RFE: mksquashfs via tar stream/pipe

[gmkurtzer]

I see that there was a request for this in SF (https://sourceforge.net/p/squashfs/feature-requests/14/), but wanted to bring up an additional use case which I feel is very valuable.

Tarballs are being used as a portable format for container mobility, it would be very useful if a non-privileged user could pipe the tar contents directly into a squashFS file system in such a manner to avoid having to be root.

I realize that the contents could be splat out to a temporary directory structure but this is not only IO inefficient, it also can break privileged permissions (e.g. SUID) and ownership of the squashed files (even when --all-root, because not all files within a root file system are root owned).

Thank you!

[goertzenator]

An additional application is to exploit tar's superior file selection options. An actual limitation I ran into this: From a read-only root-owned source containing...

/nix/store/0000/
/nix/store/0001/
/nix/store/0002/
...
/nix/store/9999/

...I want just the following in my squashfs...

/nix/store/1234/
/nix/store/8888/

If I mksquashfs /nix/store/1234 /nix/store/8888 result.squashfs I get the wrong result...

1234/
8888/

But tar does this correctly: tar -cf result.tar /nix/store/1234 /nix/store/8888. It also provides all kinds of features to slice and dice paths.

Ultimately what I really want is...

tar -cf - /nix/store/1234 /nix/store/8888 | mksquashfs result.squashfs

[mattst88]

tar2sqfs and sqfs2tar are provided by squashfs-tools-ng. Works great in my testing.

[Dr-Emann]

This is fixed by the introduction of the sqfstar command in squashfs-tools 4.5

@plougher, Apologies for necro-ing this issue, I know you're super busy.

[plougher]

This been fixed since the Squashfs-tools 4.5 release, with the Sqfstar command.

e.g.

tar -cf - /nix/store/1234 /nix/store/8888 | sqfstar result.squashfs