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 1.3 2008/05/19 10:19:49 corecode Exp $
  39  */
  40
  41 #include "ww.h"
  42 #include <sys/time.h>
  43 #include <sys/types.h>
  44 #include <sys/select.h>
  45 #if !defined(OLD_TTY) && !defined(TIOCPKT_DATA)
  46 #include <sys/ioctl.h>
  47 #endif
  48 #include <fcntl.h>
  49
  50 /*
  51  * Multiple window output handler.
  52  * The idea is to copy window outputs to the terminal, via the
  53  * display package.  We try to give wwcurwin highest priority.
  54  * The only return conditions are when there is keyboard input
  55  * and when a child process dies, which are serviced by signal
  56  * catchers (wwrint() and wwchild()).
  57  * When there's nothing to do, we sleep in a select().
  58  * This can be done better with interrupt driven io.  But that's
  59  * not supported on ptys, yet.
  60  * The history of this routine is interesting.
  61  */
  62 wwiomux()
  63 {
  64         register struct ww *w;
  65         fd_set imask;
  66         register n;
  67         register char *p;
  68         char c;
  69         struct timeval tv;
  70         char noblock = 0;
  71
  72         for (;;) {
  73                 if (wwinterrupt()) {
  74                         wwclrintr();
  75                         return;
  76                 }
  77
  78                 FD_ZERO(&imask);
  79                 n = -1;
  80                 for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
  81                         if (w->ww_pty < 0)
  82                                 continue;
  83                         if (w->ww_obq < w->ww_obe) {
  84                                 if (w->ww_pty > n)
  85                                         n = w->ww_pty;
  86                                 FD_SET(w->ww_pty, &imask);
  87                         }
  88                         if (w->ww_obq > w->ww_obp && !w->ww_stopped)
  89                                 noblock = 1;
  90                 }
  91
  92                 if (!noblock) {
  93                         if (wwcurwin != 0)
  94                                 wwcurtowin(wwcurwin);
  95                         wwupdate();
  96                         wwflush();
  97                         (void) setjmp(wwjmpbuf);
  98                         wwsetjmp = 1;
  99                         if (wwinterrupt()) {
 100                                 wwsetjmp = 0;
 101                                 wwclrintr();
 102                                 return;
 103                         }
 104                         /*
 105                          * Defensive code.  If somebody else (for example,
 106                          * wall) clears the ASYNC flag on us, we will block
 107                          * forever.  So we need a finite timeout and set
 108                          * the flag again.  Anything more clever will probably
 109                          * need even more system calls.  (This is a bug
 110                          * in the kernel.)
 111                          * I don't like this one bit.
 112                          */
 113                         (void) fcntl(0, F_SETFL, wwnewtty.ww_fflags);
 114                         tv.tv_sec = 30;
 115                         tv.tv_usec = 0;
 116                 } else {
 117                         tv.tv_sec = 0;
 118                         tv.tv_usec = 10000;
 119                 }
 120                 wwnselect++;
 121                 n = select(n + 1, &imask, NULL, NULL, &tv);
 122                 wwsetjmp = 0;
 123                 noblock = 0;
 124
 125                 if (n < 0)
 126                         wwnselecte++;
 127                 else if (n == 0)
 128                         wwnselectz++;
 129                 else
 130                         for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
 131                                 if (w->ww_pty < 0 ||
 132                                     !FD_ISSET(w->ww_pty, &imask))
 133                                         continue;
 134                                 wwnwread++;
 135                                 p = w->ww_obq;
 136                                 if (w->ww_ispty) {
 137                                         if (p == w->ww_ob) {
 138                                                 w->ww_obp++;
 139                                                 w->ww_obq++;
 140                                         } else
 141                                                 p--;
 142                                         c = *p;
 143                                 }
 144                                 n = read(w->ww_pty, p, w->ww_obe - p);
 145                                 if (n < 0) {
 146                                         wwnwreade++;
 147                                         (void) close(w->ww_pty);
 148                                         w->ww_pty = -1;
 149                                 } else if (n == 0) {
 150                                         wwnwreadz++;
 151                                         (void) close(w->ww_pty);
 152                                         w->ww_pty = -1;
 153                                 } else if (!w->ww_ispty) {
 154                                         wwnwreadd++;
 155                                         wwnwreadc += n;
 156                                         w->ww_obq += n;
 157                                 } else if (*p == TIOCPKT_DATA) {
 158                                         n--;
 159                                         wwnwreadd++;
 160                                         wwnwreadc += n;
 161                                         w->ww_obq += n;
 162                                 } else {
 163                                         wwnwreadp++;
 164                                         if (*p & TIOCPKT_STOP)
 165                                                 w->ww_stopped = 1;
 166                                         if (*p & TIOCPKT_START)
 167                                                 w->ww_stopped = 0;
 168                                         if (*p & TIOCPKT_FLUSHWRITE) {
 169                                                 w->ww_stopped = 0;
 170                                                 w->ww_obq = w->ww_obp =
 171                                                         w->ww_ob;
 172                                         }
 173                                 }
 174                                 if (w->ww_ispty)
 175                                         *p = c;
 176                         }
 177                 /*
 178                  * Try the current window first, if there is output
 179                  * then process it and go back to the top to try again.
 180                  * This can lead to starvation of the other windows,
 181                  * but presumably that what we want.
 182                  * Update will eventually happen when output from wwcurwin
 183                  * dies down.
 184                  */
 185                 if ((w = wwcurwin) != 0 && w->ww_pty >= 0 &&
 186                     w->ww_obq > w->ww_obp && !w->ww_stopped) {
 187                         n = wwwrite(w, w->ww_obp, w->ww_obq - w->ww_obp);
 188                         if ((w->ww_obp += n) == w->ww_obq)
 189                                 w->ww_obq = w->ww_obp = w->ww_ob;
 190                         noblock = 1;
 191                         continue;
 192                 }
 193                 for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw)
 194                         if (w->ww_pty >= 0 && w->ww_obq > w->ww_obp &&
 195                             !w->ww_stopped) {
 196                                 n = wwwrite(w, w->ww_obp,
 197                                         w->ww_obq - w->ww_obp);
 198                                 if ((w->ww_obp += n) == w->ww_obq)
 199                                         w->ww_obq = w->ww_obp = w->ww_ob;
 200                                 if (wwinterrupt())
 201                                         break;
 202                         }
 203         }
 204 }