lib/uuid.c

   1 /*
   2  * Copyright 2011 Calxeda, Inc.
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <common.h>
   8 #include <linux/ctype.h>
   9 #include <errno.h>
  10 #include <common.h>
  11 #include <asm/io.h>
  12 #include <part_efi.h>
  13 #include <malloc.h>
  14
  15 /*
  16  * UUID - Universally Unique IDentifier - 128 bits unique number.
  17  *        There are 5 versions and one variant of UUID defined by RFC4122
  18  *        specification. A UUID contains a set of fields. The set varies
  19  *        depending on the version of the UUID, as shown below:
  20  *        - time, MAC address(v1),
  21  *        - user ID(v2),
  22  *        - MD5 of name or URL(v3),
  23  *        - random data(v4),
  24  *        - SHA-1 of name or URL(v5),
  25  *
  26  * Layout of UUID:
  27  * timestamp - 60-bit: time_low, time_mid, time_hi_and_version
  28  * version   - 4 bit (bit 4 through 7 of the time_hi_and_version)
  29  * clock seq - 14 bit: clock_seq_hi_and_reserved, clock_seq_low
  30  * variant:  - bit 6 and 7 of clock_seq_hi_and_reserved
  31  * node      - 48 bit
  32  *
  33  * source: https://www.ietf.org/rfc/rfc4122.txt
  34  *
  35  * UUID binary format (16 bytes):
  36  *
  37  * 4B-2B-2B-2B-6B (big endian - network byte order)
  38  *
  39  * UUID string is 36 length of characters (36 bytes):
  40  *
  41  * 0        9    14   19   24
  42  * xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
  43  *    be     be   be   be       be
  44  *
  45  * where x is a hexadecimal character. Fields are separated by '-'s.
  46  * When converting to a binary UUID, le means the field should be converted
  47  * to little endian and be means it should be converted to big endian.
  48  *
  49  * UUID is also used as GUID (Globally Unique Identifier) with the same binary
  50  * format but it differs in string format like below.
  51  *
  52  * GUID:
  53  * 0        9    14   19   24
  54  * xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
  55  *    le     le   le   be       be
  56  *
  57  * GUID is used e.g. in GPT (GUID Partition Table) as a partiions unique id.
  58  */
  59 int uuid_str_valid(const char *uuid)
  60 {
  61         int i, valid;
  62
  63         if (uuid == NULL)
  64                 return 0;
  65
  66         for (i = 0, valid = 1; uuid[i] && valid; i++) {
  67                 switch (i) {
  68                 case 8: case 13: case 18: case 23:
  69                         valid = (uuid[i] == '-');
  70                         break;
  71                 default:
  72                         valid = isxdigit(uuid[i]);
  73                         break;
  74                 }
  75         }
  76
  77         if (i != UUID_STR_LEN || !valid)
  78                 return 0;
  79
  80         return 1;
  81 }
  82
  83 /*
  84  * uuid_str_to_bin() - convert string UUID or GUID to big endian binary data.
  85  *
  86  * @param uuid_str - pointer to UUID or GUID string [37B]
  87  * @param uuid_bin - pointer to allocated array for big endian output [16B]
  88  * @str_format     - UUID string format: 0 - UUID; 1 - GUID
  89  */
  90 int uuid_str_to_bin(char *uuid_str, unsigned char *uuid_bin, int str_format)
  91 {
  92         uint16_t tmp16;
  93         uint32_t tmp32;
  94         uint64_t tmp64;
  95
  96         if (!uuid_str_valid(uuid_str))
  97                 return -EINVAL;
  98
  99         if (str_format == UUID_STR_FORMAT_STD) {
 100                 tmp32 = cpu_to_be32(simple_strtoul(uuid_str, NULL, 16));
 101                 memcpy(uuid_bin, &tmp32, 4);
 102
 103                 tmp16 = cpu_to_be16(simple_strtoul(uuid_str + 9, NULL, 16));
 104                 memcpy(uuid_bin + 4, &tmp16, 2);
 105
 106                 tmp16 = cpu_to_be16(simple_strtoul(uuid_str + 14, NULL, 16));
 107                 memcpy(uuid_bin + 6, &tmp16, 2);
 108         } else {
 109                 tmp32 = cpu_to_le32(simple_strtoul(uuid_str, NULL, 16));
 110                 memcpy(uuid_bin, &tmp32, 4);
 111
 112                 tmp16 = cpu_to_le16(simple_strtoul(uuid_str + 9, NULL, 16));
 113                 memcpy(uuid_bin + 4, &tmp16, 2);
 114
 115                 tmp16 = cpu_to_le16(simple_strtoul(uuid_str + 14, NULL, 16));
 116                 memcpy(uuid_bin + 6, &tmp16, 2);
 117         }
 118
 119         tmp16 = cpu_to_be16(simple_strtoul(uuid_str + 19, NULL, 16));
 120         memcpy(uuid_bin + 8, &tmp16, 2);
 121
 122         tmp64 = cpu_to_be64(simple_strtoull(uuid_str + 24, NULL, 16));
 123         memcpy(uuid_bin + 10, (char *)&tmp64 + 2, 6);
 124
 125         return 0;
 126 }
 127
 128 /*
 129  * uuid_bin_to_str() - convert big endian binary data to string UUID or GUID.
