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_flags.h"
  18 #include "sanitizer_internal_defs.h"
  19 #include "sanitizer_linux.h"
  20 #include "sanitizer_placement_new.h"
  21 #include "sanitizer_posix.h"
  22 #include "sanitizer_procmaps.h"
  23 #include "sanitizer_symbolizer_internal.h"
  24 #include "sanitizer_symbolizer_libbacktrace.h"
  25 #include "sanitizer_symbolizer_mac.h"
  26
  27 #include <errno.h>
  28 #include <stdlib.h>
  29 #include <sys/wait.h>
  30 #include <unistd.h>
  31
  32 #if SANITIZER_MAC
  33 #include <util.h>  // for forkpty()
  34 #endif  // SANITIZER_MAC
  35
  36 // C++ demangling function, as required by Itanium C++ ABI. This is weak,
  37 // because we do not require a C++ ABI library to be linked to a program
  38 // using sanitizers; if it's not present, we'll just use the mangled name.
  39 namespace __cxxabiv1 {
  40   extern "C" SANITIZER_WEAK_ATTRIBUTE
  41   char *__cxa_demangle(const char *mangled, char *buffer,
  42                                   size_t *length, int *status);
  43 }
  44
  45 namespace __sanitizer {
  46
  47 // Attempts to demangle the name via __cxa_demangle from __cxxabiv1.
  48 const char *DemangleCXXABI(const char *name) {
  49   // FIXME: __cxa_demangle aggressively insists on allocating memory.
  50   // There's not much we can do about that, short of providing our
  51   // own demangler (libc++abi's implementation could be adapted so that
  52   // it does not allocate). For now, we just call it anyway, and we leak
  53   // the returned value.
  54   if (__cxxabiv1::__cxa_demangle)
  55     if (const char *demangled_name =
  56           __cxxabiv1::__cxa_demangle(name, 0, 0, 0))
  57       return demangled_name;
  58
  59   return name;
  60 }
  61
  62 bool SymbolizerProcess::StartSymbolizerSubprocess() {
  63   if (!FileExists(path_)) {
  64     if (!reported_invalid_path_) {
  65       Report("WARNING: invalid path to external symbolizer!\n");
  66       reported_invalid_path_ = true;
  67     }
  68     return false;
  69   }
  70
  71   int pid;
  72   if (use_forkpty_) {
  73 #if SANITIZER_MAC
  74     fd_t fd = kInvalidFd;
  75     // Use forkpty to disable buffering in the new terminal.
  76     pid = forkpty(&fd, 0, 0, 0);
  77     if (pid == -1) {
  78       // forkpty() failed.
  79       Report("WARNING: failed to fork external symbolizer (errno: %d)\n",
  80              errno);
  81       return false;
  82     } else if (pid == 0) {
  83       // Child subprocess.
  84       const char *argv[kArgVMax];
  85       GetArgV(path_, argv);
  86       execv(path_, const_cast<char **>(&argv[0]));
  87       internal__exit(1);
  88     }
  89
  90     // Continue execution in parent process.
  91     input_fd_ = output_fd_ = fd;
  92
  93     // Disable echo in the new terminal, disable CR.
  94     struct termios termflags;
  95     tcgetattr(fd, &termflags);
  96     termflags.c_oflag &= ~ONLCR;
  97     termflags.c_lflag &= ~ECHO;
  98     tcsetattr(fd, TCSANOW, &termflags);
  99 #else  // SANITIZER_MAC
 100     UNIMPLEMENTED();
 101 #endif  // SANITIZER_MAC
 102   } else {
 103     int *infd = NULL;
 104     int *outfd = NULL;
 105     // The client program may close its stdin and/or stdout and/or stderr
 106     // thus allowing socketpair to reuse file descriptors 0, 1 or 2.
 107     // In this case the communication between the forked processes may be
 108     // broken if either the parent or the child tries to close or duplicate
 109     // these descriptors. The loop below produces two pairs of file
 110     // descriptors, each greater than 2 (stderr).
 111     int sock_pair[5][2];
 112     for (int i = 0; i < 5; i++) {
 113       if (pipe(sock_pair[i]) == -1) {
 114         for (int j = 0; j < i; j++) {
 115           internal_close(sock_pair[j][0]);
 116           internal_close(sock_pair[j][1]);
 117         }
 118         Report("WARNING: Can't create a socket pair to start "
 119                "external symbolizer (errno: %d)\n", errno);
 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
 138     // Real fork() may call user callbacks registered with pthread_atfork().
 139     pid = internal_fork();
 140     if (pid == -1) {
 141       // Fork() failed.
