src/misc/getentropy.c

   1 #define _BSD_SOURCE
   2 #include <unistd.h>
   3 #include <sys/random.h>
   4 #include <pthread.h>
   5 #include <errno.h>
   6
   7 int getentropy(void *buffer, size_t len)
   8 {
   9         int cs, ret = 0;
  10         char *pos = buffer;
  11
  12         if (len > 256) {
  13                 errno = EIO;
  14                 return -1;
  15         }
  16
  17         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
  18
  19         while (len) {
  20                 ret = getrandom(pos, len, 0);
  21                 if (ret < 0) {
  22                         if (errno == EINTR) continue;
  23                         else break;
  24                 }
  25                 pos += ret;
  26                 len -= ret;
  27                 ret = 0;
  28         }
  29
  30         pthread_setcancelstate(cs, 0);
  31
  32         return ret;
  33 }