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_RANDOM_H
74 #include <sys/random.h>
75 #endif
76 #ifdef HAVE_SYS_SOCKET_H
77 #include <sys/socket.h>
78 #endif
79 #ifdef HAVE_SYS_UN_H
80 #include <sys/un.h>
81 #endif
82 #ifdef HAVE_SYS_SOCKIO_H
83 #include <sys/sockio.h>
84 #endif
85 #ifdef HAVE_NET_IF_H
86 #include <net/if.h>
87 #endif
88 #ifdef HAVE_NETINET_IN_H
89 #include <netinet/in.h>
90 #endif
91 #ifdef HAVE_NET_IF_DL_H
92 #include <net/if_dl.h>
93 #endif
94 #if defined(__linux__) && defined(HAVE_SYS_SYSCALL_H)
95 #include <sys/syscall.h>
96 #endif
97 #ifdef HAVE_SYS_RESOURCE_H
98 #include <sys/resource.h>
99 #endif
100 #include <ifaddrs.h>
101
102 #include "uuidP.h"
103 #include "uuidd.h"
104
105 #ifdef HAVE_SRANDOM
106 #define srand(x) srandom(x)
107 #define rand() random()
108 #endif
109
110 #ifdef TLS
111 #define THREAD_LOCAL static TLS
112 #else
113 #define THREAD_LOCAL static
114 #endif
115
116 #if defined(__linux__) && defined(__NR_gettid) && defined(HAVE_JRAND48)
117 #define DO_JRAND_MIX
118 THREAD_LOCAL unsigned short jrand_seed[3];
119 #endif
120
121 #ifdef _WIN32
122 #ifndef USE_MINGW
gettimeofday(struct timeval * tv,void * dummy)123 static void gettimeofday (struct timeval *tv, void *dummy)
124 {
125 FILETIME ftime;
126 uint64_t n;
127
128 GetSystemTimeAsFileTime (&ftime);
129 n = (((uint64_t) ftime.dwHighDateTime << 32)
130 + (uint64_t) ftime.dwLowDateTime);
131 if (n) {
132 n /= 10;
133 n -= ((369 * 365 + 89) * (uint64_t) 86400) * 1000000;
134 }
135
136 tv->tv_sec = n / 1000000;
137 tv->tv_usec = n % 1000000;
138 }
139 #endif
140 #endif
141
get_random_fd(void)142 static int get_random_fd(void)
143 {
144 struct timeval tv;
145 static int fd = -2;
146 int i;
147
148 if (fd == -2) {
149 gettimeofday(&tv, 0);
150 #ifndef _WIN32
151 fd = open("/dev/urandom", O_RDONLY);
152 if (fd == -1)
153 fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
154 if (fd >= 0) {
155 i = fcntl(fd, F_GETFD);
156 if (i >= 0)
157 fcntl(fd, F_SETFD, i | FD_CLOEXEC);
158 }
159 #endif
160 srand(((unsigned)getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
161 #ifdef DO_JRAND_MIX
162 jrand_seed[0] = getpid() ^ (tv.tv_sec & 0xFFFF);
163 jrand_seed[1] = getppid() ^ (tv.tv_usec & 0xFFFF);
164 jrand_seed[2] = (tv.tv_sec ^ tv.tv_usec) >> 16;
165 #endif
166 }
167 /* Crank the random number generator a few times */
168 gettimeofday(&tv, 0);
169 for (i = (tv.tv_sec ^ tv.tv_usec) & 0x1F; i > 0; i--)
170 rand();
171 return fd;
172 }
173
174
175 /*
176 * Generate a series of random bytes. Use /dev/urandom if possible,
177 * and if not, use srandom/random.
178 */
get_random_bytes(void * buf,int nbytes)179 static void get_random_bytes(void *buf, int nbytes)
180 {
181 int i, n = nbytes, fd;
182 int lose_counter = 0;
183 unsigned char *cp = buf;
184
185 #ifdef HAVE_GETRANDOM
186 i = getrandom(buf, nbytes, 0);
187 if (i == nbytes)
188 return;
189 #endif
190 #ifdef HAVE_GETENTROPY
191 if (getentropy(buf, nbytes) == 0)
192 return;
193 #endif
194
195 fd = get_random_fd();
196 if (fd >= 0) {
197 while (n > 0) {
198 i = read(fd, cp, n);
199 if (i <= 0) {
200 if (lose_counter++ > 16)
201 break;
202 continue;
203 }
204 n -= i;
205 cp += i;
206 lose_counter = 0;
207 }
208 }
209
210 /*
211 * We do this all the time, but this is the only source of
212 * randomness if /dev/random/urandom is out to lunch.
