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 "sysemu/block-backend.h"
  21 #include "block/block_int.h"
  22 #include "block/nbd.h"
  23 #include "qemu/main-loop.h"
  24 #include "qemu/sockets.h"
  25 #include "qemu/error-report.h"
  26 #include "block/snapshot.h"
  27 #include "qapi/util.h"
  28
  29 #include <stdarg.h>
  30 #include <stdio.h>
  31 #include <getopt.h>
  32 #include <err.h>
  33 #include <sys/types.h>
  34 #include <sys/socket.h>
  35 #include <netinet/in.h>
  36 #include <netinet/tcp.h>
  37 #include <arpa/inet.h>
  38 #include <signal.h>
  39 #include <libgen.h>
  40 #include <pthread.h>
  41
  42 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
  43 #define QEMU_NBD_OPT_CACHE         1
  44 #define QEMU_NBD_OPT_AIO           2
  45 #define QEMU_NBD_OPT_DISCARD       3
  46 #define QEMU_NBD_OPT_DETECT_ZEROES 4
  47
  48 static NBDExport *exp;
  49 static int verbose;
  50 static char *srcpath;
  51 static char *sockpath;
  52 static int persistent = 0;
  53 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
  54 static int shared = 1;
  55 static int nb_fds;
  56
  57 static void usage(const char *name)
  58 {
  59     (printf) (
  60 "Usage: %s [OPTIONS] FILE\n"
  61 "QEMU Disk Network Block Device Server\n"
  62 "\n"
  63 "  -h, --help                display this help and exit\n"
  64 "  -V, --version             output version information and exit\n"
  65 "\n"
  66 "Connection properties:\n"
  67 "  -p, --port=PORT           port to listen on (default `%d')\n"
  68 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  69 "  -k, --socket=PATH         path to the unix socket\n"
  70 "                            (default '"SOCKET_PATH"')\n"
  71 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
  72 "  -t, --persistent          don't exit on the last connection\n"
  73 "  -v, --verbose             display extra debugging information\n"
  74 "\n"
  75 "Exposing part of the image:\n"
  76 "  -o, --offset=OFFSET       offset into the image\n"
  77 "  -P, --partition=NUM       only expose partition NUM\n"
  78 "\n"
  79 #ifdef __linux__
  80 "Kernel NBD client support:\n"
  81 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
  82 "  -d, --disconnect          disconnect the specified device\n"
  83 "\n"
  84 #endif
  85 "\n"
  86 "Block device options:\n"
  87 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
  88 "  -r, --read-only           export read-only\n"
  89 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
  90 "                            file with backing_file=FILE, redirect the write to\n"
  91 "                            the temporary one\n"
  92 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
  93 "                            load an internal snapshot inside FILE and export it\n"
  94 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
  95 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
  96 "                            '[ID_OR_NAME]'\n"
  97 "  -n, --nocache             disable host cache\n"
  98 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
  99 #ifdef CONFIG_LINUX_AIO
 100 "      --aio=MODE            set AIO mode (native or threads)\n"
 101 #endif
 102 "      --discard=MODE        set discard mode (ignore, unmap)\n"
 103 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, discard)\n"
 104 "\n"
 105 "Report bugs to <qemu-devel@nongnu.org>\n"
 106     , name, NBD_DEFAULT_PORT, "DEVICE");
 107 }
 108
 109 static void version(const char *name)
 110 {
 111     printf(
 112 "%s version 0.0.1\n"
 113 "Written by Anthony Liguori.\n"
 114 "\n"
 115 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
 116 "This is free software; see the source for copying conditions.  There is NO\n"
 117 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 118     , name);
 119 }
 120
 121 struct partition_record
 122 {
 123     uint8_t bootable;
 124     uint8_t start_head;
 125     uint32_t start_cylinder;
 126     uint8_t start_sector;
 127     uint8_t system;
 128     uint8_t end_head;
 129     uint8_t end_cylinder;
 130     uint8_t end_sector;
 131     uint32_t start_sector_abs;
 132     uint32_t nb_sectors_abs;
 133 };
 134
 135 static void read_partition(uint8_t *p, struct partition_record *r)
 136 {
 137     r->bootable = p[0];
 138     r->start_head = p[1];
