1 /* 2 * Copyright (c) 1983 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18 #ifndef lint 19 static char sccsid[] = "@(#)wwrint.c 3.7 (Berkeley) 06/29/88"; 20 #endif /* not lint */ 21 22 #include "ww.h" 23 #include <fcntl.h> 24 #include <sys/signal.h> 25 26 /* 27 * Tty input interrupt handler. 28 * (1) Read input into buffer (wwib*). 29 * (2) Set the interrupt flag if anything is read. 30 * Currently, the last is used to get out of the blocking 31 * select() in wwiomux(). 32 * To avoid race conditions, we only modify wwibq in here, except 33 * when the buffer is empty; and everywhere else, we only change wwibp. 34 * It should be completely safe. 35 */ 36 wwrint() 37 { 38 register n; 39 40 if (wwibp == wwibq) 41 wwibp = wwibq = wwib; 42 wwnread++; 43 (void) fcntl(0, F_SETFL, FNDELAY|wwnewtty.ww_fflags); 44 n = read(0, wwibq, wwibe - wwibq); 45 (void) fcntl(0, F_SETFL, wwnewtty.ww_fflags); 46 if (n > 0) { 47 wwibq += n; 48 wwnreadc += n; 49 wwsetintr(); 50 } else if (n == 0) 51 wwnreadz++; 52 else 53 wwnreade++; 54 } 55