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