source: MondoRescue/branches/stable/mindi-busybox/e2fsprogs/uuid/gen_uuid.c @ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 13 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)

File size: 7.5 KB
Line 
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 <unistd.h>
36#include <stdlib.h>
37#include <string.h>
38#include <fcntl.h>
39#include <errno.h>
40#include <sys/types.h>
41#include <sys/stat.h>
42#include <sys/file.h>
43#ifdef HAVE_SYS_IOCTL_H
44#include <sys/ioctl.h>
45#endif
46#include <sys/socket.h>
47#ifdef HAVE_SYS_SOCKIO_H
48#include <sys/sockio.h>
49#endif
50#ifdef HAVE_NET_IF_H
51#include <net/if.h>
52#endif
53#ifdef HAVE_NETINET_IN_H
54#include <netinet/in.h>
55#endif
56#ifdef HAVE_NET_IF_DL_H
57#include <net/if_dl.h>
58#endif
59
60#include "uuidP.h"
61
62#ifdef HAVE_SRANDOM
63#define srand(x)    srandom(x)
64#define rand()      random()
65#endif
66
67static int get_random_fd(void)
68{
69    struct timeval  tv;
70    static int  fd = -2;
71    int     i;
72
73    if (fd == -2) {
74        gettimeofday(&tv, 0);
75        fd = open("/dev/urandom", O_RDONLY);
76        if (fd == -1)
77            fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
78        srand((getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
79    }
80    /* Crank the random number generator a few times */
81    gettimeofday(&tv, 0);
82    for (i = (tv.tv_sec ^ tv.tv_usec) & 0x1F; i > 0; i--)
83        rand();
84    return fd;
85}
86
87
88/*
89 * Generate a series of random bytes.  Use /dev/urandom if possible,
90 * and if not, use srandom/random.
91 */
92static void get_random_bytes(void *buf, int nbytes)
93{
94    int i, n = nbytes, fd = get_random_fd();
95    int lose_counter = 0;
96    unsigned char *cp = (unsigned char *) buf;
97
98    if (fd >= 0) {
99        while (n > 0) {
100            i = read(fd, cp, n);
101            if (i <= 0) {
102                if (lose_counter++ > 16)
103                    break;
104                continue;
105            }
106            n -= i;
107            cp += i;
108            lose_counter = 0;
109        }
110    }
111
112    /*
113     * We do this all the time, but this is the only source of
114     * randomness if /dev/random/urandom is out to lunch.
115     */
116    for (cp = buf, i = 0; i < nbytes; i++)
117        *cp++ ^= (rand() >> 7) & 0xFF;
118    return;
119}
120
121/*
122 * Get the ethernet hardware address, if we can find it...
123 */
124static int get_node_id(unsigned char *node_id)
125{
126#ifdef HAVE_NET_IF_H
127    int     sd;
128    struct ifreq    ifr, *ifrp;
129    struct ifconf   ifc;
130    char buf[1024];
131    int     n, i;
132    unsigned char   *a;
133#ifdef HAVE_NET_IF_DL_H
134    struct sockaddr_dl *sdlp;
135#endif
136
137/*
138 * BSD 4.4 defines the size of an ifreq to be
139 * max(sizeof(ifreq), sizeof(ifreq.ifr_name)+ifreq.ifr_addr.sa_len
140 * However, under earlier systems, sa_len isn't present, so the size is
141 * just sizeof(struct ifreq)
142 */
143#ifdef HAVE_SA_LEN
144#ifndef max
145#define max(a,b) ((a) > (b) ? (a) : (b))
146#endif
147#define ifreq_size(i) max(sizeof(struct ifreq),\
148     sizeof((i).ifr_name)+(i).ifr_addr.sa_len)
149#else
150#define ifreq_size(i) sizeof(struct ifreq)
151#endif /* HAVE_SA_LEN*/
152
153    sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
154    if (sd < 0) {
155        return -1;
156    }
157    memset(buf, 0, sizeof(buf));
158    ifc.ifc_len = sizeof(buf);
159    ifc.ifc_buf = buf;
160    if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) {
161        close(sd);
162        return -1;
163    }
164    n = ifc.ifc_len;
165    for (i = 0; i < n; i+= ifreq_size(*ifrp) ) {
166        ifrp = (struct ifreq *)((char *) ifc.ifc_buf+i);
167        strncpy(ifr.ifr_name, ifrp->ifr_name, IFNAMSIZ);
168#ifdef SIOCGIFHWADDR
169        if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)
170            continue;
171        a = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
172#else
173#ifdef SIOCGENADDR
