1 /*
2 * gen_uuid.c --- generate a DCE-compatible uuid
3 *
4 * Copyright (C) 1996, 1997, 1998, 1999 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, and the entire permission notice in its entirety,
12 * including the disclaimer of warranties.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote
17 * products derived from this software without specific prior
18 * written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
21 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
23 * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
24 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
26 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
27 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
28 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
30 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
31 * DAMAGE.
32 * %End-Header%
33 */
34
35 #include <stdio.h>
36 #include <unistd.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <fcntl.h>
40 #include <errno.h>
41 #include <sys/types.h>
42 #include <sys/time.h>
43 #include <sys/wait.h>
44 #include <sys/stat.h>
45 #include <sys/file.h>
46 #include <sys/ioctl.h>
47 #include <sys/socket.h>
48 #include <sys/un.h>
49 #include <sys/sockio.h>
50 #include <net/if.h>
51 #include <netinet/in.h>
52 #include <net/if_dl.h>
53 #include <sys/resource.h>
54
55 #include "uuidP.h"
56
57 #ifdef HAVE_SRANDOM
58 #define srand(x) srandom(x)
59 #define rand() random()
60 #endif
61
62 #ifdef TLS
63 #define THREAD_LOCAL static TLS
64 #else
65 #define THREAD_LOCAL static
66 #endif
67
68 #if defined(__linux__) && defined(__NR_gettid) && defined(HAVE_JRAND48)
69 #define DO_JRAND_MIX
70 THREAD_LOCAL unsigned short jrand_seed[3];
71 #endif
72
get_random_fd(void)73 static int get_random_fd(void)
74 {
75 struct timeval tv;
76 static int fd = -2;
77 int i;
78
79 if (fd == -2) {
80 gettimeofday(&tv, 0);
81 fd = open("/dev/urandom", O_RDONLY);
82 if (fd == -1)
83 fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
84 if (fd >= 0) {
85 i = fcntl(fd, F_GETFD);
86 if (i >= 0)
87 fcntl(fd, F_SETFD, i | FD_CLOEXEC);
88 }
89 srand((getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
90 #ifdef DO_JRAND_MIX
91 jrand_seed[0] = getpid() ^ (tv.tv_sec & 0xFFFF);
92 jrand_seed[1] = getppid() ^ (tv.tv_usec & 0xFFFF);
93 jrand_seed[2] = (tv.tv_sec ^ tv.tv_usec) >> 16;
94 #endif
95 }
96 /* Crank the random number generator a few times */
97 gettimeofday(&tv, 0);
98 for (i = (tv.tv_sec ^ tv.tv_usec) & 0x1F; i > 0; i--)
99 rand();
100 return fd;
101 }
102
103
104 /*
105 * Generate a series of random bytes. Use /dev/urandom if possible,
106 * and if not, use srandom/random.
107 */
get_random_bytes(void * buf,int nbytes)108 static void get_random_bytes(void *buf, int nbytes)
109 {
110 int i, n = nbytes, fd = get_random_fd();
111 int lose_counter = 0;
112 unsigned char *cp = buf;
113
114 if (fd >= 0) {
115 while (n > 0) {
116 i = read(fd, cp, n);
117 if (i <= 0) {
118 if (lose_counter++ > 16)
119 break;
120 continue;
121 }
122 n -= i;
123 cp += i;
124 lose_counter = 0;
125 }
126 }
127
128 /*
129 * We do this all the time, but this is the only source of
130 * randomness if /dev/random/urandom is out to lunch.
131 */
132 for (cp = buf, i = 0; i < nbytes; i++)
133 *cp++ ^= (rand() >> 7) & 0xFF;
134 #ifdef DO_JRAND_MIX
135 {
136 unsigned short tmp_seed[3];
137
138 memcpy(tmp_seed, jrand_seed, sizeof(tmp_seed));
139 jrand_seed[2] = jrand_seed[2] ^ syscall(__NR_gettid);
140 for (cp = buf, i = 0; i < nbytes; i++)
141 *cp++ ^= (jrand48(tmp_seed) >> 7) & 0xFF;
142 memcpy(jrand_seed, tmp_seed,
143 sizeof(jrand_seed) - sizeof(unsigned short));
144 }
145 #endif
146
147 return;
148 }
149
150 #ifndef _KERNEL_MODE
151 /*
152 * Get the ethernet hardware address, if we can find it...
153 *
154 * XXX for a windows version, probably should use GetAdaptersInfo:
155 * http://www.codeguru.com/cpp/i-n/network/networkinformation/article.php/c5451
156 * commenting out get_node_id just to get gen_uuid to compile under windows
157 * is not the right way to go!
