r20930: use sigaction() instead of signal()

add support for sa_flags argument to event_add_signal(). These are
passed to sigaction(). Special handling is provided for SA_RESETHAND
(which tells the event system to remove the handler after the signal)
and SA_SIGINFO which allows the siginfo structure to be received per
signal
(This used to be commit 1bb10b6cf7)

source4/lib/events/events.c

@@ -241,14 +241,18 @@ struct timed_event *event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ct
 
 /*
   add a signal event
+
+  sa_flags are flags to sigaction(2)
+
   return NULL on failure
 */
 struct signal_event *event_add_signal(struct event_context *ev, TALLOC_CTX *mem_ctx,
 				      int signum,
+				      int sa_flags,
 				      event_signal_handler_t handler, 
 				      void *private_data)
 {
-	return ev->ops->add_signal(ev, mem_ctx, signum, handler, private_data);
+	return ev->ops->add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data);
 }
 
 /*

source4/lib/events/events.h

@@ -36,7 +36,7 @@ typedef void (*event_fd_handler_t)(struct event_context *, struct fd_event *,
 typedef void (*event_timed_handler_t)(struct event_context *, struct timed_event *, 
 				      struct timeval , void *);
 typedef void (*event_signal_handler_t)(struct event_context *, struct signal_event *, 
-				       int , int, void *);
+				       int , int, void *, void *);
 typedef void (*event_aio_handler_t)(struct event_context *, struct aio_event *, 
 				    int, void *);
 
@@ -54,7 +54,7 @@ struct timed_event *event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ct
 				    void *private);
 
 struct signal_event *event_add_signal(struct event_context *ev, TALLOC_CTX *mem_ctx,
-				      int signum,
+				      int signum, int sa_flags,
 				      event_signal_handler_t handler, 
 				      void *private);
 

source4/lib/events/events_internal.h

@@ -50,7 +50,7 @@ struct event_ops {
 	/* signal functions */
 	struct signal_event *(*add_signal)(struct event_context *ev, 
 					   TALLOC_CTX *mem_ctx,
-					   int signum,
+					   int signum, int sa_flags,
 					   event_signal_handler_t handler, 
 					   void *private_data);
 
@@ -89,6 +89,7 @@ struct signal_event {
 	event_signal_handler_t handler;
 	void *private_data;
 	int signum;
+	int sa_flags;
 };
 
 /* aio event is private to the aio backend */
@@ -122,6 +123,7 @@ struct timeval common_event_loop_delay(struct event_context *);
 struct signal_event *common_event_add_signal(struct event_context *ev, 
 					     TALLOC_CTX *mem_ctx,
 					     int signum,
+					     int sa_flags,
 					     event_signal_handler_t handler, 
 					     void *private_data);
 int common_event_check_signal(struct event_context *ev);

source4/lib/events/events_signal.c

@@ -29,14 +29,22 @@
 
 #define NUM_SIGNALS 64
 
+/* maximum number of SA_SIGINFO signals to hold in the queue */
+#define SA_INFO_QUEUE_COUNT 10
+
 /*
   the poor design of signals means that this table must be static global
 */
 static struct {
 	struct signal_event *sig_handlers[NUM_SIGNALS];
+	struct sigaction oldact[NUM_SIGNALS];
 	uint32_t signal_count[NUM_SIGNALS];
 	uint32_t got_signal;
 	int pipe_hack[2];
+#ifdef SA_SIGINFO
+	/* with SA_SIGINFO we get quite a lot of info per signal */
+	siginfo_t sig_info[NUM_SIGNALS][SA_INFO_QUEUE_COUNT];
+#endif
 } sig_state;
 
 
@@ -52,6 +60,27 @@ static void signal_handler(int signum)
 	write(sig_state.pipe_hack[1], &c, 1);
 }
 
+#ifdef SA_SIGINFO
+/*
+  signal handler with SA_SIGINFO - redirects to registered signals
+*/
+static void signal_handler_info(int signum, siginfo_t *info, void *uctx)
+{
+	sig_state.sig_info[signum][sig_state.signal_count[signum]] = *info;
+
+	signal_handler(signum);
+
+	/* handle SA_SIGINFO */
+	if (sig_state.signal_count[signum] == SA_INFO_QUEUE_COUNT) {
+		/* we've filled the info array - block this signal until
+		   these ones are delivered */
+		sigset_t set;
+		sigemptyset(&set);
+		sigaddset(&set, signum);
+		sigprocmask(SIG_BLOCK, &set, NULL);
+	}
+}
+#endif
 
