[Libguestfs] [PATCH] customize: firstboot: make sure to run Linux scripts only once

[Richard W.M. Jones]

On Mon, Nov 03, 2014 at 08:49:08PM +0100, Pino Toscano wrote:
> If a script does not finish, hangs, etc, it would be executed again at
> the next boot, since the injected firstboot.sh helper removes it only
> after it finished.
> 
> Since firstboot.sh only runs executable files, then remove the
> executable attributes before running it, so it will not run again.
> Also, remove any file found in the scripts subdirectory, be it just run
> or run in a previous boot.
> 
> This fixes RHBZ#1159651.
> ---
>  customize/firstboot.ml | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/customize/firstboot.ml b/customize/firstboot.ml
> index 67b9479..5f68a2e 100644
> --- a/customize/firstboot.ml
> +++ b/customize/firstboot.ml
> @@ -57,10 +57,13 @@ then
>    for f in $d/* ; do
>      if test -x \"$f\"
>      then
> +      # remove +x from the script being executed, so it is not
> +      # executed again at the next boot
> +      chmod -x $f
>        echo '=== Running' $f '===' 2>&1 | tee $logfile
> -      $f 2>&1 | tee $logfile
> -      rm -f $f
> +      sh $f 2>&1 | tee $logfile

I like the idea .. unfortunately I believe this will make it run the
wrong interpreter.  eg. If the firstboot script started with
'#!/usr/bin/perl' then this would run it with 'sh' instead.

I'm not sure how to work around that.  'env' maybe?

Is it better to document the problem instead?  Arguably this bug is
user error.  Perhaps they'd be better off doing something like:

  ( sleep 10 ; reboot ) &

at the end of their script.

Rich.

>      fi
> +    rm -f $f
>    done
>  fi
>  " firstboot_dir
> -- 
> 1.9.3
> 
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-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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