 142       internal_close(infd[0]);
 143       internal_close(infd[1]);
 144       internal_close(outfd[0]);
 145       internal_close(outfd[1]);
 146       Report("WARNING: failed to fork external symbolizer "
 147              " (errno: %d)\n", errno);
 148       return false;
 149     } else if (pid == 0) {
 150       // Child subprocess.
 151       internal_close(STDOUT_FILENO);
 152       internal_close(STDIN_FILENO);
 153       internal_dup2(outfd[0], STDIN_FILENO);
 154       internal_dup2(infd[1], STDOUT_FILENO);
 155       internal_close(outfd[0]);
 156       internal_close(outfd[1]);
 157       internal_close(infd[0]);
 158       internal_close(infd[1]);
 159       for (int fd = sysconf(_SC_OPEN_MAX); fd > 2; fd--)
 160         internal_close(fd);
 161       const char *argv[kArgVMax];
 162       GetArgV(path_, argv);
 163       execv(path_, const_cast<char **>(&argv[0]));
 164       internal__exit(1);
 165     }
 166
 167     // Continue execution in parent process.
 168     internal_close(outfd[0]);
 169     internal_close(infd[1]);
 170     input_fd_ = infd[0];
 171     output_fd_ = outfd[1];
 172   }
 173
 174   // Check that symbolizer subprocess started successfully.
 175   int pid_status;
 176   SleepForMillis(kSymbolizerStartupTimeMillis);
 177   int exited_pid = waitpid(pid, &pid_status, WNOHANG);
 178   if (exited_pid != 0) {
 179     // Either waitpid failed, or child has already exited.
 180     Report("WARNING: external symbolizer didn't start up correctly!\n");
 181     return false;
 182   }
 183
 184   return true;
 185 }
 186
 187 class Addr2LineProcess : public SymbolizerProcess {
 188  public:
 189   Addr2LineProcess(const char *path, const char *module_name)
 190       : SymbolizerProcess(path), module_name_(internal_strdup(module_name)) {}
 191
 192   const char *module_name() const { return module_name_; }
 193
 194  private:
 195   void GetArgV(const char *path_to_binary,
 196                const char *(&argv)[kArgVMax]) const override {
 197     int i = 0;
 198     argv[i++] = path_to_binary;
 199     argv[i++] = "-iCfe";
 200     argv[i++] = module_name_;
 201     argv[i++] = nullptr;
 202   }
 203
 204   bool ReachedEndOfOutput(const char *buffer, uptr length) const override;
 205
 206   bool ReadFromSymbolizer(char *buffer, uptr max_length) override {
 207     if (!SymbolizerProcess::ReadFromSymbolizer(buffer, max_length))
 208       return false;
 209     // We should cut out output_terminator_ at the end of given buffer,
 210     // appended by addr2line to mark the end of its meaningful output.
 211     // We cannot scan buffer from it's beginning, because it is legal for it
 212     // to start with output_terminator_ in case given offset is invalid. So,
 213     // scanning from second character.
 214     char *garbage = internal_strstr(buffer + 1, output_terminator_);
 215     // This should never be NULL since buffer must end up with
 216     // output_terminator_.
 217     CHECK(garbage);
 218     // Trim the buffer.
 219     garbage[0] = '\0';
 220     return true;
 221   }
 222
 223   const char *module_name_;  // Owned, leaked.
 224   static const char output_terminator_[];
 225 };
 226
 227 const char Addr2LineProcess::output_terminator_[] = "??\n??:0\n";
 228
 229 bool Addr2LineProcess::ReachedEndOfOutput(const char *buffer,
 230                                           uptr length) const {
 231   const size_t kTerminatorLen = sizeof(output_terminator_) - 1;
 232   // Skip, if we read just kTerminatorLen bytes, because Addr2Line output
 233   // should consist at least of two pairs of lines:
 234   // 1. First one, corresponding to given offset to be symbolized
 235   // (may be equal to output_terminator_, if offset is not valid).
 236   // 2. Second one for output_terminator_, itself to mark the end of output.
 237   if (length <= kTerminatorLen) return false;
 238   // Addr2Line output should end up with output_terminator_.
