); 1146 result = outbuf; 1147 } else { 1148 errno = ENAMETOOLONG; 1149 } 1150 ::free(p); // *not* os::free 1151 } else { 1152 // Fallback for platforms struggling with modern Posix standards (AIX 5.3, 6.1). If realpath 1153 // returns EINVAL, this may indicate that realpath is not POSIX.1-2008 compatible and 1154 // that it complains about the NULL we handed down as user buffer. 1155 // In this case, use the user provided buffer but at least check whether realpath caused 1156 // a memory overwrite. 1157 if (errno == EINVAL) { 1158 outbuf[outbuflen - 1] = '\0'; 1159 p = ::realpath(filename, outbuf); 1160 if (p != NULL) { 1161 guarantee(outbuf[outbuflen - 1] == '\0', "realpath buffer overwrite detected."); 1162 result = p; 1163 } 1164 } 1165 } 1166 return result; 1167 1168} 1169 1170 1171// Check minimum allowable stack sizes for thread creation and to initialize 1172// the java system classes, including StackOverflowError - depends on page 1173// size. 1174// The space needed for frames during startup is platform dependent. It 1175// depends on word size, platform calling conventions, C frame layout and 1176// interpreter/C1/C2 design decisions. Therefore this is given in a 1177// platform (os/cpu) dependent constant. 1178// To this, space for guard mechanisms is added, which depends on the 1179// page size which again depends on the concrete system the VM is running 1180// on. Space for libc guard pages is not included in this size. 1181jint os::Posix::set_minimum_stack_sizes() { 1182 size_t os_min_stack_allowed = SOLARIS_ONLY(thr_min_stack()) NOT_SOLARIS(PTHREAD_STACK_MIN); 1183 1184 _java_thread_min_stack_allowed = _java_thread_min_stack_allowed + 1185 JavaThread::stack_guard_zone_size() + 1186 JavaThread::stack_shadow_zone_size(); 1187 1188 _java_thread_min_stack_allowed = align_up(_java_thread_min_stack_allowed, vm_page_size()); 1189 _java_thread_min_stack_allowed = MAX2(_java_thread_min_stack_allowed, os_min_stack_allowed); 1190 1191 size_t stack_size_in_bytes = ThreadStackSize * K; 1192 if (stack_size_in_bytes != 0 && 1193 stack_size_in_bytes < _java_thread_min_stack_allowed) { 1194 // The '-Xss' and '-XX:ThreadStackSize=N' options both set 1195 // ThreadStackSize so we go with "Java thread stack size" instead 1196 // of "ThreadStackSize" to be more friendly. 1197 tty->print_cr("\nThe Java thread stack size specified is too small. " 1198 "Specify at least " SIZE_FORMAT "k", 1199 _java_thread_min_stack_allowed / K); 1200 return JNI_ERR; 1201 } 1202 1203 // Make the stack size a multiple of the page size so that 1204 // the yellow/red zones can be guarded. 1205 JavaThread::set_stack_size_at_create(align_up(stack_size_in_bytes, vm_page_size())); 1206 1207 // Reminder: a compiler thread is a Java thread. 1208 _compiler_thread_min_stack_allowed = _compiler_thread_min_stack_allowed + 1209 JavaThread::stack_guard_zone_size() + 1210 JavaThread::stack_shadow_zone_size(); 1211 1212 _compiler_thread_min_stack_allowed = align_up(_compiler_thread_min_stack_allowed, vm_page_size()); 1213 _compiler_thread_min_stack_allowed = MAX2(_compiler_thread_min_stack_allowed, os_min_stack_allowed); 1214 1215 stack_size_in_bytes = CompilerThreadStackSize * K; 1216 if (stack_size_in_bytes != 0 && 1217 stack_size_in_bytes < _compiler_thread_min_stack_allowed) { 1218 tty->print_cr("\nThe CompilerThreadStackSize specified is too small. " 1219 "Specify at least " SIZE_FORMAT "k", 1220 _compiler_thread_min_stack_allowed / K); 1221 return JNI_ERR; 1222 } 1223 1224 _vm_internal_thread_min_stack_allowed = align_up(_vm_internal_thread_min_stack_allowed, vm_page_size()); 1225 _vm_internal_thread_min_stack_allowed = MAX2(_vm_internal_thread_min_stack_allowed, os_min_stack_allowed); 1226 1227 stack_size_in_bytes = VMThreadStackSize * K; 1228 if (stack_size_in_bytes != 0 && 1229 