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 /*
36 * Force inclusion of SVID stuff since we need it if we're compiling in
37 * gcc-wall wall mode
38 */
39 #define _SVID_SOURCE
40 #define _DEFAULT_SOURCE /* since glibc 2.20 _SVID_SOURCE is deprecated */
41
42 #include "config.h"
43
44 #ifdef _WIN32
45 #define _WIN32_WINNT 0x0500
46 #include <windows.h>
47 #define UUID MYUUID
48 #endif
49 #include <stdio.h>
50 #ifdef HAVE_UNISTD_H
51 #include <unistd.h>
52 #endif
53 #ifdef HAVE_STDLIB_H
54 #include <stdlib.h>
55 #endif
56 #include <string.h>
57 #include <fcntl.h>
58 #include <errno.h>
59 #include <sys/types.h>
60 #ifdef HAVE_SYS_TIME_H
61 #include <sys/time.h>
62 #endif
63 #ifdef HAVE_SYS_WAIT_H
64 #include <sys/wait.h>
65 #endif
66 #include <sys/stat.h>
67 #ifdef HAVE_SYS_FILE_H
68 #include <sys/file.h>
69 #endif
70 #ifdef HAVE_SYS_IOCTL_H
71 #include <sys/ioctl.h>
72 #endif
73 #ifdef HAVE_SYS_SOCKET_H
74 #include <sys/socket.h>
75 #endif
76 #ifdef HAVE_SYS_UN_H
77 #include <sys/un.h>
78 #endif
79 #ifdef HAVE_SYS_SOCKIO_H
80 #include <sys/sockio.h>
81 #endif
82 #ifdef HAVE_NET_IF_H
83 #include <net/if.h>
84 #endif
85 #ifdef HAVE_NETINET_IN_H
86 #include <netinet/in.h>
87 #endif
88 #ifdef HAVE_NET_IF_DL_H
89 #include <net/if_dl.h>
90 #endif
91 #if defined(__linux__) && defined(HAVE_SYS_SYSCALL_H)
92 #include <sys/syscall.h>
93 #endif
94 #ifdef HAVE_SYS_RESOURCE_H
95 #include <sys/resource.h>
96 #endif
97
98 #include "uuidP.h"
99 #include "uuidd.h"
100
101 #ifdef HAVE_SRANDOM
102 #define srand(x) srandom(x)
103 #define rand() random()
104 #endif
105
106 #ifdef TLS
107 #define THREAD_LOCAL static TLS
108 #else
109 #define THREAD_LOCAL static
110 #endif
111
112 #if defined(__linux__) && defined(__NR_gettid) && defined(HAVE_JRAND48)
113 #define DO_JRAND_MIX
114 THREAD_LOCAL unsigned short jrand_seed[3];
115 #endif
116
117 #ifdef _WIN32
118 #ifndef USE_MINGW
gettimeofday(struct timeval * tv,void * dummy)119 static void gettimeofday (struct timeval *tv, void *dummy)
120 {
121 FILETIME ftime;
122 uint64_t n;
123
124 GetSystemTimeAsFileTime (&ftime);
125 n = (((uint64_t) ftime.dwHighDateTime << 32)
126 + (uint64_t) ftime.dwLowDateTime);
127 if (n) {
128 n /= 10;
129 n -= ((369 * 365 + 89) * (uint64_t) 86400) * 1000000;
130 }
131
132 tv->tv_sec = n / 1000000;
133 tv->tv_usec = n % 1000000;
134 }
135 #endif
136 #endif
137
get_random_fd(void)138 static int get_random_fd(void)
139 {
140 struct timeval tv;
141 static int fd = -2;
142 int i;
143
144 if (fd == -2) {
145 gettimeofday(&tv, 0);
146 #ifndef _WIN32
147 fd = open("/dev/urandom", O_RDONLY);
148 if (fd == -1)
149 fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
150 if (fd >= 0) {
151 i = fcntl(fd, F_GETFD);
152 if (i >= 0)
153 fcntl(fd, F_SETFD, i | FD_CLOEXEC);
154 }
155 #endif
156 srand(((unsigned)getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
157 #ifdef DO_JRAND_MIX
158 jrand_seed[0] = getpid() ^ (tv.tv_sec & 0xFFFF);
159 jrand_seed[1] = getppid() ^ (tv.tv_usec & 0xFFFF);
160 jrand_seed[2] = (tv.tv_sec ^ tv.tv_usec) >> 16;
161 #endif
162 }
163 /* Crank the random number generator a few times */
164 gettimeofday(&tv, 0);
165 for (i = (tv.tv_sec ^ tv.tv_usec) & 0x1F; i > 0; i--)
166 rand();
167 return fd;
168 }
169
170
171 /*
172 * Generate a series of random bytes. Use /dev/urandom if possible,
173 * and if not, use srandom/random.
