1 /* 2 * Unified UUID/GUID definition 3 * 4 * Copyright (C) 2009, 2016 Intel Corp. 5 * Huang Ying <ying.huang@intel.com> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License version 9 * 2 as published by the Free Software Foundation; 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/ctype.h> 19 #include <linux/errno.h> 20 #include <linux/export.h> 21 #include <linux/uuid.h> 22 #include <linux/random.h> 23 24 const guid_t guid_null; 25 EXPORT_SYMBOL(guid_null); 26 const uuid_t uuid_null; 27 EXPORT_SYMBOL(uuid_null); 28 29 const u8 guid_index[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15}; 30 const u8 uuid_index[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}; 31 32 /** 33 * generate_random_uuid - generate a random UUID 34 * @uuid: where to put the generated UUID 35 * 36 * Random UUID interface 37 * 38 * Used to create a Boot ID or a filesystem UUID/GUID, but can be 39 * useful for other kernel drivers. 40 */ 41 void generate_random_uuid(unsigned char uuid[16]) 42 { 43 get_random_bytes(uuid, 16); 44 /* Set UUID version to 4 --- truly random generation */ 45 uuid[6] = (uuid[6] & 0x0F) | 0x40; 46 /* Set the UUID variant to DCE */ 47 uuid[8] = (uuid[8] & 0x3F) | 0x80; 48 } 49 EXPORT_SYMBOL(generate_random_uuid); 50 51 static void __uuid_gen_common(__u8 b[16]) 52 { 53 prandom_bytes(b, 16); 54 /* reversion 0b10 */ 55 b[8] = (b[8] & 0x3F) | 0x80; 56 } 57 58 void guid_gen(guid_t *lu) 59 { 60 __uuid_gen_common(lu->b); 61 /* version 4 : random generation */ 62 lu->b[7] = (lu->b[7] & 0x0F) | 0x40; 63 } 64 EXPORT_SYMBOL_GPL(guid_gen); 65 66 void uuid_gen(uuid_t *bu) 67 { 68 __uuid_gen_common(bu->b); 69 /* version 4 : random generation */ 70 bu->b[6] = (bu->b[6] & 0x0F) | 0x40; 71 } 72 EXPORT_SYMBOL_GPL(uuid_gen); 73 74 /** 75 * uuid_is_valid - checks if a UUID string is valid 76 * @uuid: UUID string to check 77 * 78 * Description: 79 * It checks if the UUID string is following the format: 80 * xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx 81 * 82 * where x is a hex digit. 83 * 84 * Return: true if input is valid UUID string. 85 */ 86 bool uuid_is_valid(const char *uuid) 87 { 88 unsigned int i; 89 90 for (i = 0; i < UUID_STRING_LEN; i++) { 91 if (i == 8 || i == 13 || i == 18 || i == 23) { 92 if (uuid[i] != '-') 93 return false; 94 } else if (!isxdigit(uuid[i])) { 95 return false; 96 } 97 } 98 99 return true; 100 } 101 EXPORT_SYMBOL(uuid_is_valid); 102 103 static int __uuid_parse(const char *uuid, __u8 b[16], const u8 ei[16]) 104 { 105 static const u8 si[16] = {0,2,4,6,9,11,14,16,19,21,24,26,28,30,32,34}; 106 unsigned int i; 107 108 if (!uuid_is_valid(uuid)) 109 return -EINVAL; 110 111 for (i = 0; i < 16; i++) { 112 int hi = hex_to_bin(uuid[si[i] + 0]); 113 int lo = hex_to_bin(uuid[si[i] + 1]); 114 115 b[ei[i]] = (hi << 4) | lo; 116 } 117 118 return 0; 119 } 120 121 int guid_parse(const char *uuid, guid_t *u) 122 { 123 return __uuid_parse(uuid, u->b, guid_index); 124 } 125 EXPORT_SYMBOL(guid_parse); 126 127 int uuid_parse(const char *uuid, uuid_t *u) 128 { 129 return __uuid_parse(uuid, u->b, uuid_index); 130 } 131 EXPORT_SYMBOL(uuid_parse); 132