Refactor project structure

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

@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::{SyscallReturn, SYS_LINKAT};
+use crate::{
+    fs::{
+        file_table::FileDescripter,
+        fs_resolver::{FsPath, AT_FDCWD},
+    },
+    log_syscall_entry,
+    prelude::*,
+    syscall::constants::MAX_FILENAME_LEN,
+    util::read_cstring_from_user,
+};
+
+pub fn sys_linkat(
+    old_dirfd: FileDescripter,
+    old_pathname_addr: Vaddr,
+    new_dirfd: FileDescripter,
+    new_pathname_addr: Vaddr,
+    flags: u32,
+) -> Result<SyscallReturn> {
+    log_syscall_entry!(SYS_LINKAT);
+    let old_pathname = read_cstring_from_user(old_pathname_addr, MAX_FILENAME_LEN)?;
+    let new_pathname = read_cstring_from_user(new_pathname_addr, MAX_FILENAME_LEN)?;
+    let flags =
+        LinkFlags::from_bits(flags).ok_or(Error::with_message(Errno::EINVAL, "invalid flags"))?;
+    debug!(
+        "old_dirfd = {}, old_pathname = {:?}, new_dirfd = {}, new_pathname = {:?}, flags = {:?}",
+        old_dirfd, old_pathname, new_dirfd, new_pathname, flags
+    );
+
+    let current = current!();
+    let (old_dentry, new_dir_dentry, new_name) = {
+        let old_pathname = old_pathname.to_string_lossy();
+        if old_pathname.ends_with('/') {
+            return_errno_with_message!(Errno::EPERM, "oldpath is dir");
+        }
+        if old_pathname.is_empty() && !flags.contains(LinkFlags::AT_EMPTY_PATH) {
+            return_errno_with_message!(Errno::ENOENT, "oldpath is empty");
+        }
+        let new_pathname = new_pathname.to_string_lossy();
+        if new_pathname.ends_with('/') || new_pathname.is_empty() {
+            return_errno_with_message!(Errno::ENOENT, "newpath is dir or is empty");
+        }
+
+        let old_fs_path = FsPath::new(old_dirfd, old_pathname.as_ref())?;
+        let new_fs_path = FsPath::new(new_dirfd, new_pathname.as_ref())?;
+        let fs = current.fs().read();
+        let old_dentry = if flags.contains(LinkFlags::AT_SYMLINK_FOLLOW) {
+            fs.lookup(&old_fs_path)?
+        } else {
+            fs.lookup_no_follow(&old_fs_path)?
+        };
+        let (new_dir_dentry, new_name) = fs.lookup_dir_and_base_name(&new_fs_path)?;
+        (old_dentry, new_dir_dentry, new_name)
+    };
+    new_dir_dentry.link(&old_dentry, &new_name)?;
+    Ok(SyscallReturn::Return(0))
+}
+
+pub fn sys_link(old_pathname_addr: Vaddr, new_pathname_addr: Vaddr) -> Result<SyscallReturn> {
+    self::sys_linkat(AT_FDCWD, old_pathname_addr, AT_FDCWD, new_pathname_addr, 0)
+}
+
+bitflags::bitflags! {
+    pub struct LinkFlags: u32 {
+        const AT_EMPTY_PATH = 0x1000;
+        const AT_SYMLINK_FOLLOW = 0x400;
+    }
+}