#include "../cache.h" #include "../refs.h" #include "refs-internal.h" #include "ref-cache.h" #include "../iterator.h" #include "../dir-iterator.h" #include "../lockfile.h" #include "../object.h" #include "../dir.h" struct ref_lock { char *ref_name; struct lock_file *lk; struct object_id old_oid; }; /* * Return true if refname, which has the specified oid and flags, can * be resolved to an object in the database. If the referred-to object * does not exist, emit a warning and return false. */ static int ref_resolves_to_object(const char *refname, const struct object_id *oid, unsigned int flags) { if (flags & REF_ISBROKEN) return 0; if (!has_sha1_file(oid->hash)) { error("%s does not point to a valid object!", refname); return 0; } return 1; } struct packed_ref_cache { struct ref_cache *cache; /* * Count of references to the data structure in this instance, * including the pointer from files_ref_store::packed if any. * The data will not be freed as long as the reference count * is nonzero. */ unsigned int referrers; /* The metadata from when this packed-refs cache was read */ struct stat_validity validity; }; /* * Future: need to be in "struct repository" * when doing a full libification. */ struct files_ref_store { struct ref_store base; unsigned int store_flags; char *gitdir; char *gitcommondir; char *packed_refs_path; struct ref_cache *loose; struct packed_ref_cache *packed; /* * Lock used for the "packed-refs" file. Note that this (and * thus the enclosing `files_ref_store`) must not be freed. */ struct lock_file packed_refs_lock; }; /* * Increment the reference count of *packed_refs. */ static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs) { packed_refs->referrers++; } /* * Decrease the reference count of *packed_refs. If it goes to zero, * free *packed_refs and return true; otherwise return false. */ static int release_packed_ref_cache(struct packed_ref_cache *packed_refs) { if (!--packed_refs->referrers) { free_ref_cache(packed_refs->cache); stat_validity_clear(&packed_refs->validity); free(packed_refs); return 1; } else { return 0; } } static void clear_packed_ref_cache(struct files_ref_store *refs) { if (refs->packed) { struct packed_ref_cache *packed_refs = refs->packed; if (is_lock_file_locked(&refs->packed_refs_lock)) die("BUG: packed-ref cache cleared while locked"); refs->packed = NULL; release_packed_ref_cache(packed_refs); } } static void clear_loose_ref_cache(struct files_ref_store *refs) { if (refs->loose) { free_ref_cache(refs->loose); refs->loose = NULL; } } /* * Create a new submodule ref cache and add it to the internal * set of caches. */ static struct ref_store *files_ref_store_create(const char *gitdir, unsigned int flags) { struct files_ref_store *refs = xcalloc(1, sizeof(*refs)); struct ref_store *ref_store = (struct ref_store *)refs; struct strbuf sb = STRBUF_INIT; base_ref_store_init(ref_store, &refs_be_files); refs->store_flags = flags; refs->gitdir = xstrdup(gitdir); get_common_dir_noenv(&sb, gitdir); refs->gitcommondir = strbuf_detach(&sb, NULL); strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir); refs->packed_refs_path = strbuf_detach(&sb, NULL); return ref_store; } /* * Die if refs is not the main ref store. caller is used in any * necessary error messages. */ static void files_assert_main_repository(struct files_ref_store *refs, const char *caller) { if (refs->store_flags & REF_STORE_MAIN) return; die("BUG: operation %s only allowed for main ref store", caller); } /* * Downcast ref_store to files_ref_store. Die if ref_store is not a * files_ref_store. required_flags is compared with ref_store's * store_flags to ensure the ref_store has all required capabilities. * "caller" is used in any necessary error messages. */ static struct files_ref_store *files_downcast(struct ref_store *ref_store, unsigned int required_flags, const char *caller) { struct files_ref_store *refs; if (ref_store->be != &refs_be_files) die("BUG: ref_store is type \"%s\" not \"files\" in %s", ref_store->be->name, caller); refs = (struct files_ref_store *)ref_store; if ((refs->store_flags & required_flags) != required_flags) die("BUG: operation %s requires abilities 0x%x, but only have 0x%x", caller, required_flags, refs->store_flags); return refs; } /* The length of a peeled reference line in packed-refs, including EOL: */ #define PEELED_LINE_LENGTH 42 /* * The packed-refs header line that we write out. Perhaps other * traits will be added later. The trailing space is required. */ static const char PACKED_REFS_HEADER[] = "# pack-refs with: peeled fully-peeled \n"; /* * Parse one line from a packed-refs file. Write the SHA1 to sha1. * Return a pointer to the refname within the line (null-terminated), * or NULL if there was a problem. */ static const char *parse_ref_line(struct strbuf *line, struct object_id *oid) { const char *ref; if (parse_oid_hex(line->buf, oid, &ref) < 0) return NULL; if (!isspace(*ref++)) return NULL; if (isspace(*ref)) return NULL; if (line->buf[line->len - 1] != '\n') return NULL; line->buf[--line->len] = 0; return ref; } /* * Read f, which is a packed-refs file, into dir. * * A comment line of the form "# pack-refs with: " may contain zero or * more traits. We interpret the traits as follows: * * No traits: * * Probably no references are peeled. But if the file contains a * peeled value for a reference, we will use it. * * peeled: * * References under "refs/tags/", if they *can* be peeled, *are* * peeled in this file. References outside of "refs/tags/" are * probably not peeled even if they could have been, but if we find * a peeled value for such a reference we will use it. * * fully-peeled: * * All references in the file that can be peeled are peeled. * Inversely (and this is more important), any references in the * file for which no peeled value is recorded is not peelable. This * trait should typically be written alongside "peeled" for * compatibility with older clients, but we do not require it * (i.e., "peeled" is a no-op if "fully-peeled" is set). */ static void read_packed_refs(FILE *f, struct ref_dir *dir) { struct ref_entry *last = NULL; struct strbuf line = STRBUF_INIT; enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE; while (strbuf_getwholeline(&line, f, '\n') != EOF) { struct object_id oid; const char *refname; const char *traits; if (skip_prefix(line.buf, "# pack-refs with:", &traits)) { if (strstr(traits, " fully-peeled ")) peeled = PEELED_FULLY; else if (strstr(traits, " peeled ")) peeled = PEELED_TAGS; /* perhaps other traits later as well */ continue; } refname = parse_ref_line(&line, &oid); if (refname) { int flag = REF_ISPACKED; if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) { if (!refname_is_safe(refname)) die("packed refname is dangerous: %s", refname); oidclr(&oid); flag |= REF_BAD_NAME | REF_ISBROKEN; } last = create_ref_entry(refname, &oid, flag, 0); if (peeled == PEELED_FULLY || (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/"))) last->flag |= REF_KNOWS_PEELED; add_ref_entry(dir, last); continue; } if (last && line.buf[0] == '^' && line.len == PEELED_LINE_LENGTH && line.buf[PEELED_LINE_LENGTH - 1] == '\n' && !get_oid_hex(line.buf + 1, &oid)) { oidcpy(&last->u.value.peeled, &oid); /* * Regardless of what the file header said, * we definitely know the value of *this* * reference: */ last->flag |= REF_KNOWS_PEELED; } } strbuf_release(&line); } static const char *files_packed_refs_path(struct files_ref_store *refs) { return refs->packed_refs_path; } static void files_reflog_path(struct files_ref_store *refs, struct strbuf *sb, const char *refname) { if (!refname) { /* * FIXME: of course this is wrong in multi worktree * setting. To be fixed real soon. */ strbuf_addf(sb, "%s/logs", refs->gitcommondir); return; } switch (ref_type(refname)) { case REF_TYPE_PER_WORKTREE: case REF_TYPE_PSEUDOREF: strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname); break; case REF_TYPE_NORMAL: strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname); break; default: die("BUG: unknown ref type %d of ref %s", ref_type(refname), refname); } } static void files_ref_path(struct files_ref_store *refs, struct strbuf *sb, const char *refname) { switch (ref_type(refname)) { case REF_TYPE_PER_WORKTREE: case REF_TYPE_PSEUDOREF: strbuf_addf(sb, "%s/%s", refs->gitdir, refname); break; case REF_TYPE_NORMAL: strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname); break; default: die("BUG: unknown ref type %d of ref %s", ref_type(refname), refname); } } /* * Get the packed_ref_cache for the specified files_ref_store, * creating it if necessary. */ static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs) { const char *packed_refs_file = files_packed_refs_path(refs); if (refs->packed && !stat_validity_check(&refs->packed->validity, packed_refs_file)) clear_packed_ref_cache(refs); if (!refs->packed) { FILE *f; refs->packed = xcalloc(1, sizeof(*refs->packed)); acquire_packed_ref_cache(refs->packed); refs->packed->cache = create_ref_cache(&refs->base, NULL); refs->packed->cache->root->flag &= ~REF_INCOMPLETE; f = fopen(packed_refs_file, "r"); if (f) { stat_validity_update(&refs->packed->validity, fileno(f)); read_packed_refs(f, get_ref_dir(refs->packed->cache->root)); fclose(f); } } return refs->packed; } static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache) { return get_ref_dir(packed_ref_cache->cache->root); } static struct ref_dir *get_packed_refs(struct files_ref_store *refs) { return get_packed_ref_dir(get_packed_ref_cache(refs)); } /* * Add a reference to the in-memory packed reference cache. This may * only be called while the packed-refs file is locked (see * lock_packed_refs()). To actually write the packed-refs file, call * commit_packed_refs(). */ static void add_packed_ref(struct files_ref_store *refs, const char *refname, const struct object_id *oid) { struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs); if (!is_lock_file_locked(&refs->packed_refs_lock)) die("BUG: packed refs not locked"); add_ref_entry(get_packed_ref_dir(packed_ref_cache), create_ref_entry(refname, oid, REF_ISPACKED, 1)); } /* * Read the loose references from the namespace dirname into dir * (without recursing). dirname must end with '/'. dir must be the * directory entry corresponding to dirname. */ static void loose_fill_ref_dir(struct ref_store *ref_store, struct ref_dir *dir, const char *dirname) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_READ, "fill_ref_dir"); DIR *d; struct dirent *de; int dirnamelen = strlen(dirname); struct strbuf refname; struct strbuf path = STRBUF_INIT; size_t path_baselen; files_ref_path(refs, &path, dirname); path_baselen = path.len; d = opendir(path.buf); if (!d) { strbuf_release(&path); return; } strbuf_init(&refname, dirnamelen + 257); strbuf_add(&refname, dirname, dirnamelen); while ((de = readdir(d)) != NULL) { struct object_id oid; struct stat st; int flag; if (de->d_name[0] == '.') continue; if (ends_with(de->d_name, ".lock")) continue; strbuf_addstr(&refname, de->d_name); strbuf_addstr(&path, de->d_name); if (stat(path.buf, &st) < 0) { ; /* silently ignore */ } else if (S_ISDIR(st.st_mode)) { strbuf_addch(&refname, '/'); add_entry_to_dir(dir, create_dir_entry(dir->cache, refname.buf, refname.len, 1)); } else { if (!refs_resolve_ref_unsafe(&refs->base, refname.buf, RESOLVE_REF_READING, oid.hash, &flag)) { oidclr(&oid); flag |= REF_ISBROKEN; } else if (is_null_oid(&oid)) { /* * It is so astronomically unlikely * that NULL_SHA1 is the SHA-1 of an * actual object that we consider its * appearance in a loose reference * file to be repo corruption * (probably due to a software bug). */ flag |= REF_ISBROKEN; } if (check_refname_format(refname.buf, REFNAME_ALLOW_ONELEVEL)) { if (!refname_is_safe(refname.buf)) die("loose refname is dangerous: %s", refname.buf); oidclr(&oid); flag |= REF_BAD_NAME | REF_ISBROKEN; } add_entry_to_dir(dir, create_ref_entry(refname.buf, &oid, flag, 0)); } strbuf_setlen(&refname, dirnamelen); strbuf_setlen(&path, path_baselen); } strbuf_release(&refname); strbuf_release(&path); closedir(d); /* * Manually add refs/bisect, which, being per-worktree, might * not appear in the directory listing for refs/ in the main * repo. */ if (!strcmp(dirname, "refs/")) { int pos = search_ref_dir(dir, "refs/bisect/", 12); if (pos < 0) { struct ref_entry *child_entry = create_dir_entry( dir->cache, "refs/bisect/", 12, 1); add_entry_to_dir(dir, child_entry); } } } static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs) { if (!refs->loose) { /* * Mark the top-level directory complete because we * are about to read the only subdirectory that can * hold references: */ refs->loose = create_ref_cache(&refs->base, loose_fill_ref_dir); /* We're going to fill the top level ourselves: */ refs->loose->root->flag &= ~REF_INCOMPLETE; /* * Add an incomplete entry for "refs/" (to be filled * lazily): */ add_entry_to_dir(get_ref_dir(refs->loose->root), create_dir_entry(refs->loose, "refs/", 5, 1)); } return refs->loose; } /* * Return the ref_entry for the given refname from the packed * references. If it does not exist, return NULL. */ static struct ref_entry *get_packed_ref(struct files_ref_store *refs, const char *refname) { return find_ref_entry(get_packed_refs(refs), refname); } /* * A loose ref file doesn't exist; check for a packed ref. */ static int resolve_packed_ref(struct files_ref_store *refs, const char *refname, unsigned char *sha1, unsigned int *flags) { struct ref_entry *entry; /* * The loose reference file does not exist; check for a packed * reference. */ entry = get_packed_ref(refs, refname); if (entry) { hashcpy(sha1, entry->u.value.oid.hash); *flags |= REF_ISPACKED; return 0; } /* refname is not a packed reference. */ return -1; } static int files_read_raw_ref(struct ref_store *ref_store, const char *refname, unsigned char *sha1, struct strbuf *referent, unsigned int *type) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_READ, "read_raw_ref"); struct strbuf sb_contents = STRBUF_INIT; struct strbuf sb_path = STRBUF_INIT; const char *path; const char *buf; struct stat st; int fd; int ret = -1; int save_errno; int remaining_retries = 3; *type = 0; strbuf_reset(&sb_path); files_ref_path(refs, &sb_path, refname); path = sb_path.buf; stat_ref: /* * We might have to loop back here to avoid a race * condition: first we lstat() the file, then we try * to read it as a link or as a file. But if somebody * changes the type of the file (file <-> directory * <-> symlink) between the lstat() and reading, then * we don't want to report that as an error but rather * try again starting with the lstat(). * * We'll keep a count of the retries, though, just to avoid * any confusing situation sending us into an infinite loop. */ if (remaining_retries-- <= 0) goto out; if (lstat(path, &st) < 0) { if (errno != ENOENT) goto out; if (resolve_packed_ref(refs, refname, sha1, type)) { errno = ENOENT; goto out; } ret = 0; goto out; } /* Follow "normalized" - ie "refs/.." symlinks by hand */ if (S_ISLNK(st.st_mode)) { strbuf_reset(&sb_contents); if (strbuf_readlink(&sb_contents, path, 0) < 0) { if (errno == ENOENT || errno == EINVAL) /* inconsistent with lstat; retry */ goto stat_ref; else goto out; } if (starts_with(sb_contents.buf, "refs/") && !check_refname_format(sb_contents.buf, 0)) { strbuf_swap(&sb_contents, referent); *type |= REF_ISSYMREF; ret = 0; goto out; } /* * It doesn't look like a refname; fall through to just * treating it like a non-symlink, and reading whatever it * points to. */ } /* Is it a directory? */ if (S_ISDIR(st.st_mode)) { /* * Even though there is a directory where the loose * ref is supposed to be, there could still be a * packed ref: */ if (resolve_packed_ref(refs, refname, sha1, type)) { errno = EISDIR; goto out; } ret = 0; goto out; } /* * Anything else, just open it and try to use it as * a ref */ fd = open(path, O_RDONLY); if (fd < 0) { if (errno == ENOENT && !S_ISLNK(st.st_mode)) /* inconsistent with lstat; retry */ goto stat_ref; else goto out; } strbuf_reset(&sb_contents); if (strbuf_read(&sb_contents, fd, 256) < 0) { int save_errno = errno; close(fd); errno = save_errno; goto out; } close(fd); strbuf_rtrim(&sb_contents); buf = sb_contents.buf; if (starts_with(buf, "ref:")) { buf += 4; while (isspace(*buf)) buf++; strbuf_reset(referent); strbuf_addstr(referent, buf); *type |= REF_ISSYMREF; ret = 0; goto out; } /* * Please note that FETCH_HEAD has additional * data after the sha. */ if (get_sha1_hex(buf, sha1) || (buf[40] != '\0' && !isspace(buf[40]))) { *type |= REF_ISBROKEN; errno = EINVAL; goto out; } ret = 0; out: save_errno = errno; strbuf_release(&sb_path); strbuf_release(&sb_contents); errno = save_errno; return ret; } static void unlock_ref(struct ref_lock *lock) { /* Do not free lock->lk -- atexit() still looks at them */ if (lock->lk) rollback_lock_file(lock->lk); free(lock->ref_name); free(lock); } /* * Lock refname, without following symrefs, and set *lock_p to point * at a newly-allocated lock object. Fill in lock->old_oid, referent, * and type similarly to read_raw_ref(). * * The caller must verify that refname is a "safe" reference name (in * the sense of refname_is_safe()) before calling this function. * * If the reference doesn't already exist, verify that refname doesn't * have a D/F conflict with any existing references. extras and skip * are passed to refs_verify_refname_available() for this check. * * If mustexist is not set and the reference is not found or is * broken, lock the reference anyway but clear sha1. * * Return 0 on success. On failure, write an error message to err and * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR. * * Implementation note: This function is basically * * lock reference * read_raw_ref() * * but it includes a lot more code to * - Deal with possible races with other processes * - Avoid calling refs_verify_refname_available() when it can be * avoided, namely if we were successfully able to read the ref * - Generate informative error messages in the case of failure */ static int lock_raw_ref(struct files_ref_store *refs, const char *refname, int mustexist, const struct string_list *extras, const struct string_list *skip, struct ref_lock **lock_p, struct strbuf *referent, unsigned int *type, struct strbuf *err) { struct ref_lock *lock; struct strbuf ref_file = STRBUF_INIT; int attempts_remaining = 3; int ret = TRANSACTION_GENERIC_ERROR; assert(err); files_assert_main_repository(refs, "lock_raw_ref"); *type = 0; /* First lock the file so it can't change out from under us. */ *lock_p = lock = xcalloc(1, sizeof(*lock)); lock->ref_name = xstrdup(refname); files_ref_path(refs, &ref_file, refname); retry: switch (safe_create_leading_directories(ref_file.buf)) { case SCLD_OK: break; /* success */ case SCLD_EXISTS: /* * Suppose refname is "refs/foo/bar". We just failed * to create the containing directory, "refs/foo", * because there was a non-directory in the way. This * indicates a D/F conflict, probably because of * another reference such as "refs/foo". There is no * reason to expect this error to be transitory. */ if (refs_verify_refname_available(&refs->base, refname, extras, skip, err)) { if (mustexist) { /* * To the user the relevant error is * that the "mustexist" reference is * missing: */ strbuf_reset(err); strbuf_addf(err, "unable to resolve reference '%s'", refname); } else { /* * The error message set by * refs_verify_refname_available() is * OK. */ ret = TRANSACTION_NAME_CONFLICT; } } else { /* * The file that is in the way isn't a loose * reference. Report it as a low-level * failure. */ strbuf_addf(err, "unable to create lock file %s.lock; " "non-directory in the way", ref_file.buf); } goto error_return; case SCLD_VANISHED: /* Maybe another process was tidying up. Try again. */ if (--attempts_remaining > 0) goto retry; /* fall through */ default: strbuf_addf(err, "unable to create directory for %s", ref_file.buf); goto error_return; } if (!lock->lk) lock->lk = xcalloc(1, sizeof(struct lock_file)); if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) { if (errno == ENOENT && --attempts_remaining > 0) { /* * Maybe somebody just deleted one of the * directories leading to ref_file. Try * again: */ goto retry; } else { unable_to_lock_message(ref_file.buf, errno, err); goto error_return; } } /* * Now we hold the lock and can read the reference without * fear that its value will change. */ if (files_read_raw_ref(&refs->base, refname, lock->old_oid.hash, referent, type)) { if (errno == ENOENT) { if (mustexist) { /* Garden variety missing reference. */ strbuf_addf(err, "unable to resolve reference '%s'", refname); goto error_return; } else { /* * Reference is missing, but that's OK. We * know that there is not a conflict with * another loose reference because * (supposing that we are trying to lock * reference "refs/foo/bar"): * * - We were successfully able