1//===- Signals.cpp - Generic Unix Signals Implementation -----*- C++ -*-===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8// 9// This file defines some helpful functions for dealing with the possibility of 10// Unix signals occurring while your program is running. 11// 12//===----------------------------------------------------------------------===// 13// 14// This file is extremely careful to only do signal-safe things while in a 15// signal handler. In particular, memory allocation and acquiring a mutex 16// while in a signal handler should never occur. ManagedStatic isn't usable from 17// a signal handler for 2 reasons: 18// 19// 1. Creating a new one allocates. 20// 2. The signal handler could fire while llvm_shutdown is being processed, in 21// which case the ManagedStatic is in an unknown state because it could 22// already have been destroyed, or be in the process of being destroyed. 23// 24// Modifying the behavior of the signal handlers (such as registering new ones) 25// can acquire a mutex, but all this guarantees is that the signal handler 26// behavior is only modified by one thread at a time. A signal handler can still 27// fire while this occurs! 28// 29// Adding work to a signal handler requires lock-freedom (and assume atomics are 30// always lock-free) because the signal handler could fire while new work is 31// being added. 32// 33//===----------------------------------------------------------------------===// 34 35#include "Unix.h" 36#include "llvm/ADT/STLExtras.h" 37#include "llvm/Config/config.h" 38#include "llvm/Demangle/Demangle.h" 39#include "llvm/Support/ExitCodes.h" 40#include "llvm/Support/FileSystem.h" 41#include "llvm/Support/FileUtilities.h" 42#include "llvm/Support/Format.h" 43#include "llvm/Support/MemoryBuffer.h" 44#include "llvm/Support/Mutex.h" 45#include "llvm/Support/Program.h" 46#include "llvm/Support/SaveAndRestore.h" 47#include "llvm/Support/raw_ostream.h" 48#include <algorithm> 49#include <string> 50#ifdef HAVE_BACKTRACE 51#include BACKTRACE_HEADER // For backtrace(). 52#endif 53#if HAVE_SIGNAL_H 54#include <signal.h> 55#endif 56#if HAVE_SYS_STAT_H 57#include <sys/stat.h> 58#endif 59#if HAVE_DLFCN_H 60#include <dlfcn.h> 61#endif 62#if HAVE_MACH_MACH_H 63#include <mach/mach.h> 64#endif 65#ifdef __APPLE__ 66#include <mach-o/dyld.h> 67#endif 68#if HAVE_LINK_H 69#include <link.h> 70#endif 71#ifdef HAVE__UNWIND_BACKTRACE 72// FIXME: We should be able to use <unwind.h> for any target that has an 73// _Unwind_Backtrace function, but on FreeBSD the configure test passes 74// despite the function not existing, and on Android, <unwind.h> conflicts 75// with <link.h>. 76#ifdef __GLIBC__ 77#include <unwind.h> 78#else 79#undef HAVE__UNWIND_BACKTRACE 80#endif 81#endif 82 83using namespace llvm; 84 85static void SignalHandler(int Sig); // defined below. 86static void InfoSignalHandler(int Sig); // defined below. 87 88using SignalHandlerFunctionType = void (*)(); 89/// The function to call if ctrl-c is pressed. 90static std::atomic<SignalHandlerFunctionType> InterruptFunction = nullptr; 91static std::atomic<SignalHandlerFunctionType> InfoSignalFunction = nullptr; 92/// The function to call on SIGPIPE (one-time use only). 93static std::atomic<SignalHandlerFunctionType> OneShotPipeSignalFunction = 94 nullptr; 95 96namespace { 97/// Signal-safe removal of files. 