1#ifndef PACK_H 2#define PACK_H 3 4#include "object.h" 5 6/* 7 * Packed object header 8 */ 9#define PACK_SIGNATURE 0x5041434b /* "PACK" */ 10#define PACK_VERSION 2 11#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3)) 12struct pack_header { 13 uint32_t hdr_signature; 14 uint32_t hdr_version; 15 uint32_t hdr_entries; 16}; 17 18/* 19 * The first four bytes of index formats later than version 1 should 20 * start with this signature, as all older git binaries would find this 21 * value illegal and abort reading the file. 22 * 23 * This is the case because the number of objects in a packfile 24 * cannot exceed 1,431,660,000 as every object would need at least 25 * 3 bytes of data and the overall packfile cannot exceed 4 GiB with 26 * version 1 of the index file due to the offsets limited to 32 bits. 27 * Clearly the signature exceeds this maximum. 28 * 29 * Very old git binaries will also compare the first 4 bytes to the 30 * next 4 bytes in the index and abort with a "non-monotonic index" 31 * error if the second 4 byte word is smaller than the first 4 32 * byte word. This would be true in the proposed future index 33 * format as idx_signature would be greater than idx_version. 34 */ 35#define PACK_IDX_SIGNATURE 0xff744f63 /* "\377tOc" */ 36 37struct pack_idx_option { 38 unsigned flags; 39 /* flag bits */ 40#define WRITE_IDX_VERIFY 01 41 42 uint32_t version; 43 uint32_t off32_limit; 44 45 /* 46 * List of offsets that would fit within off32_limit but 47 * need to be written out as 64-bit entity for byte-for-byte 48 * verification. 49 */ 50 int anomaly_alloc, anomaly_nr; 51 uint32_t *anomaly; 52}; 53 54extern void reset_pack_idx_option(struct pack_idx_option *); 55 56/* 57 * Packed object index header 58 */ 59struct pack_idx_header { 60 uint32_t idx_signature; 61 uint32_t idx_version; 62}; 63 64/* 65 * Common part of object structure used for write_idx_file 66 */ 67struct pack_idx_entry { 68 unsigned char sha1[20]; 69 uint32_t crc32; 70 off_t offset; 71}; 72 73 74typedef int (*verify_fn)(const unsigned char*, enum object_type, unsigned long, void*, int*); 75 76extern 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); 77extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr); 78extern int verify_pack_index(struct packed_git *); 79extern int verify_pack(struct packed_git *, verify_fn fn); 80extern void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t); 81extern char *index_pack_lockfile(int fd); 82extern int encode_in_pack_object_header(enum object_type, uintmax_t, unsigned char *); 83 84#define PH_ERROR_EOF (-1) 85#define PH_ERROR_PACK_SIGNATURE (-2) 86#define PH_ERROR_PROTOCOL (-3) 87extern int read_pack_header(int fd, struct pack_header *); 88#endif