fs_mgr/fs_mgr_format.cpp

/*
 * Copyright (C) 2015 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 <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <errno.h>
#include <cutils/partition_utils.h>
#include <sys/mount.h>

#include <ext4_utils/ext4.h>
#include <ext4_utils/ext4_utils.h>
#include <logwrap/logwrap.h>
#include <selinux/android.h>
#include <selinux/label.h>
#include <selinux/selinux.h>

#include "fs_mgr_priv.h"
#include "cryptfs.h"

static int format_ext4(char *fs_blkdev, char *fs_mnt_point, bool crypt_footer)
{
    uint64_t dev_sz;
    int fd, rc = 0;

    if ((fd = open(fs_blkdev, O_WRONLY)) < 0) {
        PERROR << "Cannot open block device";
        return -1;
    }

    if ((ioctl(fd, BLKGETSIZE64, &dev_sz)) == -1) {
        PERROR << "Cannot get block device size";
        close(fd);
        return -1;
    }

    close(fd);

    /* Format the partition using the calculated length */
    if (crypt_footer) {
        dev_sz -= CRYPT_FOOTER_OFFSET;
    }

    std::string size_str = std::to_string(dev_sz / 4096);
    const char* const mke2fs_args[] = {
        "/system/bin/mke2fs", "-t", "ext4", "-b", "4096", fs_blkdev, size_str.c_str(), nullptr};

    rc = android_fork_execvp_ext(arraysize(mke2fs_args), const_cast<char**>(mke2fs_args), NULL,
                                 true, LOG_KLOG, true, nullptr, nullptr, 0);
    if (rc) {
        LERROR << "mke2fs returned " << rc;
        return rc;
    }

    const char* const e2fsdroid_args[] = {
        "/system/bin/e2fsdroid",
        "-e",
        "-a",
        fs_mnt_point,
        fs_blkdev,
        nullptr};

    rc = android_fork_execvp_ext(arraysize(e2fsdroid_args), const_cast<char**>(e2fsdroid_args),
                                 NULL, true, LOG_KLOG, true, nullptr, nullptr, 0);
    if (rc) {
        LERROR << "e2fsdroid returned " << rc;
    }

    return rc;
}

static int format_f2fs(char *fs_blkdev)
{
    const char* const args[] = {"/system/bin/make_f2fs", "-f", "-O encrypt", fs_blkdev, nullptr};

    return android_fork_execvp_ext(arraysize(args), const_cast<char**>(args), NULL, true,
                                   LOG_KLOG, true, nullptr, nullptr, 0);
}

int fs_mgr_do_format(struct fstab_rec *fstab, bool crypt_footer)
{
    int rc = -EINVAL;

    LERROR << __FUNCTION__ << ": Format " << fstab->blk_device
           << " as '" << fstab->fs_type << "'";

    if (!strncmp(fstab->fs_type, "f2fs", 4)) {
        rc = format_f2fs(fstab->blk_device);
    } else if (!strncmp(fstab->fs_type, "ext4", 4)) {
        rc = format_ext4(fstab->blk_device, fstab->mount_point, crypt_footer);
    } else {
        LERROR << "File system type '" << fstab->fs_type << "' is not supported";
    }

    return rc;
}