1 //===-- sanitizer_symbolizer_mac.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 various sanitizers' runtime libraries. 10 // 11 // Implementation of Mac-specific "atos" symbolizer. 12 //===----------------------------------------------------------------------===// 13 14 #include "sanitizer_platform.h" 15 #if SANITIZER_MAC 16 17 #include "sanitizer_allocator_internal.h" 18 #include "sanitizer_mac.h" 19 #include "sanitizer_symbolizer_mac.h" 20 21 #include <dlfcn.h> 22 #include <errno.h> 23 #include <mach/mach.h> 24 #include <stdlib.h> 25 #include <sys/wait.h> 26 #include <unistd.h> 27 #include <util.h> 28 29 namespace __sanitizer { 30 31 bool DlAddrSymbolizer::SymbolizePC(uptr addr, SymbolizedStack *stack) { 32 Dl_info info; 33 int result = dladdr((const void *)addr, &info); 34 if (!result) return false; 35 36 // Compute offset if possible. `dladdr()` doesn't always ensure that `addr >= 37 // sym_addr` so only compute the offset when this holds. Failure to find the 38 // function offset is not treated as a failure because it might still be 39 // possible to get the symbol name. 40 uptr sym_addr = reinterpret_cast<uptr>(info.dli_saddr); 41 if (addr >= sym_addr) { 42 stack->info.function_offset = addr - sym_addr; 43 } 44 45 const char *demangled = DemangleSwiftAndCXX(info.dli_sname); 46 if (!demangled) return false; 47 stack->info.function = internal_strdup(demangled); 48 return true; 49 } 50 51 bool DlAddrSymbolizer::SymbolizeData(uptr addr, DataInfo *datainfo) { 52 Dl_info info; 53 int result = dladdr((const void *)addr, &info); 54 if (!result) return false; 55 const char *demangled = DemangleSwiftAndCXX(info.dli_sname); 56 datainfo->name = internal_strdup(demangled); 57 datainfo->start = (uptr)info.dli_saddr; 58 return true; 59 } 60 61 #define K_ATOS_ENV_VAR "__check_mach_ports_lookup" 62 63 // This cannot live in `AtosSymbolizerProcess` because instances of that object 64 // are allocated by the internal allocator which under ASan is poisoned with 65 // kAsanInternalHeapMagic. 66 static char kAtosMachPortEnvEntry[] = K_ATOS_ENV_VAR "=000000000000000"; 67 68 class AtosSymbolizerProcess final : public SymbolizerProcess { 69 public: 70 explicit AtosSymbolizerProcess(const char *path) 71 : SymbolizerProcess(path, /*use_posix_spawn*/ true) { 72 pid_str_[0] = '\0'; 73 } 74 75 void LateInitialize() { 76 if (SANITIZER_IOSSIM) { 77 // `putenv()` may call malloc/realloc so it is only safe to do this 78 // during LateInitialize() or later (i.e. we can't do this in the 79 // constructor). We also can't do this in `StartSymbolizerSubprocess()` 80 // because in TSan we switch allocators when we're symbolizing. 81 // We use `putenv()` rather than `setenv()` so that we can later directly 82 // write into the storage without LibC getting involved to change what the 83 // variable is set to 84 int result = putenv(kAtosMachPortEnvEntry); 85 CHECK_EQ(result, 0); 86 } 87 } 88 89 private: 90 bool StartSymbolizerSubprocess() override { 91 // Configure sandbox before starting atos process. 92 93 // Put the string command line argument in the object so that it outlives 94 // the call to GetArgV. 95 internal_snprintf(pid_str_, sizeof(pid_str_), "%d", internal_getpid()); 96 97 if (SANITIZER_IOSSIM) { 98 // `atos` in the simulator is restricted in its ability to retrieve the 99 // task port for the target process (us) so we need to do extra work 100 // to pass our task port to it. 101 mach_port_t ports[]{mach_task_self()}; 102 kern_return_t ret = 103 mach_ports_register(mach_task_self(), ports, /*count=*/1); 104 CHECK_EQ(ret, KERN_SUCCESS); 105 106 // Set environment variable that signals to `atos` that it should look 107 // for our task port. We can't call `setenv()` here because it might call 108 // malloc/realloc. To avoid that we instead update the 109 // `mach_port_env_var_entry_` variable with our current PID. 110 uptr count = internal_snprintf(kAtosMachPortEnvEntry, 111 sizeof(kAtosMachPortEnvEntry), 112 K_ATOS_ENV_VAR "=%s", pid_str_); 113 CHECK_GE(count, sizeof(K_ATOS_ENV_VAR) + internal_strlen(pid_str_)); 114 // Document our assumption but without calling `getenv()` in normal 115 // builds. 