Applying: Fix Windows 7 crash after connecting when Python plugin init fails

.github/workflows/windows-build.yml

@@ -126,11 +126,12 @@ jobs:
           $pyRoot = $env:pythonLocation
           if (-not $pyRoot) { $pyRoot = & python -c "import sys; print(sys.prefix)" }
 
-          $pyDir = "C:\gtk-build\python-3.8"
+          foreach ($pyDir in @("C:\gtk-build\python-3.8.10", "C:\gtk-build\python-3.8")) {
             New-Item -Path $pyDir -ItemType Directory -Force | Out-Null
             $target = Join-Path $pyDir "${{ matrix.platform }}"
             if (Test-Path $target) { Remove-Item $target -Recurse -Force }
             New-Item -Path $pyDir -Name "${{ matrix.platform }}" -ItemType Junction -Value $pyRoot | Out-Null
+          }
 
       - name: Build
         run: |
@@ -143,23 +144,33 @@ jobs:
             exit /b 1
           )
 
-          set "LIB=%PYTHON_DIR%\libs;%LIB%"
-          set "INCLUDE=%PYTHON_DIR%\include;%INCLUDE%"
-
-          powershell -NoProfile -ExecutionPolicy Bypass -Command "$archiveLib='C:\gtk-build\gtk\x64\release\lib\libarchive.lib'; if (-not (Test-Path $archiveLib)) { $archiveDll = Get-ChildItem 'C:\gtk-build\gtk\x64\release\bin\libarchive*.dll' | Select-Object -First 1; if ($archiveDll) { Push-Location 'C:\gtk-build\gtk\x64\release\lib'; & 'C:\gtk-build\gendef\gendef.exe' $archiveDll.FullName | Out-Null; $archiveDef = Get-ChildItem 'libarchive*.def' | Select-Object -First 1; if ($archiveDef) { & lib /def:$archiveDef.Name /machine:${{ matrix.platform }} /out:libarchive.lib | Out-Null }; Pop-Location } }"
-
-          msbuild win32\zoitechat.sln /m /verbosity:minimal /p:Configuration=Release /p:Platform=${{ matrix.platform }}
-
           set "PYTHON38_DIR=C:\gtk-build\python-3.8\${{ matrix.platform }}"
           if not exist "%PYTHON38_DIR%\libs\python38.lib" (
             echo Missing %PYTHON38_DIR%\libs\python38.lib
             dir "%PYTHON38_DIR%\libs"
             exit /b 1
           )
+          if not exist "%PYTHON38_DIR%\Lib\site-packages\_cffi_backend.cp38*.pyd" (
+            echo Missing %PYTHON38_DIR%\Lib\site-packages\_cffi_backend.cp38*.pyd
+            exit /b 1
+          )
 
-          msbuild plugins\python\python3.vcxproj /m /verbosity:minimal /p:Configuration=Release /p:Platform=${{ matrix.platform }} /p:SolutionDir=%CD%\win32\ /p:YourPython3Path=C:\gtk-build\python-3.8 /p:Python3Lib=python38 /p:Python3Output=hcpython38
+          set "LIB=%PYTHON_DIR%\libs;%LIB%"
-          copy /Y "%PYTHON38_DIR%\Lib\site-packages\_cffi_backend.cp38*.pyd" "..\zoitechat-build\${{ matrix.platform }}\bin\"
+          set "INCLUDE=%PYTHON_DIR%\include;%INCLUDE%"
-          msbuild win32\installer\installer.vcxproj /m /verbosity:minimal /p:Configuration=Release /p:Platform=${{ matrix.platform }} /p:SolutionDir=%CD%\win32\
+
+          powershell -NoProfile -ExecutionPolicy Bypass -Command "$archiveLib='C:\gtk-build\gtk\x64\release\lib\libarchive.lib'; if (-not (Test-Path $archiveLib)) { $archiveDll = Get-ChildItem 'C:\gtk-build\gtk\x64\release\bin\libarchive*.dll' | Select-Object -First 1; if ($archiveDll) { Push-Location 'C:\gtk-build\gtk\x64\release\lib'; & 'C:\gtk-build\gendef\gendef.exe' $archiveDll.FullName | Out-Null; $archiveDef = Get-ChildItem 'libarchive*.def' | Select-Object -First 1; if ($archiveDef) { & lib /def:$archiveDef.Name /machine:${{ matrix.platform }} /out:libarchive.lib | Out-Null }; Pop-Location } }"
+
+          msbuild win32\zoitechat.sln /m /verbosity:minimal /p:Configuration=Release /p:Platform=${{ matrix.platform }}
+          if errorlevel 1 exit /b 1
+
+          if not exist "..\zoitechat-build\${{ matrix.platform }}\rel\plugins\hcpython38.dll" (
+            echo hcpython38.dll was not built
+            exit /b 1
+          )
+          if not exist "..\zoitechat-build\${{ matrix.platform }}\rel\_cffi_backend.cp38*.pyd" (
+            echo _cffi_backend for Python 3.8 was not staged for the installer
+            exit /b 1
+          )
         shell: cmd
 
