RustPython · joshuamegnauth54 · Jun 17, 2026
diff --git a/crates/host_env/Cargo.toml b/crates/host_env/Cargo.toml
@@ -20,6 +20,8 @@ paste = { workspace = true }
 
 [target.'cfg(unix)'.dependencies]
 nix = { workspace = true }
+
+[target.'cfg(any(unix, target_os = "macos", target_os = "redox", target_os = "wasi"))'.dependencies]
 rustix = { workspace = true }
 
 [target.'cfg(any(not(target_arch = "wasm32"), target_os = "wasi"))'.dependencies]

diff --git a/crates/host_env/src/crt_fd.rs b/crates/host_env/src/crt_fd.rs
@@ -5,7 +5,7 @@ use alloc::fmt;
 use core::cmp;
 use std::{ffi, io};
 
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 use std::os::fd::AsFd;
 #[cfg(not(windows))]
 use std::os::fd::{AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd};
@@ -209,42 +209,42 @@ impl Owned {
     }
 }
 
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 impl From<Owned> for OwnedFd {
     fn from(fd: Owned) -> Self {
         fd.inner
     }
 }
 
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 impl From<OwnedFd> for Owned {
     fn from(fd: OwnedFd) -> Self {
         Self { inner: fd }
     }
 }
 
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 impl AsFd for Owned {
     fn as_fd(&self) -> BorrowedFd<'_> {
         self.inner.as_fd()
     }
 }
 
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 impl AsRawFd for Owned {
     fn as_raw_fd(&self) -> RawFd {
         self.as_raw()
     }
 }
 
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 impl FromRawFd for Owned {
     unsafe fn from_raw_fd(fd: RawFd) -> Self {
         unsafe { Self::from_raw(fd) }
     }
 }
 
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 impl IntoRawFd for Owned {
     fn into_raw_fd(self) -> RawFd {
         self.into_raw()
@@ -287,28 +287,28 @@ impl Borrowed<'_> {
     }
 }
 
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 impl<'fd> From<Borrowed<'fd>> for BorrowedFd<'fd> {
     fn from(fd: Borrowed<'fd>) -> Self {
         fd.inner
     }
 }
 
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 impl<'fd> From<BorrowedFd<'fd>> for Borrowed<'fd> {
     fn from(fd: BorrowedFd<'fd>) -> Self {
         Self { inner: fd }
     }
 }
 
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 impl AsFd for Borrowed<'_> {
     fn as_fd(&self) -> BorrowedFd<'_> {
         self.inner.as_fd()
     }
 }
 
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 impl AsRawFd for Borrowed<'_> {
     fn as_raw_fd(&self) -> RawFd {
         self.as_raw()

diff --git a/crates/host_env/src/lib.rs b/crates/host_env/src/lib.rs
@@ -52,6 +52,9 @@ pub mod posix;
 #[cfg(target_os = "wasi")]
 #[path = "posix_wasi.rs"]
 pub mod posix;
+#[cfg(windows)]
+#[path = "posix_windows.rs"]
+pub mod posix;
 #[cfg(unix)]
 pub mod pwd;
 #[cfg(unix)]

diff --git a/crates/host_env/src/posix.rs b/crates/host_env/src/posix.rs
@@ -10,6 +10,8 @@ use std::os::fd::FromRawFd;
 use std::os::fd::{AsFd, AsRawFd, BorrowedFd, IntoRawFd, OwnedFd};
 use std::path::Path;
 
+use crate::crt_fd;
+
 pub struct UnameInfo {
     pub sysname: String,
     pub nodename: String,
@@ -174,24 +176,14 @@ pub fn fcopyfile(in_fd: i32, out_fd: i32, flags: u32) -> std::io::Result<()> {
     }
 }
 
-#[cfg(not(windows))]
-pub fn make_dir(path: &CStr, mode: u32) -> std::io::Result<()> {
-    let ret = unsafe { libc::mkdir(path.as_ptr(), mode as _) };
-    if ret < 0 {
-        Err(std::io::Error::last_os_error())
-    } else {
-        Ok(())
-    }
-}
-
-#[cfg(all(not(windows), not(target_os = "redox")))]
-pub fn make_dir_at(dir_fd: i32, path: &CStr, mode: u32) -> std::io::Result<()> {
-    let ret = unsafe { libc::mkdirat(dir_fd, path.as_ptr(), mode as _) };
-    if ret < 0 {
-        Err(std::io::Error::last_os_error())
-    } else {
-        Ok(())
-    }
+#[cfg(any(unix, target_os = "wasi"))]
+pub fn make_dir(
+    dir_fd: Option<crt_fd::Borrowed<'_>>,
+    path: &impl AsRef<Path>,
+    mode: libc::mode_t,
+) -> std::io::Result<()> {
+    let dir_fd = dir_fd.as_ref().map_or(rustix::fs::CWD, AsFd::as_fd);
+    rustix::fs::mkdirat(dir_fd, path.as_ref(), mode.into()).map_err(Into::into)
 }
 
 #[cfg(unix)]

diff --git a/crates/host_env/src/posix_wasi.rs b/crates/host_env/src/posix_wasi.rs
@@ -1,17 +1,17 @@
 use alloc::ffi::CString;
 use core::{ffi::CStr, time::Duration};
-use std::{ffi::OsStr, io};
+use rustix::fd::AsFd;
+use std::{ffi::OsStr, io, path::Path};
 
-use crate::os::CheckLibcResult;
+use crate::{crt_fd, os::CheckLibcResult};
 