158 */
get_node_id(unsigned char * node_id)159 static int get_node_id(unsigned char *node_id)
160 {
161 int sd;
162 struct ifreq ifr, *ifrp;
163 struct ifconf ifc;
164 char buf[1024];
165 int n, i;
166 unsigned char *a;
167 struct sockaddr_dl *sdlp;
168
169 /*
170 * BSD 4.4 defines the size of an ifreq to be
171 * max(sizeof(ifreq), sizeof(ifreq.ifr_name)+ifreq.ifr_addr.sa_len
172 * However, under earlier systems, sa_len isn't present, so the size is
173 * just sizeof(struct ifreq)
174 */
175 #ifndef max
176 #define max(a,b) ((a) > (b) ? (a) : (b))
177 #endif
178 #define ifreq_size(i) max(sizeof(struct ifreq),\
179 sizeof((i).ifr_name)+(i).ifr_addr.sa_len)
180
181 sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
182 if (sd < 0) {
183 return -1;
184 }
185 memset(buf, 0, sizeof(buf));
186 ifc.ifc_len = sizeof(buf);
187 ifc.ifc_buf = buf;
188 if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) {
189 close(sd);
190 return -1;
191 }
192 n = ifc.ifc_len;
193 for (i = 0; i < n; i+= ifreq_size(*ifrp) ) {
194 ifrp = (struct ifreq *)((char *) ifc.ifc_buf+i);
195 strncpy(ifr.ifr_name, ifrp->ifr_name, IFNAMSIZ);
196 #ifdef SIOCGIFHWADDR
197 if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)
198 continue;
199 a = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
200 #else
201 #ifdef SIOCGENADDR
202 if (ioctl(sd, SIOCGENADDR, &ifr) < 0)
203 continue;
204 a = (unsigned char *) ifr.ifr_enaddr;
205 #else
206 sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr;
207 if ((sdlp->sdl_family != AF_LINK) || (sdlp->sdl_alen != 6))
208 continue;
209 a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen];
210 #endif /* SIOCGENADDR */
211 #endif /* SIOCGIFHWADDR */
212 if (!a[0] && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
213 continue;
214 if (node_id) {
215 memcpy(node_id, a, 6);
216 close(sd);
217 return 1;
218 }
219 }
220 close(sd);
221 return 0;
222 }
223
224 /* Assume that the gettimeofday() has microsecond granularity */
225 #define MAX_ADJUSTMENT 10
226
get_clock(uint32_t * clock_high,uint32_t * clock_low,uint16_t * ret_clock_seq,int * num)227 static int get_clock(uint32_t *clock_high, uint32_t *clock_low,
228 uint16_t *ret_clock_seq, int *num)
229 {
230 THREAD_LOCAL int adjustment = 0;
231 THREAD_LOCAL struct timeval last = {0, 0};
232 THREAD_LOCAL int state_fd = -2;
233 THREAD_LOCAL FILE *state_f;
234 THREAD_LOCAL uint16_t clock_seq;
235 struct timeval tv;
236 struct flock fl;
237 uint64_t clock_reg;
238 mode_t save_umask;
239 int len;
240
241 if (state_fd == -2) {
242 save_umask = umask(0);
243 state_fd = open("/var/lib/libuuid/clock.txt",
244 O_RDWR|O_CREAT, 0660);
245 (void) umask(save_umask);
246 if (state_fd >= 0) {
247 state_f = fdopen(state_fd, "r+");
248 if (!state_f) {
249 close(state_fd);
250 state_fd = -1;
251 }
252 }
253 }
254 fl.l_type = F_WRLCK;
255 fl.l_whence = SEEK_SET;
256 fl.l_start = 0;
257 fl.l_len = 0;
258 fl.l_pid = 0;
259 if (state_fd >= 0) {
260 rewind(state_f);
261 while (fcntl(state_fd, F_SETLKW, &fl) < 0) {
262 if ((errno == EAGAIN) || (errno == EINTR))
263 continue;
264 fclose(state_f);
265 state_fd = -1;
266 break;
267 }
268 }
269 if (state_fd >= 0) {
270 unsigned int cl;
271 unsigned long tv1, tv2;
272 int a;
273
274 if (fscanf(state_f, "clock: %04x tv: %lu %lu adj: %d\n",
275 &cl, &tv1, &tv2, &a) == 4) {
276 clock_seq = cl & 0x3FFF;
277 last.tv_sec = tv1;
278 last.tv_usec = tv2;
279 adjustment = a;
280 }
281 }
282
283 if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
284 get_random_bytes(&clock_seq, sizeof(clock_seq));
285 clock_seq &= 0x3FFF;
286 gettimeofday(&last, 0);
287 last.tv_sec--;
288 }
289
290 try_again:
291 gettimeofday(&tv, 0);
292 if ((tv.tv_sec < last.tv_sec) ||
293 ((tv.tv_sec == last.tv_sec) &&
294 (tv.tv_usec < last.tv_usec))) {
295 clock_seq = (clock_seq+1) & 0x3FFF;
296 adjustment = 0;
297 last = tv;
298 } else if ((tv.tv_sec == last.tv_sec) &&
299 (tv.tv_usec == last.tv_usec)) {
300 if (adjustment >= MAX_ADJUSTMENT)
301 goto try_again;
302 adjustment++;
303 } else {
304 adjustment = 0;
305 last = tv;
306 }
