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