Add initial systemd integration

1 files changed, 321 insertions, 0 deletions

diff --git a/systemd.c b/systemd.c
new file mode 100644
index 0000000..f556a55
--- /dev/null
+++ b/systemd.c
@@ -0,0 +1,321 @@
+#include <string.h>
+#include <stdlib.h>
+#include <systemd/sd-bus.h>
+
+#include "main.h"
+#include "server.h"
+#include "systemd.h"
+
+#define SYSTEMD_DBUS_SERVICE		"org.freedesktop.systemd1"
+#define SYSTEMD_DBUS_INTERFACE		"org.freedesktop.systemd1.Unit"
+#define SYSTEMD_DBUS_PATH_PREFIX	"/org/freedesktop/systemd1/unit/"
+
+static inline char
+tohex(uint8_t val)
+{
+	static const char hex[] = "0123456789abcdef";
+
+	return hex[val & 0x0f];
+}
+
+/*
+ * Creates an escaped D-Bus object path for a given systemd service
+ *
+ * Escaping rules are documented here:
+ * https://dbus.freedesktop.org/doc/dbus-specification.html
+ *
+ * Essentially, everyting but a-z, A-Z, 0-9 is replaced by _xx where xx is
+ * the hexadecimal value of the character.
+ *
+ * Example: minecraft@world1.service -> minecraft_40world1_2eservice
+ */
+char *
+systemd_service_object_path(struct cfg *cfg, const char *service)
+{
+	char *r;
+	char *d;
+	const char *s;
+
+	if (empty_str(service)) {
+		fprintf(stderr, "%s: called with NULL arg\n", __func__);
+		return NULL;
+	}
+
+	r = malloc(strlen(SYSTEMD_DBUS_PATH_PREFIX) + strlen(service) * 3 + 1);
+	if (!r)
+		return NULL;
+
+	memcpy(r, SYSTEMD_DBUS_PATH_PREFIX, strlen(SYSTEMD_DBUS_PATH_PREFIX));
+	d = r + strlen(SYSTEMD_DBUS_PATH_PREFIX);
+
+	for (s = service; *s; s++) {
+		if ((*s >= 'a' && *s <= 'z') ||
+		    (*s >= 'A' && *s <= 'Z') ||
+		    (*s >= '0' && *s <= '9')) {
+			*(d++) = *s;
+			continue;
+		}
+
+		*(d++) = '_';
+		*(d++) = tohex(*s >> 4);
+		*(d++) = tohex(*s);
+	}
+
+	*d = '\0';
+	return r;
+}
+
+void
+systemd_delete(struct cfg *cfg)
+{
+	if (!cfg->sd_bus)
+		return;
+
+        sd_bus_unref(cfg->sd_bus);
+	cfg->sd_bus = NULL;
+}
+
+static sd_bus *
+get_bus(struct cfg *cfg)
+{
+	int r;
+
+	if (cfg->sd_bus_failed)
+		return NULL;
+
+	if (!cfg->sd_bus) {
+		r = sd_bus_open_user(&cfg->sd_bus);
+		if (r < 0) {
+			fprintf(stderr, "Failed to connect to user system bus: %s\n", strerror(-r));
+			cfg->sd_bus_failed = true;
+			return NULL;
+		}
+	}
+
+	return cfg->sd_bus;
+}
+
+/*
+ * Check if a systemd service is running.
+ *
+ * This is equivalent to (assuming service minecraft@world1):
+ *   gdbus call --session 
+ *	--dest org.freedesktop.systemd1 
+ *	--object-path /org/freedesktop/systemd1/unit/minecraft_40world1_2eservice
+ *	--method org.freedesktop.DBus.Properties.Get
+ *		"org.freedesktop.systemd1.Unit" 
+ *		"ActiveState"
+ */
+bool
+systemd_service_running(struct cfg *cfg, struct server *server)
+{
+	sd_bus *bus = get_bus(cfg);
+        sd_bus_error error = SD_BUS_ERROR_NULL;
+	char *status = NULL;
+	int r;
+	bool running = false;
+
+	if (!bus || !server->systemd_service || !server->systemd_obj)
+		return false;
+
+	r = sd_bus_get_property_string(bus,
+				       SYSTEMD_DBUS_SERVICE,
+				       server->systemd_obj,
+				       SYSTEMD_DBUS_INTERFACE,
+				       "ActiveState",
+				       &error,
+				       &status);
+        if (r < 0) {
+                fprintf(stderr, "%s: failed to get status for service %s (%s): %s\n",
+			__func__, server->systemd_service, server->systemd_obj, error.message);
+		goto out;
+        }
+
+	if (!strcmp(status, "active")) {
+		running = true;
+		fprintf(stderr, "Systemd service %s (%s) is active\n",
+			server->systemd_service, server->systemd_obj);
+	} else
+		fprintf(stderr, "Systemd service %s (%s) is not active\n",
+			server->systemd_service, server->systemd_obj);
+
+out:
+	free(status);
+        sd_bus_error_free(&error);
+	return running;
+}
+
+static bool
+systemd_service_action(struct cfg *cfg, struct server *server, const char *action)
+{
+        sd_bus_error error = SD_BUS_ERROR_NULL;
+        sd_bus_message *m = NULL;
+	sd_bus *bus = get_bus(cfg);
+	const char *path;
+	bool performed = false;
+	int r;
+
+	if (!bus || !server->systemd_service || !server->systemd_obj || !action)
+		return false;
+
+        r = sd_bus_call_method(bus,
+			       SYSTEMD_DBUS_SERVICE,
+			       server->systemd_obj,
+			       SYSTEMD_DBUS_INTERFACE,
+			       action,
+			       &error,
+			       &m,
+			       "s",
+			       "fail");
+        if (r < 0) {
+                fprintf(stderr, "Failed to perform action %s on systemd service %s: %s\n",
+			action, server->systemd_service, error.message);
+		goto out;
+        }
+
+        r = sd_bus_message_read(m, "o", &path);
+        if (r < 0) {
+                fprintf(stderr, "Failed to parse response message: %s\n", strerror(-r));
+		goto out;
+        }
+
+        fprintf(stderr, "Queued %s on service %s as %s\n",
+		action, server->systemd_service, path);
+	performed = true;
+
+out:
+        sd_bus_error_free(&error);
+        sd_bus_message_unref(m);
+	return performed;
+}
+
+/*
+ * Stop systemd service.
