diff options
Diffstat (limited to 'refs.c')
| -rw-r--r-- | refs.c | 422 |
1 files changed, 280 insertions, 142 deletions
@@ -58,6 +58,12 @@ static unsigned char refname_disposition[256] = { #define REF_HAVE_OLD 0x10 /* + * Used as a flag in ref_update::flags when the lockfile needs to be + * committed. + */ +#define REF_NEEDS_COMMIT 0x20 + +/* * Try to read one refname component from the front of refname. * Return the length of the component found, or -1 if the component is * not legal. It is legal if it is something reasonable to have under @@ -263,7 +269,7 @@ struct ref_dir { * presence of an empty subdirectory does not block the creation of a * similarly-named reference. (The fact that reference names with the * same leading components can conflict *with each other* is a - * separate issue that is regulated by is_refname_available().) + * separate issue that is regulated by verify_refname_available().) * * Please note that the name field contains the fully-qualified * reference (or subdirectory) name. Space could be saved by only @@ -841,121 +847,181 @@ static void prime_ref_dir(struct ref_dir *dir) } } -static int entry_matches(struct ref_entry *entry, const struct string_list *list) -{ - return list && string_list_has_string(list, entry->name); -} - struct nonmatching_ref_data { const struct string_list *skip; - struct ref_entry *found; + const char *conflicting_refname; }; static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata) { struct nonmatching_ref_data *data = vdata; - if (entry_matches(entry, data->skip)) + if (data->skip && string_list_has_string(data->skip, entry->name)) return 0; - data->found = entry; + data->conflicting_refname = entry->name; return 1; } -static void report_refname_conflict(struct ref_entry *entry, - const char *refname) -{ - error("'%s' exists; cannot create '%s'", entry->name, refname); -} - /* - * Return true iff a reference named refname could be created without - * conflicting with the name of an existing reference in dir. If - * skip is non-NULL, ignore potential conflicts with refs in skip - * (e.g., because they are scheduled for deletion in the same - * operation). + * Return 0 if a reference named refname could be created without + * conflicting with the name of an existing reference in dir. + * Otherwise, return a negative value and write an explanation to err. + * If extras is non-NULL, it is a list of additional refnames with + * which refname is not allowed to conflict. If skip is non-NULL, + * ignore potential conflicts with refs in skip (e.g., because they + * are scheduled for deletion in the same operation). Behavior is + * undefined if the same name is listed in both extras and skip. * * Two reference names conflict if one of them exactly matches the - * leading components of the other; e.g., "foo/bar" conflicts with - * both "foo" and with "foo/bar/baz" but not with "foo/bar" or - * "foo/barbados". + * leading components of the other; e.g., "refs/foo/bar" conflicts + * with both "refs/foo" and with "refs/foo/bar/baz" but not with + * "refs/foo/bar" or "refs/foo/barbados". * - * skip must be sorted. + * extras and skip must be sorted. */ -static int is_refname_available(const char *refname, - const struct string_list *skip, - struct ref_dir *dir) +static int verify_refname_available(const char *refname, + const struct string_list *extras, + const struct string_list *skip, + struct ref_dir *dir, + struct strbuf *err) { const char *slash; - size_t len; int pos; - char *dirname; + struct strbuf dirname = STRBUF_INIT; + int ret = -1; + + /* + * For the sake of comments in this function, suppose that + * refname is "refs/foo/bar". + */ + + assert(err); + strbuf_grow(&dirname, strlen(refname) + 1); for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) { + /* Expand dirname to the new prefix, not including the trailing slash: */ + strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len); + /* - * We are still at a leading dir of the refname; we are - * looking for a conflict with a leaf entry. - * - * If we find one, we still must make sure it is - * not in "skip". + * We are still at a leading dir of the refname (e.g., + * "refs/foo"; if there is a reference with that name, + * it is a conflict, *unless* it is in skip. */ - pos = search_ref_dir(dir, refname, slash - refname); - if (pos >= 0) { - struct ref_entry *entry = dir->entries[pos]; - if (entry_matches(entry, skip)) - return 1; - report_refname_conflict(entry, refname); - return 0; + if (dir) { + pos = search_ref_dir(dir, dirname.buf, dirname.len); + if (pos >= 0 && + (!skip || !string_list_has_string(skip, dirname.buf))) { + /* + * We found a reference whose name is + * a proper prefix of refname; e.g., + * "refs/foo", and is not in skip. + */ + strbuf_addf(err, "'%s' exists; cannot create '%s'", + dirname.buf, refname); + goto cleanup; + } } + if (extras && string_list_has_string(extras, dirname.buf) && + (!skip || !string_list_has_string(skip, dirname.buf))) { + strbuf_addf(err, "cannot process '%s' and '%s' at the same time", + refname, dirname.buf); + goto cleanup; + } /* * Otherwise, we can try to continue our search with - * the next component; if we come up empty, we know - * there is nothing under this whole prefix. + * the next component. So try to look up the + * directory, e.g., "refs/foo/". If we come up empty, + * we know there is nothing under this whole prefix, + * but even in that case we still have to continue the + * search for conflicts with extras. */ - pos = search_ref_dir(dir, refname, slash + 1 - refname); - if (pos < 0) - return 1; - - dir = get_ref_dir(dir->entries[pos]); + strbuf_addch(&dirname, '/'); + if (dir) { + pos = search_ref_dir(dir, dirname.buf, dirname.len); + if (pos < 0) { + /* + * There was no directory "refs/foo/", + * so there is nothing under this + * whole prefix. So there is no need + * to continue looking for conflicting + * references. But we need to continue + * looking for conflicting extras. + */ + dir = NULL; + } else { + dir = get_ref_dir(dir->entries[pos]); + } + } } /* - * We are at the leaf of our refname; we want to - * make sure there are no directories which match it. + * We are at the leaf of our refname (e.g., "refs/foo/bar"). + * There is no point in searching for a reference with that + * name, because a refname isn't considered to conflict with + * itself. But we still need to check for references whose + * names are in the "refs/foo/bar/" namespace, because they + * *do* conflict. */ - len = strlen(refname); - dirname = xmallocz(len + 1); - sprintf(dirname, "%s/", refname); - pos = search_ref_dir(dir, dirname, len + 1); - free(dirname); + strbuf_addstr(&dirname, refname + dirname.len); + strbuf_addch(&dirname, '/'); + + if (dir) { + pos = search_ref_dir(dir, dirname.buf, dirname.len); - if (pos >= 0) { + if (pos >= 0) { + /* + * We found a directory named "$refname/" + * (e.g., "refs/foo/bar/"). It is a problem + * iff it contains any ref that is not in + * "skip". + */ + struct nonmatching_ref_data data; + + data.skip = skip; + data.conflicting_refname = NULL; + dir = get_ref_dir(dir->entries[pos]); + sort_ref_dir(dir); + if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) { + strbuf_addf(err, "'%s' exists; cannot create '%s'", + data.conflicting_refname, refname); + goto cleanup; + } + } + } + + if (extras) { /* - * We found a directory named "refname". It is a - * problem iff it contains any ref that is not - * in "skip". + * Check for entries in extras that start with + * "$refname/". We do that by looking for the place + * where "$refname/" would be inserted in extras. If + * there is an entry at that position that starts with + * "$refname/" and is not in skip, then we have a + * conflict. */ - struct ref_entry *entry = dir->entries[pos]; - struct ref_dir *dir = get_ref_dir(entry); - struct nonmatching_ref_data data; + for (pos = string_list_find_insert_index(extras, dirname.buf, 0); + pos < extras->nr; pos++) { + const char *extra_refname = extras->items[pos].string; - data.skip = skip; - sort_ref_dir(dir); - if (!do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) - return 1; + if (!starts_with(extra_refname, dirname.buf)) + break; - report_refname_conflict(data.found, refname); - return 0; + if (!skip || !string_list_has_string(skip, extra_refname)) { + strbuf_addf(err, "cannot process '%s' and '%s' at the same time", + refname, extra_refname); + goto cleanup; + } + } } - /* - * There is no point in searching for another leaf - * node which matches it; such an entry would be the - * ref we are looking for, not a conflict. - */ - return 1; + /* No conflicts were found */ + ret = 0; + +cleanup: + strbuf_release(&dirname); + return ret; } struct packed_ref_cache { @@ -2271,8 +2337,10 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log) */ static struct ref_lock *lock_ref_sha1_basic(const char *refname, const unsigned char *old_sha1, + const struct string_list *extras, const struct string_list *skip, - unsigned int flags, int *type_p) + unsigned int flags, int *type_p, + struct strbuf *err) { char *ref_file; const char *orig_refname = refname; @@ -2283,6 +2351,8 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname, int resolve_flags = 0; int attempts_remaining = 3; + assert(err); + lock = xcalloc(1, sizeof(struct ref_lock)); lock->lock_fd = -1; @@ -2305,7 +2375,12 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname, ref_file = git_path("%s", orig_refname); if (remove_empty_directories(ref_file)) { last_errno = errno; - error("there are still refs under '%s'", orig_refname); + + if (!verify_refname_available(orig_refname, extras, skip, + get_loose_refs(&ref_cache), err)) + strbuf_addf(err, "there are still refs under '%s'", + orig_refname); + goto error_return; } refname = resolve_ref_unsafe(orig_refname, resolve_flags, @@ -2315,8 +2390,12 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname, *type_p = type; if (!refname) { last_errno = errno; - error("unable to resolve reference %s: %s", - orig_refname, strerror(errno)); + if (last_errno != ENOTDIR || + !verify_refname_available(orig_refname, extras, skip, + get_loose_refs(&ref_cache), err)) + strbuf_addf(err, "unable to resolve reference %s: %s", + orig_refname, strerror(last_errno)); + goto error_return; } /* @@ -2326,7 +2405,8 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname, * our refname. */ if (is_null_sha1(lock->old_sha1) && - !is_refname_available(refname, skip, get_packed_refs(&ref_cache))) { + verify_refname_available(refname, extras, skip, + get_packed_refs(&ref_cache), err)) { last_errno = ENOTDIR; goto error_return; } @@ -2352,7 +2432,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname, /* fall through */ default: last_errno = errno; - error("unable to create directory for %s", ref_file); + strbuf_addf(err, "unable to create directory for %s", ref_file); goto error_return; } @@ -2367,10 +2447,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname, */ goto retry; else { - struct strbuf err = STRBUF_INIT; - unable_to_lock_message(ref_file, errno, &err); - error("%s", err.buf); - strbuf_release(&err); + unable_to_lock_message(ref_file, errno, err); goto error_return; } } @@ -2764,17 +2841,25 @@ static int rename_tmp_log(const char *newrefname) static int rename_ref_available(const char *oldname, const char *newname) { struct string_list skip = STRING_LIST_INIT_NODUP; + struct strbuf err = STRBUF_INIT; int ret; string_list_insert(&skip, oldname); - ret = is_refname_available(newname, &skip, get_packed_refs(&ref_cache)) - && is_refname_available(newname, &skip, get_loose_refs(&ref_cache)); + ret = !verify_refname_available(newname, NULL, &skip, + get_packed_refs(&ref_cache), &err) + && !verify_refname_available(newname, NULL, &skip, + get_loose_refs(&ref_cache), &err); + if (!ret) + error("%s", err.buf); + string_list_clear(&skip, 0); + strbuf_release(&err); return ret; } -static int write_ref_sha1(struct ref_lock *lock, const unsigned char *sha1, - const char *logmsg); +static int write_ref_to_lockfile(struct ref_lock *lock, const unsigned char *sha1); +static int commit_ref_update(struct ref_lock *lock, + const unsigned char *sha1, const char *logmsg); int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg) { @@ -2784,6 +2869,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms struct stat loginfo; int log = !lstat(git_path("logs/%s", oldrefname), &loginfo); const char *symref = NULL; + struct strbuf err = STRBUF_INIT; if (log && S_ISLNK(loginfo.st_mode)) return error("reflog for %s is a symlink", oldrefname); @@ -2826,13 +2912,16 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms logmoved = log; - lock = lock_ref_sha1_basic(newrefname, NULL, NULL, 0, NULL); + lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, 0, NULL, &err); if (!lock) { - error("unable to lock %s for update", newrefname); + error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf); + strbuf_release(&err); goto rollback; } hashcpy(lock->old_sha1, orig_sha1); - if (write_ref_sha1(lock, orig_sha1, logmsg)) { + + if (write_ref_to_lockfile(lock, orig_sha1) || + commit_ref_update(lock, orig_sha1, logmsg)) { error("unable to write current sha1 into %s", newrefname); goto rollback; } @@ -2840,15 +2929,17 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms return 0; rollback: - lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, 0, NULL); + lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, 0, NULL, &err); if (!lock) { - error("unable to lock %s for rollback", oldrefname); + 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 = 0; - if (write_ref_sha1(lock, orig_sha1, NULL)) + if (write_ref_to_lockfile(lock, orig_sha1) || + commit_ref_update(lock, orig_sha1, NULL)) error("unable to write current sha1 into %s", oldrefname); log_all_ref_updates = flag; @@ -3022,11 +3113,11 @@ int is_branch(const char *refname) } /* - * Write sha1 into the ref specified by the lock. Make sure that errno - * is sane on error. + * Write sha1 into the open lockfile, then close the lockfile. On + * errors, rollback the lockfile and set errno to reflect the problem. */ -static int write_ref_sha1(struct ref_lock *lock, - const unsigned char *sha1, const char *logmsg) +static int write_ref_to_lockfile(struct ref_lock *lock, + const unsigned char *sha1) { static char term = '\n'; struct object *o; @@ -3055,6 +3146,17 @@ static int write_ref_sha1(struct ref_lock *lock, errno = save_errno; 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 ref_lock *lock, + const unsigned char *sha1, const char *logmsg) +{ clear_loose_ref_cache(&ref_cache); if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 || (strcmp(lock->ref_name, lock->orig_ref_name) && @@ -3695,25 +3797,18 @@ int update_ref(const char *msg, const char *refname, return 0; } -static int ref_update_compare(const void *r1, const void *r2) -{ - const struct ref_update * const *u1 = r1; - const struct ref_update * const *u2 = r2; - return strcmp((*u1)->refname, (*u2)->refname); -} - -static int ref_update_reject_duplicates(struct ref_update **updates, int n, +static int ref_update_reject_duplicates(struct string_list *refnames, struct strbuf *err) { - int i; + int i, n = refnames->nr; assert(err); for (i = 1; i < n; i++) - if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) { + if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) { strbuf_addf(err, "Multiple updates for ref '%s' not allowed.", - updates[i]->refname); + refnames->items[i].string); return 1; } return 0; @@ -3727,6 +3822,7 @@ int ref_transaction_commit(struct ref_transaction *transaction, struct ref_update **updates = transaction->updates; 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; assert(err); @@ -3738,63 +3834,101 @@ int ref_transaction_commit(struct ref_transaction *transaction, return 0; } - /* Copy, sort, and reject duplicate refs */ - qsort(updates, n, sizeof(*updates), ref_update_compare); - if (ref_update_reject_duplicates(updates, n, err)) { + /* Fail if a refname appears more than once in the transaction: */ + for (i = 0; i < n; i++) + string_list_append(&affected_refnames, updates[i]->refname); + string_list_sort(&affected_refnames); + if (ref_update_reject_duplicates(&affected_refnames, err)) { ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } - /* Acquire all locks while verifying old values */ + /* + * 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 < n; i++) { struct ref_update *update = updates[i]; - unsigned int flags = update->flags; - if ((flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1)) - flags |= REF_DELETING; + if ((update->flags & REF_HAVE_NEW) && + is_null_sha1(update->new_sha1)) + update->flags |= REF_DELETING; update->lock = lock_ref_sha1_basic( update->refname, ((update->flags & REF_HAVE_OLD) ? update->old_sha1 : NULL), - NULL, - flags, - &update->type); + &affected_refnames, NULL, + update->flags, + &update->type, + err); if (!update->lock) { + char *reason; + ret = (errno == ENOTDIR) ? TRANSACTION_NAME_CONFLICT : TRANSACTION_GENERIC_ERROR; - strbuf_addf(err, "Cannot lock the ref '%s'.", - update->refname); + reason = strbuf_detach(err, NULL); + strbuf_addf(err, "Cannot lock ref '%s': %s", + update->refname, reason); + free(reason); goto cleanup; } - } - - /* Perform updates first so live commits remain referenced */ - for (i = 0; i < n; i++) { - struct ref_update *update = updates[i]; - int flags = update->flags; - - if ((flags & REF_HAVE_NEW) && !is_null_sha1(update->new_sha1)) { + if ((update->flags & REF_HAVE_NEW) && + !(update->flags & REF_DELETING)) { int overwriting_symref = ((update->type & REF_ISSYMREF) && (update->flags & REF_NODEREF)); - if (!overwriting_symref - && !hashcmp(update->lock->old_sha1, update->new_sha1)) { + if (!overwriting_symref && + !hashcmp(update->lock->old_sha1, update->new_sha1)) { /* * The reference already has the desired * value, so we don't need to write it. */ - unlock_ref(update->lock); + } else if (write_ref_to_lockfile(update->lock, + update->new_sha1)) { + /* + * The lock was freed upon failure of + * write_ref_to_lockfile(): + */ update->lock = NULL; - } else if (write_ref_sha1(update->lock, update->new_sha1, - update->msg)) { - update->lock = NULL; /* freed by write_ref_sha1 */ strbuf_addf(err, "Cannot update the ref '%s'.", update->refname); ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } else { - /* freed by write_ref_sha1(): */ + update->flags |= REF_NEEDS_COMMIT; + } + } + if (!(update->flags & REF_NEEDS_COMMIT)) { + /* + * We didn't have to write anything to the lockfile. + * Close it to free up the file descriptor: + */ + if (close_ref(update->lock)) { + strbuf_addf(err, "Couldn't close %s.lock", + update->refname); + goto cleanup; + } + } + } + + /* Perform updates first so live commits remain referenced */ + for (i = 0; i < n; i++) { + struct ref_update *update = updates[i]; + + if (update->flags & REF_NEEDS_COMMIT) { + if (commit_ref_update(update->lock, + update->new_sha1, update->msg)) { + /* freed by commit_ref_update(): */ + update->lock = NULL; + strbuf_addf(err, "Cannot update the ref '%s'.", + update->refname); + ret = TRANSACTION_GENERIC_ERROR; + goto cleanup; + } else { + /* freed by commit_ref_update(): */ update->lock = NULL; } } @@ -3803,15 +3937,14 @@ int ref_transaction_commit(struct ref_transaction *transaction, /* Perform deletes now that updates are safely completed */ for (i = 0; i < n; i++) { struct ref_update *update = updates[i]; - int flags = update->flags; - if ((flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1)) { + if (update->flags & REF_DELETING) { if (delete_ref_loose(update->lock, update->type, err)) { ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } - if (!(flags & REF_ISPRUNING)) + if (!(update->flags & REF_ISPRUNING)) string_list_append(&refs_to_delete, update->lock->ref_name); } @@ -3832,6 +3965,7 @@ cleanup: if (updates[i]->lock) unlock_ref(updates[i]->lock); string_list_clear(&refs_to_delete, 0); + string_list_clear(&affected_refnames, 0); return ret; } @@ -4021,6 +4155,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1, char *log_file; int status = 0; int type; + struct strbuf err = STRBUF_INIT; memset(&cb, 0, sizeof(cb)); cb.flags = flags; @@ -4032,9 +4167,12 @@ int reflog_expire(const char *refname, const unsigned char *sha1, * reference itself, plus we might need to update the * reference if --updateref was specified: */ - lock = lock_ref_sha1_basic(refname, sha1, NULL, 0, &type); - if (!lock) - return error("cannot lock ref '%s'", refname); + lock = lock_ref_sha1_basic(refname, sha1, NULL, NULL, 0, &type, &err); + if (!lock) { + error("cannot lock ref '%s': %s", refname, err.buf); + strbuf_release(&err); + return -1; + } if (!reflog_exists(refname)) { unlock_ref(lock); return 0; |