1
2 /* Support for dynamic loading of extension modules */
3
4 #include "Python.h"
5 #include "pycore_call.h"
6 #include "pycore_pystate.h"
7 #include "pycore_runtime.h"
8
9 /* ./configure sets HAVE_DYNAMIC_LOADING if dynamic loading of modules is
10 supported on this platform. configure will then compile and link in one
11 of the dynload_*.c files, as appropriate. We will call a function in
12 those modules to get a function pointer to the module's init function.
13 */
14 #ifdef HAVE_DYNAMIC_LOADING
15
16 #include "importdl.h"
17
18 #ifdef MS_WINDOWS
19 extern dl_funcptr _PyImport_FindSharedFuncptrWindows(const char *prefix,
20 const char *shortname,
21 PyObject *pathname,
22 FILE *fp);
23 #else
24 extern dl_funcptr _PyImport_FindSharedFuncptr(const char *prefix,
25 const char *shortname,
26 const char *pathname, FILE *fp);
27 #endif
28
29 static const char * const ascii_only_prefix = "PyInit";
30 static const char * const nonascii_prefix = "PyInitU";
31
32 /* Get the variable part of a module's export symbol name.
33 * Returns a bytes instance. For non-ASCII-named modules, the name is
34 * encoded as per PEP 489.
35 * The hook_prefix pointer is set to either ascii_only_prefix or
36 * nonascii_prefix, as appropriate.
37 */
38 static PyObject *
39 get_encoded_name(PyObject *name, const char **hook_prefix) {
40 PyObject *tmp;
41 PyObject *encoded = NULL;
42 PyObject *modname = NULL;
43 Py_ssize_t name_len, lastdot;
44
45 /* Get the short name (substring after last dot) */
46 name_len = PyUnicode_GetLength(name);
47 if (name_len < 0) {
48 return NULL;
49 }
50 lastdot = PyUnicode_FindChar(name, '.', 0, name_len, -1);
51 if (lastdot < -1) {
52 return NULL;
53 } else if (lastdot >= 0) {
54 tmp = PyUnicode_Substring(name, lastdot + 1, name_len);
55 if (tmp == NULL)
56 return NULL;
57 name = tmp;
58 /* "name" now holds a new reference to the substring */
59 } else {
60 Py_INCREF(name);
61 }
62
63 /* Encode to ASCII or Punycode, as needed */
64 encoded = PyUnicode_AsEncodedString(name, "ascii", NULL);
65 if (encoded != NULL) {
66 *hook_prefix = ascii_only_prefix;
67 } else {
68 if (PyErr_ExceptionMatches(PyExc_UnicodeEncodeError)) {
69 PyErr_Clear();
70 encoded = PyUnicode_AsEncodedString(name, "punycode", NULL);
71 if (encoded == NULL) {
72 goto error;
73 }
74 *hook_prefix = nonascii_prefix;
75 } else {
76 goto error;
77 }
78 }
79
80 /* Replace '-' by '_' */
81 modname = _PyObject_CallMethod(encoded, &_Py_ID(replace), "cc", '-', '_');
82 if (modname == NULL)
83 goto error;
84
85 Py_DECREF(name);
86 Py_DECREF(encoded);
87 return modname;
88 error:
89 Py_DECREF(name);
90 Py_XDECREF(encoded);
91 return NULL;
92 }
93
94 PyObject *
95 _PyImport_LoadDynamicModuleWithSpec(PyObject *spec, FILE *fp)
96 {
97 #ifndef MS_WINDOWS
98 PyObject *pathbytes = NULL;
99 #endif
100 PyObject *name_unicode = NULL, *name = NULL, *path = NULL, *m = NULL;
101 const char *name_buf, *hook_prefix;
102 const char *oldcontext;
103 dl_funcptr exportfunc;
104 PyModuleDef *def;
105 PyModInitFunction p0;
106
107 name_unicode = PyObject_GetAttrString(spec, "name");
108 if (name_unicode == NULL) {
109 return NULL;
110 }
111 if (!PyUnicode_Check(name_unicode)) {
112 PyErr_SetString(PyExc_TypeError,
113 "spec.name must be a string");
114 goto error;
115 }
116
117 name = get_encoded_name(name_unicode, &hook_prefix);
118 if (name == NULL) {
119 goto error;
120 }
121 name_buf = PyBytes_AS_STRING(name);
