Reorganize the codebase

services/libs/jinux-std/src/syscall/readlink.rs

@@ -0,0 +1,48 @@
+use crate::fs::{
+    file_table::FileDescripter,
+    fs_resolver::{FsPath, AT_FDCWD},
+};
+use crate::log_syscall_entry;
+use crate::prelude::*;
+use crate::syscall::constants::MAX_FILENAME_LEN;
+use crate::util::{read_cstring_from_user, write_bytes_to_user};
+
+use super::SyscallReturn;
+use super::SYS_READLINKAT;
+
+pub fn sys_readlinkat(
+    dirfd: FileDescripter,
+    pathname_addr: Vaddr,
+    usr_buf_addr: Vaddr,
+    usr_buf_len: usize,
+) -> Result<SyscallReturn> {
+    log_syscall_entry!(SYS_READLINKAT);
+    let pathname = read_cstring_from_user(pathname_addr, MAX_FILENAME_LEN)?;
+    debug!(
+        "dirfd = {}, pathname = {:?}, usr_buf_addr = 0x{:x}, usr_buf_len = 0x{:x}",
+        dirfd, pathname, usr_buf_addr, usr_buf_len
+    );
+
+    let current = current!();
+    let dentry = {
+        let pathname = pathname.to_string_lossy();
+        if pathname.is_empty() {
+            return_errno_with_message!(Errno::ENOENT, "path is empty");
+        }
+        let fs_path = FsPath::new(dirfd, pathname.as_ref())?;
+        current.fs().read().lookup_no_follow(&fs_path)?
+    };
+    let linkpath = dentry.read_link()?;
+    let bytes = linkpath.as_bytes();
+    let write_len = bytes.len().min(usr_buf_len);
+    write_bytes_to_user(usr_buf_addr, &bytes[..write_len])?;
+    Ok(SyscallReturn::Return(write_len as _))
+}
+
+pub fn sys_readlink(
+    pathname_addr: Vaddr,
+    usr_buf_addr: Vaddr,
+    usr_buf_len: usize,
+) -> Result<SyscallReturn> {
+    self::sys_readlinkat(AT_FDCWD, pathname_addr, usr_buf_addr, usr_buf_len)
+}