summaryrefslogtreecommitdiff
path: root/util-linux/volume_id/get_devname.c
blob: ac69f78c451b5eb39965ef0ac447640dc71a1d92 (plain)
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
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
/* vi: set sw=4 ts=4: */
/*
 * Support functions for mounting devices by label/uuid
 *
 * Copyright (C) 2006 by Jason Schoon <floydpink@gmail.com>
 * Some portions cribbed from e2fsprogs, util-linux, dosfstools
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "volume_id_internal.h"

//#define BLKGETSIZE64 _IOR(0x12,114,size_t)

static struct uuidCache_s {
	struct uuidCache_s *next;
//	int major, minor;
	char *device;
	char *label;
	char *uc_uuid; /* prefix makes it easier to grep for */
} *uuidCache;

/* Returns !0 on error.
 * Otherwise, returns malloc'ed strings for label and uuid
 * (and they can't be NULL, although they can be "").
 * NB: closes fd. */
static int
get_label_uuid(int fd, char **label, char **uuid)
{
	int rv = 1;
	uint64_t size;
	struct volume_id *vid;

	/* fd is owned by vid now */
	vid = volume_id_open_node(fd);

	if (ioctl(/*vid->*/fd, BLKGETSIZE64, &size) != 0)
		size = 0;

	if (volume_id_probe_all(vid, /*0,*/ size) != 0)
		goto ret;

	if (vid->label[0] != '\0' || vid->uuid[0] != '\0') {
		*label = xstrndup(vid->label, sizeof(vid->label));
		*uuid  = xstrndup(vid->uuid, sizeof(vid->uuid));
		dbg("found label '%s', uuid '%s' on %s", *label, *uuid, device);
		rv = 0;
	}
 ret:
	free_volume_id(vid); /* also closes fd */
	return rv;
}

/* NB: we take ownership of (malloc'ed) label and uuid */
static void
uuidcache_addentry(char *device, /*int major, int minor,*/ char *label, char *uuid)
{
	struct uuidCache_s *last;

	if (!uuidCache) {
		last = uuidCache = xzalloc(sizeof(*uuidCache));
	} else {
		for (last = uuidCache; last->next; last = last->next)
			continue;
		last->next = xzalloc(sizeof(*uuidCache));
		last = last->next;
	}
	/*last->next = NULL; - xzalloc did it*/
//	last->major = major;
//	last->minor = minor;
	last->device = device;
	last->label = label;
	last->uc_uuid = uuid;
}

/* If get_label_uuid() on device_name returns success,
 * add a cache entry for this device.
 * If device node does not exist, it will be temporarily created. */
static int FAST_FUNC
uuidcache_check_device(const char *device,
		struct stat *statbuf,
		void *userData UNUSED_PARAM,
		int depth UNUSED_PARAM)
{
	char *uuid = uuid; /* for compiler */
	char *label = label;
	int fd;

	if (!S_ISBLK(statbuf->st_mode))
		return TRUE;

	fd = open(device, O_RDONLY);
	if (fd < 0)
		return TRUE;

	/* get_label_uuid() closes fd in all cases (success & failure) */
	if (get_label_uuid(fd, &label, &uuid) == 0) {
		/* uuidcache_addentry() takes ownership of all three params */
		uuidcache_addentry(xstrdup(device), /*ma, mi,*/ label, uuid);
	}
	return TRUE;
}

static void
uuidcache_init(void)
{
	if (uuidCache)
		return;

	/* We were scanning /proc/partitions
	 * and /proc/sys/dev/cdrom/info here.
	 * Missed volume managers. I see that "standard" blkid uses these:
	 * /dev/mapper/control
	 * /proc/devices
	 * /proc/evms/volumes
	 * /proc/lvm/VGs
	 * This is unacceptably complex. Let's just scan /dev.
	 * (Maybe add scanning of /sys/block/XXX/dev for devices
	 * somehow not having their /dev/XXX entries created?) */

	recursive_action("/dev", ACTION_RECURSE,
		uuidcache_check_device, /* file_action */
		NULL, /* dir_action */
		NULL, /* userData */
		0 /* depth */);
}

#define UUID   1
#define VOL    2

#ifdef UNUSED
static char *
get_spec_by_x(int n, const char *t, int *majorPtr, int *minorPtr)
{
	struct uuidCache_s *uc;

	uuidcache_init();
	uc = uuidCache;

	while (uc) {
		switch (n) {
		case UUID:
			if (strcmp(t, uc->uc_uuid) == 0) {
				*majorPtr = uc->major;
				*minorPtr = uc->minor;
				return uc->device;
			}
			break;
		case VOL:
			if (strcmp(t, uc->label) == 0) {
				*majorPtr = uc->major;
				*minorPtr = uc->minor;
				return uc->device;
			}
			break;
		}
		uc = uc->next;
	}
	return NULL;
}

static unsigned char
fromhex(char c)
{
	if (isdigit(c))
		return (c - '0');
	return ((c|0x20) - 'a' + 10);
}

static char *
get_spec_by_uuid(const char *s, int *major, int *minor)
{
	unsigned 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, (char *)uuid, major, minor);

 bad_uuid:
	fprintf(stderr, _("mount: bad UUID"));
	return 0;
}

static char *
get_spec_by_volume_label(const char *s, int *major, int *minor)
{
	return get_spec_by_x(VOL, s, major, minor);
}
#endif // UNUSED

/* Used by blkid */
void display_uuid_cache(void)
{
	struct uuidCache_s *u;

	uuidcache_init();
	u = uuidCache;
	while (u) {
		printf("%s:", u->device);
		if (u->label[0])
			printf(" LABEL=\"%s\"", u->label);
		if (u->uc_uuid[0])
			printf(" UUID=\"%s\"", u->uc_uuid);
		bb_putchar('\n');
		u = u->next;
	}
}

/* Used by mount and findfs */

char *get_devname_from_label(const char *spec)
{
	struct uuidCache_s *uc;

	uuidcache_init();
	uc = uuidCache;
	while (uc) {
		if (uc->label[0] && strcmp(spec, uc->label) == 0) {
			return xstrdup(uc->device);
		}
		uc = uc->next;
	}
	return NULL;
}

char *get_devname_from_uuid(const char *spec)
{
	struct uuidCache_s *uc;

	uuidcache_init();
	uc = uuidCache;
	while (uc) {
		/* case of hex numbers doesn't matter */
		if (strcasecmp(spec, uc->uc_uuid) == 0) {
			return xstrdup(uc->device);
		}
		uc = uc->next;
	}
	return NULL;
}