contrib/fuzz/bdiff.cc
author Gregory Szorc <gregory.szorc@gmail.com>
Wed, 04 Apr 2018 14:09:02 -0700
changeset 37415 c2c8962a9465
parent 35670 2b9e2415f5b5
child 38173 fa0ddd5e8fff
permissions -rw-r--r--
simplestore: use a custom store for the simple store repo Before, we used the default store, which was based on fncache and dotencode. After attempting to port tests to work with the simple store, I realized that fncache was more trouble than it is worth. This commit implements a proper store type for the simple repo - one that isn't based off fncache. This causes a number of new test failures because of tests expecting the full fncache store filename encoding. I may extend the store format in a subsequent commit to take the filename encoding parts of fncache that we can take (basically everything except hash encoding, since that isn't reversible). But for now, let's use encoded store. As part of this, we implement proper requirements support for repos created with the simple store. This should have been done from the beginning, as a requirement is needed to lock out clients that don't understand a storage format. A new hghave feature advertising the presence of fncache in repos has been added. Most tests touching the fncache are now conditional on that feature. Other tests have added the optional repo requirement to output. Differential Revision: https://phab.mercurial-scm.org/D3095

/*
 * bdiff.cc - fuzzer harness for bdiff.c
 *
 * Copyright 2018, Google Inc.
 *
 * This software may be used and distributed according to the terms of
 * the GNU General Public License, incorporated herein by reference.
 */
#include <stdlib.h>

extern "C" {
#include "bdiff.h"

int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
{
	if (!Size) {
		return 0;
	}
	// figure out a random point in [0, Size] to split our input.
	size_t split = Data[0] / 255.0 * Size;

	// left input to diff is data[1:split]
	const uint8_t *left = Data + 1;
	// which has len split-1
	size_t left_size = split - 1;
	// right starts at the next byte after left ends
	const uint8_t *right = left + left_size;
	size_t right_size = Size - split;

	struct bdiff_line *a, *b;
	int an = bdiff_splitlines((const char *)left, split - 1, &a);
	int bn = bdiff_splitlines((const char *)right, right_size, &b);
	struct bdiff_hunk l;
	bdiff_diff(a, an, b, bn, &l);
	free(a);
	free(b);
	bdiff_freehunks(l.next);
	return 0; // Non-zero return values are reserved for future use.
}

#ifdef HG_FUZZER_INCLUDE_MAIN
int main(int argc, char **argv)
{
	const char data[] = "asdf";
	return LLVMFuzzerTestOneInput((const uint8_t *)data, 4);
}
#endif

} // extern "C"