From f4d39134b8daefb5ab0db6750a203f980eecb4f0 Mon Sep 17 00:00:00 2001
From: Jan Kotas <jkotas@microsoft.com>
Date: Fri, 10 Jul 2020 06:41:34 -0700
Subject: [PATCH] Simplify IsWow64Process interop (#39059)

Fixes #38910
---
 .../src/System.Diagnostics.Process.csproj          |  2 ++
 .../src/System/Diagnostics/ProcessManager.Win32.cs | 33 +++++++---------------
 2 files changed, 12 insertions(+), 23 deletions(-)

diff --git a/src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj b/src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj
index c7165ca..7c759f4 100644
--- a/src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj
+++ b/src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj
@@ -82,6 +82,8 @@
              Link="Common\Interop\Windows\Kernel32\Interop.CloseHandle.cs" />
     <Compile Include="$(CommonPath)Interop\Windows\Advapi32\Interop.PERF_INFO.cs"
              Link="Common\Interop\Windows\Advapi32\Interop.PERF_INFO.cs" />
+    <Compile Include="$(CommonPath)Interop\Windows\Kernel32\Interop.IsWow64Process_IntPtr.cs"
+             Link="Common\Interop\Windows\Kernel32\Interop.IsWow64Process_IntPtr.cs" />
     <Compile Include="$(CommonPath)Interop\Windows\Kernel32\Interop.IsWow64Process_SafeProcessHandle.cs"
              Link="Common\Interop\Windows\Kernel32\Interop.IsWow64Process_SafeProcessHandle.cs" />
     <Compile Include="$(CommonPath)Interop\Windows\Kernel32\Interop.GetExitCodeProcess.cs"
diff --git a/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessManager.Win32.cs b/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessManager.Win32.cs
index 38512de..fa17d76 100644
--- a/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessManager.Win32.cs
+++ b/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessManager.Win32.cs
@@ -93,33 +93,20 @@ namespace System.Diagnostics
                 // do the enumeration at all.  So we'll detect this case and bail out.
                 if (!succeeded)
                 {
-                    SafeProcessHandle hCurProcess = SafeProcessHandle.InvalidHandle;
-                    try
+                    if (!Interop.Kernel32.IsWow64Process(Interop.Kernel32.GetCurrentProcess(), out bool sourceProcessIsWow64))
                     {
-                        hCurProcess = ProcessManager.OpenProcess(Environment.ProcessId, Interop.Advapi32.ProcessOptions.PROCESS_QUERY_INFORMATION, true);
-
-                        if (!Interop.Kernel32.IsWow64Process(hCurProcess, out bool sourceProcessIsWow64))
-                        {
-                            throw new Win32Exception();
-                        }
-
-                        if (!Interop.Kernel32.IsWow64Process(processHandle, out bool targetProcessIsWow64))
-                        {
-                            throw new Win32Exception();
-                        }
+                        throw new Win32Exception();
+                    }
 
-                        if (sourceProcessIsWow64 && !targetProcessIsWow64)
-                        {
-                            // Wow64 isn't going to allow this to happen, the best we can do is give a descriptive error to the user.
-                            throw new Win32Exception(Interop.Errors.ERROR_PARTIAL_COPY, SR.EnumProcessModuleFailedDueToWow);
-                        }
+                    if (!Interop.Kernel32.IsWow64Process(processHandle, out bool targetProcessIsWow64))
+                    {
+                        throw new Win32Exception();
                     }
-                    finally
+
+                    if (sourceProcessIsWow64 && !targetProcessIsWow64)
                     {
-                        if (hCurProcess != SafeProcessHandle.InvalidHandle)
-                        {
-                            hCurProcess.Dispose();
-                        }
+                        // Wow64 isn't going to allow this to happen, the best we can do is give a descriptive error to the user.
+                        throw new Win32Exception(Interop.Errors.ERROR_PARTIAL_COPY, SR.EnumProcessModuleFailedDueToWow);
                     }
 
                     EnumProcessModulesUntilSuccess(processHandle, null, 0, out needed);
-- 
2.7.4