1# SPDX-License-Identifier:      GPL-2.0+
2#
3# Copyright (c) 2018, Linaro Limited
4# Author: Takahiro Akashi <takahiro.akashi@linaro.org>
5
6"""Helper functions for dealing with filesystems"""
7
8import re
9import os
10from subprocess import call, check_call, check_output, CalledProcessError
11
12def mk_fs(config, fs_type, size, prefix, size_gran = 0x100000):
13    """Create a file system volume
14
15    Args:
16        config (u_boot_config): U-Boot configuration
17        fs_type (str): File system type, e.g. 'ext4'
18        size (int): Size of file system in bytes
19        prefix (str): Prefix string of volume's file name
20        size_gran (int): Size granularity of file system image in bytes
21
22    Raises:
23        CalledProcessError: if any error occurs when creating the filesystem
24    """
25    fs_img = f'{prefix}.{fs_type}.img'
26    fs_img = os.path.join(config.persistent_data_dir, fs_img)
27
28    if fs_type == 'fat12':
29        mkfs_opt = '-F 12'
30    elif fs_type == 'fat16':
31        mkfs_opt = '-F 16'
32    elif fs_type == 'fat32':
33        mkfs_opt = '-F 32'
34    else:
35        mkfs_opt = ''
36
37    if re.match('fat', fs_type):
38        fs_lnxtype = 'vfat'
39    else:
40        fs_lnxtype = fs_type
41
42    count = (size + size_gran - 1) // size_gran
43
44    # Some distributions do not add /sbin to the default PATH, where mkfs lives
45    if '/sbin' not in os.environ["PATH"].split(os.pathsep):
46        os.environ["PATH"] += os.pathsep + '/sbin'
47
48    try:
49        check_call(f'rm -f {fs_img}', shell=True)
50        check_call(f'dd if=/dev/zero of={fs_img} bs={size_gran} count={count}',
51                   shell=True)
52        check_call(f'mkfs.{fs_lnxtype} {mkfs_opt} {fs_img}', shell=True)
53        if fs_type == 'ext4':
54            sb_content = check_output(f'tune2fs -l {fs_img}',
55                                      shell=True).decode()
56            if 'metadata_csum' in sb_content:
57                check_call(f'tune2fs -O ^metadata_csum {fs_img}', shell=True)
58        return fs_img
59    except CalledProcessError:
60        call(f'rm -f {fs_img}', shell=True)
61        raise
62
63# Just for trying out
64if __name__ == "__main__":
65    import collections
66
67    CNF= collections.namedtuple('config', 'persistent_data_dir')
68
69    mk_fs(CNF('.'), 'ext4', 0x1000000, 'pref')
70