174 */
get_random_bytes(void * buf,int nbytes)175 static void get_random_bytes(void *buf, int nbytes)
176 {
177 int i, n = nbytes, fd = get_random_fd();
178 int lose_counter = 0;
179 unsigned char *cp = buf;
180
181 if (fd >= 0) {
182 while (n > 0) {
183 i = read(fd, cp, n);
184 if (i <= 0) {
185 if (lose_counter++ > 16)
186 break;
187 continue;
188 }
189 n -= i;
190 cp += i;
191 lose_counter = 0;
192 }
193 }
194
195 /*
196 * We do this all the time, but this is the only source of
197 * randomness if /dev/random/urandom is out to lunch.
198 */
199 for (cp = buf, i = 0; i < nbytes; i++)
200 *cp++ ^= (rand() >> 7) & 0xFF;
201 #ifdef DO_JRAND_MIX
202 {
203 unsigned short tmp_seed[3];
204
205 memcpy(tmp_seed, jrand_seed, sizeof(tmp_seed));
206 jrand_seed[2] = jrand_seed[2] ^ syscall(__NR_gettid);
207 for (cp = buf, i = 0; i < nbytes; i++)
208 *cp++ ^= (jrand48(tmp_seed) >> 7) & 0xFF;
209 memcpy(jrand_seed, tmp_seed,
210 sizeof(jrand_seed) - sizeof(unsigned short));
211 }
212 #endif
213
214 return;
215 }
216
217 /*
218 * Get the ethernet hardware address, if we can find it...
219 *
220 * XXX for a windows version, probably should use GetAdaptersInfo:
221 * http://www.codeguru.com/cpp/i-n/network/networkinformation/article.php/c5451
222 * commenting out get_node_id just to get gen_uuid to compile under windows
223 * is not the right way to go!
224 */
get_node_id(unsigned char * node_id)225 static int get_node_id(unsigned char *node_id)
226 {
227 #ifdef HAVE_NET_IF_H
228 int sd;
229 struct ifreq ifr, *ifrp;
230 struct ifconf ifc;
231 char buf[1024];
232 int n, i;
233 unsigned char *a;
234 #ifdef HAVE_NET_IF_DL_H
235 struct sockaddr_dl *sdlp;
236 #endif
237
238 /*
239 * BSD 4.4 defines the size of an ifreq to be
240 * max(sizeof(ifreq), sizeof(ifreq.ifr_name)+ifreq.ifr_addr.sa_len
241 * However, under earlier systems, sa_len isn't present, so the size is
242 * just sizeof(struct ifreq)
243 */
244 #ifdef HAVE_SA_LEN
245 #ifndef max
246 #define max(a,b) ((a) > (b) ? (a) : (b))
247 #endif
248 #define ifreq_size(i) max(sizeof(struct ifreq),\
249 sizeof((i).ifr_name)+(i).ifr_addr.sa_len)
250 #else
251 #define ifreq_size(i) sizeof(struct ifreq)
252 #endif /* HAVE_SA_LEN*/
253
254 sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
255 if (sd < 0) {
256 return -1;
257 }
258 memset(buf, 0, sizeof(buf));
259 ifc.ifc_len = sizeof(buf);
260 ifc.ifc_buf = buf;
261 if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) {
262 close(sd);
263 return -1;
264 }
265 n = ifc.ifc_len;
266 for (i = 0; i < n; i+= ifreq_size(*ifrp) ) {
267 ifrp = (struct ifreq *)((char *) ifc.ifc_buf+i);
268 strncpy(ifr.ifr_name, ifrp->ifr_name, IFNAMSIZ);
269 #ifdef SIOCGIFHWADDR
270 if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)
271 continue;
272 a = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
273 #else
274 #ifdef SIOCGENADDR
275 if (ioctl(sd, SIOCGENADDR, &ifr) < 0)
276 continue;
277 a = (unsigned char *) ifr.ifr_enaddr;
278 #else
279 #ifdef HAVE_NET_IF_DL_H
280 sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr;
281 if ((sdlp->sdl_family != AF_LINK) || (sdlp->sdl_alen != 6))
282 continue;
283 a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen];
284 #else
285 /*
286 * XXX we don't have a way of getting the hardware
287 * address
288 */
289 close(sd);
