python plugin: Don't shut down the Python interpreter as long as there might be callb...

diff --git a/src/python.c b/src/python.c
index 94058421fbe053874befb6190d9c9b7cd9bed723..1a7359cd526a5d9a5e7e725dc77671d88cf6d29d 100644 (file)
--- a/src/python.c
+++ b/src/python.c
@@ -236,14 +236,23 @@ static cpy_callback_t *cpy_config_callbacks;
 static cpy_callback_t *cpy_init_callbacks;
 static cpy_callback_t *cpy_shutdown_callbacks;
 
+/* Make sure to hold the GIL while modifying these. */
+static int cpy_shutdown_triggered = 0;
+static int cpy_num_callbacks = 0;
+
 static void cpy_destroy_user_data(void *data) {
        cpy_callback_t *c = data;
        free(c->name);
        CPY_LOCK_THREADS
        Py_DECREF(c->callback);
        Py_XDECREF(c->data);
-       CPY_RELEASE_THREADS
        free(c);
+       --cpy_num_callbacks;
+       if (!cpy_num_callbacks && cpy_shutdown_triggered) {
+               Py_Finalize();
+               return;
+       }
+       CPY_RELEASE_THREADS
 }
 
 /* You must hold the GIL to call this function!
@@ -565,6 +574,7 @@ static PyObject *cpy_register_generic(cpy_callback_t **list_head, PyObject *args
        c->callback = callback;
        c->data = data;
        c->next = *list_head;
+       ++cpy_num_callbacks;
        *list_head = c;
        Py_XDECREF(mod);
        PyMem_Free(name);
@@ -661,6 +671,7 @@ static PyObject *cpy_register_generic_userdata(void *reg, void *handler, PyObjec
        };
 
        register_function(buf, handler, &user_data);
+       ++cpy_num_callbacks;
        return cpy_string_to_unicode_or_bytes(buf);
 }
 
@@ -700,6 +711,7 @@ static PyObject *cpy_register_read(PyObject *self, PyObject *args, PyObject *kwd
 
        plugin_register_complex_read(/* group = */ "python", buf,
                        cpy_read_callback, DOUBLE_TO_CDTIME_T (interval), &user_data);
+       ++cpy_num_callbacks;
        return cpy_string_to_unicode_or_bytes(buf);
 }
 
@@ -913,9 +925,7 @@ static PyMethodDef cpy_methods[] = {
 static int cpy_shutdown(void) {
        PyObject *ret;
 
-       /* This can happen if the module was loaded but not configured. */
-       if (state != NULL)
-               PyEval_RestoreThread(state);
+       PyEval_RestoreThread(state);
 
        for (cpy_callback_t *c = cpy_shutdown_callbacks; c; c = c->next) {
                ret = PyObject_CallFunctionObjArgs(c->callback, c->data, (void *) 0); /* New reference. */
@@ -929,8 +939,11 @@ static int cpy_shutdown(void) {
        cpy_unregister_list(&cpy_config_callbacks);
        cpy_unregister_list(&cpy_init_callbacks);
        cpy_unregister_list(&cpy_shutdown_callbacks);
+       cpy_shutdown_triggered = 1;
+
+       if (!cpy_num_callbacks)
+               Py_Finalize();
 
-       Py_Finalize();
        return 0;
 }
 
@@ -983,6 +996,7 @@ static int cpy_init(void) {
        if (!Py_IsInitialized()) {
                WARNING("python: Plugin loaded but not configured.");
                plugin_unregister_shutdown("python");
+               Py_Finalize();
                return 0;
        }
        PyEval_InitThreads();