1 /* 2 * Copyright (c) 1985 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 #if defined(LIBC_SCCS) && !defined(lint) 19 static char sccsid[] = "@(#)signal.c 5.3 (Berkeley) 08/02/88"; 20 #endif /* LIBC_SCCS and not lint */ 21 22 /* 23 * Almost backwards compatible signal. 24 */ 25 #include <signal.h> 26 27 int (* 28 signal(s, a))() 29 int s, (*a)(); 30 { 31 struct sigvec osv, sv; 32 static int mask[NSIG]; 33 static int flags[NSIG]; 34 35 sv.sv_handler = a; 36 sv.sv_mask = mask[s]; 37 sv.sv_flags = flags[s]; 38 if (sigvec(s, &sv, &osv) < 0) 39 return (BADSIG); 40 if (sv.sv_mask != osv.sv_mask || sv.sv_flags != osv.sv_flags) { 41 mask[s] = sv.sv_mask = osv.sv_mask; 42 flags[s] = sv.sv_flags = osv.sv_flags; 43 if (sigvec(s, &sv, 0) < 0) 44 return (BADSIG); 45 } 46 return (osv.sv_handler); 47 } 48