1// Copyright 2012 the V8 project authors. All rights reserved. 2// Redistribution and use in source and binary forms, with or without 3// modification, are permitted provided that the following conditions are 4// met: 5// 6// * Redistributions of source code must retain the above copyright 7// notice, this list of conditions and the following disclaimer. 8// * Redistributions in binary form must reproduce the above 9// copyright notice, this list of conditions and the following 10// disclaimer in the documentation and/or other materials provided 11// with the distribution. 12// * Neither the name of Google Inc. nor the names of its 13// contributors may be used to endorse or promote products derived 14// from this software without specific prior written permission. 15// 16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28// Platform specific code for Linux goes here. For the POSIX comaptible parts 29// the implementation is in platform-posix.cc. 30 31#include <pthread.h> 32#include <semaphore.h> 33#include <signal.h> 34#include <sys/prctl.h> 35#include <sys/time.h> 36#include <sys/resource.h> 37#include <sys/syscall.h> 38#include <sys/types.h> 39#include <stdlib.h> 40 41#if defined(__GLIBC__) && !defined(__UCLIBC__) 42#include <execinfo.h> 43#include <cxxabi.h> 44#endif 45 46// Ubuntu Dapper requires memory pages to be marked as 47// executable. Otherwise, OS raises an exception when executing code 48// in that page. 49#include <sys/types.h> // mmap & munmap 50#include <sys/mman.h> // mmap & munmap 51#include <sys/stat.h> // open 52#include <fcntl.h> // open 53#include <unistd.h> // sysconf 54#include <strings.h> // index 55#include <errno.h> 56#include <stdarg.h> 57 58// GLibc on ARM defines mcontext_t has a typedef for 'struct sigcontext'. 59// Old versions of the C library <signal.h> didn't define the type. 60#if defined(__ANDROID__) && !defined(__BIONIC_HAVE_UCONTEXT_T) && \ 61 defined(__arm__) && !defined(__BIONIC_HAVE_STRUCT_SIGCONTEXT) 62#include <asm/sigcontext.h> 63#endif 64 65#undef MAP_TYPE 66 67#include "v8.h" 68 69#include "platform-posix.h" 70#include "platform.h" 71#include "v8threads.h" 72#include "vm-state-inl.h" 73 74 75namespace v8 { 76namespace internal { 77 78 79static Mutex* limit_mutex = NULL; 80 81 82#ifdef __arm__ 83static bool CPUInfoContainsString(const char * search_string) { 84 const char* file_name = "/proc/cpuinfo"; 85 // This is written as a straight shot one pass parser 86 // and not using STL string and ifstream because, 87 // on Linux, it's reading from a (non-mmap-able) 88 // character special device. 89 FILE* f = NULL; 90 const char* what = search_string; 91 92 if (NULL == (f = fopen(file_name, "r"))) { 93 OS::PrintError("Failed to open /proc/cpuinfo\n"); 94 return false; 95 } 96 97 int k; 98 while (EOF != (k = fgetc(f))) { 99 if (k == *what) { 100 ++what; 101 while ((*what != '\0') && (*what == fgetc(f))) { 102 ++what; 103 } 104 if (*what == '\0') { 105 fclose(f); 106 return true; 107 } else { 108 what = search_string; 109 } 110 } 111 } 112 fclose(f); 113 114 // Did not find string in the proc file. 115 return false; 116} 117 118 119bool OS::ArmCpuHasFeature(CpuFeature feature) { 120 const char* search_string = NULL; 121 // Simple detection of VFP at runtime for Linux. 122 // It is based on /proc/cpuinfo, which reveals hardware configuration 123 // to user-space applications. According to ARM (mid 2009), no similar 124 // facility is universally available on the ARM architectures, 125 // so it's up to individual OSes to provide such. 126 switch (feature) { 127 case VFP3: 128 search_string = "vfpv3"; 129 break; 130 case NEON: 131 search_string = "neon"; 132 break; 133 case ARMv7: 134 search_string = "ARMv7"; 135 break; 136 case SUDIV: 137 search_string = "idiva"; 138 break; 139 case VFP32DREGS: 140 // This case is handled specially below. 