changeset 40373:c3ab0a89331d

fuzz: move many initialization steps into LLVMFuzzerInitialize

Doing this means that things we intentionally leak (eg type objects)
no longer confuse AddressSanitizer, so now we can run the fuzzer MUCH
longer.

Differential Revision: https://phab.mercurial-scm.org/D5154

--- a/contrib/fuzz/manifest.cc	Thu Nov 17 15:51:33 2016 -0800
+++ b/contrib/fuzz/manifest.cc	Thu Oct 18 16:36:10 2018 -0400
@@ -12,6 +12,10 @@
 
 static char cpypath[8192] = "\0";
 
+static PyCodeObject *code;
+static PyObject *mainmod;
+static PyObject *globals;
+
 extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv)
 {
 	const std::string subdir = "/sanpy/lib/python2.7";
@@ -35,20 +39,8 @@
 	setenv("PYTHONUSERBASE", cpypath, 1);
 	Py_SetPythonHome(cpypath);
 	Py_InitializeEx(0);
-	return 0;
-}
-
-int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
-{
 	initparsers();
-	PyObject *mtext =
-	    PyBytes_FromStringAndSize((const char *)Data, (Py_ssize_t)Size);
-	PyObject *mainmod = PyImport_AddModule("__main__");
-	PyObject *globals = PyModule_GetDict(mainmod);
-	PyObject *locals = PyDict_New();
-	PyDict_SetItemString(locals, "mdata", mtext);
-	PyCodeObject *code =
-	    (PyCodeObject *)Py_CompileString(R"py(
+	code = (PyCodeObject *)Py_CompileString(R"py(
 from parsers import lazymanifest
 try:
   lm = lazymanifest(mdata)
@@ -67,13 +59,23 @@
   # to debug failures.
   # print e
 )py",
-	                                     "fuzzer", Py_file_input);
+	                                        "fuzzer", Py_file_input);
+	mainmod = PyImport_AddModule("__main__");
+	globals = PyModule_GetDict(mainmod);
+	return 0;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
+{
+	PyObject *mtext =
+	    PyBytes_FromStringAndSize((const char *)Data, (Py_ssize_t)Size);
+	PyObject *locals = PyDict_New();
+	PyDict_SetItemString(locals, "mdata", mtext);
 	PyObject *res = PyEval_EvalCode(code, globals, locals);
 	if (!res) {
 		PyErr_Print();
 	}
 	Py_XDECREF(res);
-	Py_DECREF(code);
 	Py_DECREF(locals);
 	Py_DECREF(mtext);
 	return 0; // Non-zero return values are reserved for future use.