to create * the lockfile refs/foo/bar.lock, so we * know there cannot be a loose reference * named "refs/foo". * * - We got ENOENT and not EISDIR, so we * know that there cannot be a loose * reference named "refs/foo/bar/baz". */ } } else if (errno == EISDIR) { /* * There is a directory in the way. It might have * contained references that have been deleted. If * we don't require that the reference already * exists, try to remove the directory so that it * doesn't cause trouble when we want to rename the * lockfile into place later. */ if (mustexist) { /* Garden variety missing reference. */ strbuf_addf(err, "unable to resolve reference '%s'", refname); goto error_return; } else if (remove_dir_recursively(&ref_file, REMOVE_DIR_EMPTY_ONLY)) { if (refs_verify_refname_available( &refs->base, refname, extras, skip, err)) { /* * The error message set by * verify_refname_available() is OK. */ ret = TRANSACTION_NAME_CONFLICT; goto error_return; } else { /* * We can't delete the directory, * but we also don't know of any * references that it should * contain. */ strbuf_addf(err, "there is a non-empty directory '%s' " "blocking reference '%s'", ref_file.buf, refname); goto error_return; } } } else if (errno == EINVAL && (*type & REF_ISBROKEN)) { strbuf_addf(err, "unable to resolve reference '%s': " "reference broken", refname); goto error_return; } else { strbuf_addf(err, "unable to resolve reference '%s': %s", refname, strerror(errno)); goto error_return; } /* * If the ref did not exist and we are creating it, * make sure there is no existing ref that conflicts * with refname: */ if (refs_verify_refname_available( &refs->base, refname, extras, skip, err)) goto error_return; } ret = 0; goto out; error_return: unlock_ref(lock); *lock_p = NULL; out: strbuf_release(&ref_file); return ret; } static int files_peel_ref(struct ref_store *ref_store, const char *refname, unsigned char *sha1) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB, "peel_ref"); int flag; unsigned char base[20]; if (current_ref_iter && current_ref_iter->refname == refname) { struct object_id peeled; if (ref_iterator_peel(current_ref_iter, &peeled)) return -1; hashcpy(sha1, peeled.hash); return 0; } if (refs_read_ref_full(ref_store, refname, RESOLVE_REF_READING, base, &flag)) return -1; /* * If the reference is packed, read its ref_entry from the * cache in the hope that we already know its peeled value. * We only try this optimization on packed references because * (a) forcing the filling of the loose reference cache could * be expensive and (b) loose references anyway usually do not * have REF_KNOWS_PEELED. */ if (flag & REF_ISPACKED) { struct ref_entry *r = get_packed_ref(refs, refname); if (r) { if (peel_entry(r, 0)) return -1; hashcpy(sha1, r->u.value.peeled.hash); return 0; } } return peel_object(base, sha1); } struct files_ref_iterator { struct ref_iterator base; struct packed_ref_cache *packed_ref_cache; struct ref_iterator *iter0; unsigned int flags; }; static int files_ref_iterator_advance(struct ref_iterator *ref_iterator) { struct files_ref_iterator *iter = (struct files_ref_iterator *)ref_iterator; int ok; while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) { if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY && ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE) continue; if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) && !ref_resolves_to_object(iter->iter0->refname, iter->iter0->oid, iter->iter0->flags)) continue; iter->base.refname = iter->iter0->refname; iter->base.oid = iter->iter0->oid; iter->base.flags = iter->iter0->flags; return ITER_OK; } iter->iter0 = NULL; if (ref_iterator_abort(ref_iterator) != ITER_DONE) ok = ITER_ERROR; return ok; } static int files_ref_iterator_peel(struct ref_iterator *ref_iterator, struct object_id *peeled) { struct files_ref_iterator *iter = (struct files_ref_iterator *)ref_iterator; return ref_iterator_peel(iter->iter0, peeled); } static int files_ref_iterator_abort(struct ref_iterator *ref_iterator) { struct files_ref_iterator *iter = (struct files_ref_iterator *)ref_iterator; int ok = ITER_DONE; if (iter->iter0) ok = ref_iterator_abort(iter->iter0); release_packed_ref_cache(iter->packed_ref_cache); base_ref_iterator_free(ref_iterator); return ok; } static struct ref_iterator_vtable files_ref_iterator_vtable = { files_ref_iterator_advance, files_ref_iterator_peel, files_ref_iterator_abort }; static struct ref_iterator *files_ref_iterator_begin( struct ref_store *ref_store, const char *prefix, unsigned int flags) { struct files_ref_store *refs; struct ref_iterator *loose_iter, *packed_iter; struct files_ref_iterator *iter; struct ref_iterator *ref_iterator; if (ref_paranoia < 0) ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0); if (ref_paranoia) flags |= DO_FOR_EACH_INCLUDE_BROKEN; refs = files_downcast(ref_store, REF_STORE_READ | (ref_paranoia ? 0 : REF_STORE_ODB), "ref_iterator_begin"); iter = xcalloc(1, sizeof(*iter)); ref_iterator = &iter->base; base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable); /* * We must make sure that all loose refs are read before * accessing the packed-refs file; this avoids a race * condition if loose refs are migrated to the packed-refs * file by a simultaneous process, but our in-memory view is * from before the migration. We ensure this as follows: * First, we call start the loose refs iteration with its * `prime_ref` argument set to true. This causes the loose * references in the subtree to be pre-read into the cache. * (If they've already been read, that's OK; we only need to * guarantee that they're read before the packed refs, not * *how much* before.) After that, we call * get_packed_ref_cache(), which internally checks whether the * packed-ref cache is up to date with what is on disk, and * re-reads it if not. */ loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), prefix, 1); iter->packed_ref_cache = get_packed_ref_cache(refs); acquire_packed_ref_cache(iter->packed_ref_cache); packed_iter = cache_ref_iterator_begin(iter->packed_ref_cache->cache, prefix, 0); iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter); iter->flags = flags; return ref_iterator; } /* * Verify that the reference locked by lock has the value old_sha1. * Fail if the reference doesn't exist and mustexist is set. Return 0 * on success. On error, write an error message to err, set errno, and * return a negative value. */ static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock, const unsigned char *old_sha1, int mustexist, struct strbuf *err) { assert(err); if (refs_read_ref_full(ref_store, lock->ref_name, mustexist ? RESOLVE_REF_READING : 0, lock->old_oid.hash, NULL)) { if (old_sha1) { int save_errno = errno; strbuf_addf(err, "can't verify ref '%s'", lock->ref_name); errno = save_errno; return -1; } else { oidclr(&lock->old_oid); return 0; } } if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) { strbuf_addf(err, "ref '%s' is at %s but expected %s", lock->ref_name, oid_to_hex(&lock->old_oid), sha1_to_hex(old_sha1)); errno = EBUSY; return -1; } return 0; } static int remove_empty_directories(struct strbuf *path) { /* * we want to create a file but there is a directory there; * if that is an empty directory (or a directory that contains * only empty directories), remove them. */ return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY); } static int create_reflock(const char *path, void *cb) { struct lock_file *lk = cb; return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0; } /* * Locks a ref returning the lock on success and NULL on failure. * On failure errno is set to something meaningful. */ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs, const char *refname, const unsigned char *old_sha1, const struct string_list *extras, const struct string_list *skip, unsigned int flags, int *type, struct strbuf *err) { struct strbuf ref_file = STRBUF_INIT; struct ref_lock *lock; int last_errno = 0; int mustexist = (old_sha1 && !is_null_sha1(old_sha1)); int resolve_flags = RESOLVE_REF_NO_RECURSE; int resolved; files_assert_main_repository(refs, "lock_ref_sha1_basic"); assert(err); lock = xcalloc(1, sizeof(struct ref_lock)); if (mustexist) resolve_flags |= RESOLVE_REF_READING; if (flags & REF_DELETING) resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME; files_ref_path(refs, &ref_file, refname); resolved = !!refs_resolve_ref_unsafe(&refs->base, refname, resolve_flags, lock->old_oid.hash, type); if (!resolved && errno == EISDIR) { /* * we are trying to lock foo but we used to * have foo/bar which now does not exist; * it is normal for the empty directory 'foo' * to remain. */ if (remove_empty_directories(&ref_file)) { last_errno = errno; if (!refs_verify_refname_available( &refs->base, refname, extras, skip, err)) strbuf_addf(err, "there are still refs under '%s'", refname); goto error_return; } resolved = !!refs_resolve_ref_unsafe(&refs->base, refname, resolve_flags, lock->old_oid.hash, type); } if (!resolved) { last_errno = errno; if (last_errno != ENOTDIR || !refs_verify_refname_available(&refs->base, refname, extras, skip, err)) strbuf_addf(err, "unable to resolve reference '%s': %s", refname, strerror(last_errno)); goto error_return; } /* * If the ref did not exist and we are creating it, make sure * there is no existing packed ref whose name begins with our * refname, nor a packed ref whose name is a proper prefix of * our refname. */ if (is_null_oid(&lock->old_oid) && refs_verify_refname_available(&refs->base, refname, extras, skip, err)) { last_errno = ENOTDIR; goto error_return; } lock->lk = xcalloc(1, sizeof(struct lock_file)); lock->ref_name = xstrdup(refname); if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) { last_errno = errno; unable_to_lock_message(ref_file.buf, errno, err); goto error_return; } if (verify_lock(&refs->base, lock, old_sha1, mustexist, err)) { last_errno = errno; goto error_return; } goto out; error_return: unlock_ref(lock); lock = NULL; out: strbuf_release(&ref_file); errno = last_errno; return lock; } /* * Write an entry to the packed-refs file for the specified refname. * If peeled is non-NULL, write it as the entry's peeled value. */ static void write_packed_entry(FILE *fh, const char *refname, const unsigned char *sha1, const unsigned char *peeled) { fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname); if (peeled) fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled)); } /* * Lock