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sigset.c revision 1.1 
      1 /*	$NetBSD: sigset.c,v 1.1 2003/01/15 23:55:43 kleink Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2003 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Klaus Klein.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #if defined(LIBC_SCCS) && !defined(lint)
     41 __RCSID("$NetBSD: sigset.c,v 1.1 2003/01/15 23:55:43 kleink Exp $");
     42 #endif
     43 
     44 #include "namespace.h"
     45 #include <errno.h>
     46 #include <signal.h>
     47 #include <stddef.h>
     48 
     49 sig_t
     50 sigset(int sig, void (*disp)(int))
     51 {
     52 	sigset_t set, oset;
     53 	struct sigaction sa, osa;
     54 
     55 	osa.sa_handler = SIG_ERR;
     56 
     57 	if (disp == SIG_HOLD) {
     58 		/* Add sig to current signal mask. */
     59 		if (sigemptyset(&set) != 0)
     60 			goto out;
     61 		if (sigaddset(&set, sig) != 0)
     62 			goto out;
     63 		if (sigprocmask(SIG_BLOCK, &set, &oset) != 0)
     64 			goto out;
     65 
     66 		if (sigismember(&oset, sig)) {
     67 			/* Had been masked before, return SIG_HOLD. */
     68 			osa.sa_handler = SIG_HOLD;
     69 		} else {
     70 			/* Return previous disposition. */
     71 		 	(void)sigaction(sig, NULL, &osa);
     72 		}
     73 	} else if (disp == SIG_ERR) {
     74 		errno = EINVAL;
     75 	} else {
     76 		/* Set up and install new disposition. */
     77 		sa.sa_handler = disp;
     78 		if (sigemptyset(&sa.sa_mask) != 0)
     79 			goto out;
     80 		sa.sa_flags = 0;
     81 
     82 		if (sigaction(sig, &sa, &osa) != 0) {
     83 			osa.sa_handler = SIG_ERR;
     84 			goto out;
     85 		}
     86 
     87 		/* Delete sig from current signal mask. */
     88 		if (sigemptyset(&set) != 0)
     89 			return (SIG_ERR);
     90 		if (sigaddset(&set, sig) != 0)
     91 			return (SIG_ERR);
     92 		if (sigprocmask(SIG_UNBLOCK, &set, &oset) != 0)
     93 			return (SIG_ERR);
     94 
     95 		/* If had been masked before, return SIG_HOLD. */
     96 		if (sigismember(&oset, sig))
     97 			osa.sa_handler = SIG_HOLD;
     98 	}
     99 
    100  out:
    101 	return (osa.sa_handler);
    102 }
    103