nbd-client.c

   1 /*
   2  * Open connection for network block device
   3  *
   4  * Copyright 1997,1998 Pavel Machek, distribute under GPL
   5  *  <pavel@atrey.karlin.mff.cuni.cz>
   6  * Copyright (c) 2002 - 2011 Wouter Verhelst <w@uter.be>
   7  *
   8  * Version 1.0 - 64bit issues should be fixed, now
   9  * Version 1.1 - added bs (blocksize) option (Alexey Guzeev, aga@permonline.ru)
  10  * Version 1.2 - I added new option '-d' to send the disconnect request
  11  * Version 2.0 - Version synchronised with server
  12  * Version 2.1 - Check for disconnection before INIT_PASSWD is received
  13  *      to make errormsg a bit more helpful in case the server can't
  14  *      open the exported file.
  15  * 16/03/2010 - Add IPv6 support.
  16  *      Kitt Tientanopajai <kitt@kitty.in.th>
  17  *      Neutron Soutmun <neo.neutron@gmail.com>
  18  *      Suriya Soutmun <darksolar@gmail.com>
  19  */
  20
  21 #include "config.h"
  22 #include "lfs.h"
  23
  24 #include <sys/ioctl.h>
  25 #include <sys/socket.h>
  26 #include <sys/types.h>
  27 #include <unistd.h>
  28 #include <netinet/tcp.h>
  29 #include <netinet/in.h>
  30 #include <netdb.h>
  31 #include "netdb-compat.h"
  32 #include <stdio.h>
  33 #include <fcntl.h>
  34 #include <syslog.h>
  35 #include <stdlib.h>
  36 #include <sys/mount.h>
  37 #include <sys/mman.h>
  38 #include <signal.h>
  39 #include <errno.h>
  40 #include <getopt.h>
  41 #include <stdarg.h>
  42
  43 #include <linux/ioctl.h>
  44 #define MY_NAME "nbd_client"
  45 #include "cliserv.h"
  46
  47 #ifdef WITH_SDP
  48 #include <sdp_inet.h>
  49 #endif
  50
  51 #define NBDC_DO_LIST 1
  52
  53 int check_conn(char* devname, int do_print) {
  54         char buf[256];
  55         char* p;
  56         int fd;
  57         int len;
  58
  59         if( (p=strrchr(devname, '/')) ) {
  60                 devname=p+1;
  61         }
  62         if((p=strchr(devname, 'p'))) {
  63                 /* We can't do checks on partitions. */
  64                 *p='\0';
  65         }
  66         snprintf(buf, 256, "/sys/block/%s/pid", devname);
  67         if((fd=open(buf, O_RDONLY))<0) {
  68                 if(errno==ENOENT) {
  69                         return 1;
  70                 } else {
  71                         return 2;
  72                 }
  73         }
  74         len=read(fd, buf, 256);
  75         buf[len-1]='\0';
  76         if(do_print) printf("%s\n", buf);
  77         return 0;
  78 }
  79
  80 int opennet(char *name, char* portstr, int sdp) {
  81         int sock;
  82         struct addrinfo hints;
  83         struct addrinfo *ai = NULL;
  84         struct addrinfo *rp = NULL;
  85         int e;
  86
  87         memset(&hints,'\0',sizeof(hints));
  88         hints.ai_family = AF_UNSPEC;
  89         hints.ai_socktype = SOCK_STREAM;
  90         hints.ai_flags = AI_ADDRCONFIG | AI_NUMERICSERV;
  91         hints.ai_protocol = IPPROTO_TCP;
  92
  93         e = getaddrinfo(name, portstr, &hints, &ai);
  94
  95         if(e != 0) {
  96                 fprintf(stderr, "getaddrinfo failed: %s\n", gai_strerror(e));
  97                 freeaddrinfo(ai);
  98                 return -1;
  99         }
 100
 101         if(sdp) {
 102 #ifdef WITH_SDP
 103                 if (ai->ai_family == AF_INET)
 104                         ai->ai_family = AF_INET_SDP;
 105                 else (ai->ai_family == AF_INET6)
 106                         ai->ai_family = AF_INET6_SDP;
 107 #else
 108                 err("Can't do SDP: I was not compiled with SDP support!");
 109 #endif
 110         }
 111
 112         for(rp = ai; rp != NULL; rp = rp->ai_next) {
 113                 sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 114
 115                 if(sock == -1)
 116                         continue;       /* error */
 117
 118                 if(connect(sock, rp->ai_addr, rp->ai_addrlen) != -1)
 119                         break;          /* success */
 120         }
 121
 122         if (rp == NULL) {
 123                 err_nonfatal("Socket failed: %m");
 124                 return -1;
 125         }
 126
 127         setmysockopt(sock);
 128
 129         freeaddrinfo(ai);
 130         return sock;
 131 }
 132
 133 void ask_list(int sock) {
 134         uint32_t opt;
 135         uint32_t opt_server;
 136         uint32_t len;
 137         uint32_t reptype;
 138         uint64_t magic;
 139         const int BUF_SIZE = 1024;
 140         char buf[BUF_SIZE];
 141
 142         magic = ntohll(opts_magic);
 143         if (write(sock, &magic, sizeof(magic)) < 0)
 144                 err("Failed/2.2: %m");
 145
 146         /* Ask for the list */
 147         opt = htonl(NBD_OPT_LIST);
 148         if(write(sock, &opt, sizeof(opt)) < 0) {
 149                 err("writing list option failed: %m");
