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 #define _DEFAULT_SOURCE   /* since glibc 2.20 _SVID_SOURCE is deprecated */
  41
  42 #include "config.h"
  43
  44 #ifdef _WIN32
  45 #define _WIN32_WINNT 0x0500
  46 #include <windows.h>
  47 #define UUID MYUUID
  48 #endif
  49 #include <stdio.h>
  50 #ifdef HAVE_UNISTD_H
  51 #include <unistd.h>
  52 #endif
  53 #ifdef HAVE_STDLIB_H
  54 #include <stdlib.h>
  55 #endif
  56 #include <string.h>
  57 #include <fcntl.h>
  58 #include <errno.h>
  59 #include <sys/types.h>
  60 #ifdef HAVE_SYS_TIME_H
  61 #include <sys/time.h>
  62 #endif
  63 #ifdef HAVE_SYS_WAIT_H
  64 #include <sys/wait.h>
  65 #endif
  66 #include <sys/stat.h>
  67 #ifdef HAVE_SYS_FILE_H
  68 #include <sys/file.h>
  69 #endif
  70 #ifdef HAVE_SYS_IOCTL_H
  71 #include <sys/ioctl.h>
  72 #endif
  73 #ifdef HAVE_SYS_SOCKET_H
  74 #include <sys/socket.h>
  75 #endif
  76 #ifdef HAVE_SYS_UN_H
  77 #include <sys/un.h>
  78 #endif
  79 #ifdef HAVE_SYS_SOCKIO_H
  80 #include <sys/sockio.h>
  81 #endif
  82 #ifdef HAVE_NET_IF_H
  83 #include <net/if.h>
  84 #endif
  85 #ifdef HAVE_NETINET_IN_H
  86 #include <netinet/in.h>
  87 #endif
  88 #ifdef HAVE_NET_IF_DL_H
  89 #include <net/if_dl.h>
  90 #endif
  91 #if defined(__linux__) && defined(HAVE_SYS_SYSCALL_H)
  92 #include <sys/syscall.h>
  93 #endif
  94 #ifdef HAVE_SYS_RESOURCE_H
  95 #include <sys/resource.h>
  96 #endif
  97
  98 #include "uuidP.h"
  99 #include "uuidd.h"
 100
 101 #ifdef HAVE_SRANDOM
 102 #define srand(x)        srandom(x)
 103 #define rand()          random()
 104 #endif
 105
 106 #ifdef TLS
 107 #define THREAD_LOCAL static TLS
 108 #else
 109 #define THREAD_LOCAL static
 110 #endif
 111
 112 #if defined(__linux__) && defined(__NR_gettid) && defined(HAVE_JRAND48)
 113 #define DO_JRAND_MIX
 114 THREAD_LOCAL unsigned short jrand_seed[3];
 115 #endif
 116
 117 #ifdef _WIN32
 118 #ifndef USE_MINGW
 119 static void gettimeofday (struct timeval *tv, void *dummy)
 120 {
 121         FILETIME        ftime;
 122         uint64_t        n;
 123
 124         GetSystemTimeAsFileTime (&ftime);
 125         n = (((uint64_t) ftime.dwHighDateTime << 32)
 126              + (uint64_t) ftime.dwLowDateTime);
 127         if (n) {
 128                 n /= 10;
 129                 n -= ((369 * 365 + 89) * (uint64_t) 86400) * 1000000;
 130         }
 131
 132         tv->tv_sec = n / 1000000;
 133         tv->tv_usec = n % 1000000;
 134 }
 135 #endif
 136 #endif
 137
 138 static int get_random_fd(void)
 139 {
 140         struct timeval  tv;
 141         static int      fd = -2;
 142         int             i;
 143
 144         if (fd == -2) {
 145                 gettimeofday(&tv, 0);
 146 #ifndef _WIN32
 147                 fd = open("/dev/urandom", O_RDONLY);
 148                 if (fd == -1)
 149                         fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
 150                 if (fd >= 0) {
 151                         i = fcntl(fd, F_GETFD);
 152                         if (i >= 0)
 153                                 fcntl(fd, F_SETFD, i | FD_CLOEXEC);
 154                 }
 155 #endif
 156                 srand(((unsigned)getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
 157 #ifdef DO_JRAND_MIX
 158                 jrand_seed[0] = getpid() ^ (tv.tv_sec & 0xFFFF);
 159                 jrand_seed[1] = getppid() ^ (tv.tv_usec & 0xFFFF);
 160                 jrand_seed[2] = (tv.tv_sec ^ tv.tv_usec) >> 16;
 161 #endif
 162         }
 163         /* Crank the random number generator a few times */
 164         gettimeofday(&tv, 0);
 165         for (i = (tv.tv_sec ^ tv.tv_usec) & 0x1F; i > 0; i--)
 166                 rand();
 167         return fd;
 168 }
 169
 170
 171 /*
 172  * Generate a series of random bytes.  Use /dev/urandom if possible,
 173  * and if not, use srandom/random.
