RustPython · Copilot · Apr 11, 2026 · Apr 11, 2026 · Apr 13, 2026 · Apr 14, 2026
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -145,6 +145,7 @@ rustpython-compiler-core = { path = "crates/compiler-core", version = "0.5.0" }
 rustpython-compiler = { path = "crates/compiler", version = "0.5.0" }
 rustpython-codegen = { path = "crates/codegen", version = "0.5.0" }
 rustpython-common = { path = "crates/common", version = "0.5.0" }
+rustpython-host-env = { path = "crates/host_env", version = "0.5.0" }
 rustpython-derive = { path = "crates/derive", version = "0.5.0" }
 rustpython-derive-impl = { path = "crates/derive-impl", version = "0.5.0" }
 rustpython-jit = { path = "crates/jit", version = "0.5.0" }

diff --git a/crates/common/Cargo.toml b/crates/common/Cargo.toml
@@ -36,19 +36,5 @@ lock_api = "0.4"
 siphasher = "1"
 num-complex.workspace = true
 
-[target.'cfg(unix)'.dependencies]
-nix = { workspace = true }
-
-[target.'cfg(windows)'.dependencies]
-widestring = { workspace = true }
-windows-sys = { workspace = true, features = [
-    "Win32_Foundation",
-    "Win32_Networking_WinSock",
-    "Win32_Storage_FileSystem",
-    "Win32_System_Ioctl",
-    "Win32_System_LibraryLoader",
-    "Win32_System_SystemServices",
-] }
-
 [lints]
 workspace = true
diff --git a/crates/common/clippy.toml b/crates/common/clippy.toml
@@ -0,0 +1,32 @@
+disallowed-methods = [
+    { path = "std::fs::read", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::write", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::read_to_string", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::read_dir", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::create_dir", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::create_dir_all", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::remove_file", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::remove_dir", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::metadata", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::symlink_metadata", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::canonicalize", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::File::open", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::File::create", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::fs::OpenOptions::open", reason = "use rustpython_host_env for host filesystem access" },
+    { path = "std::env::var", reason = "use rustpython_host_env for host environment access" },
+    { path = "std::env::var_os", reason = "use rustpython_host_env for host environment access" },
+    { path = "std::env::set_var", reason = "use rustpython_host_env for host environment access" },
+    { path = "std::env::remove_var", reason = "use rustpython_host_env for host environment access" },
+    { path = "std::env::vars", reason = "use rustpython_host_env for host environment access" },
+    { path = "std::env::vars_os", reason = "use rustpython_host_env for host environment access" },
+    { path = "std::env::current_dir", reason = "use rustpython_host_env for host environment access" },
+    { path = "std::env::set_current_dir", reason = "use rustpython_host_env for host environment access" },
+    { path = "std::env::temp_dir", reason = "use rustpython_host_env for host environment access" },
+    { path = "std::process::Command::new", reason = "use rustpython_host_env for host process access" },
+    { path = "std::process::exit", reason = "use rustpython_host_env for host process access" },
+    { path = "std::process::abort", reason = "use rustpython_host_env for host process access" },
+    { path = "std::process::id", reason = "use rustpython_host_env for host process access" },
+    { path = "std::net::TcpStream::connect", reason = "use rustpython_host_env for host network access" },
+    { path = "std::net::TcpListener::bind", reason = "use rustpython_host_env for host network access" },
+    { path = "std::net::UdpSocket::bind", reason = "use rustpython_host_env for host network access" },
+]
diff --git a/crates/common/src/lib.rs b/crates/common/src/lib.rs
@@ -1,37 +1,26 @@
 //! A crate to hold types and functions common to all rustpython components.
 
 #![cfg_attr(not(feature = "std"), no_std)]
+#![deny(clippy::disallowed_methods)]
 
 extern crate alloc;
 