141 break; 142 default: 143 UNREACHABLE(); 144 } 145 146 if (feature == VFP32DREGS) { 147 return ArmCpuHasFeature(VFP3) && !CPUInfoContainsString("d16"); 148 } 149 150 if (CPUInfoContainsString(search_string)) { 151 return true; 152 } 153 154 if (feature == VFP3) { 155 // Some old kernels will report vfp not vfpv3. Here we make a last attempt 156 // to detect vfpv3 by checking for vfp *and* neon, since neon is only 157 // available on architectures with vfpv3. 158 // Checking neon on its own is not enough as it is possible to have neon 159 // without vfp. 160 if (CPUInfoContainsString("vfp") && CPUInfoContainsString("neon")) { 161 return true; 162 } 163 } 164 165 return false; 166} 167 168 169CpuImplementer OS::GetCpuImplementer() { 170 static bool use_cached_value = false; 171 static CpuImplementer cached_value = UNKNOWN_IMPLEMENTER; 172 if (use_cached_value) { 173 return cached_value; 174 } 175 if (CPUInfoContainsString("CPU implementer\t: 0x41")) { 176 cached_value = ARM_IMPLEMENTER; 177 } else if (CPUInfoContainsString("CPU implementer\t: 0x51")) { 178 cached_value = QUALCOMM_IMPLEMENTER; 179 } else { 180 cached_value = UNKNOWN_IMPLEMENTER; 181 } 182 use_cached_value = true; 183 return cached_value; 184} 185 186 187CpuPart OS::GetCpuPart(CpuImplementer implementer) { 188 static bool use_cached_value = false; 189 static CpuPart cached_value = CPU_UNKNOWN; 190 if (use_cached_value) { 191 return cached_value; 192 } 193 if (implementer == ARM_IMPLEMENTER) { 194 if (CPUInfoContainsString("CPU part\t: 0xc0f")) { 195 cached_value = CORTEX_A15; 196 } else if (CPUInfoContainsString("CPU part\t: 0xc0c")) { 197 cached_value = CORTEX_A12; 198 } else if (CPUInfoContainsString("CPU part\t: 0xc09")) { 199 cached_value = CORTEX_A9; 200 } else if (CPUInfoContainsString("CPU part\t: 0xc08")) { 201 cached_value = CORTEX_A8; 202 } else if (CPUInfoContainsString("CPU part\t: 0xc07")) { 203 cached_value = CORTEX_A7; 204 } else if (CPUInfoContainsString("CPU part\t: 0xc05")) { 205 cached_value = CORTEX_A5; 206 } else { 207 cached_value = CPU_UNKNOWN; 208 } 209 } else { 210 cached_value = CPU_UNKNOWN; 211 } 212 use_cached_value = true; 213 return cached_value; 214} 215 216 217bool OS::ArmUsingHardFloat() { 218 // GCC versions 4.6 and above define __ARM_PCS or __ARM_PCS_VFP to specify 219 // the Floating Point ABI used (PCS stands for Procedure Call Standard). 220 // We use these as well as a couple of other defines to statically determine 221 // what FP ABI used. 222 // GCC versions 4.4 and below don't support hard-fp. 223 // GCC versions 4.5 may support hard-fp without defining __ARM_PCS or 224 // __ARM_PCS_VFP. 225 226#define GCC_VERSION (__GNUC__ * 10000 \ 227 + __GNUC_MINOR__ * 100 \ 228 + __GNUC_PATCHLEVEL__) 229#if GCC_VERSION >= 40600 230#if defined(__ARM_PCS_VFP) 231 return true; 232#else 233 return false; 234#endif 235 236#elif GCC_VERSION < 40500 237 return false; 238 239#else 240#if defined(__ARM_PCS_VFP) 241 return true; 242#elif defined(__ARM_PCS) || defined(__SOFTFP__) || defined(__SOFTFP) || \ 243 !defined(__VFP_FP__) 244 return false; 245#else 246#error "Your version of GCC does not report the FP ABI compiled for." \ 247 "Please report it on this issue" \ 248 "http://code.google.com/p/v8/issues/detail?id=2140" 249 250#endif 251#endif 252#undef GCC_VERSION 253} 254 255#endif // def __arm__ 256 257 258#ifdef __mips__ 259bool OS::MipsCpuHasFeature(CpuFeature feature) { 260 const char* search_string = NULL; 261 const char* file_name = "/proc/cpuinfo"; 262 // Simple detection of FPU at runtime for Linux. 