Extracting FreeBSD kernel tarball creates /boot/kernel/GNUSparseFile.0/kernel

[rwp0]

Extracting FreeBSD kernel tarball compressed with XZ renames

./boot/kernel/kernel to ./boot/kernel/GNUSparseFile.0/kernel

which means contains_file and extract_file methods no longer work with file not found error.

https://download.freebsd.org/ftp/releases/amd64/13.1-RELEASE/kernel.txz

Testing with:

use v5.32; use Archive::Tar;
say for Archive::Tar -> new('/opt/13.1/kernel.txz') -> list_files;

and tar tf '/opt/13.1/kernel.txz' we get the following difference:

422c422
< ./boot/kernel/kernel
---
> ./boot/kernel/GNUSparseFile.0/kernel

while both bsdtar and gtar (GNU tar) can list and extract

# tar --version
bsdtar 3.4.2 - libarchive 3.4.2 zlib/1.2.11 liblzma/5.2.5 bz2lib/1.0.8 

# gtar --version
tar (GNU tar) 1.34

---

I've installed the following FreeBSD packages before running A:T, of course (for XZ support):

• p5-Archive-Tar: 2.40
• p5-Compress-Raw-Bzip2: 2.101
• p5-Compress-Raw-Lzma: 2.101
• p5-Compress-Raw-Zlib: 2.101
• p5-IO-Compress: 2.101
• p5-IO-Compress-Lzma: 2.101
• p5-IO-String: 1.08_1

There's some info on sparse files, but I don't understand what is it, and what makes A:T do that while the CLI utilities list and extract properly.

https://www.gnu.org/software/tar/manual/html_section/Sparse-Formats.html
https://www.gnu.org/software/tar/manual/html_node/Sparse-Recovery.html

---

using Perl version 5.32.0

[h3xx]

It also extracts to the wrong path, creating boot/kernel/GNUSparseFile.0/kernel whereas gnu tar creates boot/kernel/kernel.

Searching thru that particular archive, I see:

...^@^@^@^@^@^@^@^@^@27 mtime=1652339437.749802
22 GNU.sparse.major=1
22 GNU.sparse.minor=0
40 GNU.sparse.name=./boot/kernel/kernel
32 GNU.sparse.realsize=29343680
...^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@./boot/kernel/GNUSparseFile.0/kernel^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@000555 ^@000000 ^@000000 ^@00157340700 14237131355 017533^@ 0^@^@...

Where ^@ is less(1)'s representation of NUL.

This makes me think this was created with a version of tar that is using an older version of tar's sparse file format.