diff options
Diffstat (limited to 'pack-write.c')
| -rw-r--r-- | pack-write.c | 592 |
1 files changed, 592 insertions, 0 deletions
diff --git a/pack-write.c b/pack-write.c new file mode 100644 index 0000000..b19ddf1 --- /dev/null +++ b/pack-write.c @@ -0,0 +1,592 @@ +#include "git-compat-util.h" +#include "environment.h" +#include "gettext.h" +#include "hex.h" +#include "pack.h" +#include "csum-file.h" +#include "remote.h" +#include "chunk-format.h" +#include "pack-mtimes.h" +#include "oidmap.h" +#include "pack-objects.h" +#include "pack-revindex.h" +#include "path.h" +#include "strbuf.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); +} + +/* + * The *sha1 contains the pack content SHA1 hash. + * 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; + 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 = xopen(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600); + } + 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++; + } + hashwrite_be32(f, next - sorted_by_sha); + list = next; + } + + /* + * 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) + hashwrite_be32(f, obj->offset); + hashwrite(f, obj->oid.hash, the_hash_algo->rawsz); + if ((opts->flags & WRITE_IDX_STRICT) && + (i && oideq(&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++; + hashwrite_be32(f, obj->crc32); + } + + /* 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); + hashwrite_be32(f, offset); + } + + /* write the large offset table */ + list = sorted_by_sha; + while (nr_large_offset) { + struct pack_idx_entry *obj = *list++; + uint64_t offset = obj->offset; + + if (!need_large_offset(offset, opts)) + continue; + hashwrite_be64(f, offset); + nr_large_offset--; + } + } + + hashwrite(f, sha1, the_hash_algo->rawsz); + finalize_hashfile(f, NULL, FSYNC_COMPONENT_PACK_METADATA, + CSUM_HASH_IN_STREAM | CSUM_CLOSE | + ((opts->flags & WRITE_IDX_VERIFY) ? 0 : CSUM_FSYNC)); + return index_name; +} + +static int pack_order_cmp(const void *va, const void *vb, void *ctx) +{ + struct pack_idx_entry **objects = ctx; + + off_t oa = objects[*(uint32_t*)va]->offset; + off_t ob = objects[*(uint32_t*)vb]->offset; + + if (oa < ob) + return -1; + if (oa > ob) + return 1; + return 0; +} + +static void write_rev_header(struct hashfile *f) +{ + hashwrite_be32(f, RIDX_SIGNATURE); + hashwrite_be32(f, RIDX_VERSION); + hashwrite_be32(f, oid_version(the_hash_algo)); +} + +static void write_rev_index_positions(struct hashfile *f, + uint32_t *pack_order, + uint32_t nr_objects) +{ + uint32_t i; + for (i = 0; i < nr_objects; i++) + hashwrite_be32(f, pack_order[i]); +} + +static void write_rev_trailer(struct hashfile *f, const unsigned char *hash) +{ + hashwrite(f, hash, the_hash_algo->rawsz); +} + +const char *write_rev_file(const char *rev_name, + struct pack_idx_entry **objects, + uint32_t nr_objects, + const unsigned char *hash, + unsigned flags) +{ + uint32_t *pack_order; + uint32_t i; + const char *ret; + + if (!(flags & WRITE_REV) && !(flags & WRITE_REV_VERIFY)) + return NULL; + + ALLOC_ARRAY(pack_order, nr_objects); + for (i = 0; i < nr_objects; i++) + pack_order[i] = i; + QSORT_S(pack_order, nr_objects, pack_order_cmp, objects); + + ret = write_rev_file_order(rev_name, pack_order, nr_objects, hash, + flags); + + free(pack_order); + + return ret; +} + +const char *write_rev_file_order(const char *rev_name, + uint32_t *pack_order, + uint32_t nr_objects, + const unsigned char *hash, + unsigned flags) +{ + struct hashfile *f; + int fd; + + if ((flags & WRITE_REV) && (flags & WRITE_REV_VERIFY)) + die(_("cannot both write and verify reverse index")); + + if (flags & WRITE_REV) { + if (!rev_name) { + struct strbuf tmp_file = STRBUF_INIT; + fd = odb_mkstemp(&tmp_file, "pack/tmp_rev_XXXXXX"); + rev_name = strbuf_detach(&tmp_file, NULL); + } else { + unlink(rev_name); + fd = xopen(rev_name, O_CREAT|O_EXCL|O_WRONLY, 0600); + } + f = hashfd(fd, rev_name); + } else if (flags & WRITE_REV_VERIFY) { + struct stat statbuf; + if (stat(rev_name, &statbuf)) { + if (errno == ENOENT) { + /* .rev files are optional */ + return NULL; + } else + die_errno(_("could not stat: %s"), rev_name); + } + f = hashfd_check(rev_name); + } else + return NULL; + + write_rev_header(f); + + write_rev_index_positions(f, pack_order, nr_objects); + write_rev_trailer(f, hash); + + if (rev_name && adjust_shared_perm(rev_name) < 0) + die(_("failed to make %s readable"), rev_name); + + finalize_hashfile(f, NULL, FSYNC_COMPONENT_PACK_METADATA, + CSUM_HASH_IN_STREAM | CSUM_CLOSE | + ((flags & WRITE_IDX_VERIFY) ? 