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 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
107 name = get_encoded_name(name_unicode, &hook_prefix);
108 if (name == NULL) {
109 goto error;
110 }
111 name_buf = PyBytes_AS_STRING(name);
112
113 path = PyObject_GetAttrString(spec, "origin");
114 if (path == NULL)
115 goto error;
116
117 #ifdef MS_WINDOWS
118 exportfunc = _PyImport_FindSharedFuncptrWindows(hook_prefix, name_buf,
119 path, fp);
120 #else
121 pathbytes = PyUnicode_EncodeFSDefault(path);
122 if (pathbytes == NULL)
123 goto error;
124 exportfunc = _PyImport_FindSharedFuncptr(hook_prefix, name_buf,
125 PyBytes_AS_STRING(pathbytes),
126 fp);
127 Py_DECREF(pathbytes);
128 #endif
129
130 if (exportfunc == NULL) {
131 if (!PyErr_Occurred()) {
132 PyObject *msg;
133 msg = PyUnicode_FromFormat(
134 "dynamic module does not define "
135 "module export function (%s_%s)",
136 hook_prefix, name_buf);
137 if (msg == NULL)
138 goto error;
139 PyErr_SetImportError(msg, name_unicode, path);
140 Py_DECREF(msg);
141 }
142 goto error;
143 }
144
145 p0 = (PyObject *(*)(void))exportfunc;
146
147 /* Package context is needed for single-phase init */
148 oldcontext = _Py_PackageContext;
149 _Py_PackageContext = PyUnicode_AsUTF8(name_unicode);
150 if (_Py_PackageContext == NULL) {
151 _Py_PackageContext = oldcontext;
152 goto error;
153 }
154 m = p0();
155 _Py_PackageContext = oldcontext;
156
157 if (m == NULL) {
158 if (!PyErr_Occurred()) {
159 PyErr_Format(
160 PyExc_SystemError,
161 "initialization of %s failed without raising an exception",
162 name_buf);
163 }
164 goto error;
165 } else if (PyErr_Occurred()) {
166 PyErr_Clear();
167 PyErr_Format(
168 PyExc_SystemError,
169 "initialization of %s raised unreported exception",
170 name_buf);
171 m = NULL;
172 goto error;
173 }
174 if (Py_TYPE(m) == NULL) {
175 /* This can happen when a PyModuleDef is returned without calling
176 * PyModuleDef_Init on it
177 */
178 PyErr_Format(PyExc_SystemError,
179 "init function of %s returned uninitialized object",
180 name_buf);
181 m = NULL; /* prevent segfault in DECREF */
182 goto error;
183 }
184 if (PyObject_TypeCheck(m, &PyModuleDef_Type)) {
185 Py_DECREF(name_unicode);
186 Py_DECREF(name);
187 Py_DECREF(path);
188 return PyModule_FromDefAndSpec((PyModuleDef*)m, spec);
189 }
190
191 /* Fall back to single-phase init mechanism */
192
193 if (hook_prefix == nonascii_prefix) {
194 /* don't allow legacy init for non-ASCII module names */
195 PyErr_Format(
196 PyExc_SystemError,
197 "initialization of * did not return PyModuleDef",
198 name_buf);
199 goto error;
200 }
201
202 /* Remember pointer to module init function. */
203 def = PyModule_GetDef(m);
204 if (def == NULL) {
205 PyErr_Format(PyExc_SystemError,
206 "initialization of %s did not return an extension "
207 "module", name_buf);
208 goto error;
209 }
210 def->m_base.m_init = p0;
211
212 /* Remember the filename as the __file__ attribute */
213 if (PyModule_AddObject(m, "__file__", path) < 0)
214 PyErr_Clear(); /* Not important enough to report */
215 else
216 Py_INCREF(path);
217
218 if (_PyImport_FixupExtensionObject(m, name_unicode, path) < 0)
219 goto error;
220
221 Py_DECREF(name_unicode);
222 Py_DECREF(name);
223 Py_DECREF(path);
224
225 return m;
226
227 error:
228 Py_DECREF(name_unicode);
229 Py_XDECREF(name);
230 Py_XDECREF(path);
231 Py_XDECREF(m);
232 return NULL;
233 }
234
235 #endif /* HAVE_DYNAMIC_LOADING */
236