/thirdparty/breakpad/common/linux/file_id.cc
http://github.com/tomahawk-player/tomahawk · C++ · 281 lines · 187 code · 42 blank · 52 comment · 45 complexity · ec3ecc68b4edd3076c089b932caa213c MD5 · raw file
- // Copyright (c) 2006, Google Inc.
- // All rights reserved.
- //
- // Redistribution and use in source and binary forms, with or without
- // modification, are permitted provided that the following conditions are
- // met:
- //
- // * Redistributions of source code must retain the above copyright
- // notice, this list of conditions and the following disclaimer.
- // * Redistributions in binary form must reproduce the above
- // copyright notice, this list of conditions and the following disclaimer
- // in the documentation and/or other materials provided with the
- // distribution.
- // * Neither the name of Google Inc. nor the names of its
- // contributors may be used to endorse or promote products derived from
- // this software without specific prior written permission.
- //
- // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- //
- // file_id.cc: Return a unique identifier for a file
- //
- // See file_id.h for documentation
- //
- #include "common/linux/file_id.h"
- #include <arpa/inet.h>
- #include <assert.h>
- #if defined(__ANDROID__)
- #include <linux/elf.h>
- #include "client/linux/android_link.h"
- #else
- #include <elf.h>
- #include <link.h>
- #endif
- #include <string.h>
- #include <algorithm>
- #include "common/linux/linux_libc_support.h"
- #include "common/linux/memory_mapped_file.h"
- #include "third_party/lss/linux_syscall_support.h"
- namespace google_breakpad {
- #ifndef NT_GNU_BUILD_ID
- #define NT_GNU_BUILD_ID 3
- #endif
- FileID::FileID(const char* path) {
- strncpy(path_, path, sizeof(path_));
- }
- struct ElfClass32 {
- typedef Elf32_Ehdr Ehdr;
- typedef Elf32_Nhdr Nhdr;
- typedef Elf32_Shdr Shdr;
- static const int kClass = ELFCLASS32;
- };
- struct ElfClass64 {
- typedef Elf64_Ehdr Ehdr;
- typedef Elf64_Nhdr Nhdr;
- typedef Elf64_Shdr Shdr;
- static const int kClass = ELFCLASS64;
- };
- // These six functions are also used inside the crashed process, so be safe
- // and use the syscall/libc wrappers instead of direct syscalls or libc.
- template<typename ElfClass>
- static void FindElfClassSection(const char *elf_base,
- const char *section_name,
- uint32_t section_type,
- const void **section_start,
- int *section_size) {
- typedef typename ElfClass::Ehdr Ehdr;
- typedef typename ElfClass::Shdr Shdr;
- assert(elf_base);
- assert(section_start);
- assert(section_size);
- assert(my_strncmp(elf_base, ELFMAG, SELFMAG) == 0);
- int name_len = my_strlen(section_name);
- const Ehdr* elf_header = reinterpret_cast<const Ehdr*>(elf_base);
- assert(elf_header->e_ident[EI_CLASS] == ElfClass::kClass);
- const Shdr* sections =
- reinterpret_cast<const Shdr*>(elf_base + elf_header->e_shoff);
- const Shdr* string_section = sections + elf_header->e_shstrndx;
- const Shdr* section = NULL;
- for (int i = 0; i < elf_header->e_shnum; ++i) {
- if (sections[i].sh_type == section_type) {
- const char* current_section_name = (char*)(elf_base +
- string_section->sh_offset +
- sections[i].sh_name);
- if (!my_strncmp(current_section_name, section_name, name_len)) {
- section = §ions[i];
- break;
- }
- }
- }
- if (section != NULL && section->sh_size > 0) {
- *section_start = elf_base + section->sh_offset;
- *section_size = section->sh_size;
- }
- }
- // Attempt to find a section named |section_name| of type |section_type|
- // in the ELF binary data at |elf_mapped_base|. On success, returns true
- // and sets |*section_start| to point to the start of the section data,
- // and |*section_size| to the size of the section's data. If |elfclass|
- // is not NULL, set |*elfclass| to the ELF file class.
- static bool FindElfSection(const void *elf_mapped_base,
- const char *section_name,
- uint32_t section_type,
- const void **section_start,
- int *section_size,
- int *elfclass) {
- assert(elf_mapped_base);
- assert(section_start);
- assert(section_size);
- *section_start = NULL;
- *section_size = 0;
- const char* elf_base =
- static_cast<const char*>(elf_mapped_base);
- const ElfW(Ehdr)* elf_header =
- reinterpret_cast<const ElfW(Ehdr)*>(elf_base);
- if (my_strncmp(elf_base, ELFMAG, SELFMAG) != 0)
- return false;
- if (elfclass) {
- *elfclass = elf_header->e_ident[EI_CLASS];
- }
- if (elf_header->e_ident[EI_CLASS] == ELFCLASS32) {
- FindElfClassSection<ElfClass32>(elf_base, section_name, section_type,
- section_start, section_size);
- return *section_start != NULL;
- } else if (elf_header->e_ident[EI_CLASS] == ELFCLASS64) {
- FindElfClassSection<ElfClass64>(elf_base, section_name, section_type,
- section_start, section_size);
- return *section_start != NULL;
- }
- return false;
- }
- template<typename ElfClass>
- static bool ElfClassBuildIDNoteIdentifier(const void *section,
- uint8_t identifier[kMDGUIDSize]) {
- typedef typename ElfClass::Nhdr Nhdr;
- const Nhdr* note_header = reinterpret_cast<const Nhdr*>(section);
- if (note_header->n_type != NT_GNU_BUILD_ID ||
- note_header->n_descsz == 0) {
- return false;
- }
- const char* build_id = reinterpret_cast<const char*>(section) +
- sizeof(Nhdr) + note_header->n_namesz;
- // Copy as many bits of the build ID as will fit
- // into the GUID space.
