dll.c

   1 #include <shlobj.h>
   2 #include <stdio.h>
   3 #include "dll.h"
   4 #include "menuengine.h"
   5 #include "ext.h"
   6 #include "factory.h"
   7 #include "systeminfo.h"
   8 #include "registry.h"
   9
  10 /*
  11  * The following is just the necessary infrastructure for having a .dll
  12  * which can be registered as a COM object.
  13  */
  14 static HINSTANCE hInst;
  15
  16 HRESULT PASCAL DllGetClassObject(REFCLSID obj_guid, REFIID factory_guid,
  17                 void **factory_handle)
  18 {
  19         if (IsEqualCLSID(obj_guid, &CLSID_git_shell_ext) ||
  20                         IsEqualCLSID(obj_guid, &CLSID_git_menu))
  21                 return class_factory_query_interface(&factory,
  22                                 factory_guid, factory_handle);
  23
  24         *factory_handle = 0;
  25         return CLASS_E_CLASSNOTAVAILABLE;
  26 }
  27
  28 HRESULT PASCAL DllCanUnloadNow(void)
  29 {
  30    return (object_count || lock_count) ? S_FALSE : S_OK;
  31 }
  32
  33 BOOL WINAPI DllMain(HINSTANCE instance, DWORD reason, LPVOID reserved)
  34 {
  35         hInst = instance;
  36
  37         if (reason == DLL_PROCESS_ATTACH) {
  38                 object_count = lock_count = 0;
  39                 DisableThreadLibraryCalls(instance);
  40         }
  41
  42         return 1;
  43 }
  44
  45 /* replaces a substring pattern with a string replacement within a string
  46    the replacement occurs in-place, hence string must be large enough to
  47    hold the result
  48
  49    the function does not handle recursive replacements, e.g.
  50      strreplace ("foo", "bar", "another bar");
  51
  52    always returns *string
  53 */
  54 static char *strreplace(char *string, const size_t size,
  55                         const char *pattern, const char *replacement)
  56 {
  57         size_t len = strlen(string);
  58         const size_t pattern_len = strlen(pattern);
  59         const size_t replace_len = strlen(replacement);
  60
  61         char *found = strstr(string, pattern);
  62
  63         while (found) {
  64                 /* if the new len is greater than size, bail out */
  65                 if (len + replace_len - pattern_len >= size)
  66                         return string;
  67
  68                 if (pattern_len != replace_len)
  69                         memmove(found + replace_len,
  70                                 found + pattern_len,
  71                                 len - (found - string) - pattern_len + 1);
  72                 memcpy(found, replacement, replace_len);
  73                 len += replace_len - pattern_len;
  74
  75                 found = strstr(string, pattern);
  76         }
  77
  78         return string;
  79 }
  80
  81 /*
  82  * The following is the data for our minimal regedit engine,
  83  * required for registration/unregistration of the extension
  84  */
  85 #define CLASS_CHEETAH CLASSES_ROOT "CLSID\\@@CLSID@@"
  86 #define CONTEXTMENUHANDLER "shellex\\ContextMenuHandlers\\@@PROGRAM_NAME@@"
  87
  88 static const char *get_module_filename() {
  89         static char module_filename[MAX_PATH] = { '\0' };
  90
  91         if (!*module_filename) {
  92                 DWORD module_size;
  93
  94                 module_size = GetModuleFileName(hInst,
  95                                 module_filename, MAX_PATH);
  96                 if (0 == module_size)
  97                         return NULL;
  98         }
  99
 100         return module_filename;
 101 }
 102
 103 /* as per "How to: Convert Between System::Guid and _GUID" */
 104 static const char *get_class_id()
 105 {
 106         static char class_id[MAX_REGISTRY_PATH] = { '\0' };
 107
 108         if (!*class_id) {
 109                 GUID guid = CLSID_git_shell_ext;
 110                 sprintf(class_id,
 111                         "{%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x}",
 112                         guid.Data1, guid.Data2, guid.Data3,
 113                         guid.Data4[0], guid.Data4[1], guid.Data4[2],
 114                         guid.Data4[3], guid.Data4[4], guid.Data4[5],
 115                         guid.Data4[6], guid.Data4[7]);
 116         }
 117
 118         return class_id;
 119 }
 120
 121 /*
 122  * Tries to find msysGit in the following order:
 123  * .. and ../.. (relative to the module)
 124  * %PATH%
 125  * as qgit (via InstallLocation of Git)
 126  SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Git_is1\InstallLocation