174        if (ioctl(sd, SIOCGENADDR, &ifr) < 0)
175            continue;
176        a = (unsigned char *) ifr.ifr_enaddr;
177#else
178#ifdef HAVE_NET_IF_DL_H
179        sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr;
180        if ((sdlp->sdl_family != AF_LINK) || (sdlp->sdl_alen != 6))
181            continue;
182        a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen];
183#else
184        /*
185         * XXX we don't have a way of getting the hardware
186         * address
187         */
188        close(sd);
189        return 0;
190#endif /* HAVE_NET_IF_DL_H */
191#endif /* SIOCGENADDR */
192#endif /* SIOCGIFHWADDR */
193        if (!a[0] && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
194            continue;
195        if (node_id) {
196            memcpy(node_id, a, 6);
197            close(sd);
198            return 1;
199        }
200    }
201    close(sd);
202#endif
203    return 0;
204}
205
206/* Assume that the gettimeofday() has microsecond granularity */
207#define MAX_ADJUSTMENT 10
208
209static int get_clock(uint32_t *clock_high, uint32_t *clock_low, uint16_t *ret_clock_seq)
210{
211    static int          adjustment = 0;
212    static struct timeval       last = {0, 0};
213    static uint16_t         clock_seq;
214    struct timeval          tv;
215    unsigned long long      clock_reg;
216
217try_again:
218    gettimeofday(&tv, 0);
219    if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
220        get_random_bytes(&clock_seq, sizeof(clock_seq));
221        clock_seq &= 0x3FFF;
222        last = tv;
223        last.tv_sec--;
224    }
225    if ((tv.tv_sec < last.tv_sec) ||
226        ((tv.tv_sec == last.tv_sec) &&
227         (tv.tv_usec < last.tv_usec))) {
228        clock_seq = (clock_seq+1) & 0x3FFF;
229        adjustment = 0;
230        last = tv;
231    } else if ((tv.tv_sec == last.tv_sec) &&
232        (tv.tv_usec == last.tv_usec)) {
233        if (adjustment >= MAX_ADJUSTMENT)
234            goto try_again;
235        adjustment++;
236    } else {
237        adjustment = 0;
238        last = tv;
239    }
240
241    clock_reg = tv.tv_usec*10 + adjustment;
242    clock_reg += ((unsigned long long) tv.tv_sec)*10000000;
243    clock_reg += (((unsigned long long) 0x01B21DD2) << 32) + 0x13814000;
244
245    *clock_high = clock_reg >> 32;
246    *clock_low = clock_reg;
247    *ret_clock_seq = clock_seq;
248    return 0;
249}
250
251void uuid_generate_time(uuid_t out)
252{
253    static unsigned char node_id[6];
254    static int has_init = 0;
255    struct uuid uu;
256    uint32_t    clock_mid;
257
258    if (!has_init) {
259        if (get_node_id(node_id) <= 0) {
260            get_random_bytes(node_id, 6);
261            /*
262             * Set multicast bit, to prevent conflicts
263             * with IEEE 802 addresses obtained from
264             * network cards
265             */
266            node_id[0] |= 0x01;
267        }
268        has_init = 1;
269    }
270    get_clock(&clock_mid, &uu.time_low, &uu.clock_seq);
271    uu.clock_seq |= 0x8000;
272    uu.time_mid = (uint16_t) clock_mid;
273    uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) | 0x1000;
274    memcpy(uu.node, node_id, 6);
275    uuid_pack(&uu, out);
276}
277
278void uuid_generate_random(uuid_t out)
279{
280    uuid_t  buf;
281    struct uuid uu;
282
283    get_random_bytes(buf, sizeof(buf));
284    uuid_unpack(buf, &uu);
285
286    uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
287    uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF) | 0x4000;
288    uuid_pack(&uu, out);
289}
290
291/*
292 * This is the generic front-end to uuid_generate_random and
293 * uuid_generate_time.  It uses uuid_generate_random only if
294 * /dev/urandom is available, since otherwise we won't have
295 * high-quality randomness.
296 */
297void uuid_generate(uuid_t out)
298{
299    if (get_random_fd() >= 0)
300        uuid_generate_random(out);
301    else
302        uuid_generate_time(out);
303}
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