usr.bin/window/wwiomux.c

   1 /*
   2  * Copyright (c) 1983, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Edward Wang at The University of California, Berkeley.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)wwiomux.c        8.1 (Berkeley) 6/6/93
  37  * $FreeBSD: src/usr.bin/window/wwiomux.c,v 1.1.1.1.14.1 2001/05/17 09:45:01 obrien Exp $
  38  * $DragonFly: src/usr.bin/window/wwiomux.c,v 1.2 2003/06/17 04:29:34 dillon Exp $
  39  */
  40
  41 #include "ww.h"
  42 #include <sys/time.h>
  43 #include <sys/types.h>
  44 #if !defined(OLD_TTY) && !defined(TIOCPKT_DATA)
  45 #include <sys/ioctl.h>
  46 #endif
  47 #include <fcntl.h>
  48
  49 /*
  50  * Multiple window output handler.
  51  * The idea is to copy window outputs to the terminal, via the
  52  * display package.  We try to give wwcurwin highest priority.
  53  * The only return conditions are when there is keyboard input
  54  * and when a child process dies, which are serviced by signal
  55  * catchers (wwrint() and wwchild()).
  56  * When there's nothing to do, we sleep in a select().
  57  * This can be done better with interrupt driven io.  But that's
  58  * not supported on ptys, yet.
  59  * The history of this routine is interesting.
  60  */
  61 wwiomux()
  62 {
  63         register struct ww *w;
  64         fd_set imask;
  65         register n;
  66         register char *p;
  67         char c;
  68         struct timeval tv;
  69         char noblock = 0;
  70
  71         for (;;) {
  72                 if (wwinterrupt()) {
  73                         wwclrintr();
  74                         return;
  75                 }
  76
  77                 FD_ZERO(&imask);
  78                 n = -1;
  79                 for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
  80                         if (w->ww_pty < 0)
  81                                 continue;
  82                         if (w->ww_obq < w->ww_obe) {
  83                                 if (w->ww_pty > n)
  84                                         n = w->ww_pty;
  85                                 FD_SET(w->ww_pty, &imask);
  86                         }
  87                         if (w->ww_obq > w->ww_obp && !w->ww_stopped)
  88                                 noblock = 1;
  89                 }
  90
  91                 if (!noblock) {
  92                         if (wwcurwin != 0)
  93                                 wwcurtowin(wwcurwin);
  94                         wwupdate();
  95                         wwflush();
  96                         (void) setjmp(wwjmpbuf);
  97                         wwsetjmp = 1;
  98                         if (wwinterrupt()) {
  99                                 wwsetjmp = 0;
 100                                 wwclrintr();
 101                                 return;
 102                         }
 103                         /*
 104                          * Defensive code.  If somebody else (for example,
 105                          * wall) clears the ASYNC flag on us, we will block
 106                          * forever.  So we need a finite timeout and set
 107                          * the flag again.  Anything more clever will probably
 108                          * need even more system calls.  (This is a bug
 109                          * in the kernel.)
 110                          * I don't like this one bit.
 111                          */
 112                         (void) fcntl(0, F_SETFL, wwnewtty.ww_fflags);
 113                         tv.tv_sec = 30;
 114                         tv.tv_usec = 0;
 115                 } else {
 116                         tv.tv_sec = 0;
 117                         tv.tv_usec = 10000;
 118                 }
 119                 wwnselect++;
 120                 n = select(n + 1, &imask, (fd_set *)0, (fd_set *)0, &tv);
 121                 wwsetjmp = 0;
 122                 noblock = 0;
 123
 124                 if (n < 0)
 125                         wwnselecte++;
 126                 else if (n == 0)
 127                         wwnselectz++;
 128                 else
 129                         for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
 130                                 if (w->ww_pty < 0 ||
 131                                     !FD_ISSET(w->ww_pty, &imask))
 132                                         continue;
 133                                 wwnwread++;
 134                                 p = w->ww_obq;
 135                                 if (w->ww_ispty) {
 136                                         if (p == w->ww_ob) {
 137                                                 w->ww_obp++;
 138                                                 w->ww_obq++;
 139                                         } else
 140                                                 p--;
 141                                         c = *p;
 142                                 }
 143                                 n = read(w->ww_pty, p, w->ww_obe - p);
 144                                 if (n < 0) {
 145                                         wwnwreade++;
 146                                         (void) close(w->ww_pty);
 147                                         w->ww_pty = -1;
 148                                 } else if (n == 0) {
 149                                         wwnwreadz++;
 150                                         (void) close(w->ww_pty);
 151                                         w->ww_pty = -1;
 152                                 } else if (!w->ww_ispty) {
 153                                         wwnwreadd++;
 154                                         wwnwreadc += n;
 155                                         w->ww_obq += n;
 156                                 } else if (*p == TIOCPKT_DATA) {
 157                                         n--;
 158                                         wwnwreadd++;
 159                                         wwnwreadc += n;
 160                                         w->ww_obq += n;
 161                                 } else {
 162                                         wwnwreadp++;
 163                                         if (*p & TIOCPKT_STOP)
 164                                                 w->ww_stopped = 1;
 165                                         if (*p & TIOCPKT_START)
 166                                                 w->ww_stopped = 0;
 167                                         if (*p & TIOCPKT_FLUSHWRITE) {
 168                                                 w->ww_stopped = 0;
 169                                                 w->ww_obq = w->ww_obp =
 170                                                         w->ww_ob;
 171                                         }
 172                                 }
 173                                 if (w->ww_ispty)
 174                                         *p = c;
 175                         }
 176                 /*
 177                  * Try the current window first, if there is output
 178                  * then process it and go back to the top to try again.
 179                  * This can lead to starvation of the other windows,
 180                  * but presumably that what we want.
 181                  * Update will eventually happen when output from wwcurwin
 182                  * dies down.
 183                  */
 184                 if ((w = wwcurwin) != 0 && w->ww_pty >= 0 &&
 185                     w->ww_obq > w->ww_obp && !w->ww_stopped) {
 186                         n = wwwrite(w, w->ww_obp, w->ww_obq - w->ww_obp);
 187                         if ((w->ww_obp += n) == w->ww_obq)
 188                                 w->ww_obq = w->ww_obp = w->ww_ob;
 189                         noblock = 1;
 190                         continue;
 191                 }
 192                 for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw)
 193                         if (w->ww_pty >= 0 && w->ww_obq > w->ww_obp &&
 194                             !w->ww_stopped) {
 195                                 n = wwwrite(w, w->ww_obp,
 196                                         w->ww_obq - w->ww_obp);
 197                                 if ((w->ww_obp += n) == w->ww_obq)
 198                                         w->ww_obq = w->ww_obp = w->ww_ob;
 199                                 if (wwinterrupt())
 200                                         break;
 201                         }
 202         }
 203 }