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In some cases we would like to generate a GUID and export it. Though it would require either casting to internal kernel types or an intermediate buffer. Instead we may achieve this by supplying a pointer to raw buffer and make a complimentary API to existing one for UUIDs. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: David Sterba <dsterba@suse.com>
133 lines
2.9 KiB
C
133 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Unified UUID/GUID definition
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*
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* Copyright (C) 2009, 2016 Intel Corp.
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* Huang Ying <ying.huang@intel.com>
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*/
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#include <linux/kernel.h>
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#include <linux/ctype.h>
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#include <linux/errno.h>
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#include <linux/export.h>
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#include <linux/uuid.h>
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#include <linux/random.h>
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const guid_t guid_null;
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EXPORT_SYMBOL(guid_null);
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const uuid_t uuid_null;
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EXPORT_SYMBOL(uuid_null);
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const u8 guid_index[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
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const u8 uuid_index[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
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/**
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* generate_random_uuid - generate a random UUID
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* @uuid: where to put the generated UUID
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*
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* Random UUID interface
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*
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* Used to create a Boot ID or a filesystem UUID/GUID, but can be
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* useful for other kernel drivers.
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*/
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void generate_random_uuid(unsigned char uuid[16])
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{
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get_random_bytes(uuid, 16);
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/* Set UUID version to 4 --- truly random generation */
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uuid[6] = (uuid[6] & 0x0F) | 0x40;
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/* Set the UUID variant to DCE */
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uuid[8] = (uuid[8] & 0x3F) | 0x80;
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}
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EXPORT_SYMBOL(generate_random_uuid);
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void generate_random_guid(unsigned char guid[16])
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{
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get_random_bytes(guid, 16);
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/* Set GUID version to 4 --- truly random generation */
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guid[7] = (guid[7] & 0x0F) | 0x40;
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/* Set the GUID variant to DCE */
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guid[8] = (guid[8] & 0x3F) | 0x80;
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}
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EXPORT_SYMBOL(generate_random_guid);
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static void __uuid_gen_common(__u8 b[16])
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{
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prandom_bytes(b, 16);
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/* reversion 0b10 */
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b[8] = (b[8] & 0x3F) | 0x80;
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}
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void guid_gen(guid_t *lu)
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{
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__uuid_gen_common(lu->b);
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/* version 4 : random generation */
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lu->b[7] = (lu->b[7] & 0x0F) | 0x40;
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}
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EXPORT_SYMBOL_GPL(guid_gen);
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void uuid_gen(uuid_t *bu)
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{
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__uuid_gen_common(bu->b);
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/* version 4 : random generation */
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bu->b[6] = (bu->b[6] & 0x0F) | 0x40;
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}
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EXPORT_SYMBOL_GPL(uuid_gen);
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/**
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* uuid_is_valid - checks if a UUID string is valid
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* @uuid: UUID string to check
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*
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* Description:
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* It checks if the UUID string is following the format:
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* xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
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*
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* where x is a hex digit.
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*
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* Return: true if input is valid UUID string.
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*/
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bool uuid_is_valid(const char *uuid)
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{
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unsigned int i;
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for (i = 0; i < UUID_STRING_LEN; i++) {
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if (i == 8 || i == 13 || i == 18 || i == 23) {
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if (uuid[i] != '-')
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return false;
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} else if (!isxdigit(uuid[i])) {
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return false;
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}
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}
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return true;
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}
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EXPORT_SYMBOL(uuid_is_valid);
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static int __uuid_parse(const char *uuid, __u8 b[16], const u8 ei[16])
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{
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static const u8 si[16] = {0,2,4,6,9,11,14,16,19,21,24,26,28,30,32,34};
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unsigned int i;
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if (!uuid_is_valid(uuid))
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return -EINVAL;
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for (i = 0; i < 16; i++) {
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int hi = hex_to_bin(uuid[si[i] + 0]);
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int lo = hex_to_bin(uuid[si[i] + 1]);
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b[ei[i]] = (hi << 4) | lo;
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}
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return 0;
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}
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int guid_parse(const char *uuid, guid_t *u)
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{
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return __uuid_parse(uuid, u->b, guid_index);
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}
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EXPORT_SYMBOL(guid_parse);
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int uuid_parse(const char *uuid, uuid_t *u)
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{
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return __uuid_parse(uuid, u->b, uuid_index);
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}
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EXPORT_SYMBOL(uuid_parse);
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