 174  */
 175 static void get_random_bytes(void *buf, int nbytes)
 176 {
 177         int i, n = nbytes, fd = get_random_fd();
 178         int lose_counter = 0;
 179         unsigned char *cp = buf;
 180
 181         if (fd >= 0) {
 182                 while (n > 0) {
 183                         i = read(fd, cp, n);
 184                         if (i <= 0) {
 185                                 if (lose_counter++ > 16)
 186                                         break;
 187                                 continue;
 188                         }
 189                         n -= i;
 190                         cp += i;
 191                         lose_counter = 0;
 192                 }
 193         }
 194
 195         /*
 196          * We do this all the time, but this is the only source of
 197          * randomness if /dev/random/urandom is out to lunch.
 198          */
 199         for (cp = buf, i = 0; i < nbytes; i++)
 200                 *cp++ ^= (rand() >> 7) & 0xFF;
 201 #ifdef DO_JRAND_MIX
 202         {
 203                 unsigned short tmp_seed[3];
 204
 205                 memcpy(tmp_seed, jrand_seed, sizeof(tmp_seed));
 206                 jrand_seed[2] = jrand_seed[2] ^ syscall(__NR_gettid);
 207                 for (cp = buf, i = 0; i < nbytes; i++)
 208                         *cp++ ^= (jrand48(tmp_seed) >> 7) & 0xFF;
 209                 memcpy(jrand_seed, tmp_seed,
 210                        sizeof(jrand_seed) - sizeof(unsigned short));
 211         }
 212 #endif
 213
 214         return;
 215 }
 216
 217 /*
 218  * Get the ethernet hardware address, if we can find it...
 219  *
 220  * XXX for a windows version, probably should use GetAdaptersInfo:
 221  * http://www.codeguru.com/cpp/i-n/network/networkinformation/article.php/c5451
 222  * commenting out get_node_id just to get gen_uuid to compile under windows
 223  * is not the right way to go!
