attempted to fix deadlock caused by ipc logger causing recursion.

src/gui/src/IpcClient.cpp

@@ -62,12 +62,14 @@ void IpcClient::read()
 				char lenBuf[2];
 				stream.readRawData(lenBuf, 2);
 				int len = bytesToInt(lenBuf, 2);
-				std::cout << "len: " << len << std::endl;
+				std::cout << "told len: " << len << std::endl;
 
 				char* data = new char[len];
 				stream.readRawData(data, len);
 
-				readLogLine(QString::fromUtf8(data, len));
+				QString line = QString::fromUtf8(data, len);
+				std::cout << "actual len: " << line.size() << std::endl;
+				readLogLine(line);
 				break;
 			}
 

src/lib/ipc/CIpcClientProxy.cpp

@@ -22,6 +22,7 @@
 #include "CLog.h"
 #include "CIpcMessage.h"
 #include "CProtocolUtil.h"
+#include "CArch.h"
 
 CEvent::Type			CIpcClientProxy::s_messageReceivedEvent = CEvent::kUnknown;
 CEvent::Type			CIpcClientProxy::s_disconnectedEvent = CEvent::kUnknown;
@@ -30,13 +31,21 @@ CIpcClientProxy::CIpcClientProxy(synergy::IStream& stream) :
 m_stream(stream),
 m_enableLog(false),
 m_clientType(kIpcClientUnknown),
-m_disconnecting(false)
+m_disconnecting(false),
+m_socketBusy(false)
 {
+	m_mutex = ARCH->newMutex();
+
 	EVENTQUEUE->adoptHandler(
 		m_stream.getInputReadyEvent(), stream.getEventTarget(),
 		new TMethodEventJob<CIpcClientProxy>(
 		this, &CIpcClientProxy::handleData));
 
+	EVENTQUEUE->adoptHandler(
+		m_stream.getOutputErrorEvent(), stream.getEventTarget(),
+		new TMethodEventJob<CIpcClientProxy>(
+		this, &CIpcClientProxy::handleWriteError));
+
 	EVENTQUEUE->adoptHandler(
 		m_stream.getInputShutdownEvent(), stream.getEventTarget(),
 		new TMethodEventJob<CIpcClientProxy>(
@@ -52,6 +61,8 @@ CIpcClientProxy::~CIpcClientProxy()
 {
 	EVENTQUEUE->removeHandler(
 		m_stream.getInputReadyEvent(), m_stream.getEventTarget());
+	EVENTQUEUE->removeHandler(
+		m_stream.getOutputErrorEvent(), m_stream.getEventTarget());
 	EVENTQUEUE->removeHandler(
 		m_stream.getInputShutdownEvent(), m_stream.getEventTarget());
 	EVENTQUEUE->removeHandler(
@@ -77,6 +88,12 @@ CIpcClientProxy::handleWriteError(const CEvent&, void*)
 void
 CIpcClientProxy::handleData(const CEvent&, void*)
 {
+	// ugh, not sure if this is needed here. the write function has it to protect
+	// m_socketBusy (for dropping log messages primarily). but i think i saw a
+	// deadlock even after adding this mechanism. my rationale here is that i don't
+	// want the read to deadlock the stream (if that's even possible).
+	CArchMutexLock lock(m_mutex);
+
 	UInt8 code[1];
 	UInt32 n = m_stream.read(code, 1);
 	while (n != 0) {
@@ -115,35 +132,52 @@ CIpcClientProxy::handleData(const CEvent&, void*)
 void
 CIpcClientProxy::send(const CIpcMessage& message)
 {
-	if (m_enableLog) {
-		LOG((CLOG_DEBUG "ipc client proxy write: %d", message.m_type));
+	// discard message if we're busy writing already. this is to prevent
+	// deadlock, since this function can sometimes generate log messages
+	// through stream usage.
+	if (m_socketBusy) {
+		return;
 	}
 
-	UInt8 code[1];
-	code[0] = message.m_type;
-	m_stream.write(code, 1);
-
-	switch (message.m_type) {
-	case kIpcLogLine: {
-		CString* s = (CString*)message.m_data;
-		const char* data = s->c_str();
-		
-		int len = strlen(data);
-		CProtocolUtil::writef(&m_stream, "%2i", len);
-
-		m_stream.write(data, len);
-		break;
-	}
-			
-	case kIpcShutdown:
-		// no data.
-		break;
-
-	default:
+	CArchMutexLock lock(m_mutex);
+	m_socketBusy = true;
+	try {
 		if (m_enableLog) {
-			LOG((CLOG_ERR "message not supported: %d", message.m_type));
+			LOG((CLOG_DEBUG "ipc client proxy write: %d", message.m_type));
 		}
-		break;
+
+		UInt8 code[1];
+		code[0] = message.m_type;
+		m_stream.write(code, 1);
+
+		switch (message.m_type) {
+		case kIpcLogLine: {
+			CString* s = (CString*)message.m_data;
+			const char* data = s->c_str();
+		
+			int len = strlen(data);
+			CProtocolUtil::writef(&m_stream, "%2i", len);
+
+			m_stream.write(data, len);
+			break;
+		}
+			
+		case kIpcShutdown:
+			// no data.
+			break;
+
+		default:
+			if (m_enableLog) {
+				LOG((CLOG_ERR "message not supported: %d", message.m_type));
+			}
+			break;
+		}
+		
+		m_socketBusy = false;
+	}
+	catch (...) {
+		m_socketBusy = false;
+		throw;
 	}
 }
 

src/lib/ipc/CIpcClientProxy.h

@@ -19,6 +19,7 @@
 
 #include "CEvent.h"
 #include "Ipc.h"
+#include "CMutex.h"
 
 namespace synergy { class IStream; }
 class CIpcMessage;
@@ -50,8 +51,11 @@ public:
 	bool				m_enableLog;
 	EIpcClientType		m_clientType;
 	bool				m_disconnecting;
+	bool				m_socketBusy;
 	
 private:
+	CArchMutex			m_mutex;
+
 	static CEvent::Type	s_messageReceivedEvent;
 	static CEvent::Type	s_disconnectedEvent;
 };

src/lib/synergy/CDaemonApp.cpp

@@ -297,13 +297,31 @@ CDaemonApp::handleIpcMessage(const CEvent& e, void*)
 			CString& command = *static_cast<CString*>(m.m_data);
 			LOG((CLOG_DEBUG "got new command: %s", command.c_str()));
 
+			CString debugArg("--debug");
+			int debugArgPos = command.find(debugArg);
+			if (debugArgPos != CString::npos) {
+				int from = debugArgPos + debugArg.size() + 1;
+				int nextSpace = command.find(" ", from);
+				CString logLevel(command.substr(from, nextSpace - from));
+				
+				try {
+					// change log level based on that in the command string
+					// and change to that log level now.
+					ARCH->setting("LogLevel", logLevel);
+					CLOG->setFilter(logLevel.c_str());
+				}
+				catch (XArch& e) {
+					LOG((CLOG_ERR "failed to save LogLevel setting, %s", e.what().c_str()));
+				}
+			}
+
 			try {
 				// store command in system settings. this is used when the daemon
 				// next starts.
 				ARCH->setting("Command", command);
 			}
 			catch (XArch& e) {
-				LOG((CLOG_ERR "failed to save setting, %s", e.what().c_str()));
+				LOG((CLOG_ERR "failed to save Command setting, %s", e.what().c_str()));
 			}
 				
 			// tell the relauncher about the new command. this causes the