/* * GIT - The information manager from hell * * Copyright (C) Linus Torvalds, 2005 * * This handles basic git sha1 object files - packing, unpacking, * creation etc. */ #include "cache.h" #include "delta.h" #include "pack.h" #include "blob.h" #include "commit.h" #include "run-command.h" #include "tag.h" #include "tree.h" #include "tree-walk.h" #include "refs.h" #include "pack-revindex.h" #include "sha1-lookup.h" #ifndef O_NOATIME #if defined(__linux__) && (defined(__i386__) || defined(__PPC__)) #define O_NOATIME 01000000 #else #define O_NOATIME 0 #endif #endif #define SZ_FMT PRIuMAX static inline uintmax_t sz_fmt(size_t s) { return s; } const unsigned char null_sha1[20]; /* * This is meant to hold a *small* number of objects that you would * want read_sha1_file() to be able to return, but yet you do not want * to write them into the object store (e.g. a browse-only * application). */ static struct cached_object { unsigned char sha1[20]; enum object_type type; void *buf; unsigned long size; } *cached_objects; static int cached_object_nr, cached_object_alloc; static struct cached_object empty_tree = { EMPTY_TREE_SHA1_BIN_LITERAL, OBJ_TREE, "", 0 }; static struct cached_object *find_cached_object(const unsigned char *sha1) { int i; struct cached_object *co = cached_objects; for (i = 0; i < cached_object_nr; i++, co++) { if (!hashcmp(co->sha1, sha1)) return co; } if (!hashcmp(sha1, empty_tree.sha1)) return &empty_tree; return NULL; } int mkdir_in_gitdir(const char *path) { if (mkdir(path, 0777)) { int saved_errno = errno; struct stat st; struct strbuf sb = STRBUF_INIT; if (errno != EEXIST) return -1; /* * Are we looking at a path in a symlinked worktree * whose original repository does not yet have it? * e.g. .git/rr-cache pointing at its original * repository in which the user hasn't performed any * conflict resolution yet? */ if (lstat(path, &st) || !S_ISLNK(st.st_mode) || strbuf_readlink(&sb, path, st.st_size) || !is_absolute_path(sb.buf) || mkdir(sb.buf, 0777)) { strbuf_release(&sb); errno = saved_errno; return -1; } strbuf_release(&sb); } return adjust_shared_perm(path); } int safe_create_leading_directories(char *path) { char *pos = path + offset_1st_component(path); struct stat st; while (pos) { pos = strchr(pos, '/'); if (!pos) break; while (*++pos == '/') ; if (!*pos) break; *--pos = '\0'; if (!stat(path, &st)) { /* path exists */ if (!S_ISDIR(st.st_mode)) { *pos = '/'; return -3; } } else if (mkdir(path, 0777)) { *pos = '/'; return -1; } else if (adjust_shared_perm(path)) { *pos = '/'; return -2; } *pos++ = '/'; } return 0; } int safe_create_leading_directories_const(const char *path) { /* path points to cache entries, so xstrdup before messing with it */ char *buf = xstrdup(path); int result = safe_create_leading_directories(buf); free(buf); return result; } static void fill_sha1_path(char *pathbuf, const unsigned char *sha1) { int i; for (i = 0; i < 20; i++) { static char hex[] = "0123456789abcdef"; unsigned int val = sha1[i]; char *pos = pathbuf + i*2 + (i > 0); *pos++ = hex[val >> 4]; *pos = hex[val & 0xf]; } } /* * NOTE! This returns a statically allocated buffer, so you have to be * careful about using it. Do an "xstrdup()" if you need to save the * filename. * * Also note that this returns the location for creating. Reading * SHA1 file can happen from any alternate directory listed in the * DB_ENVIRONMENT environment variable if it is not found in * the primary object database. */ char *sha1_file_name(const unsigned char *sha1) { static char buf[PATH_MAX]; const char *objdir; int len; objdir = get_object_directory(); len = strlen(objdir); /* '/' + sha1(2) + '/' + sha1(38) + '\0' */ if (len + 43 > PATH_MAX) die("insanely long object directory %s", objdir); memcpy(buf, objdir, len); buf[len] = '/'; buf[len+3] = '/'; buf[len+42] = '\0'; fill_sha1_path(buf + len + 1, sha1); return buf; } static char *sha1_get_pack_name(const unsigned char *sha1, char **name, char **base, const char *which) { static const char hex[] = "0123456789abcdef"; char *buf; int i; if (!*base) { const char *sha1_file_directory = get_object_directory(); int len = strlen(sha1_file_directory); *base = xmalloc(len + 60); sprintf(*base, "%s/pack/pack-1234567890123456789012345678901234567890.%s", sha1_file_directory, which); *name = *base + len + 11; } buf = *name; for (i = 0; i < 20; i++) { unsigned int val = *sha1++; *buf++ = hex[val >> 4]; *buf++ = hex[val & 0xf]; } return *base; } char *sha1_pack_name(const unsigned char *sha1) { static char *name, *base; return sha1_get_pack_name(sha1, &name, &base, "pack"); } char *sha1_pack_index_name(const unsigned char *sha1) { static char *name, *base; return sha1_get_pack_name(sha1, &name, &base, "idx"); } struct alternate_object_database *alt_odb_list; static struct alternate_object_database **alt_odb_tail; static void read_info_alternates(const char * alternates, int depth); static int git_open_noatime(const char *name); /* * Prepare alternate object database registry. * * The variable alt_odb_list points at the list of struct * alternate_object_database. The elements on this list come from * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates, * whose contents is similar to that environment variable but can be * LF separated. Its base points at a statically allocated buffer that * contains "/the/directory/corresponding/to/.git/objects/...", while * its name points just after the slash at the end of ".git/objects/" * in the example above, and has enough space to hold 40-byte hex * SHA1, an extra slash for the first level indirection, and the * terminating NUL. */ static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth) { const char *objdir = get_object_directory(); struct alternate_object_database *ent; struct alternate_object_database *alt; /* 43 = 40-byte + 2 '/' + terminating NUL */ int pfxlen = len; int entlen = pfxlen + 43; int base_len = -1; if (!is_absolute_path(entry) && relative_base) { /* Relative alt-odb */ if (base_len < 0) base_len = strlen(relative_base) + 1; entlen += base_len; pfxlen += base_len; } ent = xmalloc(sizeof(*ent) + entlen); if (!is_absolute_path(entry) && relative_base) { memcpy(ent->base, relative_base, base_len - 1); ent->base[base_len - 1] = '/'; memcpy(ent->base + base_len, entry, len); } else memcpy(ent->base, entry, pfxlen); ent->name = ent->base + pfxlen + 1; ent->base[pfxlen + 3] = '/'; ent->base[pfxlen] = ent->base[entlen-1] = 0; /* Detect cases where alternate disappeared */ if (!is_directory(ent->base)) { error("object directory %s does not exist; " "check .git/objects/info/alternates.", ent->base); free(ent); return -1; } /* Prevent the common mistake of listing the same * thing twice, or object directory itself. */ for (alt = alt_odb_list; alt; alt = alt->next) { if (!memcmp(ent->base, alt->base, pfxlen)) { free(ent); return -1; } } if (!memcmp(ent->base, objdir, pfxlen)) { free(ent); return -1; } /* add the alternate entry */ *alt_odb_tail = ent; alt_odb_tail = &(ent->next); ent->next = NULL; /* recursively add alternates */ read_info_alternates(ent->base, depth + 1); ent->base[pfxlen] = '/'; return 0; } static void link_alt_odb_entries(const char *alt, const char *ep, int sep, const char *relative_base, int depth) { const char *cp, *last; if (depth > 5) { error("%s: ignoring alternate object stores, nesting too deep.", relative_base); return; } last = alt; while (last < ep) { cp = last; if (cp < ep && *cp == '#') { while (cp < ep && *cp != sep) cp++; last = cp + 1; continue; } while (cp < ep && *cp != sep) cp++; if (last != cp) { if (!is_absolute_path(last) && depth) { error("%s: ignoring relative alternate object store %s", relative_base, last); } else { link_alt_odb_entry(last, cp - last, relative_base, depth); } } while (cp < ep && *cp == sep) cp++; last = cp; } } static void read_info_alternates(const char * relative_base, int depth) { char *map; size_t mapsz; struct stat st; const char alt_file_name[] = "info/alternates"; /* Given that relative_base is no longer than PATH_MAX, ensure that "path" has enough