From 42397cb51260066aa14c2c744d41a75ccbedb190 Mon Sep 17 00:00:00 2001
From: Stefan Kalkowski <stefan.kalkowski@genode-labs.com>
Date: Wed, 18 Jun 2014 15:04:30 +0200
Subject: [PATCH] os: avoid deadlock in packet stream (fix #1186)

Respectively resend a packet-stream-not-empty signal when a new signal handler
gets registered.
---
 repos/base/include/base/signal.h     |  7 +++++++
 repos/base/src/base/signal/common.cc |  2 ++
 repos/os/include/os/packet_stream.h  | 16 ++++++++++++++++
 3 files changed, 25 insertions(+)

diff --git a/repos/base/include/base/signal.h b/repos/base/include/base/signal.h
index 55ce6f473..acd3e1cd9 100644
--- a/repos/base/include/base/signal.h
+++ b/repos/base/include/base/signal.h
@@ -132,6 +132,13 @@ namespace Genode {
 			 */
 			void context(Signal_context_capability context);
 
+
+			/**
+			 * Return signal context
+			 */
+			Signal_context_capability context();
+
+
 			/**
 			 * Trigger signal submission to context
 			 *
diff --git a/repos/base/src/base/signal/common.cc b/repos/base/src/base/signal/common.cc
index 02d9abf42..7de4ebe65 100644
--- a/repos/base/src/base/signal/common.cc
+++ b/repos/base/src/base/signal/common.cc
@@ -78,6 +78,8 @@ Signal_transmitter::Signal_transmitter(Signal_context_capability context)
 void Signal_transmitter::context(Signal_context_capability context) {
 	_context = context; }
 
+Signal_context_capability Signal_transmitter::context() { return _context; }
+
 
 /*********************
  ** Signal_receiver **
diff --git a/repos/os/include/os/packet_stream.h b/repos/os/include/os/packet_stream.h
index 03c57c880..61dd7b51c 100644
--- a/repos/os/include/os/packet_stream.h
+++ b/repos/os/include/os/packet_stream.h
@@ -260,6 +260,14 @@ class Packet_descriptor_transmitter
 		void register_rx_ready_cap(Genode::Signal_context_capability cap)
 		{
 			_rx_ready.context(cap);
+
+			/*
+			 * if a packet was already put into the queue
+			 * before a signal handler was registered,
+			 * a signal has to be send again
+			 */
+			if (!_tx_queue->empty())
+				_rx_ready.submit();
 		}
 
 		bool ready_for_tx()
@@ -341,6 +349,14 @@ class Packet_descriptor_receiver
 		void register_tx_ready_cap(Genode::Signal_context_capability cap)
 		{
 			_tx_ready.context(cap);
+
+			/*
+			 * if a packet was already put into the queue
+			 * before a signal handler was registered,
+			 * a signal has to be send again
+			 */
+			if (!_rx_queue->empty())
+				_tx_ready.submit();
 		}
 
 		bool ready_for_rx()