1 /*
2 * Copyright (c) 2016-present, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 */
9
10 /**
11 * Helper functions for fuzzing.
12 */
13
14 #ifndef FUZZ_HELPERS_H
15 #define FUZZ_HELPERS_H
16
17 #include "fuzz.h"
18 #include "xxhash.h"
19 #include "zstd.h"
20 #include <stdint.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23
24 #ifdef __cplusplus
25 extern "C" {
26 #endif
27
28 #define MIN(a, b) ((a) < (b) ? (a) : (b))
29 #define MAX(a, b) ((a) > (b) ? (a) : (b))
30
31 #define FUZZ_QUOTE_IMPL(str) #str
32 #define FUZZ_QUOTE(str) FUZZ_QUOTE_IMPL(str)
33
34 /**
35 * Asserts for fuzzing that are always enabled.
36 */
37 #define FUZZ_ASSERT_MSG(cond, msg) \
38 ((cond) ? (void)0 \
39 : (fprintf(stderr, "%s: %u: Assertion: `%s' failed. %s\n", __FILE__, \
40 __LINE__, FUZZ_QUOTE(cond), (msg)), \
41 abort()))
42 #define FUZZ_ASSERT(cond) FUZZ_ASSERT_MSG((cond), "");
43 #define FUZZ_ZASSERT(code) \
44 FUZZ_ASSERT_MSG(!ZSTD_isError(code), ZSTD_getErrorName(code))
45
46 #if defined(__GNUC__)
47 #define FUZZ_STATIC static __inline __attribute__((unused))
48 #elif defined(__cplusplus) || \
49 (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
50 #define FUZZ_STATIC static inline
51 #elif defined(_MSC_VER)
52 #define FUZZ_STATIC static __inline
53 #else
54 #define FUZZ_STATIC static
55 #endif
56
57 /**
58 * Deterministically constructs a seed based on the fuzz input.
59 * Consumes up to the first FUZZ_RNG_SEED_SIZE bytes of the input.
60 */
FUZZ_seed(uint8_t const ** src,size_t * size)61 FUZZ_STATIC uint32_t FUZZ_seed(uint8_t const **src, size_t* size) {
62 uint8_t const *data = *src;
63 size_t const toHash = MIN(FUZZ_RNG_SEED_SIZE, *size);
64 *size -= toHash;
65 *src += toHash;
66 return XXH32(data, toHash, 0);
67 }
68
69 #define FUZZ_rotl32(x, r) (((x) << (r)) | ((x) >> (32 - (r))))
70
FUZZ_rand(uint32_t * state)71 FUZZ_STATIC uint32_t FUZZ_rand(uint32_t *state) {
72 static const uint32_t prime1 = 2654435761U;
73 static const uint32_t prime2 = 2246822519U;
74 uint32_t rand32 = *state;
75 rand32 *= prime1;
76 rand32 += prime2;
77 rand32 = FUZZ_rotl32(rand32, 13);
78 *state = rand32;
79 return rand32 >> 5;
80 }
81
82 /* Returns a random numer in the range [min, max]. */
FUZZ_rand32(uint32_t * state,uint32_t min,uint32_t max)83 FUZZ_STATIC uint32_t FUZZ_rand32(uint32_t *state, uint32_t min, uint32_t max) {
84 uint32_t random = FUZZ_rand(state);
85 return min + (random % (max - min + 1));
86 }
87
88 #ifdef __cplusplus
89 }
90 #endif
91
92 #endif
93