libsanitizer/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc

   1 //===-- sanitizer_symbolizer_posix_libcdep.cc -----------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is shared between AddressSanitizer and ThreadSanitizer
   9 // run-time libraries.
  10 // POSIX-specific implementation of symbolizer parts.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_platform.h"
  14 #if SANITIZER_POSIX
  15 #include "sanitizer_allocator_internal.h"
  16 #include "sanitizer_common.h"
  17 #include "sanitizer_file.h"
  18 #include "sanitizer_flags.h"
  19 #include "sanitizer_internal_defs.h"
  20 #include "sanitizer_linux.h"
  21 #include "sanitizer_placement_new.h"
  22 #include "sanitizer_posix.h"
  23 #include "sanitizer_procmaps.h"
  24 #include "sanitizer_symbolizer_internal.h"
  25 #include "sanitizer_symbolizer_libbacktrace.h"
  26 #include "sanitizer_symbolizer_mac.h"
  27
  28 #include <dlfcn.h>   // for dlsym()
  29 #include <errno.h>
  30 #include <stdint.h>
  31 #include <stdlib.h>
  32 #include <sys/wait.h>
  33 #include <unistd.h>
  34
  35 #if SANITIZER_MAC
  36 #include <util.h>  // for forkpty()
  37 #endif  // SANITIZER_MAC
  38
  39 // C++ demangling function, as required by Itanium C++ ABI. This is weak,
  40 // because we do not require a C++ ABI library to be linked to a program
  41 // using sanitizers; if it's not present, we'll just use the mangled name.
  42 namespace __cxxabiv1 {
  43   extern "C" SANITIZER_WEAK_ATTRIBUTE
  44   char *__cxa_demangle(const char *mangled, char *buffer,
  45                                   size_t *length, int *status);
  46 }
  47
  48 namespace __sanitizer {
  49
  50 // Attempts to demangle the name via __cxa_demangle from __cxxabiv1.
  51 const char *DemangleCXXABI(const char *name) {
  52   // FIXME: __cxa_demangle aggressively insists on allocating memory.
  53   // There's not much we can do about that, short of providing our
  54   // own demangler (libc++abi's implementation could be adapted so that
  55   // it does not allocate). For now, we just call it anyway, and we leak
  56   // the returned value.
  57   if (&__cxxabiv1::__cxa_demangle)
  58     if (const char *demangled_name =
  59           __cxxabiv1::__cxa_demangle(name, 0, 0, 0))
  60       return demangled_name;
  61
  62   return name;
  63 }
  64
  65 // As of now, there are no headers for the Swift runtime. Once they are
  66 // present, we will weakly link since we do not require Swift runtime to be
  67 // linked.
  68 typedef char *(*swift_demangle_ft)(const char *mangledName,
  69                                    size_t mangledNameLength, char *outputBuffer,
  70                                    size_t *outputBufferSize, uint32_t flags);
  71 static swift_demangle_ft swift_demangle_f;
  72
  73 // This must not happen lazily at symbolication time, because dlsym uses
  74 // malloc and thread-local storage, which is not a good thing to do during
  75 // symbolication.
  76 static void InitializeSwiftDemangler() {
  77   swift_demangle_f = (swift_demangle_ft)dlsym(RTLD_DEFAULT, "swift_demangle");
  78   (void)dlerror(); // Cleanup error message in case of failure
  79 }
  80
  81 // Attempts to demangle a Swift name. The demangler will return nullptr if a
  82 // non-Swift name is passed in.
  83 const char *DemangleSwift(const char *name) {
  84   if (!name) return nullptr;
  85
  86   // Check if we are dealing with a Swift mangled name first.
  87   if (name[0] != '_' || name[1] != 'T') {
  88     return nullptr;
  89   }
  90
  91   if (swift_demangle_f)
  92     return swift_demangle_f(name, internal_strlen(name), 0, 0, 0);
  93
  94   return nullptr;
  95 }
  96
  97 const char *DemangleSwiftAndCXX(const char *name) {
  98   if (!name) return nullptr;
  99   if (const char *swift_demangled_name = DemangleSwift(name))
 100     return swift_demangled_name;
 101   return DemangleCXXABI(name);
 102 }
 103
 104 static bool CreateTwoHighNumberedPipes(int *infd_, int *outfd_) {
 105   int *infd = NULL;
 106   int *outfd = NULL;
 107   // The client program may close its stdin and/or stdout and/or stderr
 108   // thus allowing socketpair to reuse file descriptors 0, 1 or 2.
