initial support for signals (only for select now) based on code from

Dug Song <dugsong@monkey.org>


svn:r17

event.c

@@ -81,6 +81,7 @@ void	event_queue_remove(struct event *, int);
 
 static RB_HEAD(event_tree, event) timetree;
 static struct event_list activequeue;
+struct event_list signalqueue;
 struct event_list eventqueue;
 static struct timeval event_tv;
 
@@ -111,6 +112,7 @@ event_init(void)
 	RB_INIT(&timetree);
 	TAILQ_INIT(&eventqueue);
 	TAILQ_INIT(&activequeue);
+	TAILQ_INIT(&signalqueue);
 	
 	evbase = NULL;
 	for (i = 0; eventops[i] && !evbase; i++) {
@@ -129,7 +131,7 @@ int
 event_haveevents(void)
 {
 	return (RB_ROOT(&timetree) || TAILQ_FIRST(&eventqueue) ||
-	    TAILQ_FIRST(&activequeue));
+	    TAILQ_FIRST(&signalqueue) || TAILQ_FIRST(&activequeue));
 }
 
 void
@@ -285,6 +287,11 @@ event_add(struct event *ev, struct timeval *tv)
 	    !(ev->ev_flags & EVLIST_INSERTED)) {
 		event_queue_insert(ev, EVLIST_INSERTED);
 
+		return (evsel->add(evbase, ev));
+	} else if ((ev->ev_events & EV_SIGNAL) &&
+	    !(ev->ev_flags & EVLIST_SIGNAL)) {
+		event_queue_insert(ev, EVLIST_SIGNAL);
+
 		return (evsel->add(evbase, ev));
 	}
 
@@ -308,6 +315,9 @@ event_del(struct event *ev)
 	if (ev->ev_flags & EVLIST_INSERTED) {
 		event_queue_remove(ev, EVLIST_INSERTED);
 		return (evsel->del(evbase, ev));
+	} else if (ev->ev_flags & EVLIST_SIGNAL) {
+		event_queue_remove(ev, EVLIST_SIGNAL);
+		return (evsel->del(evbase, ev));
 	}
 
 	return (0);
@@ -323,12 +333,13 @@ event_active(struct event *ev, int res)
 int
 timeout_next(struct timeval *tv)
 {
+	struct timeval dflt = TIMEOUT_DEFAULT;
+
 	struct timeval now;
 	struct event *ev;
 
 	if ((ev = RB_MIN(event_tree, &timetree)) == NULL) {
-		timerclear(tv);
-		tv->tv_sec = TIMEOUT_DEFAULT;
+		*tv = dflt;
 		return (0);
 	}
 
@@ -419,6 +430,9 @@ event_queue_remove(struct event *ev, int queue)
 	case EVLIST_ACTIVE:
 		TAILQ_REMOVE(&activequeue, ev, ev_active_next);
 		break;
+	case EVLIST_SIGNAL:
+		TAILQ_REMOVE(&signalqueue, ev, ev_signal_next);
+		break;
 	case EVLIST_TIMEOUT:
 		RB_REMOVE(event_tree, &timetree, ev);
 		break;
@@ -442,6 +456,9 @@ event_queue_insert(struct event *ev, int queue)
 	case EVLIST_ACTIVE:
 		TAILQ_INSERT_TAIL(&activequeue, ev, ev_active_next);
 		break;
+	case EVLIST_SIGNAL:
+		TAILQ_INSERT_TAIL(&signalqueue, ev, ev_signal_next);
+		break;
 	case EVLIST_TIMEOUT:
 		timeout_insert(ev);
 		break;

event.h

@@ -36,6 +36,7 @@ extern "C" {
 
 #define EVLIST_TIMEOUT	0x01
 #define EVLIST_INSERTED	0x02
+#define EVLIST_SIGNAL	0x04
 #define EVLIST_ACTIVE	0x08
 #define EVLIST_INIT	0x80
 
@@ -45,6 +46,7 @@ extern "C" {
 #define EV_TIMEOUT	0x01
 #define EV_READ		0x02
 #define EV_WRITE	0x04
+#define EV_SIGNAL	0x08
 
 /* Fix so that ppl dont have to run with <sys/queue.h> */
 #ifndef TAILQ_ENTRY
@@ -69,6 +71,7 @@ struct {								\
 struct event {
 	TAILQ_ENTRY (event) ev_next;
 	TAILQ_ENTRY (event) ev_active_next;
+	TAILQ_ENTRY (event) ev_signal_next;
 	RB_ENTRY (event) ev_timeout_node;
 
 	int ev_fd;
@@ -83,6 +86,9 @@ struct event {
 	int ev_flags;
 };
 
+#define EVENT_SIGNAL(ev)	ev->ev_fd
+#define EVENT_FD(ev)		ev->ev_fd
+
 #ifdef _EVENT_DEFINED_TQENTRY
 #undef TAILQ_ENTRY
 #undef _EVENT_DEFINED_TQENTRY
@@ -103,7 +109,7 @@ struct eventop {
 	int (*dispatch)(void *, struct timeval *);
 };
 
-#define TIMEOUT_DEFAULT	5
+#define TIMEOUT_DEFAULT	{0, 250000L}
 
 void event_init(void);
 int event_dispatch(void);

sample/Makefile.am

@@ -3,9 +3,10 @@ AUTOMAKE_OPTIONS = foreign no-dependencies
 LDADD = -L.. -levent
 CPPFPLAGS = -I..
 
