| #include "cache.h" |
| #include "pack.h" |
| #include "csum-file.h" |
| |
| void reset_pack_idx_option(struct pack_idx_option *opts) |
| { |
| memset(opts, 0, sizeof(*opts)); |
| opts->version = 2; |
| opts->off32_limit = 0x7fffffff; |
| } |
| |
| static int sha1_compare(const void *_a, const void *_b) |
| { |
| struct pack_idx_entry *a = *(struct pack_idx_entry **)_a; |
| struct pack_idx_entry *b = *(struct pack_idx_entry **)_b; |
| return oidcmp(&a->oid, &b->oid); |
| } |
| |
| static int cmp_uint32(const void *a_, const void *b_) |
| { |
| uint32_t a = *((uint32_t *)a_); |
| uint32_t b = *((uint32_t *)b_); |
| |
| return (a < b) ? -1 : (a != b); |
| } |
| |
| static int need_large_offset(off_t offset, const struct pack_idx_option *opts) |
| { |
| uint32_t ofsval; |
| |
| if ((offset >> 31) || (opts->off32_limit < offset)) |
| return 1; |
| if (!opts->anomaly_nr) |
| return 0; |
| ofsval = offset; |
| return !!bsearch(&ofsval, opts->anomaly, opts->anomaly_nr, |
| sizeof(ofsval), cmp_uint32); |
| } |
| |
| /* |
| * On entry *sha1 contains the pack content SHA1 hash, on exit it is |
| * the SHA1 hash of sorted object names. The objects array passed in |
| * will be sorted by SHA1 on exit. |
| */ |
| const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects, |
| int nr_objects, const struct pack_idx_option *opts, |
| const unsigned char *sha1) |
| { |
| struct hashfile *f; |
| struct pack_idx_entry **sorted_by_sha, **list, **last; |
| off_t last_obj_offset = 0; |
| uint32_t array[256]; |
| int i, fd; |
| uint32_t index_version; |
| |
| if (nr_objects) { |
| sorted_by_sha = objects; |
| list = sorted_by_sha; |
| last = sorted_by_sha + nr_objects; |
| for (i = 0; i < nr_objects; ++i) { |
| if (objects[i]->offset > last_obj_offset) |
| last_obj_offset = objects[i]->offset; |
| } |
| QSORT(sorted_by_sha, nr_objects, sha1_compare); |
| } |
| else |
| sorted_by_sha = list = last = NULL; |
| |
| if (opts->flags & WRITE_IDX_VERIFY) { |
| assert(index_name); |
| f = hashfd_check(index_name); |
| } else { |
| if (!index_name) { |
| struct strbuf tmp_file = STRBUF_INIT; |
| fd = odb_mkstemp(&tmp_file, "pack/tmp_idx_XXXXXX"); |
| index_name = strbuf_detach(&tmp_file, NULL); |
| } else { |
| unlink(index_name); |
| fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600); |
| if (fd < 0) |
| die_errno("unable to create '%s'", index_name); |
| } |
| f = hashfd(fd, index_name); |
| } |
| |
| /* if last object's offset is >= 2^31 we should use index V2 */ |
| index_version = need_large_offset(last_obj_offset, opts) ? 2 : opts->version; |
| |
| /* index versions 2 and above need a header */ |
| if (index_version >= 2) { |
| struct pack_idx_header hdr; |
| hdr.idx_signature = htonl(PACK_IDX_SIGNATURE); |
| hdr.idx_version = htonl(index_version); |
| hashwrite(f, &hdr, sizeof(hdr)); |
| } |
| |
| /* |
| * Write the first-level table (the list is sorted, |
| * but we use a 256-entry lookup to be able to avoid |
| * having to do eight extra binary search iterations). |
| */ |
| for (i = 0; i < 256; i++) { |
| struct pack_idx_entry **next = list; |
| while (next < last) { |
| struct pack_idx_entry *obj = *next; |
| if (obj->oid.hash[0] != i) |
| break; |
| next++; |
| } |
| array[i] = htonl(next - sorted_by_sha); |
| list = next; |
| } |
| hashwrite(f, array, 256 * 4); |
| |
| /* |
| * Write the actual SHA1 entries.. |
| */ |
| list = sorted_by_sha; |
| for (i = 0; i < nr_objects; i++) { |
| struct pack_idx_entry *obj = *list++; |
| if (index_version < 2) { |
| uint32_t offset = htonl(obj->offset); |
| hashwrite(f, &offset, 4); |
| } |
| hashwrite(f, obj->oid.hash, the_hash_algo->rawsz); |
| if ((opts->flags & WRITE_IDX_STRICT) && |
| (i && !oidcmp(&list[-2]->oid, &obj->oid))) |
| die("The same object %s appears twice in the pack", |
| oid_to_hex(&obj->oid)); |
| } |
| |
| if (index_version >= 2) { |
| unsigned int nr_large_offset = 0; |
| |
| /* write the crc32 table */ |