 224  */
 225 static int get_node_id(unsigned char *node_id)
 226 {
 227 #ifdef HAVE_NET_IF_H
 228         int             sd;
 229         struct ifreq    ifr, *ifrp;
 230         struct ifconf   ifc;
 231         char buf[1024];
 232         int             n, i;
 233         unsigned char   *a;
 234 #ifdef HAVE_NET_IF_DL_H
 235         struct sockaddr_dl *sdlp;
 236 #endif
 237
 238 /*
 239  * BSD 4.4 defines the size of an ifreq to be
 240  * max(sizeof(ifreq), sizeof(ifreq.ifr_name)+ifreq.ifr_addr.sa_len
 241  * However, under earlier systems, sa_len isn't present, so the size is
 242  * just sizeof(struct ifreq)
 243  */
 244 #ifdef HAVE_SA_LEN
 245 #ifndef max
 246 #define max(a,b) ((a) > (b) ? (a) : (b))
 247 #endif
 248 #define ifreq_size(i) max(sizeof(struct ifreq),\
 249      sizeof((i).ifr_name)+(i).ifr_addr.sa_len)
 250 #else
 251 #define ifreq_size(i) sizeof(struct ifreq)
 252 #endif /* HAVE_SA_LEN*/
 253
 254         sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
 255         if (sd < 0) {
 256                 return -1;
 257         }
 258         memset(buf, 0, sizeof(buf));
 259         ifc.ifc_len = sizeof(buf);
 260         ifc.ifc_buf = buf;
 261         if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) {
 262                 close(sd);
 263                 return -1;
 264         }
 265         n = ifc.ifc_len;
 266         for (i = 0; i < n; i+= ifreq_size(*ifrp) ) {
 267                 ifrp = (struct ifreq *)((char *) ifc.ifc_buf+i);
 268                 strncpy(ifr.ifr_name, ifrp->ifr_name, IFNAMSIZ);
 269 #ifdef SIOCGIFHWADDR
 270                 if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)
 271                         continue;
 272                 a = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
 273 #else
 274 #ifdef SIOCGENADDR
 275                 if (ioctl(sd, SIOCGENADDR, &ifr) < 0)
 276                         continue;
 277                 a = (unsigned char *) ifr.ifr_enaddr;
 278 #else
 279 #ifdef HAVE_NET_IF_DL_H
 280                 sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr;
 281                 if ((sdlp->sdl_family != AF_LINK) || (sdlp->sdl_alen != 6))
 282                         continue;
 283                 a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen];
 284 #else
 285                 /*
 286                  * XXX we don't have a way of getting the hardware
 287                  * address
 288                  */
 289                 close(sd);
 290                 return 0;
 291 #endif /* HAVE_NET_IF_DL_H */
 292 #endif /* SIOCGENADDR */
 293 #endif /* SIOCGIFHWADDR */
 294                 if (!a[0] && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
 295                         continue;
 296                 if (node_id) {
 297                         memcpy(node_id, a, 6);
 298                         close(sd);
 299                         return 1;
 300                 }
 301         }
 302         close(sd);
 303 #endif
 304         return 0;
 305 }
 306
 307 /* Assume that the gettimeofday() has microsecond granularity */
 308 #define MAX_ADJUSTMENT 10
 309
 310 static int get_clock(uint32_t *clock_high, uint32_t *clock_low,
 311                      uint16_t *ret_clock_seq, int *num)
 312 {
 313         THREAD_LOCAL int                adjustment = 0;
 314         THREAD_LOCAL struct timeval     last = {0, 0};
 315         THREAD_LOCAL int                state_fd = -2;
 316         THREAD_LOCAL FILE               *state_f;
 317         THREAD_LOCAL uint16_t           clock_seq;
 318         struct timeval                  tv;
 319 #ifndef _WIN32
 320         struct flock                    fl;
 321 #endif
 322         uint64_t                        clock_reg;
 323         mode_t                          save_umask;
 324         int                             len;
 325
 326         if (state_fd == -2) {
 327                 save_umask = umask(0);
 328                 state_fd = open("/var/lib/libuuid/clock.txt",
 329                                 O_RDWR|O_CREAT, 0660);
 330                 (void) umask(save_umask);
 331                 if (state_fd >= 0) {
 332                         state_f = fdopen(state_fd, "r+");
