From 25dd0386fe69460cd1d39de116197dd2c7bf9ec2 Mon Sep 17 00:00:00 2001 From: Yabin Cui Date: Mon, 1 Feb 2016 11:40:37 -0800 Subject: [PATCH] uncrypt: generate map file by renaming tmp file. Writing map file directly can break consistency in map file if it fails in the middle. Instead, we write a temporary file and rename the temporary file to map file. Bug: 26883096 Change-Id: I5e99e942e1b75e758af5f7a48f8a08a0b0041d6a --- uncrypt/uncrypt.cpp | 176 ++++++++++++++++++++++++-------------------- 1 file changed, 97 insertions(+), 79 deletions(-) diff --git a/uncrypt/uncrypt.cpp b/uncrypt/uncrypt.cpp index de7e4818..098a7a97 100644 --- a/uncrypt/uncrypt.cpp +++ b/uncrypt/uncrypt.cpp @@ -42,6 +42,7 @@ #include #include #include +#include #include #include #include @@ -52,9 +53,12 @@ #include #include +#include #include +#include #include +#include #include #include #include @@ -78,44 +82,22 @@ static int write_at_offset(unsigned char* buffer, size_t size, int wfd, off64_t ALOGE("error seeking to offset %" PRId64 ": %s\n", offset, strerror(errno)); return -1; } - size_t written = 0; - while (written < size) { - ssize_t wrote = TEMP_FAILURE_RETRY(write(wfd, buffer + written, size - written)); - if (wrote == -1) { - ALOGE("error writing offset %" PRId64 ": %s\n", - offset + static_cast(written), strerror(errno)); - return -1; - } - written += wrote; + if (!android::base::WriteFully(wfd, buffer, size)) { + ALOGE("error writing offset %" PRId64 ": %s\n", offset, strerror(errno)); + return -1; } return 0; } -static void add_block_to_ranges(int** ranges, int* range_alloc, int* range_used, int new_block) { - // If the current block start is < 0, set the start to the new - // block. (This only happens for the very first block of the very - // first range.) - if ((*ranges)[*range_used*2-2] < 0) { - (*ranges)[*range_used*2-2] = new_block; - (*ranges)[*range_used*2-1] = new_block; - } - - if (new_block == (*ranges)[*range_used*2-1]) { +static void add_block_to_ranges(std::vector& ranges, int new_block) { + if (!ranges.empty() && new_block == ranges.back()) { // If the new block comes immediately after the current range, // all we have to do is extend the current range. - ++(*ranges)[*range_used*2-1]; + ++ranges.back(); } else { // We need to start a new range. - - // If there isn't enough room in the array, we need to expand it. - if (*range_used >= *range_alloc) { - *range_alloc *= 2; - *ranges = reinterpret_cast(realloc(*ranges, *range_alloc * 2 * sizeof(int))); - } - - ++*range_used; - (*ranges)[*range_used*2-2] = new_block; - (*ranges)[*range_used*2-1] = new_block+1; + ranges.push_back(new_block); + ranges.push_back(new_block + 1); } } @@ -183,12 +165,17 @@ static bool find_uncrypt_package(std::string& package_name) static int produce_block_map(const char* path, const char* map_file, const char* blk_dev, bool encrypted, int status_fd) { - int mapfd = open(map_file, O_WRONLY | O_CREAT | O_SYNC, S_IRUSR | S_IWUSR); - if (mapfd == -1) { - ALOGE("failed to open %s\n", map_file); + std::string err; + if (!android::base::RemoveFileIfExists(map_file, &err)) { + ALOGE("failed to remove the existing map file %s: %s\n", map_file, err.c_str()); + return -1; + } + std::string tmp_map_file = std::string(map_file) + ".tmp"; + unique_fd mapfd(open(tmp_map_file.c_str(), O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR)); + if (!mapfd) { + ALOGE("failed to open %s: %s\n", tmp_map_file.c_str(), strerror(errno)); return -1; } - std::unique_ptr mapf(fdopen(mapfd, "w"), fclose); // Make sure we can write to the status_file. if (!android::base::WriteStringToFd("0\n", status_fd)) { @@ -207,37 +194,32 @@ static int produce_block_map(const char* path, const char* map_file, const char* int blocks = ((sb.st_size-1) / sb.st_blksize) + 1; ALOGI(" file size: %" PRId64 " bytes, %d blocks\n", sb.st_size, blocks); - int range_alloc = 1; - int range_used = 1; - int* ranges = reinterpret_cast(malloc(range_alloc * 2 * sizeof(int))); - ranges[0] = -1; - ranges[1] = -1; + std::vector ranges; - fprintf(mapf.get(), "%s\n%" PRId64 " %ld\n", - blk_dev, sb.st_size, static_cast(sb.st_blksize)); + std::string s = android::base::StringPrintf("%s\n%" PRId64 " %ld\n", + blk_dev, sb.st_size, static_cast(sb.st_blksize)); + if (!android::base::WriteStringToFd(s, mapfd.get())) { + ALOGE("failed to write %s: %s\n", tmp_map_file.c_str(), strerror(errno)); + return -1; + } - unsigned char* buffers[WINDOW_SIZE]; + std::vector> buffers; if (encrypted) { - for (size_t i = 0; i < WINDOW_SIZE; ++i) { - buffers[i] = reinterpret_cast(malloc(sb.st_blksize)); - } + buffers.resize(WINDOW_SIZE, std::vector(sb.st_blksize)); } int head_block = 0; int head = 0, tail = 0; - int fd = open(path, O_RDONLY); - unique_fd fd_holder(fd); - if (fd == -1) { - ALOGE("failed