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1.1 deraadt 1: /* $NetBSD: wwiomux.c,v 1.3 1995/09/28 10:35:37 tls Exp $ */
2:
3: /*
4: * Copyright (c) 1983, 1993
5: * The Regents of the University of California. All rights reserved.
6: *
7: * This code is derived from software contributed to Berkeley by
8: * Edward Wang at The University of California, Berkeley.
9: *
10: * Redistribution and use in source and binary forms, with or without
11: * modification, are permitted provided that the following conditions
12: * are met:
13: * 1. Redistributions of source code must retain the above copyright
14: * notice, this list of conditions and the following disclaimer.
15: * 2. Redistributions in binary form must reproduce the above copyright
16: * notice, this list of conditions and the following disclaimer in the
17: * documentation and/or other materials provided with the distribution.
18: * 3. All advertising materials mentioning features or use of this software
19: * must display the following acknowledgement:
20: * This product includes software developed by the University of
21: * California, Berkeley and its contributors.
22: * 4. Neither the name of the University nor the names of its contributors
23: * may be used to endorse or promote products derived from this software
24: * without specific prior written permission.
25: *
26: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36: * SUCH DAMAGE.
37: */
38:
39: #ifndef lint
40: #if 0
41: static char sccsid[] = "@(#)wwiomux.c 8.1 (Berkeley) 6/6/93";
42: #else
43: static char rcsid[] = "$NetBSD: wwiomux.c,v 1.3 1995/09/28 10:35:37 tls Exp $";
44: #endif
45: #endif /* not lint */
46:
47: #include "ww.h"
48: #include <sys/time.h>
49: #include <sys/types.h>
50: #if !defined(OLD_TTY) && !defined(TIOCPKT_DATA)
51: #include <sys/ioctl.h>
52: #endif
53: #include <fcntl.h>
54:
55: /*
56: * Multiple window output handler.
57: * The idea is to copy window outputs to the terminal, via the
58: * display package. We try to give wwcurwin highest priority.
59: * The only return conditions are when there is keyboard input
60: * and when a child process dies, which are serviced by signal
61: * catchers (wwrint() and wwchild()).
62: * When there's nothing to do, we sleep in a select().
63: * This can be done better with interrupt driven io. But that's
64: * not supported on ptys, yet.
65: * The history of this routine is interesting.
66: */
67: wwiomux()
68: {
69: register struct ww *w;
70: fd_set imask;
71: register n;
72: register char *p;
73: char c;
74: struct timeval tv;
75: char noblock = 0;
76:
77: for (;;) {
78: if (wwinterrupt()) {
79: wwclrintr();
80: return;
81: }
82:
83: FD_ZERO(&imask);
84: n = -1;
85: for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
86: if (w->ww_pty < 0)
87: continue;
88: if (w->ww_obq < w->ww_obe) {
89: if (w->ww_pty > n)
90: n = w->ww_pty;
91: FD_SET(w->ww_pty, &imask);
92: }
93: if (w->ww_obq > w->ww_obp && !w->ww_stopped)
94: noblock = 1;
95: }
96:
97: if (!noblock) {
98: if (wwcurwin != 0)
99: wwcurtowin(wwcurwin);
100: wwupdate();
101: wwflush();
102: (void) setjmp(wwjmpbuf);
103: wwsetjmp = 1;
104: if (wwinterrupt()) {
105: wwsetjmp = 0;
106: wwclrintr();
107: return;
108: }
109: /*
110: * Defensive code. If somebody else (for example,
111: * wall) clears the ASYNC flag on us, we will block
112: * forever. So we need a finite timeout and set
113: * the flag again. Anything more clever will probably
114: * need even more system calls. (This is a bug
115: * in the kernel.)
116: * I don't like this one bit.
117: */
118: (void) fcntl(0, F_SETFL, wwnewtty.ww_fflags);
119: tv.tv_sec = 30;
120: tv.tv_usec = 0;
121: } else {
122: tv.tv_sec = 0;
123: tv.tv_usec = 10000;
124: }
125: wwnselect++;
126: n = select(n + 1, &imask, (fd_set *)0, (fd_set *)0, &tv);
127: wwsetjmp = 0;
128: noblock = 0;
129:
130: if (n < 0)
131: wwnselecte++;
132: else if (n == 0)
133: wwnselectz++;
134: else
135: for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
136: if (w->ww_pty < 0 ||
137: !FD_ISSET(w->ww_pty, &imask))
138: continue;
139: wwnwread++;
140: p = w->ww_obq;
141: if (w->ww_ispty) {
142: if (p == w->ww_ob) {
143: w->ww_obp++;
144: w->ww_obq++;
145: } else
146: p--;
147: c = *p;
148: }
149: n = read(w->ww_pty, p, w->ww_obe - p);
150: if (n < 0) {
151: wwnwreade++;
152: (void) close(w->ww_pty);
153: w->ww_pty = -1;
154: } else if (n == 0) {
155: wwnwreadz++;
156: (void) close(w->ww_pty);
157: w->ww_pty = -1;
158: } else if (!w->ww_ispty) {
159: wwnwreadd++;
160: wwnwreadc += n;
161: w->ww_obq += n;
162: } else if (*p == TIOCPKT_DATA) {
163: n--;
164: wwnwreadd++;
165: wwnwreadc += n;
166: w->ww_obq += n;
167: } else {
168: wwnwreadp++;
169: if (*p & TIOCPKT_STOP)
170: w->ww_stopped = 1;
171: if (*p & TIOCPKT_START)
172: w->ww_stopped = 0;
173: if (*p & TIOCPKT_FLUSHWRITE) {
174: w->ww_stopped = 0;
175: w->ww_obq = w->ww_obp =
176: w->ww_ob;
177: }
178: }
179: if (w->ww_ispty)
180: *p = c;
181: }
182: /*
183: * Try the current window first, if there is output
184: * then process it and go back to the top to try again.
185: * This can lead to starvation of the other windows,
186: * but presumably that what we want.
187: * Update will eventually happen when output from wwcurwin
188: * dies down.
189: */
190: if ((w = wwcurwin) != 0 && w->ww_pty >= 0 &&
191: w->ww_obq > w->ww_obp && !w->ww_stopped) {
192: n = wwwrite(w, w->ww_obp, w->ww_obq - w->ww_obp);
193: if ((w->ww_obp += n) == w->ww_obq)
194: w->ww_obq = w->ww_obp = w->ww_ob;
195: noblock = 1;
196: continue;
197: }
198: for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw)
199: if (w->ww_pty >= 0 && w->ww_obq > w->ww_obp &&
200: !w->ww_stopped) {
201: n = wwwrite(w, w->ww_obp,
202: w->ww_obq - w->ww_obp);
203: if ((w->ww_obp += n) == w->ww_obq)
204: w->ww_obq = w->ww_obp = w->ww_ob;
205: if (wwinterrupt())
206: break;
207: }
208: }
209: }