path: root/locks/unix/locks.c

/* ====================================================================
 * Copyright (c) 1999 The Apache Group.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the Apache Group
 *    for use in the Apache HTTP server project (http://www.apache.org/)."
 *
 * 4. The names "Apache Server" and "Apache Group" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the Apache Group
 *    for use in the Apache HTTP server project (http://www.apache.org/)."
 *
 * THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE APACHE GROUP OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Group.
 * For more information on the Apache Group and the Apache HTTP server
 * project, please see <http://www.apache.org/>.
 *
 */

#include "apr_general.h"
#include "apr_portable.h"
#include "locks.h"
#include <string.h>

/* ***APRDOC********************************************************
 * ap_status_t ap_create_lock(ap_context_t *, ap_locktype_e, char *, 
 *                            ap_lock_t **)
 *    Create a new instance of a lock structure. 
 * arg 1) The context to operate on.
 * arg 2) The type of lock to create, one of:
 *            APR_CROSS_PROCESS -- lock processes from the protected area.
 *            APR_INTRAPROCESS  -- lock threads from the protected area.
 *            APR_LOCKALL       -- lock processes and threads from the
 *                                 protected area.
 * arg 3) A file name to use if the lock mechanism requires one.  This
 *        argument should always be provided.  The lock code itself will
 *        determine if it should be used.
 * arg 4) The newly created lock structure.
 * NOTE:  APR_CROSS_PROCESS may lock both processes and threads, but it is
 *        only garaunteed to lock processes.
 */
ap_status_t ap_create_lock(ap_context_t *cont, ap_locktype_e type, char *fname, struct lock_t **lock)
{
    struct lock_t *new;
    ap_status_t stat;

    new = (struct lock_t *)ap_palloc(cont, sizeof(struct lock_t));

    new->cntxt = cont;
    new->type = type;
    new->fname = strdup(fname);

    if (type != APR_CROSS_PROCESS) {
        if ((stat = create_intra_lock(new)) != APR_SUCCESS) {
            return stat;
        }
    }
    if (type != APR_INTRAPROCESS) {
        if ((stat = create_inter_lock(new)) != APR_SUCCESS) {
            return stat;
        }
    }
    *lock = new;
    return APR_SUCCESS;
}

/* ***APRDOC********************************************************
 * ap_status_t ap_lock(ap_lock_t *)
 *    Lock a protected region. 
 * arg 1) The lock to set.
 */
ap_status_t ap_lock(struct lock_t *lock)
{
    ap_status_t stat;
    if (lock->type != APR_CROSS_PROCESS) {
        if ((stat = lock_intra(lock)) != APR_SUCCESS) {
            return stat;
        }
    }
    if (lock->type != APR_INTRAPROCESS) {
        if ((stat = lock_inter(lock)) != APR_SUCCESS) {
            return stat;
        }
    }
    return APR_SUCCESS;
}

/* ***APRDOC********************************************************
 * ap_status_t ap_unlock(ap_lock_t *)
 *    Unlock a protected region. 
 * arg 1) The lock to reset.
 */
ap_status_t ap_unlock(struct lock_t *lock)
{
    ap_status_t stat;

    if (lock->type != APR_CROSS_PROCESS) {
        if ((stat = unlock_intra(lock)) != APR_SUCCESS) {
            return stat;
        }
    }
    if (lock->type != APR_INTRAPROCESS) {
        if ((stat = unlock_inter(lock)) != APR_SUCCESS) {
            return stat;
        }
    }
    return APR_SUCCESS;
}

/* ***APRDOC********************************************************
 * ap_status_t ap_destroy_lock(ap_lock_t *)
 *    Free the memory associated with a lock. 
 * arg 1) The lock to free.
 * NOTE:  If the lock is currently active when it is destroyed, it 
 *        will be unlocked first.
 */
ap_status_t ap_destroy_lock(struct lock_t *lock)
{
    ap_status_t stat;
    if (lock->type != APR_CROSS_PROCESS) {
        if ((stat = destroy_intra_lock(lock)) != APR_SUCCESS) {
            return stat;
        }
    }
    if (lock->type != APR_INTRAPROCESS) {
        if ((stat = destroy_inter_lock(lock)) != APR_SUCCESS) {
            return stat;
        }
    }
    return APR_SUCCESS;
}

