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 "jvm.h" 26 #include "utilities/globalDefinitions.hpp" 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/mman.h> 44 #include <sys/resource.h> 45 #include <sys/utsname.h> 46 #include <time.h> 47 #include <unistd.h> 48 49 // Todo: provide a os::get_max_process_id() or similar. Number of processes 50 // may have been configured, can be read more accurately from proc fs etc. 51 #ifndef MAX_PID 52 #define MAX_PID INT_MAX 53 #endif 54 #define IS_VALID_PID(p) (p > 0 && p < MAX_PID) 55 56 #ifndef MAP_ANONYMOUS 57 #define MAP_ANONYMOUS MAP_ANON 58 #endif 59 60 #define check_with_errno(check_type, cond, msg) \ 61 do { \ 62 int err = errno; \ 63 check_type(cond, "%s; error='%s' (errno=%s)", msg, os::strerror(err), \ 64 os::errno_name(err)); \ 65 } while (false) 66 67 #define assert_with_errno(cond, msg) check_with_errno(assert, cond, msg) 68 #define guarantee_with_errno(cond, msg) check_with_errno(guarantee, cond, msg) 69 70 // Check core dump limit and report possible place where core can be found 71 void os::check_dump_limit(char* buffer, size_t bufferSize) { 72 if (!FLAG_IS_DEFAULT(CreateCoredumpOnCrash) && !CreateCoredumpOnCrash) { 73 jio_snprintf(buffer, bufferSize, "CreateCoredumpOnCrash is disabled from command line"); 74 VMError::record_coredump_status(buffer, false); 75 return; 76 } 77 78 int n; 79 struct rlimit rlim; 80 bool success; 81 82 char core_path[PATH_MAX]; 83 n = get_core_path(core_path, PATH_MAX); 84 85 if (n <= 0) { 86 jio_snprintf(buffer, bufferSize, "core.%d (may not exist)", current_process_id()); 87 success = true; 88 #ifdef LINUX 89 } else if (core_path[0] == '"') { // redirect to user process 90 jio_snprintf(buffer, bufferSize, "Core dumps may be processed with %s", core_path); 91 success = true; 92 #endif 93 } else if (getrlimit(RLIMIT_CORE, &rlim) != 0) { 94 jio_snprintf(buffer, bufferSize, "%s (may not exist)", core_path); 95 success = true; 96 } else { 97 switch(rlim.rlim_cur) { 98 case RLIM_INFINITY: 99 jio_snprintf(buffer, bufferSize, "%s", core_path); 100 success = true; 101 break; 102 case 0: 103 jio_snprintf(buffer, bufferSize, "Core dumps have been disabled. To enable core dumping, try \"ulimit -c unlimited\" before starting Java again"); 104 success = false; 105 break; 106 default: 107 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); 108 success = true; 109 break; 110 } 111 } 112 113 VMError::record_coredump_status(buffer, success); 114 } 115 116 int os::get_native_stack(address* stack, int frames, int toSkip) { 117 int frame_idx = 0; 118 int num_of_frames; // number of frames captured 119 frame fr = os::current_frame(); 120 while (fr.pc() && frame_idx < frames) { 121 if (toSkip > 0) { 122 toSkip --; 123 } else { 124 stack[frame_idx ++] = fr.pc(); 125 } 126 if (fr.fp() == NULL || fr.cb() != NULL || 127 fr.sender_pc() == NULL || os::is_first_C_frame(&fr)) break; 128 129 if (fr.sender_pc() && !os::is_first_C_frame(&fr)) { 130 fr = os::get_sender_for_C_frame(&fr); 131 } else { 132 break; 133 } 134 } 135 num_of_frames = frame_idx; 136 for (; frame_idx < frames; frame_idx ++) { 137 stack[frame_idx] = NULL; 138 } 139 140 return num_of_frames; 141 } 142 143 144 bool os::unsetenv(const char* name) { 145 assert(name != NULL, "Null pointer"); 146 return (::unsetenv(name) == 0); 147 } 148 149 int os::get_last_error() { 150 return errno; 151 } 152 153 bool os::is_debugger_attached() { 154 // not implemented 155 return false; 156 } 157 158 void os::wait_for_keypress_at_exit(void) { 159 // don't do anything on posix platforms 160 return; 161 } 162 163 int os::create_file_for_heap(const char* dir) { 164 165 const char name_template[] = "/jvmheap.XXXXXX"; 166 167 char *fullname = (char*)os::malloc((strlen(dir) + strlen(name_template) + 1), mtInternal); 168 if (fullname == NULL) { 169 vm_exit_during_initialization(err_msg("Malloc failed during creation of backing file for heap (%s)", os::strerror(errno))); 170 return -1; 171 } 172 (void)strncpy(fullname, dir, strlen(dir)+1); 173 (void)strncat(fullname, name_template, strlen(name_template)); 174 175 os::native_path(fullname); 176 177 sigset_t set, oldset; 178 int ret = sigfillset(&set); 179 assert_with_errno(ret == 0, "sigfillset returned error"); 180 181 // set the file creation mask. 182 mode_t file_mode = S_IRUSR | S_IWUSR; 183 184 // create a new file. 185 int fd = mkstemp(fullname); 186 187 if (fd < 0) { 188 warning("Could not create file for heap with template %s", fullname); 189 os::free(fullname); 190 return -1; 191 } 192 193 // delete the name from the filesystem. When 'fd' is closed, the file (and space) will be deleted. 194 ret = unlink(fullname); 195 assert_with_errno(ret == 0, "unlink returned error"); 196 197 os::free(fullname); 198 return fd; 199 } 200 201 static char* reserve_mmapped_memory(size_t bytes, char* requested_addr) { 202 char * addr; 203 int flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 204 if (requested_addr != NULL) { 205 assert((uintptr_t)requested_addr % os::vm_page_size() == 0, "Requested address should be aligned to OS page size"); 206 flags |= MAP_FIXED; 207 } 208 209 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 210 // touch an uncommitted page. Otherwise, the read/write might 211 // succeed if we have enough swap space to back the physical page. 212 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 213 flags, -1, 0); 214 215 if (addr != MAP_FAILED) { 216 MemTracker::record_virtual_memory_reserve((address)addr, bytes, CALLER_PC); 217 return addr; 218 } 219 return NULL; 220 } 221 222 static int util_posix_fallocate(int fd, off_t offset, off_t len) { 223 #ifdef __APPLE__ 224 fstore_t store = { F_ALLOCATECONTIG, F_PEOFPOSMODE, 0, len }; 225 // First we try to get a continuous chunk of disk space 226 int ret = fcntl(fd, F_PREALLOCATE, &store); 227 if (ret == -1) { 228 // Maybe we are too fragmented, try to allocate non-continuous range 229 store.fst_flags = F_ALLOCATEALL; 230 ret = fcntl(fd, F_PREALLOCATE, &store); 231 } 232 if(ret != -1) { 233 return ftruncate(fd, len); 234 } 235 return -1; 236 #else 237 return posix_fallocate(fd, offset, len); 238 #endif 239 } 240 241 // Map the given address range to the provided file descriptor. 242 char* os::map_memory_to_file(char* base, size_t size, int fd) { 243 assert(fd != -1, "File descriptor is not valid"); 244 245 // allocate space for the file 246 if (util_posix_fallocate(fd, 0, (off_t)size) != 0) { 247 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory.")); 248 return NULL; 249 } 250 251 int prot = PROT_READ | PROT_WRITE; 252 int flags = MAP_SHARED; 253 if (base != NULL) { 254 flags |= MAP_FIXED; 255 } 256 char* addr = (char*)mmap(base, size, prot, flags, fd, 0); 257 258 if (addr == MAP_FAILED) { 259 return NULL; 260 } 261 if (base != NULL && addr != base) { 262 if (!os::release_memory(addr, size)) { 263 warning("Could not release memory on unsuccessful file mapping"); 264 } 265 return NULL; 266 } 267 return addr; 268 } 269 270 char* os::replace_existing_mapping_with_file_mapping(char* base, size_t size, int fd) { 271 assert(fd != -1, "File descriptor is not valid"); 272 assert(base != NULL, "Base cannot be NULL"); 273 274 return map_memory_to_file(base, size, fd); 275 } 276 277 // Multiple threads can race in this code, and can remap over each other with MAP_FIXED, 278 // so on posix, unmap the section at the start and at the end of the chunk that we mapped 279 // rather than unmapping and remapping the whole chunk to get requested alignment. 280 char* os::reserve_memory_aligned(size_t size, size_t alignment, int file_desc) { 281 assert((alignment & (os::vm_allocation_granularity() - 1)) == 0, 282 "Alignment must be a multiple of allocation granularity (page size)"); 283 assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned"); 284 285 size_t extra_size = size + alignment; 286 assert(extra_size >= size, "overflow, size is too large to allow alignment"); 287 288 char* extra_base; 289 if (file_desc != -1) { 290 // For file mapping, we do not call os:reserve_memory(extra_size, NULL, alignment, file_desc) because 291 // we need to deal with shrinking of the file space later when we release extra memory after alignment. 292 // We also cannot called os:reserve_memory() with file_desc set to -1 because on aix we might get SHM memory. 293 // So here to call a helper function while reserve memory for us. After we have a aligned base, 294 // we will replace anonymous mapping with file mapping. 