Annotation of embedaddon/libevent/signal.c, revision 1.1
1.1 ! misho 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: #ifdef WIN32
! 34: #define WIN32_LEAN_AND_MEAN
! 35: #include <winsock2.h>
! 36: #include <windows.h>
! 37: #undef WIN32_LEAN_AND_MEAN
! 38: #endif
! 39: #include <sys/types.h>
! 40: #ifdef HAVE_SYS_TIME_H
! 41: #include <sys/time.h>
! 42: #endif
! 43: #include <sys/queue.h>
! 44: #ifdef HAVE_SYS_SOCKET_H
! 45: #include <sys/socket.h>
! 46: #endif
! 47: #include <signal.h>
! 48: #include <stdio.h>
! 49: #include <stdlib.h>
! 50: #include <string.h>
! 51: #ifdef HAVE_UNISTD_H
! 52: #include <unistd.h>
! 53: #endif
! 54: #include <errno.h>
! 55: #ifdef HAVE_FCNTL_H
! 56: #include <fcntl.h>
! 57: #endif
! 58: #include <assert.h>
! 59:
! 60: #include "event.h"
! 61: #include "event-internal.h"
! 62: #include "evsignal.h"
! 63: #include "evutil.h"
! 64: #include "log.h"
! 65:
! 66: struct event_base *evsignal_base = NULL;
! 67:
! 68: static void evsignal_handler(int sig);
! 69:
! 70: /* Callback for when the signal handler write a byte to our signaling socket */
! 71: static void
! 72: evsignal_cb(int fd, short what, void *arg)
! 73: {
! 74: static char signals[1];
! 75: #ifdef WIN32
! 76: SSIZE_T n;
! 77: #else
! 78: ssize_t n;
! 79: #endif
! 80:
! 81: n = recv(fd, signals, sizeof(signals), 0);
! 82: if (n == -1)
! 83: event_err(1, "%s: read", __func__);
! 84: }
! 85:
! 86: #ifdef HAVE_SETFD
! 87: #define FD_CLOSEONEXEC(x) do { \
! 88: if (fcntl(x, F_SETFD, 1) == -1) \
! 89: event_warn("fcntl(%d, F_SETFD)", x); \
! 90: } while (0)
! 91: #else
! 92: #define FD_CLOSEONEXEC(x)
! 93: #endif
! 94:
! 95: int
! 96: evsignal_init(struct event_base *base)
! 97: {
! 98: int i;
! 99:
! 100: /*
! 101: * Our signal handler is going to write to one end of the socket
! 102: * pair to wake up our event loop. The event loop then scans for
! 103: * signals that got delivered.
! 104: */
! 105: if (evutil_socketpair(
! 106: AF_UNIX, SOCK_STREAM, 0, base->sig.ev_signal_pair) == -1) {
! 107: #ifdef WIN32
! 108: /* Make this nonfatal on win32, where sometimes people
! 109: have localhost firewalled. */
! 110: event_warn("%s: socketpair", __func__);
! 111: #else
! 112: event_err(1, "%s: socketpair", __func__);
! 113: #endif
! 114: return -1;
! 115: }
! 116:
! 117: FD_CLOSEONEXEC(base->sig.ev_signal_pair[0]);
! 118: FD_CLOSEONEXEC(base->sig.ev_signal_pair[1]);
! 119: base->sig.sh_old = NULL;
! 120: base->sig.sh_old_max = 0;
! 121: base->sig.evsignal_caught = 0;
! 122: memset(&base->sig.evsigcaught, 0, sizeof(sig_atomic_t)*NSIG);
! 123: /* initialize the queues for all events */
! 124: for (i = 0; i < NSIG; ++i)
! 125: TAILQ_INIT(&base->sig.evsigevents[i]);
! 126:
! 127: evutil_make_socket_nonblocking(base->sig.ev_signal_pair[0]);
! 128:
! 129: event_set(&base->sig.ev_signal, base->sig.ev_signal_pair[1],
! 130: EV_READ | EV_PERSIST, evsignal_cb, &base->sig.ev_signal);
! 131: base->sig.ev_signal.ev_base = base;
! 132: base->sig.ev_signal.ev_flags |= EVLIST_INTERNAL;
! 133:
! 134: return 0;
! 135: }
! 136:
! 137: /* Helper: set the signal handler for evsignal to handler in base, so that
! 138: * we can restore the original handler when we clear the current one. */
! 139: int
! 140: _evsignal_set_handler(struct event_base *base,
! 141: int evsignal, void (*handler)(int))
! 142: {
! 143: #ifdef HAVE_SIGACTION
! 144: struct sigaction sa;
! 145: #else
! 146: ev_sighandler_t sh;
! 147: #endif
! 148: struct evsignal_info *sig = &base->sig;
! 149: void *p;
! 150:
! 151: /*
! 152: * resize saved signal handler array up to the highest signal number.