98/// Inserting and erasing from the list isn't signal-safe, but removal of files 99/// themselves is signal-safe. Memory is freed when the head is freed, deletion 100/// is therefore not signal-safe either. 101class FileToRemoveList { 102 std::atomic<char *> Filename = nullptr; 103 std::atomic<FileToRemoveList *> Next = nullptr; 104 105 FileToRemoveList() = default; 106 // Not signal-safe. 107 FileToRemoveList(const std::string &str) : Filename(strdup(str.c_str())) {} 108 109public: 110 // Not signal-safe. 111 ~FileToRemoveList() { 112 if (FileToRemoveList *N = Next.exchange(nullptr)) 113 delete N; 114 if (char *F = Filename.exchange(nullptr)) 115 free(F); 116 } 117 118 // Not signal-safe. 119 static void insert(std::atomic<FileToRemoveList *> &Head, 120 const std::string &Filename) { 121 // Insert the new file at the end of the list. 122 FileToRemoveList *NewHead = new FileToRemoveList(Filename); 123 std::atomic<FileToRemoveList *> *InsertionPoint = &Head; 124 FileToRemoveList *OldHead = nullptr; 125 while (!InsertionPoint->compare_exchange_strong(OldHead, NewHead)) { 126 InsertionPoint = &OldHead->Next; 127 OldHead = nullptr; 128 } 129 } 130 131 // Not signal-safe. 132 static void erase(std::atomic<FileToRemoveList *> &Head, 133 const std::string &Filename) { 134 // Use a lock to avoid concurrent erase: the comparison would access 135 // free'd memory. 136 static ManagedStatic<sys::SmartMutex<true>> Lock; 137 sys::SmartScopedLock<true> Writer(*Lock); 138 139 for (FileToRemoveList *Current = Head.load(); Current; 140 Current = Current->Next.load()) { 141 if (char *OldFilename = Current->Filename.load()) { 142 if (OldFilename != Filename) 143 continue; 144 // Leave an empty filename. 145 OldFilename = Current->Filename.exchange(nullptr); 146 // The filename might have become null between the time we 147 // compared it and we exchanged it. 148 if (OldFilename) 149 free(OldFilename); 150 } 151 } 152 } 153 154 // Signal-safe. 155 static void removeAllFiles(std::atomic<FileToRemoveList *> &Head) { 156 // If cleanup were to occur while we're removing files we'd have a bad time. 157 // Make sure we're OK by preventing cleanup from doing anything while we're 158 // removing files. If cleanup races with us and we win we'll have a leak, 159 // but we won't crash. 160 FileToRemoveList *OldHead = Head.exchange(nullptr); 161 162 for (FileToRemoveList *currentFile = OldHead; currentFile; 163 currentFile = currentFile->Next.load()) { 164 // If erasing was occuring while we're trying to remove files we'd look 165 // at free'd data. Take away the path and put it back when done. 166 if (char *path = currentFile->Filename.exchange(nullptr)) { 167 // Get the status so we can determine if it's a file or directory. If we 168 // can't stat the file, ignore it. 169 struct stat buf; 170 if (stat(path, &buf) != 0) 171 continue; 172 173 // If this is not a regular file, ignore it. We want to prevent removal 174 // of special files like /dev/null, even if the compiler is being run 175 // with the super-user permissions. 176 if (!S_ISREG(buf.st_mode)) 177 continue; 178 179 // Otherwise, remove the file. We ignore any errors here as there is 180 // nothing else we can do. 181 unlink(path); 182 183 // We're done removing the file, erasing can safely proceed. 