[Libguestfs] [PATCH 3/4] tools: Use C API for inspection

[Matthew Booth]

On 28/10/10 12:37, Richard W.M. Jones wrote:
>> From 6e19d032d0d28e62f38223b6cc05dc36d9352add Mon Sep 17 00:00:00 2001
> From: Richard W.M. Jones<rjones at redhat.com>
> Date: Wed, 27 Oct 2010 16:06:11 +0100
> Subject: [PATCH 3/4] tools: Use C API for inspection (RHBZ#642930).
>
> Update the following tools to use the C API for inspection:
>
>   - virt-cat
>   - virt-edit
>   - virt-ls
>   - virt-tar
>   - virt-win-reg
>
> None of the tools in the tools/ directory now use the deprecated
> Perl inspection APIs.
> ---
>   tools/virt-cat     |   37 +++++++++++++++++--------------------
>   tools/virt-edit    |   35 ++++++++++++++++-------------------
>   tools/virt-ls      |   39 ++++++++++++++++++---------------------
>   tools/virt-tar     |   38 ++++++++++++++++++--------------------
>   tools/virt-win-reg |   39 ++++++++++++++++++---------------------
>   5 files changed, 87 insertions(+), 101 deletions(-)
>
> diff --git a/tools/virt-cat b/tools/virt-cat
> index 66806a1..546e85c 100755
> --- a/tools/virt-cat
> +++ b/tools/virt-cat
> @@ -157,22 +156,20 @@ if ($uri) {
>
>   $g->launch ();
>
> -# List of possible filesystems.
> -my @partitions = get_partitions ($g);
> -
> -# Now query each one to build up a picture of what's in it.
> -my %fses =
> -    inspect_all_partitions ($g, \@partitions,
> -      use_windows_registry =>  0);
> -
> -my $oses = inspect_operating_systems ($g, \%fses);
> -
> -my @roots = keys %$oses;
> -die __"multiboot operating systems are not supported by virt-cat" if @roots>  1;
> -my $root_dev = $roots[0];
> -
> -my $os = $oses->{$root_dev};
> -mount_operating_system ($g, $os);
> +my @roots = $g->inspect_os ();
> +if (@roots == 0) {
> +    die __x("{prog}: No operating system could be detected inside this disk image.\n\nThis may be because the file is not a disk image, or is not a virtual machine\nimage, or because the OS type is not understood by libguestfs.\n\nIf you feel this is an error, please file a bug report including as much\ninformation about the disk image as possible.\n",
> +            prog =>  basename ($0));
> +}
> +if (@roots>  1) {
> +    die __x("{prog}: multiboot operating systems are not supported.\n",
> +            prog =>  basename ($0))
> +}
> +my %fses = $g->inspect_get_mountpoints ($roots[0]);
> +my @fses = sort { length $a<=>  length $b } keys %fses;
> +foreach (@fses) {
> +    $g->mount_ro ($fses{$_}, $_);
> +}
>
>   # Allow this to fail in case eg. the file does not exist.
>   # NB:https://bugzilla.redhat.com/show_bug.cgi?id=501888

This is pretty long for boiler plate code which will be used in all the 
virt tools, including virt-v2v. This should live in a high-level library 
function which:

1. Inspects a guest.
2. Mounts all its storage, optionally read-only.

It wouldn't necessarily need to form part of a published API

Matt
-- 
Matthew Booth, RHCA, RHCSS
Red Hat Engineering, Virtualisation Team

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