qemu-nbd.c

   1 /*
   2  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
   3  *
   4  *  Network Block Device
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; under version 2 of the License.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "qemu-common.h"
  20 #include "block/block.h"
  21 #include "block/nbd.h"
  22 #include "qemu/main-loop.h"
  23 #include "block/snapshot.h"
  24
  25 #include <stdarg.h>
  26 #include <stdio.h>
  27 #include <getopt.h>
  28 #include <err.h>
  29 #include <sys/types.h>
  30 #include <sys/socket.h>
  31 #include <netinet/in.h>
  32 #include <netinet/tcp.h>
  33 #include <arpa/inet.h>
  34 #include <signal.h>
  35 #include <libgen.h>
  36 #include <pthread.h>
  37
  38 #define SOCKET_PATH          "/var/lock/qemu-nbd-%s"
  39 #define QEMU_NBD_OPT_CACHE   1
  40 #define QEMU_NBD_OPT_AIO     2
  41 #define QEMU_NBD_OPT_DISCARD 3
  42
  43 static NBDExport *exp;
  44 static int verbose;
  45 static char *srcpath;
  46 static char *sockpath;
  47 static int persistent = 0;
  48 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
  49 static int shared = 1;
  50 static int nb_fds;
  51
  52 static void usage(const char *name)
  53 {
  54     (printf) (
  55 "Usage: %s [OPTIONS] FILE\n"
  56 "QEMU Disk Network Block Device Server\n"
  57 "\n"
  58 "  -h, --help           display this help and exit\n"
  59 "  -V, --version        output version information and exit\n"
  60 "\n"
  61 "Connection properties:\n"
  62 "  -p, --port=PORT      port to listen on (default `%d')\n"
  63 "  -b, --bind=IFACE     interface to bind to (default `0.0.0.0')\n"
  64 "  -k, --socket=PATH    path to the unix socket\n"
  65 "                       (default '"SOCKET_PATH"')\n"
  66 "  -e, --shared=NUM     device can be shared by NUM clients (default '1')\n"
  67 "  -t, --persistent     don't exit on the last connection\n"
  68 "  -v, --verbose        display extra debugging information\n"
  69 "\n"
  70 "Exposing part of the image:\n"
  71 "  -o, --offset=OFFSET  offset into the image\n"
  72 "  -P, --partition=NUM  only expose partition NUM\n"
  73 "\n"
  74 #ifdef __linux__
  75 "Kernel NBD client support:\n"
  76 "  -c, --connect=DEV    connect FILE to the local NBD device DEV\n"
  77 "  -d, --disconnect     disconnect the specified device\n"
  78 "\n"
  79 #endif
  80 "\n"
  81 "Block device options:\n"
  82 "  -r, --read-only      export read-only\n"
  83 "  -s, --snapshot       use FILE as an external snapshot, create a temporary\n"
  84 "                       file with backing_file=FILE, redirect the write to\n"
  85 "                       the temporary one\n"
  86 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
  87 "                       load an internal snapshot inside FILE and export it\n"
  88 "                       as an read-only device, SNAPSHOT_PARAM format is\n"
  89 "                       'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
  90 "                       '[ID_OR_NAME]'\n"
  91 "  -n, --nocache        disable host cache\n"
  92 "      --cache=MODE     set cache mode (none, writeback, ...)\n"
  93 #ifdef CONFIG_LINUX_AIO
  94 "      --aio=MODE       set AIO mode (native or threads)\n"
  95 #endif
  96 "\n"
  97 "Report bugs to <qemu-devel@nongnu.org>\n"
  98     , name, NBD_DEFAULT_PORT, "DEVICE");
  99 }
 100
 101 static void version(const char *name)
 102 {
 103     printf(
 104 "%s version 0.0.1\n"
 105 "Written by Anthony Liguori.\n"
 106 "\n"
 107 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
 108 "This is free software; see the source for copying conditions.  There is NO\n"
 109 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 110     , name);
 111 }
 112
 113 struct partition_record
 114 {
 115     uint8_t bootable;
 116     uint8_t start_head;
 117     uint32_t start_cylinder;
 118     uint8_t start_sector;
 119     uint8_t system;
 120     uint8_t end_head;
 121     uint8_t end_cylinder;
 122     uint8_t end_sector;
 123     uint32_t start_sector_abs;
 124     uint32_t nb_sectors_abs;
 125 };
 126
 127 static void read_partition(uint8_t *p, struct partition_record *r)
 128 {
 129     r->bootable = p[0];
 130     r->start_head = p[1];
 131     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
 132     r->start_sector = p[2] & 0x3f;
 133     r->system = p[4];
 134     r->end_head = p[5];
 135     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
