/* lflcontrol.c - lflcontrol */

#include 

/*------------------------------------------------------------------------
 * lflcontrol  -  Provide control functions for a local file pseudo-device
 *------------------------------------------------------------------------
 */
devcall lflcontrol (
         struct dentry  *devptr,        /* Entry in device switch table */
         int32  func,                   /* A control function           */
         int32  arg1,                   /* Argument #1                  */
         int32  arg2                    /* Argument #2                  */
        )
{
        struct  lflcblk *lfptr;         /* Ptr to open file table entry */
        int32   retval;                 /* Return value from func. call */

        /* Obtain exclusive use of the file */

        lfptr = &lfltab[devptr->dvminor];
        wait(lfptr->lfmutex);

        /* If file is not open, return an error */

        if (lfptr->lfstate != LF_USED) {
                signal(lfptr->lfmutex);
                return SYSERR;
        }

        switch (func) {

        /* Truncate a file */

        case LF_CTL_TRUNC:
                wait(Lf_data.lf_mutex);
                retval = lftruncate(lfptr);
                signal(Lf_data.lf_mutex);
                signal(lfptr->lfmutex);
                return retval;  

        default:
                kprintf("lfcontrol: function %d not valid\n", func);
                signal(lfptr->lfmutex);
                return SYSERR;
        }
}