Evaluating a port to RTEMS (embedded OS with single address space and no processes)

[Christian Mauderer]

Am 04.02.2016 um 17:42 schrieb Shinose:
> 
> On Thu, Feb 4, 2016 at 7:49 PM, Christian Mauderer
> <christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>> wrote:
> 
>     Am 04.02.2016 um 14:46 schrieb Roland Mainz:
>     > On Thu, Feb 4, 2016 at 1:40 PM, Christian Mauderer
>     > <christian.mauderer at embedded-brains.de
>     <mailto:christian.mauderer at embedded-brains.de>> wrote:
>     >> I am searching a SSH server for remote administration of an embedded
>     >> application running on RTEMS (https://www.rtems.org). This environment
>     >> has neither virtual memory nor user and kernel space. So this is like an
>     >> application running in kernel mode only.
>     >>
>     >> Would it be possible to run (a very basic version of) OpenSSH in such an
>     >> environment using e.g. threads instead of forking new subprocesses? Is
>     >> there already some known similar configuration (e.g. on another embedded
>     >> OS)?
>     >
>     > Well, not much harder than a port to the original m68k AmigaOS or most
>     > of the military-oriented embedded OSes... not hard but lots of work
>     > (unless you have an existing POSIX(-like) layer emulation), mostly
>     > related to resource tracking and the socket stuff.
>     >
> 
>     Hello Roland,
> 
>     thanks for the quick answer. I must have overlooked these ports. I have
>     mostly seen the list of full Unixes on this page:
> 
>       http://www.openssh.com/portable.html
> 
>     After your hint, I noted that there are a lot more ports in the sources.
>     Is there some kind of porting guide or a hint where to begin reading
>     documentation?
> 
>     If we would create a port: Would it be theoretically possible to
>     contribute it to the official sources?
> 
>     For the POSIX-layer: RTEMS implements a part of the POSIX standard (or
>     at least of the embedded subset of POSIX). But like I said it doesn't
>     have processes but only threads.
> 
>     Kind Regards
> 
>     Christian Mauderer 
> 
> 
> Hi,
> 
> We have successfully ported OpenSSH along with SFTP-Server for a
> Greenhills platform, where it was only having single address space and
> threads.
> 
> But I could say it was really a painful work to resolve the global
> variables and data structures to each threads.
> 
> We have used a total of 3 threads including the SFTP Server.
> 
> Thanks,
> Shinose.


Hello Shinose,

thanks for your feedback. It's good to know that it is possible and
someone has already done something similar.

Kind regards

Christian Mauderer

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