1/*
2 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17 */
18#include <xfs.h>
19
20static mutex_t	uuid_monitor;
21static int	uuid_table_size;
22static uuid_t	*uuid_table;
23
24/* IRIX interpretation of an uuid_t */
25typedef struct {
26	__be32	uu_timelow;
27	__be16	uu_timemid;
28	__be16	uu_timehi;
29	__be16	uu_clockseq;
30	__be16	uu_node[3];
31} xfs_uu_t;
32
33/*
34 * uuid_getnodeuniq - obtain the node unique fields of a UUID.
35 *
36 * This is not in any way a standard or condoned UUID function;
37 * it just something that's needed for user-level file handles.
38 */
39void
40uuid_getnodeuniq(uuid_t *uuid, int fsid [2])
41{
42	xfs_uu_t *uup = (xfs_uu_t *)uuid;
43
44	fsid[0] = (be16_to_cpu(uup->uu_clockseq) << 16) |
45		   be16_to_cpu(uup->uu_timemid);
46	fsid[1] = be32_to_cpu(uup->uu_timelow);
47}
48
49void
50uuid_create_nil(uuid_t *uuid)
51{
52	memset(uuid, 0, sizeof(*uuid));
53}
54
55int
56uuid_is_nil(uuid_t *uuid)
57{
58	int	i;
59	char	*cp = (char *)uuid;
60
61	if (uuid == NULL)
62		return 0;
63	/* implied check of version number here... */
64	for (i = 0; i < sizeof *uuid; i++)
65		if (*cp++) return 0;	/* not nil */
66	return 1;	/* is nil */
67}
68
69int
70uuid_equal(uuid_t *uuid1, uuid_t *uuid2)
71{
72	return memcmp(uuid1, uuid2, sizeof(uuid_t)) ? 0 : 1;
73}
74
75/*
76 * Given a 128-bit uuid, return a 64-bit value by adding the top and bottom
77 * 64-bit words.  NOTE: This function can not be changed EVER.  Although
78 * brain-dead, some applications depend on this 64-bit value remaining
79 * persistent.  Specifically, DMI vendors store the value as a persistent
80 * filehandle.
81 */
82__uint64_t
83uuid_hash64(uuid_t *uuid)
84{
85	__uint64_t	*sp = (__uint64_t *)uuid;
86
87	return sp[0] + sp[1];
88}
89
90int
91uuid_table_insert(uuid_t *uuid)
92{
93	int	i, hole;
94
95	mutex_lock(&uuid_monitor);
96	for (i = 0, hole = -1; i < uuid_table_size; i++) {
97		if (uuid_is_nil(&uuid_table[i])) {
98			hole = i;
99			continue;
100		}
101		if (uuid_equal(uuid, &uuid_table[i])) {
102			mutex_unlock(&uuid_monitor);
103			return 0;
104		}
105	}
106	if (hole < 0) {
107		uuid_table = kmem_realloc(uuid_table,
108			(uuid_table_size + 1) * sizeof(*uuid_table),
109			uuid_table_size  * sizeof(*uuid_table),
110			KM_SLEEP);
111		hole = uuid_table_size++;
112	}
113	uuid_table[hole] = *uuid;
114	mutex_unlock(&uuid_monitor);
115	return 1;
116}
117
118void
119uuid_table_remove(uuid_t *uuid)
120{
121	int	i;
122
123	mutex_lock(&uuid_monitor);
124	for (i = 0; i < uuid_table_size; i++) {
125		if (uuid_is_nil(&uuid_table[i]))
126			continue;
127		if (!uuid_equal(uuid, &uuid_table[i]))
128			continue;
129		uuid_create_nil(&uuid_table[i]);
130		break;
131	}
132	ASSERT(i < uuid_table_size);
133	mutex_unlock(&uuid_monitor);
134}
135
136void
137uuid_init(void)
138{
139	mutex_init(&uuid_monitor);
140}
141