184 currentFile->Filename.exchange(path); 185 } 186 } 187 188 // We're done removing files, cleanup can safely proceed. 189 Head.exchange(OldHead); 190 } 191}; 192static std::atomic<FileToRemoveList *> FilesToRemove = nullptr; 193 194/// Clean up the list in a signal-friendly manner. 195/// Recall that signals can fire during llvm_shutdown. If this occurs we should 196/// either clean something up or nothing at all, but we shouldn't crash! 197struct FilesToRemoveCleanup { 198 // Not signal-safe. 199 ~FilesToRemoveCleanup() { 200 FileToRemoveList *Head = FilesToRemove.exchange(nullptr); 201 if (Head) 202 delete Head; 203 } 204}; 205} // namespace 206 207static StringRef Argv0; 208 209/// Signals that represent requested termination. There's no bug or failure, or 210/// if there is, it's not our direct responsibility. For whatever reason, our 211/// continued execution is no longer desirable. 212static const int IntSigs[] = {SIGHUP, SIGINT, SIGTERM, SIGUSR2}; 213 214/// Signals that represent that we have a bug, and our prompt termination has 215/// been ordered. 216static const int KillSigs[] = {SIGILL, 217 SIGTRAP, 218 SIGABRT, 219 SIGFPE, 220 SIGBUS, 221 SIGSEGV, 222 SIGQUIT 223#ifdef SIGSYS 224 , 225 SIGSYS 226#endif 227#ifdef SIGXCPU 228 , 229 SIGXCPU 230#endif 231#ifdef SIGXFSZ 232 , 233 SIGXFSZ 234#endif 235#ifdef SIGEMT 236 , 237 SIGEMT 238#endif 239}; 240 241/// Signals that represent requests for status. 242static const int InfoSigs[] = {SIGUSR1 243#ifdef SIGINFO 244 , 245 SIGINFO 246#endif 247}; 248 249static const size_t NumSigs = std::size(IntSigs) + std::size(KillSigs) + 250 std::size(InfoSigs) + 1 /* SIGPIPE */; 251 252static std::atomic<unsigned> NumRegisteredSignals = 0; 253static struct { 254 struct sigaction SA; 255 int SigNo; 256} RegisteredSignalInfo[NumSigs]; 257 258#if defined(HAVE_SIGALTSTACK) 259// Hold onto both the old and new alternate signal stack so that it's not 260// reported as a leak. We don't make any attempt to remove our alt signal 261// stack if we remove our signal handlers; that can't be done reliably if 262// someone else is also trying to do the same thing. 263static stack_t OldAltStack; 264LLVM_ATTRIBUTE_USED static void *NewAltStackPointer; 265 266static void CreateSigAltStack() { 267 const size_t AltStackSize = MINSIGSTKSZ + 64 * 1024; 268 269 // If we're executing on the alternate stack, or we already have an alternate 270 // signal stack that we're happy with, there's nothing for us to do. Don't 271 // reduce the size, some other part of the process might need a larger stack 272 // than we do. 273 if (sigaltstack(nullptr, &OldAltStack) != 0 || 274 OldAltStack.ss_flags & SS_ONSTACK || 275 (OldAltStack.ss_sp && OldAltStack.ss_size >= AltStackSize)) 276 return; 277 278 stack_t AltStack = {}; 279 AltStack.ss_sp = static_cast<char *>(safe_malloc(AltStackSize)); 280 NewAltStackPointer = AltStack.ss_sp; // Save to avoid reporting a leak. 281 AltStack.ss_size = AltStackSize; 282 if (sigaltstack(&AltStack, &OldAltStack) != 0) 283 free(AltStack.ss_sp); 284} 285#else 286static void CreateSigAltStack() {} 287#endif 288 289static void RegisterHandlers() { // Not signal-safe. 290 // The mutex prevents other threads from registering handlers while we're 291 // doing it. We also have to protect the handlers and their count because 292 // a signal handler could fire while we're registeting handlers. 