cpython/Python/importdl.c

342 lines
10 KiB
C

/* Support for dynamic loading of extension modules */
#include "Python.h"
#include "pycore_call.h"
#include "pycore_import.h"
#include "pycore_pyerrors.h" // _PyErr_FormatFromCause()
#include "pycore_pystate.h"
#include "pycore_runtime.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 "pycore_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;
/* Get the short name (substring after last dot) */
name_len = PyUnicode_GetLength(name);
if (name_len < 0) {
return NULL;
}
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_CallMethod(encoded, &_Py_ID(replace), "cc", '-', '_');
if (modname == NULL)
goto error;
Py_DECREF(name);
Py_DECREF(encoded);
return modname;
error:
Py_DECREF(name);
Py_XDECREF(encoded);
return NULL;
}
void
_Py_ext_module_loader_info_clear(struct _Py_ext_module_loader_info *info)
{
Py_CLEAR(info->filename);
#ifndef MS_WINDOWS
Py_CLEAR(info->filename_encoded);
#endif
Py_CLEAR(info->name);
Py_CLEAR(info->name_encoded);
}
int
_Py_ext_module_loader_info_init(struct _Py_ext_module_loader_info *p_info,
PyObject *name, PyObject *filename)
{
struct _Py_ext_module_loader_info info = {0};
assert(name != NULL);
if (!PyUnicode_Check(name)) {
PyErr_SetString(PyExc_TypeError,
"module name must be a string");
_Py_ext_module_loader_info_clear(&info);
return -1;
}
assert(PyUnicode_GetLength(name) > 0);
info.name = Py_NewRef(name);
info.name_encoded = get_encoded_name(info.name, &info.hook_prefix);
if (info.name_encoded == NULL) {
_Py_ext_module_loader_info_clear(&info);
return -1;
}
info.newcontext = PyUnicode_AsUTF8(info.name);
if (info.newcontext == NULL) {
_Py_ext_module_loader_info_clear(&info);
return -1;
}
if (filename != NULL) {
if (!PyUnicode_Check(filename)) {
PyErr_SetString(PyExc_TypeError,
"module filename must be a string");
_Py_ext_module_loader_info_clear(&info);
return -1;
}
info.filename = Py_NewRef(filename);
#ifndef MS_WINDOWS
info.filename_encoded = PyUnicode_EncodeFSDefault(info.filename);
if (info.filename_encoded == NULL) {
_Py_ext_module_loader_info_clear(&info);
return -1;
}
#endif
info.path = info.filename;
}
else {
info.path = info.name;
}
*p_info = info;
return 0;
}
int
_Py_ext_module_loader_info_init_for_builtin(
struct _Py_ext_module_loader_info *info,
PyObject *name)
{
assert(PyUnicode_Check(name));
assert(PyUnicode_FindChar(name, '.', 0, PyUnicode_GetLength(name), -1) == -1);
assert(PyUnicode_GetLength(name) > 0);
PyObject *name_encoded = PyUnicode_AsEncodedString(name, "ascii", NULL);
if (name_encoded == NULL) {
return -1;
}
*info = (struct _Py_ext_module_loader_info){
.name=Py_NewRef(name),
.name_encoded=name_encoded,
/* We won't need filename. */
.path=name,
.hook_prefix=ascii_only_prefix,
.newcontext=NULL,
};
return 0;
}
int
_Py_ext_module_loader_info_init_from_spec(
struct _Py_ext_module_loader_info *p_info,
PyObject *spec)
{
PyObject *name = PyObject_GetAttrString(spec, "name");
if (name == NULL) {
return -1;
}
PyObject *filename = PyObject_GetAttrString(spec, "origin");
if (filename == NULL) {
Py_DECREF(name);
return -1;
}
int err = _Py_ext_module_loader_info_init(p_info, name, filename);
Py_DECREF(name);
Py_DECREF(filename);
return err;
}
PyModInitFunction
_PyImport_GetModInitFunc(struct _Py_ext_module_loader_info *info,
FILE *fp)
{
const char *name_buf = PyBytes_AS_STRING(info->name_encoded);
dl_funcptr exportfunc;
#ifdef MS_WINDOWS
exportfunc = _PyImport_FindSharedFuncptrWindows(
info->hook_prefix, name_buf, info->filename, fp);
#else
{
const char *path_buf = PyBytes_AS_STRING(info->filename_encoded);
exportfunc = _PyImport_FindSharedFuncptr(
info->hook_prefix, name_buf, path_buf, fp);
}
#endif
if (exportfunc == NULL) {
if (!PyErr_Occurred()) {
PyObject *msg;
msg = PyUnicode_FromFormat(
"dynamic module does not define "
"module export function (%s_%s)",
info->hook_prefix, name_buf);
if (msg != NULL) {
PyErr_SetImportError(msg, info->name, info->filename);
Py_DECREF(msg);
}
}
return NULL;
}
return (PyModInitFunction)exportfunc;
}
int
_PyImport_RunModInitFunc(PyModInitFunction p0,
struct _Py_ext_module_loader_info *info,
struct _Py_ext_module_loader_result *p_res)
{
struct _Py_ext_module_loader_result res = {0};
const char *name_buf = PyBytes_AS_STRING(info->name_encoded);
/* Call the module init function. */
/* Package context is needed for single-phase init */
const char *oldcontext = _PyImport_SwapPackageContext(info->newcontext);
PyObject *m = p0();
_PyImport_SwapPackageContext(oldcontext);
/* Validate the result (and populate "res". */
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_FormatFromCause(
PyExc_SystemError,
"initialization of %s raised unreported exception",
name_buf);
/* We would probably be correct to decref m here,
* but we weren't doing so before,
* so we stick with doing nothing. */
m = NULL;
goto error;
}
if (Py_IS_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);
/* Likewise, decref'ing here makes sense. However, the original
* code has a note about "prevent segfault in DECREF",
* so we play it safe and leave it alone. */
m = NULL; /* prevent segfault in DECREF */
goto error;
}
if (PyObject_TypeCheck(m, &PyModuleDef_Type)) {
/* multi-phase init */
res.def = (PyModuleDef *)m;
/* Run PyModule_FromDefAndSpec() to finish loading the module. */
}
else if (info->hook_prefix == nonascii_prefix) {
/* It should have been multi-phase init? */
/* Don't allow legacy init for non-ASCII module names. */
PyErr_Format(
PyExc_SystemError,
"initialization of %s did not return PyModuleDef",
name_buf);
Py_DECREF(m);
return -1;
}
else {
/* single-phase init (legacy) */
res.module = m;
if (!PyModule_Check(m)) {
PyErr_Format(PyExc_SystemError,
"initialization of %s did not return an extension "
"module", name_buf);
goto error;
}
res.def = _PyModule_GetDef(m);
if (res.def == NULL) {
PyErr_Format(PyExc_SystemError,
"initialization of %s did not return a valid extension "
"module", name_buf);
goto error;
}
}
assert(!PyErr_Occurred());
*p_res = res;
return 0;
error:
assert(PyErr_Occurred());
Py_CLEAR(res.module);
res.def = NULL;
*p_res = res;
return -1;
}
#endif /* HAVE_DYNAMIC_LOADING */