stack_size_in_bytes < _vm_internal_thread_min_stack_allowed) { 1230 tty->print_cr("\nThe VMThreadStackSize specified is too small. " 1231 "Specify at least " SIZE_FORMAT "k", 1232 _vm_internal_thread_min_stack_allowed / K); 1233 return JNI_ERR; 1234 } 1235 return JNI_OK; 1236} 1237 1238// Called when creating the thread. The minimum stack sizes have already been calculated 1239size_t os::Posix::get_initial_stack_size(ThreadType thr_type, size_t req_stack_size) { 1240 size_t stack_size; 1241 if (req_stack_size == 0) { 1242 stack_size = default_stack_size(thr_type); 1243 } else { 1244 stack_size = req_stack_size; 1245 } 1246 1247 switch (thr_type) { 1248 case os::java_thread: 1249 // Java threads use ThreadStackSize which default value can be 1250 // changed with the flag -Xss 1251 if (req_stack_size == 0 && JavaThread::stack_size_at_create() > 0) { 1252 // no requested size and we have a more specific default value 1253 stack_size = JavaThread::stack_size_at_create(); 1254 } 1255 stack_size = MAX2(stack_size, 1256 _java_thread_min_stack_allowed); 1257 break; 1258 case os::compiler_thread: 1259 if (req_stack_size == 0 && CompilerThreadStackSize > 0) { 1260 // no requested size and we have a more specific default value 1261 stack_size = (size_t)(CompilerThreadStackSize * K); 1262 } 1263 stack_size = MAX2(stack_size, 1264 _compiler_thread_min_stack_allowed); 1265 break; 1266 case os::vm_thread: 1267 case os::pgc_thread: 1268 case os::cgc_thread: 1269 case os::watcher_thread: 1270 default: // presume the unknown thr_type is a VM internal 1271 if (req_stack_size == 0 && VMThreadStackSize > 0) { 1272 // no requested size and we have a more specific default value 1273 stack_size = (size_t)(VMThreadStackSize * K); 1274 } 1275 1276 stack_size = MAX2(stack_size, 1277 _vm_internal_thread_min_stack_allowed); 1278 break; 1279 } 1280 1281 // pthread_attr_setstacksize() may require that the size be rounded up to the OS page size. 1282 // Be careful not to round up to 0. Align down in that case. 1283 if (stack_size <= SIZE_MAX - vm_page_size()) { 1284 stack_size = align_up(stack_size, vm_page_size()); 1285 } else { 1286 stack_size = align_down(stack_size, vm_page_size()); 1287 } 1288 1289 return stack_size; 1290} 1291 1292Thread* os::ThreadCrashProtection::_protected_thread = NULL; 1293os::ThreadCrashProtection* os::ThreadCrashProtection::_crash_protection = NULL; 1294volatile intptr_t os::ThreadCrashProtection::_crash_mux = 0; 1295 1296os::ThreadCrashProtection::ThreadCrashProtection() { 1297} 1298 1299/* 1300 * See the caveats for this class in os_posix.hpp 1301 * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this 1302 * method and returns false. If none of the signals are raised, returns true. 1303 * The callback is supposed to provide the method that should be protected. 1304 */ 1305bool os::ThreadCrashProtection::call(os::CrashProtectionCallback& cb) { 1306 sigset_t saved_sig_mask; 1307 1308 Thread::muxAcquire(&_crash_mux, "CrashProtection"); 1309 1310 _protected_thread = Thread::current_or_null(); 1311 assert(_protected_thread != NULL, "Cannot crash protect a NULL thread"); 1312 1313 // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask 1314 // since on at least some systems (OS X) siglongjmp will restore the mask 1315 // for the process, not the thread 1316 pthread_sigmask(0, NULL, &saved_sig_mask); 1317 if (sigsetjmp(_jmpbuf, 0) == 0) { 1318 // make sure we can see in the signal handler that we have crash protection 1319 // installed 1320 _crash_protection = this; 1321 cb.call(); 1322 // and clear the crash protection 1323 _crash_protection = NULL; 1324 _protected_thread = NULL; 1325 Thread::muxRelease(&_crash_mux); 1326 return true; 1327 } 1328 // this happens when we siglongjmp() back 1329 pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL); 1330 _crash_protection = NULL; 1331 _protected_thread = NULL; 1332 Thread::muxRelease(&_crash_mux); 1333 return false; 1334} 1335 1336void os::ThreadCrashProtection::restore() { 1337 assert(_crash_protection != NULL, "must have crash protection"); 1338 siglongjmp(_jmpbuf, 1); 1339} 1340 1341void os::ThreadCrashProtection::check_crash_protection(int sig, 1342 Thread* thread) { 1343 1344 if (thread != NULL && 1345 thread == _protected_thread && 1346 _crash_protection != NULL) { 1347 1348 if (sig == SIGSEGV || sig == SIGBUS) { 1349 _crash_protection->restore(); 1350 } 1351 } 1352} 1353 1354#define check_with_errno(check_type, cond, msg) \ 1355 do { \ 1356 int err = errno; \ 1357 check_type(cond, "%s; error='%s' (errno=%s)", msg, os::strerror(err), \ 1358 os::errno_name(err)); \ 1359} while (false) 1360 1361#define assert_with_errno(cond, msg) check_with_errno(assert, cond, msg) 1362#define guarantee_with_errno(cond, msg) check_with_errno(guarantee, cond, msg) 1363 1364// POSIX unamed semaphores are not supported on OS X. 1365#ifndef __APPLE__ 1366 1367PosixSemaphore::PosixSemaphore(uint value) { 1368 int ret = sem_init(&_semaphore, 0, value); 1369 1370 guarantee_with_errno(ret == 0, "Failed to initialize semaphore"); 1371} 1372 1373PosixSemaphore::~PosixSemaphore() { 1374 sem_destroy(&_semaphore); 1375} 1376 1377void PosixSemaphore::signal(uint count) { 1378 for (uint i = 0; i < count; i++) { 1379 int ret = sem_post(&_semaphore); 1380 1381 assert_with_errno(ret == 0, "sem_post failed"); 1382 } 1383} 1384 1385void PosixSemaphore::wait() { 1386 int ret; 1387 1388 do { 1389 ret = sem_wait(&_semaphore); 1390 } while (ret != 0 && errno == EINTR); 1391 1392 assert_with_errno(ret == 0, "sem_wait failed"); 1393} 1394 1395bool PosixSemaphore::trywait() { 1396 int ret; 1397 1398 do { 1399 ret = sem_trywait(&_semaphore); 1400 } while (ret != 0 && errno == EINTR); 1401 1402 assert_with_errno(ret == 0 || errno == EAGAIN, "trywait failed"); 1403 1404 return ret == 0; 1405} 1406 1407bool PosixSemaphore::timedwait(struct timespec ts) { 1408 while (true) { 1409 int result = sem_timedwait(&_semaphore, &ts); 1410 if (result == 0) { 1411 return true; 1412 } else if (errno == EINTR) { 1413 continue; 1414 } else if (errno == ETIMEDOUT) { 1415 return false; 1416 } else { 1417 assert_with_errno(false, "timedwait failed"); 1418 return false; 1419 } 1420 } 1421} 1422 1423#endif // __APPLE__ 1424 1425 1426// Shared pthread_mutex/cond based PlatformEvent implementation. 1427// Not currently usable by Solaris. 1428 1429#ifndef SOLARIS 1430 1431// Shared condattr object for use with relative timed-waits. Will be associated 1432// with CLOCK_MONOTONIC if available to avoid issues with time-of-day changes, 1433// but otherwise whatever default is used by the platform - generally the 1434// time-of-day clock. 1435static pthread_condattr_t _condAttr[1]; 1436 1437// Shared mutexattr to explicitly set the type to PTHREAD_MUTEX_NORMAL as not 1438// all systems (e.g. FreeBSD) map the default to "normal". 1439static pthread_mutexattr_t _mutexAttr[1]; 1440 1441// common basic initialization that is always supported 1442static void pthread_init_common(void) { 1443 int status; 1444 if ((status = pthread_condattr_init(_condAttr)) != 0) { 1445 fatal("pthread_condattr_init: %s", os::strerror(status)); 1446 } 1447 if ((status = pthread_mutexattr_init(_mutexAttr)) != 0) { 1448 fatal("pthread_mutexattr_init: %s", os::strerror(status)); 1449 } 1450 if ((status = pthread_mutexattr_settype(_mutexAttr, PTHREAD_MUTEX_NORMAL)) != 0) { 1451 fatal("pthread_mutexattr_settype: %s", os::strerror(status)); 1452 } 1453} 1454 1455// Not all POSIX types and API's are available on all notionally "posix" 1456// platforms. If we have build-time support then we will check for actual 1457// runtime support via dlopen/dlsym lookup. This allows for running on an 1458// older OS version compared to the build platform. But if there is no 1459// build time support then there cannot be any runtime support as we do not 1460// know what the runtime types would be (for example clockid_t might be an 1461// int or int64_t). 