213 */
214 for (cp = buf, i = 0; i < nbytes; i++)
215 *cp++ ^= (rand() >> 7) & 0xFF;
216 #ifdef DO_JRAND_MIX
217 {
218 unsigned short tmp_seed[3];
219
220 memcpy(tmp_seed, jrand_seed, sizeof(tmp_seed));
221 jrand_seed[2] = jrand_seed[2] ^ syscall(__NR_gettid);
222 for (cp = buf, i = 0; i < nbytes; i++)
223 *cp++ ^= (jrand48(tmp_seed) >> 7) & 0xFF;
224 memcpy(jrand_seed, tmp_seed,
225 sizeof(jrand_seed) - sizeof(unsigned short));
226 }
227 #endif
228
229 return;
230 }
231
232 /*
233 * Get the ethernet hardware address, if we can find it...
234 *
235 * XXX for a windows version, probably should use GetAdaptersInfo:
236 * http://www.codeguru.com/cpp/i-n/network/networkinformation/article.php/c5451
237 * commenting out get_node_id just to get gen_uuid to compile under windows
238 * is not the right way to go!
239 */
get_node_id(unsigned char * node_id)240 static int get_node_id(unsigned char *node_id)
241 {
242 #ifdef HAVE_NET_IF_H
243 int sd;
244 struct ifreq ifr, *ifrp;
245 struct ifconf ifc;
246 char buf[1024];
247 int n, i;
248 unsigned char *a;
249 #ifdef HAVE_NET_IF_DL_H
250 struct sockaddr_dl *sdlp;
251 #endif
252
253 /*
254 * BSD 4.4 defines the size of an ifreq to be
255 * max(sizeof(ifreq), sizeof(ifreq.ifr_name)+ifreq.ifr_addr.sa_len
256 * However, under earlier systems, sa_len isn't present, so the size is
257 * just sizeof(struct ifreq)
258 */
259 #ifdef HAVE_SA_LEN
260 #ifndef max
261 #define max(a,b) ((a) > (b) ? (a) : (b))
262 #endif
263 #define ifreq_size(i) max(sizeof(struct ifreq),\
264 sizeof((i).ifr_name)+(i).ifr_addr.sa_len)
265 #else
266 #define ifreq_size(i) sizeof(struct ifreq)
267 #endif /* HAVE_SA_LEN*/
268
269 sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
270 if (sd < 0) {
271 return -1;
272 }
273 memset(buf, 0, sizeof(buf));
274 ifc.ifc_len = sizeof(buf);
275 ifc.ifc_buf = buf;
276 if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) {
277 close(sd);
278 return -1;
279 }
280 n = ifc.ifc_len;
281 for (i = 0; i < n; i+= ifreq_size(*ifrp) ) {
282 ifrp = (struct ifreq *)((char *) ifc.ifc_buf+i);
283 strncpy(ifr.ifr_name, ifrp->ifr_name, IFNAMSIZ);
284 #ifdef SIOCGIFHWADDR
285 if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)
286 continue;
287 a = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
288 #else
289 #ifdef SIOCGENADDR
290 if (ioctl(sd, SIOCGENADDR, &ifr) < 0)
291 continue;
292 a = (unsigned char *) ifr.ifr_enaddr;
293 #else
294 #ifdef HAVE_NET_IF_DL_H
295 sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr;
296 if ((sdlp->sdl_family != AF_LINK) || (sdlp->sdl_alen != 6))
297 continue;
298 a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen];
299 #else
300 /*
301 * XXX we don't have a way of getting the hardware
302 * address
303 */
304 close(sd);
305 return 0;
306 #endif /* HAVE_NET_IF_DL_H */
307 #endif /* SIOCGENADDR */
308 #endif /* SIOCGIFHWADDR */
309 if (!a[0] && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
310 continue;
311 if (node_id) {
312 memcpy(node_id, a, 6);
313 close(sd);
314 return 1;
315 }
316 }
317 close(sd);
318 #else
319 struct ifaddrs *ifaddrsp, *ifaddrp;
320 unsigned char *a;
321
322 if (getifaddrs(&ifaddrsp) < 0)
323 return -1;
324 for (ifaddrp = ifaddrsp; ifaddrp != NULL; ifaddrp = ifaddrp->ifa_next)
325 {
326 if (ifaddrp->ifa_addr == NULL)
327 continue;
