lockf.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (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 1989 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1984 AT&T */
/* All Rights Reserved */
#pragma ident "%Z%%M% %I% %E% SMI"
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/syscall.h>
/*
* convert lockf() into fcntl() for SystemV compatibility
*/
/* New SVR4 values */
#define SV_GETLK 5
#define SV_SETLK 6
#define SV_SETLKW 7
lockf(fildes, function, size)
int fildes;
int function;
long size;
{
struct flock ld;
register int cmd;
cmd = SV_SETLK; /* assume non-blocking operation */
ld.l_type = F_WRLCK; /* lockf() only deals with exclusive locks */
ld.l_whence = 1; /* lock always starts at current position */
if (size < 0) {
ld.l_start = size;
ld.l_len = -size;
} else {
ld.l_start = 0L;
ld.l_len = size;
}
switch (function) {
case F_TEST:
if (_syscall(SYS_fcntl, fildes, SV_GETLK, &ld) != -1) {
if (ld.l_type == F_UNLCK) {
ld.l_pid = ld.l_xxx;
/* l_pid is the last field in the
SVr3 flock structure */
return (0);
} else
errno = EACCES; /* EAGAIN ?? */
}
return (-1);
default:
errno = EINVAL;
return (-1);
/* the rest fall thru to the fcntl() at the end */
case F_ULOCK:
ld.l_type = F_UNLCK;
break;
case F_LOCK:
cmd = SV_SETLKW; /* block, if not available */
break;
case F_TLOCK:
break;
}
if (_syscall(SYS_fcntl, fildes, cmd, &ld) == -1) {
switch (errno) {
/* this hack is purported to be for /usr/group compatibility */
case ENOLCK:
errno = EDEADLK;
}
return(-1);
} else {
ld.l_pid = ld.l_xxx; /* l_pid is the last field in the
SVr3 flock structure */
return(0);
}
}