lib/uuid/gen_uuid.c - platform/external/e2fsprogs - Git at Google

 /*
  * gen_uuid.c --- generate a DCE-compatible uuid
  *
  * Copyright (C) 1996, 1997, 1998, 1999 Theodore Ts'o.
  *
  * %Begin-Header%
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, and the entire permission notice in its entirety,
  *    including the disclaimer of warranties.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. The name of the author may not be used to endorse or promote
  *    products derived from this software without specific prior
  *    written permission.
  *
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
  * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
  * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  * %End-Header%
  */

 /*
  * Force inclusion of SVID stuff since we need it if we're compiling in
  * gcc-wall wall mode
  */
 #define _SVID_SOURCE

 #include <stdio.h>
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif
 #ifdef HAVE_STDLIB_H
 #include <stdlib.h>
 #endif
 #include <string.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/time.h>
 #include <sys/wait.h>
 #include <sys/stat.h>
 #include <sys/file.h>
 #ifdef HAVE_SYS_IOCTL_H
 #include <sys/ioctl.h>
 #endif
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
 #endif
 #ifdef HAVE_SYS_UN_H
 #include <sys/un.h>
 #endif
 #ifdef HAVE_SYS_SOCKIO_H
 #include <sys/sockio.h>
 #endif
 #ifdef HAVE_NET_IF_H
 #include <net/if.h>
 #endif
 #ifdef HAVE_NETINET_IN_H
 #include <netinet/in.h>
 #endif
 #ifdef HAVE_NET_IF_DL_H
 #include <net/if_dl.h>
 #endif
 #if defined(__linux__) && defined(HAVE_SYS_SYSCALL_H)
 #include <sys/syscall.h>
 #endif

 #include "uuidP.h"
 #include "uuidd.h"

 #ifdef HAVE_SRANDOM
 #define srand(x) 	srandom(x)
 #define rand() 		random()
 #endif

 #ifdef TLS
 #define THREAD_LOCAL static TLS
 #else
 #define THREAD_LOCAL static
 #endif

 #if defined(__linux__) && defined(__NR_gettid) && defined(HAVE_JRAND48)
 #define DO_JRAND_MIX
 THREAD_LOCAL unsigned short jrand_seed[3];
 #endif

 static int get_random_fd(void)
 {
 	struct timeval	tv;
 	static int	fd = -2;
 	int		i;

 	if (fd == -2) {
 		gettimeofday(&tv, 0);
 		fd = open("/dev/urandom", O_RDONLY);
 		if (fd == -1)
 			fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
 		if (fd >= 0) {
 			i = fcntl(fd, F_GETFD);
 			if (i >= 0)
 				fcntl(fd, F_SETFD, i | FD_CLOEXEC);
 		}
 		srand((getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
 #ifdef DO_JRAND_MIX
 		jrand_seed[0] = getpid() ^ (tv.tv_sec & 0xFFFF);
 		jrand_seed[1] = getppid() ^ (tv.tv_usec & 0xFFFF);
 		jrand_seed[2] = (tv.tv_sec ^ tv.tv_usec) >> 16;
 #endif
 	}
 	/* Crank the random number generator a few times */
 	gettimeofday(&tv, 0);
 	for (i = (tv.tv_sec ^ tv.tv_usec) & 0x1F; i > 0; i--)
 		rand();
 	return fd;
 }


 /*
  * Generate a series of random bytes.  Use /dev/urandom if possible,
  * and if not, use srandom/random.
  */
 static void get_random_bytes(void *buf, int nbytes)
 {
 	int i, n = nbytes, fd = get_random_fd();
 	int lose_counter = 0;
 	unsigned char *cp = (unsigned char *) buf;
 	unsigned short tmp_seed[3];

 	if (fd >= 0) {
 		while (n > 0) {
 			i = read(fd, cp, n);
 			if (i <= 0) {
 				if (lose_counter++ > 16)
 					break;
 				continue;
 			}
 			n -= i;
 			cp += i;
 			lose_counter = 0;
 		}
 	}

