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 * %sccs.include.redist.c%
9 */
10
11 #ifndef lint
12 static char sccsid[] = "@(#)wwrint.c 8.1 (Berkeley) 06/06/93";
13 #endif /* not lint */
14
15 #include "ww.h"
16 #include "tt.h"
17 #if defined(OLD_TTY) || defined(VMIN_BUG)
18 #include <fcntl.h>
19 #endif
20
21 /*
22 * Tty input interrupt handler.
23 * (1) Read input into buffer (wwib*).
24 * (2) Set the interrupt flag if anything is read.
25 * Currently, the last is used to get out of the blocking
26 * select() in wwiomux().
27 * To avoid race conditions, we only modify wwibq in here, except
28 * when the buffer is empty; and everywhere else, we only change wwibp.
29 * It should be completely safe.
30 */
31 void
wwrint()32 wwrint()
33 {
34 register n;
35
36 if (wwibp == wwibq)
37 wwibp = wwibq = wwib;
38 wwnread++;
39 #if defined(OLD_TTY) || defined(VMIN_BUG)
40 /* we have set c_cc[VMIN] to 0 */
41 (void) fcntl(0, F_SETFL, O_NONBLOCK|wwnewtty.ww_fflags);
42 #endif
43 n = read(0, wwibq, wwibe - wwibq);
44 #if defined(OLD_TTY) || defined(VMIN_BUG)
45 (void) fcntl(0, F_SETFL, wwnewtty.ww_fflags);
46 #endif
47 if (n > 0) {
48 if (tt.tt_rint)
49 n = (*tt.tt_rint)(wwibq, n);
50 if (n > 0) {
51 wwibq += n;
52 wwnreadc += n;
53 /*
54 * Hasten or delay the next checkpoint,
55 * as the case may be.
56 */
57 if (tt.tt_checkpoint && !wwdocheckpoint)
58 (void) alarm(1);
59 wwsetintr();
60 }
61 } else if (n == 0)
62 wwnreadz++;
63 else
64 wwnreade++;
65 }
66