annotate contrib/fuzz/revlog.cc @ 41309:afc33a5705b9

fuzz: don't allow enormous revlog inputs either

I'm about to make the fuzzer do more, and without this it was getting
enthusiastic about large (and therefore slow) inputs that I don't
think buy us much.

Differential Revision: https://phab.mercurial-scm.org/D5640

#include <Python.h>
#include <assert.h>
#include <stdlib.h>
#include <unistd.h>

#include <string>

#include "pyutil.h"

extern "C" {

static PyCodeObject *code;

extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv)
{
	contrib::initpy(*argv[0]);
	code = (PyCodeObject *)Py_CompileString(R"py(
from parsers import parse_index2
for inline in (True, False):
    try:
        index, cache = parse_index2(data, inline)
    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 60k, since we'll just bog
	// down and not accomplish much.
	if (Size > 60000) {
		return 0;
	}
	PyObject *text =
	    PyBytes_FromStringAndSize((const char *)Data, (Py_ssize_t)Size);
	PyObject *locals = PyDict_New();
	PyDict_SetItemString(locals, "data", text);
	PyObject *res = PyEval_EvalCode(code, contrib::pyglobals(), locals);
	if (!res) {
		PyErr_Print();
	}
	Py_XDECREF(res);
	Py_DECREF(locals);
	Py_DECREF(text);
	return 0; // Non-zero return values are reserved for future use.
}
}