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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((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 #pragma GCC diagnostic push
488 #if !defined(USE_UUIDD) || !defined(HAVE_SYS_UN_H)
489 #pragma GCC diagnostic ignored "-Wunused-parameter"
490 #endif
491 /*
492  * Try using the uuidd daemon to generate the UUID
493  *
494  * Returns 0 on success, non-zero on failure.
495  */
get_uuid_via_daemon(int op,uuid_t out,int * num)496 static int get_uuid_via_daemon(int op, uuid_t out, int *num)
497 {
498 #if defined(USE_UUIDD) && defined(HAVE_SYS_UN_H)
499 	char op_buf[64];
500 	int op_len;
501 	int s;
502 	ssize_t ret;
503 	int32_t reply_len = 0, expected = 16;
504 	struct sockaddr_un srv_addr;
505 	struct stat st;
506 	pid_t pid;
507 	static const char *uuidd_path = UUIDD_PATH;
508 	static int access_ret = -2;
509 	static int start_attempts = 0;
510 
511 	if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
512 		return -1;
513 
514 	srv_addr.sun_family = AF_UNIX;
515 	strcpy(srv_addr.sun_path, UUIDD_SOCKET_PATH);
516 
517 	if (connect(s, (const struct sockaddr *) &srv_addr,
518 		    sizeof(struct sockaddr_un)) < 0) {
519 		if (access_ret == -2)
520 			access_ret = access(uuidd_path, X_OK);
521 		if (access_ret == 0)
522 			access_ret = stat(uuidd_path, &st);
523 		if (access_ret == 0 && (st.st_mode & (S_ISUID | S_ISGID)) == 0)
524 			access_ret = access(UUIDD_DIR, W_OK);
525 		if (access_ret == 0 && start_attempts++ < 5) {
526 			if ((pid = fork()) == 0) {
527 				close_all_fds();
528 				execl(uuidd_path, "uuidd", "-qT", "300",
529 				      (char *) NULL);
530 				exit(1);
531 			}
532 			(void) waitpid(pid, 0, 0);
533 			if (connect(s, (const struct sockaddr *) &srv_addr,
534 				    sizeof(struct sockaddr_un)) < 0)
535 				goto fail;
536 		} else
537 			goto fail;
538 	}
539 	op_buf[0] = op;
540 	op_len = 1;
541 	if (op == UUIDD_OP_BULK_TIME_UUID) {
542 		memcpy(op_buf+1, num, sizeof(*num));
543 		op_len += sizeof(*num);
544 		expected += sizeof(*num);
545 	}
546 
547 	ret = write(s, op_buf, op_len);
548 	if (ret < 1)
549 		goto fail;
550 
551 	ret = read_all(s, (char *) &reply_len, sizeof(reply_len));
552 	if (ret < 0)
553 		goto fail;
554 
555 	if (reply_len != expected)
556 		goto fail;
557 
558 	ret = read_all(s, op_buf, reply_len);
559 
560 	if (op == UUIDD_OP_BULK_TIME_UUID)
561 		memcpy(op_buf+16, num, sizeof(int));
562 
563 	memcpy(out, op_buf, 16);
564 
565 	close(s);
566 	return ((ret == expected) ? 0 : -1);
567 
568 fail:
569 	close(s);
570 #endif
571 	return -1;
572 }
573 #pragma GCC diagnostic pop
574 
uuid__generate_time(uuid_t out,int * num)575 void uuid__generate_time(uuid_t out, int *num)
576 {
577 	static unsigned char node_id[6];
578 	static int has_init = 0;
579 	struct uuid uu;
580 	uint32_t	clock_mid;
581 
582 	if (!has_init) {
583 		if (get_node_id(node_id) <= 0) {
584 			get_random_bytes(node_id, 6);
585 			/*
586 			 * Set multicast bit, to prevent conflicts
587 			 * with IEEE 802 addresses obtained from
588 			 * network cards
589 			 */
590 			node_id[0] |= 0x01;
591 		}
592 		has_init = 1;
593 	}
594 	get_clock(&clock_mid, &uu.time_low, &uu.clock_seq, num);
595 	uu.clock_seq |= 0x8000;
596 	uu.time_mid = (uint16_t) clock_mid;
597 	uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) | 0x1000;
598 	memcpy(uu.node, node_id, 6);
599 	uuid_pack(&uu, out);
600 }
601 
uuid_generate_time(uuid_t out)602 void uuid_generate_time(uuid_t out)
603 {
604 #ifdef TLS
605 	THREAD_LOCAL int		num = 0;
606 	THREAD_LOCAL struct uuid	uu;
607 	THREAD_LOCAL time_t		last_time = 0;
608 	time_t				now;
609 
610 	if (num > 0) {
611 		now = time(0);
612 		if (now > last_time+1)
613 			num = 0;
614 	}
615 	if (num <= 0) {
616 		num = 1000;
617 		if (get_uuid_via_daemon(UUIDD_OP_BULK_TIME_UUID,
618 					out, &num) == 0) {
619 			last_time = time(0);
620 			uuid_unpack(out, &uu);
621 			num--;
622 			return;
623 		}
624 		num = 0;
625 	}
626 	if (num > 0) {
627 		uu.time_low++;
628 		if (uu.time_low == 0) {
629 			uu.time_mid++;
630 			if (uu.time_mid == 0)
631 				uu.time_hi_and_version++;
632 		}
633 		num--;
634 		uuid_pack(&uu, out);
635 		return;
636 	}
637 #else
638 	if (get_uuid_via_daemon(UUIDD_OP_TIME_UUID, out, 0) == 0)
639 		return;
640 #endif
641 
642 	uuid__generate_time(out, 0);
643 }
644 
645 
uuid__generate_random(uuid_t out,int * num)646 void uuid__generate_random(uuid_t out, int *num)
647 {
648 	uuid_t	buf;
649 	struct uuid uu;
650 	int i, n;
651 
652 	if (!num || !*num)
653 		n = 1;
654 	else
655 		n = *num;
656 
657 	for (i = 0; i < n; i++) {
658 		get_random_bytes(buf, sizeof(buf));
659 		uuid_unpack(buf, &uu);
660 
661 		uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
662 		uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF)
663 			| 0x4000;
664 		uuid_pack(&uu, out);
665 		out += sizeof(uuid_t);
666 	}
667 }
668 
uuid_generate_random(uuid_t out)669 void uuid_generate_random(uuid_t out)
670 {
671 	int	num = 1;
672 	/* No real reason to use the daemon for random uuid's -- yet */
673 
674 	uuid__generate_random(out, &num);
675 }
676 
677 
678 /*
679  * This is the generic front-end to uuid_generate_random and
680  * uuid_generate_time.  It uses uuid_generate_random only if
681  * /dev/urandom is available, since otherwise we won't have
682  * high-quality randomness.
683  */
uuid_generate(uuid_t out)684 void uuid_generate(uuid_t out)
685 {
686 	if (get_random_fd() >= 0)
687 		uuid_generate_random(out);
688 	else
689 		uuid_generate_time(out);
690 }
691