293 static ManagedStatic<sys::SmartMutex<true>> SignalHandlerRegistrationMutex; 294 sys::SmartScopedLock<true> Guard(*SignalHandlerRegistrationMutex); 295 296 // If the handlers are already registered, we're done. 297 if (NumRegisteredSignals.load() != 0) 298 return; 299 300 // Create an alternate stack for signal handling. This is necessary for us to 301 // be able to reliably handle signals due to stack overflow. 302 CreateSigAltStack(); 303 304 enum class SignalKind { IsKill, IsInfo }; 305 auto registerHandler = [&](int Signal, SignalKind Kind) { 306 unsigned Index = NumRegisteredSignals.load(); 307 assert(Index < std::size(RegisteredSignalInfo) && 308 "Out of space for signal handlers!"); 309 310 struct sigaction NewHandler; 311 312 switch (Kind) { 313 case SignalKind::IsKill: 314 NewHandler.sa_handler = SignalHandler; 315 NewHandler.sa_flags = SA_NODEFER | SA_RESETHAND | SA_ONSTACK; 316 break; 317 case SignalKind::IsInfo: 318 NewHandler.sa_handler = InfoSignalHandler; 319 NewHandler.sa_flags = SA_ONSTACK; 320 break; 321 } 322 sigemptyset(&NewHandler.sa_mask); 323 324 // Install the new handler, save the old one in RegisteredSignalInfo. 325 sigaction(Signal, &NewHandler, &RegisteredSignalInfo[Index].SA); 326 RegisteredSignalInfo[Index].SigNo = Signal; 327 ++NumRegisteredSignals; 328 }; 329 330 for (auto S : IntSigs) 331 registerHandler(S, SignalKind::IsKill); 332 for (auto S : KillSigs) 333 registerHandler(S, SignalKind::IsKill); 334 if (OneShotPipeSignalFunction) 335 registerHandler(SIGPIPE, SignalKind::IsKill); 336 for (auto S : InfoSigs) 337 registerHandler(S, SignalKind::IsInfo); 338} 339 340void sys::unregisterHandlers() { 341 // Restore all of the signal handlers to how they were before we showed up. 342 for (unsigned i = 0, e = NumRegisteredSignals.load(); i != e; ++i) { 343 sigaction(RegisteredSignalInfo[i].SigNo, &RegisteredSignalInfo[i].SA, 344 nullptr); 345 --NumRegisteredSignals; 346 } 347} 348 349/// Process the FilesToRemove list. 350static void RemoveFilesToRemove() { 351 FileToRemoveList::removeAllFiles(FilesToRemove); 352} 353 354void sys::CleanupOnSignal(uintptr_t Context) { 355 int Sig = (int)Context; 356 357 if (llvm::is_contained(InfoSigs, Sig)) { 358 InfoSignalHandler(Sig); 359 return; 360 } 361 362 RemoveFilesToRemove(); 363 364 if (llvm::is_contained(IntSigs, Sig) || Sig == SIGPIPE) 365 return; 366 367 llvm::sys::RunSignalHandlers(); 368} 369 370// The signal handler that runs. 371static void SignalHandler(int Sig) { 372 // Restore the signal behavior to default, so that the program actually 373 // crashes when we return and the signal reissues. This also ensures that if 374 // we crash in our signal handler that the program will terminate immediately 375 // instead of recursing in the signal handler. 376 sys::unregisterHandlers(); 377 378 // Unmask all potentially blocked kill signals. 379 sigset_t SigMask; 380 sigfillset(&SigMask); 381 sigprocmask(SIG_UNBLOCK, &SigMask, nullptr); 382 383 { 384 RemoveFilesToRemove(); 385 386 if (Sig == SIGPIPE) 387 if (auto OldOneShotPipeFunction = 388 OneShotPipeSignalFunction.exchange(nullptr)) 389 return OldOneShotPipeFunction(); 390 391 bool IsIntSig = llvm::is_contained(IntSigs, Sig); 392 if (IsIntSig) 393 if (auto OldInterruptFunction = InterruptFunction.exchange(nullptr)) 394 return OldInterruptFunction(); 395 396 if (Sig == SIGPIPE || IsIntSig) { 397 raise(Sig); // Execute the default handler. 