328 if (ifaddrp->ifa_addr->sa_family != AF_LINK)
329 continue;
330 a = LLADDR((struct sockaddr_dl *)ifaddrp->ifa_addr);
331 if (!a[0] && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
332 continue;
333 if (node_id) {
334 memcpy(node_id, a, 6);
335 freeifaddrs(ifaddrsp);
336 return 1;
337 }
338 }
339 freeifaddrs(ifaddrsp);
340 #endif
341 return 0;
342 }
343
344 /* Assume that the gettimeofday() has microsecond granularity */
345 #define MAX_ADJUSTMENT 10
346
get_clock(uint32_t * clock_high,uint32_t * clock_low,uint16_t * ret_clock_seq,int * num)347 static int get_clock(uint32_t *clock_high, uint32_t *clock_low,
348 uint16_t *ret_clock_seq, int *num)
349 {
350 THREAD_LOCAL int adjustment = 0;
351 THREAD_LOCAL struct timeval last = {0, 0};
352 THREAD_LOCAL int state_fd = -2;
353 THREAD_LOCAL FILE *state_f;
354 THREAD_LOCAL uint16_t clock_seq;
355 struct timeval tv;
356 #ifndef _WIN32
357 struct flock fl;
358 #endif
359 uint64_t clock_reg;
360 mode_t save_umask;
361 int len;
362
363 if (state_fd == -2) {
364 save_umask = umask(0);
365 state_fd = open("/var/run/libuuid/clock.txt",
366 O_RDWR|O_CREAT, 0660);
367 (void) umask(save_umask);
368 if (state_fd >= 0) {
369 state_f = fdopen(state_fd, "r+");
370 if (!state_f) {
371 close(state_fd);
372 state_fd = -1;
373 }
374 }
375 }
376 #ifndef _WIN32
377 fl.l_type = F_WRLCK;
378 fl.l_whence = SEEK_SET;
379 fl.l_start = 0;
380 fl.l_len = 0;
381 fl.l_pid = 0;
382 if (state_fd >= 0) {
383 rewind(state_f);
384 while (fcntl(state_fd, F_SETLKW, &fl) < 0) {
385 if ((errno == EAGAIN) || (errno == EINTR))
386 continue;
387 fclose(state_f);
388 state_fd = -1;
389 break;
390 }
391 }
392 #endif
393 if (state_fd >= 0) {
394 unsigned int cl;
395 unsigned long tv1, tv2;
396 int a;
397
398 if (fscanf(state_f, "clock: %04x tv: %lu %lu adj: %d\n",
399 &cl, &tv1, &tv2, &a) == 4) {
400 clock_seq = cl & 0x3FFF;
401 last.tv_sec = tv1;
402 last.tv_usec = tv2;
403 adjustment = a;
404 }
405 }
406
407 if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
408 get_random_bytes(&clock_seq, sizeof(clock_seq));
409 clock_seq &= 0x3FFF;
410 gettimeofday(&last, 0);
411 last.tv_sec--;
412 }
413
414 try_again:
415 gettimeofday(&tv, 0);
416 if ((tv.tv_sec < last.tv_sec) ||
417 ((tv.tv_sec == last.tv_sec) &&
418 (tv.tv_usec < last.tv_usec))) {
419 clock_seq = (clock_seq+1) & 0x3FFF;
420 adjustment = 0;
421 last = tv;
422 } else if ((tv.tv_sec == last.tv_sec) &&
423 (tv.tv_usec == last.tv_usec)) {
424 if (adjustment >= MAX_ADJUSTMENT)
425 goto try_again;
426 adjustment++;
427 } else {
428 adjustment = 0;
429 last = tv;
430 }
431
432 clock_reg = tv.tv_usec*10 + adjustment;
433 clock_reg += ((uint64_t) tv.tv_sec)*10000000;
434 clock_reg += (((uint64_t) 0x01B21DD2) << 32) + 0x13814000;
435
436 if (num && (*num > 1)) {
437 adjustment += *num - 1;
438 last.tv_usec += adjustment / 10;
439 adjustment = adjustment % 10;
440 last.tv_sec += last.tv_usec / 1000000;
441 last.tv_usec = last.tv_usec % 1000000;
442 }
443
444 if (state_fd > 0) {
445 rewind(state_f);
446 len = fprintf(state_f,
447 "clock: %04x tv: %016lu %08lu adj: %08d\n",
448 clock_seq, (unsigned long)last.tv_sec,
449 (unsigned long)last.tv_usec, adjustment);
450 fflush(state_f);
451 if (ftruncate(state_fd, len) < 0) {
452 fprintf(state_f, " \n");
453 fflush(state_f);
454 }
455 rewind(state_f);
