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platform_bootable_recovery/updater/blockimg.cpp
xunchang 53158e51d0 Fix potential size overflow in blockimg.cpp 
Switch to 64 bit integers since the size of the entire src/tgt images may
not fit in size_t of ILP32.

There are other theoretical overflow cases in memory allocation and I/O
functions. However, they reside within a single transfer command and are
less likely to happen. I will evaluate and address them in separate
cls.

Test: unit tests pass
Bug: 122461124
Change-Id: Ib719ee695920877458fcfaa25c6ac058a5bbabf2
2019-01-17 09:26:12 -08:00

2271 lines
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/*
* Copyright (C) 2014 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.
*/
#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <linux/fs.h>
#include <pthread.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#include <functional>
#include <limits>
#include <memory>
#include <string>
#include <unordered_map>
#include <vector>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <applypatch/applypatch.h>
#include <brotli/decode.h>
#include <fec/io.h>
#include <openssl/sha.h>
#include <private/android_filesystem_config.h>
#include <verity/hash_tree_builder.h>
#include <ziparchive/zip_archive.h>
#include "edify/expr.h"
#include "otautil/dirutil.h"
#include "otautil/error_code.h"
#include "otautil/paths.h"
#include "otautil/print_sha1.h"
#include "otautil/rangeset.h"
#include "private/commands.h"
#include "updater/install.h"
#include "updater/updater.h"
// Set this to 0 to interpret 'erase' transfers to mean do a
// BLKDISCARD ioctl (the normal behavior). Set to 1 to interpret
// erase to mean fill the region with zeroes.
#define DEBUG_ERASE 0
static constexpr size_t BLOCKSIZE = 4096;
static constexpr mode_t STASH_DIRECTORY_MODE = 0700;
static constexpr mode_t STASH_FILE_MODE = 0600;
static constexpr mode_t MARKER_DIRECTORY_MODE = 0700;
static CauseCode failure_type = kNoCause;
static bool is_retry = false;
static std::unordered_map<std::string, RangeSet> stash_map;
static void DeleteLastCommandFile() {
const std::string& last_command_file = Paths::Get().last_command_file();
if (unlink(last_command_file.c_str()) == -1 && errno != ENOENT) {
PLOG(ERROR) << "Failed to unlink: " << last_command_file;
}
}
// Parse the last command index of the last update and save the result to |last_command_index|.
// Return true if we successfully read the index.
static bool ParseLastCommandFile(size_t* last_command_index) {
const std::string& last_command_file = Paths::Get().last_command_file();
android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(last_command_file.c_str(), O_RDONLY)));
if (fd == -1) {
if (errno != ENOENT) {
PLOG(ERROR) << "Failed to open " << last_command_file;
return false;
}
LOG(INFO) << last_command_file << " doesn't exist.";
return false;
}
// Now that the last_command file exists, parse the last command index of previous update.
std::string content;
if (!android::base::ReadFdToString(fd.get(), &content)) {
LOG(ERROR) << "Failed to read: " << last_command_file;
return false;
}
std::vector<std::string> lines = android::base::Split(android::base::Trim(content), "\n");
if (lines.size() != 2) {
LOG(ERROR) << "Unexpected line counts in last command file: " << content;
return false;
}
if (!android::base::ParseUint(lines[0], last_command_index)) {
LOG(ERROR) << "Failed to parse integer in: " << lines[0];
return false;
}
return true;
}
static bool FsyncDir(const std::string& dirname) {
android::base::unique_fd dfd(TEMP_FAILURE_RETRY(open(dirname.c_str(), O_RDONLY | O_DIRECTORY)));
if (dfd == -1) {
failure_type = errno == EIO ? kEioFailure : kFileOpenFailure;
PLOG(ERROR) << "Failed to open " << dirname;
return false;
}
if (fsync(dfd) == -1) {
failure_type = errno == EIO ? kEioFailure : kFsyncFailure;
PLOG(ERROR) << "Failed to fsync " << dirname;
return false;
}
return true;
}
// Update the last executed command index in the last_command_file.
static bool UpdateLastCommandIndex(size_t command_index, const std::string& command_string) {
const std::string& last_command_file = Paths::Get().last_command_file();
std::string last_command_tmp = last_command_file + ".tmp";
std::string content = std::to_string(command_index) + "\n" + command_string;
android::base::unique_fd wfd(
TEMP_FAILURE_RETRY(open(last_command_tmp.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0660)));
if (wfd == -1 || !android::base::WriteStringToFd(content, wfd)) {
PLOG(ERROR) << "Failed to update last command";
return false;
}
if (fsync(wfd) == -1) {
PLOG(ERROR) << "Failed to fsync " << last_command_tmp;
return false;
}
if (chown(last_command_tmp.c_str(), AID_SYSTEM, AID_SYSTEM) == -1) {
PLOG(ERROR) << "Failed to change owner for " << last_command_tmp;
return false;
}
if (rename(last_command_tmp.c_str(), last_command_file.c_str()) == -1) {
PLOG(ERROR) << "Failed to rename" << last_command_tmp;
return false;
}
if (!FsyncDir(android::base::Dirname(last_command_file))) {
return false;
}
return true;
}
bool SetUpdatedMarker(const std::string& marker) {
auto dirname = android::base::Dirname(marker);
auto res = mkdir(dirname.c_str(), MARKER_DIRECTORY_MODE);
if (res == -1 && errno != EEXIST) {
PLOG(ERROR) << "Failed to create directory for marker: " << dirname;
return false;
}
if (!android::base::WriteStringToFile("", marker)) {
PLOG(ERROR) << "Failed to write to marker file " << marker;
return false;
}
if (!FsyncDir(dirname)) {
return false;
}
LOG(INFO) << "Wrote updated marker to " << marker;
return true;
}
static bool discard_blocks(int fd, off64_t offset, uint64_t size, bool force = false) {
// Don't discard blocks unless the update is a retry run or force == true
if (!is_retry && !force) {
return true;
}
uint64_t args[2] = { static_cast<uint64_t>(offset), size };
if (ioctl(fd, BLKDISCARD, &args) == -1) {
// On devices that does not support BLKDISCARD, ignore the error.
if (errno == EOPNOTSUPP) {
return true;
}
PLOG(ERROR) << "BLKDISCARD ioctl failed";
return false;
}
return true;
}
static bool check_lseek(int fd, off64_t offset, int whence) {
off64_t rc = TEMP_FAILURE_RETRY(lseek64(fd, offset, whence));
if (rc == -1) {
failure_type = kLseekFailure;
PLOG(ERROR) << "lseek64 failed";
return false;
}
return true;
}
static void allocate(size_t size, std::vector<uint8_t>* buffer) {
// If the buffer's big enough, reuse it.
if (size <= buffer->size()) return;
buffer->resize(size);
}
/**
* RangeSinkWriter reads data from the given FD, and writes them to the destination specified by the
* given RangeSet.
*/
class RangeSinkWriter {
public:
RangeSinkWriter(int fd, const RangeSet& tgt)
: fd_(fd),
tgt_(tgt),
next_range_(0),
current_range_left_(0),
bytes_written_(0) {
CHECK_NE(tgt.size(), static_cast<size_t>(0));
};
bool Finished() const {
return next_range_ == tgt_.size() && current_range_left_ == 0;
}
size_t AvailableSpace() const {
return tgt_.blocks() * BLOCKSIZE - bytes_written_;
}
// Return number of bytes written; and 0 indicates a writing failure.
size_t Write(const uint8_t* data, size_t size) {
if (Finished()) {
LOG(ERROR) << "range sink write overrun; can't write " << size << " bytes";
return 0;
}
size_t written = 0;
while (size > 0) {
// Move to the next range as needed.
if (!SeekToOutputRange()) {
break;
}
size_t write_now = size;
if (current_range_left_ < write_now) {
write_now = current_range_left_;
}
if (!android::base::WriteFully(fd_, data, write_now)) {
failure_type = errno == EIO ? kEioFailure : kFwriteFailure;
PLOG(ERROR) << "Failed to write " << write_now << " bytes of data";
break;
}
data += write_now;
size -= write_now;
current_range_left_ -= write_now;
written += write_now;
}
bytes_written_ += written;
return written;
}
size_t BytesWritten() const {
return bytes_written_;
}
private:
// Set up the output cursor, move to next range if needed.
bool SeekToOutputRange() {
// We haven't finished the current range yet.
if (current_range_left_ != 0) {
return true;
}
// We can't write any more; let the write function return how many bytes have been written
// so far.
if (next_range_ >= tgt_.size()) {
return false;
}
const Range& range = tgt_[next_range_];
off64_t offset = static_cast<off64_t>(range.first) * BLOCKSIZE;
current_range_left_ = (range.second - range.first) * BLOCKSIZE;
next_range_++;
if (!discard_blocks(fd_, offset, current_range_left_)) {
return false;
}
if (!check_lseek(fd_, offset, SEEK_SET)) {
return false;
}
return true;
}
// The output file descriptor.
int fd_;
// The destination ranges for the data.
const RangeSet& tgt_;
// The next range that we should write to.
size_t next_range_;
// The number of bytes to write before moving to the next range.
size_t current_range_left_;
// Total bytes written by the writer.
size_t bytes_written_;
};
/**
* All of the data for all the 'new' transfers is contained in one file in the update package,
* concatenated together in the order in which transfers.list will need it. We want to stream it out
* of the archive (it's compressed) without writing it to a temp file, but we can't write each
* section until it's that transfer's turn to go.
*
* To achieve this, we expand the new data from the archive in a background thread, and block that
* threads 'receive uncompressed data' function until the main thread has reached a point where we
* want some new data to be written. We signal the background thread with the destination for the
* data and block the main thread, waiting for the background thread to complete writing that
* section. Then it signals the main thread to wake up and goes back to blocking waiting for a
* transfer.