 150         }
 151         /* Send the length (zero) */
 152         len = htonl(0);
 153         if(write(sock, &len, sizeof(len)) < 0) {
 154                 err("writing length failed: %m");
 155         }
 156         /* newline, move away from the "Negotiation:" line */
 157         printf("\n");
 158         do {
 159                 memset(buf, 0, 1024);
 160                 if(read(sock, &magic, sizeof(magic)) < 0) {
 161                         err("Reading magic from server: %m");
 162                 }
 163                 if(read(sock, &opt_server, sizeof(opt_server)) < 0) {
 164                         err("Reading option: %m");
 165                 }
 166                 if(read(sock, &reptype, sizeof(reptype)) <0) {
 167                         err("Reading reply from server: %m");
 168                 }
 169                 if(read(sock, &len, sizeof(len)) < 0) {
 170                         err("Reading length from server: %m");
 171                 }
 172                 magic=ntohll(magic);
 173                 len=ntohl(len);
 174                 reptype=ntohl(reptype);
 175                 if(magic != rep_magic) {
 176                         err("Not enough magic from server");
 177                 }
 178                 if(reptype & NBD_REP_FLAG_ERROR) {
 179                         switch(reptype) {
 180                                 case NBD_REP_ERR_POLICY:
 181                                         fprintf(stderr, "\nE: listing not allowed by server.\n");
 182                                         break;
 183                                 default:
 184                                         fprintf(stderr, "\nE: unexpected error from server.\n");
 185                                         break;
 186                         }
 187                         if(len) {
 188                                 if(read(sock, buf, len) < 0) {
 189                                         fprintf(stderr, "\nE: could not read error message from server\n");
 190                                 }
 191                                 fprintf(stderr, "Server said: %s\n", buf);
 192                         }
 193                         exit(EXIT_FAILURE);
 194                 } else {
 195                         if(len) {
 196                                 if(reptype != NBD_REP_SERVER) {
 197                                         err("Server sent us a reply we don't understand!");
 198                                 }
 199                                 if(read(sock, &len, sizeof(len)) < 0) {
 200                                         fprintf(stderr, "\nE: could not read export name length from server\n");
 201                                         exit(EXIT_FAILURE);
 202                                 }
 203                                 len=ntohl(len);
 204                                 if (len >= BUF_SIZE) {
 205                                         fprintf(stderr, "\nE: export name on server too long\n");
 206                                         exit(EXIT_FAILURE);
 207                                 }
 208                                 if(read(sock, buf, len) < 0) {
 209                                         fprintf(stderr, "\nE: could not read export name from server\n");
 210                                         exit(EXIT_FAILURE);
 211                                 }
 212                                 buf[len] = 0;
 213                                 printf("%s\n", buf);
 214                         }
 215                 }
 216         } while(reptype != NBD_REP_ACK);
 217         opt=htonl(NBD_OPT_ABORT);
 218         len=htonl(0);
 219         magic=htonll(opts_magic);
 220         if (write(sock, &magic, sizeof(magic)) < 0)
 221                 err("Failed/2.2: %m");
 222         if (write(sock, &opt, sizeof(opt)) < 0)
 223                 err("Failed writing abort");
 224         if (write(sock, &len, sizeof(len)) < 0)
 225                 err("Failed writing length");
 226 }
 227
 228 void negotiate(int sock, u64 *rsize64, u32 *flags, char* name, uint32_t needed_flags, uint32_t client_flags, uint32_t do_opts) {
 229         u64 magic, size64;
 230         uint16_t tmp;
 231         char buf[256] = "\0\0\0\0\0\0\0\0\0";
 232
 233         printf("Negotiation: ");
 234         if (read(sock, buf, 8) < 0)
 235                 err("Failed/1: %m");
 236         if (strlen(buf)==0)
 237                 err("Server closed connection");
 238         if (strcmp(buf, INIT_PASSWD))
 239                 err("INIT_PASSWD bad");
 240         printf(".");
 241         if (read(sock, &magic, sizeof(magic)) < 0)
 242                 err("Failed/2: %m");
 243         magic = ntohll(magic);
 244         if(name) {
 245                 uint32_t opt;
 246                 uint32_t namesize;
