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_symbolizer.h"
17 #include "sanitizer_file.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-terminataed 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 
74 // SymbolizerProcess encapsulates communication between the tool and
75 // external symbolizer program, running in a different subprocess.
76 // SymbolizerProcess may not be used from two threads simultaneously.
77 class SymbolizerProcess {
78  public:
79   explicit SymbolizerProcess(const char *path, bool use_posix_spawn = false);
80   const char *SendCommand(const char *command);
81 
82  protected:
83   /// The maximum number of arguments required to invoke a tool process.
84   static const unsigned kArgVMax = 6;
85 
86   // Customizable by subclasses.
87   virtual bool StartSymbolizerSubprocess();
88   virtual bool ReadFromSymbolizer(char *buffer, uptr max_length);
89 
90  private:
91   virtual bool ReachedEndOfOutput(const char *buffer, uptr length) const {
92     UNIMPLEMENTED();
93   }
94 
95   /// Fill in an argv array to invoke the child process.
96   virtual void GetArgV(const char *path_to_binary,
97                        const char *(&argv)[kArgVMax]) const {
98     UNIMPLEMENTED();
99   }
100 
101   bool Restart();
102   const char *SendCommandImpl(const char *command);
103   bool WriteToSymbolizer(const char *buffer, uptr length);
104 
105   const char *path_;
106   fd_t input_fd_;
107   fd_t output_fd_;
108 
109   static const uptr kBufferSize = 16 * 1024;
110   char buffer_[kBufferSize];
111 
112   static const uptr kMaxTimesRestarted = 5;
113   static const int kSymbolizerStartupTimeMillis = 10;
114   uptr times_restarted_;
115   bool failed_to_start_;
116   bool reported_invalid_path_;
117   bool use_posix_spawn_;
118 };
119 
120 class LLVMSymbolizerProcess;
121 
122 // This tool invokes llvm-symbolizer in a subprocess. It should be as portable
123 // as the llvm-symbolizer tool is.
124 class LLVMSymbolizer : public SymbolizerTool {
125  public:
126   explicit LLVMSymbolizer(const char *path, LowLevelAllocator *allocator);
127 
128   bool SymbolizePC(uptr addr, SymbolizedStack *stack) override;
129   bool SymbolizeData(uptr addr, DataInfo *info) override;
130   bool SymbolizeFrame(uptr addr, FrameInfo *info) override;
131 
132  private:
133   const char *FormatAndSendCommand(const char *command_prefix,
134                                    const char *module_name, uptr module_offset,
135                                    ModuleArch arch);
136 
137   LLVMSymbolizerProcess *symbolizer_process_;
138   static const uptr kBufferSize = 16 * 1024;
139   char buffer_[kBufferSize];
140 };
141 
142 // Parses one or more two-line strings in the following format:
143 //   <function_name>
144 //   <file_name>:<line_number>[:<column_number>]
145 // Used by LLVMSymbolizer, Addr2LinePool and InternalSymbolizer, since all of
146 // them use the same output format.  Returns true if any useful debug
147 // information was found.
148 void ParseSymbolizePCOutput(const char *str, SymbolizedStack *res);
149 
150 // Parses a two-line string in the following format:
151 //   <symbol_name>
152 //   <start_address> <size>
153 // Used by LLVMSymbolizer and InternalSymbolizer.
154 void ParseSymbolizeDataOutput(const char *str, DataInfo *info);
155 
156 }  // namespace __sanitizer
157 
158 #endif  // SANITIZER_SYMBOLIZER_INTERNAL_H
159