base/third_party/symbolize/symbolize.h

   1 // Copyright (c) 2006, Google Inc.
   2 // All rights reserved.
   3 //
   4 // Redistribution and use in source and binary forms, with or without
   5 // modification, are permitted provided that the following conditions are
   6 // met:
   7 //
   8 //     * Redistributions of source code must retain the above copyright
   9 // notice, this list of conditions and the following disclaimer.
  10 //     * Redistributions in binary form must reproduce the above
  11 // copyright notice, this list of conditions and the following disclaimer
  12 // in the documentation and/or other materials provided with the
  13 // distribution.
  14 //     * Neither the name of Google Inc. nor the names of its
  15 // contributors may be used to endorse or promote products derived from
  16 // this software without specific prior written permission.
  17 //
  18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  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
  64 #if defined(__OpenBSD__)
  65 #include <sys/exec_elf.h>
  66 #else
  67 #include <elf.h>
  68 #endif
  69
  70 #if !defined(ANDROID)
  71 #include <link.h>  // For ElfW() macro.
  72 #endif
  73
  74 // For systems where SIZEOF_VOID_P is not defined, determine it
  75 // based on __LP64__ (defined by gcc on 64-bit systems)
  76 #if !defined(SIZEOF_VOID_P)
  77 # if defined(__LP64__)
  78 #  define SIZEOF_VOID_P 8
  79 # else
  80 #  define SIZEOF_VOID_P 4
  81 # endif
  82 #endif
  83
  84 // If there is no ElfW macro, let's define it by ourself.
  85 #ifndef ElfW
  86 # if SIZEOF_VOID_P == 4
  87 #  define ElfW(type) Elf32_##type
  88 # elif SIZEOF_VOID_P == 8
  89 #  define ElfW(type) Elf64_##type
  90 # else
  91 #  error "Unknown sizeof(void *)"
  92 # endif
  93 #endif
  94
  95 _START_GOOGLE_NAMESPACE_
  96
  97 // Gets the section header for the given name, if it exists. Returns true on
  98 // success. Otherwise, returns false.
  99 bool GetSectionHeaderByName(int fd, const char *name, size_t name_len,
 100                             ElfW(Shdr) *out);
 101
 102 _END_GOOGLE_NAMESPACE_
 103
 104 #endif  /* __ELF__ */
 105
 106 _START_GOOGLE_NAMESPACE_
 107
 108 // Restrictions on the callbacks that follow:
 109 //  - The callbacks must not use heaps but only use stacks.
 110 //  - The callbacks must be async-signal-safe.
 111
 112 // Installs a callback function, which will be called right before a symbol name
 113 // is printed. The callback is intended to be used for showing a file name and a
 114 // line number preceding a symbol name.
 115 // "fd" is a file descriptor of the object file containing the program
 116 // counter "pc". The callback function should write output to "out"
 117 // and return the size of the output written. On error, the callback
 118 // function should return -1.
 119 typedef int (*SymbolizeCallback)(int fd, void *pc, char *out, size_t out_size,
 120                                  uint64 relocation);
 121 void InstallSymbolizeCallback(SymbolizeCallback callback);
 122
 123 // Installs a callback function, which will be called instead of
 124 // OpenObjectFileContainingPcAndGetStartAddress.  The callback is expected
 125 // to searches for the object file (from /proc/self/maps) that contains
 126 // the specified pc.  If found, sets |start_address| to the start address
 127 // of where this object file is mapped in memory, sets the module base
 128 // address into |base_address|, copies the object file name into
 129 // |out_file_name|, and attempts to open the object file.  If the object
 130 // file is opened successfully, returns the file descriptor.  Otherwise,
 131 // returns -1.  |out_file_name_size| is the size of the file name buffer
 132 // (including the null-terminator).
 133 typedef int (*SymbolizeOpenObjectFileCallback)(uint64_t pc,
 134                                                uint64_t &start_address,
 135                                                uint64_t &base_address,
 136                                                char *out_file_name,
 137                                                int out_file_name_size);
 138 void InstallSymbolizeOpenObjectFileCallback(
 139     SymbolizeOpenObjectFileCallback callback);
 140
 141 _END_GOOGLE_NAMESPACE_
 142
 143 #endif
 144
 145 _START_GOOGLE_NAMESPACE_
 146
 147 // Symbolizes a program counter.  On success, returns true and write the
 148 // symbol name to "out".  The symbol name is demangled if possible
 149 // (supports symbols generated by GCC 3.x or newer).  Otherwise,
 150 // returns false.
 151 bool Symbolize(void *pc, char *out, int out_size);
 152
 153 _END_GOOGLE_NAMESPACE_
 154
 155 #endif  // BASE_SYMBOLIZE_H_