dbus: rauc: add topic that enables/disables polling for updates

Polling for updates should only be done with user consent as it
creates a connection to our server, which has privacy implications.

Signed-off-by: Leonard Göhrs <[email protected]>

Author: hnez

demo_files/srv/tacd/state.json

@@ -2,6 +2,7 @@
   "format_version": 1,
   "persistent_topics": {
     "/v1/tac/display/show_help": false,
-    "/v1/tac/setup_mode": false
+    "/v1/tac/setup_mode": false,
+    "/v1/tac/update/enable_polling": true
   }
 }

openapi.yaml

@@ -743,6 +743,21 @@ paths:
               schema:
                 type: number
 
+  /v1/tac/update/enable_polling:
+    put:
+      summary: Enable periodic polling for operating system updates
+      tags: [Updating]
+      requestBody:
+        content:
+          application/json:
+            schema:
+              type: boolean
+      responses:
+        '204':
+          description: Polling for OS updates was enabled/disabled
+        '400':
+          description: The value could not be parsed as boolean
+
   /v1/tac/update/operation:
     get:
       summary: Get the currently running system update operation

src/broker/topic.rs

@@ -338,7 +338,6 @@ impl<E: Serialize + DeserializeOwned + Clone + PartialEq> Topic<E> {
     }
 
     /// Wait until the topic is set to the specified value
-    #[allow(dead_code)]
     pub async fn wait_for(self: &Arc<Self>, val: E) {
         let (mut stream, sub) = self.clone().subscribe_unbounded();
 

src/dbus/rauc.rs

@@ -104,6 +104,7 @@ pub struct Rauc {
     pub channels: Arc<Topic<Vec<Channel>>>,
     pub reload: Arc<Topic<bool>>,
     pub should_reboot: Arc<Topic<bool>>,
+    pub enable_polling: Arc<Topic<bool>>,
 }
 
 fn compare_versions(v1: &str, v2: &str) -> Option<Ordering> {
@@ -178,6 +179,7 @@ fn would_reboot_into_other_slot(slot_status: &SlotStatus, primary: Option<String
 
 async fn channel_polling_task(
     conn: Arc<Connection>,
+    enable_polling: Arc<Topic<bool>>,
     channels: Arc<Topic<Vec<Channel>>>,
     slot_status: Arc<Topic<Arc<SlotStatus>>>,
     name: String,
@@ -188,6 +190,10 @@ async fn channel_polling_task(
         .try_get()
         .and_then(|chs| chs.into_iter().find(|ch| ch.name == name))
     {
+        // Make sure update polling is enabled before doing anything,
+        // as contacting the update server requires user consent.
+        enable_polling.wait_for(true).await;
+
         let polling_interval = channel.polling_interval;
         let slot_status = slot_status.try_get();
 
@@ -224,6 +230,7 @@ async fn channel_polling_task(
 async fn channel_list_update_task(
     conn: Arc<Connection>,
     mut reload_stream: Receiver<bool>,
+    enable_polling: Arc<Topic<bool>>,
     channels: Arc<Topic<Vec<Channel>>>,
     slot_status: Arc<Topic<Arc<SlotStatus>>>,
 ) {
@@ -266,6 +273,7 @@ async fn channel_list_update_task(
         for name in names.into_iter() {
             let polling_task = spawn(channel_polling_task(
                 conn.clone(),
+                enable_polling.clone(),
                 channels.clone(),
                 slot_status.clone(),
                 name,
@@ -290,6 +298,14 @@ impl Rauc {
             channels: bb.topic_ro("/v1/tac/update/channels", None),
             reload: bb.topic_wo("/v1/tac/update/channels/reload", Some(true)),
             should_reboot: bb.topic_ro("/v1/tac/update/should_reboot", Some(false)),
+            enable_polling: bb.topic(
+                "/v1/tac/update/enable_polling",
+                true,
+                true,
+                true,
+                Some(false),
+                1,
+            ),
         }
     }
 
@@ -306,6 +322,7 @@ impl Rauc {
         spawn(channel_list_update_task(
             Arc::new(Connection),
             reload_stream,
+            inst.enable_polling.clone(),
             inst.channels.clone(),
             inst.slot_status.clone(),
         ));
@@ -488,6 +505,7 @@ impl Rauc {
         spawn(channel_list_update_task(
             conn.clone(),
             reload_stream,
+            inst.enable_polling.clone(),
             inst.channels.clone(),
             inst.slot_status.clone(),
         ));