Commit message: Local privilege escalation when using daemon mode. (CVE-2014-0240)
CVE: CVE-2014-0240
CWE: CWE-264
Vulnerability description: The mod_wsgi module before 3.5 for Apache, when daemon mode is enabled, does not properly handle error codes returned by setuid when run on certain Linux kernels, which allows local users to gain privileges via vectors related to the number of running processes.

Project: mod_wsgi
File: mod_wsgi.c

static PyObject *ShutdownInterpreter_call(
        ShutdownInterpreterObject *self, PyObject *args, PyObject *kwds)
{
    PyObject *result = NULL;

    result = PyObject_Call(self->wrapped, args, kwds);

    if (result) {
        PyObject *module = NULL;
        PyObject *exitfunc = NULL;

        PyThreadState *tstate = PyThreadState_Get();

        PyThreadState *tstate_save = tstate;
        PyThreadState *tstate_next = NULL;

#if PY_MAJOR_VERSION >= 3
        module = PyImport_ImportModule("atexit");

        if (module) {
            PyObject *dict = NULL;

            dict = PyModule_GetDict(module);
            exitfunc = PyDict_GetItemString(dict, "_run_exitfuncs");
        }
        else
            PyErr_Clear();
#else
        exitfunc = PySys_GetObject("exitfunc");
#endif

        if (exitfunc) {
            PyObject *res = NULL;
            Py_INCREF(exitfunc);
            PySys_SetObject("exitfunc", (PyObject *)NULL);
            res = PyEval_CallObject(exitfunc, (PyObject *)NULL);

            if (res == NULL) {
                PyObject *m = NULL;
                PyObject *result = NULL;

                PyObject *type = NULL;
                PyObject *value = NULL;
                PyObject *traceback = NULL;

                if (PyErr_ExceptionMatches(PyExc_SystemExit)) {
                    Py_BEGIN_ALLOW_THREADS
                    ap_log_error(APLOG_MARK, APLOG_ERR, 0, wsgi_server,
                                 "mod_wsgi (pid=%d): SystemExit exception "
                                 "raised by exit functions ignored.", getpid());
                    Py_END_ALLOW_THREADS
                }
                else {
                    Py_BEGIN_ALLOW_THREADS
                    ap_log_error(APLOG_MARK, APLOG_ERR, 0, wsgi_server,
                                 "mod_wsgi (pid=%d): Exception occurred within "
                                 "exit functions.", getpid());
                    Py_END_ALLOW_THREADS
                }

                PyErr_Fetch(&type, &value, &traceback);
                PyErr_NormalizeException(&type, &value, &traceback);

                if (!value) {
                    value = Py_None;
                    Py_INCREF(value);
                }

                if (!traceback) {
                    traceback = Py_None;
                    Py_INCREF(traceback);
                }

                m = PyImport_ImportModule("traceback");

                if (m) {
                    PyObject *d = NULL;
                    PyObject *o = NULL;
                    d = PyModule_GetDict(m);
                    o = PyDict_GetItemString(d, "print_exception");
                    if (o) {
                        PyObject *log = NULL;
                        PyObject *args = NULL;
                        Py_INCREF(o);
                        log = newLogObject(NULL, APLOG_ERR, NULL);
                        args = Py_BuildValue("(OOOOO)", type, value,
                                             traceback, Py_None, log);
                        result = PyEval_CallObject(o, args);
                        Py_DECREF(args);
                        Py_DECREF(log);
                        Py_DECREF(o);
                    }
                }

                if (!result) {
                    /*
                     * If can't output exception and traceback then
                     * use PyErr_Print to dump out details of the
                     * exception. For SystemExit though if we do
                     * that the process will actually be terminated
                     * so can only clear the exception information
                     * and keep going.
                     */

                    PyErr_Restore(type, value, traceback);

                    if (!PyErr_ExceptionMatches(PyExc_SystemExit)) {
                        PyErr_Print();
                        PyErr_Clear();
                    }
                    else {
                        PyErr_Clear();
                    }
                }
                else {
                    Py_XDECREF(type);
                    Py_XDECREF(value);
                    Py_XDECREF(traceback);
                }

                Py_XDECREF(result);

                Py_XDECREF(m);
            }

            Py_XDECREF(res);
            Py_DECREF(exitfunc);
        }

        Py_XDECREF(module);

        /* Delete remaining thread states. */

        PyThreadState_Swap(NULL);

        tstate = tstate->interp->tstate_head;
        while (tstate) {
            tstate_next = tstate->next;
            if (tstate != tstate_save) {
                PyThreadState_Swap(tstate);
                PyThreadState_Clear(tstate);
                PyThreadState_Swap(NULL);
                PyThreadState_Delete(tstate);
            }
            tstate = tstate_next;
        }
        tstate = tstate_save;

        PyThreadState_Swap(tstate);
    }

    return result;
}

Project: mod_wsgi
File: mod_wsgi.c

static void Interpreter_dealloc(InterpreterObject *self)
{
    PyThreadState *tstate = NULL;
    PyObject *exitfunc = NULL;
    PyObject *module = NULL;

    PyThreadState *tstate_enter = NULL;

    /*
     * We should always enter here with the Python GIL
     * held and an active thread state. This should only
     * now occur when shutting down interpreter and not
     * when releasing interpreter as don't support
     * recyling of interpreters within the process. Thus
     * the thread state should be that for the main
     * Python interpreter. Where dealing with a named
     * sub interpreter, we need to change the thread
     * state to that which was originally used to create
     * that sub interpreter before doing anything.
     */

    tstate_enter = PyThreadState_Get();

    if (*self->name) {
#if APR_HAS_THREADS
        int thread_id = 0;
        int *thread_handle = NULL;

        apr_threadkey_private_get((void**)&thread_handle, wsgi_thread_key);

        if (!thread_handle) {
            thread_id = wsgi_thread_count++;
            thread_handle = (int*)apr_pmemdup(wsgi_server->process->pool,
                                              &thread_id, sizeof(thread_id));
            apr_threadkey_private_set(thread_handle, wsgi_thread_key);
        }
        else {
            thread_id = *thread_handle;
        }

        tstate = apr_hash_get(self->tstate_table, &thread_id,
                              sizeof(thread_id));

        if (!tstate) {
            tstate = PyThreadState_New(self->interp);

            if (wsgi_server_config->verbose_debugging) {
                ap_log_error(APLOG_MARK, WSGI_LOG_DEBUG(0), wsgi_server,
                             "mod_wsgi (pid=%d): Create thread state for "
                             "thread %d against interpreter '%s'.", getpid(),
                             thread_id, self->name);
            }

            apr_hash_set(self->tstate_table, thread_handle,
                         sizeof(*thread_handle), tstate);
        }
#else
        tstate = self->tstate;
#endif