456 #ifndef _WIN32
457 fl.l_type = F_UNLCK;
458 if (fcntl(state_fd, F_SETLK, &fl) < 0) {
459 fclose(state_f);
460 state_fd = -1;
461 }
462 #endif
463 }
464
465 *clock_high = clock_reg >> 32;
466 *clock_low = clock_reg;
467 *ret_clock_seq = clock_seq;
468 return 0;
469 }
470
471 #if defined(USE_UUIDD) && defined(HAVE_SYS_UN_H)
read_all(int fd,char * buf,size_t count)472 static ssize_t read_all(int fd, char *buf, size_t count)
473 {
474 ssize_t ret;
475 ssize_t c = 0;
476 int tries = 0;
477
478 memset(buf, 0, count);
479 while (count > 0) {
480 ret = read(fd, buf, count);
481 if (ret <= 0) {
482 if ((errno == EAGAIN || errno == EINTR || ret == 0) &&
483 (tries++ < 5))
484 continue;
485 return c ? c : -1;
486 }
487 if (ret > 0)
488 tries = 0;
489 count -= ret;
490 buf += ret;
491 c += ret;
492 }
493 return c;
494 }
495
496 /*
497 * Close all file descriptors
498 */
close_all_fds(void)499 static void close_all_fds(void)
500 {
501 int i, max;
502
503 #if defined(HAVE_SYSCONF) && defined(_SC_OPEN_MAX)
504 max = sysconf(_SC_OPEN_MAX);
505 #elif defined(HAVE_GETDTABLESIZE)
506 max = getdtablesize();
507 #elif defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
508 struct rlimit rl;
509
510 getrlimit(RLIMIT_NOFILE, &rl);
511 max = rl.rlim_cur;
512 #else
513 max = OPEN_MAX;
514 #endif
515
516 for (i=0; i < max; i++) {
517 close(i);
518 if (i <= 2)
519 open("/dev/null", O_RDWR);
520 }
521 }
522 #endif /* defined(USE_UUIDD) && defined(HAVE_SYS_UN_H) */
523
524 #if __GNUC_PREREQ__ (4, 6)
525 #pragma GCC diagnostic push
526 #if !defined(USE_UUIDD) || !defined(HAVE_SYS_UN_H)
527 #pragma GCC diagnostic ignored "-Wunused-parameter"
528 #endif
529 #endif
530 /*
531 * Try using the uuidd daemon to generate the UUID
532 *
533 * Returns 0 on success, non-zero on failure.
534 */
get_uuid_via_daemon(int op,uuid_t out,int * num)535 static int get_uuid_via_daemon(int op, uuid_t out, int *num)
536 {
537 #if defined(USE_UUIDD) && defined(HAVE_SYS_UN_H)
538 char op_buf[64];
539 int op_len;
540 int s;
541 ssize_t ret;
542 int32_t reply_len = 0, expected = 16;
543 struct sockaddr_un srv_addr;
544 struct stat st;
545 pid_t pid;
546 static const char *uuidd_path = UUIDD_PATH;
547 static int access_ret = -2;
548 static int start_attempts = 0;
549
550 if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
551 return -1;
552
553 srv_addr.sun_family = AF_UNIX;
554 strcpy(srv_addr.sun_path, UUIDD_SOCKET_PATH);
555
556 if (connect(s, (const struct sockaddr *) &srv_addr,
557 sizeof(struct sockaddr_un)) < 0) {
558 if (access_ret == -2)
559 access_ret = access(uuidd_path, X_OK);
560 if (access_ret == 0)
561 access_ret = stat(uuidd_path, &st);
562 if (access_ret == 0 && (st.st_mode & (S_ISUID | S_ISGID)) == 0)
563 access_ret = access(UUIDD_DIR, W_OK);
564 if (access_ret == 0 && start_attempts++ < 5) {
565 if ((pid = fork()) == 0) {
566 close_all_fds();
567 execl(uuidd_path, "uuidd", "-qT", "300",
568 (char *) NULL);
569 exit(1);
570 }
571 (void) waitpid(pid, 0, 0);
572 if (connect(s, (const struct sockaddr *) &srv_addr,
573 sizeof(struct sockaddr_un)) < 0)
574 goto fail;
575 } else
576 goto fail;
577 }
578 op_buf[0] = op;
579 op_len = 1;
580 if (op == UUIDD_OP_BULK_TIME_UUID) {
581 memcpy(op_buf+1, num, sizeof(*num));
582 op_len += sizeof(*num);
583 expected += sizeof(*num);
584 }
585
