1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
|
/*
fat.c (09.11.10)
File Allocation Table creation code.
Copyright (C) 2011-2013 Andrew Nayenko
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <unistd.h>
#include "fat.h"
#include "cbm.h"
#include "uct.h"
#include "rootdir.h"
static off64_t fat_alignment(void)
{
return (off64_t) 128 * get_sector_size();
}
static off64_t fat_size(void)
{
return get_volume_size() / get_cluster_size() * sizeof(cluster_t);
}
static cluster_t fat_write_entry(struct exfat_dev* dev, cluster_t cluster,
cluster_t value)
{
le32_t fat_entry = cpu_to_le32(value);
if (exfat_write(dev, &fat_entry, sizeof(fat_entry)) < 0)
{
exfat_error("failed to write FAT entry 0x%x", value);
return 0;
}
return cluster + 1;
}
static cluster_t fat_write_entries(struct exfat_dev* dev, cluster_t cluster,
uint64_t length)
{
cluster_t end = cluster + DIV_ROUND_UP(length, get_cluster_size());
while (cluster < end - 1)
{
cluster = fat_write_entry(dev, cluster, cluster + 1);
if (cluster == 0)
return 0;
}
return fat_write_entry(dev, cluster, EXFAT_CLUSTER_END);
}
static int fat_write(struct exfat_dev* dev)
{
cluster_t c = 0;
if (!(c = fat_write_entry(dev, c, 0xfffffff8))) /* media type */
return 1;
if (!(c = fat_write_entry(dev, c, 0xffffffff))) /* some weird constant */
return 1;
if (!(c = fat_write_entries(dev, c, cbm.get_size())))
return 1;
if (!(c = fat_write_entries(dev, c, uct.get_size())))
return 1;
if (!(c = fat_write_entries(dev, c, rootdir.get_size())))
return 1;
return 0;
}
const struct fs_object fat =
{
.get_alignment = fat_alignment,
.get_size = fat_size,
.write = fat_write,
};
|
