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1.1 root 1: /*
2: * Copyright (c) 1983 Regents of the University of California.
3: * 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 are permitted provided
9: * that: (1) source distributions retain this entire copyright notice and
10: * comment, and (2) distributions including binaries display the following
11: * acknowledgement: ``This product includes software developed by the
12: * University of California, Berkeley and its contributors'' in the
13: * documentation or other materials provided with the distribution and in
14: * all advertising materials mentioning features or use of this software.
15: * Neither the name of the University nor the names of its contributors may
16: * be used to endorse or promote products derived from this software without
17: * specific prior written permission.
18: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
19: * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
20: * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21: */
22:
23: #ifndef lint
24: static char sccsid[] = "@(#)wwiomux.c 3.25 (Berkeley) 6/6/90";
25: #endif /* not lint */
26:
27: #include "ww.h"
28: #include <sys/time.h>
29: #include <sys/types.h>
30: #ifdef POSIX_TTY
31: #include <sys/ioctl.h>
32: #endif
33: #include <fcntl.h>
34:
35: /*
36: * Multiple window output handler.
37: * The idea is to copy window outputs to the terminal, via the
38: * display package. We try to give wwcurwin highest priority.
39: * The only return conditions are when there is keyboard input
40: * and when a child process dies, which are serviced by signal
41: * catchers (wwrint() and wwchild()).
42: * When there's nothing to do, we sleep in a select().
43: * This can be done better with interrupt driven io. But that's
44: * not supported on ptys, yet.
45: * The history of this routine is interesting.
46: */
47: wwiomux()
48: {
49: register struct ww *w;
50: fd_set imask;
51: register n;
52: register char *p;
53: char c;
54: struct timeval tv;
55: char noblock = 0;
56:
57: for (;;) {
58: if (wwinterrupt()) {
59: wwclrintr();
60: return;
61: }
62:
63: FD_ZERO(&imask);
64: for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
65: if (w->ww_pty < 0)
66: continue;
67: if (w->ww_obq < w->ww_obe)
68: FD_SET(w->ww_pty, &imask);
69: if (w->ww_obq > w->ww_obp && !w->ww_stopped)
70: noblock = 1;
71: }
72:
73: if (!noblock) {
74: if (wwcurwin != 0)
75: wwcurtowin(wwcurwin);
76: wwupdate();
77: wwflush();
78: (void) setjmp(wwjmpbuf);
79: wwsetjmp = 1;
80: if (wwinterrupt()) {
81: wwsetjmp = 0;
82: wwclrintr();
83: return;
84: }
85: /*
86: * Defensive code. If somebody else (for example,
87: * wall) clears the ASYNC flag on us, we will block
88: * forever. So we need a finite timeout and set
89: * the flag again. Anything more clever will probably
90: * need even more system calls. (This is a bug
91: * in the kernel.)
92: * I don't like this one bit.
93: */
94: (void) fcntl(0, F_SETFL, wwnewtty.ww_fflags);
95: tv.tv_sec = 30;
96: tv.tv_usec = 0;
97: } else {
98: tv.tv_sec = 0;
99: tv.tv_usec = 10000;
100: }
101: wwnselect++;
102: n = select(wwdtablesize, &imask, (fd_set *)0, (fd_set *)0, &tv);
103: wwsetjmp = 0;
104: noblock = 0;
105:
106: if (n < 0)
107: wwnselecte++;
108: else if (n == 0)
109: wwnselectz++;
110: else
111: for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
112: if (w->ww_pty < 0 ||
113: !FD_ISSET(w->ww_pty, &imask))
114: continue;
115: wwnwread++;
116: p = w->ww_obq;
117: if (w->ww_ispty) {
118: if (p == w->ww_ob) {
119: w->ww_obp++;
120: w->ww_obq++;
121: } else
122: p--;
123: c = *p;
124: }
125: n = read(w->ww_pty, p, w->ww_obe - p);
126: if (n < 0) {
127: wwnwreade++;
128: (void) close(w->ww_pty);
129: w->ww_pty = -1;
130: } else if (n == 0) {
131: wwnwreadz++;
132: (void) close(w->ww_pty);
133: w->ww_pty = -1;
134: } else if (!w->ww_ispty) {
135: wwnwreadd++;
136: wwnwreadc += n;
137: w->ww_obq += n;
138: } else if (*p == TIOCPKT_DATA) {
139: n--;
140: wwnwreadd++;
141: wwnwreadc += n;
142: w->ww_obq += n;
143: } else {
144: wwnwreadp++;
145: if (*p & TIOCPKT_STOP)
146: w->ww_stopped = 1;
147: if (*p & TIOCPKT_START)
148: w->ww_stopped = 0;
149: if (*p & TIOCPKT_FLUSHWRITE) {
150: w->ww_stopped = 0;
151: w->ww_obq = w->ww_obp =
152: w->ww_ob;
153: }
154: }
155: if (w->ww_ispty)
156: *p = c;
157: }
158: /*
159: * Try the current window first, if there is output
160: * then process it and go back to the top to try again.
161: * This can lead to starvation of the other windows,
162: * but presumably that what we want.
163: * Update will eventually happen when output from wwcurwin
164: * dies down.
165: */
166: if ((w = wwcurwin) != 0 && w->ww_pty >= 0 &&
167: w->ww_obq > w->ww_obp && !w->ww_stopped) {
168: n = wwwrite(w, w->ww_obp, w->ww_obq - w->ww_obp);
169: if ((w->ww_obp += n) == w->ww_obq)
170: w->ww_obq = w->ww_obp = w->ww_ob;
171: noblock = 1;
172: continue;
173: }
174: for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw)
175: if (w->ww_pty >= 0 && w->ww_obq > w->ww_obp &&
176: !w->ww_stopped) {
177: n = wwwrite(w, w->ww_obp,
178: w->ww_obq - w->ww_obp);
179: if ((w->ww_obp += n) == w->ww_obq)
180: w->ww_obq = w->ww_obp = w->ww_ob;
181: if (wwinterrupt())
182: break;
183: }
184: }
185: }
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