- my_memset(identifier, 0, kMDGUIDSize);
- memcpy(identifier, build_id,
- std::min(kMDGUIDSize, (size_t)note_header->n_descsz));
- return true;
- }
- // Attempt to locate a .note.gnu.build-id section in an ELF binary
- // and copy as many bytes of it as will fit into |identifier|.
- static bool FindElfBuildIDNote(const void *elf_mapped_base,
- uint8_t identifier[kMDGUIDSize]) {
- void* note_section;
- int note_size, elfclass;
- if (!FindElfSection(elf_mapped_base, ".note.gnu.build-id", SHT_NOTE,
- (const void**)¬e_section, ¬e_size, &elfclass) ||
- note_size == 0) {
- return false;
- }
- if (elfclass == ELFCLASS32) {
- return ElfClassBuildIDNoteIdentifier<ElfClass32>(note_section, identifier);
- } else if (elfclass == ELFCLASS64) {
- return ElfClassBuildIDNoteIdentifier<ElfClass64>(note_section, identifier);
- }
- return false;
- }
- // Attempt to locate the .text section of an ELF binary and generate
- // a simple hash by XORing the first page worth of bytes into |identifier|.
- static bool HashElfTextSection(const void *elf_mapped_base,
- uint8_t identifier[kMDGUIDSize]) {
- void* text_section;
- int text_size;
- if (!FindElfSection(elf_mapped_base, ".text", SHT_PROGBITS,
- (const void**)&text_section, &text_size, NULL) ||
- text_size == 0) {
- return false;
- }
- my_memset(identifier, 0, kMDGUIDSize);
- const uint8_t* ptr = reinterpret_cast<const uint8_t*>(text_section);
- const uint8_t* ptr_end = ptr + std::min(text_size, 4096);
- while (ptr < ptr_end) {
- for (unsigned i = 0; i < kMDGUIDSize; i++)
- identifier[i] ^= ptr[i];
- ptr += kMDGUIDSize;
- }
- return true;
- }
- // static
- bool FileID::ElfFileIdentifierFromMappedFile(const void* base,
- uint8_t identifier[kMDGUIDSize]) {
- // Look for a build id note first.
- if (FindElfBuildIDNote(base, identifier))
- return true;
- // Fall back on hashing the first page of the text section.
- return HashElfTextSection(base, identifier);
- }
- bool FileID::ElfFileIdentifier(uint8_t identifier[kMDGUIDSize]) {
- MemoryMappedFile mapped_file(path_);
- if (!mapped_file.data()) // Should probably check if size >= ElfW(Ehdr)?
- return false;
- return ElfFileIdentifierFromMappedFile(mapped_file.data(), identifier);
- }
- // static
- void FileID::ConvertIdentifierToString(const uint8_t identifier[kMDGUIDSize],
- char* buffer, int buffer_length) {
- uint8_t identifier_swapped[kMDGUIDSize];
- // Endian-ness swap to match dump processor expectation.
- memcpy(identifier_swapped, identifier, kMDGUIDSize);
- uint32_t* data1 = reinterpret_cast<uint32_t*>(identifier_swapped);
- *data1 = htonl(*data1);
- uint16_t* data2 = reinterpret_cast<uint16_t*>(identifier_swapped + 4);
- *data2 = htons(*data2);
- uint16_t* data3 = reinterpret_cast<uint16_t*>(identifier_swapped + 6);
- *data3 = htons(*data3);
- int buffer_idx = 0;
- for (unsigned int idx = 0;
- (buffer_idx < buffer_length) && (idx < kMDGUIDSize);
- ++idx) {
- int hi = (identifier_swapped[idx] >> 4) & 0x0F;
- int lo = (identifier_swapped[idx]) & 0x0F;
- if (idx == 4 || idx == 6 || idx == 8 || idx == 10)
- buffer[buffer_idx++] = '-';
- buffer[buffer_idx++] = (hi >= 10) ? 'A' + hi - 10 : '0' + hi;
- buffer[buffer_idx++] = (lo >= 10) ? 'A' + lo - 10 : '0' + lo;
- }
- // NULL terminate
- buffer[(buffer_idx < buffer_length) ? buffer_idx : buffer_idx - 1] = 0;
- }
- } // namespace google_breakpad