summaryrefslogtreecommitdiffstats
path: root/Python/importdl.c
blob: ac03289c4d23f1f91d6cebac51a434a372d9860f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231

/* Support for dynamic loading of extension modules */

#include "Python.h"

/* ./configure sets HAVE_DYNAMIC_LOADING if dynamic loading of modules is
   supported on this platform. configure will then compile and link in one
   of the dynload_*.c files, as appropriate. We will call a function in
   those modules to get a function pointer to the module's init function.
*/
#ifdef HAVE_DYNAMIC_LOADING

#include "importdl.h"

#ifdef MS_WINDOWS
extern dl_funcptr _PyImport_FindSharedFuncptrWindows(const char *prefix,
                                                     const char *shortname,
                                                     PyObject *pathname,
                                                     FILE *fp);
#else
extern dl_funcptr _PyImport_FindSharedFuncptr(const char *prefix,
                                              const char *shortname,
                                              const char *pathname, FILE *fp);
#endif

static const char * const ascii_only_prefix = "PyInit";
static const char * const nonascii_prefix = "PyInitU";

/* Get the variable part of a module's export symbol name.
 * Returns a bytes instance. For non-ASCII-named modules, the name is
 * encoded as per PEP 489.
 * The hook_prefix pointer is set to either ascii_only_prefix or
 * nonascii_prefix, as appropriate.
 */
static PyObject *
get_encoded_name(PyObject *name, const char **hook_prefix) {
    PyObject *tmp;
    PyObject *encoded = NULL;
    PyObject *modname = NULL;
    Py_ssize_t name_len, lastdot;
    _Py_IDENTIFIER(replace);

    /* Get the short name (substring after last dot) */
    name_len = PyUnicode_GetLength(name);
    lastdot = PyUnicode_FindChar(name, '.', 0, name_len, -1);
    if (lastdot < -1) {
        return NULL;
    } else if (lastdot >= 0) {
        tmp = PyUnicode_Substring(name, lastdot + 1, name_len);
        if (tmp == NULL)
            return NULL;
        name = tmp;
        /* "name" now holds a new reference to the substring */
    } else {
        Py_INCREF(name);
    }

    /* Encode to ASCII or Punycode, as needed */
    encoded = PyUnicode_AsEncodedString(name, "ascii", NULL);
    if (encoded != NULL) {
        *hook_prefix = ascii_only_prefix;
    } else {
        if (PyErr_ExceptionMatches(PyExc_UnicodeEncodeError)) {
            PyErr_Clear();
            encoded = PyUnicode_AsEncodedString(name, "punycode", NULL);
            if (encoded == NULL) {
                goto error;
            }
            *hook_prefix = nonascii_prefix;
        } else {
            goto error;
        }
    }

    /* Replace '-' by '_' */
    modname = _PyObject_CallMethodId(encoded, &PyId_replace, "cc", '-', '_');
    if (modname == NULL)
        goto error;

    Py_DECREF(name);
    Py_DECREF(encoded);
    return modname;
error:
    Py_DECREF(name);
    Py_XDECREF(encoded);
    return NULL;
}

PyObject *
_PyImport_LoadDynamicModuleWithSpec(PyObject *spec, FILE *fp)
{
#ifndef MS_WINDOWS
    PyObject *pathbytes = NULL;
#endif
    PyObject *name_unicode = NULL, *name = NULL, *path = NULL, *m = NULL;
    const char *name_buf, *hook_prefix;
    char *oldcontext;
    dl_funcptr exportfunc;
    PyModuleDef *def;
    PyObject *(*p0)(void);

    name_unicode = PyObject_GetAttrString(spec, "name");
    if (name_unicode == NULL) {
        return NULL;
    }

    name = get_encoded_name(name_unicode, &hook_prefix);
    if (name == NULL) {
        goto error;
    }
    name_buf = PyBytes_AS_STRING(name);

    path = PyObject_GetAttrString(spec, "origin");
    if (path == NULL)
        goto error;

#ifdef MS_WINDOWS
    exportfunc = _PyImport_FindSharedFuncptrWindows(hook_prefix, name_buf,
                                                    path, fp);
#else
    pathbytes = PyUnicode_EncodeFSDefault(path);
    if (pathbytes == NULL)
        goto error;
    exportfunc = _PyImport_FindSharedFuncptr(hook_prefix, name_buf,
                                             PyBytes_AS_STRING(pathbytes),
                                             fp);
    Py_DECREF(pathbytes);
#endif

    if (exportfunc == NULL) {
        if (!PyErr_Occurred()) {
            PyObject *msg;
            msg = PyUnicode_FromFormat(
                "dynamic module does not define "
                "module export function (%s_%s)",
                hook_prefix, name_buf);
            if (msg == NULL)
                goto error;
            PyErr_SetImportError(msg, name_unicode, path);
            Py_DECREF(msg);
        }
        goto error;
    }

    p0 = (PyObject *(*)(void))exportfunc;

    /* Package context is needed for single-phase init */
    oldcontext = _Py_PackageContext;
    _Py_PackageContext = PyUnicode_AsUTF8(name_unicode);
    m = p0();
    _Py_PackageContext = oldcontext;

    if (m == NULL) {
        if (!PyErr_Occurred()) {
            PyErr_Format(
                PyExc_SystemError,
                "initialization of %s failed without raising an exception",
                name_buf);
        }
        goto error;
    } else if (PyErr_Occurred()) {
        PyErr_Clear();
        PyErr_Format(
            PyExc_SystemError,
            "initialization of %s raised unreported exception",
            name_buf);
        m = NULL;
        goto error;
    }
    if (Py_TYPE(m) == NULL) {
        /* This can happen when a PyModuleDef is returned without calling
         * PyModuleDef_Init on it
         */
        PyErr_Format(PyExc_SystemError,
                     "init function of %s returned uninitialized object",
                     name_buf);
        m = NULL; /* prevent segfault in DECREF */
        goto error;
    }
    if (PyObject_TypeCheck(m, &PyModuleDef_Type)) {
        Py_DECREF(name_unicode);
        Py_DECREF(name);
        Py_DECREF(path);
        return PyModule_FromDefAndSpec((PyModuleDef*)m, spec);
    }

    /* Fall back to single-phase init mechanism */

    if (hook_prefix == nonascii_prefix) {
        /* don't allow legacy init for non-ASCII module names */
        PyErr_Format(
            PyExc_SystemError,
            "initialization of * did not return PyModuleDef",
            name_buf);
        goto error;
    }

    /* Remember pointer to module init function. */
    def = PyModule_GetDef(m);
    if (def == NULL) {
        PyErr_Format(PyExc_SystemError,
                     "initialization of %s did not return an extension "
                     "module", name_buf);
        goto error;
    }
    def->m_base.m_init = p0;

    /* Remember the filename as the __file__ attribute */
    if (PyModule_AddObject(m, "__file__", path) < 0)
        PyErr_Clear(); /* Not important enough to report */
    else
        Py_INCREF(path);

    if (_PyImport_FixupExtensionObject(m, name_unicode, path) < 0)
        goto error;

    Py_DECREF(name_unicode);
    Py_DECREF(name);
    Py_DECREF(path);

    return m;

error:
    Py_DECREF(name_unicode);
    Py_XDECREF(name);
    Py_XDECREF(path);
    Py_XDECREF(m);
    return NULL;
}

#endif /* HAVE_DYNAMIC_LOADING */