/src/matio/ossfuzz/fuzzer_temp_file.h

Source
// Copyright 2019 Google Inc.
//
// 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_

Coverage Report

Created: 2026-10-28 18:12