File PackageKit-cancel-transaction-if-daemon-disappears.patch of Package PackageKit.20954
From b2452c2d0023aad6be0751f9785e20f34bed6887 Mon Sep 17 00:00:00 2001
From: Philip Withnall <pwithnall@endlessos.org>
Date: Fri, 19 Mar 2021 22:43:16 +0000
Subject: [PATCH 1/2] packagekit-glib2: Cancel a transaction if the daemon
disappears
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Most of the time, when using a `GDBusProxy`, and the service you’re
talking to disappears, you’ll get notified — the async D-Bus call you’re
making will return an error. However, due to PackageKit’s design for
handling long-running operations, there are long periods between a
transaction being created, and emitting its `Finished` signal, when no
D-Bus calls are pending.
If the daemon crashes during one of these periods, there is currently no
way for the packagekit-glib2 client code to notice until it tries to
make another D-Bus call on the same `GDBusProxy` instance, and that
might never happen — it might wait for the `Finished` signal forever.
Avoid that by connecting to `notify::g-name-owner`, which is emitted on
`GDBusProxy` if the daemon crashes. It changes value from the unique
name of the service, to `NULL`. When that happens, abort the transaction
state in the client with an error.
This should stop gnome-software hanging indefinitely if PackageKit
crashes during a transaction. In particular, if this happens a few times
during consecutive refresh operations, gnome-software can eventually run
out of worker threads, and become unresponsive entirely. (See
https://gitlab.gnome.org/GNOME/gnome-software/-/issues/1118.) The same
will likely be true of other clients which use packagekit-glib2.
Equivalent changes don’t seem to be needed in `pk-control.c` (which also
uses `GDBusProxy`), because all of its D-Bus operations appear to
maintain no state outside of individual method calls.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
---
lib/packagekit-glib2/pk-client.c | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)
diff --git a/lib/packagekit-glib2/pk-client.c b/lib/packagekit-glib2/pk-client.c
index 3f7d5230d..67df1c5ea 100644
--- a/lib/packagekit-glib2/pk-client.c
+++ b/lib/packagekit-glib2/pk-client.c
@@ -122,6 +122,9 @@ typedef struct {
PkClientHelper *client_helper;
} PkClientState;
+static void
+pk_client_state_finish (PkClientState *state,
+ const GError *error);
static void
pk_client_properties_changed_cb (GDBusProxy *proxy,
GVariant *changed_properties,
@@ -133,6 +136,10 @@ pk_client_signal_cb (GDBusProxy *proxy,
const gchar *signal_name,
GVariant *parameters,
gpointer user_data);
+static void
+pk_client_notify_name_owner_cb (GObject *obj,
+ GParamSpec *pspec,
+ gpointer user_data);
/**
* pk_client_error_quark:
@@ -662,6 +669,9 @@ pk_client_state_finish (PkClientState *state, const GError *error)
g_signal_handlers_disconnect_by_func (state->proxy,
G_CALLBACK (pk_client_signal_cb),
state);
+ g_signal_handlers_disconnect_by_func (state->proxy,
+ G_CALLBACK (pk_client_notify_name_owner_cb),
+ state);
g_object_unref (G_OBJECT (state->proxy));
}
@@ -1389,6 +1399,19 @@ pk_client_signal_cb (GDBusProxy *proxy,
return;
}
+static void
+pk_client_notify_name_owner_cb (GObject *obj,
+ GParamSpec *pspec,
+ gpointer user_data)
+{
+ PkClientState *state = (PkClientState *) user_data;
+ g_autoptr(GError) local_error = NULL;
+
+ local_error = g_error_new_literal (PK_CLIENT_ERROR, PK_CLIENT_ERROR_FAILED,
+ "PackageKit daemon disappeared");
+ pk_client_state_finish (state, local_error);
+}
+
/*
* pk_client_proxy_connect:
**/
@@ -1416,6 +1439,9 @@ pk_client_proxy_connect (PkClientState *state)
g_signal_connect (state->proxy, "g-signal",
G_CALLBACK (pk_client_signal_cb),
state);
+ g_signal_connect (state->proxy, "notify::g-name-owner",
+ G_CALLBACK (pk_client_notify_name_owner_cb),
+ state);
}
/*
@@ -1440,7 +1466,7 @@ pk_client_method_cb (GObject *source_object,
return;
}
- /* wait for ::Finished() */
+ /* wait for ::Finished() or notify::g-name-owner (if the daemon disappears) */
}
/*
@@ -4551,6 +4577,9 @@ pk_client_get_progress_state_finish (PkClientState *state, const GError *error)
g_signal_handlers_disconnect_by_func (state->proxy,
G_CALLBACK (pk_client_signal_cb),
state);
+ g_signal_handlers_disconnect_by_func (state->proxy,
+ G_CALLBACK (pk_client_notify_name_owner_cb),
+ state);
g_object_unref (G_OBJECT (state->proxy));
}
--
2.30.2
From 7c5fbc921b83321f3e1e56fe24ab1d0840de35ab Mon Sep 17 00:00:00 2001
From: Philip Withnall <pwithnall@endlessos.org>
Date: Fri, 19 Mar 2021 22:51:01 +0000
Subject: [PATCH 2/2] packagekit-glib2: Cancel a transaction if calling Cancel
fails
If calling the `Cancel()` D-Bus method on a transaction fails, cancel
the client-side state anyway, to prevent the client from waiting forever
on a response which is unlikely to come.
Spotted in https://gitlab.gnome.org/GNOME/gnome-software/-/issues/1118.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
---
lib/packagekit-glib2/pk-client.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/lib/packagekit-glib2/pk-client.c b/lib/packagekit-glib2/pk-client.c
index 67df1c5ea..eba4ee47d 100644
--- a/lib/packagekit-glib2/pk-client.c
+++ b/lib/packagekit-glib2/pk-client.c
@@ -569,14 +569,18 @@ pk_client_cancel_cb (GObject *source_object,
gpointer user_data)
{
GDBusProxy *proxy = G_DBUS_PROXY (source_object);
+ PkClientState *state = user_data;
g_autoptr(GError) error = NULL;
g_autoptr(GVariant) value = NULL;
/* get the result */
value = g_dbus_proxy_call_finish (proxy, res, &error);
if (value == NULL) {
- /* there's not really a lot we can do here */
- g_warning ("failed to cancel: %s", error->message);
+ /* Instructing the daemon to cancel failed, so just return an
+ * error to the client so they don’t wait forever. */
+ g_debug ("failed to cancel: %s", error->message);
+ g_prefix_error (&error, "Failed to cancel: ");
+ pk_client_state_finish (state, error);
return;
}
}
@@ -600,7 +604,7 @@ pk_client_cancellable_cancel_cb (GCancellable *cancellable, PkClientState *state
G_DBUS_CALL_FLAGS_NONE,
PK_CLIENT_DBUS_METHOD_TIMEOUT,
NULL,
- pk_client_cancel_cb, NULL);
+ pk_client_cancel_cb, state);
}
/*
--
2.30.2