 	/*
 	 * We do this all the time, but this is the only source of
 	 * randomness if /dev/random/urandom is out to lunch.
 	 */
 	for (cp = buf, i = 0; i < nbytes; i++)
 		*cp++ ^= (rand() >> 7) & 0xFF;
 #ifdef DO_JRAND_MIX
 	memcpy(tmp_seed, jrand_seed, sizeof(tmp_seed));
 	jrand_seed[2] = jrand_seed[2] ^ syscall(__NR_gettid);
 	for (cp = buf, i = 0; i < nbytes; i++)
 		*cp++ ^= (jrand48(tmp_seed) >> 7) & 0xFF;
 	memcpy(jrand_seed, tmp_seed,
 	       sizeof(jrand_seed)-sizeof(unsigned short));
 #endif

 	return;
 }

 /*
  * Get the ethernet hardware address, if we can find it...
  */
 static int get_node_id(unsigned char *node_id)
 {
 #ifdef HAVE_NET_IF_H
 	int 		sd;
 	struct ifreq 	ifr, *ifrp;
 	struct ifconf 	ifc;
 	char buf[1024];
 	int		n, i;
 	unsigned char 	*a;
 #ifdef HAVE_NET_IF_DL_H
 	struct sockaddr_dl *sdlp;
 #endif

 /*
  * BSD 4.4 defines the size of an ifreq to be
  * max(sizeof(ifreq), sizeof(ifreq.ifr_name)+ifreq.ifr_addr.sa_len
  * However, under earlier systems, sa_len isn't present, so the size is
  * just sizeof(struct ifreq)
  */
 #ifdef HAVE_SA_LEN
 #ifndef max
 #define max(a,b) ((a) > (b) ? (a) : (b))
 #endif
 #define ifreq_size(i) max(sizeof(struct ifreq),\
      sizeof((i).ifr_name)+(i).ifr_addr.sa_len)
 #else
 #define ifreq_size(i) sizeof(struct ifreq)
 #endif /* HAVE_SA_LEN*/

 	sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
 	if (sd < 0) {
 		return -1;
 	}
 	memset(buf, 0, sizeof(buf));
 	ifc.ifc_len = sizeof(buf);
 	ifc.ifc_buf = buf;
 	if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) {
 		close(sd);
 		return -1;
 	}
 	n = ifc.ifc_len;
 	for (i = 0; i < n; i+= ifreq_size(*ifrp) ) {
 		ifrp = (struct ifreq *)((char *) ifc.ifc_buf+i);
 		strncpy(ifr.ifr_name, ifrp->ifr_name, IFNAMSIZ);
 #ifdef SIOCGIFHWADDR
 		if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)
 			continue;
 		a = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
 #else
 #ifdef SIOCGENADDR
 		if (ioctl(sd, SIOCGENADDR, &ifr) < 0)
 			continue;
 		a = (unsigned char *) ifr.ifr_enaddr;
 #else
 #ifdef HAVE_NET_IF_DL_H
 		sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr;
 		if ((sdlp->sdl_family != AF_LINK) || (sdlp->sdl_alen != 6))
 			continue;
 		a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen];
 #else
 		/*
 		 * XXX we don't have a way of getting the hardware
 		 * address
 		 */
 		close(sd);
 		return 0;
 #endif /* HAVE_NET_IF_DL_H */
 #endif /* SIOCGENADDR */
 #endif /* SIOCGIFHWADDR */
 		if (!a[0] && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
 			continue;
 		if (node_id) {
 			memcpy(node_id, a, 6);
 			close(sd);
 			return 1;
 		}
 	}
 	close(sd);
 #endif
 	return 0;
 }

 /* Assume that the gettimeofday() has microsecond granularity */
 #define MAX_ADJUSTMENT 10

 static int get_clock(uint32_t *clock_high, uint32_t *clock_low,
 		     uint16_t *ret_clock_seq, int *num)
 {
 	THREAD_LOCAL int		adjustment = 0;
 	THREAD_LOCAL struct timeval	last = {0, 0};
 	THREAD_LOCAL int		state_fd = -2;
 	THREAD_LOCAL FILE		*state_f;
 	THREAD_LOCAL uint16_t		clock_seq;
 	struct timeval 			tv;
 	struct flock			fl;
 	unsigned long long		clock_reg;
 	mode_t				save_umask;

