lib/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 /*
  36  * Force inclusion of SVID stuff since we need it if we're compiling in
  37  * gcc-wall wall mode
  38  */
  39 #define _SVID_SOURCE
  40
  41 #ifdef _WIN32
  42 #define _WIN32_WINNT 0x0500
  43 #include <windows.h>
  44 #define UUID MYUUID
  45 #endif
  46 #include <stdio.h>
  47 #ifdef HAVE_UNISTD_H
  48 #include <unistd.h>
  49 #endif
  50 #ifdef HAVE_STDLIB_H
  51 #include <stdlib.h>
  52 #endif
  53 #include <string.h>
  54 #include <fcntl.h>
  55 #include <errno.h>
  56 #include <sys/types.h>
  57 #ifdef HAVE_SYS_TIME_H
  58 #include <sys/time.h>
  59 #endif
  60 #include <sys/wait.h>
  61 #include <sys/stat.h>
  62 #ifdef HAVE_SYS_FILE_H
  63 #include <sys/file.h>
  64 #endif
  65 #ifdef HAVE_SYS_IOCTL_H
  66 #include <sys/ioctl.h>
  67 #endif
  68 #ifdef HAVE_SYS_SOCKET_H
  69 #include <sys/socket.h>
  70 #endif
  71 #ifdef HAVE_SYS_UN_H
  72 #include <sys/un.h>
  73 #endif
  74 #ifdef HAVE_SYS_SOCKIO_H
  75 #include <sys/sockio.h>
  76 #endif
  77 #ifdef HAVE_NET_IF_H
  78 #include <net/if.h>
  79 #endif
  80 #ifdef HAVE_NETINET_IN_H
  81 #include <netinet/in.h>
  82 #endif
  83 #ifdef HAVE_NET_IF_DL_H
  84 #include <net/if_dl.h>
  85 #endif
  86 #if defined(__linux__) && defined(HAVE_SYS_SYSCALL_H)
  87 #include <sys/syscall.h>
  88 #endif
  89
  90 #include "uuidP.h"
  91 #include "uuidd.h"
  92
  93 #ifdef HAVE_SRANDOM
  94 #define srand(x)        srandom(x)
  95 #define rand()          random()
  96 #endif
  97
  98 #ifdef TLS
  99 #define THREAD_LOCAL static TLS
 100 #else
 101 #define THREAD_LOCAL static
 102 #endif
 103
 104 #if defined(__linux__) && defined(__NR_gettid) && defined(HAVE_JRAND48)
 105 #define DO_JRAND_MIX
 106 THREAD_LOCAL unsigned short jrand_seed[3];
 107 #endif
 108
 109 #ifdef _WIN32
 110 static void gettimeofday (struct timeval *tv, void *dummy)
 111 {
 112         FILETIME        ftime;
 113         uint64_t        n;
 114
 115         GetSystemTimeAsFileTime (&ftime);
 116         n = (((uint64_t) ftime.dwHighDateTime << 32)
 117              + (uint64_t) ftime.dwLowDateTime);
 118         if (n) {
 119                 n /= 10;
 120                 n -= ((369 * 365 + 89) * (uint64_t) 86400) * 1000000;
 121         }
 122
 123         tv->tv_sec = n / 1000000;
 124         tv->tv_usec = n % 1000000;
 125 }
 126
 127 static int getuid (void)
 128 {
 129         return 1;
 130 }
 131 #endif
 132
 133 static int get_random_fd(void)
 134 {
 135         struct timeval  tv;
 136         static int      fd = -2;
 137         int             i;
 138
 139         if (fd == -2) {
 140                 gettimeofday(&tv, 0);
 141 #ifndef _WIN32
 142                 fd = open("/dev/urandom", O_RDONLY);
 143                 if (fd == -1)
 144                         fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
 145                 if (fd >= 0) {
 146                         i = fcntl(fd, F_GETFD);
 147                         if (i >= 0)
 148                                 fcntl(fd, F_SETFD, i | FD_CLOEXEC);
 149                 }
 150 #endif
 151                 srand((getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
 152 #ifdef DO_JRAND_MIX
 153                 jrand_seed[0] = getpid() ^ (tv.tv_sec & 0xFFFF);
 154                 jrand_seed[1] = getppid() ^ (tv.tv_usec & 0xFFFF);
 155                 jrand_seed[2] = (tv.tv_sec ^ tv.tv_usec) >> 16;
 156 #endif
 157         }
 158         /* Crank the random number generator a few times */
 159         gettimeofday(&tv, 0);
 160         for (i = (tv.tv_sec ^ tv.tv_usec) & 0x1F; i > 0; i--)
 161                 rand();
 162         return fd;
 163 }
 164
 165
 166 /*
 167  * Generate a series of random bytes.  Use /dev/urandom if possible,
 168  * and if not, use srandom/random.
