1 //===-- sanitizer_symbolizer_internal.h -------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Header for internal classes and functions to be used by implementations of
11 // symbolizers.
12 //
13 //===----------------------------------------------------------------------===//
14 #ifndef SANITIZER_SYMBOLIZER_INTERNAL_H
15 #define SANITIZER_SYMBOLIZER_INTERNAL_H
16 
17 #include "sanitizer_symbolizer.h"
18 
19 namespace __sanitizer {
20 
21 // Parsing helpers, 'str' is searched for delimiter(s) and a string or uptr
22 // is extracted. When extracting a string, a newly allocated (using
23 // InternalAlloc) and null-terminataed buffer is returned. They return a pointer
24 // to the next characted after the found delimiter.
25 const char *ExtractToken(const char *str, const char *delims, char **result);
26 const char *ExtractInt(const char *str, const char *delims, int *result);
27 const char *ExtractUptr(const char *str, const char *delims, uptr *result);
28 const char *ExtractTokenUpToDelimiter(const char *str, const char *delimiter,
29                                       char **result);
30 
31 const char *DemangleCXXABI(const char *name);
32 
33 // SymbolizerTool is an interface that is implemented by individual "tools"
34 // that can perform symbolication (external llvm-symbolizer, libbacktrace,
35 // Windows DbgHelp symbolizer, etc.).
36 class SymbolizerTool {
37  public:
38   // The main |Symbolizer| class implements a "fallback chain" of symbolizer
39   // tools. In a request to symbolize an address, if one tool returns false,
40   // the next tool in the chain will be tried.
41   SymbolizerTool *next;
42 
SymbolizerTool()43   SymbolizerTool() : next(nullptr) { }
44 
45   // Can't declare pure virtual functions in sanitizer runtimes:
46   // __cxa_pure_virtual might be unavailable.
47 
48   // The |stack| parameter is inout. It is pre-filled with the address,
49   // module base and module offset values and is to be used to construct
50   // other stack frames.
SymbolizePC(uptr addr,SymbolizedStack * stack)51   virtual bool SymbolizePC(uptr addr, SymbolizedStack *stack) {
52     UNIMPLEMENTED();
53   }
54 
55   // The |info| parameter is inout. It is pre-filled with the module base
56   // and module offset values.
SymbolizeData(uptr addr,DataInfo * info)57   virtual bool SymbolizeData(uptr addr, DataInfo *info) {
58     UNIMPLEMENTED();
59   }
60 
Flush()61   virtual void Flush() {}
62 
63   // Return nullptr to fallback to the default platform-specific demangler.
Demangle(const char * name)64   virtual const char *Demangle(const char *name) {
65     return nullptr;
66   }
67 };
68 
69 // SymbolizerProcess encapsulates communication between the tool and
70 // external symbolizer program, running in a different subprocess.
71 // SymbolizerProcess may not be used from two threads simultaneously.
72 class SymbolizerProcess {
73  public:
74   explicit SymbolizerProcess(const char *path, bool use_forkpty = false);
75   const char *SendCommand(const char *command);
76 
77  protected:
ReachedEndOfOutput(const char * buffer,uptr length)78   virtual bool ReachedEndOfOutput(const char *buffer, uptr length) const {
79     UNIMPLEMENTED();
80   }
81 
82   /// The maximum number of arguments required to invoke a tool process.
83   enum { kArgVMax = 6 };
84 
85   /// Fill in an argv array to invoke the child process.
GetArgV(const char * path_to_binary,const char * (& argv)[kArgVMax])86   virtual void GetArgV(const char *path_to_binary,
87                        const char *(&argv)[kArgVMax]) const {
88     UNIMPLEMENTED();
89   }
90 
91   virtual bool ReadFromSymbolizer(char *buffer, uptr max_length);
92 
93  private:
94   bool Restart();
95   const char *SendCommandImpl(const char *command);
96   bool WriteToSymbolizer(const char *buffer, uptr length);
97   bool StartSymbolizerSubprocess();
98 
99   const char *path_;
100   fd_t input_fd_;
101   fd_t output_fd_;
102 
103   static const uptr kBufferSize = 16 * 1024;
104   char buffer_[kBufferSize];
105 
106   static const uptr kMaxTimesRestarted = 5;
107   static const int kSymbolizerStartupTimeMillis = 10;
108   uptr times_restarted_;
109   bool failed_to_start_;
110   bool reported_invalid_path_;
111   bool use_forkpty_;
112 };
113 
114 class LLVMSymbolizerProcess;
115 
116 // This tool invokes llvm-symbolizer in a subprocess. It should be as portable
117 // as the llvm-symbolizer tool is.
118 class LLVMSymbolizer : public SymbolizerTool {
119  public:
120   explicit LLVMSymbolizer(const char *path, LowLevelAllocator *allocator);
121 
122   bool SymbolizePC(uptr addr, SymbolizedStack *stack) override;
123 
124   bool SymbolizeData(uptr addr, DataInfo *info) override;
125 
126  private:
127   const char *SendCommand(bool is_data, const char *module_name,
128                           uptr module_offset);
129 
130   LLVMSymbolizerProcess *symbolizer_process_;
131   static const uptr kBufferSize = 16 * 1024;
132   char buffer_[kBufferSize];
133 };
134 
135 // Parses one or more two-line strings in the following format:
136 //   <function_name>
137 //   <file_name>:<line_number>[:<column_number>]
138 // Used by LLVMSymbolizer, Addr2LinePool and InternalSymbolizer, since all of
139 // them use the same output format.  Returns true if any useful debug
140 // information was found.
141 void ParseSymbolizePCOutput(const char *str, SymbolizedStack *res);
142 
143 // Parses a two-line string in the following format:
144 //   <symbol_name>
145 //   <start_address> <size>
146 // Used by LLVMSymbolizer and InternalSymbolizer.
147 void ParseSymbolizeDataOutput(const char *str, DataInfo *info);
148 
149 }  // namespace __sanitizer
150 
151 #endif  // SANITIZER_SYMBOLIZER_INTERNAL_H
152