290 return 0;
291 #endif /* HAVE_NET_IF_DL_H */
292 #endif /* SIOCGENADDR */
293 #endif /* SIOCGIFHWADDR */
294 if (!a[0] && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
295 continue;
296 if (node_id) {
297 memcpy(node_id, a, 6);
298 close(sd);
299 return 1;
300 }
301 }
302 close(sd);
303 #endif
304 return 0;
305 }
306
307 /* Assume that the gettimeofday() has microsecond granularity */
308 #define MAX_ADJUSTMENT 10
309
get_clock(uint32_t * clock_high,uint32_t * clock_low,uint16_t * ret_clock_seq,int * num)310 static int get_clock(uint32_t *clock_high, uint32_t *clock_low,
311 uint16_t *ret_clock_seq, int *num)
312 {
313 THREAD_LOCAL int adjustment = 0;
314 THREAD_LOCAL struct timeval last = {0, 0};
315 THREAD_LOCAL int state_fd = -2;
316 THREAD_LOCAL FILE *state_f;
317 THREAD_LOCAL uint16_t clock_seq;
318 struct timeval tv;
319 #ifndef _WIN32
320 struct flock fl;
321 #endif
322 uint64_t clock_reg;
323 mode_t save_umask;
324 int len;
325
326 if (state_fd == -2) {
327 save_umask = umask(0);
328 state_fd = open("/var/lib/libuuid/clock.txt",
329 O_RDWR|O_CREAT, 0660);
330 (void) umask(save_umask);
331 if (state_fd >= 0) {
332 state_f = fdopen(state_fd, "r+");
333 if (!state_f) {
334 close(state_fd);
335 state_fd = -1;
336 }
337 }
338 }
339 #ifndef _WIN32
340 fl.l_type = F_WRLCK;
341 fl.l_whence = SEEK_SET;
342 fl.l_start = 0;
343 fl.l_len = 0;
344 fl.l_pid = 0;
345 if (state_fd >= 0) {
346 rewind(state_f);
347 while (fcntl(state_fd, F_SETLKW, &fl) < 0) {
348 if ((errno == EAGAIN) || (errno == EINTR))
349 continue;
350 fclose(state_f);
351 state_fd = -1;
352 break;
353 }
354 }
355 #endif
356 if (state_fd >= 0) {
357 unsigned int cl;
358 unsigned long tv1, tv2;
359 int a;
360
361 if (fscanf(state_f, "clock: %04x tv: %lu %lu adj: %d\n",
362 &cl, &tv1, &tv2, &a) == 4) {
363 clock_seq = cl & 0x3FFF;
364 last.tv_sec = tv1;
365 last.tv_usec = tv2;
366 adjustment = a;
367 }
368 }
369
370 if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
371 get_random_bytes(&clock_seq, sizeof(clock_seq));
372 clock_seq &= 0x3FFF;
373 gettimeofday(&last, 0);
374 last.tv_sec--;
375 }
376
377 try_again:
378 gettimeofday(&tv, 0);
379 if ((tv.tv_sec < last.tv_sec) ||
380 ((tv.tv_sec == last.tv_sec) &&
381 (tv.tv_usec < last.tv_usec))) {
382 clock_seq = (clock_seq+1) & 0x3FFF;
383 adjustment = 0;
384 last = tv;
385 } else if ((tv.tv_sec == last.tv_sec) &&
386 (tv.tv_usec == last.tv_usec)) {
387 if (adjustment >= MAX_ADJUSTMENT)
388 goto try_again;
389 adjustment++;
390 } else {
391 adjustment = 0;
392 last = tv;
393 }
394
395 clock_reg = tv.tv_usec*10 + adjustment;
396 clock_reg += ((uint64_t) tv.tv_sec)*10000000;
397 clock_reg += (((uint64_t) 0x01B21DD2) << 32) + 0x13814000;
398
399 if (num && (*num > 1)) {
400 adjustment += *num - 1;
401 last.tv_usec += adjustment / 10;
402 adjustment = adjustment % 10;
403 last.tv_sec += last.tv_usec / 1000000;
404 last.tv_usec = last.tv_usec % 1000000;
405 }
406
407 if (state_fd > 0) {
408 rewind(state_f);
409 len = fprintf(state_f,
410 "clock: %04x tv: %016lu %08lu adj: %08d\n",
411 clock_seq, last.tv_sec, (long)last.tv_usec,
412 adjustment);
413 fflush(state_f);
414 if (ftruncate(state_fd, len) < 0) {
415 fprintf(state_f, " \n");
416 fflush(state_f);
417 }
418 rewind(state_f);
419 #ifndef _WIN32
420 fl.l_type = F_UNLCK;
