1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
/*
* Copyright(c) 2012 Tim Ruehsen
* Copyright(c) 2016-2018 Free Software Foundation, Inc.
*
* This file is part of libwget.
*
* Libwget is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Libwget 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with libwget. If not, see <https://www.gnu.org/licenses/>.
*
*
* a multi-thread safe wrapper around gnulib random_r()
*
* Changelog
* 22.01.2016 Tim Ruehsen created
*
*/
#include <config.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#ifdef _WIN32
# include <process.h> /* getpid() */
#endif
#include <wget.h>
#include "private.h"
/**
* \file
* \brief Random functions
* \defgroup libwget-random Random functions
* @{
*
* This is wrapper code around gnulib's srandom_r() and random_r() with automatic seeding
*/
static int seeded;
static char statebuf[64];
static struct random_data state;
static wget_thread_mutex_t mutex;
static bool initialized;
static void __attribute__ ((constructor)) _wget_random_init(void)
{
if (!initialized) {
wget_thread_mutex_init(&mutex);
initialized = 1;
}
}
static void __attribute__ ((destructor)) _wget_random_exit(void)
{
if (initialized) {
wget_thread_mutex_destroy(&mutex);
initialized = 0;
}
}
/**
* Random API initialization, allocating/preparing the internal resources.
*
* On systems with automatic library constructors, this function
* doesn't have to be called explictly.
*
* This function is not thread-safe.
*/
void wget_random_init(void)
{
_wget_random_init();
}
/**
* Random API deinitialization, free'ing all internal resources.
*
* On systems with automatic library destructors, this function
* doesn't have to be called explictly.
*
* This function is not thread-safe.
*/
void wget_random_exit(void)
{
_wget_random_exit();
}
/**
* \return Random value between 0 and RAND_MAX
*
* This functions wraps around gnulib's random_r(). It performs a thread-safe seeding on the first use,
* if not done before by wget_srandom();
*/
int wget_random(void)
{
int32_t r;
wget_thread_mutex_lock(mutex);
if (!seeded) {
// seed random generator, used e.g. by Digest Authentication and --random-wait
initstate_r((unsigned)(time(NULL) ^ getpid()), statebuf, sizeof(statebuf), &state);
seeded = 1;
}
if (random_r(&state, &r))
r = 0; // return 0 on failure
wget_thread_mutex_unlock(mutex);
return (int)r;
}
/**
* \param[in] seed Value to seed the random generator
*
* This functions wraps around srandom_r() to make a thread-safe seeding for wget_random().
*/
void wget_srandom(unsigned int seed)
{
wget_thread_mutex_lock(mutex);
initstate_r(seed, statebuf, sizeof(statebuf), &state);
seeded = 1;
wget_thread_mutex_unlock(mutex);
}
/**@}*/
|