*
* NewThreadInfo is the struct used to pass information back and forth between the two threads. When
* the main thread wants some data written, it sets writer to the destination location and signals
* the condition. When the background thread is done writing, it clears writer and signals the
* condition again.
*/
struct NewThreadInfo {
ZipArchiveHandle za;
ZipEntry entry;
bool brotli_compressed;
std::unique_ptr<RangeSinkWriter> writer;
BrotliDecoderState* brotli_decoder_state;
bool receiver_available;
pthread_mutex_t mu;
pthread_cond_t cv;
};
static bool receive_new_data(const uint8_t* data, size_t size, void* cookie) {
NewThreadInfo* nti = static_cast<NewThreadInfo*>(cookie);
while (size > 0) {
// Wait for nti->writer to be non-null, indicating some of this data is wanted.
pthread_mutex_lock(&nti->mu);
while (nti->writer == nullptr) {
// End the new data receiver if we encounter an error when performing block image update.
if (!nti->receiver_available) {
pthread_mutex_unlock(&nti->mu);
return false;
}
pthread_cond_wait(&nti->cv, &nti->mu);
}
pthread_mutex_unlock(&nti->mu);
// At this point nti->writer is set, and we own it. The main thread is waiting for it to
// disappear from nti.
size_t write_now = std::min(size, nti->writer->AvailableSpace());
if (nti->writer->Write(data, write_now) != write_now) {
LOG(ERROR) << "Failed to write " << write_now << " bytes.";
return false;
}
data += write_now;
size -= write_now;
if (nti->writer->Finished()) {
// We have written all the bytes desired by this writer.
pthread_mutex_lock(&nti->mu);
nti->writer = nullptr;
pthread_cond_broadcast(&nti->cv);
pthread_mutex_unlock(&nti->mu);
}
}
return true;
}
static bool receive_brotli_new_data(const uint8_t* data, size_t size, void* cookie) {
NewThreadInfo* nti = static_cast<NewThreadInfo*>(cookie);
while (size > 0 || BrotliDecoderHasMoreOutput(nti->brotli_decoder_state)) {
// Wait for nti->writer to be non-null, indicating some of this data is wanted.
pthread_mutex_lock(&nti->mu);
while (nti->writer == nullptr) {
// End the receiver if we encounter an error when performing block image update.
if (!nti->receiver_available) {
pthread_mutex_unlock(&nti->mu);
return false;
}
pthread_cond_wait(&nti->cv, &nti->mu);
}
pthread_mutex_unlock(&nti->mu);
// At this point nti->writer is set, and we own it. The main thread is waiting for it to
// disappear from nti.
size_t buffer_size = std::min<size_t>(32768, nti->writer->AvailableSpace());
if (buffer_size == 0) {
LOG(ERROR) << "No space left in output range";
return false;
}
uint8_t buffer[buffer_size];
size_t available_in = size;
size_t available_out = buffer_size;
uint8_t* next_out = buffer;
// The brotli decoder will update |data|, |available_in|, |next_out| and |available_out|.
BrotliDecoderResult result = BrotliDecoderDecompressStream(
nti->brotli_decoder_state, &available_in, &data, &available_out, &next_out, nullptr);
if (result == BROTLI_DECODER_RESULT_ERROR) {
LOG(ERROR) << "Decompression failed with "
<< BrotliDecoderErrorString(BrotliDecoderGetErrorCode(nti->brotli_decoder_state));
return false;
}
LOG(DEBUG) << "bytes to write: " << buffer_size - available_out << ", bytes consumed "
<< size - available_in << ", decoder status " << result;
size_t write_now = buffer_size - available_out;
if (nti->writer->Write(buffer, write_now) != write_now) {
LOG(ERROR) << "Failed to write " << write_now << " bytes.";
return false;
}
// Update the remaining size. The input data ptr is already updated by brotli decoder function.
size = available_in;
if (nti->writer->Finished()) {
// We have written all the bytes desired by this writer.
pthread_mutex_lock(&nti->mu);
nti->writer = nullptr;
pthread_cond_broadcast(&nti->cv);
pthread_mutex_unlock(&nti->mu);
}
}
return true;
}
static void* unzip_new_data(void* cookie) {
NewThreadInfo* nti = static_cast<NewThreadInfo*>(cookie);
if (nti->brotli_compressed) {
ProcessZipEntryContents(nti->za, &nti->entry, receive_brotli_new_data, nti);
} else {
ProcessZipEntryContents(nti->za, &nti->entry, receive_new_data, nti);
}
pthread_mutex_lock(&nti->mu);
nti->receiver_available = false;
if (nti->writer != nullptr) {
pthread_cond_broadcast(&nti->cv);
}
pthread_mutex_unlock(&nti->mu);
return nullptr;
}
static int ReadBlocks(const RangeSet& src, std::vector<uint8_t>* buffer, int fd) {
size_t p = 0;
for (const auto& [begin, end] : src) {
if (!check_lseek(fd, static_cast<off64_t>(begin) * BLOCKSIZE, SEEK_SET)) {
return -1;
}
size_t size = (end - begin) * BLOCKSIZE;
if (!android::base::ReadFully(fd, buffer->data() + p, size)) {
failure_type = errno == EIO ? kEioFailure : kFreadFailure;
PLOG(ERROR) << "Failed to read " << size << " bytes of data";
return -1;
}
p += size;
}
return 0;
}
static int WriteBlocks(const RangeSet& tgt, const std::vector<uint8_t>& buffer, int fd) {
size_t written = 0;
for (const auto& [begin, end] : tgt) {
off64_t offset = static_cast<off64_t>(begin) * BLOCKSIZE;
size_t size = (end - begin) * BLOCKSIZE;
if (!discard_blocks(fd, offset, size)) {
return -1;
}
if (!check_lseek(fd, offset, SEEK_SET)) {
return -1;
}
if (!android::base::WriteFully(fd, buffer.data() + written, size)) {
failure_type = errno == EIO ? kEioFailure : kFwriteFailure;
PLOG(ERROR) << "Failed to write " << size << " bytes of data";
return -1;
}
written += size;
}
return 0;
}
// Parameters for transfer list command functions
struct CommandParameters {
std::vector<std::string> tokens;
size_t cpos;
std::string cmdname;
std::string cmdline;
std::string freestash;
std::string stashbase;
bool canwrite;
int createdstash;
android::base::unique_fd fd;
bool foundwrites;
bool isunresumable;
int version;
size_t written;
size_t stashed;
NewThreadInfo nti;
pthread_t thread;
std::vector<uint8_t> buffer;
uint8_t* patch_start;
bool target_verified; // The target blocks have expected contents already.
};
// Print the hash in hex for corrupted source blocks (excluding the stashed blocks which is
// handled separately).
static void PrintHashForCorruptedSourceBlocks(const CommandParameters& params,
const std::vector<uint8_t>& buffer) {
LOG(INFO) << "unexpected contents of source blocks in cmd:\n" << params.cmdline;
CHECK(params.tokens[0] == "move" || params.tokens[0] == "bsdiff" ||
params.tokens[0] == "imgdiff");
size_t pos = 0;
// Command example:
// move <onehash> <tgt_range> <src_blk_count> <src_range> [<loc_range> <stashed_blocks>]
// bsdiff <offset> <len> <src_hash> <tgt_hash> <tgt_range> <src_blk_count> <src_range>
// [<loc_range> <stashed_blocks>]
if (params.tokens[0] == "move") {
// src_range for move starts at the 4th position.
if (params.tokens.size() < 5) {
LOG(ERROR) << "failed to parse source range in cmd:\n" << params.cmdline;
return;
}
pos = 4;
} else {
// src_range for diff starts at the 7th position.
if (params.tokens.size() < 8) {
LOG(ERROR) << "failed to parse source range in cmd:\n" << params.cmdline;
return;
}
pos = 7;
}
// Source blocks in stash only, no work to do.
if (params.tokens[pos] == "-") {
return;
}
RangeSet src = RangeSet::Parse(params.tokens[pos++]);
if (!src) {
LOG(ERROR) << "Failed to parse range in " << params.cmdline;
return;
}
RangeSet locs;
// If there's no stashed blocks, content in the buffer is consecutive and has the same
// order as the source blocks.
if (pos == params.tokens.size()) {
locs = RangeSet(std::vector<Range>{ Range{ 0, src.blocks() } });
} else {
// Otherwise, the next token is the offset of the source blocks in the target range.
