fuzz: add support for fuzzing under either Python 2 or 3
This was more of a hairball than I hoped, but it appears to work. The hg-py3
branch of my oss-fuzz fork on github has the remaining changes to switch us to
Python 3, but we may as well retain Python 2 fuzzing support for at least a
little while.
Differential Revision: https://phab.mercurial-scm.org/D7592
#include <Python.h>
#include <assert.h>
#include <stdlib.h>
#include <unistd.h>
#include "pyutil.h"
#include <string>
extern "C" {
static PYCODETYPE *code;
extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv)
{
contrib::initpy(*argv[0]);
code = (PYCODETYPE *)Py_CompileString(R"py(
try:
files = mdata.split('\n')
d = parsers.dirs(files)
list(d)
'a' in d
if files:
files[0] in d
except Exception as e:
pass
# uncomment this print if you're editing this Python code
# to debug failures.
# print e
)py",
"fuzzer", Py_file_input);
return 0;
}
int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
{
// Don't allow fuzzer inputs larger than 100k, since we'll just bog
// down and not accomplish much.
if (Size > 100000) {
return 0;
}
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, contrib::pyglobals(), locals);
if (!res) {
PyErr_Print();
}
Py_XDECREF(res);
Py_DECREF(locals);
Py_DECREF(mtext);
return 0; // Non-zero return values are reserved for future use.
}
}