xref: /illumos-gate/usr/src/lib/libc/port/sys/lockf.c (revision 1da57d55)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*	Copyright (c) 1988 AT&T	*/
/*	  All Rights Reserved  	*/

#include <sys/feature_tests.h>

#if !defined(_LP64) && _FILE_OFFSET_BITS == 64
#define	__lockf		__lockf64
#endif

#include "lint.h"
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>

int
__lockf(int fildes, int function, off_t size)
{
	struct flock l;
	int rv;

	l.l_whence = 1;
	if (size < 0) {
		l.l_start = size;
		l.l_len = -size;
	} else {
		l.l_start = (off_t)0;
		l.l_len = size;
	}
	switch (function) {
	case F_ULOCK:
		l.l_type = F_UNLCK;
		rv = fcntl(fildes, F_SETLK, &l);
		break;
	case F_LOCK:
		l.l_type = F_WRLCK;
		rv = fcntl(fildes, F_SETLKW, &l);
		break;
	case F_TLOCK:
		l.l_type = F_WRLCK;
		rv = fcntl(fildes, F_SETLK, &l);
		break;
	case F_TEST:
		l.l_type = F_WRLCK;
		rv = fcntl(fildes, F_GETLK, &l);
		if (rv != -1) {
			if (l.l_type == F_UNLCK)
				return (0);
			else {
				errno = EAGAIN;
				return (-1);
			}
		}
		break;
	default:
		errno = EINVAL;
		return (-1);
	}
	if (rv < 0) {
		switch (errno) {
		case EMFILE:
		case ENOSPC:
		case ENOLCK:
			/*
			 * A deadlock error is given if we run out of resources,
			 * in compliance with /usr/group standards.
			 */
			errno = EDEADLK;
			break;
		default:
			break;
		}
	}
	return (rv);
}