// Example: for the tokens <4,63946,63947,63948,63979> <4,6,7,8,39> <stashed_blocks>;
// We want to print SHA-1 for the data in buffer[6], buffer[8], buffer[9] ... buffer[38];
// this corresponds to the 32 src blocks #63946, #63948, #63949 ... #63978.
locs = RangeSet::Parse(params.tokens[pos++]);
CHECK_EQ(src.blocks(), locs.blocks());
}
LOG(INFO) << "printing hash in hex for " << src.blocks() << " source blocks";
for (size_t i = 0; i < src.blocks(); i++) {
size_t block_num = src.GetBlockNumber(i);
size_t buffer_index = locs.GetBlockNumber(i);
CHECK_LE((buffer_index + 1) * BLOCKSIZE, buffer.size());
uint8_t digest[SHA_DIGEST_LENGTH];
SHA1(buffer.data() + buffer_index * BLOCKSIZE, BLOCKSIZE, digest);
std::string hexdigest = print_sha1(digest);
LOG(INFO) << " block number: " << block_num << ", SHA-1: " << hexdigest;
}
}
// If the calculated hash for the whole stash doesn't match the stash id, print the SHA-1
// in hex for each block.
static void PrintHashForCorruptedStashedBlocks(const std::string& id,
const std::vector<uint8_t>& buffer,
const RangeSet& src) {
LOG(INFO) << "printing hash in hex for stash_id: " << id;
CHECK_EQ(src.blocks() * BLOCKSIZE, buffer.size());
for (size_t i = 0; i < src.blocks(); i++) {
size_t block_num = src.GetBlockNumber(i);
uint8_t digest[SHA_DIGEST_LENGTH];
SHA1(buffer.data() + i * BLOCKSIZE, BLOCKSIZE, digest);
std::string hexdigest = print_sha1(digest);
LOG(INFO) << " block number: " << block_num << ", SHA-1: " << hexdigest;
}
}
// If the stash file doesn't exist, read the source blocks this stash contains and print the
// SHA-1 for these blocks.
static void PrintHashForMissingStashedBlocks(const std::string& id, int fd) {
if (stash_map.find(id) == stash_map.end()) {
LOG(ERROR) << "No stash saved for id: " << id;
return;
}
LOG(INFO) << "print hash in hex for source blocks in missing stash: " << id;
const RangeSet& src = stash_map[id];
std::vector<uint8_t> buffer(src.blocks() * BLOCKSIZE);
if (ReadBlocks(src, &buffer, fd) == -1) {
LOG(ERROR) << "failed to read source blocks for stash: " << id;
return;
}
PrintHashForCorruptedStashedBlocks(id, buffer, src);
}
static int VerifyBlocks(const std::string& expected, const std::vector<uint8_t>& buffer,
const size_t blocks, bool printerror) {
uint8_t digest[SHA_DIGEST_LENGTH];
const uint8_t* data = buffer.data();
SHA1(data, blocks * BLOCKSIZE, digest);
std::string hexdigest = print_sha1(digest);
if (hexdigest != expected) {
if (printerror) {
LOG(ERROR) << "failed to verify blocks (expected " << expected << ", read " << hexdigest
<< ")";
}
return -1;
}
return 0;
}
static std::string GetStashFileName(const std::string& base, const std::string& id,
const std::string& postfix) {
if (base.empty()) {
return "";
}
std::string filename = Paths::Get().stash_directory_base() + "/" + base;
if (id.empty() && postfix.empty()) {
return filename;
}
return filename + "/" + id + postfix;
}
// Does a best effort enumeration of stash files. Ignores possible non-file items in the stash
// directory and continues despite of errors. Calls the 'callback' function for each file.
static void EnumerateStash(const std::string& dirname,
const std::function<void(const std::string&)>& callback) {
if (dirname.empty()) return;
std::unique_ptr<DIR, decltype(&closedir)> directory(opendir(dirname.c_str()), closedir);
if (directory == nullptr) {
if (errno != ENOENT) {
PLOG(ERROR) << "opendir \"" << dirname << "\" failed";
}
return;
}
dirent* item;
while ((item = readdir(directory.get())) != nullptr) {
if (item->d_type != DT_REG) continue;
callback(dirname + "/" + item->d_name);
}
}
// Deletes the stash directory and all files in it. Assumes that it only
// contains files. There is nothing we can do about unlikely, but possible
// errors, so they are merely logged.
static void DeleteFile(const std::string& fn) {
if (fn.empty()) return;
LOG(INFO) << "deleting " << fn;
if (unlink(fn.c_str()) == -1 && errno != ENOENT) {
PLOG(ERROR) << "unlink \"" << fn << "\" failed";
}
}
static void DeleteStash(const std::string& base) {
if (base.empty()) return;
LOG(INFO) << "deleting stash " << base;
std::string dirname = GetStashFileName(base, "", "");
EnumerateStash(dirname, DeleteFile);
if (rmdir(dirname.c_str()) == -1) {
if (errno != ENOENT && errno != ENOTDIR) {
PLOG(ERROR) << "rmdir \"" << dirname << "\" failed";
}
}
}
static int LoadStash(const CommandParameters& params, const std::string& id, bool verify,
std::vector<uint8_t>* buffer, bool printnoent) {
// In verify mode, if source range_set was saved for the given hash, check contents in the source
// blocks first. If the check fails, search for the stashed files on /cache as usual.
if (!params.canwrite) {
if (stash_map.find(id) != stash_map.end()) {
const RangeSet& src = stash_map[id];
allocate(src.blocks() * BLOCKSIZE, buffer);
if (ReadBlocks(src, buffer, params.fd) == -1) {
LOG(ERROR) << "failed to read source blocks in stash map.";
return -1;
}
if (VerifyBlocks(id, *buffer, src.blocks(), true) != 0) {
LOG(ERROR) << "failed to verify loaded source blocks in stash map.";
if (!is_retry) {
PrintHashForCorruptedStashedBlocks(id, *buffer, src);
}
return -1;
}
return 0;
}
}
std::string fn = GetStashFileName(params.stashbase, id, "");
struct stat sb;
if (stat(fn.c_str(), &sb) == -1) {
if (errno != ENOENT || printnoent) {
PLOG(ERROR) << "stat \"" << fn << "\" failed";
PrintHashForMissingStashedBlocks(id, params.fd);
}
return -1;
}
LOG(INFO) << " loading " << fn;
if ((sb.st_size % BLOCKSIZE) != 0) {
LOG(ERROR) << fn << " size " << sb.st_size << " not multiple of block size " << BLOCKSIZE;
return -1;
}
android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(fn.c_str(), O_RDONLY)));
if (fd == -1) {
failure_type = errno == EIO ? kEioFailure : kFileOpenFailure;
PLOG(ERROR) << "open \"" << fn << "\" failed";
return -1;
}
allocate(sb.st_size, buffer);
if (!android::base::ReadFully(fd, buffer->data(), sb.st_size)) {
failure_type = errno == EIO ? kEioFailure : kFreadFailure;
PLOG(ERROR) << "Failed to read " << sb.st_size << " bytes of data";
return -1;
}
size_t blocks = sb.st_size / BLOCKSIZE;
if (verify && VerifyBlocks(id, *buffer, blocks, true) != 0) {
LOG(ERROR) << "unexpected contents in " << fn;
if (stash_map.find(id) == stash_map.end()) {
LOG(ERROR) << "failed to find source blocks number for stash " << id
<< " when executing command: " << params.cmdname;
} else {
const RangeSet& src = stash_map[id];
PrintHashForCorruptedStashedBlocks(id, *buffer, src);
}
DeleteFile(fn);
return -1;
}
return 0;
}
static int WriteStash(const std::string& base, const std::string& id, int blocks,
const std::vector<uint8_t>& buffer, bool checkspace, bool* exists) {
if (base.empty()) {
return -1;
}
if (checkspace && !CheckAndFreeSpaceOnCache(blocks * BLOCKSIZE)) {
LOG(ERROR) << "not enough space to write stash";
return -1;
}
std::string fn = GetStashFileName(base, id, ".partial");
std::string cn = GetStashFileName(base, id, "");
if (exists) {
struct stat sb;
int res = stat(cn.c_str(), &sb);
if (res == 0) {
// The file already exists and since the name is the hash of the contents,
// it's safe to assume the contents are identical (accidental hash collisions
// are unlikely)
LOG(INFO) << " skipping " << blocks << " existing blocks in " << cn;
*exists = true;
return 0;
}
*exists = false;
}
LOG(INFO) << " writing " << blocks << " blocks to " << cn;
android::base::unique_fd fd(
TEMP_FAILURE_RETRY(open(fn.c_str(), O_WRONLY | O_CREAT | O_TRUNC, STASH_FILE_MODE)));
if (fd == -1) {
failure_type = errno == EIO ? kEioFailure : kFileOpenFailure;
PLOG(ERROR) << "failed to create \"" << fn << "\"";
return -1;
}
if (fchown(fd, AID_SYSTEM, AID_SYSTEM) != 0) { // system user
PLOG(ERROR) << "failed to chown \"" << fn << "\"";
return -1;
}
if (!android::base::WriteFully(fd, buffer.data(), blocks * BLOCKSIZE)) {
failure_type = errno == EIO ? kEioFailure : kFwriteFailure;
PLOG(ERROR) << "Failed to write " << blocks * BLOCKSIZE << " bytes of data";
return -1;
}
if (fsync(fd) == -1) {
failure_type = errno == EIO ? kEioFailure : kFsyncFailure;
PLOG(ERROR) << "fsync \"" << fn << "\" failed";
return -1;
}
if (rename(fn.c_str(), cn.c_str()) == -1) {
PLOG(ERROR) << "rename(\"" << fn << "\", \"" << cn << "\") failed";
return -1;
}
std::string dname = GetStashFileName(base, "", "");
if (!FsyncDir(dname)) {
return -1;
}
return 0;
}
// Creates a directory for storing stash files and checks if the /cache partition
// hash enough space for the expected amount of blocks we need to store. Returns
// >0 if we created the directory, zero if it existed already, and <0 of failure.
static int CreateStash(State* state, size_t maxblocks, const std::string& base) {
std::string dirname = GetStashFileName(base, "", "");
struct stat sb;
int res = stat(dirname.c_str(), &sb);
if (res == -1 && errno != ENOENT) {
ErrorAbort(state, kStashCreationFailure, "stat \"%s\" failed: %s", dirname.c_str(),
strerror(errno));
return -1;
}
size_t max_stash_size = maxblocks * BLOCKSIZE;
if (res == -1) {
LOG(INFO) << "creating stash " << dirname;
res = mkdir_recursively(dirname, STASH_DIRECTORY_MODE, false, nullptr);
if (res != 0) {
ErrorAbort(state, kStashCreationFailure, "mkdir \"%s\" failed: %s", dirname.c_str(),
strerror(errno));
return -1;
}
if (chown(dirname.c_str(), AID_SYSTEM, AID_SYSTEM) != 0) { // system user
ErrorAbort(state, kStashCreationFailure, "chown \"%s\" failed: %s", dirname.c_str(),
strerror(errno));
return -1;
}
if (!CheckAndFreeSpaceOnCache(max_stash_size)) {
ErrorAbort(state, kStashCreationFailure, "not enough space for stash (%zu needed)",
max_stash_size);
return -1;
}
return 1; // Created directory
}
LOG(INFO) << "using existing stash " << dirname;
// If the directory already exists, calculate the space already allocated to stash files and check
// if there's enough for all required blocks. Delete any partially completed stash files first.