122
123 path = PyObject_GetAttrString(spec, "origin");
124 if (path == NULL)
125 goto error;
126
127 if (PySys_Audit("import", "OOOOO", name_unicode, path,
128 Py_None, Py_None, Py_None) < 0) {
129 goto error;
130 }
131
132 #ifdef MS_WINDOWS
133 exportfunc = _PyImport_FindSharedFuncptrWindows(hook_prefix, name_buf,
134 path, fp);
135 #else
136 pathbytes = PyUnicode_EncodeFSDefault(path);
137 if (pathbytes == NULL)
138 goto error;
139 exportfunc = _PyImport_FindSharedFuncptr(hook_prefix, name_buf,
140 PyBytes_AS_STRING(pathbytes),
141 fp);
142 Py_DECREF(pathbytes);
143 #endif
144
145 if (exportfunc == NULL) {
146 if (!PyErr_Occurred()) {
147 PyObject *msg;
148 msg = PyUnicode_FromFormat(
149 "dynamic module does not define "
150 "module export function (%s_%s)",
151 hook_prefix, name_buf);
152 if (msg == NULL)
153 goto error;
154 PyErr_SetImportError(msg, name_unicode, path);
155 Py_DECREF(msg);
156 }
157 goto error;
158 }
159
160 p0 = (PyModInitFunction)exportfunc;
161
162 /* Package context is needed for single-phase init */
163 oldcontext = _Py_PackageContext;
164 _Py_PackageContext = PyUnicode_AsUTF8(name_unicode);
165 if (_Py_PackageContext == NULL) {
166 _Py_PackageContext = oldcontext;
167 goto error;
168 }
169 m = _PyImport_InitFunc_TrampolineCall(p0);
170 _Py_PackageContext = oldcontext;
171
172 if (m == NULL) {
173 if (!PyErr_Occurred()) {
174 PyErr_Format(
175 PyExc_SystemError,
176 "initialization of %s failed without raising an exception",
177 name_buf);
178 }
179 goto error;
180 } else if (PyErr_Occurred()) {
181 PyErr_Clear();
182 PyErr_Format(
183 PyExc_SystemError,
184 "initialization of %s raised unreported exception",
185 name_buf);
186 m = NULL;
187 goto error;
188 }
189 if (Py_IS_TYPE(m, NULL)) {
190 /* This can happen when a PyModuleDef is returned without calling
191 * PyModuleDef_Init on it
192 */
193 PyErr_Format(PyExc_SystemError,
194 "init function of %s returned uninitialized object",
195 name_buf);
196 m = NULL; /* prevent segfault in DECREF */
197 goto error;
198 }
199 if (PyObject_TypeCheck(m, &PyModuleDef_Type)) {
200 Py_DECREF(name_unicode);
201 Py_DECREF(name);
202 Py_DECREF(path);
203 return PyModule_FromDefAndSpec((PyModuleDef*)m, spec);
204 }
205
206 /* Fall back to single-phase init mechanism */
207
208 if (hook_prefix == nonascii_prefix) {
209 /* don't allow legacy init for non-ASCII module names */
210 PyErr_Format(
211 PyExc_SystemError,
212 "initialization of %s did not return PyModuleDef",
213 name_buf);
214 goto error;
215 }
216
217 /* Remember pointer to module init function. */
218 def = PyModule_GetDef(m);
219 if (def == NULL) {
220 PyErr_Format(PyExc_SystemError,
221 "initialization of %s did not return an extension "
222 "module", name_buf);
223 goto error;
224 }
225 def->m_base.m_init = p0;
226
227 /* Remember the filename as the __file__ attribute */
228 if (PyModule_AddObjectRef(m, "__file__", path) < 0) {
229 PyErr_Clear(); /* Not important enough to report */
230 }
231
232 PyObject *modules = PyImport_GetModuleDict();
233 if (_PyImport_FixupExtensionObject(m, name_unicode, path, modules) < 0)
234 goto error;
235
236 Py_DECREF(name_unicode);
237 Py_DECREF(name);
238 Py_DECREF(path);
239
240 return m;
241
242 error:
243 Py_DECREF(name_unicode);
244 Py_XDECREF(name);
245 Py_XDECREF(path);
246 Py_XDECREF(m);
247 return NULL;
248 }
249
250 #endif /* HAVE_DYNAMIC_LOADING */