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 "namespace.h" 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <unistd.h> 37 #include "un-namespace.h" 38 #include "libc_private.h" 39 40 int 41 lockf(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 (((int (*)(int, int, ...)) 66 *(__libc_interposing_slot(INTERPOS_fcntl))) 67 (filedes, F_GETLK, &fl) == -1) 68 return (-1); 69 if (fl.l_type == F_UNLCK || (fl.l_sysid == 0 && 70 fl.l_pid == getpid())) 71 return (0); 72 errno = EAGAIN; 73 return (-1); 74 /* NOTREACHED */ 75 default: 76 errno = EINVAL; 77 return (-1); 78 /* NOTREACHED */ 79 } 80 81 return (INTERPOS_SYS(fcntl, filedes, cmd, (intptr_t)&fl)); 82 } 83