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
|
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <unistd.h>
#include "sundries.h" /* for xstrdup */
#include "linux_fs.h"
#include "mount_by_label.h"
#define PROC_PARTITIONS "/proc/partitions"
#define DEVLABELDIR "/dev"
static FILE *procpt;
static void
procptclose(void) {
if (procpt)
fclose (procpt);
procpt = 0;
}
static int
procptopen(void) {
return ((procpt = fopen(PROC_PARTITIONS, "r")) != NULL);
}
static char *
procptnext(void) {
char line[100];
char *s;
int ma, mi, sz;
static char ptname[100];
while (fgets(line, sizeof(line), procpt)) {
if (sscanf (line, " %d %d %d %[^\n]\n", &ma, &mi, &sz, ptname) != 4)
continue;
/* skip extended partitions (heuristic: size 1) */
if (sz == 1)
continue;
/* skip entire disk (minor 0, 64, ... on ide; 0, 16, ... on sd) */
/* heuristic: partition name ends in a digit */
for(s = ptname; *s; s++);
if (isdigit(s[-1]))
return ptname;
}
return 0;
}
#define UUID 1
#define VOL 2
/* for now, only ext2 is supported */
static int
has_right_label(const char *device, int n, const char *label) {
/* start with a test for ext2, taken from mount_guess_fstype */
/* should merge these later */
int fd;
char *s;
struct ext2_super_block e2sb;
fd = open(device, O_RDONLY);
if (fd < 0)
return 0;
if (lseek(fd, 1024, SEEK_SET) != 1024
|| read(fd, (char *) &e2sb, sizeof(e2sb)) != sizeof(e2sb)
|| (ext2magic(e2sb) != EXT2_SUPER_MAGIC)) {
close(fd);
return 0;
}
close(fd);
/* superblock is ext2 - now what is its label? */
s = ((n == UUID) ? e2sb.s_uuid : e2sb.s_volume_name);
return (strncmp(s, label, 16) == 0);
}
static char *
get_spec_by_x(int n, const char *t) {
char *pt;
char device[110];
if(!procptopen())
return NULL;
while((pt = procptnext()) != NULL) {
/* Note: this is a heuristic only - there is no reason
why these devices should live in /dev.
Perhaps this directory should be specifiable by option.
One might for example have /devlabel with links to /dev
for the devices that may be accessed in this way.
(This is useful, if the cdrom on /dev/hdc must not
be accessed.)
*/
sprintf(device, "%s/%s", DEVLABELDIR, pt);
if (has_right_label(device, n, t)) {
procptclose();
return xstrdup(device);
}
}
procptclose();
return NULL;
}
static u_char
fromhex(char c) {
if (isdigit(c))
return (c - '0');
else if (islower(c))
return (c - 'a' + 10);
else
return (c - 'A' + 10);
}
char *
get_spec_by_uuid(const char *s) {
u_char uuid[16];
int i;
if (strlen(s) != 36 ||
s[8] != '-' || s[13] != '-' || s[18] != '-' || s[23] != '-')
goto bad_uuid;
for (i=0; i<16; i++) {
if (*s == '-') s++;
if (!isxdigit(s[0]) || !isxdigit(s[1]))
goto bad_uuid;
uuid[i] = ((fromhex(s[0])<<4) | fromhex(s[1]));
s += 2;
}
return get_spec_by_x(UUID, uuid);
bad_uuid:
die(EX_USAGE, "mount: bad UUID");
}
char *
get_spec_by_volume_label(const char *s) {
return get_spec_by_x(VOL, s);
}
|
