ctypes: fix Windows pip truststore (#8314)

* ctypes: preserve result when errcheck returns args

* ctypes: cover Windows pip truststore

* capi: implement PyEval_SaveThread

* capi: merge saved thread state into PyThreadState

.github/workflows/ci.yaml

@@ -438,6 +438,17 @@ jobs:
           target/release/rustpython -m ensurepip
           target/release/rustpython -c "import pip"
 
+      - if: runner.os == 'Windows'
+        name: Check pip HTTPS with the Windows trust store
+        run: >-
+          target/release/rustpython -m pip download
+          --disable-pip-version-check
+          --no-cache-dir
+          --no-deps
+          --only-binary=:all:
+          --dest "$env:RUNNER_TEMP\rustpython-pip-smoke"
+          six
+
       - if: runner.os != 'Windows'
         name: Check if pip inside venv is functional
         run: |
@@ -829,4 +840,3 @@ jobs:
 
       - name: cargo doc
         run: cargo doc --locked
-

crates/capi/src/pystate.rs

@@ -2,9 +2,9 @@ use crate::get_main_interpreter;
 use crate::pylifecycle::request_vm_from_interpreter;
 use crate::util::FfiResult;
 use core::ffi::c_int;
-use core::ptr;
 use rustpython_vm::vm::thread::{
-    CurrentVmAttachState, attach_current_thread, release_current_thread, with_current_vm,
+    CurrentVmAttachState, SavedThreadState, attach_current_thread, release_current_thread,
+    restore_current_thread, save_current_thread, with_current_vm,
 };
 use rustpython_vm::{Interpreter, VirtualMachine};
 
@@ -22,6 +22,7 @@ pub type PyInterpreterState = Interpreter;
 #[repr(C)]
 pub struct PyThreadState {
     pub interp: *mut PyInterpreterState,
+    vm: SavedThreadState,
 }
 
 /// Make sure this thread has a running vm attached. This only creates a new vm if we don't already
@@ -47,11 +48,22 @@ pub extern "C" fn PyGILState_Release(state: PyGILState_STATE) {
 
 #[unsafe(no_mangle)]
 pub extern "C" fn PyEval_SaveThread() -> *mut PyThreadState {
-    ptr::null_mut()
+    let interp = PyInterpreterState_Get();
+    let state = Box::new(PyThreadState {
+        interp,
+        vm: save_current_thread(),
+    });
+    Box::into_raw(state)
 }
 
 #[unsafe(no_mangle)]
-pub extern "C" fn PyEval_RestoreThread(_state: *mut PyThreadState) {}
+pub unsafe extern "C" fn PyEval_RestoreThread(state: *mut PyThreadState) {
+    assert!(!state.is_null(), "PyEval_RestoreThread called with null");
+    // SAFETY: PyEval_SaveThread returns this allocation and CPython's API
+    // requires callers to restore exactly that thread state once.
+    let state = unsafe { Box::from_raw(state) };
+    restore_current_thread(state.vm);
+}
 
 #[unsafe(no_mangle)]
 pub extern "C" fn PyInterpreterState_Get() -> *mut PyInterpreterState {
@@ -81,7 +93,7 @@ mod tests {
 
     #[test]
     fn new_thread() {
-        Python::attach(|_py| {
+        Python::attach(|py| {
             with_current_vm(|_vm| {
                 assert!(
                     current_vm_is_set(),
@@ -89,18 +101,24 @@ mod tests {
                 )
             });
 
