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pack: move check_pack_index_ptr(), nth_packed_object_offset()

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Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jonathan Tan 2017-08-18 15:20:32 -07:00 committed by Junio C Hamano
parent d5a1676182
commit 9e0f45f5a6
4 changed files with 49 additions and 49 deletions
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16
cache.h
View File

@ -1620,22 +1620,6 @@ extern int odb_mkstemp(struct strbuf *template, const char *pattern);
*/
extern int odb_pack_keep(const char *name);
/*
* Make sure that a pointer access into an mmap'd index file is within bounds,
* and can provide at least 8 bytes of data.
*
* Note that this is only necessary for variable-length segments of the file
* (like the 64-bit extended offset table), as we compare the size to the
* fixed-length parts when we open the file.
*/
extern void check_pack_index_ptr(const struct packed_git *p, const void *ptr);
/*
* Return the offset of the nth object within the specified packfile.
* The index must already be opened.
*/
extern off_t nth_packed_object_offset(const struct packed_git *, uint32_t n);
/*
* If the object named sha1 is present in the specified packfile,
* return its offset within the packfile; otherwise, return 0.

33
packfile.c
View File

@ -1667,3 +1667,36 @@ const struct object_id *nth_packed_object_oid(struct object_id *oid,
hashcpy(oid->hash, hash);
return oid;
}
void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
{
const unsigned char *ptr = vptr;
const unsigned char *start = p->index_data;
const unsigned char *end = start + p->index_size;
if (ptr < start)
die(_("offset before start of pack index for %s (corrupt index?)"),
p->pack_name);
/* No need to check for underflow; .idx files must be at least 8 bytes */
if (ptr >= end - 8)
die(_("offset beyond end of pack index for %s (truncated index?)"),
p->pack_name);
}
off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
{
const unsigned char *index = p->index_data;
index += 4 * 256;
if (p->index_version == 1) {
return ntohl(*((uint32_t *)(index + 24 * n)));
} else {
uint32_t off;
index += 8 + p->num_objects * (20 + 4);
off = ntohl(*((uint32_t *)(index + 4 * n)));
if (!(off & 0x80000000))
return off;
index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
check_pack_index_ptr(p, index);
return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
ntohl(*((uint32_t *)(index + 4)));
}
}

16
packfile.h
View File

@ -63,6 +63,16 @@ extern void unuse_pack(struct pack_window **);
extern void clear_delta_base_cache(void);
extern struct packed_git *add_packed_git(const char *path, size_t path_len, int local);
/*
* Make sure that a pointer access into an mmap'd index file is within bounds,
* and can provide at least 8 bytes of data.
*
* Note that this is only necessary for variable-length segments of the file
* (like the 64-bit extended offset table), as we compare the size to the
* fixed-length parts when we open the file.
*/
extern void check_pack_index_ptr(const struct packed_git *p, const void *ptr);
/*
* Return the SHA-1 of the nth object within the specified packfile.
* Open the index if it is not already open. The return value points
@ -77,6 +87,11 @@ extern const unsigned char *nth_packed_object_sha1(struct packed_git *, uint32_t
*/
extern const struct object_id *nth_packed_object_oid(struct object_id *, struct packed_git *, uint32_t n);
/*
* Return the offset of the nth object within the specified packfile.
* The index must already be opened.
*/
extern off_t nth_packed_object_offset(const struct packed_git *, uint32_t n);
extern void *unpack_entry(struct packed_git *, off_t, enum object_type *, unsigned long *);
extern unsigned long unpack_object_header_buffer(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep);
@ -94,4 +109,5 @@ extern int packed_object_info(struct packed_git *pack, off_t offset, struct obje
extern void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1);
extern const struct packed_git *has_packed_and_bad(const unsigned char *sha1);
#endif

33
sha1_file.c
View File

@ -1075,39 +1075,6 @@ int parse_sha1_header(const char *hdr, unsigned long *sizep)
return parse_sha1_header_extended(hdr, &oi, 0);
}
void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
{
const unsigned char *ptr = vptr;
const unsigned char *start = p->index_data;
const unsigned char *end = start + p->index_size;
if (ptr < start)
die(_("offset before start of pack index for %s (corrupt index?)"),
p->pack_name);
/* No need to check for underflow; .idx files must be at least 8 bytes */
if (ptr >= end - 8)
die(_("offset beyond end of pack index for %s (truncated index?)"),
p->pack_name);
}
off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
{
const unsigned char *index = p->index_data;
index += 4 * 256;
if (p->index_version == 1) {
return ntohl(*((uint32_t *)(index + 24 * n)));
} else {
uint32_t off;
index += 8 + p->num_objects * (20 + 4);
off = ntohl(*((uint32_t *)(index + 4 * n)));
if (!(off & 0x80000000))
return off;
index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
check_pack_index_ptr(p, index);
return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
ntohl(*((uint32_t *)(index + 4)));
}
}
off_t find_pack_entry_one(const unsigned char *sha1,
struct packed_git *p)
{