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 * %sccs.include.redist.c% 9 */ 10 11 #ifndef lint 12 static char sccsid[] = "@(#)wwrint.c 3.13 (Berkeley) 08/16/92"; 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 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 wwibq += n; 51 wwnreadc += n; 52 wwsetintr(); 53 } else if (n == 0) 54 wwnreadz++; 55 else 56 wwnreade++; 57 } 58