1 // Copyright (c) 2006, Google Inc.
2 // All rights reserved.
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5 // modification, are permitted provided that the following conditions are
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16 // this software without specific prior written permission.
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30 // Author: Satoru Takabayashi
32 // This library provides Symbolize() function that symbolizes program
33 // counters to their corresponding symbol names on linux platforms.
34 // This library has a minimal implementation of an ELF symbol table
35 // reader (i.e. it doesn't depend on libelf, etc.).
37 // The algorithm used in Symbolize() is as follows.
39 // 1. Go through a list of maps in /proc/self/maps and find the map
40 // containing the program counter.
42 // 2. Open the mapped file and find a regular symbol table inside.
43 // Iterate over symbols in the symbol table and look for the symbol
44 // containing the program counter. If such a symbol is found,
45 // obtain the symbol name, and demangle the symbol if possible.
46 // If the symbol isn't found in the regular symbol table (binary is
47 // stripped), try the same thing with a dynamic symbol table.
49 // Note that Symbolize() is originally implemented to be used in
50 // FailureSignalHandler() in base/google.cc. Hence it doesn't use
51 // malloc() and other unsafe operations. It should be both
52 // thread-safe and async-signal-safe.
54 #ifndef BASE_SYMBOLIZE_H_
55 #define BASE_SYMBOLIZE_H_
57 #include "utilities.h"
59 #include "glog/logging.h"
63 #if defined(__ELF__) // defined by gcc on Linux
65 #include <link.h> // For ElfW() macro.
67 // If there is no ElfW macro, let's define it by ourself.
69 # if SIZEOF_VOID_P == 4
70 # define ElfW(type) Elf32_##type
71 # elif SIZEOF_VOID_P == 8
72 # define ElfW(type) Elf64_##type
74 # error "Unknown sizeof(void *)"
78 _START_GOOGLE_NAMESPACE_
80 // Gets the section header for the given name, if it exists. Returns true on
81 // success. Otherwise, returns false.
82 bool GetSectionHeaderByName(int fd, const char *name, size_t name_len,
85 _END_GOOGLE_NAMESPACE_
89 _START_GOOGLE_NAMESPACE_
91 // Installs a callback function, which will be called right before a symbol name
92 // is printed. The callback is intended to be used for showing a file name and a
93 // line number preceding a symbol name.
94 // "fd" is a file descriptor of the object file containing the program
95 // counter "pc". The callback function should write output to "out"
96 // and return the size of the output written. On error, the callback
97 // function should return -1.
98 typedef int (*SymbolizeCallback)(int fd, void *pc, char *out, size_t out_size,
100 void InstallSymbolizeCallback(SymbolizeCallback callback);
102 _END_GOOGLE_NAMESPACE_
106 _START_GOOGLE_NAMESPACE_
108 // Symbolizes a program counter. On success, returns true and write the
109 // symbol name to "out". The symbol name is demangled if possible
110 // (supports symbols generated by GCC 3.x or newer). Otherwise,
112 bool Symbolize(void *pc, char *out, int out_size);
114 _END_GOOGLE_NAMESPACE_
116 #endif // BASE_SYMBOLIZE_H_