 	if (state_fd == -2) {
 		save_umask = umask(0);
 		state_fd = open("/var/lib/libuuid/clock.txt",
 				O_RDWR|O_CREAT, 0660);
 		(void) umask(save_umask);
 		state_f = fdopen(state_fd, "r+");
 		if (!state_f) {
 			close(state_fd);
 			state_fd = -1;
 		}
 	}
 	fl.l_type = F_WRLCK;
 	fl.l_whence = SEEK_SET;
 	fl.l_start = 0;
 	fl.l_len = 0;
 	fl.l_pid = 0;
 	if (state_fd >= 0) {
 		rewind(state_f);
 		while (fcntl(state_fd, F_SETLKW, &fl) < 0) {
 			if ((errno == EAGAIN) || (errno == EINTR))
 				continue;
 			fclose(state_f);
 			close(state_fd);
 			state_fd = -1;
 			break;
 		}
 	}
 	if (state_fd >= 0) {
 		unsigned int cl;
 		unsigned long tv1, tv2;
 		int a;

 		if (fscanf(state_f, "clock: %04x tv: %lu %lu adj: %d\n",
 			   &cl, &tv1, &tv2, &a) == 4) {
 			clock_seq = cl & 0x3FFF;
 			last.tv_sec = tv1;
 			last.tv_usec = tv2;
 			adjustment = a;
 		}
 	}

 	if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
 		get_random_bytes(&clock_seq, sizeof(clock_seq));
 		clock_seq &= 0x3FFF;
 		last = tv;
 		last.tv_sec--;
 	}

 try_again:
 	gettimeofday(&tv, 0);
 	if ((tv.tv_sec < last.tv_sec) ||
 	    ((tv.tv_sec == last.tv_sec) &&
 	     (tv.tv_usec < last.tv_usec))) {
 		clock_seq = (clock_seq+1) & 0x3FFF;
 		adjustment = 0;
 		last = tv;
 	} else if ((tv.tv_sec == last.tv_sec) &&
 	    (tv.tv_usec == last.tv_usec)) {
 		if (adjustment >= MAX_ADJUSTMENT)
 			goto try_again;
 		adjustment++;
 	} else {
 		adjustment = 0;
 		last = tv;
 	}

 	clock_reg = tv.tv_usec*10 + adjustment;
 	clock_reg += ((unsigned long long) tv.tv_sec)*10000000;
 	clock_reg += (((unsigned long long) 0x01B21DD2) << 32) + 0x13814000;

 	if (num && (*num > 1)) {
 		adjustment += *num - 1;
 		last.tv_usec += adjustment / 10;
 		adjustment = adjustment % 10;
 		last.tv_sec += last.tv_usec / 1000000;
 		last.tv_usec = last.tv_usec % 1000000;
 	}

 	if (state_fd > 0) {
 		rewind(state_f);
 		ftruncate(state_fd, 0);
 		fprintf(state_f, "clock: %04x tv: %lu %lu adj: %d\n",
 			clock_seq, last.tv_sec, last.tv_usec, adjustment);
 		fflush(state_f);
 		rewind(state_f);
 		fl.l_type = F_UNLCK;
 		fcntl(state_fd, F_SETLK, &fl);
 	}

 	*clock_high = clock_reg >> 32;
 	*clock_low = clock_reg;
 	*ret_clock_seq = clock_seq;
 	return 0;
 }

 static ssize_t read_all(int fd, char *buf, size_t count)
 {
 	ssize_t ret;
 	ssize_t c = 0;

 	memset(buf, 0, count);
 	while (count > 0) {
 		ret = read(fd, buf, count);
 		if (ret < 0) {
 			if ((errno == EAGAIN) || (errno == EINTR))
 				continue;
 			return -1;
 		}
 		count -= ret;
 		buf += ret;
 		c += ret;
 	}
 	return c;
 }


 /*
  * Try using the uuidd daemon to generate the UUID
  *
  * Returns 0 on success, non-zero on failure.
  */
 static int get_uuid_via_daemon(int op, uuid_t out, int *num)
 {
 #if defined(USE_UUIDD) && defined(HAVE_SYS_UN_H)
 	char op_buf[64];
 	int op_len;
 	int s;
 	ssize_t ret;
 	int32_t reply_len = 0, expected = 16;
 	struct sockaddr_un srv_addr;
 	pid_t pid;
 	static const char *uuidd_path = UUIDD_PATH;
 	static int access_ret = -2;
 	static int start_attempts = 0;

 	if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
 		return -1;

 	srv_addr.sun_family = AF_UNIX;
 	strcpy(srv_addr.sun_path, UUIDD_SOCKET_PATH);

