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 <stdio.h>
  32 #include <fcntl.h>
  33 #include <syslog.h>
  34 #include <stdlib.h>
  35 #include <sys/mount.h>
  36 #include <sys/mman.h>
  37 #include <errno.h>
  38 #include <getopt.h>
  39 #include <stdarg.h>
  40
  41 #include <linux/ioctl.h>
  42 #define MY_NAME "nbd_client"
  43 #include "cliserv.h"
  44
  45 #ifdef WITH_SDP
  46 #include <sdp_inet.h>
  47 #endif
  48
  49 int check_conn(char* devname, int do_print) {
  50         char buf[256];
  51         char* p;
  52         int fd;
  53         int len;
  54
  55         if(!strncmp(devname, "/dev/", 5)) {
  56                 devname+=5;
  57         }
  58         if((p=strchr(devname, 'p'))) {
  59                 /* We can't do checks on partitions. */
  60                 *p='\0';
  61         }
  62         snprintf(buf, 256, "/sys/block/%s/pid", devname);
  63         if((fd=open(buf, O_RDONLY))<0) {
  64                 if(errno==ENOENT) {
  65                         return 1;
  66                 } else {
  67                         return 2;
  68                 }
  69         }
  70         len=read(fd, buf, 256);
  71         buf[len-1]='\0';
  72         if(do_print) printf("%s\n", buf);
  73         return 0;
  74 }
  75
  76 int opennet(char *name, char* portstr, int sdp) {
  77         int sock;
  78         struct addrinfo hints;
  79         struct addrinfo *ai = NULL;
  80         struct addrinfo *rp = NULL;
  81         int e;
  82
  83         memset(&hints,'\0',sizeof(hints));
  84         hints.ai_family = AF_UNSPEC;
  85         hints.ai_socktype = SOCK_STREAM;
  86         hints.ai_flags = AI_ADDRCONFIG | AI_NUMERICSERV;
  87         hints.ai_protocol = IPPROTO_TCP;
  88
  89         e = getaddrinfo(name, portstr, &hints, &ai);
  90
  91         if(e != 0) {
  92                 fprintf(stderr, "getaddrinfo failed: %s\n", gai_strerror(e));
  93                 freeaddrinfo(ai);
  94                 exit(EXIT_FAILURE);
  95         }
  96
  97         if(sdp) {
  98 #ifdef WITH_SDP
  99                 if (ai->ai_family == AF_INET)
 100                         ai->ai_family = AF_INET_SDP;
 101                 else (ai->ai_family == AF_INET6)
 102                         ai->ai_family = AF_INET6_SDP;
 103 #else
 104                 err("Can't do SDP: I was not compiled with SDP support!");
 105 #endif
 106         }
 107
 108         for(rp = ai; rp != NULL; rp = rp->ai_next) {
 109                 sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 110
 111                 if(sock == -1)
 112                         continue;       /* error */
 113
 114                 if(connect(sock, rp->ai_addr, rp->ai_addrlen) != -1)
 115                         break;          /* success */
 116         }
 117
 118         if (rp == NULL)
 119                 err("Socket failed: %m");
 120
 121         setmysockopt(sock);
 122
 123         freeaddrinfo(ai);
 124         return sock;
 125 }
 126
 127 void negotiate(int sock, u64 *rsize64, u32 *flags, char* name) {
 128         u64 magic, size64;
 129         uint16_t tmp;
 130         char buf[256] = "\0\0\0\0\0\0\0\0\0";
 131
 132         printf("Negotiation: ");
 133         if (read(sock, buf, 8) < 0)
 134                 err("Failed/1: %m");
 135         if (strlen(buf)==0)
 136                 err("Server closed connection");
 137         if (strcmp(buf, INIT_PASSWD))
 138                 err("INIT_PASSWD bad");
 139         printf(".");
 140         if (read(sock, &magic, sizeof(magic)) < 0)
 141                 err("Failed/2: %m");
 142         magic = ntohll(magic);
 143         if(name) {
 144                 uint32_t opt;
 145                 uint32_t namesize;
 146                 uint32_t reserved = 0;
 147
 148                 if (magic != opts_magic)
 149                         err("Not enough opts_magic");
 150                 printf(".");
 151                 if(read(sock, &tmp, sizeof(uint16_t)) < 0) {
 152                         err("Failed reading flags: %m");
 153                 }
 154                 *flags = ((u32)ntohs(tmp));
 155
 156                 /* reserved for future use*/
 157                 if (write(sock, &reserved, sizeof(reserved)) < 0)
 158                         err("Failed/2.1: %m");
 159
 160                 /* Write the export name that we're after */
 161                 magic = ntohll(opts_magic);
 162                 if (write(sock, &magic, sizeof(magic)) < 0)
 163                         err("Failed/2.2: %m");
 164                 opt = ntohl(NBD_OPT_EXPORT_NAME);
 165                 if (write(sock, &opt, sizeof(opt)) < 0)
 166                         err("Failed/2.3: %m");
 167                 namesize = (u32)strlen(name);
 168                 namesize = ntohl(namesize);
 169                 if (write(sock, &namesize, sizeof(namesize)) < 0)
 170                         err("Failed/2.4: %m");
 171                 if (write(sock, name, strlen(name)) < 0)
 172                         err("Failed/2.4: %m");
 173         } else {
 174                 if (magic != cliserv_magic)