295 extra_base = reserve_mmapped_memory(extra_size, NULL); 296 if (extra_base != NULL) { 297 MemTracker::record_virtual_memory_reserve((address)extra_base, extra_size, CALLER_PC); 298 } 299 } else { 300 extra_base = os::reserve_memory(extra_size, NULL, alignment); 301 } 302 303 if (extra_base == NULL) { 304 return NULL; 305 } 306 307 // Do manual alignment 308 char* aligned_base = align_up(extra_base, alignment); 309 310 // [ | | ] 311 // ^ extra_base 312 // ^ extra_base + begin_offset == aligned_base 313 // extra_base + begin_offset + size ^ 314 // extra_base + extra_size ^ 315 // |<>| == begin_offset 316 // end_offset == |<>| 317 size_t begin_offset = aligned_base - extra_base; 318 size_t end_offset = (extra_base + extra_size) - (aligned_base + size); 319 320 if (begin_offset > 0) { 321 os::release_memory(extra_base, begin_offset); 322 } 323 324 if (end_offset > 0) { 325 os::release_memory(extra_base + begin_offset + size, end_offset); 326 } 327 328 if (file_desc != -1) { 329 // After we have an aligned address, we can replace anonymous mapping with file mapping 330 if (replace_existing_mapping_with_file_mapping(aligned_base, size, file_desc) == NULL) { 331 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory")); 332 } 333 MemTracker::record_virtual_memory_commit((address)aligned_base, size, CALLER_PC); 334 } 335 return aligned_base; 336 } 337 338 int os::log_vsnprintf(char* buf, size_t len, const char* fmt, va_list args) { 339 return vsnprintf(buf, len, fmt, args); 340 } 341 342 int os::get_fileno(FILE* fp) { 343 return NOT_AIX(::)fileno(fp); 344 } 345 346 struct tm* os::gmtime_pd(const time_t* clock, struct tm* res) { 347 return gmtime_r(clock, res); 348 } 349 350 void os::Posix::print_load_average(outputStream* st) { 351 st->print("load average:"); 352 double loadavg[3]; 353 os::loadavg(loadavg, 3); 354 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]); 355 st->cr(); 356 } 357 358 void os::Posix::print_rlimit_info(outputStream* st) { 359 st->print("rlimit:"); 360 struct rlimit rlim; 361 362 st->print(" STACK "); 363 getrlimit(RLIMIT_STACK, &rlim); 364 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 365 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); 366 367 st->print(", CORE "); 368 getrlimit(RLIMIT_CORE, &rlim); 369 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 370 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); 371 372 // Isn't there on solaris 373 #if defined(AIX) 374 st->print(", NPROC "); 375 st->print("%d", sysconf(_SC_CHILD_MAX)); 376 #elif !defined(SOLARIS) 377 st->print(", NPROC "); 378 getrlimit(RLIMIT_NPROC, &rlim); 379 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 380 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur)); 381 #endif 382 383 st->print(", NOFILE "); 384 getrlimit(RLIMIT_NOFILE, &rlim); 385 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 386 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur)); 387 388 st->print(", AS "); 389 getrlimit(RLIMIT_AS, &rlim); 390 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 391 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); 392 393 st->print(", DATA "); 394 getrlimit(RLIMIT_DATA, &rlim); 395 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 396 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); 397 398 st->print(", FSIZE "); 399 getrlimit(RLIMIT_FSIZE, &rlim); 400 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 401 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); 402 403 st->cr(); 404 } 405 406 void os::Posix::print_uname_info(outputStream* st) { 407 // kernel 408 st->print("uname:"); 409 struct utsname name; 410 uname(&name); 411 st->print("%s ", name.sysname); 412 #ifdef ASSERT 413 st->print("%s ", name.nodename); 414 #endif 415 st->print("%s ", name.release); 416 st->print("%s ", name.version); 417 st->print("%s", name.machine); 418 st->cr(); 419 } 420 421 bool os::get_host_name(char* buf, size_t buflen) { 422 struct utsname name; 423 uname(&name); 424 jio_snprintf(buf, buflen, "%s", name.nodename); 425 return true; 426 } 427 428 bool os::has_allocatable_memory_limit(julong* limit) { 429 struct rlimit rlim; 430 int getrlimit_res = getrlimit(RLIMIT_AS, &rlim); 431 // if there was an error when calling getrlimit, assume that there is no limitation 432 // on virtual memory. 433 bool result; 434 if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) { 435 result = false; 436 } else { 437 *limit = (julong)rlim.rlim_cur; 438 result = true; 439 } 440 #ifdef _LP64 441 return result; 442 #else 443 // arbitrary virtual space limit for 32 bit Unices found by testing. If 444 // getrlimit above returned a limit, bound it with this limit. Otherwise 445 // directly use it. 446 const julong max_virtual_limit = (julong)3800*M; 447 if (result) { 448 *limit = MIN2(*limit, max_virtual_limit); 449 } else { 450 *limit = max_virtual_limit; 451 } 452 453 // bound by actually allocatable memory. The algorithm uses two bounds, an 454 // upper and a lower limit. The upper limit is the current highest amount of 455 // memory that could not be allocated, the lower limit is the current highest 456 // amount of memory that could be allocated. 457 // The algorithm iteratively refines the result by halving the difference 458 // between these limits, updating either the upper limit (if that value could 459 // not be allocated) or the lower limit (if the that value could be allocated) 460 // until the difference between these limits is "small". 461 462 // the minimum amount of memory we care about allocating. 463 const julong min_allocation_size = M; 464 465 julong upper_limit = *limit; 466 467 // first check a few trivial cases 468 if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) { 469 *limit = upper_limit; 470 } else if (!is_allocatable(min_allocation_size)) { 471 // we found that not even min_allocation_size is allocatable. Return it 472 // anyway. There is no point to search for a better value any more. 473 *limit = min_allocation_size; 474 } else { 475 // perform the binary search. 476 julong lower_limit = min_allocation_size; 477 while ((upper_limit - lower_limit) > min_allocation_size) { 478 julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit; 479 temp_limit = align_down(temp_limit, min_allocation_size); 480 if (is_allocatable(temp_limit)) { 481 lower_limit = temp_limit; 482 } else { 483 upper_limit = temp_limit; 484 } 485 } 486 *limit = lower_limit; 487 } 488 return true; 489 #endif 490 } 491 492 const char* os::get_current_directory(char *buf, size_t buflen) { 493 return getcwd(buf, buflen); 494 } 495 496 FILE* os::open(int fd, const char* mode) { 497 return ::fdopen(fd, mode); 498 } 499 500 void os::flockfile(FILE* fp) { 501 ::flockfile(fp); 502 } 503 504 void os::funlockfile(FILE* fp) { 505 ::funlockfile(fp); 506 } 507 508 // Builds a platform dependent Agent_OnLoad_<lib_name> function name 509 // which is used to find statically linked in agents. 510 // Parameters: 511 // sym_name: Symbol in library we are looking for 512 // lib_name: Name of library to look in, NULL for shared libs. 513 // is_absolute_path == true if lib_name is absolute path to agent 514 // such as "/a/b/libL.so" 515 // == false if only the base name of the library is passed in 516 // such as "L" 517 char* os::build_agent_function_name(const char *sym_name, const char *lib_name, 518 bool is_absolute_path) { 519 char *agent_entry_name; 520 size_t len; 521 size_t name_len; 522 size_t prefix_len = strlen(JNI_LIB_PREFIX); 523 size_t suffix_len = strlen(JNI_LIB_SUFFIX); 524 const char *start; 525 526 if (lib_name != NULL) { 527 name_len = strlen(lib_name); 528 if (is_absolute_path) { 529 // Need to strip path, prefix and suffix 530 if ((start = strrchr(lib_name, *os::file_separator())) != NULL) { 531 lib_name = ++start; 532 } 533 if (strlen(lib_name) <= (prefix_len + suffix_len)) { 534 return NULL; 535 } 536 lib_name += prefix_len; 537 name_len = strlen(lib_name) - suffix_len; 538 } 539 } 540 len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2; 541 agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread); 542 if (agent_entry_name == NULL) { 543 return NULL; 544 } 545 strcpy(agent_entry_name, sym_name); 546 if (lib_name != NULL) { 547 strcat(agent_entry_name, "_"); 548 strncat(agent_entry_name, lib_name, name_len); 549 } 550 return agent_entry_name; 551 } 552 553 int os::sleep(Thread* thread, jlong millis, bool interruptible) { 554 assert(thread == Thread::current(), "thread consistency check"); 555 556 ParkEvent * const slp = thread->_SleepEvent ; 557 slp->reset() ; 558 OrderAccess::fence() ; 559 560 if (interruptible) { 561 jlong prevtime = javaTimeNanos(); 562 563 for (;;) { 564 if (os::is_interrupted(thread, true)) { 565 return OS_INTRPT; 566 } 567 568 jlong newtime = javaTimeNanos(); 569 570 if (newtime - prevtime < 0) { 571 // time moving backwards, should only happen if no monotonic clock 572 // not a guarantee() because JVM should not abort on kernel/glibc bugs 573 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected in os::sleep(interruptible)"); 574 } else { 575 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 576 } 577 578 if (millis <= 0) { 579 return OS_OK; 580 } 581 582 prevtime = newtime; 583 584 { 585 assert(thread->is_Java_thread(), "sanity check"); 586 JavaThread *jt = (JavaThread *) thread; 587 ThreadBlockInVM tbivm(jt); 588 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 589 590 jt->set_suspend_equivalent(); 591 // cleared by handle_special_suspend_equivalent_condition() or 592 // java_suspend_self() via check_and_wait_while_suspended() 593 594 slp->park(millis); 595 596 // were we externally suspended while we were waiting? 