! 153: * a dynamic array is used to keep footprint on the low side.
! 154: */
! 155: if (evsignal >= sig->sh_old_max) {
! 156: int new_max = evsignal + 1;
! 157: event_debug(("%s: evsignal (%d) >= sh_old_max (%d), resizing",
! 158: __func__, evsignal, sig->sh_old_max));
! 159: p = realloc(sig->sh_old, new_max * sizeof(*sig->sh_old));
! 160: if (p == NULL) {
! 161: event_warn("realloc");
! 162: return (-1);
! 163: }
! 164:
! 165: memset((char *)p + sig->sh_old_max * sizeof(*sig->sh_old),
! 166: 0, (new_max - sig->sh_old_max) * sizeof(*sig->sh_old));
! 167:
! 168: sig->sh_old_max = new_max;
! 169: sig->sh_old = p;
! 170: }
! 171:
! 172: /* allocate space for previous handler out of dynamic array */
! 173: sig->sh_old[evsignal] = malloc(sizeof *sig->sh_old[evsignal]);
! 174: if (sig->sh_old[evsignal] == NULL) {
! 175: event_warn("malloc");
! 176: return (-1);
! 177: }
! 178:
! 179: /* save previous handler and setup new handler */
! 180: #ifdef HAVE_SIGACTION
! 181: memset(&sa, 0, sizeof(sa));
! 182: sa.sa_handler = handler;
! 183: sa.sa_flags |= SA_RESTART;
! 184: sigfillset(&sa.sa_mask);
! 185:
! 186: if (sigaction(evsignal, &sa, sig->sh_old[evsignal]) == -1) {
! 187: event_warn("sigaction");
! 188: free(sig->sh_old[evsignal]);
! 189: sig->sh_old[evsignal] = NULL;
! 190: return (-1);
! 191: }
! 192: #else
! 193: if ((sh = signal(evsignal, handler)) == SIG_ERR) {
! 194: event_warn("signal");
! 195: free(sig->sh_old[evsignal]);
! 196: sig->sh_old[evsignal] = NULL;
! 197: return (-1);
! 198: }
! 199: *sig->sh_old[evsignal] = sh;
! 200: #endif
! 201:
! 202: return (0);
! 203: }
! 204:
! 205: int
! 206: evsignal_add(struct event *ev)
! 207: {
! 208: int evsignal;
! 209: struct event_base *base = ev->ev_base;
! 210: struct evsignal_info *sig = &ev->ev_base->sig;
! 211:
! 212: if (ev->ev_events & (EV_READ|EV_WRITE))
! 213: event_errx(1, "%s: EV_SIGNAL incompatible use", __func__);
! 214: evsignal = EVENT_SIGNAL(ev);
! 215: assert(evsignal >= 0 && evsignal < NSIG);
! 216: if (TAILQ_EMPTY(&sig->evsigevents[evsignal])) {
! 217: event_debug(("%s: %p: changing signal handler", __func__, ev));
! 218: if (_evsignal_set_handler(
! 219: base, evsignal, evsignal_handler) == -1)
! 220: return (-1);
! 221:
! 222: /* catch signals if they happen quickly */
! 223: evsignal_base = base;
! 224:
! 225: if (!sig->ev_signal_added) {
! 226: if (event_add(&sig->ev_signal, NULL))
! 227: return (-1);
! 228: sig->ev_signal_added = 1;
! 229: }
! 230: }
! 231:
! 232: /* multiple events may listen to the same signal */
! 233: TAILQ_INSERT_TAIL(&sig->evsigevents[evsignal], ev, ev_signal_next);
! 234:
! 235: return (0);
! 236: }
! 237:
! 238: int
! 239: _evsignal_restore_handler(struct event_base *base, int evsignal)
! 240: {
! 241: int ret = 0;
! 242: struct evsignal_info *sig = &base->sig;
! 243: #ifdef HAVE_SIGACTION
! 244: struct sigaction *sh;
! 245: #else
! 246: ev_sighandler_t *sh;
! 247: #endif
! 248:
! 249: /* restore previous handler */
! 250: sh = sig->sh_old[evsignal];
! 251: sig->sh_old[evsignal] = NULL;
! 252: #ifdef HAVE_SIGACTION
! 253: if (sigaction(evsignal, sh, NULL) == -1) {
! 254: event_warn("sigaction");
! 255: ret = -1;
! 256: }
! 257: #else
! 258: if (signal(evsignal, *sh) == SIG_ERR) {
