usr/src/usr.bin/window/wwpty.c

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that this notice is preserved and that due credit is given
 * to the University of California at Berkeley. The name of the University
 * may not be used to endorse or promote products derived from this
 * software without specific prior written permission. This software
 * is provided ``as is'' without express or implied warranty.
 */

#ifndef lint
static char sccsid[] = "@(#)wwpty.c     3.14 (Berkeley) %G%";
#endif /* not lint */

#include "ww.h"

wwgetpty(w)
register struct ww *w;
{
        register char c, *p;
        int tty;
        int on = 1;
#define PTY "/dev/XtyXX"
#define _PT     5
#define _PQRS   8
#define _0_9    9

        (void) strcpy(w->ww_ttyname, PTY);
        for (c = 'p'; c <= 'u'; c++) {
                w->ww_ttyname[_PT] = 'p';
                w->ww_ttyname[_PQRS] = c;
                w->ww_ttyname[_0_9] = '0';
                if (access(w->ww_ttyname, 0) < 0)
                        break;
                for (p = "0123456789abcdef"; *p; p++) {
                        w->ww_ttyname[_PT] = 'p';
                        w->ww_ttyname[_0_9] = *p;
                        if ((w->ww_pty = open(w->ww_ttyname, 2)) < 0)
                                continue;
                        w->ww_ttyname[_PT] = 't';
                        if ((tty = open(w->ww_ttyname, 2)) < 0) {
                                (void) close(w->ww_pty);
                                continue;
                        }
                        (void) close(tty);
                        if (ioctl(w->ww_pty, TIOCPKT, (char *)&on) < 0) {
                                (void) close(w->ww_pty);
                                continue;
                        }
                        return 0;
                }
        }
        w->ww_pty = -1;
        wwerrno = WWE_NOPTY;
        return -1;
}