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

[Carlos Santos <casantos@datacom.ind.br>]

> From: "Thomas Petazzoni" <thomas.petazzoni@bootlin.com>
> To: "Carlos Santos" <casantos@datacom.ind.br>
> Cc: "buildroot" <buildroot@buildroot.org>, "Aleksander Morgado" <aleksander@aleksander.es>
> Sent: Saturday, April 14, 2018 1:07:25 PM
> Subject: Re: [Buildroot] [PATCH 1/2] modem-manager: fix test of unset variable in init script

> Hello,
> 
> On Fri, 13 Apr 2018 13:25:20 -0300, Carlos Santos wrote:
>> MODEMMANAGER_BIN was never set. Fortunately it did not break the script
>> execution due to the permissive behavior of "test":
>> 
>>     $ test -x non-existing || echo error
>>     error
>>     $ test -x  || echo error
>>     test -x && echo success
>>     success
>> 
>> Signed-off-by: Carlos Santos <casantos@datacom.ind.br>
>> ---
>>  package/modem-manager/S44modem-manager | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>> 
>> diff --git a/package/modem-manager/S44modem-manager
>> b/package/modem-manager/S44modem-manager
>> index cf6d89601d..05803fe198 100755
>> --- a/package/modem-manager/S44modem-manager
>> +++ b/package/modem-manager/S44modem-manager
>> @@ -3,6 +3,7 @@
>>  # Starts ModemManager
>>  #
>>  
>> +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]

-- 
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