git-commit-vandalism/verify_pack.c
Junio C Hamano f9253394a2 [PATCH] Add git-verify-pack command.
Given a list of <pack>.idx files, this command validates the
index file and the corresponding .pack file for consistency.

This patch also uses the same validation mechanism in fsck-cache
when the --full flag is used.

During normal operation, sha1_file.c verifies that a given .idx
file matches the .pack file by comparing the SHA1 checksum
stored in .idx file and .pack file as a minimum sanity check.
We may further want to check the pack signature and version when
we map the pack, but that would be a separate patch.

Earlier, errors to map a pack file was not flagged fatal but led
to a random fatal error later.  This version explicitly die()s
when such an error is detected.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-29 09:11:39 -07:00

63 lines
1.7 KiB
C

#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;
}