diff --git a/chunk-format.c b/chunk-format.c index 3f5cc9b5ddf48c..e836a121c5ca81 100644 --- a/chunk-format.c +++ b/chunk-format.c @@ -173,6 +173,59 @@ int read_table_of_contents(struct chunkfile *cf, return 0; } +int read_trailing_table_of_contents(struct chunkfile *cf, + const unsigned char *mfile, + size_t mfile_size) +{ + int i; + uint32_t chunk_id; + const unsigned char *table_of_contents = mfile + mfile_size - the_hash_algo->rawsz; + + while (1) { + uint64_t chunk_offset; + + table_of_contents -= CHUNK_TOC_ENTRY_SIZE; + + chunk_id = get_be32(table_of_contents); + chunk_offset = get_be64(table_of_contents + 4); + + /* Calculate the previous chunk size, if it exists. */ + if (cf->chunks_nr) { + off_t previous_offset = cf->chunks[cf->chunks_nr - 1].offset; + + if (chunk_offset < previous_offset || + chunk_offset > table_of_contents - mfile) { + error(_("improper chunk offset(s) %"PRIx64" and %"PRIx64""), + previous_offset, chunk_offset); + return -1; + } + + cf->chunks[cf->chunks_nr - 1].size = chunk_offset - previous_offset; + } + + /* Stop at the null chunk. We only need it for the last size. */ + if (!chunk_id) + break; + + for (i = 0; i < cf->chunks_nr; i++) { + if (cf->chunks[i].id == chunk_id) { + error(_("duplicate chunk ID %"PRIx32" found"), + chunk_id); + return -1; + } + } + + ALLOC_GROW(cf->chunks, cf->chunks_nr + 1, cf->chunks_alloc); + + cf->chunks[cf->chunks_nr].id = chunk_id; + cf->chunks[cf->chunks_nr].start = mfile + chunk_offset; + cf->chunks[cf->chunks_nr].offset = chunk_offset; + cf->chunks_nr++; + } + + return 0; +} + static int pair_chunk_fn(const unsigned char *chunk_start, size_t chunk_size, void *data) diff --git a/chunk-format.h b/chunk-format.h index 39e8967e95075b..acb8dfbce8039d 100644 --- a/chunk-format.h +++ b/chunk-format.h @@ -46,6 +46,15 @@ int read_table_of_contents(struct chunkfile *cf, uint64_t toc_offset, int toc_length); +/** + * Read the given chunkfile, but read the table of contents from the + * end of the given mfile. The file is expected to be a hashfile with + * the_hash_file->rawsz bytes at the end storing the hash. + */ +int read_trailing_table_of_contents(struct chunkfile *cf, + const unsigned char *mfile, + size_t mfile_size); + #define CHUNK_NOT_FOUND (-2) /*