From 4287307833a7c67b09973fc1023311e473f830b2 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Fri, 16 Mar 2007 16:42:50 -0400 Subject: [PATCH] [PATCH] clean up pack index handling a bit Especially with the new index format to come, it is more appropriate to encapsulate more into check_packed_git_idx() and assume less of the index format in struct packed_git. To that effect, the index_base is renamed to index_data with void * type so it is not used directly but other pointers initialized with it. This allows for a couple pointer cast removal, as well as providing a better generic name to grep for when adding support for new index versions or formats. And index_data is declared const too while at it. Signed-off-by: Nicolas Pitre Signed-off-by: Junio C Hamano --- builtin-pack-objects.c | 14 ++++--- cache.h | 9 +++-- pack-check.c | 8 ++-- pack-redundant.c | 30 ++++++++------- pack.h | 30 +++++++-------- sha1_file.c | 86 +++++++++++++++++++++--------------------- 6 files changed, 90 insertions(+), 87 deletions(-) diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c index f8ebad0b2..73d448b89 100644 --- a/builtin-pack-objects.c +++ b/builtin-pack-objects.c @@ -166,11 +166,12 @@ static void prepare_pack_revindex(struct pack_revindex *rix) struct packed_git *p = rix->p; int num_ent = num_packed_objects(p); int i; - void *index = p->index_base + 256; + const char *index = p->index_data; + index += 4 * 256; rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1)); for (i = 0; i < num_ent; i++) { - unsigned int hl = *((unsigned int *)((char *) index + 24*i)); + uint32_t hl = *((uint32_t *)(index + 24 * i)); rix->revindex[i].offset = ntohl(hl); rix->revindex[i].nr = i; } @@ -217,11 +218,11 @@ static off_t find_packed_object_size(struct packed_git *p, off_t ofs) return entry[1].offset - ofs; } -static unsigned char *find_packed_object_name(struct packed_git *p, - off_t ofs) +static const unsigned char *find_packed_object_name(struct packed_git *p, + off_t ofs) { struct revindex_entry *entry = find_packed_object(p, ofs); - return (unsigned char *)(p->index_base + 256) + 24 * entry->nr + 4; + return ((unsigned char *)p->index_data) + 4 * 256 + 24 * entry->nr + 4; } static void *delta_against(void *buf, unsigned long size, struct object_entry *entry) @@ -996,7 +997,8 @@ static void check_object(struct object_entry *entry) * delta. */ if (!no_reuse_delta) { - unsigned char c, *base_name; + unsigned char c; + const unsigned char *base_name; off_t ofs; unsigned long used_0; /* there is at least 20 bytes left in the pack */ diff --git a/cache.h b/cache.h index a4762eda5..3818e10f8 100644 --- a/cache.h +++ b/cache.h @@ -371,10 +371,11 @@ struct pack_window { extern struct packed_git { struct packed_git *next; struct pack_window *windows; - uint32_t *index_base; - time_t mtime; + const void *index_data; off_t index_size; off_t pack_size; + time_t mtime; + int index_version; int pack_fd; int pack_local; unsigned char sha1[20]; @@ -412,7 +413,7 @@ extern int server_supports(const char *feature); extern struct packed_git *parse_pack_index(unsigned char *sha1); extern struct packed_git *parse_pack_index_file(const unsigned char *sha1, - char *idx_path); + const char *idx_path); extern void prepare_packed_git(void); extern void reprepare_packed_git(void); @@ -424,7 +425,7 @@ extern struct packed_git *find_sha1_pack(const unsigned char *sha1, extern void pack_report(void); extern unsigned char* use_pack(struct packed_git *, struct pack_window **, off_t, unsigned int *); extern void unuse_pack(struct pack_window **); -extern struct packed_git *add_packed_git(char *, int, int); +extern struct packed_git *add_packed_git(const char *, int, int); extern uint32_t