 247
 248                 if (magic != opts_magic) {
 249                         if(magic == cliserv_magic) {
 250                                 err("It looks like you're trying to connect to an oldstyle server with a named export. This won't work.");
 251                         }
 252                 }
 253                 printf(".");
 254                 if(read(sock, &tmp, sizeof(uint16_t)) < 0) {
 255                         err("Failed reading flags: %m");
 256                 }
 257                 *flags = ((u32)ntohs(tmp));
 258                 if((needed_flags & *flags) != needed_flags) {
 259                         /* There's currently really only one reason why this
 260                          * check could possibly fail, but we may need to change
 261                          * this error message in the future... */
 262                         fprintf(stderr, "\nE: Server does not support listing exports\n");
 263                         exit(EXIT_FAILURE);
 264                 }
 265
 266                 client_flags = htonl(client_flags);
 267                 if (write(sock, &client_flags, sizeof(client_flags)) < 0)
 268                         err("Failed/2.1: %m");
 269
 270                 if(do_opts & NBDC_DO_LIST) {
 271                         ask_list(sock);
 272                         exit(EXIT_SUCCESS);
 273                 }
 274
 275                 /* Write the export name that we're after */
 276                 magic = htonll(opts_magic);
 277                 if (write(sock, &magic, sizeof(magic)) < 0)
 278                         err("Failed/2.2: %m");
 279
 280                 opt = ntohl(NBD_OPT_EXPORT_NAME);
 281                 if (write(sock, &opt, sizeof(opt)) < 0)
 282                         err("Failed/2.3: %m");
 283                 namesize = (u32)strlen(name);
 284                 namesize = ntohl(namesize);
 285                 if (write(sock, &namesize, sizeof(namesize)) < 0)
 286                         err("Failed/2.4: %m");
 287                 if (write(sock, name, strlen(name)) < 0)
 288                         err("Failed/2.4: %m");
 289         } else {
 290                 if (magic != cliserv_magic) {
 291                         if(magic != opts_magic)
 292                                 err("Not enough cliserv_magic");
 293                         else
 294                                 err("It looks like you're trying to connect to a newstyle server with the oldstyle protocol. Try the -N option.");
 295                 }
 296                 printf(".");
 297         }
 298
 299         if (read(sock, &size64, sizeof(size64)) <= 0) {
 300                 if (!errno)
 301                         err("Server closed connection");
 302                 err("Failed/3: %m\n");
 303         }
 304         size64 = ntohll(size64);
 305
 306         if ((size64>>12) > (uint64_t)~0UL) {
 307                 printf("size = %luMB", (unsigned long)(size64>>20));
 308                 err("Exported device is too big for me. Get 64-bit machine :-(\n");
 309         } else
 310                 printf("size = %luMB", (unsigned long)(size64>>20));
 311
 312         if(!name) {
 313                 if (read(sock, flags, sizeof(*flags)) < 0)
 314                         err("Failed/4: %m\n");
 315                 *flags = ntohl(*flags);
 316         } else {
 317                 if(read(sock, &tmp, sizeof(tmp)) < 0)
 318                         err("Failed/4: %m\n");
 319                 *flags |= (uint32_t)ntohs(tmp);
 320         }
 321
 322         if (read(sock, &buf, 124) < 0)
 323                 err("Failed/5: %m\n");
 324         printf("\n");
 325
 326         *rsize64 = size64;
 327 }
 328
 329 void setsizes(int nbd, u64 size64, int blocksize, u32 flags) {
 330         unsigned long size;
 331         int read_only = (flags & NBD_FLAG_READ_ONLY) ? 1 : 0;
 332
 333         if (size64>>12 > (uint64_t)~0UL)
 334                 err("Device too large.\n");
 335         else {
 336                 if (ioctl(nbd, NBD_SET_BLKSIZE, 4096UL) < 0)
 337                         err("Ioctl/1.1a failed: %m\n");
 338                 size = (unsigned long)(size64>>12);
 339                 if (ioctl(nbd, NBD_SET_SIZE_BLOCKS, size) < 0)
 340                         err("Ioctl/1.1b failed: %m\n");
 341                 if (ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long)blocksize) < 0)
 342                         err("Ioctl/1.1c failed: %m\n");
 343                 fprintf(stderr, "bs=%d, sz=%llu bytes\n", blocksize, 4096ULL*size);
 344         }
 345
 346         ioctl(nbd, NBD_CLEAR_SOCK);
 347
 348         /* ignore error as kernel may not support */
 349         ioctl(nbd, NBD_SET_FLAGS, (unsigned long) flags);
 350
 351         if (ioctl(nbd, BLKROSET, (unsigned long) &read_only) < 0)
