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598b7473fe
the lock is acquired. Add comments to that effect. Remove unnecessary busy loops from slapd/lock.c and slurpd/lock.c.
102 lines
2.1 KiB
C
102 lines
2.1 KiB
C
/*
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* Copyright 1998,1999 The OpenLDAP Foundation, Redwood City, California, USA
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted only
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* as authorized by the OpenLDAP Public License. A copy of this
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* license is available at http://www.OpenLDAP.org/license.html or
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* in file LICENSE in the top-level directory of the distribution.
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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 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) && 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) && HAVE_FLOCK
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# if 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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#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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