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
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
/*
* Copyright (C) 2010 Andrew Nayenko <resver@gmail.com>
*
* This file may be redistributed under the terms of the
* GNU Lesser General Public License.
*/
#include <stdio.h>
#include <string.h>
#include <math.h>
#include "blkidP.h"
#include "probe.h"
#define le32_to_cpu(x) blkid_le32(x)
typedef __u8 uint8_t;
typedef __u16 uint16_t;
typedef __u32 uint32_t;
typedef __uint64_t uint64_t;
typedef struct blkid_probe* blkid_probe;
struct exfat_super_block {
__u8 jump[3];
__u8 oem_name[8];
__u8 __unused1[53];
__u64 block_start;
__u64 block_count;
__u32 fat_block_start;
__u32 fat_block_count;
__u32 cluster_block_start;
__u32 cluster_count;
__u32 rootdir_cluster;
__u8 volume_serial[4];
struct {
__u8 minor;
__u8 major;
} version;
__u16 volume_state;
__u8 block_bits;
__u8 bpc_bits;
__u8 fat_count;
__u8 drive_no;
__u8 allocated_percent;
} __attribute__((__packed__));
struct exfat_entry_label {
__u8 type;
__u8 length;
__u8 name[30];
} __attribute__((__packed__));
#define BLOCK_SIZE(sb) (1 << (sb)->block_bits)
#define CLUSTER_SIZE(sb) (BLOCK_SIZE(sb) << (sb)->bpc_bits)
#define EXFAT_FIRST_DATA_CLUSTER 2
#define EXFAT_LAST_DATA_CLUSTER 0xffffff6
#define EXFAT_ENTRY_SIZE 32
#define EXFAT_ENTRY_EOD 0x00
#define EXFAT_ENTRY_LABEL 0x83
static blkid_loff_t block_to_offset(const struct exfat_super_block *sb,
blkid_loff_t block)
{
return (blkid_loff_t) block << sb->block_bits;
}
static blkid_loff_t cluster_to_block(const struct exfat_super_block *sb,
uint32_t cluster)
{
return le32_to_cpu(sb->cluster_block_start) +
((blkid_loff_t) (cluster - EXFAT_FIRST_DATA_CLUSTER)
<< sb->bpc_bits);
}
static blkid_loff_t cluster_to_offset(const struct exfat_super_block *sb,
uint32_t cluster)
{
return block_to_offset(sb, cluster_to_block(sb, cluster));
}
extern unsigned char *blkid_probe_get_buffer(struct blkid_probe *pr,
blkid_loff_t off, size_t len);
static uint32_t next_cluster(blkid_probe pr,
const struct exfat_super_block *sb, uint32_t cluster)
{
uint32_t *next;
blkid_loff_t fat_offset;
fat_offset = block_to_offset(sb, le32_to_cpu(sb->fat_block_start))
+ (blkid_loff_t) cluster * sizeof(cluster);
next = (uint32_t *) blkid_probe_get_buffer(pr, fat_offset,
sizeof(uint32_t));
if (!next)
return 0;
return le32_to_cpu(*next);
}
static struct exfat_entry_label *find_label(blkid_probe pr,
const struct exfat_super_block *sb)
{
uint32_t cluster = le32_to_cpu(sb->rootdir_cluster);
blkid_loff_t offset = cluster_to_offset(sb, cluster);
uint8_t *entry;
for (;;) {
entry = (uint8_t *) blkid_probe_get_buffer(pr, offset,
EXFAT_ENTRY_SIZE);
if (!entry)
return NULL;
if (entry[0] == EXFAT_ENTRY_EOD)
return NULL;
if (entry[0] == EXFAT_ENTRY_LABEL)
return (struct exfat_entry_label *) entry;
offset += EXFAT_ENTRY_SIZE;
if (offset % CLUSTER_SIZE(sb) == 0) {
cluster = next_cluster(pr, sb, cluster);
if (cluster < EXFAT_FIRST_DATA_CLUSTER)
return NULL;
if (cluster > EXFAT_LAST_DATA_CLUSTER)
return NULL;
offset = cluster_to_offset(sb, cluster);
}
}
}
static void unicode_16le_to_utf8(unsigned char *str, int out_len,
const unsigned char *buf, int in_len)
{
int i, j;
unsigned int c;
for (i = j = 0; i + 2 <= in_len; i += 2) {
c = (buf[i+1] << 8) | buf[i];
if (c == 0) {
str[j] = '\0';
break;
} else if (c < 0x80) {
if (j+1 >= out_len)
break;
str[j++] = (unsigned char) c;
} else if (c < 0x800) {
if (j+2 >= out_len)
break;
str[j++] = (unsigned char) (0xc0 | (c >> 6));
str[j++] = (unsigned char) (0x80 | (c & 0x3f));
} else {
if (j+3 >= out_len)
break;
str[j++] = (unsigned char) (0xe0 | (c >> 12));
str[j++] = (unsigned char) (0x80 | ((c >> 6) & 0x3f));
str[j++] = (unsigned char) (0x80 | (c & 0x3f));
}
}
str[j] = '\0';
}
int probe_exfat(struct blkid_probe *probe,
struct blkid_magic *id __BLKID_ATTR((unused)),
unsigned char *buf)
{
struct exfat_super_block *sb;
struct exfat_entry_label *label;
char serno[10];
sb = (struct exfat_super_block *) buf;
sprintf(serno, "%02X%02X-%02X%02X",
sb->volume_serial[3], sb->volume_serial[2],
sb->volume_serial[1], sb->volume_serial[0]);
blkid_set_tag(probe->dev, "UUID", serno, sizeof(serno)-1);
label = find_label(probe, sb);
if (label) {
char utf8_label[128];
unicode_16le_to_utf8(utf8_label, sizeof(utf8_label), label->name, label->length * 2);
blkid_set_tag(probe->dev, "LABEL", utf8_label, 0);
}
return 0;
}
|
