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 #ifdef MS_WINDOWS
123 exportfunc = _PyImport_FindSharedFuncptrWindows(hook_prefix, name_buf,
124 path, fp);
125 #else
126 pathbytes = PyUnicode_EncodeFSDefault(path);
127 if (pathbytes == NULL)
128 goto error;
129 exportfunc = _PyImport_FindSharedFuncptr(hook_prefix, name_buf,
130 PyBytes_AS_STRING(pathbytes),
131 fp);
132 Py_DECREF(pathbytes);
133 #endif
134
135 if (exportfunc == NULL) {
136 if (!PyErr_Occurred()) {
137 PyObject *msg;
138 msg = PyUnicode_FromFormat(
139 "dynamic module does not define "
140 "module export function (%s_%s)",
141 hook_prefix, name_buf);
142 if (msg == NULL)
143 goto error;
144 PyErr_SetImportError(msg, name_unicode, path);
145 Py_DECREF(msg);
146 }
147 goto error;
148 }
149
150 p0 = (PyObject *(*)(void))exportfunc;
151
152 /* Package context is needed for single-phase init */
153 oldcontext = _Py_PackageContext;
154 _Py_PackageContext = PyUnicode_AsUTF8(name_unicode);
155 if (_Py_PackageContext == NULL) {
156 _Py_PackageContext = oldcontext;
157 goto error;
158 }
159 m = p0();
160 _Py_PackageContext = oldcontext;
161
162 if (m == NULL) {
163 if (!PyErr_Occurred()) {
164 PyErr_Format(
165 PyExc_SystemError,
166 "initialization of %s failed without raising an exception",
167 name_buf);
168 }
169 goto error;
170 } else if (PyErr_Occurred()) {
171 PyErr_Clear();
172 PyErr_Format(
173 PyExc_SystemError,
174 "initialization of %s raised unreported exception",
175 name_buf);
176 m = NULL;
177 goto error;
178 }
179 if (Py_TYPE(m) == NULL) {
180 /* This can happen when a PyModuleDef is returned without calling
181 * PyModuleDef_Init on it
182 */
183 PyErr_Format(PyExc_SystemError,
184 "init function of %s returned uninitialized object",
185 name_buf);
186 m = NULL; /* prevent segfault in DECREF */
187 goto error;
188 }
189 if (PyObject_TypeCheck(m, &PyModuleDef_Type)) {
190 Py_DECREF(name_unicode);
191 Py_DECREF(name);
192 Py_DECREF(path);
193 return PyModule_FromDefAndSpec((PyModuleDef*)m, spec);
194 }
195
196 /* Fall back to single-phase init mechanism */
197
198 if (hook_prefix == nonascii_prefix) {
199 /* don't allow legacy init for non-ASCII module names */
200 PyErr_Format(
201 PyExc_SystemError,
202 "initialization of * did not return PyModuleDef",
203 name_buf);
204 goto error;
205 }
206
207 /* Remember pointer to module init function. */
208 def = PyModule_GetDef(m);
209 if (def == NULL) {
210 PyErr_Format(PyExc_SystemError,
211 "initialization of %s did not return an extension "
212 "module", name_buf);
213 goto error;
214 }
215 def->m_base.m_init = p0;
216
217 /* Remember the filename as the __file__ attribute */
218 if (PyModule_AddObject(m, "__file__", path) < 0)
219 PyErr_Clear(); /* Not important enough to report */
220 else
221 Py_INCREF(path);
222
223 PyObject *modules = PyImport_GetModuleDict();
224 if (_PyImport_FixupExtensionObject(m, name_unicode, path, modules) < 0)
225 goto error;
226
227 Py_DECREF(name_unicode);
228 Py_DECREF(name);
229 Py_DECREF(path);
230
231 return m;
232
233 error:
234 Py_DECREF(name_unicode);
235 Py_XDECREF(name);
236 Py_XDECREF(path);
237 Py_XDECREF(m);
238 return NULL;
239 }
240
241 #endif /* HAVE_DYNAMIC_LOADING */
242