| list = sorted_by_sha; |
| for (i = 0; i < nr_objects; i++) { |
| struct pack_idx_entry *obj = *list++; |
| uint32_t crc32_val = htonl(obj->crc32); |
| hashwrite(f, &crc32_val, 4); |
| } |
| |
| /* write the 32-bit offset table */ |
| list = sorted_by_sha; |
| for (i = 0; i < nr_objects; i++) { |
| struct pack_idx_entry *obj = *list++; |
| uint32_t offset; |
| |
| offset = (need_large_offset(obj->offset, opts) |
| ? (0x80000000 | nr_large_offset++) |
| : obj->offset); |
| offset = htonl(offset); |
| hashwrite(f, &offset, 4); |
| } |
| |
| /* write the large offset table */ |
| list = sorted_by_sha; |
| while (nr_large_offset) { |
| struct pack_idx_entry *obj = *list++; |
| uint64_t offset = obj->offset; |
| uint32_t split[2]; |
| |
| if (!need_large_offset(offset, opts)) |
| continue; |
| split[0] = htonl(offset >> 32); |
| split[1] = htonl(offset & 0xffffffff); |
| hashwrite(f, split, 8); |
| nr_large_offset--; |
| } |
| } |
| |
| hashwrite(f, sha1, the_hash_algo->rawsz); |
| hashclose(f, NULL, ((opts->flags & WRITE_IDX_VERIFY) |
| ? CSUM_CLOSE : CSUM_FSYNC)); |
| return index_name; |
| } |
| |
| off_t write_pack_header(struct hashfile *f, uint32_t nr_entries) |
| { |
| struct pack_header hdr; |
| |
| hdr.hdr_signature = htonl(PACK_SIGNATURE); |
| hdr.hdr_version = htonl(PACK_VERSION); |
| hdr.hdr_entries = htonl(nr_entries); |
| hashwrite(f, &hdr, sizeof(hdr)); |
| return sizeof(hdr); |
| } |
| |
| /* |
| * Update pack header with object_count and compute new SHA1 for pack data |
| * associated to pack_fd, and write that SHA1 at the end. That new SHA1 |
| * is also returned in new_pack_sha1. |
| * |
| * If partial_pack_sha1 is non null, then the SHA1 of the existing pack |
| * (without the header update) is computed and validated against the |
| * one provided in partial_pack_sha1. The validation is performed at |
| * partial_pack_offset bytes in the pack file. The SHA1 of the remaining |
| * data (i.e. from partial_pack_offset to the end) is then computed and |
| * returned in partial_pack_sha1. |
| * |
| * Note that new_pack_sha1 is updated last, so both new_pack_sha1 and |
| * partial_pack_sha1 can refer to the same buffer if the caller is not |
| * interested in the resulting SHA1 of pack data above partial_pack_offset. |
| */ |
| void fixup_pack_header_footer(int pack_fd, |
| unsigned char *new_pack_hash, |
| const char *pack_name, |
| uint32_t object_count, |
| unsigned char *partial_pack_hash, |
| off_t partial_pack_offset) |
| { |
| int aligned_sz, buf_sz = 8 * 1024; |
| git_hash_ctx old_hash_ctx, new_hash_ctx; |
| struct pack_header hdr; |
| char *buf; |
| ssize_t read_result; |
| |
| the_hash_algo->init_fn(&old_hash_ctx); |
| the_hash_algo->init_fn(&new_hash_ctx); |
| |
| if (lseek(pack_fd, 0, SEEK_SET) != 0) |
| die_errno("Failed seeking to start of '%s'", pack_name); |
| read_result = read_in_full(pack_fd, &hdr, sizeof(hdr)); |
| if (read_result < 0) |
| die_errno("Unable to reread header of '%s'", pack_name); |
| else if (read_result != sizeof(hdr)) |
| die_errno("Unexpected short read for header of '%s'", |
| pack_name); |
| if (lseek(pack_fd, 0, SEEK_SET) != 0) |
| die_errno("Failed seeking to start of '%s'", pack_name); |
| the_hash_algo->update_fn(&old_hash_ctx, &hdr, sizeof(hdr)); |
| hdr.hdr_entries = htonl(object_count); |
| the_hash_algo->update_fn(&new_hash_ctx, &hdr, sizeof(hdr)); |
| write_or_die(pack_fd, &hdr, sizeof(hdr)); |
| partial_pack_offset -= sizeof(hdr); |
| |
| buf = xmalloc(buf_sz); |
| aligned_sz = buf_sz - sizeof(hdr); |
| for (;;) { |
| ssize_t m, n; |
| m = (partial_pack_hash && partial_pack_offset < aligned_sz) ? |
| partial_pack_offset : aligned_sz; |
| n = xread(pack_fd, buf, m); |
| if (!n) |
| break; |
| if (n < 0) |
| die_errno("Failed to checksum '%s'", pack_name); |
| the_hash_algo->update_fn(&new_hash_ctx, buf, n); |
| |
| aligned_sz -= n; |
| if (!aligned_sz) |
| aligned_sz = buf_sz; |
