1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1997 - 1999, 2001 Brian Somers <brian@Awfulhak.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 #include <sys/types.h> 32 33 #include <signal.h> 34 35 #include "log.h" 36 #include "sig.h" 37 38 static int caused[NSIG]; /* An array of pending signals */ 39 static int necessary; /* Anything set ? */ 40 static sig_type handler[NSIG]; /* all start at SIG_DFL */ 41 42 43 /* 44 * Record a signal in the "caused" array 45 * 46 * This function is the only thing actually called in signal context. It 47 * records that a signal has been caused and that sig_Handle() should be 48 * called (in non-signal context) as soon as possible to process that 49 * signal. 50 */ 51 static void 52 signal_recorder(int sig) 53 { 54 caused[sig - 1]++; 55 necessary = 1; 56 } 57 58 59 /* 60 * Set up signal_recorder to handle the given sig and record ``fn'' as 61 * the function to ultimately call in sig_Handle(). ``fn'' will not be 62 * called in signal context (as sig_Handle() is not called in signal 63 * context). 64 */ 65 sig_type 66 sig_signal(int sig, sig_type fn) 67 { 68 sig_type Result; 69 70 if (sig <= 0 || sig > NSIG) { 71 /* Oops - we must be a bit out of date (too many sigs ?) */ 72 log_Printf(LogALERT, "Eeek! %s:%d: I must be out of date!\n", 73 __FILE__, __LINE__); 74 return signal(sig, fn); 75 } 76 Result = handler[sig - 1]; 77 if (fn == SIG_DFL || fn == SIG_IGN) { 78 signal(sig, fn); 79 handler[sig - 1] = (sig_type) 0; 80 } else { 81 handler[sig - 1] = fn; 82 signal(sig, signal_recorder); 83 } 84 caused[sig - 1] = 0; 85 return Result; 86 } 87 88 89 /* 90 * Call the handlers for any pending signals 91 * 92 * This function is called from a non-signal context - in fact, it's 93 * called every time select() in DoLoop() returns - just in case 94 * select() returned due to a signal being recorded by signal_recorder(). 95 */ 96 int 97 sig_Handle() 98 { 99 int sig; 100 int got; 101 int result; 102 103 result = 0; 104 if (necessary) { 105 /* We've *probably* got something in `caused' set */ 106 necessary = 0; 107 /* `necessary' might go back to 1 while we're in here.... */ 108 do { 109 got = 0; 110 for (sig = 0; sig < NSIG; sig++) 111 if (caused[sig]) { 112 caused[sig]--; 113 got++; 114 result++; 115 (*handler[sig])(sig + 1); 116 } 117 } while (got); 118 } 119 120 return result; 121 } 122