[PATCH v3 15/23] pack: move clear_delta_base_cache(), packed_object_info(), unpack_entry()
- From
- Jonathan Tan <jonathantanmy@google.com>
- Date
- Aug 18, 2017, 22:20 UTC
- Message-ID
- <373a454c29c6f37d4741fe4868b27089e283d522.1503094448.git.jonathantanmy@google.com>
- In-Reply-To
- <cover.1503094448.git.jonathantanmy@google.com>
Both sha1_file.c and packfile.c now need read_object(), so a copy of read_object() was created in packfile.c.
This patch makes both mark_bad_packed_object() and has_packed_and_bad() global. Unlike most of the other patches in this series, these 2 functions need to remain global.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> --- cache.h | 7 - packfile.c | 661 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ packfile.h | 10 + sha1_file.c | 677 ++---------------------------------------------------------- 4 files changed, 685 insertions(+), 670 deletions(-)
diff --git a/cache.h b/cache.h index 7adbc587d..11aa18e6a 100644 --- a/cache.h +++ b/cache.h @@ -1194,9 +1194,6 @@ extern void *map_sha1_file(const unsigned char *sha1, unsigned long *size); extern int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz); extern int parse_sha1_header(const char *hdr, unsigned long *sizep); -/* global flag to enable extra checks when accessing packed objects */ -extern int do_check_packed_object_crc; - extern int check_sha1_signature(const unsigned char *sha1, void *buf, unsigned long size, const char *type); extern int finalize_object_file(const char *tmpfile, const char *filename); @@ -1629,8 +1626,6 @@ extern int odb_mkstemp(struct strbuf *template, const char *pattern); */ extern int odb_pack_keep(const char *name); -extern void clear_delta_base_cache(void); - /* * Make sure that a pointer access into an mmap'd index file is within bounds, * and can provide at least 8 bytes of data. @@ -1668,7 +1663,6 @@ extern off_t nth_packed_object_offset(const struct packed_git *, uint32_t n); extern off_t find_pack_entry_one(const unsigned char *sha1, struct packed_git *); extern int is_pack_valid(struct packed_git *); -extern void *unpack_entry(struct packed_git *, off_t, enum object_type *, unsigned long *); /* * Iterate over the files in the loose-object parts of the object @@ -1779,7 +1773,6 @@ struct object_info { /* Do not retry packed storage after checking packed and loose storage */ #define OBJECT_INFO_QUICK 8 extern int sha1_object_info_extended(const unsigned char *, struct object_info *, unsigned flags); -extern int packed_object_info(struct packed_git *pack, off_t offset, struct object_info *); /* Dumb servers support */ extern int update_server_info(int); diff --git a/packfile.c b/packfile.c index 3543b37b8..624cc109e 100644 --- a/packfile.c +++ b/packfile.c @@ -5,6 +5,8 @@ #include "mergesort.h" #include "packfile.h" #include "delta.h" +#include "list.h" +#include "streaming.h" char *odb_pack_name(struct strbuf *buf, const unsigned char *sha1, @@ -975,3 +977,662 @@ int unpack_object_header(struct packed_git *p, return type; } + +void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1) +{ + unsigned i; + for (i = 0; i < p->num_bad_objects; i++) + if (!hashcmp(sha1, p->bad_object_sha1 + GIT_SHA1_RAWSZ * i)) + return; + p->bad_object_sha1 = xrealloc(p->bad_object_sha1, + st_mult(GIT_MAX_RAWSZ, + st_add(p->num_bad_objects, 1))); + hashcpy(p->bad_object_sha1 + GIT_SHA1_RAWSZ * p->num_bad_objects, sha1); + p->num_bad_objects++; +} + +const struct packed_git *has_packed_and_bad(const unsigned char *sha1) +{ + struct packed_git *p; + unsigned i; + + for (p = packed_git; p; p = p->next) + for (i = 0; i < p->num_bad_objects; i++) + if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i)) + return p; + return NULL; +} + +static off_t get_delta_base(struct packed_git *p, + struct pack_window **w_curs, + off_t *curpos, + enum object_type type, + off_t delta_obj_offset) +{ + unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL); + off_t base_offset; + + /* use_pack() assured us we have [base_info, base_info + 20) + * as a range that we can look at without walking off the + * end of the mapped window. Its actually the hash size + * that is assured. An OFS_DELTA longer than the hash size + * is stupid, as then a REF_DELTA would be smaller to store. + */ + if (type == OBJ_OFS_DELTA) { + unsigned used = 0; + unsigned char c = base_info[used++]; + base_offset = c & 127; + while (c & 128) { + base_offset += 1; + if (!base_offset || MSB(base_offset, 7)) + return 0; /* overflow */ + c = base_info[used++]; + base_offset = (base_offset << 7) + (c & 127); + } + base_offset = delta_obj_offset - base_offset; + if (base_offset <= 0 || base_offset >= delta_obj_offset) + return 0; /* out of bound */ + *curpos += used; + } else if (type == OBJ_REF_DELTA) { + /* The base entry _must_ be in the same pack */ + base_offset = find_pack_entry_one(base_info, p); + *curpos += 20; + } else + die("I am totally screwed"); + return base_offset; +} + +/* + * Like get_delta_base above, but we return the sha1 instead of