 169  */
 170 static void get_random_bytes(void *buf, int nbytes)
 171 {
 172         int i, n = nbytes, fd = get_random_fd();
 173         int lose_counter = 0;
 174         unsigned char *cp = (unsigned char *) buf;
 175         unsigned short tmp_seed[3];
 176
 177         if (fd >= 0) {
 178                 while (n > 0) {
 179                         i = read(fd, cp, n);
 180                         if (i <= 0) {
 181                                 if (lose_counter++ > 16)
 182                                         break;
 183                                 continue;
 184                         }
 185                         n -= i;
 186                         cp += i;
 187                         lose_counter = 0;
 188                 }
 189         }
 190
 191         /*
 192          * We do this all the time, but this is the only source of
 193          * randomness if /dev/random/urandom is out to lunch.
 194          */
 195         for (cp = buf, i = 0; i < nbytes; i++)
 196                 *cp++ ^= (rand() >> 7) & 0xFF;
 197 #ifdef DO_JRAND_MIX
 198         memcpy(tmp_seed, jrand_seed, sizeof(tmp_seed));
 199         jrand_seed[2] = jrand_seed[2] ^ syscall(__NR_gettid);
 200         for (cp = buf, i = 0; i < nbytes; i++)
 201                 *cp++ ^= (jrand48(tmp_seed) >> 7) & 0xFF;
 202         memcpy(jrand_seed, tmp_seed,
 203                sizeof(jrand_seed)-sizeof(unsigned short));
 204 #endif
 205
 206         return;
 207 }
 208
 209 /*
 210  * Get the ethernet hardware address, if we can find it...
 211  *
 212  * XXX for a windows version, probably should use GetAdaptersInfo:
 213  * http://www.codeguru.com/cpp/i-n/network/networkinformation/article.php/c5451
 214  * commenting out get_node_id just to get gen_uuid to compile under windows
 215  * is not the right way to go!
 216  */
 217 static int get_node_id(unsigned char *node_id)
 218 {
 219 #ifdef HAVE_NET_IF_H
 220         int             sd;
 221         struct ifreq    ifr, *ifrp;
 222         struct ifconf   ifc;
 223         char buf[1024];
 224         int             n, i;
 225         unsigned char   *a;
 226 #ifdef HAVE_NET_IF_DL_H
 227         struct sockaddr_dl *sdlp;
 228 #endif
 229
 230 /*
 231  * BSD 4.4 defines the size of an ifreq to be
 232  * max(sizeof(ifreq), sizeof(ifreq.ifr_name)+ifreq.ifr_addr.sa_len
 233  * However, under earlier systems, sa_len isn't present, so the size is
 234  * just sizeof(struct ifreq)
 235  */
 236 #ifdef HAVE_SA_LEN
 237 #ifndef max
 238 #define max(a,b) ((a) > (b) ? (a) : (b))
 239 #endif
 240 #define ifreq_size(i) max(sizeof(struct ifreq),\
 241      sizeof((i).ifr_name)+(i).ifr_addr.sa_len)
 242 #else
 243 #define ifreq_size(i) sizeof(struct ifreq)
 244 #endif /* HAVE_SA_LEN*/
 245
 246         sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
 247         if (sd < 0) {
 248                 return -1;
 249         }
 250         memset(buf, 0, sizeof(buf));
 251         ifc.ifc_len = sizeof(buf);
 252         ifc.ifc_buf = buf;
 253         if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) {
 254                 close(sd);
 255                 return -1;
 256         }
 257         n = ifc.ifc_len;
 258         for (i = 0; i < n; i+= ifreq_size(*ifrp) ) {
 259                 ifrp = (struct ifreq *)((char *) ifc.ifc_buf+i);
 260                 strncpy(ifr.ifr_name, ifrp->ifr_name, IFNAMSIZ);
 261 #ifdef SIOCGIFHWADDR
 262                 if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)
 263                         continue;
 264                 a = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
 265 #else
 266 #ifdef SIOCGENADDR
 267                 if (ioctl(sd, SIOCGENADDR, &ifr) < 0)
 268                         continue;
 269                 a = (unsigned char *) ifr.ifr_enaddr;
 270 #else
 271 #ifdef HAVE_NET_IF_DL_H
 272                 sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr;
 273                 if ((sdlp->sdl_family != AF_LINK) || (sdlp->sdl_alen != 6))
 274                         continue;
 275                 a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen];
 276 #else
