2 * IRC - Internet Relay Chat, ircd/ircd_signal.c
3 * Copyright (C) 1990 Jarkko Oikarinen and
4 * University of Oulu, Computing Center
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 1, or (at your option)
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 * @brief Signal handlers for ircu.
27 #include "ircd_alloc.h"
28 #include "ircd_events.h"
30 #include "ircd_signal.h"
33 /* #include <assert.h> -- Now using assert in ircd_log.h */
39 /** Records a function to be called when a child process terminates. */
41 struct ChildRecord *next;
47 /** Counts various types of signals that we receive. */
48 static struct tag_SignalCounter {
49 unsigned int alrm; /**< Received SIGALRM count. */
50 unsigned int hup; /**< Received SIGHUP count. */
51 unsigned int chld; /**< Received SIGCHLD count. */
54 /** Event generator for SIGHUP. */
55 static struct Signal sig_hup;
56 /** Event generator for SIGINT. */
57 static struct Signal sig_int;
58 /** Event generator for SIGTERM. */
59 static struct Signal sig_term;
60 /** Event generator for SIGCHLD. */
61 static struct Signal sig_chld;
62 /** List of active child process callback requests. */
63 static struct ChildRecord *children;
64 /** List of inactive (free) child records. */
65 static struct ChildRecord *crec_freelist;
67 /* Make sure we have a definition for SIGCHLD. */
69 # define SIGCHLD SIGCLD
72 /** Signal handler for SIGALRM.
73 * @param[in] sig Signal number (ignored).
75 static void sigalrm_handler(int sig)
80 /** Signal callback for SIGTERM.
81 * @param[in] ev Signal event descriptor.
83 static void sigterm_callback(struct Event* ev)
85 assert(0 != ev_signal(ev));
86 assert(ET_SIGNAL == ev_type(ev));
87 assert(SIGTERM == sig_signal(ev_signal(ev)));
88 assert(SIGTERM == ev_data(ev));
90 server_die("received signal SIGTERM");
93 /** Signal callback for SIGHUP.
94 * @param[in] ev Signal event descriptor.
96 static void sighup_callback(struct Event* ev)
98 assert(0 != ev_signal(ev));
99 assert(ET_SIGNAL == ev_type(ev));
100 assert(SIGHUP == sig_signal(ev_signal(ev)));
101 assert(SIGHUP == ev_data(ev));
107 /** Signal callback for SIGINT.
108 * @param[in] ev Signal event descriptor.
110 static void sigint_callback(struct Event* ev)
112 assert(0 != ev_signal(ev));
113 assert(ET_SIGNAL == ev_type(ev));
114 assert(SIGINT == sig_signal(ev_signal(ev)));
115 assert(SIGINT == ev_data(ev));
117 server_restart("caught signal: SIGINT");
120 /** Allocate a child callback record.
121 * @return Newly allocated callback record.
123 static struct ChildRecord *alloc_crec(void)
125 struct ChildRecord *crec;
129 crec = crec_freelist;
130 crec_freelist = crec->next;
134 crec = MyCalloc(1, sizeof(*crec));
137 memset(crec, 0, sizeof(*crec));
142 /** Release \a crec, which is after \a prev.
143 * @param[in] crec Child process callback record to release.
145 static void release_crec(struct ChildRecord *crec)
147 memset(crec, 0, sizeof(*crec));
148 crec->next = crec_freelist;
149 crec_freelist = crec;
152 /** Register a function to be called when a child process terminates.
153 * @param[in] child Child process ID.
154 * @param[in] call Function to call when process \a child terminates.
155 * @param[in] datum Additional data parameter to pass to \a call.
157 void register_child(pid_t child, SigChldCallBack call, void *datum)
159 struct ChildRecord *crec;
162 /* Link into #children list. */
163 crec->next = children;
165 /* Fill in user fields. */
171 /** Unregister all callbacks for a child process, optionally calling
173 * @param[in] child Child process ID to unregister.
174 * @param[in] do_call If non-zero, make the callbacks.
175 * @param[in] status If \a do_call is non-zero, the child's exit status.
177 static void do_unregister_child(pid_t child, int do_call, int status)
179 struct ChildRecord *crec = children;
180 struct ChildRecord *prev = NULL;
184 if (crec->cpid == child)
187 crec->call(child, crec->datum, status);
190 prev->next = crec->next;
192 children = crec->next;
198 crec = prev ? prev->next : children;
202 /** Unregister all callbacks for a child process.
203 * @param[in] child Child process ID to unregister.
205 void unregister_child(pid_t child)
207 do_unregister_child(child, 0, 0);
210 /** Signal handler for SIGCHLD.
211 * @param[in] ev Signal event descriptor.
213 static void sigchld_callback(struct Event *ev)
218 ++SignalCounter.chld;
220 cpid = waitpid(-1, &status, WNOHANG);
222 do_unregister_child(cpid, 1, status);
226 /** Register all necessary signal handlers. */
227 void setup_signals(void)
229 struct sigaction act;
231 act.sa_handler = SIG_IGN;
233 sigemptyset(&act.sa_mask);
234 sigaddset(&act.sa_mask, SIGPIPE);
235 sigaddset(&act.sa_mask, SIGALRM);
237 sigaddset(&act.sa_mask, SIGWINCH);
238 sigaction(SIGWINCH, &act, 0);
240 sigaction(SIGPIPE, &act, 0);
242 act.sa_handler = sigalrm_handler;
243 sigaction(SIGALRM, &act, 0);
245 signal_add(&sig_hup, sighup_callback, 0, SIGHUP);
246 signal_add(&sig_int, sigint_callback, 0, SIGINT);
247 signal_add(&sig_term, sigterm_callback, 0, SIGTERM);
248 signal_add(&sig_chld, sigchld_callback, 0, SIGCHLD);
250 #ifdef HAVE_RESTARTABLE_SYSCALLS
252 * At least on Apollo sr10.1 it seems continuing system calls
253 * after signal is the default. The following 'siginterrupt'
254 * should change that default to interrupting calls.
256 siginterrupt(SIGALRM, 1);
260 /** Kill and clean up all child processes. */
261 void reap_children(void)
263 /* Send SIGTERM to all children in process group. Sleep for a
264 * second to let them exit before we try to clean them up.
268 sigchld_callback(NULL);