1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/toolkit/crashreporter/google-breakpad/src/common/linux/file_id.cc Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,195 @@
1.4 +// Copyright (c) 2006, Google Inc.
1.5 +// All rights reserved.
1.6 +//
1.7 +// Redistribution and use in source and binary forms, with or without
1.8 +// modification, are permitted provided that the following conditions are
1.9 +// met:
1.10 +//
1.11 +// * Redistributions of source code must retain the above copyright
1.12 +// notice, this list of conditions and the following disclaimer.
1.13 +// * Redistributions in binary form must reproduce the above
1.14 +// copyright notice, this list of conditions and the following disclaimer
1.15 +// in the documentation and/or other materials provided with the
1.16 +// distribution.
1.17 +// * Neither the name of Google Inc. nor the names of its
1.18 +// contributors may be used to endorse or promote products derived from
1.19 +// this software without specific prior written permission.
1.20 +//
1.21 +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
1.22 +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
1.23 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
1.24 +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
1.25 +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
1.26 +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
1.27 +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1.28 +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1.29 +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.30 +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
1.31 +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.32 +//
1.33 +// file_id.cc: Return a unique identifier for a file
1.34 +//
1.35 +// See file_id.h for documentation
1.36 +//
1.37 +
1.38 +#include "common/linux/file_id.h"
1.39 +
1.40 +#include <arpa/inet.h>
1.41 +#include <assert.h>
1.42 +#include <string.h>
1.43 +
1.44 +#include <algorithm>
1.45 +
1.46 +#include "common/linux/elfutils.h"
1.47 +#include "common/linux/linux_libc_support.h"
1.48 +#include "common/linux/memory_mapped_file.h"
1.49 +#include "third_party/lss/linux_syscall_support.h"
1.50 +
1.51 +namespace google_breakpad {
1.52 +
1.53 +#ifndef NT_GNU_BUILD_ID
1.54 +#define NT_GNU_BUILD_ID 3
1.55 +#endif
1.56 +
1.57 +FileID::FileID(const char* path) {
1.58 + strncpy(path_, path, sizeof(path_));
1.59 +}
1.60 +
1.61 +// ELF note name and desc are 32-bits word padded.
1.62 +#define NOTE_PADDING(a) ((a + 3) & ~3)
1.63 +
1.64 +// These functions are also used inside the crashed process, so be safe
1.65 +// and use the syscall/libc wrappers instead of direct syscalls or libc.
1.66 +
1.67 +template<typename ElfClass>
1.68 +static bool ElfClassBuildIDNoteIdentifier(const void *section, int length,
1.69 + uint8_t identifier[kMDGUIDSize]) {
1.70 + typedef typename ElfClass::Nhdr Nhdr;
1.71 +
1.72 + const void* section_end = reinterpret_cast<const char*>(section) + length;
1.73 + const Nhdr* note_header = reinterpret_cast<const Nhdr*>(section);
1.74 + while (reinterpret_cast<const void *>(note_header) < section_end) {
1.75 + if (note_header->n_type == NT_GNU_BUILD_ID)
1.76 + break;
1.77 + note_header = reinterpret_cast<const Nhdr*>(
1.78 + reinterpret_cast<const char*>(note_header) + sizeof(Nhdr) +
1.79 + NOTE_PADDING(note_header->n_namesz) +
1.80 + NOTE_PADDING(note_header->n_descsz));
1.81 + }
1.82 + if (reinterpret_cast<const void *>(note_header) >= section_end ||
1.83 + note_header->n_descsz == 0) {
1.84 + return false;
1.85 + }
1.86 +
1.87 + const char* build_id = reinterpret_cast<const char*>(note_header) +
1.88 + sizeof(Nhdr) + NOTE_PADDING(note_header->n_namesz);
1.89 + // Copy as many bits of the build ID as will fit
1.90 + // into the GUID space.
1.91 + my_memset(identifier, 0, kMDGUIDSize);
1.92 + memcpy(identifier, build_id,
1.93 + std::min(kMDGUIDSize, (size_t)note_header->n_descsz));
1.94 +
1.95 + return true;
1.96 +}
1.97 +
1.98 +// Attempt to locate a .note.gnu.build-id section in an ELF binary
1.99 +// and copy as many bytes of it as will fit into |identifier|.
