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
16extern dl_funcptr _PyImport_FindSharedFuncptrWindows(const char *prefix,
17 const char *shortname,
18 PyObject *pathname,
19 FILE *fp);
20#else
21extern dl_funcptr _PyImport_FindSharedFuncptr(const char *prefix,
22 const char *shortname,
23 const char *pathname, FILE *fp);
24#endif
25
26static const char * const ascii_only_prefix = "PyInit";
27static 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 */
35static PyObject *
36get_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 if (name_len < 0) {
46 return NULL;
47 }
48 lastdot = PyUnicode_FindChar(name, '.', 0, name_len, -1);
49 if (lastdot < -1) {
50 return NULL;
51 } else if (lastdot >= 0) {
52 tmp = PyUnicode_Substring(name, lastdot + 1, name_len);
53 if (tmp == NULL)
54 return NULL;
55 name = tmp;
56 /* "name" now holds a new reference to the substring */
57 } else {
58 Py_INCREF(name);
59 }
60
61 /* Encode to ASCII or Punycode, as needed */
62 encoded = PyUnicode_AsEncodedString(name, "ascii", NULL);
63 if (encoded != NULL) {
64 *hook_prefix = ascii_only_prefix;
65 } else {
66 if (PyErr_ExceptionMatches(PyExc_UnicodeEncodeError)) {
67 PyErr_Clear();
68 encoded = PyUnicode_AsEncodedString(name, "punycode", NULL);
69 if (encoded == NULL) {
70 goto error;
71 }
72 *hook_prefix = nonascii_prefix;
73 } else {
74 goto error;
75 }
76 }
77
78 /* Replace '-' by '_' */
79 modname = _PyObject_CallMethodId(encoded, &PyId_replace, "cc", '-', '_');
80 if (modname == NULL)
81 goto error;
82
83 Py_DECREF(name);
84 Py_DECREF(encoded);
85 return modname;
86error:
87 Py_DECREF(name);
88 Py_XDECREF(encoded);
89 return NULL;
90}
91
92PyObject *
93_PyImport_LoadDynamicModuleWithSpec(PyObject *spec, FILE *fp)
94{
95#ifndef MS_WINDOWS
96 PyObject *pathbytes = NULL;
97#endif
98 PyObject *name_unicode = NULL, *name = NULL, *path = NULL, *m = NULL;
99 const char *name_buf, *hook_prefix;
100 const char *oldcontext;
101 dl_funcptr exportfunc;
102 PyModuleDef *def;
103 PyObject *(*p0)(void);
104
105 name_unicode = PyObject_GetAttrString(spec, "name");
106 if (name_unicode == NULL) {
107 return NULL;
108 }
109 if (!PyUnicode_Check(name_unicode)) {
110 PyErr_SetString(PyExc_TypeError,
111 "spec.name must be a string");
112 goto error;
113 }
114
115 name = get_encoded_name(name_unicode, &hook_prefix);
116 if (name == NULL) {
117 goto error;
118 }
119 name_buf = PyBytes_AS_STRING(name);
120
121 path = PyObject_GetAttrString(spec, "origin");
122 if (path == NULL)
123 goto error;
124
125 if (PySys_Audit("import", "OOOOO", name_unicode, path,
126 Py_None, Py_None, Py_None) < 0) {
127 goto error;
128 }
129
130#ifdef MS_WINDOWS
131 exportfunc = _PyImport_FindSharedFuncptrWindows(hook_prefix, name_buf,
132 path, fp);
133#else
134 pathbytes = PyUnicode_EncodeFSDefault(path);
135 if (pathbytes == NULL)
136 goto error;
137 exportfunc = _PyImport_FindSharedFuncptr(hook_prefix, name_buf,
138 PyBytes_AS_STRING(pathbytes),
139 fp);
140 Py_DECREF(pathbytes);
141#endif
142
143 if (exportfunc == NULL) {
144 if (!PyErr_Occurred()) {
145 PyObject *msg;
146 msg = PyUnicode_FromFormat(
147 "dynamic module does not define "
148 "module export function (%s_%s)",
149 hook_prefix, name_buf);
150 if (msg == NULL)
151 goto error;
152 PyErr_SetImportError(msg, name_unicode, path);
153 Py_DECREF(msg);
154 }
155 goto error;
156 }
157
158 p0 = (PyObject *(*)(void))exportfunc;
159
160 /* Package context is needed for single-phase init */
161 oldcontext = _Py_PackageContext;
162 _Py_PackageContext = PyUnicode_AsUTF8(name_unicode);
163 if (_Py_PackageContext == NULL) {
164 _Py_PackageContext = oldcontext;
165 goto error;
166 }
167 m = p0();
168 _Py_PackageContext = oldcontext;
169
170 if (m == NULL) {
171 if (!PyErr_Occurred()) {
172 PyErr_Format(
173 PyExc_SystemError,
174 "initialization of %s failed without raising an exception",
175 name_buf);
176 }
177 goto error;
178 } else if (PyErr_Occurred()) {
179 PyErr_Clear();
180 PyErr_Format(
181 PyExc_SystemError,
182 "initialization of %s raised unreported exception",
183 name_buf);
184 m = NULL;
185 goto error;
186 }
187 if (Py_IS_TYPE(m, NULL)) {
188 /* This can happen when a PyModuleDef is returned without calling
189 * PyModuleDef_Init on it
190 */
191 PyErr_Format(PyExc_SystemError,
192 "init function of %s returned uninitialized object",
193 name_buf);
194 m = NULL; /* prevent segfault in DECREF */
195 goto error;
196 }
197 if (PyObject_TypeCheck(m, &PyModuleDef_Type)) {
198 Py_DECREF(name_unicode);
199 Py_DECREF(name);
200 Py_DECREF(path);
201 return PyModule_FromDefAndSpec((PyModuleDef*)m, spec);
202 }
203
204 /* Fall back to single-phase init mechanism */
205
206 if (hook_prefix == nonascii_prefix) {
207 /* don't allow legacy init for non-ASCII module names */
208 PyErr_Format(
209 PyExc_SystemError,
210 "initialization of %s did not return PyModuleDef",
211 name_buf);
212 goto error;
213 }
214
215 /* Remember pointer to module init function. */
216 def = PyModule_GetDef(m);
217 if (def == NULL) {
218 PyErr_Format(PyExc_SystemError,
219 "initialization of %s did not return an extension "
220 "module", name_buf);
221 goto error;
222 }
223 def->m_base.m_init = p0;
224
225 /* Remember the filename as the __file__ attribute */
226 if (PyModule_AddObjectRef(m, "__file__", path) < 0) {
227 PyErr_Clear(); /* Not important enough to report */
228 }
229
230 PyObject *modules = PyImport_GetModuleDict();
231 if (_PyImport_FixupExtensionObject(m, name_unicode, path, modules) < 0)
232 goto error;
233
234 Py_DECREF(name_unicode);
235 Py_DECREF(name);
236 Py_DECREF(path);
237
238 return m;
239
240error:
241 Py_DECREF(name_unicode);
242 Py_XDECREF(name);
243 Py_XDECREF(path);
244 Py_XDECREF(m);
245 return NULL;
246}
247
248#endif /* HAVE_DYNAMIC_LOADING */
249