uuid.c 1.8 KB

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  1. /*
  2. * Unified UUID/GUID definition
  3. *
  4. * Copyright (C) 2009, 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. * You should have received a copy of the GNU General Public License
  17. * along with this program; if not, write to the Free Software
  18. * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19. */
  20. #include <linux/kernel.h>
  21. #include <linux/export.h>
  22. #include <linux/uuid.h>
  23. #include <linux/random.h>
  24. /***************************************************************
  25. * Random UUID interface
  26. *
  27. * Used here for a Boot ID, but can be useful for other kernel
  28. * drivers.
  29. ***************************************************************/
  30. /*
  31. * Generate random UUID
  32. */
  33. void generate_random_uuid(unsigned char uuid[16])
  34. {
  35. get_random_bytes(uuid, 16);
  36. /* Set UUID version to 4 --- truly random generation */
  37. uuid[6] = (uuid[6] & 0x0F) | 0x40;
  38. /* Set the UUID variant to DCE */
  39. uuid[8] = (uuid[8] & 0x3F) | 0x80;
  40. }
  41. EXPORT_SYMBOL(generate_random_uuid);
  42. static void __uuid_gen_common(__u8 b[16])
  43. {
  44. prandom_bytes(b, 16);
  45. /* reversion 0b10 */
  46. b[8] = (b[8] & 0x3F) | 0x80;
  47. }
  48. void uuid_le_gen(uuid_le *lu)
  49. {
  50. __uuid_gen_common(lu->b);
  51. /* version 4 : random generation */
  52. lu->b[7] = (lu->b[7] & 0x0F) | 0x40;
  53. }
  54. EXPORT_SYMBOL_GPL(uuid_le_gen);
  55. void uuid_be_gen(uuid_be *bu)
  56. {
  57. __uuid_gen_common(bu->b);
  58. /* version 4 : random generation */
  59. bu->b[6] = (bu->b[6] & 0x0F) | 0x40;
  60. }
  61. EXPORT_SYMBOL_GPL(uuid_be_gen);