0 : CSUM_FSYNC)); + + return rev_name; +} + +static void write_mtimes_header(struct hashfile *f) +{ + hashwrite_be32(f, MTIMES_SIGNATURE); + hashwrite_be32(f, MTIMES_VERSION); + hashwrite_be32(f, oid_version(the_hash_algo)); +} + +/* + * Writes the object mtimes of "objects" for use in a .mtimes file. + * Note that objects must be in lexicographic (index) order, which is + * the expected ordering of these values in the .mtimes file. + */ +static void write_mtimes_objects(struct hashfile *f, + struct packing_data *to_pack, + struct pack_idx_entry **objects, + uint32_t nr_objects) +{ + uint32_t i; + for (i = 0; i < nr_objects; i++) { + struct object_entry *e = (struct object_entry*)objects[i]; + hashwrite_be32(f, oe_cruft_mtime(to_pack, e)); + } +} + +static void write_mtimes_trailer(struct hashfile *f, const unsigned char *hash) +{ + hashwrite(f, hash, the_hash_algo->rawsz); +} + +static char *write_mtimes_file(struct packing_data *to_pack, + struct pack_idx_entry **objects, + uint32_t nr_objects, + const unsigned char *hash) +{ + struct strbuf tmp_file = STRBUF_INIT; + char *mtimes_name; + struct hashfile *f; + int fd; + + if (!to_pack) + BUG("cannot call write_mtimes_file with NULL packing_data"); + + fd = odb_mkstemp(&tmp_file, "pack/tmp_mtimes_XXXXXX"); + mtimes_name = strbuf_detach(&tmp_file, NULL); + f = hashfd(fd, mtimes_name); + + write_mtimes_header(f); + write_mtimes_objects(f, to_pack, objects, nr_objects); + write_mtimes_trailer(f, hash); + + if (adjust_shared_perm(mtimes_name) < 0) + die(_("failed to make %s readable"), mtimes_name); + + finalize_hashfile(f, NULL, FSYNC_COMPONENT_PACK_METADATA, + CSUM_HASH_IN_STREAM | CSUM_CLOSE | CSUM_FSYNC); + + return mtimes_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 (!hasheq(hash, partial_pack_hash)) + 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_component_or_die(FSYNC_COMPONENT_PACK, pack_fd, pack_name); +} + +char *index_pack_lockfile(int ip_out, int *is_well_formed) +{ + 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; + + if (is_well_formed) + *is_well_formed = 1; + packname[len-1] = 0; + if (skip_prefix(packname, "keep\t", &name)) + return xstrfmt("%s/pack/pack-%s.keep", + get_object_directory(), name); + return NULL; + } + if (is_well_formed) + *is_well_formed = 0; + 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); +} + +static void rename_tmp_packfile(struct strbuf *name_prefix, const char *source, + const char *ext) +{ + size_t name_prefix_len = name_prefix->len; + + strbuf_addstr(name_prefix, ext); + if (rename(source, name_prefix->buf)) + die_errno("unable to rename temporary file to '%s'", + name_prefix->buf); + strbuf_setlen(name_prefix, name_prefix_len); +} + +void rename_tmp_packfile_idx(struct strbuf *name_buffer, + char **idx_tmp_name) +{ + rename_tmp_packfile(name_buffer, *idx_tmp_name, "idx"); +} + +void stage_tmp_packfiles(struct strbuf *name_buffer, + const char *pack_tmp_name, + struct pack_idx_entry **written_list, + uint32_t nr_written, + struct packing_data *to_pack, + struct pack_idx_option *pack_idx_opts, + unsigned char hash[], + char **idx_tmp_name) +{ + const char *rev_tmp_name = NULL; + char *mtimes_tmp_name = NULL; + + if (adjust_shared_perm(pack_tmp_name)) + die_errno("unable to make temporary pack file readable"); + + *idx_tmp_name = (char *)write_idx_file(NULL, written_list, nr_written, + pack_idx_opts, hash); + if (adjust_shared_perm(*idx_tmp_name)) + die_errno("unable to make temporary index file readable"); + + rev_tmp_name = write_rev_file(NULL, written_list, nr_written, hash, + pack_idx_opts->flags); + + if (pack_idx_opts->flags & WRITE_MTIMES) { + mtimes_tmp_name = write_mtimes_file(to_pack, written_list, + nr_written, + hash); + } + + rename_tmp_packfile(name_buffer, pack_tmp_name, "pack"); + if (rev_tmp_name) + rename_tmp_packfile(name_buffer, rev_tmp_name, "rev"); + if (mtimes_tmp_name) + rename_tmp_packfile(name_buffer, mtimes_tmp_name, "mtimes"); + + free((char *)rev_tmp_name); + free(mtimes_tmp_name); +} + +void write_promisor_file(const char *promisor_name, struct ref **sought, int nr_sought) +{ + int i, err; + FILE *output = xfopen(promisor_name, "w"); + + for (i = 0; i < nr_sought; i++) + fprintf(output, "%s %s\n", oid_to_hex(&sought[i]->old_oid), + sought[i]->name); + + err = ferror(output); + err |= fclose(output); + if (err) + die(_("could not write '%s' promisor file"), promisor_name); +} |