Issues when adding a multi-port PCI serial card

[dufault at hda.com]

> On Mar 13, 2020, at 16:49 , Chris Johns <chrisj at rtems.org> wrote:
> 
> On 14/3/20 6:16 am, dufault at hda.com wrote:
>>> On Mar 13, 2020, at 08:42 , Sebastian Huber <sebastian.huber at embedded-brains.de> wrote:
>>>> Finally, after initial successful loop-back testing, I tried to start an RTEMS shell on one of the new ports.
>>>> 
>>>> *Here I'm trying hard to avoid all-caps because this took the most time of all (it should have been easiest), and I gave up!*
>>>> 
>>>> * HOW (sorry) do you spawn a shell on a serial port?  The documentation, at https://docs.rtems.org/branches/master/shell/configuration_and_init.html that suggests just setting the shell device name to "/dev/console", or in my case "/dev/ttyS9", is incorrect.  The shell startup is intent on using "stdin" and "stdout".
> 
> I am guessing it is a bug. I tripped over some issues ...
> 
> https://devel.rtems.org/ticket/3859
> 
>>> I don't know this off hand.
>> 
>> I don't need the shell spawned on one of the added serial ports.  I thought it would be an easy way to test the driver, but it isn't.  Obviously the "telnet" daemon does some monkeying around with "stdin" and "stdout" in order that it works via telnet.
> 
> A serial port should work with just the paths. You should also be able to do the
> same method as telnet and assign open descriptors then call the shell's main loop.
> 
>> * It would be great if it worked but I'm not going to investigate it.
> 
> I wonder if the issues you see are part of what I have fixed with ..
> 
> https://lists.rtems.org/pipermail/devel/2020-February/057422.html
> 
> The patch has not been pushed. I have pushed the changes to the 4.11 branch and
> I am planing to update the master version this week.
> 
> Chris

That looks very promising.  But what does this part mean?  Is it that anything that is a shell environment should have the unique magic number derived from "rtems_build_name" that evaluates to SENV?  So all shell environments will have the magic number SENV?  If I interpret that correctly it is pretty paranoid for a structure that is passed as part of initialization, where corruption isn't that common.

+  if (shell_env->magic != rtems_build_name('S', 'E', 'N', 'V')) {
+    rtems_error(0, "invalid shell environment passed to the main loop)");


Peter
-----------------
Peter Dufault
HD Associates, Inc.      Software and System Engineering

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