1 /* $NetBSD: lockf.c,v 1.3 2008/04/28 20:22:59 martin Exp $ */ 2 /*- 3 * SPDX-License-Identifier: BSD-2-Clause 4 * 5 * Copyright (c) 1997 The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Klaus Klein. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 #include "namespace.h" 35 #include <errno.h> 36 #include <fcntl.h> 37 #include <unistd.h> 38 #include "un-namespace.h" 39 #include "libc_private.h" 40 41 int 42 lockf(int filedes, int function, off_t size) 43 { 44 struct flock fl; 45 int cmd; 46 47 fl.l_start = 0; 48 fl.l_len = size; 49 fl.l_whence = SEEK_CUR; 50 51 switch (function) { 52 case F_ULOCK: 53 cmd = F_SETLK; 54 fl.l_type = F_UNLCK; 55 break; 56 case F_LOCK: 57 cmd = F_SETLKW; 58 fl.l_type = F_WRLCK; 59 break; 60 case F_TLOCK: 61 cmd = F_SETLK; 62 fl.l_type = F_WRLCK; 63 break; 64 case F_TEST: 65 fl.l_type = F_WRLCK; 66 if (((int (*)(int, int, ...)) 67 __libc_interposing[INTERPOS_fcntl])(filedes, F_GETLK, &fl) 68 == -1) 69 return (-1); 70 if (fl.l_type == F_UNLCK || (fl.l_sysid == 0 && 71 fl.l_pid == getpid())) 72 return (0); 73 errno = EAGAIN; 74 return (-1); 75 /* NOTREACHED */ 76 default: 77 errno = EINVAL; 78 return (-1); 79 /* NOTREACHED */ 80 } 81 82 return (((int (*)(int, int, ...)) 83 __libc_interposing[INTERPOS_fcntl])(filedes, cmd, &fl)); 84 } 85