chcpu exit code?

chcpu exit code?

[Bernhard Voelker]

Although the man page does not mention the exit status, I think
it's wrong that 'chcpu' exits OK when an action failed or
when a bad CPU number was specified:

   $ ./chcpu -d 0 ; echo $?
   CPU 0 is not hot pluggable
   0

   $ ./chcpu -g 3 ; echo $?
   CPU 3 is not configurable
   0

   $ ./chcpu -e 4 ; echo $?
   CPU 4 does not exist
   0

WDYT?

Have a nice day,
Berny

Re: chcpu exit code?

[Dale R. Worley]

> From: Bernhard Voelker <mail@bernhard-voelker.de>
> 
> Although the man page does not mention the exit status, I think
> it's wrong that 'chcpu' exits OK when an action failed or
> when a bad CPU number was specified:

> WDYT?

I agree that it would be helpful if chcpu used the usual
success/failure convention for exit status.  The reason is that
sometimes one wants to use "set -e" in a script so that any command
that fails unexpectedly will cause processing to halt.  Similarly, if
one hands a command to a program to execute, a program that is set up
to execute generic commands supplied by some outside source usually
handles non-zero exit status specially by reporting that the command
failed, while treating zero exit statuses as not-to-be-remarked-upon.

Dale

Re: chcpu exit code?

[Heiko Carstens]

On Thu, Feb 27, 2014 at 10:46:26AM +0100, Bernhard Voelker wrote:
> Although the man page does not mention the exit status, I think
> it's wrong that 'chcpu' exits OK when an action failed or
> when a bad CPU number was specified:
> 
>   $ ./chcpu -d 0 ; echo $?
>   CPU 0 is not hot pluggable
>   0
> 
>   $ ./chcpu -g 3 ; echo $?
>   CPU 3 is not configurable
>   0
> 
>   $ ./chcpu -e 4 ; echo $?
>   CPU 4 does not exist
>   0
> 
> WDYT?

The question is: what should chcpu return if it partially succeeded?

# chcpu -d 3-4
CPU 3 disabled
CPU 4 does not exist

If I remember correctly this was the reason to make it always return 0.

However, it is indeed valid to say if *everything* failed, it should
return an error. Hm?

Re: chcpu exit code?

[Bernhard Voelker]

On 02/28/2014 08:53 AM, Heiko Carstens wrote:
> The question is: what should chcpu return if it partially succeeded?
>
> # chcpu -d 3-4
> CPU 3 disabled
> CPU 4 does not exist
>
> If I remember correctly this was the reason to make it always return 0.
>
> However, it is indeed valid to say if *everything* failed, it should
> return an error. Hm?

Indeed, e.g. df(1) also fails if only a single mount point
cannot be listed.  Otherwise, the calling script could not rely
on the exit code, and would still have to fall back to parsing
the output.

But thanks to your question I was reminded to have a look
at *where* chcpu writes messages:

   $ chcpu -d 3-4 > /dev/null
   $ chcpu -d 3-4 2> /dev/null
   CPU 3 is already disabled
   CPU 4 does not exist
   $

I.e. chcpu does not write the error diagnostic to stderr ... humm.

Have a nice day,
Berny

Re: chcpu exit code?

[Karel Zak]

On Fri, Feb 28, 2014 at 08:53:55AM +0100, Heiko Carstens wrote:
> On Thu, Feb 27, 2014 at 10:46:26AM +0100, Bernhard Voelker wrote:
> > Although the man page does not mention the exit status, I think
> > it's wrong that 'chcpu' exits OK when an action failed or
> > when a bad CPU number was specified:
> > 
> >   $ ./chcpu -d 0 ; echo $?
> >   CPU 0 is not hot pluggable
> >   0
> > 
> >   $ ./chcpu -g 3 ; echo $?
> >   CPU 3 is not configurable
> >   0
> > 
> >   $ ./chcpu -e 4 ; echo $?
> >   CPU 4 does not exist
> >   0
> > 
> > WDYT?
> 
> The question is: what should chcpu return if it partially succeeded?
> 
> # chcpu -d 3-4
> CPU 3 disabled
> CPU 4 does not exist

 This is not so unusual situation, we have for example the same thing
 in mount -a where

   0 - success
  32 - mount failure
  64 - some mount succeeded

I think we can do something like this with chcpu, my suggestion is

   0 - success
   1 - failure
  64 - partial success

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: chcpu exit code?

[Bernhard Voelker]

On 02/28/2014 10:04 AM, Karel Zak wrote:
> I think we can do something like this with chcpu, my suggestion is
>
>     0 - success
>     1 - failure
>    64 - partial success

+1

Thanks & have a nice day,
Berny

Re: chcpu exit code?

[Karel Zak]

On Mon, Mar 03, 2014 at 12:23:27PM +0100, Bernhard Voelker wrote:
> On 02/28/2014 10:04 AM, Karel Zak wrote:
> >I think we can do something like this with chcpu, my suggestion is
> >
> >    0 - success
> >    1 - failure
> >   64 - partial success
> 
> +1

 Fixed. Thanks for your report.

    Karel
-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: chcpu exit code?

[Bernhard Voelker]

On 03/05/2014 11:12 AM, Karel Zak wrote:
>   Fixed. Thanks for your report.

LGTM, thanks!

Have a nice day,
Berny