 	if (connect(s, (const struct sockaddr *) &srv_addr,
 		    sizeof(struct sockaddr_un)) < 0) {
 		if (access_ret == -2)
 			access_ret = access(uuidd_path, X_OK);
 		if (access_ret == 0 && start_attempts++ < 5) {
 			if ((pid = fork()) == 0) {
 				execl(uuidd_path, "uuidd", "-qT", "300",
 				      (char *) NULL);
 				exit(1);
 			}
 			(void) waitpid(pid, 0, 0);
 			if (connect(s, (const struct sockaddr *) &srv_addr,
 				    sizeof(struct sockaddr_un)) < 0)
 				goto fail;
 		} else
 			goto fail;
 	}
 	op_buf[0] = op;
 	op_len = 1;
 	if (op == UUIDD_OP_BULK_TIME_UUID) {
 		memcpy(op_buf+1, num, sizeof(*num));
 		op_len += sizeof(*num);
 		expected += sizeof(*num);
 	}

 	ret = write(s, op_buf, op_len);
 	if (ret < 1)
 		goto fail;

 	ret = read_all(s, (char *) &reply_len, sizeof(reply_len));
 	if (ret < 0)
 		goto fail;

 	if (reply_len != expected)
 		goto fail;

 	ret = read_all(s, op_buf, reply_len);

 	if (op == UUIDD_OP_BULK_TIME_UUID)
 		memcpy(op_buf+16, num, sizeof(int));

 	memcpy(out, op_buf, 16);

 	close(s);
 	return ((ret == expected) ? 0 : -1);

 fail:
 	close(s);
 #endif
 	return -1;
 }

 void uuid__generate_time(uuid_t out, int *num)
 {
 	static unsigned char node_id[6];
 	static int has_init = 0;
 	struct uuid uu;
 	uint32_t	clock_mid;

 	if (!has_init) {
 		if (get_node_id(node_id) <= 0) {
 			get_random_bytes(node_id, 6);
 			/*
 			 * Set multicast bit, to prevent conflicts
 			 * with IEEE 802 addresses obtained from
 			 * network cards
 			 */
 			node_id[0] |= 0x01;
 		}
 		has_init = 1;
 	}
 	get_clock(&clock_mid, &uu.time_low, &uu.clock_seq, num);
 	uu.clock_seq |= 0x8000;
 	uu.time_mid = (uint16_t) clock_mid;
 	uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) | 0x1000;
 	memcpy(uu.node, node_id, 6);
 	uuid_pack(&uu, out);
 }

 void uuid_generate_time(uuid_t out)
 {
 #ifdef TLS
 	THREAD_LOCAL int		num = 0;
 	THREAD_LOCAL struct uuid	uu;
 	THREAD_LOCAL time_t		last_time = 0;
 	time_t				now;

 	if (num > 0) {
 		now = time(0);
 		if (now > last_time+1)
 			num = 0;
 	}
 	if (num <= 0) {
 		num = 1000;
 		if (get_uuid_via_daemon(UUIDD_OP_BULK_TIME_UUID,
 					out, &num) == 0) {
 			last_time = time(0);
 			uuid_unpack(out, &uu);
 			num--;
 			return;
 		}
 		num = 0;
 	}
 	if (num > 0) {
 		uu.time_low++;
 		if (uu.time_low == 0) {
 			uu.time_mid++;
 			if (uu.time_mid == 0)
 				uu.time_hi_and_version++;
 		}
 		num--;
 		uuid_pack(&uu, out);
 		return;
 	}
 #else
 	if (get_uuid_via_daemon(UUIDD_OP_TIME_UUID, out, 0) == 0)
 		return;
 #endif

 	uuid__generate_time(out, 0);
 }


 void uuid__generate_random(uuid_t out, int *num)
 {
 	uuid_t	buf;
 	struct uuid uu;
 	int i, n;

 	if (!num || !*num)
 		n = 1;
 	else
 		n = *num;

 	for (i = 0; i < n; i++) {
 		get_random_bytes(buf, sizeof(buf));
 		uuid_unpack(buf, &uu);

 		uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
 		uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF)
 			| 0x4000;
 		uuid_pack(&uu, out);
 		out += sizeof(uuid_t);
 	}
 }

 void uuid_generate_random(uuid_t out)
 {
 	int	num = 1;
 	/* No real reason to use the daemon for random uuid's -- yet */

