uuid.c

利用C语言实现的人工智能系统

/*
 * UUID.
 * 
 * Copyright (C) 1996, 1997, 1998 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%
 */

#include "uuid.h"

#ifdef HAVE_SRANDOM
#define srand(x) 	srandom(x)
#define rand() 		random()
#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);
	}
	/* 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;

	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 = (unsigned char *)buf, i = 0; i < nbytes; i++)
		*cp++ ^= (rand() >> 7) & 0xFF;
	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;
}

static int get_clock(uint32_t *clock_high, uint32_t *clock_low, uint16_t *ret_clock_seq)
{
	static int			adjustment = 0;
	static struct timeval		last = {0, 0};
	static uint16_t			clock_seq;
	struct timeval 			tv;
	unsigned long long		clock_reg;
	
try_again:
	gettimeofday(&tv, 0);
	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--;
	}
	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;

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

void uuid_generate_time(uuid_t out)
{
	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);
	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_random(uuid_t out)
{
	uuid_t	buf;
	struct uuid uu;

	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);
}

/*
 * 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);
}

void uuid_clear(uuid_t uu)
{
	memset(uu, 0, 16);
}

int uuid_compare_binary(const uuid_t uu1, const uuid_t uu2)
{
	struct uuid	uuid1, uuid2;

	uuid_unpack(uu1, &uuid1);
	uuid_unpack(uu2, &uuid2);

	UUCMP(uuid1.time_low, uuid2.time_low);
	UUCMP(uuid1.time_mid, uuid2.time_mid);
	UUCMP(uuid1.time_hi_and_version, uuid2.time_hi_and_version);
	UUCMP(uuid1.clock_seq, uuid2.clock_seq);
	return memcmp(uuid1.node, uuid2.node, 6);
}

void uuid_copy(uuid_t dst, const uuid_t src)
{
	unsigned char		*cp1;
	const unsigned char	*cp2;
	int			i;

	for (i=0, cp1 = dst, cp2 = src; i < 16; i++)
		*cp1++ = *cp2++;
}

int uuid_is_null(const uuid_t uu)
{
	/* Returns 1 if the uuid is the NULL uuid */
	const unsigned char 	*cp;
	int			i;

	for (i=0, cp = uu; i < 16; i++)
		if (*cp++)
			return 0;
	return 1;
}

void uuid_pack(const struct uuid *uu, uuid_t ptr)
{
	uint32_t	tmp;
	unsigned char	*out = ptr;

	tmp = uu->time_low;
	out[3] = (unsigned char) tmp;
	tmp >>= 8;
	out[2] = (unsigned char) tmp;
	tmp >>= 8;
	out[1] = (unsigned char) tmp;
	tmp >>= 8;
	out[0] = (unsigned char) tmp;
	
	tmp = uu->time_mid;
	out[5] = (unsigned char) tmp;
	tmp >>= 8;
	out[4] = (unsigned char) tmp;

	tmp = uu->time_hi_and_version;
	out[7] = (unsigned char) tmp;
	tmp >>= 8;
	out[6] = (unsigned char) tmp;

	tmp = uu->clock_seq;
	out[9] = (unsigned char) tmp;
	tmp >>= 8;
	out[8] = (unsigned char) tmp;

	memcpy(out+10, uu->node, 6);
}

int uuid_parse(const char *in, uuid_t uu)
{
	struct uuid	uuid;
	int 		i;
	const char	*cp;
	char		buf[3];

	if (strlen(in) != 36)
		return -1;
	for (i=0, cp = in; i <= 36; i++,cp++) {
		if ((i == 8) || (i == 13) || (i == 18) ||
		    (i == 23)) {
			if (*cp == '-')
				continue;
			else
				return -1;
		}
		if (i== 36)
			if (*cp == 0)
				continue;
		if (!isxdigit(*cp))
			return -1;
	}
	uuid.time_low = strtoul(in, NULL, 16);
	uuid.time_mid = strtoul(in+9, NULL, 16);
	uuid.time_hi_and_version = strtoul(in+14, NULL, 16);
	uuid.clock_seq = strtoul(in+19, NULL, 16);
	cp = in+24;
	buf[2] = 0;
	for (i=0; i < 6; i++) {
		buf[0] = *cp++;
		buf[1] = *cp++;
		uuid.node[i] = strtoul(buf, NULL, 16);
	}
	
	uuid_pack(&uuid, uu);
	return 0;
}

void uuid_unpack(const uuid_t in, struct uuid *uu)
{
	const uint8_t	*ptr = in;
	uint32_t		tmp;

	tmp = *ptr++;
	tmp = (tmp << 8) | *ptr++;
	tmp = (tmp << 8) | *ptr++;
	tmp = (tmp << 8) | *ptr++;
	uu->time_low = tmp;

	tmp = *ptr++;
	tmp = (tmp << 8) | *ptr++;
	uu->time_mid = tmp;
	
	tmp = *ptr++;
	tmp = (tmp << 8) | *ptr++;
	uu->time_hi_and_version = tmp;

	tmp = *ptr++;
	tmp = (tmp << 8) | *ptr++;
	uu->clock_seq = tmp;

	memcpy(uu->node, ptr, 6);
}

static void uuid_unparse_x(const uuid_t uu, char *out, const char *fmt)
{
	struct uuid uuid;

	uuid_unpack(uu, &uuid);
	sprintf(out, fmt,
		uuid.time_low, uuid.time_mid, uuid.time_hi_and_version,
		uuid.clock_seq >> 8, uuid.clock_seq & 0xFF,
		uuid.node[0], uuid.node[1], uuid.node[2],
		uuid.node[3], uuid.node[4], uuid.node[5]);
}

void uuid_unparse_lower(const uuid_t uu, char *out)
{
	uuid_unparse_x(uu, out,	fmt_lower);
}

void uuid_unparse_upper(const uuid_t uu, char *out)
{
	uuid_unparse_x(uu, out,	fmt_upper);
}

void uuid_unparse(const uuid_t uu, char *out)
{
	uuid_unparse_x(uu, out, FMT_DEFAULT);
}

void uuid_create(char *uuid)
{
	/* creates a new UUID in a string format without the dash "-" */
	unsigned char buf_uuid[16];
	
    uuid_generate(buf_uuid);
    uuid_unparse(buf_uuid, uuid);
}

int uuid_compare(char *uuid1, char *uuid2)
{
	/* compares two UUID's in string format */
	return strcmp(uuid1, uuid2);
}