src/TortoiseShell/TortoiseStub.cpp

   1 // TortoiseGit - a Windows shell extension for easy version control
   2
   3 // Copyright (C) 2012-2013 - TortoiseGit
   4 // Copyright (C) 2007, 2009, 2013 - TortoiseSVN
   5
   6 // This program is free software; you can redistribute it and/or
   7 // modify it under the terms of the GNU General Public License
   8 // as published by the Free Software Foundation; either version 2
   9 // of the License, or (at your option) any later version.
  10
  11 // This program is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License
  17 // along with this program; if not, write to the Free Software Foundation,
  18 // 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 //
  20 #define _WIN32_WINNT 0x0400
  21 #include <Windows.h>
  22 #include <tchar.h>
  23 #include "Debug.h"
  24
  25 const HINSTANCE NIL = (HINSTANCE)((char*)(0)-1);
  26
  27 static HINSTANCE hInst = NULL;
  28
  29 static HINSTANCE hTortoiseGit = NULL;
  30 static LPFNGETCLASSOBJECT pDllGetClassObject = NULL;
  31 static LPFNCANUNLOADNOW pDllCanUnloadNow = NULL;
  32
  33 static BOOL DebugActive(void)
  34 {
  35         static const WCHAR TGitRootKey[]=_T("Software\\TortoiseGit");
  36         static const WCHAR ExplorerOnlyValue[]=_T("DebugShell");
  37
  38         DWORD bDebug = 0;
  39
  40         HKEY hKey = HKEY_CURRENT_USER;
  41         LONG Result = ERROR;
  42         DWORD Type = REG_DWORD;
  43         DWORD Len = sizeof(DWORD);
  44
  45         BOOL bDebugActive = FALSE;
  46
  47
  48         TRACE(_T("DebugActive() - Enter\n"));
  49
  50         if (IsDebuggerPresent())
  51         {
  52                 Result = RegOpenKeyEx(HKEY_LOCAL_MACHINE, TGitRootKey, 0, KEY_READ, &hKey);
  53                 if (Result == ERROR_SUCCESS)
  54                 {
  55                         Result = RegQueryValueEx(hKey, ExplorerOnlyValue, NULL, &Type, (BYTE *)&bDebug, &Len);
  56                         if ((Result == ERROR_SUCCESS) && (Type == REG_DWORD) && (Len == sizeof(DWORD)) && bDebug)
  57                         {
  58                                 TRACE(_T("DebugActive() - debug active\n"));
  59                                 bDebugActive = TRUE;
  60                         }
  61
  62                         RegCloseKey(hKey);
  63                 }
  64         }
  65
  66         TRACE(_T("WantRealVersion() - Exit\n"));
  67         return bDebugActive;
  68 }
  69
  70 /**
  71  * \ingroup TortoiseShell
  72  * Check whether to load the full TortoiseGit.dll or not.
  73  */
  74 static BOOL WantRealVersion(void)
  75 {
  76         static const WCHAR TGitRootKey[]=_T("Software\\TortoiseGit");
  77         static const WCHAR ExplorerOnlyValue[]=_T("LoadDllOnlyInExplorer");
  78
  79         static const WCHAR ExplorerEnvPath[]=_T("%SystemRoot%\\explorer.exe");
  80
  81
  82         DWORD bExplorerOnly = 0;
  83         WCHAR ModuleName[MAX_PATH] = {0};
  84         WCHAR ExplorerPath[MAX_PATH] = {0};
  85
  86         HKEY hKey = HKEY_CURRENT_USER;
  87         LONG Result = ERROR;
  88         DWORD Type = REG_DWORD;
  89         DWORD Len = sizeof(DWORD);
  90
  91         BOOL bWantReal = TRUE;
  92
  93         TRACE(_T("WantRealVersion() - Enter\n"));
  94
  95         Result = RegOpenKeyEx(HKEY_CURRENT_USER, TGitRootKey, 0, KEY_READ, &hKey);
  96         if (Result == ERROR_SUCCESS)
  97         {
  98                 Result = RegQueryValueEx(hKey, ExplorerOnlyValue, NULL, &Type, (BYTE *)&bExplorerOnly, &Len);
  99                 if ((Result == ERROR_SUCCESS) && (Type == REG_DWORD) && (Len == sizeof(DWORD)) && bExplorerOnly)
 100                 {
 101                         TRACE(_T("WantRealVersion() - Explorer Only\n"));
 102
 103                         // check if the current process is in fact the explorer
 104                         Len = GetModuleFileName(NULL, ModuleName, _countof(ModuleName));
 105                         if (Len)
 106                         {
 107                                 TRACE(_T("Process is %s\n"), ModuleName);
 108
 109                                 Len = ExpandEnvironmentStrings(ExplorerEnvPath, ExplorerPath, _countof(ExplorerPath));
 110                                 if (Len && (Len <= _countof(ExplorerPath)))
 111                                 {
 112                                         TRACE(_T("Explorer path is %s\n"), ExplorerPath);
 113                                         bWantReal = !lstrcmpi(ModuleName, ExplorerPath);
 114                                 }
 115
 116                                 // we also have to allow the verclsid.exe process - that process determines
 117                                 // first whether the shell is allowed to even use an extension.