       - name: Preparing Artifacts

plugins/python/generate_plugin.py

@@ -53,6 +53,16 @@ builder.set_source('_zoitechat_embedded', '''
 #include "config.h"
 #include "zoitechat-plugin.h"
 
+#ifdef _WIN32
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#ifndef NOMINMAX
+#define NOMINMAX
+#endif
+#include <windows.h>
+#endif
+
 static zoitechat_plugin *ph;
 CFFI_DLLEXPORT int _on_plugin_init(char **, char **, char **, char *, char *);
 CFFI_DLLEXPORT int _on_plugin_deinit(void);
@@ -61,6 +71,20 @@ int zoitechat_plugin_init(zoitechat_plugin *plugin_handle,
                         char **name_out, char **description_out,
                         char **version_out, char *arg)
 {
+#ifdef _WIN32
+    /* CPython cannot be removed from a process once Py_Initialize has run.
+       If the embedded interpreter fails to start (e.g. _cffi_backend is
+       missing), the host responds to our 0 return by g_module_close()ing
+       this plugin, which would also drop the last reference to pythonXY.dll
+       and unload it mid-flight; the leftover process-global state then
+       crashes the process later, e.g. when a server connection spawns the
+       next thread.  Pin this module so FreeLibrary can never unload it. */
+    HMODULE self_handle;
+    GetModuleHandleExW (GET_MODULE_HANDLE_EX_FLAG_PIN |
+                        GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
+                        (LPCWSTR)&zoitechat_plugin_init, &self_handle);
+#endif
+
     if (ph != NULL)
     {
         puts ("Python plugin already loaded\\n");

src/common/plugin.c

@@ -59,18 +59,32 @@ typedef struct session zoitechat_context;
 #define DEBUG(x) {x;}
 #ifdef WIN32
 
+/* Python >= 3.9 dropped support for Windows versions before 10, so those
+ * systems get a Python 3.8 build of the plugin instead.  RtlGetVersion is
+ * used because GetVersionEx reports a version capped by the compatibility
+ * manifest rather than the real one. */
 static gboolean
-plugin_windows_is_windows7 (void)
+plugin_windows_needs_python38 (void)
 {
-	OSVERSIONINFOEXA version;
+	typedef LONG (WINAPI *rtl_get_version_func) (PRTL_OSVERSIONINFOW);
+	rtl_get_version_func rtl_get_version;
+	RTL_OSVERSIONINFOW version;
+	HMODULE ntdll;
+
+	ntdll = GetModuleHandleW (L"ntdll.dll");
+	if (ntdll == NULL)
+		return FALSE;
+
+	rtl_get_version = (rtl_get_version_func) GetProcAddress (ntdll, "RtlGetVersion");
+	if (rtl_get_version == NULL)
+		return FALSE;
 
 	memset (&version, 0, sizeof (version));
 	version.dwOSVersionInfoSize = sizeof (version);
-	if (!GetVersionExA ((OSVERSIONINFOA *)&version))
+	if (rtl_get_version (&version) != 0)
 		return FALSE;
 
-	return version.dwPlatformId == VER_PLATFORM_WIN32_NT &&
+	return version.dwMajorVersion < 10;
-		version.dwMajorVersion == 6 && version.dwMinorVersion == 1;
 }
 #endif
 
