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 3.8 (Berkeley) 10/13/89"; 20 #endif /* not lint */ 21 22 #include "ww.h" 23 #include <fcntl.h> 24 25 /* 26 * Tty input interrupt handler. 27 * (1) Read input into buffer (wwib*). 28 * (2) Set the interrupt flag if anything is read. 29 * Currently, the last is used to get out of the blocking 30 * select() in wwiomux(). 31 * To avoid race conditions, we only modify wwibq in here, except 32 * when the buffer is empty; and everywhere else, we only change wwibp. 33 * It should be completely safe. 34 */ 35 wwrint() 36 { 37 register n; 38 39 if (wwibp == wwibq) 40 wwibp = wwibq = wwib; 41 wwnread++; 42 (void) fcntl(0, F_SETFL, FNDELAY|wwnewtty.ww_fflags); 43 n = read(0, wwibq, wwibe - wwibq); 44 (void) fcntl(0, F_SETFL, wwnewtty.ww_fflags); 45 if (n > 0) { 46 wwibq += n; 47 wwnreadc += n; 48 wwsetintr(); 49 } else if (n == 0) 50 wwnreadz++; 51 else 52 wwnreade++; 53 } 54