#include <sys/sysctl.h>

#include <errno.h>

#define	UV__ERR(errno)	errno
#define	UV_EIO		EIO
#define	ARRAY_SIZE(A)	(sizeof(A)/sizeof((A)[0]))

int uv__random_sysctl(void* buf, size_t len) {
  const int mib[] = {CTL_KERN, KERN_ARND};
  unsigned char *p = buf;

  while (len) {
    size_t nreq = MIN(len, 32), n = nreq;
    if (sysctl(mib, ARRAY_SIZE(mib), p, &n, NULL, 0) == -1)
      return UV__ERR(errno);
    if (n != nreq)
      return UV_EIO;		/* can't happen */
    p += n;
    len -= n;
  }

  return 0;
}

#include <assert.h>
#include <err.h>
#include <stdio.h>
#include <string.h>

int main(void) {
  unsigned char buf0[130], *buf = buf0 + 1; /* misalign */
  size_t i, j;
  int error;

  for (i = 0; i < 128; i++) {
    memset(buf0, 0, sizeof buf0);
    error = uv__random_sysctl(buf, i);
    if (error) {
      errno = error;
      err(1, "rando");
    }
    assert(buf0[0] == 0);
    assert(buf0[129] == 0);
    for (j = 0; j < i; j++)
      printf("%02hhx", buf[j]);
    printf("\n");
  }
  printf("ok\n");
  fflush(stdout);
  return ferror(stdout);
}