blob: 48084aa23dd82ff4d004591819fafd411e7ee26d [file] [log] [blame]
/*
* Copyright (C) 2021 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
use log::error;
use nix::sys::stat::{mode_t, Mode, SFlag};
use std::io;
use super::VirtFdService;
/// Default/assumed mode of files not created by authfs.
///
/// For files that are given to authfs as FDs (i.e. not created through authfs), their mode is
/// unknown (or untrusted) until it is ever set. The default mode is just to make it
/// readable/writable to VFS. When the mode is set, the value on fd_server is supposed to become
/// consistent.
const DEFAULT_FILE_MODE: Mode =
Mode::from_bits_truncate(Mode::S_IRUSR.bits() | Mode::S_IWUSR.bits());
/// Default/assumed mode of directories not created by authfs.
///
/// See above.
const DEFAULT_DIR_MODE: Mode = Mode::S_IRWXU;
/// `Attr` maintains the local truth for attributes (e.g. mode and type) while allowing setting the
/// remote attribute for the file description.
pub struct Attr {
service: VirtFdService,
mode: Mode,
remote_fd: i32,
is_dir: bool,
}
impl Attr {
pub fn new_file(service: VirtFdService, remote_fd: i32) -> Attr {
Attr { service, mode: DEFAULT_FILE_MODE, remote_fd, is_dir: false }
}
pub fn new_dir(service: VirtFdService, remote_fd: i32) -> Attr {
Attr { service, mode: DEFAULT_DIR_MODE, remote_fd, is_dir: true }
}
pub fn new_file_with_mode(service: VirtFdService, remote_fd: i32, mode: mode_t) -> Attr {
Attr { service, mode: Mode::from_bits_truncate(mode), remote_fd, is_dir: false }
}
pub fn new_dir_with_mode(service: VirtFdService, remote_fd: i32, mode: mode_t) -> Attr {
Attr { service, mode: Mode::from_bits_truncate(mode), remote_fd, is_dir: true }
}
pub fn mode(&self) -> u32 {
self.mode.bits()
}
/// Sets the file mode.
///
/// In addition to the actual file mode, `encoded_mode` also contains information of the file
/// type.
pub fn set_mode(&mut self, encoded_mode: u32) -> io::Result<()> {
let new_sflag = SFlag::from_bits_truncate(encoded_mode);
let new_mode = Mode::from_bits_truncate(encoded_mode);
let type_flag = if self.is_dir { SFlag::S_IFDIR } else { SFlag::S_IFREG };
if !type_flag.contains(new_sflag) {
return Err(io::Error::from_raw_os_error(libc::EINVAL));
}
// Request for update only if changing.
if new_mode != self.mode {
self.service.chmod(self.remote_fd, new_mode.bits() as i32).map_err(|e| {
error!(
"Failed to chmod (fd: {}, mode: {:o}) on fd_server: {:?}",
self.remote_fd, new_mode, e
);
io::Error::from_raw_os_error(libc::EIO)
})?;
self.mode = new_mode;
}
Ok(())
}
}