 277                 /*
 278                  * XXX we don't have a way of getting the hardware
 279                  * address
 280                  */
 281                 close(sd);
 282                 return 0;
 283 #endif /* HAVE_NET_IF_DL_H */
 284 #endif /* SIOCGENADDR */
 285 #endif /* SIOCGIFHWADDR */
 286                 if (!a[0] && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
 287                         continue;
 288                 if (node_id) {
 289                         memcpy(node_id, a, 6);
 290                         close(sd);
 291                         return 1;
 292                 }
 293         }
 294         close(sd);
 295 #endif
 296         return 0;
 297 }
 298
 299 /* Assume that the gettimeofday() has microsecond granularity */
 300 #define MAX_ADJUSTMENT 10
 301
 302 static int get_clock(uint32_t *clock_high, uint32_t *clock_low,
 303                      uint16_t *ret_clock_seq, int *num)
 304 {
 305         THREAD_LOCAL int                adjustment = 0;
 306         THREAD_LOCAL struct timeval     last = {0, 0};
 307         THREAD_LOCAL int                state_fd = -2;
 308         THREAD_LOCAL FILE               *state_f;
 309         THREAD_LOCAL uint16_t           clock_seq;
 310         struct timeval                  tv;
 311         struct flock                    fl;
 312         uint64_t                        clock_reg;
 313         mode_t                          save_umask;
 314
 315         if (state_fd == -2) {
 316                 save_umask = umask(0);
 317                 state_fd = open("/var/lib/libuuid/clock.txt",
 318                                 O_RDWR|O_CREAT, 0660);
 319                 (void) umask(save_umask);
 320                 state_f = fdopen(state_fd, "r+");
 321                 if (!state_f) {
 322                         close(state_fd);
 323                         state_fd = -1;
 324                 }
 325         }
 326         fl.l_type = F_WRLCK;
 327         fl.l_whence = SEEK_SET;
 328         fl.l_start = 0;
 329         fl.l_len = 0;
 330         fl.l_pid = 0;
 331         if (state_fd >= 0) {
 332                 rewind(state_f);
 333                 while (fcntl(state_fd, F_SETLKW, &fl) < 0) {
 334                         if ((errno == EAGAIN) || (errno == EINTR))
 335                                 continue;
 336                         fclose(state_f);
 337                         close(state_fd);
 338                         state_fd = -1;
 339                         break;
 340                 }
 341         }
 342         if (state_fd >= 0) {
 343                 unsigned int cl;
 344                 unsigned long tv1, tv2;
 345                 int a;
 346
 347                 if (fscanf(state_f, "clock: %04x tv: %lu %lu adj: %d\n",
 348                            &cl, &tv1, &tv2, &a) == 4) {
 349                         clock_seq = cl & 0x3FFF;
 350                         last.tv_sec = tv1;
 351                         last.tv_usec = tv2;
 352                         adjustment = a;
 353                 }
 354         }
 355
 356         if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
 357                 get_random_bytes(&clock_seq, sizeof(clock_seq));
 358                 clock_seq &= 0x3FFF;
 359                 gettimeofday(&last, 0);
 360                 last.tv_sec--;
 361         }
 362
 363 try_again:
 364         gettimeofday(&tv, 0);
 365         if ((tv.tv_sec < last.tv_sec) ||
 366             ((tv.tv_sec == last.tv_sec) &&
 367              (tv.tv_usec < last.tv_usec))) {
 368                 clock_seq = (clock_seq+1) & 0x3FFF;
 369                 adjustment = 0;
 370                 last = tv;
 371         } else if ((tv.tv_sec == last.tv_sec) &&
 372             (tv.tv_usec == last.tv_usec)) {
 373                 if (adjustment >= MAX_ADJUSTMENT)
 374                         goto try_again;
 375                 adjustment++;
 376         } else {
 377                 adjustment = 0;
 378                 last = tv;
 379         }
 380
 381         clock_reg = tv.tv_usec*10 + adjustment;
 382         clock_reg += ((uint64_t) tv.tv_sec)*10000000;
