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
70THREAD_LOCAL unsigned short jrand_seed[3];
71#endif
72
73static 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 */
108static 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 */
159static 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
227static 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
290try_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
345void 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
372void 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
415void 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
438void 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 */
450static 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 */
465void 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
473void uuid_generate(uuid_t out)
474{
475	uuid_generate_random(out);
476}
477#endif
478