 175                         err("Not enough cliserv_magic");
 176                 printf(".");
 177         }
 178
 179         if (read(sock, &size64, sizeof(size64)) < 0)
 180                 err("Failed/3: %m\n");
 181         size64 = ntohll(size64);
 182
 183 #ifdef NBD_SET_SIZE_BLOCKS
 184         if ((size64>>12) > (uint64_t)~0UL) {
 185                 printf("size = %luMB", (unsigned long)(size64>>20));
 186                 err("Exported device is too big for me. Get 64-bit machine :-(\n");
 187         } else
 188                 printf("size = %luMB", (unsigned long)(size64>>20));
 189 #else
 190         if (size64 > (~0UL >> 1)) {
 191                 printf("size = %luKB", (unsigned long)(size64>>10));
 192                 err("Exported device is too big. Get 64-bit machine or newer kernel :-(\n");
 193         } else
 194                 printf("size = %lu", (unsigned long)(size64));
 195 #endif
 196
 197         if(!name) {
 198                 if (read(sock, flags, sizeof(*flags)) < 0)
 199                         err("Failed/4: %m\n");
 200                 *flags = ntohl(*flags);
 201         } else {
 202                 if(read(sock, &tmp, sizeof(tmp)) < 0)
 203                         err("Failed/4: %m\n");
 204                 *flags |= (uint32_t)ntohs(tmp);
 205         }
 206
 207         if (read(sock, &buf, 124) < 0)
 208                 err("Failed/5: %m\n");
 209         printf("\n");
 210
 211         *rsize64 = size64;
 212 }
 213
 214 void setsizes(int nbd, u64 size64, int blocksize, u32 flags) {
 215         unsigned long size;
 216         int read_only = (flags & NBD_FLAG_READ_ONLY) ? 1 : 0;
 217
 218 #ifdef NBD_SET_SIZE_BLOCKS
 219         if (size64>>12 > (uint64_t)~0UL)
 220                 err("Device too large.\n");
 221         else {
 222                 if (ioctl(nbd, NBD_SET_BLKSIZE, 4096UL) < 0)
 223                         err("Ioctl/1.1a failed: %m\n");
 224                 size = (unsigned long)(size64>>12);
 225                 if (ioctl(nbd, NBD_SET_SIZE_BLOCKS, size) < 0)
 226                         err("Ioctl/1.1b failed: %m\n");
 227                 if (ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long)blocksize) < 0)
 228                         err("Ioctl/1.1c failed: %m\n");
 229                 fprintf(stderr, "bs=%d, sz=%llu bytes\n", blocksize, 4096ULL*size);
 230         }
 231 #else
 232         if (size64 > (~0UL >> 1)) {
 233                 err("Device too large.\n");
 234         } else {
 235                 size = (unsigned long)size64;
 236                 if (ioctl(nbd, NBD_SET_SIZE, size) < 0)
 237                         err("Ioctl NBD_SET_SIZE failed: %m\n");
 238         }
 239 #endif
 240
 241         ioctl(nbd, NBD_CLEAR_SOCK);
 242
 243         /* ignore error as kernel may not support */
 244         ioctl(nbd, NBD_SET_FLAGS, (unsigned long) flags);
 245
 246         if (ioctl(nbd, BLKROSET, (unsigned long) &read_only) < 0)
 247                 err("Unable to set read-only attribute for device");
 248 }
 249
 250 void set_timeout(int nbd, int timeout) {
 251         if (timeout) {
 252 #ifdef NBD_SET_TIMEOUT
 253                 if (ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long)timeout) < 0)
 254                         err("Ioctl NBD_SET_TIMEOUT failed: %m\n");
 255                 fprintf(stderr, "timeout=%d\n", timeout);
 256 #else
 257                 err("Ioctl NBD_SET_TIMEOUT cannot be called when compiled on a system that does not support it\n");
 258 #endif
 259         }
 260 }
 261
 262 void finish_sock(int sock, int nbd, int swap) {
 263         if (ioctl(nbd, NBD_SET_SOCK, sock) < 0)
 264                 err("Ioctl NBD_SET_SOCK failed: %m\n");
 265
 266         if (swap)
 267                 mlockall(MCL_CURRENT | MCL_FUTURE);
 268 }
 269
 270 void usage(char* errmsg, ...) {
 271         if(errmsg) {
 272                 char tmp[256];
 273                 va_list ap;
 274                 va_start(ap, errmsg);
 275                 snprintf(tmp, 256, "ERROR: %s\n\n", errmsg);
 276                 vfprintf(stderr, errmsg, ap);
 277                 va_end(ap);
 278         } else {
 279                 fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
 280         }
 281         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");
 282         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");
 283         fprintf(stderr, "Or   : nbd-client -d nbd_device\n");
 284         fprintf(stderr, "Or   : nbd-client -c nbd_device\n");
 285         fprintf(stderr, "Or   : nbd-client -h|--help\n");
 286         fprintf(stderr, "Default value for blocksize is 1024 (recommended for ethernet)\n");
 287         fprintf(stderr, "Allowed values for blocksize are 512,1024,2048,4096\n"); /* will be checked in kernel :) */
 288         fprintf(stderr, "Note, that kernel 2.4.2 and older ones do not work correctly with\n");
 289         fprintf(stderr, "blocksizes other than 1024 without patches\n");
 290         fprintf(stderr, "Default value for port with -N is 10809. Note that port must always be numeric\n");
