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// Copyright (c) 2012, 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.
#include "common/linux/elfutils.h"
#include <assert.h>
#include <string.h>
#include "common/linux/linux_libc_support.h"
#include "common/linux/elfutils-inl.h"
namespace google_breakpad {
namespace {
template<typename ElfClass>
void FindElfClassSection(const char *elf_base,
const char *section_name,
typename ElfClass::Word section_type,
const void **section_start,
size_t *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);
const Ehdr* elf_header = reinterpret_cast<const Ehdr*>(elf_base);
assert(elf_header->e_ident[EI_CLASS] == ElfClass::kClass);
const Shdr* sections =
GetOffset<ElfClass, Shdr>(elf_header, elf_header->e_shoff);
const Shdr* section_names = sections + elf_header->e_shstrndx;
const char* names =
GetOffset<ElfClass, char>(elf_header, section_names->sh_offset);
const char *names_end = names + section_names->sh_size;
const Shdr* section =
FindElfSectionByName<ElfClass>(section_name, section_type,
sections, names, names_end,
elf_header->e_shnum);
if (section != NULL && section->sh_size > 0) {
*section_start = elf_base + section->sh_offset;
*section_size = section->sh_size;
}
}
template<typename ElfClass>
void FindElfClassSegment(const char *elf_base,
typename ElfClass::Word segment_type,
wasteful_vector<ElfSegment> *segments) {
typedef typename ElfClass::Ehdr Ehdr;
typedef typename ElfClass::Phdr Phdr;
assert(elf_base);
assert(segments);
assert(my_strncmp(elf_base, ELFMAG, SELFMAG) == 0);
const Ehdr* elf_header = reinterpret_cast<const Ehdr*>(elf_base);
assert(elf_header->e_ident[EI_CLASS] == ElfClass::kClass);
const Phdr* phdrs =
GetOffset<ElfClass, Phdr>(elf_header, elf_header->e_phoff);
for (int i = 0; i < elf_header->e_phnum; ++i) {
if (phdrs[i].p_type == segment_type) {
ElfSegment seg = {};
seg.start = elf_base + phdrs[i].p_offset;
seg.size = phdrs[i].p_filesz;
segments->push_back(seg);
}
}
}
} // namespace
bool IsValidElf(const void* elf_base) {
return my_strncmp(reinterpret_cast<const char*>(elf_base),
ELFMAG, SELFMAG) == 0;
}
int ElfClass(const void* elf_base) {
const ElfW(Ehdr)* elf_header =
reinterpret_cast<const ElfW(Ehdr)*>(elf_base);
return elf_header->e_ident[EI_CLASS];
}
bool FindElfSection(const void *elf_mapped_base,
const char *section_name,
uint32_t section_type,
const void **section_start,
size_t *section_size) {
assert(elf_mapped_base);
assert(section_start);
assert(section_size);
*section_start = NULL;
*section_size = 0;
if (!IsValidElf(elf_mapped_base))
return false;
int cls = ElfClass(elf_mapped_base);
const char* elf_base =
static_cast<const char*>(elf_mapped_base);
if (cls == ELFCLASS32) {
FindElfClassSection<ElfClass32>(elf_base, section_name, section_type,
section_start, section_size);
return *section_start != NULL;
} else if (cls == ELFCLASS64) {
FindElfClassSection<ElfClass64>(elf_base, section_name, section_type,
section_start, section_size);
return *section_start != NULL;
}
return false;
}
bool FindElfSegments(const void* elf_mapped_base,
uint32_t segment_type,
wasteful_vector<ElfSegment>* segments) {
assert(elf_mapped_base);
assert(segments);
if (!IsValidElf(elf_mapped_base))
return false;
int cls = ElfClass(elf_mapped_base);
const char* elf_base =
static_cast<const char*>(elf_mapped_base);
if (cls == ELFCLASS32) {
FindElfClassSegment<ElfClass32>(elf_base, segment_type, segments);
return true;
} else if (cls == ELFCLASS64) {
FindElfClassSegment<ElfClass64>(elf_base, segment_type, segments);
return true;
}
return false;
}
} // namespace google_breakpad
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