1/* $NetBSD$ */ 2 3/* OpenLDAP: pkg/ldap/libraries/liblutil/lockf.c,v 1.15.2.5 2010/04/13 20:23:06 kurt Exp */ 4/* This work is part of OpenLDAP Software <http://www.openldap.org/>. 5 * 6 * Copyright 1998-2010 The OpenLDAP Foundation. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted only as authorized by the OpenLDAP 11 * Public License. 12 * 13 * A copy of this license is available in the file LICENSE in the 14 * top-level directory of the distribution or, alternatively, at 15 * <http://www.OpenLDAP.org/license.html>. 16 */ 17 18/* 19 * File Locking Routines 20 * 21 * Implementations (in order of preference) 22 * - lockf 23 * - fcntl 24 * - flock 25 * 26 * Other implementations will be added as needed. 27 * 28 * NOTE: lutil_lockf() MUST block until an exclusive lock is acquired. 29 */ 30 31#include "portable.h" 32 33#include <stdio.h> 34#include <ac/unistd.h> 35 36#undef LOCK_API 37 38#if defined(HAVE_LOCKF) && defined(F_LOCK) 39# define USE_LOCKF 1 40# define LOCK_API "lockf" 41#endif 42 43#if !defined(LOCK_API) && defined(HAVE_FCNTL) 44# ifdef HAVE_FCNTL_H 45# include <fcntl.h> 46# endif 47# ifdef F_WRLCK 48# define USE_FCNTL 1 49# define LOCK_API "fcntl" 50# endif 51#endif 52 53#if !defined(LOCK_API) && defined(HAVE_FLOCK) 54# ifdef HAVE_SYS_FILE_H 55# include <sys/file.h> 56# endif 57# define USE_FLOCK 1 58# define LOCK_API "flock" 59#endif 60 61#if !defined(USE_LOCKF) && !defined(USE_FCNTL) && !defined(USE_FLOCK) 62int lutil_lockf ( int fd ) { 63 fd = fd; 64 return 0; 65} 66 67int lutil_unlockf ( int fd ) { 68 fd = fd; 69 return 0; 70} 71#endif 72 73#ifdef USE_LOCKF 74int lutil_lockf ( int fd ) { 75 /* use F_LOCK instead of F_TLOCK, ie: block */ 76 return lockf( fd, F_LOCK, 0 ); 77} 78 79int lutil_unlockf ( int fd ) { 80 return lockf( fd, F_ULOCK, 0 ); 81} 82#endif 83 84#ifdef USE_FCNTL 85int lutil_lockf ( int fd ) { 86 struct flock file_lock; 87 88 memset( &file_lock, '\0', sizeof( file_lock ) ); 89 file_lock.l_type = F_WRLCK; 90 file_lock.l_whence = SEEK_SET; 91 file_lock.l_start = 0; 92 file_lock.l_len = 0; 93 94 /* use F_SETLKW instead of F_SETLK, ie: block */ 95 return( fcntl( fd, F_SETLKW, &file_lock ) ); 96} 97 98int lutil_unlockf ( int fd ) { 99 struct flock file_lock; 100 101 memset( &file_lock, '\0', sizeof( file_lock ) ); 102 file_lock.l_type = F_UNLCK; 103 file_lock.l_whence = SEEK_SET; 104 file_lock.l_start = 0; 105 file_lock.l_len = 0; 106 107 return( fcntl ( fd, F_SETLKW, &file_lock ) ); 108} 109#endif 110 111#ifdef USE_FLOCK 112int lutil_lockf ( int fd ) { 113 /* use LOCK_EX instead of LOCK_EX|LOCK_NB, ie: block */ 114 return flock( fd, LOCK_EX ); 115} 116 117int lutil_unlockf ( int fd ) { 118 return flock( fd, LOCK_UN ); 119} 120#endif 121