fs_mgr/libdm/test_util.cpp

/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * 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.
 */

#include <fcntl.h>
#include <linux/memfd.h>
#include <stdio.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>

#include "test_util.h"

namespace android {
namespace dm {

using unique_fd = android::base::unique_fd;

// Create a temporary in-memory file. If size is non-zero, the file will be
// created with a fixed size.
unique_fd CreateTempFile(const std::string& name, size_t size) {
    unique_fd fd(syscall(__NR_memfd_create, name.c_str(), MFD_ALLOW_SEALING));
    if (fd < 0) {
        return {};
    }
    if (size) {
        if (ftruncate(fd, size) < 0) {
            perror("ftruncate");
            return {};
        }
        if (fcntl(fd, F_ADD_SEALS, F_SEAL_GROW | F_SEAL_SHRINK) < 0) {
            perror("fcntl");
            return {};
        }
    }
    return fd;
}

}  // namespace dm
}  // namespace android