src/libs/uuid/gen_uuid.c

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