| |
| if (!partial_pack_hash) |
| continue; |
| |
| the_hash_algo->update_fn(&old_hash_ctx, buf, n); |
| partial_pack_offset -= n; |
| if (partial_pack_offset == 0) { |
| unsigned char hash[GIT_MAX_RAWSZ]; |
| the_hash_algo->final_fn(hash, &old_hash_ctx); |
| if (hashcmp(hash, partial_pack_hash) != 0) |
| die("Unexpected checksum for %s " |
| "(disk corruption?)", pack_name); |
| /* |
| * Now let's compute the SHA1 of the remainder of the |
| * pack, which also means making partial_pack_offset |
| * big enough not to matter anymore. |
| */ |
| the_hash_algo->init_fn(&old_hash_ctx); |
| partial_pack_offset = ~partial_pack_offset; |
| partial_pack_offset -= MSB(partial_pack_offset, 1); |
| } |
| } |
| free(buf); |
| |
| if (partial_pack_hash) |
| the_hash_algo->final_fn(partial_pack_hash, &old_hash_ctx); |
| the_hash_algo->final_fn(new_pack_hash, &new_hash_ctx); |
| write_or_die(pack_fd, new_pack_hash, the_hash_algo->rawsz); |
| fsync_or_die(pack_fd, pack_name); |
| } |
| |
| char *index_pack_lockfile(int ip_out) |
| { |
| char packname[GIT_MAX_HEXSZ + 6]; |
| const int len = the_hash_algo->hexsz + 6; |
| |
| /* |
| * The first thing we expect from index-pack's output |
| * is "pack\t%40s\n" or "keep\t%40s\n" (46 bytes) where |
| * %40s is the newly created pack SHA1 name. In the "keep" |
| * case, we need it to remove the corresponding .keep file |
| * later on. If we don't get that then tough luck with it. |
| */ |
| if (read_in_full(ip_out, packname, len) == len && packname[len-1] == '\n') { |
| const char *name; |
| packname[len-1] = 0; |
| if (skip_prefix(packname, "keep\t", &name)) |
| return xstrfmt("%s/pack/pack-%s.keep", |
| get_object_directory(), name); |
| } |
| return NULL; |
| } |
| |
| /* |
| * The per-object header is a pretty dense thing, which is |
| * - first byte: low four bits are "size", then three bits of "type", |
| * and the high bit is "size continues". |
| * - each byte afterwards: low seven bits are size continuation, |
| * with the high bit being "size continues" |
| */ |
| int encode_in_pack_object_header(unsigned char *hdr, int hdr_len, |
| enum object_type type, uintmax_t size) |
| { |
| int n = 1; |
| unsigned char c; |
| |
| if (type < OBJ_COMMIT || type > OBJ_REF_DELTA) |
| die("bad type %d", type); |
| |
| c = (type << 4) | (size & 15); |
| size >>= 4; |
| while (size) { |
| if (n == hdr_len) |
| die("object size is too enormous to format"); |
| *hdr++ = c | 0x80; |
| c = size & 0x7f; |
| size >>= 7; |
| n++; |
| } |
| *hdr = c; |
| return n; |
| } |
| |
| struct hashfile *create_tmp_packfile(char **pack_tmp_name) |
| { |
| struct strbuf tmpname = STRBUF_INIT; |
| int fd; |
| |
| fd = odb_mkstemp(&tmpname, "pack/tmp_pack_XXXXXX"); |
| *pack_tmp_name = strbuf_detach(&tmpname, NULL); |
| return hashfd(fd, *pack_tmp_name); |
| } |
| |
| void finish_tmp_packfile(struct strbuf *name_buffer, |
| const char *pack_tmp_name, |
| struct pack_idx_entry **written_list, |
| uint32_t nr_written, |
| struct pack_idx_option *pack_idx_opts, |
| unsigned char sha1[]) |
| { |
| const char *idx_tmp_name; |
| int basename_len = name_buffer->len; |
| |
| if (adjust_shared_perm(pack_tmp_name)) |
| die_errno("unable to make temporary pack file readable"); |
| |
| idx_tmp_name = write_idx_file(NULL, written_list, nr_written, |
| pack_idx_opts, sha1); |
| if (adjust_shared_perm(idx_tmp_name)) |
| die_errno("unable to make temporary index file readable"); |
| |
| strbuf_addf(name_buffer, "%s.pack", sha1_to_hex(sha1)); |
| |
| if (rename(pack_tmp_name, name_buffer->buf)) |
| die_errno("unable to rename temporary pack file"); |
| |
| strbuf_setlen(name_buffer, basename_len); |
| |
| strbuf_addf(name_buffer, "%s.idx", sha1_to_hex(sha1)); |
| if (rename(idx_tmp_name, name_buffer->buf)) |
| die_errno("unable to rename temporary index file"); |
| |
| strbuf_setlen(name_buffer, basename_len); |
| |
| free((void *)idx_tmp_name); |
| } |