 118                                 Len = lstrlen(ModuleName);
 119                                 if ((Len > 13)&&(lstrcmpi(&ModuleName[Len-13], _T("\\verclsid.exe")) == 0))
 120                                         bWantReal = TRUE;
 121                         }
 122                 }
 123
 124                 RegCloseKey(hKey);
 125         }
 126
 127         TRACE(_T("WantRealVersion() - Exit\n"));
 128         return bWantReal;
 129 }
 130
 131 static void LoadRealLibrary(void)
 132 {
 133         static const char GetClassObject[] = "DllGetClassObject";
 134         static const char CanUnloadNow[] = "DllCanUnloadNow";
 135
 136         WCHAR ModuleName[MAX_PATH] = {0};
 137         DWORD Len = 0;
 138         HINSTANCE hUseInst = hInst;
 139
 140         if (hTortoiseGit)
 141                 return;
 142
 143         if (!WantRealVersion())
 144         {
 145                 TRACE(_T("LoadRealLibrary() - Bypass\n"));
 146                 hTortoiseGit = NIL;
 147                 return;
 148         }
 149         // if HKCU\Software\TortoiseGit\DebugShell is set, load the dlls from the location of the current process
 150         // which is for our debug purposes an instance of usually TortoiseProc. That way we can force the load
 151         // of the debug dlls.
 152         if (DebugActive())
 153                 hUseInst = NULL;
 154         Len = GetModuleFileName(hUseInst, ModuleName, _countof(ModuleName));
 155         if (!Len)
 156         {
 157                 TRACE(_T("LoadRealLibrary() - Fail\n"));
 158                 hTortoiseGit = NIL;
 159                 return;
 160         }
 161
 162         // truncate the string at the last '\' char
 163         while(Len > 0)
 164         {
 165                 --Len;
 166                 if (ModuleName[Len] == '\\')
 167                 {
 168                         ModuleName[Len] = '\0';
 169                         break;
 170                 }
 171         }
 172         if (Len == 0)
 173         {
 174                 TRACE(_T("LoadRealLibrary() - Fail\n"));
 175                 hTortoiseGit = NIL;
 176                 return;
 177         }
 178 #ifdef _WIN64
 179         lstrcat(ModuleName, _T("\\TortoiseGit.dll"));
 180 #else
 181         lstrcat(ModuleName, _T("\\TortoiseGit32.dll"));
 182 #endif
 183         TRACE(_T("LoadRealLibrary() - Load %s\n"), ModuleName);
 184
 185         hTortoiseGit = LoadLibraryEx(ModuleName, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
 186         if (!hTortoiseGit)
 187         {
 188                 TRACE(_T("LoadRealLibrary() - Fail\n"));
 189                 hTortoiseGit = NIL;
 190                 return;
 191         }
 192
 193         TRACE(_T("LoadRealLibrary() - Success\n"));
 194         pDllGetClassObject = NULL;
 195         pDllCanUnloadNow = NULL;
 196         pDllGetClassObject = (LPFNGETCLASSOBJECT)GetProcAddress(hTortoiseGit, GetClassObject);
 197         if (pDllGetClassObject == NULL)
 198         {
 199                 TRACE(_T("LoadRealLibrary() - Fail\n"));
 200                 FreeLibrary(hTortoiseGit);
 201                 hTortoiseGit = NIL;
 202                 return;
 203         }
 204         pDllCanUnloadNow = (LPFNCANUNLOADNOW)GetProcAddress(hTortoiseGit, CanUnloadNow);