EnumerateStash(dirname, [](const std::string& fn) {
if (android::base::EndsWith(fn, ".partial")) {
DeleteFile(fn);
}
});
size_t existing = 0;
EnumerateStash(dirname, [&existing](const std::string& fn) {
if (fn.empty()) return;
struct stat sb;
if (stat(fn.c_str(), &sb) == -1) {
PLOG(ERROR) << "stat \"" << fn << "\" failed";
return;
}
existing += static_cast<size_t>(sb.st_size);
});
if (max_stash_size > existing) {
size_t needed = max_stash_size - existing;
if (!CheckAndFreeSpaceOnCache(needed)) {
ErrorAbort(state, kStashCreationFailure, "not enough space for stash (%zu more needed)",
needed);
return -1;
}
}
return 0; // Using existing directory
}
static int FreeStash(const std::string& base, const std::string& id) {
if (base.empty() || id.empty()) {
return -1;
}
DeleteFile(GetStashFileName(base, id, ""));
return 0;
}
// Source contains packed data, which we want to move to the locations given in locs in the dest
// buffer. source and dest may be the same buffer.
static void MoveRange(std::vector<uint8_t>& dest, const RangeSet& locs,
const std::vector<uint8_t>& source) {
const uint8_t* from = source.data();
uint8_t* to = dest.data();
size_t start = locs.blocks();
// Must do the movement backward.
for (auto it = locs.crbegin(); it != locs.crend(); it++) {
size_t blocks = it->second - it->first;
start -= blocks;
memmove(to + (it->first * BLOCKSIZE), from + (start * BLOCKSIZE), blocks * BLOCKSIZE);
}
}
/**
* We expect to parse the remainder of the parameter tokens as one of:
*
* <src_block_count> <src_range>
* (loads data from source image only)
*
* <src_block_count> - <[stash_id:stash_range] ...>
* (loads data from stashes only)
*
* <src_block_count> <src_range> <src_loc> <[stash_id:stash_range] ...>
* (loads data from both source image and stashes)
*
* On return, params.buffer is filled with the loaded source data (rearranged and combined with
* stashed data as necessary). buffer may be reallocated if needed to accommodate the source data.
* tgt is the target RangeSet for detecting overlaps. Any stashes required are loaded using
* LoadStash.
*/
static int LoadSourceBlocks(CommandParameters& params, const RangeSet& tgt, size_t* src_blocks,
bool* overlap) {
CHECK(src_blocks != nullptr);
CHECK(overlap != nullptr);
// <src_block_count>
const std::string& token = params.tokens[params.cpos++];
if (!android::base::ParseUint(token, src_blocks)) {
LOG(ERROR) << "invalid src_block_count \"" << token << "\"";
return -1;
}
allocate(*src_blocks * BLOCKSIZE, &params.buffer);
// "-" or <src_range> [<src_loc>]
if (params.tokens[params.cpos] == "-") {
// no source ranges, only stashes
params.cpos++;
} else {
RangeSet src = RangeSet::Parse(params.tokens[params.cpos++]);
CHECK(static_cast<bool>(src));
*overlap = src.Overlaps(tgt);
if (ReadBlocks(src, &params.buffer, params.fd) == -1) {
return -1;
}
if (params.cpos >= params.tokens.size()) {
// no stashes, only source range
return 0;
}
RangeSet locs = RangeSet::Parse(params.tokens[params.cpos++]);
CHECK(static_cast<bool>(locs));
MoveRange(params.buffer, locs, params.buffer);
}
// <[stash_id:stash_range]>
while (params.cpos < params.tokens.size()) {
// Each word is a an index into the stash table, a colon, and then a RangeSet describing where
// in the source block that stashed data should go.
std::vector<std::string> tokens = android::base::Split(params.tokens[params.cpos++], ":");
if (tokens.size() != 2) {
LOG(ERROR) << "invalid parameter";
return -1;
}
std::vector<uint8_t> stash;
if (LoadStash(params, tokens[0], false, &stash, true) == -1) {
// These source blocks will fail verification if used later, but we
// will let the caller decide if this is a fatal failure
LOG(ERROR) << "failed to load stash " << tokens[0];
continue;
}
RangeSet locs = RangeSet::Parse(tokens[1]);
CHECK(static_cast<bool>(locs));
MoveRange(params.buffer, locs, stash);
}
return 0;
}
/**
* Do a source/target load for move/bsdiff/imgdiff in version 3.
*
* We expect to parse the remainder of the parameter tokens as one of:
*
* <tgt_range> <src_block_count> <src_range>
* (loads data from source image only)
*
* <tgt_range> <src_block_count> - <[stash_id:stash_range] ...>
* (loads data from stashes only)
*
* <tgt_range> <src_block_count> <src_range> <src_loc> <[stash_id:stash_range] ...>
* (loads data from both source image and stashes)
*
* 'onehash' tells whether to expect separate source and targe block hashes, or if they are both the
* same and only one hash should be expected. params.isunresumable will be set to true if block
* verification fails in a way that the update cannot be resumed anymore.
*
* If the function is unable to load the necessary blocks or their contents don't match the hashes,
* the return value is -1 and the command should be aborted.
*
* If the return value is 1, the command has already been completed according to the contents of the
* target blocks, and should not be performed again.
*
* If the return value is 0, source blocks have expected content and the command can be performed.
*/
static int LoadSrcTgtVersion3(CommandParameters& params, RangeSet* tgt, size_t* src_blocks,
bool onehash) {
CHECK(src_blocks != nullptr);
if (params.cpos >= params.tokens.size()) {
LOG(ERROR) << "missing source hash";
return -1;
}
std::string srchash = params.tokens[params.cpos++];
std::string tgthash;
if (onehash) {
tgthash = srchash;
} else {
if (params.cpos >= params.tokens.size()) {
LOG(ERROR) << "missing target hash";
return -1;
}
tgthash = params.tokens[params.cpos++];
}
// At least it needs to provide three parameters: <tgt_range>, <src_block_count> and
// "-"/<src_range>.
if (params.cpos + 2 >= params.tokens.size()) {
LOG(ERROR) << "invalid parameters";
return -1;
}
// <tgt_range>
*tgt = RangeSet::Parse(params.tokens[params.cpos++]);
CHECK(static_cast<bool>(*tgt));
std::vector<uint8_t> tgtbuffer(tgt->blocks() * BLOCKSIZE);
if (ReadBlocks(*tgt, &tgtbuffer, params.fd) == -1) {
return -1;
}
// Return now if target blocks already have expected content.
if (VerifyBlocks(tgthash, tgtbuffer, tgt->blocks(), false) == 0) {
return 1;
}
// Load source blocks.
bool overlap = false;
if (LoadSourceBlocks(params, *tgt, src_blocks, &overlap) == -1) {
return -1;
}
if (VerifyBlocks(srchash, params.buffer, *src_blocks, true) == 0) {
// If source and target blocks overlap, stash the source blocks so we can resume from possible
// write errors. In verify mode, we can skip stashing because the source blocks won't be
// overwritten.
if (overlap && params.canwrite) {
LOG(INFO) << "stashing " << *src_blocks << " overlapping blocks to " << srchash;
bool stash_exists = false;
if (WriteStash(params.stashbase, srchash, *src_blocks, params.buffer, true,
&stash_exists) != 0) {
LOG(ERROR) << "failed to stash overlapping source blocks";
return -1;
}
params.stashed += *src_blocks;
// Can be deleted when the write has completed.
if (!stash_exists) {
params.freestash = srchash;
}
}
// Source blocks have expected content, command can proceed.
return 0;
}
if (overlap && LoadStash(params, srchash, true, &params.buffer, true) == 0) {
// Overlapping source blocks were previously stashed, command can proceed. We are recovering
// from an interrupted command, so we don't know if the stash can safely be deleted after this
// command.
return 0;
}
// Valid source data not available, update cannot be resumed.