-            std::thread::spawn(move || {
+            let handle = std::thread::spawn(move || {
                 Python::attach(|_py| {
-                    with_current_vm(|_vm| {
+                    with_current_vm(|vm| {
                         assert!(
                             current_vm_is_set(),
                             "This thread did not have a vm attached"
-                        )
+                        );
+                        vm.state.stop_the_world.stop_the_world(vm);
+                        vm.state.stop_the_world.start_the_world(vm);
                     });
                 });
-            })
-            .join()
-            .unwrap();
+            });
+
+            py.detach(|| {
+                assert!(!current_vm_is_set());
+                handle.join().unwrap();
+            });
+            assert!(current_vm_is_set());
         })
     }
 

crates/stdlib/src/overlapped.rs

@@ -1163,7 +1163,8 @@ mod _overlapped {
 
     #[pyfunction]
     fn GetQueuedCompletionStatus(port: isize, msecs: u32, vm: &VirtualMachine) -> PyResult {
-        match host_overlapped::get_queued_completion_status(port, msecs)
+        match vm
+            .allow_threads(|| host_overlapped::get_queued_completion_status(port, msecs))
             .map_err(|err| set_from_windows_err(err.raw_os_error().unwrap_or(0) as u32, vm))?
         {
             host_overlapped::WaitResult::Timeout => Ok(vm.ctx.none()),

crates/vm/src/stdlib/_ctypes/array.rs

@@ -641,6 +641,14 @@ impl PyCArray {
                     let (kept_alive, ptr) = super::base::ensure_z_null_terminated(bytes, vm);
                     zelf.0.keep_alive(index, kept_alive);
                     (ptr, Some(value.to_owned()))
+                } else if let Some(simple) = value.downcast_ref::<super::PyCSimple>()
+                    && value.class().type_code(vm).as_deref() == Some("z")
+                {
+                    let buffer = simple.0.buffer.read();
+                    (
+                        rustpython_host_env::ctypes::read_pointer_from_buffer(&buffer),
+                        None,
+                    )
                 } else if let Ok(int_val) = value.try_index(vm) {
                     (int_val.as_bigint().to_usize().unwrap_or(0), None)
                 } else {
@@ -667,6 +675,14 @@ impl PyCArray {
                 } else if let Some(s) = value.downcast_ref::<PyStr>() {
                     let (holder, ptr) = super::base::str_to_wchar_bytes(s.as_wtf8(), vm);
                     (ptr, Some(holder))
+                } else if let Some(simple) = value.downcast_ref::<super::PyCSimple>()
+                    && value.class().type_code(vm).as_deref() == Some("Z")
+                {
+                    let buffer = simple.0.buffer.read();
+                    (
+                        rustpython_host_env::ctypes::read_pointer_from_buffer(&buffer),
+                        None,
+                    )
                 } else if let Ok(int_val) = value.try_index(vm) {
                     (int_val.as_bigint().to_usize().unwrap_or(0), None)
                 } else {

crates/vm/src/stdlib/_ctypes/function.rs

@@ -1554,7 +1554,11 @@ fn build_result(
         let args_tuple = PyTuple::new_ref(args.args.clone(), &vm.ctx);
         let func_obj = zelf.as_object().to_owned();
         let result_obj = result.clone().unwrap_or_else(|| vm.ctx.none());
-        result = Some(errcheck.call((result_obj, func_obj, args_tuple), vm)?);
+        let checked = errcheck.call((result_obj, func_obj, args_tuple.clone()), vm)?;
+        // Returning the original args tuple requests normal result processing.
+        if !checked.is(&args_tuple) {
+            result = Some(checked);
+        }
     }
 
