/thirdparty/breakpad/third_party/glog/src/symbolize.h

  1// Copyright (c) 2006, Google Inc.
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  9// notice, this list of conditions and the following disclaimer.
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 17//
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 29//
 30// Author: Satoru Takabayashi
 31//
 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.).
 36//
 37// The algorithm used in Symbolize() is as follows.
 38//
 39//   1. Go through a list of maps in /proc/self/maps and find the map
 40//   containing the program counter.
 41//
 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.
 48//
 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.
 53
 54#ifndef BASE_SYMBOLIZE_H_
 55#define BASE_SYMBOLIZE_H_
 56
 57#include "utilities.h"
 58#include "config.h"
 59#include "glog/logging.h"
 60
 61#ifdef HAVE_SYMBOLIZE
 62
 63#if defined(__ELF__)  // defined by gcc on Linux
 64#include <elf.h>
 65#include <link.h>  // For ElfW() macro.
 66
 67// If there is no ElfW macro, let's define it by ourself.
 68#ifndef ElfW
 69# if SIZEOF_VOID_P == 4
 70#  define ElfW(type) Elf32_##type
 71# elif SIZEOF_VOID_P == 8
 72#  define ElfW(type) Elf64_##type
 73# else
 74#  error "Unknown sizeof(void *)"
 75# endif
 76#endif
 77
 78_START_GOOGLE_NAMESPACE_
 79
 80// Gets the section header for the given name, if it exists. Returns true on
 81// success. Otherwise, returns false.
 82bool GetSectionHeaderByName(int fd, const char *name, size_t name_len,
 83                            ElfW(Shdr) *out);
 84
 85_END_GOOGLE_NAMESPACE_
 86
 87#endif  /* __ELF__ */
 88
 89_START_GOOGLE_NAMESPACE_
 90
 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.
 98typedef int (*SymbolizeCallback)(int fd, void *pc, char *out, size_t out_size,
 99                                 uint64 relocation);
100void InstallSymbolizeCallback(SymbolizeCallback callback);
101
102_END_GOOGLE_NAMESPACE_
103
104#endif
105
106_START_GOOGLE_NAMESPACE_
107
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,
111// returns false.
112bool Symbolize(void *pc, char *out, int out_size);
113
114_END_GOOGLE_NAMESPACE_
115
116#endif  // BASE_SYMBOLIZE_H_