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 <dlfcn.h>
18#  include <errno.h>
19#  include <stdlib.h>
20#  include <sys/wait.h>
21#  include <unistd.h>
22#  include <util.h>
23
24#  include "sanitizer_allocator_internal.h"
25#  include "sanitizer_mac.h"
26#  include "sanitizer_symbolizer_mac.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)
46    demangled = info.dli_sname;
47  stack->info.function = internal_strdup(demangled);
48  return true;
49}
50
51bool 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  if (!demangled)
57    demangled = info.dli_sname;
58  datainfo->name = internal_strdup(demangled);
59  datainfo->start = (uptr)info.dli_saddr;
60  return true;
61}
62
63class AtosSymbolizerProcess final : public SymbolizerProcess {
64 public:
65  explicit AtosSymbolizerProcess(const char *path)
66      : SymbolizerProcess(path, /*use_posix_spawn*/ true) {
67    pid_str_[0] = '\0';
68  }
69
70 private:
71  bool StartSymbolizerSubprocess() override {
72    // Put the string command line argument in the object so that it outlives
73    // the call to GetArgV.
74    internal_snprintf(pid_str_, sizeof(pid_str_), "%d", (int)internal_getpid());
75
76    // Configure sandbox before starting atos process.
77    return SymbolizerProcess::StartSymbolizerSubprocess();
78  }
79
80  bool ReachedEndOfOutput(const char *buffer, uptr length) const override {
81    return (length >= 1 && buffer[length - 1] == '\n');
82  }
83
84  void GetArgV(const char *path_to_binary,
85               const char *(&argv)[kArgVMax]) const override {
86    int i = 0;
87    argv[i++] = path_to_binary;
88    argv[i++] = "-p";
89    argv[i++] = &pid_str_[0];
90    if (GetMacosAlignedVersion() == MacosVersion(10, 9)) {
91      // On Mavericks atos prints a deprecation warning which we suppress by
92      // passing -d. The warning isn't present on other OSX versions, even the
93      // newer ones.
94      argv[i++] = "-d";
95    }
96    argv[i++] = nullptr;
97    CHECK_LE(i, kArgVMax);
98  }
99
100  char pid_str_[16];
101};
102
103#undef K_ATOS_ENV_VAR
104
105static bool ParseCommandOutput(const char *str, uptr addr, char **out_name,
106                               char **out_module, char **out_file, uptr *line,
107                               uptr *start_address) {
108  // Trim ending newlines.
109  char *trim;
110  ExtractTokenUpToDelimiter(str, "\n", &trim);
111
112  // The line from `atos` is in one of these formats:
113  //   myfunction (in library.dylib) (sourcefile.c:17)
114  //   myfunction (in library.dylib) + 0x1fe
115  //   myfunction (in library.dylib) + 15
116  //   0xdeadbeef (in library.dylib) + 0x1fe
117  //   0xdeadbeef (in library.dylib) + 15
118  //   0xdeadbeef (in library.dylib)
119  //   0xdeadbeef
120
121  const char *rest = trim;
122  char *symbol_name;
123  rest = ExtractTokenUpToDelimiter(rest, " (in ", &symbol_name);
124  if (rest[0] == '\0') {
125    InternalFree(symbol_name);
126    InternalFree(trim);
127    return false;
128  }
129
130  if (internal_strncmp(symbol_name, "0x", 2) != 0)
131    *out_name = symbol_name;
132  else
133    InternalFree(symbol_name);
134  rest = ExtractTokenUpToDelimiter(rest, ") ", out_module);
135
136  if (rest[0] == '(') {
137    if (out_file) {
138      rest++;
139      rest = ExtractTokenUpToDelimiter(rest, ":", out_file);
140      char *extracted_line_number;
141      rest = ExtractTokenUpToDelimiter(rest, ")", &extracted_line_number);
142      if (line) *line = (uptr)internal_atoll(extracted_line_number);
143      InternalFree(extracted_line_number);
144    }
145  } else if (rest[0] == '+') {
146    rest += 2;
147    uptr offset = internal_atoll(rest);
148    if (start_address) *start_address = addr - offset;
149  }
150
151  InternalFree(trim);
152  return true;
153}
154
155AtosSymbolizer::AtosSymbolizer(const char *path, LowLevelAllocator *allocator)
156    : process_(new (*allocator) AtosSymbolizerProcess(path)) {}
157
158bool AtosSymbolizer::SymbolizePC(uptr addr, SymbolizedStack *stack) {
159  if (!process_) return false;
160  if (addr == 0) return false;
161  char command[32];
162  internal_snprintf(command, sizeof(command), "0x%zx\n", addr);
163  const char *buf = process_->SendCommand(command);
164  if (!buf) return false;
165  uptr line;
166  uptr start_address = AddressInfo::kUnknown;
167  if (!ParseCommandOutput(buf, addr, &stack->info.function, &stack->info.module,
168                          &stack->info.file, &line, &start_address)) {
169    Report("WARNING: atos failed to symbolize address \"0x%zx\"\n", addr);
170    return false;
171  }
172  stack->info.line = (int)line;
173
174  if (start_address == AddressInfo::kUnknown) {
175    // Fallback to dladdr() to get function start address if atos doesn't report
176    // it.
177    Dl_info info;
178    int result = dladdr((const void *)addr, &info);
179    if (result)
180      start_address = reinterpret_cast<uptr>(info.dli_saddr);
181  }
182
183  // Only assign to `function_offset` if we were able to get the function's
184  // start address and we got a sensible `start_address` (dladdr doesn't always
185  // ensure that `addr >= sym_addr`).
186  if (start_address != AddressInfo::kUnknown && addr >= start_address) {
187    stack->info.function_offset = addr - start_address;
188  }
189  return true;
190}
191
192bool AtosSymbolizer::SymbolizeData(uptr addr, DataInfo *info) {
193  if (!process_) return false;
194  char command[32];
195  internal_snprintf(command, sizeof(command), "0x%zx\n", addr);
196  const char *buf = process_->SendCommand(command);
197  if (!buf) return false;
198  if (!ParseCommandOutput(buf, addr, &info->name, &info->module, nullptr,
199                          nullptr, &info->start)) {
200    process_ = nullptr;
201    return false;
202  }
203  return true;
204}
205
206}  // namespace __sanitizer
207
208#endif  // SANITIZER_APPLE
209