Remove the shim kernel crate

kernel/src/syscall/readlink.rs

@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::SyscallReturn;
+use crate::{
+    fs::{
+        file_table::FileDesc,
+        fs_resolver::{FsPath, AT_FDCWD},
+    },
+    prelude::*,
+    syscall::constants::MAX_FILENAME_LEN,
+};
+
+pub fn sys_readlinkat(
+    dirfd: FileDesc,
+    path_addr: Vaddr,
+    usr_buf_addr: Vaddr,
+    usr_buf_len: usize,
+    ctx: &Context,
+) -> Result<SyscallReturn> {
+    let user_space = ctx.get_user_space();
+    let path = user_space.read_cstring(path_addr, MAX_FILENAME_LEN)?;
+    debug!(
+        "dirfd = {}, path = {:?}, usr_buf_addr = 0x{:x}, usr_buf_len = 0x{:x}",
+        dirfd, path, usr_buf_addr, usr_buf_len
+    );
+
+    let dentry = {
+        let path = path.to_string_lossy();
+        if path.is_empty() {
+            return_errno_with_message!(Errno::ENOENT, "path is empty");
+        }
+        let fs_path = FsPath::new(dirfd, path.as_ref())?;
+        ctx.process.fs().read().lookup_no_follow(&fs_path)?
+    };
+    let linkpath = dentry.inode().read_link()?;
+    let bytes = linkpath.as_bytes();
+    let write_len = bytes.len().min(usr_buf_len);
+    user_space.write_bytes(usr_buf_addr, &mut VmReader::from(&bytes[..write_len]))?;
+    Ok(SyscallReturn::Return(write_len as _))
+}
+
+pub fn sys_readlink(
+    path_addr: Vaddr,
+    usr_buf_addr: Vaddr,
+    usr_buf_len: usize,
+    ctx: &Context,
+) -> Result<SyscallReturn> {
+    self::sys_readlinkat(AT_FDCWD, path_addr, usr_buf_addr, usr_buf_len, ctx)
+}