contrib/libevent/signal.c

   1 /*      $OpenBSD: select.c,v 1.2 2002/06/25 15:50:15 mickey Exp $       */
   2
   3 /*
   4  * Copyright 2000-2002 Niels Provos <provos@citi.umich.edu>
   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  * 3. The name of the author may not be used to endorse or promote products
  16  *    derived from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29 #ifdef HAVE_CONFIG_H
  30 #include "config.h"
  31 #endif
  32
  33 #include <sys/types.h>
  34 #include <sys/tree.h>
  35 #ifdef HAVE_SYS_TIME_H
  36 #include <sys/time.h>
  37 #else
  38 #include <sys/_time.h>
  39 #endif
  40 #include <sys/queue.h>
  41 #include <sys/socket.h>
  42 #include <signal.h>
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include <unistd.h>
  47 #include <errno.h>
  48 #ifdef HAVE_FCNTL_H
  49 #include <fcntl.h>
  50 #endif
  51 #include <assert.h>
  52
  53 #include "event.h"
  54 #include "event-internal.h"
  55 #include "evsignal.h"
  56 #include "log.h"
  57
  58 struct event_base *evsignal_base = NULL;
  59
  60 static void evsignal_handler(int sig);
  61
  62 /* Callback for when the signal handler write a byte to our signaling socket */
  63 static void
  64 evsignal_cb(int fd, short what, void *arg)
  65 {
  66         static char signals[100];
  67         struct event *ev = arg;
  68         ssize_t n;
  69
  70         n = read(fd, signals, sizeof(signals));
  71         if (n == -1)
  72                 event_err(1, "%s: read", __func__);
  73         event_add(ev, NULL);
  74 }
  75
  76 #ifdef HAVE_SETFD
  77 #define FD_CLOSEONEXEC(x) do { \
  78         if (fcntl(x, F_SETFD, 1) == -1) \
  79                 event_warn("fcntl(%d, F_SETFD)", x); \
  80 } while (0)
  81 #else
  82 #define FD_CLOSEONEXEC(x)
  83 #endif
  84
  85 void
  86 evsignal_init(struct event_base *base)
  87 {
  88         /*
  89          * Our signal handler is going to write to one end of the socket
  90          * pair to wake up our event loop.  The event loop then scans for
  91          * signals that got delivered.
  92          */
  93         if (socketpair(AF_UNIX, SOCK_STREAM, 0, base->sig.ev_signal_pair) == -1)
  94                 event_err(1, "%s: socketpair", __func__);
  95
  96         FD_CLOSEONEXEC(base->sig.ev_signal_pair[0]);
  97         FD_CLOSEONEXEC(base->sig.ev_signal_pair[1]);
  98         base->sig.evsignal_caught = 0;
  99         memset(&base->sig.evsigcaught, 0, sizeof(sig_atomic_t)*NSIG);
 100
 101         fcntl(base->sig.ev_signal_pair[0], F_SETFL, O_NONBLOCK);
 102
 103         event_set(&base->sig.ev_signal, base->sig.ev_signal_pair[1], EV_READ,
 104             evsignal_cb, &base->sig.ev_signal);
 105         base->sig.ev_signal.ev_base = base;
 106         base->sig.ev_signal.ev_flags |= EVLIST_INTERNAL;
 107 }
 108
 109 int
 110 evsignal_add(struct event *ev)
 111 {
 112         int evsignal;
 113         struct sigaction sa;
 114         struct event_base *base = ev->ev_base;
 115
 116         if (ev->ev_events & (EV_READ|EV_WRITE))
 117                 event_errx(1, "%s: EV_SIGNAL incompatible use", __func__);
 118         evsignal = EVENT_SIGNAL(ev);
 119
 120         memset(&sa, 0, sizeof(sa));
 121         sa.sa_handler = evsignal_handler;
 122         sigfillset(&sa.sa_mask);
 123         sa.sa_flags |= SA_RESTART;
 124         /* catch signals if they happen quickly */
 125         evsignal_base = base;
 126
 127         if (sigaction(evsignal, &sa, NULL) == -1)
 128                 return (-1);
 129
 130         if (!base->sig.ev_signal_added) {
 131                 base->sig.ev_signal_added = 1;
 132                 event_add(&base->sig.ev_signal, NULL);
 133         }
 134
 135         return (0);
 136 }
 137
 138 int
 139 evsignal_del(struct event *ev)
 140 {
 141         return (sigaction(EVENT_SIGNAL(ev),(struct sigaction *)SIG_DFL, NULL));
 142 }
 143
 144 static void
 145 evsignal_handler(int sig)
 146 {
 147         int save_errno = errno;
 148
 149         if(evsignal_base == NULL) {
 150                 event_warn(
 151                         "%s: received signal %s, but have no base configured",
 152                         __func__, sig);
 153                 return;
 154         }
 155
 156         evsignal_base->sig.evsigcaught[sig]++;
 157         evsignal_base->sig.evsignal_caught = 1;
 158
 159         /* Wake up our notification mechanism */
 160         write(evsignal_base->sig.ev_signal_pair[0], "a", 1);
 161         errno = save_errno;
 162 }
 163
 164 void
 165 evsignal_process(struct event_base *base)
 166 {
 167         struct event *ev;
 168         sig_atomic_t ncalls;
 169
 170         base->sig.evsignal_caught = 0;
 171         TAILQ_FOREACH(ev, &base->sig.signalqueue, ev_signal_next) {
 172                 ncalls = base->sig.evsigcaught[EVENT_SIGNAL(ev)];
 173                 if (ncalls) {
 174                         if (!(ev->ev_events & EV_PERSIST))
 175                                 event_del(ev);
 176                         event_active(ev, EV_SIGNAL, ncalls);
 177                         base->sig.evsigcaught[EVENT_SIGNAL(ev)] = 0;
 178                 }
 179         }
 180 }
 181
 182 void
 183 evsignal_dealloc(struct event_base *base)
 184 {
 185         if(base->sig.ev_signal_added) {
 186                 event_del(&base->sig.ev_signal);
 187                 base->sig.ev_signal_added = 0;
 188         }
 189         assert(TAILQ_EMPTY(&base->sig.signalqueue));
 190
 191         close(base->sig.ev_signal_pair[0]);
 192         base->sig.ev_signal_pair[0] = -1;
 193         close(base->sig.ev_signal_pair[1]);
 194         base->sig.ev_signal_pair[1] = -1;
 195 }