 /*
   destroy a signal event
@@ -61,7 +90,8 @@ static int signal_event_destructor(struct signal_event *se)
 	se->event_ctx->num_signal_handlers--;
 	DLIST_REMOVE(sig_state.sig_handlers[se->signum], se);
 	if (sig_state.sig_handlers[se->signum] == NULL) {
-		signal(se->signum, SIG_DFL);
+		/* restore old handler, if any */
+		sigaction(se->signum, &sig_state.oldact[se->signum], NULL);
 	}
 	return 0;
 }
@@ -82,10 +112,11 @@ static void signal_pipe_handler(struct event_context *ev, struct fd_event *fde,
   return NULL on failure (memory allocation error)
 */
 struct signal_event *common_event_add_signal(struct event_context *ev, 
-					    TALLOC_CTX *mem_ctx,
+					     TALLOC_CTX *mem_ctx,
-					    int signum,
+					     int signum,
-					    event_signal_handler_t handler, 
+					     int sa_flags,
-					    void *private_data) 
+					     event_signal_handler_t handler, 
+					     void *private_data) 
 {
 	struct signal_event *se;
 
@@ -100,15 +131,32 @@ struct signal_event *common_event_add_signal(struct event_context *ev,
 	se->handler		= handler;
 	se->private_data	= private_data;
 	se->signum              = signum;
+	se->sa_flags            = sa_flags;
 
+	/* only install a signal handler if not already installed */
 	if (sig_state.sig_handlers[signum] == NULL) {
-		signal(signum, signal_handler);
+		struct sigaction act;
+		ZERO_STRUCT(act);
+		act.sa_handler   = signal_handler;
+		act.sa_flags = sa_flags;
+#ifdef SA_SIGINFO
+		if (sa_flags & SA_SIGINFO) {
+			act.sa_handler   = NULL;
+			act.sa_sigaction = signal_handler_info;
+		}
+#endif
+		if (sigaction(signum, &act, &sig_state.oldact[signum]) == -1) {
+			talloc_free(se);
+			return NULL;
+		}
 	}
 
 	DLIST_ADD(sig_state.sig_handlers[signum], se);
 
 	talloc_set_destructor(se, signal_event_destructor);
 
+	/* we need to setup the pipe hack handler if not already
+	   setup */
 	if (ev->pipe_fde == NULL) {
 		if (sig_state.pipe_hack[0] == 0 && 
 		    sig_state.pipe_hack[1] == 0) {
@@ -142,7 +190,29 @@ int common_event_check_signal(struct event_context *ev)
 			struct signal_event *se, *next;
 			for (se=sig_state.sig_handlers[i];se;se=next) {
 				next = se->next;
-				se->handler(ev, se, i, count, se->private_data);
+#ifdef SA_SIGINFO
+				if (se->sa_flags & SA_SIGINFO) {
+					int j;
+					for (j=0;j<count;j++) {
+						se->handler(ev, se, i, 1, 
+							    (void*)&sig_state.sig_info[i][j], 
+							    se->private_data);
+					}
+					if (count == SA_INFO_QUEUE_COUNT) {
+						/* we'd filled the queue, unblock the
+						   signal now */
+						sigset_t set;
+						sigemptyset(&set);
+						sigaddset(&set, i);
+						sigprocmask(SIG_UNBLOCK, &set, NULL);
+					}
+					continue;
+				}
+#endif
+				se->handler(ev, se, i, count, NULL, se->private_data);
+				if (se->sa_flags & SA_RESETHAND) {
+					talloc_free(se);
+				}
 			}
 			sig_state.signal_count[i] -= count;
 			sig_state.got_signal -= count;

source4/lib/replace/system/wait.h

@@ -40,4 +40,8 @@
 #include <setjmp.h>
 #endif
 
+#ifndef SA_RESETHAND
+#define SA_RESETHAND SA_ONESHOT
+#endif
+
 #endif

source4/torture/local/event.c

@@ -25,63 +25,50 @@
 #include "system/filesys.h"
 #include "torture/torture.h"
 
-static int write_fd, read_fd;
-static struct fd_event *fde;
-static int te_count;
 static int fde_count;
-static struct torture_context *test;
 
 static void fde_handler(struct event_context *ev_ctx, struct fd_event *f, 
 			uint16_t flags, void *private)
 {
 	int *fd = private;
-
+	char c;
-	torture_comment(test, "event[%d] fd[%d] events[0x%08X]%s%s\n", 
+#ifdef SA_SIGINFO
-						fde_count, *fd, flags, 
+	kill(getpid(), SIGUSR1);
-					(flags & EVENT_FD_READ)?" EVENT_FD_READ":"", 
+#endif
-					(flags & EVENT_FD_WRITE)?" EVENT_FD_WRITE":"");
+	kill(getpid(), SIGALRM);
-
+	read(fd[0], &c, 1);
-	if (fde_count > 5) {
+	write(fd[1], &c, 1);
-		torture_result(test, TORTURE_FAIL, 
-					   __location__": got more than fde 5 events - bug!");
-		talloc_free(fde);
-		fde = NULL;
-		return;
-	}
-
-	event_set_fd_flags(fde, 0);
 	fde_count++;
 }
 
