youknowone · Oct 30, 2026 · Oct 29, 2026
diff --git a/crates/host_env/src/posix.rs b/crates/host_env/src/posix.rs
@@ -12,6 +12,7 @@ use std::os::fd::{AsFd, AsRawFd, BorrowedFd, IntoRawFd, OwnedFd};
 use std::path::Path;
 
 pub use super::posix_unix_like::*;
+pub use crate::os::{AccessMode, F_OK, R_OK, W_OK, X_OK};
 
 pub use libc::{c_char, pid_t};
 
@@ -947,23 +948,24 @@ pub fn get_number_of_os_threads() -> isize {
     0
 }
 
+#[cfg(any(target_os = "espidf", target_os = "horizon", target_os = "vita",))]
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub struct Permissions {
     pub is_readable: bool,
     pub is_writable: bool,
     pub is_executable: bool,
 }
 
-pub use crate::os::{AccessMode, F_OK, R_OK, W_OK, X_OK};
-
-fn get_permissions(mode: u32) -> Permissions {
+#[cfg(any(target_os = "espidf", target_os = "horizon", target_os = "vita",))]
+const fn get_permissions(mode: u32) -> Permissions {
     Permissions {
         is_readable: mode & 4 != 0,
         is_writable: mode & 2 != 0,
         is_executable: mode & 1 != 0,
     }
 }
 
+#[cfg(any(target_os = "espidf", target_os = "horizon", target_os = "vita",))]
 pub fn get_right_permission(
     mode: u32,
     file_owner: u32,
@@ -1026,29 +1028,30 @@ pub fn check_access(
     mode: u8,
     effective_ids: bool,
     follow_symlinks: bool,
-) -> Result<bool, AccessError> {
+) -> bool {
     use std::os::unix::fs::MetadataExt;
 
     let Some(mode) = AccessMode::from_bits(mode) else {
-        return Err(AccessError::InvalidMode);
+        return false;
     };
 
-    let metadata = match crate::fs::metadata(path) {
-        Ok(m) => m,
-        Err(_) => return Ok(false),
+    let Ok(metadata) = crate::fs::metadata(path) else {
+        return false;
     };
 
     if mode.is_empty() {
-        return Ok(true);
+        return true;
     }
 
-    let perm = get_right_permission(metadata.mode(), metadata.uid(), metadata.gid())?;
+    let Ok(perm) = get_right_permission(metadata.mode(), metadata.uid(), metadata.gid()) else {
+        return false;
+    };
 
     let r_ok = !mode.contains(&crate::os::AccessFlag::R) || perm.is_readable;
     let w_ok = !mode.contains(&crate::os::AccessFlag::W) || perm.is_writable;
     let x_ok = !mode.contains(&crate::os::AccessFlag::X) || perm.is_executable;
 
-    Ok(r_ok && w_ok && x_ok)
+    r_ok && w_ok && x_ok
 }
 
 pub fn close_fds(above: i32, keep: &[BorrowedFd<'_>]) {

diff --git a/crates/host_env/src/posix_unix_like.rs b/crates/host_env/src/posix_unix_like.rs
@@ -31,9 +31,9 @@ pub fn check_access(
     access: u8,
     #[cfg_attr(target_os = "android", expect(unused))] effective_ids: bool,
     follow_symlinks: bool,
-) -> Result<bool, AccessError> {
+) -> bool {
     let dir_fd = dir_fd.as_ref().map_or(fs::CWD, AsFd::as_fd);
-    let access = Access::from_bits(access as _).ok_or(AccessError::InvalidMode)?;
+    let access = Access::from_bits_retain(access as _);
 
     #[cfg(not(target_os = "android"))]
     let flags = if effective_ids {
@@ -50,7 +50,7 @@ pub fn check_access(
     });
 
     // CPython returns false for all error codes.
-    Ok(fs::accessat(dir_fd, path.as_ref(), access, flags).is_ok())
+    fs::accessat(dir_fd, path.as_ref(), access, flags).is_ok()
 }
 
 /// https://pubs.opengroup.org/onlinepubs/9799919799/functions/mkdir.html

diff --git a/crates/vm/src/exceptions.rs b/crates/vm/src/exceptions.rs
@@ -1652,18 +1652,6 @@ impl ToPyException for rustpython_host_env::fcntl::LockfError {
     }
 }
 
-#[cfg(unix)]
-impl ToPyException for rustpython_host_env::posix::AccessError {
-    fn to_pyexception(&self, vm: &VirtualMachine) -> PyBaseExceptionRef {
-        match self {
-            Self::InvalidMode => vm.new_value_error(
-                "One of the flags is wrong, there are only 4 possibilities F_OK, R_OK, W_OK and X_OK",
-            ),
-            Self::Os(errno) => std::io::Error::from_raw_os_error(*errno).to_pyexception(vm),
-        }
-    }
-}
-
 #[cfg(all(unix, not(target_os = "redox")))]
 impl ToPyException for rustpython_host_env::socket::AncillaryPackError {
     fn to_pyexception(&self, vm: &VirtualMachine) -> PyBaseExceptionRef {

diff --git a/crates/vm/src/stdlib/posix.rs b/crates/vm/src/stdlib/posix.rs
@@ -19,7 +19,7 @@ pub mod module {
     use crate::{
         AsObject, Py, PyObject, PyObjectRef, PyResult, VirtualMachine,
         builtins::{PyBytesRef, PyDictRef, PyInt, PyListRef, PyTuple, PyTupleRef, PyUtf8Str},
-        convert::{IntoPyException, ToPyException, ToPyObject, TryFromObject},
+        convert::{IntoPyException, ToPyObject, TryFromObject},
         exceptions::OSErrorBuilder,
         function::{ArgBytesLike, ArgMapping, Either, OptionalArg, PySsize},
         ospath::{OsPath, OsPathOrFd},
@@ -398,8 +398,12 @@ pub mod module {
             .collect())
     }
 
+    #[allow(clippy::unnecessary_wraps)]
     #[pyfunction]
-    pub(super) fn access(args: AccessArgs<'_>, vm: &VirtualMachine) -> PyResult<bool> {
+    pub(super) fn access(
+        args: AccessArgs<'_>,
+        #[allow(unused_variables)] vm: &VirtualMachine,
+    ) -> PyResult<bool> {
         #[cfg(any(
             target_os = "android",
             target_os = "espidf",
@@ -439,14 +443,13 @@ pub mod module {
         )))]
         let dir_fd = None;
 
-        rustpython_host_env::posix::check_access(
+        Ok(rustpython_host_env::posix::check_access(
             dir_fd,
             args.path.as_ref(),
             args.mode,
             args.effective_ids,
             args.follow_symlinks.0,
-        )
-        .map_err(|err| err.to_pyexception(vm))
+        ))
     }
 
     #[pyfunction]

diff --git a/extra_tests/snippets/stdlib_os.py b/extra_tests/snippets/stdlib_os.py
@@ -2,6 +2,7 @@
 import os
 import stat
 import sys
+import tempfile
 import time
 
 from testutils import assert_raises
@@ -640,6 +641,11 @@ def __exit__(self, exc_type, exc_val, exc_tb):
 assert os.access("README.md", os.F_OK) is True
 assert os.access("README.md", os.R_OK) is True
 
+# os.access - CPython returns False for invalid modes for Unix
+if os.name != "nt":
+    with tempfile.NamedTemporaryFile() as tmp:
+        assert not os.access(tmp.name, 255)
+
 # argv and the group list are sequences; an arbitrary iterable must be rejected
 # rather than drained.
 if hasattr(os, "posix_spawn"):