 	uuid__generate_random(out, &num);
 }


 /*
  * This is the generic front-end to uuid_generate_random and
  * uuid_generate_time.  It uses uuid_generate_random only if
  * /dev/urandom is available, since otherwise we won't have
  * high-quality randomness.
  */
 void uuid_generate(uuid_t out)
 {
 	if (get_random_fd() >= 0)
 		uuid_generate_random(out);
 	else
 		uuid_generate_time(out);
 }
	/*
	* gen_uuid.c --- generate a DCE-compatible uuid
	*
	* Copyright (C) 1996, 1997, 1998, 1999 Theodore Ts'o.
	*
	* %Begin-Header%
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, and the entire permission notice in its entirety,
	* including the disclaimer of warranties.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* 3. The name of the author may not be used to endorse or promote
	* products derived from this software without specific prior
	* written permission.
	*
	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
	* WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
	* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
	* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
	* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
	* USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
	* DAMAGE.
	* %End-Header%
	*/

	/*
	* Force inclusion of SVID stuff since we need it if we're compiling in
	* gcc-wall wall mode
	*/
	#define _SVID_SOURCE

	#include <stdio.h>
	#ifdef HAVE_UNISTD_H
	#include <unistd.h>
	#endif
	#ifdef HAVE_STDLIB_H
	#include <stdlib.h>
	#endif
	#include <string.h>
	#include <fcntl.h>
	#include <errno.h>
	#include <sys/types.h>
	#include <sys/time.h>
	#include <sys/wait.h>
	#include <sys/stat.h>
	#include <sys/file.h>
	#ifdef HAVE_SYS_IOCTL_H
	#include <sys/ioctl.h>
	#endif
	#ifdef HAVE_SYS_SOCKET_H
	#include <sys/socket.h>
	#endif
	#ifdef HAVE_SYS_UN_H
	#include <sys/un.h>
	#endif
	#ifdef HAVE_SYS_SOCKIO_H
	#include <sys/sockio.h>
	#endif
	#ifdef HAVE_NET_IF_H
	#include <net/if.h>
	#endif
	#ifdef HAVE_NETINET_IN_H
	#include <netinet/in.h>
	#endif
	#ifdef HAVE_NET_IF_DL_H
	#include <net/if_dl.h>
	#endif
	#if defined(__linux__) && defined(HAVE_SYS_SYSCALL_H)
	#include <sys/syscall.h>
	#endif

	#include "uuidP.h"
	#include "uuidd.h"

	#ifdef HAVE_SRANDOM
	#define srand(x) srandom(x)
	#define rand() random()
	#endif

	#ifdef TLS
	#define THREAD_LOCAL static TLS
	#else
	#define THREAD_LOCAL static
	#endif

	#if defined(__linux__) && defined(__NR_gettid) && defined(HAVE_JRAND48)
	#define DO_JRAND_MIX
	THREAD_LOCAL unsigned short jrand_seed[3];
	#endif

	static int get_random_fd(void)
	{
	struct timeval tv;
	static int fd = -2;
	int i;

	if (fd == -2) {
	gettimeofday(&tv, 0);
	fd = open("/dev/urandom", O_RDONLY);
	if (fd == -1)
	fd = open("/dev/random", O_RDONLY \| O_NONBLOCK);
	if (fd >= 0) {
	i = fcntl(fd, F_GETFD);
	if (i >= 0)
	fcntl(fd, F_SETFD, i \| FD_CLOEXEC);
	}
	srand((getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
	#ifdef DO_JRAND_MIX
	jrand_seed[0] = getpid() ^ (tv.tv_sec & 0xFFFF);
	jrand_seed[1] = getppid() ^ (tv.tv_usec & 0xFFFF);
	jrand_seed[2] = (tv.tv_sec ^ tv.tv_usec) >> 16;
	#endif
	}
	/* Crank the random number generator a few times */
	gettimeofday(&tv, 0);
	for (i = (tv.tv_sec ^ tv.tv_usec) & 0x1F; i > 0; i--)
	rand();
	return fd;
	}


	/*
	* Generate a series of random bytes. Use /dev/urandom if possible,
	* and if not, use srandom/random.
	*/
	static void get_random_bytes(void *buf, int nbytes)
	{
	int i, n = nbytes, fd = get_random_fd();
	int lose_counter = 0;
	unsigned char cp = (unsigned char ) buf;
	unsigned short tmp_seed[3];

	if (fd >= 0) {
	while (n > 0) {
	i = read(fd, cp, n);
	if (i <= 0) {
	if (lose_counter++ > 16)
	break;
	continue;
	}
	n -= i;
	cp += i;
	lose_counter = 0;
	}
	}