 139     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
 140     r->start_sector = p[2] & 0x3f;
 141     r->system = p[4];
 142     r->end_head = p[5];
 143     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
 144     r->end_sector = p[6] & 0x3f;
 145
 146     r->start_sector_abs = le32_to_cpup((uint32_t *)(p +  8));
 147     r->nb_sectors_abs   = le32_to_cpup((uint32_t *)(p + 12));
 148 }
 149
 150 static int find_partition(BlockBackend *blk, int partition,
 151                           off_t *offset, off_t *size)
 152 {
 153     struct partition_record mbr[4];
 154     uint8_t data[512];
 155     int i;
 156     int ext_partnum = 4;
 157     int ret;
 158
 159     if ((ret = blk_read(blk, 0, data, 1)) < 0) {
 160         errno = -ret;
 161         err(EXIT_FAILURE, "error while reading");
 162     }
 163
 164     if (data[510] != 0x55 || data[511] != 0xaa) {
 165         return -EINVAL;
 166     }
 167
 168     for (i = 0; i < 4; i++) {
 169         read_partition(&data[446 + 16 * i], &mbr[i]);
 170
 171         if (!mbr[i].system || !mbr[i].nb_sectors_abs) {
 172             continue;
 173         }
 174
 175         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
 176             struct partition_record ext[4];
 177             uint8_t data1[512];
 178             int j;
 179
 180             if ((ret = blk_read(blk, mbr[i].start_sector_abs, data1, 1)) < 0) {
 181                 errno = -ret;
 182                 err(EXIT_FAILURE, "error while reading");
 183             }
 184
 185             for (j = 0; j < 4; j++) {
 186                 read_partition(&data1[446 + 16 * j], &ext[j]);
 187                 if (!ext[j].system || !ext[j].nb_sectors_abs) {
 188                     continue;
 189                 }
 190
 191                 if ((ext_partnum + j + 1) == partition) {
 192                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
 193                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
 194                     return 0;
 195                 }
 196             }
 197             ext_partnum += 4;
 198         } else if ((i + 1) == partition) {
 199             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
 200             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
 201             return 0;
 202         }
 203     }
 204
 205     return -ENOENT;
 206 }
 207
 208 static void termsig_handler(int signum)
 209 {
 210     state = TERMINATE;
 211     qemu_notify_event();
 212 }
 213
 214 static void combine_addr(char *buf, size_t len, const char* address,
 215                          uint16_t port)
 216 {
 217     /* If the address-part contains a colon, it's an IPv6 IP so needs [] */
 218     if (strstr(address, ":")) {
 219         snprintf(buf, len, "[%s]:%u", address, port);
 220     } else {
 221         snprintf(buf, len, "%s:%u", address, port);
 222     }
 223 }
 224
 225 static int tcp_socket_incoming(const char *address, uint16_t port)
 226 {
 227     char address_and_port[128];
 228     Error *local_err = NULL;
 229
 230     combine_addr(address_and_port, 128, address, port);
 231     int fd = inet_listen(address_and_port, NULL, 0, SOCK_STREAM, 0, &local_err);
 232
 233     if (local_err != NULL) {
 234         error_report_err(local_err);
 235     }
 236     return fd;
 237 }
 238
 239 static int unix_socket_incoming(const char *path)
 240 {
 241     Error *local_err = NULL;
 242     int fd = unix_listen(path, NULL, 0, &local_err);
 243
 244     if (local_err != NULL) {
 245         error_report_err(local_err);
 246     }
 247     return fd;
 248 }
 249
 250 static int unix_socket_outgoing(const char *path)
 251 {
 252     Error *local_err = NULL;
 253     int fd = unix_connect(path, &local_err);
 254
 255     if (local_err != NULL) {
 256         error_report_err(local_err);
 257     }
 258     return fd;
 259 }
 260
 261 static void *show_parts(void *arg)
 262 {
 263     char *device = arg;
 264     int nbd;
 265
 266     /* linux just needs an open() to trigger
 267      * the partition table update
 268      * but remember to load the module with max_part != 0 :
 269      *     modprobe nbd max_part=63
 270      */
 271     nbd = open(device, O_RDWR);
 272     if (nbd >= 0) {
 273         close(nbd);
 274     }
 275     return NULL;
 276 }
 277
 278 static void *nbd_client_thread(void *arg)
