Permission Access Control List on unix system

[Decodetalkers]

Describe the bug

As you have seen , except 9 bits of permission, sometimes there are an extra permission , it is called extended permissions, and seems with the permission, every program will have the access to the folder, although they do not have any permission under the folder. and maybe it can be the enhancement of ls command

How to reproduce

1. plug the U board
2. Enter /run/media or other place it is mounted
3. /usr/bin/ls -la or try exa -la . you will see '+' if use ^ls, and @ if use exa

Expected behavior

the xattrs should be handled, related code of exa is in https://github.com/ogham/exa/blob/master/src/fs/fields.rs#L92

Screenshots

No response

Configuration

key	value
version	0.71.0
branch	makepkg
commit_hash	6cc4ef6
build_os	linux-x86_64
build_target	x86_64-unknown-linux-gnu
rust_version	rustc 1.65.0 (Arch Linux rust 1:1.65.0-1)
cargo_version	cargo 1.65.0
pkg_version	0.71.0
build_time	2022-11-09 06:34:03 +00:00
build_rust_channel	release
features	database, dataframe, default, trash, which, zip
installed_plugins

Additional context

No response

[Decodetalkers]

https://serverfault.com/questions/227852/what-does-a-mean-at-the-end-of-the-permissions-from-ls-l

I have found a relative discussion from serverfault

From arch wiki
https://wiki.archlinux.org/title/Access_Control_Lists

and the relatived crate https://docs.rs/xattr/latest/xattr/

[Decodetalkers]

Maybe ls can also use an extra table to show these information

[Decodetalkers]

But there are not much popular crates about ACLS..and exa also just know the folder is ACLS folder, and people do not always need to enter to the ACLS folder, they just need to enter into the mounted folder of device in it , and in the mounted folders, it will have the known permission. So I think maybe an other solution is to add -i to cd to force change directory 🤔

I don't know if show the message for ACLS is needed,but now exa and origin ls can know the message of such kind of folder. So..

[remmycat]

Hey @Decodetalkers 🙂
I ran into the issue of not being able to read xattrs from a different angle (macOS quarantine…)

I prepared a PR for a generic approach to read xattrs in ls, could you maybe have a look at it for feedback? #7158
(Does the PR solve this issue? What would you like to be different?)

[devurandom]

In addition to ACLs (getfacl), support for arbitrary extended attributes / xattrs (getfattr) would be nice.