398 return; 399 } 400 } 401 402 // Otherwise if it is a fault (like SEGV) run any handler. 403 llvm::sys::RunSignalHandlers(); 404 405#ifdef __s390__ 406 // On S/390, certain signals are delivered with PSW Address pointing to 407 // *after* the faulting instruction. Simply returning from the signal 408 // handler would continue execution after that point, instead of 409 // re-raising the signal. Raise the signal manually in those cases. 410 if (Sig == SIGILL || Sig == SIGFPE || Sig == SIGTRAP) 411 raise(Sig); 412#endif 413} 414 415static void InfoSignalHandler(int Sig) { 416 SaveAndRestore SaveErrnoDuringASignalHandler(errno); 417 if (SignalHandlerFunctionType CurrentInfoFunction = InfoSignalFunction) 418 CurrentInfoFunction(); 419} 420 421void llvm::sys::RunInterruptHandlers() { RemoveFilesToRemove(); } 422 423void llvm::sys::SetInterruptFunction(void (*IF)()) { 424 InterruptFunction.exchange(IF); 425 RegisterHandlers(); 426} 427 428void llvm::sys::SetInfoSignalFunction(void (*Handler)()) { 429 InfoSignalFunction.exchange(Handler); 430 RegisterHandlers(); 431} 432 433void llvm::sys::SetOneShotPipeSignalFunction(void (*Handler)()) { 434 OneShotPipeSignalFunction.exchange(Handler); 435 RegisterHandlers(); 436} 437 438void llvm::sys::DefaultOneShotPipeSignalHandler() { 439 // Send a special return code that drivers can check for, from sysexits.h. 440 exit(EX_IOERR); 441} 442 443// The public API 444bool llvm::sys::RemoveFileOnSignal(StringRef Filename, std::string *ErrMsg) { 445 // Ensure that cleanup will occur as soon as one file is added. 446 static ManagedStatic<FilesToRemoveCleanup> FilesToRemoveCleanup; 447 *FilesToRemoveCleanup; 448 FileToRemoveList::insert(FilesToRemove, Filename.str()); 449 RegisterHandlers(); 450 return false; 451} 452 453// The public API 454void llvm::sys::DontRemoveFileOnSignal(StringRef Filename) { 455 FileToRemoveList::erase(FilesToRemove, Filename.str()); 456} 457 458/// Add a function to be called when a signal is delivered to the process. The 459/// handler can have a cookie passed to it to identify what instance of the 460/// handler it is. 461void llvm::sys::AddSignalHandler(sys::SignalHandlerCallback FnPtr, 462 void *Cookie) { // Signal-safe. 463 insertSignalHandler(FnPtr, Cookie); 464 RegisterHandlers(); 465} 466 467#if ENABLE_BACKTRACES && defined(HAVE_BACKTRACE) && HAVE_LINK_H && \ 468 (defined(__linux__) || defined(__FreeBSD__) || \ 469 defined(__FreeBSD_kernel__) || defined(__NetBSD__)) 470struct DlIteratePhdrData { 471 void **StackTrace; 472 int depth; 473 bool first; 474 const char **modules; 475 intptr_t *offsets; 476 const char *main_exec_name; 477}; 478 479static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) { 480 DlIteratePhdrData *data = (DlIteratePhdrData *)arg; 481 const char *name = data->first ? data->main_exec_name : info->dlpi_name; 482 data->first = false; 483 for (int i = 0; i < info->dlpi_phnum; i++) { 484 const auto *phdr = &info->dlpi_phdr[i]; 485 if (phdr->p_type != PT_LOAD) 486 continue; 487 intptr_t beg = info->dlpi_addr + phdr->p_vaddr; 488 intptr_t end = beg + phdr->p_memsz; 489 for (int j = 0; j < data->depth; j++) { 490 if (data->modules[j]) 491 continue; 492 intptr_t addr = (intptr_t)data->StackTrace[j]; 493 if (beg <= addr && addr < end) { 