watcher: sdbus module to control processes

diff --git a/utils/watcher/dbus_control.c b/utils/watcher/dbus_control.c
new file mode 100644 (file)
index 0000000..ccba907
--- /dev/null
+++ b/utils/watcher/dbus_control.c
@@ -0,0 +1,166 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <systemd/sd-bus.h>
+
+#include "contrib/ccan/asprintf/asprintf.h"
+#include "dbus_control.h"
+
+#define DBUS_NAME_SYSTEMD   "org.freedesktop.systemd1"
+/* DBus services paths. */
+#define DBUS_PATH_SYSTEMD   "/org/freedesktop/systemd1"
+#define DBUS_PATH_KRESD     DBUS_PATH_SYSTEMD"/unit/kresd_40%s_2eservice"
+#define DBUS_PATH_GC        DBUS_PATH_SYSTEMD"/unit/kres_2dcache_2dgc_2eservice"
+/* DBus interfaces. */
+#define DBUS_INTF_BASE      "org.freedesktop"
+#define DBUS_INTR_MAN       DBUS_INTF_BASE".systemd1.Manager"
+#define DBUS_INTR_PROP      DBUS_INTF_BASE".DBus.Properties"
+#define DBUS_INTR_UNIT      DBUS_INTF_BASE".systemd1.Unit"
+/* Services names. */
+#define SERVICE_KRESD       "kresd@%s.service"
+#define SERVICE_CACHE_GC    "kres-cache-gc.service"
+
+
+/* Convert method_t(enum) to string. */
+static const char *strmethod(method_t method)
+{
+       static const char *method_string[] = {
+               "StartUnit",
+               "StopUnit",
+               "RestartUnit",
+               "ReloadUnit"
+       };
+       return method_string[method];
+}
+
+void dbus_clean(void)
+{
+       sd_bus* bus = NULL;
+       sd_bus_default_system(&bus);
+       sd_bus_flush(bus);
+       sd_bus_close(bus);
+}
+
+int kresd_status(const char *instance, char **status)
+{
+       sd_bus* bus = NULL;
+       void* userdata = NULL;
+       char *instance_service;
+       sd_bus_error err = SD_BUS_ERROR_NULL;
+
+       int ret = sd_bus_default_system(&bus);
+
+       asprintf(&instance_service, DBUS_PATH_KRESD, instance);
+
+       ret = sd_bus_get_property_string(
+               bus,
+               DBUS_NAME_SYSTEMD,
+               instance_service,
+               DBUS_INTR_UNIT,
+               "ActiveState",
+               &err,
+               status
+       );
+       free(instance_service);
+
+       return ret;
+}
+
+int cache_gc_status(char **status)
+{
+       sd_bus* bus = NULL;
+       void* userdata = NULL;
+       sd_bus_error err = SD_BUS_ERROR_NULL;
+
+       int ret = sd_bus_default_system(&bus);
+
+       ret = sd_bus_get_property_string(
+               bus,
+               DBUS_NAME_SYSTEMD,
+               DBUS_PATH_GC,
+               DBUS_INTR_UNIT,
+               "ActiveState",
+               &err,
+               status
+       );
+       return ret;
+}
+
+int kresd_control(method_t method, const char *instance)
+{
+       sd_bus* bus = NULL;
+       sd_bus_message *reply = NULL;
+       sd_bus_error error = SD_BUS_ERROR_NULL;
+
+       char *instance_service;
+       const char *unit_method = strmethod(method);
+       asprintf(&instance_service, SERVICE_KRESD, instance);
+
+       int ret = sd_bus_default_system(&bus);
+
+       ret = sd_bus_call_method(
+               bus,
+               DBUS_NAME_SYSTEMD,
+               DBUS_PATH_SYSTEMD,
+               DBUS_INTR_MAN,
+               unit_method,
+               &error, &reply,
+               "ss",
+               instance_service,
+               "replace"
+       );
+
+       if (ret < 0) {
+               printf(
+                       "[sdbus] failed to issue method call '%s' %s: %s\n",
+                       strmethod(method), instance_service, error.message);
+               goto cleanup;
+       }
+
+       printf("[sdbus] %s %s\n", strmethod(method), instance_service);
+
+       cleanup:
+       free(instance_service);
+       sd_bus_error_free(&error);
+       sd_bus_message_unref(reply);
+
+       return ret;
+}
+
+int cache_gc_control(method_t method)
+{
+       sd_bus* bus = NULL;
+       sd_bus_message *reply = NULL;
+       sd_bus_error error = SD_BUS_ERROR_NULL;
+
+       const char *unit_method = strmethod(method);
+
+       int ret = sd_bus_default_system(&bus);
+
+       ret = sd_bus_call_method(
+               bus,
+               DBUS_NAME_SYSTEMD,
+               DBUS_PATH_SYSTEMD,
+               DBUS_INTR_MAN,
+               unit_method,
+               &error,
+               &reply,
+               "ss",
+               SERVICE_CACHE_GC,
+               "replace"
+       );
+
+       if (ret < 0) {
+               printf(
+                       "[sdbus] failed to issue method call '%s' %s: %s\n",
+                       unit_method, SERVICE_CACHE_GC, error.message);
+               goto cleanup;
+       }
+
+       printf("[sdbus] %s %s\n", unit_method, SERVICE_CACHE_GC);
+
+       cleanup:
+       sd_bus_error_free(&error);
+       sd_bus_message_unref(reply);
+
+       return ret;
+}
\ No newline at end of file

diff --git a/utils/watcher/dbus_control.h b/utils/watcher/dbus_control.h
new file mode 100644 (file)
index 0000000..e3b1136
--- /dev/null
+++ b/utils/watcher/dbus_control.h
@@ -0,0 +1,27 @@
+#pragma once
+
+#include <systemd/sd-bus.h>
+
+
+/** Enumeration of operations, that can be used to control units(services). */
+typedef enum method_e {
+       UNIT_START,     /** Start unit(service). */
+       UNIT_STOP,      /** Stop unit(service). */
+       UNIT_RESTART,   /** Restart unit(service). */
+       UNIT_RELOAD     /** Reload unit(service). */
+} method_t;
+
+/** Cleans all unclosed DBus connections. */
+void dbus_clean(void);
+
+/** Get status of specific kresd instance. */
+int kresd_status(const char *instance, char **status);
+
+/** Get status of cache garbage collector. */
+int cache_gc_status(char **status);
+
+/** Control specific kresd instance. */
+int kresd_control(method_t method, const char *instance);
+
+/** Control cache garbage collector. */
+int cache_gc_control(method_t method);