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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
|
/*
libminuid - minimalistic globally unique IDs
Copyright (C) 2017 Tibor 'Igor2' Palinkas
This library 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 2.1 of the License, or (at your option) any later version.
This library 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 this library; if not, write to the Free Software
Foundation, Inc., 31 Milk Street, # 960789 Boston, MA 02196 USA
Project page: http://repo.hu/projects/libminuid
Source code: svn://repo.hu/libminuid/trunk
Author: emailto: libminuid [at] igor2.repo.hu
*/
#include <stdio.h>
#include <time.h>
#include <string.h>
#include "libminuid.h"
#include "base64.h"
minuid_bin_t minuid_nil;
int minuid_salt(minuid_session_t *sess, const void *salt, int salt_len)
{
const char *s;
if (salt_len <= 0)
return -1;
for(s = salt; salt_len > 0; s++, salt_len--) {
sess->sid[sess->salt_offs] ^= *s;
sess->salt_offs++;
if (sess->salt_offs >= MINUID_SID_LEN)
sess->salt_offs = 0;
}
return 0;
}
/* Salt from a file, typically a device file like /dev/urandom on *NIX */
static int try_file_salt(minuid_session_t *sess, char *fn)
{
FILE *f;
unsigned char buff[MINUID_SID_LEN];
int len;
f = fopen(fn, "rb");
if (f == NULL)
return 0;
len = fread(buff, 1, MINUID_SID_LEN, f);
fclose(f);
if (len > 0)
minuid_salt(sess, buff, len);
return len > 2 * MINUID_SID_LEN / 3;
}
/* salt from pseudorandom */
static int try_time_salt(minuid_session_t *sess)
{
time_t t = time(NULL);
minuid_salt(sess, &t, sizeof(t));
return 0;
}
/* Create a new session in sess */
int minuid_init(minuid_session_t *sess)
{
memset(sess, 0, sizeof(minuid_session_t));
(void)(try_file_salt(sess, "/dev/urandom") || try_file_salt(sess, "/dev/random") || try_time_salt(sess));
return 0;
}
int minuid_gen(minuid_session_t *sess, minuid_bin_t dst)
{
unsigned char *d;
sess->seqno++;
if (sess->seqno == 0) {
/* overflow; bump sid */
static unsigned char ovf = 1;
try_time_salt(sess);
minuid_salt(sess, &ovf, sizeof(ovf)); /* just in case time was 0 */
ovf++;
}
d = (unsigned char *)dst;
memcpy(d, sess->sid, MINUID_SID_LEN);
d += MINUID_SID_LEN;
*d++ = ((sess->seqno & 0xFF000000UL) >> 24);
*d++ = ((sess->seqno & 0x00FF0000UL) >> 16);
*d++ = ((sess->seqno & 0x0000FF00UL) >> 8);
*d++ = (sess->seqno & 0x000000FFUL);
return 0;
}
int minuid_cmp(const minuid_bin_t u1, const minuid_bin_t u2)
{
return memcmp(u1, u2, sizeof(minuid_bin_t));
}
void minuid_cpy(minuid_bin_t dst, const minuid_bin_t src)
{
memcpy(dst, src, sizeof(minuid_bin_t));
}
void minuid_swap(minuid_bin_t a, const minuid_bin_t b)
{
unsigned char tmp, *s1 = (unsigned char *)a, *s2 = (unsigned char *)b;
int n;
for(n = 0; n < sizeof(minuid_bin_t); n++,s1++,s2++) {
tmp = *s1;
*s1 = *s2;
*s2 = tmp;
}
}
int minuid_bin2str(minuid_str_t dst, const minuid_bin_t src)
{
const unsigned char *s_begin = (const unsigned char *)src;
const unsigned char *s_end = s_begin + sizeof(minuid_bin_t) - 1, *s;
char *d = (char *)dst + sizeof(minuid_str_t) - 1;
unsigned int dig, acc = 0, bits = 0;
*d-- = '\0';
for(s = s_end; (s >= s_begin) || (bits > 0); d--) {
/* shift in the next 6 bits */
if (bits < 6) {
acc |= ((unsigned int)*s) << bits;
bits += 8;
s--;
}
dig = acc & 0x3F;
acc >>= 6;
bits -= 6;
*d = MINUID_BASE64_I2C[dig];
}
return 0;
}
int minuid_str2bin(minuid_bin_t dst, const minuid_str_t src)
{
unsigned char *d_begin = (unsigned char *)dst;
unsigned char *d_end = d_begin + sizeof(minuid_bin_t) - 1, *d;
const char *s = (const char *)src + sizeof(minuid_str_t) - 1;
const char *s_begin = (const char *)src;
unsigned int acc = 0, bits = 0;
int dig;
if (*s != '\0')
return -1;
s--;
for(d = d_end; (s >= s_begin) || (bits > 0); d--) {
while(bits < 8) {
dig = MINUID_BASE64_C2I[(int)*s];
if (dig < 0)
return -1;
acc |= ((unsigned int)(dig))<<bits;
bits += 6;
s--;
}
*d = acc & 0xFF;
acc >>= 8;
bits -= 8;
}
return 0;
}
|