 333                         if (!state_f) {
 334                                 close(state_fd);
 335                                 state_fd = -1;
 336                         }
 337                 }
 338         }
 339 #ifndef _WIN32
 340         fl.l_type = F_WRLCK;
 341         fl.l_whence = SEEK_SET;
 342         fl.l_start = 0;
 343         fl.l_len = 0;
 344         fl.l_pid = 0;
 345         if (state_fd >= 0) {
 346                 rewind(state_f);
 347                 while (fcntl(state_fd, F_SETLKW, &fl) < 0) {
 348                         if ((errno == EAGAIN) || (errno == EINTR))
 349                                 continue;
 350                         fclose(state_f);
 351                         state_fd = -1;
 352                         break;
 353                 }
 354         }
 355 #endif
 356         if (state_fd >= 0) {
 357                 unsigned int cl;
 358                 unsigned long tv1, tv2;
 359                 int a;
 360
 361                 if (fscanf(state_f, "clock: %04x tv: %lu %lu adj: %d\n",
 362                            &cl, &tv1, &tv2, &a) == 4) {
 363                         clock_seq = cl & 0x3FFF;
 364                         last.tv_sec = tv1;
 365                         last.tv_usec = tv2;
 366                         adjustment = a;
 367                 }
 368         }
 369
 370         if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
 371                 get_random_bytes(&clock_seq, sizeof(clock_seq));
 372                 clock_seq &= 0x3FFF;
 373                 gettimeofday(&last, 0);
 374                 last.tv_sec--;
 375         }
 376
 377 try_again:
 378         gettimeofday(&tv, 0);
 379         if ((tv.tv_sec < last.tv_sec) ||
 380             ((tv.tv_sec == last.tv_sec) &&
 381              (tv.tv_usec < last.tv_usec))) {
 382                 clock_seq = (clock_seq+1) & 0x3FFF;
 383                 adjustment = 0;
 384                 last = tv;
 385         } else if ((tv.tv_sec == last.tv_sec) &&
 386             (tv.tv_usec == last.tv_usec)) {
 387                 if (adjustment >= MAX_ADJUSTMENT)
 388                         goto try_again;
 389                 adjustment++;
 390         } else {
 391                 adjustment = 0;
 392                 last = tv;
 393         }
 394
 395         clock_reg = tv.tv_usec*10 + adjustment;
 396         clock_reg += ((uint64_t) tv.tv_sec)*10000000;
 397         clock_reg += (((uint64_t) 0x01B21DD2) << 32) + 0x13814000;
 398
 399         if (num && (*num > 1)) {
 400                 adjustment += *num - 1;
 401                 last.tv_usec += adjustment / 10;
 402                 adjustment = adjustment % 10;
 403                 last.tv_sec += last.tv_usec / 1000000;
 404                 last.tv_usec = last.tv_usec % 1000000;
 405         }
 406
 407         if (state_fd > 0) {
 408                 rewind(state_f);
 409                 len = fprintf(state_f,
 410                               "clock: %04x tv: %016lu %08lu adj: %08d\n",
 411                               clock_seq, last.tv_sec, (long)last.tv_usec,
 412                               adjustment);
 413                 fflush(state_f);
 414                 if (ftruncate(state_fd, len) < 0) {
 415                         fprintf(state_f, "                   \n");
 416                         fflush(state_f);
 417                 }
 418                 rewind(state_f);
 419 #ifndef _WIN32
 420                 fl.l_type = F_UNLCK;
 421                 if (fcntl(state_fd, F_SETLK, &fl) < 0) {
 422                         fclose(state_f);
 423                         state_fd = -1;
 424                 }
 425 #endif
 426         }
 427
 428         *clock_high = clock_reg >> 32;
 429         *clock_low = clock_reg;
 430         *ret_clock_seq = clock_seq;
 431         return 0;
 432 }
 433
 434 #if defined(USE_UUIDD) && defined(HAVE_SYS_UN_H)
 435 static ssize_t read_all(int fd, char *buf, size_t count)
 436 {
 437         ssize_t ret;
 438         ssize_t c = 0;
 439         int tries = 0;
 440
 441         memset(buf, 0, count);
 442         while (count > 0) {
 443                 ret = read(fd, buf, count);
 444                 if (ret <= 0) {
