[mythtv-users] External Channel Change Question? - WAS Re: CentOS and MythTV

[Brian Wood]

On Feb 12, 2006, at 8:33 PM, Kenneth Hadley wrote:

> Len Reed wrote:
>> Kenneth Hadley wrote:
>>
>>> Brian Wood wrote:
>>>
>>>> On Feb 12, 2006, at 7:02 PM, Kenneth Hadley wrote:
>>>>
>>>>> Appears I spoke too soon about have no further problems.
>>>>>
>>>>> I use a MyBlaster to control my external Samsung DirecTV  
>>>>> receiver and
>>>>> with my previous box this worked fine using the MyBlaster.pl  
>>>>> script.
>>>>>
>>>>> This time...not working so well.
>>>>>
>>>>> I have the script located in /usr/local/bin/ and typed into the  
>>>>> input
>>>>> field of "mythtvsetup=>input connections=>/dev/video0/=>External
>>>>> channel
>>>>> change command" the script path/filename (/usr/local/bin/ 
>>>>> MyBlaster.pl)
>>>>> but when I record programs the channel never changes and when  
>>>>> watching
>>>>> the MyBlaster transmitter when the recording starts and it  
>>>>> should be
>>>>> blinking, it does not.
>>>>>
>>>>> Manually typing at the CLI
>>>>> [mythtv at pvr01 ~]$ /usr/local/bin/MyBlaster.pl 298
>>>>> Does change the channel.
>>>>>
>>>>> Anyone have any thoughts?
>>>>>
>>>>> Thanks!
>>>>>
>>>>>
>>>> Probably the most common problem with scripts is that they have be
>>>> both readable and executable in order to work. Just a simple  
>>>> thing to
>>>> check.
>>>>
>>>>
>>> chmod +0777 /usr/local/bin/MyBlaster.pl
>>> chmod +x /usr/local/bin/MyBlaster.pl
>>>
>>
>> They don't, however, have to be world writable and it's bad  
>> practice --
>> even on a dedicated system on a safe LAN -- to make things world
>> writable.  0755 maybe, but not 0777.
>>
>> Are you running your command line test (which works) as the same user
>> that mythbackend is running?  This script will have to access some
>> device, which will also have permission issues if mythbackend isn't
>> running as root.
>>
>> Beware also if you're running mythbackend as setid root: perl may see
>> that real-user != effective user and try to run a taint-controlled
>> version.  That can be tricky to get working.
>>
>> Len
>>
> To be honest I have no idea what user the mythbackend is running as, I
> followed Jarod's guide substituting FC4 with CentOS (RHEL4). Is  
> there a
> way to find this out?
>

Sure, just run ps -aux | grep backend. The first column will tell you  
what user the process is running as.