ttycontrol.c

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/* ttycontrol.c - ttycontrol */

#include <xinu.h>

/*------------------------------------------------------------------------
 *  ttycontrol  -  Control a tty device by setting modes
 *------------------------------------------------------------------------
 */
devcall ttycontrol(
      struct dentry *devptr,    /* Entry in device switch table */
      int32  func,          /* Function to perform      */
      int32  arg1,          /* Argument 1 for request   */
      int32  arg2           /* Argument 2 for request   */
    )
{
    struct  ttycblk *typtr;     /* Pointer to tty control block */
    char    ch;         /* Character for lookahead  */

    typtr = &ttytab[devptr->dvminor];

    /* Process the request */

    switch ( func ) {

    case TC_NEXTC:
        wait(typtr->tyisem);
        ch = *typtr->tyitail;
        signal(typtr->tyisem);
        return (devcall)ch;

    case TC_MODER:
        typtr->tyimode = TY_IMRAW;
        return (devcall)OK;

    case TC_MODEC:
        typtr->tyimode = TY_IMCOOKED;
        return (devcall)OK;

    case TC_MODEK:
        typtr->tyimode = TY_IMCBREAK;
        return (devcall)OK;

    case TC_ICHARS:
        return(semcount(typtr->tyisem));

    case TC_ECHO:
        typtr->tyiecho = TRUE;
        return (devcall)OK;

    case TC_NOECHO:
        typtr->tyiecho = FALSE;
        return (devcall)OK;

    default:
        return (devcall)SYSERR;
    }
}