 136     r->end_sector = p[6] & 0x3f;
 137     r->start_sector_abs = p[8] | p[9] << 8 | p[10] << 16 | p[11] << 24;
 138     r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24;
 139 }
 140
 141 static int find_partition(BlockDriverState *bs, int partition,
 142                           off_t *offset, off_t *size)
 143 {
 144     struct partition_record mbr[4];
 145     uint8_t data[512];
 146     int i;
 147     int ext_partnum = 4;
 148     int ret;
 149
 150     if ((ret = bdrv_read(bs, 0, data, 1)) < 0) {
 151         errno = -ret;
 152         err(EXIT_FAILURE, "error while reading");
 153     }
 154
 155     if (data[510] != 0x55 || data[511] != 0xaa) {
 156         return -EINVAL;
 157     }
 158
 159     for (i = 0; i < 4; i++) {
 160         read_partition(&data[446 + 16 * i], &mbr[i]);
 161
 162         if (!mbr[i].nb_sectors_abs)
 163             continue;
 164
 165         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
 166             struct partition_record ext[4];
 167             uint8_t data1[512];
 168             int j;
 169
 170             if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) {
 171                 errno = -ret;
 172                 err(EXIT_FAILURE, "error while reading");
 173             }
 174
 175             for (j = 0; j < 4; j++) {
 176                 read_partition(&data1[446 + 16 * j], &ext[j]);
 177                 if (!ext[j].nb_sectors_abs)
 178                     continue;
 179
 180                 if ((ext_partnum + j + 1) == partition) {
 181                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
 182                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
 183                     return 0;
 184                 }
 185             }
 186             ext_partnum += 4;
 187         } else if ((i + 1) == partition) {
 188             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
 189             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
 190             return 0;
 191         }
 192     }
 193
 194     return -ENOENT;
 195 }
 196
 197 static void termsig_handler(int signum)
 198 {
 199     state = TERMINATE;
 200     qemu_notify_event();
 201 }
 202
 203 static void *show_parts(void *arg)
 204 {
 205     char *device = arg;
 206     int nbd;
 207
 208     /* linux just needs an open() to trigger
 209      * the partition table update
 210      * but remember to load the module with max_part != 0 :
 211      *     modprobe nbd max_part=63
 212      */
 213     nbd = open(device, O_RDWR);
 214     if (nbd >= 0) {
 215         close(nbd);
 216     }
 217     return NULL;
 218 }
 219
 220 static void *nbd_client_thread(void *arg)
 221 {
 222     char *device = arg;
 223     off_t size;
 224     size_t blocksize;
 225     uint32_t nbdflags;
 226     int fd, sock;
 227     int ret;
 228     pthread_t show_parts_thread;
 229
 230     sock = unix_socket_outgoing(sockpath);
 231     if (sock < 0) {
 232         goto out;
 233     }
 234
 235     ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
 236                                 &size, &blocksize);
 237     if (ret < 0) {
 238         goto out;
 239     }
 240
 241     fd = open(device, O_RDWR);
 242     if (fd < 0) {
 243         /* Linux-only, we can use %m in printf.  */
 244         fprintf(stderr, "Failed to open %s: %m", device);
 245         goto out;
 246     }
 247
 248     ret = nbd_init(fd, sock, nbdflags, size, blocksize);
 249     if (ret < 0) {
 250         goto out;
 251     }
 252
 253     /* update partition table */
 254     pthread_create(&show_parts_thread, NULL, show_parts, device);
 255
 256     if (verbose) {
 257         fprintf(stderr, "NBD device %s is now connected to %s\n",
 258                 device, srcpath);
 259     } else {
 260         /* Close stderr so that the qemu-nbd process exits.  */
 261         dup2(STDOUT_FILENO, STDERR_FILENO);
 262     }
 263
 264     ret = nbd_client(fd);
 265     if (ret) {
 266         goto out;
 267     }
 268     close(fd);
 269     kill(getpid(), SIGTERM);
 270     return (void *) EXIT_SUCCESS;
 271
 272 out:
 273     kill(getpid(), SIGTERM);
 274     return (void *) EXIT_FAILURE;
 275 }
 276
 277 static int nbd_can_accept(void *opaque)
 278 {
 279     return nb_fds < shared;
 280 }
 281
 282 static void nbd_export_closed(NBDExport *exp)
 283 {
 284     assert(state == TERMINATING);
