4.3BSD - /usr/src/ucb/window/wwpty.c

   1: #ifndef lint
   2: static char sccsid[] = "@(#)wwpty.c	3.11 4/24/85";
   3: #endif
   4: 
   5: /*
   6:  * Copyright (c) 1983 Regents of the University of California,
   7:  * All rights reserved.  Redistribution permitted subject to
   8:  * the terms of the Berkeley Software License Agreement.
   9:  */
  10: 
  11: #include "ww.h"
  12: 
  13: /*
  14:  * To satisfy Chris, we allocate pty's backwards, and if
  15:  * there are more than the ptyp's (i.e. the ptyq's)
  16:  * on the machine, we don't use the p's.
  17:  */
  18: wwgetpty(w)
  19: register struct ww *w;
  20: {
  21:     register char c;
  22:     register int i;
  23:     int tty;
  24:     int on = 1;
  25:     char hasq = 0;
  26: #define PTY "/dev/XtyXX"
  27: #define _PT 5
  28: #define _PQRS   8
  29: #define _0_9    9
  30: 
  31:     (void) strcpy(w->ww_ttyname, PTY);
  32:     for (c = 's'; c >= 'p'; c--) {
  33:         w->ww_ttyname[_PT] = 'p';
  34:         w->ww_ttyname[_PQRS] = c;
  35:         w->ww_ttyname[_0_9] = '0';
  36:         if (access(w->ww_ttyname, 0) < 0)
  37:             continue;
  38:         if (c != 'p')
  39:             hasq = 1;
  40:         else if (hasq)
  41:             break;
  42:         for (i = 15; i >= 0; i--) {
  43:             w->ww_ttyname[_PT] = 'p';
  44:             w->ww_ttyname[_0_9] = "0123456789abcdef"[i];
  45:             if ((w->ww_pty = open(w->ww_ttyname, 2)) < 0)
  46:                 continue;
  47:             w->ww_ttyname[_PT] = 't';
  48:             if ((tty = open(w->ww_ttyname, 2)) < 0) {
  49:                 (void) close(w->ww_pty);
  50:                 continue;
  51:             }
  52:             (void) close(tty);
  53:             if (ioctl(w->ww_pty, (int)TIOCPKT, (char *)&on) < 0) {
  54:                 (void) close(w->ww_pty);
  55:                 continue;
  56:             }
  57:             return 0;
  58:         }
  59:     }
  60:     w->ww_pty = -1;
  61:     wwerrno = WWE_NOPTY;
  62:     return -1;
  63: }

Defined functions

Defined variables

Defined macros