LOG(ERROR) << "partition has unexpected contents";
PrintHashForCorruptedSourceBlocks(params, params.buffer);
params.isunresumable = true;
return -1;
}
static int PerformCommandMove(CommandParameters& params) {
size_t blocks = 0;
RangeSet tgt;
int status = LoadSrcTgtVersion3(params, &tgt, &blocks, true);
if (status == -1) {
LOG(ERROR) << "failed to read blocks for move";
return -1;
}
if (status == 0) {
params.foundwrites = true;
} else {
params.target_verified = true;
if (params.foundwrites) {
LOG(WARNING) << "warning: commands executed out of order [" << params.cmdname << "]";
}
}
if (params.canwrite) {
if (status == 0) {
LOG(INFO) << " moving " << blocks << " blocks";
if (WriteBlocks(tgt, params.buffer, params.fd) == -1) {
return -1;
}
} else {
LOG(INFO) << "skipping " << blocks << " already moved blocks";
}
}
if (!params.freestash.empty()) {
FreeStash(params.stashbase, params.freestash);
params.freestash.clear();
}
params.written += tgt.blocks();
return 0;
}
static int PerformCommandStash(CommandParameters& params) {
// <stash_id> <src_range>
if (params.cpos + 1 >= params.tokens.size()) {
LOG(ERROR) << "missing id and/or src range fields in stash command";
return -1;
}
const std::string& id = params.tokens[params.cpos++];
if (LoadStash(params, id, true, &params.buffer, false) == 0) {
// Stash file already exists and has expected contents. Do not read from source again, as the
// source may have been already overwritten during a previous attempt.
return 0;
}
RangeSet src = RangeSet::Parse(params.tokens[params.cpos++]);
CHECK(static_cast<bool>(src));
size_t blocks = src.blocks();
allocate(blocks * BLOCKSIZE, &params.buffer);
if (ReadBlocks(src, &params.buffer, params.fd) == -1) {
return -1;
}
stash_map[id] = src;
if (VerifyBlocks(id, params.buffer, blocks, true) != 0) {
// Source blocks have unexpected contents. If we actually need this data later, this is an
// unrecoverable error. However, the command that uses the data may have already completed
// previously, so the possible failure will occur during source block verification.
LOG(ERROR) << "failed to load source blocks for stash " << id;
return 0;
}
// In verify mode, we don't need to stash any blocks.
if (!params.canwrite) {
return 0;
}
LOG(INFO) << "stashing " << blocks << " blocks to " << id;
int result = WriteStash(params.stashbase, id, blocks, params.buffer, false, nullptr);
if (result == 0) {
params.stashed += blocks;
}
return result;
}
static int PerformCommandFree(CommandParameters& params) {
// <stash_id>
if (params.cpos >= params.tokens.size()) {
LOG(ERROR) << "missing stash id in free command";
return -1;
}
const std::string& id = params.tokens[params.cpos++];
stash_map.erase(id);
if (params.createdstash || params.canwrite) {
return FreeStash(params.stashbase, id);
}
return 0;
}
static int PerformCommandZero(CommandParameters& params) {
if (params.cpos >= params.tokens.size()) {
LOG(ERROR) << "missing target blocks for zero";
return -1;
}
RangeSet tgt = RangeSet::Parse(params.tokens[params.cpos++]);
CHECK(static_cast<bool>(tgt));
LOG(INFO) << " zeroing " << tgt.blocks() << " blocks";
allocate(BLOCKSIZE, &params.buffer);
memset(params.buffer.data(), 0, BLOCKSIZE);
if (params.canwrite) {
for (const auto& [begin, end] : tgt) {
off64_t offset = static_cast<off64_t>(begin) * BLOCKSIZE;
size_t size = (end - begin) * BLOCKSIZE;
if (!discard_blocks(params.fd, offset, size)) {
return -1;
}
if (!check_lseek(params.fd, offset, SEEK_SET)) {
return -1;
}
for (size_t j = begin; j < end; ++j) {
if (!android::base::WriteFully(params.fd, params.buffer.data(), BLOCKSIZE)) {
failure_type = errno == EIO ? kEioFailure : kFwriteFailure;
PLOG(ERROR) << "Failed to write " << BLOCKSIZE << " bytes of data";
return -1;
}
}
}
}
if (params.cmdname[0] == 'z') {
// Update only for the zero command, as the erase command will call
// this if DEBUG_ERASE is defined.
params.written += tgt.blocks();
}
return 0;
}
static int PerformCommandNew(CommandParameters& params) {
if (params.cpos >= params.tokens.size()) {
LOG(ERROR) << "missing target blocks for new";
return -1;
}
RangeSet tgt = RangeSet::Parse(params.tokens[params.cpos++]);
CHECK(static_cast<bool>(tgt));
if (params.canwrite) {
LOG(INFO) << " writing " << tgt.blocks() << " blocks of new data";
pthread_mutex_lock(&params.nti.mu);
params.nti.writer = std::make_unique<RangeSinkWriter>(params.fd, tgt);
pthread_cond_broadcast(&params.nti.cv);
while (params.nti.writer != nullptr) {
if (!params.nti.receiver_available) {
LOG(ERROR) << "missing " << (tgt.blocks() * BLOCKSIZE - params.nti.writer->BytesWritten())
<< " bytes of new data";
pthread_mutex_unlock(&params.nti.mu);
return -1;
}
pthread_cond_wait(&params.nti.cv, &params.nti.mu);
}
pthread_mutex_unlock(&params.nti.mu);
}
params.written += tgt.blocks();
return 0;
}
static int PerformCommandDiff(CommandParameters& params) {
// <offset> <length>
if (params.cpos + 1 >= params.tokens.size()) {
LOG(ERROR) << "missing patch offset or length for " << params.cmdname;
return -1;
}
size_t offset;
if (!android::base::ParseUint(params.tokens[params.cpos++], &offset)) {
LOG(ERROR) << "invalid patch offset";
return -1;
}
size_t len;
if (!android::base::ParseUint(params.tokens[params.cpos++], &len)) {
LOG(ERROR) << "invalid patch len";
return -1;
}
RangeSet tgt;
size_t blocks = 0;
int status = LoadSrcTgtVersion3(params, &tgt, &blocks, false);
if (status == -1) {
LOG(ERROR) << "failed to read blocks for diff";
return -1;
}
if (status == 0) {
params.foundwrites = true;
} else {
params.target_verified = true;
if (params.foundwrites) {
LOG(WARNING) << "warning: commands executed out of order [" << params.cmdname << "]";
}
}
if (params.canwrite) {
if (status == 0) {
LOG(INFO) << "patching " << blocks << " blocks to " << tgt.blocks();
Value patch_value(
Value::Type::BLOB,
std::string(reinterpret_cast<const char*>(params.patch_start + offset), len));
RangeSinkWriter writer(params.fd, tgt);
if (params.cmdname[0] == 'i') { // imgdiff
if (ApplyImagePatch(params.buffer.data(), blocks * BLOCKSIZE, patch_value,
std::bind(&RangeSinkWriter::Write, &writer, std::placeholders::_1,
std::placeholders::_2),
nullptr) != 0) {
LOG(ERROR) << "Failed to apply image patch.";
failure_type = kPatchApplicationFailure;
return -1;
}
} else {
if (ApplyBSDiffPatch(params.buffer.data(), blocks * BLOCKSIZE, patch_value, 0,
std::bind(&RangeSinkWriter::Write, &writer, std::placeholders::_1,
std::placeholders::_2)) != 0) {
LOG(ERROR) << "Failed to apply bsdiff patch.";
failure_type = kPatchApplicationFailure;
return -1;
}
}
// We expect the output of the patcher to fill the tgt ranges exactly.
if (!writer.Finished()) {
LOG(ERROR) << "Failed to fully write target blocks (range sink underrun): Missing "
<< writer.AvailableSpace() << " bytes";
failure_type = kPatchApplicationFailure;
return -1;
}
} else {
LOG(INFO) << "skipping " << blocks << " blocks already patched to " << tgt.blocks() << " ["
<< params.cmdline << "]";
}
}
if (!params.freestash.empty()) {
FreeStash(params.stashbase, params.freestash);
params.freestash.clear();
}
params.written += tgt.blocks();
return 0;
}
static int PerformCommandErase(CommandParameters& params) {
if (DEBUG_ERASE) {
return PerformCommandZero(params);
}
struct stat sb;
if (fstat(params.fd, &sb) == -1) {
PLOG(ERROR) << "failed to fstat device to erase";
return -1;
}
if (!S_ISBLK(sb.st_mode)) {
LOG(ERROR) << "not a block device; skipping erase";
return -1;
}
if (params.cpos >= params.tokens.size()) {
LOG(ERROR) << "missing target blocks for erase";
return -1;
}
RangeSet tgt = RangeSet::Parse(params.tokens[params.cpos++]);
CHECK(static_cast<bool>(tgt));
if (params.canwrite) {
LOG(INFO) << " erasing " << tgt.blocks() << " blocks";
for (const auto& [begin, end] : tgt) {
off64_t offset = static_cast<off64_t>(begin) * BLOCKSIZE;
size_t size = (end - begin) * BLOCKSIZE;
if (!discard_blocks(params.fd, offset, size, true /* force */)) {
return -1;
}
}
}
return 0;
}
static int PerformCommandAbort(CommandParameters&) {
LOG(INFO) << "Aborting as instructed";
return -1;
}
// Computes the hash_tree bytes based on the parameters, checks if the root hash of the tree
// matches the expected hash and writes the result to the specified range on the block_device.
// Hash_tree computation arguments:
// hash_tree_ranges
// source_ranges
// hash_algorithm
// salt_hex
// root_hash
static int PerformCommandComputeHashTree(CommandParameters& params) {
if (params.cpos + 5 != params.tokens.size()) {
LOG(ERROR) << "Invaild arguments count in hash computation " << params.cmdline;
return -1;
}
// Expects the hash_tree data to be contiguous.
RangeSet hash_tree_ranges = RangeSet::Parse(params.tokens[params.cpos++]);
if (!hash_tree_ranges || hash_tree_ranges.size() != 1) {
LOG(ERROR) << "Invalid hash tree ranges in " << params.cmdline;
return -1;
}
RangeSet source_ranges = RangeSet::Parse(params.tokens[params.cpos++]);
if (!source_ranges) {
LOG(ERROR) << "Invalid source ranges in " << params.cmdline;
return -1;
}
auto hash_function = HashTreeBuilder::HashFunction(params.tokens[params.cpos++]);
if (hash_function == nullptr) {
LOG(ERROR) << "Invalid hash algorithm in " << params.cmdline;
return -1;
}
std::vector<unsigned char> salt;
std::string salt_hex = params.tokens[params.cpos++];
if (salt_hex.empty() || !HashTreeBuilder::ParseBytesArrayFromString(salt_hex, &salt)) {
LOG(ERROR) << "Failed to parse salt in " << params.cmdline;
return -1;
}
std::string expected_root_hash = params.tokens[params.cpos++];
if (expected_root_hash.empty()) {
LOG(ERROR) << "Invalid root hash in " << params.cmdline;
return -1;
}
// Starts the hash_tree computation.