        /*
         * Swap to interpreter thread state that was used when
         * the sub interpreter was created.
         */

        PyThreadState_Swap(tstate);
    }

    if (self->owner) {
        Py_BEGIN_ALLOW_THREADS
        ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0), wsgi_server,
                     "mod_wsgi (pid=%d): Destroy interpreter '%s'.",
                     getpid(), self->name);
        Py_END_ALLOW_THREADS
    }
    else {
        Py_BEGIN_ALLOW_THREADS
        ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0), wsgi_server,
                     "mod_wsgi (pid=%d): Cleanup interpreter '%s'.",
                     getpid(), self->name);
        Py_END_ALLOW_THREADS
    }

    /*
     * Because the thread state we are using was created outside
     * of any Python code and is not the same as the Python main
     * thread, there is no record of it within the 'threading'
     * module. We thus need to access current thread function of
     * the 'threading' module to force it to create a thread
     * handle for the thread. If we do not do this, then the
     * 'threading' modules exit function will always fail
     * because it will not be able to find a handle for this
     * thread.
     */

    module = PyImport_ImportModule("threading");

    if (!module)
        PyErr_Clear();

    if (module) {
        PyObject *dict = NULL;
        PyObject *func = NULL;

        dict = PyModule_GetDict(module);
#if PY_MAJOR_VERSION >= 3
        func = PyDict_GetItemString(dict, "current_thread");
#else
        func = PyDict_GetItemString(dict, "currentThread");
#endif
        if (func) {
            PyObject *res = NULL;
            Py_INCREF(func);
            res = PyEval_CallObject(func, (PyObject *)NULL);
            if (!res) {
                PyErr_Clear();
            }
            Py_XDECREF(res);
            Py_DECREF(func);
        }
    }

    /*
     * In Python 2.5.1 an exit function is no longer used to
     * shutdown and wait on non daemon threads which were created
     * from Python code. Instead, in Py_Main() it explicitly
     * calls 'threading._shutdown()'. Thus need to emulate this
     * behaviour for those versions.
     */

#if PY_MAJOR_VERSION < 3 || (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION < 4)
    if (module) {
        PyObject *dict = NULL;
        PyObject *func = NULL;

        dict = PyModule_GetDict(module);
        func = PyDict_GetItemString(dict, "_shutdown");
        if (func) {
            PyObject *res = NULL;
            Py_INCREF(func);
            res = PyEval_CallObject(func, (PyObject *)NULL);

            if (res == NULL) {
                PyObject *m = NULL;
                PyObject *result = NULL;

                PyObject *type = NULL;
                PyObject *value = NULL;
                PyObject *traceback = NULL;

                Py_BEGIN_ALLOW_THREADS
                ap_log_error(APLOG_MARK, WSGI_LOG_ERR(0), wsgi_server,
                             "mod_wsgi (pid=%d): Exception occurred within "
                             "threading._shutdown().", getpid());
                Py_END_ALLOW_THREADS

                PyErr_Fetch(&type, &value, &traceback);
                PyErr_NormalizeException(&type, &value, &traceback);

                if (!value) {
                    value = Py_None;
                    Py_INCREF(value);
                }

                if (!traceback) {
                    traceback = Py_None;
                    Py_INCREF(traceback);
                }

                m = PyImport_ImportModule("traceback");

                if (m) {
                    PyObject *d = NULL;
                    PyObject *o = NULL;
                    d = PyModule_GetDict(m);
                    o = PyDict_GetItemString(d, "print_exception");
                    if (o) {
                        PyObject *log = NULL;
                        PyObject *args = NULL;
                        Py_INCREF(o);
                        log = newLogObject(NULL, APLOG_ERR, NULL);
                        args = Py_BuildValue("(OOOOO)", type, value,
                                             traceback, Py_None, log);
                        result = PyEval_CallObject(o, args);
                        Py_DECREF(args);
                        Py_DECREF(log);
                        Py_DECREF(o);
                    }
                }

                if (!result) {
                    /*
                     * If can't output exception and traceback then
                     * use PyErr_Print to dump out details of the
                     * exception. For SystemExit though if we do
                     * that the process will actually be terminated
                     * so can only clear the exception information
                     * and keep going.
                     */

                    PyErr_Restore(type, value, traceback);

                    if (!PyErr_ExceptionMatches(PyExc_SystemExit)) {
                        PyErr_Print();
                        PyErr_Clear();
                    }
                    else {
                        PyErr_Clear();
                    }
                }
                else {
                    Py_XDECREF(type);
                    Py_XDECREF(value);
                    Py_XDECREF(traceback);
                }

                Py_XDECREF(result);

                Py_XDECREF(m);
            }

            Py_XDECREF(res);
            Py_DECREF(func);
        }
    }

    /* Finally done with 'threading' module. */

    Py_XDECREF(module);

    /*
     * Invoke exit functions by calling sys.exitfunc() for
     * Python 2.X and atexit._run_exitfuncs() for Python 3.X.
     * Note that in Python 3.X we can't call this on main Python
     * interpreter as for Python 3.X it doesn't deregister
     * functions as called, so have no choice but to rely on
     * Py_Finalize() to do it for the main interpreter. Now
     * that simplified GIL state API usage sorted out, this
     * should be okay.
     */

    module = NULL;

#if PY_MAJOR_VERSION >= 3
    if (self->owner) {
        module = PyImport_ImportModule("atexit");

        if (module) {
            PyObject *dict = NULL;

            dict = PyModule_GetDict(module);
            exitfunc = PyDict_GetItemString(dict, "_run_exitfuncs");
        }
        else
            PyErr_Clear();
    }
#else
    exitfunc = PySys_GetObject("exitfunc");
#endif

    if (exitfunc) {
        PyObject *res = NULL;
        Py_INCREF(exitfunc);
        PySys_SetObject("exitfunc", (PyObject *)NULL);
        res = PyEval_CallObject(exitfunc, (PyObject *)NULL);

        if (res == NULL) {
            PyObject *m = NULL;
            PyObject *result = NULL;

            PyObject *type = NULL;
            PyObject *value = NULL;
            PyObject *traceback = NULL;

            if (PyErr_ExceptionMatches(PyExc_SystemExit)) {
                Py_BEGIN_ALLOW_THREADS
                ap_log_error(APLOG_MARK, WSGI_LOG_ERR(0), wsgi_server,
                             "mod_wsgi (pid=%d): SystemExit exception "
                             "raised by exit functions ignored.", getpid());
                Py_END_ALLOW_THREADS
            }
            else {
                Py_BEGIN_ALLOW_THREADS
                ap_log_error(APLOG_MARK, WSGI_LOG_ERR(0), wsgi_server,
                             "mod_wsgi (pid=%d): Exception occurred within "
                             "exit functions.", getpid());
                Py_END_ALLOW_THREADS
            }