	/*
	* We do this all the time, but this is the only source of
	* randomness if /dev/random/urandom is out to lunch.
	*/
	for (cp = buf, i = 0; i < nbytes; i++)
	*cp++ ^= (rand() >> 7) & 0xFF;
	#ifdef DO_JRAND_MIX
	memcpy(tmp_seed, jrand_seed, sizeof(tmp_seed));
	jrand_seed[2] = jrand_seed[2] ^ syscall(__NR_gettid);
	for (cp = buf, i = 0; i < nbytes; i++)
	*cp++ ^= (jrand48(tmp_seed) >> 7) & 0xFF;
	memcpy(jrand_seed, tmp_seed,
	sizeof(jrand_seed)-sizeof(unsigned short));
	#endif

	return;
	}

	/*
	* Get the ethernet hardware address, if we can find it...
	*/
	static int get_node_id(unsigned char *node_id)
	{
	#ifdef HAVE_NET_IF_H
	int sd;
	struct ifreq ifr, *ifrp;
	struct ifconf ifc;
	char buf[1024];
	int n, i;
	unsigned char *a;
	#ifdef HAVE_NET_IF_DL_H
	struct sockaddr_dl *sdlp;
	#endif

	/*
	* BSD 4.4 defines the size of an ifreq to be
	* max(sizeof(ifreq), sizeof(ifreq.ifr_name)+ifreq.ifr_addr.sa_len
	* However, under earlier systems, sa_len isn't present, so the size is
	* just sizeof(struct ifreq)
	*/
	#ifdef HAVE_SA_LEN
	#ifndef max
	#define max(a,b) ((a) > (b) ? (a) : (b))
	#endif
	#define ifreq_size(i) max(sizeof(struct ifreq),\
	sizeof((i).ifr_name)+(i).ifr_addr.sa_len)
	#else
	#define ifreq_size(i) sizeof(struct ifreq)
	#endif /* HAVE_SA_LEN*/

	sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
	if (sd < 0) {
	return -1;
	}
	memset(buf, 0, sizeof(buf));
	ifc.ifc_len = sizeof(buf);
	ifc.ifc_buf = buf;
	if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) {
	close(sd);
	return -1;
	}
	n = ifc.ifc_len;
	for (i = 0; i < n; i+= ifreq_size(*ifrp) ) {
	ifrp = (struct ifreq )((char ) ifc.ifc_buf+i);
	strncpy(ifr.ifr_name, ifrp->ifr_name, IFNAMSIZ);
	#ifdef SIOCGIFHWADDR
	if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)
	continue;
	a = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
	#else
	#ifdef SIOCGENADDR
	if (ioctl(sd, SIOCGENADDR, &ifr) < 0)
	continue;
	a = (unsigned char *) ifr.ifr_enaddr;
	#else
	#ifdef HAVE_NET_IF_DL_H
	sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr;
	if ((sdlp->sdl_family != AF_LINK) \|\| (sdlp->sdl_alen != 6))
	continue;
	a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen];
	#else
	/*
	* XXX we don't have a way of getting the hardware
	* address
	*/
	close(sd);
	return 0;
	#endif /* HAVE_NET_IF_DL_H */
	#endif /* SIOCGENADDR */
	#endif /* SIOCGIFHWADDR */
	if (!a[0] && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
	continue;
	if (node_id) {
	memcpy(node_id, a, 6);
	close(sd);
	return 1;
	}
	}
	close(sd);
	#endif
	return 0;
	}

	/* Assume that the gettimeofday() has microsecond granularity */
	#define MAX_ADJUSTMENT 10

	static int get_clock(uint32_t clock_high, uint32_t clock_low,
	uint16_t ret_clock_seq, int num)
	{
	THREAD_LOCAL int adjustment = 0;
	THREAD_LOCAL struct timeval last = {0, 0};
	THREAD_LOCAL int state_fd = -2;
	THREAD_LOCAL FILE *state_f;
	THREAD_LOCAL uint16_t clock_seq;
	struct timeval tv;
	struct flock fl;
	unsigned long long clock_reg;
	mode_t save_umask;