307
308 clock_reg = tv.tv_usec*10 + adjustment;
309 clock_reg += ((uint64_t) tv.tv_sec)*10000000;
310 clock_reg += (((uint64_t) 0x01B21DD2) << 32) + 0x13814000;
311
312 if (num && (*num > 1)) {
313 adjustment += *num - 1;
314 last.tv_usec += adjustment / 10;
315 adjustment = adjustment % 10;
316 last.tv_sec += last.tv_usec / 1000000;
317 last.tv_usec = last.tv_usec % 1000000;
318 }
319
320 if (state_fd > 0) {
321 rewind(state_f);
322 len = fprintf(state_f,
323 "clock: %04x tv: %016lu %08lu adj: %08d\n",
324 clock_seq, last.tv_sec, (long)last.tv_usec,
325 adjustment);
326 fflush(state_f);
327 if (ftruncate(state_fd, len) < 0) {
328 fprintf(state_f, " \n");
329 fflush(state_f);
330 }
331 rewind(state_f);
332 fl.l_type = F_UNLCK;
333 if (fcntl(state_fd, F_SETLK, &fl) < 0) {
334 fclose(state_f);
335 state_fd = -1;
336 }
337 }
338
339 *clock_high = clock_reg >> 32;
340 *clock_low = clock_reg;
341 *ret_clock_seq = clock_seq;
342 return 0;
343 }
344
uuid__generate_time(uuid_t out,int * num)345 void uuid__generate_time(uuid_t out, int *num)
346 {
347 static unsigned char node_id[6];
348 static int has_init = 0;
349 struct uuid uu;
350 uint32_t clock_mid;
351
352 if (!has_init) {
353 if (get_node_id(node_id) <= 0) {
354 get_random_bytes(node_id, 6);
355 /*
356 * Set multicast bit, to prevent conflicts
357 * with IEEE 802 addresses obtained from
358 * network cards
359 */
360 node_id[0] |= 0x01;
361 }
362 has_init = 1;
363 }
364 get_clock(&clock_mid, &uu.time_low, &uu.clock_seq, num);
365 uu.clock_seq |= 0x8000;
366 uu.time_mid = (uint16_t) clock_mid;
367 uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) | 0x1000;
368 memcpy(uu.node, node_id, 6);
369 uuid_pack(&uu, out);
370 }
371
uuid_generate_time(uuid_t out)372 void uuid_generate_time(uuid_t out)
373 {
374 #ifdef TLS
375 THREAD_LOCAL int num = 0;
376 THREAD_LOCAL struct uuid uu;
377 THREAD_LOCAL time_t last_time = 0;
378 time_t now;
379
380 if (num > 0) {
381 now = time(0);
382 if (now > last_time+1)
383 num = 0;
384 }
385 if (num <= 0) {
386 num = 1000;
387 if (-1 == 0) {
388 last_time = time(0);
389 uuid_unpack(out, &uu);
390 num--;
391 return;
392 }
393 num = 0;
394 }
395 if (num > 0) {
396 uu.time_low++;
397 if (uu.time_low == 0) {
398 uu.time_mid++;
399 if (uu.time_mid == 0)
400 uu.time_hi_and_version++;
401 }
402 num--;
403 uuid_pack(&uu, out);
404 return;
405 }
406 #else
407 if (-1 == 0)
408 return;
409 #endif
410
411 uuid__generate_time(out, 0);
412 }
413 #endif // !_KERNEL_MODE
414
uuid__generate_random(uuid_t out,int * num)415 void uuid__generate_random(uuid_t out, int *num)
416 {
417 uuid_t buf;
418 struct uuid uu;
419 int i, n;
420
421 if (!num || !*num)
422 n = 1;
423 else
424 n = *num;
425
426 for (i = 0; i < n; i++) {
427 get_random_bytes(buf, sizeof(buf));
428 uuid_unpack(buf, &uu);
429
430 uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
431 uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF)
432 | 0x4000;
433 uuid_pack(&uu, out);
434 out += sizeof(uuid_t);
435 }
436 }
437
uuid_generate_random(uuid_t out)438 void uuid_generate_random(uuid_t out)
439 {
440 int num = 1;
441 /* No real reason to use the daemon for random uuid's -- yet */
442
443 uuid__generate_random(out, &num);
444 }
445
446 /*
447 * Check whether good random source (/dev/random or /dev/urandom)
448 * is available.
449 */
have_random_source(void)450 static int have_random_source(void)
451 {
452 struct stat s;
453
454 return (!stat("/dev/random", &s) || !stat("/dev/urandom", &s));
455 }
456
457
458 #ifndef _KERNEL_MODE
459 /*
460 * This is the generic front-end to uuid_generate_random and
461 * uuid_generate_time. It uses uuid_generate_random only if
462 * /dev/urandom is available, since otherwise we won't have
463 * high-quality randomness.
464 */
uuid_generate(uuid_t out)465 void uuid_generate(uuid_t out)
466 {
467 if (have_random_source())
468 uuid_generate_random(out);
469 else
470 uuid_generate_time(out);
471 }
472 #else
uuid_generate(uuid_t out)473 void uuid_generate(uuid_t out)
474 {
475 uuid_generate_random(out);
476 }
477 #endif
478