597 jt->check_and_wait_while_suspended(); 598 } 599 } 600 } else { 601 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 602 jlong prevtime = javaTimeNanos(); 603 604 for (;;) { 605 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 606 // the 1st iteration ... 607 jlong newtime = javaTimeNanos(); 608 609 if (newtime - prevtime < 0) { 610 // time moving backwards, should only happen if no monotonic clock 611 // not a guarantee() because JVM should not abort on kernel/glibc bugs 612 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected on os::sleep(!interruptible)"); 613 } else { 614 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 615 } 616 617 if (millis <= 0) break ; 618 619 prevtime = newtime; 620 slp->park(millis); 621 } 622 return OS_OK ; 623 } 624 } 625 626 //////////////////////////////////////////////////////////////////////////////// 627 // interrupt support 628 629 void os::interrupt(Thread* thread) { 630 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 631 "possibility of dangling Thread pointer"); 632 633 OSThread* osthread = thread->osthread(); 634 635 if (!osthread->interrupted()) { 636 osthread->set_interrupted(true); 637 // More than one thread can get here with the same value of osthread, 638 // resulting in multiple notifications. We do, however, want the store 639 // to interrupted() to be visible to other threads before we execute unpark(). 640 OrderAccess::fence(); 641 ParkEvent * const slp = thread->_SleepEvent ; 642 if (slp != NULL) slp->unpark() ; 643 } 644 645 // For JSR166. Unpark even if interrupt status already was set 646 if (thread->is_Java_thread()) 647 ((JavaThread*)thread)->parker()->unpark(); 648 649 ParkEvent * ev = thread->_ParkEvent ; 650 if (ev != NULL) ev->unpark() ; 651 652 } 653 654 bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 655 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 656 "possibility of dangling Thread pointer"); 657 658 OSThread* osthread = thread->osthread(); 659 660 bool interrupted = osthread->interrupted(); 661 662 // NOTE that since there is no "lock" around the interrupt and 663 // is_interrupted operations, there is the possibility that the 664 // interrupted flag (in osThread) will be "false" but that the 665 // low-level events will be in the signaled state. This is 666 // intentional. The effect of this is that Object.wait() and 667 // LockSupport.park() will appear to have a spurious wakeup, which 668 // is allowed and not harmful, and the possibility is so rare that 669 // it is not worth the added complexity to add yet another lock. 670 // For the sleep event an explicit reset is performed on entry 671 // to os::sleep, so there is no early return. It has also been 672 // recommended not to put the interrupted flag into the "event" 673 // structure because it hides the issue. 674 if (interrupted && clear_interrupted) { 675 osthread->set_interrupted(false); 676 // consider thread->_SleepEvent->reset() ... optional optimization 677 } 678 679 return interrupted; 680 } 681 682 683 684 static const struct { 685 int sig; const char* name; 686 } 687 g_signal_info[] = 688 { 689 { SIGABRT, "SIGABRT" }, 690 #ifdef SIGAIO 691 { SIGAIO, "SIGAIO" }, 692 #endif 693 { SIGALRM, "SIGALRM" }, 694 #ifdef SIGALRM1 695 { SIGALRM1, "SIGALRM1" }, 696 #endif 697 { SIGBUS, "SIGBUS" }, 698 #ifdef SIGCANCEL 699 { SIGCANCEL, "SIGCANCEL" }, 700 #endif 701 { SIGCHLD, "SIGCHLD" }, 702 #ifdef SIGCLD 703 { SIGCLD, "SIGCLD" }, 704 #endif 705 { SIGCONT, "SIGCONT" }, 706 #ifdef SIGCPUFAIL 707 { SIGCPUFAIL, "SIGCPUFAIL" }, 708 #endif 709 #ifdef SIGDANGER 710 { SIGDANGER, "SIGDANGER" }, 711 #endif 712 #ifdef SIGDIL 713 { SIGDIL, "SIGDIL" }, 714 #endif 715 #ifdef SIGEMT 716 { SIGEMT, "SIGEMT" }, 717 #endif 718 { SIGFPE, "SIGFPE" }, 719 #ifdef SIGFREEZE 720 { SIGFREEZE, "SIGFREEZE" }, 721 #endif 722 #ifdef SIGGFAULT 723 { SIGGFAULT, "SIGGFAULT" }, 724 #endif 725 #ifdef SIGGRANT 726 { SIGGRANT, "SIGGRANT" }, 727 #endif 728 { SIGHUP, "SIGHUP" }, 729 { SIGILL, "SIGILL" }, 730 { SIGINT, "SIGINT" }, 731 #ifdef SIGIO 732 { SIGIO, "SIGIO" }, 733 #endif 734 #ifdef SIGIOINT 735 { SIGIOINT, "SIGIOINT" }, 736 #endif 737 #ifdef SIGIOT 738 // SIGIOT is there for BSD compatibility, but on most Unices just a 739 // synonym for SIGABRT. The result should be "SIGABRT", not 740 // "SIGIOT". 741 #if (SIGIOT != SIGABRT ) 742 { SIGIOT, "SIGIOT" }, 743 #endif 744 #endif 745 #ifdef SIGKAP 746 { SIGKAP, "SIGKAP" }, 747 #endif 748 { SIGKILL, "SIGKILL" }, 749 #ifdef SIGLOST 750 { SIGLOST, "SIGLOST" }, 751 #endif 752 #ifdef SIGLWP 753 { SIGLWP, "SIGLWP" }, 754 #endif 755 #ifdef SIGLWPTIMER 756 { SIGLWPTIMER, "SIGLWPTIMER" }, 757 #endif 758 #ifdef SIGMIGRATE 759 { SIGMIGRATE, "SIGMIGRATE" }, 760 #endif 761 #ifdef SIGMSG 762 { SIGMSG, "SIGMSG" }, 763 #endif 764 { SIGPIPE, "SIGPIPE" }, 765 #ifdef SIGPOLL 766 { SIGPOLL, "SIGPOLL" }, 767 #endif 768 #ifdef SIGPRE 769 { SIGPRE, "SIGPRE" }, 770 #endif 771 { SIGPROF, "SIGPROF" }, 772 #ifdef SIGPTY 773 { SIGPTY, "SIGPTY" }, 774 #endif 775 #ifdef SIGPWR 776 { SIGPWR, "SIGPWR" }, 777 #endif 778 { SIGQUIT, "SIGQUIT" }, 779 #ifdef SIGRECONFIG 780 { SIGRECONFIG, "SIGRECONFIG" }, 781 #endif 782 #ifdef SIGRECOVERY 783 { SIGRECOVERY, "SIGRECOVERY" }, 784 #endif 785 #ifdef SIGRESERVE 786 { SIGRESERVE, "SIGRESERVE" }, 787 #endif 788 #ifdef SIGRETRACT 789 { SIGRETRACT, "SIGRETRACT" }, 790 #endif 791 #ifdef SIGSAK 792 { SIGSAK, "SIGSAK" }, 793 #endif 794 { SIGSEGV, "SIGSEGV" }, 795 #ifdef SIGSOUND 796 { SIGSOUND, "SIGSOUND" }, 797 #endif 798 #ifdef SIGSTKFLT 799 { SIGSTKFLT, "SIGSTKFLT" }, 800 #endif 801 { SIGSTOP, "SIGSTOP" }, 802 { SIGSYS, "SIGSYS" }, 803 #ifdef SIGSYSERROR 804 { SIGSYSERROR, "SIGSYSERROR" }, 805 #endif 806 #ifdef SIGTALRM 807 { SIGTALRM, "SIGTALRM" }, 808 #endif 809 { SIGTERM, "SIGTERM" }, 810 #ifdef SIGTHAW 811 { SIGTHAW, "SIGTHAW" }, 812 #endif 813 { SIGTRAP, "SIGTRAP" }, 814 #ifdef SIGTSTP 815 { SIGTSTP, "SIGTSTP" }, 816 #endif 817 { SIGTTIN, "SIGTTIN" }, 818 { SIGTTOU, "SIGTTOU" }, 819 #ifdef SIGURG 820 { SIGURG, "SIGURG" }, 821 #endif 822 { SIGUSR1, "SIGUSR1" }, 823 { SIGUSR2, "SIGUSR2" }, 824 #ifdef SIGVIRT 825 { SIGVIRT, "SIGVIRT" }, 826 #endif 827 { SIGVTALRM, "SIGVTALRM" }, 828 #ifdef SIGWAITING 829 { SIGWAITING, "SIGWAITING" }, 830 #endif 831 #ifdef SIGWINCH 832 { SIGWINCH, "SIGWINCH" }, 833 #endif 834 #ifdef SIGWINDOW 835 { SIGWINDOW, "SIGWINDOW" }, 836 #endif 837 { SIGXCPU, "SIGXCPU" }, 838 { SIGXFSZ, "SIGXFSZ" }, 839 #ifdef SIGXRES 840 { SIGXRES, "SIGXRES" }, 841 #endif 842 { -1, NULL } 843 }; 844 845 // Returned string is a constant. For unknown signals "UNKNOWN" is returned. 846 const char* os::Posix::get_signal_name(int sig, char* out, size_t outlen) { 847 848 const char* ret = NULL; 849 850 #ifdef SIGRTMIN 851 if (sig >= SIGRTMIN && sig <= SIGRTMAX) { 852 if (sig == SIGRTMIN) { 853 ret = "SIGRTMIN"; 854 } else if (sig == SIGRTMAX) { 855 ret = "SIGRTMAX"; 856 } else { 857 jio_snprintf(out, outlen, "SIGRTMIN+%d", sig - SIGRTMIN); 858 return out; 859 } 860 } 861 #endif 862 863 if (sig > 0) { 864 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) { 865 if (g_signal_info[idx].sig == sig) { 866 ret = g_signal_info[idx].name; 867 break; 868 } 869 } 870 } 871 872 if (!ret) { 873 if (!is_valid_signal(sig)) { 874 ret = "INVALID"; 875 } else { 876 ret = "UNKNOWN"; 877 } 878 } 879 880 if (out && outlen > 0) { 881 strncpy(out, ret, outlen); 882 out[outlen - 1] = '\0'; 883 } 884 return out; 885 } 886 887 int os::Posix::get_signal_number(const char* signal_name) { 888 char tmp[30]; 889 const char* s = signal_name; 890 if (s[0] != 'S' || s[1] != 'I' || s[2] != 'G') { 891 jio_snprintf(tmp, sizeof(tmp), "SIG%s", signal_name); 892 s = tmp; 893 } 894 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) { 895 if (strcmp(g_signal_info[idx].name, s) == 0) { 896 return g_signal_info[idx].sig; 897 } 898 } 899 return -1; 900 } 901 902 int os::get_signal_number(const char* signal_name) { 903 return os::Posix::get_signal_number(signal_name); 904 } 905 906 // Returns true if signal number is valid. 907 bool os::Posix::is_valid_signal(int sig) { 908 // MacOS not really POSIX compliant: sigaddset does not return 909 // an error for invalid signal numbers. However, MacOS does not 910 // support real time signals and simply seems to have just 33 911 // signals with no holes in the signal range. 912 #ifdef __APPLE__ 913 return sig >= 1 && sig < NSIG; 914 #else 915 // Use sigaddset to check for signal validity. 