1.100 +static bool FindElfBuildIDNote(const void *elf_mapped_base,
1.101 + uint8_t identifier[kMDGUIDSize]) {
1.102 + void* note_section;
1.103 + int note_size, elfclass;
1.104 + if ((!FindElfSegment(elf_mapped_base, PT_NOTE,
1.105 + (const void**)¬e_section, ¬e_size, &elfclass) ||
1.106 + note_size == 0) &&
1.107 + (!FindElfSection(elf_mapped_base, ".note.gnu.build-id", SHT_NOTE,
1.108 + (const void**)¬e_section, ¬e_size, &elfclass) ||
1.109 + note_size == 0)) {
1.110 + return false;
1.111 + }
1.112 +
1.113 + if (elfclass == ELFCLASS32) {
1.114 + return ElfClassBuildIDNoteIdentifier<ElfClass32>(note_section, note_size,
1.115 + identifier);
1.116 + } else if (elfclass == ELFCLASS64) {
1.117 + return ElfClassBuildIDNoteIdentifier<ElfClass64>(note_section, note_size,
1.118 + identifier);
1.119 + }
1.120 +
1.121 + return false;
1.122 +}
1.123 +
1.124 +// Attempt to locate the .text section of an ELF binary and generate
1.125 +// a simple hash by XORing the first page worth of bytes into |identifier|.
1.126 +static bool HashElfTextSection(const void *elf_mapped_base,
1.127 + uint8_t identifier[kMDGUIDSize]) {
1.128 + void* text_section;
1.129 + int text_size;
1.130 + if (!FindElfSection(elf_mapped_base, ".text", SHT_PROGBITS,
1.131 + (const void**)&text_section, &text_size, NULL) ||
1.132 + text_size == 0) {
1.133 + return false;
1.134 + }
1.135 +
1.136 + my_memset(identifier, 0, kMDGUIDSize);
1.137 + const uint8_t* ptr = reinterpret_cast<const uint8_t*>(text_section);
1.138 + const uint8_t* ptr_end = ptr + std::min(text_size, 4096);
1.139 + while (ptr < ptr_end) {
1.140 + for (unsigned i = 0; i < kMDGUIDSize; i++)
1.141 + identifier[i] ^= ptr[i];
1.142 + ptr += kMDGUIDSize;
1.143 + }
1.144 + return true;
1.145 +}
1.146 +
1.147 +// static
1.148 +bool FileID::ElfFileIdentifierFromMappedFile(const void* base,
1.149 + uint8_t identifier[kMDGUIDSize]) {
1.150 + // Look for a build id note first.
1.151 + if (FindElfBuildIDNote(base, identifier))
1.152 + return true;
1.153 +
1.154 + // Fall back on hashing the first page of the text section.
1.155 + return HashElfTextSection(base, identifier);
1.156 +}
1.157 +
1.158 +bool FileID::ElfFileIdentifier(uint8_t identifier[kMDGUIDSize]) {
1.159 + MemoryMappedFile mapped_file(path_);
1.160 + if (!mapped_file.data()) // Should probably check if size >= ElfW(Ehdr)?
1.161 + return false;
1.162 +
1.163 + return ElfFileIdentifierFromMappedFile(mapped_file.data(), identifier);
1.164 +}
1.165 +
1.166 +// static
1.167 +void FileID::ConvertIdentifierToString(const uint8_t identifier[kMDGUIDSize],
1.168 + char* buffer, int buffer_length) {
1.169 + uint8_t identifier_swapped[kMDGUIDSize];
1.170 +
1.171 + // Endian-ness swap to match dump processor expectation.
1.172 + memcpy(identifier_swapped, identifier, kMDGUIDSize);
1.173 + uint32_t* data1 = reinterpret_cast<uint32_t*>(identifier_swapped);
1.174 + *data1 = htonl(*data1);
1.175 + uint16_t* data2 = reinterpret_cast<uint16_t*>(identifier_swapped + 4);
1.176 + *data2 = htons(*data2);
1.177 + uint16_t* data3 = reinterpret_cast<uint16_t*>(identifier_swapped + 6);
1.178 + *data3 = htons(*data3);
1.179 +
1.180 + int buffer_idx = 0;
1.181 + for (unsigned int idx = 0;
1.182 + (buffer_idx < buffer_length) && (idx < kMDGUIDSize);
1.183 + ++idx) {
1.184 + int hi = (identifier_swapped[idx] >> 4) & 0x0F;
1.185 + int lo = (identifier_swapped[idx]) & 0x0F;
1.186 +
1.187 + if (idx == 4 || idx == 6 || idx == 8 || idx == 10)
1.188 + buffer[buffer_idx++] = '-';
1.189 +
1.190 + buffer[buffer_idx++] = (hi >= 10) ? 'A' + hi - 10 : '0' + hi;
1.191 + buffer[buffer_idx++] = (lo >= 10) ? 'A' + lo - 10 : '0' + lo;
1.192 + }
1.193 +
1.194 + // NULL terminate
1.195 + buffer[(buffer_idx < buffer_length) ? buffer_idx : buffer_idx - 1] = 0;
1.196 +}
1.197 +
1.198 +} // namespace google_breakpad
