Read Merkle tree once per file
EagerChunkReader is added to read the wrapper Merkle tree reader. Also
add a function to calculate the tree size, in order to know how much
bytes to read.
Separately, add a check in fd_server to prevent crash when the read size
is 0.
Bug: 182827266
Test: atest AuthFsHostTest authfs_device_test_src_lib
Change-Id: Ibff8c9ac091f1449aec8f4a52cd148e6f41d7b33
diff --git a/authfs/src/file.rs b/authfs/src/file.rs
index 9bbf3ef..44e60d8 100644
--- a/authfs/src/file.rs
+++ b/authfs/src/file.rs
@@ -8,10 +8,11 @@
use binder::unstable_api::{new_spibinder, AIBinder};
use binder::FromIBinder;
+use std::convert::TryFrom;
use std::io;
use std::path::{Path, MAIN_SEPARATOR};
-use crate::common::CHUNK_SIZE;
+use crate::common::{divide_roundup, CHUNK_SIZE};
use authfs_aidl_interface::aidl::com::android::virt::fs::IVirtFdService::IVirtFdService;
use authfs_aidl_interface::binder::{Status, Strong};
@@ -83,3 +84,39 @@
Err(io::Error::from_raw_os_error(libc::EINVAL))
}
}
+
+pub struct EagerChunkReader {
+ buffer: Vec<u8>,
+}
+
+impl EagerChunkReader {
+ pub fn new<F: ReadByChunk>(chunked_file: F, file_size: u64) -> io::Result<EagerChunkReader> {
+ let last_index = divide_roundup(file_size, CHUNK_SIZE);
+ let file_size = usize::try_from(file_size).unwrap();
+ let mut buffer = Vec::with_capacity(file_size);
+ let mut chunk_buffer = [0; CHUNK_SIZE as usize];
+ for index in 0..last_index {
+ let size = chunked_file.read_chunk(index, &mut chunk_buffer)?;
+ buffer.extend_from_slice(&chunk_buffer[..size]);
+ }
+ if buffer.len() < file_size {
+ Err(io::Error::new(
+ io::ErrorKind::InvalidData,
+ format!("Insufficient data size ({} < {})", buffer.len(), file_size),
+ ))
+ } else {
+ Ok(EagerChunkReader { buffer })
+ }
+ }
+}
+
+impl ReadByChunk for EagerChunkReader {
+ fn read_chunk(&self, chunk_index: u64, buf: &mut ChunkBuffer) -> io::Result<usize> {
+ if let Some(chunk) = &self.buffer.chunks(CHUNK_SIZE as usize).nth(chunk_index as usize) {
+ buf[..chunk.len()].copy_from_slice(chunk);
+ Ok(chunk.len())
+ } else {
+ Ok(0) // Read beyond EOF is normal
+ }
+ }
+}