 279 {
 280     char *device = arg;
 281     off_t size;
 282     uint32_t nbdflags;
 283     int fd, sock;
 284     int ret;
 285     pthread_t show_parts_thread;
 286     Error *local_error = NULL;
 287
 288     sock = unix_socket_outgoing(sockpath);
 289     if (sock < 0) {
 290         goto out;
 291     }
 292
 293     ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
 294                                 &size, &local_error);
 295     if (ret < 0) {
 296         if (local_error) {
 297             fprintf(stderr, "%s\n", error_get_pretty(local_error));
 298             error_free(local_error);
 299         }
 300         goto out_socket;
 301     }
 302
 303     fd = open(device, O_RDWR);
 304     if (fd < 0) {
 305         /* Linux-only, we can use %m in printf.  */
 306         fprintf(stderr, "Failed to open %s: %m\n", device);
 307         goto out_socket;
 308     }
 309
 310     ret = nbd_init(fd, sock, nbdflags, size);
 311     if (ret < 0) {
 312         goto out_fd;
 313     }
 314
 315     /* update partition table */
 316     pthread_create(&show_parts_thread, NULL, show_parts, device);
 317
 318     if (verbose) {
 319         fprintf(stderr, "NBD device %s is now connected to %s\n",
 320                 device, srcpath);
 321     } else {
 322         /* Close stderr so that the qemu-nbd process exits.  */
 323         dup2(STDOUT_FILENO, STDERR_FILENO);
 324     }
 325
 326     ret = nbd_client(fd);
 327     if (ret) {
 328         goto out_fd;
 329     }
 330     close(fd);
 331     kill(getpid(), SIGTERM);
 332     return (void *) EXIT_SUCCESS;
 333
 334 out_fd:
 335     close(fd);
 336 out_socket:
 337     closesocket(sock);
 338 out:
 339     kill(getpid(), SIGTERM);
 340     return (void *) EXIT_FAILURE;
 341 }
 342
 343 static int nbd_can_accept(void *opaque)
 344 {
 345     return nb_fds < shared;
 346 }
 347
 348 static void nbd_export_closed(NBDExport *exp)
 349 {
 350     assert(state == TERMINATING);
 351     state = TERMINATED;
 352 }
 353
 354 static void nbd_client_closed(NBDClient *client)
 355 {
 356     nb_fds--;
 357     if (nb_fds == 0 && !persistent && state == RUNNING) {
 358         state = TERMINATE;
 359     }
 360     qemu_notify_event();
 361     nbd_client_put(client);
 362 }
 363
 364 static void nbd_accept(void *opaque)
 365 {
 366     int server_fd = (uintptr_t) opaque;
 367     struct sockaddr_in addr;
 368     socklen_t addr_len = sizeof(addr);
 369
 370     int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
 371     if (fd < 0) {
 372         perror("accept");
 373         return;
 374     }
 375
 376     if (state >= TERMINATE) {
 377         close(fd);
 378         return;
 379     }
 380
 381     if (nbd_client_new(exp, fd, nbd_client_closed)) {
 382         nb_fds++;
 383     } else {
 384         shutdown(fd, 2);
 385         close(fd);
 386     }
 387 }
 388
 389 int main(int argc, char **argv)
 390 {
 391     BlockBackend *blk;
 392     BlockDriverState *bs;
 393     off_t dev_offset = 0;
 394     uint32_t nbdflags = 0;
 395     bool disconnect = false;
 396     const char *bindto = "0.0.0.0";
 397     char *device = NULL;
 398     int port = NBD_DEFAULT_PORT;
 399     off_t fd_size;
 400     QemuOpts *sn_opts = NULL;
 401     const char *sn_id_or_name = NULL;
 402     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:";
 403     struct option lopt[] = {
 404         { "help", 0, NULL, 'h' },
 405         { "version", 0, NULL, 'V' },
 406         { "bind", 1, NULL, 'b' },
 407         { "port", 1, NULL, 'p' },
 408         { "socket", 1, NULL, 'k' },
 409         { "offset", 1, NULL, 'o' },
 410         { "read-only", 0, NULL, 'r' },
 411         { "partition", 1, NULL, 'P' },
 412         { "connect", 1, NULL, 'c' },
 413         { "disconnect", 0, NULL, 'd' },
 414         { "snapshot", 0, NULL, 's' },
 415         { "load-snapshot", 1, NULL, 'l' },
 416         { "nocache", 0, NULL, 'n' },
 417         { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
 418 #ifdef CONFIG_LINUX_AIO
 419         { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
 420 #endif
 421         { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
 422         { "detect-zeroes", 1, NULL, QEMU_NBD_OPT_DETECT_ZEROES },
 423         { "shared", 1, NULL, 'e' },