space to append "/", the file name, "info/alternates", and a trailing NUL. */ char path[PATH_MAX + 1 + sizeof alt_file_name]; int fd; sprintf(path, "%s/%s", relative_base, alt_file_name); fd = git_open_noatime(path); if (fd < 0) return; if (fstat(fd, &st) || (st.st_size == 0)) { close(fd); return; } mapsz = xsize_t(st.st_size); map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0); close(fd); link_alt_odb_entries(map, map + mapsz, '\n', relative_base, depth); munmap(map, mapsz); } void add_to_alternates_file(const char *reference) { struct lock_file *lock = xcalloc(1, sizeof(struct lock_file)); int fd = hold_lock_file_for_append(lock, git_path("objects/info/alternates"), LOCK_DIE_ON_ERROR); char *alt = mkpath("%s/objects\n", reference); write_or_die(fd, alt, strlen(alt)); if (commit_lock_file(lock)) die("could not close alternates file"); if (alt_odb_tail) link_alt_odb_entries(alt, alt + strlen(alt), '\n', NULL, 0); } void foreach_alt_odb(alt_odb_fn fn, void *cb) { struct alternate_object_database *ent; prepare_alt_odb(); for (ent = alt_odb_list; ent; ent = ent->next) if (fn(ent, cb)) return; } void prepare_alt_odb(void) { const char *alt; if (alt_odb_tail) return; alt = getenv(ALTERNATE_DB_ENVIRONMENT); if (!alt) alt = ""; alt_odb_tail = &alt_odb_list; link_alt_odb_entries(alt, alt + strlen(alt), PATH_SEP, NULL, 0); read_info_alternates(get_object_directory(), 0); } static int has_loose_object_local(const unsigned char *sha1) { char *name = sha1_file_name(sha1); return !access(name, F_OK); } int has_loose_object_nonlocal(const unsigned char *sha1) { struct alternate_object_database *alt; prepare_alt_odb(); for (alt = alt_odb_list; alt; alt = alt->next) { fill_sha1_path(alt->name, sha1); if (!access(alt->base, F_OK)) return 1; } return 0; } static int has_loose_object(const unsigned char *sha1) { return has_loose_object_local(sha1) || has_loose_object_nonlocal(sha1); } static unsigned int pack_used_ctr; static unsigned int pack_mmap_calls; static unsigned int peak_pack_open_windows; static unsigned int pack_open_windows; static unsigned int pack_open_fds; static unsigned int pack_max_fds; static size_t peak_pack_mapped; static size_t pack_mapped; struct packed_git *packed_git; void pack_report(void) { fprintf(stderr, "pack_report: getpagesize() = %10" SZ_FMT "\n" "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n" "pack_report: core.packedGitLimit = %10" SZ_FMT "\n", sz_fmt(getpagesize()), sz_fmt(packed_git_window_size), sz_fmt(packed_git_limit)); fprintf(stderr, "pack_report: pack_used_ctr = %10u\n" "pack_report: pack_mmap_calls = %10u\n" "pack_report: pack_open_windows = %10u / %10u\n" "pack_report: pack_mapped = " "%10" SZ_FMT " / %10" SZ_FMT "\n", pack_used_ctr, pack_mmap_calls, pack_open_windows, peak_pack_open_windows, sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped)); } static int check_packed_git_idx(const char *path, struct packed_git *p) { void *idx_map; struct pack_idx_header *hdr; size_t idx_size; uint32_t version, nr, i, *index; int fd = git_open_noatime(path); struct stat st; if (fd < 0) return -1; if (fstat(fd, &st)) { close(fd); return -1; } idx_size = xsize_t(st.st_size); if (idx_size < 4 * 256 + 20 + 20) { close(fd); return error("index file %s is too small", path); } idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0); close(fd); hdr = idx_map; if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) { version = ntohl(hdr->idx_version); if (version < 2 || version > 2) { munmap(idx_map, idx_size); return error("index file %s is version %"PRIu32 " and is not supported by this binary" " (try upgrading GIT to a newer version)", path, version); } } else version = 1; nr = 0; index = idx_map; if (version > 1) index += 2; /* skip index header */ for (i = 0; i < 256; i++) { uint32_t n = ntohl(index[i]); if (n < nr) { munmap(idx_map, idx_size); return error("non-monotonic index %s", path); } nr = n; } if (version == 1) { /* * Total size: * - 256 index entries 4 bytes each * - 24-byte entries * nr (20-byte sha1 + 4-byte offset) * - 20-byte SHA1 of the packfile * - 20-byte SHA1 file checksum */ if (idx_size != 4*256 + nr * 24 + 20 + 20) { munmap(idx_map, idx_size); return error("wrong index v1 file size in %s", path); } } else if (version == 2) { /* * Minimum size: * - 8 bytes of header * - 256 index entries 4 bytes each * - 20-byte sha1 entry * nr * - 4-byte crc entry * nr * - 4-byte offset entry * nr * - 20-byte SHA1 of the packfile * - 20-byte SHA1 file checksum * And after the 4-byte offset table might be a * variable sized table containing 8-byte entries * for offsets larger than 2^31. */ unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20; unsigned long max_size = min_size; if (nr) max_size += (nr - 1)*8; if (idx_size < min_size || idx_size > max_size) { munmap(idx_map, idx_size); return error("wrong index v2 file size in %s", path); } if (idx_size != min_size && /* * make sure we can deal with large pack offsets. * 31-bit signed offset won't be enough, neither * 32-bit unsigned one will be. */ (sizeof(off_t) <= 4)) { munmap(idx_map, idx_size); return error("pack too large for current definition of off_t in %s", path); } } p->index_version = version; p->index_data = idx_map; p->index_size = idx_size; p->num_objects = nr; return 0; } int open_pack_index(struct packed_git *p) { char *idx_name; int ret; if (p->index_data) return 0; idx_name = xstrdup(p->pack_name); strcpy(idx_name + strlen(idx_name) - strlen(".pack"), ".idx"); ret = check_packed_git_idx(idx_name, p); free(idx_name); return ret; } static void scan_windows(struct packed_git *p, struct packed_git **lru_p, struct pack_window **lru_w, struct pack_window **lru_l) { struct pack_window *w, *w_l; for (w_l = NULL, w = p->windows; w; w = w->next) { if (!w->inuse_cnt) { if (!*lru_w || w->last_used < (*lru_w)->last_used) { *lru_p = p; *lru_w = w; *lru_l = w_l; } } w_l = w; } } static int unuse_one_window(struct packed_git *current, int keep_fd) { struct packed_git *p, *lru_p = NULL; struct pack_window *lru_w = NULL, *lru_l = NULL; if (current) scan_windows(current, &lru_p, &lru_w, &lru_l); for (p = packed_git; p; p = p->next) scan_windows(p, &lru_p, &lru_w, &lru_l); if (lru_p) { munmap(lru_w->base, lru_w->len); pack_mapped -= lru_w->len; if (lru_l) lru_l->next = lru_w->next; else { lru_p->windows = lru_w->next; if (!lru_p->windows && lru_p->pack_fd != -1 && lru_p->pack_fd != keep_fd) { close(lru_p->pack_fd); pack_open_fds--; lru_p->pack_fd = -1; } } free(lru_w); pack_open_windows--; return 1; } return 0; } void release_pack_memory(size_t need, int fd) { size_t cur = pack_mapped; while (need >= (cur - pack_mapped) && unuse_one_window(NULL, fd)) ; /* nothing */ } void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset) { void *ret = mmap(start, length, prot, flags, fd, offset); if (ret == MAP_FAILED) { if (!length) return NULL; release_pack_memory(length, fd); ret = mmap(start, length, prot, flags, fd, offset); if (ret == MAP_FAILED) die_errno("Out of memory? mmap failed"); } return ret; } void close_pack_windows(struct packed_git *p) { while (p->windows) { struct pack_window *w = p->windows; if (w->inuse_cnt) die("pack '%s' still has open windows to it", p->pack_name); munmap(w->base, w->len); pack_mapped -= w->len; pack_open_windows--; p->windows = w->next; free(w); } } void unuse_pack(struct pack_window **w_cursor) { struct pack_window *w = *w_cursor; if (w) { w->inuse_cnt--; *w_cursor = NULL; } } void close_pack_index(struct packed_git *p) { if (p->index_data) { munmap((void *)p->index_data, p->index_size); p->index_data = NULL; } } /* * This is used by git-repack in case a newly created pack happens to * contain the same set of objects as an existing one. In that case * the resulting file might be different even if its name would be the * same. It is best to close any reference to the old pack before it is * replaced on disk. Of course no index pointers nor windows for given pack * must subsist at this point. If ever objects from this pack are requested * again, the new version