 291 }
 292
 293 void disconnect(char* device) {
 294         int nbd = open(device, O_RDWR);
 295
 296         if (nbd < 0)
 297                 err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
 298         printf("Disconnecting: que, ");
 299         if (ioctl(nbd, NBD_CLEAR_QUE)< 0)
 300                 err("Ioctl failed: %m\n");
 301         printf("disconnect, ");
 302 #ifdef NBD_DISCONNECT
 303         if (ioctl(nbd, NBD_DISCONNECT)<0)
 304                 err("Ioctl failed: %m\n");
 305         printf("sock, ");
 306 #else
 307         fprintf(stderr, "Can't disconnect: I was not compiled with disconnect support!\n" );
 308         exit(1);
 309 #endif
 310         if (ioctl(nbd, NBD_CLEAR_SOCK)<0)
 311                 err("Ioctl failed: %m\n");
 312         printf("done\n");
 313 }
 314
 315 int main(int argc, char *argv[]) {
 316         char* port=NULL;
 317         int sock, nbd;
 318         int blocksize=1024;
 319         char *hostname=NULL;
 320         char *nbddev=NULL;
 321         int swap=0;
 322         int cont=0;
 323         int timeout=0;
 324         int sdp=0;
 325         int G_GNUC_UNUSED nofork=0; // if -dNOFORK
 326         u64 size64;
 327         u32 flags;
 328         int c;
 329         int nonspecial=0;
 330         char* name=NULL;
 331         struct option long_options[] = {
 332                 { "block-size", required_argument, NULL, 'b' },
 333                 { "check", required_argument, NULL, 'c' },
 334                 { "disconnect", required_argument, NULL, 'd' },
 335                 { "help", no_argument, NULL, 'h' },
 336                 { "name", required_argument, NULL, 'N' },
 337                 { "nofork", no_argument, NULL, 'n' },
 338                 { "persist", no_argument, NULL, 'p' },
 339                 { "sdp", no_argument, NULL, 'S' },
 340                 { "swap", no_argument, NULL, 's' },
 341                 { "timeout", required_argument, NULL, 't' },
 342                 { 0, 0, 0, 0 },
 343         };
 344
 345         logging();
 346
 347         while((c=getopt_long_only(argc, argv, "-b:c:d:hnN:pSst:", long_options, NULL))>=0) {
 348                 switch(c) {
 349                 case 1:
 350                         // non-option argument
 351                         if(strchr(optarg, '=')) {
 352                                 // old-style 'bs=' or 'timeout='
 353                                 // argument
 354                                 fprintf(stderr, "WARNING: old-style command-line argument encountered. This is deprecated.\n");
 355                                 if(!strncmp(optarg, "bs=", 3)) {
 356                                         optarg+=3;
 357                                         goto blocksize;
 358                                 }
 359                                 if(!strncmp(optarg, "timeout=", 8)) {
 360                                         optarg+=8;
 361                                         goto timeout;
 362                                 }
 363                                 usage("unknown option %s encountered", optarg);
 364                                 exit(EXIT_FAILURE);
 365                         }
 366                         switch(nonspecial++) {
 367                                 case 0:
 368                                         // host
 369                                         hostname=optarg;
 370                                         break;
 371                                 case 1:
 372                                         // port
 373                                         if(!strtol(optarg, NULL, 0)) {
 374                                                 // not parseable as a number, assume it's the device and we have a name
 375                                                 nbddev = optarg;
 376                                                 nonspecial++;
 377                                         } else {
 378                                                 port = optarg;
 379                                         }
 380                                         break;
 381                                 case 2:
 382                                         // device
 383                                         nbddev = optarg;
 384                                         break;
 385                                 default:
 386                                         usage("too many non-option arguments specified");
 387                                         exit(EXIT_FAILURE);
 388                         }
 389                         break;
 390                 case 'b':
 391                       blocksize:
 392                         blocksize=(int)strtol(optarg, NULL, 0);
 393                         break;
 394                 case 'c':
 395                         return check_conn(optarg, 1);
 396                 case 'd':
 397                         disconnect(optarg);
 398                         exit(EXIT_SUCCESS);
 399                 case 'h':
 400                         usage(NULL);
