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-rw-r--r--pack-write.c592
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);
+}