Re: [Xenomai] rt_task_create fails when running over ssh

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On 11/04/2012 05:43 PM, Andrey Nechypurenko wrote:

> On 4 November 2012 17:30, Gilles Chanteperdrix
> <gilles.chanteperdrix@xenomai.org> wrote:
>> On 11/04/2012 05:13 PM, Andrey Nechypurenko wrote:
>>
>>> On 3 November 2012 22:34, Gilles Chanteperdrix
>>> <gilles.chanteperdrix@xenomai.org> wrote:
>>>> On 11/03/2012 10:32 PM, Andrey Nechypurenko wrote:
>>>>
>>>>>> Use the DESTDIR environment variable (you can look inside xeno-config to
>>>>>> see how it works, it should be pretty obvious).
>>>>>
>>>>> Thanks for the hint. I'll definitely try. However I doubt that it
>>>>> would solve the issue with rt_task_create() since I were actually
>>>>> copy-pasting the output from xeno-config and only change the -I and -L
>>>>> flags to reflect my directory structure.
>>>>
>>>>
>>>> Yes, I also doubt that very much. What about the arm/thumb issue?
>>>
>>> I've run strace and found the following line in the output when
>>> starting the programm over ssh:
>>> sched_setscheduler(440, SCHED_FIFO, { 99 }) = -1 EPERM (Operation not permitted)
>>> I assume, that this call is the part of rt_task_create(). In contrast,
>>> the same call gets no errors if running in the serial console. Really
>>> strange to me.
>>>
>>> My attempts to change corresponding priorities with ulimit command or
>>> setrlimit() function does not solve the issue. So it seams like ssh
>>> server limits some permissions somehow which causes rt_task_create()
>>> to fail.
> 
>> Did you check if your compiler compiles thumb code or arm code by default?
> 
> objdump says: file format elf32-littlearm
> and file says: ELF 32-bit LSB executable, ARM, version 1 (SYSV)


The result is the same with thumb code. In order to know if a binary is
thumb or arm, run objdump and check if the binary contains 16 bits
instructions.

> 
>> You can run ulimit to check the current limits.
>> And it would be interesting to run the "whoami" command or use getuid()
>> in the program to check whether you are really running as the root user.
> 
> $ ulimit -a


What about whoami or id (it would be nice if did not have to ask the
same questions 3 times)?

I have 0 for scheduling priority and real-time priority, and it does not
seem to cause any issue.

-- 
                                                                Gilles.