Remove the shim kernel crate

kernel/src/syscall/lseek.rs

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::SyscallReturn;
+use crate::{
+    fs::{file_table::FileDesc, utils::SeekFrom},
+    prelude::*,
+};
+
+pub fn sys_lseek(fd: FileDesc, offset: isize, whence: u32, ctx: &Context) -> Result<SyscallReturn> {
+    debug!("fd = {}, offset = {}, whence = {}", fd, offset, whence);
+    let seek_from = match whence {
+        0 => {
+            if offset < 0 {
+                return_errno!(Errno::EINVAL);
+            }
+            SeekFrom::Start(offset as usize)
+        }
+        1 => SeekFrom::Current(offset),
+        2 => SeekFrom::End(offset),
+        _ => return_errno!(Errno::EINVAL),
+    };
+    let file_table = ctx.process.file_table().lock();
+    let file = file_table.get_file(fd)?;
+    let offset = file.seek(seek_from)?;
+    Ok(SyscallReturn::Return(offset as _))
+}