[glib-networking/mcatanzaro/gnutls-pull-timeout-cancellation] gnutls: handle cancellation in pull timeout callback

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 2b2ecfe31ecd753c0661e69ab6046789a304e043
Author: Michael Catanzaro <mcatanzaro redhat com>
Date:   Wed Jun 2 13:58:47 2021 -0500

    gnutls: handle cancellation in pull timeout callback
    
    Ole André noticed that we should probably finish the timeout function
    immediately if the read is cancelled. The impact of this is probably not
    very great, since it only matters if the cancellable is cancelled from
    some other thread. It can't be cancelled on the thread that performed
    the read operation, because that thread is blocked in this pull timeout
    callback. :)

 tls/gnutls/gtlsconnection-gnutls.c | 48 +++++++++++++++++++++++++++-----------
 1 file changed, 34 insertions(+), 14 deletions(-)
---
diff --git a/tls/gnutls/gtlsconnection-gnutls.c b/tls/gnutls/gtlsconnection-gnutls.c
index 369a360..f99ba40 100644
--- a/tls/gnutls/gtlsconnection-gnutls.c
+++ b/tls/gnutls/gtlsconnection-gnutls.c
@@ -646,11 +646,11 @@ static gboolean
 read_pollable_cb (GPollableInputStream *istream,
                   gpointer              user_data)
 {
-  gboolean *read_done = user_data;
+  gboolean *done = user_data;
 
-  *read_done = TRUE;
+  *done = TRUE;
 
-  return G_SOURCE_CONTINUE;
+  return G_SOURCE_REMOVE;
 }
 
 static gboolean
@@ -658,19 +658,30 @@ read_datagram_based_cb (GDatagramBased *datagram_based,
                         GIOCondition    condition,
                         gpointer        user_data)
 {
-  gboolean *read_done = user_data;
+  gboolean *done = user_data;
 
-  *read_done = TRUE;
+  *done = TRUE;
 
-  return G_SOURCE_CONTINUE;
+  return G_SOURCE_REMOVE;
 }
 
 static gboolean
 read_timeout_cb (gpointer user_data)
 {
-  gboolean *timed_out = user_data;
+  gboolean *done = user_data;
+
+  *done = TRUE;
+
+  return G_SOURCE_REMOVE;
+}
+
+static gboolean
+read_cancelled_cb (GCancellable *cancellable,
+                   gpointer      user_data)
+{
+  gboolean *done = user_data;
 
-  *timed_out = TRUE;
+  *done = TRUE;
 
   return G_SOURCE_REMOVE;
 }
@@ -691,15 +702,17 @@ g_tls_connection_gnutls_pull_timeout_func (gnutls_transport_ptr_t transport_data
   if (ms > 0)
     {
       GMainContext *ctx = NULL;
-      GSource *read_source = NULL, *timeout_source = NULL;
-      gboolean read_done = FALSE, timed_out = FALSE;
+      GSource *read_source = NULL;
+      GSource *timeout_source = NULL;
+      GSource *cancellable_source = NULL;
+      gboolean done = FALSE;
 
       ctx = g_main_context_new ();
 
       /* Create a timeout source. */
       timeout_source = g_timeout_source_new (ms);
       g_source_set_callback (timeout_source, (GSourceFunc)read_timeout_cb,
-                             &timed_out, NULL);
+                             &done, NULL);
 
       /* Create a read source. We cannot use g_source_set_ready_time() on this
        * to combine it with the @timeout_source, as that could mess with the
@@ -709,28 +722,35 @@ g_tls_connection_gnutls_pull_timeout_func (gnutls_transport_ptr_t transport_data
           read_source = g_datagram_based_create_source (g_tls_connection_base_get_base_socket (tls),
                                                         G_IO_IN, NULL);
           g_source_set_callback (read_source, (GSourceFunc)read_datagram_based_cb,
-                                 &read_done, NULL);
+                                 &done, NULL);
         }
       else
         {
           read_source = g_pollable_input_stream_create_source (g_tls_connection_base_get_base_istream (tls),
                                                                NULL);
           g_source_set_callback (read_source, (GSourceFunc)read_pollable_cb,
-                                 &read_done, NULL);
+                                 &done, NULL);
         }
 
+      cancellable_source = g_cancellable_source_new (g_tls_connection_base_get_read_cancellable (tls));
+      g_source_set_callback (cancellable_source, (GSourceFunc)read_cancelled_cb,
+                             &done, NULL);
+
       g_source_attach (read_source, ctx);
       g_source_attach (timeout_source, ctx);
+      g_source_attach (cancellable_source, ctx);
 
-      while (!read_done && !timed_out)
+      while (!done)
         g_main_context_iteration (ctx, TRUE);
 
       g_source_destroy (read_source);
       g_source_destroy (timeout_source);
+      g_source_destroy (cancellable_source);
 
       g_main_context_unref (ctx);
       g_source_unref (read_source);
       g_source_unref (timeout_source);
+      g_source_unref (cancellable_source);
 
       /* If @read_source was dispatched due to cancellation, the resulting error
        * will be handled in g_tls_connection_gnutls_pull_func(). */