 205         if (pDllCanUnloadNow == NULL)
 206         {
 207                 TRACE(_T("LoadRealLibrary() - Fail\n"));
 208                 FreeLibrary(hTortoiseGit);
 209                 hTortoiseGit = NIL;
 210                 return;
 211         }
 212 }
 213
 214 static void UnloadRealLibrary(void)
 215 {
 216         if (!hTortoiseGit)
 217                 return;
 218
 219         if (hTortoiseGit != NIL)
 220                 FreeLibrary(hTortoiseGit);
 221
 222         hTortoiseGit = NULL;
 223         pDllGetClassObject = NULL;
 224         pDllCanUnloadNow = NULL;
 225 }
 226
 227 BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD Reason, LPVOID /*Reserved*/)
 228 {
 229 #ifdef _DEBUG
 230         // if no debugger is present, then don't load the dll.
 231         // this prevents other apps from loading the dll and locking
 232         // it.
 233
 234         BOOL bInShellTest = FALSE;
 235         TCHAR buf[MAX_PATH + 1];       // MAX_PATH ok, the test really is for debugging anyway.
 236         DWORD pathLength = GetModuleFileName(NULL, buf, MAX_PATH);
 237
 238         if (pathLength >= 14)
 239         {
 240                 if ((lstrcmpi(&buf[pathLength-14], _T("\\ShellTest.exe"))) == 0)
 241                 {
 242                         bInShellTest = TRUE;
 243                 }
 244                 if ((_tcsicmp(&buf[pathLength-13], _T("\\verclsid.exe"))) == 0)
 245                 {
 246                         bInShellTest = TRUE;
 247                 }
 248         }
 249
 250         if (!IsDebuggerPresent() && !bInShellTest)
 251         {
 252                 TRACE(_T("In debug load preventer\n"));
 253                 return FALSE;
 254         }
 255 #endif
 256
 257         switch(Reason)
 258         {
 259         case DLL_PROCESS_ATTACH:
 260                 hInst = hInstance;
 261                 break;
 262
 263         /*case DLL_THREAD_ATTACH:
 264                 break;
 265
 266         case DLL_THREAD_DETACH:
 267                 break;
 268
 269         case DLL_PROCESS_DETACH:
 270                 break;*/
 271         }
 272
 273         return TRUE;
 274 }
 275
 276 STDAPI DllGetClassObject(REFCLSID rclsid, REFIID riid, LPVOID *ppv)
 277 {
 278         TRACE(_T("DllGetClassObject() - Enter\n"));
 279
 280         LoadRealLibrary();
 281         if (!pDllGetClassObject)
 282         {
 283                 if (ppv)
 284                         *ppv = NULL;
 285
 286                 TRACE(_T("DllGetClassObject() - Bypass\n"));
 287                 return CLASS_E_CLASSNOTAVAILABLE;
 288         }
 289
 290         TRACE(_T("DllGetClassObject() - Forward\n"));
 291         return pDllGetClassObject(rclsid, riid, ppv);
 292 }
 293
 294 STDAPI DllCanUnloadNow(void)
 295 {
 296         TRACE(_T("DllCanUnloadNow() - Enter\n"));
 297
 298         if (pDllCanUnloadNow)
 299         {
 300                 TRACE(_T("DllCanUnloadNow() - Forward\n"));
 301                 HRESULT Result = pDllCanUnloadNow();
 302                 if (Result != S_OK)
 303                         return Result;
 304         }
 305
 306         TRACE(_T("DllCanUnloadNow() - Unload\n"));
 307         UnloadRealLibrary();
 308         return S_OK;
 309 }
 310