1462// 1463#ifdef SUPPORTS_CLOCK_MONOTONIC 1464 1465// This means we have clockid_t, clock_gettime et al and CLOCK_MONOTONIC 1466 1467static int (*_clock_gettime)(clockid_t, struct timespec *); 1468static int (*_pthread_condattr_setclock)(pthread_condattr_t *, clockid_t); 1469 1470static bool _use_clock_monotonic_condattr; 1471 1472// Determine what POSIX API's are present and do appropriate 1473// configuration. 1474void os::Posix::init(void) { 1475 1476 // NOTE: no logging available when this is called. Put logging 1477 // statements in init_2(). 1478 1479 // Copied from os::Linux::clock_init(). The duplication is temporary. 1480 1481 // 1. Check for CLOCK_MONOTONIC support. 1482 1483 void* handle = NULL; 1484 1485 // For linux we need librt, for other OS we can find 1486 // this function in regular libc. 1487#ifdef NEEDS_LIBRT 1488 // We do dlopen's in this particular order due to bug in linux 1489 // dynamic loader (see 6348968) leading to crash on exit. 1490 handle = dlopen("librt.so.1", RTLD_LAZY); 1491 if (handle == NULL) { 1492 handle = dlopen("librt.so", RTLD_LAZY); 1493 } 1494#endif 1495 1496 if (handle == NULL) { 1497 handle = RTLD_DEFAULT; 1498 } 1499 1500 _clock_gettime = NULL; 1501 1502 int (*clock_getres_func)(clockid_t, struct timespec*) = 1503 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1504 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1505 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1506 if (clock_getres_func != NULL && clock_gettime_func != NULL) { 1507 // We assume that if both clock_gettime and clock_getres support 1508 // CLOCK_MONOTONIC then the OS provides true high-res monotonic clock. 1509 struct timespec res; 1510 struct timespec tp; 1511 if (clock_getres_func(CLOCK_MONOTONIC, &res) == 0 && 1512 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1513 // Yes, monotonic clock is supported. 1514 _clock_gettime = clock_gettime_func; 1515 } else { 1516#ifdef NEEDS_LIBRT 1517 // Close librt if there is no monotonic clock. 1518 if (handle != RTLD_DEFAULT) { 1519 dlclose(handle); 1520 } 1521#endif 1522 } 1523 } 1524 1525 // 2. Check for pthread_condattr_setclock support. 1526 1527 _pthread_condattr_setclock = NULL; 1528 1529 // libpthread is already loaded. 1530 int (*condattr_setclock_func)(pthread_condattr_t*, clockid_t) = 1531 (int (*)(pthread_condattr_t*, clockid_t))dlsym(RTLD_DEFAULT, 1532 "pthread_condattr_setclock"); 1533 if (condattr_setclock_func != NULL) { 1534 _pthread_condattr_setclock = condattr_setclock_func; 1535 } 1536 1537 // Now do general initialization. 1538 1539 pthread_init_common(); 1540 1541 int status; 1542 if (_pthread_condattr_setclock != NULL && _clock_gettime != NULL) { 1543 if ((status = _pthread_condattr_setclock(_condAttr, CLOCK_MONOTONIC)) != 0) { 1544 if (status == EINVAL) { 1545 _use_clock_monotonic_condattr = false; 1546 warning("Unable to use monotonic clock with relative timed-waits" \ 1547 " - changes to the time-of-day clock may have adverse affects"); 1548 } else { 1549 fatal("pthread_condattr_setclock: %s", os::strerror(status)); 1550 } 1551 } else { 1552 _use_clock_monotonic_condattr = true; 1553 } 1554 } else { 1555 _use_clock_monotonic_condattr = false; 1556 } 1557} 1558 1559void os::Posix::init_2(void) { 1560 log_info(os)("Use of CLOCK_MONOTONIC is%s supported", 1561 (_clock_gettime != NULL ? "" : " not")); 1562 log_info(os)("Use of pthread_condattr_setclock is%s supported", 1563 (_pthread_condattr_setclock != NULL ? "" : " not")); 1564 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with %s", 1565 _use_clock_monotonic_condattr ? "CLOCK_MONOTONIC" : "the default clock"); 1566} 1567 1568#else // !SUPPORTS_CLOCK_MONOTONIC 1569 1570void os::Posix::init(void) { 1571 pthread_init_common(); 1572} 1573 1574void os::Posix::init_2(void) { 1575 log_info(os)("Use of CLOCK_MONOTONIC is not supported"); 1576 log_info(os)("Use of pthread_condattr_setclock is not supported"); 1577 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with the default clock"); 1578} 1579 1580#endif // SUPPORTS_CLOCK_MONOTONIC 1581 1582os::PlatformEvent::PlatformEvent() { 1583 int status = pthread_cond_init(_cond, _condAttr); 1584 assert_status(status == 0, status, "cond_init"); 1585 status = pthread_mutex_init(_mutex, _mutexAttr); 1586 assert_status(status == 0, status, "mutex_init"); 1587 _event = 0; 1588 _nParked = 0; 1589} 1590 1591// Utility to convert the given timeout to an absolute timespec 1592// (based on the appropriate clock) to use with pthread_cond_timewait. 1593// The clock queried here must be the clock used to manage the 1594// timeout of the condition variable. 1595// 1596// The passed in timeout value is either a relative time in nanoseconds 1597// or an absolute time in milliseconds. A relative timeout will be 1598// associated with CLOCK_MONOTONIC if available; otherwise, or if absolute, 1599// the default time-of-day clock will be used. 1600 1601// Given time is a 64-bit value and the time_t used in the timespec is 1602// sometimes a signed-32-bit value we have to watch for overflow if times 1603// way in the future are given. Further on Solaris versions 1604// prior to 10 there is a restriction (see cond_timedwait) that the specified 1605// number of seconds, in abstime, is less than current_time + 100000000. 1606// As it will be over 20 years before "now + 100000000" will overflow we can 1607// ignore overflow and just impose a hard-limit on seconds using the value 1608// of "now + 100000000". This places a limit on the timeout of about 3.17 1609// years from "now". 1610// 1611#define MAX_SECS 100000000 1612 1613// Calculate a new absolute time that is "timeout" nanoseconds from "now". 1614// "unit" indicates the unit of "now_part_sec" (may be nanos or micros depending 1615// on which clock is being used). 1616static void calc_rel_time(timespec* abstime, jlong timeout, jlong now_sec, 1617 jlong now_part_sec, jlong unit) { 1618 time_t max_secs = now_sec + MAX_SECS; 1619 1620 jlong seconds = timeout / NANOUNITS; 1621 timeout %= NANOUNITS; // remaining nanos 1622 1623 if (seconds >= MAX_SECS) { 1624 // More seconds than we can add, so pin to max_secs. 1625 abstime->tv_sec = max_secs; 1626 abstime->tv_nsec = 0; 1627 } else { 1628 abstime->tv_sec = now_sec + seconds; 1629 long nanos = (now_part_sec * (NANOUNITS / unit)) + timeout; 1630 if (nanos >= NANOUNITS) { // overflow 1631 abstime->tv_sec += 1; 1632 nanos -= NANOUNITS; 1633 } 1634 abstime->tv_nsec = nanos; 1635 } 1636} 1637 1638// Unpack the given deadline in milliseconds since the epoch, into the given timespec. 1639// The current time in seconds is also passed in to enforce an upper bound as discussed above. 1640static void unpack_abs_time(timespec* abstime, jlong deadline, jlong now_sec) { 1641 time_t max_secs = now_sec + MAX_SECS; 1642 1643 jlong seconds = deadline / MILLIUNITS; 1644 jlong millis = deadline % MILLIUNITS; 1645 1646 if (seconds >= max_secs) { 1647 // Absolute seconds exceeds allowed max, so pin to max_secs. 1648 abstime->tv_sec = max_secs; 1649 abstime->tv_nsec = 0; 1650 } else { 1651 abstime->tv_sec = seconds; 1652 abstime->tv_nsec = millis * (NANOUNITS / MILLIUNITS); 1653 } 1654} 1655 1656static void to_abstime(timespec* abstime, jlong timeout, bool isAbsolute) { 1657 DEBUG_ONLY(int max_secs = MAX_SECS;) 1658 1659 if (timeout < 0) { 1660 timeout = 0; 1661 } 1662 1663#ifdef SUPPORTS_CLOCK_MONOTONIC 1664 1665 if (_use_clock_monotonic_condattr && !isAbsolute) { 1666 struct timespec now; 1667 int status = _clock_gettime(CLOCK_MONOTONIC, &now); 1668 assert_status(status == 0, status, "clock_gettime"); 1669 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_nsec, NANOUNITS); 1670 DEBUG_ONLY(max_secs += now.tv_sec;) 1671 } else { 1672 1673#else 1674 1675 { // Match the block scope. 