[Xenomai-core] Re: iovec overwriting by CAN stack

[Jan Kiszka <jan.kiszka@domain.hid>]

[-- Attachment #1: Type: text/plain, Size: 1141 bytes --]

Wolfgang Grandegger wrote:
> Jan Kiszka wrote:
>> Hi Wolfgang,
>>
>> it's late, so I may have misread somecode, but don't you "update" the
>> iovec descriptors a user passes on send/recvmsg on return (namely
>> iovec_len)? I received some complaints about this /wrt to in-kernel CAN
>> stack usage.
> 
> It's done here:
> 
> http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/drivers/can/rtcan_raw.c?v=SVN-trunk#881
> 
> http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/drivers/can/rtcan_raw.c?v=SVN-trunk#734
> 
> 
> I may have missed something. What are the real complaints? Is there a
> test program?

Not yet (will commit the related patch to our RACK likely later today).
It's simply sending frames while re-using the msg+iovec structs in a loop.

> 
>> I always considered the same well-know behaviour of RTnet a bug, but now
>> I found your code is doing this systematically, also for user space
>> callers. Is this behaviour undefined or even required according POSIX or
>> whatever?
> 
> I don't know, it's Sebastian's Kode.
> 

Hmm, hope he will not say that he imitated RTnet...

Jan


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 250 bytes --]