vm: disable SIGINT handler while in factorbug

Fixes #410

vm/debug.cpp

@@ -476,6 +476,7 @@ void factor_vm::factorbug_usage(bool advanced_p)
 static void exit_fep(factor_vm *vm)
 {
 	vm->unlock_console();
+	vm->handle_ctrl_c();
 	vm->fep_p = false;
 }
 
@@ -498,6 +499,7 @@ void factor_vm::factorbug()
 	// that pumps the console is still running concurrently. We lock a mutex so
 	// the thread will take a break and give us exclusive access to stdin.
 	lock_console();
+	ignore_ctrl_c();
 
 	if (!fep_help_was_shown) {
 		factorbug_usage(false);

vm/os-unix.cpp

@@ -318,7 +318,6 @@ void factor_vm::unix_init_signals()
 	struct sigaction memory_sigaction;
 	struct sigaction synchronous_sigaction;
 	struct sigaction enqueue_sigaction;
-	struct sigaction fep_sigaction;
 	struct sigaction sample_sigaction;
 	struct sigaction fpe_sigaction;
 	struct sigaction ignore_sigaction;
@@ -347,8 +346,7 @@ void factor_vm::unix_init_signals()
 	sigaction_safe(SIGINFO,&enqueue_sigaction,NULL);
 #endif
 
-	init_sigaction_with_handler(&fep_sigaction, fep_signal_handler);
+	handle_ctrl_c();
-	sigaction_safe(SIGINT,&fep_sigaction,NULL);
 
 	init_sigaction_with_handler(&sample_sigaction, sample_signal_handler);
 	sigaction_safe(SIGALRM,&sample_sigaction,NULL);
@@ -528,6 +526,23 @@ void factor_vm::unlock_console()
 	pthread_mutex_unlock(&stdin_mutex);
 }
 
+void factor_vm::ignore_ctrl_c()
+{
+	sig_t ret;
+	do
+	{
+		ret = signal(SIGINT, SIG_DFL);
+	}
+	while(ret == SIG_ERR && errno == EINTR);
+}
+
+void factor_vm::handle_ctrl_c()
+{
+	struct sigaction fep_sigaction;
+	init_sigaction_with_handler(&fep_sigaction, fep_signal_handler);
+	sigaction_safe(SIGINT,&fep_sigaction,NULL);
+}
+
 void factor_vm::abort()
 {
 	sig_t ret;

vm/os-windows.cpp

@@ -305,6 +305,16 @@ static BOOL WINAPI ctrl_handler(DWORD dwCtrlType)
 }
 
 void factor_vm::open_console()
+{
+	handle_ctrl_c();
+}
+
+void factor_vm::ignore_ctrl_c()
+{
+	SetConsoleCtrlHandler(factor::ctrl_handler, FALSE);
+}
+
+void factor_vm::handle_ctrl_c()
 {
 	SetConsoleCtrlHandler(factor::ctrl_handler, TRUE);
 }

vm/vm.hpp

@@ -736,6 +736,8 @@ struct factor_vm
 	static void close_console();
 	static void lock_console();
 	static void unlock_console();
+	static void ignore_ctrl_c();
+	static void handle_ctrl_c();
 	static void abort();
 	static void exit();