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  *
   7  * Version 1.0 - 64bit issues should be fixed, now
   8  * Version 1.1 - added bs (blocksize) option (Alexey Guzeev, aga@permonline.ru)
   9  * Version 1.2 - I added new option '-d' to send the disconnect request
  10  * Version 2.0 - Version synchronised with server
  11  * Version 2.1 - Check for disconnection before INIT_PASSWD is received
  12  *      to make errormsg a bit more helpful in case the server can't
  13  *      open the exported file.
  14  * 16/03/2010 - Add IPv6 support.
  15  *      Kitt Tientanopajai <kitt@kitty.in.th>
  16  *      Neutron Soutmun <neo.neutron@gmail.com>
  17  *      Suriya Soutmun <darksolar@gmail.com>
  18  */
  19
  20 #include "config.h"
  21 #include "lfs.h"
  22
  23 #include <sys/ioctl.h>
  24 #include <sys/socket.h>
  25 #include <sys/types.h>
  26 #include <unistd.h>
  27 #include <netinet/tcp.h>
  28 #include <netinet/in.h>
  29 #include <netdb.h>
  30 #include <stdio.h>
  31 #include <fcntl.h>
  32 #include <syslog.h>
  33 #include <stdlib.h>
  34 #include <sys/mount.h>
  35 #include <sys/mman.h>
  36 #include <errno.h>
  37 #include <getopt.h>
  38 #include <stdarg.h>
  39
  40 #ifndef __GNUC__
  41 #error I need GCC to work
  42 #endif
  43
  44 #include <linux/ioctl.h>
  45 #define MY_NAME "nbd_client"
  46 #include "cliserv.h"
  47
  48 int check_conn(char* devname, int do_print) {
  49         char buf[256];
  50         char* p;
  51         int fd;
  52         int len;
  53
  54         if(!strncmp(devname, "/dev/", 5)) {
  55                 devname+=5;
  56         }
  57         if((p=strchr(devname, 'p'))) {
  58                 /* We can't do checks on partitions. */
  59                 *p='\0';
  60         }
  61         snprintf(buf, 256, "/sys/block/%s/pid", devname);
  62         if((fd=open(buf, O_RDONLY))<0) {
  63                 if(errno==ENOENT) {
  64                         return 1;
  65                 } else {
  66                         return 2;
  67                 }
  68         }
  69         len=read(fd, buf, 256);
  70         buf[len-1]='\0';
  71         if(do_print) printf("%s\n", buf);
  72         return 0;
  73 }
  74
  75 int opennet(char *name, char* portstr, int sdp) {
  76         int sock;
  77         struct addrinfo hints;
  78         struct addrinfo *ai = NULL;
  79         struct addrinfo *rp = NULL;
  80         int e;
  81
  82         memset(&hints,'\0',sizeof(hints));
  83         hints.ai_family = AF_UNSPEC;
  84         hints.ai_socktype = SOCK_STREAM;
  85         hints.ai_flags = AI_ADDRCONFIG | AI_NUMERICSERV;
  86         hints.ai_protocol = IPPROTO_TCP;
  87
  88         e = getaddrinfo(name, portstr, &hints, &ai);
  89
  90         if(e != 0) {
  91                 fprintf(stderr, "getaddrinfo failed: %s\n", gai_strerror(e));
  92                 freeaddrinfo(ai);
  93                 exit(EXIT_FAILURE);
  94         }
  95
  96         if(sdp) {
  97 #ifdef WITH_SDP
  98                 if (ai->ai_family == AF_INET)
  99                         ai->ai_family = AF_INET_SDP;
 100                 else (ai->ai_family == AF_INET6)
 101                         ai->ai_family = AF_INET6_SDP;
 102 #else
 103                 err("Can't do SDP: I was not compiled with SDP support!");
 104 #endif
 105         }
 106
 107         for(rp = ai; rp != NULL; rp = rp->ai_next) {
 108                 sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 109
 110                 if(sock == -1)
 111                         continue;       /* error */
 112
 113                 if(connect(sock, rp->ai_addr, rp->ai_addrlen) != -1)
 114                         break;          /* success */
 115         }
 116
 117         if (rp == NULL)
 118                 err("Socket failed: %m");
 119
 120         setmysockopt(sock);
 121
 122         freeaddrinfo(ai);
 123         return sock;
 124 }
 125
 126 void negotiate(int sock, u64 *rsize64, u32 *flags, char* name) {
 127         u64 magic, size64;
 128         uint16_t tmp;
 129         char buf[256] = "\0\0\0\0\0\0\0\0\0";
 130
 131         printf("Negotiation: ");
 132         if (read(sock, buf, 8) < 0)
 133                 err("Failed/1: %m");
 134         if (strlen(buf)==0)
 135                 err("Server closed connection");
 136         if (strcmp(buf, INIT_PASSWD))
 137                 err("INIT_PASSWD bad");
 138         printf(".");
 139         if (read(sock, &magic, sizeof(magic)) < 0)
 140                 err("Failed/2: %m");
 141         magic = ntohll(magic);
 142         if(name) {
 143                 uint32_t opt;
 144                 uint32_t namesize;
 145                 uint32_t reserved = 0;
 146
 147                 if (magic != opts_magic)
 148                         err("Not enough opts_magic");
 149                 printf(".");
 150                 if(read(sock, &tmp, sizeof(uint16_t)) < 0) {
 151                         err("Failed reading flags: %m");
 152                 }
 153                 *flags = ((u32)ntohs(tmp)) << 16;
 154
 155                 /* reserved for future use*/
 156                 write(sock, &reserved, sizeof(reserved));
 157
 158                 /* Write the export name that we're after */
