amflock-posix.c

开源备份软件源码 AMANDA, the Advanced Maryland Automatic Network Disk Archiver, is a backup system that a

/*
 * Amanda, The Advanced Maryland Automatic Network Disk Archiver
 * Copyright (c) 1991-1998 University of Maryland at College Park
 * All Rights Reserved.
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation, and that the name of U.M. not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  U.M. makes no representations about the
 * suitability of this software for any purpose.  It is provided "as is"
 * without express or implied warranty.
 *
 * U.M. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL U.M.
 * BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Authors: the Amanda Development Team.  Its members are listed in a
 * file named AUTHORS, in the root directory of this distribution.
 */

/* moved from amflock.c by Dustin J. Mitchell <[e-mail]> */

#include "amanda.h"

static int
posix_lock(
    int	fd,
    G_GNUC_UNUSED char *resource)
{
    struct flock lock;

    lock.l_type = F_WRLCK;
    lock.l_start = 0;
    lock.l_whence = SEEK_SET;
    lock.l_len = 0; /* to EOF */
    return fcntl(fd, F_SETLKW, &lock);
}

static int
posix_rolock(
    int	fd,
    G_GNUC_UNUSED char *resource)
{
    struct flock lock;

    lock.l_type = F_RDLCK;
    lock.l_start = 0;
    lock.l_whence = SEEK_SET;
    lock.l_len = 0; /* to EOF */
    return fcntl(fd, F_SETLKW, &lock);
}

static int
posix_unlock(
    int	fd,
    G_GNUC_UNUSED char *resource)
{
    struct flock lock;

    lock.l_type = F_UNLCK;
    lock.l_start = 0;
    lock.l_whence = SEEK_SET;
    lock.l_len = 0; /* to EOF */
    return fcntl(fd, F_SETLK, &lock);
}

amflock_impl_t amflock_posix_impl = {
    posix_lock,
    posix_rolock,
    posix_unlock,
    "posix"
};