From: Martin Willi <martin@revosec.ch>
Date: Tue, 2 Jul 2013 12:09:45 +0000 (+0200)
Subject: stream: allow async read/write callback to destroy the stream explicitly
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f3390cd3e74f79576c96d199fe9d7daa25c5cfd7;p=thirdparty%2Fstrongswan.git

stream: allow async read/write callback to destroy the stream explicitly
---

diff --git a/src/libstrongswan/networking/streams/stream.c b/src/libstrongswan/networking/streams/stream.c
index 20379fb415..b3dd7680b2 100644
--- a/src/libstrongswan/networking/streams/stream.c
+++ b/src/libstrongswan/networking/streams/stream.c
@@ -175,21 +175,26 @@ static void remove_watcher(private_stream_t *this)
 static bool watch(private_stream_t *this, int fd, watcher_event_t event)
 {
 	bool keep = FALSE;
+	stream_cb_t cb;
 
 	switch (event)
 	{
 		case WATCHER_READ:
-			keep = this->read_cb(this->read_data, &this->public);
-			if (!keep)
+			cb = this->read_cb;
+			this->read_cb = NULL;
+			keep = cb(this->read_data, &this->public);
+			if (keep)
 			{
-				this->read_cb = NULL;
+				this->read_cb = cb;
 			}
 			break;
 		case WATCHER_WRITE:
-			keep = this->write_cb(this->write_data, &this->public);
-			if (!keep)
+			cb = this->write_cb;
+			this->write_cb = NULL;
+			keep = cb(this->write_data, &this->public);
+			if (keep)
 			{
-				this->write_cb = NULL;
+				this->write_cb = cb;
 			}
 			break;
 		case WATCHER_EXCEPT:
diff --git a/src/libstrongswan/networking/streams/stream.h b/src/libstrongswan/networking/streams/stream.h
index 8cd8419c30..810514da96 100644
--- a/src/libstrongswan/networking/streams/stream.h
+++ b/src/libstrongswan/networking/streams/stream.h
@@ -39,9 +39,9 @@ typedef stream_t*(*stream_constructor_t)(char *uri);
 /**
  * Callback function prototype, called when stream is ready.
  *
- * It is not allowed to destroy the stream during the callback, this would
- * deadlock. Instead, return FALSE to destroy the stream. It is not allowed
- * to call on_read()/on_write() during this callback.
+ * It is allowed to destroy the stream during the callback, but only if it has
+ * no other active on_read()/on_write() callback and returns FALSE. It is not
+ * allowed to to call on_read()/on_write/() during the callback.
  *
  * As select() may return even if a read()/write() would actually block, it is
  * recommended to use the non-blocking calls and handle return values
@@ -49,7 +49,7 @@ typedef stream_t*(*stream_constructor_t)(char *uri);
  *
  * @param data			data passed during callback registration
  * @param stream		associated stream
- * @return				FALSE to destroy the stream
+ * @return				FALSE unregisters the invoked callback, TRUE keeps it
  */
 typedef bool (*stream_cb_t)(void *data, stream_t *stream);