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BSD 4_3_Net_2 release
[unix-history] / usr / src / usr.bin / window / wwiomux.c
/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Edward Wang at The University of California, Berkeley.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char sccsid[] = "@(#)wwiomux.c 3.26 (Berkeley) 8/12/90";
#endif /* not lint */
#include "ww.h"
#include <sys/time.h>
#include <sys/types.h>
#if !defined(OLD_TTY) && !defined(TIOCPKT_DATA)
#include <sys/ioctl.h>
#endif
#include <fcntl.h>
/*
* Multiple window output handler.
* The idea is to copy window outputs to the terminal, via the
* display package. We try to give wwcurwin highest priority.
* The only return conditions are when there is keyboard input
* and when a child process dies, which are serviced by signal
* catchers (wwrint() and wwchild()).
* When there's nothing to do, we sleep in a select().
* This can be done better with interrupt driven io. But that's
* not supported on ptys, yet.
* The history of this routine is interesting.
*/
wwiomux()
{
register struct ww *w;
fd_set imask;
register n;
register char *p;
char c;
struct timeval tv;
char noblock = 0;
for (;;) {
if (wwinterrupt()) {
wwclrintr();
return;
}
FD_ZERO(&imask);
for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
if (w->ww_pty < 0)
continue;
if (w->ww_obq < w->ww_obe)
FD_SET(w->ww_pty, &imask);
if (w->ww_obq > w->ww_obp && !w->ww_stopped)
noblock = 1;
}
if (!noblock) {
if (wwcurwin != 0)
wwcurtowin(wwcurwin);
wwupdate();
wwflush();
(void) setjmp(wwjmpbuf);
wwsetjmp = 1;
if (wwinterrupt()) {
wwsetjmp = 0;
wwclrintr();
return;
}
/*
* Defensive code. If somebody else (for example,
* wall) clears the ASYNC flag on us, we will block
* forever. So we need a finite timeout and set
* the flag again. Anything more clever will probably
* need even more system calls. (This is a bug
* in the kernel.)
* I don't like this one bit.
*/
(void) fcntl(0, F_SETFL, wwnewtty.ww_fflags);
tv.tv_sec = 30;
tv.tv_usec = 0;
} else {
tv.tv_sec = 0;
tv.tv_usec = 10000;
}
wwnselect++;
n = select(wwdtablesize, &imask, (fd_set *)0, (fd_set *)0, &tv);
wwsetjmp = 0;
noblock = 0;
if (n < 0)
wwnselecte++;
else if (n == 0)
wwnselectz++;
else
for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
if (w->ww_pty < 0 ||
!FD_ISSET(w->ww_pty, &imask))
continue;
wwnwread++;
p = w->ww_obq;
if (w->ww_ispty) {
if (p == w->ww_ob) {
w->ww_obp++;
w->ww_obq++;
} else
p--;
c = *p;
}
n = read(w->ww_pty, p, w->ww_obe - p);
if (n < 0) {
wwnwreade++;
(void) close(w->ww_pty);
w->ww_pty = -1;
} else if (n == 0) {
wwnwreadz++;
(void) close(w->ww_pty);
w->ww_pty = -1;
} else if (!w->ww_ispty) {
wwnwreadd++;
wwnwreadc += n;
w->ww_obq += n;
} else if (*p == TIOCPKT_DATA) {
n--;
wwnwreadd++;
wwnwreadc += n;
w->ww_obq += n;
} else {
wwnwreadp++;
if (*p & TIOCPKT_STOP)
w->ww_stopped = 1;
if (*p & TIOCPKT_START)
w->ww_stopped = 0;
if (*p & TIOCPKT_FLUSHWRITE) {
w->ww_stopped = 0;
w->ww_obq = w->ww_obp =
w->ww_ob;
}
}
if (w->ww_ispty)
*p = c;
}
/*
* Try the current window first, if there is output
* then process it and go back to the top to try again.
* This can lead to starvation of the other windows,
* but presumably that what we want.
* Update will eventually happen when output from wwcurwin
* dies down.
*/
if ((w = wwcurwin) != 0 && w->ww_pty >= 0 &&
w->ww_obq > w->ww_obp && !w->ww_stopped) {
n = wwwrite(w, w->ww_obp, w->ww_obq - w->ww_obp);
if ((w->ww_obp += n) == w->ww_obq)
w->ww_obq = w->ww_obp = w->ww_ob;
noblock = 1;
continue;
}
for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw)
if (w->ww_pty >= 0 && w->ww_obq > w->ww_obp &&
!w->ww_stopped) {
n = wwwrite(w, w->ww_obp,
w->ww_obq - w->ww_obp);
if ((w->ww_obp += n) == w->ww_obq)
w->ww_obq = w->ww_obp = w->ww_ob;
if (wwinterrupt())
break;
}
}
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.