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