ganglia/ganglia-gmond-python2to3.patch

diff --git a/gmond/modules/python/mod_python.c b/gmond/modules/python/mod_python.c
index ed5a401..484429e 100644
--- a/gmond/modules/python/mod_python.c
+++ b/gmond/modules/python/mod_python.c
@@ -29,6 +29,10 @@
 *
 * Author: Brad Nicholes (bnicholes novell.com)
 *         Jon Carey (jcarey novell.com)
+*
+* Modified for Python3 support, based on code at https://docs.python.org/3.5/howto/cporting.html
+* Tom Crane (T.Crane@rhul.ac.uk), June 2024.
+*
 ******************************************************************************/
 
 #include <Python.h>
@@ -51,12 +55,23 @@
 /*
  * Backward compatibility for 2.1 to 2.4
  */
+#if PY_MAJOR_VERSION < 3
 #if PY_MINOR_VERSION < 5
 #define Py_ssize_t int
 #if PY_MINOR_VERSION < 3
 #define PyInt_AsUnsignedLongMask PyInt_AsLong
 #endif
 #endif
+#endif
+
+#if PY_MAJOR_VERSION >= 3
+# define PyInt_AsLong(x) (PyLong_AsLong((x)))
+# define PyInt_Check(x) (PyLong_Check((x)))
+# define PyString_Check(x) (PyUnicode_Check((x)))
+# define PyString_AsString(x) (PyUnicode_AsUTF8((x)))
+# define PyInt_AsUnsignedLongMask(x) (PyLong_AsUnsignedLongMask((x)))
+# define PyString_FromString(x) (PyUnicode_FromString((x)))
+#endif
 
 /*
  * Declare ourselves so the configuration routines can find and know us.
@@ -540,7 +555,57 @@ static PyMethodDef GangliaMethods[] = {
     {NULL, NULL, 0, NULL}
 };
 
+struct module_state {
+  PyObject *error;
+};
+
+#if PY_MAJOR_VERSION >= 3
+#define GETSTATE(m) ((struct module_state*)PyModule_GetState(m))
+#else
+#define GETSTATE(m) (&_state)
+static struct module_state _state;
+#endif
+
+static PyObject *
+error_out(PyObject *m) {
+  struct module_state *st = GETSTATE(m);
+  PyErr_SetString(st->error, "something bad happened");
+  return NULL;
+}
+
+#if PY_MAJOR_VERSION >= 3
+
+static int ganglia_traverse(PyObject *m, visitproc visit, void *arg) {
+  Py_VISIT(GETSTATE(m)->error);
+  return 0;
+}
+
+static int ganglia_clear(PyObject *m) {
+  Py_CLEAR(GETSTATE(m)->error);
+  return 0;
+}
+
+
+static struct PyModuleDef moduledef = {
+  PyModuleDef_HEAD_INIT,
+  "ganglia",
+  NULL,
+  sizeof(struct module_state),
+  GangliaMethods,
+  NULL,
+  ganglia_traverse,
+  ganglia_clear,
+  NULL
+};
+
+#define INITERROR return NULL
+
+PyMODINIT_FUNC PyInit_metric_init(apr_pool_t *p)
+#else
+#define INITERROR return
+
 static int pyth_metric_init (apr_pool_t *p)
+#endif
 {
     DIR *dp;
     struct dirent *entry;
@@ -563,29 +628,41 @@ static int pyth_metric_init (apr_pool_t *p)
 
     if (!path) {
         err_msg("[PYTHON] Missing python module path.\n");
-        return -1;
+        INITERROR;
     }
 
     if (access(path, F_OK))
     {
         /* 'path' does not exist */
         err_msg("[PYTHON] Can't open the python module path %s.\n", path);
-        return -1;
+        INITERROR;
     }
 
     if (access(path, R_OK))
     {
         /* Don't have read access to 'path' */
         err_msg("[PYTHON] Can't read from the python module path %s.\n", path);
-        return -1;
+        INITERROR;
     }
 
     /* Init Python environment */
 
     /* Set up the python path to be able to load module from our module path */
     Py_Initialize();
-    Py_InitModule("ganglia", GangliaMethods);
+#if PY_MAJOR_VERSION >= 3
+    PyObject *module = PyModule_Create(&moduledef);
+#else
+    PyObject *module = Py_InitModule("ganglia", GangliaMethods);
+#endif
+    if (module == NULL)
+        INITERROR;
+    struct module_state *st = GETSTATE(module);
 
+    st->error = PyErr_NewException("ganglia.Error", NULL, NULL);
+    if (st->error == NULL) {
+        Py_DECREF(module);
+        INITERROR;
+    }
     PyObject *sys_path = PySys_GetObject("path");
     PyObject *addpath = PyString_FromString(path);
     PyList_Append(sys_path, addpath);
@@ -598,7 +675,7 @@ static int pyth_metric_init (apr_pool_t *p)
         /* Error: Cannot open the directory - Shouldn't happen */
         /* Log? */
         err_msg("[PYTHON] Can't open the python module path %s.\n", path);
-        return -1;
+        INITERROR;
     }
 
     i = 0;
@@ -712,7 +789,11 @@ static int pyth_metric_init (apr_pool_t *p)
     memset (mi, 0, sizeof(*mi));
 
     python_module.metrics_info = (Ganglia_25metric *)metric_info->elts;
+#if PY_MAJOR_VERSION >= 3
+    return module;
+#else
     return 0;
+#endif
 }
 
 static apr_status_t pyth_metric_cleanup ( void *data)
@@ -832,7 +913,11 @@ static g_val_t pyth_metric_handler( int metric_index )
 mmodule python_module =
 {
     STD_MMODULE_STUFF,
+#if PY_MAJOR_VERSION >= 3
+    (int (*)(apr_pool_t *))PyInit_metric_init,
+#else
     pyth_metric_init,
+#endif
     NULL,
     NULL, /* defined dynamically */
     pyth_metric_handler,