dll.c

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