Re: [fuse-devel] how to register a exit handler

[Hans B. <han...@gm...>]

The problem was never to get hold of the fuse object handle. The
problem was how to modify the exit callback in struct fuse_session_ops
without having to use the fuse_lowlevel API. The fuse_session_ops
structure is "hidden" and its definition only available through
fuse_i.h, which is not part of the API itself.
But knowing how the struct was declared I could hack around it. But in
the end I actually did not have to ;) Using the provided API to
register signal handlers was enough. For some reason it did not work
when I tried the first time, but after some more testing (and also
checking the implementation which is very straight forward) I came to
the conclusion that my non-interruptable process was caused by
something else. And it was, I still do not know why, but it works fine
now.

Thanks.

Hans



2011/6/15  <the...@gm...>:
> On Tue, Jun 14, 2011 at 2:06 AM, Hans Beckérus <han...@gm...> wrote:
>> On 2011-06-14 1:42, the...@gm... wrote:
>> I do have unmount and clean-up code after my event loops stops. But the
>> problem is not when the event loop is
>> stopped in a controlled fashion. I need to call fuse_exit() also for eg.
>> SIGINT (CTRL-C).
>> Registering my own signal handler for SIGINT could solve that, but then
>> I do not know how to easily propagate the struct fuse*  to be able to
>> call fuse_exit() for the correct instance. That is why I want to
>> register a exit handler instead on session level using the
>> fuse_session_ops::exit.
>> But I can not find a suitable API function that can do that? And I do
>> not want to go through fuse_create_session() which means I need to start
>> using the fuse_lowlevel API.
>
> You do not need to use the fuse low level APIs to get to the struct
> fuse. You will not be able to use fuse_main() but you could use
> fuse_setup() or fuse_new(), which both return the struct fuse for the
> instance. You would then need to start the main loop. Before starting
> the main loop you could save the struct fuse in a static variable that
> your sighandler has access to.
>
> BTW fuse_new() will require you to do more setup which is handled by
> fuse_setup for you, but fuse_setup does call
> fuse_set_signal_handlers().
>
>>>> I tried to use fuse_set_signal_handlers() but that just made things
>>>> worse :( Then I could not even break out of the foreground process using
>>>> CTRL-C.
>>>>
>> Hmm, actually this was not working as expected. Using a *very* dirty
>> trick I managed to register my own exit handler in fuse_session_ops
>> (that is why I need some help doing it the proper way). Then if I also
>> call fuse_set_signal_handlers() and just leave the exit handler empty,
>> fuse_exit() is called automatically at SIGINT and my event loop
>> terminates nicely. But, If I do not register a exit handler and only
>> call fuse_set_signal_handlers()  SIGINT does not work, eg. fuse_exit()
>> is never called and clean-up is not possible! This I can not explain.
>
> This is strange since the fuse signal handlers for the most part just
> call fuse_exit().
>
> -nate
>