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_APPLE
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 <stdlib.h>
24#include <sys/wait.h>
25#include <unistd.h>
26#include <util.h>
27
28namespace __sanitizer {
29
30bool DlAddrSymbolizer::SymbolizePC(uptr addr, SymbolizedStack *stack) {
31  Dl_info info;
32  int result = dladdr((const void *)addr, &info);
33  if (!result) return false;
34
35  // Compute offset if possible. `dladdr()` doesn't always ensure that `addr >=
36  // sym_addr` so only compute the offset when this holds. Failure to find the
37  // function offset is not treated as a failure because it might still be
38  // possible to get the symbol name.
39  uptr sym_addr = reinterpret_cast<uptr>(info.dli_saddr);
40  if (addr >= sym_addr) {
41    stack->info.function_offset = addr - sym_addr;
42  }
43
44  const char *demangled = DemangleSwiftAndCXX(info.dli_sname);
45  if (!demangled) return false;
46  stack->info.function = internal_strdup(demangled);
47  return true;
48}
49
50bool DlAddrSymbolizer::SymbolizeData(uptr addr, DataInfo *datainfo) {
51  Dl_info info;
52  int result = dladdr((const void *)addr, &info);
53  if (!result) return false;
54  const char *demangled = DemangleSwiftAndCXX(info.dli_sname);
55  datainfo->name = internal_strdup(demangled);
56  datainfo->start = (uptr)info.dli_saddr;
57  return true;
58}
59
60class AtosSymbolizerProcess final : public SymbolizerProcess {
61 public:
62  explicit AtosSymbolizerProcess(const char *path)
63      : SymbolizerProcess(path, /*use_posix_spawn*/ true) {
64    pid_str_[0] = '\0';
65  }
66
67 private:
68  bool StartSymbolizerSubprocess() override {
69    // Put the string command line argument in the object so that it outlives
70    // the call to GetArgV.
71    internal_snprintf(pid_str_, sizeof(pid_str_), "%d", (int)internal_getpid());
72
73    // Configure sandbox before starting atos process.
74    return SymbolizerProcess::StartSymbolizerSubprocess();
75  }
76
77  bool ReachedEndOfOutput(const char *buffer, uptr length) const override {
78    return (length >= 1 && buffer[length - 1] == '\n');
79  }
80
81  void GetArgV(const char *path_to_binary,
82               const char *(&argv)[kArgVMax]) const override {
83    int i = 0;
84    argv[i++] = path_to_binary;
85    argv[i++] = "-p";
86    argv[i++] = &pid_str_[0];
87    if (GetMacosAlignedVersion() == MacosVersion(10, 9)) {
88      // On Mavericks atos prints a deprecation warning which we suppress by
89      // passing -d. The warning isn't present on other OSX versions, even the
90      // newer ones.
91      argv[i++] = "-d";
92    }
93    argv[i++] = nullptr;
94    CHECK_LE(i, kArgVMax);
95  }
96
97  char pid_str_[16];
98};
99
100#undef K_ATOS_ENV_VAR
101
102static bool ParseCommandOutput(const char *str, uptr addr, char **out_name,
103                               char **out_module, char **out_file, uptr *line,
104                               uptr *start_address) {
105  // Trim ending newlines.
106  char *trim;
107  ExtractTokenUpToDelimiter(str, "\n", &trim);
108
109  // The line from `atos` is in one of these formats:
110  //   myfunction (in library.dylib) (sourcefile.c:17)
111  //   myfunction (in library.dylib) + 0x1fe
112  //   myfunction (in library.dylib) + 15
113  //   0xdeadbeef (in library.dylib) + 0x1fe
114  //   0xdeadbeef (in library.dylib) + 15
115  //   0xdeadbeef (in library.dylib)
116  //   0xdeadbeef
117
118  const char *rest = trim;
119  char *symbol_name;
120  rest = ExtractTokenUpToDelimiter(rest, " (in ", &symbol_name);
121  if (rest[0] == '\0') {
122    InternalFree(symbol_name);
123    InternalFree(trim);
124    return false;
125  }
126
127  if (internal_strncmp(symbol_name, "0x", 2) != 0)
128    *out_name = symbol_name;
129  else
130    InternalFree(symbol_name);
131  rest = ExtractTokenUpToDelimiter(rest, ") ", out_module);
132
133  if (rest[0] == '(') {
134    if (out_file) {
135      rest++;
136      rest = ExtractTokenUpToDelimiter(rest, ":", out_file);
137      char *extracted_line_number;
138      rest = ExtractTokenUpToDelimiter(rest, ")", &extracted_line_number);
139      if (line) *line = (uptr)internal_atoll(extracted_line_number);
140      InternalFree(extracted_line_number);
141    }
142  } else if (rest[0] == '+') {
143    rest += 2;
144    uptr offset = internal_atoll(rest);
145    if (start_address) *start_address = addr - offset;
146  }
147
148  InternalFree(trim);
149  return true;
150}
151
152AtosSymbolizer::AtosSymbolizer(const char *path, LowLevelAllocator *allocator)
153    : process_(new (*allocator) AtosSymbolizerProcess(path)) {}
154
155bool AtosSymbolizer::SymbolizePC(uptr addr, SymbolizedStack *stack) {
156  if (!process_) return false;
157  if (addr == 0) return false;
158  char command[32];
159  internal_snprintf(command, sizeof(command), "0x%zx\n", addr);
160  const char *buf = process_->SendCommand(command);
161  if (!buf) return false;
162  uptr line;
163  uptr start_address = AddressInfo::kUnknown;
164  if (!ParseCommandOutput(buf, addr, &stack->info.function, &stack->info.module,
165                          &stack->info.file, &line, &start_address)) {
166    process_ = nullptr;
167    return false;
168  }
169  stack->info.line = (int)line;
170
171  if (start_address == AddressInfo::kUnknown) {
172    // Fallback to dladdr() to get function start address if atos doesn't report
173    // it.
174    Dl_info info;
175    int result = dladdr((const void *)addr, &info);
176    if (result)
177      start_address = reinterpret_cast<uptr>(info.dli_saddr);
178  }
179
180  // Only assign to `function_offset` if we were able to get the function's
181  // start address and we got a sensible `start_address` (dladdr doesn't always
182  // ensure that `addr >= sym_addr`).
183  if (start_address != AddressInfo::kUnknown && addr >= start_address) {
184    stack->info.function_offset = addr - start_address;
185  }
186  return true;
187}
188
189bool AtosSymbolizer::SymbolizeData(uptr addr, DataInfo *info) {
190  if (!process_) return false;
191  char command[32];
192  internal_snprintf(command, sizeof(command), "0x%zx\n", addr);
193  const char *buf = process_->SendCommand(command);
194  if (!buf) return false;
195  if (!ParseCommandOutput(buf, addr, &info->name, &info->module, nullptr,
196                          nullptr, &info->start)) {
197    process_ = nullptr;
198    return false;
199  }
200  return true;
201}
202
203}  // namespace __sanitizer
204
205#endif  // SANITIZER_APPLE
206