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Diffstat (limited to 'contrib/android/ext2simg.c')
| -rw-r--r-- | contrib/android/ext2simg.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/contrib/android/ext2simg.c b/contrib/android/ext2simg.c new file mode 100644 index 0000000..017e16f --- /dev/null +++ b/contrib/android/ext2simg.c @@ -0,0 +1,224 @@ +/* + * Copyright (C) 2016 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 <libgen.h> +#include <unistd.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <ext2fs/ext2fs.h> +#include <et/com_err.h> +#include <sparse/sparse.h> + +struct { + int crc; + int sparse; + int gzip; + char *in_file; + char *out_file; + bool overwrite_input; +} params = { + .crc = 0, + .sparse = 1, + .gzip = 0, +}; + +#define ext2fs_fatal(Retval, Format, ...) \ + do { \ + com_err("error", Retval, Format, __VA_ARGS__); \ + exit(EXIT_FAILURE); \ + } while(0) + +#define sparse_fatal(Format) \ + do { \ + fprintf(stderr, "sparse: "Format); \ + exit(EXIT_FAILURE); \ + } while(0) + +static void usage(char *path) +{ + char *progname = basename(path); + + fprintf(stderr, "%s [ options ] <image or block device> <output image>\n" + " -c include CRC block\n" + " -z gzip output\n" + " -S don't use sparse output format\n", progname); +} + +static struct buf_item { + struct buf_item *next; + void *buf[0]; +} *buf_list; + +static void add_chunk(ext2_filsys fs, struct sparse_file *s, blk_t chunk_start, blk_t chunk_end) +{ + int retval; + unsigned int nb_blk = chunk_end - chunk_start; + size_t len = nb_blk * fs->blocksize; + int64_t offset = (int64_t)chunk_start * (int64_t)fs->blocksize; + + if (params.overwrite_input == false) { + if (sparse_file_add_file(s, params.in_file, offset, len, chunk_start) < 0) + sparse_fatal("adding data to the sparse file"); + } else { + /* + * The input file will be overwritten, make a copy of + * the blocks + */ + struct buf_item *bi = calloc(1, sizeof(struct buf_item) + len); + if (buf_list == NULL) + buf_list = bi; + else { + bi->next = buf_list; + buf_list = bi; + } + + retval = io_channel_read_blk64(fs->io, chunk_start, nb_blk, bi->buf); + if (retval < 0) + ext2fs_fatal(retval, "reading block %u - %u", chunk_start, chunk_end); + + if (sparse_file_add_data(s, bi->buf, len, chunk_start) < 0) + sparse_fatal("adding data to the sparse file"); + } +} + +static void free_chunks(void) +{ + struct buf_item *bi; + + while (buf_list) { + bi = buf_list->next; + free(buf_list); + buf_list = bi; + } +} + +static struct sparse_file *ext_to_sparse(const char *in_file) +{ + errcode_t retval; + ext2_filsys fs; + struct sparse_file *s; + int64_t chunk_start = -1; + blk_t first_blk, last_blk, nb_blk, cur_blk; + + retval = ext2fs_open(in_file, 0, 0, 0, unix_io_manager, &fs); + if (retval) + ext2fs_fatal(retval, "while reading %s", in_file); + + retval = ext2fs_read_block_bitmap(fs); + if (retval) + ext2fs_fatal(retval, "while reading block bitmap of %s", in_file); + + first_blk = ext2fs_get_block_bitmap_start2(fs->block_map); + last_blk = ext2fs_get_block_bitmap_end2(fs->block_map); + nb_blk = last_blk - first_blk + 1; + + s = sparse_file_new(fs->blocksize, (uint64_t)fs->blocksize * (uint64_t)nb_blk); + if (!s) + sparse_fatal("creating sparse file"); + + /* + * The sparse format encodes the size of a chunk (and its header) in a + * 32-bit unsigned integer (UINT32_MAX) + * When writing the chunk, the library uses a single call to write(). + * Linux's implementation of the 'write' syscall does not allow transfers + * larger than INT32_MAX (32-bit _and_ 64-bit systems). + * Make sure we do not create chunks larger than this limit. + */ + int64_t max_blk_per_chunk = (INT32_MAX - 12) / fs->blocksize; + + /* Iter on the blocks to merge contiguous chunk */ + for (cur_blk = first_blk; cur_blk <= last_blk; ++cur_blk) { + if (ext2fs_test_block_bitmap2(fs->block_map, cur_blk)) { + if (chunk_start == -1) { + chunk_start = cur_blk; + } else if (cur_blk - chunk_start + 1 == max_blk_per_chunk) { + add_chunk(fs, s, chunk_start, cur_blk); + chunk_start = -1; + } + } else if (chunk_start != -1) { + add_chunk(fs, s, chunk_start, cur_blk); + chunk_start = -1; + } + } + if (chunk_start != -1) + add_chunk(fs, s, chunk_start, cur_blk - 1); + + ext2fs_free(fs); + return s; +} + +static bool same_file(const char *in, const char *out) +{ + struct stat st1, st2; + + if (access(out, F_OK) == -1) + return false; + + if (lstat(in, &st1) == -1) + ext2fs_fatal(errno, "stat %s\n", in); + if (lstat(out, &st2) == -1) + ext2fs_fatal(errno, "stat %s\n", out); + return st1.st_ino == st2.st_ino; +} + +int main(int argc, char *argv[]) +{ + int opt; + int out_fd; + struct sparse_file *s; + + while ((opt = getopt(argc, argv, "czS")) != -1) { + switch(opt) { + case 'c': + params.crc = 1; + break; + case 'z': + params.gzip = 1; + break; + case 'S': + params.sparse = 0; + break; + default: + usage(argv[0]); + exit(EXIT_FAILURE); + } + } + if (optind + 1 >= argc) { + usage(argv[0]); + exit(EXIT_FAILURE); + } + params.in_file = strdup(argv[optind++]); + params.out_file = strdup(argv[optind]); + params.overwrite_input = same_file(params.in_file, params.out_file); + + s = ext_to_sparse(params.in_file); + + out_fd = open(params.out_file, O_WRONLY | O_CREAT | O_TRUNC, 0664); + if (out_fd == -1) + ext2fs_fatal(errno, "opening %s\n", params.out_file); + if (sparse_file_write(s, out_fd, params.gzip, params.sparse, params.crc) < 0) + sparse_fatal("writing sparse file"); + + sparse_file_destroy(s); + + free(params.in_file); + free(params.out_file); + free_chunks(); + close(out_fd); + + return 0; +} |