916 sigset_t set; 917 sigemptyset(&set); 918 if (sigaddset(&set, sig) == -1 && errno == EINVAL) { 919 return false; 920 } 921 return true; 922 #endif 923 } 924 925 // Returns: 926 // NULL for an invalid signal number 927 // "SIG<num>" for a valid but unknown signal number 928 // signal name otherwise. 929 const char* os::exception_name(int sig, char* buf, size_t size) { 930 if (!os::Posix::is_valid_signal(sig)) { 931 return NULL; 932 } 933 const char* const name = os::Posix::get_signal_name(sig, buf, size); 934 if (strcmp(name, "UNKNOWN") == 0) { 935 jio_snprintf(buf, size, "SIG%d", sig); 936 } 937 return buf; 938 } 939 940 #define NUM_IMPORTANT_SIGS 32 941 // Returns one-line short description of a signal set in a user provided buffer. 942 const char* os::Posix::describe_signal_set_short(const sigset_t* set, char* buffer, size_t buf_size) { 943 assert(buf_size == (NUM_IMPORTANT_SIGS + 1), "wrong buffer size"); 944 // Note: for shortness, just print out the first 32. That should 945 // cover most of the useful ones, apart from realtime signals. 946 for (int sig = 1; sig <= NUM_IMPORTANT_SIGS; sig++) { 947 const int rc = sigismember(set, sig); 948 if (rc == -1 && errno == EINVAL) { 949 buffer[sig-1] = '?'; 950 } else { 951 buffer[sig-1] = rc == 0 ? '0' : '1'; 952 } 953 } 954 buffer[NUM_IMPORTANT_SIGS] = 0; 955 return buffer; 956 } 957 958 // Prints one-line description of a signal set. 959 void os::Posix::print_signal_set_short(outputStream* st, const sigset_t* set) { 960 char buf[NUM_IMPORTANT_SIGS + 1]; 961 os::Posix::describe_signal_set_short(set, buf, sizeof(buf)); 962 st->print("%s", buf); 963 } 964 965 // Writes one-line description of a combination of sigaction.sa_flags into a user 966 // provided buffer. Returns that buffer. 967 const char* os::Posix::describe_sa_flags(int flags, char* buffer, size_t size) { 968 char* p = buffer; 969 size_t remaining = size; 970 bool first = true; 971 int idx = 0; 972 973 assert(buffer, "invalid argument"); 974 975 if (size == 0) { 976 return buffer; 977 } 978 979 strncpy(buffer, "none", size); 980 981 const struct { 982 // NB: i is an unsigned int here because SA_RESETHAND is on some 983 // systems 0x80000000, which is implicitly unsigned. Assignining 984 // it to an int field would be an overflow in unsigned-to-signed 985 // conversion. 986 unsigned int i; 987 const char* s; 988 } flaginfo [] = { 989 { SA_NOCLDSTOP, "SA_NOCLDSTOP" }, 990 { SA_ONSTACK, "SA_ONSTACK" }, 991 { SA_RESETHAND, "SA_RESETHAND" }, 992 { SA_RESTART, "SA_RESTART" }, 993 { SA_SIGINFO, "SA_SIGINFO" }, 994 { SA_NOCLDWAIT, "SA_NOCLDWAIT" }, 995 { SA_NODEFER, "SA_NODEFER" }, 996 #ifdef AIX 997 { SA_ONSTACK, "SA_ONSTACK" }, 998 { SA_OLDSTYLE, "SA_OLDSTYLE" }, 999 #endif 1000 { 0, NULL } 1001 }; 1002 1003 for (idx = 0; flaginfo[idx].s && remaining > 1; idx++) { 1004 if (flags & flaginfo[idx].i) { 1005 if (first) { 1006 jio_snprintf(p, remaining, "%s", flaginfo[idx].s); 1007 first = false; 1008 } else { 1009 jio_snprintf(p, remaining, "|%s", flaginfo[idx].s); 1010 } 1011 const size_t len = strlen(p); 1012 p += len; 1013 remaining -= len; 1014 } 1015 } 1016 1017 buffer[size - 1] = '\0'; 1018 1019 return buffer; 1020 } 1021 1022 // Prints one-line description of a combination of sigaction.sa_flags. 1023 void os::Posix::print_sa_flags(outputStream* st, int flags) { 1024 char buffer[0x100]; 1025 os::Posix::describe_sa_flags(flags, buffer, sizeof(buffer)); 1026 st->print("%s", buffer); 1027 } 1028 1029 // Helper function for os::Posix::print_siginfo_...(): 1030 // return a textual description for signal code. 1031 struct enum_sigcode_desc_t { 1032 const char* s_name; 1033 const char* s_desc; 1034 }; 1035 1036 static bool get_signal_code_description(const siginfo_t* si, enum_sigcode_desc_t* out) { 1037 1038 const struct { 1039 int sig; int code; const char* s_code; const char* s_desc; 1040 } t1 [] = { 1041 { SIGILL, ILL_ILLOPC, "ILL_ILLOPC", "Illegal opcode." }, 1042 { SIGILL, ILL_ILLOPN, "ILL_ILLOPN", "Illegal operand." }, 1043 { SIGILL, ILL_ILLADR, "ILL_ILLADR", "Illegal addressing mode." }, 1044 { SIGILL, ILL_ILLTRP, "ILL_ILLTRP", "Illegal trap." }, 1045 { SIGILL, ILL_PRVOPC, "ILL_PRVOPC", "Privileged opcode." }, 1046 { SIGILL, ILL_PRVREG, "ILL_PRVREG", "Privileged register." }, 1047 { SIGILL, ILL_COPROC, "ILL_COPROC", "Coprocessor error." }, 1048 { SIGILL, ILL_BADSTK, "ILL_BADSTK", "Internal stack error." }, 1049 #if defined(IA64) && defined(LINUX) 1050 { SIGILL, ILL_BADIADDR, "ILL_BADIADDR", "Unimplemented instruction address" }, 1051 { SIGILL, ILL_BREAK, "ILL_BREAK", "Application Break instruction" }, 1052 #endif 1053 { SIGFPE, FPE_INTDIV, "FPE_INTDIV", "Integer divide by zero." }, 1054 { SIGFPE, FPE_INTOVF, "FPE_INTOVF", "Integer overflow." }, 1055 { SIGFPE, FPE_FLTDIV, "FPE_FLTDIV", "Floating-point divide by zero." }, 1056 { SIGFPE, FPE_FLTOVF, "FPE_FLTOVF", "Floating-point overflow." }, 1057 { SIGFPE, FPE_FLTUND, "FPE_FLTUND", "Floating-point underflow." }, 1058 { SIGFPE, FPE_FLTRES, "FPE_FLTRES", "Floating-point inexact result." }, 1059 { SIGFPE, FPE_FLTINV, "FPE_FLTINV", "Invalid floating-point operation." }, 1060 { SIGFPE, FPE_FLTSUB, "FPE_FLTSUB", "Subscript out of range." }, 1061 { SIGSEGV, SEGV_MAPERR, "SEGV_MAPERR", "Address not mapped to object." }, 1062 { SIGSEGV, SEGV_ACCERR, "SEGV_ACCERR", "Invalid permissions for mapped object." }, 1063 #ifdef AIX 1064 // no explanation found what keyerr would be 1065 { SIGSEGV, SEGV_KEYERR, "SEGV_KEYERR", "key error" }, 1066 #endif 1067 #if defined(IA64) && !defined(AIX) 1068 { SIGSEGV, SEGV_PSTKOVF, "SEGV_PSTKOVF", "Paragraph stack overflow" }, 1069 #endif 1070 #if defined(__sparc) && defined(SOLARIS) 1071 // define Solaris Sparc M7 ADI SEGV signals 1072 #if !defined(SEGV_ACCADI) 1073 #define SEGV_ACCADI 3 1074 #endif 1075 { SIGSEGV, SEGV_ACCADI, "SEGV_ACCADI", "ADI not enabled for mapped object." }, 1076 #if !defined(SEGV_ACCDERR) 1077 #define SEGV_ACCDERR 4 1078 #endif 1079 { SIGSEGV, SEGV_ACCDERR, "SEGV_ACCDERR", "ADI disrupting exception." }, 1080 #if !defined(SEGV_ACCPERR) 1081 #define SEGV_ACCPERR 5 1082 #endif 1083 { SIGSEGV, SEGV_ACCPERR, "SEGV_ACCPERR", "ADI precise exception." }, 1084 #endif // defined(__sparc) && defined(SOLARIS) 1085 { SIGBUS, BUS_ADRALN, "BUS_ADRALN", "Invalid address alignment." }, 1086 { SIGBUS, BUS_ADRERR, "BUS_ADRERR", "Nonexistent physical address." }, 1087 { SIGBUS, BUS_OBJERR, "BUS_OBJERR", "Object-specific hardware error." }, 1088 { SIGTRAP, TRAP_BRKPT, "TRAP_BRKPT", "Process breakpoint." }, 1089 { SIGTRAP, TRAP_TRACE, "TRAP_TRACE", "Process trace trap." }, 1090 { SIGCHLD, CLD_EXITED, "CLD_EXITED", "Child has exited." }, 1091 { SIGCHLD, CLD_KILLED, "CLD_KILLED", "Child has terminated abnormally and did not create a core file." }, 1092 { SIGCHLD, CLD_DUMPED, "CLD_DUMPED", "Child has terminated abnormally and created a core file." }, 1093 { SIGCHLD, CLD_TRAPPED, "CLD_TRAPPED", "Traced child has trapped." }, 1094 { SIGCHLD, CLD_STOPPED, "CLD_STOPPED", "Child has stopped." }, 1095 { SIGCHLD, CLD_CONTINUED,"CLD_CONTINUED","Stopped child has continued." }, 1096 #ifdef SIGPOLL 1097 { SIGPOLL, POLL_OUT, "POLL_OUT", "Output buffers available." }, 1098 { SIGPOLL, POLL_MSG, "POLL_MSG", "Input message available." }, 1099 { SIGPOLL, POLL_ERR, "POLL_ERR", "I/O error." }, 1100 { SIGPOLL, POLL_PRI, "POLL_PRI", "High priority input available." }, 1101 { SIGPOLL, POLL_HUP, "POLL_HUP", "Device disconnected. [Option End]" }, 1102 #endif 1103 { -1, -1, NULL, NULL } 1104 }; 1105 1106 // Codes valid in any signal context. 1107 const struct { 1108 int code; const char* s_code; const char* s_desc; 1109 } t2 [] = { 1110 { SI_USER, "SI_USER", "Signal sent by kill()." }, 1111 { SI_QUEUE, "SI_QUEUE", "Signal sent by the sigqueue()." }, 1112 { SI_TIMER, "SI_TIMER", "Signal generated by expiration of a timer set by timer_settime()." }, 1113 { SI_ASYNCIO, "SI_ASYNCIO", "Signal generated by completion of an asynchronous I/O request." }, 1114 { SI_MESGQ, "SI_MESGQ", "Signal generated by arrival of a message on an empty message queue." }, 1115 // Linux specific 1116 #ifdef SI_TKILL 1117 { SI_TKILL, "SI_TKILL", "Signal sent by tkill (pthread_kill)" }, 1118 #endif 1119 #ifdef SI_DETHREAD 1120 { SI_DETHREAD, "SI_DETHREAD", "Signal sent by execve() killing subsidiary threads" }, 1121 #endif 1122 #ifdef SI_KERNEL 1123 { SI_KERNEL, "SI_KERNEL", "Signal sent by kernel." }, 1124 #endif 1125 #ifdef SI_SIGIO 1126 { SI_SIGIO, "SI_SIGIO", "Signal sent by queued SIGIO" }, 1127 #endif 1128 1129 #ifdef AIX 1130 { SI_UNDEFINED, "SI_UNDEFINED","siginfo contains partial information" }, 1131 { SI_EMPTY, "SI_EMPTY", "siginfo contains no useful information" }, 1132 #endif 1133 1134 #ifdef __sun 1135 { SI_NOINFO, "SI_NOINFO", "No signal information" }, 1136 { SI_RCTL, "SI_RCTL", "kernel generated signal via rctl action" }, 1137 { SI_LWP, "SI_LWP", "Signal sent via