libctrl: Add support for 'deferred control commands'
Sometimes a control interface command cannot be processed
and responded immediately, but we need to process it asynchronously.
In order to support this, we introduce the 'ctrl_cmd_def', which
represents such a deferred command. It is created by the service
implementing the command using ctrl_cmd_def_make(), and a response is
later sent using ctrl_cmd_def_send().
ctrl_cmd_def_is_zombie() must be called to handle the case where
the control connection has disconnected/died between receiving the
command and sending the response.
diff --git a/src/ctrl/control_cmd.c b/src/ctrl/control_cmd.c
index 88a30a2..4e156b8 100644
--- a/src/ctrl/control_cmd.c
+++ b/src/ctrl/control_cmd.c
@@ -487,3 +487,63 @@
msgb_free(msg);
return NULL;
}
+
+struct ctrl_cmd_def *
+ctrl_cmd_def_make(const void *ctx, struct ctrl_cmd *cmd, void *data, unsigned int secs)
+{
+ struct ctrl_cmd_def *cd;
+
+ if (!cmd->ccon)
+ return NULL;
+
+ cd = talloc_zero(ctx, struct ctrl_cmd_def);
+
+ cd->cmd = cmd;
+ cd->data = data;
+
+ /* add to per-connection list of deferred commands */
+ llist_add(&cd->list, &cmd->ccon->def_cmds);
+
+ return cd;
+}
+
+int ctrl_cmd_def_is_zombie(struct ctrl_cmd_def *cd)
+{
+ /* luckily we're still alive */
+ if (cd->cmd)
+ return 0;
+
+ /* if we are a zombie, make sure we really die */
+ llist_del(&cd->list);
+ talloc_free(cd);
+
+ return 1;
+}
+
+int ctrl_cmd_def_send(struct ctrl_cmd_def *cd)
+{
+ struct ctrl_cmd *cmd = cd->cmd;
+
+ int rc;
+
+ /* Deferred commands can only be responses to GET/SET or ERROR, but
+ * never TRAP or anything else */
+ switch (cmd->type) {
+ case CTRL_TYPE_GET:
+ cmd->type = CTRL_TYPE_GET_REPLY;
+ break;
+ case CTRL_TYPE_SET:
+ cmd->type = CTRL_TYPE_SET_REPLY;
+ break;
+ default:
+ cmd->type = CTRL_TYPE_ERROR;
+ }
+
+ rc = ctrl_cmd_send(&cmd->ccon->write_queue, cmd);
+
+ talloc_free(cmd);
+ llist_del(&cd->list);
+ talloc_free(cd);
+
+ return rc;
+}
diff --git a/src/ctrl/control_if.c b/src/ctrl/control_if.c
index 59cf255..c20c1e0 100644
--- a/src/ctrl/control_if.c
+++ b/src/ctrl/control_if.c
@@ -128,6 +128,8 @@
static void control_close_conn(struct ctrl_connection *ccon)
{
+ struct ctrl_cmd_def *cd, *cd2;
+
osmo_wqueue_clear(&ccon->write_queue);
close(ccon->write_queue.bfd.fd);
osmo_fd_unregister(&ccon->write_queue.bfd);
@@ -135,6 +137,19 @@
if (ccon->closed_cb)
ccon->closed_cb(ccon);
msgb_free(ccon->pending_msg);
+
+ /* clean up deferred commands */
+ llist_for_each_entry_safe(cd, cd2, &ccon->def_cmds, list) {
+ /* delete from list of def_cmds for this ccon */
+ llist_del(&cd->list);
+ /* not strictly needed as this is a slave to the ccon which we
+ * are about to free anyway */
+ talloc_free(cd->cmd);
+ /* set the CMD to null, this is the indication to the user that
+ * the connection for this command has gone */
+ cd->cmd = NULL;
+ }
+
talloc_free(ccon);
}
@@ -338,6 +353,8 @@
/* Error handling here? */
INIT_LLIST_HEAD(&ccon->cmds);
+ INIT_LLIST_HEAD(&ccon->def_cmds);
+
return ccon;
}