 285     state = TERMINATED;
 286 }
 287
 288 static void nbd_client_closed(NBDClient *client)
 289 {
 290     nb_fds--;
 291     if (nb_fds == 0 && !persistent && state == RUNNING) {
 292         state = TERMINATE;
 293     }
 294     qemu_notify_event();
 295     nbd_client_put(client);
 296 }
 297
 298 static void nbd_accept(void *opaque)
 299 {
 300     int server_fd = (uintptr_t) opaque;
 301     struct sockaddr_in addr;
 302     socklen_t addr_len = sizeof(addr);
 303
 304     int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
 305     if (state >= TERMINATE) {
 306         close(fd);
 307         return;
 308     }
 309
 310     if (fd >= 0 && nbd_client_new(exp, fd, nbd_client_closed)) {
 311         nb_fds++;
 312     }
 313 }
 314
 315 int main(int argc, char **argv)
 316 {
 317     BlockDriverState *bs;
 318     BlockDriver *drv;
 319     off_t dev_offset = 0;
 320     uint32_t nbdflags = 0;
 321     bool disconnect = false;
 322     const char *bindto = "0.0.0.0";
 323     char *device = NULL;
 324     int port = NBD_DEFAULT_PORT;
 325     off_t fd_size;
 326     QemuOpts *sn_opts = NULL;
 327     const char *sn_id_or_name = NULL;
 328     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:";
 329     struct option lopt[] = {
 330         { "help", 0, NULL, 'h' },
 331         { "version", 0, NULL, 'V' },
 332         { "bind", 1, NULL, 'b' },
 333         { "port", 1, NULL, 'p' },
 334         { "socket", 1, NULL, 'k' },
 335         { "offset", 1, NULL, 'o' },
 336         { "read-only", 0, NULL, 'r' },
 337         { "partition", 1, NULL, 'P' },
 338         { "connect", 1, NULL, 'c' },
 339         { "disconnect", 0, NULL, 'd' },
 340         { "snapshot", 0, NULL, 's' },
 341         { "load-snapshot", 1, NULL, 'l' },
 342         { "nocache", 0, NULL, 'n' },
 343         { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
 344 #ifdef CONFIG_LINUX_AIO
 345         { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
 346 #endif
 347         { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
 348         { "shared", 1, NULL, 'e' },
 349         { "format", 1, NULL, 'f' },
 350         { "persistent", 0, NULL, 't' },
 351         { "verbose", 0, NULL, 'v' },
 352         { NULL, 0, NULL, 0 }
 353     };
 354     int ch;
 355     int opt_ind = 0;
 356     int li;
 357     char *end;
 358     int flags = BDRV_O_RDWR;
 359     int partition = -1;
 360     int ret;
 361     int fd;
 362     bool seen_cache = false;
 363     bool seen_discard = false;
 364 #ifdef CONFIG_LINUX_AIO
 365     bool seen_aio = false;
 366 #endif
 367     pthread_t client_thread;
 368     const char *fmt = NULL;
 369     Error *local_err = NULL;
 370
 371     /* The client thread uses SIGTERM to interrupt the server.  A signal
 372      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 373      */
 374     struct sigaction sa_sigterm;
 375     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 376     sa_sigterm.sa_handler = termsig_handler;
 377     sigaction(SIGTERM, &sa_sigterm, NULL);
 378
 379     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 380         switch (ch) {
 381         case 's':
 382             flags |= BDRV_O_SNAPSHOT;
 383             break;
 384         case 'n':
 385             optarg = (char *) "none";
 386             /* fallthrough */
 387         case QEMU_NBD_OPT_CACHE:
 388             if (seen_cache) {
 389                 errx(EXIT_FAILURE, "-n and --cache can only be specified once");
 390             }
 391             seen_cache = true;
 392             if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
 393                 errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg);
 394             }
 395             break;
 396 #ifdef CONFIG_LINUX_AIO
 397         case QEMU_NBD_OPT_AIO:
 398             if (seen_aio) {
 399                 errx(EXIT_FAILURE, "--aio can only be specified once");
 400             }
 401             seen_aio = true;
 402             if (!strcmp(optarg, "native")) {
 403                 flags |= BDRV_O_NATIVE_AIO;
 404             } else if (!strcmp(optarg, "threads")) {
 405                 /* this is the default */
 406             } else {
 407                errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg);
 408             }
 409             break;
 410 #endif
 411         case QEMU_NBD_OPT_DISCARD:
 412             if (seen_discard) {
