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
|
// **********************************************************************
//
// Copyright (c) 2003
// ZeroC, Inc.
// Billerica, MA, USA
//
// All Rights Reserved.
//
// Ice is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License version 2 as published by
// the Free Software Foundation.
//
// **********************************************************************
#include <IceUtil/UUID.h>
// On Windows, we use Windows's RPC UUID generator.
// On other platforms, we use a high quality random number generator
// (/dev/random) to generate "version 4" UUIDs, as described in
// http://www.ietf.org/internet-drafts/draft-mealling-uuid-urn-00.txt
#ifdef _WIN32
# include <rpc.h>
#else
#include <sys/types.h>
# include <sys/stat.h>
# include <fcntl.h>
# include <unistd.h>
#endif
using namespace std;
// Helper char to hex functions
//
inline void halfByteToHex(unsigned char hb, char*& hexBuffer)
{
if(hb < 10)
{
*hexBuffer++ = '0' + hb;
}
else
{
*hexBuffer++ = 'A' + (hb - 10);
}
}
inline void bytesToHex(unsigned char* bytes, size_t len, char*& hexBuffer)
{
for(size_t i = 0; i < len; i++)
{
halfByteToHex((bytes[i] & 0xF0) >> 4, hexBuffer);
halfByteToHex((bytes[i] & 0x0F), hexBuffer);
}
}
IceUtil::UUIDGenerationException::UUIDGenerationException(const char* file, int line) :
Exception(file, line)
{
}
string
IceUtil::UUIDGenerationException::ice_name() const
{
return "IceUtil::UUIDGenerationException";
}
IceUtil::Exception*
IceUtil::UUIDGenerationException::ice_clone() const
{
return new UUIDGenerationException(*this);
}
void
IceUtil::UUIDGenerationException::ice_throw() const
{
throw *this;
}
string
IceUtil::generateUUID()
{
#ifdef _WIN32
UUID uuid;
UuidCreate(&uuid);
unsigned char* str;
UuidToString(&uuid, &str);
string result = reinterpret_cast<char*>(str);
RpcStringFree(&str);
return result;
#else
// On Linux, /dev/random, even when used in blocking mode, sometimes
// fails or returns fewer bytes.
// Maybe we should use a combination of version 4 UUIDs (with /dev/random),
// and version 1 UUIDs (MAC address + time), when /dev/random is exhausted?
int fd = open("/dev/urandom", O_RDONLY);
if (fd == -1)
{
assert(0);
throw UUIDGenerationException(__FILE__, __LINE__);
}
struct UUID
{
unsigned char timeLow[4];
unsigned char timeMid[2];
unsigned char timeHighAndVersion[2];
unsigned char clockSeqHiAndReserved;
unsigned char clockSeqLow;
unsigned char node[6];
};
UUID uuid;
assert(sizeof(UUID) == 16);
char* buffer = reinterpret_cast<char*>(&uuid);
int reads = 0;
size_t index = 0;
// Limit the number of attempts to 20 reads to avoid
// a potential "for ever" loop
//
while(reads <= 20 && index != sizeof(UUID))
{
ssize_t bytesRead = read(fd, buffer + index, sizeof(UUID) - index);
if(bytesRead == -1 && errno != EINTR)
{
int err = errno;
cerr << "Reading /dev/urandom returned " << strerror(err) << endl;
assert(0);
close(fd);
throw UUIDGenerationException(__FILE__, __LINE__);
}
else
{
index += bytesRead;
reads++;
}
}
if (index != sizeof(UUID))
{
assert(0);
close(fd);
throw UUIDGenerationException(__FILE__, __LINE__);
}
close(fd);
// Adjust the bits that say "version 4" UUID
//
uuid.timeHighAndVersion[0] &= 0x0F;
uuid.timeHighAndVersion[0] |= (4 << 4);
uuid.clockSeqHiAndReserved &= 0x3F;
uuid.clockSeqHiAndReserved |= 0x80;
// Convert to a UUID string
//
char uuidString[16 * 2 + 4 + 1]; // 16 bytes, 4 '-' and a final '\0'
char* uuidIndex = uuidString;
bytesToHex(uuid.timeLow, sizeof(uuid.timeLow), uuidIndex);
*uuidIndex++ = '-';
bytesToHex(uuid.timeMid, sizeof(uuid.timeMid), uuidIndex);
*uuidIndex++ = '-';
bytesToHex(uuid.timeHighAndVersion, sizeof(uuid.timeHighAndVersion), uuidIndex);
*uuidIndex++ = '-';
bytesToHex(&uuid.clockSeqHiAndReserved, sizeof(uuid.clockSeqHiAndReserved), uuidIndex);
bytesToHex(&uuid.clockSeqLow, sizeof(uuid.clockSeqLow), uuidIndex);
*uuidIndex++ = '-';
bytesToHex(uuid.node, sizeof(uuid.node), uuidIndex);
*uuidIndex = '\0';
return uuidString;
#endif
}
|