num_packed_objects(const struct packed_git *p); extern int nth_packed_object_sha1(const struct packed_git *, uint32_t, unsigned char*); extern off_t find_pack_entry_one(const unsigned char *, struct packed_git *); diff --git a/pack-check.c b/pack-check.c index 299c51412..d9883225e 100644 --- a/pack-check.c +++ b/pack-check.c @@ -5,7 +5,7 @@ static int verify_packfile(struct packed_git *p, struct pack_window **w_curs) { off_t index_size = p->index_size; - void *index_base = p->index_base; + const unsigned char *index_base = p->index_data; SHA_CTX ctx; unsigned char sha1[20]; off_t offset = 0, pack_sig = p->pack_size - 20; @@ -31,7 +31,7 @@ static int verify_packfile(struct packed_git *p, if (hashcmp(sha1, use_pack(p, w_curs, pack_sig, NULL))) return error("Packfile %s SHA1 mismatch with itself", p->pack_name); - if (hashcmp(sha1, (unsigned char *)index_base + index_size - 40)) + if (hashcmp(sha1, index_base + index_size - 40)) return error("Packfile %s SHA1 mismatch with idx", p->pack_name); unuse_pack(w_curs); @@ -127,7 +127,7 @@ static void show_pack_info(struct packed_git *p) int verify_pack(struct packed_git *p, int verbose) { off_t index_size = p->index_size; - void *index_base = p->index_base; + const unsigned char *index_base = p->index_data; SHA_CTX ctx; unsigned char sha1[20]; int ret; @@ -137,7 +137,7 @@ int verify_pack(struct packed_git *p, int verbose) SHA1_Init(&ctx); SHA1_Update(&ctx, index_base, (unsigned int)(index_size - 20)); SHA1_Final(sha1, &ctx); - if (hashcmp(sha1, (unsigned char *)index_base + index_size - 20)) + if (hashcmp(sha1, index_base + index_size - 20)) ret = error("Packfile index for %s SHA1 mismatch", p->pack_name); diff --git a/pack-redundant.c b/pack-redundant.c index c8f7d9af7..40e579b2d 100644 --- a/pack-redundant.c +++ b/pack-redundant.c @@ -17,7 +17,7 @@ static int load_all_packs, verbose, alt_odb; struct llist_item { struct llist_item *next; - unsigned char *sha1; + const unsigned char *sha1; }; static struct llist { struct llist_item *front; @@ -104,9 +104,9 @@ static struct llist * llist_copy(struct llist *list) return ret; } -static inline struct llist_item * llist_insert(struct llist *list, - struct llist_item *after, - unsigned char *sha1) +static inline struct llist_item *llist_insert(struct llist *list, + struct llist_item *after, + const unsigned char *sha1) { struct llist_item *new = llist_item_get(); new->sha1 = sha1; @@ -128,12 +128,14 @@ static inline struct llist_item * llist_insert(struct llist *list, return new; } -static inline struct llist_item *llist_insert_back(struct llist *list, unsigned char *sha1) +static inline struct llist_item *llist_insert_back(struct llist *list, + const unsigned char *sha1) { return llist_insert(list, list->back, sha1); } -static inline struct llist_item *llist_insert_sorted_unique(struct llist *list, unsigned char *sha1, struct llist_item *hint) +static inline struct llist_item *llist_insert_sorted_unique(struct llist *list, + const unsigned char *sha1, struct llist_item *hint) { struct llist_item *prev = NULL, *l; @@ -246,12 +248,12 @@ static struct pack_list * pack_list_difference(const struct pack_list *A, static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2) { int p1_off, p2_off; - unsigned char *p1_base, *p2_base; + const unsigned char *p1_base, *p2_base; struct llist_item *p1_hint = NULL, *p2_hint = NULL; p1_off = p2_off = 256 * 4 + 4; - p1_base = (unsigned char *) p1->pack->index_base; - p2_base = (unsigned char *) p2->pack->index_base; + p1_base = p1->pack->index_data; + p2_base = p2->pack->index_data; while (p1_off <= p1->pack->index_size - 3 * 20 && p2_off <= p2->pack->index_size - 3 * 20) @@ -351,11 +353,11 @@ static size_t sizeof_union(struct packed_git *p1, struct packed_git *p2) { size_t ret = 0; int p1_off, p2_off; - unsigned char *p1_base, *p2_base; + const unsigned char *p1_base, *p2_base; p1_off = p2_off = 256 * 4 + 4; - p1_base = (unsigned char *)p1->index_base; - p2_base = (unsigned char *)p2->index_base; + p1_base = p1->index_data; + p2_base = p2->index_data; while (p1_off <= p1->index_size - 3 * 20 && p2_off <= p2->index_size - 3 * 20) @@ -534,7 +536,7 @@ static struct pack_list * add_pack(struct packed_git *p) { struct pack_list l; size_t off; - unsigned char *base; + const unsigned char *base; if (!p->pack_local && !(alt_odb || verbose)) return NULL; @@ -543,7 +545,7 @@ static struct pack_list * add_pack(struct packed_git *p) llist_init(&l.all_objects); off = 256 * 4 + 4; - base = (unsigned char *)p->index_base; + base = p->index_data; while (off <= p->index_size - 3 * 20) { llist_insert_back(l.all_objects, base + off); off += 24; diff --git a/pack.h b/pack.h index deb427edb..d4d412ccb 100644 --- a/pack.h +++ b/pack.h @@ -16,24 +16,15 @@ struct pack_header { }; /* - * Packed object index header - * - * struct pack_idx_header { - * uint32_t idx_signature; - * uint32_t idx_version; - * }; - * - * Note: this header isn't active yet. In future versions of git - * we may change the index file format. At that time we would start - * the first four bytes of the new index format with this signature, - * as all older git binaries would find this value illegal and abort - * reading the file. + * 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 due - * to the 32 bit offsets used by the index. Clearly the signature - * exceeds this maximum. + * 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" @@ -43,6 +34,15 @@ struct pack_header { */ #define PACK_IDX_SIGNATURE 0xff744f63 /* "\377tOc" */ +/* + * Packed object index header + */ +struct pack_idx_header { + uint32_t idx_signature; + uint32_t idx_version; +}; + + extern int verify_pack(struct packed_git *, int); #define PH_ERROR_EOF (-1) diff --git a/sha1_file.c b/sha1_file.c index 5691448d7..110d69621 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -432,16 +432,15 @@ void pack_report() pack_mapped, peak_pack_mapped); } -static int check_packed_git_idx(const char *path, - unsigned long *idx_size_, - void **idx_map_) +static int check_packed_git_idx(const char *path, struct packed_git *p) { void *idx_map; - uint32_t *index; + struct pack_idx_header *hdr; size_t idx_size; - uint32_t nr, i; + uint32_t nr, i, *index; int fd = open(path, O_RDONLY); struct stat st; + if (fd < 0) return -1; if (fstat(fd, &st)) { @@ -456,15 +455,12 @@ static int check_packed_git_idx(const char *path, idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0); close(fd); - index = idx_map; - *idx_map_ = idx_map; - *idx_size_ = idx_size; - /* a future index format would start with this, as older git * binaries would fail the non-monotonic index check below. * give a nicer warning to the user if we can. */ - if (index[0] == htonl(PACK_IDX_SIGNATURE)) { + hdr = idx_map; + if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) { munmap(idx_map, idx_size); return error("index file %s is a newer version" " and is not supported by this binary" @@ -473,6 +469,7 @@ static int check_packed_git_idx(const char *path, } nr = 0; + index = idx_map; for (i = 0; i < 256; i++) { uint32_t n = ntohl(index[i]); if (n < nr) { @@ -494,6 +491,9 @@ static int check_packed_git_idx(const char *path, return error("wrong index file size in %s", path); } + p->index_version = 1; + p->index_data = idx_map; + p->index_size = idx_size; return 0; } @@ -614,7 +614,7 @@ static int open_packed_git_1(struct packed_git *p) return error("end of packfile %s is unavailable", p->pack_name); if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1)) return