1 files changed, 62 insertions, 0 deletions
diff --git a/verify_pack.c b/verify_pack.c
new file mode 100644
index 0000000000..da53f35946
--- /dev/null
+++ b/verify_pack.c
@@ -0,0 +1,62 @@
+#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;
+
+	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);
+	return 0;
+}
+
+
+int verify_pack(struct packed_git *p)
+{
+	unsigned long index_size = p->index_size;
+	void *index_base = p->index_base;
+	SHA_CTX ctx;
+	unsigned char sha1[20];
+	int ret;
+
+	/* 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))
+		return error("Packfile index for %s SHA1 mismatch",
+			     p->pack_name);
+
+	/* Verify pack file */
+	use_packed_git(p);
+	ret = verify_packfile(p);
+	unuse_packed_git(p);
+	return ret;
+}