121 lines
3.8 KiB
C++
121 lines
3.8 KiB
C++
/*
|
|
* Copyright (C) 2015 The Android Open Source Project
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#define LOG_TAG "DEBUG"
|
|
|
|
#include <elf.h>
|
|
#include <stdint.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
#include <string>
|
|
|
|
#include <backtrace/Backtrace.h>
|
|
#include <android-base/stringprintf.h>
|
|
#include <log/log.h>
|
|
|
|
#include "elf_utils.h"
|
|
|
|
#define NOTE_ALIGN(size) ((size + 3) & ~3)
|
|
|
|
template <typename HdrType, typename PhdrType, typename NhdrType>
|
|
static bool get_build_id(
|
|
Backtrace* backtrace, uintptr_t base_addr, uint8_t* e_ident, std::string* build_id) {
|
|
HdrType hdr;
|
|
|
|
memcpy(&hdr.e_ident[0], e_ident, EI_NIDENT);
|
|
|
|
// First read the rest of the header.
|
|
if (backtrace->Read(base_addr + EI_NIDENT, reinterpret_cast<uint8_t*>(&hdr) + EI_NIDENT,
|
|
sizeof(HdrType) - EI_NIDENT) != sizeof(HdrType) - EI_NIDENT) {
|
|
return false;
|
|
}
|
|
|
|
for (size_t i = 0; i < hdr.e_phnum; i++) {
|
|
PhdrType phdr;
|
|
if (backtrace->Read(base_addr + hdr.e_phoff + i * hdr.e_phentsize,
|
|
reinterpret_cast<uint8_t*>(&phdr), sizeof(phdr)) != sizeof(phdr)) {
|
|
return false;
|
|
}
|
|
// Looking for the .note.gnu.build-id note.
|
|
if (phdr.p_type == PT_NOTE) {
|
|
size_t hdr_size = phdr.p_filesz;
|
|
uintptr_t addr = base_addr + phdr.p_offset;
|
|
while (hdr_size >= sizeof(NhdrType)) {
|
|
NhdrType nhdr;
|
|
if (backtrace->Read(addr, reinterpret_cast<uint8_t*>(&nhdr), sizeof(nhdr)) != sizeof(nhdr)) {
|
|
return false;
|
|
}
|
|
addr += sizeof(nhdr);
|
|
if (nhdr.n_type == NT_GNU_BUILD_ID) {
|
|
// Skip the name (which is the owner and should be "GNU").
|
|
addr += NOTE_ALIGN(nhdr.n_namesz);
|
|
uint8_t build_id_data[128];
|
|
if (nhdr.n_namesz > sizeof(build_id_data)) {
|
|
ALOGE("Possible corrupted note, name size value is too large: %u",
|
|
nhdr.n_namesz);
|
|
return false;
|
|
}
|
|
if (backtrace->Read(addr, build_id_data, nhdr.n_descsz) != nhdr.n_descsz) {
|
|
return false;
|
|
}
|
|
|
|
build_id->clear();
|
|
for (size_t bytes = 0; bytes < nhdr.n_descsz; bytes++) {
|
|
*build_id += android::base::StringPrintf("%02x", build_id_data[bytes]);
|
|
}
|
|
|
|
return true;
|
|
} else {
|
|
// Move past the extra note data.
|
|
hdr_size -= sizeof(nhdr);
|
|
size_t skip_bytes = NOTE_ALIGN(nhdr.n_namesz) + NOTE_ALIGN(nhdr.n_descsz);
|
|
addr += skip_bytes;
|
|
if (hdr_size < skip_bytes) {
|
|
break;
|
|
}
|
|
hdr_size -= skip_bytes;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool elf_get_build_id(Backtrace* backtrace, uintptr_t addr, std::string* build_id) {
|
|
// Read and verify the elf magic number first.
|
|
uint8_t e_ident[EI_NIDENT];
|
|
if (backtrace->Read(addr, e_ident, SELFMAG) != SELFMAG) {
|
|
return false;
|
|
}
|
|
|
|
if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
|
|
return false;
|
|
}
|
|
|
|
// Read the rest of EI_NIDENT.
|
|
if (backtrace->Read(addr + SELFMAG, e_ident + SELFMAG, EI_NIDENT - SELFMAG) != EI_NIDENT - SELFMAG) {
|
|
return false;
|
|
}
|
|
|
|
if (e_ident[EI_CLASS] == ELFCLASS32) {
|
|
return get_build_id<Elf32_Ehdr, Elf32_Phdr, Elf32_Nhdr>(backtrace, addr, e_ident, build_id);
|
|
} else if (e_ident[EI_CLASS] == ELFCLASS64) {
|
|
return get_build_id<Elf64_Ehdr, Elf64_Phdr, Elf64_Nhdr>(backtrace, addr, e_ident, build_id);
|
|
}
|
|
|
|
return false;
|
|
}
|