HashTreeBuilder builder(BLOCKSIZE, hash_function);
if (!builder.Initialize(static_cast<int64_t>(source_ranges.blocks()) * BLOCKSIZE, salt)) {
LOG(ERROR) << "Failed to initialize hash tree computation, source " << source_ranges.ToString()
<< ", salt " << salt_hex;
return -1;
}
// Iterates through every block in the source_ranges and updates the hash tree structure
// accordingly.
for (const auto& [begin, end] : source_ranges) {
uint8_t buffer[BLOCKSIZE];
if (!check_lseek(params.fd, static_cast<off64_t>(begin) * BLOCKSIZE, SEEK_SET)) {
PLOG(ERROR) << "Failed to seek to block: " << begin;
return -1;
}
for (size_t i = begin; i < end; i++) {
if (!android::base::ReadFully(params.fd, buffer, BLOCKSIZE)) {
failure_type = errno == EIO ? kEioFailure : kFreadFailure;
LOG(ERROR) << "Failed to read data in " << begin << ":" << end;
return -1;
}
if (!builder.Update(reinterpret_cast<unsigned char*>(buffer), BLOCKSIZE)) {
LOG(ERROR) << "Failed to update hash tree builder";
return -1;
}
}
}
if (!builder.BuildHashTree()) {
LOG(ERROR) << "Failed to build hash tree";
return -1;
}
std::string root_hash_hex = HashTreeBuilder::BytesArrayToString(builder.root_hash());
if (root_hash_hex != expected_root_hash) {
LOG(ERROR) << "Root hash of the verity hash tree doesn't match the expected value. Expected: "
<< expected_root_hash << ", actual: " << root_hash_hex;
return -1;
}
uint64_t write_offset = static_cast<uint64_t>(hash_tree_ranges.GetBlockNumber(0)) * BLOCKSIZE;
if (params.canwrite && !builder.WriteHashTreeToFd(params.fd, write_offset)) {
LOG(ERROR) << "Failed to write hash tree to output";
return -1;
}
// TODO(xunchang) validates the written bytes
return 0;
}
using CommandFunction = std::function<int(CommandParameters&)>;
using CommandMap = std::unordered_map<Command::Type, CommandFunction>;
static bool Sha1DevicePath(const std::string& path, uint8_t digest[SHA_DIGEST_LENGTH]) {
auto device_name = android::base::Basename(path);
auto dm_target_name_path = "/sys/block/" + device_name + "/dm/name";
struct stat sb;
if (stat(dm_target_name_path.c_str(), &sb) == 0) {
// This is a device mapper target. Use partition name as part of the hash instead. Do not
// include extents as part of the hash, because the size of a partition may be shrunk after
// the patches are applied.
std::string dm_target_name;
if (!android::base::ReadFileToString(dm_target_name_path, &dm_target_name)) {
PLOG(ERROR) << "Cannot read " << dm_target_name_path;
return false;
}
SHA1(reinterpret_cast<const uint8_t*>(dm_target_name.data()), dm_target_name.size(), digest);
return true;
}
if (errno != ENOENT) {
// This is a device mapper target, but its name cannot be retrieved.
PLOG(ERROR) << "Cannot get dm target name for " << path;
return false;
}
// This doesn't appear to be a device mapper target, but if its name starts with dm-, something
// else might have gone wrong.
if (android::base::StartsWith(device_name, "dm-")) {
LOG(WARNING) << "Device " << path << " starts with dm- but is not mapped by device-mapper.";
}
// Stash directory should be different for each partition to avoid conflicts when updating
// multiple partitions at the same time, so we use the hash of the block device name as the base
// directory.
SHA1(reinterpret_cast<const uint8_t*>(path.data()), path.size(), digest);
return true;
}
static Value* PerformBlockImageUpdate(const char* name, State* state,
const std::vector<std::unique_ptr<Expr>>& argv,
const CommandMap& command_map, bool dryrun) {
CommandParameters params = {};
stash_map.clear();
params.canwrite = !dryrun;
LOG(INFO) << "performing " << (dryrun ? "verification" : "update");
if (state->is_retry) {
is_retry = true;
LOG(INFO) << "This update is a retry.";
}
if (argv.size() != 4) {
ErrorAbort(state, kArgsParsingFailure, "block_image_update expects 4 arguments, got %zu",
argv.size());
return StringValue("");
}
std::vector<std::unique_ptr<Value>> args;
if (!ReadValueArgs(state, argv, &args)) {
return nullptr;
}
// args:
// - block device (or file) to modify in-place
// - transfer list (blob)
// - new data stream (filename within package.zip)
// - patch stream (filename within package.zip, must be uncompressed)
const std::unique_ptr<Value>& blockdev_filename = args[0];
const std::unique_ptr<Value>& transfer_list_value = args[1];
const std::unique_ptr<Value>& new_data_fn = args[2];
const std::unique_ptr<Value>& patch_data_fn = args[3];
if (blockdev_filename->type != Value::Type::STRING) {
ErrorAbort(state, kArgsParsingFailure, "blockdev_filename argument to %s must be string", name);
return StringValue("");
}
if (transfer_list_value->type != Value::Type::BLOB) {
ErrorAbort(state, kArgsParsingFailure, "transfer_list argument to %s must be blob", name);
return StringValue("");
}
if (new_data_fn->type != Value::Type::STRING) {
ErrorAbort(state, kArgsParsingFailure, "new_data_fn argument to %s must be string", name);
return StringValue("");
}
if (patch_data_fn->type != Value::Type::STRING) {
ErrorAbort(state, kArgsParsingFailure, "patch_data_fn argument to %s must be string", name);
return StringValue("");
}
UpdaterInfo* ui = static_cast<UpdaterInfo*>(state->cookie);
if (ui == nullptr) {
return StringValue("");
}
FILE* cmd_pipe = ui->cmd_pipe;
ZipArchiveHandle za = ui->package_zip;
if (cmd_pipe == nullptr || za == nullptr) {
return StringValue("");
}
ZipString path_data(patch_data_fn->data.c_str());
ZipEntry patch_entry;
if (FindEntry(za, path_data, &patch_entry) != 0) {
LOG(ERROR) << name << "(): no file \"" << patch_data_fn->data << "\" in package";
return StringValue("");
}
params.patch_start = ui->package_zip_addr + patch_entry.offset;
ZipString new_data(new_data_fn->data.c_str());
ZipEntry new_entry;
if (FindEntry(za, new_data, &new_entry) != 0) {
LOG(ERROR) << name << "(): no file \"" << new_data_fn->data << "\" in package";
return StringValue("");
}
params.fd.reset(TEMP_FAILURE_RETRY(open(blockdev_filename->data.c_str(), O_RDWR)));
if (params.fd == -1) {
failure_type = errno == EIO ? kEioFailure : kFileOpenFailure;
PLOG(ERROR) << "open \"" << blockdev_filename->data << "\" failed";
return StringValue("");
}
uint8_t digest[SHA_DIGEST_LENGTH];
if (!Sha1DevicePath(blockdev_filename->data, digest)) {
return StringValue("");
}
params.stashbase = print_sha1(digest);
// Possibly do return early on retry, by checking the marker. If the update on this partition has
// been finished (but interrupted at a later point), there could be leftover on /cache that would
// fail the no-op retry.
std::string updated_marker = GetStashFileName(params.stashbase + ".UPDATED", "", "");
if (is_retry) {
struct stat sb;
int result = stat(updated_marker.c_str(), &sb);
if (result == 0) {
LOG(INFO) << "Skipping already updated partition " << blockdev_filename->data
<< " based on marker";
return StringValue("t");
}
} else {
// Delete the obsolete marker if any.
std::string err;
if (!android::base::RemoveFileIfExists(updated_marker, &err)) {
LOG(ERROR) << "Failed to remove partition updated marker " << updated_marker << ": " << err;
return StringValue("");
}
}
static constexpr size_t kTransferListHeaderLines = 4;
std::vector<std::string> lines = android::base::Split(transfer_list_value->data, "\n");
if (lines.size() < kTransferListHeaderLines) {
ErrorAbort(state, kArgsParsingFailure, "too few lines in the transfer list [%zu]",
lines.size());
return StringValue("");
}
// First line in transfer list is the version number.
if (!android::base::ParseInt(lines[0], &params.version, 3, 4)) {
LOG(ERROR) << "unexpected transfer list version [" << lines[0] << "]";
return StringValue("");
}
LOG(INFO) << "blockimg version is " << params.version;
// Second line in transfer list is the total number of blocks we expect to write.
size_t total_blocks;
if (!android::base::ParseUint(lines[1], &total_blocks)) {
ErrorAbort(state, kArgsParsingFailure, "unexpected block count [%s]", lines[1].c_str());
return StringValue("");
}
if (total_blocks == 0) {
return StringValue("t");
}
// Third line is how many stash entries are needed simultaneously.