116 DCHECK(getenv(K_ATOS_ENV_VAR)); 117 DCHECK_EQ(internal_strcmp(getenv(K_ATOS_ENV_VAR), pid_str_), 0); 118 } 119 120 return SymbolizerProcess::StartSymbolizerSubprocess(); 121 } 122 123 bool ReachedEndOfOutput(const char *buffer, uptr length) const override { 124 return (length >= 1 && buffer[length - 1] == '\n'); 125 } 126 127 void GetArgV(const char *path_to_binary, 128 const char *(&argv)[kArgVMax]) const override { 129 int i = 0; 130 argv[i++] = path_to_binary; 131 argv[i++] = "-p"; 132 argv[i++] = &pid_str_[0]; 133 if (GetMacosAlignedVersion() == MacosVersion(10, 9)) { 134 // On Mavericks atos prints a deprecation warning which we suppress by 135 // passing -d. The warning isn't present on other OSX versions, even the 136 // newer ones. 137 argv[i++] = "-d"; 138 } 139 argv[i++] = nullptr; 140 } 141 142 char pid_str_[16]; 143 // Space for `\0` in `K_ATOS_ENV_VAR` is reused for `=`. 144 static_assert(sizeof(kAtosMachPortEnvEntry) == 145 (sizeof(K_ATOS_ENV_VAR) + sizeof(pid_str_)), 146 "sizes should match"); 147 }; 148 149 #undef K_ATOS_ENV_VAR 150 151 static bool ParseCommandOutput(const char *str, uptr addr, char **out_name, 152 char **out_module, char **out_file, uptr *line, 153 uptr *start_address) { 154 // Trim ending newlines. 155 char *trim; 156 ExtractTokenUpToDelimiter(str, "\n", &trim); 157 158 // The line from `atos` is in one of these formats: 159 // myfunction (in library.dylib) (sourcefile.c:17) 160 // myfunction (in library.dylib) + 0x1fe 161 // myfunction (in library.dylib) + 15 162 // 0xdeadbeef (in library.dylib) + 0x1fe 163 // 0xdeadbeef (in library.dylib) + 15 164 // 0xdeadbeef (in library.dylib) 165 // 0xdeadbeef 166 167 const char *rest = trim; 168 char *symbol_name; 169 rest = ExtractTokenUpToDelimiter(rest, " (in ", &symbol_name); 170 if (rest[0] == '\0') { 171 InternalFree(symbol_name); 172 InternalFree(trim); 173 return false; 174 } 175 176 if (internal_strncmp(symbol_name, "0x", 2) != 0) 177 *out_name = symbol_name; 178 else 179 InternalFree(symbol_name); 180 rest = ExtractTokenUpToDelimiter(rest, ") ", out_module); 181 182 if (rest[0] == '(') { 183 if (out_file) { 184 rest++; 185 rest = ExtractTokenUpToDelimiter(rest, ":", out_file); 186 char *extracted_line_number; 187 rest = ExtractTokenUpToDelimiter(rest, ")", &extracted_line_number); 188 if (line) *line = (uptr)internal_atoll(extracted_line_number); 189 InternalFree(extracted_line_number); 190 } 191 } else if (rest[0] == '+') { 192 rest += 2; 193 uptr offset = internal_atoll(rest); 194 if (start_address) *start_address = addr - offset; 195 } 196 197 InternalFree(trim); 198 return true; 199 } 200 201 AtosSymbolizer::AtosSymbolizer(const char *path, LowLevelAllocator *allocator) 202 : process_(new (*allocator) AtosSymbolizerProcess(path)) {} 203 204 bool AtosSymbolizer::SymbolizePC(uptr addr, SymbolizedStack *stack) { 205 if (!process_) return false; 206 if (addr == 0) return false; 207 char command[32]; 208 internal_snprintf(command, sizeof(command), "0x%zx\n", addr); 209 const char *buf = process_->SendCommand(command); 210 if (!buf) return false; 211 uptr line; 212 uptr start_address = AddressInfo::kUnknown; 213 if (!ParseCommandOutput(buf, addr, &stack->info.function, &stack->info.module, 214 &stack->info.file, &line, &start_address)) { 215 process_ = nullptr; 216 return false; 217 } 218 stack->info.line = (int)line; 219 220 if (start_address == AddressInfo::kUnknown) { 221 // Fallback to dladdr() to get function start address if atos doesn't report 222 // it. 223 Dl_info info; 224 int result = dladdr((const void *)addr, &info); 225 if (result) 226 start_address = reinterpret_cast<uptr>(info.dli_saddr); 227 } 228 229 // Only assign to `function_offset` if we were able to get the function's 230 // start address and we got a sensible `start_address` (dladdr doesn't always 231 // ensure that `addr >= sym_addr`). 232 if (start_address != AddressInfo::kUnknown && addr >= start_address) { 233 stack->info.function_offset = addr - start_address; 234 } 235 return true; 236 } 237 238 bool AtosSymbolizer::SymbolizeData(uptr addr, DataInfo *info) { 239 if (!process_) return false; 240 char command[32]; 241 internal_snprintf(command, sizeof(command), "0x%zx\n", addr); 242 const char *buf = process_->SendCommand(command); 243 if (!buf) return false; 244 if (!ParseCommandOutput(buf, addr, &info->name, &info->module, nullptr, 245 nullptr, &info->start)) { 246 process_ = nullptr; 247 return false; 248 } 249 return true; 250 } 251 252 void AtosSymbolizer::LateInitialize() { process_->LateInitialize(); } 253 254 } // namespace __sanitizer 255 256 #endif // SANITIZER_MAC 257