diff options
Diffstat (limited to 'sha1_file.c')
| -rw-r--r-- | sha1_file.c | 3045 |
1 files changed, 3045 insertions, 0 deletions
diff --git a/sha1_file.c b/sha1_file.c new file mode 100644 index 0000000000..67e815b2db --- /dev/null +++ b/sha1_file.c @@ -0,0 +1,3045 @@ +/* + * 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 "string-list.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" +#include "bulk-checkin.h" +#include "streaming.h" +#include "dir.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 packed_git *last_found_pack; + +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)) { + if (errno == EEXIST && + !stat(path, &st) && S_ISDIR(st.st_mode)) { + ; /* somebody created it since we checked */ + } else { + *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 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, const char *relative_base, int depth) +{ + const char *objdir = get_object_directory(); + struct alternate_object_database *ent; + struct alternate_object_database *alt; + int pfxlen, entlen; + struct strbuf pathbuf = STRBUF_INIT; + + if (!is_absolute_path(entry) && relative_base) { + strbuf_addstr(&pathbuf, real_path(relative_base)); + strbuf_addch(&pathbuf, '/'); + } + strbuf_addstr(&pathbuf, entry); + + normalize_path_copy(pathbuf.buf, pathbuf.buf); + + pfxlen = strlen(pathbuf.buf); + + /* + * The trailing slash after the directory name is given by + * this function at the end. Remove duplicates. + */ + while (pfxlen && pathbuf.buf[pfxlen-1] == '/') + pfxlen -= 1; + + entlen = pfxlen + 43; /* '/' + 2 hex + '/' + 38 hex + NUL */ + ent = xmalloc(sizeof(*ent) + entlen); + memcpy(ent->base, pathbuf.buf, pfxlen); + strbuf_release(&pathbuf); + + 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 (!strcmp(ent->base, objdir)) { + 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, int len, int sep, + const char *relative_base, int depth) +{ + struct string_list entries = STRING_LIST_INIT_NODUP; + char *alt_copy; + int i; + + if (depth > 5) { + error("%s: ignoring alternate object stores, nesting too deep.", + relative_base); + return; + } + + alt_copy = xmemdupz(alt, len); + string_list_split_in_place(&entries, alt_copy, sep, -1); + for (i = 0; i < entries.nr; i++) { + const char *entry = entries.items[i].string; + if (entry[0] == '\0' || entry[0] == '#') + continue; + if (!is_absolute_path(entry) && depth) { + error("%s: ignoring relative alternate object store %s", + relative_base, entry); + } else { + link_alt_odb_entry(entry, relative_base, depth); + } + } + string_list_clear(&entries, 0); + free(alt_copy); +} + +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, 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\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, 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, 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; + if (last_found_pack == p) + last_found_pack = NULL; + free(p); + return; + } + pp = &p->next; + } +} + +static unsigned int get_max_fd_limit(void) +{ +#ifdef RLIMIT_NOFILE + struct rlimit lim; + + if (getrlimit(RLIMIT_NOFILE, &lim)) + die_errno("cannot get RLIMIT_NOFILE"); + + return lim.rlim_cur; +#elif defined(_SC_OPEN_MAX) + return sysconf(_SC_OPEN_MAX); +#elif defined(OPEN_MAX) + return OPEN_MAX; +#else + return 1; /* see the caller ;-) */ +#endif +} + +/* + * 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) { + unsigned int max_fds = get_max_fd_limit(); + + /* 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 long *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; +} + +void (*report_garbage)(const char *desc, const char *path); + +static void report_helper(const struct string_list *list, + int seen_bits, int first, int last) +{ + const char *msg; + switch (seen_bits) { + case 0: + msg = "no corresponding .idx nor .pack"; + break; + case 1: + msg = "no corresponding .idx"; + break; + case 2: + msg = "no corresponding .pack"; + break; + default: + return; + } + for (; first < last; first++) + report_garbage(msg, list->items[first].string); +} + +static void report_pack_garbage(struct string_list *list) +{ + int i, baselen = -1, first = 0, seen_bits = 0; + + if (!report_garbage) + return; + + sort_string_list(list); + + for (i = 0; i < list->nr; i++) { + const char *path = list->items[i].string; + if (baselen != -1 && + strncmp(path, list->items[first].string, baselen)) { + report_helper(list, seen_bits, first, i); + baselen = -1; + seen_bits = 0; + } + if (baselen == -1) { + const char *dot = strrchr(path, '.'); + if (!dot) { + report_garbage("garbage found", path); + continue; + } + baselen = dot - path + 1; + first = i; + } + if (!strcmp(path + baselen, "pack")) + seen_bits |= 1; + else if (!strcmp(path + baselen, "idx")) + seen_bits |= 2; + } + report_helper(list, seen_bits, first, list->nr); +} + +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; + struct string_list garbage = STRING_LIST_INIT_DUP; + + 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 (len + namelen + 1 > sizeof(path)) { + if (report_garbage) { + struct strbuf sb = STRBUF_INIT; + strbuf_addf(&sb, "%.