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119 lines
2.4 KiB
C
119 lines
2.4 KiB
C
/* $OpenLDAP$ */
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/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
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*
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* Copyright 1998-2019 The OpenLDAP Foundation.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted only as authorized by the OpenLDAP
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* Public License.
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*
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* A copy of this license is available in the file LICENSE in the
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* top-level directory of the distribution or, alternatively, at
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* <http://www.OpenLDAP.org/license.html>.
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*/
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/*
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* File Locking Routines
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*
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* Implementations (in order of preference)
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* - lockf
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* - fcntl
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* - flock
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*
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* Other implementations will be added as needed.
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*
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* NOTE: lutil_lockf() MUST block until an exclusive lock is acquired.
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*/
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#include "portable.h"
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#include <stdio.h>
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#include <ac/unistd.h>
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#undef LOCK_API
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#if defined(HAVE_LOCKF) && defined(F_LOCK)
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# define USE_LOCKF 1
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# define LOCK_API "lockf"
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#endif
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#if !defined(LOCK_API) && defined(HAVE_FCNTL)
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# ifdef HAVE_FCNTL_H
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# include <fcntl.h>
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# endif
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# ifdef F_WRLCK
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# define USE_FCNTL 1
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# define LOCK_API "fcntl"
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# endif
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#endif
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#if !defined(LOCK_API) && defined(HAVE_FLOCK)
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# ifdef HAVE_SYS_FILE_H
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# include <sys/file.h>
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# endif
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# define USE_FLOCK 1
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# define LOCK_API "flock"
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#endif
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#if !defined(USE_LOCKF) && !defined(USE_FCNTL) && !defined(USE_FLOCK)
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int lutil_lockf ( int fd ) {
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fd = fd;
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return 0;
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}
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int lutil_unlockf ( int fd ) {
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fd = fd;
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return 0;
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}
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#endif
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#ifdef USE_LOCKF
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int lutil_lockf ( int fd ) {
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/* use F_LOCK instead of F_TLOCK, ie: block */
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return lockf( fd, F_LOCK, 0 );
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}
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int lutil_unlockf ( int fd ) {
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return lockf( fd, F_ULOCK, 0 );
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}
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#endif
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#ifdef USE_FCNTL
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int lutil_lockf ( int fd ) {
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struct flock file_lock;
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memset( &file_lock, '\0', sizeof( file_lock ) );
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file_lock.l_type = F_WRLCK;
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file_lock.l_whence = SEEK_SET;
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file_lock.l_start = 0;
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file_lock.l_len = 0;
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/* use F_SETLKW instead of F_SETLK, ie: block */
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return( fcntl( fd, F_SETLKW, &file_lock ) );
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}
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int lutil_unlockf ( int fd ) {
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struct flock file_lock;
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memset( &file_lock, '\0', sizeof( file_lock ) );
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file_lock.l_type = F_UNLCK;
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file_lock.l_whence = SEEK_SET;
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file_lock.l_start = 0;
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file_lock.l_len = 0;
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return( fcntl ( fd, F_SETLKW, &file_lock ) );
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}
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#endif
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#ifdef USE_FLOCK
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int lutil_lockf ( int fd ) {
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/* use LOCK_EX instead of LOCK_EX|LOCK_NB, ie: block */
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return flock( fd, LOCK_EX );
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}
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int lutil_unlockf ( int fd ) {
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return flock( fd, LOCK_UN );
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}
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#endif
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