1 /* Test of getting random bytes.
2 Copyright (C) 2020 Free Software Foundation, Inc.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <https://www.gnu.org/licenses/>. */
16
17 /* Written by Bruno Haible. */
18
19 #include <config.h>
20
21 #include <sys/random.h>
22
23 #include "signature.h"
24 SIGNATURE_CHECK (getrandom, ssize_t, (void *, size_t, unsigned int));
25
26 #include <errno.h>
27 #include <string.h>
28
29 #include "macros.h"
30
31 int
main(void)32 main (void)
33 {
34 char buf1[8];
35 char buf2[8];
36 char large_buf[100000];
37 ssize_t ret;
38
39 /* Check that different calls produce different results (with a high
40 probability). */
41 ret = getrandom (buf1, sizeof (buf1), 0);
42 if (ret < 0)
43 ASSERT (errno == ENOSYS);
44 else
45 {
46 ret = getrandom (buf2, sizeof (buf2), 0);
47 if (ret < 0)
48 ASSERT (errno == ENOSYS);
49 else
50 {
51 /* It is very unlikely that two calls to getrandom produce the
52 same results. */
53 ASSERT (memcmp (buf1, buf2, sizeof (buf1)) != 0);
54 }
55 }
56
57 /* Likewise with the "truly random" number generator. */
58 ret = getrandom (buf1, sizeof (buf1), GRND_RANDOM);
59 if (ret < 0)
60 ASSERT (errno == ENOSYS);
61 else
62 {
63 ret = getrandom (buf2, sizeof (buf2), GRND_RANDOM);
64 if (ret < 0)
65 ASSERT (errno == ENOSYS);
66 else
67 {
68 /* It is very unlikely that two calls to getrandom produce the
69 same results. */
70 ASSERT (memcmp (buf1, buf2, sizeof (buf1)) != 0);
71 }
72 }
73
74 /* Check that GRND_NONBLOCK works. */
75 ret = getrandom (large_buf, sizeof (large_buf), GRND_RANDOM | GRND_NONBLOCK);
76 ASSERT (ret <= (ssize_t) sizeof (large_buf));
77 /* It is very unlikely that so many truly random bytes were ready. */
78 if (ret < 0)
79 ASSERT (errno == ENOSYS || errno == EAGAIN
80 || errno == EINVAL /* Solaris */);
81 else
82 ASSERT (ret > 0);
83
84 if (getrandom (buf1, 1, 0) < 1)
85 if (getrandom (buf1, 1, GRND_RANDOM) < 1)
86 {
87 fputs ("Skipping test: getrandom is ineffective\n", stderr);
88 return 77;
89 }
90
91 return 0;
92 }
93