3c9fc074c2
A pack v2 .idx file usually records offset using 64-bit representation only when the offset does not fit within 31-bit, but you can handcraft your .idx file to record smaller offset using 64-bit, storing all zero in the upper 4-byte. By inspecting the original idx file when running index-pack --verify, encode such low offsets that do not need to be in 64-bit but are encoded using 64-bit just like the original idx file so that we can still validate the pack/idx pair by comparing the idx file recomputed with the original. Signed-off-by: Junio C Hamano <gitster@pobox.com>
86 lines
2.6 KiB
C
86 lines
2.6 KiB
C
#ifndef PACK_H
|
|
#define PACK_H
|
|
|
|
#include "object.h"
|
|
|
|
/*
|
|
* Packed object header
|
|
*/
|
|
#define PACK_SIGNATURE 0x5041434b /* "PACK" */
|
|
#define PACK_VERSION 2
|
|
#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3))
|
|
struct pack_header {
|
|
uint32_t hdr_signature;
|
|
uint32_t hdr_version;
|
|
uint32_t hdr_entries;
|
|
};
|
|
|
|
/*
|
|
* The first four bytes of index formats later than version 1 should
|
|
* start with this signature, as all older git binaries would find this
|
|
* value illegal and abort reading the file.
|
|
*
|
|
* This is the case because the number of objects in a packfile
|
|
* cannot exceed 1,431,660,000 as every object would need at least
|
|
* 3 bytes of data and the overall packfile cannot exceed 4 GiB with
|
|
* version 1 of the index file due to the offsets limited to 32 bits.
|
|
* Clearly the signature exceeds this maximum.
|
|
*
|
|
* Very old git binaries will also compare the first 4 bytes to the
|
|
* next 4 bytes in the index and abort with a "non-monotonic index"
|
|
* error if the second 4 byte word is smaller than the first 4
|
|
* byte word. This would be true in the proposed future index
|
|
* format as idx_signature would be greater than idx_version.
|
|
*/
|
|
#define PACK_IDX_SIGNATURE 0xff744f63 /* "\377tOc" */
|
|
|
|
struct pack_idx_option {
|
|
unsigned flags;
|
|
/* flag bits */
|
|
#define WRITE_IDX_VERIFY 01
|
|
|
|
uint32_t version;
|
|
uint32_t off32_limit;
|
|
|
|
/*
|
|
* List of offsets that would fit within off32_limit but
|
|
* need to be written out as 64-bit entity for byte-for-byte
|
|
* verification.
|
|
*/
|
|
int anomaly_alloc, anomaly_nr;
|
|
uint32_t *anomaly;
|
|
};
|
|
|
|
extern void reset_pack_idx_option(struct pack_idx_option *);
|
|
|
|
/*
|
|
* Packed object index header
|
|
*/
|
|
struct pack_idx_header {
|
|
uint32_t idx_signature;
|
|
uint32_t idx_version;
|
|
};
|
|
|
|
/*
|
|
* Common part of object structure used for write_idx_file
|
|
*/
|
|
struct pack_idx_entry {
|
|
unsigned char sha1[20];
|
|
uint32_t crc32;
|
|
off_t offset;
|
|
};
|
|
|
|
extern const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects, int nr_objects, const struct pack_idx_option *, unsigned char *sha1);
|
|
extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
|
|
extern int verify_pack_index(struct packed_git *);
|
|
extern int verify_pack(struct packed_git *);
|
|
extern void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t);
|
|
extern char *index_pack_lockfile(int fd);
|
|
extern int encode_in_pack_object_header(enum object_type, uintmax_t, unsigned char *);
|
|
|
|
#define PH_ERROR_EOF (-1)
|
|
#define PH_ERROR_PACK_SIGNATURE (-2)
|
|
#define PH_ERROR_PROTOCOL (-3)
|
|
extern int read_pack_header(int fd, struct pack_header *);
|
|
#endif
|