Changed signature for openat function (#2139)

* Changed signature for openat function

Signed-off-by: carlosb1 <[email protected]>

* Fixed tests for openat to apply Options

Signed-off-by: carlosb1 <[email protected]>

* Updated changelog

Signed-off-by: carlosb1 <[email protected]>

* Fixed num PR

Signed-off-by: carlosb1 <[email protected]>

---------

Signed-off-by: carlosb1 <[email protected]>

Author: carlosb1

CHANGELOG.md

@@ -21,6 +21,9 @@ This project adheres to [Semantic Versioning](https://semver.org/).
   - `unistd::getpeereid`
 
   ([#2137](https://github.com/nix-rust/nix/pull/2137))
+  
+- Changed `openat()` and `Dir::openat()`, now take optional `dirfd`s
+  ([#2139](https://github.com/nix-rust/nix/pull/2139))
 
 - `FdSet::{insert, remove, contains}` now take `BorrowedFd` arguments, and have
   relaxed lifetime requirements relative to 0.27.1.

src/dir.rs

@@ -44,7 +44,7 @@ impl Dir {
 
     /// Opens the given path as with `fcntl::openat`.
     pub fn openat<P: ?Sized + NixPath>(
-        dirfd: RawFd,
+        dirfd: Option<RawFd>,
         path: &P,
         oflag: OFlag,
         mode: sys::stat::Mode,

src/fcntl.rs

@@ -220,13 +220,13 @@ pub fn open<P: ?Sized + NixPath>(
 #[allow(clippy::useless_conversion)]
 #[cfg(not(target_os = "redox"))]
 pub fn openat<P: ?Sized + NixPath>(
-    dirfd: RawFd,
+    dirfd: Option<RawFd>,
     path: &P,
     oflag: OFlag,
     mode: Mode,
 ) -> Result<RawFd> {
     let fd = path.with_nix_path(|cstr| unsafe {
-        libc::openat(dirfd, cstr.as_ptr(), oflag.bits(), mode.bits() as c_uint)
+        libc::openat(at_rawfd(dirfd), cstr.as_ptr(), oflag.bits(), mode.bits() as c_uint)
     })?;
     Errno::result(fd)
 }

test/test_fcntl.rs

@@ -42,7 +42,7 @@ fn test_openat() {
         open(tmp.path().parent().unwrap(), OFlag::empty(), Mode::empty())
             .unwrap();
     let fd = openat(
-        dirfd,
+        Some(dirfd),
         tmp.path().file_name().unwrap(),
         OFlag::O_RDONLY,
         Mode::empty(),