 424         { "format", 1, NULL, 'f' },
 425         { "persistent", 0, NULL, 't' },
 426         { "verbose", 0, NULL, 'v' },
 427         { NULL, 0, NULL, 0 }
 428     };
 429     int ch;
 430     int opt_ind = 0;
 431     int li;
 432     char *end;
 433     int flags = BDRV_O_RDWR;
 434     int partition = -1;
 435     int ret = 0;
 436     int fd;
 437     bool seen_cache = false;
 438     bool seen_discard = false;
 439 #ifdef CONFIG_LINUX_AIO
 440     bool seen_aio = false;
 441 #endif
 442     pthread_t client_thread;
 443     const char *fmt = NULL;
 444     Error *local_err = NULL;
 445     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 446     QDict *options = NULL;
 447
 448     /* The client thread uses SIGTERM to interrupt the server.  A signal
 449      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 450      */
 451     struct sigaction sa_sigterm;
 452     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 453     sa_sigterm.sa_handler = termsig_handler;
 454     sigaction(SIGTERM, &sa_sigterm, NULL);
 455     qemu_init_exec_dir(argv[0]);
 456
 457     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 458         switch (ch) {
 459         case 's':
 460             flags |= BDRV_O_SNAPSHOT;
 461             break;
 462         case 'n':
 463             optarg = (char *) "none";
 464             /* fallthrough */
 465         case QEMU_NBD_OPT_CACHE:
 466             if (seen_cache) {
 467                 errx(EXIT_FAILURE, "-n and --cache can only be specified once");
 468             }
 469             seen_cache = true;
 470             if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
 471                 errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg);
 472             }
 473             break;
 474 #ifdef CONFIG_LINUX_AIO
 475         case QEMU_NBD_OPT_AIO:
 476             if (seen_aio) {
 477                 errx(EXIT_FAILURE, "--aio can only be specified once");
 478             }
 479             seen_aio = true;
 480             if (!strcmp(optarg, "native")) {
 481                 flags |= BDRV_O_NATIVE_AIO;
 482             } else if (!strcmp(optarg, "threads")) {
 483                 /* this is the default */
 484             } else {
 485                errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg);
 486             }
 487             break;
 488 #endif
 489         case QEMU_NBD_OPT_DISCARD:
 490             if (seen_discard) {
 491                 errx(EXIT_FAILURE, "--discard can only be specified once");
 492             }
 493             seen_discard = true;
 494             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 495                 errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg);
 496             }
 497             break;
 498         case QEMU_NBD_OPT_DETECT_ZEROES:
 499             detect_zeroes =
 500                 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
 501                                 optarg,
 502                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_MAX,
 503                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 504                                 &local_err);
 505             if (local_err) {
 506                 errx(EXIT_FAILURE, "Failed to parse detect_zeroes mode: %s",
 507                      error_get_pretty(local_err));
 508             }
 509             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 510                 !(flags & BDRV_O_UNMAP)) {
 511                 errx(EXIT_FAILURE, "setting detect-zeroes to unmap is not allowed "
 512                                    "without setting discard operation to unmap");
 513             }
 514             break;
 515         case 'b':
 516             bindto = optarg;
 517             break;
 518         case 'p':
 519             li = strtol(optarg, &end, 0);
 520             if (*end) {
 521                 errx(EXIT_FAILURE, "Invalid port `%s'", optarg);
 522             }
 523             if (li < 1 || li > 65535) {
 524                 errx(EXIT_FAILURE, "Port out of range `%s'", optarg);
 525             }
 526             port = (uint16_t)li;
 527             break;
 528         case 'o':
 529                 dev_offset = strtoll (optarg, &end, 0);
 530             if (*end) {
 531                 errx(EXIT_FAILURE, "Invalid offset `%s'", optarg);
