trezor-firmware/core/embed/unix/rng.c

/*
 * This file is part of the TREZOR project, https://trezor.io/
 *
 * Copyright (c) SatoshiLabs
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <stdlib.h>

#include "common.h"
#include "rng.h"

uint32_t rng_get(void) {
  static FILE *frand = NULL;
  if (!frand) {
    frand = fopen("/dev/urandom", "r");
  }
  ensure(sectrue * (frand != NULL), "fopen failed");
  uint32_t r;
  ensure(sectrue * (sizeof(r) == fread(&r, 1, sizeof(r), frand)),
         "fread failed");
  return r;
}