1
2 /* Support for dynamic loading of extension modules */
3
4 #include "Python.h"
5
6 /* ./configure sets HAVE_DYNAMIC_LOADING if dynamic loading of modules is
7 supported on this platform. configure will then compile and link in one
8 of the dynload_*.c files, as appropriate. We will call a function in
9 those modules to get a function pointer to the module's init function.
10 */
11 #ifdef HAVE_DYNAMIC_LOADING
12
13 #include "importdl.h"
14
15 #ifdef MS_WINDOWS
16 extern dl_funcptr _PyImport_FindSharedFuncptrWindows(const char *prefix,
17 const char *shortname,
18 PyObject *pathname,
19 FILE *fp);
20 #else
21 extern dl_funcptr _PyImport_FindSharedFuncptr(const char *prefix,
22 const char *shortname,
23 const char *pathname, FILE *fp);
24 #endif
25
26 static const char * const ascii_only_prefix = "PyInit";
27 static const char * const nonascii_prefix = "PyInitU";
28
29 /* Get the variable part of a module's export symbol name.
30 * Returns a bytes instance. For non-ASCII-named modules, the name is
31 * encoded as per PEP 489.
32 * The hook_prefix pointer is set to either ascii_only_prefix or
33 * nonascii_prefix, as appropriate.
34 */
35 static PyObject *
get_encoded_name(PyObject * name,const char ** hook_prefix)36 get_encoded_name(PyObject *name, const char **hook_prefix) {
37 PyObject *tmp;
38 PyObject *encoded = NULL;
39 PyObject *modname = NULL;
40 Py_ssize_t name_len, lastdot;
41 _Py_IDENTIFIER(replace);
42
43 /* Get the short name (substring after last dot) */
44 name_len = PyUnicode_GetLength(name);
45 lastdot = PyUnicode_FindChar(name, '.', 0, name_len, -1);
46 if (lastdot < -1) {
47 return NULL;
48 } else if (lastdot >= 0) {
49 tmp = PyUnicode_Substring(name, lastdot + 1, name_len);
50 if (tmp == NULL)
51 return NULL;
52 name = tmp;
53 /* "name" now holds a new reference to the substring */
54 } else {
55 Py_INCREF(name);
56 }
57
58 /* Encode to ASCII or Punycode, as needed */
59 encoded = PyUnicode_AsEncodedString(name, "ascii", NULL);
60 if (encoded != NULL) {
61 *hook_prefix = ascii_only_prefix;
62 } else {
63 if (PyErr_ExceptionMatches(PyExc_UnicodeEncodeError)) {
64 PyErr_Clear();
65 encoded = PyUnicode_AsEncodedString(name, "punycode", NULL);
66 if (encoded == NULL) {
67 goto error;
68 }
69 *hook_prefix = nonascii_prefix;
70 } else {
71 goto error;
72 }
73 }
74
75 /* Replace '-' by '_' */
76 modname = _PyObject_CallMethodId(encoded, &PyId_replace, "cc", '-', '_');
77 if (modname == NULL)
78 goto error;
79
80 Py_DECREF(name);
81 Py_DECREF(encoded);
82 return modname;
83 error:
84 Py_DECREF(name);
85 Py_XDECREF(encoded);
86 return NULL;
87 }
88
89 PyObject *
_PyImport_LoadDynamicModuleWithSpec(PyObject * spec,FILE * fp)90 _PyImport_LoadDynamicModuleWithSpec(PyObject *spec, FILE *fp)
91 {
92 #ifndef MS_WINDOWS
93 PyObject *pathbytes = NULL;
94 #endif
95 PyObject *name_unicode = NULL, *name = NULL, *path = NULL, *m = NULL;
96 const char *name_buf, *hook_prefix;
97 const char *oldcontext;
98 dl_funcptr exportfunc;
99 PyModuleDef *def;
100 PyObject *(*p0)(void);
101
102 name_unicode = PyObject_GetAttrString(spec, "name");
103 if (name_unicode == NULL) {
104 return NULL;
105 }
106 if (!PyUnicode_Check(name_unicode)) {
107 PyErr_SetString(PyExc_TypeError,
108 "spec.name must be a string");
109 goto error;
110 }
111
112 name = get_encoded_name(name_unicode, &hook_prefix);
113 if (name == NULL) {
114 goto error;
115 }
