Libguestfs - Apr 2014 - Re: [PATCH] virt-v2v: Catch invalid initrd path

In some cases (specifically, SUSE grub2 environments) it is possible to
fail to update the block entries in device.map. In turn, this causes an
invalid path to be returned in perl-Bootloader code, which causes the
conversion to fail with the following message:

is_file_opts: is_file: is_file_stub: path must start with a / character

This patch prevents the problem by adding device.map (for /boot/grub and
/boot/grub2) to the list of configurations to remap, then adds a check
to ensure invalid paths are not passed to is_file_opts.

Note - This is for the existing (perl version) of virt-v2v.

---
 lib/Sys/VirtConvert/Converter/Linux.pm | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/lib/Sys/VirtConvert/Converter/Linux.pm
b/lib/Sys/VirtConvert/Converter/Linux.pm
index e8463bc..b673120 100644
--- a/lib/Sys/VirtConvert/Converter/Linux.pm
+++ b/lib/Sys/VirtConvert/Converter/Linux.pm
@@ -56,7 +56,10 @@ sub get_initrd
         if (defined($initrd)) {
             # If the initrd starts with (hdX,X), remove it.
             $initrd =~ s/^\(hd.*\)//;
-            return $initrd if ($g->is_file_opts($initrd,
followsymlinks=>1));
+            # Catch invalid paths by ensuring first character is '/'
+            if ($initrd =~ /^\//) {
+                return $initrd if $g->is_file_opts($initrd,
followsymlinks=>1);
+            }
         }
     }
 
@@ -2672,13 +2675,13 @@ sub _remap_block_devices
 
         # Add standard configuration files to the checklist
         push (@checklist, '/files/etc/fstab/*/spec');
+        push (@checklist, '/files/boot/*/device.map/*'.
+                          '[label() != "#comment"]');
 
         # Add grub or grub2 files to the checklist
         if (defined($grub->{grub_conf})) {
             push (@checklist,
"/files$grub->{grub_conf}/*/kernel/root");
             push (@checklist,
"/files$grub->{grub_conf}/*/kernel/resume");
-            push (@checklist, '/files/boot/grub/device.map/*'.
-                              '[label() != "#comment"]');
         }
         elsif (defined($grub->{cfg})) {
             push (@checklist,
'/files/etc/sysconfig/grub/GRUB_CMDLINE_LINUX');
-- 
1.8.4.5

On Thu, Apr 24, 2014 at 04:43:59PM -0600, Mike Latimer
wrote:
> In some cases (specifically, SUSE grub2 environments) it is possible to
> fail to update the block entries in device.map. In turn, this causes an
> invalid path to be returned in perl-Bootloader code, which causes the
> conversion to fail with the following message:
> 
> is_file_opts: is_file: is_file_stub: path must start with a / character
> 
> This patch prevents the problem by adding device.map (for /boot/grub and
> /boot/grub2) to the list of configurations to remap, then adds a check
> to ensure invalid paths are not passed to is_file_opts.
> 
> Note - This is for the existing (perl version) of virt-v2v.
Sorry for the late reply, but I've been buried in the v2v rewrite for
the past few days.  I will take this patch into account when I get
back to the Linux conversion part.

Thanks,
Rich.
> ---
>  lib/Sys/VirtConvert/Converter/Linux.pm | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/Sys/VirtConvert/Converter/Linux.pm
b/lib/Sys/VirtConvert/Converter/Linux.pm
> index e8463bc..b673120 100644
> --- a/lib/Sys/VirtConvert/Converter/Linux.pm
> +++ b/lib/Sys/VirtConvert/Converter/Linux.pm
> @@ -56,7 +56,10 @@ sub get_initrd
>          if (defined($initrd)) {
>              # If the initrd starts with (hdX,X), remove it.
>              $initrd =~ s/^\(hd.*\)//;
> -            return $initrd if ($g->is_file_opts($initrd,
followsymlinks=>1));
> +            # Catch invalid paths by ensuring first character is
'/'
> +            if ($initrd =~ /^\//) {
> +                return $initrd if $g->is_file_opts($initrd,
followsymlinks=>1);
> +            }
>          }
>      }
>  
> @@ -2672,13 +2675,13 @@ sub _remap_block_devices
>  
>          # Add standard configuration files to the checklist
>          push (@checklist, '/files/etc/fstab/*/spec');
> +        push (@checklist, '/files/boot/*/device.map/*'.
> +                          '[label() != "#comment"]');
>  
>          # Add grub or grub2 files to the checklist
>          if (defined($grub->{grub_conf})) {
>              push (@checklist,
"/files$grub->{grub_conf}/*/kernel/root");
>              push (@checklist,
"/files$grub->{grub_conf}/*/kernel/resume");
> -            push (@checklist, '/files/boot/grub/device.map/*'.
> -                              '[label() !=
"#comment"]');
>          }
>          elsif (defined($grub->{cfg})) {
>              push (@checklist,
'/files/etc/sysconfig/grub/GRUB_CMDLINE_LINUX');
> -- 
> 1.8.4.5
> 
> _______________________________________________
> Libguestfs mailing list
> Libguestfs@redhat.com
> https://www.redhat.com/mailman/listinfo/libguestfs
-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v

On Friday, April 25, 2014 08:58:24 PM Richard W.M. Jones
wrote:
> Sorry for the late reply, but I've been buried in the v2v rewrite for
> the past few days.  I will take this patch into account when I get
> back to the Linux conversion part.
No problem. Thanks for looking at it.

Regarding the re-write, are you far enough long that patches to the perl 
version are no longer needed? Also, is virt-p2v on the rewrite list as well?

Thanks again,
Mike