of the pack will be reinitialized through * reprepare_packed_git(). */ void free_pack_by_name(const char *pack_name) { struct packed_git *p, **pp = &packed_git; while (*pp) { p = *pp; if (strcmp(pack_name, p->pack_name) == 0) { clear_delta_base_cache(); close_pack_windows(p); if (p->pack_fd != -1) { close(p->pack_fd); pack_open_fds--; } close_pack_index(p); free(p->bad_object_sha1); *pp = p->next; free(p); return; } pp = &p->next; } } /* * Do not call this directly as this leaks p->pack_fd on error return; * call open_packed_git() instead. */ static int open_packed_git_1(struct packed_git *p) { struct stat st; struct pack_header hdr; unsigned char sha1[20]; unsigned char *idx_sha1; long fd_flag; if (!p->index_data && open_pack_index(p)) return error("packfile %s index unavailable", p->pack_name); if (!pack_max_fds) { struct rlimit lim; unsigned int max_fds; if (getrlimit(RLIMIT_NOFILE, &lim)) die_errno("cannot get RLIMIT_NOFILE"); max_fds = lim.rlim_cur; /* Save 3 for stdin/stdout/stderr, 22 for work */ if (25 < max_fds) pack_max_fds = max_fds - 25; else pack_max_fds = 1; } while (pack_max_fds <= pack_open_fds && unuse_one_window(NULL, -1)) ; /* nothing */ p->pack_fd = git_open_noatime(p->pack_name); if (p->pack_fd < 0 || fstat(p->pack_fd, &st)) return -1; pack_open_fds++; /* If we created the struct before we had the pack we lack size. */ if (!p->pack_size) { if (!S_ISREG(st.st_mode)) return error("packfile %s not a regular file", p->pack_name); p->pack_size = st.st_size; } else if (p->pack_size != st.st_size) return error("packfile %s size changed", p->pack_name); /* We leave these file descriptors open with sliding mmap; * there is no point keeping them open across exec(), though. */ fd_flag = fcntl(p->pack_fd, F_GETFD, 0); if (fd_flag < 0) return error("cannot determine file descriptor flags"); fd_flag |= FD_CLOEXEC; if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1) return error("cannot set FD_CLOEXEC"); /* Verify we recognize this pack file format. */ if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr)) return error("file %s is far too short to be a packfile", p->pack_name); if (hdr.hdr_signature != htonl(PACK_SIGNATURE)) return error("file %s is not a GIT packfile", p->pack_name); if (!pack_version_ok(hdr.hdr_version)) return error("packfile %s is version %"PRIu32" and not" " supported (try upgrading GIT to a newer version)", p->pack_name, ntohl(hdr.hdr_version)); /* Verify the pack matches its index. */ if (p->num_objects != ntohl(hdr.hdr_entries)) return error("packfile %s claims to have %"PRIu32" objects" " while index indicates %"PRIu32" objects", p->pack_name, ntohl(hdr.hdr_entries), p->num_objects); if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1) 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_data) + p->index_size - 40; if (hashcmp(sha1, idx_sha1)) return error("packfile %s does not match index", p->pack_name); return 0; } static int open_packed_git(struct packed_git *p) { if (!open_packed_git_1(p)) return 0; if (p->pack_fd != -1) { close(p->pack_fd); pack_open_fds--; p->pack_fd = -1; } return -1; } static int in_window(struct pack_window *win, off_t offset) { /* We must promise at least 20 bytes (one hash) after the * offset is available from this window, otherwise the offset * is not actually in this window and a different window (which * has that one hash excess) must be used. This is to support * the object header and delta base parsing routines below. */ off_t win_off = win->offset; return win_off <= offset && (offset + 20) <= (win_off + win->len); } unsigned char *use_pack(struct packed_git *p, struct pack_window **w_cursor, off_t offset, unsigned int *left) { struct pack_window *win = *w_cursor; /* Since packfiles end in a hash of their content and it's * pointless to ask for an offset into the middle of that * hash, and the in_window function above wouldn't match * don't allow an offset too close to the end of the file. */ if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p)) die("packfile %s cannot be accessed", p->pack_name); if (offset > (p->pack_size - 20)) die("offset beyond end of packfile (truncated pack?)"); if (!win || !in_window(win, offset)) { if (win) win->inuse_cnt--; for (win = p->windows; win; win = win->next) { if (in_window(win, offset)) break; } if (!win) { size_t window_align = packed_git_window_size / 2; off_t len; if (p->pack_fd == -1 && open_packed_git(p)) die("packfile %s cannot be accessed", p->pack_name); win = xcalloc(1, sizeof(*win)); win->offset = (offset / window_align) * window_align; len = p->pack_size - win->offset; if (len > packed_git_window_size) len = packed_git_window_size; win->len = (size_t)len; pack_mapped += win->len; while (packed_git_limit < pack_mapped && unuse_one_window(p, p->pack_fd)) ; /* nothing */ win->base = xmmap(NULL, win->len, PROT_READ, MAP_PRIVATE, p->pack_fd, win->offset); if (win->base == MAP_FAILED) die("packfile %s cannot be mapped: %s", p->pack_name, strerror(errno)); if (!win->offset && win->len == p->pack_size && !p->do_not_close) { close(p->pack_fd); pack_open_fds--; p->pack_fd = -1; } pack_mmap_calls++; pack_open_windows++; if (pack_mapped > peak_pack_mapped) peak_pack_mapped = pack_mapped; if (pack_open_windows > peak_pack_open_windows) peak_pack_open_windows = pack_open_windows; win->next = p->windows; p->windows = win; } } if (win != *w_cursor) { win->last_used = pack_used_ctr++; win->inuse_cnt++; *w_cursor = win; } offset -= win->offset; if (left) *left = win->len - xsize_t(offset); return win->base + offset; } static struct packed_git *alloc_packed_git(int extra) { struct packed_git *p = xmalloc(sizeof(*p) + extra); memset(p, 0, sizeof(*p)); p->pack_fd = -1; return p; } static void try_to_free_pack_memory(size_t size) { release_pack_memory(size, -1); } struct packed_git *add_packed_git(const char *path, int path_len, int local) { static int have_set_try_to_free_routine; struct stat st; struct packed_git *p = alloc_packed_git(path_len + 2); if (!have_set_try_to_free_routine) { have_set_try_to_free_routine = 1; set_try_to_free_routine(try_to_free_pack_memory); } /* * Make sure a corresponding .pack file exists and that * the index looks sane. */ path_len -= strlen(".idx"); if (path_len < 1) { free(p); return NULL; } memcpy(p->pack_name, path, path_len); strcpy(p->pack_name + path_len, ".keep"); if (!access(p->pack_name, F_OK)) p->pack_keep = 1; strcpy(p->pack_name + path_len, ".pack"); if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) { free(p); return NULL; } /* ok, it looks sane as far as we can check without * actually mapping the pack file. */ p->pack_size = st.st_size; p->pack_local = local; p->mtime = st.st_mtime; if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1)) hashclr(p->sha1); return p; } struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path) { const char *path = sha1_pack_name(sha1); struct packed_git *p = alloc_packed_git(strlen(path) + 1); strcpy(p->pack_name, path); hashcpy(p->sha1, sha1); if (check_packed_git_idx(idx_path, p)) { free(p); return NULL; } return p; } void install_packed_git(struct packed_git *pack) { if (pack->pack_fd != -1) pack_open_fds++; pack->next = packed_git; packed_git = pack; } static void prepare_packed_git_one(char *objdir, int local) { /* Ensure that this buffer is large enough so that we can append "/pack/" without clobbering the stack even if strlen(objdir) were PATH_MAX. */ char path[PATH_MAX + 1 + 4 + 1 + 1]; int len; DIR *dir; struct dirent *de; sprintf(path, "%s/pack", objdir); len = strlen(path); dir = opendir(path); if (!dir) { if (errno != ENOENT) error("unable to open object pack directory: %s: %s", path, strerror(errno)); return; } path[len++] = '/'; while ((de = readdir(dir)) != NULL) { int namelen = strlen(de->d_name); struct packed_git *p; if (!has_extension(de->d_name, ".idx")) continue; if (len + namelen + 1 > sizeof(path)) continue; /* Don't reopen a pack we already have. */ strcpy(path + len, de->d_name); for (p = packed_git; p; p = p->next) { if (!memcmp(path, p->pack_name, len + namelen - 4)) break; } if (p) continue; /* See if it really is a valid .idx file with corresponding * .pack file that we can map. */ p = add_packed_git(path, len + namelen, local); if (!p) continue; install_packed_git(p); } closedir(dir); } static int sort_pack(const void *a_, const void *b_) { struct packed_git *a = *((struct packed_git **)a_); struct packed_git *b = *((struct packed_git **)b_); int st; /* * Local packs tend to contain objects specific to our * variant of the project than remote ones. In addition, * remote ones could be on a network mounted filesystem. * Favor local ones for these reasons. */ st = a->pack_local - b->pack_local; if (st) return -st; /* * Younger packs tend to contain more recent objects, * and more recent objects tend to get accessed more * often. */ if (a->mtime < b->mtime) return 1; else if (a->mtime == b->mtime) return 0; return -1; } static void rearrange_packed_git(void) { struct packed_git **ary, *p; int i, n; for (n = 0, p = packed_git; p; p = p->next) n++; if (n < 2) return; /* prepare an array of packed_git for easier sorting */ ary = xcalloc(n, sizeof(struct packed_git *)); for (n = 0, p = packed_git; p; p = p->next) ary[n++] = p; qsort(ary, n, sizeof(struct packed_git *), sort_pack); /* link them back again */ for (i = 0; i < n - 1; i++) ary[i]->next = ary[i + 1]; ary[n - 1]->next = NULL; packed_git = ary[0]; free(ary); } static int prepare_packed_git_run_once = 0; void prepare_packed_git(void) { struct alternate_object_database *alt; if (prepare_packed_git_run_once) return; prepare_packed_git_one(get_object_directory(), 1); prepare_alt_odb(); for (alt = alt_odb_list; alt; alt = alt->next) { alt->name[-1] = 0; prepare_packed_git_one(alt->base, 0); alt->name[-1] = '/'; } rearrange_packed_git(); prepare_packed_git_run_once = 1; } void reprepare_packed_git(void) { discard_revindex(); prepare_packed_git_run_once = 0; prepare_packed_git(); } 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 + 20 * i)) return; p->bad_object_sha1 = xrealloc(p->bad_object_sha1, 20 * (p->num_bad_objects + 1)); hashcpy(p->bad_object_sha1 + 20 * 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; } int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type) { unsigned char real_sha1[20]; hash_sha1_file(map, size, type, real_sha1); return hashcmp(sha1, real_sha1) ? -1 : 0; } static int git_open_noatime(const char *name) { static int sha1_file_open_flag = O_NOATIME; for (;;) { int fd = open(name, O_RDONLY | sha1_file_open_flag); if (fd >= 0) return fd; /* Might the failure be due to O_NOATIME? */ if (errno != ENOENT && sha1_file_open_flag) { sha1_file_open_flag = 0; continue; } return -1; } } static int open_sha1_file(const unsigned char *sha1) { int fd; char *name = sha1_file_name(sha1); struct alternate_object_database *alt; fd = git_open_noatime(name); if (fd >= 0) return fd; prepare_alt_odb(); errno = ENOENT; for (alt = alt_odb_list; alt; alt = alt->next) { name = alt->name; fill_sha1_path(name, sha1); fd = git_open_noatime(alt->base); if (fd >= 0) return fd; } return -1; } void *map_sha1_file(const unsigned char *sha1, unsigned long *size) { void *map; int fd; fd = open_sha1_file(sha1); map = NULL; if (fd >= 0) { struct stat st; if (!fstat(fd, &st)) { *size = xsize_t(st.st_size); map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0); } close(fd); } return map; } /* * There used to be a second loose object header format which * was meant to mimic the in-pack format, allowing for direct * copy of the object data. This format turned up not to be * really worth it and we no longer write loose objects in that * format. */ static int experimental_loose_object(unsigned char *map) { unsigned int word; /* * Is it a zlib-compressed buffer? If so, the first byte * must be 0x78 (15-bit window size, deflated), and the * first 16-bit word is evenly divisible by 31. If so, * we are looking at the official format, not the experimental * one. */ word = (map[0] << 8) + map[1]; if (map[0] == 0x78 && !(word % 31)) return 0; else return 1; } unsigned long unpack_object_header_buffer(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep) { unsigned shift; unsigned long size, c; unsigned long used = 0; c = buf[used++]; *type = (c >> 4) & 7; size = c & 15; shift = 4; while (c & 0x80) { if (len <= used || bitsizeof(long) <= shift) { error("bad object header"); return 0; } c = buf[used++]; size += (c & 0x7f) << shift; shift += 7; } *sizep = size; return used; } int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz) { unsigned long size, used; static const char valid_loose_object_type[8] = { 0, /* OBJ_EXT */ 1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */ 0, /* "delta" and others are invalid in a loose object */ }; enum object_type type; /* Get the data stream */ memset(stream, 0, sizeof(*stream)); stream->next_in = map; stream->avail_in = mapsize; stream->next_out = buffer; stream->avail_out = bufsiz; if (experimental_loose_object(map)) { /* * The old experimental format we no longer produce; * we can still read it. */ used = unpack_object_header_buffer(map, mapsize, &type, &size); if (!used || !valid_loose_object_type[type]) return -1; map += used; mapsize -= used; /* Set up the stream for the rest.. */ stream->next_in = map; stream->avail_in = mapsize; git_inflate_init(stream); /* And generate the fake traditional header */ stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu", typename(type), size); return 0; } git_inflate_init(stream); return git_inflate(stream, 0); } static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size, const unsigned char *sha1) { int bytes = strlen(buffer) + 1; unsigned char *buf = xmallocz(size); unsigned long n; int status = Z_OK; n = stream->total_out - bytes; if (n > size) n = size; memcpy(buf, (char *) buffer + bytes, n); bytes = n; if (bytes <= size) { /* * The above condition must be (bytes <= size), not * (bytes < size). In other words, even though we * expect no more output and set avail_out to zero, * the input zlib stream may have bytes that express * "this concludes the stream", and we *do* want to * eat that input. * * Otherwise we would not be able to test that we * consumed all the input to reach the expected size; * we also want to check that zlib tells us that all * went well with status == Z_STREAM_END at the end. */ stream->next_out = buf + bytes; stream->avail_out = size - bytes; while (status == Z_OK) status = git_inflate(stream, Z_FINISH); } if (status == Z_STREAM_END && !stream->avail_in) { git_inflate_end(stream); return buf; } if (status < 0) error("corrupt loose object '%s'", sha1_to_hex(sha1)); else if (stream->avail_in) error("garbage at end of loose object '%s'", sha1_to_hex(sha1)); free(buf); return NULL; } /* * We used to just use "sscanf()", but that's actually way * too permissive for what we want to check. So do an anal * object header parse by hand. */ int parse_sha1_header(const char *hdr, unsigned long *sizep) { char type[10]; int i; unsigned long size; /* * The type can be at most ten bytes (including the * terminating '\0' that we add), and is followed by * a space. */ i = 0; for (;;) { char c = *hdr++; if (c == ' ') break; type[i++] = c; if (i >= sizeof(type)) return -1; } type[i] = 0; /* * The length must follow immediately, and be in canonical * decimal format (ie "010" is not valid). */ size = *hdr++ - '0'; if (size > 9) return -1; if (size) { for (;;) { unsigned long c = *hdr - '0'; if (c > 9) break; hdr++; size = size * 10 + c; } } *sizep = size; /* * The length must be followed by a zero byte */ return *hdr ? -1 : type_from_string(type); } static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1) { int ret; z_stream stream; char hdr[8192]; ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)); if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0) return NULL; return unpack_sha1_rest(&stream, hdr, *size, sha1); } unsigned long get_size_from_delta(struct packed_git *p, struct pack_window **w_curs, off_t curpos) { const unsigned char *data; unsigned char delta_head[20], *in; z_stream