            PyErr_Fetch(&type, &value, &traceback);
            PyErr_NormalizeException(&type, &value, &traceback);

            if (!value) {
                value = Py_None;
                Py_INCREF(value);
            }

            if (!traceback) {
                traceback = Py_None;
                Py_INCREF(traceback);
            }

            m = PyImport_ImportModule("traceback");

            if (m) {
                PyObject *d = NULL;
                PyObject *o = NULL;
                d = PyModule_GetDict(m);
                o = PyDict_GetItemString(d, "print_exception");
                if (o) {
                    PyObject *log = NULL;
                    PyObject *args = NULL;
                    Py_INCREF(o);
                    log = newLogObject(NULL, APLOG_ERR, NULL);
                    args = Py_BuildValue("(OOOOO)", type, value,
                                         traceback, Py_None, log);
                    result = PyEval_CallObject(o, args);
                    Py_DECREF(args);
                    Py_DECREF(log);
                    Py_DECREF(o);
                }
            }

            if (!result) {
                /*
                 * If can't output exception and traceback then
                 * use PyErr_Print to dump out details of the
                 * exception. For SystemExit though if we do
                 * that the process will actually be terminated
                 * so can only clear the exception information
                 * and keep going.
                 */

                PyErr_Restore(type, value, traceback);

                if (!PyErr_ExceptionMatches(PyExc_SystemExit)) {
                    PyErr_Print();
                    PyErr_Clear();
                }
                else {
                    PyErr_Clear();
                }
            }
            else {
                Py_XDECREF(type);
                Py_XDECREF(value);
                Py_XDECREF(traceback);
            }

            Py_XDECREF(result);

            Py_XDECREF(m);
        }

        Py_XDECREF(res);
        Py_DECREF(exitfunc);
    }

    Py_XDECREF(module);
#endif

    /* If we own it, we destroy it. */

    if (self->owner) {
        /*
         * We need to destroy all the thread state objects
         * associated with the interpreter. If there are
         * background threads that were created then this
         * may well cause them to crash the next time they
         * try to run. Only saving grace is that we are
         * trying to shutdown the process.
         */

#if PY_MAJOR_VERSION < 3 || (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION < 4)
        PyThreadState *tstate_save = tstate;
        PyThreadState *tstate_next = NULL;

        PyThreadState_Swap(NULL);

        tstate = tstate->interp->tstate_head;
        while (tstate) {
            tstate_next = tstate->next;
            if (tstate != tstate_save) {
                PyThreadState_Swap(tstate);
                PyThreadState_Clear(tstate);
                PyThreadState_Swap(NULL);
                PyThreadState_Delete(tstate);
            }
            tstate = tstate_next;
        }
        tstate = tstate_save;

        PyThreadState_Swap(tstate);
#endif

        /* Can now destroy the interpreter. */

        Py_BEGIN_ALLOW_THREADS
        ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0), wsgi_server,
                     "mod_wsgi (pid=%d): End interpreter '%s'.",
                     getpid(), self->name);
        Py_END_ALLOW_THREADS

        Py_EndInterpreter(tstate);

        PyThreadState_Swap(tstate_enter);
    }

    free(self->name);

    PyObject_Del(self);
}

Project: mod_wsgi
File: mod_wsgi.c

static void wsgi_manage_process(int reason, void *data, apr_wait_t status)
{
    WSGIDaemonProcess *daemon = data;

    switch (reason) {

        /* Child daemon process has died. */

        case APR_OC_REASON_DEATH: {
            int mpm_state;
            int stopping;

            /* Stop watching the existing process. */

            apr_proc_other_child_unregister(daemon);

            /*
             * Determine if Apache is being shutdown or not and
             * if it is not being shutdown, restart the child
             * daemon process that has died. If MPM doesn't
             * support query assume that child daemon process
             * shouldn't be restarted. Both prefork and worker
             * MPMs support this query so should always be okay.
             */

            stopping = 1;

            if (ap_mpm_query(AP_MPMQ_MPM_STATE, &mpm_state) == APR_SUCCESS
                && mpm_state != AP_MPMQ_STOPPING) {
                stopping = 0;
            }

            if (!stopping) {
                ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0),
                             wsgi_server, "mod_wsgi (pid=%d): "
                             "Process '%s' has died, restarting.",
                             daemon->process.pid, daemon->group->name);

                if (WIFEXITED(status)) {
                    ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0),
                             wsgi_server, "mod_wsgi (pid=%d): "
                             "Process '%s' terminated normally, exit code %d", 
                             daemon->process.pid, daemon->group->name,
                             WEXITSTATUS(status));
                }
                else if (WIFSIGNALED(status)) {
                    ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0),
                             wsgi_server, "mod_wsgi (pid=%d): "
                             "Process '%s' terminated by signal %d", 
                             daemon->process.pid, daemon->group->name,
                             WTERMSIG(status));
                }

                wsgi_start_process(wsgi_parent_pool, daemon);
            }

            break;
        }

        /* Apache is being restarted or shutdown. */

        case APR_OC_REASON_RESTART: {

            /* Stop watching the existing process. */

            apr_proc_other_child_unregister(daemon);

            break;
        }

        /* Child daemon process vanished. */

        case APR_OC_REASON_LOST: {

            /* Stop watching the existing process. */

            apr_proc_other_child_unregister(daemon);

            /* Restart the child daemon process that has died. */

            ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0),
                         wsgi_server, "mod_wsgi (pid=%d): "
                         "Process '%s' has died, restarting.",
                         daemon->process.pid, daemon->group->name);

            wsgi_start_process(wsgi_parent_pool, daemon);

            break;
        }

        /* Call to unregister the process. */

        case APR_OC_REASON_UNREGISTER: {

            /* Nothing to do at present. */

            break;
        }
    }
}

Project: mod_wsgi
File: mod_wsgi.c

static void wsgi_python_child_init(apr_pool_t *p)
{
    PyGILState_STATE state;
    PyInterpreterState *interp = NULL;
    PyObject *object = NULL;

    int thread_id = 0;
    int *thread_handle = NULL;

    /* Working with Python, so must acquire GIL. */

    state = PyGILState_Ensure();

    /*
     * Trigger any special Python stuff required after a fork.
     * Only do this though if we were responsible for the
     * initialisation of the Python interpreter in the first
     * place to avoid it being done multiple times. Also only
     * do it if Python was initialised in parent process.
     */

    if (wsgi_python_initialized && !wsgi_python_after_fork)
        PyOS_AfterFork();