     // Handle OUT parameter return values

crates/vm/src/vm/thread.rs

@@ -224,6 +224,61 @@ pub enum CurrentVmAttachState {
     Attached,
 }
 
+/// State preserved while the current native thread is detached from its VM.
+#[cfg(feature = "threading")]
+pub struct SavedThreadState {
+    vm_stack: Vec<NonNull<VirtualMachine>>,
+    gilstate_vm: Option<Box<ThreadedVirtualMachine>>,
+}
+
+/// Detach the current native thread and preserve its VM context for restoration.
+#[cfg(feature = "threading")]
+#[must_use = "the saved thread state must be restored"]
+pub fn save_current_thread() -> SavedThreadState {
+    let vm_stack = VM_STACK.with(|vms| core::mem::take(&mut *vms.borrow_mut()));
+    assert!(
+        !vm_stack.is_empty(),
+        "save_current_thread() called without an attached VM"
+    );
+    let gilstate_vm = GILSTATE_VM.with(|gilstate_vm| gilstate_vm.borrow_mut().take());
+    detach_thread();
+    SavedThreadState {
+        vm_stack,
+        gilstate_vm,
+    }
+}
+
+/// Restore a VM context previously returned by [`save_current_thread`].
+#[cfg(feature = "threading")]
+pub fn restore_current_thread(state: SavedThreadState) {
+    assert!(
+        !current_vm_is_set(),
+        "restore_current_thread() called with an attached VM"
+    );
+    let SavedThreadState {
+        vm_stack,
+        gilstate_vm,
+    } = state;
+    let vm = vm_stack
+        .last()
+        .copied()
+        .expect("saved thread state has no VM");
+
+    GILSTATE_VM.with(|current| {
+        let mut current = current.borrow_mut();
+        assert!(
+            current.is_none(),
+            "restore_current_thread() called with a GILState VM"
+        );
+        *current = gilstate_vm;
+    });
+
+    // SAFETY: borrowed VMs remain alive for the dynamic save/restore scope,
+    // while an owned GILState VM was restored above before this dereference.
+    attach_thread(unsafe { vm.as_ref() });
+    VM_STACK.with(|vms| *vms.borrow_mut() = vm_stack);
+}
+
 /// Attach the current native thread to a RustPython VM until
 /// `release_current_thread()` is called.
 #[cfg(feature = "threading")]

extra_tests/snippets/stdlib_ctypes.py

@@ -190,6 +190,10 @@ class c_char_p(_SimpleCData):
 
 _check_size(c_char_p, "P")
 
+char_pointer = c_char_p(b"1.3.6.1.5.5.7.3.1")
+char_pointer_array = (c_char_p * 1)(char_pointer)
+assert char_pointer_array[0] == b"1.3.6.1.5.5.7.3.1"
+
 
 class c_void_p(_SimpleCData):
     _type_ = "P"
@@ -344,7 +348,9 @@ if _os.name == "posix":
         # print(libc.srand(i))
         # print(test_byte_array)
 else:
+    import ctypes
     import os
+    from ctypes import wintypes
 
     libc = cdll.msvcrt
     libc.rand()
@@ -356,6 +362,29 @@ else:
     # print("start printf")
     # libc.printf(test_byte_array)
 
+    kernel32 = ctypes.WinDLL("kernel32", use_last_error=True)
+    get_current_process = kernel32.GetCurrentProcess
+    get_current_process.argtypes = ()
+    get_current_process.restype = ctypes.c_void_p
+
+    def preserve_result(_result, _func, args):
+        return args
+
+    get_current_process.errcheck = preserve_result
+    process_handle = get_current_process()
+    assert isinstance(process_handle, int)
+
+    get_process_id = kernel32.GetProcessId
+    get_process_id.argtypes = (ctypes.c_void_p,)
+    get_process_id.restype = wintypes.DWORD
+    assert get_process_id(process_handle) == os.getpid()
+
+    def replace_result(_result, _func, _args):
+        return "replacement"
+
+    get_current_process.errcheck = replace_result
+    assert get_current_process() == "replacement"
+
     # windows pip support
 
     def get_win_folder_via_ctypes(csidl_name: str) -> str:
@@ -364,8 +393,6 @@ else:
         # Use 'CSIDL_PROFILE' (40) and append the default folder 'Downloads' instead.
         # https://learn.microsoft.com/en-us/windows/win32/shell/knownfolderid
 
-        import ctypes  # noqa: PLC0415
-
         csidl_const = {
             "CSIDL_APPDATA": 26,
             "CSIDL_COMMON_APPDATA": 35,