1 /*
2 * Copyright (C) 2015 Cedric Hnyda ced.hnyda@gmail.com
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of version 2 of the GNU General Public License as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it would be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
11 *
12 * Further, this software is distributed without any warranty that it is
13 * free of the rightful claim of any third person regarding infringement
14 * or the like. Any license provided herein, whether implied or
15 * otherwise, applies only to this software file. Patent licenses, if
16 * any, provided herein do not apply to combinations of this program with
17 * other software, or any other product whatsoever.
18 *
19 */
20
21 /*
22 * AUTHOR : Cédric Hnyda
23 * DATE STARTED : 06/13/2015
24 *
25 * Calls getrandom(2), checks that the buffer is filled with random bytes
26 * and expects success.
27 *
28 */
29
30 #include "lapi/getrandom.h"
31 #include "lapi/syscalls.h"
32 #include "tst_test.h"
33
34 static int modes[] = { 0, GRND_RANDOM, GRND_NONBLOCK,
35 GRND_RANDOM | GRND_NONBLOCK };
36
check_content(unsigned char * buf,int nb)37 static int check_content(unsigned char *buf, int nb)
38 {
39 int table[256];
40 int i, index, max;
41
42 memset(table, 0, sizeof(table));
43
44 max = 6 + nb * 0.2;
45
46 for (i = 0; i < nb; i++) {
47 index = buf[i];
48 table[index]++;
49 }
50
51 for (i = 0; i < nb; i++) {
52 if (max > 0 && table[i] > max)
53 return 0;
54 }
55 return 1;
56 }
57
verify_getrandom(unsigned int n)58 static void verify_getrandom(unsigned int n)
59 {
60 unsigned char buf[256];
61
62 memset(buf, 0, sizeof(buf));
63
64 do {
65 TEST(tst_syscall(__NR_getrandom, buf, sizeof(buf), modes[n]));
66 } while ((modes[n] & GRND_NONBLOCK) && TST_RET == -1
67 && TST_ERR == EAGAIN);
68
69 if (!check_content(buf, TST_RET))
70 tst_res(TFAIL | TTERRNO, "getrandom failed");
71 else
72 tst_res(TPASS, "getrandom returned %ld", TST_RET);
73 }
74
75 static struct tst_test test = {
76 .tcnt = ARRAY_SIZE(modes),
77 .test = verify_getrandom,
78 };
79