 532             }
 533             if (dev_offset < 0) {
 534                 errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
 535             }
 536             break;
 537         case 'l':
 538             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 539                 sn_opts = qemu_opts_parse(&internal_snapshot_opts, optarg, 0);
 540                 if (!sn_opts) {
 541                     errx(EXIT_FAILURE, "Failed in parsing snapshot param `%s'",
 542                          optarg);
 543                 }
 544             } else {
 545                 sn_id_or_name = optarg;
 546             }
 547             /* fall through */
 548         case 'r':
 549             nbdflags |= NBD_FLAG_READ_ONLY;
 550             flags &= ~BDRV_O_RDWR;
 551             break;
 552         case 'P':
 553             partition = strtol(optarg, &end, 0);
 554             if (*end) {
 555                 errx(EXIT_FAILURE, "Invalid partition `%s'", optarg);
 556             }
 557             if (partition < 1 || partition > 8) {
 558                 errx(EXIT_FAILURE, "Invalid partition %d", partition);
 559             }
 560             break;
 561         case 'k':
 562             sockpath = optarg;
 563             if (sockpath[0] != '/') {
 564                 errx(EXIT_FAILURE, "socket path must be absolute\n");
 565             }
 566             break;
 567         case 'd':
 568             disconnect = true;
 569             break;
 570         case 'c':
 571             device = optarg;
 572             break;
 573         case 'e':
 574             shared = strtol(optarg, &end, 0);
 575             if (*end) {
 576                 errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg);
 577             }
 578             if (shared < 1) {
 579                 errx(EXIT_FAILURE, "Shared device number must be greater than 0\n");
 580             }
 581             break;
 582         case 'f':
 583             fmt = optarg;
 584             break;
 585         case 't':
 586             persistent = 1;
 587             break;
 588         case 'v':
 589             verbose = 1;
 590             break;
 591         case 'V':
 592             version(argv[0]);
 593             exit(0);
 594             break;
 595         case 'h':
 596             usage(argv[0]);
 597             exit(0);
 598             break;
 599         case '?':
 600             errx(EXIT_FAILURE, "Try `%s --help' for more information.",
 601                  argv[0]);
 602         }
 603     }
 604
 605     if ((argc - optind) != 1) {
 606         errx(EXIT_FAILURE, "Invalid number of argument.\n"
 607              "Try `%s --help' for more information.",
 608              argv[0]);
 609     }
 610
 611     if (disconnect) {
 612         fd = open(argv[optind], O_RDWR);
 613         if (fd < 0) {
 614             err(EXIT_FAILURE, "Cannot open %s", argv[optind]);
 615         }
 616         nbd_disconnect(fd);
 617
 618         close(fd);
 619
 620         printf("%s disconnected\n", argv[optind]);
 621
 622         return 0;
 623     }
 624
 625     if (device && !verbose) {
 626         int stderr_fd[2];
 627         pid_t pid;
 628         int ret;
 629
 630         if (qemu_pipe(stderr_fd) < 0) {
 631             err(EXIT_FAILURE, "Error setting up communication pipe");
 632         }
 633
 634         /* Now daemonize, but keep a communication channel open to
 635          * print errors and exit with the proper status code.
 636          */
 637         pid = fork();
 638         if (pid < 0) {
 639             err(EXIT_FAILURE, "Failed to fork");
 640         } else if (pid == 0) {
 641             close(stderr_fd[0]);
 642             ret = qemu_daemon(1, 0);
 643
 644             /* Temporarily redirect stderr to the parent's pipe...  */
 645             dup2(stderr_fd[1], STDERR_FILENO);
 646             if (ret < 0) {
 647                 err(EXIT_FAILURE, "Failed to daemonize");
 648             }
 649
 650             /* ... close the descriptor we inherited and go on.  */
 651             close(stderr_fd[1]);
 652         } else {
 653             bool errors = false;
 654             char *buf;
 655
 656             /* In the parent.  Print error messages from the child until
 657              * it closes the pipe.
