/*
*******************************************************************************
*  Copyright (c) 1996 Martin Poole                            *
*******************************************************************************
**
** WARNING !!  WARNING !! WARNING !! WARNING !! WARNING !! WARNING !!
**
** Any changes to be made to this file should first be checked with
** mplib1 source control for library integrity.
**
** mplib1 source control can be reached at  mplib1@quatermass.co.uk
** 
*
*  $Source: /home/cvs/cvsroot/onelan/onelan/src/mplib1/libsrc/lock_file.c,v $
*  $Author: mpoole $
*  $Date: 2002/10/07 09:37:39 $
*  $Revision: 1.2 $
*
*******************************************************************************
*
* Change History
*
* $Log: lock_file.c,v $
* Revision 1.2  2002/10/07 09:37:39  mpoole
* Initial checkin of mplib1-3.1.0
*
* Revision 1.1  2002/10/07 09:36:57  mpoole
* Initial checkin of mplib1-3.1.0
*
*
*******************************************************************************
*/

#ident "$Header: /home/cvs/cvsroot/onelan/onelan/src/mplib1/libsrc/lock_file.c,v 1.2 2002/10/07 09:37:39 mpoole Exp $"

/* ------------------------------------------------------------------
    Include files
   ------------------------------------------------------------------ */

#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <string.h>

#include <mplib1/mplib1_config.h>
#include <mplib1/pid_check.h>
#include <mplib1/fprintfile.h>
#include <mplib1/lock_file.h>

/* ------------------------------------------------------------------
    defines
   ------------------------------------------------------------------ */

/* ------------------------------------------------------------------
    Code starts here
   ------------------------------------------------------------------ */

int
lock_reg( int fd, int cmd, int type, off_t offset, int whence, off_t len )
{
    struct flock lock;

    lock.l_type = type;
    lock.l_start = offset;
    lock.l_whence = whence;
    lock.l_len = len;

    return( fcntl( fd, cmd, &lock ) );
}

int
lock_file( const char *filename )
{
    int fd,val;
    int rv = 0;
    char buf[PID_STR_LEN];

    if ( (fd = open( filename, O_WRONLY | O_CREAT, 0644 )) >= 0)
    {
	gen_pid_str( buf, getpid() );
	if (   (write_lock( fd, 0, SEEK_SET, 0) >= 0)
	    && (ftruncate(fd, 0) >= 0)
	    && (write(fd,buf,strlen(buf)) == strlen(buf))
	    && ( (val = fcntl(fd, F_GETFD, 0)) >= 0)
	   )
	{
	    val |= FD_CLOEXEC;
	    if (fcntl(fd, F_SETFD, val) >=0 )
		rv=1;
	}
	if (rv==0)
	    close(fd);
    }
    return(rv);
}


/* -- End of File -- */