// Copyright 2022 Google LLC

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//      http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

// Adapter utility from fuzzer input to a temporary file, for fuzzing APIs that

// require a file instead of an input buffer.

#ifndef FUZZER_TEMP_FILE_H_

#define FUZZER_TEMP_FILE_H_

#include <stdint.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

// Pure-C interface for creating and cleaning up temporary files.

static char* fuzzer_get_tmpfile(const uint8_t* data, size_t size) {

    char* filename_buffer = strdup("/tmp/generate_temporary_file.XXXXXX");

    if (!filename_buffer) {

        perror("Failed to allocate file name buffer.");

        abort();

    }

    const int file_descriptor = mkstemp(filename_buffer);

    if (file_descriptor < 0) {

        perror("Failed to make temporary file.");

        abort();

    }

    FILE* file = fdopen(file_descriptor, "wb");

    if (!file) {

        perror("Failed to open file descriptor.");

        close(file_descriptor);

        abort();

    }

    const size_t bytes_written = fwrite(data, sizeof(uint8_t), size, file);

    if (bytes_written < size) {

        close(file_descriptor);

        fprintf(stderr, "Failed to write all bytes to file (%zu out of %zu)",

                bytes_written, size);

        abort();

    }

    fclose(file);

    return filename_buffer;

}

static void fuzzer_release_tmpfile(char* filename) {

    if (unlink(filename) != 0) {

        perror("WARNING: Failed to delete temporary file.");

    }

    free(filename);

}

// C++ RAII object for creating temporary files.

#ifdef __cplusplus

class FuzzerTemporaryFile {

    public:

        FuzzerTemporaryFile(const uint8_t* data, size_t size)

            : filename_(fuzzer_get_tmpfile(data, size)) {}

        ~FuzzerTemporaryFile() { fuzzer_release_tmpfile(filename_); }

        const char* filename() const { return filename_; }

    private:

        char* filename_;

};

#endif

#endif  // FUZZER_TEMP_FILE_H_