 413                 errx(EXIT_FAILURE, "--discard can only be specified once");
 414             }
 415             seen_discard = true;
 416             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 417                 errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg);
 418             }
 419             break;
 420         case 'b':
 421             bindto = optarg;
 422             break;
 423         case 'p':
 424             li = strtol(optarg, &end, 0);
 425             if (*end) {
 426                 errx(EXIT_FAILURE, "Invalid port `%s'", optarg);
 427             }
 428             if (li < 1 || li > 65535) {
 429                 errx(EXIT_FAILURE, "Port out of range `%s'", optarg);
 430             }
 431             port = (uint16_t)li;
 432             break;
 433         case 'o':
 434                 dev_offset = strtoll (optarg, &end, 0);
 435             if (*end) {
 436                 errx(EXIT_FAILURE, "Invalid offset `%s'", optarg);
 437             }
 438             if (dev_offset < 0) {
 439                 errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
 440             }
 441             break;
 442         case 'l':
 443             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 444                 sn_opts = qemu_opts_parse(&internal_snapshot_opts, optarg, 0);
 445                 if (!sn_opts) {
 446                     errx(EXIT_FAILURE, "Failed in parsing snapshot param `%s'",
 447                          optarg);
 448                 }
 449             } else {
 450                 sn_id_or_name = optarg;
 451             }
 452             /* fall through */
 453         case 'r':
 454             nbdflags |= NBD_FLAG_READ_ONLY;
 455             flags &= ~BDRV_O_RDWR;
 456             break;
 457         case 'P':
 458             partition = strtol(optarg, &end, 0);
 459             if (*end)
 460                 errx(EXIT_FAILURE, "Invalid partition `%s'", optarg);
 461             if (partition < 1 || partition > 8)
 462                 errx(EXIT_FAILURE, "Invalid partition %d", partition);
 463             break;
 464         case 'k':
 465             sockpath = optarg;
 466             if (sockpath[0] != '/')
 467                 errx(EXIT_FAILURE, "socket path must be absolute\n");
 468             break;
 469         case 'd':
 470             disconnect = true;
 471             break;
 472         case 'c':
 473             device = optarg;
 474             break;
 475         case 'e':
 476             shared = strtol(optarg, &end, 0);
 477             if (*end) {
 478                 errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg);
 479             }
 480             if (shared < 1) {
 481                 errx(EXIT_FAILURE, "Shared device number must be greater than 0\n");
 482             }
 483             break;
 484         case 'f':
 485             fmt = optarg;
 486             break;
 487         case 't':
 488             persistent = 1;
 489             break;
 490         case 'v':
 491             verbose = 1;
 492             break;
 493         case 'V':
 494             version(argv[0]);
 495             exit(0);
 496             break;
 497         case 'h':
 498             usage(argv[0]);
 499             exit(0);
 500             break;
 501         case '?':
 502             errx(EXIT_FAILURE, "Try `%s --help' for more information.",
 503                  argv[0]);
 504         }
 505     }
 506
 507     if ((argc - optind) != 1) {
 508         errx(EXIT_FAILURE, "Invalid number of argument.\n"
 509              "Try `%s --help' for more information.",
 510              argv[0]);
 511     }
 512
 513     if (disconnect) {
 514         fd = open(argv[optind], O_RDWR);
 515         if (fd < 0) {
 516             err(EXIT_FAILURE, "Cannot open %s", argv[optind]);
 517         }
 518         nbd_disconnect(fd);
 519
 520         close(fd);
 521
 522         printf("%s disconnected\n", argv[optind]);
 523
 524         return 0;
 525     }
 526
 527     if (device && !verbose) {
 528         int stderr_fd[2];
 529         pid_t pid;
 530         int ret;
 531
 532         if (qemu_pipe(stderr_fd) < 0) {
 533             err(EXIT_FAILURE, "Error setting up communication pipe");
 534         }
 535
 536         /* Now daemonize, but keep a communication channel open to
 537          * print errors and exit with the proper status code.