*s/%s", len - 1, path, de->d_name); + report_garbage("path too long", sb.buf); + strbuf_release(&sb); + } + continue; + } + + if (is_dot_or_dotdot(de->d_name)) + continue; + + strcpy(path + len, de->d_name); + + if (has_extension(de->d_name, ".idx")) { + /* Don't reopen a pack we already have. */ + for (p = packed_git; p; p = p->next) { + if (!memcmp(path, p->pack_name, len + namelen - 4)) + break; + } + if (p == NULL && + /* + * 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)) != NULL) + install_packed_git(p); + } + + if (!report_garbage) + continue; + + if (has_extension(de->d_name, ".idx") || + has_extension(de->d_name, ".pack") || + has_extension(de->d_name, ".keep")) + string_list_append(&garbage, path); + else + report_garbage("garbage found", path); + } + closedir(dir); + report_pack_garbage(&garbage); + string_list_clear(&garbage, 0); +} + +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; +} + +/* + * With an in-core object data in "map", rehash it to make sure the + * object name actually matches "sha1" to detect object corruption. + * With "map" == NULL, try reading the object named with "sha1" using + * the streaming interface and rehash it to do the same. + */ +int check_sha1_signature(const unsigned char *sha1, void *map, + unsigned long size, const char *type) +{ + unsigned char real_sha1[20]; + enum object_type obj_type; + struct git_istream *st; + git_SHA_CTX c; + char hdr[32]; + int hdrlen; + + if (map) { + hash_sha1_file(map, size, type, real_sha1); + return hashcmp(sha1, real_sha1) ? -1 : 0; + } + + st = open_istream(sha1, &obj_type, &size, NULL); + if (!st) + return -1; + + /* Generate the header */ + hdrlen = sprintf(hdr, "%s %lu", typename(obj_type), size) + 1; + + /* Sha1.. */ + git_SHA1_Init(&c); + git_SHA1_Update(&c, hdr, hdrlen); + for (;;) { + char buf[1024 * 16]; + ssize_t readlen = read_istream(st, buf, sizeof(buf)); + + if (readlen < 0) { + close_istream(st); + return -1; + } + if (!readlen) + break; + git_SHA1_Update(&c, buf, readlen); + } + git_SHA1_Final(real_sha1, &c); + close_istream(st); + 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); + if (!*size) { + /* mmap() is forbidden on empty files */ + error("object file %s is empty", sha1_file_name(sha1)); + return NULL; + } + 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; + + /* + * We must determine if the buffer contains the standard + * zlib-deflated stream or the experimental format based + * on the in-pack object format. Compare the header byte + * for each format: + * + * RFC1950 zlib w/ deflate : 0www1000 : 0 <= www <= 7 + * Experimental pack-based : Stttssss : ttt = 1,2,3,4 + * + * If bit 7 is clear and bits 0-3 equal 8, the buffer MUST be + * in standard loose-object format, UNLESS it is a Git-pack + * format object *exactly* 8 bytes in size when inflated. + * + * However, RFC1950 also specifies that the 1st 16-bit word + * must be divisible by 31 - this checksum tells us our buffer + * is in the standard format, giving a false positive only if + * the 1st word of the Git-pack format object happens to be + * divisible by 31, ie: + * ((byte0 * 256) + byte1) % 31 = 0 + * => 0ttt10000www1000 % 31 = 0 + * + * As it happens, this case can only arise for www=3 & ttt=1 + * - ie, a Commit object, which would have to be 8 bytes in + * size. As no Commit can be that small, we find that the + * combination of these two criteria (bitmask & checksum) + * can always correctly determine the buffer format. + */ + word = (map[0] << 8) + map[1]; + if ((map[0] & 0x8F) == 0x08 && !(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"); + size = used = 0; + break; + } + c = buf[used++]; + size += (c & 0x7f) << shift; + shift += 7; + } + *sizep = size; + return used; +} + +int unpack_sha1_header(git_zstream *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(git_zstream *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; + git_zstream 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; + git_zstream 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; +} + +int unpack_object_header(struct packed_git *p, + struct pack_window **w_curs, + off_t *curpos, + unsigned long *sizep) +{ + unsigned char *base; + unsigned long 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; +} + +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 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; + 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; + + type = unpack_object_header(p, &w_curs, &curpos, &size); + + if (rtype) + *rtype = type; /* representation type */ + + if (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; + } + *sizep = get_size_from_delta(p, &w_curs, tmp_pos); + if (*sizep == 0) { + type = OBJ_BAD; + goto out; + } + } else { + *sizep = size; + } + } + + while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) { + off_t base_offset; + /* 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); + poi_stack = xmalloc(sizeof(off_t)*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); + unuse_pack(&w_curs); + 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 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(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 struct delta_base_cache_entry * +get_delta_base_cache_entry(struct packed_git *p, off_t base_offset) +{ + unsigned long hash = pack_entry_hash(p, base_offset); + return delta_base_cache + hash; +} + +static int eq_delta_base_cache_entry(struct delta_base_cache_entry *ent, + struct packed_git *p, off_t base_offset) +{ + return (ent->data && ent->p == p && ent->base_offset == base_offset); +} + +static int in_delta_base_cache(struct packed_git *p, off_t base_offset) +{ + struct delta_base_cache_entry *ent; + ent = get_delta_base_cache_entry(p, base_offset); + return eq_delta_base_cache_entry(ent, p, base_offset); +} + +static void clear_delta_base_cache_entry(struct delta_base_cache_entry *ent) +{ + ent->data = NULL; + ent->lru.next->prev = ent->lru.prev; + ent->lru.prev->next = ent->lru.next; + delta_base_cached -= ent->size; +} + +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) +{ + struct delta_base_cache_entry *ent; + void *ret; + + ent = get_delta_base_cache_entry(p, base_offset); + + if (!eq_delta_base_cache_entry(ent, p, base_offset)) + return unpack_entry(p, base_offset, type, base_size); + + ret = ent->data; + + if (!keep_cache) + clear_delta_base_cache_entry(ent); + 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 write_pack_access_log(struct packed_git *p, off_t obj_offset) +{ + static FILE *log_file; + + if (!log_file) { + log_file = fopen(log_pack_access, "w"); + if (!log_file) { + error("cannot open pack access log '%s' for writing: %s", + log_pack_access, strerror(errno)); + log_pack_access = NULL; + return; + } + } + fprintf(log_file, "%s %"PRIuMAX"\n", + p->pack_name, (uintmax_t)obj_offset); + fflush(log_file); +} + +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; + + if (log_pack_access) + 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; + + 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; + } + } + + ent = get_delta_base_cache_entry(p, curpos); + if (eq_delta_base_cache_entry(ent, p, curpos)) { + type = ent->type; + data = ent->data; + size = ent->size; + clear_delta_base_cache_entry(ent); + base_from_cache = 1; + break; + } + + 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); + delta_stack = xmalloc(sizeof(*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 in 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; + 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); + } + } + + 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; + continue; + } + + data = patch_delta(base, base_size, + delta_data, delta_size, + &size); + if (!data) + die("failed to apply delta"); + + free (delta_data); + } + + *final_type = type; + *final_size = size; + + 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; +} + +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 fill_pack_entry(const unsigned char *sha1, + struct pack_entry *e, + struct packed_git *p) +{ + off_t offset; + + 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)) + return 0; + } + + offset = find_pack_entry_one(sha1, p); + if (!offset) + return 0; + + /* + * 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)) { + warning("packfile %s cannot be accessed", p->pack_name); + return 0; + } + e->offset = offset; + e->p = p; + hashcpy(e->sha1, sha1); + return 1; +} + +static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e) +{ + struct packed_git *p; + + prepare_packed_git(); + if (!packed_git) + return 0; + + if (last_found_pack && fill_pack_entry(sha1, e, last_found_pack)) + return 1; + + for (p = packed_git; p; p = p->next) { + if (p == last_found_pack || !fill_pack_entry(sha1, e, p)) + continue; + + last_found_pack = p; + return 1; + } + 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; + git_zstream 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", 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]; + git_zstream stream; + git_SHA_CTX c; + unsigned char parano_sha1[20]; + char *filename; + static char tmp_file[PATH_MAX]; + + filename = sha1_file_name(sha1); + fd = create_tmpfile(tmp_file, sizeof(tmp_file), filename); + if (fd < 0) { + if (errno == EACCES) + return error("insufficient permission for adding an object to repository database %s", get_object_directory()); + else + return error("unable to create temporary file: %s", strerror(errno)); + } + + /* Set it up */ + memset(&stream, 0, sizeof(stream)); + git_deflate_init(&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 (git_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 = git_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 = git_deflate_end_gently(&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(tmp_file, &utb) < 0) + warning("failed utime() on %s: %s", + tmp_file, strerror(errno)); + } + + return move_temp_to_file(tmp_file, 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 : SAFE_CRLF_FALSE)) { + 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 unless bulk-checkin + * machinery is "plugged". + * + * 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). However, that is + * somewhat complicated, as we do not know the size of the filter + * result, which we need to know beforehand when writing a git object. + * Since 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, they generally do not want to get any conversion, and + * callers should avoid this code path when filters are requested. + */ +static int index_stream(unsigned char *sha1, int fd, size_t size, + enum object_type type, const char *path, + unsigned flags) +{ + return index_bulk_checkin(sha1, fd, size, type, path, flags); +} + +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 || + (path && would_convert_to_git(path, NULL, 0, 0))) + 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)); +} |