cpython/Python/dynload_win.c at 2.7 · python-emscripten/cpython · GitHub

Repository navigation

History

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

/* Support for dynamic loading of extension modules */

#include "Python.h"

#ifdef HAVE_DIRECT_H

#include <direct.h>

#endif

#include <ctype.h>

#include "importdl.h"

#include <windows.h>

// "activation context" magic - see dl_nt.c...

extern ULONG_PTR _Py_ActivateActCtx();

void _Py_DeactivateActCtx(ULONG_PTR cookie);

const struct filedescr _PyImport_DynLoadFiletab[] = {

#ifdef _DEBUG

{"_d.pyd", "rb", C_EXTENSION},

#else

{".pyd", "rb", C_EXTENSION},

#endif

{0, 0}

};

/* Case insensitive string compare, to avoid any dependencies on particular

C RTL implementations */

static int strcasecmp (char *string1, char *string2)

{

int first, second;

do {

first = tolower(*string1);

second = tolower(*string2);

string1++;

string2++;

} while (first && first == second);

return (first - second);

}

/* Function to return the name of the "python" DLL that the supplied module

directly imports. Looks through the list of imported modules and

returns the first entry that starts with "python" (case sensitive) and

is followed by nothing but numbers until the separator (period).

Returns a pointer to the import name, or NULL if no matching name was

located.

This function parses through the PE header for the module as loaded in

memory by the system loader. The PE header is accessed as documented by

Microsoft in the MSDN PE and COFF specification (2/99), and handles

both PE32 and PE32+. It only worries about the direct import table and

not the delay load import table since it's unlikely an extension is

going to be delay loading Python (after all, it's already loaded).

If any magic values are not found (e.g., the PE header or optional

header magic), then this function simply returns NULL. */

#define DWORD_AT(mem) (*(DWORD *)(mem))

#define WORD_AT(mem) (*(WORD *)(mem))

static char *GetPythonImport (HINSTANCE hModule)

{

unsigned char *dllbase, *import_data, *import_name;

DWORD pe_offset, opt_offset;

WORD opt_magic;

int num_dict_off, import_off;

/* Safety check input */

if (hModule == NULL) {

return NULL;

}

/* Module instance is also the base load address. First portion of

memory is the MS-DOS loader, which holds the offset to the PE

header (from the load base) at 0x3C */

dllbase = (unsigned char *)hModule;

pe_offset = DWORD_AT(dllbase + 0x3C);

/* The PE signature must be "PE\0\0" */

if (memcmp(dllbase+pe_offset,"PE\0\0",4)) {

return NULL;

}

/* Following the PE signature is the standard COFF header (20

bytes) and then the optional header. The optional header starts

with a magic value of 0x10B for PE32 or 0x20B for PE32+ (PE32+

uses 64-bits for some fields). It might also be 0x107 for a ROM

image, but we don't process that here.

The optional header ends with a data dictionary that directly

points to certain types of data, among them the import entries

(in the second table entry). Based on the header type, we

determine offsets for the data dictionary count and the entry

within the dictionary pointing to the imports. */

opt_offset = pe_offset + 4 + 20;

opt_magic = WORD_AT(dllbase+opt_offset);

if (opt_magic == 0x10B) {

/* PE32 */

num_dict_off = 92;

import_off = 104;

} else if (opt_magic == 0x20B) {

/* PE32+ */

num_dict_off = 108;

import_off = 120;

} else {

/* Unsupported */

return NULL;

}

/* Now if an import table exists, offset to it and walk the list of

imports. The import table is an array (ending when an entry has

empty values) of structures (20 bytes each), which contains (at

offset 12) a relative address (to the module base) at which a

string constant holding the import name is located. */

if (DWORD_AT(dllbase + opt_offset + num_dict_off) >= 2) {

/* We have at least 2 tables - the import table is the second

one. But still it may be that the table size is zero */

if (0 == DWORD_AT(dllbase + opt_offset + import_off + sizeof(DWORD)))

return NULL;

import_data = dllbase + DWORD_AT(dllbase +

opt_offset +

import_off);

while (DWORD_AT(import_data)) {

import_name = dllbase + DWORD_AT(import_data+12);

if (strlen(import_name) >= 6 &&

!strncmp(import_name,"python",6)) {

char *pch;

