06f7a967be
Previously, metadata backups were stored at the end of the partition to make them easy to locate. On older devices where the super partition could span system/vendor partitions, we may want to leave the end of each partition free to store an AVB footer. To allow this, we now store geometry and metadata backups near the start of the partition instead. They are still positioned at a fixed offset. Bug: 116802789 Test: device boots after flashing new metadata Change-Id: Ib173f251a4a13e290adcc4ac5cfbeb030eacda30
103 lines
2.9 KiB
C++
103 lines
2.9 KiB
C++
/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <fcntl.h>
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#include <stdint.h>
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#include <sys/ioctl.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <android-base/file.h>
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#include <ext4_utils/ext4_utils.h>
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#include <openssl/sha.h>
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#include "utility.h"
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namespace android {
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namespace fs_mgr {
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bool GetDescriptorSize(int fd, uint64_t* size) {
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struct stat s;
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if (fstat(fd, &s) < 0) {
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PERROR << __PRETTY_FUNCTION__ << "fstat failed";
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return false;
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}
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if (S_ISBLK(s.st_mode)) {
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*size = get_block_device_size(fd);
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return *size != 0;
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}
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int64_t result = SeekFile64(fd, 0, SEEK_END);
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if (result == -1) {
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PERROR << __PRETTY_FUNCTION__ << "lseek failed";
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return false;
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}
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*size = result;
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return true;
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}
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int64_t SeekFile64(int fd, int64_t offset, int whence) {
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static_assert(sizeof(off_t) == sizeof(int64_t), "Need 64-bit lseek");
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return lseek(fd, offset, whence);
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}
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int64_t GetPrimaryGeometryOffset() {
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return 0;
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}
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int64_t GetBackupGeometryOffset() {
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return LP_METADATA_GEOMETRY_SIZE;
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}
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int64_t GetPrimaryMetadataOffset(const LpMetadataGeometry& geometry, uint32_t slot_number) {
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CHECK(slot_number < geometry.metadata_slot_count);
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int64_t offset = (LP_METADATA_GEOMETRY_SIZE * 2) + geometry.metadata_max_size * slot_number;
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CHECK(offset + geometry.metadata_max_size <=
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int64_t(geometry.first_logical_sector * LP_SECTOR_SIZE));
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return offset;
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}
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int64_t GetBackupMetadataOffset(const LpMetadataGeometry& geometry, uint32_t slot_number) {
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CHECK(slot_number < geometry.metadata_slot_count);
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int64_t start = LP_METADATA_GEOMETRY_SIZE * 2 +
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int64_t(geometry.metadata_max_size) * geometry.metadata_slot_count;
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return start + int64_t(geometry.metadata_max_size * slot_number);
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}
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void SHA256(const void* data, size_t length, uint8_t out[32]) {
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SHA256_CTX c;
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SHA256_Init(&c);
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SHA256_Update(&c, data, length);
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SHA256_Final(out, &c);
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}
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uint32_t SlotNumberForSlotSuffix(const std::string& suffix) {
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if (suffix.empty()) {
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return 0;
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}
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if (suffix.size() != 2 || suffix[0] != '_' || suffix[1] < 'a') {
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LERROR << __PRETTY_FUNCTION__ << "slot '" << suffix
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<< "' does not have a recognized format.";
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return 0;
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}
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return suffix[1] - 'a';
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}
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} // namespace fs_mgr
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} // namespace android
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