494 data->modules[j] = name; 495 data->offsets[j] = addr - info->dlpi_addr; 496 } 497 } 498 } 499 return 0; 500} 501 502/// If this is an ELF platform, we can find all loaded modules and their virtual 503/// addresses with dl_iterate_phdr. 504static bool findModulesAndOffsets(void **StackTrace, int Depth, 505 const char **Modules, intptr_t *Offsets, 506 const char *MainExecutableName, 507 StringSaver &StrPool) { 508 DlIteratePhdrData data = {StackTrace, Depth, true, 509 Modules, Offsets, MainExecutableName}; 510 dl_iterate_phdr(dl_iterate_phdr_cb, &data); 511 return true; 512} 513#elif ENABLE_BACKTRACES && defined(__APPLE__) && defined(__LP64__) 514static bool findModulesAndOffsets(void **StackTrace, int Depth, 515 const char **Modules, intptr_t *Offsets, 516 const char *MainExecutableName, 517 StringSaver &StrPool) { 518 uint32_t NumImgs = _dyld_image_count(); 519 for (uint32_t ImageIndex = 0; ImageIndex < NumImgs; ImageIndex++) { 520 const char *Name = _dyld_get_image_name(ImageIndex); 521 intptr_t Slide = _dyld_get_image_vmaddr_slide(ImageIndex); 522 auto *Header = 523 (const struct mach_header_64 *)_dyld_get_image_header(ImageIndex); 524 if (Header == NULL) 525 continue; 526 auto Cmd = (const struct load_command *)(&Header[1]); 527 for (uint32_t CmdNum = 0; CmdNum < Header->ncmds; ++CmdNum) { 528 uint32_t BaseCmd = Cmd->cmd & ~LC_REQ_DYLD; 529 if (BaseCmd == LC_SEGMENT_64) { 530 auto CmdSeg64 = (const struct segment_command_64 *)Cmd; 531 for (int j = 0; j < Depth; j++) { 532 if (Modules[j]) 533 continue; 534 intptr_t Addr = (intptr_t)StackTrace[j]; 535 if ((intptr_t)CmdSeg64->vmaddr + Slide <= Addr && 536 Addr < intptr_t(CmdSeg64->vmaddr + CmdSeg64->vmsize + Slide)) { 537 Modules[j] = Name; 538 Offsets[j] = Addr - Slide; 539 } 540 } 541 } 542 Cmd = (const load_command *)(((const char *)Cmd) + (Cmd->cmdsize)); 543 } 544 } 545 return true; 546} 547#else 548/// Backtraces are not enabled or we don't yet know how to find all loaded DSOs 549/// on this platform. 550static bool findModulesAndOffsets(void **StackTrace, int Depth, 551 const char **Modules, intptr_t *Offsets, 552 const char *MainExecutableName, 553 StringSaver &StrPool) { 554 return false; 555} 556#endif // ENABLE_BACKTRACES && ... (findModulesAndOffsets variants) 557 558#if ENABLE_BACKTRACES && defined(HAVE__UNWIND_BACKTRACE) 559static int unwindBacktrace(void **StackTrace, int MaxEntries) { 560 if (MaxEntries < 0) 561 return 0; 562 563 // Skip the first frame ('unwindBacktrace' itself). 564 int Entries = -1; 565 566 auto HandleFrame = [&](_Unwind_Context *Context) -> _Unwind_Reason_Code { 567 // Apparently we need to detect reaching the end of the stack ourselves. 568 void *IP = (void *)_Unwind_GetIP(Context); 569 if (!IP) 570 return _URC_END_OF_STACK; 571 572 assert(Entries < MaxEntries && "recursively called after END_OF_STACK?"); 573 if (Entries >= 0) 574 StackTrace[Entries] = IP; 575 576 if (++Entries == MaxEntries) 577 return _URC_END_OF_STACK; 578 return _URC_NO_REASON; 579 }; 580 581 _Unwind_Backtrace( 582 [](_Unwind_Context *Context, void *Handler) { 583 return (*static_cast<decltype(HandleFrame) *>(Handler))(Context); 584 }, 585 static_cast<void *>(&HandleFrame)); 586 return std::max(Entries, 0); 587} 588#endif 589 590// In the case of a program crash or fault, print out a stack trace so that the 591// user has an indication of why and where we died. 592// 593// On glibc systems we have the 'backtrace' function, which works nicely, but 594// doesn't demangle symbols. 