cpython/Python/importdl.c

/* 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"

extern dl_funcptr _PyImport_GetDynLoadFunc(const char *name,
					   const char *shortname,
					   const char *pathname, FILE *fp);



PyObject *
_PyImport_LoadDynamicModule(char *name, char *pathname, FILE *fp)
{
	PyObject *m;
	PyObject *path;
	char *lastdot, *shortname, *packagecontext, *oldcontext;
	dl_funcptr p0;
	PyObject* (*p)(void);
	struct PyModuleDef *def;

	if ((m = _PyImport_FindExtension(name, pathname)) != NULL) {
		Py_INCREF(m);
		return m;
	}
	lastdot = strrchr(name, '.');
	if (lastdot == NULL) {
		packagecontext = NULL;
		shortname = name;
	}
	else {
		packagecontext = name;
		shortname = lastdot+1;
	}

	p0 = _PyImport_GetDynLoadFunc(name, shortname, pathname, fp);
	p = (PyObject*(*)(void))p0;
	if (PyErr_Occurred())
		return NULL;
	if (p == NULL) {
		PyErr_Format(PyExc_ImportError,
		   "dynamic module does not define init function (PyInit_%.200s)",
			     shortname);
		return NULL;
	}
        oldcontext = _Py_PackageContext;
	_Py_PackageContext = packagecontext;
	m = (*p)();
	_Py_PackageContext = oldcontext;
	if (m == NULL)
		return NULL;

	if (PyErr_Occurred()) {
		Py_DECREF(m);
		PyErr_Format(PyExc_SystemError,
			     "initialization of %s raised unreported exception",
			     shortname);
		return NULL;
	}

	/* Remember pointer to module init function. */
	def = PyModule_GetDef(m);
	def->m_base.m_init = p;

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

	if (_PyImport_FixupExtension(m, name, pathname) < 0)
		return NULL;
	if (Py_VerboseFlag)
		PySys_WriteStderr(
			"import %s # dynamically loaded from %s\n",
			name, pathname);
	return m;
}

#endif /* HAVE_DYNAMIC_LOADING */