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

   1: #ifndef lint
   2: static char sccsid[] = "@(#)wwiomux.c	3.15 9/19/85";
   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: #include <sys/time.h>
  13: #include <sys/types.h>
  14: 
  15: /*
  16:  * Multiple window output handler.
  17:  * The idea is to copy window outputs to the terminal, via the
  18:  * display package.  We try to give the top most window highest
  19:  * priority.  The only return condition is when there is keyboard
  20:  * input, which is serviced asynchronously by wwrint().
  21:  * When there's nothing to do, we sleep in a select().
  22:  * This can be done better with interrupt driven io.  But that's
  23:  * not supported on ptys, yet.
  24:  * The history of this routine is interesting.
  25:  */
  26: wwiomux()
  27: {
  28:     register struct ww *w;
  29:     fd_set imask;
  30:     register n;
  31:     register char *p;
  32:     char c;
  33:     static struct timeval tv = { 0, 0 };
  34:     char noblock;
  35: 
  36: loop:
  37:     if (wwinterrupt())
  38:         return;
  39: 
  40:     FD_ZERO(&imask);
  41:     noblock = 0;
  42:     for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
  43:         if (w->ww_pty < 0)
  44:             continue;
  45:         if (w->ww_obq < w->ww_obe)
  46:             FD_SET(w->ww_pty, &imask);
  47:         if (w->ww_obq > w->ww_obp && !w->ww_stopped)
  48:             noblock = 1;
  49:     }
  50: 
  51:     if (!noblock) {
  52:         if (wwcurwin != 0)
  53:             wwcurtowin(wwcurwin);
  54:         wwupdate();
  55:         wwflush();
  56:         if (setjmp(wwjmpbuf))
  57:             return;
  58:         wwsetjmp = 1;
  59:         if (wwinterrupt()) {
  60:             wwsetjmp = 0;
  61:             return;
  62:         }
  63:     }
  64:     wwnselect++;
  65:     n = select(wwdtablesize, &imask, (fd_set *)0, (fd_set *)0,
  66:         noblock ? &tv : (struct timeval *)0);
  67:     wwsetjmp = 0;
  68: 
  69:     if (n < 0)
  70:         wwnselecte++;
  71:     else if (n == 0)
  72:         wwnselectz++;
  73:     else
  74:         for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
  75:             if (w->ww_pty < 0 || !FD_ISSET(w->ww_pty, &imask))
  76:                 continue;
  77:             wwnwread++;
  78:             p = w->ww_obq;
  79:             if (w->ww_ispty) {
  80:                 if (p == w->ww_ob) {
  81:                     w->ww_obp++;
  82:                     w->ww_obq++;
  83:                 } else
  84:                     p--;
  85:                 c = *p;
  86:             }
  87:             n = read(w->ww_pty, p, w->ww_obe - p);
  88:             if (n < 0) {
  89:                 wwnwreade++;
  90:                 (void) close(w->ww_pty);
  91:                 w->ww_pty = -1;
  92:             } else if (n == 0) {
  93:                 wwnwreadz++;
  94:                 (void) close(w->ww_pty);
  95:                 w->ww_pty = -1;
  96:             } else if (!w->ww_ispty) {
  97:                 wwnwreadd++;
  98:                 wwnwreadc += n;
  99:                 w->ww_obq += n;
 100:             } else if (*p == TIOCPKT_DATA) {
 101:                 n--;
 102:                 wwnwreadd++;
 103:                 wwnwreadc += n;
 104:                 w->ww_obq += n;
 105:             } else {
 106:                 wwnwreadp++;
 107:                 if (*p & TIOCPKT_STOP)
 108:                     w->ww_stopped = 1;
 109:                 if (*p & TIOCPKT_START)
 110:                     w->ww_stopped = 0;
 111:                 if (*p & TIOCPKT_FLUSHWRITE) {
 112:                     w->ww_stopped = 0;
 113:                     w->ww_obq = w->ww_obp = w->ww_ob;
 114:                 }
 115:             }
 116:             if (w->ww_ispty)
 117:                 *p = c;
 118:         }
 119:     for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw)
 120:         if (w->ww_pty >= 0 && w->ww_obq > w->ww_obp && !w->ww_stopped) {
 121:             n = wwwrite(w, w->ww_obp, w->ww_obq - w->ww_obp);
 122:             if ((w->ww_obp += n) == w->ww_obq)
 123:                 w->ww_obq = w->ww_obp = w->ww_ob;
 124:             if (wwinterrupt())
 125:                 return;
 126:             break;
 127:         }
 128:     goto loop;
 129: }

Defined functions

Defined variables