263 // It is based on /proc/cpuinfo, which reveals hardware configuration 264 // to user-space applications. According to MIPS (early 2010), no similar 265 // facility is universally available on the MIPS architectures, 266 // so it's up to individual OSes to provide such. 267 // 268 // This is written as a straight shot one pass parser 269 // and not using STL string and ifstream because, 270 // on Linux, it's reading from a (non-mmap-able) 271 // character special device. 272 273 switch (feature) { 274 case FPU: 275 search_string = "FPU"; 276 break; 277 default: 278 UNREACHABLE(); 279 } 280 281 FILE* f = NULL; 282 const char* what = search_string; 283 284 if (NULL == (f = fopen(file_name, "r"))) { 285 OS::PrintError("Failed to open /proc/cpuinfo\n"); 286 return false; 287 } 288 289 int k; 290 while (EOF != (k = fgetc(f))) { 291 if (k == *what) { 292 ++what; 293 while ((*what != '\0') && (*what == fgetc(f))) { 294 ++what; 295 } 296 if (*what == '\0') { 297 fclose(f); 298 return true; 299 } else { 300 what = search_string; 301 } 302 } 303 } 304 fclose(f); 305 306 // Did not find string in the proc file. 307 return false; 308} 309#endif // def __mips__ 310 311 312const char* OS::LocalTimezone(double time) { 313 if (std::isnan(time)) return ""; 314 time_t tv = static_cast<time_t>(floor(time/msPerSecond)); 315 struct tm* t = localtime(&tv); 316 if (NULL == t) return ""; 317 return t->tm_zone; 318} 319 320 321double OS::LocalTimeOffset() { 322 time_t tv = time(NULL); 323 struct tm* t = localtime(&tv); 324 // tm_gmtoff includes any daylight savings offset, so subtract it. 325 return static_cast<double>(t->tm_gmtoff * msPerSecond - 326 (t->tm_isdst > 0 ? 3600 * msPerSecond : 0)); 327} 328 329 330// We keep the lowest and highest addresses mapped as a quick way of 331// determining that pointers are outside the heap (used mostly in assertions 332// and verification). The estimate is conservative, i.e., not all addresses in 333// 'allocated' space are actually allocated to our heap. The range is 334// [lowest, highest), inclusive on the low and and exclusive on the high end. 335static void* lowest_ever_allocated = reinterpret_cast<void*>(-1); 336static void* highest_ever_allocated = reinterpret_cast<void*>(0); 337 338 339static void UpdateAllocatedSpaceLimits(void* address, int size) { 340 ASSERT(limit_mutex != NULL); 341 ScopedLock lock(limit_mutex); 342 343 lowest_ever_allocated = Min(lowest_ever_allocated, address); 344 highest_ever_allocated = 345 Max(highest_ever_allocated, 346 reinterpret_cast<void*>(reinterpret_cast<char*>(address) + size)); 347} 348 349 350bool OS::IsOutsideAllocatedSpace(void* address) { 351 return address < lowest_ever_allocated || address >= highest_ever_allocated; 352} 353 354 355void* OS::Allocate(const size_t requested, 356 size_t* allocated, 357 bool is_executable) { 358 const size_t msize = RoundUp(requested, AllocateAlignment()); 359 int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0); 360 void* addr = OS::GetRandomMmapAddr(); 361 void* mbase = mmap(addr, msize, prot, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); 362 if (mbase == MAP_FAILED) { 363 LOG(i::Isolate::Current(), 364 StringEvent("OS::Allocate", "mmap failed")); 365 return NULL; 366 } 367 *allocated = msize; 368 UpdateAllocatedSpaceLimits(mbase, msize); 369 return mbase; 370} 371 372 373void OS::DumpBacktrace() { 374 // backtrace is a glibc extension. 