 352                 err("Unable to set read-only attribute for device");
 353 }
 354
 355 void set_timeout(int nbd, int timeout) {
 356         if (timeout) {
 357                 if (ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long)timeout) < 0)
 358                         err("Ioctl NBD_SET_TIMEOUT failed: %m\n");
 359                 fprintf(stderr, "timeout=%d\n", timeout);
 360         }
 361 }
 362
 363 void finish_sock(int sock, int nbd, int swap) {
 364         if (ioctl(nbd, NBD_SET_SOCK, sock) < 0)
 365                 err("Ioctl NBD_SET_SOCK failed: %m\n");
 366
 367         if (swap)
 368                 mlockall(MCL_CURRENT | MCL_FUTURE);
 369 }
 370
 371 static int
 372 oom_adjust(const char *file, const char *value)
 373 {
 374         int fd, rc;
 375         size_t len;
 376
 377         fd = open(file, O_WRONLY);
 378         if (fd < 0)
 379                 return -1;
 380         len = strlen(value);
 381         rc = write(fd, value, len) != (ssize_t) len;
 382         close(fd);
 383         return rc ? -1 : 0;
 384 }
 385
 386 void usage(char* errmsg, ...) {
 387         if(errmsg) {
 388                 char tmp[256];
 389                 va_list ap;
 390                 va_start(ap, errmsg);
 391                 snprintf(tmp, 256, "ERROR: %s\n\n", errmsg);
 392                 vfprintf(stderr, tmp, ap);
 393                 va_end(ap);
 394         } else {
 395                 fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
 396         }
 397         fprintf(stderr, "Usage: nbd-client host port nbd_device [-block-size|-b block size] [-timeout|-t timeout] [-swap|-s] [-sdp|-S] [-persist|-p] [-nofork|-n]\n");
 398         fprintf(stderr, "Or   : nbd-client -name|-N name host [port] nbd_device [-block-size|-b block size] [-timeout|-t timeout] [-swap|-s] [-sdp|-S] [-persist|-p] [-nofork|-n]\n");
 399         fprintf(stderr, "Or   : nbd-client -d nbd_device\n");
 400         fprintf(stderr, "Or   : nbd-client -c nbd_device\n");
 401         fprintf(stderr, "Or   : nbd-client -h|--help\n");
 402         fprintf(stderr, "Or   : nbd-client -l|--list host\n");
 403         fprintf(stderr, "Default value for blocksize is 1024 (recommended for ethernet)\n");
 404         fprintf(stderr, "Allowed values for blocksize are 512,1024,2048,4096\n"); /* will be checked in kernel :) */
 405         fprintf(stderr, "Note, that kernel 2.4.2 and older ones do not work correctly with\n");
 406         fprintf(stderr, "blocksizes other than 1024 without patches\n");
 407         fprintf(stderr, "Default value for port with -N is 10809. Note that port must always be numeric\n");
 408 }
 409
 410 void disconnect(char* device) {
 411         int nbd = open(device, O_RDWR);
 412
 413         if (nbd < 0)
 414                 err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
 415         printf("disconnect, ");
 416         if (ioctl(nbd, NBD_DISCONNECT)<0)
 417                 err("Ioctl failed: %m\n");
 418         printf("sock, ");
 419         if (ioctl(nbd, NBD_CLEAR_SOCK)<0)
 420                 err("Ioctl failed: %m\n");
 421         printf("done\n");
 422 }
 423
 424 int main(int argc, char *argv[]) {
 425         char* port=NULL;
 426         int sock, nbd;
 427         int blocksize=1024;
 428         char *hostname=NULL;
 429         char *nbddev=NULL;
 430         int swap=0;
 431         int cont=0;
 432         int timeout=0;
 433         int sdp=0;
 434         int G_GNUC_UNUSED nofork=0; // if -dNOFORK
 435         u64 size64;
 436         u32 flags;
 437         int c;
 438         int nonspecial=0;
 439         char* name=NULL;
 440         uint32_t needed_flags=0;
 441         uint32_t cflags=0;
 442         uint32_t opts=0;
 443         sigset_t block, old;
 444         struct sigaction sa;
 445         struct option long_options[] = {
 446                 { "block-size", required_argument, NULL, 'b' },
 447                 { "check", required_argument, NULL, 'c' },
 448                 { "disconnect", required_argument, NULL, 'd' },
 449                 { "help", no_argument, NULL, 'h' },
 450                 { "list", no_argument, NULL, 'l' },
 451                 { "name", required_argument, NULL, 'N' },
 452                 { "nofork", no_argument, NULL, 'n' },
 453                 { "persist", no_argument, NULL, 'p' },
 454                 { "sdp", no_argument, NULL, 'S' },
 455                 { "swap", no_argument, NULL, 's' },
 456                 { "timeout", required_argument, NULL, 't' },
 457                 { 0, 0, 0, 0 },
 458         };
 459
 460         logging();
 461
 462         while((c=getopt_long_only(argc, argv, "-b:c:d:hlnN:pSst:", long_options, NULL))>=0) {
 463                 switch(c) {
 464                 case 1:
 465                         // non-option argument
