1 //===-- sanitizer_symbolizer_internal.h -------------------------*- C++ -*-===//
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 // Header for internal classes and functions to be used by implementations of
10 // symbolizers.
11 //
12 //===----------------------------------------------------------------------===//
13 #ifndef SANITIZER_SYMBOLIZER_INTERNAL_H
14 #define SANITIZER_SYMBOLIZER_INTERNAL_H
15 
16 #include "sanitizer_file.h"
17 #include "sanitizer_symbolizer.h"
18 #include "sanitizer_vector.h"
19 
20 namespace __sanitizer {
21 
22 // Parsing helpers, 'str' is searched for delimiter(s) and a string or uptr
23 // is extracted. When extracting a string, a newly allocated (using
24 // InternalAlloc) and null-terminated buffer is returned. They return a pointer
25 // to the next characted after the found delimiter.
26 const char *ExtractToken(const char *str, const char *delims, char **result);
27 const char *ExtractInt(const char *str, const char *delims, int *result);
28 const char *ExtractUptr(const char *str, const char *delims, uptr *result);
29 const char *ExtractTokenUpToDelimiter(const char *str, const char *delimiter,
30                                       char **result);
31 
32 const char *DemangleSwiftAndCXX(const char *name);
33 
34 // SymbolizerTool is an interface that is implemented by individual "tools"
35 // that can perform symbolication (external llvm-symbolizer, libbacktrace,
36 // Windows DbgHelp symbolizer, etc.).
37 class SymbolizerTool {
38  public:
39   // The main |Symbolizer| class implements a "fallback chain" of symbolizer
40   // tools. In a request to symbolize an address, if one tool returns false,
41   // the next tool in the chain will be tried.
42   SymbolizerTool *next;
43 
44   SymbolizerTool() : next(nullptr) { }
45 
46   // Can't declare pure virtual functions in sanitizer runtimes:
47   // __cxa_pure_virtual might be unavailable.
48 
49   // The |stack| parameter is inout. It is pre-filled with the address,
50   // module base and module offset values and is to be used to construct
51   // other stack frames.
52   virtual bool SymbolizePC(uptr addr, SymbolizedStack *stack) {
53     UNIMPLEMENTED();
54   }
55 
56   // The |info| parameter is inout. It is pre-filled with the module base
57   // and module offset values.
58   virtual bool SymbolizeData(uptr addr, DataInfo *info) {
59     UNIMPLEMENTED();
60   }
61 
62   virtual bool SymbolizeFrame(uptr addr, FrameInfo *info) {
63     return false;
64   }
65 
66   virtual void Flush() {}
67 
68   // Return nullptr to fallback to the default platform-specific demangler.
69   virtual const char *Demangle(const char *name) {
70     return nullptr;
71   }
72 
73  protected:
74   ~SymbolizerTool() {}
75 };
76 
77 // SymbolizerProcess encapsulates communication between the tool and
78 // external symbolizer program, running in a different subprocess.
79 // SymbolizerProcess may not be used from two threads simultaneously.
80 class SymbolizerProcess {
81  public:
82   explicit SymbolizerProcess(const char *path, bool use_posix_spawn = false);
83   const char *SendCommand(const char *command);
84 
85  protected:
86   ~SymbolizerProcess() {}
87 
88   /// The maximum number of arguments required to invoke a tool process.
89   static const unsigned kArgVMax = 16;
90 
91   // Customizable by subclasses.
92   virtual bool StartSymbolizerSubprocess();
93   virtual bool ReadFromSymbolizer();
94   // Return the environment to run the symbolizer in.
95   virtual char **GetEnvP() { return GetEnviron(); }
96   InternalMmapVector<char> &GetBuff() { return buffer_; }
97 
98  private:
99   virtual bool ReachedEndOfOutput(const char *buffer, uptr length) const {
100     UNIMPLEMENTED();
101   }
102 
103   /// Fill in an argv array to invoke the child process.
104   virtual void GetArgV(const char *path_to_binary,
105                        const char *(&argv)[kArgVMax]) const {
106     UNIMPLEMENTED();
107   }
108 
109   bool Restart();
110   const char *SendCommandImpl(const char *command);
111   bool WriteToSymbolizer(const char *buffer, uptr length);
112 
113   const char *path_;
114   fd_t input_fd_;
115   fd_t output_fd_;
116 
117   InternalMmapVector<char> buffer_;
118 
119   static const uptr kMaxTimesRestarted = 5;
120   static const int kSymbolizerStartupTimeMillis = 10;
121   uptr times_restarted_;
122   bool failed_to_start_;
123   bool reported_invalid_path_;
124   bool use_posix_spawn_;
125 };
126 
127 class LLVMSymbolizerProcess;
128 
129 // This tool invokes llvm-symbolizer in a subprocess. It should be as portable
130 // as the llvm-symbolizer tool is.
131 class LLVMSymbolizer final : public SymbolizerTool {
132  public:
133   explicit LLVMSymbolizer(const char *path, LowLevelAllocator *allocator);
134 
135   bool SymbolizePC(uptr addr, SymbolizedStack *stack) override;
136   bool SymbolizeData(uptr addr, DataInfo *info) override;
137   bool SymbolizeFrame(uptr addr, FrameInfo *info) override;
138 
139  private:
140   const char *FormatAndSendCommand(const char *command_prefix,
141                                    const char *module_name, uptr module_offset,
142                                    ModuleArch arch);
143 
144   LLVMSymbolizerProcess *symbolizer_process_;
145   static const uptr kBufferSize = 16 * 1024;
146   char buffer_[kBufferSize];
147 };
148 
149 // Parses one or more two-line strings in the following format:
150 //   <function_name>
151 //   <file_name>:<line_number>[:<column_number>]
152 // Used by LLVMSymbolizer, Addr2LinePool and InternalSymbolizer, since all of
153 // them use the same output format.  Returns true if any useful debug
154 // information was found.
155 void ParseSymbolizePCOutput(const char *str, SymbolizedStack *res);
156 
157 // Parses a two-line string in the following format:
158 //   <symbol_name>
159 //   <start_address> <size>
160 // Used by LLVMSymbolizer and InternalSymbolizer.
161 void ParseSymbolizeDataOutput(const char *str, DataInfo *info);
162 
163 }  // namespace __sanitizer
164 
165 #endif  // SANITIZER_SYMBOLIZER_INTERNAL_H
166