Re: [PATCH v9] testpmd: cleanup cleanly from signal

[Stephen Hemminger <stephen@networkplumber.org>]

On Mon, 30 Jan 2023 18:48:25 +0000
Ferruh Yigit <ferruh.yigit@amd.com> wrote:

> On 1/25/2023 6:32 PM, Stephen Hemminger wrote:
> > Do a clean shutdown of testpmd when a signal is received; instead of
> > having testpmd kill itself.  This fixes the problem where a signal could
> > be received in the middle of a PMD and then the signal handler would
> > call PMD's close routine leading to locking problems.
> > 
> > An added benefit is it gets rid of some Windows specific code.
> > 
> > Fixes: d9a191a00e81 ("app/testpmd: fix quitting in container")
> > Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>  
> 
> Patch looks good to me, but './devtools/test-null.sh' hangs with change.
> 
> It is possible the fix by updating './devtools/test-null.sh', but my
> concern is if this behavior change hit more consumers other than this
> internal tool, and I am for keeping previous behavior.
> 
> './devtools/test-null.sh' sends 'stop' command to testpmd but that seems
> not really what makes testpmd quit, because following change still works
> with original testpmd code:
>  -(sleep 1 && echo stop) |
>  +(sleep 1 && echo help) |
> Somehow testpmd gets Ctrl-D or equivalent with above command.
> 
> And it seems because of 'cmdline_interact()' and 'cmdline_poll()'
> difference behavior changes with above command.
> 
> It is possible to add something like  'cmdline_interact_one()' (non loop
> version of 'cmdline_interact()'), but not really sure that is correct
> way to fix the issue.
> 

Thanks for the review.
Fixed the end-of-file handling in v10 of the patch.
The cmdline_poll() function doesn't handle EOF correctly.

The function cmdline_poll() documentation is problematic since it
references that the return value is an enum, but the enum is actually
private and not exported by the library!