 239   return !internal_memcmp(buffer + length - kTerminatorLen,
 240                           output_terminator_, kTerminatorLen);
 241 }
 242
 243 class Addr2LinePool : public SymbolizerTool {
 244  public:
 245   explicit Addr2LinePool(const char *addr2line_path,
 246                          LowLevelAllocator *allocator)
 247       : addr2line_path_(addr2line_path), allocator_(allocator),
 248         addr2line_pool_(16) {}
 249
 250   bool SymbolizePC(uptr addr, SymbolizedStack *stack) override {
 251     if (const char *buf =
 252             SendCommand(stack->info.module, stack->info.module_offset)) {
 253       ParseSymbolizePCOutput(buf, stack);
 254       return true;
 255     }
 256     return false;
 257   }
 258
 259   bool SymbolizeData(uptr addr, DataInfo *info) override {
 260     return false;
 261   }
 262
 263  private:
 264   const char *SendCommand(const char *module_name, uptr module_offset) {
 265     Addr2LineProcess *addr2line = 0;
 266     for (uptr i = 0; i < addr2line_pool_.size(); ++i) {
 267       if (0 ==
 268           internal_strcmp(module_name, addr2line_pool_[i]->module_name())) {
 269         addr2line = addr2line_pool_[i];
 270         break;
 271       }
 272     }
 273     if (!addr2line) {
 274       addr2line =
 275           new(*allocator_) Addr2LineProcess(addr2line_path_, module_name);
 276       addr2line_pool_.push_back(addr2line);
 277     }
 278     CHECK_EQ(0, internal_strcmp(module_name, addr2line->module_name()));
 279     char buffer[kBufferSize];
 280     internal_snprintf(buffer, kBufferSize, "0x%zx\n0x%zx\n",
 281                       module_offset, dummy_address_);
 282     return addr2line->SendCommand(buffer);
 283   }
 284
 285   static const uptr kBufferSize = 64;
 286   const char *addr2line_path_;
 287   LowLevelAllocator *allocator_;
 288   InternalMmapVector<Addr2LineProcess*> addr2line_pool_;
 289   static const uptr dummy_address_ =
 290       FIRST_32_SECOND_64(UINT32_MAX, UINT64_MAX);
 291 };
 292
 293 #if SANITIZER_SUPPORTS_WEAK_HOOKS
 294 extern "C" {
 295 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 296 bool __sanitizer_symbolize_code(const char *ModuleName, u64 ModuleOffset,
 297                                 char *Buffer, int MaxLength);
 298 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 299 bool __sanitizer_symbolize_data(const char *ModuleName, u64 ModuleOffset,
 300                                 char *Buffer, int MaxLength);
 301 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 302 void __sanitizer_symbolize_flush();
 303 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 304 int __sanitizer_symbolize_demangle(const char *Name, char *Buffer,
 305                                    int MaxLength);
 306 }  // extern "C"
 307
 308 class InternalSymbolizer : public SymbolizerTool {
 309  public:
 310   static InternalSymbolizer *get(LowLevelAllocator *alloc) {
 311     if (__sanitizer_symbolize_code != 0 &&
 312         __sanitizer_symbolize_data != 0) {
 313       return new(*alloc) InternalSymbolizer();
 314     }
 315     return 0;
 316   }
 317
 318   bool SymbolizePC(uptr addr, SymbolizedStack *stack) override {
 319     bool result = __sanitizer_symbolize_code(
 320         stack->info.module, stack->info.module_offset, buffer_, kBufferSize);
 321     if (result) ParseSymbolizePCOutput(buffer_, stack);
 322     return result;
 323   }
 324
 325   bool SymbolizeData(uptr addr, DataInfo *info) override {
 326     bool result = __sanitizer_symbolize_data(info->module, info->module_offset,
 327                                              buffer_, kBufferSize);
 328     if (result) {
 329       ParseSymbolizeDataOutput(buffer_, info);
 330       info->start += (addr - info->module_offset);  // Add the base address.
