tools/profiler/LulElfInt.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3
   4 // Copyright (c) 2006, 2012, Google Inc.
   5 // All rights reserved.
   6 //
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   8 // modification, are permitted provided that the following conditions are
   9 // met:
  10 //
  11 //     * Redistributions of source code must retain the above copyright
  12 // notice, this list of conditions and the following disclaimer.
  13 //     * Redistributions in binary form must reproduce the above
  14 // copyright notice, this list of conditions and the following disclaimer
  15 // in the documentation and/or other materials provided with the
  16 // distribution.
  17 //     * Neither the name of Google Inc. nor the names of its
  18 // contributors may be used to endorse or promote products derived from
  19 // this software without specific prior written permission.
  20 //
  21 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  24 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  25 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  31 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32
  33 // This file is derived from the following files in
  34 // toolkit/crashreporter/google-breakpad:
  35 //   src/common/android/include/elf.h
  36 //   src/common/linux/elfutils.h
  37 //   src/common/linux/file_id.h
  38 //   src/common/linux/elfutils-inl.h
  39
  40 #ifndef LulElfInt_h
  41 #define LulElfInt_h
  42
  43 // This header defines functions etc internal to the ELF reader.  It
  44 // should not be included outside of LulElf.cpp.
  45
  46 #include <elf.h>
  47 #include <stdlib.h>
  48
  49 #include "mozilla/Assertions.h"
  50
  51 #include "LulPlatformMacros.h"
  52
  53
  54 // (derived from)
  55 // elfutils.h: Utilities for dealing with ELF files.
  56 //
  57
  58 #if defined(LUL_OS_android)
  59
  60 // From toolkit/crashreporter/google-breakpad/src/common/android/include/elf.h
  61 // The Android headers don't always define this constant.
  62 #ifndef EM_X86_64
  63 #define EM_X86_64  62
  64 #endif
  65
  66 #ifndef EM_PPC64
  67 #define EM_PPC64   21
  68 #endif
  69
  70 #ifndef EM_S390
  71 #define EM_S390    22
  72 #endif
  73
  74 #ifndef NT_GNU_BUILD_ID
  75 #define NT_GNU_BUILD_ID 3
  76 #endif
  77
  78 #define ElfW(type)      _ElfW (Elf, ELFSIZE, type)
  79 #define _ElfW(e,w,t)    _ElfW_1 (e, w, _##t)
  80 #define _ElfW_1(e,w,t)  e##w##t
  81
  82 //FIXME
  83 extern "C" {
  84   extern char*  basename(const char*  path);
  85 };
  86 #else
  87
  88 # include <link.h>
  89 #endif
  90
  91
  92 namespace lul {
  93
  94 // Traits classes so consumers can write templatized code to deal
  95 // with specific ELF bits.
  96 struct ElfClass32 {
  97   typedef Elf32_Addr Addr;
  98   typedef Elf32_Ehdr Ehdr;
  99   typedef Elf32_Nhdr Nhdr;
 100   typedef Elf32_Phdr Phdr;
 101   typedef Elf32_Shdr Shdr;
 102   typedef Elf32_Half Half;
 103   typedef Elf32_Off Off;
 104   typedef Elf32_Word Word;
 105   static const int kClass = ELFCLASS32;
 106   static const size_t kAddrSize = sizeof(Elf32_Addr);
 107 };
 108
 109 struct ElfClass64 {
 110   typedef Elf64_Addr Addr;
 111   typedef Elf64_Ehdr Ehdr;
 112   typedef Elf64_Nhdr Nhdr;
 113   typedef Elf64_Phdr Phdr;
 114   typedef Elf64_Shdr Shdr;
 115   typedef Elf64_Half Half;
 116   typedef Elf64_Off Off;
 117   typedef Elf64_Word Word;
 118   static const int kClass = ELFCLASS64;
 119   static const size_t kAddrSize = sizeof(Elf64_Addr);
 120 };
 121
 122 bool IsValidElf(const void* elf_header);
 123 int ElfClass(const void* elf_base);
 124
 125 // Attempt to find a section named |section_name| of type |section_type|
 126 // in the ELF binary data at |elf_mapped_base|. On success, returns true
 127 // and sets |*section_start| to point to the start of the section data,
 128 // and |*section_size| to the size of the section's data. If |elfclass|
 129 // is not NULL, set |*elfclass| to the ELF file class.
