From: Nick Mathewson <nickm@torproject.org>
Date: Tue, 27 Oct 2009 04:25:45 +0000 (+0000)
Subject: Give event_assign a return value, and make it less inclined to exit().
X-Git-Tag: release-2.0.3-alpha~75
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e9ee1057e63b33d833b83b404232a0ccde34ae56;p=libevent

Give event_assign a return value, and make it less inclined to exit().

We also refactor event_assign so that it is the core function, and
event_set() is only the wrapper.

svn:r1469
---

diff --git a/ChangeLog b/ChangeLog
index 878ac8fe..cef1fda7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -34,6 +34,7 @@ Changes in 2.0.3-alpha:
  o Stop using enums as arguments or return values when what we mean is a bitfield of enum values.  C++ doesn't believe that you can OR two enum values together and get another enum, and C++ takes its typing seriously.  Patch from Christopher Davis.
  o Add an API to replace all fatal calls to exit() with a user-provided panic function.
  o Replace all assert() calls with a variant that is aware of the user-provided logging and panic functions.
+ o Add a return value to event_assign so that it can fail rather than asserting when the user gives it bad input.  event_set still dies on bad input.
 
 
 Changes in 2.0.2-alpha:
diff --git a/event.c b/event.c
index c484c758..d82c7c6e 100644
--- a/event.c
+++ b/event.c
@@ -1038,9 +1038,8 @@ event_base_once(struct event_base *base, evutil_socket_t fd, short events,
 	return (0);
 }
 
-void
-event_set(struct event *ev, evutil_socket_t fd, short events,
-	  void (*callback)(evutil_socket_t, short, void *), void *arg)
+int
+event_assign(struct event *ev, struct event_base *base, evutil_socket_t fd, short events, void (*callback)(evutil_socket_t, short, void *), void *arg)
 {
 	/* Take the current base - caller needs to set the real base later */
 	ev->ev_base = current_base;
@@ -1055,9 +1054,11 @@ event_set(struct event *ev, evutil_socket_t fd, short events,
 	ev->ev_pncalls = NULL;
 
 	if (events & EV_SIGNAL) {
-		if ((events & (EV_READ|EV_WRITE)) != 0)
-			event_errx(1, "%s: EV_SIGNAL incompatible use",
-			    __func__);
+		if ((events & (EV_READ|EV_WRITE)) != 0) {
+			event_warnx("%s: EV_SIGNAL is not compatible with "
+			    "EV_READ or EV_WRITE", __func__);
+			return -1;
+		}
 		ev->ev_closure = EV_CLOSURE_SIGNAL;
 	} else {
 		if (events & EV_PERSIST) {
@@ -1070,9 +1071,16 @@ event_set(struct event *ev, evutil_socket_t fd, short events,
 
 	min_heap_elem_init(ev);
 
-	/* by default, we put new events into the middle priority */
-	if (current_base)
-		ev->ev_pri = current_base->nactivequeues/2;
+	if (base != NULL) {
+		if (event_base_set(base, ev) < 0) {
+			event_warnx("%s: event_base_set() failed", __func__);
+			return -1;
+		}
+	} else if (current_base) {
+		/* by default, we put new events into the middle priority */
+			ev->ev_pri = current_base->nactivequeues/2;
+	}
+	return 0;
 }
 
 int
@@ -1089,11 +1097,12 @@ event_base_set(struct event_base *base, struct event *ev)
 }
 
 void
-event_assign(struct event *ev, struct event_base *base, evutil_socket_t fd, short events, void (*cb)(evutil_socket_t, short, void *), void *arg)
+event_set(struct event *ev, evutil_socket_t fd, short events,
+	  void (*callback)(evutil_socket_t, short, void *), void *arg)
 {
-	event_set(ev, fd, events, cb, arg);
-	if (base != NULL)
-		EVUTIL_ASSERT(event_base_set(base, ev) == 0);
+	int r;
+	r = event_assign(ev, NULL, fd, events, callback, arg);
+       	EVUTIL_ASSERT(r == 0);
 }
 
 struct event *
@@ -1103,7 +1112,10 @@ event_new(struct event_base *base, evutil_socket_t fd, short events, void (*cb)(
 	ev = mm_malloc(sizeof(struct event));
 	if (ev == NULL)
 		return (NULL);
-	event_assign(ev, base, fd, events, cb, arg);
+	if (event_assign(ev, base, fd, events, cb, arg) < 0) {
+		mm_free(ev);
+		return (NULL);
+	}
 
 	return (ev);
 }
diff --git a/include/event2/event.h b/include/event2/event.h
index 27ca6ba8..5358e9d3 100644
--- a/include/event2/event.h
+++ b/include/event2/event.h
@@ -422,10 +422,12 @@ int event_base_got_break(struct event_base *);
   @param fn callback function to be invoked when the event occurs
   @param arg an argument to be passed to the callback function
 
+  @return 0 if success, or -1 on invalid arguments.
+
   @see event_add(), event_del(), event_once()
 
   */
-void event_assign(struct event *, struct event_base *, evutil_socket_t, short, void (*)(evutil_socket_t, short, void *), void *);
+int event_assign(struct event *, struct event_base *, evutil_socket_t, short, void (*)(evutil_socket_t, short, void *), void *);
 
 /**
   Create and allocate a new event structure, ready to be added.
diff --git a/test/regress.c b/test/regress.c
index dce50d6f..eef9859b 100644
--- a/test/regress.c
+++ b/test/regress.c
@@ -986,6 +986,19 @@ end:
 	event_del(&ev1);
 }
 
+static void
+test_bad_assign(void *ptr)
+{
+	struct event ev;
+	int r;
+	/* READ|SIGNAL is not allowed */
+	r = event_assign(&ev, NULL, -1, EV_SIGNAL|EV_READ, dummy_read_cb, NULL);
+	tt_int_op(r,==,-1);
+
+end:
+	;
+}
+
 static void
 test_event_base_new(void *ptr)
 {
@@ -1784,6 +1797,8 @@ struct testcase_t main_testcases[] = {
 
 	BASIC(manipulate_active_events, TT_FORK|TT_NEED_BASE),
 
+	BASIC(bad_assign, TT_FORK|TT_NEED_BASE|TT_NO_LOGS),
+
         /* These are still using the old API */
         LEGACY(persistent_timeout, TT_FORK|TT_NEED_BASE),
         LEGACY(priorities, TT_FORK|TT_NEED_BASE),