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|
/*-------------------------------------------------------------------.
| Copyright 2001 Alexandre Duret-Lutz <duret_g@epita.fr> |
| |
| This program is free software; you can redistribute it and/or |
| modify it under the terms of the GNU General Public License as |
| published by the Free Software Foundation; either version 2 of the |
| License, or (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA |
`-------------------------------------------------------------------*/
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include <unistd.h>
#include <stdio.h>
#if HAVE_FCNTL_H
# include <fcntl.h>
#endif
#if HAVE_SYS_FILE_H
# include <sys/file.h>
#endif
/* These two files are for Windows (MinGW actually). */
#if HAVE_IO_H
# include <io.h>
#endif
#if HAVE_SYS_LOCKING_H
# include <sys/locking.h>
#endif
#include "filelock.h"
/* fcntl() locking is prefered because it works over NFS, otherwise
we fall back to flock(), or _locking() (this one is for Windows). */
int
file_lock (int fd, int exclusive)
{
#if HAVE_FCNTL && defined(F_SETLKW)
struct flock lock;
lock.l_type = exclusive ? F_WRLCK : F_RDLCK;
lock.l_whence = SEEK_SET;
lock.l_start = 0;
lock.l_len = 0; /* Lock the whole file. */
return fcntl (fd, F_SETLKW, &lock);
#else /* !(HAVE_FCNTL && defined(F_SETLKW)) */
# if HAVE_FLOCK
return flock (fd, exclusive ? LOCK_EX : LOCK_SH);
# else /* !HAVE_FLOCK */
# if HAVE__LOCKING
/* Lock the 10 next bytes. */
return _locking (fd, exclusive ? _LK_LOCK : _LK_RLCK, 10);
# else /* !HAVE__LOCKING */
/* FIXME: implement other kind of locking for system. */
return -1;
# endif /* !HAVE_LOCKING */
# endif /* !HAVE_FLOCK */
#endif /* !(HAVE_FCNTL && defined(F_SETLKW)) */
}
int
file_unlock (int fd)
{
#if HAVE_FCNTL && defined(F_SETLKW)
struct flock lock;
lock.l_type = F_UNLCK;
lock.l_whence = SEEK_SET;
lock.l_start = 0;
lock.l_len = 0; /* Unlock the whole file. */
return fcntl (fd, F_SETLKW, &lock);
#else /* !(HAVE_FCNTL && defined(F_SETLKW)) */
# if HAVE_FLOCK
return flock (fd, LOCK_UN);
# else /* !HAVE_FLOCK */
# if HAVE__LOCKING
/* Some version of MinGW used to spell _LK_UNLCK with an O. */
# ifndef _LK_UNLCK
# ifdef _LK_UNLOCK
# define _LK_UNLCK _LK_UNLOCK
# endif
# endif
/* Unlock the 10 next bytes. */
return _locking (fd, _LK_UNLCK, 10);
# else /* !HAVE__LOCKING */
/* FIXME: implement other kind of locking for system. */
return -1;
# endif /* !HAVE__LOCKING */
# endif /* !HAVE_FLOCK */
#endif /* !(HAVE_FCNTL && defined(F_SETLKW)) */
}
|