 130 bool FindElfSection(const void *elf_mapped_base,
 131                     const char *section_name,
 132                     uint32_t section_type,
 133                     const void **section_start,
 134                     int *section_size,
 135                     int *elfclass);
 136
 137 // Internal helper method, exposed for convenience for callers
 138 // that already have more info.
 139 template<typename ElfClass>
 140 const typename ElfClass::Shdr*
 141 FindElfSectionByName(const char* name,
 142                      typename ElfClass::Word section_type,
 143                      const typename ElfClass::Shdr* sections,
 144                      const char* section_names,
 145                      const char* names_end,
 146                      int nsection);
 147
 148 // Attempt to find the first segment of type |segment_type| in the ELF
 149 // binary data at |elf_mapped_base|. On success, returns true and sets
 150 // |*segment_start| to point to the start of the segment data, and
 151 // and |*segment_size| to the size of the segment's data. If |elfclass|
 152 // is not NULL, set |*elfclass| to the ELF file class.
 153 bool FindElfSegment(const void *elf_mapped_base,
 154                     uint32_t segment_type,
 155                     const void **segment_start,
 156                     int *segment_size,
 157                     int *elfclass);
 158
 159 // Convert an offset from an Elf header into a pointer to the mapped
 160 // address in the current process. Takes an extra template parameter
 161 // to specify the return type to avoid having to dynamic_cast the
 162 // result.
 163 template<typename ElfClass, typename T>
 164 const T*
 165 GetOffset(const typename ElfClass::Ehdr* elf_header,
 166           typename ElfClass::Off offset);
 167
 168
 169 // (derived from)
 170 // file_id.h: Return a unique identifier for a file
 171 //
 172
 173 static const size_t kMDGUIDSize = sizeof(MDGUID);
 174
 175 class FileID {
 176  public:
 177
 178   // Load the identifier for the elf file mapped into memory at |base| into
 179   // |identifier|.  Return false if the identifier could not be created for the
 180   // file.
 181   static bool ElfFileIdentifierFromMappedFile(const void* base,
 182                                               uint8_t identifier[kMDGUIDSize]);
 183
 184   // Convert the |identifier| data to a NULL terminated string.  The string will
 185   // be formatted as a UUID (e.g., 22F065BB-FC9C-49F7-80FE-26A7CEBD7BCE).
 186   // The |buffer| should be at least 37 bytes long to receive all of the data
 187   // and termination.  Shorter buffers will contain truncated data.
 188   static void ConvertIdentifierToString(const uint8_t identifier[kMDGUIDSize],
 189                                         char* buffer, int buffer_length);
 190 };
 191
 192
 193
 194 template<typename ElfClass, typename T>
 195 const T* GetOffset(const typename ElfClass::Ehdr* elf_header,
 196                    typename ElfClass::Off offset) {
 197   return reinterpret_cast<const T*>(reinterpret_cast<uintptr_t>(elf_header) +
 198                                     offset);
 199 }
 200
 201 template<typename ElfClass>
 202 const typename ElfClass::Shdr* FindElfSectionByName(
 203     const char* name,
 204     typename ElfClass::Word section_type,
 205     const typename ElfClass::Shdr* sections,
 206     const char* section_names,
 207     const char* names_end,
 208     int nsection) {
 209   MOZ_ASSERT(name != NULL);
 210   MOZ_ASSERT(sections != NULL);
 211   MOZ_ASSERT(nsection > 0);
 212
 213   int name_len = strlen(name);
 214   if (name_len == 0)
 215     return NULL;
 216
 217   for (int i = 0; i < nsection; ++i) {
 218     const char* section_name = section_names + sections[i].sh_name;
 219     if (sections[i].sh_type == section_type &&
 220         names_end - section_name >= name_len + 1 &&
 221         strcmp(name, section_name) == 0) {
 222       return sections + i;
 223     }
 224   }
 225   return NULL;
 226 }
 227
 228 } // namespace lul
 229
 230
 231 // And finally, the external interface, offered to LulMain.cpp
 232 #include "LulElfExt.h"
 233
 234 #endif // LulElfInt_h