feat: AT_EMPTY_PATH for linkat() (#2284)

* feat: AT_EMPTY_PATH for linkat()

* try fixing import

* fix changelog name

Author: SteveLauC

changelog/2284.added.md

@@ -0,0 +1 @@
+Enable the `AT_EMPTY_PATH` flag for the `linkat()` function

changelog/2284.removed.md

@@ -0,0 +1 @@
+The `LinkatFlags` type has been deprecated, please use `AtFlags` instead.

src/unistd.rs

@@ -1253,19 +1253,24 @@ pub fn isatty(fd: RawFd) -> Result<bool> {
     }
 }
 
-/// Flags for `linkat` function.
-#[derive(Clone, Copy, Debug)]
-pub enum LinkatFlags {
-    SymlinkFollow,
-    NoSymlinkFollow,
+#[cfg(not(target_os = "redox"))]
+pub type LinkatFlags = AtFlags;
+#[cfg(not(target_os = "redox"))]
+impl LinkatFlags {
+    #[deprecated(since = "0.28.0", note = "The variant is deprecated, please use `AtFlags` instead")]
+    #[allow(non_upper_case_globals)]
+    pub const SymlinkFollow: LinkatFlags = LinkatFlags::AT_SYMLINK_FOLLOW;
+    #[deprecated(since = "0.28.0", note = "The variant is deprecated, please use `AtFlags` instead")]
+    #[allow(non_upper_case_globals)]
+    pub const NoSymlinkFollow: LinkatFlags = LinkatFlags::empty();
 }
 
 /// Link one file to another file
 ///
 /// Creates a new link (directory entry) at `newpath` for the existing file at `oldpath`. In the
 /// case of a relative `oldpath`, the path is interpreted relative to the directory associated
 /// with file descriptor `olddirfd` instead of the current working directory and similiarly for
-/// `newpath` and file descriptor `newdirfd`. In case `flag` is LinkatFlags::SymlinkFollow and
+/// `newpath` and file descriptor `newdirfd`. In case `flag` is `AtFlags::AT_SYMLINK_FOLLOW` and
 /// `oldpath` names a symoblic link, a new link for the target of the symbolic link is created.
 /// If either `olddirfd` or `newdirfd` is `None`, `AT_FDCWD` is used respectively where `oldpath`
 /// and/or `newpath` is then interpreted relative to the current working directory of the calling
@@ -1279,21 +1284,16 @@ pub fn linkat<P: ?Sized + NixPath>(
     oldpath: &P,
     newdirfd: Option<RawFd>,
     newpath: &P,
-    flag: LinkatFlags,
+    flag: AtFlags,
 ) -> Result<()> {
-    let atflag = match flag {
-        LinkatFlags::SymlinkFollow => AtFlags::AT_SYMLINK_FOLLOW,
-        LinkatFlags::NoSymlinkFollow => AtFlags::empty(),
-    };
-
     let res = oldpath.with_nix_path(|oldcstr| {
         newpath.with_nix_path(|newcstr| unsafe {
             libc::linkat(
                 at_rawfd(olddirfd),
                 oldcstr.as_ptr(),
                 at_rawfd(newdirfd),
                 newcstr.as_ptr(),
-                atflag.bits() as libc::c_int,
+                flag.bits(),
             )
         })
     })??;

test/test_unistd.rs

@@ -897,6 +897,8 @@ fn test_symlinkat() {
 #[test]
 #[cfg(not(any(target_os = "redox", target_os = "haiku")))]
 fn test_linkat_file() {
+    use nix::fcntl::AtFlags;
+
     let tempdir = tempdir().unwrap();
     let oldfilename = "foo.txt";
     let oldfilepath = tempdir.path().join(oldfilename);
@@ -918,7 +920,7 @@ fn test_linkat_file() {
         oldfilename,
         Some(dirfd),
         newfilename,
-        LinkatFlags::SymlinkFollow,
+        AtFlags::AT_SYMLINK_FOLLOW,
     )
     .unwrap();
     assert!(newfilepath.exists());
@@ -927,6 +929,8 @@ fn test_linkat_file() {
 #[test]
 #[cfg(not(any(target_os = "redox", target_os = "haiku")))]
 fn test_linkat_olddirfd_none() {
+    use nix::fcntl::AtFlags;
+
     let _dr = crate::DirRestore::new();
 
     let tempdir_oldfile = tempdir().unwrap();
@@ -955,7 +959,7 @@ fn test_linkat_olddirfd_none() {
         oldfilename,
         Some(dirfd),
         newfilename,
-        LinkatFlags::SymlinkFollow,
+        AtFlags::AT_SYMLINK_FOLLOW,
     )
     .unwrap();
     assert!(newfilepath.exists());
@@ -964,6 +968,8 @@ fn test_linkat_olddirfd_none() {
 #[test]
 #[cfg(not(any(target_os = "redox", target_os = "haiku")))]
 fn test_linkat_newdirfd_none() {
+    use nix::fcntl::AtFlags;
+
     let _dr = crate::DirRestore::new();
 
     let tempdir_oldfile = tempdir().unwrap();
@@ -992,7 +998,7 @@ fn test_linkat_newdirfd_none() {
         oldfilename,
         None,
         newfilename,
-        LinkatFlags::SymlinkFollow,
+        AtFlags::AT_SYMLINK_FOLLOW,
     )
     .unwrap();
     assert!(newfilepath.exists());
@@ -1001,6 +1007,8 @@ fn test_linkat_newdirfd_none() {
 #[test]
 #[cfg(not(any(apple_targets, target_os = "redox", target_os = "haiku")))]
 fn test_linkat_no_follow_symlink() {
+    use nix::fcntl::AtFlags;
+
     let _m = crate::CWD_LOCK.read();
 
     let tempdir = tempdir().unwrap();
@@ -1030,7 +1038,7 @@ fn test_linkat_no_follow_symlink() {
         symoldfilename,
         Some(dirfd),
         newfilename,
-        LinkatFlags::NoSymlinkFollow,
+        AtFlags::empty(),
     )
     .unwrap();
 
@@ -1044,6 +1052,8 @@ fn test_linkat_no_follow_symlink() {
 #[test]
 #[cfg(not(any(target_os = "redox", target_os = "haiku")))]
 fn test_linkat_follow_symlink() {
+    use nix::fcntl::AtFlags;
+
     let _m = crate::CWD_LOCK.read();
 
     let tempdir = tempdir().unwrap();
@@ -1073,7 +1083,7 @@ fn test_linkat_follow_symlink() {
         symoldfilename,
         Some(dirfd),
         newfilename,
-        LinkatFlags::SymlinkFollow,
+        AtFlags::AT_SYMLINK_FOLLOW,
     )
     .unwrap();