1 files changed, 99 insertions, 0 deletions
diff --git a/manager/uiprocess.go b/manager/uiprocess.go
new file mode 100644
index 00000000..80ac8b30
--- /dev/null
+++ b/manager/uiprocess.go
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package manager
+
+import (
+	"errors"
+	"runtime"
+	"sync/atomic"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+type uiProcess struct {
+	handle uintptr
+}
+
+func launchUIProcess(executable string, args []string, workingDirectory string, handles []windows.Handle, token windows.Token) (*uiProcess, error) {
+	executable16, err := windows.UTF16PtrFromString(executable)
+	if err != nil {
+		return nil, err
+	}
+	args16, err := windows.UTF16PtrFromString(windows.ComposeCommandLine(args))
+	if err != nil {
+		return nil, err
+	}
+	workingDirectory16, err := windows.UTF16PtrFromString(workingDirectory)
+	if err != nil {
+		return nil, err
+	}
+	var environmentBlock *uint16
+	err = windows.CreateEnvironmentBlock(&environmentBlock, token, false)
+	if err != nil {
+		return nil, err
+	}
+	defer windows.DestroyEnvironmentBlock(environmentBlock)
+	attributeList, err := windows.NewProcThreadAttributeList(1)
+	if err != nil {
+		return nil, err
+	}
+	defer attributeList.Delete()
+	si := &windows.StartupInfoEx{
+		StartupInfo:             windows.StartupInfo{Cb: uint32(unsafe.Sizeof(windows.StartupInfoEx{}))},
+		ProcThreadAttributeList: attributeList.List(),
+	}
+	if len(handles) == 0 {
+		handles = []windows.Handle{0}
+	}
+	attributeList.Update(windows.PROC_THREAD_ATTRIBUTE_HANDLE_LIST, unsafe.Pointer(&handles[0]), uintptr(len(handles))*unsafe.Sizeof(handles[0]))
+	pi := new(windows.ProcessInformation)
+	err = windows.CreateProcessAsUser(token, executable16, args16, nil, nil, true, windows.CREATE_DEFAULT_ERROR_MODE|windows.CREATE_UNICODE_ENVIRONMENT|windows.EXTENDED_STARTUPINFO_PRESENT, environmentBlock, workingDirectory16, &si.StartupInfo, pi)
+	if err != nil {
+		return nil, err
+	}
+	windows.CloseHandle(pi.Thread)
+	uiProc := &uiProcess{handle: uintptr(pi.Process)}
+	runtime.SetFinalizer(uiProc, (*uiProcess).release)
+	return uiProc, nil
+}
+
+func (p *uiProcess) release() error {
+	handle := windows.Handle(atomic.SwapUintptr(&p.handle, uintptr(windows.InvalidHandle)))
+	if handle == windows.InvalidHandle {
+		return nil
+	}
+	err := windows.CloseHandle(handle)
+	if err != nil {
+		return err
+	}
+	runtime.SetFinalizer(p, nil)
+	return nil
+}
+
+func (p *uiProcess) Wait() (uint32, error) {
+	handle := windows.Handle(atomic.LoadUintptr(&p.handle))
+	s, err := windows.WaitForSingleObject(handle, syscall.INFINITE)
+	switch s {
+	case windows.WAIT_OBJECT_0:
+	case windows.WAIT_FAILED:
+		return 0, err
+	default:
+		return 0, errors.New("unexpected result from WaitForSingleObject")
+	}
+	var exitCode uint32
+	err = windows.GetExitCodeProcess(handle, &exitCode)
+	if err != nil {
+		return 0, err
+	}
+	p.release()
+	return exitCode, nil
+}
+
+func (p *uiProcess) Kill() error {
+	return windows.TerminateProcess(windows.Handle(atomic.LoadUintptr(&p.handle)), 1)
+}