 383         clock_reg += (((uint64_t) 0x01B21DD2) << 32) + 0x13814000;
 384
 385         if (num && (*num > 1)) {
 386                 adjustment += *num - 1;
 387                 last.tv_usec += adjustment / 10;
 388                 adjustment = adjustment % 10;
 389                 last.tv_sec += last.tv_usec / 1000000;
 390                 last.tv_usec = last.tv_usec % 1000000;
 391         }
 392
 393         if (state_fd > 0) {
 394                 rewind(state_f);
 395                 ftruncate(state_fd, 0);
 396                 fprintf(state_f, "clock: %04x tv: %lu %lu adj: %d\n",
 397                         clock_seq, last.tv_sec, last.tv_usec, adjustment);
 398                 fflush(state_f);
 399                 rewind(state_f);
 400                 fl.l_type = F_UNLCK;
 401                 fcntl(state_fd, F_SETLK, &fl);
 402         }
 403
 404         *clock_high = clock_reg >> 32;
 405         *clock_low = clock_reg;
 406         *ret_clock_seq = clock_seq;
 407         return 0;
 408 }
 409
 410 static ssize_t read_all(int fd, char *buf, size_t count)
 411 {
 412         ssize_t ret;
 413         ssize_t c = 0;
 414
 415         memset(buf, 0, count);
 416         while (count > 0) {
 417                 ret = read(fd, buf, count);
 418                 if (ret < 0) {
 419                         if ((errno == EAGAIN) || (errno == EINTR))
 420                                 continue;
 421                         return -1;
 422                 }
 423                 count -= ret;
 424                 buf += ret;
 425                 c += ret;
 426         }
 427         return c;
 428 }
 429
 430
 431 /*
 432  * Try using the uuidd daemon to generate the UUID
 433  *
 434  * Returns 0 on success, non-zero on failure.
 435  */
 436 static int get_uuid_via_daemon(int op, uuid_t out, int *num)
 437 {
 438 #if defined(USE_UUIDD) && defined(HAVE_SYS_UN_H)
 439         char op_buf[64];
 440         int op_len;
 441         int s;
 442         ssize_t ret;
 443         int32_t reply_len = 0, expected = 16;
 444         struct sockaddr_un srv_addr;
 445         pid_t pid;
 446         static const char *uuidd_path = UUIDD_PATH;
 447         static int access_ret = -2;
 448         static int start_attempts = 0;
 449
 450         if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
 451                 return -1;
 452
 453         srv_addr.sun_family = AF_UNIX;
 454         strcpy(srv_addr.sun_path, UUIDD_SOCKET_PATH);
 455
 456         if (connect(s, (const struct sockaddr *) &srv_addr,
 457                     sizeof(struct sockaddr_un)) < 0) {
 458                 if (access_ret == -2)
 459                         access_ret = access(uuidd_path, X_OK);
 460                 if (access_ret == 0 && start_attempts++ < 5) {
 461                         if ((pid = fork()) == 0) {
 462                                 execl(uuidd_path, "uuidd", "-qT", "300",
 463                                       (char *) NULL);
 464                                 exit(1);
 465                         }
 466                         (void) waitpid(pid, 0, 0);
 467                         if (connect(s, (const struct sockaddr *) &srv_addr,
 468                                     sizeof(struct sockaddr_un)) < 0)
 469                                 goto fail;
 470                 } else
 471                         goto fail;
 472         }
 473         op_buf[0] = op;
 474         op_len = 1;
 475         if (op == UUIDD_OP_BULK_TIME_UUID) {
 476                 memcpy(op_buf+1, num, sizeof(*num));
 477                 op_len += sizeof(*num);
 478                 expected += sizeof(*num);
 479         }
 480
 481         ret = write(s, op_buf, op_len);
 482         if (ret < 1)
 483                 goto fail;
 484
 485         ret = read_all(s, (char *) &reply_len, sizeof(reply_len));
 486         if (ret < 0)
 487                 goto fail;
 488
 489         if (reply_len != expected)
 490                 goto fail;
 491
 492         ret = read_all(s, op_buf, reply_len);
 493
 494         if (op == UUIDD_OP_BULK_TIME_UUID)
 495                 memcpy(op_buf+16, num, sizeof(int));
