diff options
| -rw-r--r-- | lib/sqfs/data_writer.c | 151 |
1 files changed, 145 insertions, 6 deletions
diff --git a/lib/sqfs/data_writer.c b/lib/sqfs/data_writer.c index c350526..496d636 100644 --- a/lib/sqfs/data_writer.c +++ b/lib/sqfs/data_writer.c @@ -7,6 +7,7 @@ #include <stdlib.h> #include <string.h> +#include <unistd.h> #include <stdio.h> #include <errno.h> @@ -153,6 +154,114 @@ static file_info_t *fragment_by_chksum(file_info_t *fi, uint32_t chksum, return it; } +static size_t get_block_count(file_info_t *fi, size_t block_size) +{ + size_t count = fi->size / block_size; + + if ((fi->size % block_size != 0) && + (fi->fragment == 0xFFFFFFFF || + fi->fragment_offset == 0xFFFFFFFF)) { + ++count; + } + + while (count > 0 && fi->blocks[count - 1].size == 0) + --count; + + return count; +} + +static size_t find_first_match(file_info_t *file, file_info_t *cmp, + size_t idx, size_t cmp_blk_count) +{ + size_t i; + + for (i = 0; i < cmp_blk_count; ++i) { + if (memcmp(file->blocks + idx, cmp->blocks + i, + sizeof(file->blocks[idx])) == 0) { + break; + } + } + + return i; +} + +static uint64_t find_equal_blocks(file_info_t *file, file_info_t *list, + size_t block_size) +{ + size_t start, first_match, i, j, block_count, cmp_blk_count; + uint64_t location; + file_info_t *it; + + block_count = get_block_count(file, block_size); + if (block_count == 0) + return 0; + + for (start = 0; start < block_count; ++start) { + if (file->blocks[start].size != 0) + break; + } + + location = 0; + + for (it = list; it != NULL; it = it->next) { + if (it == file) { + it = NULL; + break; + } + + /* XXX: list assumed to be processed in order, prevent us from + re-checking files we know are duplicates */ + if (it->startblock < location) + continue; + + location = it->startblock; + + cmp_blk_count = get_block_count(it, block_size); + if (cmp_blk_count == 0) + continue; + + first_match = find_first_match(file, it, start, cmp_blk_count); + if (first_match == cmp_blk_count) + continue; + + i = start; + j = first_match; + + while (i < block_count && j < cmp_blk_count) { + if (file->blocks[i].size == 0) { + ++i; + continue; + } + + if (it->blocks[j].size == 0) { + ++j; + continue; + } + + if (memcmp(it->blocks + j, file->blocks + i, + sizeof(file->blocks[i])) != 0) { + break; + } + + ++i; + ++j; + } + + if (i == block_count) + break; + } + + if (it == NULL) + return 0; + + location = it->startblock; + + for (i = 0; i < first_match; ++i) + location += it->blocks[i].size & ((1 << 24) - 1); + + return location; +} + static int flush_data_block(data_writer_t *data, size_t size, file_info_t *fi, int flags, file_info_t *list) { @@ -204,8 +313,13 @@ static int flush_data_block(data_writer_t *data, size_t size, return 0; } -static int begin_file(data_writer_t *data, file_info_t *fi, int flags) +static int begin_file(data_writer_t *data, file_info_t *fi, + int flags, off_t *start) { + *start = lseek(data->outfd, 0, SEEK_CUR); + if (*start == (off_t)-1) + goto fail_seek; + if ((flags & DW_ALLIGN_DEVBLK) && allign_file(data) != 0) return -1; @@ -213,14 +327,37 @@ static int begin_file(data_writer_t *data, file_info_t *fi, int flags) fi->sparse = 0; data->block_idx = 0; return 0; +fail_seek: + perror("querying current position on squashfs image"); + return -1; } -static int end_file(data_writer_t *data, int flags) +static int end_file(data_writer_t *data, file_info_t *fi, + off_t start, int flags, file_info_t *list) { + uint64_t ref; + if ((flags & DW_ALLIGN_DEVBLK) && allign_file(data) != 0) return -1; + ref = find_equal_blocks(fi, list, data->super->block_size); + + if (ref > 0) { + fi->startblock = ref; + + if (lseek(data->outfd, start, SEEK_SET) == (off_t)-1) + goto fail_seek; + + if (ftruncate(data->outfd, start)) + goto fail_truncate; + } return 0; +fail_seek: + perror("seeking on squashfs image after file deduplication"); + return -1; +fail_truncate: + perror("truncating squashfs image after file deduplication"); + return -1; } int write_data_from_fd(data_writer_t *data, file_info_t *fi, @@ -228,8 +365,9 @@ int write_data_from_fd(data_writer_t *data, file_info_t *fi, { uint64_t count; size_t diff; + off_t start; - if (begin_file(data, fi, flags)) + if (begin_file(data, fi, flags, &start)) return -1; for (count = fi->size; count != 0; count -= diff) { @@ -243,7 +381,7 @@ int write_data_from_fd(data_writer_t *data, file_info_t *fi, return -1; } - return end_file(data, flags); + return end_file(data, fi, start, flags, list); } int write_data_from_fd_condensed(data_writer_t *data, file_info_t *fi, @@ -253,8 +391,9 @@ int write_data_from_fd_condensed(data_writer_t *data, file_info_t *fi, size_t start, count, diff; sparse_map_t *m; uint64_t offset; + off_t location; - if (begin_file(data, fi, flags)) + if (begin_file(data, fi, flags, &location)) return -1; if (map != NULL) { @@ -304,7 +443,7 @@ int write_data_from_fd_condensed(data_writer_t *data, file_info_t *fi, return -1; } - return end_file(data, flags); + return end_file(data, fi, location, flags, list); fail_map_size: fprintf(stderr, "%s: sparse file map spans beyond file size\n", fi->input_file); |