[Buildroot] [PATCH 1/2] modem-manager: fix test of unset variable in init script

[Yann E. MORIN <yann.morin.1998@free.fr>]

Thomas, All,

On 2018-04-15 20:18 +0200, Thomas Petazzoni spake thusly:
> On Sun, 15 Apr 2018 12:31:49 -0300 (BRT), Carlos Santos wrote:
> > >> +MODEMMANAGER_BIN=/usr/sbin/ModemManager
> > >>  PIDFILE=/var/run/ModemManager.pid
> > >>  
> > >>  [ -x $MODEMMANAGER_BIN ] || exit 0  
> > > 
> > > In fact, I think this test doesn't make sense. It just exits without
> > > any error if the binary doesn't exists, which is silly.
> > > 
> > > I'm advocating for removing such tests altogether, which would make the
> > > MODEMMANAGER_BIN variable unnecessary.  
> > 
> > I think the original purpose of these test was allowing the user to
> > disable the service by chmod'ing -x the executable file. We discussed
> > a similar situation in
> > 
> >    https://patchwork.ozlabs.org/patch/818897/
> > 
> > [which by the way is still in my endless to-do list]
> 
> Well, if you look at my feedback on this patch, I was already saying
> that the test to check whether radvd was executable or not was not
> useful.
> 
> I don't think making a binary program non-executable as a way of
> disabling its startup at boot time is very common. Probably a
> ENABLED=true/false variable in /etc/default/<service> is more common.
> 
> So, I think we should remove all those [ -x /usr/sbin/<foo> ] checks in
> our init scripts.
> 
> Cc'ing Peter, Arnout and Yann to gather additional opinions on this.

I agree with Thomas.

This is a position we already stated quite a few times in the past.

If one does not want the daemon, then just remove it and the init script
from a post-build script. If it is about debugging, just remove the
startup script on the target, or just 'exit 0' at the top of it.

Regards,
Yann E. MORIN.

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