 466                         if(strchr(optarg, '=')) {
 467                                 // old-style 'bs=' or 'timeout='
 468                                 // argument
 469                                 fprintf(stderr, "WARNING: old-style command-line argument encountered. This is deprecated.\n");
 470                                 if(!strncmp(optarg, "bs=", 3)) {
 471                                         optarg+=3;
 472                                         goto blocksize;
 473                                 }
 474                                 if(!strncmp(optarg, "timeout=", 8)) {
 475                                         optarg+=8;
 476                                         goto timeout;
 477                                 }
 478                                 usage("unknown option %s encountered", optarg);
 479                                 exit(EXIT_FAILURE);
 480                         }
 481                         switch(nonspecial++) {
 482                                 case 0:
 483                                         // host
 484                                         hostname=optarg;
 485                                         break;
 486                                 case 1:
 487                                         // port
 488                                         if(!strtol(optarg, NULL, 0)) {
 489                                                 // not parseable as a number, assume it's the device and we have a name
 490                                                 nbddev = optarg;
 491                                                 nonspecial++;
 492                                         } else {
 493                                                 port = optarg;
 494                                         }
 495                                         break;
 496                                 case 2:
 497                                         // device
 498                                         nbddev = optarg;
 499                                         break;
 500                                 default:
 501                                         usage("too many non-option arguments specified");
 502                                         exit(EXIT_FAILURE);
 503                         }
 504                         break;
 505                 case 'b':
 506                       blocksize:
 507                         blocksize=(int)strtol(optarg, NULL, 0);
 508                         break;
 509                 case 'c':
 510                         return check_conn(optarg, 1);
 511                 case 'd':
 512                         disconnect(optarg);
 513                         exit(EXIT_SUCCESS);
 514                 case 'h':
 515                         usage(NULL);
 516                         exit(EXIT_SUCCESS);
 517                 case 'l':
 518                         needed_flags |= NBD_FLAG_FIXED_NEWSTYLE;
 519                         cflags |= NBD_FLAG_C_FIXED_NEWSTYLE;
 520                         opts |= NBDC_DO_LIST;
 521                         name="";
 522                         nbddev="";
 523                         port = NBD_DEFAULT_PORT;
 524                         break;
 525                 case 'n':
 526                         nofork=1;
 527                         break;
 528                 case 'N':
 529                         name=optarg;
 530                         if(!port) {
 531                                 port = NBD_DEFAULT_PORT;
 532                         }
 533                         break;
 534                 case 'p':
 535                         cont=1;
 536                         break;
 537                 case 's':
 538                         swap=1;
 539                         break;
 540                 case 'S':
 541                         sdp=1;
 542                         break;
 543                 case 't':
 544                       timeout:
 545                         timeout=strtol(optarg, NULL, 0);
 546                         break;
 547                 default:
 548                         fprintf(stderr, "E: option eaten by 42 mice\n");
 549                         exit(EXIT_FAILURE);
 550                 }
 551         }
 552
 553         if((!port && !name) || !hostname || !nbddev) {
 554                 usage("not enough information specified");
 555                 exit(EXIT_FAILURE);
 556         }
 557
 558         sock = opennet(hostname, port, sdp);
 559         if (sock < 0)
 560                 exit(EXIT_FAILURE);
 561
 562         negotiate(sock, &size64, &flags, name, needed_flags, cflags, opts);
 563
 564         nbd = open(nbddev, O_RDWR);
 565         if (nbd < 0)
 566           err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
 567
