aboutsummaryrefslogtreecommitdiffstats
path: root/fs/xfs/support/uuid.c
blob: 5830c040ea7ebba66274eeebbdab553c206ab981 (plain) (blame)
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
/*
 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * 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.
 *
 * This program is distributed in the hope that it would 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, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include <xfs.h>

static DEFINE_MUTEX(uuid_monitor);
static int	uuid_table_size;
static uuid_t	*uuid_table;

/* IRIX interpretation of an uuid_t */
typedef struct {
	__be32	uu_timelow;
	__be16	uu_timemid;
	__be16	uu_timehi;
	__be16	uu_clockseq;
	__be16	uu_node[3];
} xfs_uu_t;

/*
 * uuid_getnodeuniq - obtain the node unique fields of a UUID.
 *
 * This is not in any way a standard or condoned UUID function;
 * it just something that's needed for user-level file handles.
 */
void
uuid_getnodeuniq(uuid_t *uuid, int fsid [2])
{
	xfs_uu_t *uup = (xfs_uu_t *)uuid;

	fsid[0] = (be16_to_cpu(uup->uu_clockseq) << 16) |
		   be16_to_cpu(uup->uu_timemid);
	fsid[1] = be32_to_cpu(uup->uu_timelow);
}

void
uuid_create_nil(uuid_t *uuid)
{
	memset(uuid, 0, sizeof(*uuid));
}

int
uuid_is_nil(uuid_t *uuid)
{
	int	i;
	char	*cp = (char *)uuid;

	if (uuid == NULL)
		return 0;
	/* implied check of version number here... */
	for (i = 0; i < sizeof *uuid; i++)
		if (*cp++) return 0;	/* not nil */
	return 1;	/* is nil */
}

int
uuid_equal(uuid_t *uuid1, uuid_t *uuid2)
{
	return memcmp(uuid1, uuid2, sizeof(uuid_t)) ? 0 : 1;
}

/*
 * Given a 128-bit uuid, return a 64-bit value by adding the top and bottom
 * 64-bit words.  NOTE: This function can not be changed EVER.  Although
 * brain-dead, some applications depend on this 64-bit value remaining
 * persistent.  Specifically, DMI vendors store the value as a persistent
 * filehandle.
 */
__uint64_t
uuid_hash64(uuid_t *uuid)
{
	__uint64_t	*sp = (__uint64_t *)uuid;

	return sp[0] + sp[1];
}

int
uuid_table_insert(uuid_t *uuid)
{
	int	i, hole;

	mutex_lock(&uuid_monitor);
	for (i = 0, hole = -1; i < uuid_table_size; i++) {
		if (uuid_is_nil(&uuid_table[i])) {
			hole = i;
			continue;
		}
		if (uuid_equal(uuid, &uuid_table[i])) {
			mutex_unlock(&uuid_monitor);
			return 0;
		}
	}
	if (hole < 0) {
		uuid_table = kmem_realloc(uuid_table,
			(uuid_table_size + 1) * sizeof(*uuid_table),
			uuid_table_size  * sizeof(*uuid_table),
			KM_SLEEP);
		hole = uuid_table_size++;
	}
	uuid_table[hole] = *uuid;
	mutex_unlock(&uuid_monitor);
	return 1;
}

void
uuid_table_remove(uuid_t *uuid)
{
	int	i;

	mutex_lock(&uuid_monitor);
	for (i = 0; i < uuid_table_size; i++) {
		if (uuid_is_nil(&uuid_table[i]))
			continue;
		if (!uuid_equal(uuid, &uuid_table[i]))
			continue;
		uuid_create_nil(&uuid_table[i]);
		break;
	}
	ASSERT(i < uuid_table_size);
	mutex_unlock(&uuid_monitor);
}