1 2 /* Support for dynamic loading of extension modules */ 3 4 #include "Python.h" 5 6 #ifdef HAVE_DIRECT_H 7 #include <direct.h> 8 #endif 9 #include <ctype.h> 10 11 #include "importdl.h" 12 #include <windows.h> 13 14 // "activation context" magic - see dl_nt.c... 15 extern ULONG_PTR _Py_ActivateActCtx(); 16 void _Py_DeactivateActCtx(ULONG_PTR cookie); 17 18 const struct filedescr _PyImport_DynLoadFiletab[] = { 19 #ifdef _DEBUG 20 {"_d.pyd", "rb", C_EXTENSION}, 21 #else 22 {".pyd", "rb", C_EXTENSION}, 23 #endif 24 {0, 0} 25 }; 26 27 28 /* Case insensitive string compare, to avoid any dependencies on particular 29 C RTL implementations */ 30 31 static int strcasecmp (char *string1, char *string2) 32 { 33 int first, second; 34 35 do { 36 first = tolower(*string1); 37 second = tolower(*string2); 38 string1++; 39 string2++; 40 } while (first && first == second); 41 42 return (first - second); 43 } 44 45 46 /* Function to return the name of the "python" DLL that the supplied module 47 directly imports. Looks through the list of imported modules and 48 returns the first entry that starts with "python" (case sensitive) and 49 is followed by nothing but numbers until the separator (period). 50 51 Returns a pointer to the import name, or NULL if no matching name was 52 located. 53 54 This function parses through the PE header for the module as loaded in 55 memory by the system loader. The PE header is accessed as documented by 56 Microsoft in the MSDN PE and COFF specification (2/99), and handles 57 both PE32 and PE32+. It only worries about the direct import table and 58 not the delay load import table since it's unlikely an extension is 59 going to be delay loading Python (after all, it's already loaded). 60 61 If any magic values are not found (e.g., the PE header or optional 62 header magic), then this function simply returns NULL. */ 63 64 #define DWORD_AT(mem) (*(DWORD *)(mem)) 65 #define WORD_AT(mem) (*(WORD *)(mem)) 66 67 static char *GetPythonImport (HINSTANCE hModule) 68 { 69 unsigned char *dllbase, *import_data, *import_name; 70 DWORD pe_offset, opt_offset; 71 WORD opt_magic; 72 int num_dict_off, import_off; 73 74 /* Safety check input */ 75 if (hModule == NULL) { 76 return NULL; 77 } 78 79 /* Module instance is also the base load address. First portion of 80 memory is the MS-DOS loader, which holds the offset to the PE 81 header (from the load base) at 0x3C */ 82 dllbase = (unsigned char *)hModule; 83 pe_offset = DWORD_AT(dllbase + 0x3C); 84 85 /* The PE signature must be "PE\0\0" */ 86 if (memcmp(dllbase+pe_offset,"PE\0\0",4)) { 87 return NULL; 88 } 89 90 /* Following the PE signature is the standard COFF header (20 91 bytes) and then the optional header. The optional header starts 92 with a magic value of 0x10B for PE32 or 0x20B for PE32+ (PE32+ 93 uses 64-bits for some fields). It might also be 0x107 for a ROM 94 image, but we don't process that here. 95 96 The optional header ends with a data dictionary that directly 97 points to certain types of data, among them the import entries 98 (in the second table entry). Based on the header type, we 99 determine offsets for the data dictionary count and the entry 100 within the dictionary pointing to the imports. */ 101 102 opt_offset = pe_offset + 4 + 20; 103 opt_magic = WORD_AT(dllbase+opt_offset); 104 if (opt_magic == 0x10B) { 105 /* PE32 */ 106 num_dict_off = 92; 107 import_off = 104; 108 } else if (opt_magic == 0x20B) { 109 /* PE32+ */ 110 num_dict_off = 108; 111 import_off = 120; 112 } else { 113 /* Unsupported */ 114 return NULL; 115 } 116 117 /* Now if an import table exists, offset to it and walk the list of 118 imports. The import table is an array (ending when an entry has 119 empty values) of structures (20 bytes each), which contains (at 120 offset 12) a relative address (to the module base) at which a 121 string constant holding the import name is located. */ 122 123 if (DWORD_AT(dllbase + opt_offset + num_dict_off) >= 2) { 124 /* We have at least 2 tables - the import table is the second 125 one. But still it may be that the table size is