 568         setsizes(nbd, size64, blocksize, flags);
 569         set_timeout(nbd, timeout);
 570         finish_sock(sock, nbd, swap);
 571         if (swap) {
 572                 /* try linux >= 2.6.36 interface first */
 573                 if (oom_adjust("/proc/self/oom_score_adj", "-1000")) {
 574                         /* fall back to linux <= 2.6.35 interface */
 575                         oom_adjust("/proc/self/oom_adj", "-17");
 576                 }
 577         }
 578
 579         /* Go daemon */
 580
 581 #ifndef NOFORK
 582         if(!nofork) {
 583                 if (daemon(0,0) < 0)
 584                         err("Cannot detach from terminal");
 585         }
 586
 587         memset(&sa, 0, sizeof(sa));
 588         sa.sa_handler = SIG_IGN;
 589         sigaction(SIGCHLD, &sa, NULL);
 590 #endif
 591         do {
 592 #ifndef NOFORK
 593
 594                 sigfillset(&block);
 595                 sigdelset(&block, SIGKILL);
 596                 sigdelset(&block, SIGTERM);
 597                 sigdelset(&block, SIGPIPE);
 598                 sigprocmask(SIG_SETMASK, &block, &old);
 599
 600                 if (!fork()) {
 601                         /* Due to a race, the kernel NBD driver cannot
 602                          * call for a reread of the partition table
 603                          * in the handling of the NBD_DO_IT ioctl().
 604                          * Therefore, this is done in the first open()
 605                          * of the device. We therefore make sure that
 606                          * the device is opened at least once after the
 607                          * connection was made. This has to be done in a
 608                          * separate process, since the NBD_DO_IT ioctl()
 609                          * does not return until the NBD device has
 610                          * disconnected.
 611                          */
 612                         while(check_conn(nbddev, 0)) {
 613                                 sleep(1);
 614                         }
 615                         open(nbddev, O_RDONLY);
 616                         exit(0);
 617                 }
 618 #endif
 619
 620                 if (ioctl(nbd, NBD_DO_IT) < 0) {
 621                         int error = errno;
 622                         fprintf(stderr, "nbd,%d: Kernel call returned: %d", getpid(), error);
 623                         if(error==EBADR) {
 624                                 /* The user probably did 'nbd-client -d' on us.
 625                                  * quit */
 626                                 cont=0;
 627                         } else {
 628                                 if(cont) {
 629                                         u64 new_size;
 630                                         u32 new_flags;
 631
 632                                         close(sock); close(nbd);
 633                                         for (;;) {
 634                                                 fprintf(stderr, " Reconnecting\n");
 635                                                 sock = opennet(hostname, port, sdp);
 636                                                 if (sock >= 0)
 637                                                         break;
 638                                                 sleep (1);
 639                                         }
 640                                         nbd = open(nbddev, O_RDWR);
 641                                         if (nbd < 0)
 642                                                 err("Cannot open NBD: %m");
 643                                         negotiate(sock, &new_size, &new_flags, name, needed_flags, cflags, opts);
 644                                         if (size64 != new_size) {
 645                                                 err("Size of the device changed. Bye");
 646                                         }
 647                                         setsizes(nbd, size64, blocksize,
 648                                                                 new_flags);
 649
 650                                         set_timeout(nbd, timeout);
 651                                         finish_sock(sock,nbd,swap);
 652                                 }
 653                         }
 654                 } else {
 655                         /* We're on 2.4. It's not clearly defined what exactly
 656                          * happened at this point. Probably best to quit, now
 657                          */
 658                         fprintf(stderr, "Kernel call returned.");
 659                         cont=0;
 660                 }
 661         } while(cont);
 662         printf("sock, ");
 663         ioctl(nbd, NBD_CLEAR_SOCK);
 664         printf("done\n");
 665         return 0;
 666 }