Merge pull request #275 from 879650736/axfs

Enhance truncate,add urandom ,update axfs_crates dependencies

Author: equation314

Cargo.lock

@@ -87,8 +87,26 @@ impl VfsNodeOps for FileWrapper<'static> {
 
     fn truncate(&self, size: u64) -> VfsResult {
         let mut file = self.0.lock();
-        file.seek(SeekFrom::Start(size)).map_err(as_vfs_err)?; // TODO: more efficient
-        file.truncate().map_err(as_vfs_err)
+        let current_size = file.seek(SeekFrom::End(0)).map_err(as_vfs_err)?;
+
+        if size <= current_size {
+            // If the target size is smaller than the current size,
+            // perform a standard truncation operation
+            file.seek(SeekFrom::Start(size)).map_err(as_vfs_err)?; // TODO: more efficient
+            file.truncate().map_err(as_vfs_err)
+        } else {
+            // Calculate the number of bytes to fill
+            let mut zeros_needed = size - current_size;
+            // Create a buffer of zeros
+            let zeros = [0u8; 4096];
+            while zeros_needed > 0 {
+                let to_write = core::cmp::min(zeros_needed, zeros.len() as u64);
+                let write_buf = &zeros[..to_write as usize];
+                file.write(write_buf).map_err(as_vfs_err)?;
+                zeros_needed -= to_write;
+            }
+            Ok(())
+        }
     }
 }
 

modules/axfs/src/fs/fatfs.rs

@@ -7,11 +7,13 @@ use crate::fs;
 pub(crate) fn devfs() -> Arc<fs::devfs::DeviceFileSystem> {
     let null = fs::devfs::NullDev;
     let zero = fs::devfs::ZeroDev;
+    let urandom = fs::devfs::UrandomDev::default();
     let bar = fs::devfs::ZeroDev;
     let devfs = fs::devfs::DeviceFileSystem::new();
     let foo_dir = devfs.mkdir("foo");
     devfs.add("null", Arc::new(null));
     devfs.add("zero", Arc::new(zero));
+    devfs.add("urandom", Arc::new(urandom));
     foo_dir.add("bar", Arc::new(bar));
     Arc::new(devfs)
 }