error("packfile %s signature is unavailable", p->pack_name); - idx_sha1 = ((unsigned char *)p->index_base) + p->index_size - 40; + idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40; if (hashcmp(sha1, idx_sha1)) return error("packfile %s does not match index", p->pack_name); return 0; @@ -710,38 +710,37 @@ unsigned char* use_pack(struct packed_git *p, return win->base + offset; } -struct packed_git *add_packed_git(char *path, int path_len, int local) +struct packed_git *add_packed_git(const char *path, int path_len, int local) { struct stat st; - struct packed_git *p; - unsigned long idx_size; - void *idx_map; - unsigned char sha1[20]; + struct packed_git *p = xmalloc(sizeof(*p) + path_len + 2); - if (check_packed_git_idx(path, &idx_size, &idx_map)) + /* + * Make sure a corresponding .pack file exists and that + * the index looks sane. + */ + path_len -= strlen(".idx"); + if (path_len < 1) return NULL; - - /* do we have a corresponding .pack file? */ - strcpy(path + path_len - 4, ".pack"); - if (stat(path, &st) || !S_ISREG(st.st_mode)) { - munmap(idx_map, idx_size); + memcpy(p->pack_name, path, path_len); + strcpy(p->pack_name + path_len, ".pack"); + if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode) || + check_packed_git_idx(path, p)) { + free(p); return NULL; } + /* ok, it looks sane as far as we can check without * actually mapping the pack file. */ - p = xmalloc(sizeof(*p) + path_len + 2); - strcpy(p->pack_name, path); - p->index_size = idx_size; p->pack_size = st.st_size; - p->index_base = idx_map; p->next = NULL; p->windows = NULL; p->pack_fd = -1; p->pack_local = local; p->mtime = st.st_mtime; - if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1)) - hashcpy(p->sha1, sha1); + if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1)) + hashclr(p->sha1); return p; } @@ -751,23 +750,19 @@ struct packed_git *parse_pack_index(unsigned char *sha1) return parse_pack_index_file(sha1, path); } -struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path) +struct packed_git *parse_pack_index_file(const unsigned char *sha1, + const char *idx_path) { - struct packed_git *p; - unsigned long idx_size; - void *idx_map; - char *path; + const char *path = sha1_pack_name(sha1); + struct packed_git *p = xmalloc(sizeof(*p) + strlen(path) + 2); - if (check_packed_git_idx(idx_path, &idx_size, &idx_map)) + if (check_packed_git_idx(idx_path, p)) { + free(p); return NULL; + } - path = sha1_pack_name(sha1); - - p = xmalloc(sizeof(*p) + strlen(path) + 2); strcpy(p->pack_name, path); - p->index_size = idx_size; p->pack_size = 0; - p->index_base = idx_map; p->next = NULL; p->windows = NULL; p->pack_fd = -1; @@ -1423,24 +1418,27 @@ uint32_t num_packed_objects(const struct packed_git *p) int nth_packed_object_sha1(const struct packed_git *p, uint32_t n, unsigned char* sha1) { - void *index = p->index_base + 256; + const unsigned char *index = p->index_data; + index += 4 * 256; if (num_packed_objects(p) <= n) return -1; - hashcpy(sha1, (unsigned char *) index + (24 * n) + 4); + hashcpy(sha1, index + 24 * n + 4); return 0; } off_t find_pack_entry_one(const unsigned char *sha1, struct packed_git *p) { - uint32_t *level1_ofs = p->index_base; + const uint32_t *level1_ofs = p->index_data; int hi = ntohl(level1_ofs[*sha1]); int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1])); - void *index = p->index_base + 256; + const unsigned char *index = p->index_data; + + index += 4 * 256; do { int mi = (lo + hi) / 2; - int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1); + int cmp = hashcmp(index + 24 * mi + 4, sha1); if (!cmp) return ntohl(*((uint32_t *)((char *)index + (24 * mi)))); if (cmp > 0) -- 2.26.2