zero */ 126 if (0 == DWORD_AT(dllbase + opt_offset + import_off + sizeof(DWORD))) 127 return NULL; 128 import_data = dllbase + DWORD_AT(dllbase + 129 opt_offset + 130 import_off); 131 while (DWORD_AT(import_data)) { 132 import_name = dllbase + DWORD_AT(import_data+12); 133 if (strlen(import_name) >= 6 && 134 !strncmp(import_name,"python",6)) { 135 char *pch; 136 137 /* Ensure python prefix is followed only 138 by numbers to the end of the basename */ 139 pch = import_name + 6; 140 #ifdef _DEBUG 141 while (*pch && pch[0] != '_' && pch[1] != 'd' && pch[2] != '.') { 142 #else 143 while (*pch && *pch != '.') { 144 #endif 145 if (*pch >= '0' && *pch <= '9') { 146 pch++; 147 } else { 148 pch = NULL; 149 break; 150 } 151 } 152 153 if (pch) { 154 /* Found it - return the name */ 155 return import_name; 156 } 157 } 158 import_data += 20; 159 } 160 } 161 162 return NULL; 163 } 164 165 166 dl_funcptr _PyImport_GetDynLoadFunc(const char *fqname, const char *shortname, 167 const char *pathname, FILE *fp) 168 { 169 dl_funcptr p; 170 char funcname[258], *import_python; 171 172 PyOS_snprintf(funcname, sizeof(funcname), "init%.200s", shortname); 173 174 { 175 HINSTANCE hDLL = NULL; 176 char pathbuf[260]; 177 LPTSTR dummy; 178 unsigned int old_mode; 179 ULONG_PTR cookie = 0; 180 /* We use LoadLibraryEx so Windows looks for dependent DLLs 181 in directory of pathname first. However, Windows95 182 can sometimes not work correctly unless the absolute 183 path is used. If GetFullPathName() fails, the LoadLibrary 184 will certainly fail too, so use its error code */ 185 186 /* Don't display a message box when Python can't load a DLL */ 187 old_mode = SetErrorMode(SEM_FAILCRITICALERRORS); 188 189 if (GetFullPathName(pathname, 190 sizeof(pathbuf), 191 pathbuf, 192 &dummy)) { 193 ULONG_PTR cookie = _Py_ActivateActCtx(); 194 /* XXX This call doesn't exist in Windows CE */ 195 hDLL = LoadLibraryEx(pathname, NULL, 196 LOAD_WITH_ALTERED_SEARCH_PATH); 197 _Py_DeactivateActCtx(cookie); 198 } 199 200 /* restore old error mode settings */ 201 SetErrorMode(old_mode); 202 203 if (hDLL==NULL){ 204 char errBuf[256]; 205 unsigned int errorCode; 206 207 /* Get an error string from Win32 error code */ 208 char theInfo[256]; /* Pointer to error text 209 from system */ 210 int theLength; /* Length of error text */ 211 212 errorCode = GetLastError(); 213 214 theLength = FormatMessage( 215 FORMAT_MESSAGE_FROM_SYSTEM | 216 FORMAT_MESSAGE_IGNORE_INSERTS, /* flags */ 217 NULL, /* message source */ 218 errorCode, /* the message (error) ID */ 219 0, /* default language environment */ 220 (LPTSTR) theInfo, /* the buffer */ 221 sizeof(theInfo), /* the buffer size */ 222 NULL); /* no additional format args. */ 223 224 /* Problem: could not get the error message. 225 This should not happen if called correctly. */ 226 if (theLength == 0) { 227 PyOS_snprintf(errBuf, sizeof(errBuf), 228 "DLL load failed with error code %d", 229 errorCode); 230 } else { 231 size_t len; 232 /* For some reason a \r\n 233 is appended to the text */ 234 if (theLength >= 2 && 235 theInfo[theLength-2] == '\r' && 236 theInfo[theLength-1] == '\n') { 237 theLength -= 2; 238 theInfo[theLength] = '\0'; 239 } 240 strcpy(errBuf, "DLL load failed: "); 241 len = strlen(errBuf); 242 strncpy(errBuf+len, theInfo, 243 sizeof(errBuf)-len); 244 errBuf[sizeof(errBuf)-1] = '\0'; 245 } 246 PyErr_SetString(PyExc_ImportError, errBuf); 247 return NULL; 248 } else { 249 char buffer[256]; 250 251 #ifdef _DEBUG 252 PyOS_snprintf(buffer, sizeof(buffer), "python%d%d_d.dll", 253 #else 254 PyOS_snprintf(buffer, sizeof(buffer), "python%d%d.dll", 255 #endif 256 PY_MAJOR_VERSION,PY_MINOR_VERSION); 257 import_python = GetPythonImport(hDLL); 258 259 if (import_python && 260 strcasecmp(buffer,import_python)) { 261 PyOS_snprintf(buffer, sizeof(buffer), 262 "Module use of %.150s conflicts " 263 "with this version of Python.", 264 import_python); 265 PyErr_SetString(PyExc_ImportError,buffer); 266 FreeLibrary(hDLL); 267 return NULL; 268 } 269 } 270 p = GetProcAddress(hDLL, funcname); 271 } 272 273 return p; 274 } 275