 445                         if ((errno == EAGAIN || errno == EINTR || ret == 0) &&
 446                             (tries++ < 5))
 447                                 continue;
 448                         return c ? c : -1;
 449                 }
 450                 if (ret > 0)
 451                         tries = 0;
 452                 count -= ret;
 453                 buf += ret;
 454                 c += ret;
 455         }
 456         return c;
 457 }
 458
 459 /*
 460  * Close all file descriptors
 461  */
 462 static void close_all_fds(void)
 463 {
 464         int i, max;
 465
 466 #if defined(HAVE_SYSCONF) && defined(_SC_OPEN_MAX)
 467         max = sysconf(_SC_OPEN_MAX);
 468 #elif defined(HAVE_GETDTABLESIZE)
 469         max = getdtablesize();
 470 #elif defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
 471         struct rlimit rl;
 472
 473         getrlimit(RLIMIT_NOFILE, &rl);
 474         max = rl.rlim_cur;
 475 #else
 476         max = OPEN_MAX;
 477 #endif
 478
 479         for (i=0; i < max; i++) {
 480                 close(i);
 481                 if (i <= 2)
 482                         open("/dev/null", O_RDWR);
 483         }
 484 }
 485 #endif /* defined(USE_UUIDD) && defined(HAVE_SYS_UN_H) */
 486
 487 #if __GNUC_PREREQ (4, 6)
 488 #pragma GCC diagnostic push
 489 #if !defined(USE_UUIDD) || !defined(HAVE_SYS_UN_H)
 490 #pragma GCC diagnostic ignored "-Wunused-parameter"
 491 #endif
 492 #endif
 493 /*
 494  * Try using the uuidd daemon to generate the UUID
 495  *
 496  * Returns 0 on success, non-zero on failure.
 497  */
 498 static int get_uuid_via_daemon(int op, uuid_t out, int *num)
 499 {
 500 #if defined(USE_UUIDD) && defined(HAVE_SYS_UN_H)
 501         char op_buf[64];
 502         int op_len;
 503         int s;
 504         ssize_t ret;
 505         int32_t reply_len = 0, expected = 16;
 506         struct sockaddr_un srv_addr;
 507         struct stat st;
 508         pid_t pid;
 509         static const char *uuidd_path = UUIDD_PATH;
 510         static int access_ret = -2;
 511         static int start_attempts = 0;
 512
 513         if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
 514                 return -1;
 515
 516         srv_addr.sun_family = AF_UNIX;
 517         strcpy(srv_addr.sun_path, UUIDD_SOCKET_PATH);
 518
 519         if (connect(s, (const struct sockaddr *) &srv_addr,
 520                     sizeof(struct sockaddr_un)) < 0) {
 521                 if (access_ret == -2)
 522                         access_ret = access(uuidd_path, X_OK);
 523                 if (access_ret == 0)
 524                         access_ret = stat(uuidd_path, &st);
 525                 if (access_ret == 0 && (st.st_mode & (S_ISUID | S_ISGID)) == 0)
 526                         access_ret = access(UUIDD_DIR, W_OK);
 527                 if (access_ret == 0 && start_attempts++ < 5) {
 528                         if ((pid = fork()) == 0) {
 529                                 close_all_fds();
 530                                 execl(uuidd_path, "uuidd", "-qT", "300",
 531                                       (char *) NULL);
 532                                 exit(1);
 533                         }
 534                         (void) waitpid(pid, 0, 0);
 535                         if (connect(s, (const struct sockaddr *) &srv_addr,
 536                                     sizeof(struct sockaddr_un)) < 0)
 537                                 goto fail;
 538                 } else
 539                         goto fail;
 540         }
 541         op_buf[0] = op;
 542         op_len = 1;
 543         if (op == UUIDD_OP_BULK_TIME_UUID) {
 544                 memcpy(op_buf+1, num, sizeof(*num));
 545                 op_len += sizeof(*num);
 546                 expected += sizeof(*num);
 547         }
 548
 549         ret = write(s, op_buf, op_len);
 550         if (ret < 1)
 551                 goto fail;
 552
 553         ret = read_all(s, (char *) &reply_len, sizeof(reply_len));
 554         if (ret < 0)
 555                 goto fail;
 556
 557         if (reply_len != expected)
 558                 goto fail;
 559
 560         ret = read_all(s, op_buf, reply_len);
 561
 562         if (op == UUIDD_OP_BULK_TIME_UUID)
