GenUUID/vtoy_gen_uuid.c

   1 /******************************************************************************
   2  * vtoy_gen_uuid.c
   3  *
   4  * Copyright (c) 2020, longpanda <admin@ventoy.net>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; either version 3 of the
   9  * License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * 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, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <errno.h>
  25 #include <unistd.h>
  26 #include <fcntl.h>
  27
  28 int main()
  29 {
  30     int i;
  31     int fd;
  32     unsigned char uuid[16];
  33
  34     fd = open("/dev/random", O_RDONLY);
  35     if (fd < 0)
  36     {
  37         srand(time(NULL));
  38         for (i = 0; i < 16; i++)
  39         {
  40             uuid[i] = (unsigned char)(rand());
  41         }
  42     }
  43     else
  44     {
  45         read(fd, uuid, 16);
  46     }
  47
  48     fwrite(uuid, 1, 16, stdout);
  49     return 0;
  50 }