    /* Finalise any Python objects required by child process. */

    PyType_Ready(&Log_Type);
    PyType_Ready(&Stream_Type);
    PyType_Ready(&Input_Type);
    PyType_Ready(&Adapter_Type);
    PyType_Ready(&Restricted_Type);
    PyType_Ready(&Interpreter_Type);
    PyType_Ready(&ShutdownInterpreter_Type);
    PyType_Ready(&Dispatch_Type);

#if defined(MOD_WSGI_WITH_AAA_HANDLERS)
    PyType_Ready(&Auth_Type);
#endif

    /* Initialise Python interpreter instance table and lock. */

    wsgi_interpreters = PyDict_New();

#if APR_HAS_THREADS
    apr_thread_mutex_create(&wsgi_interp_lock, APR_THREAD_MUTEX_UNNESTED, p);
    apr_thread_mutex_create(&wsgi_module_lock, APR_THREAD_MUTEX_UNNESTED, p);
#endif

    /*
     * Initialise the key for data related to a thread. At
     * the moment we only record an integer thread ID to be
     * used in lookup table to thread states associated with
     * an interprter.
     */

#if APR_HAS_THREADS
    apr_threadkey_private_create(&wsgi_thread_key, NULL, p);

    thread_id = wsgi_thread_count++;
    thread_handle = (int*)apr_pmemdup(wsgi_server->process->pool,
                                      &thread_id, sizeof(thread_id));
    apr_threadkey_private_set(thread_handle, wsgi_thread_key);
#endif

    /*
     * Cache a reference to the first Python interpreter
     * instance. This interpreter is special as some third party
     * Python modules will only work when used from within this
     * interpreter. This is generally when they use the Python
     * simplified GIL API or otherwise don't use threading API
     * properly. An empty string for name is used to identify
     * the first Python interpreter instance.
     */

    object = (PyObject *)newInterpreterObject(NULL);
    PyDict_SetItemString(wsgi_interpreters, "", object);
    Py_DECREF(object);

    /* Restore the prior thread state and release the GIL. */

    PyGILState_Release(state);

    /* Register cleanups to performed on process shutdown. */

#if AP_SERVER_MAJORVERSION_NUMBER < 2
    ap_register_cleanup(p, NULL, wsgi_python_child_cleanup,
                        ap_null_cleanup);
#else
    apr_pool_cleanup_register(p, NULL, wsgi_python_child_cleanup,
                              apr_pool_cleanup_null);
#endif

    /* Loop through import scripts for this process and load them. */

    if (wsgi_import_list) {
        apr_array_header_t *scripts = NULL;

        WSGIScriptFile *entries;
        WSGIScriptFile *entry;

        int i;

        scripts = wsgi_import_list;
        entries = (WSGIScriptFile *)scripts->elts;

        for (i = 0; i < scripts->nelts; ++i) {
            int l = 0;

            entry = &entries[i];

            if (!strcmp(wsgi_daemon_group, entry->process_group)) {
                InterpreterObject *interp = NULL;
                PyObject *modules = NULL;
                PyObject *module = NULL;
                char *name = NULL;
                int exists = 0;

                interp = wsgi_acquire_interpreter(entry->application_group);

                if (!interp) {
                    ap_log_error(APLOG_MARK, WSGI_LOG_CRIT(0), wsgi_server,
                                  "mod_wsgi (pid=%d): Cannot acquire "
                                  "interpreter '%s'.", getpid(),
                                  entry->application_group);
                }

                /* Calculate the Python module name to be used for script. */

                name = wsgi_module_name(p, entry->handler_script);

                /*
                 * Use a lock around the check to see if the module is
                 * already loaded and the import of the module. Strictly
                 * speaking shouldn't be required at this point.
                 */

#if APR_HAS_THREADS
                Py_BEGIN_ALLOW_THREADS
                apr_thread_mutex_lock(wsgi_module_lock);
                Py_END_ALLOW_THREADS
#endif

                modules = PyImport_GetModuleDict();
                module = PyDict_GetItemString(modules, name);

                Py_XINCREF(module);

                if (module)
                    exists = 1;

                /*
                 * If script reloading is enabled and the module for it has
                 * previously been loaded, see if it has been modified since
                 * the last time it was accessed.
                 */

                if (module && wsgi_server_config->script_reloading) {
                    if (wsgi_reload_required(p, NULL, entry->handler_script,
                                             module, NULL)) {
                        /*
                         * Script file has changed. Only support module
                         * reloading for dispatch scripts. Remove the
                         * module from the modules dictionary before
                         * reloading it again. If code is executing within
                         * the module at the time, the callers reference
                         * count on the module should ensure it isn't
                         * actually destroyed until it is finished.
                         */

                        Py_DECREF(module);
                        module = NULL;

                        PyDict_DelItemString(modules, name);
                    }
                }

                if (!module) {
                    module = wsgi_load_source(p, NULL, name, exists,
                                              entry->handler_script,
                                              entry->process_group,
                                              entry->application_group);

                    if (PyErr_Occurred()) 
                        PyErr_Clear(); 
                }

                /* Safe now to release the module lock. */

#if APR_HAS_THREADS
                apr_thread_mutex_unlock(wsgi_module_lock);
#endif

                /* Cleanup and release interpreter, */

                Py_XDECREF(module);

                wsgi_release_interpreter(interp);
            }
        }
    }
}

Project: mod_wsgi
File: mod_wsgi.c

static InterpreterObject *newInterpreterObject(const char *name)
{
    PyInterpreterState *interp = NULL;
    InterpreterObject *self = NULL;
    PyThreadState *tstate = NULL;
    PyThreadState *save_tstate = NULL;
    PyObject *module = NULL;
    PyObject *object = NULL;
    PyObject *item = NULL;

    /* Create handle for interpreter and local data. */

    self = PyObject_New(InterpreterObject, &Interpreter_Type);
    if (self == NULL)
        return NULL;

    /*
     * If interpreter not named, then we want to bind
     * to the first Python interpreter instance created.
     * Give this interpreter an empty string as name.
     */

    if (!name) {
        interp = PyInterpreterState_Head();
        while (interp->next)
            interp = interp->next;

        name = "";
    }

    /* Save away the interpreter name. */

    self->name = strdup(name);

    if (interp) {
        /*
         * Interpreter provided to us so will not be
         * responsible for deleting it later. This will
         * be the case for the main Python interpreter.
         */

        ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0), wsgi_server,
                     "mod_wsgi (pid=%d): Attach interpreter '%s'.",
                     getpid(), name);

        self->interp = interp;
        self->owner = 0;
    }
    else {
        PyObject *module = NULL;