 563                 memcpy(op_buf+16, num, sizeof(int));
 564
 565         memcpy(out, op_buf, 16);
 566
 567         close(s);
 568         return ((ret == expected) ? 0 : -1);
 569
 570 fail:
 571         close(s);
 572 #endif
 573         return -1;
 574 }
 575 #if __GNUC_PREREQ (4, 6)
 576 #pragma GCC diagnostic pop
 577 #endif
 578
 579 void uuid__generate_time(uuid_t out, int *num)
 580 {
 581         static unsigned char node_id[6];
 582         static int has_init = 0;
 583         struct uuid uu;
 584         uint32_t        clock_mid;
 585
 586         if (!has_init) {
 587                 if (get_node_id(node_id) <= 0) {
 588                         get_random_bytes(node_id, 6);
 589                         /*
 590                          * Set multicast bit, to prevent conflicts
 591                          * with IEEE 802 addresses obtained from
 592                          * network cards
 593                          */
 594                         node_id[0] |= 0x01;
 595                 }
 596                 has_init = 1;
 597         }
 598         get_clock(&clock_mid, &uu.time_low, &uu.clock_seq, num);
 599         uu.clock_seq |= 0x8000;
 600         uu.time_mid = (uint16_t) clock_mid;
 601         uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) | 0x1000;
 602         memcpy(uu.node, node_id, 6);
 603         uuid_pack(&uu, out);
 604 }
 605
 606 void uuid_generate_time(uuid_t out)
 607 {
 608 #ifdef TLS
 609         THREAD_LOCAL int                num = 0;
 610         THREAD_LOCAL struct uuid        uu;
 611         THREAD_LOCAL time_t             last_time = 0;
 612         time_t                          now;
 613
 614         if (num > 0) {
 615                 now = time(0);
 616                 if (now > last_time+1)
 617                         num = 0;
 618         }
 619         if (num <= 0) {
 620                 num = 1000;
 621                 if (get_uuid_via_daemon(UUIDD_OP_BULK_TIME_UUID,
 622                                         out, &num) == 0) {
 623                         last_time = time(0);
 624                         uuid_unpack(out, &uu);
 625                         num--;
 626                         return;
 627                 }
 628                 num = 0;
 629         }
 630         if (num > 0) {
 631                 uu.time_low++;
 632                 if (uu.time_low == 0) {
 633                         uu.time_mid++;
 634                         if (uu.time_mid == 0)
 635                                 uu.time_hi_and_version++;
 636                 }
 637                 num--;
 638                 uuid_pack(&uu, out);
 639                 return;
 640         }
 641 #else
 642         if (get_uuid_via_daemon(UUIDD_OP_TIME_UUID, out, 0) == 0)
 643                 return;
 644 #endif
 645
 646         uuid__generate_time(out, 0);
 647 }
 648
 649
 650 void uuid__generate_random(uuid_t out, int *num)
 651 {
 652         uuid_t  buf;
 653         struct uuid uu;
 654         int i, n;
 655
 656         if (!num || !*num)
 657                 n = 1;
 658         else
 659                 n = *num;
 660
 661         for (i = 0; i < n; i++) {
 662                 get_random_bytes(buf, sizeof(buf));
 663                 uuid_unpack(buf, &uu);
 664
 665                 uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
 666                 uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF)
 667                         | 0x4000;
 668                 uuid_pack(&uu, out);
 669                 out += sizeof(uuid_t);
 670         }
 671 }
 672
 673 void uuid_generate_random(uuid_t out)
 674 {
 675         int     num = 1;
 676         /* No real reason to use the daemon for random uuid's -- yet */
 677
 678         uuid__generate_random(out, &num);
 679 }
 680
 681
 682 /*
 683  * This is the generic front-end to uuid_generate_random and
 684  * uuid_generate_time.  It uses uuid_generate_random only if
 685  * /dev/urandom is available, since otherwise we won't have
 686  * high-quality randomness.
 687  */
 688 void uuid_generate(uuid_t out)
 689 {
 690         if (get_random_fd() >= 0)
 691                 uuid_generate_random(out);
 692         else
 693                 uuid_generate_time(out);
 694 }