the packed-refs file for writing. Flags is passed to * hold_lock_file_for_update(). Return 0 on success. On errors, set * errno appropriately and return a nonzero value. */ static int lock_packed_refs(struct files_ref_store *refs, int flags) { static int timeout_configured = 0; static int timeout_value = 1000; struct packed_ref_cache *packed_ref_cache; files_assert_main_repository(refs, "lock_packed_refs"); if (!timeout_configured) { git_config_get_int("core.packedrefstimeout", &timeout_value); timeout_configured = 1; } if (hold_lock_file_for_update_timeout( &refs->packed_refs_lock, files_packed_refs_path(refs), flags, timeout_value) < 0) return -1; /* * Get the current packed-refs while holding the lock. If the * packed-refs file has been modified since we last read it, * this will automatically invalidate the cache and re-read * the packed-refs file. */ packed_ref_cache = get_packed_ref_cache(refs); /* Increment the reference count to prevent it from being freed: */ acquire_packed_ref_cache(packed_ref_cache); return 0; } /* * Write the current version of the packed refs cache from memory to * disk. The packed-refs file must already be locked for writing (see * lock_packed_refs()). Return zero on success. On errors, set errno * and return a nonzero value */ static int commit_packed_refs(struct files_ref_store *refs) { struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs); int ok, error = 0; int save_errno = 0; FILE *out; struct ref_iterator *iter; files_assert_main_repository(refs, "commit_packed_refs"); if (!is_lock_file_locked(&refs->packed_refs_lock)) die("BUG: packed-refs not locked"); out = fdopen_lock_file(&refs->packed_refs_lock, "w"); if (!out) die_errno("unable to fdopen packed-refs descriptor"); fprintf_or_die(out, "%s", PACKED_REFS_HEADER); iter = cache_ref_iterator_begin(packed_ref_cache->cache, NULL, 0); while ((ok = ref_iterator_advance(iter)) == ITER_OK) { struct object_id peeled; int peel_error = ref_iterator_peel(iter, &peeled); write_packed_entry(out, iter->refname, iter->oid->hash, peel_error ? NULL : peeled.hash); } if (ok != ITER_DONE) die("error while iterating over references"); if (commit_lock_file(&refs->packed_refs_lock)) { save_errno = errno; error = -1; } release_packed_ref_cache(packed_ref_cache); errno = save_errno; return error; } /* * Rollback the lockfile for the packed-refs file, and discard the * in-memory packed reference cache. (The packed-refs file will be * read anew if it is needed again after this function is called.) */ static void rollback_packed_refs(struct files_ref_store *refs) { struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs); files_assert_main_repository(refs, "rollback_packed_refs"); if (!is_lock_file_locked(&refs->packed_refs_lock)) die("BUG: packed-refs not locked"); rollback_lock_file(&refs->packed_refs_lock); release_packed_ref_cache(packed_ref_cache); clear_packed_ref_cache(refs); } struct ref_to_prune { struct ref_to_prune *next; unsigned char sha1[20]; char name[FLEX_ARRAY]; }; enum { REMOVE_EMPTY_PARENTS_REF = 0x01, REMOVE_EMPTY_PARENTS_REFLOG = 0x02 }; /* * Remove empty parent directories associated with the specified * reference and/or its reflog, but spare [logs/]refs/ and immediate * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or * REMOVE_EMPTY_PARENTS_REFLOG. */ static void try_remove_empty_parents(struct files_ref_store *refs, const char *refname, unsigned int flags) { struct strbuf buf = STRBUF_INIT; struct strbuf sb = STRBUF_INIT; char *p, *q; int i; strbuf_addstr(&buf, refname); p = buf.buf; for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */ while (*p && *p != '/') p++; /* tolerate duplicate slashes; see check_refname_format() */ while (*p == '/') p++; } q = buf.buf + buf.len; while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) { while (q > p && *q != '/') q--; while (q > p && *(q-1) == '/') q--; if (q == p) break; strbuf_setlen(&buf, q - buf.buf); strbuf_reset(&sb); files_ref_path(refs, &sb, buf.buf); if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf)) flags &= ~REMOVE_EMPTY_PARENTS_REF; strbuf_reset(&sb); files_reflog_path(refs, &sb, buf.buf); if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf)) flags &= ~REMOVE_EMPTY_PARENTS_REFLOG; } strbuf_release(&buf); strbuf_release(&sb); } /* make sure nobody touched the ref, and unlink */ static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r) { struct ref_transaction *transaction; struct strbuf err = STRBUF_INIT; if (check_refname_format(r->name, 0)) return; transaction = ref_store_transaction_begin(&refs->base, &err); if (!transaction || ref_transaction_delete(transaction, r->name, r->sha1, REF_ISPRUNING | REF_NODEREF, NULL, &err) || ref_transaction_commit(transaction, &err)) { ref_transaction_free(transaction); error("%s", err.buf); strbuf_release(&err); return; } ref_transaction_free(transaction); strbuf_release(&err); } static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r) { while (r) { prune_ref(refs, r); r = r->next; } } static int files_pack_refs(struct ref_store *ref_store, unsigned int flags) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB, "pack_refs"); struct ref_iterator *iter; struct ref_dir *packed_refs; int ok; struct ref_to_prune *refs_to_prune = NULL; lock_packed_refs(refs, LOCK_DIE_ON_ERROR); packed_refs = get_packed_refs(refs); iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0); while ((ok = ref_iterator_advance(iter)) == ITER_OK) { /* * If the loose reference can be packed, add an entry * in the packed ref cache. If the reference should be * pruned, also add it to refs_to_prune. */ struct ref_entry *packed_entry; int is_tag_ref = starts_with(iter->refname, "refs/tags/"); /* Do not pack per-worktree refs: */ if (ref_type(iter->refname) != REF_TYPE_NORMAL) continue; /* ALWAYS pack tags */ if (!(flags & PACK_REFS_ALL) && !is_tag_ref) continue; /* Do not pack symbolic or broken refs: */ if (iter->flags & REF_ISSYMREF) continue; if (!ref_resolves_to_object(iter->refname, iter->oid, iter->flags)) continue; /* * Create an entry in the packed-refs cache equivalent * to the one from the loose ref cache, except that * we don't copy the peeled status, because we want it * to be re-peeled. */ packed_entry = find_ref_entry(packed_refs, iter->refname); if (packed_entry) { /* Overwrite existing packed entry with info from loose entry */ packed_entry->flag = REF_ISPACKED; oidcpy(&packed_entry->u.value.oid, iter->oid); } else { packed_entry = create_ref_entry(iter->refname, iter->oid, REF_ISPACKED, 0); add_ref_entry(packed_refs, packed_entry); } oidclr(&packed_entry->u.value.peeled); /* Schedule the loose reference for pruning if requested. */ if ((flags & PACK_REFS_PRUNE)) { struct ref_to_prune *n; FLEX_ALLOC_STR(n, name, iter->refname); hashcpy(n->sha1, iter->oid->hash); n->next = refs_to_prune; refs_to_prune = n; } } if (ok != ITER_DONE) die("error while iterating over references"); if (commit_packed_refs(refs)) die_errno("unable to overwrite old ref-pack file"); prune_refs(refs, refs_to_prune); return 0; } /* * Rewrite the packed-refs file, omitting any refs listed in * 'refnames'. On error, leave packed-refs unchanged, write an error * message to 'err', and return a nonzero value. * * The refs in 'refnames' needn't be sorted. `err` must not be NULL. */ static int repack_without_refs(struct files_ref_store *refs, struct string_list *refnames, struct strbuf *err) { struct ref_dir *packed; struct string_list_item *refname; int ret, needs_repacking = 0, removed = 0; files_assert_main_repository(refs, "repack_without_refs"); assert(err); /* Look for a packed ref */ for_each_string_list_item(refname, refnames) { if (get_packed_ref(refs, refname->string)) { needs_repacking = 1; break; } } /* Avoid locking if we have nothing to do */ if (!needs_repacking) return 0; /* no refname exists in packed refs */ if (lock_packed_refs(refs, 0)) { unable_to_lock_message(files_packed_refs_path(refs), errno, err); return -1; } packed = get_packed_refs(refs); /* Remove refnames from the cache */ for_each_string_list_item(refname, refnames) if (remove_entry_from_dir(packed, refname->string) != -1) removed = 1; if (!removed) { /* * All packed entries disappeared while we were * acquiring the lock. */ rollback_packed_refs(refs); return 0; } /* Write what remains */ ret = commit_packed_refs(refs); if (ret) strbuf_addf(err, "unable to overwrite old ref-pack file: %s", strerror(errno)); return ret; } static int files_delete_refs(struct ref_store *ref_store, const char *msg, struct string_list *refnames, unsigned int flags) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE, "delete_refs"); struct strbuf err = STRBUF_INIT; int i, result = 0; if (!refnames->nr) return 0; result = repack_without_refs(refs, refnames, &err); if (result) { /* * If we failed to rewrite the packed-refs file, then * it is unsafe to try to remove loose refs, because * doing so might expose an obsolete packed value for * a reference that might even point at an object that * has been garbage collected. */ if (refnames->nr == 1) error(_("could not delete reference %s: %s"), refnames->items[0].string, err.buf); else error(_("could not delete references: %s"), err.buf); goto out; } for (i = 0; i < refnames->nr; i++) { const char *refname = refnames->items[i].string; if (refs_delete_ref(&refs->base, msg, refname, NULL, flags)) result |= error(_("could not remove reference %s"), refname); } out: strbuf_release(&err); return result; } /* * People using contrib's git-new-workdir have .git/logs/refs -> * /some/other/path/.git/logs/refs, and that may live on another device. * * IOW, to avoid cross device rename errors, the temporary renamed log must * live into logs/refs. */ #define TMP_RENAMED_LOG "refs/.tmp-renamed-log" struct rename_cb { const char *tmp_renamed_log; int true_errno; }; static int rename_tmp_log_callback(const char *path, void *cb_data) { struct rename_cb *cb = cb_data; if (rename(cb->tmp_renamed_log, path)) { /* * rename(a, b) when b is an existing directory ought * to result in ISDIR, but Solaris 5.8 gives ENOTDIR. * Sheesh. Record the true errno for error reporting, * but report EISDIR to raceproof_create_file() so * that it knows to retry. */ cb->true_errno = errno; if (errno == ENOTDIR) errno = EISDIR; return -1; } else { return 0; } } static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname) { struct strbuf path = STRBUF_INIT; struct strbuf tmp = STRBUF_INIT; struct