Re: [PATCH 2/2] wic: Add --embed-rootfs argument

[Paul Barker <pbarker@konsulko.com>]

On Wed,  4 Mar 2020 09:34:38 +0100
Ricardo Ribalda Delgado <ricardo@ribalda.com> wrote:

> This option adds the content of a rootfs on a specific location on the
> rootfs.
> 
> It is very useful for making a partition that contains the rootfs for a
> host and a target Eg:
> 
> / -> Roofs for the host
> /export/ -> Rootfs for the target (which will netboot)
> 
> Although today we support making a partition for "/export" this might
> not be compatible with some upgrade systems, or we might be limited by
> the number of partitions.
> 
> With this patch we can use something like:
> 
> part / --source rootfs --embed-rootfs=target-image:/export

I considered using a syntax like this for --include-path but I chose not to
as it's not easy to choose a separator. ':' is a valid character in a
directory name.

My approach is to handle this in two steps:

1) Add a new task before do_image_wic which creates an 'embedded-rootfs'
  directory and copies 'target-image' to 'embedded-rootfs/export'.

2) Use '--include-path=embedded-rootfs' in the wks file.

> 
> on the .wks file.
> 
> Signed-off-by: Ricardo Ribalda Delgado <ricardo@ribalda.com>
> ---
>  scripts/lib/wic/help.py                  |  7 +++++++
>  scripts/lib/wic/ksparser.py              |  1 +
>  scripts/lib/wic/partition.py             |  1 +
>  scripts/lib/wic/plugins/source/rootfs.py | 20 +++++++++++++++++++-
>  4 files changed, 28 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/lib/wic/help.py b/scripts/lib/wic/help.py
> index 4d342fcf05..67a33e6a65 100644
> --- a/scripts/lib/wic/help.py
> +++ b/scripts/lib/wic/help.py
> @@ -979,6 +979,13 @@ DESCRIPTION
>                           copies. This option only has an effect with the rootfs
>                           source plugin.
>  
> +         --embed-rootfs: This option is specific to wic. It embeds a rootfs into
> +                         the given path to the resulting image. The option
> +                         contains two fields, the roofs and the path, separated
> +                         by a colon. The rootfs follows the same logic as the
> +                         rootfs-dir argument. This option only has an effect
> +                         with the rootfs source plugin.
> +
>           --extra-space: This option is specific to wic. It adds extra
>                          space after the space filled by the content
>                          of the partition. The final size can go
> diff --git a/scripts/lib/wic/ksparser.py b/scripts/lib/wic/ksparser.py
> index 650b976223..d422e2a6bb 100644
> --- a/scripts/lib/wic/ksparser.py
> +++ b/scripts/lib/wic/ksparser.py
> @@ -138,6 +138,7 @@ class KickStart():
>          part.add_argument('--align', type=int)
>          part.add_argument('--exclude-path', nargs='+')
>          part.add_argument('--include-path', nargs='+')
> +        part.add_argument('--embed-rootfs', nargs='+')
>          part.add_argument("--extra-space", type=sizetype)
>          part.add_argument('--fsoptions', dest='fsopts')
>          part.add_argument('--fstype', default='vfat',
> diff --git a/scripts/lib/wic/partition.py b/scripts/lib/wic/partition.py
> index 2d95f78439..13857df82f 100644
> --- a/scripts/lib/wic/partition.py
> +++ b/scripts/lib/wic/partition.py
> @@ -31,6 +31,7 @@ class Partition():
>          self.extra_space = args.extra_space
>          self.exclude_path = args.exclude_path
>          self.include_path = args.include_path
> +        self.embed_rootfs = args.embed_rootfs
>          self.fsopts = args.fsopts
>          self.fstype = args.fstype
>          self.label = args.label
> diff --git a/scripts/lib/wic/plugins/source/rootfs.py b/scripts/lib/wic/plugins/source/rootfs.py
> index 40419a64b3..16359601dc 100644
> --- a/scripts/lib/wic/plugins/source/rootfs.py
> +++ b/scripts/lib/wic/plugins/source/rootfs.py
> @@ -80,7 +80,7 @@ class RootfsPlugin(SourcePlugin):
>  
>          new_rootfs = None
>          # Handle excluded paths.
> -        if part.exclude_path or part.include_path:
> +        if part.exclude_path or part.include_path or part.embed_rootfs:
>              # We need a new rootfs directory we can delete files from. Copy to
>              # workdir.
>              new_rootfs = os.path.realpath(os.path.join(cr_workdir, "rootfs%d" % part.lineno))
> @@ -100,6 +100,24 @@ class RootfsPlugin(SourcePlugin):
>              for path in part.include_path or []:
>                  copyhardlinktree(path, new_rootfs)
>  
> +            for embed in part.embed_rootfs or []:
> +                [embed_rootfs, path] = embed.split(":")
> +                #we need to remove the initial / for os.path.join to work
> +                if os.path.isabs(path):
> +                    path = path[1:]
> +                if embed_rootfs in krootfs_dir:
> +                    embed_rootfs = krootfs_dir[embed_rootfs]
> +                embed_rootfs = cls.__get_rootfs_dir(embed_rootfs)
> +                tar_file = os.path.realpath(os.path.join(cr_workdir, "aux.tar"))
> +                tar_cmd = "%s tar cpf %s -C %s ." % (cls.__get_pseudo(native_sysroot,
> +                                                     embed_rootfs), tar_file, embed_rootfs)
> +                exec_native_cmd(tar_cmd, native_sysroot)
> +                untar_cmd = "%s tar xf %s -C %s ." % (cls.__get_pseudo(native_sysroot, new_rootfs),
> +                                                      tar_file, os.path.join(new_rootfs, path))
> +                exec_native_cmd(untar_cmd, native_sysroot,
> +                                cls.__get_pseudo(native_sysroot, new_rootfs))
> +                os.remove(tar_file)
> +

Why are you using an intermediate tar file here?

>              for orig_path in part.exclude_path or []:
>                  path = orig_path
>                  if os.path.isabs(path):



-- 
Paul Barker
Konsulko Group