the pack + * offset. This means it is cheaper for REF deltas (we do not have to do + * the final object lookup), but more expensive for OFS deltas (we + * have to load the revidx to convert the offset back into a sha1). + */ +static const unsigned char *get_delta_base_sha1(struct packed_git *p, + struct pack_window **w_curs, + off_t curpos, + enum object_type type, + off_t delta_obj_offset) +{ + if (type == OBJ_REF_DELTA) { + unsigned char *base = use_pack(p, w_curs, curpos, NULL); + return base; + } else if (type == OBJ_OFS_DELTA) { + struct revindex_entry *revidx; + off_t base_offset = get_delta_base(p, w_curs, &curpos, + type, delta_obj_offset); + + if (!base_offset) + return NULL; + + revidx = find_pack_revindex(p, base_offset); + if (!revidx) + return NULL; + + return nth_packed_object_sha1(p, revidx->nr); + } else + return NULL; +} + +static int retry_bad_packed_offset(struct packed_git *p, off_t obj_offset) +{ + int type; + struct revindex_entry *revidx; + const unsigned char *sha1; + revidx = find_pack_revindex(p, obj_offset); + if (!revidx) + return OBJ_BAD; + sha1 = nth_packed_object_sha1(p, revidx->nr); + mark_bad_packed_object(p, sha1); + type = sha1_object_info(sha1, NULL); + if (type <= OBJ_NONE) + return OBJ_BAD; + return type; +} + +#define POI_STACK_PREALLOC 64 + +static enum object_type packed_to_object_type(struct packed_git *p, + off_t obj_offset, + enum object_type type, + struct pack_window **w_curs, + off_t curpos) +{ + off_t small_poi_stack[POI_STACK_PREALLOC]; + off_t *poi_stack = small_poi_stack; + int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC; + + while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) { + off_t base_offset; + unsigned long size; + /* Push the object we're going to leave behind */ + if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) { + poi_stack_alloc = alloc_nr(poi_stack_nr); + ALLOC_ARRAY(poi_stack, poi_stack_alloc); + memcpy(poi_stack, small_poi_stack, sizeof(off_t)*poi_stack_nr); + } else { + ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc); + } + poi_stack[poi_stack_nr++] = obj_offset; + /* If parsing the base offset fails, just unwind */ + base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset); + if (!base_offset) + goto unwind; + curpos = obj_offset = base_offset; + type = unpack_object_header(p, w_curs, &curpos, &size); + if (type <= OBJ_NONE) { + /* If getting the base itself fails, we first + * retry the base, otherwise unwind */ + type = retry_bad_packed_offset(p, base_offset); + if (type > OBJ_NONE) + goto out; + goto unwind; + } + } + + switch (type) { + case OBJ_BAD: + case OBJ_COMMIT: + case OBJ_TREE: + case OBJ_BLOB: + case OBJ_TAG: + break; + default: + error("unknown object type %i at offset %"PRIuMAX" in %s", + type, (uintmax_t)obj_offset, p->pack_name); + type = OBJ_BAD; + } + +out: + if (poi_stack != small_poi_stack) + free(poi_stack); + return type; + +unwind: + while (poi_stack_nr) { + obj_offset = poi_stack[--poi_stack_nr]; + type = retry_bad_packed_offset(p, obj_offset); + if (type > OBJ_NONE) + goto out; + } + type = OBJ_BAD; + goto out; +} + +static struct hashmap delta_base_cache; +static size_t delta_base_cached; + +static LIST_HEAD(delta_base_cache_lru); + +struct delta_base_cache_key { + struct packed_git *p; + off_t base_offset; +}; + +struct delta_base_cache_entry { + struct hashmap hash; + struct delta_base_cache_key key; + struct list_head lru; + void *data; + unsigned long size; + enum object_type type; +}; + +static unsigned int pack_entry_hash(struct packed_git *p, off_t base_offset) +{ + unsigned int hash; + + hash = (unsigned int)(intptr_t)p + (unsigned int)base_offset; + hash += (hash >> 8) + (hash >> 16); + return hash; +} + +static struct delta_base_cache_entry * +get_delta_base_cache_entry(struct packed_git *p, off_t base_offset) +{ + struct hashmap_entry entry; + struct delta_base_cache_key key; + + if (!delta_base_cache.cmpfn) + return NULL; + + hashmap_entry_init(&entry, pack_entry_hash(p, base_offset)); + key.p = p; + key.base_offset = base_offset; + return hashmap_get(&delta_base_cache, &entry, &key); +} + +static int delta_base_cache_key_eq(const struct delta_base_cache_key *a, + const struct delta_base_cache_key *b) +{ + return a->p == b->p && a->base_offset == b->base_offset; +} + +static int delta_base_cache_hash_cmp(const void *unused_cmp_data, + const void *va, const void *vb, + const void *vkey) +{ + const struct delta_base_cache_entry *a = va, *b = vb; + const struct delta_base_cache_key *key = vkey; + if (key) + return !delta_base_cache_key_eq(&a->key, key); + else + return !delta_base_cache_key_eq(&a->key, &b->key); +} + +static int in_delta_base_cache(struct packed_git *p, off_t base_offset) +{ + return !!get_delta_base_cache_entry(p, base_offset); +} + +/* + * Remove the entry from the cache, but do _not_ free the associated + * entry data. The caller takes ownership of the "data" buffer, and + * should copy out any fields it wants before detaching. + */ +static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent) +{ + hashmap_remove(&delta_base_cache, ent, &ent->key); + list_del(&ent->lru); + delta_base_cached -= ent->size; + free(ent); +} + +static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset, + unsigned long *base_size, enum object_type *type) +{ + struct delta_base_cache_entry *ent; + + ent = get_delta_base_cache_entry(p, base_offset); + if (!ent) + return unpack_entry(p, base_offset, type, base_size); + + if (type) + *type = ent->type; + if (base_size) + *base_size = ent->size; + return xmemdupz(ent->data, ent->size); +} + +static inline void release_delta_base_cache(struct delta_base_cache_entry *ent) +{ + free(ent->data); + detach_delta_base_cache_entry(ent); +} + +void clear_delta_base_cache(void) +{ + struct list_head *lru, *tmp; + list_for_each_safe(lru, tmp, &delta_base_cache_lru) { + struct delta_base_cache_entry *entry = + list_entry(lru, struct delta_base_cache_entry, lru); + release_delta_base_cache(entry); + } +} + +static void add_delta_base_cache(struct packed_git *p, off_t base_offset, + void *base, unsigned long base_size, enum object_type type) +{ + struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent)); + struct list_head *lru, *tmp; + + delta_base_cached += base_size; + + list_for_each_safe(lru, tmp, &delta_base_cache_lru) { + struct delta_base_cache_entry *f = + list_entry(lru, struct delta_base_cache_entry, lru); + if (delta_base_cached <= delta_base_cache_limit) + break; + release_delta_base_cache(f); + } + + ent->key.p = p; + ent->key.base_offset = base_offset; + ent->type = type; + ent->data = base; + ent->size = base_size; + list_add_tail(&ent->lru, &delta_base_cache_lru); + + if (!delta_base_cache.cmpfn) + hashmap_init(&delta_base_cache, delta_base_cache_hash_cmp, NULL, 0); + hashmap_entry_init(ent, pack_entry_hash(p, base_offset)); + hashmap_add(&delta_base_cache, ent); +} + +int packed_object_info(struct packed_git *p, off_t obj_offset, + struct object_info *oi) +{ + struct pack_window *w_curs = NULL; + unsigned long size; + off_t curpos = obj_offset; + enum object_type type; + + /* + * We always get the representation type, but only convert it to + * a "real" type later if the caller is interested. + */ + if (oi->contentp) { + *oi->contentp = cache_or_unpack_entry(p, obj_offset, oi->sizep, + &type); + if (!*oi->contentp) + type = OBJ_BAD; + } else { + type = unpack_object_header(p, &w_curs, &curpos, &size); + } + + if (!oi->contentp && oi->sizep) { + if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) { + off_t tmp_pos = curpos; + off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos, + type, obj_offset); + if (!base_offset) { + type = OBJ_BAD; + goto out; + } + *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos); + if (*oi->sizep == 0) { + type = OBJ_BAD; + goto out; + } + } else { + *oi->sizep = size; + } + } + + if (oi->disk_sizep) { + struct revindex_entry *revidx = find_pack_revindex(p, obj_offset); + *oi->disk_sizep = revidx[1].offset - obj_offset; + } + + if (oi->typep || oi->typename) { + enum object_type ptot; + ptot = packed_to_object_type(p, obj_offset, type, &w_curs, + curpos); + if (oi->typep) + *oi->typep = ptot; + if (oi->typename) { + const char *tn = typename(ptot); + if (tn) + strbuf_addstr(oi->typename, tn); + } + if (ptot < 0) { + type = OBJ_BAD; + goto out; + } + } + + if (oi->delta_base_sha1) { + if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) { + const unsigned char *base; + + base = get_delta_base_sha1(p, &w_curs, curpos, + type, obj_offset); + if (!base) { + type = OBJ_BAD; + goto out; + } + + hashcpy(oi->delta_base_sha1, base); + } else + hashclr(oi->delta_base_sha1); + } + + oi->whence = in_delta_base_cache(p, obj_offset) ? OI_DBCACHED : + OI_PACKED; + +out: + unuse_pack(&w_curs); + return type; +} + +static void *unpack_compressed_entry(struct packed_git *p, + struct pack_window **w_curs, + off_t curpos, + unsigned long size) +{ + int st; + git_zstream stream; + unsigned char *buffer, *in; + + buffer = xmallocz_gently(size); + if (!buffer) + return NULL; + memset(&stream, 0, sizeof(stream)); + stream.next_out = buffer; + stream.avail_out = size + 1; + + git_inflate_init(&stream); + do { + in = use_pack(p, w_curs, curpos, &stream.avail_in); + stream.next_in = in; + st = git_inflate(&stream, Z_FINISH); + if (!stream.avail_out) + break; /* the payload is larger than it should be */ + curpos += stream.next_in - in; + } while (st == Z_OK || st == Z_BUF_ERROR); + git_inflate_end(&stream); + if ((st != Z_STREAM_END) || stream.total_out != size) { + free(buffer); + return NULL; + } + + return buffer; +} + +static void write_pack_access_log(struct packed_git *p, off_t obj_offset) +{ + static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS); + trace_printf_key(&pack_access, "%s %"PRIuMAX"\n", + p->pack_name, (uintmax_t)obj_offset); +} + +int do_check_packed_object_crc; + +#define UNPACK_ENTRY_STACK_PREALLOC 64 +struct unpack_entry_stack_ent { + off_t obj_offset; + off_t curpos; + unsigned