xref: /openbmc/qemu/util/uuid.c (revision 9c5ce8db2e5c2769ed2fd3d91928dd1853b5ce7c)
1 /*
2  *  QEMU UUID functions
3  *
4  *  Copyright 2016 Red Hat, Inc.
5  *
6  *  Authors:
7  *   Fam Zheng <famz@redhat.com>
8  *
9  * This program is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU General Public License as published by the Free
11  * Software Foundation; either version 2 of the License, or (at your option)
12  * any later version.
13  *
14  */
15 
16 #include "qemu/osdep.h"
17 #include "qemu-common.h"
18 #include "qemu/uuid.h"
19 #include "qemu/bswap.h"
20 
21 void qemu_uuid_generate(QemuUUID *uuid)
22 {
23     int i;
24     uint32_t tmp[4];
25 
26     QEMU_BUILD_BUG_ON(sizeof(QemuUUID) != 16);
27 
28     for (i = 0; i < 4; ++i) {
29         tmp[i] = g_random_int();
30     }
31     memcpy(uuid, tmp, sizeof(tmp));
32     /* Set the two most significant bits (bits 6 and 7) of the
33       clock_seq_hi_and_reserved to zero and one, respectively. */
34     uuid->data[8] = (uuid->data[8] & 0x3f) | 0x80;
35     /* Set the four most significant bits (bits 12 through 15) of the
36       time_hi_and_version field to the 4-bit version number.
37       */
38     uuid->data[6] = (uuid->data[6] & 0xf) | 0x40;
39 }
40 
41 int qemu_uuid_is_null(const QemuUUID *uu)
42 {
43     static QemuUUID null_uuid;
44     return memcmp(uu, &null_uuid, sizeof(QemuUUID)) == 0;
45 }
46 
47 void qemu_uuid_unparse(const QemuUUID *uuid, char *out)
48 {
49     const unsigned char *uu = &uuid->data[0];
50     snprintf(out, UUID_FMT_LEN + 1, UUID_FMT,
51              uu[0], uu[1], uu[2], uu[3], uu[4], uu[5], uu[6], uu[7],
52              uu[8], uu[9], uu[10], uu[11], uu[12], uu[13], uu[14], uu[15]);
53 }
54 
55 char *qemu_uuid_unparse_strdup(const QemuUUID *uuid)
56 {
57     const unsigned char *uu = &uuid->data[0];
58     return g_strdup_printf(UUID_FMT,
59                            uu[0], uu[1], uu[2], uu[3], uu[4], uu[5], uu[6],
60                            uu[7], uu[8], uu[9], uu[10], uu[11], uu[12],
61                            uu[13], uu[14], uu[15]);
62 }
63 
64 int qemu_uuid_parse(const char *str, QemuUUID *uuid)
65 {
66     unsigned char *uu = &uuid->data[0];
67     int ret;
68 
69     if (strlen(str) != 36) {
70         return -1;
71     }
72 
73     ret = sscanf(str, UUID_FMT, &uu[0], &uu[1], &uu[2], &uu[3],
74                  &uu[4], &uu[5], &uu[6], &uu[7], &uu[8], &uu[9],
75                  &uu[10], &uu[11], &uu[12], &uu[13], &uu[14],
76                  &uu[15]);
77 
78     if (ret != 16) {
79         return -1;
80     }
81     return 0;
82 }
83 
84 /* Swap from UUID format endian (BE) to the opposite or vice versa.
85  */
86 void qemu_uuid_bswap(QemuUUID *uuid)
87 {
88     assert(QEMU_PTR_IS_ALIGNED(uuid, sizeof(uint32_t)));
89     bswap32s(&uuid->fields.time_low);
90     bswap16s(&uuid->fields.time_mid);
91     bswap16s(&uuid->fields.time_high_and_version);
92 }
93