Mercurial > projects > pwm

annotate rand-getrandom.c @ 25:616385fa1fd9

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Build common functions as a library that can be reused
author Guido Berhoerster <guido+pwm@berhoerster.name>
date Wed, 20 Sep 2017 23:57:51 +0200
parents 8768fbd09bc5
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
12
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
1 /*
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
2 * Copyright (C) 2017 Guido Berhoerster <guido+pwm@berhoerster.name>
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
3 *
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
4 * Permission is hereby granted, free of charge, to any person obtaining
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
5 * a copy of this software and associated documentation files (the
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
6 * "Software"), to deal in the Software without restriction, including
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
7 * without limitation the rights to use, copy, modify, merge, publish,
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
8 * distribute, sublicense, and/or sell copies of the Software, and to
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
9 * permit persons to whom the Software is furnished to do so, subject to
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
10 * the following conditions:
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
11 *
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
12 * The above copyright notice and this permission notice shall be included
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
13 * in all copies or substantial portions of the Software.
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
14 *
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
18 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
19 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
20 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
21 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
22 */
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
23
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
24 #include "compat.h"
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
25
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
26 #include <stdlib.h>
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
27 /* glibc and Solaris 11 */
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
28 #include <sys/random.h>
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
29
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
30 #include "rand.h"
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
31
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
32 #define RANDOM_CHUNK 256U
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
33
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
34 void
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
35 rand_buf(void *buf, size_t buf_size)
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
36 {
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
37 unsigned char *p = buf;
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
38 ssize_t nread;
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
39 size_t nsize = buf_size;
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
40
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
41 while (nsize > 0) {
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
42 nread = getrandom(p, nsize, 0);
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
43 if (nread < 0) {
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
44 if (errno == EINTR) {
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
45 continue;
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
46 }
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
47 err(1, "read");
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
48 }
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
49 nsize -= nread;
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
50 p += nread;
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
51 }
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
52 }
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
53
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
54 uint32_t
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
55 rand_random(void)
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
56 {
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
57 uint32_t r;
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
58
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
59 getrandom(r, sizeof (uint32_t), 0);
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
60
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
61 return (r);
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
62 }
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
63
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
64 /* random number between 0 and upper_bound - 1 without modulo bias */
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
65 uint32_t
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
66 rand_uniform(uint32_t upper_bound)
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
67 {
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
68 uint32_t r;
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
69 /* (2^32 - upper_bound) % upper_bound */
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
70 uint32_t threshold = -upper_bound % upper_bound;
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
71
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
72 do {
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
73 r = rand_random();
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
74 } while (r < threshold);
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
75
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
76 return (r % upper_bound);
8768fbd09bc5 Add generatepassword command to generate random passwords
Guido Berhoerster <guido+pwm@berhoerster.name>
parents:
diff changeset
77 }