lwp_kill" }, 1138 #endif 1139 1140 { -1, NULL, NULL } 1141 }; 1142 1143 const char* s_code = NULL; 1144 const char* s_desc = NULL; 1145 1146 for (int i = 0; t1[i].sig != -1; i ++) { 1147 if (t1[i].sig == si->si_signo && t1[i].code == si->si_code) { 1148 s_code = t1[i].s_code; 1149 s_desc = t1[i].s_desc; 1150 break; 1151 } 1152 } 1153 1154 if (s_code == NULL) { 1155 for (int i = 0; t2[i].s_code != NULL; i ++) { 1156 if (t2[i].code == si->si_code) { 1157 s_code = t2[i].s_code; 1158 s_desc = t2[i].s_desc; 1159 } 1160 } 1161 } 1162 1163 if (s_code == NULL) { 1164 out->s_name = "unknown"; 1165 out->s_desc = "unknown"; 1166 return false; 1167 } 1168 1169 out->s_name = s_code; 1170 out->s_desc = s_desc; 1171 1172 return true; 1173 } 1174 1175 void os::print_siginfo(outputStream* os, const void* si0) { 1176 1177 const siginfo_t* const si = (const siginfo_t*) si0; 1178 1179 char buf[20]; 1180 os->print("siginfo:"); 1181 1182 if (!si) { 1183 os->print(" <null>"); 1184 return; 1185 } 1186 1187 const int sig = si->si_signo; 1188 1189 os->print(" si_signo: %d (%s)", sig, os::Posix::get_signal_name(sig, buf, sizeof(buf))); 1190 1191 enum_sigcode_desc_t ed; 1192 get_signal_code_description(si, &ed); 1193 os->print(", si_code: %d (%s)", si->si_code, ed.s_name); 1194 1195 if (si->si_errno) { 1196 os->print(", si_errno: %d", si->si_errno); 1197 } 1198 1199 // Output additional information depending on the signal code. 1200 1201 // Note: Many implementations lump si_addr, si_pid, si_uid etc. together as unions, 1202 // so it depends on the context which member to use. For synchronous error signals, 1203 // we print si_addr, unless the signal was sent by another process or thread, in 1204 // which case we print out pid or tid of the sender. 1205 if (si->si_code == SI_USER || si->si_code == SI_QUEUE) { 1206 const pid_t pid = si->si_pid; 1207 os->print(", si_pid: %ld", (long) pid); 1208 if (IS_VALID_PID(pid)) { 1209 const pid_t me = getpid(); 1210 if (me == pid) { 1211 os->print(" (current process)"); 1212 } 1213 } else { 1214 os->print(" (invalid)"); 1215 } 1216 os->print(", si_uid: %ld", (long) si->si_uid); 1217 if (sig == SIGCHLD) { 1218 os->print(", si_status: %d", si->si_status); 1219 } 1220 } else if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL || 1221 sig == SIGTRAP || sig == SIGFPE) { 1222 os->print(", si_addr: " PTR_FORMAT, p2i(si->si_addr)); 1223 #ifdef SIGPOLL 1224 } else if (sig == SIGPOLL) { 1225 os->print(", si_band: %ld", si->si_band); 1226 #endif 1227 } 1228 1229 } 1230 1231 int os::Posix::unblock_thread_signal_mask(const sigset_t *set) { 1232 return pthread_sigmask(SIG_UNBLOCK, set, NULL); 1233 } 1234 1235 address os::Posix::ucontext_get_pc(const ucontext_t* ctx) { 1236 #if defined(AIX) 1237 return Aix::ucontext_get_pc(ctx); 1238 #elif defined(BSD) 1239 return Bsd::ucontext_get_pc(ctx); 1240 #elif defined(LINUX) 1241 return Linux::ucontext_get_pc(ctx); 1242 #elif defined(SOLARIS) 1243 return Solaris::ucontext_get_pc(ctx); 1244 #else 1245 VMError::report_and_die("unimplemented ucontext_get_pc"); 1246 #endif 1247 } 1248 1249 void os::Posix::ucontext_set_pc(ucontext_t* ctx, address pc) { 1250 #if defined(AIX) 1251 Aix::ucontext_set_pc(ctx, pc); 1252 #elif defined(BSD) 1253 Bsd::ucontext_set_pc(ctx, pc); 1254 #elif defined(LINUX) 1255 Linux::ucontext_set_pc(ctx, pc); 1256 #elif defined(SOLARIS) 1257 Solaris::ucontext_set_pc(ctx, pc); 1258 #else 1259 VMError::report_and_die("unimplemented ucontext_get_pc"); 1260 #endif 1261 } 1262 1263 char* os::Posix::describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr) { 1264 size_t stack_size = 0; 1265 size_t guard_size = 0; 1266 int detachstate = 0; 1267 pthread_attr_getstacksize(attr, &stack_size); 1268 pthread_attr_getguardsize(attr, &guard_size); 1269 // Work around linux NPTL implementation error, see also os::create_thread() in os_linux.cpp. 1270 LINUX_ONLY(stack_size -= guard_size); 1271 pthread_attr_getdetachstate(attr, &detachstate); 1272 jio_snprintf(buf, buflen, "stacksize: " SIZE_FORMAT "k, guardsize: " SIZE_FORMAT "k, %s", 1273 stack_size / 1024, guard_size / 1024, 1274 (detachstate == PTHREAD_CREATE_DETACHED ? "detached" : "joinable")); 1275 return buf; 1276 } 1277 1278 char* os::Posix::realpath(const char* filename, char* outbuf, size_t outbuflen) { 1279 1280 if (filename == NULL || outbuf == NULL || outbuflen < 1) { 1281 assert(false, "os::Posix::realpath: invalid arguments."); 1282 errno = EINVAL; 1283 return NULL; 1284 } 1285 1286 char* result = NULL; 1287 1288 // This assumes platform realpath() is implemented according to POSIX.1-2008. 1289 // POSIX.1-2008 allows to specify NULL for the output buffer, in which case 1290 // output buffer is dynamically allocated and must be ::free()'d by the caller. 1291 char* p = ::realpath(filename, NULL); 1292 if (p != NULL) { 1293 if (strlen(p) < outbuflen) { 1294 strcpy(outbuf, p); 1295 result = outbuf; 1296 } else { 1297 errno = ENAMETOOLONG; 1298 } 1299 ::free(p); // *not* os::free 1300 } else { 1301 // Fallback for platforms struggling with modern Posix standards (AIX 5.3, 6.1). If realpath 1302 // returns EINVAL, this may indicate that realpath is not POSIX.1-2008 compatible and 1303 // that it complains about the NULL we handed down as user buffer. 1304 // In this case, use the user provided buffer but at least check whether realpath caused 1305 // a memory overwrite. 1306 if (errno == EINVAL) { 1307 outbuf[outbuflen - 1] = '\0'; 1308 p = ::realpath(filename, outbuf); 1309 if (p != NULL) { 1310 guarantee(outbuf[outbuflen - 1] == '\0', "realpath buffer overwrite detected."); 1311 result = p; 1312 } 1313 } 1314 } 1315 return result; 1316 1317 } 1318 1319 1320 // Check minimum allowable stack sizes for thread creation and to initialize 1321 // the java system classes, including StackOverflowError - depends on page 1322 // size. 1323 // The space needed for frames during startup is platform dependent. It 1324 // depends on word size, platform calling conventions, C frame layout and 1325 // interpreter/C1/C2 design decisions. Therefore this is given in a 1326 // platform (os/cpu) dependent constant. 1327 // To this, space for guard mechanisms is added, which depends on the 1328 // page size which again depends on the concrete system the VM is running 1329 // on. Space for libc guard pages is not included in this size. 1330 jint os::Posix::set_minimum_stack_sizes() { 1331 size_t os_min_stack_allowed = SOLARIS_ONLY(thr_min_stack()) NOT_SOLARIS(PTHREAD_STACK_MIN); 1332 1333 _java_thread_min_stack_allowed = _java_thread_min_stack_allowed + 1334 JavaThread::stack_guard_zone_size() + 1335 JavaThread::stack_shadow_zone_size(); 1336 1337 _java_thread_min_stack_allowed = align_up(_java_thread_min_stack_allowed, vm_page_size()); 1338 _java_thread_min_stack_allowed = MAX2(_java_thread_min_stack_allowed, os_min_stack_allowed); 1339 1340 size_t stack_size_in_bytes = ThreadStackSize * K; 1341 if (stack_size_in_bytes != 0 && 1342 stack_size_in_bytes < _java_thread_min_stack_allowed) { 1343 // The '-Xss' and '-XX:ThreadStackSize=N' options both set 1344 // ThreadStackSize so we go with "Java thread stack size" instead 1345 // of "ThreadStackSize" to be more friendly. 1346 tty->print_cr("\nThe Java thread stack size specified is too small. " 1347 "Specify at least " SIZE_FORMAT "k", 1348 _java_thread_min_stack_allowed / K); 1349 return JNI_ERR; 1350 } 1351 1352 // Make the stack size a multiple of the page size so that 1353 // the yellow/red zones can be guarded. 1354 JavaThread::set_stack_size_at_create(align_up(stack_size_in_bytes, vm_page_size())); 1355 1356 // Reminder: a compiler thread is a Java thread. 