 658              */
 659             close(stderr_fd[1]);
 660             buf = g_malloc(1024);
 661             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 662                 errors = true;
 663                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 664                 if (ret < 0) {
 665                     exit(EXIT_FAILURE);
 666                 }
 667             }
 668             if (ret < 0) {
 669                 err(EXIT_FAILURE, "Cannot read from daemon");
 670             }
 671
 672             /* Usually the daemon should not print any message.
 673              * Exit with zero status in that case.
 674              */
 675             exit(errors);
 676         }
 677     }
 678
 679     if (device != NULL && sockpath == NULL) {
 680         sockpath = g_malloc(128);
 681         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 682     }
 683
 684     if (qemu_init_main_loop(&local_err)) {
 685         error_report_err(local_err);
 686         exit(EXIT_FAILURE);
 687     }
 688     bdrv_init();
 689     atexit(bdrv_close_all);
 690
 691     if (fmt) {
 692         options = qdict_new();
 693         qdict_put(options, "driver", qstring_from_str(fmt));
 694     }
 695
 696     srcpath = argv[optind];
 697     blk = blk_new_open("hda", srcpath, NULL, options, flags, &local_err);
 698     if (!blk) {
 699         errx(EXIT_FAILURE, "Failed to blk_new_open '%s': %s", argv[optind],
 700              error_get_pretty(local_err));
 701     }
 702     bs = blk_bs(blk);
 703
 704     if (sn_opts) {
 705         ret = bdrv_snapshot_load_tmp(bs,
 706                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
 707                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
 708                                      &local_err);
 709     } else if (sn_id_or_name) {
 710         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
 711                                                    &local_err);
 712     }
 713     if (ret < 0) {
 714         errno = -ret;
 715         err(EXIT_FAILURE,
 716             "Failed to load snapshot: %s",
 717             error_get_pretty(local_err));
 718     }
 719
 720     bs->detect_zeroes = detect_zeroes;
 721     fd_size = blk_getlength(blk);
 722     if (fd_size < 0) {
 723         errx(EXIT_FAILURE, "Failed to determine the image length: %s",
 724              strerror(-fd_size));
 725     }
 726
 727     if (partition != -1) {
 728         ret = find_partition(blk, partition, &dev_offset, &fd_size);
 729         if (ret < 0) {
 730             errno = -ret;
 731             err(EXIT_FAILURE, "Could not find partition %d", partition);
 732         }
 733     }
 734
 735     exp = nbd_export_new(blk, dev_offset, fd_size, nbdflags, nbd_export_closed,
 736                          &local_err);
 737     if (!exp) {
 738         errx(EXIT_FAILURE, "%s", error_get_pretty(local_err));
 739     }
 740
 741     if (sockpath) {
 742         fd = unix_socket_incoming(sockpath);
 743     } else {
 744         fd = tcp_socket_incoming(bindto, port);
 745     }
 746
 747     if (fd < 0) {
 748         return 1;
 749     }
 750
 751     if (device) {
 752         int ret;
 753
 754         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
 755         if (ret != 0) {
 756             errx(EXIT_FAILURE, "Failed to create client thread: %s",
 757                  strerror(ret));
 758         }
 759     } else {
 760         /* Shut up GCC warnings.  */
 761         memset(&client_thread, 0, sizeof(client_thread));
 762     }
 763
 764     qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
 765                          (void *)(uintptr_t)fd);
 766
 767     /* now when the initialization is (almost) complete, chdir("/")
 768      * to free any busy filesystems */
 769     if (chdir("/") < 0) {
 770         err(EXIT_FAILURE, "Could not chdir to root directory");
 771     }
 772
 773     state = RUNNING;
 774     do {
 775         main_loop_wait(false);
 776         if (state == TERMINATE) {
 777             state = TERMINATING;
 778             nbd_export_close(exp);
 779             nbd_export_put(exp);
 780             exp = NULL;
 781         }
 782     } while (state != TERMINATED);
 783
 784     blk_unref(blk);
 785     if (sockpath) {
 786         unlink(sockpath);
 787     }
 788
 789     qemu_opts_del(sn_opts);
 790
 791     if (device) {
 792         void *ret;
 793         pthread_join(client_thread, &ret);
 794         exit(ret != NULL);
 795     } else {
 796         exit(EXIT_SUCCESS);
 797     }
 798 }