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

[Carlos Santos]

> From: "Yann E. MORIN" <yann.morin.1998 at free.fr>
> To: "Thomas Petazzoni" <thomas.petazzoni at bootlin.com>
> Cc: "Carlos Santos" <casantos at datacom.ind.br>, "buildroot" <buildroot at buildroot.org>, "Aleksander Morgado"
> <aleksander at aleksander.es>, "Peter Korsgaard" <peter at korsgaard.com>, "Arnout Vandecappelle" <arnout at mind.be>
> Sent: Sunday, April 15, 2018 3:58:28 PM
> Subject: Re: [Buildroot] [PATCH 1/2] modem-manager: fix test of unset variable in init script

> 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.

So I will prepare a series removing the tests from the startup scripts.

-- 
Carlos Santos (Casantos) - DATACOM, P&D
“The greatest triumph that modern PR can offer is the transcendent 
success of having your words and actions judged by your reputation, 
rather than the other way about.” — Christopher Hitchens