lib/libsys/get_randomness.c

   1 #include <lib.h>
   2
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <minix/profile.h>
   6 #include <minix/syslib.h>
   7 #include <minix/type.h>
   8 #include <minix/minlib.h>
   9 #include <minix/sysutil.h>
  10
  11 /*===========================================================================*
  12  *                              get_randomness                               *
  13  *===========================================================================*/
  14 void get_randomness(rand, source)
  15 struct k_randomness *rand;
  16 int source;
  17 {
  18 /* Use architecture-dependent high-resolution clock for
  19  * raw entropy gathering.
  20  */
  21   int r_next;
  22   unsigned long tsc_high, tsc_low;
  23
  24   source %= RANDOM_SOURCES;
  25   r_next= rand->bin[source].r_next;
  26   read_tsc((u32_t *) &tsc_high, (u32_t *) &tsc_low);
  27   rand->bin[source].r_buf[r_next] = tsc_low;
  28   if (rand->bin[source].r_size < RANDOM_ELEMENTS) {
  29         rand->bin[source].r_size ++;
  30   }
  31   rand->bin[source].r_next = (r_next + 1 ) % RANDOM_ELEMENTS;
  32 }
  33
  34