-#[macro_use]
-mod macros;
-pub use macros::*;
-
 pub mod atomic;
 pub mod borrow;
 pub mod boxvec;
 pub mod cformat;
-#[cfg(all(feature = "std", any(unix, windows, target_os = "wasi")))]
-pub mod crt_fd;
 pub mod encodings;
-#[cfg(all(feature = "std", any(not(target_arch = "wasm32"), target_os = "wasi")))]
-pub mod fileutils;
 pub mod float_ops;
 pub mod format;
 pub mod hash;
 pub mod int;
 pub mod linked_list;
 pub mod lock;
-#[cfg(feature = "std")]
-pub mod os;
 pub mod rand;
 pub mod rc;
 pub mod refcount;
 pub mod static_cell;
 pub mod str;
-#[cfg(all(feature = "std", windows))]
-pub mod windows;
 
 pub use rustpython_wtf8 as wtf8;
 

diff --git a/crates/common/src/refcount.rs b/crates/common/src/refcount.rs
@@ -16,8 +16,13 @@ const WEAK_COUNT: usize = 1 << STRONG_WIDTH;
 #[inline(never)]
 #[cold]
 fn refcount_overflow() -> ! {
-    #[cfg(feature = "std")]
-    std::process::abort();
+    #[cfg(all(feature = "std", not(target_arch = "wasm32")))]
+    // SAFETY: abort terminates the process immediately and does not return.
+    unsafe {
+        libc::abort()
+    };
+    #[cfg(all(feature = "std", target_arch = "wasm32"))]
+    core::panic!("refcount overflow");
     #[cfg(not(feature = "std"))]
     core::panic!("refcount overflow");
 }