rename_cb cb; int ret; files_reflog_path(refs, &path, newrefname); files_reflog_path(refs, &tmp, TMP_RENAMED_LOG); cb.tmp_renamed_log = tmp.buf; ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb); if (ret) { if (errno == EISDIR) error("directory not empty: %s", path.buf); else error("unable to move logfile %s to %s: %s", tmp.buf, path.buf, strerror(cb.true_errno)); } strbuf_release(&path); strbuf_release(&tmp); return ret; } static int write_ref_to_lockfile(struct ref_lock *lock, const struct object_id *oid, struct strbuf *err); static int commit_ref_update(struct files_ref_store *refs, struct ref_lock *lock, const struct object_id *oid, const char *logmsg, struct strbuf *err); static int files_rename_ref(struct ref_store *ref_store, const char *oldrefname, const char *newrefname, const char *logmsg) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE, "rename_ref"); struct object_id oid, orig_oid; int flag = 0, logmoved = 0; struct ref_lock *lock; struct stat loginfo; struct strbuf sb_oldref = STRBUF_INIT; struct strbuf sb_newref = STRBUF_INIT; struct strbuf tmp_renamed_log = STRBUF_INIT; int log, ret; struct strbuf err = STRBUF_INIT; files_reflog_path(refs, &sb_oldref, oldrefname); files_reflog_path(refs, &sb_newref, newrefname); files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG); log = !lstat(sb_oldref.buf, &loginfo); if (log && S_ISLNK(loginfo.st_mode)) { ret = error("reflog for %s is a symlink", oldrefname); goto out; } if (!refs_resolve_ref_unsafe(&refs->base, oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE, orig_oid.hash, &flag)) { ret = error("refname %s not found", oldrefname); goto out; } if (flag & REF_ISSYMREF) { ret = error("refname %s is a symbolic ref, renaming it is not supported", oldrefname); goto out; } if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) { ret = 1; goto out; } if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) { ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s", oldrefname, strerror(errno)); goto out; } if (refs_delete_ref(&refs->base, logmsg, oldrefname, orig_oid.hash, REF_NODEREF)) { error("unable to delete old %s", oldrefname); goto rollback; } /* * Since we are doing a shallow lookup, oid is not the * correct value to pass to delete_ref as old_oid. But that * doesn't matter, because an old_oid check wouldn't add to * the safety anyway; we want to delete the reference whatever * its current value. */ if (!refs_read_ref_full(&refs->base, newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE, oid.hash, NULL) && refs_delete_ref(&refs->base, NULL, newrefname, NULL, REF_NODEREF)) { if (errno == EISDIR) { struct strbuf path = STRBUF_INIT; int result; files_ref_path(refs, &path, newrefname); result = remove_empty_directories(&path); strbuf_release(&path); if (result) { error("Directory not empty: %s", newrefname); goto rollback; } } else { error("unable to delete existing %s", newrefname); goto rollback; } } if (log && rename_tmp_log(refs, newrefname)) goto rollback; logmoved = log; lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL, REF_NODEREF, NULL, &err); if (!lock) { error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf); strbuf_release(&err); goto rollback; } oidcpy(&lock->old_oid, &orig_oid); if (write_ref_to_lockfile(lock, &orig_oid, &err) || commit_ref_update(refs, lock, &orig_oid, logmsg, &err)) { error("unable to write current sha1 into %s: %s", newrefname, err.buf); strbuf_release(&err); goto rollback; } ret = 0; goto out; rollback: lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL, REF_NODEREF, NULL, &err); if (!lock) { error("unable to lock %s for rollback: %s", oldrefname, err.buf); strbuf_release(&err); goto rollbacklog; } flag = log_all_ref_updates; log_all_ref_updates = LOG_REFS_NONE; if (write_ref_to_lockfile(lock, &orig_oid, &err) || commit_ref_update(refs, lock, &orig_oid, NULL, &err)) { error("unable to write current sha1 into %s: %s", oldrefname, err.buf); strbuf_release(&err); } log_all_ref_updates = flag; rollbacklog: if (logmoved && rename(sb_newref.buf, sb_oldref.buf)) error("unable to restore logfile %s from %s: %s", oldrefname, newrefname, strerror(errno)); if (!logmoved && log && rename(tmp_renamed_log.buf, sb_oldref.buf)) error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s", oldrefname, strerror(errno)); ret = 1; out: strbuf_release(&sb_newref); strbuf_release(&sb_oldref); strbuf_release(&tmp_renamed_log); return ret; } static int close_ref(struct ref_lock *lock) { if (close_lock_file(lock->lk)) return -1; return 0; } static int commit_ref(struct ref_lock *lock) { char *path = get_locked_file_path(lock->lk); struct stat st; if (!lstat(path, &st) && S_ISDIR(st.st_mode)) { /* * There is a directory at the path we want to rename * the lockfile to. Hopefully it is empty; try to * delete it. */ size_t len = strlen(path); struct strbuf sb_path = STRBUF_INIT; strbuf_attach(&sb_path, path, len, len); /* * If this fails, commit_lock_file() will also fail * and will report the problem. */ remove_empty_directories(&sb_path); strbuf_release(&sb_path); } else { free(path); } if (commit_lock_file(lock->lk)) return -1; return 0; } static int open_or_create_logfile(const char *path, void *cb) { int *fd = cb; *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666); return (*fd < 0) ? -1 : 0; } /* * Create a reflog for a ref. If force_create = 0, only create the * reflog for certain refs (those for which should_autocreate_reflog * returns non-zero). Otherwise, create it regardless of the reference * name. If the logfile already existed or was created, return 0 and * set *logfd to the file descriptor opened for appending to the file. * If no logfile exists and we decided not to create one, return 0 and * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and * return -1. */ static int log_ref_setup(struct files_ref_store *refs, const char *refname, int force_create, int *logfd, struct strbuf *err) { struct strbuf logfile_sb = STRBUF_INIT; char *logfile; files_reflog_path(refs, &logfile_sb, refname); logfile = strbuf_detach(&logfile_sb, NULL); if (force_create || should_autocreate_reflog(refname)) { if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) { if (errno == ENOENT) strbuf_addf(err, "unable to create directory for '%s': " "%s", logfile, strerror(errno)); else if (errno == EISDIR) strbuf_addf(err, "there are still logs under '%s'", logfile); else strbuf_addf(err, "unable to append to '%s': %s", logfile, strerror(errno)); goto error; } } else { *logfd = open(logfile, O_APPEND | O_WRONLY, 0666); if (*logfd < 0) { if (errno == ENOENT || errno == EISDIR) { /* * The logfile doesn't already exist, * but that is not an error; it only * means that we won't write log * entries to it. */ ; } else { strbuf_addf(err, "unable to append to '%s': %s", logfile, strerror(errno)); goto error; } } } if (*logfd >= 0) adjust_shared_perm(logfile); free(logfile); return 0; error: free(logfile); return -1; } static int files_create_reflog(struct ref_store *ref_store, const char *refname, int force_create, struct strbuf *err) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE, "create_reflog"); int fd; if (log_ref_setup(refs, refname, force_create, &fd, err)) return -1; if (fd >= 0) close(fd); return 0; } static int log_ref_write_fd(int fd, const struct object_id *old_oid, const struct object_id *new_oid, const char *committer, const char *msg) { int msglen, written; unsigned maxlen, len; char *logrec; msglen = msg ? strlen(msg) : 0; maxlen = strlen(committer) + msglen + 100; logrec = xmalloc(maxlen); len = xsnprintf(logrec, maxlen, "%s %s %s\n", oid_to_hex(old_oid), oid_to_hex(new_oid), committer); if (msglen) len += copy_reflog_msg(logrec + len - 1, msg) - 1; written = len <= maxlen ? write_in_full(fd, logrec, len) : -1; free(logrec); if (written != len) return -1; return 0; } static int files_log_ref_write(struct files_ref_store *refs, const char *refname, const struct object_id *old_oid, const struct object_id *new_oid, const char *msg, int flags, struct strbuf *err) { int logfd, result; if (log_all_ref_updates == LOG_REFS_UNSET) log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL; result = log_ref_setup(refs, refname, flags & REF_FORCE_CREATE_REFLOG, &logfd, err); if (result) return result; if (logfd < 0) return 0; result = log_ref_write_fd(logfd, old_oid, new_oid, git_committer_info(0), msg); if (result) { struct strbuf sb = STRBUF_INIT; int save_errno = errno; files_reflog_path(refs, &sb, refname); strbuf_addf(err, "unable to append to '%s': %s", sb.buf, strerror(save_errno)); strbuf_release(&sb); close(logfd); return -1; } if (close(logfd)) { struct strbuf sb = STRBUF_INIT; int save_errno = errno; files_reflog_path(refs, &sb, refname); strbuf_addf(err, "unable to append to '%s': %s", sb.buf, strerror(save_errno)); strbuf_release(&sb); return -1; } return 0; } /* * Write sha1 into the open lockfile, then close the lockfile. On * errors, rollback the lockfile, fill in *err and * return -1. */ static int write_ref_to_lockfile(struct ref_lock *lock, const struct object_id *oid, struct strbuf *err) { static char term = '\n'; struct object *o; int fd; o = parse_object(oid); if (!o) { strbuf_addf(err, "trying to write ref '%s' with nonexistent object %s", lock->ref_name, oid_to_hex(oid)); unlock_ref(lock); return -1; } if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) { strbuf_addf(err, "trying to write non-commit object %s to branch '%s'", oid_to_hex(oid), lock->ref_name); unlock_ref(lock); return -1; } fd = get_lock_file_fd(lock->lk); if (write_in_full(fd, oid_to_hex(oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ || write_in_full(fd, &term, 1) != 1 || close_ref(lock) < 0) { strbuf_addf(err, "couldn't write '%s'", get_lock_file_path(lock->lk)); unlock_ref(lock); return -1; } return 0; } /* * Commit a change to a loose reference that has already been written * to the loose reference lockfile. Also update the reflogs if * necessary, using the specified lockmsg (which can be NULL). */ static int commit_ref_update(struct files_ref_store *refs, struct ref_lock *lock, const struct object_id *oid, const char *logmsg, struct strbuf *err) { files_assert_main_repository(refs, "commit_ref_update"); clear_loose_ref_cache(refs); if (files_log_ref_write(refs, lock->ref_name, &lock->old_oid, oid, logmsg, 0, err)) { char *old_msg = strbuf_detach(err, NULL); strbuf_addf(err, "cannot update the ref '%s': %s", lock->ref_name, old_msg); free(old_msg); unlock_ref(lock); return -1; } if (strcmp(lock->ref_name, "HEAD") != 0) { /* * Special hack: If a branch is updated directly and HEAD * points to it (may happen on the remote side of a push * for example) then logically the HEAD reflog should be * updated too. * A generic solution implies reverse symref information, * but finding all symrefs pointing to the given branch * would be rather costly for this rare event (the direct * update of a branch) to be worth it. So let's cheat and * check with HEAD only which should cover 99% of all usage * scenarios (even 100% of the default ones). */ struct object_id head_oid; int head_flag; const char *head_ref; head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD", RESOLVE_REF_READING, head_oid.hash, &head_flag); if (head_ref && (head_flag & REF_ISSYMREF) && !strcmp(head_ref, lock->ref_name)) { struct strbuf log_err = STRBUF_INIT; if (files_log_ref_write(refs, "HEAD", &lock->old_oid, oid, logmsg, 0, &log_err)) { error("%s", log_err.buf); strbuf_release(&log_err); } } } if (commit_ref(lock)) { strbuf_addf(err, "couldn't set '%s'", lock->ref_name); unlock_ref(lock); return -1; } unlock_ref(lock); return 0; } static int create_ref_symlink(struct ref_lock *lock, const char *target) { int ret = -1; #ifndef NO_SYMLINK_HEAD char *ref_path = get_locked_file_path(lock->lk); unlink(ref_path); ret = symlink(target, ref_path); free(ref_path); if (ret) fprintf(stderr, "no symlink - falling back to symbolic ref\n"); #endif return ret; } static void update_symref_reflog(struct files_ref_store *refs, struct ref_lock *lock, const char *refname, const char *target, const char *logmsg) { struct strbuf err = STRBUF_INIT; struct object_id new_oid; if (logmsg && !refs_read_ref_full(&refs->base, target, RESOLVE_REF_READING, new_oid.hash, NULL) && files_log_ref_write(refs, refname, &lock->old_oid, &new_oid, logmsg, 0, &err)) { error("%s", err.buf); strbuf_release(&err); } } static int create_symref_locked(struct files_ref_store *refs, struct ref_lock *lock, const char *refname, const char *target, const char *logmsg) { if (prefer_symlink_refs && !create_ref_symlink(lock, target)) { update_symref_reflog(refs, lock, refname, target, logmsg); return 0; } if (!fdopen_lock_file(lock->lk, "w")) return error("unable to fdopen %s: %s", lock->lk->tempfile.filename.buf, strerror(errno)); update_symref_reflog(refs, lock, refname, target, logmsg); /* no error check; commit_ref will check ferror */ fprintf(lock->lk->tempfile.fp, "ref: %s\n", target); if (commit_ref(lock) < 0) return error("unable to write symref for %s: %s", refname, strerror(errno)); return 0; } static int files_create_symref(struct ref_store *ref_store, const char *refname, const char *target, const char *logmsg) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE, "create_symref"); struct strbuf err = STRBUF_INIT; struct ref_lock *lock; int ret; lock = lock_ref_sha1_basic(refs, refname, NULL, NULL, NULL, REF_NODEREF, NULL, &err); if (!lock) { error("%s", err.buf); strbuf_release(&err); return -1; } ret = create_symref_locked(refs, lock, refname, target, logmsg); unlock_ref(lock); return ret; } static int files_reflog_exists(struct ref_store *ref_store, const char *refname) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_READ, "reflog_exists"); struct strbuf sb = STRBUF_INIT; struct stat st; int ret; files_reflog_path(refs, &sb, refname); ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode); strbuf_release(&sb); return ret; } static int files_delete_reflog(struct ref_store *ref_store, const char *refname) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog"); struct strbuf sb = STRBUF_INIT; int ret; files_reflog_path(refs, &sb, refname); ret = remove_path(sb.buf); strbuf_release(&sb); return ret; } static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data) { struct object_id ooid, noid; char *email_end, *message; timestamp_t timestamp; int tz; const char *p = sb->buf; /* old SP new SP name SP time TAB msg LF */ if (!sb->len || sb->buf[sb->len - 1] != '\n' || parse_oid_hex(p, &ooid, &p) || *p++ != ' ' || parse_oid_hex(p, &noid, &p) || *p++ != ' ' || !(email_end = strchr(p, '>')) || email_end[1] != ' ' || !(timestamp = parse_timestamp(email_end + 2, &message, 10)) || !message || message[0] != ' ' || (message[1] != '+' && message[1] != '-') || !isdigit(message[2]) || !isdigit(message[3]) || !isdigit(message[4]) || !isdigit(message[5])) return 0; /* corrupt? */ email_end[1] = '\0'; tz = strtol(message + 1, NULL, 10); if (message[6] != '\t') message += 6; else message += 7; return fn(&ooid, &noid, p, timestamp, tz, message, cb_data); } static char *find_beginning_of_line(char *bob, char *scan) { while (bob < scan && *(--scan) != '\n') ; /* keep scanning backwards */ /* * Return either beginning of the buffer, or LF at the end of * the previous line. */ return scan; } static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store, const char *refname, each_reflog_ent_fn fn, void *cb_data) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_READ, "for_each_reflog_ent_reverse"); struct strbuf sb = STRBUF_INIT; FILE *logfp; long pos; int ret = 0, at_tail = 1; files_reflog_path(refs, &sb, refname); logfp = fopen(sb.buf, "r"); strbuf_release(&sb); if (!logfp) return -1; /* Jump to the end */ if (fseek(logfp, 0, SEEK_END) < 0) ret = error("cannot seek back reflog for %s: %s", refname, strerror(errno)); pos = ftell(logfp); while (!ret && 0 < pos) { int cnt; size_t nread; char buf[BUFSIZ]; char *endp, *scanp; /* Fill next block from the end */ cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos; if (fseek(logfp, pos - cnt, SEEK_SET)) { ret = error("cannot seek back reflog for %s: %s", refname, strerror(errno)); break; } nread = fread(buf, cnt, 1, logfp); if (nread != 1) { ret = error("cannot read %d bytes from reflog for %s: %s", cnt, refname, strerror(errno)); break; } pos -= cnt; scanp = endp = buf + cnt; if (at_tail && scanp[-1] == '\n') /* Looking at the final LF at the end of the file */ scanp--; at_tail = 0; while (buf < scanp) { /* * terminating LF of the previous line, or the beginning * of the buffer. */ char *bp; bp = find_beginning_of_line(buf, scanp); if (*bp == '\n') { /* * The newline is the end of the previous line, * so we know we have complete line starting * at (bp + 1). Prefix it onto any prior data * we collected for the line and process it. */ strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1)); scanp = bp; endp = bp + 1; ret = show_one_reflog_ent(&sb, fn, cb_data); strbuf_reset(&sb); if (ret) break; } else if (!pos) { /* * We are at the start of the buffer, and the * start of the file; there is no previous * line, and we have everything for this one. * Process it, and we can end the loop. */ strbuf_splice(&sb, 0, 0, buf, endp - buf); ret = show_one_reflog_ent(&sb, fn, cb_data); strbuf_reset(&sb); break; } if (bp == buf) { /* * We are at the start of the buffer, and there * is more file to read backwards. Which means * we are in the middle of a line. Note that we * may get here even if *bp was a newline; that * just means we are at the exact end of the * previous line, rather than some spot in the * middle. * * Save away what we have to be combined with * the data from the next read. */ strbuf_splice(&sb, 0, 0, buf, endp - buf); break; } } } if (!ret && sb.len) die("BUG: reverse reflog parser had leftover data"); fclose(logfp); strbuf_release(&sb); return ret; } static int files_for_each_reflog_ent(struct ref_store *ref_store, const char *refname, each_reflog_ent_fn fn, void *cb_data) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_READ, "for_each_reflog_ent"); FILE *logfp; struct strbuf sb = STRBUF_INIT; int ret = 0; files_reflog_path(refs, &sb, refname); logfp = fopen(sb.buf, "r"); strbuf_release(&sb); if (!logfp) return -1; while (!ret && !strbuf_getwholeline(&sb, logfp, '\n')) ret = show_one_reflog_ent(&sb, fn, cb_data); fclose(logfp); strbuf_release(&sb); return ret; } struct files_reflog_iterator { struct ref_iterator base; struct ref_store *ref_store; struct dir_iterator *dir_iterator; struct object_id oid; }; static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator) { struct files_reflog_iterator *iter = (struct files_reflog_iterator *)ref_iterator; struct dir_iterator *diter = iter->dir_iterator; int ok; while ((ok = dir_iterator_advance(diter)) == ITER_OK) { int flags; if (!S_ISREG(diter->st.st_mode)) continue; if (diter->basename[0] == '.') continue; if (ends_with(diter->basename, ".lock")) continue; if (refs_read_ref_full(iter->ref_store, diter->relative_path, 0, iter->oid.hash, &flags)) { error("bad ref for %s", diter->path.buf); continue; } iter->base.refname = diter->relative_path; iter->base.oid = &iter->oid; iter->base.flags = flags; return ITER_OK; } iter->dir_iterator = NULL; if (ref_iterator_abort(ref_iterator) == ITER_ERROR) ok = ITER_ERROR; return ok; } static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator, struct object_id *peeled) { die("BUG: ref_iterator_peel() called for reflog_iterator"); } static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator) { struct files_reflog_iterator *iter = (struct files_reflog_iterator *)ref_iterator; int ok = ITER_DONE; if (iter->dir_iterator) ok = dir_iterator_abort(iter->dir_iterator); base_ref_iterator_free(ref_iterator); return ok; } static struct ref_iterator_vtable files_reflog_iterator_vtable = { files_reflog_iterator_advance, files_reflog_iterator_peel, files_reflog_iterator_abort }; static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_READ, "reflog_iterator_begin"); struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter)); struct ref_iterator *ref_iterator = &iter->base; struct strbuf sb = STRBUF_INIT; base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable); files_reflog_path(refs, &sb, NULL); iter->dir_iterator = dir_iterator_begin(sb.buf); iter->ref_store = ref_store; strbuf_release(&sb); return ref_iterator; } static int ref_update_reject_duplicates(struct string_list *refnames, struct strbuf *err) { int i, n = refnames->nr; assert(err); for (i = 1; i < n; i++) if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) { strbuf_addf(err, "multiple updates for ref '%s' not allowed.", refnames->items[i].string); return 1; } return 0; } /* * If update is a direct update of head_ref (the reference pointed to * by HEAD), then add an extra REF_LOG_ONLY update for HEAD. */ static int split_head_update(struct ref_update *update, struct ref_transaction *transaction, const char *head_ref, struct string_list *affected_refnames, struct strbuf *err) { struct string_list_item *item; struct ref_update *new_update; if ((update->flags & REF_LOG_ONLY) || (update->flags & REF_ISPRUNING) || (update->flags & REF_UPDATE_VIA_HEAD)) return 0; if (strcmp(update->refname, head_ref)) return 0; /* * First make sure that HEAD is not already in the * transaction. This insertion is O(N) in the transaction * size, but it happens at most once per transaction. */ item = string_list_insert(affected_refnames, "HEAD"); if (item->util) { /* An entry already existed */ strbuf_addf(err, "multiple updates for 'HEAD' (including one " "via its referent '%s') are not allowed", update->refname); return TRANSACTION_NAME_CONFLICT; } new_update = ref_transaction_add_update( transaction, "HEAD", update->flags | REF_LOG_ONLY | REF_NODEREF, update->new_oid.hash, update->old_oid.hash, update->msg); item->util = new_update; return 0; } /* * update is for a symref that points at referent and doesn't have * REF_NODEREF set. Split it into two updates: * - The original update, but with REF_LOG_ONLY and REF_NODEREF set * - A new, separate update for the referent reference * Note that the new update will itself be subject to splitting when * the iteration gets to it. */ static int split_symref_update(struct files_ref_store *refs, struct ref_update *update, const char *referent, struct ref_transaction *transaction, struct string_list *affected_refnames, struct strbuf *err) { struct string_list_item *item; struct ref_update *new_update; unsigned int new_flags; /* * First make sure that referent is not already in the * transaction. This insertion is O(N) in the transaction * size, but it happens at most once per symref in a * transaction. */ item = string_list_insert(affected_refnames, referent); if (item->util) { /* An entry already existed */ strbuf_addf(err, "multiple updates for '%s' (including one " "via symref '%s') are not allowed", referent, update->refname); return TRANSACTION_NAME_CONFLICT; } new_flags = update->flags; if (!strcmp(update->refname, "HEAD")) { /* * Record that the new update came via HEAD, so that * when we process it, split_head_update() doesn't try * to add another reflog update for HEAD. Note that * this bit will be propagated if the new_update * itself needs to be split. */ new_flags |= REF_UPDATE_VIA_HEAD; } new_update = ref_transaction_add_update( transaction, referent, new_flags, update->new_oid.hash, update->old_oid.hash, update->msg); new_update->parent_update = update; /* * Change the symbolic ref update to log only. Also, it * doesn't need to check its old SHA-1 value, as that will be * done when new_update is processed. */ update->flags |= REF_LOG_ONLY | REF_NODEREF; update->flags &= ~REF_HAVE_OLD; item->util = new_update; return 0; } /* * Return the refname under which update was originally requested. */ static const char *original_update_refname(struct ref_update *update) { while (update->parent_update) update = update->parent_update; return update->refname; } /* * Check whether the REF_HAVE_OLD and old_oid values stored in update * are consistent with oid, which is the reference's current value. If * everything is OK, return 0; otherwise, write an error message to * err and return -1. */ static int check_old_oid(struct ref_update *update, struct object_id *oid, struct strbuf *err) { if (!(update->flags & REF_HAVE_OLD) || !oidcmp(oid, &update->old_oid)) return 0; if (is_null_oid(&update->old_oid)) strbuf_addf(err, "cannot lock ref '%s': " "reference already exists", original_update_refname(update)); else if (is_null_oid(oid)) strbuf_addf(err, "cannot lock ref '%s': " "reference is missing but expected %s", original_update_refname(update), oid_to_hex(&update->old_oid)); else strbuf_addf(err, "cannot lock ref '%s': " "is at %s but expected %s", original_update_refname(update), oid_to_hex(oid), oid_to_hex(&update->old_oid)); return -1; } /* * Prepare for carrying out update: * - Lock the reference referred to by update. * - Read the reference under lock. * - Check that its old SHA-1 value (if specified) is correct, and in * any case record it in update->lock->old_oid for later use when * writing the reflog. * - If it is a symref update without REF_NODEREF, split it up into a * REF_LOG_ONLY update of the symref and add a separate update for * the referent to transaction. * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY * update of HEAD. */ static int lock_ref_for_update(struct files_ref_store *refs, struct ref_update *update, struct ref_transaction *transaction, const char *head_ref, struct string_list *affected_refnames, struct strbuf *err) { struct strbuf referent = STRBUF_INIT; int mustexist = (update->flags & REF_HAVE_OLD) && !is_null_oid(&update->old_oid); int ret; struct ref_lock *lock; files_assert_main_repository(refs, "lock_ref_for_update"); if ((update->flags & REF_HAVE_NEW) && is_null_oid(&update->new_oid)) update->flags |= REF_DELETING; if (head_ref) { ret = split_head_update(update, transaction, head_ref, affected_refnames, err); if (ret) return ret; } ret = lock_raw_ref(refs, update->refname, mustexist, affected_refnames, NULL, &lock, &referent, &update->type, err); if (ret) { char *reason; reason = strbuf_detach(err, NULL); strbuf_addf(err, "cannot lock ref '%s': %s", original_update_refname(update), reason); free(reason); return ret; } update->backend_data = lock; if (update->type & REF_ISSYMREF) { if (update->flags & REF_NODEREF) { /* * We won't be reading the referent as part of * the transaction, so we have to read it here * to record and possibly check old_sha1: */ if (refs_read_ref_full(&refs->base, referent.buf, 0, lock->old_oid.hash, NULL)) { if (update->flags & REF_HAVE_OLD) { strbuf_addf(err, "cannot lock ref '%s': " "error reading reference", original_update_refname(update)); return -1; } } else if (check_old_oid(update, &lock->old_oid, err)) { return TRANSACTION_GENERIC_ERROR; } } else { /* * Create a new update for the reference this * symref is pointing at. Also, we will record * and verify old_sha1 for this update as part * of processing the split-off update, so we * don't have to do it here. */ ret = split_symref_update(refs, update, referent.buf, transaction, affected_refnames, err); if (ret) return ret; } } else { struct ref_update *parent_update; if (check_old_oid(update, &lock->old_oid, err)) return TRANSACTION_GENERIC_ERROR; /* * If this update is happening indirectly because of a * symref update, record the old SHA-1 in the parent * update: */ for (parent_update = update->parent_update; parent_update; parent_update = parent_update->parent_update) { struct ref_lock *parent_lock = parent_update->backend_data; oidcpy(&parent_lock->old_oid, &lock->old_oid); } } if ((update->flags & REF_HAVE_NEW) && !(update->flags & REF_DELETING) && !(update->flags & REF_LOG_ONLY)) { if (!(update->type & REF_ISSYMREF) && !oidcmp(&lock->old_oid, &update->new_oid)) { /* * The reference already has the desired * value, so we don't need to write it. */ } else if (write_ref_to_lockfile(lock, &update->new_oid, err)) { char *write_err = strbuf_detach(err, NULL); /* * The lock was freed upon failure of * write_ref_to_lockfile(): */ update->backend_data = NULL; strbuf_addf(err, "cannot update ref '%s': %s", update->refname, write_err); free(write_err); return TRANSACTION_GENERIC_ERROR; } else { update->flags |= REF_NEEDS_COMMIT; } } if (!(update->flags & REF_NEEDS_COMMIT)) { /* * We didn't call write_ref_to_lockfile(), so * the lockfile is still open. Close it to * free up the file descriptor: */ if (close_ref(lock)) { strbuf_addf(err, "couldn't close '%s.lock'", update->refname); return TRANSACTION_GENERIC_ERROR; } } return 0; } /* * Unlock any references in `transaction` that are still locked, and * mark the transaction closed. */ static void files_transaction_cleanup(struct ref_transaction *transaction) { size_t i; for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; struct ref_lock *lock = update->backend_data; if (lock) { unlock_ref(lock); update->backend_data = NULL; } } transaction->state = REF_TRANSACTION_CLOSED; } static int files_transaction_commit(struct ref_store *ref_store, struct ref_transaction *transaction, struct strbuf *err) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE, "ref_transaction_commit"); size_t i; int ret = 0; struct string_list refs_to_delete = STRING_LIST_INIT_NODUP; struct string_list_item *ref_to_delete; struct string_list affected_refnames = STRING_LIST_INIT_NODUP; char *head_ref = NULL; int head_type; struct object_id head_oid; struct strbuf sb = STRBUF_INIT; assert(err); if (!transaction->nr) goto cleanup; /* * Fail if a refname appears more than once in the * transaction. (If we end up splitting up any updates using * split_symref_update() or split_head_update(), those * functions will check that the new updates don't have the * same refname as any existing ones.) */ for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; struct string_list_item *item = string_list_append(&affected_refnames, update->refname); /* * We store a pointer to update in item->util, but at * the moment we never use the value of this field * except to check whether it is non-NULL. */ item->util = update; } string_list_sort(&affected_refnames); if (ref_update_reject_duplicates(&affected_refnames, err)) { ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } /* * Special hack: If a branch is updated directly and HEAD * points to it (may happen on the remote side of a push * for example) then logically the HEAD reflog should be * updated too. * * A generic solution would require reverse symref lookups, * but finding all symrefs pointing to a given branch would be * rather costly for this rare event (the direct update of a * branch) to be worth it. So let's cheat and check with HEAD * only, which should cover 99% of all usage scenarios (even * 100% of the default ones). * * So if HEAD is a symbolic reference, then record the name of * the reference that it points to. If we see an update of * head_ref within the transaction, then split_head_update() * arranges for the reflog of HEAD to be updated, too. */ head_ref = refs_resolve_refdup(ref_store, "HEAD", RESOLVE_REF_NO_RECURSE, head_oid.hash, &head_type); if (head_ref && !