[Libguestfs] [PATCH] Fix detection of an existing grub entry

[Richard W.M. Jones]

On Thu, Jan 20, 2011 at 05:27:13PM +0000, Matthew Booth wrote:
> There were 2 issues in the code which checked for an existing grub entry before
> adding a new one.
> 
> Firstly, it didn't take account of the fact that the passed-in kernel path is
> relative to root, whereas the grub entry is relative to the grub filesystem,
> which is normally /boot.
> 
> Secondly, it expected return from inside eval{} to exit the function, when in
> fact it only exits the eval.
> ---
>  lib/Sys/VirtV2V/Converter/RedHat.pm |   16 +++++++---------
>  1 files changed, 7 insertions(+), 9 deletions(-)
> 
> diff --git a/lib/Sys/VirtV2V/Converter/RedHat.pm b/lib/Sys/VirtV2V/Converter/RedHat.pm
> index 0a4f829..d8f9141 100644
> --- a/lib/Sys/VirtV2V/Converter/RedHat.pm
> +++ b/lib/Sys/VirtV2V/Converter/RedHat.pm
> @@ -1500,23 +1500,21 @@ sub _check_grub
>  {
>      my ($version, $kernel, $g, $desc) = @_;
>  
> +    my $grubfs = $desc->{boot}->{grub_fs};
> +    my $prefix = $grubfs eq '/boot' ? '' : '/boot';
> +
>      # Nothing to do if there's already a grub entry
> -    eval {
> +    return if eval {
>          foreach my $augpath
>              ($g->aug_match('/files/boot/grub/menu.lst/title/kernel'))
>          {
> -            return if ($g->aug_get($augpath) eq $kernel);
> +            return 1 if ($grubfs.$g->aug_get($augpath) eq $kernel);
>          }
> +
> +        return 0
>      };
>      augeas_error($g, $@) if ($@);
>  
> -    my $prefix;
> -    if ($desc->{boot}->{grub_fs} eq "/boot") {
> -        $prefix = '';
> -    } else {
> -        $prefix = '/boot';
> -    }
> -
>      my $initrd = "$prefix/initrd-$version.img";
>      $kernel =~ m{^/boot/(.*)$} or die("kernel in unexpected location: $kernel");
>      my $vmlinuz = "$prefix/$1";

ACK.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org