1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ 27 /* All Rights Reserved */ 28 29 /* 30 * Portions of this source code were derived from Berkeley 4.3 BSD 31 * under license from the Regents of the University of California. 32 */ 33 34 /*LINTLIBRARY*/ 35 36 #include <sys/types.h> 37 #include <sys/file.h> 38 #include <sys/fcntl.h> 39 #include <errno.h> 40 41 int 42 flock(int fd, int operation) 43 { 44 struct flock fl; 45 int cmd; 46 int ret; 47 48 /* initialize the flock struct to set lock on entire file */ 49 fl.l_whence = 0; 50 fl.l_start = 0; 51 fl.l_len = 0; 52 fl.l_type = 0; 53 54 /* In non-blocking lock, use F_SETLK for cmd, F_SETLKW otherwise */ 55 if (operation & LOCK_NB) { 56 cmd = F_SETLK; 57 operation &= ~LOCK_NB; /* turn off this bit */ 58 } else 59 cmd = F_SETLKW; 60 61 switch (operation) { 62 case LOCK_UN: 63 fl.l_type |= F_UNLCK; 64 break; 65 case LOCK_SH: 66 fl.l_type |= F_RDLCK; 67 break; 68 case LOCK_EX: 69 fl.l_type |= F_WRLCK; 70 break; 71 default: 72 errno = EINVAL; 73 return (-1); 74 } 75 76 ret = fcntl(fd, cmd, &fl); 77 78 if (ret == -1 && errno == EACCES) 79 errno = EWOULDBLOCK; 80 81 return (ret); 82 } 83