375#if defined(__GLIBC__) && !defined(__UCLIBC__) 376 POSIXBacktraceHelper<backtrace, backtrace_symbols>::DumpBacktrace(); 377#endif 378} 379 380 381class PosixMemoryMappedFile : public OS::MemoryMappedFile { 382 public: 383 PosixMemoryMappedFile(FILE* file, void* memory, int size) 384 : file_(file), memory_(memory), size_(size) { } 385 virtual ~PosixMemoryMappedFile(); 386 virtual void* memory() { return memory_; } 387 virtual int size() { return size_; } 388 private: 389 FILE* file_; 390 void* memory_; 391 int size_; 392}; 393 394 395OS::MemoryMappedFile* OS::MemoryMappedFile::open(const char* name) { 396 FILE* file = fopen(name, "r+"); 397 if (file == NULL) return NULL; 398 399 fseek(file, 0, SEEK_END); 400 int size = ftell(file); 401 402 void* memory = 403 mmap(OS::GetRandomMmapAddr(), 404 size, 405 PROT_READ | PROT_WRITE, 406 MAP_SHARED, 407 fileno(file), 408 0); 409 return new PosixMemoryMappedFile(file, memory, size); 410} 411 412 413OS::MemoryMappedFile* OS::MemoryMappedFile::create(const char* name, int size, 414 void* initial) { 415 FILE* file = fopen(name, "w+"); 416 if (file == NULL) return NULL; 417 int result = fwrite(initial, size, 1, file); 418 if (result < 1) { 419 fclose(file); 420 return NULL; 421 } 422 void* memory = 423 mmap(OS::GetRandomMmapAddr(), 424 size, 425 PROT_READ | PROT_WRITE, 426 MAP_SHARED, 427 fileno(file), 428 0); 429 return new PosixMemoryMappedFile(file, memory, size); 430} 431 432 433PosixMemoryMappedFile::~PosixMemoryMappedFile() { 434 if (memory_) OS::Free(memory_, size_); 435 fclose(file_); 436} 437 438 439void OS::LogSharedLibraryAddresses() { 440 // This function assumes that the layout of the file is as follows: 441 // hex_start_addr-hex_end_addr rwxp <unused data> [binary_file_name] 442 // If we encounter an unexpected situation we abort scanning further entries. 443 FILE* fp = fopen("/proc/self/maps", "r"); 444 if (fp == NULL) return; 445 446 // Allocate enough room to be able to store a full file name. 447 const int kLibNameLen = FILENAME_MAX + 1; 448 char* lib_name = reinterpret_cast<char*>(malloc(kLibNameLen)); 449 450 i::Isolate* isolate = ISOLATE; 451 // This loop will terminate once the scanning hits an EOF. 452 while (true) { 453 uintptr_t start, end; 454 char attr_r, attr_w, attr_x, attr_p; 455 // Parse the addresses and permission bits at the beginning of the line. 456 if (fscanf(fp, "%" V8PRIxPTR "-%" V8PRIxPTR, &start, &end) != 2) break; 457 if (fscanf(fp, " %c%c%c%c", &attr_r, &attr_w, &attr_x, &attr_p) != 4) break; 458 459 int c; 460 if (attr_r == 'r' && attr_w != 'w' && attr_x == 'x') { 461 // Found a read-only executable entry. Skip characters until we reach 462 // the beginning of the filename or the end of the line. 463 do { 464 c = getc(fp); 465 } while ((c != EOF) && (c != '\n') && (c != '/') && (c != '[')); 466 if (c == EOF) break; // EOF: Was unexpected, just exit. 467 468 // Process the filename if found. 469 if ((c == '/') || (c == '[')) { 470 // Push the '/' or '[' back into the stream to be read below. 471 ungetc(c, fp); 472 473 // Read to the end of the line. Exit if the read fails. 474 if (fgets(lib_name, kLibNameLen, fp) == NULL) break; 475 476 // Drop the newline character read by fgets. We do not need to check 477 // for a zero-length string because we know that we at least read the 478 // '/' or '[' character. 479 lib_name[strlen(lib_name) - 1] = '\0'; 480 } else { 481 // No library name found, just record the raw address range. 482 snprintf(lib_name, kLibNameLen, 483 "%08" V8PRIxPTR "-%08" V8PRIxPTR, start, end); 484 } 485 LOG(isolate, SharedLibraryEvent(lib_name, start, end)); 486 } else { 487 // Entry not describing executable data. Skip to end of line to set up 488 // reading the next entry. 