[PATCH] verify-pack updates.

Nico pointed out that having verify_pack.c and verify-pack.c was
confusing.  Rename verify_pack.c to pack-check.c as suggested,
and enhances the verification done quite a bit.

 - Built-in sha1_file unpacking knows that a base object of a
   deltified object _must_ be in the same pack, and takes
   advantage of that fact.

 - Earlier verify-pack command only checked the SHA1 sum for the
   entire pack file and did not look into its contents.  It now
   checks everything idx file claims to have unpacks correctly.

 - It now has a hook to give more detailed information for
   objects contained in the pack under -v flag.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 112 insertions, 0 deletions

diff --git a/pack-check.c b/pack-check.c
new file mode 100644
index 0000000000..9c723972b7
--- /dev/null
+++ b/pack-check.c
@@ -0,0 +1,112 @@
+#include "cache.h"
+#include "pack.h"
+
+static int verify_packfile(struct packed_git *p)
+{
+	unsigned long index_size = p->index_size;
+	void *index_base = p->index_base;
+	SHA_CTX ctx;
+	unsigned char sha1[20];
+	unsigned long pack_size = p->pack_size;
+	void *pack_base;
+	struct pack_header *hdr;
+	int nr_objects, err, i;
+
+	/* Header consistency check */
+	hdr = p->pack_base;
+	if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
+		return error("Packfile signature mismatch", p->pack_name);
+	if (hdr->hdr_version != htonl(PACK_VERSION))
+		return error("Packfile version %d different from ours %d",
+			     ntohl(hdr->hdr_version), PACK_VERSION);
+	nr_objects = ntohl(hdr->hdr_entries);
+	if (num_packed_objects(p) != nr_objects)
+		return error("Packfile claims to have %d objects, "
+			     "while idx size expects %d", nr_objects,
+			     num_packed_objects(p));
+
+	SHA1_Init(&ctx);
+	pack_base = p->pack_base;
+	SHA1_Update(&ctx, pack_base, pack_size - 20);
+	SHA1_Final(sha1, &ctx);
+	if (memcmp(sha1, index_base + index_size - 40, 20))
+		return error("Packfile %s SHA1 mismatch with idx",
+			     p->pack_name);
+	if (memcmp(sha1, pack_base + pack_size - 20, 20))
+		return error("Packfile %s SHA1 mismatch with itself",
+			     p->pack_name);
+
+	/* Make sure everything reachable from idx is valid.  Since we
+	 * have verified that nr_objects matches between idx and pack,
+	 * we do not do scan-streaming check on the pack file.
+	 */
+	for (i = err = 0; i < nr_objects; i++) {
+		unsigned char sha1[20];
+		struct pack_entry e;
+		void *data;
+		char type[20];
+		unsigned long size;
+
+		if (nth_packed_object_sha1(p, i, sha1))
+			die("internal error pack-check nth-packed-object");
+		if (!find_pack_entry_one(sha1, &e, p))
+			die("internal error pack-check find-pack-entry-one");
+		data = unpack_entry_gently(&e, type, &size);
+		if (!data) {
+			err = error("cannot unpack %s from %s",
+				    sha1_to_hex(sha1), p->pack_name);
+			continue;
+		}
+		if (check_sha1_signature(sha1, data, size, type)) {
+			err = error("cannot packed %s from %s corrupt",
+				    sha1_to_hex(sha1), p->pack_name);
+			free(data);
+			continue;
+		}
+		free(data);
+	}
+
+	return err;
+}
+
+
+static void show_pack_info(struct packed_git *p)
+{
+	/* Next round */
+}
+
+int verify_pack(struct packed_git *p, int verbose)
+{
+	unsigned long index_size = p->index_size;
+	void *index_base = p->index_base;
+	SHA_CTX ctx;
+	unsigned char sha1[20];
+	int ret;
+
+	ret = 0;
+	/* Verify SHA1 sum of the index file */
+	SHA1_Init(&ctx);
+	SHA1_Update(&ctx, index_base, index_size - 20);
+	SHA1_Final(sha1, &ctx);
+	if (memcmp(sha1, index_base + index_size - 20, 20))
+		ret = error("Packfile index for %s SHA1 mismatch",
+			    p->pack_name);
+
+	if (!ret) {
+		/* Verify pack file */
+		use_packed_git(p);
+		ret = verify_packfile(p);
+		unuse_packed_git(p);
+	}
+
+	if (verbose) {
+		if (ret)
+			printf("%s: bad\n", p->pack_name);
+		else {
+			show_pack_info(p);
+			printf("%s: ok\n", p->pack_name);
+		}
+	}
+
+	return ret;
+}