to open fd for reading: %s\n", strerror(errno)); + unique_fd fd(open(path, O_RDONLY)); + if (!fd) { + ALOGE("failed to open %s for reading: %s\n", path, strerror(errno)); return -1; } - int wfd = -1; - unique_fd wfd_holder(wfd); + unique_fd wfd(-1); if (encrypted) { wfd = open(blk_dev, O_WRONLY); - wfd_holder = unique_fd(wfd); - if (wfd == -1) { + if (!wfd) { ALOGE("failed to open fd for writing: %s\n", strerror(errno)); return -1; } @@ -256,13 +238,13 @@ static int produce_block_map(const char* path, const char* map_file, const char* if ((tail+1) % WINDOW_SIZE == head) { // write out head buffer int block = head_block; - if (ioctl(fd, FIBMAP, &block) != 0) { + if (ioctl(fd.get(), FIBMAP, &block) != 0) { ALOGE("failed to find block %d\n", head_block); return -1; } - add_block_to_ranges(&ranges, &range_alloc, &range_used, block); + add_block_to_ranges(ranges, block); if (encrypted) { - if (write_at_offset(buffers[head], sb.st_blksize, wfd, + if (write_at_offset(buffers[head].data(), sb.st_blksize, wfd.get(), static_cast(sb.st_blksize) * block) != 0) { return -1; } @@ -273,17 +255,13 @@ static int produce_block_map(const char* path, const char* map_file, const char* // read next block to tail if (encrypted) { - size_t so_far = 0; - while (so_far < static_cast(sb.st_blksize) && pos < sb.st_size) { - ssize_t this_read = - TEMP_FAILURE_RETRY(read(fd, buffers[tail] + so_far, sb.st_blksize - so_far)); - if (this_read == -1) { - ALOGE("failed to read: %s\n", strerror(errno)); - return -1; - } - so_far += this_read; - pos += this_read; + size_t to_read = static_cast( + std::min(static_cast(sb.st_blksize), sb.st_size - pos)); + if (!android::base::ReadFully(fd.get(), buffers[tail].data(), to_read)) { + ALOGE("failed to read: %s\n", strerror(errno)); + return -1; } + pos += to_read; } else { // If we're not encrypting; we don't need to actually read // anything, just skip pos forward as if we'd read a @@ -296,13 +274,13 @@ static int produce_block_map(const char* path, const char* map_file, const char* while (head != tail) { // write out head buffer int block = head_block; - if (ioctl(fd, FIBMAP, &block) != 0) { + if (ioctl(fd.get(), FIBMAP, &block) != 0) { ALOGE("failed to find block %d\n", head_block); return -1; } - add_block_to_ranges(&ranges, &range_alloc, &range_used, block); + add_block_to_ranges(ranges, block); if (encrypted) { - if (write_at_offset(buffers[head], sb.st_blksize, wfd, + if (write_at_offset(buffers[head].data(), sb.st_blksize, wfd.get(), static_cast(sb.st_blksize) * block) != 0) { return -1; } @@ -311,22 +289,62 @@ static int produce_block_map(const char* path, const char* map_file, const char* ++head_block; } - fprintf(mapf.get(), "%d\n", range_used); - for (int i = 0; i < range_used; ++i) { - fprintf(mapf.get(), "%d %d\n", ranges[i*2], ranges[i*2+1]); - } - - if (fsync(mapfd) == -1) { - ALOGE("failed to fsync \"%s\": %s\n", map_file, strerror(errno)); + if (!android::base::WriteStringToFd( + android::base::StringPrintf("%zu\n", ranges.size() / 2), mapfd.get())) { + ALOGE("failed to write %s: %s\n", tmp_map_file.c_str(), strerror(errno)); return -1; } - if (encrypted) { - if (fsync(wfd) == -1) { - ALOGE("failed to fsync \"%s\": %s\n", blk_dev, strerror(errno)); + for (size_t i = 0; i < ranges.size(); i += 2) { + if (!android::base::WriteStringToFd( + android::base::StringPrintf("%d %d\n", ranges[i], ranges[i+1]), mapfd.get())) { + ALOGE("failed to write %s: %s\n", tmp_map_file.c_str(), strerror(errno)); return -1; } } + if (fsync(mapfd.get()) == -1) { + ALOGE("failed to fsync \"%s\": %s\n", tmp_map_file.c_str(), strerror(errno)); + return -1; + } + if (close(mapfd.get() == -1)) { + ALOGE("failed to close %s: %s\n", tmp_map_file.c_str(), strerror(errno)); + return -1; + } + mapfd = -1; + + if (encrypted) { + if (fsync(wfd.get()) == -1) { + ALOGE("failed to fsync \"%s\": %s\n", blk_dev, strerror(errno)); + return -1; + } + if (close(wfd.get()) == -1) { + ALOGE("failed to close %s: %s\n", blk_dev, strerror(errno)); + return -1; + } + wfd = -1; + } + + if (rename(tmp_map_file.c_str(), map_file) == -1) { + ALOGE("failed to rename %s to %s: %s\n", tmp_map_file.c_str(), map_file, strerror(errno)); + return -1; + } + // Sync dir to make rename() result written to disk. + std::string file_name = map_file; + std::string dir_name = dirname(&file_name[0]); + unique_fd dfd(open(dir_name.c_str(), O_RDONLY | O_DIRECTORY)); + if (!dfd) { + ALOGE("failed to open dir %s: %s\n", dir_name.c_str(), strerror(errno)); + return -1; + } + if (fsync(dfd.get()) == -1) { + ALOGE("failed to fsync %s: %s\n", dir_name.c_str(), strerror(errno)); + return -1; + } + if (close(dfd.get() == -1)) { + ALOGE("failed to close %s: %s\n", dir_name.c_str(), strerror(errno)); + return -1; + } + dfd = -1; return 0; }