From 572f3ba50bb11f29046c45ad82fb51c0a15ce032 Mon Sep 17 00:00:00 2001
From: Ashwin Naren <arihant2math@gmail.com>
Date: Wed, 12 Feb 2025 20:48:46 -0800
Subject: [PATCH] initial _ctypes implementation with _CData, get_errno, and
 set_errno

Signed-off-by: Ashwin Naren <arihant2math@gmail.com>
---
 Cargo.lock              |  5 +++--
 vm/Cargo.toml           |  1 +
 vm/src/stdlib/ctypes.rs | 34 ++++++++++++++++++++++++++++++++++
 vm/src/stdlib/mod.rs    |  6 ++++++
 4 files changed, 44 insertions(+), 2 deletions(-)
 create mode 100644 vm/src/stdlib/ctypes.rs

diff --git a/Cargo.lock b/Cargo.lock
index 8f4c765e023..97236f95ec8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1265,9 +1265,9 @@ checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
 
 [[package]]
 name = "memmap2"
-version = "0.9.5"
+version = "0.5.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fd3f7eed9d3848f8b98834af67102b720745c4ec028fcd0aa0239277e7de374f"
+checksum = "83faa42c0a078c393f6b29d5db232d8be22776a891f8f56e5284faee4a20b327"
 dependencies = [
  "libc",
 ]
@@ -2205,6 +2205,7 @@ dependencies = [
  "cfg-if",
  "chrono",
  "crossbeam-utils",
+ "errno",
  "exitcode",
  "flame",
  "flamer",
diff --git a/vm/Cargo.toml b/vm/Cargo.toml
index 6eaca281f86..0c992605ffa 100644
--- a/vm/Cargo.toml
+++ b/vm/Cargo.toml
@@ -99,6 +99,7 @@ uname = "0.1.1"
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 rustyline = { workspace = true }
 which = "6"
+errno = "0.3"
 
 [target.'cfg(any(not(target_arch = "wasm32"), target_os = "wasi"))'.dependencies]
 num_cpus = "1.13.1"
diff --git a/vm/src/stdlib/ctypes.rs b/vm/src/stdlib/ctypes.rs
new file mode 100644
index 00000000000..e0976fa4a69
--- /dev/null
+++ b/vm/src/stdlib/ctypes.rs
@@ -0,0 +1,34 @@
+pub(crate) use _ctypes::make_module;
+
+#[pymodule]
+mod _ctypes {
+    use crate::{common::lock::PyRwLock, PyObjectRef};
+    use crossbeam_utils::atomic::AtomicCell;
+
+    pub struct RawBuffer {
+        #[allow(dead_code)]
+        pub inner: Box<[u8]>,
+        #[allow(dead_code)]
+        pub size: usize,
+    }
+
+    #[pyattr]
+    #[pyclass(name = "_CData")]
+    pub struct PyCData {
+        _objects: AtomicCell<Vec<PyObjectRef>>,
+        _buffer: PyRwLock<RawBuffer>,
+    }
+
+    #[pyclass]
+    impl PyCData {}
+
+    #[pyfunction]
+    fn get_errno() -> i32 {
+        errno::errno().0
+    }
+
+    #[pyfunction]
+    fn set_errno(value: i32) {
+        errno::set_errno(errno::Errno(value));
+    }
+}
diff --git a/vm/src/stdlib/mod.rs b/vm/src/stdlib/mod.rs
index 12baee11f7a..ca8f8f0bfd8 100644
--- a/vm/src/stdlib/mod.rs
+++ b/vm/src/stdlib/mod.rs
@@ -37,6 +37,8 @@ pub mod posix;
 #[path = "posix_compat.rs"]
 pub mod posix;
 
+#[cfg(any(target_family = "unix", target_family = "windows"))]
+mod ctypes;
 #[cfg(windows)]
 pub(crate) mod msvcrt;
 #[cfg(all(unix, not(any(target_os = "android", target_os = "redox"))))]
@@ -124,5 +126,9 @@ pub fn get_module_inits() -> StdlibMap {
             "_winapi" => winapi::make_module,
             "winreg" => winreg::make_module,
         }
+        #[cfg(any(target_family = "unix", target_family = "windows"))]
+        {
+            "_ctypes" => ctypes::make_module,
+        }
     }
 }