[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>
This commit is contained in:
Junio C Hamano 2005-06-29 02:51:27 -07:00 коммит произвёл Linus Torvalds
Родитель 3c84974207
Коммит f9253394a2
10 изменённых файлов: 231 добавлений и 18 удалений

Просмотреть файл

@ -0,0 +1,38 @@
git-verify-pack(1)
==================
v0.1, June 2005
NAME
----
git-verify-pack - Validate packed GIT archive files.
SYNOPSIS
--------
'git-verify-pack' <pack>.idx ...
DESCRIPTION
-----------
Reads given idx file for packed GIT archive created with
git-pack-objects command and verifies idx file and the
corresponding pack file.
OPTIONS
-------
<pack>.idx ...::
The idx files to verify.
Author
------
Written by Junio C Hamano <junkio@cox.net>
Documentation
--------------
Documentation by Junio C Hamano
GIT
---
Part of the link:git.html[git] suite

Просмотреть файл

@ -110,6 +110,9 @@ link:git-tar-tree.html[git-tar-tree]::
link:git-unpack-file.html[git-unpack-file]::
Creates a temporary file with a blob's contents
link:git-verify-pack.html[git-verify-pack]::
Validates packed GIT archive files
The interrogate commands may create files - and you can force them to
touch the working file set - but in general they don't

Просмотреть файл

@ -36,7 +36,7 @@ PROG= git-update-cache git-diff-files git-init-db git-write-tree \
git-diff-helper git-tar-tree git-local-pull git-write-blob \
git-get-tar-commit-id git-apply git-stripspace \
git-cvs2git git-diff-stages git-rev-parse git-patch-id \
git-pack-objects git-unpack-objects
git-pack-objects git-unpack-objects git-verify-pack
all: $(PROG)
@ -45,7 +45,7 @@ install: $(PROG) $(SCRIPTS)
LIB_OBJS=read-cache.o sha1_file.o usage.o object.o commit.o tree.o blob.o \
tag.o date.o index.o diff-delta.o patch-delta.o entry.o \
epoch.o refs.o csum-file.o
epoch.o refs.o csum-file.o verify_pack.o
LIB_FILE=libgit.a
LIB_H=cache.h object.h blob.h tree.h commit.h tag.h delta.h epoch.h csum-file.h pack.h
@ -124,6 +124,7 @@ git-rev-parse: rev-parse.c
git-patch-id: patch-id.c
git-pack-objects: pack-objects.c
git-unpack-objects: unpack-objects.c
git-verify-pack: verify-pack.c
git-http-pull: LIBS += -lcurl
git-rev-list: LIBS += -lssl

Просмотреть файл

@ -246,9 +246,13 @@ extern struct packed_git {
unsigned int *index_base;
void *pack_base;
unsigned int pack_last_used;
unsigned int pack_use_cnt;
char pack_name[0]; /* something like ".git/objects/pack/xxxxx.pack" */
} *packed_git;
extern void prepare_packed_git(void);
extern int use_packed_git(struct packed_git *);
extern void unuse_packed_git(struct packed_git *);
extern struct packed_git *add_packed_git(char *, int);
extern int num_packed_objects(const struct packed_git *p);
extern int nth_packed_object_sha1(const struct packed_git *, int, unsigned char*);

Просмотреть файл

@ -6,6 +6,7 @@
#include "tree.h"
#include "blob.h"
#include "tag.h"
#include "pack.h"
#define REACHABLE 0x0001
@ -437,6 +438,10 @@ int main(int argc, char **argv)
alt_odb[j].name[-1] = '/';
}
prepare_packed_git();
for (p = packed_git; p; p = p->next)
/* verify gives error messages itself */
verify_pack(p);
for (p = packed_git; p; p = p->next) {
int num = num_packed_objects(p);
for (i = 0; i < num; i++) {

2
pack.h
Просмотреть файл

@ -27,4 +27,6 @@ struct pack_header {
unsigned int hdr_entries;
};
extern int verify_pack(struct packed_git *);
#endif

