Exacl

Rust library to manipulate file system access control lists (ACL) on macOS, Linux, and FreeBSD.

Example

use exacl::{getfacl, setfacl, AclEntry, Perm};

// Get the ACL from "./tmp/foo".
let mut acl = getfacl("./tmp/foo", None)?;

// Print the contents of the ACL.
for entry in &acl {
    println!("{entry}");
}

// Add an ACL entry to the end.
acl.push(AclEntry::allow_user("some_user", Perm::READ, None));

// Set the ACL for "./tmp/foo".
setfacl(&["./tmp/foo"], &acl, None)?;

Benefits

• Supports the Posix ACL's used by Linux and FreeBSD.
• Supports the extended ACL's used by macOS and FreeBSD/NFSv4.
• Supports reading/writing of ACL's as delimited text.
• Supports serde (optional) for easy reading/writing of ACL's to JSON, YAML and other common formats.

API

This module provides two high level functions, getfacl and setfacl.

• getfacl retrieves the ACL for a file or directory.
• setfacl sets the ACL for files or directories.

On Linux and FreeBSD, the ACL contains entries for the default ACL, if present.

Both getfacl and setfacl work with a Vec<AclEntry>. The AclEntry structure contains five fields:

• kind : AclEntryKind - the kind of entry (User, Group, Other, Mask, or Unknown).

• name : String - name of the principal being given access. You can use a user/group name, decimal uid/gid, or UUID (on macOS).

• perms : Perm - permission bits for the entry.

• flags : Flag - flags indicating whether an entry is inherited, etc.

• allow : bool - true if entry is allowed; false means deny. Linux only supports allow=true.

More Examples

Here are some more examples showing how to use the library.

Get an ACL in common delimited string format:

    let acl = exacl::getfacl("/tmp/file", None)?;
    let result = exacl::to_string(&acl)?;

Get an ACL in JSON format:

    let acl = exacl::getfacl("/tmp/file", None)?;
    let result = serde_json::to_string(&acl)?;

Create a linux ACL for permissions that allow the owning user and group to read/write a file but no one else except for "fred".

    let mut acl = exacl::from_mode(0o660);
    acl.push(AclEntry::allow_user("fred", Perm::READ | Perm::WRITE, None));
    exacl::setfacl(&["/tmp/file"], &acl, None)?;

Create a linux ACL for directory permissions that gives full access to the owning user and group and read-only access to members of the accounting group. Any sub-directories created should automatically have the same ACL (via the default ACL).

    let mut acl = exacl::from_mode(0o770);
    acl.push(AclEntry::allow_group(
        "accounting",
        Perm::READ | Perm::EXECUTE,
        None,
    ));

    // Make default_acl a copy of access_acl with the DEFAULT flag set.
    let mut default_acl: Vec<AclEntry> = acl.clone();
    for entry in &mut default_acl {
        entry.flags |= Flag::DEFAULT;
    }
    acl.append(&mut default_acl);
    
    exacl::setfacl(&["./tmp/dir"], &acl, None)?;

Build and Test

On Linux, you must install the libacl1-dev package to build exacl. The integration tests require shunit2 which can be installed via apt or homebrew.

sudo apt install libacl1-dev shunit2

To run the unit tests with debug logging, type: RUST_LOG=debug cargo test

To run the integration tests, type:

cargo test --features serde; ./tests/run_tests.sh

Bindgen Feature

If there is a problem building exacl on your system, try enabling the bindgen feature.

cargo test --features bindgen