1 /* $NetBSD: sigset.c,v 1.2 2008/04/28 20:22:59 martin 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 __RCSID("$NetBSD: sigset.c,v 1.2 2008/04/28 20:22:59 martin Exp $"); 35 #endif 36 37 #include "namespace.h" 38 #include <errno.h> 39 #include <signal.h> 40 #include <stddef.h> 41 42 sig_t 43 sigset(int sig, void (*disp)(int)) 44 { 45 sigset_t set, oset; 46 struct sigaction sa, osa; 47 48 osa.sa_handler = SIG_ERR; 49 50 if (disp == SIG_HOLD) { 51 /* Add sig to current signal mask. */ 52 if (sigemptyset(&set) != 0) 53 goto out; 54 if (sigaddset(&set, sig) != 0) 55 goto out; 56 if (sigprocmask(SIG_BLOCK, &set, &oset) != 0) 57 goto out; 58 59 if (sigismember(&oset, sig)) { 60 /* Had been masked before, return SIG_HOLD. */ 61 osa.sa_handler = SIG_HOLD; 62 } else { 63 /* Return previous disposition. */ 64 (void)sigaction(sig, NULL, &osa); 65 } 66 } else if (disp == SIG_ERR) { 67 errno = EINVAL; 68 } else { 69 /* Set up and install new disposition. */ 70 sa.sa_handler = disp; 71 if (sigemptyset(&sa.sa_mask) != 0) 72 goto out; 73 sa.sa_flags = 0; 74 75 if (sigaction(sig, &sa, &osa) != 0) { 76 osa.sa_handler = SIG_ERR; 77 goto out; 78 } 79 80 /* Delete sig from current signal mask. */ 81 if (sigemptyset(&set) != 0) 82 return (SIG_ERR); 83 if (sigaddset(&set, sig) != 0) 84 return (SIG_ERR); 85 if (sigprocmask(SIG_UNBLOCK, &set, &oset) != 0) 86 return (SIG_ERR); 87 88 /* If had been masked before, return SIG_HOLD. */ 89 if (sigismember(&oset, sig)) 90 osa.sa_handler = SIG_HOLD; 91 } 92 93 out: 94 return (osa.sa_handler); 95 } 96