Paparazzi UAS  v5.15_devel-99-g2ff7410
Paparazzi is a free software Unmanned Aircraft System.
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rng_arch.c
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1 /*
2  * Copyright (C) 2017 Michal Podhradsky <mpodhradsky@galois.com>
3  *
4  * This file is part of Paparazzi.
5  *
6  * Paparazzi is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2, or (at your option)
9  * any later version.
10  *
11  * Paparazzi is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with Paparazzi; see the file COPYING. If not, write to
18  * the Free Software Foundation, 59 Temple Place - Suite 330,
19  * Boston, MA 02111-1307, USA.
20  *
21  */
22 
27 #include "mcu_periph/rng.h"
28 
29 #include <fcntl.h>
30 #include <unistd.h>
31 #include <stdlib.h>
32 #include <stdio.h>
33 
34 void rng_init(void) {}
35 
36 void rng_deinit(void) {}
37 
38 // Return true only if we got a new number
39 // that is different from the previous one
40 bool rng_get(uint32_t *rand_nr)
41 {
42  int fd = open("/dev/urandom", O_RDONLY);
43  if (fd == -1) {
44  printf("Cannot open /dev/urandom\n");
45  return false;
46  }
47 
48  uint8_t len = sizeof(uint32_t);
49  uint8_t res = read(fd, rand_nr, len);
50  if (res != len) {
51  printf("Error on reading, expected %u bytes, got %u bytes\n",
52  len, res);
53  return false;
54  }
55  close(fd);
56  return true;
57 }
58 
59 // Wait until we get a new number that is different
60 // from the previous one. We can wait forever here if
61 // the clocks are not setup properly.
63  uint32_t tmp = 0;
64  while (!rng_get(&tmp)) {};
65  return tmp;
66 }
bool rng_get(uint32_t *rand_nr)
Definition: rng_arch.c:40
unsigned long uint32_t
Definition: types.h:18
void rng_deinit(void)
Definition: rng_arch.c:36
void rng_init(void)
Definition: rng_arch.c:34
arch independent Random Number Generator API
unsigned char uint8_t
Definition: types.h:14
uint32_t rng_wait_and_get(void)
Definition: rng_arch.c:62
int fd
Definition: serial.c:26