 109   // In this case the communication between the forked processes may be
 110   // broken if either the parent or the child tries to close or duplicate
 111   // these descriptors. The loop below produces two pairs of file
 112   // descriptors, each greater than 2 (stderr).
 113   int sock_pair[5][2];
 114   for (int i = 0; i < 5; i++) {
 115     if (pipe(sock_pair[i]) == -1) {
 116       for (int j = 0; j < i; j++) {
 117         internal_close(sock_pair[j][0]);
 118         internal_close(sock_pair[j][1]);
 119       }
 120       return false;
 121     } else if (sock_pair[i][0] > 2 && sock_pair[i][1] > 2) {
 122       if (infd == NULL) {
 123         infd = sock_pair[i];
 124       } else {
 125         outfd = sock_pair[i];
 126         for (int j = 0; j < i; j++) {
 127           if (sock_pair[j] == infd) continue;
 128           internal_close(sock_pair[j][0]);
 129           internal_close(sock_pair[j][1]);
 130         }
 131         break;
 132       }
 133     }
 134   }
 135   CHECK(infd);
 136   CHECK(outfd);
 137   infd_[0] = infd[0];
 138   infd_[1] = infd[1];
 139   outfd_[0] = outfd[0];
 140   outfd_[1] = outfd[1];
 141   return true;
 142 }
 143
 144 bool SymbolizerProcess::StartSymbolizerSubprocess() {
 145   if (!FileExists(path_)) {
 146     if (!reported_invalid_path_) {
 147       Report("WARNING: invalid path to external symbolizer!\n");
 148       reported_invalid_path_ = true;
 149     }
 150     return false;
 151   }
 152
 153   int pid = -1;
 154
 155   int infd[2];
 156   internal_memset(&infd, 0, sizeof(infd));
 157   int outfd[2];
 158   internal_memset(&outfd, 0, sizeof(outfd));
 159   if (!CreateTwoHighNumberedPipes(infd, outfd)) {
 160     Report("WARNING: Can't create a socket pair to start "
 161            "external symbolizer (errno: %d)\n", errno);
 162     return false;
 163   }
 164
 165   if (use_forkpty_) {
 166 #if SANITIZER_MAC
 167     fd_t fd = kInvalidFd;
 168
 169     // forkpty redirects stdout and stderr into a single stream, so we would
 170     // receive error messages as standard replies. To avoid that, let's dup
 171     // stderr and restore it in the child.
 172     int saved_stderr = dup(STDERR_FILENO);
 173     CHECK_GE(saved_stderr, 0);
 174
 175     // We only need one pipe, for stdin of the child.
 176     close(outfd[0]);
 177     close(outfd[1]);
 178
 179     // Use forkpty to disable buffering in the new terminal.
 180     pid = internal_forkpty(&fd);
 181     if (pid == -1) {
 182       // forkpty() failed.
 183       Report("WARNING: failed to fork external symbolizer (errno: %d)\n",
 184              errno);
 185       return false;
 186     } else if (pid == 0) {
 187       // Child subprocess.
 188
 189       // infd[0] is the child's reading end.
 190       close(infd[1]);
 191
 192       // Set up stdin to read from the pipe.
 193       CHECK_GE(dup2(infd[0], STDIN_FILENO), 0);
 194       close(infd[0]);
 195
 196       // Restore stderr.
 197       CHECK_GE(dup2(saved_stderr, STDERR_FILENO), 0);
 198       close(saved_stderr);
 199
 200       const char *argv[kArgVMax];
 201       GetArgV(path_, argv);
 202       execv(path_, const_cast<char **>(&argv[0]));
 203       internal__exit(1);
 204     }
 205
 206     // Input for the child, infd[1] is our writing end.
 207     output_fd_ = infd[1];
 208     close(infd[0]);
 209
 210     // Continue execution in parent process.
 211     input_fd_ = fd;
 212
 213     close(saved_stderr);
 214
 215     // Disable echo in the new terminal, disable CR.
