Delete protected task?

[Joel Sherrill <joel@OARcorp.com>]

Smith, Gene wrote:
> 
> Joel Sherrill <joel at OARcorp.com> wrote, On 1/18/2005 10:06 AM:
> 
>> Smith, Gene wrote:
>>
>>> Does rtems have the ability to set a task as delete protected? I 
>>> can't find this in manual. Specifically, looking for something 
>>> analogous to this:
>>>
>>> http://www.roe.ac.uk/atc/projects/vista/software/VxWorks/docs/vxworks/ref/taskLib.html#taskSafe 
>>
>>
>>
>>
>> No.  It doesn't.
>>
>> Off the top of my head, I don't see how to implement it without
>> changes to at least an API but a better solution would be in the
>> score.
>>
> 
> I am not an expert on rtems internals but it seem like to me one way for 
> a task to set itself delete protected would be using rtems_task_mode() 
> and define a new mode RTEMS_NO_DELETE. This could be used internally in 
> rtems to fail any call to rtems_task_delete() if set. However, the thing 
> about the deleting task blocking on rtems_task_delete() sound a lot more 
> complex.
> 
> I looked in the cpukit/score/src area and see lots of thread*.c files. 
> Is this approximately where you think this feature could be added?

Yes on first glance.

Another slightly different approach would be to start a library of these
calls.  Then you could have a VxWorks per thread context associated
with each thread.  Have a "nestable delete mutex" with each thread and 
lock that when a task is "safe from delete."

The trick to the above would be to implicitly create a VxWorks context
the first time a thread calls a VxWorks routine requiring one.

You seem to be creeping in this direction one call at a time anyway.
How many routines have you already worked through?

> -gene
> 
> 
> 


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