421 if (fcntl(state_fd, F_SETLK, &fl) < 0) {
422 fclose(state_f);
423 state_fd = -1;
424 }
425 #endif
426 }
427
428 *clock_high = clock_reg >> 32;
429 *clock_low = clock_reg;
430 *ret_clock_seq = clock_seq;
431 return 0;
432 }
433
434 #if defined(USE_UUIDD) && defined(HAVE_SYS_UN_H)
read_all(int fd,char * buf,size_t count)435 static ssize_t read_all(int fd, char *buf, size_t count)
436 {
437 ssize_t ret;
438 ssize_t c = 0;
439 int tries = 0;
440
441 memset(buf, 0, count);
442 while (count > 0) {
443 ret = read(fd, buf, count);
444 if (ret <= 0) {
445 if ((errno == EAGAIN || errno == EINTR || ret == 0) &&
446 (tries++ < 5))
447 continue;
448 return c ? c : -1;
449 }
450 if (ret > 0)
451 tries = 0;
452 count -= ret;
453 buf += ret;
454 c += ret;
455 }
456 return c;
457 }
458
459 /*
460 * Close all file descriptors
461 */
close_all_fds(void)462 static void close_all_fds(void)
463 {
464 int i, max;
465
466 #if defined(HAVE_SYSCONF) && defined(_SC_OPEN_MAX)
467 max = sysconf(_SC_OPEN_MAX);
468 #elif defined(HAVE_GETDTABLESIZE)
469 max = getdtablesize();
470 #elif defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
471 struct rlimit rl;
472
473 getrlimit(RLIMIT_NOFILE, &rl);
474 max = rl.rlim_cur;
475 #else
476 max = OPEN_MAX;
477 #endif
478
479 for (i=0; i < max; i++) {
480 close(i);
481 if (i <= 2)
482 open("/dev/null", O_RDWR);
483 }
484 }
485 #endif /* defined(USE_UUIDD) && defined(HAVE_SYS_UN_H) */
486
487 #if __GNUC_PREREQ (4, 6)
488 #pragma GCC diagnostic push
489 #if !defined(USE_UUIDD) || !defined(HAVE_SYS_UN_H)
490 #pragma GCC diagnostic ignored "-Wunused-parameter"
491 #endif
492 #endif
493 /*
494 * Try using the uuidd daemon to generate the UUID
495 *
496 * Returns 0 on success, non-zero on failure.
497 */
get_uuid_via_daemon(int op,uuid_t out,int * num)498 static int get_uuid_via_daemon(int op, uuid_t out, int *num)
499 {
500 #if defined(USE_UUIDD) && defined(HAVE_SYS_UN_H)
501 char op_buf[64];
502 int op_len;
503 int s;
504 ssize_t ret;
505 int32_t reply_len = 0, expected = 16;
506 struct sockaddr_un srv_addr;
507 struct stat st;
508 pid_t pid;
509 static const char *uuidd_path = UUIDD_PATH;
510 static int access_ret = -2;
511 static int start_attempts = 0;
512
513 if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
514 return -1;
515
516 srv_addr.sun_family = AF_UNIX;
517 strcpy(srv_addr.sun_path, UUIDD_SOCKET_PATH);
518
519 if (connect(s, (const struct sockaddr *) &srv_addr,
520 sizeof(struct sockaddr_un)) < 0) {
521 if (access_ret == -2)
522 access_ret = access(uuidd_path, X_OK);
523 if (access_ret == 0)
524 access_ret = stat(uuidd_path, &st);
525 if (access_ret == 0 && (st.st_mode & (S_ISUID | S_ISGID)) == 0)
526 access_ret = access(UUIDD_DIR, W_OK);
527 if (access_ret == 0 && start_attempts++ < 5) {
528 if ((pid = fork()) == 0) {
529 close_all_fds();
530 execl(uuidd_path, "uuidd", "-qT", "300",
531 (char *) NULL);
532 exit(1);
533 }
534 (void) waitpid(pid, 0, 0);
535 if (connect(s, (const struct sockaddr *) &srv_addr,
536 sizeof(struct sockaddr_un)) < 0)
537 goto fail;
538 } else
539 goto fail;
540 }
541 op_buf[0] = op;
542 op_len = 1;
543 if (op == UUIDD_OP_BULK_TIME_UUID) {
544 memcpy(op_buf+1, num, sizeof(*num));
545 op_len += sizeof(*num);
546 expected += sizeof(*num);
547 }
548
549 ret = write(s, op_buf, op_len);
