Set timeouts on the socket so we don't hang forever if something bad happens.

Don't set keepalive if it's not requested.

external/Mono.Debugger.Soft/Mono.Debugger.Soft/Connection.cs

@@ -1049,6 +1049,8 @@ namespace Mono.Debugger.Soft
 			while (offset < len) {
 				int n = TransportReceive (buf, buf_offset + offset, len - offset);
 
+				if (n < 0)
+					return n;
 				if (n == 0)
 					return offset;
 				offset += n;
@@ -1105,6 +1107,8 @@ namespace Mono.Debugger.Soft
 			byte[] header = new byte [HEADER_LENGTH];
 
 			int len = Receive (header, 0, header.Length);
+			if (len < 0)
+				return null;
 			if (len == 0)
 				return new byte [0];
 			if (len != HEADER_LENGTH) {
@@ -1173,6 +1177,9 @@ namespace Mono.Debugger.Soft
 		bool ReceivePacket () {
 				byte[] packet = ReadPacket ();
 
+				if (packet == null)
+					return true;
+
 				if (packet.Length == 0) {
 					return false;
 				}
@@ -1635,7 +1642,8 @@ namespace Mono.Debugger.Soft
 		internal void SetSocketTimeouts (int send_timeout, int receive_timeout, int keepalive_interval)
 		{
 			TransportSetTimeouts (send_timeout, receive_timeout);
-			SendReceive (CommandSet.VM, (int)CmdVM.SET_KEEPALIVE, new PacketWriter ().WriteId (keepalive_interval));
+			if (keepalive_interval > 0)
+				SendReceive (CommandSet.VM, (int)CmdVM.SET_KEEPALIVE, new PacketWriter ().WriteId (keepalive_interval));
 		}
 
 		internal long[] VM_GetTypesForSourceFile (string fname, bool ignoreCase) {
@@ -2340,7 +2348,13 @@ namespace Mono.Debugger.Soft
 		
 		protected override int TransportReceive (byte[] buf, int buf_offset, int len)
 		{
-			return socket.Receive (buf, buf_offset, len, SocketFlags.None);
+			try {
+				return socket.Receive (buf, buf_offset, len, SocketFlags.None);
+			} catch (SocketException ex) {
+				if (ex.ErrorCode == (int)SocketError.TimedOut)
+					return -1;
+				throw;
+			}
 		}
 		
 		protected override void TransportSetTimeouts (int send_timeout, int receive_timeout)

external/Mono.Debugger.Soft/Mono.Debugger.Soft/VirtualMachineManager.cs

@@ -35,6 +35,8 @@ namespace Mono.Debugger.Soft
 		private delegate VirtualMachine ListenCallback (Socket dbg_sock, Socket con_sock); 
 		private delegate VirtualMachine ConnectCallback (Socket dbg_sock, Socket con_sock, IPEndPoint dbg_ep, IPEndPoint con_ep); 
 
+		public static int DefaultTimeout { get; set; }
+
 		internal VirtualMachineManager () {
 		}
 
@@ -328,6 +330,8 @@ namespace Mono.Debugger.Soft
 			
 			vm.StandardOutput = standardOutput;
 			vm.StandardError = standardError;
+			if (DefaultTimeout > 0)
+				vm.SetSocketTimeouts (DefaultTimeout, DefaultTimeout, 0);
 			
 			transport.EventHandler = new EventHandler (vm);
 

src/Debugger/Backend.Sdb/VirtualMachine.cs

@@ -97,6 +97,7 @@ namespace Debugger.Backend.Sdb
 		public void Attach (int port)
 		{
 			LogProvider.Log ("Attempting connection at port {0}...", port);
+			MDS.VirtualMachineManager.DefaultTimeout = 500;
 			vm = MDS.VirtualMachineManager.Connect (new IPEndPoint (IPAddress.Loopback, port));
 			vm.EnableEvents (
 				MDS.EventType.AppDomainCreate,