 401                         exit(EXIT_SUCCESS);
 402                 case 'n':
 403                         nofork=1;
 404                         break;
 405                 case 'N':
 406                         name=optarg;
 407                         if(!port) {
 408                                 port = NBD_DEFAULT_PORT;
 409                         }
 410                         break;
 411                 case 'p':
 412                         cont=1;
 413                         break;
 414                 case 's':
 415                         swap=1;
 416                         break;
 417                 case 'S':
 418                         sdp=1;
 419                         break;
 420                 case 't':
 421                       timeout:
 422                         timeout=strtol(optarg, NULL, 0);
 423                         break;
 424                 default:
 425                         fprintf(stderr, "E: option eaten by 42 mice\n");
 426                         exit(EXIT_FAILURE);
 427                 }
 428         }
 429
 430         if((!port && !name) || !hostname || !nbddev) {
 431                 usage("not enough information specified");
 432                 exit(EXIT_FAILURE);
 433         }
 434
 435         nbd = open(nbddev, O_RDWR);
 436         if (nbd < 0)
 437           err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
 438
 439         sock = opennet(hostname, port, sdp);
 440
 441         negotiate(sock, &size64, &flags, name);
 442         setsizes(nbd, size64, blocksize, flags);
 443         set_timeout(nbd, timeout);
 444         finish_sock(sock, nbd, swap);
 445
 446         /* Go daemon */
 447
 448 #ifndef NOFORK
 449         if(!nofork) {
 450                 if (daemon(0,0) < 0)
 451                         err("Cannot detach from terminal");
 452         }
 453 #endif
 454         do {
 455 #ifndef NOFORK
 456                 if (fork()) {
 457                         /* Due to a race, the kernel NBD driver cannot
 458                          * call for a reread of the partition table
 459                          * in the handling of the NBD_DO_IT ioctl().
 460                          * Therefore, this is done in the first open()
 461                          * of the device. We therefore make sure that
 462                          * the device is opened at least once after the
 463                          * connection was made. This has to be done in a
 464                          * separate process, since the NBD_DO_IT ioctl()
 465                          * does not return until the NBD device has
 466                          * disconnected.
 467                          */
 468                         while(check_conn(nbddev, 0)) {
 469                                 sleep(1);
 470                         }
 471                         open(nbddev, O_RDONLY);
 472                         exit(0);
 473                 }
 474 #endif
 475
 476                 if (ioctl(nbd, NBD_DO_IT) < 0) {
 477                         fprintf(stderr, "Kernel call returned: %m");
 478                         if(errno==EBADR) {
 479                                 /* The user probably did 'nbd-client -d' on us.
 480                                  * quit */
 481                                 cont=0;
 482                         } else {
 483                                 if(cont) {
 484                                         u64 new_size;
 485                                         u32 new_flags;
 486
 487                                         fprintf(stderr, " Reconnecting\n");
 488                                         close(sock); close(nbd);
 489                                         sock = opennet(hostname, port, sdp);
 490                                         nbd = open(nbddev, O_RDWR);
 491                                         negotiate(sock, &new_size, &new_flags, name);
 492                                         if (size64 != new_size) {
 493                                                 err("Size of the device changed. Bye");
 494                                         }
 495                                         setsizes(nbd, size64, blocksize,
 496                                                                 new_flags);
 497
 498                                         set_timeout(nbd, timeout);
 499                                         finish_sock(sock,nbd,swap);
 500                                 }
 501                         }
 502                 } else {
 503                         /* We're on 2.4. It's not clearly defined what exactly
 504                          * happened at this point. Probably best to quit, now
 505                          */
 506                         fprintf(stderr, "Kernel call returned.");
 507                         cont=0;
 508                 }
 509         } while(cont);
 510         printf("Closing: que, ");
 511         ioctl(nbd, NBD_CLEAR_QUE);
 512         printf("sock, ");
 513         ioctl(nbd, NBD_CLEAR_SOCK);
 514         printf("done\n");
 515         return 0;
 516 }