long size; +}; + +static void *read_object(const unsigned char *sha1, enum object_type *type, + unsigned long *size) +{ + struct object_info oi = OBJECT_INFO_INIT; + void *content; + oi.typep = type; + oi.sizep = size; + oi.contentp = &content; + + if (sha1_object_info_extended(sha1, &oi, 0) < 0) + return NULL; + return content; +} + +void *unpack_entry(struct packed_git *p, off_t obj_offset, + enum object_type *final_type, unsigned long *final_size) +{ + struct pack_window *w_curs = NULL; + off_t curpos = obj_offset; + void *data = NULL; + unsigned long size; + enum object_type type; + struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC]; + struct unpack_entry_stack_ent *delta_stack = small_delta_stack; + int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC; + int base_from_cache = 0; + + write_pack_access_log(p, obj_offset); + + /* PHASE 1: drill down to the innermost base object */ + for (;;) { + off_t base_offset; + int i; + struct delta_base_cache_entry *ent; + + ent = get_delta_base_cache_entry(p, curpos); + if (ent) { + type = ent->type; + data = ent->data; + size = ent->size; + detach_delta_base_cache_entry(ent); + base_from_cache = 1; + break; + } + + if (do_check_packed_object_crc && p->index_version > 1) { + struct revindex_entry *revidx = find_pack_revindex(p, obj_offset); + off_t len = revidx[1].offset - obj_offset; + if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) { + const unsigned char *sha1 = + nth_packed_object_sha1(p, revidx->nr); + error("bad packed object CRC for %s", + sha1_to_hex(sha1)); + mark_bad_packed_object(p, sha1); + data = NULL; + goto out; + } + } + + type = unpack_object_header(p, &w_curs, &curpos, &size); + if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA) + break; + + base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset); + if (!base_offset) { + error("failed to validate delta base reference " + "at offset %"PRIuMAX" from %s", + (uintmax_t)curpos, p->pack_name); + /* bail to phase 2, in hopes of recovery */ + data = NULL; + break; + } + + /* push object, proceed to base */ + if (delta_stack_nr >= delta_stack_alloc + && delta_stack == small_delta_stack) { + delta_stack_alloc = alloc_nr(delta_stack_nr); + ALLOC_ARRAY(delta_stack, delta_stack_alloc); + memcpy(delta_stack, small_delta_stack, + sizeof(*delta_stack)*delta_stack_nr); + } else { + ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc); + } + i = delta_stack_nr++; + delta_stack[i].obj_offset = obj_offset; + delta_stack[i].curpos = curpos; + delta_stack[i].size = size; + + curpos = obj_offset = base_offset; + } + + /* PHASE 2: handle the base */ + switch (type) { + case OBJ_OFS_DELTA: + case OBJ_REF_DELTA: + if (data) + die("BUG: unpack_entry: left loop at a valid delta"); + break; + case OBJ_COMMIT: + case OBJ_TREE: + case OBJ_BLOB: + case OBJ_TAG: + if (!base_from_cache) + data = unpack_compressed_entry(p, &w_curs, curpos, size); + break; + default: + data = NULL; + error("unknown object type %i at offset %"PRIuMAX" in %s", + type, (uintmax_t)obj_offset, p->pack_name); + } + + /* PHASE 3: apply deltas in order */ + + /* invariants: + * 'data' holds the base data, or NULL if there was corruption + */ + while (delta_stack_nr) { + void *delta_data; + void *base = data; + void *external_base = NULL; + unsigned long delta_size, base_size = size; + int i; + + data = NULL; + + if (base) + add_delta_base_cache(p, obj_offset, base, base_size, type); + + if (!base) { + /* + * We're probably in deep shit, but let's try to fetch + * the required base anyway from another pack or loose. + * This is costly but should happen only in the presence + * of a corrupted pack, and is better than failing outright. + */ + struct revindex_entry *revidx; + const unsigned char *base_sha1; + revidx = find_pack_revindex(p, obj_offset); + if (revidx) { + base_sha1 = nth_packed_object_sha1(p, revidx->nr); + error("failed to read delta base object %s" + " at offset %"PRIuMAX" from %s", + sha1_to_hex(base_sha1), (uintmax_t)obj_offset, + p->pack_name); + mark_bad_packed_object(p, base_sha1); + base = read_object(base_sha1, &type, &base_size); + external_base = base; + } + } + + i = --delta_stack_nr; + obj_offset = delta_stack[i].obj_offset; + curpos = delta_stack[i].curpos; + delta_size = delta_stack[i].size; + + if (!base) + continue; + + delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size); + + if (!delta_data) { + error("failed to unpack compressed delta " + "at offset %"PRIuMAX" from %s", + (uintmax_t)curpos, p->pack_name); + data = NULL; + free(external_base); + continue; + } + + data = patch_delta(base, base_size, + delta_data, delta_size, + &size); + + /* + * We could not apply the delta; warn the user, but keep going. + * Our failure will be noticed either in the next iteration of + * the loop, or if this is the final delta, in the caller when + * we return NULL. Those code paths will take care of making + * a more explicit warning and retrying with another copy of + * the object. + */ + if (!data) + error("failed to apply delta"); + + free(delta_data); + free(external_base); + } + + if (final_type) + *final_type = type; + if (final_size) + *final_size = size; + +out: + unuse_pack(&w_curs); + + if (delta_stack != small_delta_stack) + free(delta_stack); + + return data; +} diff --git a/packfile.h b/packfile.h index d22a528b5..c28eaccc6 100644 --- a/packfile.h +++ b/packfile.h @@ -60,8 +60,10 @@ extern unsigned char *use_pack(struct packed_git *, struct pack_window **, off_t extern void close_pack_windows(struct packed_git *); extern void close_all_packs(void); 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); +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); extern unsigned long get_size_from_delta(struct packed_git *, struct pack_window **, off_t); extern int unpack_object_header(struct packed_git *, struct pack_window **, off_t *, unsigned long *); @@ -70,4 +72,12 @@ extern void release_pack_memory(size_t); extern int open_packed_git(struct packed_git *p); +/* global flag to enable extra checks when accessing packed objects */ +extern int do_check_packed_object_crc; + +extern int packed_object_info(struct packed_git *pack, off_t offset, struct object_info *); + +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 diff --git a/sha1_file.c b/sha1_file.c index 681dcf1c0..e537ba089 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -718,32 +718,6 @@ void *xmmap(void *start, size_t length, return ret; } -static void mark_bad_packed_object(struct packed_git *p, - const unsigned char *sha1) -{ - unsigned i; - for (i = 0; i < p->num_bad_objects; i++) - if (!hashcmp(sha1, p->bad_object_sha1 + GIT_SHA1_RAWSZ * i)) - return; - p->bad_object_sha1 = xrealloc(p->bad_object_sha1, - st_mult(GIT_MAX_RAWSZ, - st_add(p->num_bad_objects, 1))); - hashcpy(p->bad_object_sha1 + GIT_SHA1_RAWSZ * p->num_bad_objects, sha1); - p->num_bad_objects++; -} - -static const struct packed_git *has_packed_and_bad(const unsigned char *sha1) -{ - struct packed_git *p; - unsigned i; - - for (p = packed_git; p; p = p->next) - for (i = 0; i < p->num_bad_objects; i++) - if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i)) - return p; - return NULL; -} - /* * With an in-core object data in "map", rehash it to make sure the * object name actually matches "sha1" to detect object corruption. @@ -1100,629 +1074,6 @@ int parse_sha1_header(const char *hdr, unsigned long *sizep) return parse_sha1_header_extended(hdr, &oi, 0); } -static off_t get_delta_base(struct packed_git *p, - struct pack_window **w_curs, - off_t *curpos, - enum object_type type, - off_t delta_obj_offset) -{ - unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL); - off_t base_offset; - - /* use_pack() assured us we have [base_info, base_info + 20) - * as a range that we can look at without walking off the - * end of the mapped window. Its actually the hash size - * that is assured. An OFS_DELTA longer than the hash size - * is stupid, as then a REF_DELTA would be smaller to store. - */ - if (type == OBJ_OFS_DELTA) { - unsigned used = 0; - unsigned char c = base_info[used++]; - base_offset = c & 127; - while (c & 128) { - base_offset += 1; - if (!base_offset || MSB(base_offset, 7)) - return 0; /* overflow */ - c = base_info[used++]; - base_offset = (base_offset << 7) + (c & 127); - } - base_offset = delta_obj_offset - base_offset; - if (base_offset <= 0 || base_offset >= delta_obj_offset) - return 0; /* out of bound */ - *curpos += used; - } else if (type == OBJ_REF_DELTA) { - /* The base entry _must_ be in the same pack */ - base_offset = find_pack_entry_one(base_info, p); - *curpos += 20; - } else - die("I am totally screwed"); - return base_offset; -} - -/* - * Like get_delta_base above, but we return the sha1 instead of the pack - * offset. This means it is cheaper for REF deltas (we do not have to do - * the final object lookup), but more expensive for OFS deltas (we - * have to load the revidx to convert the offset back into a sha1). - */ -static const unsigned char *get_delta_base_sha1(struct packed_git *p, - struct pack_window **w_curs, - off_t curpos, - enum object_type type, - off_t delta_obj_offset) -{ - if (type == OBJ_REF_DELTA) { - unsigned char *base = use_pack(p, w_curs, curpos, NULL); - return base; - } else if (type == OBJ_OFS_DELTA) { - struct revindex_entry *revidx; - off_t base_offset = get_delta_base(p, w_curs, &curpos, - type, delta_obj_offset); - - if (!base_offset) - return NULL; - - revidx = find_pack_revindex(p, base_offset); - if (!revidx) - return NULL; - - return nth_packed_object_sha1(p, revidx->nr); - } else - return NULL; -} - -static int retry_bad_packed_offset(struct packed_git *p, off_t obj_offset) -{ - int type; - struct revindex_entry *revidx; - const unsigned char *sha1; - revidx = find_pack_revindex(p, obj_offset); - if (!revidx) - return OBJ_BAD; - sha1 = nth_packed_object_sha1(p, revidx->nr); - mark_bad_packed_object(p, sha1); - type = sha1_object_info(sha1, NULL); - if (type <= OBJ_NONE) - return OBJ_BAD; - return