Re: [Qemu-trivial] [PATCH] curses: don't initialize curses when qemu is daemonized

[Hitoshi Mitake]

On Fri, Sep 14, 2012 at 9:40 PM, Stefan Hajnoczi <address@hidden> wrote:
> On Fri, Sep 14, 2012 at 12:25 PM, Hitoshi Mitake <address@hidden> wrote:
>> On Fri, Sep 14, 2012 at 4:53 PM, Stefan Hajnoczi <address@hidden> wrote:
>>> On Wed, Sep 12, 2012 at 09:38:30PM +0900, Hitoshi Mitake wrote:
>>>> Current qemu initializes curses even if -daemonize option is
>>>> passed. This cause problem because shell prompt appears without
>>>> calling endwin().
>>>>
>>>> This patch adds new function, is_daemonized(), to OS dependent
>>>> code. With this function, curses_display_init() can check that qemu is
>>>> daemonized or not. If daemonized, curses_display_init() returns
>>>> immediately.
>>>>
>>>> Of course, -daemonize && -curses doesn't make sense. Users shouldn't
>>>> pass the arguments at the same time. But the problem is very painful
>>>> because Ctrl-C cannot be delivered to the terminal. So if this
>>>> approach isn't acceptable, -daemonize && -curses combination should be
>>>> treated as error.
>>>
>>> I think it makes sense to explicitly check that -daemonize is used with
>>> -nographic | -vnc | -spice.
>>
>> Yes. But -curses doesn't make sense when it is passed with -daemonize.
>>
>>>
>>> Making curses aware of daemonize seems strange and doesn't stop the same
>>> issue with SDL.
>>>
>>
>> What is the same issue with SDL?
>
> You are right, it's fine to have an SDL display when QEMU is daemonized.
>
> What bugged me about the patch is that ui/curses.c shouldn't know
> about daemonize.  It would be cleaner to check this before
> initializing the curses display.  An error could be printed instead of
> silently skipping curses initialization.
>
> Can you move the check to vl.c:main() so it calls is_daemonized() and
> exits with an error message?
>

I agree with moving is_daemonized() to main(). I'll include this change
in the next version.

But I'm worrying about the way of printing error message and exiting.
This may break scripts which execute qemu with -daemonize && -curses.

So I like the way of skipping initialization of curses silently.
It doesn't change the semantics of command line option of qemu.

I'd like to hear your comments.

Thanks,
Hitoshi