| /* Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "apr_file_info.h" |
| #include "apr_file_io.h" |
| #include "apr_sdbm.h" |
| |
| #include "sdbm_private.h" |
| #include "sdbm_tune.h" |
| |
| /* NOTE: this function may block until it acquires the lock */ |
| APR_DECLARE(apr_status_t) apr_sdbm_lock(apr_sdbm_t *db, int type) |
| { |
| apr_status_t status; |
| int lock_type = type & APR_FLOCK_TYPEMASK; |
| |
| if (!(lock_type == APR_FLOCK_SHARED || lock_type == APR_FLOCK_EXCLUSIVE)) |
| return APR_EINVAL; |
| |
| if (db->flags & SDBM_EXCLUSIVE_LOCK) { |
| ++db->lckcnt; |
| return APR_SUCCESS; |
| } |
| else if (db->flags & SDBM_SHARED_LOCK) { |
| /* |
| * Cannot promote a shared lock to an exlusive lock |
| * in a cross-platform compatibile manner. |
| */ |
| if (type == APR_FLOCK_EXCLUSIVE) |
| return APR_EINVAL; |
| ++db->lckcnt; |
| return APR_SUCCESS; |
| } |
| /* |
| * zero size: either a fresh database, or one with a single, |
| * unsplit data page: dirpage is all zeros. |
| */ |
| if ((status = apr_file_lock(db->dirf, type)) == APR_SUCCESS) |
| { |
| apr_finfo_t finfo; |
| if ((status = apr_file_info_get(&finfo, APR_FINFO_SIZE, db->dirf)) |
| != APR_SUCCESS) { |
| (void) apr_file_unlock(db->dirf); |
| return status; |
| } |
| |
| SDBM_INVALIDATE_CACHE(db, finfo); |
| |
| ++db->lckcnt; |
| if (type == APR_FLOCK_SHARED) |
| db->flags |= SDBM_SHARED_LOCK; |
| else if (type == APR_FLOCK_EXCLUSIVE) |
| db->flags |= SDBM_EXCLUSIVE_LOCK; |
| } |
| return status; |
| } |
| |
| APR_DECLARE(apr_status_t) apr_sdbm_unlock(apr_sdbm_t *db) |
| { |
| if (!(db->flags & (SDBM_SHARED_LOCK | SDBM_EXCLUSIVE_LOCK))) |
| return APR_EINVAL; |
| if (--db->lckcnt > 0) |
| return APR_SUCCESS; |
| db->flags &= ~(SDBM_SHARED_LOCK | SDBM_EXCLUSIVE_LOCK); |
| return apr_file_unlock(db->dirf); |
| } |