type; -} - -#define POI_STACK_PREALLOC 64 - -static enum object_type packed_to_object_type(struct packed_git *p, - off_t obj_offset, - enum object_type type, - struct pack_window **w_curs, - off_t curpos) -{ - off_t small_poi_stack[POI_STACK_PREALLOC]; - off_t *poi_stack = small_poi_stack; - int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC; - - while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) { - off_t base_offset; - unsigned long size; - /* Push the object we're going to leave behind */ - if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) { - poi_stack_alloc = alloc_nr(poi_stack_nr); - ALLOC_ARRAY(poi_stack, poi_stack_alloc); - memcpy(poi_stack, small_poi_stack, sizeof(off_t)*poi_stack_nr); - } else { - ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc); - } - poi_stack[poi_stack_nr++] = obj_offset; - /* If parsing the base offset fails, just unwind */ - base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset); - if (!base_offset) - goto unwind; - curpos = obj_offset = base_offset; - type = unpack_object_header(p, w_curs, &curpos, &size); - if (type <= OBJ_NONE) { - /* If getting the base itself fails, we first - * retry the base, otherwise unwind */ - type = retry_bad_packed_offset(p, base_offset); - if (type > OBJ_NONE) - goto out; - goto unwind; - } - } - - switch (type) { - case OBJ_BAD: - case OBJ_COMMIT: - case OBJ_TREE: - case OBJ_BLOB: - case OBJ_TAG: - break; - default: - error("unknown object type %i at offset %"PRIuMAX" in %s", - type, (uintmax_t)obj_offset, p->pack_name); - type = OBJ_BAD; - } - -out: - if (poi_stack != small_poi_stack) - free(poi_stack); - return type; - -unwind: - while (poi_stack_nr) { - obj_offset = poi_stack[--poi_stack_nr]; - type = retry_bad_packed_offset(p, obj_offset); - if (type > OBJ_NONE) - goto out; - } - type = OBJ_BAD; - goto out; -} - -static struct hashmap delta_base_cache; -static size_t delta_base_cached; - -static LIST_HEAD(delta_base_cache_lru); - -struct delta_base_cache_key { - struct packed_git *p; - off_t base_offset; -}; - -struct delta_base_cache_entry { - struct hashmap hash; - struct delta_base_cache_key key; - struct list_head lru; - void *data; - unsigned long size; - enum object_type type; -}; - -static unsigned int pack_entry_hash(struct packed_git *p, off_t base_offset) -{ - unsigned int hash; - - hash = (unsigned int)(intptr_t)p + (unsigned int)base_offset; - hash += (hash >> 8) + (hash >> 16); - return hash; -} - -static struct delta_base_cache_entry * -get_delta_base_cache_entry(struct packed_git *p, off_t base_offset) -{ - struct hashmap_entry entry; - struct delta_base_cache_key key; - - if (!delta_base_cache.cmpfn) - return NULL; - - hashmap_entry_init(&entry, pack_entry_hash(p, base_offset)); - key.p = p; - key.base_offset = base_offset; - return hashmap_get(&delta_base_cache, &entry, &key); -} - -static int delta_base_cache_key_eq(const struct delta_base_cache_key *a, - const struct delta_base_cache_key *b) -{ - return a->p == b->p && a->base_offset == b->base_offset; -} - -static int delta_base_cache_hash_cmp(const void *unused_cmp_data, - const void *va, const void *vb, - const void *vkey) -{ - const struct delta_base_cache_entry *a = va, *b = vb; - const struct delta_base_cache_key *key = vkey; - if (key) - return !delta_base_cache_key_eq(&a->key, key); - else - return !delta_base_cache_key_eq(&a->key, &b->key); -} - -static int in_delta_base_cache(struct packed_git *p, off_t base_offset) -{ - return !!get_delta_base_cache_entry(p, base_offset); -} - -/* - * Remove the entry from the cache, but do _not_ free the associated - * entry data. The caller takes ownership of the "data" buffer, and - * should copy out any fields it wants before detaching. - */ -static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent) -{ - hashmap_remove(&delta_base_cache, ent, &ent->key); - list_del(&ent->lru); - delta_base_cached -= ent->size; - free(ent); -} - -static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset, - unsigned long *base_size, enum object_type *type) -{ - struct delta_base_cache_entry *ent; - - ent = get_delta_base_cache_entry(p, base_offset); - if (!ent) - return unpack_entry(p, base_offset, type, base_size); - - if (type) - *type = ent->type; - if (base_size) - *base_size = ent->size; - return xmemdupz(ent->data, ent->size); -} - -static inline void release_delta_base_cache(struct delta_base_cache_entry *ent) -{ - free(ent->data); - detach_delta_base_cache_entry(ent); -} - -void clear_delta_base_cache(void) -{ - struct list_head *lru, *tmp; - list_for_each_safe(lru, tmp, &delta_base_cache_lru) { - struct delta_base_cache_entry *entry = - list_entry(lru, struct delta_base_cache_entry, lru); - release_delta_base_cache(entry); - } -} - -static void add_delta_base_cache(struct packed_git *p, off_t base_offset, - void *base, unsigned long base_size, enum object_type type) -{ - struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent)); - struct list_head *lru, *tmp; - - delta_base_cached += base_size; - - list_for_each_safe(lru, tmp, &delta_base_cache_lru) { - struct delta_base_cache_entry *f = - list_entry(lru, struct delta_base_cache_entry, lru); - if (delta_base_cached <= delta_base_cache_limit) - break; - release_delta_base_cache(f); - } - - ent->key.p = p; - ent->key.base_offset = base_offset; - ent->type = type; - ent->data = base; - ent->size = base_size; - list_add_tail(&ent->lru, &delta_base_cache_lru); - - if (!delta_base_cache.cmpfn) - hashmap_init(&delta_base_cache, delta_base_cache_hash_cmp, NULL, 0); - hashmap_entry_init(ent, pack_entry_hash(p, base_offset)); - hashmap_add(&delta_base_cache, ent); -} - -int packed_object_info(struct packed_git *p, off_t obj_offset, - struct object_info *oi) -{ - struct pack_window *w_curs = NULL; - unsigned long size; - off_t curpos = obj_offset; - enum object_type type; - - /* - * We always get the representation type, but only convert it to - * a "real" type later if the caller is interested. - */ - if (oi->contentp) { - *oi->contentp = cache_or_unpack_entry(p, obj_offset, oi->sizep, - &type); - if (!*oi->contentp) - type = OBJ_BAD; - } else { - type = unpack_object_header(p, &w_curs, &curpos, &size); - } - - if (!oi->contentp && oi->sizep) { - if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) { - off_t tmp_pos = curpos; - off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos, - type, obj_offset); - if (!base_offset) { - type = OBJ_BAD; - goto out; - } - *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos); - if (*oi->sizep == 0) { - type = OBJ_BAD; - goto out; - } - } else { - *oi->sizep = size; - } - } - - if (oi->disk_sizep) { - struct revindex_entry *revidx = find_pack_revindex(p, obj_offset); - *oi->disk_sizep = revidx[1].offset - obj_offset; - } - - if (oi->typep || oi->typename) { - enum object_type ptot; - ptot = packed_to_object_type(p, obj_offset, type, &w_curs, - curpos); - if (oi->typep) - *oi->typep = ptot; - if (oi->typename) { - const char *tn = typename(ptot); - if (tn) - strbuf_addstr(oi->typename, tn); - } - if (ptot < 0) { - type = OBJ_BAD; - goto out; - } - } - - if (oi->delta_base_sha1) { - if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) { - const unsigned char *base; - - base = get_delta_base_sha1(p, &w_curs, curpos, - type, obj_offset); - if (!base) { - type = OBJ_BAD; - goto out; - } - - hashcpy(oi->delta_base_sha1, base); - } else - hashclr(oi->delta_base_sha1); - } - - oi->whence = in_delta_base_cache(p, obj_offset) ? OI_DBCACHED : - OI_PACKED; - -out: - unuse_pack(&w_curs); - return type; -} - -static void *unpack_compressed_entry(struct packed_git *p, - struct pack_window **w_curs, - off_t curpos, - unsigned long size) -{ - int st; - git_zstream stream; - unsigned char *buffer, *in; - - buffer = xmallocz_gently(size); - if (!buffer) - return NULL; - memset(&stream, 0, sizeof(stream)); - stream.next_out = buffer; - stream.avail_out = size + 1; - - git_inflate_init(&stream); - do { - in = use_pack(p, w_curs, curpos, &stream.avail_in); - stream.next_in = in; - st = git_inflate(&stream, Z_FINISH); - if (!stream.avail_out) - break; /* the payload is larger than it should be */ - curpos += stream.next_in - in; - } while (st == Z_OK || st == Z_BUF_ERROR); - git_inflate_end(&stream); - if ((st != Z_STREAM_END) || stream.total_out != size) { - free(buffer); - return NULL; - } - - return buffer; -} - -static void *read_object(const unsigned char *sha1, enum object_type *type, - unsigned long *size); - -static void write_pack_access_log(struct packed_git *p, off_t obj_offset) -{ - static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS); - trace_printf_key(&pack_access, "%s %"PRIuMAX"\n", - p->pack_name, (uintmax_t)obj_offset); -} - -int do_check_packed_object_crc; - -#define UNPACK_ENTRY_STACK_PREALLOC 64 -struct unpack_entry_stack_ent { - off_t obj_offset; - off_t curpos; - unsigned long size; -}; - -void *unpack_entry(struct packed_git *p, off_t obj_offset, - enum object_type *final_type, unsigned long *final_size) -{ - struct pack_window *w_curs = NULL; - off_t curpos = obj_offset; - void *data = NULL; - unsigned long size; - enum object_type type; - struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC]; - struct unpack_entry_stack_ent *delta_stack = small_delta_stack; - int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC; - int base_from_cache = 0; - - write_pack_access_log(p, obj_offset); - - /* PHASE 1: drill down to the innermost base object */ - for (;;) { - off_t base_offset; - int i; - struct delta_base_cache_entry *ent; - - ent = get_delta_base_cache_entry(p, curpos); - if (ent) { - type = ent->type; - data = ent->data; - size = ent->size; - detach_delta_base_cache_entry(ent); - base_from_cache = 1; - break; - } - - if (do_check_packed_object_crc && p->index_version > 1) { - struct revindex_entry *revidx = find_pack_revindex(p, obj_offset); - off_t len = revidx[1].offset - obj_offset; - if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) { - const unsigned char *sha1 = - nth_packed_object_sha1(p, revidx->nr); - error("bad packed object CRC for %s", - sha1_to_hex(sha1)); - mark_bad_packed_object(p, sha1); - data = NULL; - goto out; - } - } - - type = unpack_object_header(p, &w_curs, &curpos, &size); - if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA) - break; - - base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset); - if (!base_offset) { - error("failed to validate delta base reference " - "at offset %"PRIuMAX" from %s", - (uintmax_t)curpos, p->pack_name); - /* bail to phase 2, in hopes of recovery */ - data = NULL; - break; - } - - /* push object, proceed to base */ - if (delta_stack_nr >= delta_stack_alloc - && delta_stack == small_delta_stack) { - delta_stack_alloc = alloc_nr(delta_stack_nr); - ALLOC_ARRAY(delta_stack, delta_stack_alloc); - memcpy(delta_stack, small_delta_stack, - sizeof(*delta_stack)*delta_stack_nr); - } else { - ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc); - } - i = delta_stack_nr++; - delta_stack[i].obj_offset = obj_offset; - delta_stack[i].curpos = curpos; - delta_stack[i].size = size; - - curpos = obj_offset = base_offset; - } - - /* PHASE 2: handle the base */ - switch (type) { - case OBJ_OFS_DELTA: - case OBJ_REF_DELTA: - if (data) - die("BUG: unpack_entry: left loop at a valid delta"); - break; - case OBJ_COMMIT: - case OBJ_TREE: - case OBJ_BLOB: - case OBJ_TAG: - if (!base_from_cache) - data = unpack_compressed_entry(p, &w_curs, curpos, size); - break; - default: - data = NULL; - error("unknown object type %i at offset %"PRIuMAX" in %s", - type, (uintmax_t)obj_offset, p->pack_name); - } - - /* PHASE 3: apply deltas in order */ - - /* invariants: - * 'data' holds the base data, or NULL if there was corruption - */ - while (delta_stack_nr) { - void *delta_data; - void *base = data; - void *external_base = NULL; - unsigned long delta_size, base_size = size; - int i; - - data = NULL; - - if (base) - add_delta_base_cache(p, obj_offset, base, base_size, type); - - if (!base) { - /* - * We're probably in deep shit, but let's try to fetch - * the required base anyway from another pack or loose. - * This is costly but should happen only in the presence - * of a corrupted pack, and is better than failing outright. - */ - struct revindex_entry *revidx; - const unsigned char *base_sha1; - revidx = find_pack_revindex(p, obj_offset); - if (revidx) { - base_sha1 = nth_packed_object_sha1(p, revidx->nr); - error("failed to read delta base object %s" - " at offset %"PRIuMAX" from %s", - sha1_to_hex(base_sha1), (uintmax_t)obj_offset, - p->pack_name); - mark_bad_packed_object(p, base_sha1); - base = read_object(base_sha1, &type, &base_size); - external_base = base; - } - } - - i = --delta_stack_nr; - obj_offset = delta_stack[i].obj_offset; - curpos = delta_stack[i].curpos; - delta_size = delta_stack[i].size; - - if (!base) - continue; - - delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size); - - if (!delta_data) { - error("failed to unpack compressed delta " - "at offset %"PRIuMAX" from %s", - (uintmax_t)curpos, p->pack_name); - data = NULL; - free(external_base); - continue; - } - - data = patch_delta(base, base_size, - delta_data, delta_size, - &size); - - /* - * We could not apply the delta; warn the user, but keep going. - * Our failure will be noticed either in the next iteration of - * the loop, or if this is the final delta, in the caller when - * we return NULL. Those code paths will take care of making - * a more explicit warning and retrying with another copy of - * the object. - */ - if (!data) - error("failed to apply delta"); - - free(delta_data); - free(external_base); - } - - if (final_type) - *final_type = type; - if (final_size) - *final_size = size; - -out: - unuse_pack(&w_curs); - - if (delta_stack != small_delta_stack) - free(delta_stack); - - return data; -} - const unsigned char *nth_packed_object_sha1(struct packed_git *p, uint32_t n) { @@ -2082,6 +1433,20 @@ int sha1_object_info(const unsigned char *sha1, unsigned long *sizep) return type; } +static void *read_object(const unsigned char *sha1, enum object_type *type, + unsigned long *size) +{ + struct object_info oi = OBJECT_INFO_INIT; + void *content; + oi.typep = type; + oi.sizep = size; + oi.contentp = &content; + + if (sha1_object_info_extended(sha1, &oi, 0) < 0) + return NULL; + return content; +} + int pretend_sha1_file(void *buf, unsigned long len, enum object_type type, unsigned char *sha1) { @@ -2100,20 +1465,6 @@ int pretend_sha1_file(void *buf, unsigned long len, enum object_type type, return 0; } -static void *read_object(const unsigned char *sha1, enum object_type *type, - unsigned long *size) -{ - struct object_info oi = OBJECT_INFO_INIT; - void *content; - oi.typep = type; - oi.sizep = size; - oi.contentp = &content; - - if (sha1_object_info_extended(sha1, &oi, 0) < 0) - return NULL; - return content; -} - /* * This function dies on corrupt objects; the callers who want to * deal with them should arrange to call read_object() and give error
-- 2.14.1.480.gb18f417b89-goog