        /*
         * Remember active thread state so can restore
         * it. This is actually the thread state
         * associated with simplified GIL state API.
         */

        save_tstate = PyThreadState_Swap(NULL);

        /*
         * Create the interpreter. If creation of the
         * interpreter fails it will restore the
         * existing active thread state for us so don't
         * need to worry about it in that case.
         */

        tstate = Py_NewInterpreter();

        if (!tstate) {
            PyErr_SetString(PyExc_RuntimeError, "Py_NewInterpreter() failed");

            Py_DECREF(self);

            return NULL;
        }

        Py_BEGIN_ALLOW_THREADS
        ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0), wsgi_server,
                     "mod_wsgi (pid=%d): Create interpreter '%s'.",
                     getpid(), name);
        Py_END_ALLOW_THREADS

        self->interp = tstate->interp;
        self->owner = 1;

        /*
         * We need to replace threading._shutdown() with our own
         * function which will also call atexit callbacks after
         * threads are shutdown to cope with fact that Python
         * itself doesn't call the atexit callbacks in sub
         * interpreters.
         */

#if PY_MAJOR_VERSION > 3 || (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 4)
        module = PyImport_ImportModule("threading");

        if (module) {
            PyObject *dict = NULL;
            PyObject *func = NULL;

            dict = PyModule_GetDict(module);
            func = PyDict_GetItemString(dict, "_shutdown");

            if (func) {
                PyObject *wrapper = NULL;

                wrapper = newShutdownInterpreterObject(func);
                PyDict_SetItemString(dict, "_shutdown", wrapper);
                Py_DECREF(wrapper);
            }
        }

        Py_XDECREF(module);
#endif
    }

    /*
     * Install restricted objects for STDIN and STDOUT,
     * or log object for STDOUT as appropriate. Don't do
     * this if not running on Win32 and we believe we
     * are running in single process mode, otherwise
     * it prevents use of interactive debuggers such as
     * the 'pdb' module.
     */

    object = newLogObject(NULL, APLOG_ERR, "stderr");
    PySys_SetObject("stderr", object);
    Py_DECREF(object);

#ifndef WIN32
    if (wsgi_parent_pid != getpid()) {
#endif
        if (wsgi_server_config->restrict_stdout == 1) {
            object = (PyObject *)newRestrictedObject("sys.stdout");
            PySys_SetObject("stdout", object);
            Py_DECREF(object);
        }
        else {
            object = newLogObject(NULL, APLOG_ERR, "stdout");
            PySys_SetObject("stdout", object);
            Py_DECREF(object);
        }

        if (wsgi_server_config->restrict_stdin == 1) {
            object = (PyObject *)newRestrictedObject("sys.stdin");
            PySys_SetObject("stdin", object);
            Py_DECREF(object);
        }
#ifndef WIN32
    }
#endif

    /*
     * Set sys.argv to one element list to fake out
     * modules that look there for Python command
     * line arguments as appropriate.
     */

    object = PyList_New(0);
#if PY_MAJOR_VERSION >= 3
    item = PyUnicode_FromString("mod_wsgi");
#else
    item = PyString_FromString("mod_wsgi");
#endif
    PyList_Append(object, item);
    PySys_SetObject("argv", object);
    Py_DECREF(item);
    Py_DECREF(object);

    /*
     * Install intercept for signal handler registration
     * if appropriate.
     */

    if (wsgi_server_config->restrict_signal != 0) {
        module = PyImport_ImportModule("signal");
        PyModule_AddObject(module, "signal", PyCFunction_New(
                           &wsgi_signal_method[0], NULL));
        Py_DECREF(module);
    }

    /*
     * Force loading of codecs into interpreter. This has to be
     * done as not otherwise done in sub interpreters and if not
     * done, code running in sub interpreters can fail on some
     * platforms if a unicode string is added in sys.path and an
     * import then done.
     */

    item = PyCodec_Encoder("ascii");
    Py_XDECREF(item);

    /*
     * If running in daemon process, override as appropriate
     * the USER, USERNAME or LOGNAME environment  variables
     * so that they match the user that the process is running
     * as. Need to do this else we inherit the value from the
     * Apache parent process which is likely wrong as will be
     * root or the user than ran sudo when Apache started.
     * Can't update these for normal Apache child processes
     * as that would change the expected environment of other
     * Apache modules.
     */

#ifndef WIN32
    if (wsgi_daemon_pool) {
        module = PyImport_ImportModule("os");

        if (module) {
            PyObject *dict = NULL;
            PyObject *key = NULL;
            PyObject *value = NULL;

            dict = PyModule_GetDict(module);
            object = PyDict_GetItemString(dict, "environ");

            if (object) {
                struct passwd *pwent;

                pwent = getpwuid(geteuid());

                if (getenv("USER")) {
#if PY_MAJOR_VERSION >= 3
                    key = PyUnicode_FromString("USER");
                    value = PyUnicode_Decode(pwent->pw_name,
                                             strlen(pwent->pw_name),
                                             Py_FileSystemDefaultEncoding,
                                             "surrogateescape");
#else
                    key = PyString_FromString("USER");
                    value = PyString_FromString(pwent->pw_name);
#endif

                    PyObject_SetItem(object, key, value);

                    Py_DECREF(key);
                    Py_DECREF(value);
                }

                if (getenv("USERNAME")) {
#if PY_MAJOR_VERSION >= 3
                    key = PyUnicode_FromString("USERNAME");
                    value = PyUnicode_Decode(pwent->pw_name,
                                             strlen(pwent->pw_name),
                                             Py_FileSystemDefaultEncoding,
                                             "surrogateescape");
#else
                    key = PyString_FromString("USERNAME");
                    value = PyString_FromString(pwent->pw_name);
#endif

                    PyObject_SetItem(object, key, value);

                    Py_DECREF(key);
                    Py_DECREF(value);
                }

                if (getenv("LOGNAME")) {
#if PY_MAJOR_VERSION >= 3
                    key = PyUnicode_FromString("LOGNAME");
                    value = PyUnicode_Decode(pwent->pw_name,
                                             strlen(pwent->pw_name),
                                             Py_FileSystemDefaultEncoding,
                                             "surrogateescape");
#else
                    key = PyString_FromString("LOGNAME");
                    value = PyString_FromString(pwent->pw_name);
#endif

                    PyObject_SetItem(object, key, value);

                    Py_DECREF(key);
                    Py_DECREF(value);
                }
            }

            Py_DECREF(module);
        }
    }
#endif

    /*
     * If running in daemon process, override HOME environment
     * variable so that is matches the home directory of the
     * user that the process is running as. Need to do this as
     * Apache will inherit HOME from root user or user that ran
     * sudo and started Apache and this would be wrong. Can't
     * update HOME for normal Apache child processes as that
     * would change the expected environment of other Apache
     * modules.
     */

