[File] [PATCH] Add magic for Gentoo GLEP 78 (GPKG) binary packages

[Christos Zoulas]

Committed, thanks!

christos

> On Sep 5, 2022, at 7:47 AM, Michał Górny <mgorny at gentoo.org> wrote:
> 
> Add the basic magic for the new Gentoo binary package format introduced
> via GLEP 78.  The format uses an uncompressed .tar container that
> can easily be recognized by its first member being a file named
> "<directory>/gpkg-1".  The check additionally reports the compression
> used for the binary package members by looking at the second member's
> name.
> 
> The check currently works only if "-e tar" is used.  I would like to
> look into adding an appropriate logic for detecting the format
> in is_tar() and forcing the fallback to magic rules explicitly
> in the future.
> 
> An interesting extension would also be to add support for tar-style
> octal numbers in offset expressions, as that would make it possible
> to determine the offset of the second member metadata, and therefore
> determine whether the binary package is signed.
> ---
> magic/Magdir/archive | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
> 
> diff --git a/magic/Magdir/archive b/magic/Magdir/archive
> index df78791c..2aaa7310 100644
> --- a/magic/Magdir/archive
> +++ b/magic/Magdir/archive
> @@ -32,6 +32,9 @@
>>>>>>>>> 0	regex		\^[0-9]{2,4}[.](png|jpg|jpeg|tif|tiff|gif|bmp)
> #foo
>>>>>>>>>> 0	use	tar-cbt
> +# GPKG starts with <directory>/gpkg-1 file
> +>>>>>>>>0	search/100		/gpkg-1\0
> +>>>>>>>>>0	use	tar-gpkg
> # if 1st member name without digits and without used image suffix then it is a TAR archive
>>>>>>>>> 0	default		x
>>>>>>>>>> 0	use	tar-file
> @@ -169,6 +172,25 @@
> # or maybe like ComicInfo.xml
>> 0	string		>\0		\b, 1st image %-.60s
> 
> +# Summary:	Gentoo GLEP 78 binary package
> +# URL:		https://www.gentoo.org/glep/glep-0078.html
> +# Note:		assumes the strict format
> +0	name		tar-gpkg
> +>0	string		x		Gentoo GLEP 78 (GPKG) binary package
> +!:mime	application/x-tar
> +!:ext	tar
> +# the logic below requires the gpkg-1 file to be empty
> +>>124	string	00000000000\0
> +# determine the compression used by looking at the second member name
> +>>>512	search/100	.tar.
> +>>>>&0	string		gz\0		using gzip compression
> +>>>>&0	string		bz2\0		using bzip2 compression
> +>>>>&0	string		lz\0		using lzip compression
> +>>>>&0	string		lz4\0		using lz4 compression
> +>>>>&0	string		lzo\0		using lzo compression
> +>>>>&0	string		xz\0		using xz compression
> +>>>>&0	string		zst\0		using zstd compression
> +
> # Incremental snapshot gnu-tar format from:
> # https://www.gnu.org/software/tar/manual/html_node/Snapshot-Files.html
> 0	string		GNU\ tar-	GNU tar incremental snapshot data
> --
> 2.37.3
> 
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