 159                 magic = ntohll(opts_magic);
 160                 write(sock, &magic, sizeof(magic));
 161                 opt = ntohl(NBD_OPT_EXPORT_NAME);
 162                 write(sock, &opt, sizeof(opt));
 163                 namesize = (u32)strlen(name);
 164                 namesize = ntohl(namesize);
 165                 write(sock, &namesize, sizeof(namesize));
 166                 write(sock, name, strlen(name));
 167         } else {
 168                 if (magic != cliserv_magic)
 169                         err("Not enough cliserv_magic");
 170                 printf(".");
 171         }
 172
 173         if (read(sock, &size64, sizeof(size64)) < 0)
 174                 err("Failed/3: %m\n");
 175         size64 = ntohll(size64);
 176
 177 #ifdef NBD_SET_SIZE_BLOCKS
 178         if ((size64>>10) > (~0UL >> 1)) {
 179                 printf("size = %luMB", (unsigned long)(size64>>20));
 180                 err("Exported device is too big for me. Get 64-bit machine :-(\n");
 181         } else
 182                 printf("size = %luKB", (unsigned long)(size64>>10));
 183 #else
 184         if (size64 > (~0UL >> 1)) {
 185                 printf("size = %luKB", (unsigned long)(size64>>10));
 186                 err("Exported device is too big. Get 64-bit machine or newer kernel :-(\n");
 187         } else
 188                 printf("size = %lu", (unsigned long)(size64));
 189 #endif
 190
 191         if(!name) {
 192                 if (read(sock, flags, sizeof(*flags)) < 0)
 193                         err("Failed/4: %m\n");
 194                 *flags = ntohl(*flags);
 195         } else {
 196                 if(read(sock, &tmp, sizeof(tmp)) < 0)
 197                         err("Failed/4: %m\n");
 198                 *flags |= (uint32_t)ntohs(tmp);
 199         }
 200
 201         if (read(sock, &buf, 124) < 0)
 202                 err("Failed/5: %m\n");
 203         printf("\n");
 204
 205         *rsize64 = size64;
 206 }
 207
 208 void setsizes(int nbd, u64 size64, int blocksize, u32 flags) {
 209         unsigned long size;
 210         int read_only = (flags & NBD_FLAG_READ_ONLY) ? 1 : 0;
 211
 212 #ifdef NBD_SET_SIZE_BLOCKS
 213         if (size64/blocksize > (~0UL >> 1))
 214                 err("Device too large.\n");
 215         else {
 216                 int er;
 217                 if (ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long)blocksize) < 0)
 218                         err("Ioctl/1.1a failed: %m\n");
 219                 size = (unsigned long)(size64/blocksize);
 220                 if ((er = ioctl(nbd, NBD_SET_SIZE_BLOCKS, size)) < 0)
 221                         err("Ioctl/1.1b failed: %m\n");
 222                 fprintf(stderr, "bs=%d, sz=%lu\n", blocksize, size);
 223         }
 224 #else
 225         if (size64 > (~0UL >> 1)) {
 226                 err("Device too large.\n");
 227         } else {
 228                 size = (unsigned long)size64;
 229                 if (ioctl(nbd, NBD_SET_SIZE, size) < 0)
 230                         err("Ioctl NBD_SET_SIZE failed: %m\n");
 231         }
 232 #endif
 233
 234         ioctl(nbd, NBD_CLEAR_SOCK);
 235
 236         if (ioctl(nbd, BLKROSET, (unsigned long) &read_only) < 0)
 237                 err("Unable to set read-only attribute for device");
 238 }
 239
 240 void set_timeout(int nbd, int timeout) {
 241         if (timeout) {
 242 #ifdef NBD_SET_TIMEOUT
 243                 if (ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long)timeout) < 0)
 244                         err("Ioctl NBD_SET_TIMEOUT failed: %m\n");
 245                 fprintf(stderr, "timeout=%d\n", timeout);
 246 #else
 247                 err("Ioctl NBD_SET_TIMEOUT cannot be called when compiled on a system that does not support it\n");
 248 #endif
 249         }
 250 }
 251
 252 void finish_sock(int sock, int nbd, int swap) {
 253         if (ioctl(nbd, NBD_SET_SOCK, sock) < 0)
 254                 err("Ioctl NBD_SET_SOCK failed: %m\n");
 255
 256         if (swap)
 257                 mlockall(MCL_CURRENT | MCL_FUTURE);
 258 }
 259
 260 void usage(char* errmsg, ...) {
 261         if(errmsg) {
 262                 char tmp[256];
 263                 va_list ap;
 264                 va_start(ap, errmsg);
 265                 snprintf(tmp, 256, "ERROR: %s\n\n", errmsg);
 266                 vfprintf(stderr, errmsg, ap);
 267                 va_end(ap);
 268         } else {
 269                 fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
 270         }
 271         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] [-name|-N name]\n");
 272         fprintf(stderr, "Or   : nbd-client -d nbd_device\n");
 273         fprintf(stderr, "Or   : nbd-client -c nbd_device\n");
 274         fprintf(stderr, "Or   : nbd-client -h|--help\n");
 275         fprintf(stderr, "Default value for blocksize is 1024 (recommended for ethernet)\n");
 276         fprintf(stderr, "Allowed values for blocksize are 512,1024,2048,4096\n"); /* will be checked in kernel :) */
 277         fprintf(stderr, "Note, that kernel 2.4.2 and older ones do not work correctly with\n");
 278         fprintf(stderr, "blocksizes other than 1024 without patches\n");
 279 }
 280