489 do { 490 c = getc(fp); 491 } while ((c != EOF) && (c != '\n')); 492 if (c == EOF) break; 493 } 494 } 495 free(lib_name); 496 fclose(fp); 497} 498 499 500void OS::SignalCodeMovingGC() { 501 // Support for ll_prof.py. 502 // 503 // The Linux profiler built into the kernel logs all mmap's with 504 // PROT_EXEC so that analysis tools can properly attribute ticks. We 505 // do a mmap with a name known by ll_prof.py and immediately munmap 506 // it. This injects a GC marker into the stream of events generated 507 // by the kernel and allows us to synchronize V8 code log and the 508 // kernel log. 509 int size = sysconf(_SC_PAGESIZE); 510 FILE* f = fopen(FLAG_gc_fake_mmap, "w+"); 511 if (f == NULL) { 512 OS::PrintError("Failed to open %s\n", FLAG_gc_fake_mmap); 513 OS::Abort(); 514 } 515 void* addr = mmap(OS::GetRandomMmapAddr(), 516 size, 517#if defined(__native_client__) 518 // The Native Client port of V8 uses an interpreter, 519 // so code pages don't need PROT_EXEC. 520 PROT_READ, 521#else 522 PROT_READ | PROT_EXEC, 523#endif 524 MAP_PRIVATE, 525 fileno(f), 526 0); 527 ASSERT(addr != MAP_FAILED); 528 OS::Free(addr, size); 529 fclose(f); 530} 531 532 533int OS::StackWalk(Vector<OS::StackFrame> frames) { 534 // backtrace is a glibc extension. 535#if defined(__GLIBC__) && !defined(__UCLIBC__) 536 return POSIXBacktraceHelper<backtrace, backtrace_symbols>::StackWalk(frames); 537#else 538 return 0; 539#endif 540} 541 542 543// Constants used for mmap. 544static const int kMmapFd = -1; 545static const int kMmapFdOffset = 0; 546 547 548VirtualMemory::VirtualMemory() : address_(NULL), size_(0) { } 549 550 551VirtualMemory::VirtualMemory(size_t size) 552 : address_(ReserveRegion(size)), size_(size) { } 553 554 555VirtualMemory::VirtualMemory(size_t size, size_t alignment) 556 : address_(NULL), size_(0) { 557 ASSERT(IsAligned(alignment, static_cast<intptr_t>(OS::AllocateAlignment()))); 558 size_t request_size = RoundUp(size + alignment, 559 static_cast<intptr_t>(OS::AllocateAlignment())); 560 void* reservation = mmap(OS::GetRandomMmapAddr(), 561 request_size, 562 PROT_NONE, 563 MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, 564 kMmapFd, 565 kMmapFdOffset); 566 if (reservation == MAP_FAILED) return; 567 568 Address base = static_cast<Address>(reservation); 569 Address aligned_base = RoundUp(base, alignment); 570 ASSERT_LE(base, aligned_base); 571 572 // Unmap extra memory reserved before and after the desired block. 573 if (aligned_base != base) { 574 size_t prefix_size = static_cast<size_t>(aligned_base - base); 575 OS::Free(base, prefix_size); 576 request_size -= prefix_size; 577 } 578 579 size_t aligned_size = RoundUp(size, OS::AllocateAlignment()); 580 ASSERT_LE(aligned_size, request_size); 581 582 if (aligned_size != request_size) { 583 size_t suffix_size = request_size - aligned_size; 584 OS::Free(aligned_base + aligned_size, suffix_size); 585 request_size -= suffix_size; 586 } 587 588 ASSERT(aligned_size == request_size); 589 590 address_ = static_cast<void*>(aligned_base); 591 size_ = aligned_size; 592} 593 594 595VirtualMemory::~VirtualMemory() { 596 if (IsReserved()) { 597 bool result = ReleaseRegion(address(), size()); 598 ASSERT(result); 599 USE(result); 600 } 601} 602 603 604bool VirtualMemory::IsReserved() { 605 return address_ != NULL; 606} 607 608 609void VirtualMemory::Reset() { 610 address_ = NULL; 611 size_ = 0; 612} 613 614 615bool VirtualMemory::Commit(void* address, size_t size, bool is_executable) { 616 return CommitRegion(address, size, is_executable); 617} 618 619 620bool VirtualMemory::Uncommit(void* address, size_t size) { 621 return UncommitRegion(address, size); 622} 623 624 625bool VirtualMemory::Guard(void* address) { 626 OS::Guard(address, OS::CommitPageSize()); 