 216     struct termios termflags;
 217     tcgetattr(fd, &termflags);
 218     termflags.c_oflag &= ~ONLCR;
 219     termflags.c_lflag &= ~ECHO;
 220     tcsetattr(fd, TCSANOW, &termflags);
 221 #else  // SANITIZER_MAC
 222     UNIMPLEMENTED();
 223 #endif  // SANITIZER_MAC
 224   } else {
 225     const char *argv[kArgVMax];
 226     GetArgV(path_, argv);
 227     pid = StartSubprocess(path_, argv, /* stdin */ outfd[0],
 228                           /* stdout */ infd[1]);
 229     if (pid < 0) {
 230       internal_close(infd[0]);
 231       internal_close(outfd[1]);
 232       return false;
 233     }
 234
 235     input_fd_ = infd[0];
 236     output_fd_ = outfd[1];
 237   }
 238
 239   CHECK_GT(pid, 0);
 240
 241   // Check that symbolizer subprocess started successfully.
 242   SleepForMillis(kSymbolizerStartupTimeMillis);
 243   if (!IsProcessRunning(pid)) {
 244     // Either waitpid failed, or child has already exited.
 245     Report("WARNING: external symbolizer didn't start up correctly!\n");
 246     return false;
 247   }
 248
 249   return true;
 250 }
 251
 252 class Addr2LineProcess : public SymbolizerProcess {
 253  public:
 254   Addr2LineProcess(const char *path, const char *module_name)
 255       : SymbolizerProcess(path), module_name_(internal_strdup(module_name)) {}
 256
 257   const char *module_name() const { return module_name_; }
 258
 259  private:
 260   void GetArgV(const char *path_to_binary,
 261                const char *(&argv)[kArgVMax]) const override {
 262     int i = 0;
 263     argv[i++] = path_to_binary;
 264     argv[i++] = "-iCfe";
 265     argv[i++] = module_name_;
 266     argv[i++] = nullptr;
 267   }
 268
 269   bool ReachedEndOfOutput(const char *buffer, uptr length) const override;
 270
 271   bool ReadFromSymbolizer(char *buffer, uptr max_length) override {
 272     if (!SymbolizerProcess::ReadFromSymbolizer(buffer, max_length))
 273       return false;
 274     // The returned buffer is empty when output is valid, but exceeds
 275     // max_length.
 276     if (*buffer == '\0')
 277       return true;
 278     // We should cut out output_terminator_ at the end of given buffer,
 279     // appended by addr2line to mark the end of its meaningful output.
 280     // We cannot scan buffer from it's beginning, because it is legal for it
 281     // to start with output_terminator_ in case given offset is invalid. So,
 282     // scanning from second character.
 283     char *garbage = internal_strstr(buffer + 1, output_terminator_);
 284     // This should never be NULL since buffer must end up with
 285     // output_terminator_.
 286     CHECK(garbage);
 287     // Trim the buffer.
 288     garbage[0] = '\0';
 289     return true;
 290   }
 291
 292   const char *module_name_;  // Owned, leaked.
 293   static const char output_terminator_[];
 294 };
 295
 296 const char Addr2LineProcess::output_terminator_[] = "??\n??:0\n";
 297
 298 bool Addr2LineProcess::ReachedEndOfOutput(const char *buffer,
 299                                           uptr length) const {
 300   const size_t kTerminatorLen = sizeof(output_terminator_) - 1;
 301   // Skip, if we read just kTerminatorLen bytes, because Addr2Line output
 302   // should consist at least of two pairs of lines:
 303   // 1. First one, corresponding to given offset to be symbolized
 304   // (may be equal to output_terminator_, if offset is not valid).
 305   // 2. Second one for output_terminator_, itself to mark the end of output.
 306   if (length <= kTerminatorLen) return false;
 307   // Addr2Line output should end up with output_terminator_.