-noinst_PROGRAMS = event-test time-test
+noinst_PROGRAMS = event-test time-test signal-test
 
 event_test_sources = event-test.c
 time_test_sources = time-test.c
+signal_test_sources = signal-test.c
 
 DISTCLEANFILES = *~

sample/signal-test.c

@@ -0,0 +1,52 @@
+/*
+ * Compile with:
+ * cc -I/usr/local/include -o time-test time-test.c -L/usr/local/lib -levent
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/queue.h>
+#include <sys/time.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include <event.h>
+
+int called = 0;
+
+void
+signal_cb(int fd, short event, void *arg)
+{
+	struct event *signal = arg;
+
+	printf("%s: got signal %d\n", __FUNCTION__, EVENT_SIGNAL(signal));
+
+	if (called >= 2)
+		event_del(signal);
+
+	called++;
+}
+
+int
+main (int argc, char **argv)
+{
+	struct event signal_int;
+ 
+	/* Initalize the event library */
+	event_init();
+
+	/* Initalize one event */
+	event_set(&signal_int, SIGINT, EV_SIGNAL, signal_cb, &signal_int);
+
+	event_add(&signal_int, NULL);
+
+	event_dispatch();
+
+	return (0);
+}
+

select.c

@@ -32,6 +32,7 @@
 #include <sys/types.h>
 #include <sys/time.h>
 #include <sys/queue.h>
+#include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -49,19 +50,25 @@
 
 extern struct event_list timequeue;
 extern struct event_list eventqueue;
-extern struct event_list addqueue;
+extern struct event_list signalqueue;
 
 #ifndef howmany
 #define        howmany(x, y)   (((x)+((y)-1))/(y))
 #endif
 
+int evsigcaught[NSIG];
+
 struct selectop {
 	int event_fds;		/* Highest fd in fd set */
 	int event_fdsz;
 	fd_set *event_readset;
 	fd_set *event_writeset;
+	sigset_t evsigmask;
 } sop;
 
+void signal_process(void);
+int signal_recalc(void);
+
 void *select_init	(void);
 int select_add		(void *, struct event *);
 int select_del		(void *, struct event *);
@@ -82,6 +89,8 @@ select_init(void)
 {
 	memset(&sop, 0, sizeof(sop));
 
+	sigemptyset(&sop.evsigmask);
+
 	return (&sop);
 }
 
@@ -130,7 +139,7 @@ select_recalc(void *arg, int max)
 		sop->event_fdsz = fdsz;
 	}
 
-	return (0);
+	return (signal_recalc());
 }
 
 int
@@ -150,9 +159,16 @@ select_dispatch(void *arg, struct timeval *tv)
 			FD_SET(ev->ev_fd, sop->event_readset);
 	}
 
+	if (signal_deliver() == -1)
+		return (-1);
 
-	if ((res = select(sop->event_fds + 1, sop->event_readset, 
-		 sop->event_writeset, NULL, tv)) == -1) {
+	res = select(sop->event_fds + 1, sop->event_readset, 
+	    sop->event_writeset, NULL, tv);
+
+	if (signal_recalc() == -1)
+		return (-1);
+
+	if (res == -1) {
 		if (errno != EINTR) {
 			log_error("select");
 			return (-1);
@@ -184,6 +200,8 @@ select_dispatch(void *arg, struct timeval *tv)
 
 	sop->event_fds = maxfd;
 
+	signal_process();
+
 	return (0);
 }
 
@@ -192,6 +210,18 @@ select_add(void *arg, struct event *ev)
 {
 	struct selectop *sop = arg;
 
+	if (ev->ev_events & EV_SIGNAL) {
+		int signal;
+
+		if (ev->ev_events & (EV_READ|EV_WRITE))
+			errx(1, "%s: EV_SIGNAL incompatible use",
+			    __FUNCTION__);
+		signal = EVENT_SIGNAL(ev);
+		sigaddset(&sop->evsigmask, signal);
+
+		return (0);
+	}
+
 	/* 
 	 * Keep track of the highest fd, so that we can calculate the size
 	 * of the fd_sets for select(2)
@@ -209,5 +239,64 @@ select_add(void *arg, struct event *ev)
 int
 select_del(void *arg, struct event *ev)
 {
+	struct selectop *sop = arg;
+
+	int signal;
+
+	if (!(ev->ev_events & EV_SIGNAL))
+		return (0);
+
+	signal = EVENT_SIGNAL(ev);
+	sigdelset(&sop->evsigmask, signal);
+
+	return (sigaction(EVENT_SIGNAL(ev),(struct sigaction *)SIG_DFL, NULL));
+}
+
+static void
+signal_handler(int sig)
+{
+	evsigcaught[sig]++;
+}
+
+int
+signal_recalc(void)
+{
+	struct sigaction sa;
+	struct event *ev;
+
+	if (sigprocmask(SIG_BLOCK, &sop.evsigmask, NULL) == -1)
+		return (-1);
+	
+	/* Reinstall our signal handler. */
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = signal_handler;
+	sa.sa_mask = sop.evsigmask;
+	sa.sa_flags |= SA_RESTART;
+	
+	TAILQ_FOREACH(ev, &signalqueue, ev_signal_next) {
+		if (sigaction(EVENT_SIGNAL(ev), &sa, NULL) == -1)
+			return (-1);
+	}
 	return (0);
 }
+
+int
+signal_deliver(void)
+{
+	return (sigprocmask(SIG_UNBLOCK, &sop.evsigmask, NULL));
+	/* XXX - pending signals handled here */
+}
+
+void
+signal_process(void)
+{
+	struct event *ev;
+
+	TAILQ_FOREACH(ev, &signalqueue, ev_signal_next) {
+		if (evsigcaught[EVENT_SIGNAL(ev)])
+			event_active(ev, EV_SIGNAL);
+	}
+
+	memset(evsigcaught, 0, sizeof(evsigcaught));
+}
+