550 if (ret < 1)
551 goto fail;
552
553 ret = read_all(s, (char *) &reply_len, sizeof(reply_len));
554 if (ret < 0)
555 goto fail;
556
557 if (reply_len != expected)
558 goto fail;
559
560 ret = read_all(s, op_buf, reply_len);
561
562 if (op == UUIDD_OP_BULK_TIME_UUID)
563 memcpy(op_buf+16, num, sizeof(int));
564
565 memcpy(out, op_buf, 16);
566
567 close(s);
568 return ((ret == expected) ? 0 : -1);
569
570 fail:
571 close(s);
572 #endif
573 return -1;
574 }
575 #if __GNUC_PREREQ (4, 6)
576 #pragma GCC diagnostic pop
577 #endif
578
uuid__generate_time(uuid_t out,int * num)579 void uuid__generate_time(uuid_t out, int *num)
580 {
581 static unsigned char node_id[6];
582 static int has_init = 0;
583 struct uuid uu;
584 uint32_t clock_mid;
585
586 if (!has_init) {
587 if (get_node_id(node_id) <= 0) {
588 get_random_bytes(node_id, 6);
589 /*
590 * Set multicast bit, to prevent conflicts
591 * with IEEE 802 addresses obtained from
592 * network cards
593 */
594 node_id[0] |= 0x01;
595 }
596 has_init = 1;
597 }
598 get_clock(&clock_mid, &uu.time_low, &uu.clock_seq, num);
599 uu.clock_seq |= 0x8000;
600 uu.time_mid = (uint16_t) clock_mid;
601 uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) | 0x1000;
602 memcpy(uu.node, node_id, 6);
603 uuid_pack(&uu, out);
604 }
605
uuid_generate_time(uuid_t out)606 void uuid_generate_time(uuid_t out)
607 {
608 #ifdef TLS
609 THREAD_LOCAL int num = 0;
610 THREAD_LOCAL struct uuid uu;
611 THREAD_LOCAL time_t last_time = 0;
612 time_t now;
613
614 if (num > 0) {
615 now = time(0);
616 if (now > last_time+1)
617 num = 0;
618 }
619 if (num <= 0) {
620 num = 1000;
621 if (get_uuid_via_daemon(UUIDD_OP_BULK_TIME_UUID,
622 out, &num) == 0) {
623 last_time = time(0);
624 uuid_unpack(out, &uu);
625 num--;
626 return;
627 }
628 num = 0;
629 }
630 if (num > 0) {
631 uu.time_low++;
632 if (uu.time_low == 0) {
633 uu.time_mid++;
634 if (uu.time_mid == 0)
635 uu.time_hi_and_version++;
636 }
637 num--;
638 uuid_pack(&uu, out);
639 return;
640 }
641 #else
642 if (get_uuid_via_daemon(UUIDD_OP_TIME_UUID, out, 0) == 0)
643 return;
644 #endif
645
646 uuid__generate_time(out, 0);
647 }
648
649
uuid__generate_random(uuid_t out,int * num)650 void uuid__generate_random(uuid_t out, int *num)
651 {
652 uuid_t buf;
653 struct uuid uu;
654 int i, n;
655
656 if (!num || !*num)
657 n = 1;
658 else
659 n = *num;
660
661 for (i = 0; i < n; i++) {
662 get_random_bytes(buf, sizeof(buf));
663 uuid_unpack(buf, &uu);
664
665 uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
666 uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF)
667 | 0x4000;
668 uuid_pack(&uu, out);
669 out += sizeof(uuid_t);
670 }
671 }
672
uuid_generate_random(uuid_t out)673 void uuid_generate_random(uuid_t out)
674 {
675 int num = 1;
676 /* No real reason to use the daemon for random uuid's -- yet */
677
678 uuid__generate_random(out, &num);
679 }
680
681
682 /*
683 * This is the generic front-end to uuid_generate_random and
684 * uuid_generate_time. It uses uuid_generate_random only if
685 * /dev/urandom is available, since otherwise we won't have
686 * high-quality randomness.
687 */
uuid_generate(uuid_t out)688 void uuid_generate(uuid_t out)
689 {
690 if (get_random_fd() >= 0)
691 uuid_generate_random(out);
692 else
693 uuid_generate_time(out);
694 }
695