1 /* 2 * Copyright (c) 1995, 1996, 1997 Kungliga Tekniska H�gskolan 3 * (Royal Institute of Technology, Stockholm, Sweden). 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * 3. Neither the name of the Institute nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifdef HAVE_CONFIG_H 35 #include <config.h> 36 #endif 37 38 #ifndef HAVE_FLOCK 39 RCSID("$Id: flock.c,v 1.4 1999/12/02 16:58:46 joda Exp $"); 40 41 #include "roken.h" 42 43 44 #define OP_MASK (LOCK_SH | LOCK_EX | LOCK_UN) 45 46 int 47 flock(int fd, int operation) 48 { 49 #if defined(HAVE_FCNTL) && defined(F_SETLK) 50 struct flock arg; 51 int code, cmd; 52 53 arg.l_whence = SEEK_SET; 54 arg.l_start = 0; 55 arg.l_len = 0; /* means to EOF */ 56 57 if (operation & LOCK_NB) 58 cmd = F_SETLK; 59 else 60 cmd = F_SETLKW; /* Blocking */ 61 62 switch (operation & OP_MASK) { 63 case LOCK_UN: 64 arg.l_type = F_UNLCK; 65 code = fcntl(fd, F_SETLK, &arg); 66 break; 67 case LOCK_SH: 68 arg.l_type = F_RDLCK; 69 code = fcntl(fd, cmd, &arg); 70 break; 71 case LOCK_EX: 72 arg.l_type = F_WRLCK; 73 code = fcntl(fd, cmd, &arg); 74 break; 75 default: 76 errno = EINVAL; 77 code = -1; 78 break; 79 } 80 return code; 81 #else 82 return -1; 83 #endif 84 } 85 86 #endif 87 88