Auto merge of rust-lang#114848 - michaelvanstraten:spawn_with_attributes, r=ChrisDenton

Add ability to spawn Windows process with Proc Thread Attributes | Take 2

This is the second attempt to merge pull request rust-lang#88193 into the standard library.

This PR implements the ability to add arbitrary attributes to a command on Windows targets using a new `raw_attribute` method on the [`CommandExt`](https://doc.rust-lang.org/stable/std/os/windows/process/trait.CommandExt.html) trait.

`@TyPR124` and my main motivation behind adding this feature is to enable the support of pseudo terminals in the std library, but there are many more applications. A good starting point to get into this topic is to head over to the [`Win32 API documentation`](https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-updateprocthreadattribute).

Author: bors

library/std/src/os/windows/process.rs

@@ -192,6 +192,66 @@ pub trait CommandExt: Sealed {
     /// ```
     #[unstable(feature = "windows_process_extensions_async_pipes", issue = "98289")]
     fn async_pipes(&mut self, always_async: bool) -> &mut process::Command;
+
+    /// Sets a raw attribute on the command, providing extended configuration options for Windows processes.
+    ///
+    /// This method allows you to specify custom attributes for a child process on Windows systems using raw attribute values.
+    /// Raw attributes provide extended configurability for process creation, but their usage can be complex and potentially unsafe.
+    ///
+    /// The `attribute` parameter specifies the raw attribute to be set, while the `value` parameter holds the value associated with that attribute.
+    /// Please refer to the [`windows-rs`](https://microsoft.github.io/windows-docs-rs/doc/windows/) documentation or the [`Win32 API documentation`](https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-updateprocthreadattribute) for detailed information about available attributes and their meanings.
+    ///
+    /// # Note
+    ///
+    /// The maximum number of raw attributes is the value of [`u32::MAX`].
+    /// If this limit is exceeded, the call to [`process::Command::spawn`] will return an `Error` indicating that the maximum number of attributes has been exceeded.
+    /// # Safety
+    ///
+    /// The usage of raw attributes is potentially unsafe and should be done with caution. Incorrect attribute values or improper configuration can lead to unexpected behavior or errors.
+    ///
+    /// # Example
+    ///
+    /// The following example demonstrates how to create a child process with a specific parent process ID using a raw attribute.
+    ///
+    /// ```rust
+    /// #![feature(windows_process_extensions_raw_attribute)]
+    /// use std::os::windows::{process::CommandExt, io::AsRawHandle};
+    /// use std::process::Command;
+    ///
+    /// # struct ProcessDropGuard(std::process::Child);
+    /// # impl Drop for ProcessDropGuard {
+    /// #     fn drop(&mut self) {
+    /// #         let _ = self.0.kill();
+    /// #     }
+    /// # }
+    ///
+    /// let parent = Command::new("cmd").spawn()?;
+    ///
+    /// let mut child_cmd = Command::new("cmd");
+    ///
+    /// const PROC_THREAD_ATTRIBUTE_PARENT_PROCESS: usize = 0x00020000;
+    ///
+    /// unsafe {
+    ///     child_cmd.raw_attribute(PROC_THREAD_ATTRIBUTE_PARENT_PROCESS, parent.as_raw_handle() as isize);
+    /// }
+    /// #
+    /// # let parent = ProcessDropGuard(parent);
+    ///
+    /// let mut child = child_cmd.spawn()?;
+    ///
+    /// # child.kill()?;
+    /// # Ok::<(), std::io::Error>(())
+    /// ```
+    ///
+    /// # Safety Note
+    ///
+    /// Remember that improper use of raw attributes can lead to undefined behavior or security vulnerabilities. Always consult the documentation and ensure proper attribute values are used.
+    #[unstable(feature = "windows_process_extensions_raw_attribute", issue = "114854")]
+    unsafe fn raw_attribute<T: Copy + Send + Sync + 'static>(
+        &mut self,
+        attribute: usize,
+        value: T,
+    ) -> &mut process::Command;
 }
 
 #[stable(feature = "windows_process_extensions", since = "1.16.0")]
@@ -219,6 +279,15 @@ impl CommandExt for process::Command {
         let _ = always_async;
         self
     }
+
+    unsafe fn raw_attribute<T: Copy + Send + Sync + 'static>(
+        &mut self,
+        attribute: usize,
+        value: T,
+    ) -> &mut process::Command {
+        self.as_inner_mut().raw_attribute(attribute, value);
+        self
+    }
 }
 
