mozglue/baseprofiler/lul/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 //
   7 // Redistribution and use in source and binary forms, with or without
   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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  27 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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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 "PlatformMacros.h"
  52
  53 // (derived from)
  54 // elfutils.h: Utilities for dealing with ELF files.
  55 //
  56 #include <link.h>
  57
  58 #if defined(GP_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 #  ifndef ElfW
  79 #    define ElfW(type) _ElfW(Elf, ELFSIZE, type)
  80 #    define _ElfW(e, w, t) _ElfW_1(e, w, _##t)
  81 #    define _ElfW_1(e, w, t) e##w##t
  82 #  endif
  83
  84 #endif
  85
  86 #if defined(GP_OS_freebsd)
  87
  88 #  ifndef ElfW
  89 #    define ElfW(type) Elf_##type
  90 #  endif
  91
  92 #endif
  93
  94 namespace lul {
  95
  96 // Traits classes so consumers can write templatized code to deal
  97 // with specific ELF bits.
  98 struct ElfClass32 {
  99   typedef Elf32_Addr Addr;
 100   typedef Elf32_Ehdr Ehdr;
 101   typedef Elf32_Nhdr Nhdr;
 102   typedef Elf32_Phdr Phdr;
 103   typedef Elf32_Shdr Shdr;
 104   typedef Elf32_Half Half;
 105   typedef Elf32_Off Off;
 106   typedef Elf32_Word Word;
 107   static const int kClass = ELFCLASS32;
 108   static const size_t kAddrSize = sizeof(Elf32_Addr);
 109 };
 110
 111 struct ElfClass64 {
 112   typedef Elf64_Addr Addr;
 113   typedef Elf64_Ehdr Ehdr;
 114   typedef Elf64_Nhdr Nhdr;
 115   typedef Elf64_Phdr Phdr;
 116   typedef Elf64_Shdr Shdr;
 117   typedef Elf64_Half Half;
 118   typedef Elf64_Off Off;
 119   typedef Elf64_Word Word;
 120   static const int kClass = ELFCLASS64;
 121   static const size_t kAddrSize = sizeof(Elf64_Addr);
 122 };
 123
 124 bool IsValidElf(const void* elf_header);
 125 int ElfClass(const void* elf_base);
 126
 127 // Attempt to find a section named |section_name| of type |section_type|
 128 // in the ELF binary data at |elf_mapped_base|. On success, returns true
 129 // and sets |*section_start| to point to the start of the section data,
 130 // and |*section_size| to the size of the section's data. If |elfclass|
 131 // is not NULL, set |*elfclass| to the ELF file class.
 132 bool FindElfSection(const void* elf_mapped_base, const char* section_name,
 133                     uint32_t section_type, const void** section_start,
 134                     int* section_size, int* elfclass);
 135
 136 // Internal helper method, exposed for convenience for callers
 137 // that already have more info.
 138 template <typename ElfClass>
 139 const typename ElfClass::Shdr* FindElfSectionByName(
 140     const char* name, typename ElfClass::Word section_type,
 141     const typename ElfClass::Shdr* sections, const char* section_names,
 142     const char* names_end, int nsection);
 143
 144 // Attempt to find the first segment of type |segment_type| in the ELF
 145 // binary data at |elf_mapped_base|. On success, returns true and sets
 146 // |*segment_start| to point to the start of the segment data, and
 147 // and |*segment_size| to the size of the segment's data. If |elfclass|
 148 // is not NULL, set |*elfclass| to the ELF file class.
 149 bool FindElfSegment(const void* elf_mapped_base, uint32_t segment_type,
 150                     const void** segment_start, int* segment_size,
 151                     int* elfclass);
 152
 153 // Convert an offset from an Elf header into a pointer to the mapped
 154 // address in the current process. Takes an extra template parameter
 155 // to specify the return type to avoid having to dynamic_cast the
 156 // result.
 157 template <typename ElfClass, typename T>
 158 const T* GetOffset(const typename ElfClass::Ehdr* elf_header,
 159                    typename ElfClass::Off offset);
 160
 161 // (derived from)
 162 // file_id.h: Return a unique identifier for a file
 163 //
 164
 165 static const size_t kMDGUIDSize = sizeof(MDGUID);
 166
 167 class FileID {
 168  public:
 169   // Load the identifier for the elf file mapped into memory at |base| into
 170   // |identifier|.  Return false if the identifier could not be created for the
 171   // file.
 172   static bool ElfFileIdentifierFromMappedFile(const void* base,
 173                                               uint8_t identifier[kMDGUIDSize]);
 174
 175   // Convert the |identifier| data to a NULL terminated string.  The string will
 176   // be formatted as a UUID (e.g., 22F065BB-FC9C-49F7-80FE-26A7CEBD7BCE).
 177   // The |buffer| should be at least 37 bytes long to receive all of the data
 178   // and termination.  Shorter buffers will contain truncated data.
 179   static void ConvertIdentifierToString(const uint8_t identifier[kMDGUIDSize],
 180                                         char* buffer, int buffer_length);
 181 };
 182
 183 template <typename ElfClass, typename T>
 184 const T* GetOffset(const typename ElfClass::Ehdr* elf_header,
 185                    typename ElfClass::Off offset) {
 186   return reinterpret_cast<const T*>(reinterpret_cast<uintptr_t>(elf_header) +
 187                                     offset);
 188 }
 189
 190 template <typename ElfClass>
 191 const typename ElfClass::Shdr* FindElfSectionByName(
 192     const char* name, typename ElfClass::Word section_type,
 193     const typename ElfClass::Shdr* sections, const char* section_names,
 194     const char* names_end, int nsection) {
 195   MOZ_ASSERT(name != NULL);
 196   MOZ_ASSERT(sections != NULL);
 197   MOZ_ASSERT(nsection > 0);
 198
 199   int name_len = strlen(name);
 200   if (name_len == 0) return NULL;
 201
 202   for (int i = 0; i < nsection; ++i) {
 203     const char* section_name = section_names + sections[i].sh_name;
 204     if (sections[i].sh_type == section_type &&
 205         names_end - section_name >= name_len + 1 &&
 206         strcmp(name, section_name) == 0) {
 207       return sections + i;
 208     }
 209   }
 210   return NULL;
 211 }
 212
 213 }  // namespace lul
 214
 215 // And finally, the external interface, offered to LulMain.cpp
 216 #include "LulElfExt.h"
 217
 218 #endif  // LulElfInt_h