xref: /freebsd/stand/libsa/uuid_from_string.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * Copyright (c) 2015 M. Warner Losh <imp@FreeBSD.org>
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  *
25  * $FreeBSD$
26  */
27 
28 /*
29  * Note: some comments taken from lib/libc/uuid/uuid_from_string.c
30  * Copyright (c) 2002 Marcel Moolenaar
31  * Copyright (c) 2002 Hiten Mahesh Pandya
32  */
33 
34 
35 #include <stand.h>
36 #include <uuid.h>
37 
38 static int
39 hex2int(int ch)
40 {
41 	if (ch >= '0' && ch <= '9')
42 		return ch - '0';
43 	if (ch >= 'a' && ch <= 'f')
44 		return 10 + ch - 'a';
45 	if (ch >= 'A' && ch <= 'F')
46 		return 10 + ch - 'A';
47 	return 16;
48 }
49 
50 static uint32_t
51 fromhex(const char *s, int len, int *ok)
52 {
53 	uint32_t v;
54 	int i, h;
55 
56 	if (!*ok)
57 		return 0;
58 	v = 0;
59 	for (i = 0; i < len; i++) {
60 		h = hex2int(s[i]);
61 		if (h == 16) {
62 			*ok = 0;
63 			return v;
64 		}
65 		v = (v << 4) | h;
66 	}
67 	return v;
68 }
69 
70 /*
71  * uuid_from_string() - convert a string representation of an UUID into
72  *			a binary representation.
73  * See also:
74  *	http://www.opengroup.org/onlinepubs/009629399/uuid_from_string.htm
75  *
76  * NOTE: The sequence field is in big-endian, while the time fields are in
77  *	 native byte order.
78  *
79  * 01234567-89ab-cdef-0123-456789abcdef
80  * 000000000011111111112222222222333333
81  * 012345678901234567890123456789012345
82  *         -    -    -    -
83  * hhhhhhhh-hhhh-hhhh-bbbb-bbbbbbbbbbbb
84  *
85  */
86 void
87 uuid_from_string(const char *s, uuid_t *u, uint32_t *status)
88 {
89 	int ok = 1;
90 	int n;
91 
92 	if (s == NULL || *s == '\0') {
93 		uuid_create_nil(u, status);
94 		return;
95 	}
96 
97 	if (status != NULL)
98 		*status = uuid_s_invalid_string_uuid;
99 	if (strlen(s) != 36)
100 		return;
101 	/* Only support new format, check for all the right dashes */
102 	if (s[8] != '-' || s[13] != '-' || s[18] != '-' || s[23] != '-')
103 		return;
104 	/* native byte order */
105 	u->time_low                  = fromhex(s     , 8, &ok);
106 	u->time_mid                  = fromhex(s +  9, 4, &ok);
107 	u->time_hi_and_version       = fromhex(s + 14, 4, &ok);
108 	/* Big endian, but presented as a whole number so decode as such */
109 	u->clock_seq_hi_and_reserved = fromhex(s + 19, 2, &ok);
110 	u->clock_seq_low             = fromhex(s + 21, 2, &ok);
111 	u->node[0]                   = fromhex(s + 24, 2, &ok);
112 	u->node[1]                   = fromhex(s + 26, 2, &ok);
113 	u->node[2]                   = fromhex(s + 28, 2, &ok);
114 	u->node[3]                   = fromhex(s + 30, 2, &ok);
115 	u->node[4]                   = fromhex(s + 32, 2, &ok);
116 	u->node[5]                   = fromhex(s + 34, 2, &ok);
117 	if (!ok)
118 		return;
119 
120 	/* We have a successful scan. Check semantics... */
121 	n = u->clock_seq_hi_and_reserved;
122 	if ((n & 0x80) != 0x00 &&			/* variant 0? */
123 	    (n & 0xc0) != 0x80 &&			/* variant 1? */
124 	    (n & 0xe0) != 0xc0) {			/* variant 2? */
125 		if (status != NULL)
126 			*status = uuid_s_bad_version;
127 	} else {
128 		if (status != NULL)
129 			*status = uuid_s_ok;
130 	}
131 }
132