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tools::acl: Add helpers to create extended attribute buffer.

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This helpers are used to construct the extended attributes values from
the ACLs stored in the pxar archive.

Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
This commit is contained in:
Christian Ebner 2020-01-28 12:42:22 +01:00 committed by Wolfgang Bumiller
parent bcf0d452c9
commit 0502ce6da3
1 changed files with 44 additions and 0 deletions
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44
src/tools/acl.rs
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@ -13,6 +13,8 @@ use std::ptr;
use libc::{c_char, c_int, c_uint, c_void};
use nix::errno::Errno;
// from: acl/include/acl.h
pub const ACL_UNDEFINED_ID: u32 = 0xffffffff;
// acl_perm_t values
pub type ACLPerm = c_uint;
pub const ACL_READ: ACLPerm = 0x04;
@ -38,6 +40,12 @@ pub const ACL_TYPE_DEFAULT: ACLType = 0x4000;
pub const ACL_FIRST_ENTRY: c_int = 0;
pub const ACL_NEXT_ENTRY: c_int = 1;
// acl to extended attribute names constants
// from: acl/include/acl_ea.h
pub const ACL_EA_ACCESS: &'static str = "system.posix_acl_access";
pub const ACL_EA_DEFAULT: &'static str = "system.posix_acl_default";
pub const ACL_EA_VERSION: u32 = 0x0002;
#[link(name = "acl")]
extern "C" {
fn acl_get_file(path: *const c_char, acl_type: ACLType) -> *mut c_void;
@ -285,3 +293,39 @@ pub fn mode_group_to_acl_permissions(mode: u64) -> u64 {
pub fn mode_other_to_acl_permissions(mode: u64) -> u64 {
mode & 7
}
/// Buffer to compose ACLs as extended attribute.
pub struct ACLXAttrBuffer {
buffer: Vec<u8>,
}
impl ACLXAttrBuffer {
/// Create a new buffer to write ACLs as extended attribute.
///
/// `version` defines the ACL_EA_VERSION found in acl/include/acl_ea.h
pub fn new(version: u32) -> Self {
let mut buffer = Vec::new();
buffer.extend_from_slice(&version.to_le_bytes());
Self { buffer }
}
/// Add ACL entry to buffer.
pub fn add_entry(&mut self, tag: ACLTag, qualifier: Option<u64>, permissions: u64) {
self.buffer.extend_from_slice(&(tag as u16).to_le_bytes());
self.buffer.extend_from_slice(&(permissions as u16).to_le_bytes());
match qualifier {
Some(qualifier) => self.buffer.extend_from_slice(&(qualifier as u32).to_le_bytes()),
None => self.buffer.extend_from_slice(&ACL_UNDEFINED_ID.to_le_bytes()),
}
}
/// Length of the buffer in bytes.
pub fn len(&self) -> usize {
self.buffer.len()
}
/// Borrow raw buffer as mut slice.
pub fn as_mut_slice(&mut self) -> &mut [u8] {
self.buffer.as_mut_slice()
}
}