Windows library loader: add support for hModule == 0

lostmsu · lostmsu · commit 1b887838fc2f · 2021-01-28T11:19:45.000-08:00
diff --git a/src/runtime/platform/LibraryLoader.cs b/src/runtime/platform/LibraryLoader.cs
@@ -1,5 +1,7 @@
 using System;
 using System.ComponentModel;
+using System.Diagnostics;
+using System.Linq;
 using System.Runtime.InteropServices;
 
 namespace Python.Runtime.Platform
@@ -195,6 +197,15 @@ public IntPtr Load(string dllToLoad)
 
         public IntPtr GetFunction(IntPtr hModule, string procedureName)
         {
+            if (hModule == IntPtr.Zero)
+            {
+                foreach(var module in GetAllModules())
+                {
+                    var func = GetProcAddress(module, procedureName);
+                    if (func != IntPtr.Zero) return func;
+                }
+            }
+
             var res = WindowsLoader.GetProcAddress(hModule, procedureName);
             if (res == IntPtr.Zero)
                 throw new MissingMethodException($"Failed to load symbol {procedureName}", new Win32Exception());
@@ -203,6 +214,24 @@ public IntPtr GetFunction(IntPtr hModule, string procedureName)
 
         public void Free(IntPtr hModule) => WindowsLoader.FreeLibrary(hModule);
 
+        static IntPtr[] GetAllModules()
+        {
+            var self = Process.GetCurrentProcess().Handle;
+
+            uint bytes = 0;
+            var result = new IntPtr[0];
+            if (!EnumProcessModules(self, result, bytes, out var needsBytes))
+                throw new Win32Exception();
+            while (bytes < needsBytes)
+            {
+                bytes = needsBytes;
+                result = new IntPtr[bytes / IntPtr.Size];
+                if (!EnumProcessModules(self, result, bytes, out needsBytes))
+                    throw new Win32Exception();
+            }
+            return result.Take((int)(needsBytes / IntPtr.Size)).ToArray();
+        }
+
         [DllImport(NativeDll, SetLastError = true)]
         static extern IntPtr LoadLibrary(string dllToLoad);
 
@@ -211,5 +240,8 @@ public IntPtr GetFunction(IntPtr hModule, string procedureName)
 
         [DllImport(NativeDll)]
         static extern bool FreeLibrary(IntPtr hModule);
+
+        [DllImport("Psapi.dll", SetLastError = true)]
+        static extern bool EnumProcessModules(IntPtr hProcess, [In, Out] IntPtr[] lphModule, uint lphModuleByteCount, out uint byteCountNeeded);
     }
 }