stream; int st; memset(&stream, 0, sizeof(stream)); stream.next_out = delta_head; stream.avail_out = sizeof(delta_head); 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); curpos += stream.next_in - in; } while ((st == Z_OK || st == Z_BUF_ERROR) && stream.total_out < sizeof(delta_head)); git_inflate_end(&stream); if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) { error("delta data unpack-initial failed"); return 0; } /* Examine the initial part of the delta to figure out * the result size. */ data = delta_head; /* ignore base size */ get_delta_hdr_size(&data, delta_head+sizeof(delta_head)); /* Read the result size */ return get_delta_hdr_size(&data, delta_head+sizeof(delta_head)); } 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; } /* forward declaration for a mutually recursive function */ static int packed_object_info(struct packed_git *p, off_t offset, unsigned long *sizep, int *rtype); static int packed_delta_info(struct packed_git *p, struct pack_window **w_curs, off_t curpos, enum object_type type, off_t obj_offset, unsigned long *sizep) { off_t base_offset; base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset); if (!base_offset) return OBJ_BAD; type = packed_object_info(p, base_offset, NULL, NULL); if (type <= OBJ_NONE) { struct revindex_entry *revidx; const unsigned char *base_sha1; revidx = find_pack_revindex(p, base_offset); if (!revidx) return OBJ_BAD; base_sha1 = nth_packed_object_sha1(p, revidx->nr); mark_bad_packed_object(p, base_sha1); type = sha1_object_info(base_sha1, NULL); if (type <= OBJ_NONE) return OBJ_BAD; } /* We choose to only get the type of the base object and * ignore potentially corrupt pack file that expects the delta * based on a base with a wrong size. This saves tons of * inflate() calls. */ if (sizep) { *sizep = get_size_from_delta(p, w_curs, curpos); if (*sizep == 0) type = OBJ_BAD; } return type; } int unpack_object_header(struct packed_git *p, struct pack_window **w_curs, off_t *curpos, unsigned long *sizep) { unsigned char *base; unsigned int left; unsigned long used; enum object_type type; /* use_pack() assures us we have [base, base + 20) available * as a range that we can look at. (Its actually the hash * size that is assured.) With our object header encoding * the maximum deflated object size is 2^137, which is just * insane, so we know won't exceed what we have been given. */ base = use_pack(p, w_curs, *curpos, &left); used = unpack_object_header_buffer(base, left, &type, sizep); if (!used) { type = OBJ_BAD; } else *curpos += used; return type; } int packed_object_info_detail(struct packed_git *p, off_t obj_offset, unsigned long *size, unsigned long *store_size, unsigned int *delta_chain_length, unsigned char *base_sha1) { struct pack_window *w_curs = NULL; off_t curpos; unsigned long dummy; unsigned char *next_sha1; enum object_type type; struct revindex_entry *revidx; *delta_chain_length = 0; curpos = obj_offset; type = unpack_object_header(p, &w_curs, &curpos, size); revidx = find_pack_revindex(p, obj_offset); *store_size = revidx[1].offset - obj_offset; for (;;) { switch (type) { default: die("pack %s contains unknown object type %d", p->pack_name, type); case OBJ_COMMIT: case OBJ_TREE: case OBJ_BLOB: case OBJ_TAG: unuse_pack(&w_curs); return type; case OBJ_OFS_DELTA: obj_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset); if (!obj_offset) die("pack %s contains bad delta base reference of type %s", p->pack_name, typename(type)); if (*delta_chain_length == 0) { revidx = find_pack_revindex(p, obj_offset); hashcpy(base_sha1, nth_packed_object_sha1(p, revidx->nr)); } break; case OBJ_REF_DELTA: next_sha1 = use_pack(p, &w_curs, curpos, NULL); if (*delta_chain_length == 0) hashcpy(base_sha1, next_sha1); obj_offset = find_pack_entry_one(next_sha1, p); break; } (*delta_chain_length)++; curpos = obj_offset; type = unpack_object_header(p, &w_curs, &curpos, &dummy); } } static int packed_object_info(struct packed_git *p, off_t obj_offset, unsigned long *sizep, int *rtype) { struct pack_window *w_curs = NULL; unsigned long size; off_t curpos = obj_offset; enum object_type type; type = unpack_object_header(p, &w_curs, &curpos, &size); if (rtype) *rtype = type; /* representation type */ switch (type) { case OBJ_OFS_DELTA: case OBJ_REF_DELTA: type = packed_delta_info(p, &w_curs, curpos, type, obj_offset, sizep); break; case OBJ_COMMIT: case OBJ_TREE: case OBJ_BLOB: case OBJ_TAG: if (sizep) *sizep = size; break; default: error("unknown object type %i at offset %"PRIuMAX" in %s", type, (uintmax_t)obj_offset, p->pack_name); type = OBJ_BAD; } 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; z_stream stream; unsigned char *buffer, *in; buffer = xmallocz(size); 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; } #define MAX_DELTA_CACHE (256) static size_t delta_base_cached; static struct delta_base_cache_lru_list { struct delta_base_cache_lru_list *prev; struct delta_base_cache_lru_list *next; } delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru }; static struct delta_base_cache_entry { struct delta_base_cache_lru_list lru; void *data; struct packed_git *p; off_t base_offset; unsigned long size; enum object_type type; } delta_base_cache[MAX_DELTA_CACHE]; static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset) { unsigned long hash; hash = (unsigned long)p + (unsigned long)base_offset; hash += (hash >> 8) + (hash >> 16); return hash % MAX_DELTA_CACHE; } static int in_delta_base_cache(struct packed_git *p, off_t base_offset) { unsigned long hash = pack_entry_hash(p, base_offset); struct delta_base_cache_entry *ent = delta_base_cache + hash; return (ent->data && ent->p == p && ent->base_offset == base_offset); } static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset, unsigned long *base_size, enum object_type *type, int keep_cache) { void *ret; unsigned long hash = pack_entry_hash(p, base_offset); struct delta_base_cache_entry *ent = delta_base_cache + hash; ret = ent->data; if (!ret || ent->p != p || ent->base_offset != base_offset) return unpack_entry(p, base_offset, type, base_size); if (!keep_cache) { ent->data = NULL; ent->lru.next->prev = ent->lru.prev; ent->lru.prev->next = ent->lru.next; delta_base_cached -= ent->size; } else { ret = xmemdupz(ent->data, ent->size); } *type = ent->type; *base_size = ent->size; return ret; } static inline void release_delta_base_cache(struct delta_base_cache_entry *ent) { if (ent->data) { free(ent->data); ent->data = NULL; ent->lru.next->prev = ent->lru.prev; ent->lru.prev->next = ent->lru.next; delta_base_cached -= ent->size; } } void clear_delta_base_cache(void) { unsigned long p; for (p = 0; p < MAX_DELTA_CACHE; p++) release_delta_base_cache(&delta_base_cache[p]); } static void add_delta_base_cache(struct packed_git *p, off_t base_offset, void *base, unsigned long base_size, enum object_type type) { unsigned long hash = pack_entry_hash(p, base_offset); struct delta_base_cache_entry *ent = delta_base_cache + hash; struct delta_base_cache_lru_list *lru; release_delta_base_cache(ent); delta_base_cached += base_size; for (lru = delta_base_cache_lru.next; delta_base_cached > delta_base_cache_limit && lru != &delta_base_cache_lru; lru = lru->next) { struct delta_base_cache_entry *f = (void *)lru; if (f->type == OBJ_BLOB) release_delta_base_cache(f); } for (lru = delta_base_cache_lru.next; delta_base_cached > delta_base_cache_limit && lru != &delta_base_cache_lru; lru = lru->next) { struct delta_base_cache_entry *f = (void *)lru; release_delta_base_cache(f); } ent->p = p; ent->base_offset = base_offset; ent->type = type; ent->data = base; ent->size = base_size; ent->lru.next = &delta_base_cache_lru; ent->lru.prev = delta_base_cache_lru.prev; delta_base_cache_lru.prev->next = &ent->lru; delta_base_cache_lru.prev = &ent->lru; } static void *read_object(const unsigned char *sha1, enum object_type *type, unsigned long *size); static void *unpack_delta_entry(struct packed_git *p, struct pack_window **w_curs, off_t curpos, unsigned long delta_size, off_t