Implement root directory as a ReadonlyDirectory
This makes the handling in `lookup` consistent without having to deal
with inode 1 as a special case.
AuthFs is now initialized outside of fusefs module, in order to allow
the caller to add named entries to the filesystem's root directory more
directly.
The `ReadonlyDirectory` can also be used later to support remote
readonly directory.
Bug: 203251769
Test: atest AuthFsHostTest
Change-Id: Ia27f7f3c2f39d48559c329f6a086408745fbc3d9
diff --git a/authfs/src/file/remote_dir.rs b/authfs/src/file/dir.rs
similarity index 75%
rename from authfs/src/file/remote_dir.rs
rename to authfs/src/file/dir.rs
index d311b93..2eaaddd 100644
--- a/authfs/src/file/remote_dir.rs
+++ b/authfs/src/file/dir.rs
@@ -14,12 +14,12 @@
* limitations under the License.
*/
-use std::collections::HashMap;
+use std::collections::{hash_map, HashMap};
use std::io;
use std::path::{Path, PathBuf};
use super::remote_file::RemoteFileEditor;
-use super::{VirtFdService, VirtFdServiceStatus};
+use super::{validate_basename, VirtFdService, VirtFdServiceStatus};
use crate::fsverity::VerifiedFileEditor;
use crate::fusefs::Inode;
@@ -104,7 +104,8 @@
fn validate_argument(&self, basename: &Path) -> io::Result<()> {
// Kernel should only give us a basename.
- debug_assert!(basename.parent().is_none());
+ debug_assert!(validate_basename(basename).is_ok());
+
if self.entries.contains_key(basename) {
Err(io::Error::from_raw_os_error(libc::EEXIST))
} else if self.entries.len() >= MAX_ENTRIES.into() {
@@ -115,6 +116,43 @@
}
}
+/// An in-memory directory representation of a directory structure.
+pub struct InMemoryDir(HashMap<PathBuf, Inode>);
+
+impl InMemoryDir {
+ /// Creates an empty instance of `InMemoryDir`.
+ pub fn new() -> Self {
+ // Hash map is empty since "." and ".." are excluded in entries.
+ InMemoryDir(HashMap::new())
+ }
+
+ /// Returns the number of entries in the directory (not including "." and "..").
+ pub fn number_of_entries(&self) -> u16 {
+ self.0.len() as u16 // limited to MAX_ENTRIES
+ }
+
+ /// Adds an entry (name and the inode number) to the directory. Fails if already exists. The
+ /// caller is responsible for ensure the inode uniqueness.
+ pub fn add_entry(&mut self, basename: &Path, inode: Inode) -> io::Result<()> {
+ validate_basename(basename)?;
+ if self.0.len() >= MAX_ENTRIES.into() {
+ return Err(io::Error::from_raw_os_error(libc::EMLINK));
+ }
+
+ if let hash_map::Entry::Vacant(entry) = self.0.entry(basename.to_path_buf()) {
+ entry.insert(inode);
+ Ok(())
+ } else {
+ Err(io::Error::from_raw_os_error(libc::EEXIST))
+ }
+ }
+
+ /// Looks up an entry inode by name. `None` if not found.
+ pub fn lookup_inode(&self, basename: &Path) -> Option<Inode> {
+ self.0.get(basename).copied()
+ }
+}
+
fn into_io_error(e: VirtFdServiceStatus) -> io::Error {
let maybe_errno = e.service_specific_error();
if maybe_errno > 0 {