From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Thu, 13 Jun 2013 06:23:23 +0200
From: Jan Kiszka <jan.kiszka@siemens.com>
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Subject: Re: [Xenomai] [PATCH] posix: Skip auto-shadowing if current thread
 is already shadowed
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To: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Cc: Xenomai <xenomai@xenomai.org>

On 2013-06-13 06:21, Jan Kiszka wrote:
> On 2013-06-12 13:06, Gilles Chanteperdrix wrote:
>> On 06/12/2013 08:15 AM, Jan Kiszka wrote:
>>
>>> While the user can also avoid double shadowing by providing the
>>> XENO_NOSHADOW environment variable, there is still no reason to attempt
>>> auto-shadowing in their absence if the current thread is already a
>>> Xenomai thread. This helps, e.g., in complex dlopen scenarios where
>>> the POSIX lib is pulled in belatedly, potentially after some other lib
>>> already shadowed the dlopen caller.
>>
>>
>> Well, last time I checked, calling __wrap_pthread_setschedparam for an
>> already shadowed threads was a nop.
> 
> I'm getting an EBUSY from xnshadow_map as called by __pthread_shadow.
> And that, of course, lets the lib init code bail out.

BTW, the test pattern is pretty simple:

main()
{
	...
	rt_task_shadow(&task, "test", 0, 0);
	handle = dlopen("libpthread_rt.so", RTLD_LAZY);
	...
}

Jan

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