#ifndef WIN32
    if (wsgi_daemon_pool) {
        module = PyImport_ImportModule("os");

        if (module) {
            PyObject *dict = NULL;
            PyObject *key = NULL;
            PyObject *value = NULL;

            dict = PyModule_GetDict(module);
            object = PyDict_GetItemString(dict, "environ");

            if (object) {
                struct passwd *pwent;

                pwent = getpwuid(geteuid());
#if PY_MAJOR_VERSION >= 3
                key = PyUnicode_FromString("HOME");
                value = PyUnicode_Decode(pwent->pw_dir, strlen(pwent->pw_dir),
                                         Py_FileSystemDefaultEncoding,
                                         "surrogateescape");
#else
                key = PyString_FromString("HOME");
                value = PyString_FromString(pwent->pw_dir);
#endif

                PyObject_SetItem(object, key, value);

                Py_DECREF(key);
                Py_DECREF(value);
            }

            Py_DECREF(module);
        }
    }
#endif

    /*
     * Explicitly override the PYTHON_EGG_CACHE variable if it
     * was defined by Apache configuration. For embedded processes
     * this would have been done by using WSGIPythonEggs directive.
     * For daemon processes the 'python-eggs' option to the
     * WSGIDaemonProcess directive would have needed to be used.
     */

    if (!wsgi_daemon_pool)
        wsgi_python_eggs = wsgi_server_config->python_eggs;

    if (wsgi_python_eggs) {
        module = PyImport_ImportModule("os");

        if (module) {
            PyObject *dict = NULL;
            PyObject *key = NULL;
            PyObject *value = NULL;

            dict = PyModule_GetDict(module);
            object = PyDict_GetItemString(dict, "environ");

            if (object) {
#if PY_MAJOR_VERSION >= 3
                key = PyUnicode_FromString("PYTHON_EGG_CACHE");
                value = PyUnicode_Decode(wsgi_python_eggs,
                                         strlen(wsgi_python_eggs),
                                         Py_FileSystemDefaultEncoding,
                                         "surrogateescape");
#else
                key = PyString_FromString("PYTHON_EGG_CACHE");
                value = PyString_FromString(wsgi_python_eggs);
#endif

                PyObject_SetItem(object, key, value);

                Py_DECREF(key);
                Py_DECREF(value);
            }

            Py_DECREF(module);
        }
    }

    /*
     * Install user defined Python module search path. This is
     * added using site.addsitedir() so that any Python .pth
     * files are opened and additional directories so defined
     * are added to default Python search path as well. This
     * allows virtual Python environments to work. Note that
     * site.addsitedir() adds new directories at the end of
     * sys.path when they really need to be added in order at
     * the start. We therefore need to do a fiddle and shift
     * any newly added directories to the start of sys.path.
     */

    if (!wsgi_daemon_pool)
        wsgi_python_path = wsgi_server_config->python_path;

    if (wsgi_python_path) {
        PyObject *path = NULL;

        module = PyImport_ImportModule("site");
        path = PySys_GetObject("path");

        if (module && path) {
            PyObject *dict = NULL;

            PyObject *old = NULL;
            PyObject *new = NULL;
            PyObject *tmp = NULL;

            PyObject *item = NULL;

            int i = 0;

            old = PyList_New(0);
            new = PyList_New(0);
            tmp = PyList_New(0);

            for (i=0; i<PyList_Size(path); i++)
                PyList_Append(old, PyList_GetItem(path, i));

            dict = PyModule_GetDict(module);
            object = PyDict_GetItemString(dict, "addsitedir");

            if (object) {
                const char *start;
                const char *end;
                const char *value;

                PyObject *item;
                PyObject *args;

                PyObject *result = NULL;

                Py_INCREF(object);

                start = wsgi_python_path;
                end = strchr(start, DELIM);

                if (end) {
#if PY_MAJOR_VERSION >= 3
                    item = PyUnicode_Decode(start, end-start,
                                            Py_FileSystemDefaultEncoding,
                                            "surrogateescape");
#else
                    item = PyString_FromStringAndSize(start, end-start);
#endif
                    start = end+1;

                    value = PyString_AsString(item);

                    Py_BEGIN_ALLOW_THREADS
                    ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0), wsgi_server,
                                 "mod_wsgi (pid=%d): Adding '%s' to "
                                 "path.", getpid(), value);
                    Py_END_ALLOW_THREADS

                    args = Py_BuildValue("(O)", item);
                    result = PyEval_CallObject(object, args);

                    if (!result) {
                        Py_BEGIN_ALLOW_THREADS
                        ap_log_error(APLOG_MARK, WSGI_LOG_ERR(0), wsgi_server,
                                     "mod_wsgi (pid=%d): Call to "
                                     "'site.addsitedir()' failed for '%s', "
                                     "stopping.", getpid(), value);
                        Py_END_ALLOW_THREADS
                    }

                    Py_XDECREF(result);
                    Py_DECREF(item);
                    Py_DECREF(args);

                    end = strchr(start, DELIM);

                    while (result && end) {
#if PY_MAJOR_VERSION >= 3
                        item = PyUnicode_Decode(start, end-start,
                                                Py_FileSystemDefaultEncoding,
                                                "surrogateescape");
#else
                        item = PyString_FromStringAndSize(start, end-start);
#endif
                        start = end+1;

                        value = PyString_AsString(item);

                        Py_BEGIN_ALLOW_THREADS
                        ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0), wsgi_server,
                                     "mod_wsgi (pid=%d): Adding '%s' to "
                                     "path.", getpid(), value);
                        Py_END_ALLOW_THREADS

                        args = Py_BuildValue("(O)", item);
                        result = PyEval_CallObject(object, args);

                        if (!result) {
                            Py_BEGIN_ALLOW_THREADS
                            ap_log_error(APLOG_MARK, WSGI_LOG_ERR(0),
                                         wsgi_server, "mod_wsgi (pid=%d): "
                                         "Call to 'site.addsitedir()' failed "
                                         "for '%s', stopping.",
                                         getpid(), value);
                            Py_END_ALLOW_THREADS
                        }

                        Py_XDECREF(result);
                        Py_DECREF(item);
                        Py_DECREF(args);