(head_type & REF_ISSYMREF)) { free(head_ref); head_ref = NULL; } /* * Acquire all locks, verify old values if provided, check * that new values are valid, and write new values to the * lockfiles, ready to be activated. Only keep one lockfile * open at a time to avoid running out of file descriptors. */ for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; ret = lock_ref_for_update(refs, update, transaction, head_ref, &affected_refnames, err); if (ret) goto cleanup; } /* Perform updates first so live commits remain referenced */ for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; struct ref_lock *lock = update->backend_data; if (update->flags & REF_NEEDS_COMMIT || update->flags & REF_LOG_ONLY) { if (files_log_ref_write(refs, lock->ref_name, &lock->old_oid, &update->new_oid, update->msg, update->flags, err)) { char *old_msg = strbuf_detach(err, NULL); strbuf_addf(err, "cannot update the ref '%s': %s", lock->ref_name, old_msg); free(old_msg); unlock_ref(lock); update->backend_data = NULL; ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } } if (update->flags & REF_NEEDS_COMMIT) { clear_loose_ref_cache(refs); if (commit_ref(lock)) { strbuf_addf(err, "couldn't set '%s'", lock->ref_name); unlock_ref(lock); update->backend_data = NULL; ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } } } /* Perform deletes now that updates are safely completed */ for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; struct ref_lock *lock = update->backend_data; if (update->flags & REF_DELETING && !(update->flags & REF_LOG_ONLY)) { if (!(update->type & REF_ISPACKED) || update->type & REF_ISSYMREF) { /* It is a loose reference. */ strbuf_reset(&sb); files_ref_path(refs, &sb, lock->ref_name); if (unlink_or_msg(sb.buf, err)) { ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } update->flags |= REF_DELETED_LOOSE; } if (!(update->flags & REF_ISPRUNING)) string_list_append(&refs_to_delete, lock->ref_name); } } if (repack_without_refs(refs, &refs_to_delete, err)) { ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } /* Delete the reflogs of any references that were deleted: */ for_each_string_list_item(ref_to_delete, &refs_to_delete) { strbuf_reset(&sb); files_reflog_path(refs, &sb, ref_to_delete->string); if (!unlink_or_warn(sb.buf)) try_remove_empty_parents(refs, ref_to_delete->string, REMOVE_EMPTY_PARENTS_REFLOG); } clear_loose_ref_cache(refs); cleanup: files_transaction_cleanup(transaction); strbuf_release(&sb); for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; if (update->flags & REF_DELETED_LOOSE) { /* * The loose reference was deleted. Delete any * empty parent directories. (Note that this * can only work because we have already * removed the lockfile.) */ try_remove_empty_parents(refs, update->refname, REMOVE_EMPTY_PARENTS_REF); } } string_list_clear(&refs_to_delete, 0); free(head_ref); string_list_clear(&affected_refnames, 0); return ret; } static int ref_present(const char *refname, const struct object_id *oid, int flags, void *cb_data) { struct string_list *affected_refnames = cb_data; return string_list_has_string(affected_refnames, refname); } static int files_initial_transaction_commit(struct ref_store *ref_store, struct ref_transaction *transaction, struct strbuf *err) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE, "initial_ref_transaction_commit"); size_t i; int ret = 0; struct string_list affected_refnames = STRING_LIST_INIT_NODUP; assert(err); if (transaction->state != REF_TRANSACTION_OPEN) die("BUG: commit called for transaction that is not open"); /* Fail if a refname appears more than once in the transaction: */ for (i = 0; i < transaction->nr; i++) string_list_append(&affected_refnames, transaction->updates[i]->refname); string_list_sort(&affected_refnames); if (ref_update_reject_duplicates(&affected_refnames, err)) { ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } /* * It's really undefined to call this function in an active * repository or when there are existing references: we are * only locking and changing packed-refs, so (1) any * simultaneous processes might try to change a reference at * the same time we do, and (2) any existing loose versions of * the references that we are setting would have precedence * over our values. But some remote helpers create the remote * "HEAD" and "master" branches before calling this function, * so here we really only check that none of the references * that we are creating already exists. */ if (refs_for_each_rawref(&refs->base, ref_present, &affected_refnames)) die("BUG: initial ref transaction called with existing refs"); for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; if ((update->flags & REF_HAVE_OLD) && !is_null_oid(&update->old_oid)) die("BUG: initial ref transaction with old_sha1 set"); if (refs_verify_refname_available(&refs->base, update->refname, &affected_refnames, NULL, err)) { ret = TRANSACTION_NAME_CONFLICT; goto cleanup; } } if (lock_packed_refs(refs, 0)) { strbuf_addf(err, "unable to lock packed-refs file: %s", strerror(errno)); ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; if ((update->flags & REF_HAVE_NEW) && !is_null_oid(&update->new_oid)) add_packed_ref(refs, update->refname, &update->new_oid); } if (commit_packed_refs(refs)) { strbuf_addf(err, "unable to commit packed-refs file: %s", strerror(errno)); ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } cleanup: transaction->state = REF_TRANSACTION_CLOSED; string_list_clear(&affected_refnames, 0); return ret; } struct expire_reflog_cb { unsigned int flags; reflog_expiry_should_prune_fn *should_prune_fn; void *policy_cb; FILE *newlog; struct object_id last_kept_oid; }; static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid, const char *email, timestamp_t timestamp, int tz, const char *message, void *cb_data) { struct expire_reflog_cb *cb = cb_data; struct expire_reflog_policy_cb *policy_cb = cb->policy_cb; if (cb->flags & EXPIRE_REFLOGS_REWRITE) ooid = &cb->last_kept_oid; if ((*cb->should_prune_fn)(ooid, noid, email, timestamp, tz, message, policy_cb)) { if (!cb->newlog) printf("would prune %s", message); else if (cb->flags & EXPIRE_REFLOGS_VERBOSE) printf("prune %s", message); } else { if (cb->newlog) { fprintf(cb->newlog, "%s %s %s %"PRItime" %+05d\t%s", oid_to_hex(ooid), oid_to_hex(noid), email, timestamp, tz, message); oidcpy(&cb->last_kept_oid, noid); } if (cb->flags & EXPIRE_REFLOGS_VERBOSE) printf("keep %s", message); } return 0; } static int files_reflog_expire(struct ref_store *ref_store, const char *refname, const unsigned char *sha1, unsigned int flags, reflog_expiry_prepare_fn prepare_fn, reflog_expiry_should_prune_fn should_prune_fn, reflog_expiry_cleanup_fn cleanup_fn, void *policy_cb_data) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire"); static struct lock_file reflog_lock; struct expire_reflog_cb cb; struct ref_lock *lock; struct strbuf log_file_sb = STRBUF_INIT; char *log_file; int status = 0; int type; struct strbuf err = STRBUF_INIT; struct object_id oid; memset(&cb, 0, sizeof(cb)); cb.flags = flags; cb.policy_cb = policy_cb_data; cb.should_prune_fn = should_prune_fn; /* * The reflog file is locked by holding the lock on the * reference itself, plus we might need to update the * reference if --updateref was specified: */ lock = lock_ref_sha1_basic(refs, refname, sha1, NULL, NULL, REF_NODEREF, &type, &err); if (!lock) { error("cannot lock ref '%s': %s", refname, err.buf); strbuf_release(&err); return -1; } if (!refs_reflog_exists(ref_store, refname)) { unlock_ref(lock); return 0; } files_reflog_path(refs, &log_file_sb, refname); log_file = strbuf_detach(&log_file_sb, NULL); if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) { /* * Even though holding $GIT_DIR/logs/$reflog.lock has * no locking implications, we use the lock_file * machinery here anyway because it does a lot of the * work we need, including cleaning up if the program * exits unexpectedly. */ if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) { struct strbuf err = STRBUF_INIT; unable_to_lock_message(log_file, errno, &err); error("%s", err.buf); strbuf_release(&err); goto failure; } cb.newlog = fdopen_lock_file(&reflog_lock, "w"); if (!cb.newlog) { error("cannot fdopen %s (%s)", get_lock_file_path(&reflog_lock), strerror(errno)); goto failure; } } hashcpy(oid.hash, sha1); (*prepare_fn)(refname, &oid, cb.policy_cb); refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb); (*cleanup_fn)(cb.policy_cb); if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) { /* * It doesn't make sense to adjust a reference pointed * to by a symbolic ref based on expiring entries in * the symbolic reference's reflog. Nor can we update * a reference if there are no remaining reflog * entries. */ int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) && !(type & REF_ISSYMREF) && !is_null_oid(&cb.last_kept_oid); if (close_lock_file(&reflog_lock)) { status |= error("couldn't write %s: %s", log_file, strerror(errno)); } else if (update && (write_in_full(get_lock_file_fd(lock->lk), oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ || write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 || close_ref(lock) < 0)) { status |= error("couldn't write %s", get_lock_file_path(lock->lk)); rollback_lock_file(&reflog_lock); } else if (commit_lock_file(&reflog_lock)) { status |= error("unable to write reflog '%s' (%s)", log_file, strerror(errno)); } else if (update && commit_ref(lock)) { status |= error("couldn't set %s", lock->ref_name); } } free(log_file); unlock_ref(lock); return status; failure: rollback_lock_file(&reflog_lock); free(log_file); unlock_ref(lock); return -1; } static int files_init_db(struct ref_store *ref_store, struct strbuf *err) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE, "init_db"); struct strbuf sb = STRBUF_INIT; /* * Create .git/refs/{heads,tags} */ files_ref_path(refs, &sb, "refs/heads"); safe_create_dir(sb.buf, 1); strbuf_reset(&sb); files_ref_path(refs, &sb, "refs/tags"); safe_create_dir(sb.buf, 1); strbuf_release(&sb); return 0; } struct ref_storage_be refs_be_files = { NULL, "files", files_ref_store_create, files_init_db, files_transaction_commit, files_initial_transaction_commit, files_pack_refs, files_peel_ref, files_create_symref, files_delete_refs, files_rename_ref, files_ref_iterator_begin, files_read_raw_ref, files_reflog_iterator_begin, files_for_each_reflog_ent, files_for_each_reflog_ent_reverse, files_reflog_exists, files_create_reflog, files_delete_reflog, files_reflog_expire };