1 /*
2 * Copyright (c) 2021-2023, Arm Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include <assert.h>
8 #include <errno.h>
9 #include <string.h>
10
11 #include <common/debug.h>
12 #include <common/uuid.h>
13
14 /* Return the hex nibble value of a char */
hex_val(char hex)15 static int8_t hex_val(char hex)
16 {
17 int8_t val = 0;
18
19 if ((hex >= '0') && (hex <= '9')) {
20 val = (int8_t)(hex - '0');
21 } else if ((hex >= 'a') && (hex <= 'f')) {
22 val = (int8_t)(hex - 'a' + 0xa);
23 } else if ((hex >= 'A') && (hex <= 'F')) {
24 val = (int8_t)(hex - 'A' + 0xa);
25 } else {
26 val = -1;
27 }
28
29 return val;
30 }
31
32 /*
33 * Read hex_src_len hex characters from hex_src, convert to bytes and
34 * store in buffer pointed to by dest
35 */
read_hex(uint8_t * dest,char * hex_src,unsigned int hex_src_len)36 static int read_hex(uint8_t *dest, char *hex_src, unsigned int hex_src_len)
37 {
38 int8_t nibble;
39 uint8_t byte;
40
41 /*
42 * The string length must be a multiple of 2 to represent an
43 * exact number of bytes.
44 */
45 assert((hex_src_len % 2U) == 0U);
46
47 for (unsigned int i = 0U; i < (hex_src_len / 2U); i++) {
48 nibble = 0;
49 byte = 0U;
50
51 nibble = hex_val(hex_src[2U * i]);
52 if (nibble < 0) {
53 return -1;
54 }
55 byte = (uint8_t)nibble;
56 byte <<= 4U;
57
58 nibble = hex_val(hex_src[(2U * i) + 1U]);
59 if (nibble < 0) {
60 return -1;
61 }
62 byte |= (uint8_t)nibble;
63
64 *dest = byte;
65 dest++;
66 }
67
68 return 0;
69 }
70
71 /* Parse UUIDs of the form aabbccdd-eeff-4099-8877-665544332211 */
read_uuid(uint8_t * dest,char * uuid)72 int read_uuid(uint8_t *dest, char *uuid)
73 {
74 int err;
75 uint8_t *dest_start = dest;
76
77 /* Check that we have enough characters */
78 if (strnlen(uuid, UUID_STRING_LENGTH) != UUID_STRING_LENGTH) {
79 WARN("UUID string is too short\n");
80 return -EINVAL;
81 }
82
83 /* aabbccdd */
84 err = read_hex(dest, uuid, 8);
85 uuid += 8;
86 dest += 4;
87
88 /* Check for '-' */
89 err |= ((*uuid == '-') ? 0 : -1);
90 uuid++;
91
92 /* eeff */
93 err |= read_hex(dest, uuid, 4);
94 uuid += 4;
95 dest += 2;
96
97 /* Check for '-' */
98 err |= ((*uuid == '-') ? 0 : -1);
99 uuid++;
100
101 /* 4099 */
102 err |= read_hex(dest, uuid, 4);
103 uuid += 4;
104 dest += 2;
105
106 /* Check for '-' */
107 err |= ((*uuid == '-') ? 0 : -1);
108 uuid++;
109
110 /* 8877 */
111 err |= read_hex(dest, uuid, 4);
112 uuid += 4;
113 dest += 2;
114
115 /* Check for '-' */
116 err |= ((*uuid == '-') ? 0 : -1);
117 uuid++;
118
119 /* 665544332211 */
120 err |= read_hex(dest, uuid, 12);
121 uuid += 12;
122 dest += 6;
123
124 if (err < 0) {
125 WARN("Error parsing UUID\n");
126 /* Clear the buffer on error */
127 memset((void *)dest_start, '\0', UUID_BYTES_LENGTH * sizeof(uint8_t));
128 return -EINVAL;
129 }
130
131 return 0;
132 }
133
134 /*
135 * Helper function to check if 2 UUIDs match.
136 */
uuid_match(uint32_t * uuid1,uint32_t * uuid2)137 bool uuid_match(uint32_t *uuid1, uint32_t *uuid2)
138 {
139 return !memcmp(uuid1, uuid2, sizeof(uint32_t) * 4);
140 }
141
142 /*
143 * Helper function to copy from one UUID struct to another.
144 */
copy_uuid(uint32_t * to_uuid,uint32_t * from_uuid)145 void copy_uuid(uint32_t *to_uuid, uint32_t *from_uuid)
146 {
147 to_uuid[0] = from_uuid[0];
148 to_uuid[1] = from_uuid[1];
149 to_uuid[2] = from_uuid[2];
150 to_uuid[3] = from_uuid[3];
151 }
152
is_null_uuid(uint32_t * uuid)153 bool is_null_uuid(uint32_t *uuid)
154 {
155 return (uuid[0] == 0 && uuid[1] == 0 &&
156 uuid[2] == 0 && uuid[3] == 0);
157 }
158
