Add thread signal handling

Send SIGUSR2 to interrupt xmlrpc and arq_socket threads
Restore the default signal disposition for various signals
handled by xmlrpc-c's abyss server

src/include/main.h

@@ -48,6 +48,7 @@ extern void			arq_init();
 extern void			arq_close();
 extern void			WriteARQ(unsigned int);
 extern void			checkTLF();
+void 				setup_signal_handlers(void);
 
 #define ARQBUFSIZ 8192
 

src/main.cxx

@@ -124,7 +124,6 @@ void debug_exec(char** argv);
 void set_platform_ui(void);
 double speed_test(int converter, unsigned repeat);
 
-
 int main(int argc, char ** argv)
 {
 	appname = argv[0];
@@ -139,11 +138,7 @@ int main(int argc, char ** argv)
 
 	set_unexpected(handle_unexpected);
 	set_terminate(diediedie);
-	signal(SIGSEGV, handle_signal);
-	signal(SIGILL, handle_signal);
-	signal(SIGABRT, handle_signal);
-	signal(SIGCHLD, SIG_IGN);
-	signal(SIGPIPE, SIG_IGN);
+	setup_signal_handlers();
 
 	setlocale(LC_TIME, "");
 
@@ -768,3 +763,37 @@ double speed_test(int converter, unsigned repeat)
 	t0 = t1 - t0;
 	return repeat / (t0.tv_sec + t0.tv_nsec/1e9);
 }
+
+void setup_signal_handlers(void)
+{
+	struct sigaction action;
+	memset(&action, 0, sizeof(struct sigaction));
+
+	action.sa_handler = SIG_DFL;
+	// no child stopped notifications, no zombies
+	action.sa_flags = SA_NOCLDSTOP | SA_NOCLDWAIT;
+	sigaction(SIGCHLD, &action, NULL);
+	action.sa_flags = 0;
+
+	// undo xmlrpc-c's signal handling
+#if USE_XMLRPC
+	sigaction(SIGTERM, &action, NULL);
+	sigaction(SIGINT, &action, NULL);
+	sigaction(SIGHUP, &action, NULL);
+	sigaction(SIGUSR1, &action, NULL);
+#endif
+
+	action.sa_handler = handle_signal;
+	sigaction(SIGSEGV, &action, NULL);
+	sigaction(SIGILL, &action, NULL);
+	sigaction(SIGABRT, &action, NULL);
+	sigaction(SIGUSR2, &action, NULL);
+
+	action.sa_handler = SIG_IGN;
+	sigaction(SIGPIPE, &action, NULL);
+
+	sigemptyset(&action.sa_mask);
+	sigaddset(&action.sa_mask, SIGUSR2);
+	pthread_sigmask((GET_THREAD_ID() == FLMAIN_TID ? SIG_BLOCK : SIG_UNBLOCK),
+			&action.sa_mask, NULL);
+}

src/misc/arq_io.cxx

@@ -37,6 +37,8 @@
 #  include <sys/msg.h>
 #endif
 
+#include <signal.h>
+
 #include "main.h"
 #include "configuration.h"
 #include "fl_digi.h"
@@ -291,11 +293,10 @@ ARQ_SOCKET_Server::ARQ_SOCKET_Server()
 ARQ_SOCKET_Server::~ARQ_SOCKET_Server()
 {
 	run = false;
-	if (arq_socket_thread) {
+	pthread_kill(*arq_socket_thread, SIGUSR2);
 	pthread_join(*arq_socket_thread, NULL);
 	delete arq_socket_thread;
 }
-}
 
 bool ARQ_SOCKET_Server::start(const char* node, const char* service)
 {
@@ -307,9 +308,6 @@ bool ARQ_SOCKET_Server::start(const char* node, const char* service)
 	try {
 		inst->server_socket->open(Address(node, service));
 		inst->server_socket->bind();
-		struct timeval t = { 0, 200000 };
-		inst->server_socket->set_timeout(t);
-		inst->server_socket->set_nonblocking();
 	}
 	catch (const SocketException& e) {
 		errstring = "Could not start ARQ server (";
@@ -342,18 +340,23 @@ void* ARQ_SOCKET_Server::thread_func(void*)
 {
 	SET_THREAD_ID(ARQSOCKET_TID);
 
+	setup_signal_handlers();
+
 	while (inst->run) {
 		try {
 			arq_run(inst->server_socket->accept());
 		}
 		catch (const SocketException& e) {
-			if (e.error() != ETIMEDOUT) {
+			if (e.error() != EINTR) {
 				errstring = e.what();
 				LOG_ERROR("%s", errstring.c_str());
 				Fl::add_timeout(0.0, popup_msg, (void*)errstring.c_str());
 				break;
 			}
 		}
+		catch (...) {
+			break;
+		}
 	}
 	arq_stop();
 	inst->server_socket->close();
@@ -362,10 +365,7 @@ void* ARQ_SOCKET_Server::thread_func(void*)
 
 void arq_run(Socket s)
 {
-	struct timeval t = { 0, 20000 }; // 0.02 second timeout
 	arqclient = s;
-	arqclient.set_timeout(t);
-	arqclient.set_nonblocking();
 	isSocketConnected = true;
 	arqmode = true;
 }

src/misc/stacktrace.cxx

@@ -80,6 +80,8 @@ void handle_unexpected(void)
 // this may not give us anything useful, but we can try...
 void handle_signal(int s)
 {
-        signum = s;
-        diediedie();
+	if (s != SIGUSR2) {
+		signum = s;
+		diediedie();
+	}
 }

src/misc/xmlrpc.cxx

@@ -33,6 +33,8 @@
 #include <exception>
 #include <cstdlib>
 
+#include <signal.h>
+
 #include <xmlrpc-c/base.hpp>
 #include <xmlrpc-c/registry.hpp>
 #include <xmlrpc-c/server_abyss.hpp>
@@ -86,6 +88,7 @@ XML_RPC_Server::XML_RPC_Server()
 XML_RPC_Server::~XML_RPC_Server()
 {
 	run = false;
+	pthread_kill(*server_thread, SIGUSR2);
 	pthread_join(*server_thread, NULL);
 	delete server_thread;
 	delete methods;
@@ -102,6 +105,7 @@ void XML_RPC_Server::start(const char* node, const char* service)
 
 	try {
 		inst->server_socket->open(Address(node, service));
+		inst->server_socket->bind();
 	}
 	catch (const SocketException& e) {
 		LOG_ERROR("Could not start XML-RPC server (%s)", e.what());
@@ -134,33 +138,23 @@ void* XML_RPC_Server::thread_func(void*)
 #endif
 	    		      );
 
-	try {
-		inst->server_socket->bind();
-		struct timeval t = { 0, 200000 };
-		inst->server_socket->set_timeout(t);
-		inst->server_socket->set_nonblocking();
-	}
-	catch (const SocketException& e) {
-		LOG_ERROR("Could not start XML-RPC server (%s)", e.what());
-		goto ret;
-	}
+	setup_signal_handlers();
 
 	while (inst->run) {
-		Socket client;
 		try {
 			server.runConn(inst->server_socket->accept().fd());
 		}
 		catch (const SocketException& e) {
-			if (e.error() != ETIMEDOUT) {
+			if (e.error() != EINTR)
 				LOG_ERROR("%s", e.what());
-				break;
-			}
+			break;
+		}
+		catch (...) {
+			break;
 		}
 	}
 
-ret:
 	inst->server_socket->close();
-
 	return NULL;
 }