/* mount.c - mount, namlen */

#include 

/*------------------------------------------------------------------------
 *  mount  -  Add a prefix mapping to the name space
 *------------------------------------------------------------------------
 */
syscall mount(
          char          *prefix,        /* Prefix to add                */
          char          *replace,       /* Replacement string           */
          did32         device          /* Device ID to use             */
)
{
        intmask mask;                   /* Saved interrupt mask         */
        struct  nmentry *namptr;        /* Pointer to unused table entry*/
        int32   psiz, rsiz;             /* Sizes of prefix & replacement*/
        int32   i;                      /* Counter for copy loop        */

        mask = disable();

        psiz = namlen(prefix, NM_PRELEN);
        rsiz = namlen(replace, NM_REPLLEN);

        /* Check for table lverflow */

        if (nnames >= NNAMES) {
                kprintf("Namespace overflow\n");
                restore(mask);
                return SYSERR;
        }

        /* If arguments are invalid or table is full, return error */

        if ( (psiz == SYSERR) || (rsiz == SYSERR) || isbaddev(device) ) {
                restore(mask);
                return SYSERR;
        }

        /* Allocate a slot in the table */

        namptr = &nametab[nnames];      /* Next unused entry in table   */

        /* Copy prefix and replacement strings and record device ID */
        
        for (i=0; inprefix[i] = *prefix++;
        }

        for (i=0; inreplace[i] = *replace++;
        }

        namptr->ndevice = device;       /* Record the device ID         */

        nnames++;                       /* Increment number of names    */

        restore(mask);
        return OK;
}


/*------------------------------------------------------------------------
 *  namlen  -  Compute the length of a string stopping at maxlen
 *------------------------------------------------------------------------
 */
int32   namlen(
          char          *name,          /* Name to use                  */
          int32         maxlen          /* Maximum length (including a  */
                                        /*   NULLCH)                    */
)
{
        int32   i;                      /* Count of characters found    */

        /* Search until a null terminator or length reaches max */

        for (i=0; i < maxlen; i++) {
                if (*name++ == NULLCH) {
                        return i+1;     /* Include NULLCH in length */
                }
        }
        return SYSERR;
}