starnix_core/vfs/
xattr.rs

1// Copyright 2022 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5use crate::vfs::{FsStr, FsString, XattrOp, XattrStorage};
6use starnix_rcu::rcu_hash_map::Entry;
7use starnix_rcu::{RcuHashMap, RcuReadScope};
8use starnix_sync::RcuHashMapLock;
9use starnix_uapi::errors::Errno;
10use starnix_uapi::{errno, error};
11
12pub struct MemoryXattrStorage {
13    // Arbitrary userspace programs can define xattr keys so we use a collision-resistant hasher.
14    xattrs:
15        RcuHashMap<FsString, Box<[u8]>, RcuHashMapLock, std::collections::hash_map::RandomState>,
16}
17
18impl Default for MemoryXattrStorage {
19    fn default() -> Self {
20        Self { xattrs: RcuHashMap::with_hasher(std::collections::hash_map::RandomState::new()) }
21    }
22}
23
24impl XattrStorage for MemoryXattrStorage {
25    fn get_xattr(&self, name: &FsStr) -> Result<Box<[u8]>, Errno> {
26        self.xattrs.get(&RcuReadScope::new(), name).cloned().ok_or_else(|| errno!(ENODATA))
27    }
28
29    fn set_xattr(&self, name: &FsStr, value: &[u8], op: XattrOp) -> Result<(), Errno> {
30        let mut xattrs = self.xattrs.lock();
31        match xattrs.entry(name.to_owned()) {
32            Entry::Vacant(_) if op == XattrOp::Replace => return error!(ENODATA),
33            Entry::Occupied(_) if op == XattrOp::Create => return error!(EEXIST),
34            Entry::Vacant(v) => {
35                v.insert(value.into());
36            }
37            Entry::Occupied(mut o) => {
38                o.insert(value.into());
39            }
40        };
41        Ok(())
42    }
43
44    fn remove_xattr(&self, name: &FsStr) -> Result<(), Errno> {
45        let mut xattrs = self.xattrs.lock();
46        if xattrs.remove(name).is_none() {
47            return error!(ENODATA);
48        }
49        Ok(())
50    }
51
52    fn list_xattrs(&self) -> Result<Vec<FsString>, Errno> {
53        Ok(self.xattrs.keys(&RcuReadScope::new()).cloned().collect())
54    }
55}
starnix_core/vfs/xattr.rs

starnix_core/vfs/
xattr.rs