@@ -508,7 +522,7 @@ plugin_auto_load (session *sess)
 	for_files (lib_dir, "hcfishlim.dll", plugin_auto_load_cb);
 	for_files(lib_dir, "hclua.dll", plugin_auto_load_cb);
 	for_files (lib_dir, "hcperl.dll", plugin_auto_load_cb);
-	if (plugin_windows_is_windows7 ())
+	if (plugin_windows_needs_python38 ())
 		for_files (lib_dir, "hcpython38.dll", plugin_auto_load_cb);
 	else
 		for_files (lib_dir, "hcpython3.dll", plugin_auto_load_cb);

win32/installer/zoitechat.iss.tt

@@ -59,7 +59,7 @@ Name: "plugins\upd"; Description: "Update Checker"; Types: normal custom; Flags:
 Name: "langs"; Description: "Language Interfaces"; Types: custom; Flags: disablenouninstallwarning
 Name: "langs\lua"; Description: "Lua (LuaJIT 2.1)"; Types: normal custom; Flags: disablenouninstallwarning
 Name: "langs\perl"; Description: "Perl (Strawberry Perl 5.42.0.1)"; Types: custom; Flags: disablenouninstallwarning
-Name: "langs\python"; Description: "Python (Python 3.14.3, or 3.8.10 on Windows 7)"; Types: custom; Flags: disablenouninstallwarning
+Name: "langs\python"; Description: "Python (Python 3.14.3, or 3.8.10 before Windows 10)"; Types: custom; Flags: disablenouninstallwarning
 Name: "themes"; Description: "GTK3 Themes"; Types: normal minimal custom; Flags: disablenouninstallwarning
 Name: "themes\windows10"; Description: "Windows 10"; Types: normal minimal custom; Flags: disablenouninstallwarning
 Name: "themes\windows10dark"; Description: "Windows 10 Dark"; Types: normal minimal custom; Flags: disablenouninstallwarning
@@ -181,8 +181,8 @@ Source: "plugins\hcperl.dll"; DestDir: "{app}\plugins"; Flags: ignoreversion; Co
 
 Source: "python\*.py"; DestDir: "{app}\python"; Flags: ignoreversion; Components: langs\python
 
-Source: "plugins\hcpython3.dll"; DestDir: "{app}\plugins"; Flags: ignoreversion; Components: langs\python; Check: not IsWindows7
+Source: "plugins\hcpython3.dll"; DestDir: "{app}\plugins"; Flags: ignoreversion; Components: langs\python; Check: not NeedsLegacyPython
-Source: "plugins\hcpython38.dll"; DestDir: "{app}\plugins"; Flags: ignoreversion skipifsourcedoesntexist; Components: langs\python; Check: IsWindows7
+Source: "plugins\hcpython38.dll"; DestDir: "{app}\plugins"; Flags: ignoreversion skipifsourcedoesntexist; Components: langs\python; Check: NeedsLegacyPython
 Source: "_cffi_backend.cp3*.pyd"; DestDir: "{app}"; Flags: ignoreversion; Components: langs\python
 
 Source: "zoitechat.exe"; DestDir: "{app}"; Flags: ignoreversion; Components: libs
@@ -329,17 +329,19 @@ begin
 		Result := DirExists(ExpandConstant('{localappdata}') + '\enchant\myspell');
 end;
 
-function IsWindows7(): Boolean;
+// Python >= 3.9 dropped support for Windows versions before 10;
+// those systems get Python 3.8 and the matching plugin instead.
+function NeedsLegacyPython(): Boolean;
 var
 	Version: TWindowsVersion;
 begin
 	GetWindowsVersionEx(Version);
-	Result := Version.NTPlatform and (Version.Major = 6) and (Version.Minor = 1);
+	Result := Version.NTPlatform and (Version.Major < 10);
 end;
 
 function PythonURL(): String;
 begin
-	if IsWindows7() then
+	if NeedsLegacyPython() then
 		Result := 'https://www.python.org/ftp/python/3.8.10/python-3.8.10-amd64.exe'
 	else
 		Result := 'https://www.python.org/ftp/python/3.14.3/python-3.14.3-amd64.exe';
@@ -347,7 +349,7 @@ end;
 
 function PythonDLL(): String;
 begin
-	if IsWindows7() then
+	if NeedsLegacyPython() then
 		Result := 'python38.dll'
 	else
 		Result := 'python314.dll';

win32/zoitechat.props

@@ -8,7 +8,7 @@
 		<YourGendefPath>c:\gtk-build\gendef</YourGendefPath>
 		<YourPerlPath>c:\gtk-build\perl-5.42.0.1</YourPerlPath>
 		<YourPython3Path>c:\gtk-build\python-3.14</YourPython3Path>
-		<YourPython38Path>c:\gtk-build\python-3.8.10</YourPython38Path>
+		<YourPython38Path>c:\gtk-build\python-3.8</YourPython38Path>
 		<YourWinSparklePath>c:\gtk-build\WinSparkle</YourWinSparklePath>
 
 		<!-- YOU SHOULDN'T TOUCH ANYTHING BELOW -->