+ *
+ * This is equivalent to (assuming service minecraft@world1):
+ *   gdbus call --session 
+ *	--dest org.freedesktop.systemd1 
+ *	--object-path /org/freedesktop/systemd1/unit/minecraft_40world1_2eservice
+ *	--method org.freedesktop.systemd1.Unit.Stop "fail"
+ */
+bool
+systemd_service_stop(struct cfg *cfg, struct server *server)
+{
+	return systemd_service_action(cfg, server, "Stop");
+}
+
+/*
+ * Start systemd service.
+ *
+ * This is equivalent to (assuming service minecraft@world1):
+ *   gdbus call --session 
+ *	--dest org.freedesktop.systemd1 
+ *	--object-path /org/freedesktop/systemd1/unit/minecraft_40world1_2eservice
+ *	--method org.freedesktop.systemd1.Unit.Start "fail"
+ */
+bool
+systemd_service_start(struct cfg *cfg, struct server *server)
+{
+	return systemd_service_action(cfg, server, "Start");
+}
+
+
+#if 0
+
+
+
+
+int main(int argc, char *argv[]) {
+        sd_bus_error error = SD_BUS_ERROR_NULL;
+        sd_bus_message *m = NULL;
+        sd_bus *bus = NULL;
+        const char *path;
+        int r;
+
+        /* Connect to the system bus */
+        r = sd_bus_open_user(&bus);
+        if (r < 0) {
+                fprintf(stderr, "Failed to connect to system bus: %s\n", strerror(-r));
+                goto finish;
+        }
+
+        /* Issue the method call and store the respons message in m */
+        r = sd_bus_call_method(bus,
+                               "org.freedesktop.systemd1",           /* service to contact */
+                               "/org/freedesktop/systemd1",          /* object path */
+                               "org.freedesktop.systemd1.Manager",   /* interface name */
+                               "StartUnit",                          /* method name */
+                               &error,                               /* object to return error in */
+                               &m,                                   /* return message on success */
+                               "ss",                                 /* input signature */
+                               "apa.service",                       /* first argument */
+                               "fail");                           /* second argument */
+        if (r < 0) {
+                fprintf(stderr, "Failed to issue method call: %s\n", error.message);
+                goto finish;
+        }
+
+        /* Parse the response message */
+        r = sd_bus_message_read(m, "o", &path);
+        if (r < 0) {
+                fprintf(stderr, "Failed to parse response message: %s\n", strerror(-r));
+		goto finish;
+        }
+        printf("Queued service job as %s.\n", path);
+
+        sd_bus_error_free(&error);
+        sd_bus_message_unref(m);
+        error = SD_BUS_ERROR_NULL;
+        m = NULL;
+
+	/*
+	   gdbus call --session
+	   --dest org.freedesktop.systemd1 
+	   --object-path /org/freedesktop/systemd1/unit/myapa_40local2_2eservice 
+	   --method org.freedesktop.systemd1.Unit.Start "fail"
+
+	   gdbus introspect --session
+	   --dest org.freedesktop.systemd1
+	   --object-path /org/freedesktop/systemd1/unit/myapa_40local_2eservice
+
+	   gdbus call --session 
+	   --dest org.freedesktop.systemd1 
+	   --object-path /org/freedesktop/systemd1/unit/myapa_40basker_2eservice
+	   --method org.freedesktop.DBus.Properties.Get
+	   "org.freedesktop.systemd1.Unit" 
+	   "ActiveState"
+	   */
+	char *res;
+	r = sd_bus_get_property_string(bus,
+				       "org.freedesktop.systemd1",
+				       "/org/freedesktop/systemd1/unit/apa_2eservice",
+				       "org.freedesktop.systemd1.Unit",
+				       "ActiveState",
+				       &error,
+				       &res);
+        if (r < 0) {
+                fprintf(stderr, "Failed to issue prop call: %s\n", error.message);
+                goto finish;
+        }
+
+	fprintf(stderr, "RESULT: %s\n", res);
+/*
+	int sd_bus_get_property_string(sd_bus *bus,
+				       const char *destination,
+				       const char *path,
+				       const char *interface,
+				       const char *member,
+				       sd_bus_error *ret_error,
+				       char **ret);
+				       */
+/*
+finish:
+        sd_bus_error_free(&error);
+        sd_bus_message_unref(m);
+        sd_bus_unref(bus);
+	*/
+
+finish:
+        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+}
+#endif