                        end = strchr(start, DELIM);
                    }
                }

                Py_BEGIN_ALLOW_THREADS
                ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0), wsgi_server,
                             "mod_wsgi (pid=%d): Adding '%s' to "
                             "path.", getpid(), start);
                Py_END_ALLOW_THREADS

                args = Py_BuildValue("(s)", start);
                result = PyEval_CallObject(object, args);

                if (!result) {
                    Py_BEGIN_ALLOW_THREADS
                    ap_log_error(APLOG_MARK, WSGI_LOG_ERR(0), wsgi_server,
                                 "mod_wsgi (pid=%d): Call to "
                                 "'site.addsitedir()' failed for '%s'.",
                                 getpid(), start);
                    Py_END_ALLOW_THREADS
                }

                Py_XDECREF(result);
                Py_DECREF(args);

                Py_DECREF(object);
            }
            else {
                Py_BEGIN_ALLOW_THREADS
                ap_log_error(APLOG_MARK, WSGI_LOG_ERR(0), wsgi_server,
                             "mod_wsgi (pid=%d): Unable to locate "
                             "'site.addsitedir()'.", getpid());
                Py_END_ALLOW_THREADS
            }

            for (i=0; i<PyList_Size(path); i++)
                PyList_Append(tmp, PyList_GetItem(path, i));

            for (i=0; i<PyList_Size(tmp); i++) {
                item = PyList_GetItem(tmp, i);
                if (!PySequence_Contains(old, item)) {
                    int index = PySequence_Index(path, item);
                    PyList_Append(new, item);
                    if (index != -1)
                        PySequence_DelItem(path, index); 
                }
            }

            PyList_SetSlice(path, 0, 0, new);

            Py_DECREF(old);
            Py_DECREF(new);
            Py_DECREF(tmp);
        }
        else {
            if (!module) {
                Py_BEGIN_ALLOW_THREADS
                ap_log_error(APLOG_MARK, WSGI_LOG_ERR(0), wsgi_server,
                             "mod_wsgi (pid=%d): Unable to import 'site' "
                             "module.", getpid());
                Py_END_ALLOW_THREADS
            }

            if (!path) {
                Py_BEGIN_ALLOW_THREADS
                ap_log_error(APLOG_MARK, WSGI_LOG_ERR(0), wsgi_server,
                             "mod_wsgi (pid=%d): Lookup for 'sys.path' "
                             "failed.", getpid());
                Py_END_ALLOW_THREADS
            }
        }

        Py_XDECREF(module);
    }

    /*
     * Create 'mod_wsgi' Python module. We first try and import an
     * external Python module of the same name. The intent is
     * that this external module would provide optional features
     * implementable using pure Python code. Don't want to
     * include them in the main Apache mod_wsgi package as that
     * complicates that package and also wouldn't allow them to
     * be released to a separate schedule. It is easier for
     * people to replace Python modules package with a new
     * version than it is to replace Apache module package.
     */

    module = PyImport_ImportModule("mod_wsgi");

    if (!module) {
        PyObject *modules = NULL;

        modules = PyImport_GetModuleDict();
        module = PyDict_GetItemString(modules, "mod_wsgi");

        if (module) {
            PyErr_Print();

            PyDict_DelItemString(modules, "mod_wsgi");
        }

        PyErr_Clear();

        module = PyImport_AddModule("mod_wsgi");

        Py_INCREF(module);
    }
    else if (!*name) {
        Py_BEGIN_ALLOW_THREADS
        ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0), wsgi_server,
                     "mod_wsgi (pid=%d): Imported 'mod_wsgi'.",
                     getpid());
        Py_END_ALLOW_THREADS
    }

    /*
     * Add Apache module version information to the Python
     * 'mod_wsgi' module.
     */

    PyModule_AddObject(module, "version", Py_BuildValue("(ii)",
                       MOD_WSGI_MAJORVERSION_NUMBER,
                       MOD_WSGI_MINORVERSION_NUMBER));

    /*
     * Add information about process group and application
     * group to the Python 'mod_wsgi' module.
     */

#if PY_MAJOR_VERSION >= 3
    PyModule_AddObject(module, "process_group",
                       PyUnicode_DecodeLatin1(wsgi_daemon_group,
                       strlen(wsgi_daemon_group), NULL));
    PyModule_AddObject(module, "application_group",
                       PyUnicode_DecodeLatin1(name, strlen(name), NULL));
#else
    PyModule_AddObject(module, "process_group",
                       PyString_FromString(wsgi_daemon_group));
    PyModule_AddObject(module, "application_group",
                       PyString_FromString(name));
#endif

    Py_DECREF(module);

    /*
     * Create 'apache' Python module. If this is not a daemon
     * process and it is the first interpreter created by
     * Python, we first try and import an external Python module
     * of the same name. The intent is that this external module
     * would provide the SWIG bindings for the internal Apache
     * APIs. Only support use of such bindings in the first
     * interpreter created due to threading issues in SWIG
     * generated.
     */

    module = NULL;

    if (!wsgi_daemon_pool) {
        module = PyImport_ImportModule("apache");

        if (!module) {
            PyObject *modules = NULL;

            modules = PyImport_GetModuleDict();
            module = PyDict_GetItemString(modules, "apache");

            if (module) {
                Py_BEGIN_ALLOW_THREADS
                ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0), wsgi_server,
                             "mod_wsgi (pid=%d): Unable to import "
                             "'apache' extension module.", getpid());
                Py_END_ALLOW_THREADS

                PyErr_Print();

                PyDict_DelItemString(modules, "apache");

                module = NULL;
            }

            PyErr_Clear();
        }
        else {
            Py_BEGIN_ALLOW_THREADS
            ap_log_error(APLOG_MARK, WSGI_LOG_INFO(0), wsgi_server,
                         "mod_wsgi (pid=%d): Imported 'apache'.",
                         getpid());
            Py_END_ALLOW_THREADS
        }
    }

    if (!module) {
        module = PyImport_AddModule("apache");

        Py_INCREF(module);
    }

    /*
     * Add Apache version information to the Python 'apache'
     * module.
     */

    PyModule_AddObject(module, "version", Py_BuildValue("(ii)",
                       AP_SERVER_MAJORVERSION_NUMBER,
                       AP_SERVER_MINORVERSION_NUMBER));

    Py_DECREF(module);