! 259: event_warn("signal");
! 260: ret = -1;
! 261: }
! 262: #endif
! 263: free(sh);
! 264:
! 265: return ret;
! 266: }
! 267:
! 268: int
! 269: evsignal_del(struct event *ev)
! 270: {
! 271: struct event_base *base = ev->ev_base;
! 272: struct evsignal_info *sig = &base->sig;
! 273: int evsignal = EVENT_SIGNAL(ev);
! 274:
! 275: assert(evsignal >= 0 && evsignal < NSIG);
! 276:
! 277: /* multiple events may listen to the same signal */
! 278: TAILQ_REMOVE(&sig->evsigevents[evsignal], ev, ev_signal_next);
! 279:
! 280: if (!TAILQ_EMPTY(&sig->evsigevents[evsignal]))
! 281: return (0);
! 282:
! 283: event_debug(("%s: %p: restoring signal handler", __func__, ev));
! 284:
! 285: return (_evsignal_restore_handler(ev->ev_base, EVENT_SIGNAL(ev)));
! 286: }
! 287:
! 288: static void
! 289: evsignal_handler(int sig)
! 290: {
! 291: int save_errno = errno;
! 292:
! 293: if (evsignal_base == NULL) {
! 294: event_warn(
! 295: "%s: received signal %d, but have no base configured",
! 296: __func__, sig);
! 297: return;
! 298: }
! 299:
! 300: evsignal_base->sig.evsigcaught[sig]++;
! 301: evsignal_base->sig.evsignal_caught = 1;
! 302:
! 303: #ifndef HAVE_SIGACTION
! 304: signal(sig, evsignal_handler);
! 305: #endif
! 306:
! 307: /* Wake up our notification mechanism */
! 308: send(evsignal_base->sig.ev_signal_pair[0], "a", 1, 0);
! 309: errno = save_errno;
! 310: }
! 311:
! 312: void
! 313: evsignal_process(struct event_base *base)
! 314: {
! 315: struct evsignal_info *sig = &base->sig;
! 316: struct event *ev, *next_ev;
! 317: sig_atomic_t ncalls;
! 318: int i;
! 319:
! 320: base->sig.evsignal_caught = 0;
! 321: for (i = 1; i < NSIG; ++i) {
! 322: ncalls = sig->evsigcaught[i];
! 323: if (ncalls == 0)
! 324: continue;
! 325: sig->evsigcaught[i] -= ncalls;
! 326:
! 327: for (ev = TAILQ_FIRST(&sig->evsigevents[i]);
! 328: ev != NULL; ev = next_ev) {
! 329: next_ev = TAILQ_NEXT(ev, ev_signal_next);
! 330: if (!(ev->ev_events & EV_PERSIST))
! 331: event_del(ev);
! 332: event_active(ev, EV_SIGNAL, ncalls);
! 333: }
! 334:
! 335: }
! 336: }
! 337:
! 338: void
! 339: evsignal_dealloc(struct event_base *base)
! 340: {
! 341: int i = 0;
! 342: if (base->sig.ev_signal_added) {
! 343: event_del(&base->sig.ev_signal);
! 344: base->sig.ev_signal_added = 0;
! 345: }
! 346: for (i = 0; i < NSIG; ++i) {
! 347: if (i < base->sig.sh_old_max && base->sig.sh_old[i] != NULL)
! 348: _evsignal_restore_handler(base, i);
! 349: }
! 350:
! 351: if (base->sig.ev_signal_pair[0] != -1) {
! 352: EVUTIL_CLOSESOCKET(base->sig.ev_signal_pair[0]);
! 353: base->sig.ev_signal_pair[0] = -1;
! 354: }
! 355: if (base->sig.ev_signal_pair[1] != -1) {
! 356: EVUTIL_CLOSESOCKET(base->sig.ev_signal_pair[1]);
! 357: base->sig.ev_signal_pair[1] = -1;
! 358: }
! 359: base->sig.sh_old_max = 0;
! 360:
! 361: /* per index frees are handled in evsig_del() */
! 362: if (base->sig.sh_old) {
! 363: free(base->sig.sh_old);
! 364: base->sig.sh_old = NULL;
! 365: }
! 366: }
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>
![[BACK]](/icons/cvsweb/back.gif){kind=icon}
Return to signal.c CVS log ![[TXT]](/icons/cvsweb/text.gif){kind=icon}
![[DIR]](/icons/cvsweb/dir.gif){kind=icon}
Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / libevent