1676 1677#endif // SUPPORTS_CLOCK_MONOTONIC 1678 1679 // Time-of-day clock is all we can reliably use. 1680 struct timeval now; 1681 int status = gettimeofday(&now, NULL); 1682 assert_status(status == 0, errno, "gettimeofday"); 1683 if (isAbsolute) { 1684 unpack_abs_time(abstime, timeout, now.tv_sec); 1685 } else { 1686 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_usec, MICROUNITS); 1687 } 1688 DEBUG_ONLY(max_secs += now.tv_sec;) 1689 } 1690 1691 assert(abstime->tv_sec >= 0, "tv_sec < 0"); 1692 assert(abstime->tv_sec <= max_secs, "tv_sec > max_secs"); 1693 assert(abstime->tv_nsec >= 0, "tv_nsec < 0"); 1694 assert(abstime->tv_nsec < NANOUNITS, "tv_nsec >= NANOUNITS"); 1695} 1696 1697// PlatformEvent 1698// 1699// Assumption: 1700// Only one parker can exist on an event, which is why we allocate 1701// them per-thread. Multiple unparkers can coexist. 1702// 1703// _event serves as a restricted-range semaphore. 1704// -1 : thread is blocked, i.e. there is a waiter 1705// 0 : neutral: thread is running or ready, 1706// could have been signaled after a wait started 1707// 1 : signaled - thread is running or ready 1708// 1709// Having three states allows for some detection of bad usage - see 1710// comments on unpark(). 1711 1712void os::PlatformEvent::park() { // AKA "down()" 1713 // Transitions for _event: 1714 // -1 => -1 : illegal 1715 // 1 => 0 : pass - return immediately 1716 // 0 => -1 : block; then set _event to 0 before returning 1717 1718 // Invariant: Only the thread associated with the PlatformEvent 1719 // may call park(). 1720 assert(_nParked == 0, "invariant"); 1721 1722 int v; 1723 1724 // atomically decrement _event 1725 for (;;) { 1726 v = _event; 1727 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break; 1728 } 1729 guarantee(v >= 0, "invariant"); 1730 1731 if (v == 0) { // Do this the hard way by blocking ... 1732 int status = pthread_mutex_lock(_mutex); 1733 assert_status(status == 0, status, "mutex_lock"); 1734 guarantee(_nParked == 0, "invariant"); 1735 ++_nParked; 1736 while (_event < 0) { 1737 // OS-level "spurious wakeups" are ignored 1738 status = pthread_cond_wait(_cond, _mutex); 1739 assert_status(status == 0, status, "cond_wait"); 1740 } 1741 --_nParked; 1742 1743 _event = 0; 1744 status = pthread_mutex_unlock(_mutex); 1745 assert_status(status == 0, status, "mutex_unlock"); 1746 // Paranoia to ensure our locked and lock-free paths interact 1747 // correctly with each other. 1748 OrderAccess::fence(); 1749 } 1750 guarantee(_event >= 0, "invariant"); 1751} 1752 1753int os::PlatformEvent::park(jlong millis) { 1754 // Transitions for _event: 1755 // -1 => -1 : illegal 1756 // 1 => 0 : pass - return immediately 1757 // 0 => -1 : block; then set _event to 0 before returning 1758 1759 // Invariant: Only the thread associated with the Event/PlatformEvent 1760 // may call park(). 1761 assert(_nParked == 0, "invariant"); 1762 1763 int v; 1764 // atomically decrement _event 1765 for (;;) { 1766 v = _event; 1767 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break; 1768 } 1769 guarantee(v >= 0, "invariant"); 1770 1771 if (v == 0) { // Do this the hard way by blocking ... 