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/* 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 */
APU_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;
}
APU_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);
}
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