lockf.c revision 267654
1/* $NetBSD: lockf.c,v 1.3 2008/04/28 20:22:59 martin Exp $ */ 2/*- 3 * Copyright (c) 1997 The NetBSD Foundation, Inc. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to The NetBSD Foundation 7 * by Klaus Klein. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28 * POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31#include <sys/cdefs.h> 32__FBSDID("$FreeBSD: releng/9.3/lib/libc/gen/lockf.c 189328 2009-03-04 01:01:26Z delphij $"); 33 34#include "namespace.h" 35#include <errno.h> 36#include <fcntl.h> 37#include <unistd.h> 38#include "un-namespace.h" 39 40int 41lockf(int filedes, int function, off_t size) 42{ 43 struct flock fl; 44 int cmd; 45 46 fl.l_start = 0; 47 fl.l_len = size; 48 fl.l_whence = SEEK_CUR; 49 50 switch (function) { 51 case F_ULOCK: 52 cmd = F_SETLK; 53 fl.l_type = F_UNLCK; 54 break; 55 case F_LOCK: 56 cmd = F_SETLKW; 57 fl.l_type = F_WRLCK; 58 break; 59 case F_TLOCK: 60 cmd = F_SETLK; 61 fl.l_type = F_WRLCK; 62 break; 63 case F_TEST: 64 fl.l_type = F_WRLCK; 65 if (_fcntl(filedes, F_GETLK, &fl) == -1) 66 return (-1); 67 if (fl.l_type == F_UNLCK || (fl.l_sysid == 0 && fl.l_pid == getpid())) 68 return (0); 69 errno = EAGAIN; 70 return (-1); 71 /* NOTREACHED */ 72 default: 73 errno = EINVAL; 74 return (-1); 75 /* NOTREACHED */ 76 } 77 78 return (_fcntl(filedes, cmd, &fl)); 79} 80