osctld: make Container::Stop wait for console being closed

Author: aither64

osctld/lib/osctld/commands/container/stop.rb

@@ -51,6 +51,9 @@ def execute(ct)
         # in low memory situations.
         ct.cgparams.temporarily_expand_memory if ct.running?
 
+        run_conf = ct.get_run_conf
+        promise = run_conf.get_exit_promise if run_conf.init_pid
+
         begin
           DistConfig.run(
             ct.get_run_conf,
@@ -71,6 +74,10 @@ def execute(ct)
           error!(e.message)
         end
 
+        if promise && promise.wait.nil?
+          log(:warn, "Timeout while waiting for exit promise of #{ct.ident}")
+        end
+
         remove_accounting_cgroups(ct)
 
         if ct.ephemeral? && !indirect?

osctld/lib/osctld/console/console.rb

@@ -75,15 +75,10 @@ def on_ct_stop
         )
       end
 
-      if ctrc.aborted? \
-         || ctrc.reboot? \
-         || (ct.ephemeral? && !ct.is_being_manipulated?) \
-         || ctrc.destroy_dataset_on_stop?
-        # The current thread is used to handle the console and has to exit.
-        # Manipulation must happen from another thread.
-        t = Thread.new { handle_ct_stop(ctrc) }
-        ThreadReaper.add(t, nil)
-      end
+      # The current thread is used to handle the console and has to exit.
+      # Manipulation must happen from another thread.
+      t = Thread.new { handle_ct_stop(ctrc) }
+      ThreadReaper.add(t, nil)
 
       ct.forget_past_run_conf
     end
@@ -105,6 +100,8 @@ def handle_ct_stop(ctrc)
         GarbageCollector.free_container_run_dataset(ctrc, ctrc.dataset)
       end
 
+      ctrc.fulfil_exit
+
       if ctrc.reboot?
         sleep(1)
         reboot_ct

osctld/lib/osctld/container/run_configuration.rb

@@ -35,6 +35,7 @@ def initialize(ct, load_conf: true)
       @init_pid = nil
       @aborted = false
       @do_reboot = false
+      @exit_promise = Promise.new
       @dist_network_configured = false
       self.load_conf(from_file: load_conf)
     end
@@ -149,6 +150,14 @@ def reboot?
       @do_reboot
     end
 
+    def get_exit_promise
+      @exit_promise.add
+    end
+
+    def fulfil_exit
+      @exit_promise.fulfil
+    end
+
     def dist_configure_network?
       inclusively do
         !dist_network_configured && can_dist_configure_network?

osctld/lib/osctld/promise.rb

@@ -0,0 +1,40 @@
+require 'libosctl'
+
+module OsCtld
+  class Promise
+    class Token
+      def initialize
+        @queue = OsCtl::Lib::Queue.new
+      end
+
+      # Wait until the promise is fulfilled
+      # @param timeout [Integer]
+      # @return [true, nil]
+      def wait(timeout: 60)
+        @queue.pop(timeout:)
+      end
+
+      # Fulfil the promise
+      def fulfil
+        @queue << true
+      end
+    end
+
+    def initialize
+      @mutex = Mutex.new
+      @tokens = []
+    end
+
+    # @return [Token]
+    def add
+      t = Token.new
+      @tokens << t
+      t
+    end
+
+    def fulfil
+      @tokens.each(&:fulfil)
+      nil
+    end
+  end
+end