 127  */
 128 static const reg_value registry_info[] = {
 129         { CURRENT_WINDOWS APPROVED_EXT, "@@CLSID@@", "@@PROGRAM_NAME@@" },
 130         { CURRENT_WINDOWS APPROVED_EXT "\\@@CLSID@@",
 131                 NULL, NULL },
 132         { CURRENT_WINDOWS APPROVED_EXT "\\@@CLSID@@",
 133                 NULL,"@@PROGRAM_NAME@@" },
 134         { CLASS_CHEETAH, NULL, NULL },
 135         { CLASS_CHEETAH, NULL, "@@PROGRAM_NAME@@" },
 136         { CLASS_CHEETAH "\\InProcServer32", NULL, NULL },
 137         { CLASS_CHEETAH "\\InProcServer32", NULL, "@@PROGRAM_PATH@@"},
 138         { CLASS_CHEETAH "\\InProcServer32", "ThreadingModel", "Apartment" },
 139         { CLASSES_ROOT "*\\" CONTEXTMENUHANDLER, NULL, NULL },
 140         { CLASSES_ROOT "*\\" CONTEXTMENUHANDLER, NULL, "@@CLSID@@" },
 141         { CLASSES_ROOT "Directory\\" CONTEXTMENUHANDLER, NULL, NULL },
 142         { CLASSES_ROOT "Directory\\" CONTEXTMENUHANDLER, NULL, "@@CLSID@@" },
 143         { CLASSES_ROOT "Directory\\Background\\" CONTEXTMENUHANDLER,
 144                 NULL, NULL },
 145         { CLASSES_ROOT "Directory\\Background\\" CONTEXTMENUHANDLER,
 146                 NULL, "@@CLSID@@" },
 147         { CLASSES_ROOT "Drive\\" CONTEXTMENUHANDLER, NULL, NULL },
 148         { CLASSES_ROOT "Drive\\" CONTEXTMENUHANDLER, NULL, "@@CLSID@@"},
 149         { CLASSES_ROOT "Folder\\" CONTEXTMENUHANDLER, NULL, NULL },
 150         { CLASSES_ROOT "Folder\\" CONTEXTMENUHANDLER, NULL, "@@CLSID@@" },
 151         { CLASSES_ROOT "InternetShortcut\\" CONTEXTMENUHANDLER,
 152                 NULL, NULL },
 153         { CLASSES_ROOT "InternetShortcut\\" CONTEXTMENUHANDLER,
 154                 NULL, "@@CLSID@@" },
 155         { GIT_CHEETAH_REG_PATH, NULL, NULL },
 156         { GIT_CHEETAH_REG_PATH,
 157                 GIT_CHEETAH_REG_PATHTOMSYS, "@@MSYSGIT_PATH@@" },
 158         { NULL, NULL, NULL }
 159 };
 160
 161 static const reg_value debug_info[] = {
 162         { CURRENT_WINDOWS "Explorer", "DesktopProcess", "1" },
 163         { CURRENT_WINDOWS "Explorer\\AlwaysUnloadDll", NULL, NULL },
 164         { CURRENT_WINDOWS "Explorer\\Advanced", "SeparateProcess", "1" },
 165         { NULL, NULL, NULL }
 166 };
 167
 168 static char msysgit[MAX_PATH] = { '\0' };
 169
 170 static BOOL find_msysgit_in_path()
 171 {
 172         char *file; /* file part of the path to git.exe */
 173         DWORD dwFound; /* length of path to git.exe */
 174
 175         dwFound = SearchPath(NULL, "git.exe", NULL, MAX_PATH, msysgit, &file);
 176         /* if git is not in the PATH or its path is too long */
 177         if (0 == dwFound ||
 178                 dwFound > MAX_PATH)
 179                 return FALSE;
 180
 181         /*
 182          * git.exe is in "\bin\" from what we really need
 183          * the minimal case we can handle is c:\bin\git.exe
 184          * otherwise declare failure
 185          */
 186         if (file < msysgit + 7)
 187                 return FALSE;
 188         if (strnicmp(file - 5, "\\bin\\", 5))
 189                 return FALSE;
 190         file[-5] = '\0';
 191
 192         return TRUE;
 193 }
 194
 195 static BOOL find_msysgit_relative(const char *path)
 196 {
 197         char *c;
 198
 199         strcpy(msysgit, get_module_filename());
 200         c = strrchr(msysgit, '\\');
 201         c[1] = '\0';
 202         strcat(msysgit, path);
 203         strcat(msysgit, "\\bin\\git.exe");
 204         if (INVALID_FILE_ATTRIBUTES == GetFileAttributes(msysgit)) {
 205                 msysgit[0] = '\0'; /* restore the original result */
 206                 return FALSE;
 207         }
 208
 209         c[1] = '\0';
 210         strcat(msysgit, path);
 211         return TRUE;
 212 }
 213
 214 static BOOL find_msysgit_uninstall(HKEY root)
 215 {
 216         HKEY key;
 217         HRESULT result;
 218         DWORD valuelen = MAX_PATH;
 219
 220         result = RegOpenKeyEx(root,
 221                         CURRENT_WINDOWS "\\Uninstall\\Git_is1",
 222                         0, KEY_READ, &key);
 223         if (ERROR_SUCCESS != result)
 224                 return FALSE;
 225
 226         result = RegQueryValue(key, "InstallLocation",
 227                         (LPBYTE)msysgit, &valuelen);
 228         return ERROR_SUCCESS == result;
 229 }
 230
 231 static HKEY setup_root;
 232
 233 static const char *find_msysgit()
 234 {
 235         if ('\0' == msysgit[0]) {
 236                 if (find_msysgit_relative(".."))