 496
 497         memcpy(out, op_buf, 16);
 498
 499         close(s);
 500         return ((ret == expected) ? 0 : -1);
 501
 502 fail:
 503         close(s);
 504 #endif
 505         return -1;
 506 }
 507
 508 void uuid__generate_time(uuid_t out, int *num)
 509 {
 510         static unsigned char node_id[6];
 511         static int has_init = 0;
 512         struct uuid uu;
 513         uint32_t        clock_mid;
 514
 515         if (!has_init) {
 516                 if (get_node_id(node_id) <= 0) {
 517                         get_random_bytes(node_id, 6);
 518                         /*
 519                          * Set multicast bit, to prevent conflicts
 520                          * with IEEE 802 addresses obtained from
 521                          * network cards
 522                          */
 523                         node_id[0] |= 0x01;
 524                 }
 525                 has_init = 1;
 526         }
 527         get_clock(&clock_mid, &uu.time_low, &uu.clock_seq, num);
 528         uu.clock_seq |= 0x8000;
 529         uu.time_mid = (uint16_t) clock_mid;
 530         uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) | 0x1000;
 531         memcpy(uu.node, node_id, 6);
 532         uuid_pack(&uu, out);
 533 }
 534
 535 void uuid_generate_time(uuid_t out)
 536 {
 537 #ifdef TLS
 538         THREAD_LOCAL int                num = 0;
 539         THREAD_LOCAL struct uuid        uu;
 540         THREAD_LOCAL time_t             last_time = 0;
 541         time_t                          now;
 542
 543         if (num > 0) {
 544                 now = time(0);
 545                 if (now > last_time+1)
 546                         num = 0;
 547         }
 548         if (num <= 0) {
 549                 num = 1000;
 550                 if (get_uuid_via_daemon(UUIDD_OP_BULK_TIME_UUID,
 551                                         out, &num) == 0) {
 552                         last_time = time(0);
 553                         uuid_unpack(out, &uu);
 554                         num--;
 555                         return;
 556                 }
 557                 num = 0;
 558         }
 559         if (num > 0) {
 560                 uu.time_low++;
 561                 if (uu.time_low == 0) {
 562                         uu.time_mid++;
 563                         if (uu.time_mid == 0)
 564                                 uu.time_hi_and_version++;
 565                 }
 566                 num--;
 567                 uuid_pack(&uu, out);
 568                 return;
 569         }
 570 #else
 571         if (get_uuid_via_daemon(UUIDD_OP_TIME_UUID, out, 0) == 0)
 572                 return;
 573 #endif
 574
 575         uuid__generate_time(out, 0);
 576 }
 577
 578
 579 void uuid__generate_random(uuid_t out, int *num)
 580 {
 581         uuid_t  buf;
 582         struct uuid uu;
 583         int i, n;
 584
 585         if (!num || !*num)
 586                 n = 1;
 587         else
 588                 n = *num;
 589
 590         for (i = 0; i < n; i++) {
 591                 get_random_bytes(buf, sizeof(buf));
 592                 uuid_unpack(buf, &uu);
 593
 594                 uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
 595                 uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF)
 596                         | 0x4000;
 597                 uuid_pack(&uu, out);
 598                 out += sizeof(uuid_t);
 599         }
 600 }
 601
 602 void uuid_generate_random(uuid_t out)
 603 {
 604         int     num = 1;
 605         /* No real reason to use the daemon for random uuid's -- yet */
 606
 607         uuid__generate_random(out, &num);
 608 }
 609
 610
 611 /*
 612  * This is the generic front-end to uuid_generate_random and
 613  * uuid_generate_time.  It uses uuid_generate_random only if
 614  * /dev/urandom is available, since otherwise we won't have
 615  * high-quality randomness.
 616  */
 617 void uuid_generate(uuid_t out)
 618 {
 619         if (get_random_fd() >= 0)
 620                 uuid_generate_random(out);
 621         else
 622                 uuid_generate_time(out);
 623 }