modlang-134

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@14898 d0543943-73ff-0310-b7d9-9358b9ac24b2

diff --git a/src/mod/languages/mod_python/mod_python.c b/src/mod/languages/mod_python/mod_python.c
index ffc867a30c7ec5c77979b8409ae05ba9726b82da..2581d992f5b2f76fe887b51c931cbcf0835e7ca1 100644 (file)
--- a/src/mod/languages/mod_python/mod_python.c
+++ b/src/mod/languages/mod_python/mod_python.c
@@ -48,6 +48,7 @@ PyThreadState *mainThreadState = NULL;
 
 void init_freeswitch(void);
 int py_thread(const char *text);
+static void set_max_recursion_depth(void);
 static switch_api_interface_t python_run_interface;
 
 SWITCH_MODULE_LOAD_FUNCTION(mod_python_load);
@@ -292,6 +293,36 @@ static switch_status_t do_config(void)
        return SWITCH_STATUS_SUCCESS;
 }
 
+
+/**
+ * As freeswitch runs with a smaller than normal stack size (240K instead of the usual value .. 1 or 2 MB),
+ * we must decrease the default python recursion limit accordingly.  Otherwise, python can easily blow
+ * up the stack and the whole switch crashes.  See modlang-134
+ */
+static void set_max_recursion_depth(void) {
+
+       // assume that a stack frame is approximately 1K, so divide thread stack size (eg, 240K) by
+       // 1K to get the approx number of stack frames we can hold before blowing up.
+       int newMaxRecursionDepth = SWITCH_THREAD_STACKSIZE / 1024;
+       
+       PyObject *sysModule = PyImport_ImportModule("sys");
+       PyObject *setRecursionLimit = PyObject_GetAttrString(sysModule, "setrecursionlimit");
+       PyObject *recLimit = Py_BuildValue("(i)",newMaxRecursionDepth);
+       PyObject *setrecursion_result = PyEval_CallObjectWithKeywords(setRecursionLimit, recLimit, (PyObject *) NULL);
+       if (setrecursion_result) {
+               switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "Set python recursion limit to %d\n", newMaxRecursionDepth);
+       }
+       else {
+               switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Failed to set recursion limit to %d\n", newMaxRecursionDepth);
+               PyErr_Print();
+               PyErr_Clear();
+               PyRun_SimpleString("python_makes_sense");
+               PyGC_Collect();
+       }
+
+
+}
+
 SWITCH_STANDARD_APP(python_function)
 {
        eval_some_python("handler", (char *) data, session, NULL, NULL, NULL, NULL);
@@ -406,6 +437,9 @@ SWITCH_MODULE_LOAD_FUNCTION(mod_python_load)
                // to create new threadstates, and will be needed for shutdown
                mainThreadState = PyThreadState_Get();
 
+               // set the maximum recursion depth
+               set_max_recursion_depth();
+
                // swap out threadstate since the call threads will create
                // their own and swap in their threadstate
                PyThreadState_Swap(NULL);