fix for crashes when stopping or restarting DHT

include/libtorrent/aux_/session_impl.hpp

@@ -363,7 +363,7 @@ namespace libtorrent
 			boost::posix_time::ptime m_last_tick;
 
 #ifndef TORRENT_DISABLE_DHT
-			boost::scoped_ptr<dht::dht_tracker> m_dht;
+			boost::shared_ptr<dht::dht_tracker> m_dht;
 			dht_settings m_dht_settings;
 #endif
 			// the timer used to fire the second_tick

include/libtorrent/kademlia/dht_tracker.hpp

@@ -45,6 +45,8 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <boost/optional.hpp>
 #include <boost/lexical_cast.hpp>
 #include <boost/filesystem/operations.hpp>
+#include <boost/intrusive_ptr.hpp>
+#include <boost/detail/atomic_count.hpp>
 
 #include "libtorrent/kademlia/node.hpp"
 #include "libtorrent/kademlia/node_id.hpp"
@@ -60,10 +62,18 @@ namespace libtorrent { namespace dht
 	TORRENT_DECLARE_LOG(dht_tracker);
 #endif
 
+	struct dht_tracker;
+
+	TORRENT_EXPORT void intrusive_ptr_add_ref(dht_tracker const*);
+	TORRENT_EXPORT void intrusive_ptr_release(dht_tracker const*);	
+
 	struct dht_tracker
 	{
+		friend void intrusive_ptr_add_ref(dht_tracker const*);
+		friend void intrusive_ptr_release(dht_tracker const*);
 		dht_tracker(asio::io_service& ios, dht_settings const& settings
 			, asio::ip::address listen_interface, entry const& bootstrap);
+		void stop();
 
 		void add_node(udp::endpoint node);
 		void add_node(std::pair<std::string, int> const& node);
@@ -80,6 +90,9 @@ namespace libtorrent { namespace dht
 		void dht_status(session_status& s);
 
 	private:
+	
+		boost::intrusive_ptr<dht_tracker> self()
+		{ return boost::intrusive_ptr<dht_tracker>(this); }
 
 		void on_name_lookup(asio::error_code const& e
 			, udp::resolver::iterator host);
@@ -116,6 +129,9 @@ namespace libtorrent { namespace dht
 
 		// used to resolve hostnames for nodes
 		udp::resolver m_host_resolver;
+		
+		// reference counter for intrusive_ptr
+		mutable boost::detail::atomic_count m_refs;
 
 #ifdef TORRENT_DHT_VERBOSE_LOGGING
 		int m_replies_sent[5];

src/kademlia/dht_tracker.cpp

@@ -126,6 +126,22 @@ namespace
 
 namespace libtorrent { namespace dht
 {
+
+	void intrusive_ptr_add_ref(dht_tracker const* c)
+	{
+		assert(c->m_refs >= 0);
+		assert(c != 0);
+		++c->m_refs;
+	}
+
+	void intrusive_ptr_release(dht_tracker const* c)
+	{
+		assert(c->m_refs > 0);
+		assert(c != 0);
+		if (--c->m_refs == 0)
+			delete c;
+	}
+
 #ifdef TORRENT_DHT_VERBOSE_LOGGING
 	TORRENT_DEFINE_LOG(dht_tracker)
 #endif
@@ -146,6 +162,7 @@ namespace libtorrent { namespace dht
 		, m_settings(settings)
 		, m_refresh_bucket(160)
 		, m_host_resolver(ios)
+		, m_refs(0)
 	{
 		using boost::bind;
 
@@ -187,20 +204,28 @@ namespace libtorrent { namespace dht
 			} catch (std::exception&) {}
 		}
 
-		m_dht.bootstrap(initial_nodes, bind(&dht_tracker::on_bootstrap, this));
+		m_dht.bootstrap(initial_nodes, bind(&dht_tracker::on_bootstrap, self()));
 
 		m_socket.async_receive_from(asio::buffer(&m_in_buf[m_buffer][0]
 			, m_in_buf[m_buffer].size()), m_remote_endpoint[m_buffer]
-			, m_strand.wrap(bind(&dht_tracker::on_receive, this, _1, _2)));
+			, m_strand.wrap(bind(&dht_tracker::on_receive, self(), _1, _2)));
 		m_timer.expires_from_now(seconds(1));
-		m_timer.async_wait(m_strand.wrap(bind(&dht_tracker::tick, this, _1)));
+		m_timer.async_wait(m_strand.wrap(bind(&dht_tracker::tick, self(), _1)));
 