 #[unstable(feature = "windows_process_extensions_main_thread_handle", issue = "96723")]

library/std/src/process/tests.rs

@@ -434,6 +434,91 @@ fn test_creation_flags() {
     assert!(events > 0);
 }
 
+/// Tests proc thread attributes by spawning a process with a custom parent process,
+/// then comparing the parent process ID with the expected parent process ID.
+#[test]
+#[cfg(windows)]
+fn test_proc_thread_attributes() {
+    use crate::mem;
+    use crate::os::windows::io::AsRawHandle;
+    use crate::os::windows::process::CommandExt;
+    use crate::sys::c::{CloseHandle, BOOL, HANDLE};
+    use crate::sys::cvt;
+
+    #[repr(C)]
+    #[allow(non_snake_case)]
+    struct PROCESSENTRY32W {
+        dwSize: u32,
+        cntUsage: u32,
+        th32ProcessID: u32,
+        th32DefaultHeapID: usize,
+        th32ModuleID: u32,
+        cntThreads: u32,
+        th32ParentProcessID: u32,
+        pcPriClassBase: i32,
+        dwFlags: u32,
+        szExeFile: [u16; 260],
+    }
+
+    extern "system" {
+        fn CreateToolhelp32Snapshot(dwflags: u32, th32processid: u32) -> HANDLE;
+        fn Process32First(hsnapshot: HANDLE, lppe: *mut PROCESSENTRY32W) -> BOOL;
+        fn Process32Next(hsnapshot: HANDLE, lppe: *mut PROCESSENTRY32W) -> BOOL;
+    }
+
+    const PROC_THREAD_ATTRIBUTE_PARENT_PROCESS: usize = 0x00020000;
+    const TH32CS_SNAPPROCESS: u32 = 0x00000002;
+
+    struct ProcessDropGuard(crate::process::Child);
+
+    impl Drop for ProcessDropGuard {
+        fn drop(&mut self) {
+            let _ = self.0.kill();
+        }
+    }
+
+    let parent = ProcessDropGuard(Command::new("cmd").spawn().unwrap());
+
+    let mut child_cmd = Command::new("cmd");
+
+    unsafe {
+        child_cmd
+            .raw_attribute(PROC_THREAD_ATTRIBUTE_PARENT_PROCESS, parent.0.as_raw_handle() as isize);
+    }
+
+    let child = ProcessDropGuard(child_cmd.spawn().unwrap());
+
+    let h_snapshot = unsafe { CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0) };
+
+    let mut process_entry = PROCESSENTRY32W {
+        dwSize: mem::size_of::<PROCESSENTRY32W>() as u32,
+        cntUsage: 0,
+        th32ProcessID: 0,
+        th32DefaultHeapID: 0,
+        th32ModuleID: 0,
+        cntThreads: 0,
+        th32ParentProcessID: 0,
+        pcPriClassBase: 0,
+        dwFlags: 0,
+        szExeFile: [0; 260],
+    };
+
+    unsafe { cvt(Process32First(h_snapshot, &mut process_entry as *mut _)) }.unwrap();
+
+    loop {
+        if child.0.id() == process_entry.th32ProcessID {
+            break;
+        }
+        unsafe { cvt(Process32Next(h_snapshot, &mut process_entry as *mut _)) }.unwrap();
+    }
+
+    unsafe { cvt(CloseHandle(h_snapshot)) }.unwrap();
+
+    assert_eq!(parent.0.id(), process_entry.th32ParentProcessID);
+
+    drop(child)
+}
+
 #[test]
 fn test_command_implements_send_sync() {
     fn take_send_sync_type<T: Send + Sync>(_: T) {}