/* Ensure python prefix is followed only

by numbers to the end of the basename */

pch = import_name + 6;

#ifdef _DEBUG

while (*pch && pch[0] != '_' && pch[1] != 'd' && pch[2] != '.') {

#else

while (*pch && *pch != '.') {

#endif

if (*pch >= '0' && *pch <= '9') {

pch++;

} else {

pch = NULL;

break;

}

if (pch) {

/* Found it - return the name */

return import_name;

}

import_data += 20;

}

return NULL;

}

dl_funcptr _PyImport_GetDynLoadFunc(const char *fqname, const char *shortname,

const char *pathname, FILE *fp)

{

dl_funcptr p;

char funcname[258], *import_python;

PyOS_snprintf(funcname, sizeof(funcname), "init%.200s", shortname);

{

HINSTANCE hDLL = NULL;

char pathbuf[260];

LPTSTR dummy;

unsigned int old_mode;

ULONG_PTR cookie = 0;

/* We use LoadLibraryEx so Windows looks for dependent DLLs

in directory of pathname first. However, Windows95

can sometimes not work correctly unless the absolute

path is used. If GetFullPathName() fails, the LoadLibrary

will certainly fail too, so use its error code */

/* Don't display a message box when Python can't load a DLL */

old_mode = SetErrorMode(SEM_FAILCRITICALERRORS);

if (GetFullPathName(pathname,

sizeof(pathbuf),

pathbuf,

&dummy)) {

ULONG_PTR cookie = _Py_ActivateActCtx();

/* XXX This call doesn't exist in Windows CE */

hDLL = LoadLibraryEx(pathname, NULL,

LOAD_WITH_ALTERED_SEARCH_PATH);

_Py_DeactivateActCtx(cookie);

}

/* restore old error mode settings */

SetErrorMode(old_mode);

if (hDLL==NULL){

char errBuf[256];

unsigned int errorCode;

/* Get an error string from Win32 error code */

char theInfo[256]; /* Pointer to error text

from system */

int theLength; /* Length of error text */

errorCode = GetLastError();

theLength = FormatMessage(

FORMAT_MESSAGE_FROM_SYSTEM |

FORMAT_MESSAGE_IGNORE_INSERTS, /* flags */

NULL, /* message source */

errorCode, /* the message (error) ID */

0, /* default language environment */

(LPTSTR) theInfo, /* the buffer */

sizeof(theInfo), /* the buffer size */

NULL); /* no additional format args. */

/* Problem: could not get the error message.

This should not happen if called correctly. */

if (theLength == 0) {

PyOS_snprintf(errBuf, sizeof(errBuf),

"DLL load failed with error code %d",

errorCode);

} else {

size_t len;

/* For some reason a \r\n

is appended to the text */

if (theLength >= 2 &&

theInfo[theLength-2] == '\r' &&

theInfo[theLength-1] == '\n') {

theLength -= 2;

theInfo[theLength] = '\0';

}

strcpy(errBuf, "DLL load failed: ");

len = strlen(errBuf);

strncpy(errBuf+len, theInfo,

sizeof(errBuf)-len);

errBuf[sizeof(errBuf)-1] = '\0';

}

PyErr_SetString(PyExc_ImportError, errBuf);

return NULL;

} else {

char buffer[256];

#ifdef _DEBUG

PyOS_snprintf(buffer, sizeof(buffer), "python%d%d_d.dll",

#else

PyOS_snprintf(buffer, sizeof(buffer), "python%d%d.dll",

#endif

PY_MAJOR_VERSION,PY_MINOR_VERSION);

import_python = GetPythonImport(hDLL);

if (import_python &&

strcasecmp(buffer,import_python)) {

PyOS_snprintf(buffer, sizeof(buffer),

"Module use of %.150s conflicts "

"with this version of Python.",

import_python);

PyErr_SetString(PyExc_ImportError,buffer);

FreeLibrary(hDLL);

return NULL;

}

p = GetProcAddress(hDLL, funcname);

}

return p;

}

cpython/Python/dynload_win.c at 2.7 · python-emscripten/cpython · GitHub

Repository navigation

Expand file tree

Breadcrumbs

dynload_win.c

Latest commit

History

Breadcrumbs

dynload_win.c

File metadata and controls