Refactor project structure

kernel/aster-nix/src/syscall/pread64.rs

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::{SyscallReturn, SYS_PREAD64};
+use crate::{
+    fs::{file_table::FileDescripter, utils::SeekFrom},
+    log_syscall_entry,
+    prelude::*,
+    util::write_bytes_to_user,
+};
+
+pub fn sys_pread64(
+    fd: FileDescripter,
+    buf_ptr: Vaddr,
+    count: usize,
+    pos: i64,
+) -> Result<SyscallReturn> {
+    log_syscall_entry!(SYS_PREAD64);
+    debug!(
+        "fd = {}, buf = 0x{:x}, count = 0x{:x}, pos = 0x{:x}",
+        fd, buf_ptr, count, pos
+    );
+
+    let current = current!();
+    let file_table = current.file_table().lock();
+    let file = file_table.get_file(fd)?;
+
+    let seek_from = SeekFrom::Start(pos as usize);
+    file.seek(seek_from)?;
+
+    let read_len = {
+        let mut buffer = vec![0u8; count];
+        let read_len = file.read(&mut buffer)?;
+        write_bytes_to_user(buf_ptr, &buffer)?;
+        read_len
+    };
+
+    Ok(SyscallReturn::Return(read_len as _))
+}