627 return true; 628} 629 630 631void* VirtualMemory::ReserveRegion(size_t size) { 632 void* result = mmap(OS::GetRandomMmapAddr(), 633 size, 634 PROT_NONE, 635 MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, 636 kMmapFd, 637 kMmapFdOffset); 638 639 if (result == MAP_FAILED) return NULL; 640 641 return result; 642} 643 644 645bool VirtualMemory::CommitRegion(void* base, size_t size, bool is_executable) { 646#if defined(__native_client__) 647 // The Native Client port of V8 uses an interpreter, 648 // so code pages don't need PROT_EXEC. 649 int prot = PROT_READ | PROT_WRITE; 650#else 651 int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0); 652#endif 653 if (MAP_FAILED == mmap(base, 654 size, 655 prot, 656 MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, 657 kMmapFd, 658 kMmapFdOffset)) { 659 return false; 660 } 661 662 UpdateAllocatedSpaceLimits(base, size); 663 return true; 664} 665 666 667bool VirtualMemory::UncommitRegion(void* base, size_t size) { 668 return mmap(base, 669 size, 670 PROT_NONE, 671 MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE | MAP_FIXED, 672 kMmapFd, 673 kMmapFdOffset) != MAP_FAILED; 674} 675 676 677bool VirtualMemory::ReleaseRegion(void* base, size_t size) { 678 return munmap(base, size) == 0; 679} 680 681 682bool VirtualMemory::HasLazyCommits() { 683 return true; 684} 685 686 687class LinuxSemaphore : public Semaphore { 688 public: 689 explicit LinuxSemaphore(int count) { sem_init(&sem_, 0, count); } 690 virtual ~LinuxSemaphore() { sem_destroy(&sem_); } 691 692 virtual void Wait(); 693 virtual bool Wait(int timeout); 694 virtual void Signal() { sem_post(&sem_); } 695 private: 696 sem_t sem_; 697}; 698 699 700void LinuxSemaphore::Wait() { 701 while (true) { 702 int result = sem_wait(&sem_); 703 if (result == 0) return; // Successfully got semaphore. 704 CHECK(result == -1 && errno == EINTR); // Signal caused spurious wakeup. 705 } 706} 707 708 709#ifndef TIMEVAL_TO_TIMESPEC 710#define TIMEVAL_TO_TIMESPEC(tv, ts) do { \ 711 (ts)->tv_sec = (tv)->tv_sec; \ 712 (ts)->tv_nsec = (tv)->tv_usec * 1000; \ 713} while (false) 714#endif 715 716 717bool LinuxSemaphore::Wait(int timeout) { 718 const long kOneSecondMicros = 1000000; // NOLINT 719 720 // Split timeout into second and nanosecond parts. 721 struct timeval delta; 722 delta.tv_usec = timeout % kOneSecondMicros; 723 delta.tv_sec = timeout / kOneSecondMicros; 724 725 struct timeval current_time; 726 // Get the current time. 727 if (gettimeofday(¤t_time, NULL) == -1) { 728 return false; 729 } 730 731 // Calculate time for end of timeout. 732 struct timeval end_time; 733 timeradd(¤t_time, &delta, &end_time); 734 735 struct timespec ts; 736 TIMEVAL_TO_TIMESPEC(&end_time, &ts); 737 // Wait for semaphore signalled or timeout. 738 while (true) { 739 int result = sem_timedwait(&sem_, &ts); 740 if (result == 0) return true; // Successfully got semaphore. 741 if (result > 0) { 742 // For glibc prior to 2.3.4 sem_timedwait returns the error instead of -1. 743 errno = result; 744 result = -1; 745 } 746 if (result == -1 && errno == ETIMEDOUT) return false; // Timeout. 747 CHECK(result == -1 && errno == EINTR); // Signal caused spurious wakeup. 748 } 749} 750 751 752Semaphore* OS::CreateSemaphore(int count) { 753 return new LinuxSemaphore(count); 754} 755 756 757void OS::SetUp() { 758 // Seed the random number generator. We preserve microsecond resolution. 759 uint64_t seed = Ticks() ^ (getpid() << 16); 760 srandom(static_cast<unsigned int>(seed)); 761 limit_mutex = CreateMutex(); 762} 763 764 765void OS::TearDown() { 766 delete limit_mutex; 767} 768 769 770} } // namespace v8::internal 771