fd_server: use RwLock instead of Mutex
`nix::dir::Dir` isn't Sync (required by `RwLock`), so I had to replace
it with `OwnedFd`.
Bug: 220386264
Test: atest AuthFsHostTest
Test: performance change before vs after is hard to tell
Change-Id: Ib3fd9047970a856b532234f0bebad652172e12de
diff --git a/authfs/fd_server/src/aidl.rs b/authfs/fd_server/src/aidl.rs
index 2975aa4..3a3cdb2 100644
--- a/authfs/fd_server/src/aidl.rs
+++ b/authfs/fd_server/src/aidl.rs
@@ -17,7 +17,7 @@
use anyhow::Result;
use log::error;
use nix::{
- dir::Dir, errno::Errno, fcntl::openat, fcntl::OFlag, sys::stat::fchmod, sys::stat::mkdirat,
+ errno::Errno, fcntl::openat, fcntl::OFlag, sys::stat::fchmod, sys::stat::mkdirat,
sys::stat::mode_t, sys::stat::Mode, sys::statvfs::statvfs, sys::statvfs::Statvfs,
unistd::unlinkat, unistd::UnlinkatFlags,
};
@@ -29,8 +29,9 @@
use std::os::unix::fs::FileExt;
use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
use std::path::{Component, Path, PathBuf, MAIN_SEPARATOR};
-use std::sync::{Arc, Mutex};
+use std::sync::{Arc, RwLock};
+use crate::common::OwnedFd;
use crate::fsverity;
use authfs_aidl_interface::aidl::com::android::virt::fs::IVirtFdService::{
BnVirtFdService, FsStat::FsStat, IVirtFdService, MAX_REQUESTING_DATA,
@@ -63,21 +64,21 @@
ReadWrite(File),
/// A read-only directory to serve by this server.
- InputDir(Dir),
+ InputDir(OwnedFd),
/// A writable directory to serve by this server.
- OutputDir(Dir),
+ OutputDir(OwnedFd),
}
pub struct FdService {
/// A pool of opened files and directories, which can be looked up by the FD number.
- fd_pool: Arc<Mutex<BTreeMap<i32, FdConfig>>>,
+ fd_pool: Arc<RwLock<BTreeMap<i32, FdConfig>>>,
}
impl FdService {
pub fn new_binder(fd_pool: BTreeMap<i32, FdConfig>) -> Strong<dyn IVirtFdService> {
BnVirtFdService::new_binder(
- FdService { fd_pool: Arc::new(Mutex::new(fd_pool)) },
+ FdService { fd_pool: Arc::new(RwLock::new(fd_pool)) },
BinderFeatures::default(),
)
}
@@ -88,7 +89,7 @@
where
F: FnOnce(&FdConfig) -> BinderResult<R>,
{
- let fd_pool = self.fd_pool.lock().unwrap();
+ let fd_pool = self.fd_pool.read().unwrap();
let fd_config = fd_pool.get(&id).ok_or_else(|| new_errno_error(Errno::EBADF))?;
handle_fn(fd_config)
}
@@ -99,7 +100,7 @@
where
F: FnOnce(&mut FdConfig) -> BinderResult<(i32, FdConfig)>,
{
- let mut fd_pool = self.fd_pool.lock().unwrap();
+ let mut fd_pool = self.fd_pool.write().unwrap();
let fd_config = fd_pool.get_mut(&fd).ok_or_else(|| new_errno_error(Errno::EBADF))?;
let (new_fd, new_fd_config) = create_fn(fd_config)?;
if let btree_map::Entry::Vacant(entry) = fd_pool.entry(new_fd) {
@@ -319,14 +320,12 @@
FdConfig::OutputDir(_) => {
let mode = validate_file_mode(mode)?;
mkdirat(dir_fd, basename, mode).map_err(new_errno_error)?;
- let new_dir = Dir::openat(
- dir_fd,
- basename,
- OFlag::O_DIRECTORY | OFlag::O_RDONLY,
- Mode::empty(),
- )
- .map_err(new_errno_error)?;
- Ok((new_dir.as_raw_fd(), FdConfig::OutputDir(new_dir)))
+ let new_dir_fd =
+ openat(dir_fd, basename, OFlag::O_DIRECTORY | OFlag::O_RDONLY, Mode::empty())
+ .map_err(new_errno_error)?;
+ // SAFETY: new_dir_fd is just created and not an error.
+ let fd_owner = unsafe { OwnedFd::from_raw_fd(new_dir_fd) };
+ Ok((new_dir_fd, FdConfig::OutputDir(fd_owner)))
}
_ => Err(new_errno_error(Errno::ENOTDIR)),
})
@@ -336,7 +335,7 @@
validate_basename(basename)?;
self.handle_fd(dir_fd, |config| match config {
- FdConfig::OutputDir(_dir) => {
+ FdConfig::OutputDir(_) => {
unlinkat(Some(dir_fd), basename, UnlinkatFlags::NoRemoveDir)
.map_err(new_errno_error)?;
Ok(())
@@ -350,7 +349,7 @@
validate_basename(basename)?;
self.handle_fd(dir_fd, |config| match config {
- FdConfig::OutputDir(_dir) => {
+ FdConfig::OutputDir(_) => {
unlinkat(Some(dir_fd), basename, UnlinkatFlags::RemoveDir)
.map_err(new_errno_error)?;
Ok(())