 130  *
 131  * @param uuid_bin - pointer to binary data of UUID (big endian) [16B]
 132  * @param uuid_str - pointer to allocated array for output string [37B]
 133  * @str_format     - UUID string format: 0 - UUID; 1 - GUID
 134  */
 135 void uuid_bin_to_str(unsigned char *uuid_bin, char *uuid_str, int str_format)
 136 {
 137         const u8 uuid_char_order[UUID_BIN_LEN] = {0, 1, 2, 3, 4, 5, 6, 7, 8,
 138                                                   9, 10, 11, 12, 13, 14, 15};
 139         const u8 guid_char_order[UUID_BIN_LEN] = {3, 2, 1, 0, 5, 4, 7, 6, 8,
 140                                                   9, 10, 11, 12, 13, 14, 15};
 141         const u8 *char_order;
 142         int i;
 143
 144         /*
 145          * UUID and GUID bin data - always in big endian:
 146          * 4B-2B-2B-2B-6B
 147          * be be be be be
 148          */
 149         if (str_format == UUID_STR_FORMAT_STD)
 150                 char_order = uuid_char_order;
 151         else
 152                 char_order = guid_char_order;
 153
 154         for (i = 0; i < 16; i++) {
 155                 sprintf(uuid_str, "%02x", uuid_bin[char_order[i]]);
 156                 uuid_str += 2;
 157                 switch (i) {
 158                 case 3:
 159                 case 5:
 160                 case 7:
 161                 case 9:
 162                         *uuid_str++ = '-';
 163                         break;
 164                 }
 165         }
 166 }
 167
 168 /*
 169  * gen_rand_uuid() - this function generates a random binary UUID version 4.
 170  *                   In this version all fields beside 4 bits of version and
 171  *                   2 bits of variant are randomly generated.
 172  *
 173  * @param uuid_bin - pointer to allocated array [16B]. Output is in big endian.
 174 */
 175 #if defined(CONFIG_RANDOM_UUID) || defined(CONFIG_CMD_UUID)
 176 void gen_rand_uuid(unsigned char *uuid_bin)
 177 {
 178         struct uuid uuid;
 179         unsigned int *ptr = (unsigned int *)&uuid;
 180         int i;
 181
 182         /* Set all fields randomly */
 183         for (i = 0; i < sizeof(struct uuid) / sizeof(*ptr); i++)
 184                 *(ptr + i) = cpu_to_be32(rand());
 185
 186         clrsetbits_be16(&uuid.time_hi_and_version,
 187                         UUID_VERSION_MASK,
 188                         UUID_VERSION << UUID_VERSION_SHIFT);
 189
 190         clrsetbits_8(&uuid.clock_seq_hi_and_reserved,
 191                      UUID_VARIANT_MASK,
 192                      UUID_VARIANT << UUID_VARIANT_SHIFT);
 193
 194         memcpy(uuid_bin, &uuid, sizeof(struct uuid));
 195 }
 196
 197 /*
 198  * gen_rand_uuid_str() - this function generates UUID v4 (random) in two string
 199  *                       formats UUID or GUID.
 200  *
 201  * @param uuid_str - pointer to allocated array [37B].
 202  * @param          - uuid output type: UUID - 0, GUID - 1
 203  */
 204 void gen_rand_uuid_str(char *uuid_str, int str_format)
 205 {
 206         unsigned char uuid_bin[UUID_BIN_LEN];
 207
 208         /* Generate UUID (big endian) */
 209         gen_rand_uuid(uuid_bin);
 210
 211         /* Convert UUID bin to UUID or GUID formated STRING  */
 212         uuid_bin_to_str(uuid_bin, uuid_str, str_format);
 213 }
 214
 215 #ifdef CONFIG_CMD_UUID
 216 int do_uuid(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 217 {
 218         char uuid[UUID_STR_LEN + 1];
 219         int str_format;
 220
 221         if (!strcmp(argv[0], "uuid"))
 222                 str_format = UUID_STR_FORMAT_STD;
 223         else
 224                 str_format = UUID_STR_FORMAT_GUID;
 225
 226         if (argc > 2)
 227                 return CMD_RET_USAGE;
 228
 229         gen_rand_uuid_str(uuid, str_format);
 230
 231         if (argc == 1)
 232                 printf("%s\n", uuid);
 233         else
 234                 setenv(argv[1], uuid);
 235
 236         return CMD_RET_SUCCESS;
 237 }
 238
 239 U_BOOT_CMD(uuid, CONFIG_SYS_MAXARGS, 1, do_uuid,
 240            "UUID - generate random Universally Unique Identifier",
 241            "[<varname>]\n"
 242            "Argument:\n"
 243            "varname: for set result in a environment variable\n"
 244            "e.g. uuid uuid_env"
 245 );
 246
 247 U_BOOT_CMD(guid, CONFIG_SYS_MAXARGS, 1, do_uuid,
 248            "GUID - generate Globally Unique Identifier based on random UUID",
 249            "[<varname>]\n"
 250            "Argument:\n"
 251            "varname: for set result in a environment variable\n"
 252            "e.g. guid guid_env"
 253 );
 254 #endif /* CONFIG_CMD_UUID */
 255 #endif /* CONFIG_RANDOM_UUID || CONFIG_CMD_UUID */