 331     }
 332     return result;
 333   }
 334
 335   void Flush() override {
 336     if (__sanitizer_symbolize_flush)
 337       __sanitizer_symbolize_flush();
 338   }
 339
 340   const char *Demangle(const char *name) override {
 341     if (__sanitizer_symbolize_demangle) {
 342       for (uptr res_length = 1024;
 343            res_length <= InternalSizeClassMap::kMaxSize;) {
 344         char *res_buff = static_cast<char*>(InternalAlloc(res_length));
 345         uptr req_length =
 346             __sanitizer_symbolize_demangle(name, res_buff, res_length);
 347         if (req_length > res_length) {
 348           res_length = req_length + 1;
 349           InternalFree(res_buff);
 350           continue;
 351         }
 352         return res_buff;
 353       }
 354     }
 355     return name;
 356   }
 357
 358  private:
 359   InternalSymbolizer() { }
 360
 361   static const int kBufferSize = 16 * 1024;
 362   static const int kMaxDemangledNameSize = 1024;
 363   char buffer_[kBufferSize];
 364 };
 365 #else  // SANITIZER_SUPPORTS_WEAK_HOOKS
 366
 367 class InternalSymbolizer : public SymbolizerTool {
 368  public:
 369   static InternalSymbolizer *get(LowLevelAllocator *alloc) { return 0; }
 370 };
 371
 372 #endif  // SANITIZER_SUPPORTS_WEAK_HOOKS
 373
 374 const char *Symbolizer::PlatformDemangle(const char *name) {
 375   return DemangleCXXABI(name);
 376 }
 377
 378 void Symbolizer::PlatformPrepareForSandboxing() {}
 379
 380 static SymbolizerTool *ChooseExternalSymbolizer(LowLevelAllocator *allocator) {
 381   const char *path = common_flags()->external_symbolizer_path;
 382   const char *binary_name = path ? StripModuleName(path) : "";
 383   if (path && path[0] == '\0') {
 384     VReport(2, "External symbolizer is explicitly disabled.\n");
 385     return nullptr;
 386   } else if (!internal_strcmp(binary_name, "llvm-symbolizer")) {
 387     VReport(2, "Using llvm-symbolizer at user-specified path: %s\n", path);
 388     return new(*allocator) LLVMSymbolizer(path, allocator);
 389   } else if (!internal_strcmp(binary_name, "atos")) {
 390 #if SANITIZER_MAC
 391     VReport(2, "Using atos at user-specified path: %s\n", path);
 392     return new(*allocator) AtosSymbolizer(path, allocator);
 393 #else  // SANITIZER_MAC
 394     Report("ERROR: Using `atos` is only supported on Darwin.\n");
 395     Die();
 396 #endif  // SANITIZER_MAC
 397   } else if (!internal_strcmp(binary_name, "addr2line")) {
 398     VReport(2, "Using addr2line at user-specified path: %s\n", path);
 399     return new(*allocator) Addr2LinePool(path, allocator);
 400   } else if (path) {
 401     Report("ERROR: External symbolizer path is set to '%s' which isn't "
 402            "a known symbolizer. Please set the path to the llvm-symbolizer "
 403            "binary or other known tool.\n", path);
 404     Die();
 405   }
 406
 407   // Otherwise symbolizer program is unknown, let's search $PATH
 408   CHECK(path == nullptr);
 409   if (const char *found_path = FindPathToBinary("llvm-symbolizer")) {
 410     VReport(2, "Using llvm-symbolizer found at: %s\n", found_path);
 411     return new(*allocator) LLVMSymbolizer(found_path, allocator);
 412   }
 413 #if SANITIZER_MAC
 414   if (const char *found_path = FindPathToBinary("atos")) {
 415     VReport(2, "Using atos found at: %s\n", found_path);
 416     return new(*allocator) AtosSymbolizer(found_path, allocator);
 417   }
 418 #endif  // SANITIZER_MAC
 419   if (common_flags()->allow_addr2line) {
 420     if (const char *found_path = FindPathToBinary("addr2line")) {
 421       VReport(2, "Using addr2line found at: %s\n", found_path);
 422       return new(*allocator) Addr2LinePool(found_path, allocator);
 423     }
 424   }
 425   return nullptr;
 426 }
 427
 428 static void ChooseSymbolizerTools(IntrusiveList<SymbolizerTool> *list,
 429                                   LowLevelAllocator *allocator) {
 430   if (!common_flags()->symbolize) {
 431     VReport(2, "Symbolizer is disabled.\n");
 432     return;
 433   }
 434   if (SymbolizerTool *tool = InternalSymbolizer::get(allocator)) {
 435     VReport(2, "Using internal symbolizer.\n");
 436     list->push_back(tool);
 437     return;
 438   }
 439   if (SymbolizerTool *tool = LibbacktraceSymbolizer::get(allocator)) {
 440     VReport(2, "Using libbacktrace symbolizer.\n");
 441     list->push_back(tool);
 442     return;
 443   }
 444
 445   if (SymbolizerTool *tool = ChooseExternalSymbolizer(allocator)) {
 446     list->push_back(tool);
 447   }
 448
 449 #if SANITIZER_MAC
 450   VReport(2, "Using dladdr symbolizer.\n");
 451   list->push_back(new(*allocator) DlAddrSymbolizer());
 452 #endif  // SANITIZER_MAC
 453
 454   if (list->size() == 0) {
 455     Report("WARNING: no internal or external symbolizer found.\n");
 456   }
 457 }
 458
 459 Symbolizer *Symbolizer::PlatformInit() {
 460   IntrusiveList<SymbolizerTool> list;
 461   list.clear();
 462   ChooseSymbolizerTools(&list, &symbolizer_allocator_);
 463   return new(symbolizer_allocator_) Symbolizer(list);
 464 }
 465
 466 }  // namespace __sanitizer
 467
 468 #endif  // SANITIZER_POSIX