595void llvm::sys::PrintStackTrace(raw_ostream &OS, int Depth) { 596#if ENABLE_BACKTRACES 597 static void *StackTrace[256]; 598 int depth = 0; 599#if defined(HAVE_BACKTRACE) 600 // Use backtrace() to output a backtrace on Linux systems with glibc. 601 if (!depth) 602 depth = backtrace(StackTrace, static_cast<int>(std::size(StackTrace))); 603#endif 604#if defined(HAVE__UNWIND_BACKTRACE) 605 // Try _Unwind_Backtrace() if backtrace() failed. 606 if (!depth) 607 depth = 608 unwindBacktrace(StackTrace, static_cast<int>(std::size(StackTrace))); 609#endif 610 if (!depth) 611 return; 612 // If "Depth" is not provided by the caller, use the return value of 613 // backtrace() for printing a symbolized stack trace. 614 if (!Depth) 615 Depth = depth; 616 if (printSymbolizedStackTrace(Argv0, StackTrace, Depth, OS)) 617 return; 618 OS << "Stack dump without symbol names (ensure you have llvm-symbolizer in " 619 "your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point " 620 "to it):\n"; 621#if HAVE_DLFCN_H && HAVE_DLADDR 622 int width = 0; 623 for (int i = 0; i < depth; ++i) { 624 Dl_info dlinfo; 625 dladdr(StackTrace[i], &dlinfo); 626 const char *name = strrchr(dlinfo.dli_fname, '/'); 627 628 int nwidth; 629 if (!name) 630 nwidth = strlen(dlinfo.dli_fname); 631 else 632 nwidth = strlen(name) - 1; 633 634 if (nwidth > width) 635 width = nwidth; 636 } 637 638 for (int i = 0; i < depth; ++i) { 639 Dl_info dlinfo; 640 dladdr(StackTrace[i], &dlinfo); 641 642 OS << format("%-2d", i); 643 644 const char *name = strrchr(dlinfo.dli_fname, '/'); 645 if (!name) 646 OS << format(" %-*s", width, dlinfo.dli_fname); 647 else 648 OS << format(" %-*s", width, name + 1); 649 650 OS << format(" %#0*lx", (int)(sizeof(void *) * 2) + 2, 651 (unsigned long)StackTrace[i]); 652 653 if (dlinfo.dli_sname != nullptr) { 654 OS << ' '; 655 if (char *d = itaniumDemangle(dlinfo.dli_sname)) { 656 OS << d; 657 free(d); 658 } else { 659 OS << dlinfo.dli_sname; 660 } 661 662 OS << format(" + %tu", (static_cast<const char *>(StackTrace[i]) - 663 static_cast<const char *>(dlinfo.dli_saddr))); 664 } 665 OS << '\n'; 666 } 667#elif defined(HAVE_BACKTRACE) 668 backtrace_symbols_fd(StackTrace, Depth, STDERR_FILENO); 669#endif 670#endif 671} 672 673static void PrintStackTraceSignalHandler(void *) { 674 sys::PrintStackTrace(llvm::errs()); 675} 676 677void llvm::sys::DisableSystemDialogsOnCrash() {} 678 679/// When an error signal (such as SIGABRT or SIGSEGV) is delivered to the 680/// process, print a stack trace and then exit. 681void llvm::sys::PrintStackTraceOnErrorSignal(StringRef Argv0, 682 bool DisableCrashReporting) { 683 ::Argv0 = Argv0; 684 685 AddSignalHandler(PrintStackTraceSignalHandler, nullptr); 686 687#if defined(__APPLE__) && ENABLE_CRASH_OVERRIDES 688 // Environment variable to disable any kind of crash dialog. 689 if (DisableCrashReporting || getenv("LLVM_DISABLE_CRASH_REPORT")) { 690 mach_port_t self = mach_task_self(); 691 692 exception_mask_t mask = EXC_MASK_CRASH; 693 694 kern_return_t ret = task_set_exception_ports( 695 self, mask, MACH_PORT_NULL, 696 EXCEPTION_STATE_IDENTITY | MACH_EXCEPTION_CODES, THREAD_STATE_NONE); 697 (void)ret; 698 } 699#endif 700} 701