diff --git a/crates/host_env/Cargo.toml b/crates/host_env/Cargo.toml
@@ -0,0 +1,41 @@
+[package]
+name = "rustpython-host-env"
+description = "Host OS API abstractions for RustPython"
+version.workspace = true
+authors.workspace = true
+edition.workspace = true
+rust-version.workspace = true
+repository.workspace = true
+license.workspace = true
+
+[dependencies]
+rustpython-wtf8 = { workspace = true }
+
+libc = { workspace = true }
+num-traits = { workspace = true }
+
+[target.'cfg(unix)'.dependencies]
+nix = { workspace = true }
+
+[target.'cfg(all(unix, not(target_os = "ios"), not(target_os = "redox")))'.dependencies]
+termios = "0.3.3"
+
+[target.'cfg(windows)'.dependencies]
+widestring = { workspace = true }
+windows-sys = { workspace = true, features = [
+    "Win32_Foundation",
+    "Win32_Globalization",
+    "Win32_Networking_WinSock",
+    "Win32_Storage_FileSystem",
+    "Win32_System_Console",
+    "Win32_System_Diagnostics_Debug",
+    "Win32_System_Ioctl",
+    "Win32_System_LibraryLoader",
+    "Win32_System_SystemInformation",
+    "Win32_System_SystemServices",
+    "Win32_System_Threading",
+    "Win32_System_Time",
+] }
+
+[lints]
+workspace = true
diff --git a/crates/host_env/clippy.toml b/crates/host_env/clippy.toml
@@ -0,0 +1 @@
+disallowed-methods = []
diff --git a/crates/common/src/crt_fd.rs → crates/host_env/src/crt_fd.rs b/crates/common/src/crt_fd.rs → crates/host_env/src/crt_fd.rs
diff --git a/crates/host_env/src/fcntl.rs b/crates/host_env/src/fcntl.rs
@@ -0,0 +1,75 @@
+use std::io;
+
+pub fn fcntl_int(fd: i32, cmd: i32, arg: i32) -> io::Result<i32> {
+    let ret = unsafe { libc::fcntl(fd, cmd, arg) };
+    if ret < 0 {
+        Err(io::Error::last_os_error())
+    } else {
+        Ok(ret)
+    }
+}
+
+pub fn fcntl_with_bytes(fd: i32, cmd: i32, arg: &mut [u8]) -> io::Result<i32> {
+    let ret = unsafe { libc::fcntl(fd, cmd, arg.as_mut_ptr()) };
+    if ret < 0 {
+        Err(io::Error::last_os_error())
+    } else {
+        Ok(ret)
+    }
+}
+
+/// # Safety
+///
+/// `arg` must be a valid pointer for the `request` passed to `ioctl` and must
+/// satisfy the platform ABI requirements for that request.
+pub unsafe fn ioctl_ptr(
+    fd: i32,
+    request: libc::c_ulong,
+    arg: *mut libc::c_void,
+) -> io::Result<i32> {
+    let ret = unsafe { libc::ioctl(fd, request as _, arg) };
+    if ret < 0 {
+        Err(io::Error::last_os_error())
+    } else {
+        Ok(ret)
+    }
+}
+
+pub fn ioctl_int(fd: i32, request: libc::c_ulong, arg: i32) -> io::Result<i32> {
+    let ret = unsafe { libc::ioctl(fd, request as _, arg) };
+    if ret < 0 {
+        Err(io::Error::last_os_error())
+    } else {
+        Ok(ret)
+    }
+}
+
+#[cfg(not(any(target_os = "wasi", target_os = "redox")))]
+pub fn flock(fd: i32, operation: i32) -> io::Result<i32> {
+    let ret = unsafe { libc::flock(fd, operation) };
+    if ret < 0 {
+        Err(io::Error::last_os_error())
+    } else {
+        Ok(ret)
+    }
+}
+
+#[cfg(not(any(target_os = "wasi", target_os = "redox")))]
+pub fn lockf(fd: i32, cmd: i32, lock: &libc::flock) -> io::Result<i32> {
+    let ret = unsafe {
+        libc::fcntl(
+            fd,
+            if (cmd & libc::LOCK_NB) != 0 {
+                libc::F_SETLK
+            } else {
+                libc::F_SETLKW
+            },
+            lock,
+        )
+    };
+    if ret < 0 {
+        Err(io::Error::last_os_error())
+    } else {
+        Ok(ret)
+    }
+}
diff --git a/crates/common/src/fileutils.rs → crates/host_env/src/fileutils.rs b/crates/common/src/fileutils.rs → crates/host_env/src/fileutils.rs
diff --git a/crates/host_env/src/fs.rs b/crates/host_env/src/fs.rs
@@ -0,0 +1,45 @@
+use std::{
+    fs::{self, File, Metadata, ReadDir},
+    io,
+    path::Path,
+};
+
+pub fn open(path: impl AsRef<Path>) -> io::Result<File> {
+    File::open(path)
+}
+
+pub fn read(path: impl AsRef<Path>) -> io::Result<Vec<u8>> {
+    fs::read(path)
+}
+
+pub fn read_to_string(path: impl AsRef<Path>) -> io::Result<String> {
+    fs::read_to_string(path)
+}
+
+pub fn read_dir(path: impl AsRef<Path>) -> io::Result<ReadDir> {
+    fs::read_dir(path)
+}
+
+pub fn create_dir_all(path: impl AsRef<Path>) -> io::Result<()> {
+    fs::create_dir_all(path)
+}
+
+pub fn remove_dir(path: impl AsRef<Path>) -> io::Result<()> {
+    fs::remove_dir(path)
+}
+
+pub fn remove_file(path: impl AsRef<Path>) -> io::Result<()> {
+    fs::remove_file(path)
+}
+
+pub fn metadata(path: impl AsRef<Path>) -> io::Result<Metadata> {
+    fs::metadata(path)
+}
+
+pub fn symlink_metadata(path: impl AsRef<Path>) -> io::Result<Metadata> {
+    fs::symlink_metadata(path)
+}
+
+pub fn open_write(path: impl AsRef<Path>) -> io::Result<File> {
+    fs::OpenOptions::new().write(true).open(path)
+}
diff --git a/crates/host_env/src/lib.rs b/crates/host_env/src/lib.rs
@@ -0,0 +1,42 @@
+extern crate alloc;
+
+#[macro_use]
+mod macros;
+pub use macros::*;
+
+pub mod os;
+
+#[cfg(any(unix, windows, target_os = "wasi"))]
+pub mod crt_fd;
+
+#[cfg(any(not(target_arch = "wasm32"), target_os = "wasi"))]
+pub mod fileutils;
+#[cfg(any(not(target_arch = "wasm32"), target_os = "wasi"))]
+pub mod fs;
+
+#[cfg(windows)]
+pub mod windows;
+
+#[cfg(any(unix, target_os = "wasi"))]
+pub mod fcntl;
+#[cfg(any(unix, windows, target_os = "wasi"))]
+pub mod select;
+#[cfg(unix)]
+pub mod syslog;
+#[cfg(all(unix, not(target_os = "redox"), not(target_os = "ios")))]
+pub mod termios;
+
+#[cfg(unix)]
+pub mod posix;
+#[cfg(all(unix, not(target_os = "redox"), not(target_os = "android")))]
+pub mod shm;
+#[cfg(unix)]
+pub mod signal;
+pub mod time;
+
+#[cfg(windows)]
+pub mod msvcrt;
+#[cfg(windows)]
+pub mod nt;
+#[cfg(windows)]
+pub mod winapi;
diff --git a/crates/common/src/macros.rs → crates/host_env/src/macros.rs b/crates/common/src/macros.rs → crates/host_env/src/macros.rs