1357 _compiler_thread_min_stack_allowed = _compiler_thread_min_stack_allowed + 1358 JavaThread::stack_guard_zone_size() + 1359 JavaThread::stack_shadow_zone_size(); 1360 1361 _compiler_thread_min_stack_allowed = align_up(_compiler_thread_min_stack_allowed, vm_page_size()); 1362 _compiler_thread_min_stack_allowed = MAX2(_compiler_thread_min_stack_allowed, os_min_stack_allowed); 1363 1364 stack_size_in_bytes = CompilerThreadStackSize * K; 1365 if (stack_size_in_bytes != 0 && 1366 stack_size_in_bytes < _compiler_thread_min_stack_allowed) { 1367 tty->print_cr("\nThe CompilerThreadStackSize specified is too small. " 1368 "Specify at least " SIZE_FORMAT "k", 1369 _compiler_thread_min_stack_allowed / K); 1370 return JNI_ERR; 1371 } 1372 1373 _vm_internal_thread_min_stack_allowed = align_up(_vm_internal_thread_min_stack_allowed, vm_page_size()); 1374 _vm_internal_thread_min_stack_allowed = MAX2(_vm_internal_thread_min_stack_allowed, os_min_stack_allowed); 1375 1376 stack_size_in_bytes = VMThreadStackSize * K; 1377 if (stack_size_in_bytes != 0 && 1378 stack_size_in_bytes < _vm_internal_thread_min_stack_allowed) { 1379 tty->print_cr("\nThe VMThreadStackSize specified is too small. " 1380 "Specify at least " SIZE_FORMAT "k", 1381 _vm_internal_thread_min_stack_allowed / K); 1382 return JNI_ERR; 1383 } 1384 return JNI_OK; 1385 } 1386 1387 // Called when creating the thread. The minimum stack sizes have already been calculated 1388 size_t os::Posix::get_initial_stack_size(ThreadType thr_type, size_t req_stack_size) { 1389 size_t stack_size; 1390 if (req_stack_size == 0) { 1391 stack_size = default_stack_size(thr_type); 1392 } else { 1393 stack_size = req_stack_size; 1394 } 1395 1396 switch (thr_type) { 1397 case os::java_thread: 1398 // Java threads use ThreadStackSize which default value can be 1399 // changed with the flag -Xss 1400 if (req_stack_size == 0 && JavaThread::stack_size_at_create() > 0) { 1401 // no requested size and we have a more specific default value 1402 stack_size = JavaThread::stack_size_at_create(); 1403 } 1404 stack_size = MAX2(stack_size, 1405 _java_thread_min_stack_allowed); 1406 break; 1407 case os::compiler_thread: 1408 if (req_stack_size == 0 && CompilerThreadStackSize > 0) { 1409 // no requested size and we have a more specific default value 1410 stack_size = (size_t)(CompilerThreadStackSize * K); 1411 } 1412 stack_size = MAX2(stack_size, 1413 _compiler_thread_min_stack_allowed); 1414 break; 1415 case os::vm_thread: 1416 case os::pgc_thread: 1417 case os::cgc_thread: 1418 case os::watcher_thread: 1419 default: // presume the unknown thr_type is a VM internal 1420 if (req_stack_size == 0 && VMThreadStackSize > 0) { 1421 // no requested size and we have a more specific default value 1422 stack_size = (size_t)(VMThreadStackSize * K); 1423 } 1424 1425 stack_size = MAX2(stack_size, 1426 _vm_internal_thread_min_stack_allowed); 1427 break; 1428 } 1429 1430 // pthread_attr_setstacksize() may require that the size be rounded up to the OS page size. 1431 // Be careful not to round up to 0. Align down in that case. 1432 if (stack_size <= SIZE_MAX - vm_page_size()) { 1433 stack_size = align_up(stack_size, vm_page_size()); 1434 } else { 1435 stack_size = align_down(stack_size, vm_page_size()); 1436 } 1437 1438 return stack_size; 1439 } 1440 1441 Thread* os::ThreadCrashProtection::_protected_thread = NULL; 1442 os::ThreadCrashProtection* os::ThreadCrashProtection::_crash_protection = NULL; 1443 volatile intptr_t os::ThreadCrashProtection::_crash_mux = 0; 1444 1445 os::ThreadCrashProtection::ThreadCrashProtection() { 1446 } 1447 1448 /* 1449 * See the caveats for this class in os_posix.hpp 1450 * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this 1451 * method and returns false. If none of the signals are raised, returns true. 1452 * The callback is supposed to provide the method that should be protected. 1453 */ 1454 bool os::ThreadCrashProtection::call(os::CrashProtectionCallback& cb) { 1455 sigset_t saved_sig_mask; 1456 1457 Thread::muxAcquire(&_crash_mux, "CrashProtection"); 1458 1459 _protected_thread = Thread::current_or_null(); 1460 assert(_protected_thread != NULL, "Cannot crash protect a NULL thread"); 1461 1462 // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask 1463 // since on at least some systems (OS X) siglongjmp will restore the mask 1464 // for the process, not the thread 1465 pthread_sigmask(0, NULL, &saved_sig_mask); 1466 if (sigsetjmp(_jmpbuf, 0) == 0) { 1467 // make sure we can see in the signal handler that we have crash protection 1468 // installed 1469 _crash_protection = this; 1470 cb.call(); 1471 // and clear the crash protection 1472 _crash_protection = NULL; 1473 _protected_thread = NULL; 1474 Thread::muxRelease(&_crash_mux); 1475 return true; 1476 } 1477 // this happens when we siglongjmp() back 1478 pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL); 1479 _crash_protection = NULL; 1480 _protected_thread = NULL; 1481 Thread::muxRelease(&_crash_mux); 1482 return false; 1483 } 1484 1485 void os::ThreadCrashProtection::restore() { 1486 assert(_crash_protection != NULL, "must have crash protection"); 1487 siglongjmp(_jmpbuf, 1); 1488 } 1489 1490 void os::ThreadCrashProtection::check_crash_protection(int sig, 1491 Thread* thread) { 1492 1493 if (thread != NULL && 1494 thread == _protected_thread && 1495 _crash_protection != NULL) { 1496 1497 if (sig == SIGSEGV || sig == SIGBUS) { 1498 _crash_protection->restore(); 1499 } 1500 } 1501 } 1502 1503 // POSIX unamed semaphores are not supported on OS X. 1504 #ifndef __APPLE__ 1505 1506 PosixSemaphore::PosixSemaphore(uint value) { 1507 int ret = sem_init(&_semaphore, 0, value); 1508 1509 guarantee_with_errno(ret == 0, "Failed to initialize semaphore"); 1510 } 1511 1512 PosixSemaphore::~PosixSemaphore() { 1513 sem_destroy(&_semaphore); 1514 } 1515 1516 void PosixSemaphore::signal(uint count) { 1517 for (uint i = 0; i < count; i++) { 1518 int ret = sem_post(&_semaphore); 1519 1520 assert_with_errno(ret == 0, "sem_post failed"); 1521 } 1522 } 1523 1524 void PosixSemaphore::wait() { 1525 int ret; 1526 1527 do { 1528 ret = sem_wait(&_semaphore); 1529 } while (ret != 0 && errno == EINTR); 1530 1531 assert_with_errno(ret == 0, "sem_wait failed"); 1532 } 1533 1534 bool PosixSemaphore::trywait() { 1535 int ret; 1536 1537 do { 1538 ret = sem_trywait(&_semaphore); 1539 } while (ret != 0 && errno == EINTR); 1540 1541 assert_with_errno(ret == 0 || errno == EAGAIN, "trywait failed"); 1542 1543 return ret == 0; 1544 } 1545 1546 bool PosixSemaphore::timedwait(struct timespec ts) { 1547 while (true) { 1548 int result = sem_timedwait(&_semaphore, &ts); 1549 if (result == 0) { 1550 return true; 1551 } else if (errno == EINTR) { 1552 continue; 1553 } else if (errno == ETIMEDOUT) { 1554 return false; 1555 } else { 1556 assert_with_errno(false, "timedwait failed"); 1557 return false; 1558 } 1559 } 1560 } 1561 1562 #endif // __APPLE__ 1563 1564 1565 // Shared pthread_mutex/cond based PlatformEvent implementation. 1566 // Not currently usable by Solaris. 1567 1568 #ifndef SOLARIS 1569 1570 // Shared condattr object for use with relative timed-waits. Will be associated 1571 // with CLOCK_MONOTONIC if available to avoid issues with time-of-day changes, 1572 // but otherwise whatever default is used by the platform - generally the 1573 // time-of-day clock. 1574 static pthread_condattr_t _condAttr[1]; 1575 1576 // Shared mutexattr to explicitly set the type to PTHREAD_MUTEX_NORMAL as not 1577 // all systems (e.g. FreeBSD) map the default to "normal". 1578 static pthread_mutexattr_t _mutexAttr[1]; 1579 1580 // common basic initialization that is always supported 1581 static void pthread_init_common(void) { 1582 int status; 1583 if ((status = pthread_condattr_init(_condAttr)) != 0) { 1584 fatal("pthread_condattr_init: %s", os::strerror(status)); 1585 } 1586 if ((status = pthread_mutexattr_init(_mutexAttr)) != 0) { 1587 fatal("pthread_mutexattr_init: %s", os::strerror(status)); 1588 } 1589 if ((status = pthread_mutexattr_settype(_mutexAttr, PTHREAD_MUTEX_NORMAL)) != 0) { 1590 fatal("pthread_mutexattr_settype: %s", os::strerror(status)); 1591 } 1592 } 1593 1594 // Not all POSIX types and API's are available on all notionally "posix" 1595 // platforms. If we have build-time support then we will check for actual 1596 // runtime support via dlopen/dlsym lookup. This allows for running on an 1597 // older OS version compared to the build platform. But if there is no 1598 // build time support then there cannot be any runtime support as we do not 1599 // know what the runtime types would be (for example clockid_t might be an 1600 // int or int64_t). 1601 // 1602 #ifdef SUPPORTS_CLOCK_MONOTONIC 1603 1604 // This means we have clockid_t, clock_gettime et al and CLOCK_MONOTONIC 1605 1606 static int (*_clock_gettime)(clockid_t, struct timespec *); 1607 static int (*_pthread_condattr_setclock)(pthread_condattr_t *, clockid_t); 1608 1609 static bool _use_clock_monotonic_condattr; 1610 1611 // Determine what POSIX API's are present and do appropriate 1612 // configuration. 1613 void os::Posix::init(void) { 1614 1615 // NOTE: no logging available when this is called. Put logging 1616 // statements in init_2(). 1617 1618 // Copied from os::Linux::clock_init(). The duplication is temporary. 1619 1620 // 1. Check for CLOCK_MONOTONIC support. 1621 1622 void* handle = NULL; 1623 1624 // For linux we need librt, for other OS we can find 1625 // this function in regular libc. 1626 #ifdef NEEDS_LIBRT 1627 // We do dlopen's in this particular order due to bug in linux 1628 // dynamic loader (see 6348968) leading to crash on exit. 1629 handle = dlopen("librt.so.1", RTLD_LAZY); 1630 if (handle == NULL) { 1631 handle = dlopen("librt.so", RTLD_LAZY); 1632 } 1633 #endif 1634 1635 if (handle == NULL) { 1636 handle = RTLD_DEFAULT; 1637 } 1638 1639 _clock_gettime = NULL; 1640 1641 int (*clock_getres_func)(clockid_t, struct timespec*) = 1642 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1643 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1644 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1645 if (clock_getres_func != NULL && clock_gettime_func != NULL) { 1646 // We assume that if both clock_gettime and clock_getres support 1647 // CLOCK_MONOTONIC then the OS provides true high-res monotonic clock. 