Bug 62910

Right now weston-launch and weston cooperate to shut down cleanly.  Weston catches SIGSEGV and SIGABRT and cleans up as best as it can with help from weston-launch.  So killing weston is fine and should work, though SIGKILL can't be caught and doesn't let weston shut down nicely, so that will lock up the system.  Killing weston-launch isn't something we've tried to make work well and it will leave weston hanging trying to read from the socket to weston-launch while having the system stuck with keyboard disabled.

So in short, don't kill weston-launch, kill weston.  weston-launch now returns exit codes to reflect how weston exited: 0 means all is well, 10+signal means weston dies from signal and 128+signal means that weston-launch itself took a signal.

In the future, I think we'll  move some of the "dangerous stuff" out of weston and into weston-launcher.  Things like vt switch and disabling kb and switching the console into graphics mode may be better done in launcher so that no matter how weston dies, weston-launch can always clean it up.  When we do that, we'll also teach weston-launch to clean up properly when it itself crashes.

Appreciate the insights. Thanks, krh!

(In reply to comment #1)
> So in short, don't kill weston-launch, kill weston.  weston-launch now
> returns exit codes to reflect how weston exited: 0 means all is well,
> 10+signal means weston dies from signal and 128+signal means that
> weston-launch itself took a signal.
> 
> In the future, I think we'll  move some of the "dangerous stuff" out of
> weston and into weston-launcher.  Things like vt switch and disabling kb and
> switching the console into graphics mode may be better done in launcher so
> that no matter how weston dies, weston-launch can always clean it up.  When
> we do that, we'll also teach weston-launch to clean up properly when it
> itself crashes.

I think catching SIGTERM and doing nothing (or perhaps printing a message) when launched by weston-launch might be helpful.

commit 1a81abb1ddb3fdc02a344624bef74710e31c0b73
Author: Kristian Høgsberg <krh@bitplanet.net>
Date:   Mon Jun 17 15:23:20 2013 -0400

    weston-launch: Don't exit on SIGTERM
    
    Instead, forward signal to weston and wait for weston to clean up nicely.
    Weston relies on weston-launch being around to shut down correctly,
    so don't exit until we get the SIGCHLD from weston.  This make
    killall weston-launch work properly.
    
    https://bugs.freedesktop.org/show_bug.cgi?id=62910

Almost there! When I killall weston-launch, with either SIGINT or SIGTERM, get the following:

libwayland: error marshalling arguments for leave (signature uo): null value passed for arg 1

I'm in the process of tracking down what's breaking, but when I attach to desktop-shell prior to killing, gdb registers a segv.

(In reply to comment #4)
> commit 1a81abb1ddb3fdc02a344624bef74710e31c0b73
> Author: Kristian Høgsberg <krh@bitplanet.net>
> Date:   Mon Jun 17 15:23:20 2013 -0400
> 
>     weston-launch: Don't exit on SIGTERM
>     
>     Instead, forward signal to weston and wait for weston to clean up nicely.
>     Weston relies on weston-launch being around to shut down correctly,
>     so don't exit until we get the SIGCHLD from weston.  This make
>     killall weston-launch work properly.
>     
>     https://bugs.freedesktop.org/show_bug.cgi?id=62910

That's unrelated, it's a different bug that Jason Ekstrand is working on a fix for.  As for the segv, this might be the fix:

diff --git a/clients/window.c b/clients/window.c
index c13d207..c1ea0ec 100644
--- a/clients/window.c
+++ b/clients/window.c
@@ -1522,7 +1522,7 @@ window_destroy(struct window *window)
 
        wl_list_for_each(input, &display->input_list, link) {
                if (input->pointer_focus == window)
-                       input->pointer_focus = NULL;
+                       input_remove_pointer_focus(input);
                if (input->keyboard_focus == window)
                        input->keyboard_focus = NULL;
                if (input->focus_widget &&

If you have time to check it out, that'd be cool.

(In reply to comment #5)
> Almost there! When I killall weston-launch, with either SIGINT or SIGTERM,
> get the following:
> 
> libwayland: error marshalling arguments for leave (signature uo): null value
> passed for arg 1
> 

The error message above is already being tracked at https://bugs.freedesktop.org/show_bug.cgi?id=65726

Since the commit does fix the issue originally reported, I'll mark 'verified'. The issue identified in comment #5 will be addressed in another filing.