116 name_buf = PyBytes_AS_STRING(name);
117
118 path = PyObject_GetAttrString(spec, "origin");
119 if (path == NULL)
120 goto error;
121
122 if (PySys_Audit("import", "OOOOO", name_unicode, path,
123 Py_None, Py_None, Py_None) < 0) {
124 return NULL;
125 }
126
127 #ifdef MS_WINDOWS
128 exportfunc = _PyImport_FindSharedFuncptrWindows(hook_prefix, name_buf,
129 path, fp);
130 #else
131 pathbytes = PyUnicode_EncodeFSDefault(path);
132 if (pathbytes == NULL)
133 goto error;
134 exportfunc = _PyImport_FindSharedFuncptr(hook_prefix, name_buf,
135 PyBytes_AS_STRING(pathbytes),
136 fp);
137 Py_DECREF(pathbytes);
138 #endif
139
140 if (exportfunc == NULL) {
141 if (!PyErr_Occurred()) {
142 PyObject *msg;
143 msg = PyUnicode_FromFormat(
144 "dynamic module does not define "
145 "module export function (%s_%s)",
146 hook_prefix, name_buf);
147 if (msg == NULL)
148 goto error;
149 PyErr_SetImportError(msg, name_unicode, path);
150 Py_DECREF(msg);
151 }
152 goto error;
153 }
154
155 p0 = (PyObject *(*)(void))exportfunc;
156
157 /* Package context is needed for single-phase init */
158 oldcontext = _Py_PackageContext;
159 _Py_PackageContext = PyUnicode_AsUTF8(name_unicode);
160 if (_Py_PackageContext == NULL) {
161 _Py_PackageContext = oldcontext;
162 goto error;
163 }
164 m = p0();
165 _Py_PackageContext = oldcontext;
166
167 if (m == NULL) {
168 if (!PyErr_Occurred()) {
169 PyErr_Format(
170 PyExc_SystemError,
171 "initialization of %s failed without raising an exception",
172 name_buf);
173 }
174 goto error;
175 } else if (PyErr_Occurred()) {
176 PyErr_Clear();
177 PyErr_Format(
178 PyExc_SystemError,
179 "initialization of %s raised unreported exception",
180 name_buf);
181 m = NULL;
182 goto error;
183 }
184 if (Py_IS_TYPE(m, NULL)) {
185 /* This can happen when a PyModuleDef is returned without calling
186 * PyModuleDef_Init on it
187 */
188 PyErr_Format(PyExc_SystemError,
189 "init function of %s returned uninitialized object",
190 name_buf);
191 m = NULL; /* prevent segfault in DECREF */
192 goto error;
193 }
194 if (PyObject_TypeCheck(m, &PyModuleDef_Type)) {
195 Py_DECREF(name_unicode);
196 Py_DECREF(name);
197 Py_DECREF(path);
198 return PyModule_FromDefAndSpec((PyModuleDef*)m, spec);
199 }
200
201 /* Fall back to single-phase init mechanism */
202
203 if (hook_prefix == nonascii_prefix) {
204 /* don't allow legacy init for non-ASCII module names */
205 PyErr_Format(
206 PyExc_SystemError,
207 "initialization of * did not return PyModuleDef",
208 name_buf);
209 goto error;
210 }
211
212 /* Remember pointer to module init function. */
213 def = PyModule_GetDef(m);
214 if (def == NULL) {
215 PyErr_Format(PyExc_SystemError,
216 "initialization of %s did not return an extension "
217 "module", name_buf);
218 goto error;
219 }
220 def->m_base.m_init = p0;
221
222 /* Remember the filename as the __file__ attribute */
223 if (PyModule_AddObject(m, "__file__", path) < 0)
224 PyErr_Clear(); /* Not important enough to report */
225 else
226 Py_INCREF(path);
227
228 PyObject *modules = PyImport_GetModuleDict();
229 if (_PyImport_FixupExtensionObject(m, name_unicode, path, modules) < 0)
230 goto error;
231
232 Py_DECREF(name_unicode);
233 Py_DECREF(name);
234 Py_DECREF(path);
235
236 return m;
237
238 error:
239 Py_DECREF(name_unicode);
240 Py_XDECREF(name);
241 Py_XDECREF(path);
242 Py_XDECREF(m);
243 return NULL;
244 }
245
246 #endif /* HAVE_DYNAMIC_LOADING */
247