1648 struct timespec res; 1649 struct timespec tp; 1650 if (clock_getres_func(CLOCK_MONOTONIC, &res) == 0 && 1651 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1652 // Yes, monotonic clock is supported. 1653 _clock_gettime = clock_gettime_func; 1654 } else { 1655 #ifdef NEEDS_LIBRT 1656 // Close librt if there is no monotonic clock. 1657 if (handle != RTLD_DEFAULT) { 1658 dlclose(handle); 1659 } 1660 #endif 1661 } 1662 } 1663 1664 // 2. Check for pthread_condattr_setclock support. 1665 1666 _pthread_condattr_setclock = NULL; 1667 1668 // libpthread is already loaded. 1669 int (*condattr_setclock_func)(pthread_condattr_t*, clockid_t) = 1670 (int (*)(pthread_condattr_t*, clockid_t))dlsym(RTLD_DEFAULT, 1671 "pthread_condattr_setclock"); 1672 if (condattr_setclock_func != NULL) { 1673 _pthread_condattr_setclock = condattr_setclock_func; 1674 } 1675 1676 // Now do general initialization. 1677 1678 pthread_init_common(); 1679 1680 int status; 1681 if (_pthread_condattr_setclock != NULL && _clock_gettime != NULL) { 1682 if ((status = _pthread_condattr_setclock(_condAttr, CLOCK_MONOTONIC)) != 0) { 1683 if (status == EINVAL) { 1684 _use_clock_monotonic_condattr = false; 1685 warning("Unable to use monotonic clock with relative timed-waits" \ 1686 " - changes to the time-of-day clock may have adverse affects"); 1687 } else { 1688 fatal("pthread_condattr_setclock: %s", os::strerror(status)); 1689 } 1690 } else { 1691 _use_clock_monotonic_condattr = true; 1692 } 1693 } else { 1694 _use_clock_monotonic_condattr = false; 1695 } 1696 } 1697 1698 void os::Posix::init_2(void) { 1699 log_info(os)("Use of CLOCK_MONOTONIC is%s supported", 1700 (_clock_gettime != NULL ? "" : " not")); 1701 log_info(os)("Use of pthread_condattr_setclock is%s supported", 1702 (_pthread_condattr_setclock != NULL ? "" : " not")); 1703 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with %s", 1704 _use_clock_monotonic_condattr ? "CLOCK_MONOTONIC" : "the default clock"); 1705 } 1706 1707 #else // !SUPPORTS_CLOCK_MONOTONIC 1708 1709 void os::Posix::init(void) { 1710 pthread_init_common(); 1711 } 1712 1713 void os::Posix::init_2(void) { 1714 log_info(os)("Use of CLOCK_MONOTONIC is not supported"); 1715 log_info(os)("Use of pthread_condattr_setclock is not supported"); 1716 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with the default clock"); 1717 } 1718 1719 #endif // SUPPORTS_CLOCK_MONOTONIC 1720 1721 os::PlatformEvent::PlatformEvent() { 1722 int status = pthread_cond_init(_cond, _condAttr); 1723 assert_status(status == 0, status, "cond_init"); 1724 status = pthread_mutex_init(_mutex, _mutexAttr); 1725 assert_status(status == 0, status, "mutex_init"); 1726 _event = 0; 1727 _nParked = 0; 1728 } 1729 1730 // Utility to convert the given timeout to an absolute timespec 1731 // (based on the appropriate clock) to use with pthread_cond_timewait. 1732 // The clock queried here must be the clock used to manage the 1733 // timeout of the condition variable. 1734 // 1735 // The passed in timeout value is either a relative time in nanoseconds 1736 // or an absolute time in milliseconds. A relative timeout will be 1737 // associated with CLOCK_MONOTONIC if available; otherwise, or if absolute, 1738 // the default time-of-day clock will be used. 1739 1740 // Given time is a 64-bit value and the time_t used in the timespec is 1741 // sometimes a signed-32-bit value we have to watch for overflow if times 1742 // way in the future are given. Further on Solaris versions 1743 // prior to 10 there is a restriction (see cond_timedwait) that the specified 1744 // number of seconds, in abstime, is less than current_time + 100000000. 1745 // As it will be over 20 years before "now + 100000000" will overflow we can 1746 // ignore overflow and just impose a hard-limit on seconds using the value 1747 // of "now + 100000000". This places a limit on the timeout of about 3.17 1748 // years from "now". 1749 // 1750 #define MAX_SECS 100000000 1751 1752 // Calculate a new absolute time that is "timeout" nanoseconds from "now". 1753 // "unit" indicates the unit of "now_part_sec" (may be nanos or micros depending 1754 // on which clock is being used). 1755 static void calc_rel_time(timespec* abstime, jlong timeout, jlong now_sec, 1756 jlong now_part_sec, jlong unit) { 1757 time_t max_secs = now_sec + MAX_SECS; 1758 1759 jlong seconds = timeout / NANOUNITS; 1760 timeout %= NANOUNITS; // remaining nanos 1761 1762 if (seconds >= MAX_SECS) { 1763 // More seconds than we can add, so pin to max_secs. 1764 abstime->tv_sec = max_secs; 1765 abstime->tv_nsec = 0; 1766 } else { 1767 abstime->tv_sec = now_sec + seconds; 1768 long nanos = (now_part_sec * (NANOUNITS / unit)) + timeout; 1769 if (nanos >= NANOUNITS) { // overflow 1770 abstime->tv_sec += 1; 1771 nanos -= NANOUNITS; 1772 } 1773 abstime->tv_nsec = nanos; 1774 } 1775 } 1776 1777 // Unpack the given deadline in milliseconds since the epoch, into the given timespec. 1778 // The current time in seconds is also passed in to enforce an upper bound as discussed above. 1779 static void unpack_abs_time(timespec* abstime, jlong deadline, jlong now_sec) { 1780 time_t max_secs = now_sec + MAX_SECS; 1781 1782 jlong seconds = deadline / MILLIUNITS; 1783 jlong millis = deadline % MILLIUNITS; 1784 1785 if (seconds >= max_secs) { 1786 // Absolute seconds exceeds allowed max, so pin to max_secs. 1787 abstime->tv_sec = max_secs; 1788 abstime->tv_nsec = 0; 1789 } else { 1790 abstime->tv_sec = seconds; 1791 abstime->tv_nsec = millis * (NANOUNITS / MILLIUNITS); 1792 } 1793 } 1794 1795 static void to_abstime(timespec* abstime, jlong timeout, bool isAbsolute) { 1796 DEBUG_ONLY(int max_secs = MAX_SECS;) 1797 1798 if (timeout < 0) { 1799 timeout = 0; 1800 } 1801 1802 #ifdef SUPPORTS_CLOCK_MONOTONIC 1803 1804 if (_use_clock_monotonic_condattr && !isAbsolute) { 1805 struct timespec now; 1806 int status = _clock_gettime(CLOCK_MONOTONIC, &now); 1807 assert_status(status == 0, status, "clock_gettime"); 1808 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_nsec, NANOUNITS); 1809 DEBUG_ONLY(max_secs += now.tv_sec;) 1810 } else { 1811 1812 #else 1813 1814 { // Match the block scope. 1815 1816 #endif // SUPPORTS_CLOCK_MONOTONIC 1817 1818 // Time-of-day clock is all we can reliably use. 1819 struct timeval now; 1820 int status = gettimeofday(&now, NULL); 1821 assert_status(status == 0, errno, "gettimeofday"); 1822 if (isAbsolute) { 1823 unpack_abs_time(abstime, timeout, now.tv_sec); 1824 } else { 1825 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_usec, MICROUNITS); 1826 } 1827 DEBUG_ONLY(max_secs += now.tv_sec;) 1828 } 1829 1830 assert(abstime->tv_sec >= 0, "tv_sec < 0"); 1831 assert(abstime->tv_sec <= max_secs, "tv_sec > max_secs"); 1832 assert(abstime->tv_nsec >= 0, "tv_nsec < 0"); 1833 assert(abstime->tv_nsec < NANOUNITS, "tv_nsec >= NANOUNITS"); 1834 } 1835 1836 // PlatformEvent 1837 // 1838 // Assumption: 1839 // Only one parker can exist on an event, which is why we allocate 1840 // them per-thread. Multiple unparkers can coexist. 1841 // 1842 // _event serves as a restricted-range semaphore. 1843 // -1 : thread is blocked, i.e. there is a waiter 1844 // 0 : neutral: thread is running or ready, 1845 // could have been signaled after a wait started 1846 // 1 : signaled - thread is running or ready 1847 // 1848 // Having three states allows for some detection of bad usage - see 1849 // comments on unpark(). 1850 1851 void os::PlatformEvent::park() { // AKA "down()" 1852 // Transitions for _event: 1853 // -1 => -1 : illegal 1854 // 1 => 0 : pass - return immediately 1855 // 0 => -1 : block; then set _event to 0 before returning 1856 1857 // Invariant: Only the thread associated with the PlatformEvent 1858 // may call park(). 1859 assert(_nParked == 0, "invariant"); 1860 1861 int v; 1862 1863 // atomically decrement _event 1864 for (;;) { 1865 v = _event; 1866 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break; 1867 } 1868 guarantee(v >= 0, "invariant"); 1869 1870 if (v == 0) { // Do this the hard way by blocking ... 1871 int status = pthread_mutex_lock(_mutex); 1872 assert_status(status == 0, status, "mutex_lock"); 1873 guarantee(_nParked == 0, "invariant"); 1874 ++_nParked; 1875 while (_event < 0) { 1876 // OS-level "spurious wakeups" are ignored 1877 status = pthread_cond_wait(_cond, _mutex); 1878 assert_status(status == 0, status, "cond_wait"); 1879 } 1880 --_nParked; 1881 1882 _event = 0; 1883 status = pthread_mutex_unlock(_mutex); 1884 assert_status(status == 0, status, "mutex_unlock"); 1885 // Paranoia to ensure our locked and lock-free paths interact 1886 // correctly with each other. 