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systemd-logind: Monitor systemd-logind going away

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When we're using server managed-fds through systemd-logind, systemd-logind
*must* keep running while we are using it, as it does things like drmSetMaster
and drmDropMaster for us on vt-switch.

On a systemd-logind restart, we cannot simply re-connect since we will then
get a different fd for the /dev/dri/card# node, and we've tied a lot of
state to the old fd. I've discussed this with the systemd people, and in the
future there may be a restart mechanism were systemd-logind passed fds from
the old logind to the new logind. But for now there answer is simply:
"Don't restart systemd-logind", and there never really is a good reason to
restart it.

So to ensure unpleasentness if people do decide to restart systemd-logind
anyways (or when it crashes), monitor logind going away and make this a fatal
error. This avoids getting a hard-hung machine on the next vt-switch and will
hopefully quickly educate users to not restart systemd-logind while they have
an X session using it active.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
This commit is contained in:
Hans de Goede 2014-03-24 16:32:01 +01:00 committed by Peter Hutterer
parent c0d3a13e7e
commit dc48bd653c
1 changed files with 32 additions and 2 deletions
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34
hw/xfree86/os-support/linux/systemd-logind.c
View File

@ -310,11 +310,32 @@ message_filter(DBusConnection * connection, DBusMessage * message, void *data)
dbus_int32_t major, minor;
char *pause_str;
dbus_error_init(&error);
if (dbus_message_is_signal(message,
"org.freedesktop.DBus", "NameOwnerChanged")) {
char *name, *old_owner, *new_owner;
dbus_message_get_args(message, &error,
DBUS_TYPE_STRING, &name,
DBUS_TYPE_STRING, &old_owner,
DBUS_TYPE_STRING, &new_owner, DBUS_TYPE_INVALID);
if (dbus_error_is_set(&error)) {
LogMessage(X_ERROR, "systemd-logind: NameOwnerChanged: %s\n",
error.message);
dbus_error_free(&error);
return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
}
if (name && strcmp(name, "org.freedesktop.login1") == 0)
FatalError("systemd-logind disappeared (stopped/restarted?)\n");
return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
}
if (strcmp(dbus_message_get_path(message), info->session) != 0)
return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
dbus_error_init(&error);
if (dbus_message_is_signal(message, "org.freedesktop.login1.Session",
"PauseDevice")) {
if (!dbus_message_get_args(message, &error,
@ -472,6 +493,15 @@ connect_hook(DBusConnection *connection, void *data)
goto cleanup;
}
dbus_bus_add_match(connection,
"type='signal',sender='org.freedesktop.DBus',interface='org.freedesktop.DBus',member='NameOwnerChanged',path='/org/freedesktop/DBus'",
&error);
if (dbus_error_is_set(&error)) {
LogMessage(X_ERROR, "systemd-logind: could not add match: %s\n",
error.message);
goto cleanup;
}
/*
* HdG: This is not useful with systemd <= 208 since the signal only
* contains invalidated property names there, rather than property, val