1772 struct timespec abst; 1773 to_abstime(&abst, millis * (NANOUNITS / MILLIUNITS), false); 1774 1775 int ret = OS_TIMEOUT; 1776 int status = pthread_mutex_lock(_mutex); 1777 assert_status(status == 0, status, "mutex_lock"); 1778 guarantee(_nParked == 0, "invariant"); 1779 ++_nParked; 1780 1781 while (_event < 0) { 1782 status = pthread_cond_timedwait(_cond, _mutex, &abst); 1783 assert_status(status == 0 || status == ETIMEDOUT, 1784 status, "cond_timedwait"); 1785 // OS-level "spurious wakeups" are ignored unless the archaic 1786 // FilterSpuriousWakeups is set false. That flag should be obsoleted. 1787 if (!FilterSpuriousWakeups) break; 1788 if (status == ETIMEDOUT) break; 1789 } 1790 --_nParked; 1791 1792 if (_event >= 0) { 1793 ret = OS_OK; 1794 } 1795 1796 _event = 0; 1797 status = pthread_mutex_unlock(_mutex); 1798 assert_status(status == 0, status, "mutex_unlock"); 1799 // Paranoia to ensure our locked and lock-free paths interact 1800 // correctly with each other. 1801 OrderAccess::fence(); 1802 return ret; 1803 } 1804 return OS_OK; 1805} 1806 1807void os::PlatformEvent::unpark() { 1808 // Transitions for _event: 1809 // 0 => 1 : just return 1810 // 1 => 1 : just return 1811 // -1 => either 0 or 1; must signal target thread 1812 // That is, we can safely transition _event from -1 to either 1813 // 0 or 1. 1814 // See also: "Semaphores in Plan 9" by Mullender & Cox 1815 // 1816 // Note: Forcing a transition from "-1" to "1" on an unpark() means 1817 // that it will take two back-to-back park() calls for the owning 1818 // thread to block. This has the benefit of forcing a spurious return 1819 // from the first park() call after an unpark() call which will help 1820 // shake out uses of park() and unpark() without checking state conditions 1821 // properly. This spurious return doesn't manifest itself in any user code 1822 // but only in the correctly written condition checking loops of ObjectMonitor, 1823 // Mutex/Monitor, Thread::muxAcquire and os::sleep 1824 1825 if (Atomic::xchg(1, &_event) >= 0) return; 1826 1827 int status = pthread_mutex_lock(_mutex); 1828 assert_status(status == 0, status, "mutex_lock"); 1829 int anyWaiters = _nParked; 1830 assert(anyWaiters == 0 || anyWaiters == 1, "invariant"); 1831 status = pthread_mutex_unlock(_mutex); 1832 assert_status(status == 0, status, "mutex_unlock"); 1833 1834 // Note that we signal() *after* dropping the lock for "immortal" Events. 1835 // This is safe and avoids a common class of futile wakeups. In rare 1836 // circumstances this can cause a thread to return prematurely from 1837 // cond_{timed}wait() but the spurious wakeup is benign and the victim 1838 // will simply re-test the condition and re-park itself. 1839 // This provides particular benefit if the underlying platform does not 1840 // provide wait morphing. 1841 1842 if (anyWaiters != 0) { 1843 status = pthread_cond_signal(_cond); 1844 assert_status(status == 0, status, "cond_signal"); 1845 } 1846} 1847 1848// JSR166 support 1849 1850 os::PlatformParker::PlatformParker() { 1851 int status; 1852 status = pthread_cond_init(&_cond[REL_INDEX], _condAttr); 1853 assert_status(status == 0, status, "cond_init rel"); 1854 status = pthread_cond_init(&_cond[ABS_INDEX], NULL); 1855 assert_status(status == 0, status, "cond_init abs"); 1856 status = pthread_mutex_init(_mutex, _mutexAttr); 1857 assert_status(status == 0, status, "mutex_init"); 1858 _cur_index = -1; // mark as unused 1859} 1860 1861// Parker::park decrements count if > 0, else does a condvar wait. Unpark 1862// sets count to 1 and signals condvar. Only one thread ever waits 1863// on the condvar. Contention seen when trying to park implies that someone 1864// is unparking you, so don't wait. And spurious returns are fine, so there 1865// is no need to track notifications. 1866 1867void Parker::park(bool isAbsolute, jlong time) { 1868 1869 // Optional fast-path check: 1870 // Return immediately if a permit is available. 1871 // We depend on Atomic::xchg() having full barrier semantics 1872 // since we are doing a lock-free update to _counter. 