    /*
     * Restore previous thread state. Only need to do
     * this where had to create a new interpreter. This
     * is basically anything except the first Python
     * interpreter instance. We need to restore it in
     * these cases as came into the function holding the
     * simplified GIL state for this thread but creating
     * the interpreter has resulted in a new thread
     * state object being created bound to the newly
     * created interpreter. In doing this though we want
     * to cache the thread state object which has been
     * created when interpreter is created. This is so
     * it can be reused later ensuring that thread local
     * data persists between requests.
     */

    if (self->owner) {
#if APR_HAS_THREADS
        int thread_id = 0;
        int *thread_handle = NULL;

        self->tstate_table = apr_hash_make(wsgi_server->process->pool);

        apr_threadkey_private_get((void**)&thread_handle, wsgi_thread_key);

        if (!thread_handle) {
            thread_id = wsgi_thread_count++;
            thread_handle = (int*)apr_pmemdup(wsgi_server->process->pool,
                                              &thread_id, sizeof(thread_id));
            apr_threadkey_private_set(thread_handle, wsgi_thread_key);
        }
        else {
            thread_id = *thread_handle;
        }

        if (wsgi_server_config->verbose_debugging) {
            ap_log_error(APLOG_MARK, WSGI_LOG_DEBUG(0), wsgi_server,
                         "mod_wsgi (pid=%d): Bind thread state for "
                         "thread %d against interpreter '%s'.", getpid(),
                         thread_id, self->name);
        }

        apr_hash_set(self->tstate_table, thread_handle,
                     sizeof(*thread_handle), tstate);

        PyThreadState_Swap(save_tstate);
#else
        self->tstate = tstate;
        PyThreadState_Swap(save_tstate);
#endif
    }

    return self;
}

Project: mod_wsgi
File: mod_wsgi.c

static ShutdownInterpreterObject *newShutdownInterpreterObject(
        PyObject *wrapped)
{
    ShutdownInterpreterObject *self = NULL;

    self = PyObject_New(ShutdownInterpreterObject, &ShutdownInterpreter_Type);
    if (self == NULL)
        return NULL;

    Py_INCREF(wrapped);
    self->wrapped = wrapped;

    return self;
}

Project: mod_wsgi
File: mod_wsgi.c

static void ShutdownInterpreter_dealloc(ShutdownInterpreterObject *self)
{
    Py_DECREF(self->wrapped);
}

Project: mod_wsgi
File: mod_wsgi.c

static void wsgi_setup_access(WSGIDaemonProcess *daemon)
{
    /* Setup the umask for the effective user. */

    if (daemon->group->umask != -1)
        umask(daemon->group->umask);

    /* Change to chroot environment. */

    if (daemon->group->root) {
        if (chroot(daemon->group->root) == -1) {
            ap_log_error(APLOG_MARK, WSGI_LOG_ALERT(errno), wsgi_server,
                         "mod_wsgi (pid=%d): Unable to change root "
                         "directory to '%s'.", getpid(), daemon->group->root);
        }
    }

    /* Setup the working directory.*/

    if (daemon->group->home) {
        if (chdir(daemon->group->home) == -1) {
            ap_log_error(APLOG_MARK, WSGI_LOG_ALERT(errno), wsgi_server,
                         "mod_wsgi (pid=%d): Unable to change working "
                         "directory to '%s'.", getpid(), daemon->group->home);
        }
    }
    else if (geteuid()) {
        struct passwd *pwent;

        pwent = getpwuid(geteuid());

        if (pwent) {
            if (chdir(pwent->pw_dir) == -1) {
                ap_log_error(APLOG_MARK, WSGI_LOG_ALERT(errno), wsgi_server,
                             "mod_wsgi (pid=%d): Unable to change working "
                             "directory to '%s'.", getpid(), pwent->pw_dir);
            }
        }
        else {
            ap_log_error(APLOG_MARK, WSGI_LOG_ALERT(errno), wsgi_server,
                         "mod_wsgi (pid=%d): Unable to determine home "
                         "directory for uid=%ld.", getpid(), (long)geteuid());
        }
    }
    else {
        struct passwd *pwent;

        pwent = getpwuid(daemon->group->uid);

        if (pwent) {
            if (chdir(pwent->pw_dir) == -1) {
                ap_log_error(APLOG_MARK, WSGI_LOG_ALERT(errno), wsgi_server,
                             "mod_wsgi (pid=%d): Unable to change working "
                             "directory to '%s'.", getpid(), pwent->pw_dir);
            }
        }
        else {
            ap_log_error(APLOG_MARK, WSGI_LOG_ALERT(errno), wsgi_server,
                         "mod_wsgi (pid=%d): Unable to determine home "
                         "directory for uid=%ld.", getpid(),
                         (long)daemon->group->uid);
        }
    }

    /* Don't bother switch user/group if not root. */

    if (geteuid())
        return;

    /* Setup the daemon process real and effective group. */

    if (setgid(daemon->group->gid) == -1) {
        ap_log_error(APLOG_MARK, WSGI_LOG_ALERT(errno), wsgi_server,
                     "mod_wsgi (pid=%d): Unable to set group id to gid=%u.",
                     getpid(), (unsigned)daemon->group->gid);
    }
    else {
        if (daemon->group->groups) {
            if (setgroups(daemon->group->groups_count,
                          daemon->group->groups) == -1) {
                ap_log_error(APLOG_MARK, WSGI_LOG_ALERT(errno),
                             wsgi_server, "mod_wsgi (pid=%d): Unable "
                             "to set supplementary groups for uname=%s "
                             "of '%s'.", getpid(), daemon->group->user,
                             daemon->group->groups_list);
            }
        }
        else if (initgroups(daemon->group->user, daemon->group->gid) == -1) {
            ap_log_error(APLOG_MARK, WSGI_LOG_ALERT(errno),
                         wsgi_server, "mod_wsgi (pid=%d): Unable "
                         "to set groups for uname=%s and gid=%u.", getpid(),
                         daemon->group->user, (unsigned)daemon->group->gid);
        }
    }

    /* Setup the daemon process real and effective user. */

    if (setuid(daemon->group->uid) == -1) {
        ap_log_error(APLOG_MARK, WSGI_LOG_ALERT(errno), wsgi_server,
                     "mod_wsgi (pid=%d): Unable to change to uid=%ld.",
                     getpid(), (long)daemon->group->uid);

        /*
         * On true UNIX systems this should always succeed at
         * this point. With certain Linux kernel versions though
         * we can get back EAGAIN where the target user had
         * reached their process limit. In that case will be left
         * running as wrong user. Just exit on all failures to be
         * safe. Don't die immediately to avoid a fork bomb.
         */

        sleep(20);

        exit(-1);
    }

    /*
     * Linux prevents generation of core dumps after setuid()
     * has been used. Attempt to reenable ability to dump core
     * so that the CoreDumpDirectory directive still works.
     */

#if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
    /* This applies to Linux 2.4 and later. */
    if (ap_coredumpdir_configured) {
        if (prctl(PR_SET_DUMPABLE, 1)) {
            ap_log_error(APLOG_MARK, WSGI_LOG_ALERT(errno), wsgi_server,
                    "mod_wsgi (pid=%d): Set dumpable failed. This child "
                    "will not coredump after software errors.", getpid());
        }
    }
#endif
}