index-pack: use fixup_pack_header_footer()'s validation mode

When completing a thin pack, a new header has to be written to
the pack and a new SHA1 computed.  Make sure that the SHA1 of what
is being read back matches the SHA1 of what was written for both:
the original pack and the appended objects.

To do so, a couple write_or_die() calls were converted to sha1write()
which has the advantage of doing some buffering as well as handling
SHA1 and CRC32 checksum already.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/index-pack.c b/index-pack.c
index 411b80d8150984e96db0775d60e5b8793b07d4a3..a6e91fe3ba47e3b0837648180bb7d47acd3e7dc7 100644 (file)
--- a/index-pack.c
+++ b/index-pack.c
@@ -654,7 +654,7 @@ static void parse_pack_objects(unsigned char *sha1)
        }
 }
 
-static int write_compressed(int fd, void *in, unsigned int size, uint32_t *obj_crc)
+static int write_compressed(struct sha1file *f, void *in, unsigned int size)
 {
        z_stream stream;
        unsigned long maxsize;
@@ -674,13 +674,12 @@ static int write_compressed(int fd, void *in, unsigned int size, uint32_t *obj_c
        deflateEnd(&stream);
 
        size = stream.total_out;
-       write_or_die(fd, out, size);
-       *obj_crc = crc32(*obj_crc, out, size);
+       sha1write(f, out, size);
        free(out);
        return size;
 }
 
-static struct object_entry *append_obj_to_pack(
+static struct object_entry *append_obj_to_pack(struct sha1file *f,
                               const unsigned char *sha1, void *buf,
                               unsigned long size, enum object_type type)
 {
@@ -696,15 +695,15 @@ static struct object_entry *append_obj_to_pack(
                s >>= 7;
        }
        header[n++] = c;
-       write_or_die(output_fd, header, n);
-       obj[0].idx.crc32 = crc32(0, Z_NULL, 0);
-       obj[0].idx.crc32 = crc32(obj[0].idx.crc32, header, n);
+       crc32_begin(f);
+       sha1write(f, header, n);
        obj[0].size = size;
        obj[0].hdr_size = n;
        obj[0].type = type;
        obj[0].real_type = type;
        obj[1].idx.offset = obj[0].idx.offset + n;
-       obj[1].idx.offset += write_compressed(output_fd, buf, size, &obj[0].idx.crc32);
+       obj[1].idx.offset += write_compressed(f, buf, size);
+       obj[0].idx.crc32 = crc32_end(f);
        hashcpy(obj->idx.sha1, sha1);
        return obj;
 }
@@ -716,7 +715,7 @@ static int delta_pos_compare(const void *_a, const void *_b)
        return a->obj_no - b->obj_no;
 }
 
-static void fix_unresolved_deltas(int nr_unresolved)
+static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved)
 {
        struct delta_entry **sorted_by_pos;
        int i, n = 0;
@@ -754,8 +753,8 @@ static void fix_unresolved_deltas(int nr_unresolved)
                if (check_sha1_signature(d->base.sha1, base_obj.data,
                                base_obj.size, typename(type)))
                        die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
-               base_obj.obj = append_obj_to_pack(d->base.sha1, base_obj.data,
-                       base_obj.size, type);
+               base_obj.obj = append_obj_to_pack(f, d->base.sha1,
+                                       base_obj.data, base_obj.size, type);
                link_base_data(NULL, &base_obj);
 
                find_delta_children(&d->base, &first, &last);
@@ -875,7 +874,7 @@ int main(int argc, char **argv)
        const char *keep_name = NULL, *keep_msg = NULL;
        char *index_name_buf = NULL, *keep_name_buf = NULL;
        struct pack_idx_entry **idx_objects;
-       unsigned char sha1[20];
+       unsigned char pack_sha1[20];
        int nongit = 0;
 
        setup_git_directory_gently(&nongit);
@@ -962,13 +961,15 @@ int main(int argc, char **argv)
        parse_pack_header();
        objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
        deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
-       parse_pack_objects(sha1);
+       parse_pack_objects(pack_sha1);
        if (nr_deltas == nr_resolved_deltas) {
                stop_progress(&progress);
                /* Flush remaining pack final 20-byte SHA1. */
                flush();
        } else {
                if (fix_thin_pack) {
+                       struct sha1file *f;
+                       unsigned char read_sha1[20], tail_sha1[20];
                        char msg[48];
                        int nr_unresolved = nr_deltas - nr_resolved_deltas;
                        int nr_objects_initial = nr_objects;
@@ -977,13 +978,19 @@ int main(int argc, char **argv)
                        objects = xrealloc(objects,
                                           (nr_objects + nr_unresolved + 1)
                                           * sizeof(*objects));
-                       fix_unresolved_deltas(nr_unresolved);
+                       f = sha1fd(output_fd, curr_pack);
+                       fix_unresolved_deltas(f, nr_unresolved);
                        sprintf(msg, "completed with %d local objects",
                                nr_objects - nr_objects_initial);
                        stop_progress_msg(&progress, msg);
-                       fixup_pack_header_footer(output_fd, sha1,
+                       sha1close(f, tail_sha1, 0);
+                       hashcpy(read_sha1, pack_sha1);
+                       fixup_pack_header_footer(output_fd, pack_sha1,
                                                 curr_pack, nr_objects,
-                                                NULL, 0);
+                                                read_sha1, consumed_bytes-20);
+                       if (hashcmp(read_sha1, tail_sha1) != 0)
+                               die("Unexpected tail checksum for %s "
+                                   "(disk corruption?)", curr_pack);
                }
                if (nr_deltas != nr_resolved_deltas)
                        die("pack has %d unresolved deltas",
@@ -996,13 +1003,13 @@ int main(int argc, char **argv)
        idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
        for (i = 0; i < nr_objects; i++)
                idx_objects[i] = &objects[i].idx;
-       curr_index = write_idx_file(index_name, idx_objects, nr_objects, sha1);
+       curr_index = write_idx_file(index_name, idx_objects, nr_objects, pack_sha1);
        free(idx_objects);
 
        final(pack_name, curr_pack,
                index_name, curr_index,
                keep_name, keep_msg,
-               sha1);
+               pack_sha1);
        free(objects);
        free(index_name_buf);
        free(keep_name_buf);