	if (state_fd == -2) {
	save_umask = umask(0);
	state_fd = open("/var/lib/libuuid/clock.txt",
	O_RDWR\|O_CREAT, 0660);
	(void) umask(save_umask);
	state_f = fdopen(state_fd, "r+");
	if (!state_f) {
	close(state_fd);
	state_fd = -1;
	}
	}
	fl.l_type = F_WRLCK;
	fl.l_whence = SEEK_SET;
	fl.l_start = 0;
	fl.l_len = 0;
	fl.l_pid = 0;
	if (state_fd >= 0) {
	rewind(state_f);
	while (fcntl(state_fd, F_SETLKW, &fl) < 0) {
	if ((errno == EAGAIN) \|\| (errno == EINTR))
	continue;
	fclose(state_f);
	close(state_fd);
	state_fd = -1;
	break;
	}
	}
	if (state_fd >= 0) {
	unsigned int cl;
	unsigned long tv1, tv2;
	int a;

	if (fscanf(state_f, "clock: %04x tv: %lu %lu adj: %d\n",
	&cl, &tv1, &tv2, &a) == 4) {
	clock_seq = cl & 0x3FFF;
	last.tv_sec = tv1;
	last.tv_usec = tv2;
	adjustment = a;
	}
	}

	if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
	get_random_bytes(&clock_seq, sizeof(clock_seq));
	clock_seq &= 0x3FFF;
	last = tv;
	last.tv_sec--;
	}

	try_again:
	gettimeofday(&tv, 0);
	if ((tv.tv_sec < last.tv_sec) \|\|
	((tv.tv_sec == last.tv_sec) &&
	(tv.tv_usec < last.tv_usec))) {
	clock_seq = (clock_seq+1) & 0x3FFF;
	adjustment = 0;
	last = tv;
	} else if ((tv.tv_sec == last.tv_sec) &&
	(tv.tv_usec == last.tv_usec)) {
	if (adjustment >= MAX_ADJUSTMENT)
	goto try_again;
	adjustment++;
	} else {
	adjustment = 0;
	last = tv;
	}

	clock_reg = tv.tv_usec*10 + adjustment;
	clock_reg += ((unsigned long long) tv.tv_sec)*10000000;
	clock_reg += (((unsigned long long) 0x01B21DD2) << 32) + 0x13814000;

	if (num && (*num > 1)) {
	adjustment += *num - 1;
	last.tv_usec += adjustment / 10;
	adjustment = adjustment % 10;
	last.tv_sec += last.tv_usec / 1000000;
	last.tv_usec = last.tv_usec % 1000000;
	}

	if (state_fd > 0) {
	rewind(state_f);
	ftruncate(state_fd, 0);
	fprintf(state_f, "clock: %04x tv: %lu %lu adj: %d\n",
	clock_seq, last.tv_sec, last.tv_usec, adjustment);
	fflush(state_f);
	rewind(state_f);
	fl.l_type = F_UNLCK;
	fcntl(state_fd, F_SETLK, &fl);
	}

	*clock_high = clock_reg >> 32;
	*clock_low = clock_reg;
	*ret_clock_seq = clock_seq;
	return 0;
	}

	static ssize_t read_all(int fd, char *buf, size_t count)
	{
	ssize_t ret;
	ssize_t c = 0;

	memset(buf, 0, count);
	while (count > 0) {
	ret = read(fd, buf, count);
	if (ret < 0) {
	if ((errno == EAGAIN) \|\| (errno == EINTR))
	continue;
	return -1;
	}
	count -= ret;
	buf += ret;
	c += ret;
	}
	return c;
	}


	/*
	* Try using the uuidd daemon to generate the UUID
	*
	* Returns 0 on success, non-zero on failure.
	*/
	static int get_uuid_via_daemon(int op, uuid_t out, int *num)
	{
	#if defined(USE_UUIDD) && defined(HAVE_SYS_UN_H)
	char op_buf[64];
	int op_len;
	int s;
	ssize_t ret;
	int32_t reply_len = 0, expected = 16;
	struct sockaddr_un srv_addr;
	pid_t pid;
	static const char *uuidd_path = UUIDD_PATH;
	static int access_ret = -2;
	static int start_attempts = 0;

	if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
	return -1;

	srv_addr.sun_family = AF_UNIX;
	strcpy(srv_addr.sun_path, UUIDD_SOCKET_PATH);

