From dc48bd653c7e1013e2d69e3f59ae3cbc0c893473 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Mon, 24 Mar 2014 16:32:01 +0100 Subject: [PATCH] systemd-logind: Monitor systemd-logind going away 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 Signed-off-by: Peter Hutterer Reviewed-by: Peter Hutterer --- hw/xfree86/os-support/linux/systemd-logind.c | 34 ++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/hw/xfree86/os-support/linux/systemd-logind.c b/hw/xfree86/os-support/linux/systemd-logind.c index 62858b062..ed670a88c 100644 --- a/hw/xfree86/os-support/linux/systemd-logind.c +++ b/hw/xfree86/os-support/linux/systemd-logind.c @@ -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