Просмотреть файл

@ -302,7 +302,7 @@ static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
index = idx_map;
/* check index map */
if (idx_size < 4*256 + 20)
if (idx_size < 4*256 + 20 + 20)
return error("index file too small");
nr = 0;
for (i = 0; i < 256; i++) {
@ -327,12 +327,29 @@ static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
return 0;
}
static void unuse_one_packed_git(void)
static int unuse_one_packed_git(void)
{
/* NOTYET */
struct packed_git *p, *lru = NULL;
for (p = packed_git; p; p = p->next) {
if (p->pack_use_cnt || !p->pack_base)
continue;
if (!lru || p->pack_last_used < lru->pack_last_used)
lru = p;
}
if (!lru)
return 0;
munmap(lru->pack_base, lru->pack_size);
lru->pack_base = NULL;
return 1;
}
static int use_packed_git(struct packed_git *p)
void unuse_packed_git(struct packed_git *p)
{
p->pack_use_cnt--;
}
int use_packed_git(struct packed_git *p)
{
if (!p->pack_base) {
int fd;
@ -340,28 +357,36 @@ static int use_packed_git(struct packed_git *p)
void *map;
pack_mapped += p->pack_size;
while (PACK_MAX_SZ < pack_mapped)
unuse_one_packed_git();
while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
; /* nothing */
fd = open(p->pack_name, O_RDONLY);
if (fd < 0)
return -1;
die("packfile %s cannot be opened", p->pack_name);
if (fstat(fd, &st)) {
close(fd);
return -1;
die("packfile %s cannot be opened", p->pack_name);
}
if (st.st_size != p->pack_size)
return -1;
die("packfile %s size mismatch.", p->pack_name);
map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (map == MAP_FAILED)
return -1;
die("packfile %s cannot be mapped.", p->pack_name);
p->pack_base = map;
/* Check if the pack file matches with the index file.
* this is cheap.
*/
if (memcmp((char*)(p->index_base) + p->index_size - 40,
p->pack_base + p->pack_size - 20, 20))
die("packfile %s does not match index.", p->pack_name);
}
p->pack_last_used = pack_used_ctr++;
p->pack_use_cnt++;
return 0;
}
static struct packed_git *add_packed_git(char *path, int path_len)
struct packed_git *add_packed_git(char *path, int path_len)
{
struct stat st;
struct packed_git *p;
@ -388,6 +413,7 @@ static struct packed_git *add_packed_git(char *path, int path_len)
p->next = NULL;
p->pack_base = NULL;
p->pack_last_used = 0;
p->pack_use_cnt = 0;
return p;
}
@ -671,6 +697,7 @@ static int packed_object_info(struct pack_entry *entry,
unsigned long offset, size, left;
unsigned char *pack;
enum object_type kind;
int retval;
if (use_packed_git(p))
die("cannot map packed file");
@ -681,8 +708,9 @@ static int packed_object_info(struct pack_entry *entry,
switch (kind) {
case OBJ_DELTA:
return packed_delta_info(pack, size, left, type, sizep);
break;
retval = packed_delta_info(pack, size, left, type, sizep);
unuse_packed_git(p);
return retval;
case OBJ_COMMIT:
strcpy(type, "commit");
break;
@ -699,6 +727,7 @@ static int packed_object_info(struct pack_entry *entry,
die("corrupted pack file");
}
*sizep = size;
unuse_packed_git(p);
return 0;
}
@ -785,6 +814,7 @@ static void *unpack_entry(struct pack_entry *entry,
unsigned long offset, size, left;
unsigned char *pack;
enum object_type kind;
void *retval;
if (use_packed_git(p))
die("cannot map packed file");
@ -794,7 +824,9 @@ static void *unpack_entry(struct pack_entry *entry,
left = p->pack_size - offset;
switch (kind) {
case OBJ_DELTA:
return unpack_delta_entry(pack, size, left, type, sizep);
retval = unpack_delta_entry(pack, size, left, type, sizep);
unuse_packed_git(p);
return retval;
case OBJ_COMMIT:
strcpy(type, "commit");
break;
@ -811,12 +843,14 @@ static void *unpack_entry(struct pack_entry *entry,
die("corrupted pack file");
}
*sizep = size;
return unpack_non_delta_entry(pack, size, left);
retval = unpack_non_delta_entry(pack, size, left);
unuse_packed_git(p);
return retval;
}
int num_packed_objects(const struct packed_git *p)
{
/* See check_packed_git_idx and pack-objects.c */
/* See check_packed_git_idx() */
return (p->index_size - 20 - 20 - 4*256) / 24;
}

Просмотреть файл

@ -125,4 +125,42 @@ test_expect_success \
} >current &&
diff expect current'
unset GIT_OBJECT_DIRECTORY
test_expect_success \
'verify pack' \
'git-verify-pack test-1.idx test-2.idx'
test_expect_success \
'corrupt a pack and see if verify catches' \
'cp test-1.idx test-3.idx &&
cp test-2.pack test-3.pack &&
if git-verify-pack test-3.idx
then false
else :;
fi &&
cp test-1.pack test-3.pack &&
dd if=/dev/zero of=test-3.pack count=1 bs=1 conv=notrunc seek=2 &&
if git-verify-pack test-3.idx
then false
else :;
fi &&
cp test-1.pack test-3.pack &&
dd if=/dev/zero of=test-3.pack count=1 bs=1 conv=notrunc seek=7 &&
if git-verify-pack test-3.idx
then false
else :;
fi &&
cp test-1.pack test-3.pack &&
dd if=/dev/zero of=test-3.pack count=1 bs=1 conv=notrunc seek=12 &&
if git-verify-pack test-3.idx
then false
else :;
fi &&
:'
test_done

26
verify-pack.c Normal file
Просмотреть файл

@ -0,0 +1,26 @@
#include "cache.h"
#include "pack.h"
static int verify_one_pack(char *arg)
{
struct packed_git *g = add_packed_git(arg, strlen(arg));
if (!g)
return -1;
return verify_pack(g);
}
int main(int ac, char **av)
{
int errs = 0;
while (1 < ac) {
char path[PATH_MAX];
strcpy(path, av[1]);
if (verify_one_pack(path))
errs++;
else
printf("%s: OK\n", av[1]);
ac--; av++;
}
return !!errs;
}

62
verify_pack.c Normal file
Просмотреть файл

@ -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;
}