 		m_connection_timer.expires_from_now(seconds(10));
 		m_connection_timer.async_wait(m_strand.wrap(
-			bind(&dht_tracker::connection_timeout, this, _1)));
+			bind(&dht_tracker::connection_timeout, self(), _1)));
 
 		m_refresh_timer.expires_from_now(minutes(15));
-		m_refresh_timer.async_wait(m_strand.wrap(bind(&dht_tracker::refresh_timeout, this, _1)));
+		m_refresh_timer.async_wait(m_strand.wrap(bind(&dht_tracker::refresh_timeout, self(), _1)));
+	}
+
+	void dht_tracker::stop()
+	{
+		m_timer.cancel();
+		m_connection_timer.cancel();
+		m_refresh_timer.cancel();
+		m_socket.close();
 	}
 
 	void dht_tracker::dht_status(session_status& s)
@@ -215,7 +240,7 @@ namespace libtorrent { namespace dht
 		if (e) return;
 		time_duration d = m_dht.connection_timeout();
 		m_connection_timer.expires_from_now(d);
-		m_connection_timer.async_wait(m_strand.wrap(bind(&dht_tracker::connection_timeout, this, _1)));
+		m_connection_timer.async_wait(m_strand.wrap(bind(&dht_tracker::connection_timeout, self(), _1)));
 	}
 	catch (std::exception& exc)
 	{
@@ -233,7 +258,7 @@ namespace libtorrent { namespace dht
 		time_duration d = m_dht.refresh_timeout();
 		m_refresh_timer.expires_from_now(d);
 		m_refresh_timer.async_wait(m_strand.wrap(
-			bind(&dht_tracker::refresh_timeout, this, _1)));
+			bind(&dht_tracker::refresh_timeout, self(), _1)));
 	}
 	catch (std::exception&)
 	{
@@ -361,7 +386,7 @@ namespace libtorrent { namespace dht
 		m_buffer = (m_buffer + 1) & 1;
 		m_socket.async_receive_from(asio::buffer(&m_in_buf[m_buffer][0]
 			, m_in_buf[m_buffer].size()), m_remote_endpoint[m_buffer]
-			, m_strand.wrap(bind(&dht_tracker::on_receive, this, _1, _2)));
+			, m_strand.wrap(bind(&dht_tracker::on_receive, self(), _1, _2)));
 
 		if (error) return;
 
@@ -655,7 +680,7 @@ namespace libtorrent { namespace dht
 	{
 		udp::resolver::query q(node.first, lexical_cast<std::string>(node.second));
 		m_host_resolver.async_resolve(q, m_strand.wrap(
-			bind(&dht_tracker::on_name_lookup, this, _1, _2)));
+			bind(&dht_tracker::on_name_lookup, self(), _1, _2)));
 	}
 
 	void dht_tracker::on_name_lookup(asio::error_code const& e
@@ -673,7 +698,7 @@ namespace libtorrent { namespace dht
 	{
 		udp::resolver::query q(node.first, lexical_cast<std::string>(node.second));
 		m_host_resolver.async_resolve(q, m_strand.wrap(
-			bind(&dht_tracker::on_router_name_lookup, this, _1, _2)));
+			bind(&dht_tracker::on_router_name_lookup, self(), _1, _2)));
 	}
 
 	void dht_tracker::on_router_name_lookup(asio::error_code const& e

src/session_impl.cpp

@@ -1507,7 +1507,11 @@ namespace libtorrent { namespace detail
 	void session_impl::start_dht(entry const& startup_state)
 	{
 		mutex_t::scoped_lock l(m_mutex);
-		m_dht.reset();
+		if (m_dht)
+		{
+			m_dht->stop();
+			m_dht.reset();
+		}
 		m_dht.reset(new dht::dht_tracker(m_io_service
 			, m_dht_settings, m_listen_interface.address()
 			, startup_state));
@@ -1516,6 +1520,7 @@ namespace libtorrent { namespace detail
 	void session_impl::stop_dht()
 	{
 		mutex_t::scoped_lock l(m_mutex);
+		m_dht->stop();
 		m_dht.reset();
 	}
 

src/storage.cpp

@@ -420,9 +420,11 @@ namespace libtorrent
 		if (m_pimpl->info.num_files() == 1)
 		{
 			path single_file = m_pimpl->info.begin_files()->path;
+			assert(!is_complete(single_file));
 			if (single_file.has_branch_path())
 			{
-				std::string const& trunk = *single_file.begin();
+				assert(single_file.begin() != single_file.end());
+				std::string trunk = *single_file.begin();
 				old_path = m_pimpl->save_path / trunk;
 				new_path = save_path / trunk;
 			}