	if (connect(s, (const struct sockaddr *) &srv_addr,
	sizeof(struct sockaddr_un)) < 0) {
	if (access_ret == -2)
	access_ret = access(uuidd_path, X_OK);
	if (access_ret == 0 && start_attempts++ < 5) {
	if ((pid = fork()) == 0) {
	execl(uuidd_path, "uuidd", "-qT", "300",
	(char *) NULL);
	exit(1);
	}
	(void) waitpid(pid, 0, 0);
	if (connect(s, (const struct sockaddr *) &srv_addr,
	sizeof(struct sockaddr_un)) < 0)
	goto fail;
	} else
	goto fail;
	}
	op_buf[0] = op;
	op_len = 1;
	if (op == UUIDD_OP_BULK_TIME_UUID) {
	memcpy(op_buf+1, num, sizeof(*num));
	op_len += sizeof(*num);
	expected += sizeof(*num);
	}

	ret = write(s, op_buf, op_len);
	if (ret < 1)
	goto fail;

	ret = read_all(s, (char *) &reply_len, sizeof(reply_len));
	if (ret < 0)
	goto fail;

	if (reply_len != expected)
	goto fail;

	ret = read_all(s, op_buf, reply_len);

	if (op == UUIDD_OP_BULK_TIME_UUID)
	memcpy(op_buf+16, num, sizeof(int));

	memcpy(out, op_buf, 16);

	close(s);
	return ((ret == expected) ? 0 : -1);

	fail:
	close(s);
	#endif
	return -1;
	}

	void uuid__generate_time(uuid_t out, int *num)
	{
	static unsigned char node_id[6];
	static int has_init = 0;
	struct uuid uu;
	uint32_t clock_mid;

	if (!has_init) {
	if (get_node_id(node_id) <= 0) {
	get_random_bytes(node_id, 6);
	/*
	* Set multicast bit, to prevent conflicts
	* with IEEE 802 addresses obtained from
	* network cards
	*/
	node_id[0] \|= 0x01;
	}
	has_init = 1;
	}
	get_clock(&clock_mid, &uu.time_low, &uu.clock_seq, num);
	uu.clock_seq \|= 0x8000;
	uu.time_mid = (uint16_t) clock_mid;
	uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) \| 0x1000;
	memcpy(uu.node, node_id, 6);
	uuid_pack(&uu, out);
	}

	void uuid_generate_time(uuid_t out)
	{
	#ifdef TLS
	THREAD_LOCAL int num = 0;
	THREAD_LOCAL struct uuid uu;
	THREAD_LOCAL time_t last_time = 0;
	time_t now;

	if (num > 0) {
	now = time(0);
	if (now > last_time+1)
	num = 0;
	}
	if (num <= 0) {
	num = 1000;
	if (get_uuid_via_daemon(UUIDD_OP_BULK_TIME_UUID,
	out, &num) == 0) {
	last_time = time(0);
	uuid_unpack(out, &uu);
	num--;
	return;
	}
	num = 0;
	}
	if (num > 0) {
	uu.time_low++;
	if (uu.time_low == 0) {
	uu.time_mid++;
	if (uu.time_mid == 0)
	uu.time_hi_and_version++;
	}
	num--;
	uuid_pack(&uu, out);
	return;
	}
	#else
	if (get_uuid_via_daemon(UUIDD_OP_TIME_UUID, out, 0) == 0)
	return;
	#endif

	uuid__generate_time(out, 0);
	}


	void uuid__generate_random(uuid_t out, int *num)
	{
	uuid_t buf;
	struct uuid uu;
	int i, n;

	if (!num \|\| !*num)
	n = 1;
	else
	n = *num;

	for (i = 0; i < n; i++) {
	get_random_bytes(buf, sizeof(buf));
	uuid_unpack(buf, &uu);

	uu.clock_seq = (uu.clock_seq & 0x3FFF) \| 0x8000;
	uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF)
	\| 0x4000;
	uuid_pack(&uu, out);
	out += sizeof(uuid_t);
	}
	}

	void uuid_generate_random(uuid_t out)
	{
	int num = 1;
	/* No real reason to use the daemon for random uuid's -- yet */

	uuid__generate_random(out, &num);
	}


	/*
	* This is the generic front-end to uuid_generate_random and
	* uuid_generate_time. It uses uuid_generate_random only if
	* /dev/urandom is available, since otherwise we won't have
	* high-quality randomness.
	*/
	void uuid_generate(uuid_t out)
	{
	if (get_random_fd() >= 0)
	uuid_generate_random(out);
	else
	uuid_generate_time(out);
	}