-pub fn make_dir(path: &CStr, mode: u32) -> io::Result<()> {
-    unsafe { libc::mkdir(path.as_ptr(), mode as _) }.check_libc_neg()?;
-    Ok(())
-}
-
-pub fn make_dir_at(dir_fd: i32, path: &CStr, mode: u32) -> io::Result<()> {
-    unsafe { libc::mkdirat(dir_fd, path.as_ptr(), mode as _) }.check_libc_neg()?;
-    Ok(())
+pub fn make_dir(
+    dir_fd: Option<crt_fd::Borrowed<'_>>,
+    path: &impl AsRef<Path>,
+    mode: libc::mode_t,
+) -> std::io::Result<()> {
+    let dir_fd = dir_fd.as_ref().map_or(rustix::fs::CWD, AsFd::as_fd);
+    rustix::fs::mkdirat(dir_fd, path.as_ref(), mode.into()).map_err(Into::into)
 }
 
 pub fn remove_dir_at(dir_fd: i32, path: &CStr) -> io::Result<()> {

diff --git a/crates/host_env/src/posix_windows.rs b/crates/host_env/src/posix_windows.rs
@@ -0,0 +1,22 @@
+//! POSIX-compatible API for Windows.
+//!
+//! Python wraps POSIX syscalls such as `mkdir` and `open`. Windows doesn't directly implement
+//! these syscalls, but they can be emulated with a mix of the Windows API and the Rust standard
+//! library, the latter of which calls the former.
+
+use std::{fs, io, path::Path};
+
+use crate::crt_fd;
+
+#[expect(non_camel_case_types)]
+pub type mode_t = u32;
+
+pub fn make_dir(
+    dir_fd: Option<crt_fd::Borrowed<'_>>,
+    path: &impl AsRef<Path>,
+    _mode: mode_t,
+) -> io::Result<()> {
+    debug_assert!(dir_fd.is_none());
+    // TODO: On Windows, Python has an override if the mode is 0o700
+    fs::create_dir(path)
+}
diff --git a/crates/vm/src/stdlib/os.rs b/crates/vm/src/stdlib/os.rs
@@ -10,6 +10,12 @@ use crate::{
 };
 use std::{io, path::Path};
 
+#[cfg(not(windows))]
+use libc::mode_t;
+
+#[cfg(windows)]
+use crate::host_env::posix::mode_t;
+
 pub(crate) fn fs_metadata<P: AsRef<Path>>(
     path: P,
     follow_symlink: bool,
@@ -29,7 +35,7 @@ pub struct TargetIsDirectory {
 }
 
 cfg_select! {
-    all(any(unix, target_os = "wasi"), not(target_os = "redox")) => {
+    any(unix, target_os = "wasi") => {
         use libc::AT_FDCWD;
     }
     _ => {
@@ -154,7 +160,7 @@ impl ToPyObject for crt_fd::Borrowed<'_> {
 
 #[pymodule(sub)]
 pub(super) mod _os {
-    use super::{DirFd, FollowSymlinks, SupportFunc};
+    use super::{DirFd, FollowSymlinks, SupportFunc, mode_t};
     use crate::host_env::fileutils::StatStruct;
     #[cfg(any(unix, windows))]
     use crate::utils::ToCString;
@@ -184,7 +190,7 @@ pub(super) mod _os {
     use std::{fs, io, path::PathBuf, time::SystemTime};
 
     const OPEN_DIR_FD: bool = cfg!(not(any(windows, target_os = "redox")));
-    pub(crate) const MKDIR_DIR_FD: bool = cfg!(not(any(windows, target_os = "redox")));
+    pub(crate) const MKDIR_DIR_FD: bool = cfg!(any(unix, target_os = "wasi"));
     const STAT_DIR_FD: bool = cfg!(not(any(windows, target_os = "redox")));
     const UTIME_DIR_FD: bool = cfg!(not(any(windows, target_os = "redox")));
     pub(crate) const SYMLINK_DIR_FD: bool = cfg!(not(any(windows, target_os = "redox")));
@@ -338,32 +344,24 @@ pub(super) mod _os {
         }
     }
 
-    #[cfg(not(windows))]
     #[pyfunction]
     fn mkdir(
         path: OsPath,
-        mode: OptionalArg<i32>,
-        dir_fd: DirFd<'_, { MKDIR_DIR_FD as usize }>,
+        mode: OptionalArg<mode_t>,
+        #[cfg_attr(not(any(unix, target_os = "wasi")), expect(unused_variables))] dir_fd: DirFd<
+            '_,
+            { MKDIR_DIR_FD as usize },
+        >,
         vm: &VirtualMachine,
     ) -> PyResult<()> {
         let mode = mode.unwrap_or(0o777);
-        let c_path = path.clone().into_cstring(vm)?;
-        #[cfg(not(target_os = "redox"))]
-        if let Some(fd) = dir_fd.raw_opt() {
-            return if let Err(err) =
-                crate::host_env::posix::make_dir_at(fd, c_path.as_c_str(), mode as u32)
-            {
-                Err(OSErrorBuilder::with_filename(&err, path, vm))
-            } else {
-                Ok(())
-            };
-        }
-        #[cfg(target_os = "redox")]
-        let [] = dir_fd.0;
-        if let Err(err) = crate::host_env::posix::make_dir(c_path.as_c_str(), mode as u32) {
-            return Err(OSErrorBuilder::with_filename(&err, path, vm));
-        }
-        Ok(())
+        #[cfg(any(unix, target_os = "wasi"))]
+        let dir_fd = dir_fd.get_opt();
+        #[cfg(not(any(unix, target_os = "wasi")))]
+        let dir_fd = None;
+
+        crate::host_env::posix::make_dir(dir_fd, &path.path, mode)
+            .map_err(|err| OSErrorBuilder::with_filename(&err, path, vm))
     }
 
     #[pyfunction]