-static void timed_handler(struct event_context *ev_ctx, struct timed_event *te,
+static void finished_handler(struct event_context *ev_ctx, struct timed_event *te,
-			  struct timeval tval, void *private)
+			     struct timeval tval, void *private)
 {
-	torture_comment(test, "timed_handler called[%d]\n", te_count);
+	int *finished = private;
-	if (te_count > 2) {
+	(*finished) = 1;
-		close(write_fd);
-		write_fd = -1;
-	}
-	if (te_count > 5) {
-		torture_comment(test, "remove fd event!\n");
-		talloc_free(fde);
-		fde = NULL;
-		return;
-	}
-	te_count++;
-	event_add_timed(ev_ctx, ev_ctx, timeval_current_ofs(0,500), timed_handler, private);
 }
 
-static bool test_event_context(struct torture_context *torture_ctx,
+static void count_handler(struct event_context *ev_ctx, struct signal_event *te,
-							   const void *test_data)
+			  int signum, int count, void *info, void *private)
+{
+	int *countp = private;
+	(*countp) += count;
+}
+
+static bool test_event_context(struct torture_context *test,
+			       const void *test_data)
 {
 	struct event_context *ev_ctx;
 	int fd[2] = { -1, -1 };
 	const char *backend = (const char *)test_data;
-	TALLOC_CTX *mem_ctx = torture_ctx;
+	int alarm_count=0, info_count=0;
+	struct fd_event *fde;
+	struct signal_event *se1, *se2, *se3;
+	int finished=0;
+	struct timeval t;
+	char c = 0;
 
-	test = torture_ctx;
+	ev_ctx = event_context_init_byname(test, backend);
-
-	ev_ctx = event_context_init_byname(mem_ctx, backend);
 	if (ev_ctx == NULL) {
 		torture_comment(test, "event backend '%s' not supported\n", backend);
 		return true;
@@ -90,29 +77,51 @@ static bool test_event_context(struct torture_context *torture_ctx,
 	torture_comment(test, "Testing event backend '%s'\n", backend);
 
 	/* reset globals */
-	write_fd = -1;
-	read_fd = -1;
-	fde = NULL;
-	te_count = 0;
 	fde_count = 0;
 
 	/* create a pipe */
 	pipe(fd);
-	read_fd = fd[0];
-	write_fd = fd[1];
 
-	fde = event_add_fd(ev_ctx, ev_ctx, read_fd, EVENT_FD_READ, 
+	fde = event_add_fd(ev_ctx, ev_ctx, fd[0], EVENT_FD_READ, 
-			   fde_handler, &read_fd);
+			   fde_handler, fd);
 
-	event_add_timed(ev_ctx, ev_ctx, timeval_current_ofs(0,500), 
+	event_add_timed(ev_ctx, ev_ctx, timeval_current_ofs(2,0), 
-			timed_handler, fde);
+			finished_handler, &finished);
 
-	event_loop_wait(ev_ctx);
+	se1 = event_add_signal(ev_ctx, ev_ctx, SIGALRM, SA_RESTART, count_handler, &alarm_count);
+	se2 = event_add_signal(ev_ctx, ev_ctx, SIGALRM, SA_RESETHAND, count_handler, &alarm_count);
+#ifdef SA_SIGINFO
+	se3 = event_add_signal(ev_ctx, ev_ctx, SIGUSR1, SA_SIGINFO, count_handler, &info_count);
+#endif
+
+	write(fd[1], &c, 1);
+
+	t = timeval_current();
+	while (!finished) {
+		event_loop_once(ev_ctx);
+	}
+
+	talloc_free(fde);
+	close(fd[0]);
+	close(fd[1]);
+
+	while (alarm_count < fde_count+1) {
+		event_loop_once(ev_ctx);
+	}
+
+	torture_comment(test, "Got %.2f pipe events/sec\n", fde_count/timeval_elapsed(&t));
+
+	talloc_free(se1);
+
+	torture_assert_int_equal(test, alarm_count, 1+fde_count, "alarm count mismatch");
+
+#ifdef SA_SIGINFO
+	talloc_free(se3);
+	torture_assert_int_equal(test, info_count, fde_count, "info count mismatch");
+#endif
 
-	close(read_fd);
-	close(write_fd);
-	
 	talloc_free(ev_ctx);
+
 	return true;
 }