Change services identification mechanism

Let services identify themselves voiluntarily as the first operation
instead of polling from the monitor.
Also consolidate some common functions and make them available as monitor
helpers.

1 files changed, 154 insertions, 0 deletions

diff --git a/server/monitor/monitor_sbus.c b/server/monitor/monitor_sbus.c
index 817b42ae6..777a47fed 100644
--- a/server/monitor/monitor_sbus.c
+++ b/server/monitor/monitor_sbus.c
@@ -19,6 +19,11 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+/* Needed for res_init() */
+#include <netinet/in.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
+
 #include "util/util.h"
 #include "confdb/confdb.h"
 #include "sbus/sssd_dbus.h"
@@ -54,3 +59,152 @@ done:
     return ret;
 }
 
+static void id_callback(DBusPendingCall *pending, void *ptr)
+{
+    DBusMessage *reply;
+    DBusError dbus_error;
+    dbus_bool_t ret;
+    dbus_uint16_t mon_ver;
+    int type;
+
+    dbus_error_init(&dbus_error);
+
+    reply = dbus_pending_call_steal_reply(pending);
+    if (!reply) {
+        /* reply should never be null. This function shouldn't be called
+         * until reply is valid or timeout has occurred. If reply is NULL
+         * here, something is seriously wrong and we should bail out.
+         */
+        DEBUG(0, ("Severe error. A reply callback was called but no"
+                  " reply was received and no timeout occurred\n"));
+
+        /* FIXME: Destroy this connection ? */
+        goto done;
+    }
+
+    type = dbus_message_get_type(reply);
+    switch (type) {
+    case DBUS_MESSAGE_TYPE_METHOD_RETURN:
+        ret = dbus_message_get_args(reply, &dbus_error,
+                                    DBUS_TYPE_UINT16, &mon_ver,
+                                    DBUS_TYPE_INVALID);
+        if (!ret) {
+            DEBUG(1, ("Failed to parse message\n"));
+            if (dbus_error_is_set(&dbus_error)) dbus_error_free(&dbus_error);
+            /* FIXME: Destroy this connection ? */
+            goto done;
+        }
+
+        DEBUG(4, ("Got id ack and version (%d) from Monitor\n", mon_ver));
+
+        break;
+
+    case DBUS_MESSAGE_TYPE_ERROR:
+        DEBUG(0,("The Monitor returned an error [%s]\n",
+                 dbus_message_get_error_name(reply)));
+        /* Falling through to default intentionally*/
+    default:
+        /*
+         * Timeout or other error occurred or something
+         * unexpected happened.
+         * It doesn't matter which, because either way we
+         * know that this connection isn't trustworthy.
+         * We'll destroy it now.
+         */
+
+        /* FIXME: Destroy this connection ? */
+        break;
+    }
+
+done:
+    dbus_pending_call_unref(pending);
+    dbus_message_unref(reply);
+}
+
+int monitor_common_send_id(struct sbus_connection *conn,
+                           const char *name, uint16_t version)
+{
+    DBusPendingCall *pending_reply;
+    DBusConnection *dbus_conn;
+    DBusMessage *msg;
+    dbus_bool_t ret;
+
+    dbus_conn = sbus_get_connection(conn);
+
+    /* create the message */
+    msg = dbus_message_new_method_call(NULL,
+                                       MON_SRV_PATH,
+                                       MON_SRV_INTERFACE,
+                                       MON_SRV_METHOD_REGISTER);
+    if (msg == NULL) {
+        DEBUG(0, ("Out of memory?!\n"));
+        return ENOMEM;
+    }
+
+    DEBUG(4, ("Sending ID: (%s,%d)\n", name, version));
+
+    ret = dbus_message_append_args(msg,
+                                   DBUS_TYPE_STRING, &name,
+                                   DBUS_TYPE_UINT16, &version,
+                                   DBUS_TYPE_INVALID);
+    if (!ret) {
+        DEBUG(1, ("Failed to build message\n"));
+        return EIO;
+    }
+
+    ret = dbus_connection_send_with_reply(dbus_conn, msg, &pending_reply,
+                                          30000 /* TODO: set timeout */);
+    if (!ret || !pending_reply) {
+        /*
+         * Critical Failure
+         * We can't communicate on this connection
+         * We'll drop it using the default destructor.
+         */
+        DEBUG(0, ("D-BUS send failed.\n"));
+        dbus_message_unref(msg);
+        return EIO;
+    }
+
+    /* Set up the reply handler */
+    dbus_pending_call_set_notify(pending_reply, id_callback, NULL, NULL);
+    dbus_message_unref(msg);
+
+    return EOK;
+}
+
+int monitor_common_pong(DBusMessage *message,
+                        struct sbus_connection *conn)
+{
+    DBusMessage *reply;
+    dbus_bool_t ret;
+
+    reply = dbus_message_new_method_return(message);
+    if (!reply) return ENOMEM;
+
+    ret = dbus_message_append_args(reply, DBUS_TYPE_INVALID);
+    if (!ret) {
+        dbus_message_unref(reply);
+        return EIO;
+    }
+
+    /* send reply back */
+    sbus_conn_send_reply(conn, reply);
+    dbus_message_unref(reply);
+
+    return EOK;
+}
+
+int monitor_common_res_init(DBusMessage *message,
+                            struct sbus_connection *conn)
+{
+    int ret;
+
+    ret = res_init();
+    if(ret != 0) {
+        return EIO;
+    }
+
+    /* Send an empty reply to acknowledge receipt */
+    return monitor_common_pong(message, conn);
+}
+