 538          */
 539         pid = fork();
 540         if (pid == 0) {
 541             close(stderr_fd[0]);
 542             ret = qemu_daemon(1, 0);
 543
 544             /* Temporarily redirect stderr to the parent's pipe...  */
 545             dup2(stderr_fd[1], STDERR_FILENO);
 546             if (ret < 0) {
 547                 err(EXIT_FAILURE, "Failed to daemonize");
 548             }
 549
 550             /* ... close the descriptor we inherited and go on.  */
 551             close(stderr_fd[1]);
 552         } else {
 553             bool errors = false;
 554             char *buf;
 555
 556             /* In the parent.  Print error messages from the child until
 557              * it closes the pipe.
 558              */
 559             close(stderr_fd[1]);
 560             buf = g_malloc(1024);
 561             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 562                 errors = true;
 563                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 564                 if (ret < 0) {
 565                     exit(EXIT_FAILURE);
 566                 }
 567             }
 568             if (ret < 0) {
 569                 err(EXIT_FAILURE, "Cannot read from daemon");
 570             }
 571
 572             /* Usually the daemon should not print any message.
 573              * Exit with zero status in that case.
 574              */
 575             exit(errors);
 576         }
 577     }
 578
 579     if (device != NULL && sockpath == NULL) {
 580         sockpath = g_malloc(128);
 581         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 582     }
 583
 584     qemu_init_main_loop();
 585     bdrv_init();
 586     atexit(bdrv_close_all);
 587
 588     if (fmt) {
 589         drv = bdrv_find_format(fmt);
 590         if (!drv) {
 591             errx(EXIT_FAILURE, "Unknown file format '%s'", fmt);
 592         }
 593     } else {
 594         drv = NULL;
 595     }
 596
 597     bs = bdrv_new("hda");
 598     srcpath = argv[optind];
 599     ret = bdrv_open(bs, srcpath, NULL, flags, drv, &local_err);
 600     if (ret < 0) {
 601         errno = -ret;
 602         err(EXIT_FAILURE, "Failed to bdrv_open '%s': %s", argv[optind],
 603             error_get_pretty(local_err));
 604     }
 605
 606     if (sn_opts) {
 607         ret = bdrv_snapshot_load_tmp(bs,
 608                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
 609                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
 610                                      &local_err);
 611     } else if (sn_id_or_name) {
 612         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
 613                                                    &local_err);
 614     }
 615     if (ret < 0) {
 616         errno = -ret;
 617         err(EXIT_FAILURE,
 618             "Failed to load snapshot: %s",
 619             error_get_pretty(local_err));
 620     }
 621
 622     fd_size = bdrv_getlength(bs);
 623
 624     if (partition != -1) {
 625         ret = find_partition(bs, partition, &dev_offset, &fd_size);
 626         if (ret < 0) {
 627             errno = -ret;
 628             err(EXIT_FAILURE, "Could not find partition %d", partition);
 629         }
 630     }
 631
 632     exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed);
 633
 634     if (sockpath) {
 635         fd = unix_socket_incoming(sockpath);
 636     } else {
 637         fd = tcp_socket_incoming(bindto, port);
 638     }
 639
 640     if (fd < 0) {
 641         return 1;
 642     }
 643
 644     if (device) {
 645         int ret;
 646
 647         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
 648         if (ret != 0) {
 649             errx(EXIT_FAILURE, "Failed to create client thread: %s",
 650                  strerror(ret));
 651         }
 652     } else {
 653         /* Shut up GCC warnings.  */
 654         memset(&client_thread, 0, sizeof(client_thread));
 655     }
 656
 657     qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
 658                          (void *)(uintptr_t)fd);
 659
 660     /* now when the initialization is (almost) complete, chdir("/")
 661      * to free any busy filesystems */
 662     if (chdir("/") < 0) {
 663         err(EXIT_FAILURE, "Could not chdir to root directory");
 664     }
 665
 666     state = RUNNING;
 667     do {
 668         main_loop_wait(false);
 669         if (state == TERMINATE) {
 670             state = TERMINATING;
 671             nbd_export_close(exp);
 672             nbd_export_put(exp);
 673             exp = NULL;
 674         }
 675     } while (state != TERMINATED);
 676
 677     bdrv_close(bs);
 678     if (sockpath) {
 679         unlink(sockpath);
 680     }
 681
 682     if (sn_opts) {
 683         qemu_opts_del(sn_opts);
 684     }
 685
 686     if (device) {
 687         void *ret;
 688         pthread_join(client_thread, &ret);
 689         exit(ret != NULL);
 690     } else {
 691         exit(EXIT_SUCCESS);
 692     }
 693 }