library/std/src/sys/windows/c/windows_sys.lst

@@ -2510,6 +2510,7 @@ Windows.Win32.System.Threading.CreateProcessW
 Windows.Win32.System.Threading.CreateThread
 Windows.Win32.System.Threading.DEBUG_ONLY_THIS_PROCESS
 Windows.Win32.System.Threading.DEBUG_PROCESS
+Windows.Win32.System.Threading.DeleteProcThreadAttributeList
 Windows.Win32.System.Threading.DETACHED_PROCESS
 Windows.Win32.System.Threading.ExitProcess
 Windows.Win32.System.Threading.EXTENDED_STARTUPINFO_PRESENT
@@ -2524,8 +2525,10 @@ Windows.Win32.System.Threading.INFINITE
 Windows.Win32.System.Threading.INHERIT_CALLER_PRIORITY
 Windows.Win32.System.Threading.INHERIT_PARENT_AFFINITY
 Windows.Win32.System.Threading.INIT_ONCE_INIT_FAILED
+Windows.Win32.System.Threading.InitializeProcThreadAttributeList
 Windows.Win32.System.Threading.InitOnceBeginInitialize
 Windows.Win32.System.Threading.InitOnceComplete
+Windows.Win32.System.Threading.LPPROC_THREAD_ATTRIBUTE_LIST
 Windows.Win32.System.Threading.LPTHREAD_START_ROUTINE
 Windows.Win32.System.Threading.NORMAL_PRIORITY_CLASS
 Windows.Win32.System.Threading.OpenProcessToken
@@ -2561,6 +2564,7 @@ Windows.Win32.System.Threading.STARTF_USEPOSITION
 Windows.Win32.System.Threading.STARTF_USESHOWWINDOW
 Windows.Win32.System.Threading.STARTF_USESIZE
 Windows.Win32.System.Threading.STARTF_USESTDHANDLES
+Windows.Win32.System.Threading.STARTUPINFOEXW
 Windows.Win32.System.Threading.STARTUPINFOW
 Windows.Win32.System.Threading.STARTUPINFOW_FLAGS
 Windows.Win32.System.Threading.SwitchToThread
@@ -2575,6 +2579,7 @@ Windows.Win32.System.Threading.TlsGetValue
 Windows.Win32.System.Threading.TlsSetValue
 Windows.Win32.System.Threading.TryAcquireSRWLockExclusive
 Windows.Win32.System.Threading.TryAcquireSRWLockShared
+Windows.Win32.System.Threading.UpdateProcThreadAttribute
 Windows.Win32.System.Threading.WaitForMultipleObjects
 Windows.Win32.System.Threading.WaitForSingleObject
 Windows.Win32.System.Threading.WakeAllConditionVariable

library/std/src/sys/windows/c/windows_sys.rs

@@ -155,6 +155,10 @@ extern "system" {
     pub fn DeleteFileW(lpfilename: PCWSTR) -> BOOL;
 }
 #[link(name = "kernel32")]
+extern "system" {
+    pub fn DeleteProcThreadAttributeList(lpattributelist: LPPROC_THREAD_ATTRIBUTE_LIST) -> ();
+}
+#[link(name = "kernel32")]
 extern "system" {
     pub fn DeviceIoControl(
         hdevice: HANDLE,
@@ -371,6 +375,15 @@ extern "system" {
     ) -> BOOL;
 }
 #[link(name = "kernel32")]
+extern "system" {
+    pub fn InitializeProcThreadAttributeList(
+        lpattributelist: LPPROC_THREAD_ATTRIBUTE_LIST,
+        dwattributecount: u32,
+        dwflags: u32,
+        lpsize: *mut usize,
+    ) -> BOOL;
+}
+#[link(name = "kernel32")]
 extern "system" {
     pub fn MoveFileExW(
         lpexistingfilename: PCWSTR,
@@ -543,6 +556,18 @@ extern "system" {
     pub fn TryAcquireSRWLockShared(srwlock: *mut RTL_SRWLOCK) -> BOOLEAN;
 }
 #[link(name = "kernel32")]
+extern "system" {
+    pub fn UpdateProcThreadAttribute(
+        lpattributelist: LPPROC_THREAD_ATTRIBUTE_LIST,
+        dwflags: u32,
+        attribute: usize,
+        lpvalue: *const ::core::ffi::c_void,
+        cbsize: usize,
+        lppreviousvalue: *mut ::core::ffi::c_void,
+        lpreturnsize: *const usize,
+    ) -> BOOL;
+}
+#[link(name = "kernel32")]
 extern "system" {
     pub fn WaitForMultipleObjects(
         ncount: u32,
@@ -3567,6 +3592,7 @@ pub type LPOVERLAPPED_COMPLETION_ROUTINE = ::core::option::Option<
         lpoverlapped: *mut OVERLAPPED,
     ) -> (),
 >;
+pub type LPPROC_THREAD_ATTRIBUTE_LIST = *mut ::core::ffi::c_void;
 pub type LPPROGRESS_ROUTINE = ::core::option::Option<
     unsafe extern "system" fn(
         totalfilesize: i64,
@@ -3833,6 +3859,17 @@ pub const STARTF_USESHOWWINDOW: STARTUPINFOW_FLAGS = 1u32;
 pub const STARTF_USESIZE: STARTUPINFOW_FLAGS = 2u32;
 pub const STARTF_USESTDHANDLES: STARTUPINFOW_FLAGS = 256u32;
 #[repr(C)]
+pub struct STARTUPINFOEXW {
+    pub StartupInfo: STARTUPINFOW,
+    pub lpAttributeList: LPPROC_THREAD_ATTRIBUTE_LIST,
+}
+impl ::core::marker::Copy for STARTUPINFOEXW {}
+impl ::core::clone::Clone for STARTUPINFOEXW {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+#[repr(C)]
 pub struct STARTUPINFOW {
     pub cb: u32,
     pub lpReserved: PWSTR,