586 ret = write(s, op_buf, op_len);
587 if (ret < 1)
588 goto fail;
589
590 ret = read_all(s, (char *) &reply_len, sizeof(reply_len));
591 if (ret < 0)
592 goto fail;
593
594 if (reply_len != expected)
595 goto fail;
596
597 ret = read_all(s, op_buf, reply_len);
598
599 if (op == UUIDD_OP_BULK_TIME_UUID)
600 memcpy(op_buf+16, num, sizeof(int));
601
602 memcpy(out, op_buf, 16);
603
604 close(s);
605 return ((ret == expected) ? 0 : -1);
606
607 fail:
608 close(s);
609 #endif
610 return -1;
611 }
612 #if __GNUC_PREREQ__ (4, 6)
613 #pragma GCC diagnostic pop
614 #endif
615
uuid__generate_time(uuid_t out,int * num)616 void uuid__generate_time(uuid_t out, int *num)
617 {
618 static unsigned char node_id[6];
619 static int has_init = 0;
620 struct uuid uu;
621 uint32_t clock_mid;
622
623 if (!has_init) {
624 if (get_node_id(node_id) <= 0) {
625 get_random_bytes(node_id, 6);
626 /*
627 * Set multicast bit, to prevent conflicts
628 * with IEEE 802 addresses obtained from
629 * network cards
630 */
631 node_id[0] |= 0x01;
632 }
633 has_init = 1;
634 }
635 get_clock(&clock_mid, &uu.time_low, &uu.clock_seq, num);
636 uu.clock_seq |= 0x8000;
637 uu.time_mid = (uint16_t) clock_mid;
638 uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) | 0x1000;
639 memcpy(uu.node, node_id, 6);
640 uuid_pack(&uu, out);
641 }
642
uuid_generate_time(uuid_t out)643 void uuid_generate_time(uuid_t out)
644 {
645 #ifdef TLS
646 THREAD_LOCAL int num = 0;
647 THREAD_LOCAL struct uuid uu;
648 THREAD_LOCAL time_t last_time = 0;
649 time_t now;
650
651 if (num > 0) {
652 now = time(0);
653 if (now > last_time+1)
654 num = 0;
655 }
656 if (num <= 0) {
657 num = 1000;
658 if (get_uuid_via_daemon(UUIDD_OP_BULK_TIME_UUID,
659 out, &num) == 0) {
660 last_time = time(0);
661 uuid_unpack(out, &uu);
662 num--;
663 return;
664 }
665 num = 0;
666 }
667 if (num > 0) {
668 uu.time_low++;
669 if (uu.time_low == 0) {
670 uu.time_mid++;
671 if (uu.time_mid == 0)
672 uu.time_hi_and_version++;
673 }
674 num--;
675 uuid_pack(&uu, out);
676 return;
677 }
678 #else
679 if (get_uuid_via_daemon(UUIDD_OP_TIME_UUID, out, 0) == 0)
680 return;
681 #endif
682
683 uuid__generate_time(out, 0);
684 }
685
686
uuid__generate_random(uuid_t out,int * num)687 void uuid__generate_random(uuid_t out, int *num)
688 {
689 uuid_t buf;
690 struct uuid uu;
691 int i, n;
692
693 if (!num || !*num)
694 n = 1;
695 else
696 n = *num;
697
698 for (i = 0; i < n; i++) {
699 get_random_bytes(buf, sizeof(buf));
700 uuid_unpack(buf, &uu);
701
702 uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
703 uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF)
704 | 0x4000;
705 uuid_pack(&uu, out);
706 out += sizeof(uuid_t);
707 }
708 }
709
uuid_generate_random(uuid_t out)710 void uuid_generate_random(uuid_t out)
711 {
712 int num = 1;
713 /* No real reason to use the daemon for random uuid's -- yet */
714
715 uuid__generate_random(out, &num);
716 }
717
718
719 /*
720 * This is the generic front-end to uuid_generate_random and
721 * uuid_generate_time. It uses uuid_generate_random only if
722 * /dev/urandom is available, since otherwise we won't have
723 * high-quality randomness.
724 */
uuid_generate(uuid_t out)725 void uuid_generate(uuid_t out)
726 {
727 if (get_random_fd() >= 0)
728 uuid_generate_random(out);
729 else
730 uuid_generate_time(out);
731 }
732