posix-acl

posix-acl is a Rust library to interact with POSIX file system Access Control Lists (ACL). It wraps the operating system's C interface with a safe Rust API. The API is deliberately different from the POSIX C API to make it easier to use.

Only works on Linux. FreeBSD support seems viable as well, let me know if there is interest. macOS does not support POSIX ACLs sufficiently for this library.

Resources:

• Library API documentation on Docs.rs
• Background information about ACL behavior

Usage example

use posix_acl::{PosixACL, Qualifier, ACL_READ, ACL_WRITE};

fn main() {
    // Read ACL from file (if there is no ACL yet, the OS will synthesize one)
    let mut acl = PosixACL::read_acl("/tmp/posix-acl-testfile").unwrap();

    // Get permissions of owning user of the file
    let perm = acl.get(Qualifier::UserObj).unwrap();
    assert_eq!(perm, ACL_READ | ACL_WRITE);

    // Get permissions for user UID 1234
    let perm = acl.get(Qualifier::User(1234));
    assert!(perm.is_none());

    // Grant read access to group GID 1234 (adds new entry or overwrites an existing entry)
    acl.set(Qualifier::Group(1234), ACL_READ);

    // Remove ACL entry of group GID 1234
    acl.remove(Qualifier::Group(1234));

    // Write ACL back to the file
    acl.write_acl("/tmp/posix-acl-testfile").unwrap();
}

Release history

1.1.0 (2022-05-25)

• Added ACLError::as_io_error() method to access the underlying std::io::Error instance (#57)
• Minor: Documentation tweaks (#46)
• Minor: Clippy warnings fixed (#47, #49)
• Minor: CI/tests improvements (#44, #58)

1.0.0 (2020-03-30)

• API change: Now using ACLError structured error type instead of SimpleError (#39)

  Error messages from I/O calls no longer include the file name.

• The PosixACL::new() constructor no longer adds a Mask entry (#37)

  Mask is only needed for "non-minimal" ACLs and automatically is added on write if necessary.

• Major reorganization of code (#35)

• Documentation improvements

0.5.0 (2020-03-17)

• API change: Now using AsRef<Path> in methods that accept paths (read_acl etc.) (#33)

  This means .as_ref() is no longer needed or allowed when passing paths to these methods.

• Added methods into_raw, from_raw for converting to/from raw acl_t pointer (#21). Thanks to @aidanhs!

• Documentation tweaks & code cleanups

0.4.0 (2020-03-10)

This release is fully API-compatible with 0.3.0.

• Documentation expanded substantially (#27)
• Added read_default_acl() and write_default_acl() to interact with default ACLs of directories (#18, #30). Thanks to @aidanhs!
• PosixACL struct now implements the Debug trait (#24)
• Improved test coverage and CI workflow

0.3.0 (2020-02-20)

• Update 'acl-sys' and 'libc' dependencies (#14)

0.2.0 (2020-02-08)

• Add equality trait for PosixACL (#7)
• Use GitHub Actions & Docker for CI (#6)
• Add ACL remove() method
• Make ACLEntry fields public as intended

0.1.0 (2020-02-06)

• Initial release