LOG(INFO) << "maximum stash entries " << lines[2];
// Fourth line is the maximum number of blocks that will be stashed simultaneously
size_t stash_max_blocks;
if (!android::base::ParseUint(lines[3], &stash_max_blocks)) {
ErrorAbort(state, kArgsParsingFailure, "unexpected maximum stash blocks [%s]",
lines[3].c_str());
return StringValue("");
}
int res = CreateStash(state, stash_max_blocks, params.stashbase);
if (res == -1) {
return StringValue("");
}
params.createdstash = res;
// Set up the new data writer.
if (params.canwrite) {
params.nti.za = za;
params.nti.entry = new_entry;
params.nti.brotli_compressed = android::base::EndsWith(new_data_fn->data, ".br");
if (params.nti.brotli_compressed) {
// Initialize brotli decoder state.
params.nti.brotli_decoder_state = BrotliDecoderCreateInstance(nullptr, nullptr, nullptr);
}
params.nti.receiver_available = true;
pthread_mutex_init(&params.nti.mu, nullptr);
pthread_cond_init(&params.nti.cv, nullptr);
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
int error = pthread_create(&params.thread, &attr, unzip_new_data, &params.nti);
if (error != 0) {
LOG(ERROR) << "pthread_create failed: " << strerror(error);
return StringValue("");
}
}
// When performing an update, save the index and cmdline of the current command into the
// last_command_file.
// Upon resuming an update, read the saved index first; then
// 1. In verification mode, check if the 'move' or 'diff' commands before the saved index has
// the expected target blocks already. If not, these commands cannot be skipped and we need
// to attempt to execute them again. Therefore, we will delete the last_command_file so that
// the update will resume from the start of the transfer list.
// 2. In update mode, skip all commands before the saved index. Therefore, we can avoid deleting
// stashes with duplicate id unintentionally (b/69858743); and also speed up the update.
// If an update succeeds or is unresumable, delete the last_command_file.
bool skip_executed_command = true;
size_t saved_last_command_index;
if (!ParseLastCommandFile(&saved_last_command_index)) {
DeleteLastCommandFile();
// We failed to parse the last command. Disallow skipping executed commands.
skip_executed_command = false;
}
int rc = -1;
// Subsequent lines are all individual transfer commands
for (size_t i = kTransferListHeaderLines; i < lines.size(); i++) {
const std::string& line = lines[i];
if (line.empty()) continue;
size_t cmdindex = i - kTransferListHeaderLines;
params.tokens = android::base::Split(line, " ");
params.cpos = 0;
params.cmdname = params.tokens[params.cpos++];
params.cmdline = line;
params.target_verified = false;
Command::Type cmd_type = Command::ParseType(params.cmdname);
if (cmd_type == Command::Type::LAST) {
LOG(ERROR) << "unexpected command [" << params.cmdname << "]";
goto pbiudone;
}
const CommandFunction& performer = command_map.at(cmd_type);
// Skip the command if we explicitly set the corresponding function pointer to nullptr, e.g.
// "erase" during block_image_verify.
if (performer == nullptr) {
LOG(DEBUG) << "skip executing command [" << line << "]";
continue;
}
// Skip all commands before the saved last command index when resuming an update, except for
// "new" command. Because new commands read in the data sequentially.
if (params.canwrite && skip_executed_command && cmdindex <= saved_last_command_index &&
cmd_type != Command::Type::NEW) {
LOG(INFO) << "Skipping already executed command: " << cmdindex
<< ", last executed command for previous update: " << saved_last_command_index;
continue;
}
if (performer(params) == -1) {
LOG(ERROR) << "failed to execute command [" << line << "]";
if (cmd_type == Command::Type::COMPUTE_HASH_TREE && failure_type == kNoCause) {
failure_type = kHashTreeComputationFailure;
}
goto pbiudone;
}
// In verify mode, check if the commands before the saved last_command_index have been executed
// correctly. If some target blocks have unexpected contents, delete the last command file so
// that we will resume the update from the first command in the transfer list.
if (!params.canwrite && skip_executed_command && cmdindex <= saved_last_command_index) {
// TODO(xunchang) check that the cmdline of the saved index is correct.
if ((cmd_type == Command::Type::MOVE || cmd_type == Command::Type::BSDIFF ||
cmd_type == Command::Type::IMGDIFF) &&
!params.target_verified) {
LOG(WARNING) << "Previously executed command " << saved_last_command_index << ": "
<< params.cmdline << " doesn't produce expected target blocks.";
skip_executed_command = false;
DeleteLastCommandFile();
}
}
if (params.canwrite) {
if (fsync(params.fd) == -1) {
failure_type = errno == EIO ? kEioFailure : kFsyncFailure;
PLOG(ERROR) << "fsync failed";
goto pbiudone;
}
if (!UpdateLastCommandIndex(cmdindex, params.cmdline)) {
LOG(WARNING) << "Failed to update the last command file.";
}
fprintf(cmd_pipe, "set_progress %.4f\n", static_cast<double>(params.written) / total_blocks);
fflush(cmd_pipe);
}
}
rc = 0;
pbiudone:
if (params.canwrite) {
pthread_mutex_lock(&params.nti.mu);
if (params.nti.receiver_available) {
LOG(WARNING) << "new data receiver is still available after executing all commands.";
}
params.nti.receiver_available = false;
pthread_cond_broadcast(&params.nti.cv);
pthread_mutex_unlock(&params.nti.mu);
int ret = pthread_join(params.thread, nullptr);
if (ret != 0) {
LOG(WARNING) << "pthread join returned with " << strerror(ret);
}
if (rc == 0) {
LOG(INFO) << "wrote " << params.written << " blocks; expected " << total_blocks;
LOG(INFO) << "stashed " << params.stashed << " blocks";
LOG(INFO) << "max alloc needed was " << params.buffer.size();
const char* partition = strrchr(blockdev_filename->data.c_str(), '/');
if (partition != nullptr && *(partition + 1) != 0) {
fprintf(cmd_pipe, "log bytes_written_%s: %" PRIu64 "\n", partition + 1,
static_cast<uint64_t>(params.written) * BLOCKSIZE);
fprintf(cmd_pipe, "log bytes_stashed_%s: %" PRIu64 "\n", partition + 1,
static_cast<uint64_t>(params.stashed) * BLOCKSIZE);
fflush(cmd_pipe);
}
// Delete stash only after successfully completing the update, as it may contain blocks needed
// to complete the update later.
DeleteStash(params.stashbase);
DeleteLastCommandFile();
// Create a marker on /cache partition, which allows skipping the update on this partition on
// retry. The marker will be removed once booting into normal boot, or before starting next
// fresh install.
if (!SetUpdatedMarker(updated_marker)) {
LOG(WARNING) << "Failed to set updated marker; continuing";
}
}
pthread_mutex_destroy(&params.nti.mu);
pthread_cond_destroy(&params.nti.cv);
} else if (rc == 0) {
LOG(INFO) << "verified partition contents; update may be resumed";
}
if (fsync(params.fd) == -1) {
failure_type = errno == EIO ? kEioFailure : kFsyncFailure;
PLOG(ERROR) << "fsync failed";
}
// params.fd will be automatically closed because it's a unique_fd.
if (params.nti.brotli_decoder_state != nullptr) {
BrotliDecoderDestroyInstance(params.nti.brotli_decoder_state);
}
// Delete the last command file if the update cannot be resumed.
if (params.isunresumable) {
DeleteLastCommandFile();
}
// Only delete the stash if the update cannot be resumed, or it's a verification run and we
// created the stash.
if (params.isunresumable || (!params.canwrite && params.createdstash)) {
DeleteStash(params.stashbase);
}
if (failure_type != kNoCause && state->cause_code == kNoCause) {
state->cause_code = failure_type;
}
return StringValue(rc == 0 ? "t" : "");
}
/**
* The transfer list is a text file containing commands to transfer data from one place to another
* on the target partition. We parse it and execute the commands in order:
*
* zero [rangeset]
* - Fill the indicated blocks with zeros.
*
* new [rangeset]
* - Fill the blocks with data read from the new_data file.
*
* erase [rangeset]
* - Mark the given blocks as empty.
*
* move <...>
* bsdiff <patchstart> <patchlen> <...>
* imgdiff <patchstart> <patchlen> <...>
* - Read the source blocks, apply a patch (or not in the case of move), write result to target
* blocks. bsdiff or imgdiff specifies the type of patch; move means no patch at all.
*
* See the comments in LoadSrcTgtVersion3() for a description of the <...> format.
*
* stash <stash_id> <src_range>
* - Load the given source range and stash the data in the given slot of the stash table.
*
* free <stash_id>
* - Free the given stash data.
*
* The creator of the transfer list will guarantee that no block is read (ie, used as the source for
* a patch or move) after it has been written.
*
* The creator will guarantee that a given stash is loaded (with a stash command) before it's used
* in a move/bsdiff/imgdiff command.
*
* Within one command the source and target ranges may overlap so in general we need to read the
* entire source into memory before writing anything to the target blocks.
*
* All the patch data is concatenated into one patch_data file in the update package. It must be
* stored uncompressed because we memory-map it in directly from the archive. (Since patches are
* already compressed, we lose very little by not compressing their concatenation.)
*
* Commands that read data from the partition (i.e. move/bsdiff/imgdiff/stash) have one or more
* additional hashes before the range parameters, which are used to check if the command has already
* been completed and verify the integrity of the source data.
