Fix ^C ignored issue on CentOS 6.8.

lib/service/service.go

@@ -185,6 +185,9 @@ func (process *TeleportProcess) connectToAuthService(role teleport.Role) (*Conne
 // NewTeleport takes the daemon configuration, instantiates all required services
 // and starts them under a supervisor, returning the supervisor object
 func NewTeleport(cfg *Config) (*TeleportProcess, error) {
+	// before we do anything reset the SIGINT handler back to the default
+	utils.ResetInterruptSignalHandler()
+
 	if err := validateConfig(cfg); err != nil {
 		return nil, trace.Wrap(err, "Configuration error")
 	}

lib/utils/signal.go

@@ -0,0 +1,20 @@
+package utils
+
+/*
+#include <signal.h>
+void resetInterruptSignalHandler() {
+signal(SIGINT, SIG_DFL);
+}
+*/
+import "C"
+
+// ResetInterruptSignal will reset the handler for SIGINT back to the default
+// handler. We need to do this because when sysvinit launches Teleport on some
+// operating systems (like CentOS 6.8) it configures Teleport to ignore SIGINT
+// signals. See the following for more details:
+//
+// http://garethrees.org/2015/08/07/ping/
+// https://github.com/openssh/openssh-portable/commit/4e0f5e1ec9b6318ef251180dbca50eaa01f74536
+func ResetInterruptSignalHandler() {
+	C.resetInterruptSignalHandler()
+}