obj_offset, enum object_type *type, unsigned long *sizep) { void *delta_data, *result, *base; unsigned long base_size; off_t base_offset; 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); return NULL; } unuse_pack(w_curs); base = cache_or_unpack_entry(p, base_offset, &base_size, type, 0); 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, base_offset); if (!revidx) return NULL; 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)base_offset, p->pack_name); mark_bad_packed_object(p, base_sha1); base = read_object(base_sha1, type, &base_size); if (!base) return NULL; } 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); free(base); return NULL; } result = patch_delta(base, base_size, delta_data, delta_size, sizep); if (!result) die("failed to apply delta"); free(delta_data); add_delta_base_cache(p, base_offset, base, base_size, *type); return result; } int do_check_packed_object_crc; void *unpack_entry(struct packed_git *p, off_t obj_offset, enum object_type *type, unsigned long *sizep) { struct pack_window *w_curs = NULL; off_t curpos = obj_offset; void *data; if (do_check_packed_object_crc && p->index_version > 1) { struct revindex_entry *revidx = find_pack_revindex(p, obj_offset); unsigned long 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); unuse_pack(&w_curs); return NULL; } } *type = unpack_object_header(p, &w_curs, &curpos, sizep); switch (*type) { case OBJ_OFS_DELTA: case OBJ_REF_DELTA: data = unpack_delta_entry(p, &w_curs, curpos, *sizep, obj_offset, type, sizep); break; case OBJ_COMMIT: case OBJ_TREE: case OBJ_BLOB: case OBJ_TAG: data = unpack_compressed_entry(p, &w_curs, curpos, *sizep); break; default: data = NULL; error("unknown object type %i at offset %"PRIuMAX" in %s", *type, (uintmax_t)obj_offset, p->pack_name); } unuse_pack(&w_curs); return data; } const unsigned char *nth_packed_object_sha1(struct packed_git *p, uint32_t n) { const unsigned char *index = p->index_data; if (!index) { if (open_pack_index(p)) return NULL; index = p->index_data; } if (n >= p->num_objects) return NULL; index += 4 * 256; if (p->index_version == 1) { return index + 24 * n + 4; } else { index += 8; return index + 20 * n; } } 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; 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) { const uint32_t *level1_ofs = p->index_data; const unsigned char *index = p->index_data; unsigned hi, lo, stride; static int use_lookup = -1; static int debug_lookup = -1; if (debug_lookup < 0) debug_lookup = !!getenv("GIT_DEBUG_LOOKUP"); if (!index) { if (open_pack_index(p)) return 0; level1_ofs = p->index_data; index = p->index_data; } if (p->index_version > 1) { level1_ofs += 2; index += 8; } index += 4 * 256; hi = ntohl(level1_ofs[*sha1]); lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1])); if (p->index_version > 1) { stride = 20; } else { stride = 24; index += 4; } if (debug_lookup) printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n", sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects); if (use_lookup < 0) use_lookup = !!getenv("GIT_USE_LOOKUP"); if (use_lookup) { int pos = sha1_entry_pos(index, stride, 0, lo, hi, p->num_objects, sha1); if (pos < 0) return 0; return nth_packed_object_offset(p, pos); } do { unsigned mi = (lo + hi) / 2; int cmp = hashcmp(index + mi * stride, sha1); if (debug_lookup) printf("lo %u hi %u rg %u mi %u\n", lo, hi, hi - lo, mi); if (!cmp) return nth_packed_object_offset(p, mi); if (cmp > 0) hi = mi; else lo = mi+1; } while (lo < hi); return 0; } static int is_pack_valid(struct packed_git *p) { /* An already open pack is known to be valid. */ if (p->pack_fd != -1) return 1; /* If the pack has one window completely covering the * file size, the pack is known to be valid even if * the descriptor is not currently open. */ if (p->windows) { struct pack_window *w = p->windows; if (!w->offset && w->len == p->pack_size) return 1; } /* Force the pack to open to prove its valid. */ return !open_packed_git(p); } static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e) { static struct packed_git *last_found = (void *)1; struct packed_git *p; off_t offset; prepare_packed_git(); if (!packed_git) return 0; p = (last_found == (void *)1) ? packed_git : last_found; do { if (p->num_bad_objects) { unsigned i; for (i = 0; i < p->num_bad_objects; i++) if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i)) goto next; } offset = find_pack_entry_one(sha1, p); if (offset) { /* * We are about to tell the caller where they can * locate the requested object. We better make * sure the packfile is still here and can be * accessed before supplying that answer, as * it may have been deleted since the index * was loaded! */ if (!is_pack_valid(p)) { error("packfile %s cannot be accessed", p->pack_name); goto next; } e->offset = offset; e->p = p; hashcpy(e->sha1, sha1); last_found = p; return 1; } next: if (p == last_found) p = packed_git; else p = p->next; if (p == last_found) p = p->next; } while (p); return 0; } struct packed_git *find_sha1_pack(const unsigned char *sha1, struct packed_git *packs) { struct packed_git *p; for (p = packs; p; p = p->next) { if (find_pack_entry_one(sha1, p)) return p; } return NULL; } static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *sizep) { int status; unsigned long mapsize, size; void *map; z_stream stream; char hdr[32]; map = map_sha1_file(sha1, &mapsize); if (!map) return error("unable to find %s", sha1_to_hex(sha1)); if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) status = error("unable to unpack %s header", sha1_to_hex(sha1)); else if ((status = parse_sha1_header(hdr, &size)) < 0) status = error("unable to parse %s header", sha1_to_hex(sha1)); else if (sizep) *sizep = size; git_inflate_end(&stream); munmap(map, mapsize); return status; } /* returns enum object_type or negative */ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi) { struct cached_object *co; struct pack_entry e; int status, rtype; co = find_cached_object(sha1); if (co) { if (oi->sizep) *(oi->sizep) = co->size; oi->whence = OI_CACHED; return co->type; } if (!find_pack_entry(sha1, &e)) { /* Most likely it's a loose object. */ status = sha1_loose_object_info(sha1, oi->sizep); if (status >= 0) { oi->whence = OI_LOOSE; return status; } /* Not a loose object; someone else may have just packed it. */ reprepare_packed_git(); if (!find_pack_entry(sha1, &e)) return status; } status = packed_object_info(e.p, e.offset, oi->sizep, &rtype); if (status < 0) { mark_bad_packed_object(e.p, sha1); status = sha1_object_info_extended(sha1, oi); } else if (in_delta_base_cache(e.p, e.offset)) { oi->whence = OI_DBCACHED; } else { oi->whence = OI_PACKED; oi->u.packed.offset = e.offset; oi->u.packed.pack = e.p; oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA || rtype == OBJ_OFS_DELTA); } return status; } int sha1_object_info(const unsigned char *sha1, unsigned long *sizep) { struct object_info oi; oi.sizep = sizep; return sha1_object_info_extended(sha1, &oi); } static void *read_packed_sha1(const unsigned char *sha1, enum object_type *type, unsigned long *size) { struct pack_entry e; void *data; if (!find_pack_entry(sha1, &e)) return NULL; data = cache_or_unpack_entry(e.p, e.offset, size, type, 1); if (!data) { /* * We're probably in deep shit, but let's try to fetch * the required object anyway from another pack or loose. * This should happen only in the presence of a corrupted * pack, and is better than failing outright. */ error("failed to read object %s at offset %"PRIuMAX" from %s", sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name); mark_bad_packed_object(e.p, sha1); data = read_object(sha1, type, size); } return data; } int pretend_sha1_file(void *buf, unsigned long len, enum object_type type, unsigned char *sha1) { struct cached_object *co; hash_sha1_file(buf, len, typename(type), sha1); if (has_sha1_file(sha1) || find_cached_object(sha1)) return 0; if (cached_object_alloc <= cached_object_nr) { cached_object_alloc = alloc_nr(cached_object_alloc); cached_objects = xrealloc(cached_objects, sizeof(*cached_objects) * cached_object_alloc); } co = &cached_objects[cached_object_nr++]; co->size = len; co->type = type; co->buf = xmalloc(len); memcpy(co->buf, buf, len); hashcpy(co->sha1, sha1); return 0; } static void *read_object(const unsigned char *sha1, enum object_type *type, unsigned long *size) { unsigned long mapsize; void *map, *buf; struct cached_object *co; co = find_cached_object(sha1); if (co) { *type = co->type; *size = co->size; return xmemdupz(co->buf, co->size); } buf = read_packed_sha1(sha1, type, size); if (buf) return buf; map = map_sha1_file(sha1, &mapsize); if (map) { buf = unpack_sha1_file(map, mapsize, type, size, sha1); munmap(map, mapsize); return buf; } reprepare_packed_git(); return read_packed_sha1(sha1, type, size); } /* * This function dies on corrupt objects; the callers who want to * deal with them should arrange to call read_object() and give error * messages themselves. */ void *read_sha1_file_extended(const unsigned char *sha1, enum object_type *type, unsigned long *size, unsigned flag) { void *data; char *path; const struct packed_git *p; const unsigned char *repl = (flag & READ_SHA1_FILE_REPLACE) ? lookup_replace_object(sha1) : sha1; errno = 0; data = read_object(repl, type, size); if (data) return data; if (errno && errno != ENOENT) die_errno("failed to read object %s", sha1_to_hex(sha1)); /* die if we replaced an object with one that does not exist */ if (repl != sha1) die("replacement %s not found for %s", sha1_to_hex(repl), sha1_to_hex(sha1)); if (has_loose_object(repl)) { path = sha1_file_name(sha1); die("loose object %s (stored in %s) is corrupt", sha1_to_hex(repl), path); } if ((p = has_packed_and_bad(repl)) != NULL) die("packed object %s (stored in %s) is corrupt", sha1_to_hex(repl), p->pack_name); return NULL; } void *read_object_with_reference(const unsigned char *sha1, const char *required_type_name, unsigned long *size, unsigned char *actual_sha1_return) { enum object_type type, required_type; void *buffer; unsigned long isize; unsigned char actual_sha1[20]; required_type = type_from_string(required_type_name); hashcpy(actual_sha1, sha1); while (1) { int ref_length = -1; const char *ref_type = NULL; buffer = read_sha1_file(actual_sha1, &type, &isize); if (!buffer) return NULL; if (type == required_type) { *size = isize; if (actual_sha1_return) hashcpy(actual_sha1_return, actual_sha1); return buffer; } /* Handle references */ else if (type == OBJ_COMMIT) ref_type = "tree "; else if (type == OBJ_TAG) ref_type = "object "; else { free(buffer); return NULL; } ref_length = strlen(ref_type); if (ref_length + 40 > isize || memcmp(buffer, ref_type, ref_length) || get_sha1_hex((char *) buffer + ref_length, actual_sha1)) { free(buffer); return NULL; } free(buffer); /* Now we have the ID of the referred-to object in * actual_sha1. Check again. */ } } static void write_sha1_file_prepare(const void *buf, unsigned long len, const char *type, unsigned char *sha1, char *hdr, int *hdrlen) { git_SHA_CTX c; /* Generate the header */ *hdrlen = sprintf(hdr, "%s %lu", type, len)+1; /* Sha1.. */ git_SHA1_Init(&c); git_SHA1_Update(&c, hdr, *hdrlen); git_SHA1_Update(&c, buf, len); git_SHA1_Final(sha1, &c); } /* * Move the just written object into its final resting place. * NEEDSWORK: this should be renamed to finalize_temp_file() as * "moving" is only a part of what it does, when no patch between * master to pu changes the call sites of this function. */ int move_temp_to_file(const char *tmpfile, const char *filename) { int ret = 0; if (object_creation_mode == OBJECT_CREATION_USES_RENAMES) goto try_rename; else if (link(tmpfile, filename)) ret = errno; /* * Coda hack - coda doesn't like cross-directory links, * so we fall back to a rename, which will mean that it * won't be able to check collisions, but that's not a * big deal. * * The same holds for FAT formatted media. * * When this succeeds, we just return. We have nothing * left to unlink. */ if (ret && ret != EEXIST) { try_rename: if (!rename(tmpfile, filename)) goto out; ret = errno; } unlink_or_warn(tmpfile); if (ret) { if (ret != EEXIST) { return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret)); } /* FIXME!!! Collision check here ? */ } out: if (adjust_shared_perm(filename)) return error("unable to set permission to '%s'", filename); return 0; } static int write_buffer(int fd, const void *buf, size_t len) { if (write_in_full(fd, buf, len) < 0) return error("file write error (%s)", strerror(errno)); return 0; } int hash_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1) { char hdr[32]; int hdrlen; write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen); return 0; } /* Finalize a file on disk, and close it. */ static void close_sha1_file(int fd) { if (fsync_object_files) fsync_or_die(fd, "sha1 file"); if (close(fd) != 0) die_errno("error when closing sha1 file"); } /* Size of directory component, including the ending '/' */ static inline int directory_size(const char *filename) { const char *s = strrchr(filename, '/'); if (!s) return 0; return s - filename + 1; } /* * This creates a temporary file in the same directory as the final * 'filename' * * We want to avoid cross-directory filename renames, because those * can have problems on various filesystems (FAT, NFS, Coda). */ static int create_tmpfile(char *buffer, size_t bufsiz, const char *filename) { int fd, dirlen = directory_size(filename); if (dirlen + 20 > bufsiz) { errno = ENAMETOOLONG; return -1; } memcpy(buffer, filename, dirlen); strcpy(buffer + dirlen, "tmp_obj_XXXXXX"); fd = git_mkstemp_mode(buffer, 0444); if (fd < 0 && dirlen && errno == ENOENT) { /* Make sure the directory exists */ memcpy(buffer, filename, dirlen); buffer[dirlen-1] = 0; if (mkdir(buffer, 0777) || adjust_shared_perm(buffer)) return -1; /* Try again */ strcpy(buffer + dirlen - 1, "/tmp_obj_XXXXXX"); fd = git_mkstemp_mode(buffer, 0444); } return fd; } static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen, const void *buf, unsigned long len, time_t mtime) { int fd, ret; unsigned char compressed[4096]; z_stream stream; git_SHA_CTX c; unsigned char parano_sha1[20]; char *filename; static char tmpfile[PATH_MAX]; filename = sha1_file_name(sha1); fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename); if (fd < 0) { if (errno == EACCES) return error("insufficient permission for adding an object to repository database %s\n", get_object_directory()); else return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno)); } /* Set it up */ memset(&stream, 0, sizeof(stream)); deflateInit(&stream, zlib_compression_level); stream.next_out = compressed; stream.avail_out = sizeof(compressed); git_SHA1_Init(&c); /* First header.. */ stream.next_in = (unsigned char *)hdr; stream.avail_in = hdrlen; while (deflate(&stream, 0) == Z_OK) /* nothing */; git_SHA1_Update(&c, hdr, hdrlen); /* Then the data itself.. */ stream.next_in = (void *)buf; stream.avail_in = len; do { unsigned char *in0 = stream.next_in; ret = deflate(&stream, Z_FINISH); git_SHA1_Update(&c, in0, stream.next_in - in0); if (write_buffer(fd, compressed, stream.next_out - compressed) < 0) die("unable to write sha1 file"); stream.next_out = compressed; stream.avail_out = sizeof(compressed); } while (ret == Z_OK); if (ret != Z_STREAM_END) die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret); ret = deflateEnd(&stream); if (ret != Z_OK) die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret); git_SHA1_Final(parano_sha1, &c); if (hashcmp(sha1, parano_sha1) != 0) die("confused by unstable object source data for %s", sha1_to_hex(sha1)); close_sha1_file(fd); if (mtime) { struct utimbuf utb; utb.actime = mtime; utb.modtime = mtime; if (utime(tmpfile, &utb) < 0) warning("failed utime() on %s: %s", tmpfile, strerror(errno)); } return move_temp_to_file(tmpfile, filename); } int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *returnsha1) { unsigned char sha1[20]; char hdr[32]; int hdrlen; /* Normally if we have it in the pack then we do not bother writing * it out into .git/objects/??