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// Copyright 2011 Google LLC
//
// 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 LLC 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.
// elf_core_dump.cc: Implement google_breakpad::ElfCoreDump.
// See elf_core_dump.h for details.
#include "common/linux/elf_core_dump.h"
#include <stddef.h>
#include <string.h>
#include <unistd.h>
namespace google_breakpad {
// Implementation of ElfCoreDump::Note.
ElfCoreDump::Note::Note() {}
ElfCoreDump::Note::Note(const MemoryRange& content) : content_(content) {}
bool ElfCoreDump::Note::IsValid() const {
return GetHeader() != NULL;
}
const ElfCoreDump::Nhdr* ElfCoreDump::Note::GetHeader() const {
return content_.GetData<Nhdr>(0);
}
ElfCoreDump::Word ElfCoreDump::Note::GetType() const {
const Nhdr* header = GetHeader();
// 0 is not being used as a NOTE type.
return header ? header->n_type : 0;
}
MemoryRange ElfCoreDump::Note::GetName() const {
const Nhdr* header = GetHeader();
if (header) {
return content_.Subrange(sizeof(Nhdr), header->n_namesz);
}
return MemoryRange();
}
MemoryRange ElfCoreDump::Note::GetDescription() const {
const Nhdr* header = GetHeader();
if (header) {
return content_.Subrange(AlignedSize(sizeof(Nhdr) + header->n_namesz),
header->n_descsz);
}
return MemoryRange();
}
ElfCoreDump::Note ElfCoreDump::Note::GetNextNote() const {
MemoryRange next_content;
const Nhdr* header = GetHeader();
if (header) {
size_t next_offset = AlignedSize(sizeof(Nhdr) + header->n_namesz);
next_offset = AlignedSize(next_offset + header->n_descsz);
next_content =
content_.Subrange(next_offset, content_.length() - next_offset);
}
return Note(next_content);
}
// static
size_t ElfCoreDump::Note::AlignedSize(size_t size) {
size_t mask = sizeof(Word) - 1;
return (size + mask) & ~mask;
}
// Implementation of ElfCoreDump.
ElfCoreDump::ElfCoreDump() : proc_mem_fd_(-1) {}
ElfCoreDump::ElfCoreDump(const MemoryRange& content)
: content_(content), proc_mem_fd_(-1) {}
ElfCoreDump::~ElfCoreDump() {
if (proc_mem_fd_ != -1) {
close(proc_mem_fd_);
proc_mem_fd_ = -1;
}
}
void ElfCoreDump::SetContent(const MemoryRange& content) {
content_ = content;
}
void ElfCoreDump::SetProcMem(int fd) {
if (proc_mem_fd_ != -1) {
close(proc_mem_fd_);
}
proc_mem_fd_ = fd;
}
bool ElfCoreDump::IsValid() const {
const Ehdr* header = GetHeader();
return (header &&
header->e_ident[0] == ELFMAG0 &&
header->e_ident[1] == ELFMAG1 &&
header->e_ident[2] == ELFMAG2 &&
header->e_ident[3] == ELFMAG3 &&
header->e_ident[4] == kClass &&
header->e_version == EV_CURRENT &&
header->e_type == ET_CORE);
}
const ElfCoreDump::Ehdr* ElfCoreDump::GetHeader() const {
return content_.GetData<Ehdr>(0);
}
const ElfCoreDump::Phdr* ElfCoreDump::GetProgramHeader(unsigned index) const {
const Ehdr* header = GetHeader();
if (header) {
return reinterpret_cast<const Phdr*>(content_.GetArrayElement(
header->e_phoff, header->e_phentsize, index));
}
return NULL;
}
const ElfCoreDump::Phdr* ElfCoreDump::GetFirstProgramHeaderOfType(
Word type) const {
for (unsigned i = 0, n = GetProgramHeaderCount(); i < n; ++i) {
const Phdr* program = GetProgramHeader(i);
if (program->p_type == type) {
return program;
}
}
return NULL;
}
unsigned ElfCoreDump::GetProgramHeaderCount() const {
const Ehdr* header = GetHeader();
return header ? header->e_phnum : 0;
}
bool ElfCoreDump::CopyData(void* buffer, Addr virtual_address, size_t length) {
for (unsigned i = 0, n = GetProgramHeaderCount(); i < n; ++i) {
const Phdr* program = GetProgramHeader(i);
if (program->p_type != PT_LOAD)
continue;
size_t offset_in_segment = virtual_address - program->p_vaddr;
if (virtual_address >= program->p_vaddr &&
offset_in_segment < program->p_filesz) {
const void* data =
content_.GetData(program->p_offset + offset_in_segment, length);
if (data) {
memcpy(buffer, data, length);
return true;
}
}
}
/* fallback: if available, read from /proc/<pid>/mem */
if (proc_mem_fd_ != -1) {
off_t offset = virtual_address;
ssize_t r = pread(proc_mem_fd_, buffer, length, offset);
if (r < ssize_t(length)) {
return false;
}
return true;
}
return false;
}
ElfCoreDump::Note ElfCoreDump::GetFirstNote() const {
MemoryRange note_content;
const Phdr* program_header = GetFirstProgramHeaderOfType(PT_NOTE);
if (program_header) {
note_content = content_.Subrange(program_header->p_offset,
program_header->p_filesz);
}
return Note(note_content);
}
} // namespace google_breakpad
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