1 // Copyright 2021 The Tint Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 #include "fuzzers/tint_regex_fuzzer/cli.h"
16
17 #include <cstring>
18 #include <iostream>
19 #include <limits>
20 #include <sstream>
21 #include <string>
22 #include <utility>
23
24 namespace tint {
25 namespace fuzzers {
26 namespace regex_fuzzer {
27 namespace {
28
29 const char* const kHelpMessage = R"(
30 This is a fuzzer for the Tint compiler that works by mutating a WGSL shader.
31
32 Below is a list of all supported parameters for this fuzzer. You may want to
33 run it with -help=1 to check out libfuzzer parameters.
34
35 -tint_fuzzing_target=
36 Specifies the shading language to target during fuzzing.
37 This must be one or a combination of `wgsl`, `spv`, `hlsl`,
38 `msl` (without `) separated by commas. By default it's
39 `wgsl,msl,hlsl,spv`.
40
41 -tint_help
42 Show this message. Note that there is also a -help=1
43 parameter that will display libfuzzer's help message.
44 )";
45
HasPrefix(const char * str,const char * prefix)46 bool HasPrefix(const char* str, const char* prefix) {
47 return strncmp(str, prefix, strlen(prefix)) == 0;
48 }
49
InvalidParam(const char * param)50 [[noreturn]] void InvalidParam(const char* param) {
51 std::cout << "Invalid value for " << param << std::endl;
52 std::cout << kHelpMessage << std::endl;
53 exit(1);
54 }
55
ParseFuzzingTarget(const char * value,FuzzingTarget * out)56 bool ParseFuzzingTarget(const char* value, FuzzingTarget* out) {
57 if (!strcmp(value, "wgsl")) {
58 *out = FuzzingTarget::kWgsl;
59 } else if (!strcmp(value, "spv")) {
60 *out = FuzzingTarget::kSpv;
61 } else if (!strcmp(value, "msl")) {
62 *out = FuzzingTarget::kMsl;
63 } else if (!strcmp(value, "hlsl")) {
64 *out = FuzzingTarget::kHlsl;
65 } else {
66 return false;
67 }
68 return true;
69 }
70
71 } // namespace
72
ParseCliParams(int * argc,char ** argv)73 CliParams ParseCliParams(int* argc, char** argv) {
74 CliParams cli_params;
75 auto help = false;
76
77 for (int i = *argc - 1; i > 0; --i) {
78 auto param = argv[i];
79 auto recognized_parameter = true;
80
81 if (HasPrefix(param, "-tint_fuzzing_target=")) {
82 auto result = FuzzingTarget::kNone;
83
84 std::stringstream ss(param + sizeof("-tint_fuzzing_target=") - 1);
85 for (std::string value; std::getline(ss, value, ',');) {
86 auto tmp = FuzzingTarget::kNone;
87 if (!ParseFuzzingTarget(value.c_str(), &tmp)) {
88 InvalidParam(param);
89 }
90 result = result | tmp;
91 }
92
93 if (result == FuzzingTarget::kNone) {
94 InvalidParam(param);
95 }
96
97 cli_params.fuzzing_target = result;
98 } else if (!strcmp(param, "-tint_help")) {
99 help = true;
100 } else {
101 recognized_parameter = false;
102 }
103
104 if (recognized_parameter) {
105 // Remove the recognized parameter from the list of all parameters by
106 // swapping it with the last one. This will suppress warnings in the
107 // libFuzzer about unrecognized parameters. By default, libFuzzer thinks
108 // that all user-defined parameters start with two dashes. However, we are
109 // forced to use a single one to make the fuzzer compatible with the
110 // ClusterFuzz.
111 std::swap(argv[i], argv[*argc - 1]);
112 *argc -= 1;
113 }
114 }
115
116 if (help) {
117 std::cout << kHelpMessage << std::endl;
118 exit(0);
119 }
120
121 return cli_params;
122 }
123
124 } // namespace regex_fuzzer
125 } // namespace fuzzers
126 } // namespace tint
127