libfuzzer_emulator.cpp

#include <iostream>
#include <vector>
#include <cstdint>
#include <filesystem>
#include <fstream>

extern "C" size_t LLVMFuzzerMutate(uint8_t* data, size_t size, size_t maxSize) {
    (void)data;
    (void)maxSize;

    return size;
}

extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv);
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);

namespace fs = std::filesystem;

static void run(const fs::path& filePath) {
    std::ifstream file(filePath, std::ios::binary);
    if (!file) {
        std::cerr << "Error opening file: " << filePath << std::endl;
        return;
    }

    file.seekg(0, std::ios::end);
    std::streampos fileSize = file.tellg();
    file.seekg(0, std::ios::beg);

    std::vector<uint8_t> data(fileSize);
    if (!file.read(reinterpret_cast<char*>(data.data()), fileSize)) {
        std::cerr << "Error reading file: " << filePath << std::endl;
        return;
    }

    static size_t counter;
    std::cout << "Run " << ++counter << ": " << filePath << std::endl;
    LLVMFuzzerTestOneInput(data.data(), data.size());
}

static void readFilesInDirectory(const fs::path& directoryPath) {
    for (const auto& entry : fs::recursive_directory_iterator(directoryPath)) {
        if (fs::is_regular_file(entry)) {
            const auto& filePath = entry.path();
            run(filePath);
        }
    }
}

int main(int argc, char* argv[]) {
    LLVMFuzzerInitialize(&argc, &argv);

    for (int i = 1; i < argc; ++i) {
        const std::string argument = argv[i];
        if (argument[0] == '-') {
            continue;
        }

        const fs::path filePath = argument;

        if (fs::exists(filePath)) {
            if (fs::is_regular_file(filePath)) {
                run(filePath);
            } else if (fs::is_directory(filePath)) {
                readFilesInDirectory(filePath);
            } else {
                std::cerr << "Unknown file type: " << filePath << std::endl;
            }
        } else {
            std::cerr << "File not found: " << filePath << std::endl;
        }
    }

    return 0;
}