diff contrib/fuzz/pyutil.cc @ 41013:ef103c96ed33

fuzz: extract Python initialization to utility package

Avoids code duplication between fuzzers of parsers.so.

Differential Revision: https://phab.mercurial-scm.org/D5461

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/contrib/fuzz/pyutil.cc	Wed Dec 19 21:57:23 2018 -0500
@@ -0,0 +1,49 @@
+#include "pyutil.h"
+
+#include <string>
+
+namespace contrib
+{
+
+static char cpypath[8192] = "\0";
+
+static PyObject *mainmod;
+static PyObject *globals;
+
+/* TODO: use Python 3 for this fuzzing? */
+PyMODINIT_FUNC initparsers(void);
+
+void initpy(const char *cselfpath)
+{
+	const std::string subdir = "/sanpy/lib/python2.7";
+	/* HACK ALERT: we need a full Python installation built without
+	   pymalloc and with ASAN, so we dump one in
+	   $OUT/sanpy/lib/python2.7. This helps us wire that up. */
+	std::string selfpath(cselfpath);
+	std::string pypath;
+	auto pos = selfpath.rfind("/");
+	if (pos == std::string::npos) {
+		char wd[8192];
+		getcwd(wd, 8192);
+		pypath = std::string(wd) + subdir;
+	} else {
+		pypath = selfpath.substr(0, pos) + subdir;
+	}
+	strncpy(cpypath, pypath.c_str(), pypath.size());
+	setenv("PYTHONPATH", cpypath, 1);
+	setenv("PYTHONNOUSERSITE", "1", 1);
+	/* prevent Python from looking up users in the fuzz environment */
+	setenv("PYTHONUSERBASE", cpypath, 1);
+	Py_SetPythonHome(cpypath);
+	Py_InitializeEx(0);
+	mainmod = PyImport_AddModule("__main__");
+	globals = PyModule_GetDict(mainmod);
+	initparsers();
+}
+
+PyObject *pyglobals()
+{
+	return globals;
+}
+
+} // namespace contrib