*/
Value* BlockImageVerifyFn(const char* name, State* state,
const std::vector<std::unique_ptr<Expr>>& argv) {
// Commands which are not allowed are set to nullptr to skip them completely.
const CommandMap command_map{
// clang-format off
{ Command::Type::ABORT, PerformCommandAbort },
{ Command::Type::BSDIFF, PerformCommandDiff },
{ Command::Type::COMPUTE_HASH_TREE, PerformCommandComputeHashTree },
{ Command::Type::ERASE, nullptr },
{ Command::Type::FREE, PerformCommandFree },
{ Command::Type::IMGDIFF, PerformCommandDiff },
{ Command::Type::MOVE, PerformCommandMove },
{ Command::Type::NEW, nullptr },
{ Command::Type::STASH, PerformCommandStash },
{ Command::Type::ZERO, nullptr },
// clang-format on
};
CHECK_EQ(static_cast<size_t>(Command::Type::LAST), command_map.size());
// Perform a dry run without writing to test if an update can proceed.
return PerformBlockImageUpdate(name, state, argv, command_map, true);
}
Value* BlockImageUpdateFn(const char* name, State* state,
const std::vector<std::unique_ptr<Expr>>& argv) {
const CommandMap command_map{
// clang-format off
{ Command::Type::ABORT, PerformCommandAbort },
{ Command::Type::BSDIFF, PerformCommandDiff },
{ Command::Type::COMPUTE_HASH_TREE, PerformCommandComputeHashTree },
{ Command::Type::ERASE, PerformCommandErase },
{ Command::Type::FREE, PerformCommandFree },
{ Command::Type::IMGDIFF, PerformCommandDiff },
{ Command::Type::MOVE, PerformCommandMove },
{ Command::Type::NEW, PerformCommandNew },
{ Command::Type::STASH, PerformCommandStash },
{ Command::Type::ZERO, PerformCommandZero },
// clang-format on
};
CHECK_EQ(static_cast<size_t>(Command::Type::LAST), command_map.size());
return PerformBlockImageUpdate(name, state, argv, command_map, false);
}
Value* RangeSha1Fn(const char* name, State* state, const std::vector<std::unique_ptr<Expr>>& argv) {
if (argv.size() != 2) {
ErrorAbort(state, kArgsParsingFailure, "range_sha1 expects 2 arguments, got %zu", argv.size());
return StringValue("");
}
std::vector<std::unique_ptr<Value>> args;
if (!ReadValueArgs(state, argv, &args)) {
return nullptr;
}
const std::unique_ptr<Value>& blockdev_filename = args[0];
const std::unique_ptr<Value>& ranges = args[1];
if (blockdev_filename->type != Value::Type::STRING) {
ErrorAbort(state, kArgsParsingFailure, "blockdev_filename argument to %s must be string", name);
return StringValue("");
}
if (ranges->type != Value::Type::STRING) {
ErrorAbort(state, kArgsParsingFailure, "ranges argument to %s must be string", name);
return StringValue("");
}
android::base::unique_fd fd(open(blockdev_filename->data.c_str(), O_RDWR));
if (fd == -1) {
CauseCode cause_code = errno == EIO ? kEioFailure : kFileOpenFailure;
ErrorAbort(state, cause_code, "open \"%s\" failed: %s", blockdev_filename->data.c_str(),
strerror(errno));
return StringValue("");
}
RangeSet rs = RangeSet::Parse(ranges->data);
CHECK(static_cast<bool>(rs));
SHA_CTX ctx;
SHA1_Init(&ctx);
std::vector<uint8_t> buffer(BLOCKSIZE);
for (const auto& [begin, end] : rs) {
if (!check_lseek(fd, static_cast<off64_t>(begin) * BLOCKSIZE, SEEK_SET)) {
ErrorAbort(state, kLseekFailure, "failed to seek %s: %s", blockdev_filename->data.c_str(),
strerror(errno));
return StringValue("");
}
for (size_t j = begin; j < end; ++j) {
if (!android::base::ReadFully(fd, buffer.data(), BLOCKSIZE)) {
CauseCode cause_code = errno == EIO ? kEioFailure : kFreadFailure;
ErrorAbort(state, cause_code, "failed to read %s: %s", blockdev_filename->data.c_str(),
strerror(errno));
return StringValue("");
}
SHA1_Update(&ctx, buffer.data(), BLOCKSIZE);
}
}
uint8_t digest[SHA_DIGEST_LENGTH];
SHA1_Final(digest, &ctx);
return StringValue(print_sha1(digest));
}
// This function checks if a device has been remounted R/W prior to an incremental
// OTA update. This is an common cause of update abortion. The function reads the
// 1st block of each partition and check for mounting time/count. It return string "t"
// if executes successfully and an empty string otherwise.
Value* CheckFirstBlockFn(const char* name, State* state,
const std::vector<std::unique_ptr<Expr>>& argv) {
if (argv.size() != 1) {
ErrorAbort(state, kArgsParsingFailure, "check_first_block expects 1 argument, got %zu",
argv.size());
return StringValue("");
}
std::vector<std::unique_ptr<Value>> args;
if (!ReadValueArgs(state, argv, &args)) {
return nullptr;
}
const std::unique_ptr<Value>& arg_filename = args[0];
if (arg_filename->type != Value::Type::STRING) {
ErrorAbort(state, kArgsParsingFailure, "filename argument to %s must be string", name);
return StringValue("");
}
android::base::unique_fd fd(open(arg_filename->data.c_str(), O_RDONLY));
if (fd == -1) {
CauseCode cause_code = errno == EIO ? kEioFailure : kFileOpenFailure;
ErrorAbort(state, cause_code, "open \"%s\" failed: %s", arg_filename->data.c_str(),
strerror(errno));
return StringValue("");
}
RangeSet blk0(std::vector<Range>{ Range{ 0, 1 } });
std::vector<uint8_t> block0_buffer(BLOCKSIZE);
if (ReadBlocks(blk0, &block0_buffer, fd) == -1) {
CauseCode cause_code = errno == EIO ? kEioFailure : kFreadFailure;
ErrorAbort(state, cause_code, "failed to read %s: %s", arg_filename->data.c_str(),
strerror(errno));
return StringValue("");
}
// https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout
// Super block starts from block 0, offset 0x400
// 0x2C: len32 Mount time
// 0x30: len32 Write time
// 0x34: len16 Number of mounts since the last fsck
// 0x38: len16 Magic signature 0xEF53
time_t mount_time = *reinterpret_cast<uint32_t*>(&block0_buffer[0x400 + 0x2C]);
uint16_t mount_count = *reinterpret_cast<uint16_t*>(&block0_buffer[0x400 + 0x34]);
if (mount_count > 0) {
uiPrintf(state, "Device was remounted R/W %" PRIu16 " times", mount_count);
uiPrintf(state, "Last remount happened on %s", ctime(&mount_time));
}
return StringValue("t");
}
Value* BlockImageRecoverFn(const char* name, State* state,
const std::vector<std::unique_ptr<Expr>>& argv) {
if (argv.size() != 2) {
ErrorAbort(state, kArgsParsingFailure, "block_image_recover expects 2 arguments, got %zu",
argv.size());
return StringValue("");
}
std::vector<std::unique_ptr<Value>> args;
if (!ReadValueArgs(state, argv, &args)) {
return nullptr;
}
const std::unique_ptr<Value>& filename = args[0];
const std::unique_ptr<Value>& ranges = args[1];
if (filename->type != Value::Type::STRING) {
ErrorAbort(state, kArgsParsingFailure, "filename argument to %s must be string", name);
return StringValue("");
}
if (ranges->type != Value::Type::STRING) {
ErrorAbort(state, kArgsParsingFailure, "ranges argument to %s must be string", name);
return StringValue("");
}
RangeSet rs = RangeSet::Parse(ranges->data);
if (!rs) {
ErrorAbort(state, kArgsParsingFailure, "failed to parse ranges: %s", ranges->data.c_str());
return StringValue("");
}
// Output notice to log when recover is attempted
LOG(INFO) << filename->data << " image corrupted, attempting to recover...";
// When opened with O_RDWR, libfec rewrites corrupted blocks when they are read
fec::io fh(filename->data, O_RDWR);
if (!fh) {
ErrorAbort(state, kLibfecFailure, "fec_open \"%s\" failed: %s", filename->data.c_str(),
strerror(errno));
return StringValue("");
}
if (!fh.has_ecc() || !fh.has_verity()) {
ErrorAbort(state, kLibfecFailure, "unable to use metadata to correct errors");
return StringValue("");
}
fec_status status;
if (!fh.get_status(status)) {
ErrorAbort(state, kLibfecFailure, "failed to read FEC status");
return StringValue("");
}
uint8_t buffer[BLOCKSIZE];
for (const auto& [begin, end] : rs) {
for (size_t j = begin; j < end; ++j) {
// Stay within the data area, libfec validates and corrects metadata
if (status.data_size <= static_cast<uint64_t>(j) * BLOCKSIZE) {
continue;
}
if (fh.pread(buffer, BLOCKSIZE, static_cast<off64_t>(j) * BLOCKSIZE) != BLOCKSIZE) {
ErrorAbort(state, kLibfecFailure, "failed to recover %s (block %zu): %s",
filename->data.c_str(), j, strerror(errno));
return StringValue("");
}
// If we want to be able to recover from a situation where rewriting a corrected
// block doesn't guarantee the same data will be returned when re-read later, we
// can save a copy of corrected blocks to /cache. Note:
//
// 1. Maximum space required from /cache is the same as the maximum number of
// corrupted blocks we can correct. For RS(255, 253) and a 2 GiB partition,
// this would be ~16 MiB, for example.
//
// 2. To find out if this block was corrupted, call fec_get_status after each
// read and check if the errors field value has increased.
}
}
LOG(INFO) << "..." << filename->data << " image recovered successfully.";
return StringValue("t");
}
void RegisterBlockImageFunctions() {
RegisterFunction("block_image_verify", BlockImageVerifyFn);
RegisterFunction("block_image_update", BlockImageUpdateFn);
RegisterFunction("block_image_recover", BlockImageRecoverFn);
RegisterFunction("check_first_block", CheckFirstBlockFn);
RegisterFunction("range_sha1", RangeSha1Fn);
}
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