1873 if (Atomic::xchg(0, &_counter) > 0) return; 1874 1875 Thread* thread = Thread::current(); 1876 assert(thread->is_Java_thread(), "Must be JavaThread"); 1877 JavaThread *jt = (JavaThread *)thread; 1878 1879 // Optional optimization -- avoid state transitions if there's 1880 // an interrupt pending. 1881 if (Thread::is_interrupted(thread, false)) { 1882 return; 1883 } 1884 1885 // Next, demultiplex/decode time arguments 1886 struct timespec absTime; 1887 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all 1888 return; 1889 } 1890 if (time > 0) { 1891 to_abstime(&absTime, time, isAbsolute); 1892 } 1893 1894 // Enter safepoint region 1895 // Beware of deadlocks such as 6317397. 1896 // The per-thread Parker:: mutex is a classic leaf-lock. 1897 // In particular a thread must never block on the Threads_lock while 1898 // holding the Parker:: mutex. If safepoints are pending both the 1899 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 1900 ThreadBlockInVM tbivm(jt); 1901 1902 // Don't wait if cannot get lock since interference arises from 1903 // unparking. Also re-check interrupt before trying wait. 1904 if (Thread::is_interrupted(thread, false) || 1905 pthread_mutex_trylock(_mutex) != 0) { 1906 return; 1907 } 1908 1909 int status; 1910 if (_counter > 0) { // no wait needed 1911 _counter = 0; 1912 status = pthread_mutex_unlock(_mutex); 1913 assert_status(status == 0, status, "invariant"); 1914 // Paranoia to ensure our locked and lock-free paths interact 1915 // correctly with each other and Java-level accesses. 1916 OrderAccess::fence(); 1917 return; 1918 } 1919 1920 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 1921 jt->set_suspend_equivalent(); 1922 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 1923 1924 assert(_cur_index == -1, "invariant"); 1925 if (time == 0) { 1926 _cur_index = REL_INDEX; // arbitrary choice when not timed 1927 status = pthread_cond_wait(&_cond[_cur_index], _mutex); 1928 assert_status(status == 0, status, "cond_timedwait"); 1929 } 1930 else { 1931 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 1932 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); 1933 assert_status(status == 0 || status == ETIMEDOUT, 1934 status, "cond_timedwait"); 1935 } 1936 _cur_index = -1; 1937 1938 _counter = 0; 1939 status = pthread_mutex_unlock(_mutex); 1940 assert_status(status == 0, status, "invariant"); 1941 // Paranoia to ensure our locked and lock-free paths interact 1942 // correctly with each other and Java-level accesses. 1943 OrderAccess::fence(); 1944 1945 // If externally suspended while waiting, re-suspend 1946 if (jt->handle_special_suspend_equivalent_condition()) { 1947 jt->java_suspend_self(); 1948 } 1949} 1950 1951void Parker::unpark() { 1952 int status = pthread_mutex_lock(_mutex); 1953 assert_status(status == 0, status, "invariant"); 1954 const int s = _counter; 1955 _counter = 1; 1956 // must capture correct index before unlocking 1957 int index = _cur_index; 1958 status = pthread_mutex_unlock(_mutex); 1959 assert_status(status == 0, status, "invariant"); 1960 1961 // Note that we signal() *after* dropping the lock for "immortal" Events. 1962 // This is safe and avoids a common class of futile wakeups. In rare 1963 // circumstances this can cause a thread to return prematurely from 1964 // cond_{timed}wait() but the spurious wakeup is benign and the victim 1965 // will simply re-test the condition and re-park itself. 1966 // This provides particular benefit if the underlying platform does not 1967 // provide wait morphing. 1968 1969 if (s < 1 && index != -1) { 1970 // thread is definitely parked 1971 status = pthread_cond_signal(&_cond[index]); 1972 assert_status(status == 0, status, "invariant"); 1973 } 1974} 1975 1976 1977#endif // !SOLARIS 1978