1887 OrderAccess::fence(); 1888 } 1889 guarantee(_event >= 0, "invariant"); 1890 } 1891 1892 int os::PlatformEvent::park(jlong millis) { 1893 // Transitions for _event: 1894 // -1 => -1 : illegal 1895 // 1 => 0 : pass - return immediately 1896 // 0 => -1 : block; then set _event to 0 before returning 1897 1898 // Invariant: Only the thread associated with the Event/PlatformEvent 1899 // may call park(). 1900 assert(_nParked == 0, "invariant"); 1901 1902 int v; 1903 // atomically decrement _event 1904 for (;;) { 1905 v = _event; 1906 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break; 1907 } 1908 guarantee(v >= 0, "invariant"); 1909 1910 if (v == 0) { // Do this the hard way by blocking ... 1911 struct timespec abst; 1912 // We have to watch for overflow when converting millis to nanos, 1913 // but if millis is that large then we will end up limiting to 1914 // MAX_SECS anyway, so just do that here. 1915 if (millis / MILLIUNITS > MAX_SECS) { 1916 millis = jlong(MAX_SECS) * MILLIUNITS; 1917 } 1918 to_abstime(&abst, millis * (NANOUNITS / MILLIUNITS), false); 1919 1920 int ret = OS_TIMEOUT; 1921 int status = pthread_mutex_lock(_mutex); 1922 assert_status(status == 0, status, "mutex_lock"); 1923 guarantee(_nParked == 0, "invariant"); 1924 ++_nParked; 1925 1926 while (_event < 0) { 1927 status = pthread_cond_timedwait(_cond, _mutex, &abst); 1928 assert_status(status == 0 || status == ETIMEDOUT, 1929 status, "cond_timedwait"); 1930 // OS-level "spurious wakeups" are ignored unless the archaic 1931 // FilterSpuriousWakeups is set false. That flag should be obsoleted. 1932 if (!FilterSpuriousWakeups) break; 1933 if (status == ETIMEDOUT) break; 1934 } 1935 --_nParked; 1936 1937 if (_event >= 0) { 1938 ret = OS_OK; 1939 } 1940 1941 _event = 0; 1942 status = pthread_mutex_unlock(_mutex); 1943 assert_status(status == 0, status, "mutex_unlock"); 1944 // Paranoia to ensure our locked and lock-free paths interact 1945 // correctly with each other. 1946 OrderAccess::fence(); 1947 return ret; 1948 } 1949 return OS_OK; 1950 } 1951 1952 void os::PlatformEvent::unpark() { 1953 // Transitions for _event: 1954 // 0 => 1 : just return 1955 // 1 => 1 : just return 1956 // -1 => either 0 or 1; must signal target thread 1957 // That is, we can safely transition _event from -1 to either 1958 // 0 or 1. 1959 // See also: "Semaphores in Plan 9" by Mullender & Cox 1960 // 1961 // Note: Forcing a transition from "-1" to "1" on an unpark() means 1962 // that it will take two back-to-back park() calls for the owning 1963 // thread to block. This has the benefit of forcing a spurious return 1964 // from the first park() call after an unpark() call which will help 1965 // shake out uses of park() and unpark() without checking state conditions 1966 // properly. This spurious return doesn't manifest itself in any user code 1967 // but only in the correctly written condition checking loops of ObjectMonitor, 1968 // Mutex/Monitor, Thread::muxAcquire and os::sleep 1969 1970 if (Atomic::xchg(1, &_event) >= 0) return; 1971 1972 int status = pthread_mutex_lock(_mutex); 1973 assert_status(status == 0, status, "mutex_lock"); 1974 int anyWaiters = _nParked; 1975 assert(anyWaiters == 0 || anyWaiters == 1, "invariant"); 1976 status = pthread_mutex_unlock(_mutex); 1977 assert_status(status == 0, status, "mutex_unlock"); 1978 1979 // Note that we signal() *after* dropping the lock for "immortal" Events. 1980 // This is safe and avoids a common class of futile wakeups. In rare 1981 // circumstances this can cause a thread to return prematurely from 1982 // cond_{timed}wait() but the spurious wakeup is benign and the victim 1983 // will simply re-test the condition and re-park itself. 1984 // This provides particular benefit if the underlying platform does not 1985 // provide wait morphing. 1986 1987 if (anyWaiters != 0) { 1988 status = pthread_cond_signal(_cond); 1989 assert_status(status == 0, status, "cond_signal"); 1990 } 1991 } 1992 1993 // JSR166 support 1994 1995 os::PlatformParker::PlatformParker() { 1996 int status; 1997 status = pthread_cond_init(&_cond[REL_INDEX], _condAttr); 1998 assert_status(status == 0, status, "cond_init rel"); 1999 status = pthread_cond_init(&_cond[ABS_INDEX], NULL); 2000 assert_status(status == 0, status, "cond_init abs"); 2001 status = pthread_mutex_init(_mutex, _mutexAttr); 2002 assert_status(status == 0, status, "mutex_init"); 2003 _cur_index = -1; // mark as unused 2004 } 2005 2006 // Parker::park decrements count if > 0, else does a condvar wait. Unpark 2007 // sets count to 1 and signals condvar. Only one thread ever waits 2008 // on the condvar. Contention seen when trying to park implies that someone 2009 // is unparking you, so don't wait. And spurious returns are fine, so there 2010 // is no need to track notifications. 2011 2012 void Parker::park(bool isAbsolute, jlong time) { 2013 2014 // Optional fast-path check: 2015 // Return immediately if a permit is available. 2016 // We depend on Atomic::xchg() having full barrier semantics 2017 // since we are doing a lock-free update to _counter. 2018 if (Atomic::xchg(0, &_counter) > 0) return; 2019 2020 Thread* thread = Thread::current(); 2021 assert(thread->is_Java_thread(), "Must be JavaThread"); 2022 JavaThread *jt = (JavaThread *)thread; 2023 2024 // Optional optimization -- avoid state transitions if there's 2025 // an interrupt pending. 2026 if (Thread::is_interrupted(thread, false)) { 2027 return; 2028 } 2029 2030 // Next, demultiplex/decode time arguments 2031 struct timespec absTime; 2032 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all 2033 return; 2034 } 2035 if (time > 0) { 2036 to_abstime(&absTime, time, isAbsolute); 2037 } 2038 2039 // Enter safepoint region 2040 // Beware of deadlocks such as 6317397. 2041 // The per-thread Parker:: mutex is a classic leaf-lock. 2042 // In particular a thread must never block on the Threads_lock while 2043 // holding the Parker:: mutex. If safepoints are pending both the 2044 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 2045 ThreadBlockInVM tbivm(jt); 2046 2047 // Don't wait if cannot get lock since interference arises from 2048 // unparking. Also re-check interrupt before trying wait. 2049 if (Thread::is_interrupted(thread, false) || 2050 pthread_mutex_trylock(_mutex) != 0) { 2051 return; 2052 } 2053 2054 int status; 2055 if (_counter > 0) { // no wait needed 2056 _counter = 0; 2057 status = pthread_mutex_unlock(_mutex); 2058 assert_status(status == 0, status, "invariant"); 2059 // Paranoia to ensure our locked and lock-free paths interact 2060 // correctly with each other and Java-level accesses. 2061 OrderAccess::fence(); 2062 return; 2063 } 2064 2065 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 2066 jt->set_suspend_equivalent(); 2067 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2068 2069 assert(_cur_index == -1, "invariant"); 2070 if (time == 0) { 2071 _cur_index = REL_INDEX; // arbitrary choice when not timed 2072 status = pthread_cond_wait(&_cond[_cur_index], _mutex); 2073 assert_status(status == 0, status, "cond_timedwait"); 2074 } 2075 else { 2076 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 2077 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); 2078 assert_status(status == 0 || status == ETIMEDOUT, 2079 status, "cond_timedwait"); 2080 } 2081 _cur_index = -1; 2082 2083 _counter = 0; 2084 status = pthread_mutex_unlock(_mutex); 2085 assert_status(status == 0, status, "invariant"); 2086 // Paranoia to ensure our locked and lock-free paths interact 2087 // correctly with each other and Java-level accesses. 2088 OrderAccess::fence(); 2089 2090 // If externally suspended while waiting, re-suspend 2091 if (jt->handle_special_suspend_equivalent_condition()) { 2092 jt->java_suspend_self(); 2093 } 2094 } 2095 2096 void Parker::unpark() { 2097 int status = pthread_mutex_lock(_mutex); 2098 assert_status(status == 0, status, "invariant"); 2099 const int s = _counter; 2100 _counter = 1; 2101 // must capture correct index before unlocking 2102 int index = _cur_index; 2103 status = pthread_mutex_unlock(_mutex); 2104 assert_status(status == 0, status, "invariant"); 2105 2106 // Note that we signal() *after* dropping the lock for "immortal" Events. 2107 // This is safe and avoids a common class of futile wakeups. In rare 2108 // circumstances this can cause a thread to return prematurely from 2109 // cond_{timed}wait() but the spurious wakeup is benign and the victim 2110 // will simply re-test the condition and re-park itself. 2111 // This provides particular benefit if the underlying platform does not 2112 // provide wait morphing. 2113 2114 if (s < 1 && index != -1) { 2115 // thread is definitely parked 2116 status = pthread_cond_signal(&_cond[index]); 2117 assert_status(status == 0, status, "invariant"); 2118 } 2119 } 2120 2121 2122 #endif // !SOLARIS