api: implement restart action

lib/api/actions/reload.c

@@ -1,4 +1,4 @@
-/** The "restart" API ressource.
+/** The "restart" API action.
  *
  * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
  * @copyright 2017, Institute for Automation of Complex Power Systems, EONERC
@@ -22,11 +22,64 @@
 
 #include "plugin.h"
 #include "api.h"
+#include "super_node.h"
+
+#include "log.h"
+
+static char *config;
+
+void api_restart_handler()
+{
+	int ret;
+	
+	char *argv[] = { "villas-node", config, NULL };
+
+	ret = execvpe("/proc/self/exe", argv, environ);
+	if (ret)
+		serror("Failed to restart");
+}
 
-/** @todo not implemented yet */
 static int api_restart(struct api_action *h, json_t *args, json_t **resp, struct api_session *s)
 {
-	return -1;
+	int ret;
+	json_error_t err;
+	
+	/* If no config is provided via request, we will use the previous one */
+	config = strdup(s->api->super_node->uri);
+	
+	if (args) {
+		ret = json_unpack_ex(args, &err, 0, "{ s?: s }", "config", &config);
+		if (ret < 0) {
+			*resp = json_string("failed to parse request");
+			return -1;
+		}
+	}
+
+	/* Increment API restart counter */
+	char *scnt = getenv("VILLAS_API_RESTART_COUNT");
+	int cnt = scnt ? atoi(scnt) : 0;
+	char buf[32];
+	snprintf(buf, sizeof(buf), "%d", cnt + 1);
+
+	/* We pass some env variables to the new process */
+	setenv("VILLAS_API_RESTART_COUNT", buf, 1);
+	setenv("VILLAS_API_RESTART_REMOTE", s->peer.ip, 1);
+	
+	*resp = json_pack("{ s: i, s: s, s: s }",
+		"restarts", cnt,
+		"config", config,
+		"remote", s->peer.ip
+	);
+
+	/* Register exit handler */
+	ret = atexit(api_restart_handler);
+	if (ret)
+		return 0;
+	
+	/* Properly terminate current instance */
+	killme(SIGTERM);
+
+	return 0;
 }
 
 static struct plugin p = {

lib/utils.c

@@ -302,7 +302,7 @@ int signals_init(void (*cb)(int signal, siginfo_t *sinfo, void *ctx))
 	info("Initialize signals");
 
 	struct sigaction sa_quit = {
-		.sa_flags = SA_SIGINFO,
+		.sa_flags = SA_SIGINFO | SA_NODEFER,
 		.sa_sigaction = cb
 	};