/* ***APRDOC********************************************************
 * ap_status_t ap_child_init_lock(ap_context_t *, char *, ap_lock_t **)
 *    Re-open a lock in a child process. 
 * arg 1) The context to operate on.
 * arg 2) A file name to use if the lock mechanism requires one.  This
 *        argument should always be provided.  The lock code itself will
 *        determine if it should be used.  This filename should be the same
 *        one that was passed to ap_create_lock
 * arg 1) The newly re-opened lock structure.
 * NOTE:  This function doesn't always do something, it depends on the
 *        locking mechanism chosen for the platform, but it is a good
 *        idea to call it regardless, because it makes the code more
 *        portable. 
 */
ap_status_t ap_child_init_lock(ap_context_t *cont, char *fname, struct lock_t **lock)
{
    ap_status_t stat;
    if ((*lock)->type != APR_CROSS_PROCESS) {
        if ((stat = child_init_lock(cont, fname, lock)) != APR_SUCCESS) {
            return stat;
        }
    }
    return APR_SUCCESS;
}

/* ***APRDOC********************************************************
 * ap_status_t ap_get_lockdata(ap_lock_t *, void *)
 *    Return the context associated with the current lock.
 * arg 1) The currently open lock.
 * arg 2) The user data associated with the lock.
 */
ap_status_t ap_get_lockdata(struct lock_t *lock, void *data)
{
    if (lock != NULL) {
        return ap_get_userdata(lock->cntxt, &data);
    }
    else {
        data = NULL;
        return APR_ENOLOCK;
    }
}

/* ***APRDOC********************************************************
 * ap_status_t ap_set_lockdata(ap_lock_t *, void *)
 *    Return the context associated with the current lock.
 * arg 1) The currently open lock.
 * arg 2) The user data to associate with the lock.
 */
ap_status_t ap_set_lockdata(struct lock_t *lock, void *data)
{
    if (lock != NULL) {
        return ap_set_userdata(lock->cntxt, data);
    }
    else {
        data = NULL;
        return APR_ENOLOCK;
    }
}

/* ***APRDOC********************************************************
 * ap_status_t ap_get_os_lock(ap_lock_t **, ap_os_lock_t *)
 *    onvert the lock from os specific type to apr type
 * arg 1) The apr lock to convert.
 * arg 2) The os specific lock we are converting to.
 */
ap_status_t ap_get_os_lock(struct lock_t *lock, ap_os_lock_t *oslock)
{
    if (lock == NULL) {
        return APR_ENOLOCK;
    }
    oslock->crossproc = lock->interproc;
#if defined (USE_SYSVSEM_SERIALIZE)
    oslock->op_on = lock->op_on;
    oslock->op_off = lock->op_off;
#elif defined (USE_FCNTL_SERIALIZE)
    oslock->lock_it = lock->lock_it;
    oslock->unlock_it = lock->unlock_it;
#endif
#if defined (USE_PTHREAD_SERIALIZE)
    oslock->intraproc = lock->intraproc;
#endif

    return APR_SUCCESS;
}

/* ***APRDOC********************************************************
 * ap_status_t ap_put_os_lock(ap_context_t *, ap_lock_t **, ap_os_lock_t *)
 *    onvert the lock from os specific type to apr type
 * arg 1) The context to use if it is needed.
 * arg 2) The apr lock we are converting to.
 * arg 3) The os specific lock to convert.
 */
ap_status_t ap_put_os_lock(ap_context_t *cont, struct lock_t **lock, 
                           ap_os_lock_t *thelock)
{
    if (cont == NULL) {
        return APR_ENOCONT;
    }
    if ((*lock) == NULL) {
        (*lock) = (struct lock_t *)ap_palloc(cont, sizeof(struct lock_t));
        (*lock)->cntxt = cont;
    }
    (*lock)->interproc = thelock->crossproc;
#if defined (USE_SYSVSEM_SERIALIZE)
    (*lock)->op_on = thelock->op_on;
    (*lock)->op_off = thelock->op_off;
#elif defined (USE_FCNTL_SERIALIZE)
    (*lock)->lock_it = thelock->lock_it;
    (*lock)->unlock_it = thelock->unlock_it;
#endif
#if defined (USE_PTHREAD_SERIALIZE)
    (*lock)->intraproc = thelock->intraproc;
#endif
    return APR_SUCCESS;
}