| Darren Tucker | b087998 | 2018-02-26 14:27:02 +1100 | [diff] [blame] | 1 | /* $NetBSD: flock.c,v 1.6 2008/04/28 20:24:12 martin Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 2001 The NetBSD Foundation, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to The NetBSD Foundation |
| 8 | * by Todd Vierling. |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * 1. Redistributions of source code must retain the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer. |
| 15 | * 2. Redistributions in binary form must reproduce the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer in the |
| 17 | * documentation and/or other materials provided with the distribution. |
| 18 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 29 | * POSSIBILITY OF SUCH DAMAGE. |
| 30 | */ |
| 31 | |
| 32 | /* |
| 33 | * Emulate flock() with fcntl(), where available. |
| 34 | * Otherwise, don't do locking; just pretend success. |
| 35 | */ |
| 36 | |
| Darren Tucker | cd3ab57 | 2018-02-26 14:37:06 +1100 | [diff] [blame] | 37 | #include "includes.h" |
| Darren Tucker | b087998 | 2018-02-26 14:27:02 +1100 | [diff] [blame] | 38 | |
| Darren Tucker | cd3ab57 | 2018-02-26 14:37:06 +1100 | [diff] [blame] | 39 | #ifndef HAVE_FLOCK |
| Darren Tucker | b087998 | 2018-02-26 14:27:02 +1100 | [diff] [blame] | 40 | #include <errno.h> |
| 41 | #include <fcntl.h> |
| 42 | |
| Darren Tucker | cd3ab57 | 2018-02-26 14:37:06 +1100 | [diff] [blame] | 43 | int |
| 44 | flock(int fd, int op) |
| 45 | { |
| Darren Tucker | b087998 | 2018-02-26 14:27:02 +1100 | [diff] [blame] | 46 | int rc = 0; |
| 47 | |
| 48 | #if defined(F_SETLK) && defined(F_SETLKW) |
| 49 | struct flock fl = {0}; |
| 50 | |
| 51 | switch (op & (LOCK_EX|LOCK_SH|LOCK_UN)) { |
| 52 | case LOCK_EX: |
| 53 | fl.l_type = F_WRLCK; |
| 54 | break; |
| 55 | |
| 56 | case LOCK_SH: |
| 57 | fl.l_type = F_RDLCK; |
| 58 | break; |
| 59 | |
| 60 | case LOCK_UN: |
| 61 | fl.l_type = F_UNLCK; |
| 62 | break; |
| 63 | |
| 64 | default: |
| 65 | errno = EINVAL; |
| 66 | return -1; |
| 67 | } |
| 68 | |
| 69 | fl.l_whence = SEEK_SET; |
| 70 | rc = fcntl(fd, op & LOCK_NB ? F_SETLK : F_SETLKW, &fl); |
| 71 | |
| 72 | if (rc && (errno == EAGAIN)) |
| 73 | errno = EWOULDBLOCK; |
| Darren Tucker | cd3ab57 | 2018-02-26 14:37:06 +1100 | [diff] [blame] | 74 | #else |
| Darren Tucker | 5aea4aa | 2018-02-26 14:39:14 +1100 | [diff] [blame] | 75 | rc = -1; |
| Darren Tucker | cd3ab57 | 2018-02-26 14:37:06 +1100 | [diff] [blame] | 76 | errno = ENOSYS; |
| Darren Tucker | b087998 | 2018-02-26 14:27:02 +1100 | [diff] [blame] | 77 | #endif |
| 78 | |
| 79 | return rc; |
| 80 | } |
| 81 | #endif |