 308   return !internal_memcmp(buffer + length - kTerminatorLen,
 309                           output_terminator_, kTerminatorLen);
 310 }
 311
 312 class Addr2LinePool : public SymbolizerTool {
 313  public:
 314   explicit Addr2LinePool(const char *addr2line_path,
 315                          LowLevelAllocator *allocator)
 316       : addr2line_path_(addr2line_path), allocator_(allocator) {
 317     addr2line_pool_.reserve(16);
 318   }
 319
 320   bool SymbolizePC(uptr addr, SymbolizedStack *stack) override {
 321     if (const char *buf =
 322             SendCommand(stack->info.module, stack->info.module_offset)) {
 323       ParseSymbolizePCOutput(buf, stack);
 324       return true;
 325     }
 326     return false;
 327   }
 328
 329   bool SymbolizeData(uptr addr, DataInfo *info) override {
 330     return false;
 331   }
 332
 333  private:
 334   const char *SendCommand(const char *module_name, uptr module_offset) {
 335     Addr2LineProcess *addr2line = 0;
 336     for (uptr i = 0; i < addr2line_pool_.size(); ++i) {
 337       if (0 ==
 338           internal_strcmp(module_name, addr2line_pool_[i]->module_name())) {
 339         addr2line = addr2line_pool_[i];
 340         break;
 341       }
 342     }
 343     if (!addr2line) {
 344       addr2line =
 345           new(*allocator_) Addr2LineProcess(addr2line_path_, module_name);
 346       addr2line_pool_.push_back(addr2line);
 347     }
 348     CHECK_EQ(0, internal_strcmp(module_name, addr2line->module_name()));
 349     char buffer[kBufferSize];
 350     internal_snprintf(buffer, kBufferSize, "0x%zx\n0x%zx\n",
 351                       module_offset, dummy_address_);
 352     return addr2line->SendCommand(buffer);
 353   }
 354
 355   static const uptr kBufferSize = 64;
 356   const char *addr2line_path_;
 357   LowLevelAllocator *allocator_;
 358   InternalMmapVector<Addr2LineProcess*> addr2line_pool_;
 359   static const uptr dummy_address_ =
 360       FIRST_32_SECOND_64(UINT32_MAX, UINT64_MAX);
 361 };
 362
 363 #if SANITIZER_SUPPORTS_WEAK_HOOKS
 364 extern "C" {
 365 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 366 bool __sanitizer_symbolize_code(const char *ModuleName, u64 ModuleOffset,
 367                                 char *Buffer, int MaxLength);
 368 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 369 bool __sanitizer_symbolize_data(const char *ModuleName, u64 ModuleOffset,
 370                                 char *Buffer, int MaxLength);
 371 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 372 void __sanitizer_symbolize_flush();
 373 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 374 int __sanitizer_symbolize_demangle(const char *Name, char *Buffer,
 375                                    int MaxLength);
 376 }  // extern "C"
 377
 378 class InternalSymbolizer : public SymbolizerTool {
 379  public:
 380   static InternalSymbolizer *get(LowLevelAllocator *alloc) {
 381     if (__sanitizer_symbolize_code != 0 &&
 382         __sanitizer_symbolize_data != 0) {
 383       return new(*alloc) InternalSymbolizer();
 384     }
 385     return 0;
 386   }
 387
 388   bool SymbolizePC(uptr addr, SymbolizedStack *stack) override {
 389     bool result = __sanitizer_symbolize_code(
 390         stack->info.module, stack->info.module_offset, buffer_, kBufferSize);
 391     if (result) ParseSymbolizePCOutput(buffer_, stack);
 392     return result;
 393   }
 394
 395   bool SymbolizeData(uptr addr, DataInfo *info) override {
 396     bool result = __sanitizer_symbolize_data(info->module, info->module_offset,
 397                                              buffer_, kBufferSize);
 398     if (result) {
 399       ParseSymbolizeDataOutput(buffer_, info);
 400       info->start += (addr - info->module_offset);  // Add the base address.
 401     }
 402     return result;
 403   }
 404
 405   void Flush() override {
 406     if (__sanitizer_symbolize_flush)
 407       __sanitizer_symbolize_flush();
 408   }
 409
 410   const char *Demangle(const char *name) override {
 411     if (__sanitizer_symbolize_demangle) {
 412       for (uptr res_length = 1024;
 413            res_length <= InternalSizeClassMap::kMaxSize;) {
 414         char *res_buff = static_cast<char*>(InternalAlloc(res_length));
 415         uptr req_length =
 416             __sanitizer_symbolize_demangle(name, res_buff, res_length);
 417         if (req_length > res_length) {
 418           res_length = req_length + 1;
