[Dovecot] imap-zlib patch to fix runaway imap process

[Mike Abbott]

Here is a patch to fix the problem where an imap process runs away when imap-zlib is in use.  The backtrace showed:

io_loop_handler_run ->
stream_send_io ->
client_output ->
o_stream_flush ->
o_stream_zlib_flush ->
o_stream_zlib_send_flush

When o_stream_zlib_flush returns 0, stream_send_io reinstates the IO_WRITE event, causing the infinite loop.

diff -ur dovecot-2.0.beta4/src/plugins/zlib/ostream-bzlib.c dovecot-2.0.beta4+fix/src/plugins/zlib/ostream-bzlib.c
--- dovecot-2.0.beta4/src/plugins/zlib/ostream-bzlib.c	2010-02-12 20:22:07.000000000 -0600
+++ dovecot-2.0.beta4+fix/src/plugins/zlib/ostream-bzlib.c	2010-04-20 19:15:29.000000000 -0500
@@ -122,15 +122,15 @@
 static int o_stream_bzlib_flush(struct ostream_private *stream)
 {
 	struct bzlib_ostream *zstream = (struct bzlib_ostream *)stream;
+	int ret;
 
 	if (o_stream_bzlib_send_flush(zstream) < 0)
 		return -1;
 
-	if (o_stream_flush(zstream->output) < 0) {
+	ret = o_stream_flush(zstream->output);
+	if (ret < 0)
 		zstream_copy_error(zstream);
-		return -1;
-	}
-	return 0;
+	return ret;
 }
 
 static ssize_t
diff -ur dovecot-2.0.beta4/src/plugins/zlib/ostream-zlib.c dovecot-2.0.beta4+fix/src/plugins/zlib/ostream-zlib.c
--- dovecot-2.0.beta4/src/plugins/zlib/ostream-zlib.c	2010-02-18 22:01:56.000000000 -0600
+++ dovecot-2.0.beta4+fix/src/plugins/zlib/ostream-zlib.c	2010-04-20 19:15:29.000000000 -0500
@@ -184,15 +184,15 @@
 static int o_stream_zlib_flush(struct ostream_private *stream)
 {
 	struct zlib_ostream *zstream = (struct zlib_ostream *)stream;
+	int ret;
 
 	if (o_stream_zlib_send_flush(zstream) < 0)
 		return -1;
 
-	if (o_stream_flush(zstream->output) < 0) {
+	ret = o_stream_flush(zstream->output);
+	if (ret < 0)
 		zstream_copy_error(zstream);
-		return -1;
-	}
-	return 0;
+	return ret;
 }
 
 static ssize_t