 237                         return msysgit;
 238
 239                 if (find_msysgit_relative("..\\.."))
 240                         return msysgit;
 241
 242                 if (find_msysgit_in_path())
 243                         return msysgit;
 244
 245                 if (setup_root)
 246                         find_msysgit_uninstall(setup_root);
 247         }
 248
 249         return msysgit;
 250 }
 251
 252 /*
 253  * required by registry.c
 254  * supports @@PROGRAM_NAME@@, @@PROGRAM_PATH@@, @@CLSID@@ patterns
 255  */
 256 char *get_registry_path(const char *src, char dst[MAX_REGISTRY_PATH])
 257 {
 258         if (NULL == src)
 259                 return NULL;
 260
 261         strcpy(dst, src);
 262         strreplace(dst, MAX_REGISTRY_PATH,
 263                         "@@PROGRAM_NAME@@", program_name);
 264         strreplace(dst, MAX_REGISTRY_PATH,
 265                         "@@PROGRAM_PATH@@", get_module_filename());
 266         strreplace(dst, MAX_REGISTRY_PATH,
 267                         "@@CLSID@@", get_class_id());
 268         strreplace(dst, MAX_REGISTRY_PATH,
 269                         "@@MSYSGIT_PATH@@", find_msysgit());
 270
 271         return dst;
 272 }
 273
 274 HRESULT PASCAL DllRegisterServer(void)
 275 {
 276         setup_root = HKEY_CURRENT_USER;
 277         return create_reg_entries (setup_root, registry_info);
 278 }
 279
 280 HRESULT PASCAL DllUnregisterServer(void)
 281 {
 282         setup_root = HKEY_CURRENT_USER;
 283         return delete_reg_entries(setup_root, registry_info);
 284 }
 285
 286 /* provide means to create/delete keys:
 287    - described in Debugging with The Shell;
 288    - machine-wide registration and debugging info
 289
 290    possible combinations of regsvr32 command line options:
 291              -n  (absent)               (present)
 292    -i:
 293    (absent)      user reg               (invalid)
 294    debug         user reg+debug         user debug
 295    machine       user+machine reg       machine reg
 296    machinedebug  user+machine reg+debug machine reg+debug
 297
 298    Obviously missing option is "machine debug". To accomplish:
 299    - execute "regsvr32 -n -i:machinedebug" and then
 300    - regsvr32 -u -n -i:machine
 301 */
 302 HRESULT PASCAL DllInstall(BOOL bInstall, LPCWSTR pszCmdLine)
 303 {
 304         BOOL bDebug = NULL != wcsstr(pszCmdLine, L"debug");
 305         HRESULT result = ERROR_SUCCESS;
 306
 307         setup_root = wcsstr(pszCmdLine, L"machine") ?
 308                         HKEY_LOCAL_MACHINE : HKEY_CURRENT_USER;
 309
 310         if (bInstall) {
 311                 if (bDebug)
 312                         result = create_reg_entries(setup_root, debug_info);
 313
 314                 /* for user-only registration, use DllRegister */
 315                 if (ERROR_SUCCESS == result &&
 316                     HKEY_LOCAL_MACHINE == setup_root)
 317                         result = create_reg_entries(setup_root,
 318                                         registry_info);
 319         } else { /* uninstall */
 320                 if (bDebug)
 321                         result = delete_reg_entries(setup_root, debug_info);
 322
 323                 /* for user-only unregistration, use DllUnregister */
 324                 if (ERROR_SUCCESS == result &&
 325                     HKEY_LOCAL_MACHINE == setup_root)
 326                         result = delete_reg_entries(setup_root,
 327                                         registry_info);
 328         }
 329
 330         return result;
 331 }