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
188
189
|
// Copyright (c) 2006, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "common/linux/eintr_wrapper.h"
#include "common/linux/guid_creator.h"
#include <assert.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <time.h>
#include <unistd.h>
#if defined(HAVE_SYS_RANDOM_H)
#include <sys/random.h>
#endif
//
// GUIDGenerator
//
// This class is used to generate random GUID.
// Currently use random number to generate a GUID since Linux has
// no native GUID generator. This should be OK since we don't expect
// crash to happen very offen.
//
class GUIDGenerator {
public:
static uint32_t BytesToUInt32(const uint8_t bytes[]) {
return ((uint32_t) bytes[0]
| ((uint32_t) bytes[1] << 8)
| ((uint32_t) bytes[2] << 16)
| ((uint32_t) bytes[3] << 24));
}
static void UInt32ToBytes(uint8_t bytes[], uint32_t n) {
bytes[0] = n & 0xff;
bytes[1] = (n >> 8) & 0xff;
bytes[2] = (n >> 16) & 0xff;
bytes[3] = (n >> 24) & 0xff;
}
static bool CreateGUID(GUID *guid) {
#if defined(HAVE_ARC4RANDOM) // Android, BSD, ...
CreateGuidFromArc4Random(guid);
#else // Linux
bool success = false;
#if defined(HAVE_SYS_RANDOM_H) && defined(HAVE_GETRANDOM)
success = CreateGUIDFromGetrandom(guid);
#endif // HAVE_SYS_RANDOM_H && HAVE_GETRANDOM
if (!success) {
success = CreateGUIDFromDevUrandom(guid);
}
if (!success) {
CreateGUIDFromRand(guid);
success = true;
}
#endif
// Put in the version according to RFC 4122.
guid->data3 &= 0x0fff;
guid->data3 |= 0x4000;
// Put in the variant according to RFC 4122.
guid->data4[0] &= 0x3f;
guid->data4[0] |= 0x80;
return true;
}
private:
#ifdef HAVE_ARC4RANDOM
static void CreateGuidFromArc4Random(GUID *guid) {
char *buf = reinterpret_cast<char *>(guid);
for (size_t i = 0; i < sizeof(GUID); i += sizeof(uint32_t)) {
uint32_t random_data = arc4random();
memcpy(buf + i, &random_data, sizeof(uint32_t));
}
}
#else
static void InitOnce() {
pthread_once(&once_control, &InitOnceImpl);
}
static void InitOnceImpl() {
// time(NULL) is a very poor seed, so lacking anything better mix an
// address into it. We drop the four rightmost bits as they're likely to
// be 0 on almost all architectures.
srand(time(NULL) | ((uintptr_t)&once_control >> 4));
}
static pthread_once_t once_control;
#if defined(HAVE_SYS_RANDOM_H) && defined(HAVE_GETRANDOM)
static bool CreateGUIDFromGetrandom(GUID *guid) {
char *buf = reinterpret_cast<char *>(guid);
int read_bytes = getrandom(buf, sizeof(GUID), GRND_NONBLOCK);
return (read_bytes == static_cast<int>(sizeof(GUID)));
}
#endif // HAVE_SYS_RANDOM_H && HAVE_GETRANDOM
// Populate the GUID using random bytes read from /dev/urandom, returns false
// if the GUID wasn't fully populated with random data.
static bool CreateGUIDFromDevUrandom(GUID *guid) {
char *buf = reinterpret_cast<char *>(guid);
int fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC);
if (fd == -1) {
return false;
}
ssize_t read_bytes = HANDLE_EINTR(read(fd, buf, sizeof(GUID)));
close(fd);
return (read_bytes == static_cast<ssize_t>(sizeof(GUID)));
}
// Populate the GUID using a stream of random bytes obtained from rand().
static void CreateGUIDFromRand(GUID *guid) {
char *buf = reinterpret_cast<char *>(guid);
InitOnce();
for (size_t i = 0; i < sizeof(GUID); i++) {
buf[i] = rand();
}
}
#endif
};
#ifndef HAVE_ARC4RANDOM
pthread_once_t GUIDGenerator::once_control = PTHREAD_ONCE_INIT;
#endif
bool CreateGUID(GUID *guid) {
return GUIDGenerator::CreateGUID(guid);
}
// Parse guid to string.
bool GUIDToString(const GUID *guid, char *buf, int buf_len) {
// Should allow more space the the max length of GUID.
assert(buf_len > kGUIDStringLength);
int num = snprintf(buf, buf_len, kGUIDFormatString,
guid->data1, guid->data2, guid->data3,
GUIDGenerator::BytesToUInt32(&(guid->data4[0])),
GUIDGenerator::BytesToUInt32(&(guid->data4[4])));
if (num != kGUIDStringLength)
return false;
buf[num] = '\0';
return true;
}
|