 419           InternalFree(res_buff);
 420           continue;
 421         }
 422         return res_buff;
 423       }
 424     }
 425     return name;
 426   }
 427
 428  private:
 429   InternalSymbolizer() { }
 430
 431   static const int kBufferSize = 16 * 1024;
 432   char buffer_[kBufferSize];
 433 };
 434 #else  // SANITIZER_SUPPORTS_WEAK_HOOKS
 435
 436 class InternalSymbolizer : public SymbolizerTool {
 437  public:
 438   static InternalSymbolizer *get(LowLevelAllocator *alloc) { return 0; }
 439 };
 440
 441 #endif  // SANITIZER_SUPPORTS_WEAK_HOOKS
 442
 443 const char *Symbolizer::PlatformDemangle(const char *name) {
 444   return DemangleSwiftAndCXX(name);
 445 }
 446
 447 static SymbolizerTool *ChooseExternalSymbolizer(LowLevelAllocator *allocator) {
 448   const char *path = common_flags()->external_symbolizer_path;
 449   const char *binary_name = path ? StripModuleName(path) : "";
 450   if (path && path[0] == '\0') {
 451     VReport(2, "External symbolizer is explicitly disabled.\n");
 452     return nullptr;
 453   } else if (!internal_strcmp(binary_name, "llvm-symbolizer")) {
 454     VReport(2, "Using llvm-symbolizer at user-specified path: %s\n", path);
 455     return new(*allocator) LLVMSymbolizer(path, allocator);
 456   } else if (!internal_strcmp(binary_name, "atos")) {
 457 #if SANITIZER_MAC
 458     VReport(2, "Using atos at user-specified path: %s\n", path);
 459     return new(*allocator) AtosSymbolizer(path, allocator);
 460 #else  // SANITIZER_MAC
 461     Report("ERROR: Using `atos` is only supported on Darwin.\n");
 462     Die();
 463 #endif  // SANITIZER_MAC
 464   } else if (!internal_strcmp(binary_name, "addr2line")) {
 465     VReport(2, "Using addr2line at user-specified path: %s\n", path);
 466     return new(*allocator) Addr2LinePool(path, allocator);
 467   } else if (path) {
 468     Report("ERROR: External symbolizer path is set to '%s' which isn't "
 469            "a known symbolizer. Please set the path to the llvm-symbolizer "
 470            "binary or other known tool.\n", path);
 471     Die();
 472   }
 473
 474   // Otherwise symbolizer program is unknown, let's search $PATH
 475   CHECK(path == nullptr);
 476 #if SANITIZER_MAC
 477   if (const char *found_path = FindPathToBinary("atos")) {
 478     VReport(2, "Using atos found at: %s\n", found_path);
 479     return new(*allocator) AtosSymbolizer(found_path, allocator);
 480   }
 481 #endif  // SANITIZER_MAC
 482   if (const char *found_path = FindPathToBinary("llvm-symbolizer")) {
 483     VReport(2, "Using llvm-symbolizer found at: %s\n", found_path);
 484     return new(*allocator) LLVMSymbolizer(found_path, allocator);
 485   }
 486   if (common_flags()->allow_addr2line) {
 487     if (const char *found_path = FindPathToBinary("addr2line")) {
 488       VReport(2, "Using addr2line found at: %s\n", found_path);
 489       return new(*allocator) Addr2LinePool(found_path, allocator);
 490     }
 491   }
 492   return nullptr;
 493 }
 494
 495 static void ChooseSymbolizerTools(IntrusiveList<SymbolizerTool> *list,
 496                                   LowLevelAllocator *allocator) {
 497   if (!common_flags()->symbolize) {
 498     VReport(2, "Symbolizer is disabled.\n");
 499     return;
 500   }
 501   if (IsAllocatorOutOfMemory()) {
 502     VReport(2, "Cannot use internal symbolizer: out of memory\n");
 503   } else if (SymbolizerTool *tool = InternalSymbolizer::get(allocator)) {
 504     VReport(2, "Using internal symbolizer.\n");
 505     list->push_back(tool);
 506     return;
 507   }
 508   if (SymbolizerTool *tool = LibbacktraceSymbolizer::get(allocator)) {
 509     VReport(2, "Using libbacktrace symbolizer.\n");
 510     list->push_back(tool);
 511     return;
 512   }
 513
 514   if (SymbolizerTool *tool = ChooseExternalSymbolizer(allocator)) {
 515     list->push_back(tool);
 516   }
 517
 518 #if SANITIZER_MAC
 519   VReport(2, "Using dladdr symbolizer.\n");
 520   list->push_back(new(*allocator) DlAddrSymbolizer());
 521 #endif  // SANITIZER_MAC
 522 }
 523
 524 Symbolizer *Symbolizer::PlatformInit() {
 525   IntrusiveList<SymbolizerTool> list;
 526   list.clear();
 527   ChooseSymbolizerTools(&list, &symbolizer_allocator_);
 528   return new(symbolizer_allocator_) Symbolizer(list);
 529 }
 530
 531 void Symbolizer::LateInitialize() {
 532   Symbolizer::GetOrInit();
 533   InitializeSwiftDemangler();
 534 }
 535
 536 }  // namespace __sanitizer
 537
 538 #endif  // SANITIZER_POSIX