/?{38} file. */ write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen); if (returnsha1) hashcpy(returnsha1, sha1); if (has_sha1_file(sha1)) return 0; return write_loose_object(sha1, hdr, hdrlen, buf, len, 0); } int force_object_loose(const unsigned char *sha1, time_t mtime) { void *buf; unsigned long len; enum object_type type; char hdr[32]; int hdrlen; int ret; if (has_loose_object(sha1)) return 0; buf = read_packed_sha1(sha1, &type, &len); if (!buf) return error("cannot read sha1_file for %s", sha1_to_hex(sha1)); hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1; ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime); free(buf); return ret; } int has_pack_index(const unsigned char *sha1) { struct stat st; if (stat(sha1_pack_index_name(sha1), &st)) return 0; return 1; } int has_sha1_pack(const unsigned char *sha1) { struct pack_entry e; return find_pack_entry(sha1, &e); } int has_sha1_file(const unsigned char *sha1) { struct pack_entry e; if (find_pack_entry(sha1, &e)) return 1; return has_loose_object(sha1); } static void check_tree(const void *buf, size_t size) { struct tree_desc desc; struct name_entry entry; init_tree_desc(&desc, buf, size); while (tree_entry(&desc, &entry)) /* do nothing * tree_entry() will die() on malformed entries */ ; } static void check_commit(const void *buf, size_t size) { struct commit c; memset(&c, 0, sizeof(c)); if (parse_commit_buffer(&c, buf, size)) die("corrupt commit"); } static void check_tag(const void *buf, size_t size) { struct tag t; memset(&t, 0, sizeof(t)); if (parse_tag_buffer(&t, buf, size)) die("corrupt tag"); } static int index_mem(unsigned char *sha1, void *buf, size_t size, enum object_type type, const char *path, unsigned flags) { int ret, re_allocated = 0; int write_object = flags & HASH_WRITE_OBJECT; if (!type) type = OBJ_BLOB; /* * Convert blobs to git internal format */ if ((type == OBJ_BLOB) && path) { struct strbuf nbuf = STRBUF_INIT; if (convert_to_git(path, buf, size, &nbuf, write_object ? safe_crlf : 0)) { buf = strbuf_detach(&nbuf, &size); re_allocated = 1; } } if (flags & HASH_FORMAT_CHECK) { if (type == OBJ_TREE) check_tree(buf, size); if (type == OBJ_COMMIT) check_commit(buf, size); if (type == OBJ_TAG) check_tag(buf, size); } if (write_object) ret = write_sha1_file(buf, size, typename(type), sha1); else ret = hash_sha1_file(buf, size, typename(type), sha1); if (re_allocated) free(buf); return ret; } static int index_pipe(unsigned char *sha1, int fd, enum object_type type, const char *path, unsigned flags) { struct strbuf sbuf = STRBUF_INIT; int ret; if (strbuf_read(&sbuf, fd, 4096) >= 0) ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags); else ret = -1; strbuf_release(&sbuf); return ret; } #define SMALL_FILE_SIZE (32*1024) static int index_core(unsigned char *sha1, int fd, size_t size, enum object_type type, const char *path, unsigned flags) { int ret; if (!size) { ret = index_mem(sha1, NULL, size, type, path, flags); } else if (size <= SMALL_FILE_SIZE) { char *buf = xmalloc(size); if (size == read_in_full(fd, buf, size)) ret = index_mem(sha1, buf, size, type, path, flags); else ret = error("short read %s", strerror(errno)); free(buf); } else { void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0); ret = index_mem(sha1, buf, size, type, path, flags); munmap(buf, size); } return ret; } /* * This creates one packfile per large blob, because the caller * immediately wants the result sha1, and fast-import can report the * object name via marks mechanism only by closing the created * packfile. * * This also bypasses the usual "convert-to-git" dance, and that is on * purpose. We could write a streaming version of the converting * functions and insert that before feeding the data to fast-import * (or equivalent in-core API described above), but the primary * motivation for trying to stream from the working tree file and to * avoid mmaping it in core is to deal with large binary blobs, and * by definition they do _not_ want to get any conversion. */ static int index_stream(unsigned char *sha1, int fd, size_t size, enum object_type type, const char *path, unsigned flags) { struct child_process fast_import; char export_marks[512]; const char *argv[] = { "fast-import", "--quiet", export_marks, NULL }; char tmpfile[512]; char fast_import_cmd[512]; char buf[512]; int len, tmpfd; strcpy(tmpfile, git_path("hashstream_XXXXXX")); tmpfd = git_mkstemp_mode(tmpfile, 0600); if (tmpfd < 0) die_errno("cannot create tempfile: %s", tmpfile); if (close(tmpfd)) die_errno("cannot close tempfile: %s", tmpfile); sprintf(export_marks, "--export-marks=%s", tmpfile); memset(&fast_import, 0, sizeof(fast_import)); fast_import.in = -1; fast_import.argv = argv; fast_import.git_cmd = 1; if (start_command(&fast_import)) die_errno("index-stream: git fast-import failed"); len = sprintf(fast_import_cmd, "blob\nmark :1\ndata %lu\n", (unsigned long) size); write_or_whine(fast_import.in, fast_import_cmd, len, "index-stream: feeding fast-import"); while (size) { char buf[10240]; size_t sz = size < sizeof(buf) ? size : sizeof(buf); ssize_t actual; actual = read_in_full(fd, buf, sz); if (actual < 0) die_errno("index-stream: reading input"); if (write_in_full(fast_import.in, buf, actual) != actual) die_errno("index-stream: feeding fast-import"); size -= actual; } if (close(fast_import.in)) die_errno("index-stream: closing fast-import"); if (finish_command(&fast_import)) die_errno("index-stream: finishing fast-import"); tmpfd = open(tmpfile, O_RDONLY); if (tmpfd < 0) die_errno("index-stream: cannot open fast-import mark"); len = read(tmpfd, buf, sizeof(buf)); if (len < 0) die_errno("index-stream: reading fast-import mark"); if (close(tmpfd) < 0) die_errno("index-stream: closing fast-import mark"); if (unlink(tmpfile)) die_errno("index-stream: unlinking fast-import mark"); if (len != 44 || memcmp(":1 ", buf, 3) || get_sha1_hex(buf + 3, sha1)) die_errno("index-stream: unexpected fast-import mark: <%s>", buf); return 0; } int index_fd(unsigned char *sha1, int fd, struct stat *st, enum object_type type, const char *path, unsigned flags) { int ret; size_t size = xsize_t(st->st_size); if (!S_ISREG(st->st_mode)) ret = index_pipe(sha1, fd, type, path, flags); else if (size <= big_file_threshold || type != OBJ_BLOB) ret = index_core(sha1, fd, size, type, path, flags); else ret = index_stream(sha1, fd, size, type, path, flags); close(fd); return ret; } int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags) { int fd; struct strbuf sb = STRBUF_INIT; switch (st->st_mode & S_IFMT) { case S_IFREG: fd = open(path, O_RDONLY); if (fd < 0) return error("open(\"%s\"): %s", path, strerror(errno)); if (index_fd(sha1, fd, st, OBJ_BLOB, path, flags) < 0) return error("%s: failed to insert into database", path); break; case S_IFLNK: if (strbuf_readlink(&sb, path, st->st_size)) { char *errstr = strerror(errno); return error("readlink(\"%s\"): %s", path, errstr); } if (!(flags & HASH_WRITE_OBJECT)) hash_sha1_file(sb.buf, sb.len, blob_type, sha1); else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1)) return error("%s: failed to insert into database", path); strbuf_release(&sb); break; case S_IFDIR: return resolve_gitlink_ref(path, "HEAD", sha1); default: return error("%s: unsupported file type", path); } return 0; } int read_pack_header(int fd, struct pack_header *header) { if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header)) /* "eof before pack header was fully read" */ return PH_ERROR_EOF; if (header->hdr_signature != htonl(PACK_SIGNATURE)) /* "protocol error (pack signature mismatch detected)" */ return PH_ERROR_PACK_SIGNATURE; if (!pack_version_ok(header->hdr_version)) /* "protocol error (pack version unsupported)" */ return PH_ERROR_PROTOCOL; return 0; } void assert_sha1_type(const unsigned char *sha1, enum object_type expect) { enum object_type type = sha1_object_info(sha1, NULL); if (type < 0) die("%s is not a valid object", sha1_to_hex(sha1)); if (type != expect) die("%s is not a valid '%s' object", sha1_to_hex(sha1), typename(expect)); }