Function LLVMFuzzerTestOneInput

fuzz/cli11_app_fuzz.cpp:13–61

#include <string>

extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
    if(Size == 0) {
        return 0;
    }
    std::string parseString(reinterpret_cast<const char *>(Data), Size);

    CLI::FuzzApp fuzzdata;

    auto app = fuzzdata.generateApp();
    std::size_t pstring_start{0};
    try {
        pstring_start = fuzzdata.add_custom_options(app.get(), parseString);
    } catch(const CLI::ConstructionError &e) {
        return 0;  // Non-zero return values are reserved for future use.
    }

    try {
        if(pstring_start > 0) {
            app->parse(parseString.substr(pstring_start));
            // test to make sure no seg fault or other errors occur
            std::ignore = app->help("", CLI::AppFormatMode::All);
        } else {
            app->parse(parseString);
        }
    } catch(const CLI::HorribleError &he) {
        throw;
    } catch(const CLI::ParseError &e) {
        //(app)->exit(e);
        // this just indicates we caught an error known by CLI
        return 0;  // Non-zero return values are reserved for future use.
    }
    if(fuzzdata.supports_config_file()) {
        CLI::FuzzApp fuzzdata2;
        auto app2 = fuzzdata2.generateApp();
        // should be able to write the config to a file and read from it again
        std::string configOut = app->config_to_str();
        std::stringstream out(configOut);
        if(pstring_start > 0) {
            fuzzdata2.add_custom_options(app2.get(), parseString);
        }
        app2->parse_from_stream(out);
        auto result = fuzzdata2.compare(fuzzdata);
        if(!result) {
            throw CLI::ValidationError("fuzzer", "file input results don't match parse results");
        }
    }

    return 0;
}