Ответ: Chat applet started

[Denys Vlasenko]

[CC:ed to busybox again]
[please do not remove CC when you reply]

On Tuesday 12 February 2008 12:20, Vladimir Dronnikov wrote:
> Although I will conform BB style just say me "Why?!"

Because otherwise CONFIG_WERROR=y build will not work.

I am not a big fan of this, but there are people
who feels strongly about "C is not C++!". Let's respect them.

> +       // setup signals
> > +       sig_catch(SIGHUP,  signal_handler);
> > +       sig_catch(SIGINT,  signal_handler);
> > +       sig_catch(SIGTERM, signal_handler);
> > +       sig_catch(SIGPIPE, signal_handler);
> >
> > This is an unfair question, but:
> > And why not SIGQUIT? SIGABRT? SIGALRM? SIGXCPU?
> > Why do you need to catch signals? To ensure that you reset back
> > the tcsetattr?
> 
> Yes! Because in BB it's deprecated to use atexit().
> Even if an applet is not NOFORK one.
> We _have to_ restore tty state.

atext would not help here, either.

atexit will not be run if you have some fatal signal
set to SIG_DFL. If fatal signal is set to SIG_DFL,
it works exactly like SIGKILL - *blamm!!* and process
doesn't exist anymore; kernel cleans up after it
(reuses memory, closes file descriptors and so on).
No atexit runs.

I guess we need

bb_signals(int signals_bitmask, handler);

which can be used like this:

	bb_signals(0
         + (1 << SIGHUP)
         + (1 << SIGINT)
         + (1 << SIGTERM)
         + (1 << SIGPIPE)
         + (1 << SIGQUIT)
         + (1 << SIGABRT)
         + (1 << SIGALRM)
         + (1 << SIGXCPU)
	 , signal_handler);

to install handler for many signals.
--
vda