 281 void disconnect(char* device) {
 282         int nbd = open(device, O_RDWR);
 283
 284         if (nbd < 0)
 285                 err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
 286         printf("Disconnecting: que, ");
 287         if (ioctl(nbd, NBD_CLEAR_QUE)< 0)
 288                 err("Ioctl failed: %m\n");
 289         printf("disconnect, ");
 290 #ifdef NBD_DISCONNECT
 291         if (ioctl(nbd, NBD_DISCONNECT)<0)
 292                 err("Ioctl failed: %m\n");
 293         printf("sock, ");
 294 #else
 295         fprintf(stderr, "Can't disconnect: I was not compiled with disconnect support!\n" );
 296         exit(1);
 297 #endif
 298         if (ioctl(nbd, NBD_CLEAR_SOCK)<0)
 299                 err("Ioctl failed: %m\n");
 300         printf("done\n");
 301 }
 302
 303 int main(int argc, char *argv[]) {
 304         char* port=NULL;
 305         int sock, nbd;
 306         int blocksize=1024;
 307         char *hostname=NULL;
 308         char *nbddev=NULL;
 309         int swap=0;
 310         int cont=0;
 311         int timeout=0;
 312         int sdp=0;
 313         int nofork=0;
 314         u64 size64;
 315         u32 flags;
 316         int c;
 317         int nonspecial=0;
 318         char* name=NULL;
 319         struct option long_options[] = {
 320                 { "block-size", required_argument, NULL, 'b' },
 321                 { "check", required_argument, NULL, 'c' },
 322                 { "disconnect", required_argument, NULL, 'd' },
 323                 { "help", no_argument, NULL, 'h' },
 324                 { "name", required_argument, NULL, 'N' },
 325                 { "nofork", no_argument, NULL, 'n' },
 326                 { "persist", no_argument, NULL, 'p' },
 327                 { "sdp", no_argument, NULL, 'S' },
 328                 { "swap", no_argument, NULL, 's' },
 329                 { "timeout", required_argument, NULL, 't' },
 330                 { 0, 0, 0, 0 },
 331         };
 332
 333         logging();
 334
 335         while((c=getopt_long_only(argc, argv, "-b:c:d:hnN:pSst:", long_options, NULL))>=0) {
 336                 switch(c) {
 337                 case 1:
 338                         // non-option argument
 339                         if(strchr(optarg, '=')) {
 340                                 // old-style 'bs=' or 'timeout='
 341                                 // argument
 342                                 fprintf(stderr, "WARNING: old-style command-line argument encountered. This is deprecated.\n");
 343                                 if(!strncmp(optarg, "bs=", 3)) {
 344                                         optarg+=3;
 345                                         goto blocksize;
 346                                 }
 347                                 if(!strncmp(optarg, "timeout=", 8)) {
 348                                         optarg+=8;
 349                                         goto timeout;
 350                                 }
 351                                 usage("unknown option %s encountered", optarg);
 352                                 exit(EXIT_FAILURE);
 353                         }
 354                         switch(nonspecial++) {
 355                                 case 0:
 356                                         // host
 357                                         hostname=optarg;
 358                                         break;
 359                                 case 1:
 360                                         // port
 361                                         if(!strtol(optarg, NULL, 0)) {
 362                                                 // not parseable as a number, assume it's the device and we have a name
 363                                                 nbddev = optarg;
 364                                                 nonspecial++;
 365                                         } else {
 366                                                 port = optarg;
 367                                                 if(name) {
 368                                                         usage("port and name specified at the same time. This is not supported.");
 369                                                         exit(EXIT_FAILURE);
 370                                                 }
 371                                         }
 372                                         break;
 373                                 case 2:
 374                                         // device
 375                                         nbddev = optarg;
 376                                         break;
 377                                 default:
 378                                         usage("too many non-option arguments specified");
 379                                         exit(EXIT_FAILURE);
 380                         }
 381                         break;
 382                 case 'b':
 383                       blocksize:
 384                         blocksize=(int)strtol(optarg, NULL, 0);
 385                         break;
 386                 case 'c':
 387                         return check_conn(optarg, 1);
 388                 case 'd':
 389                         disconnect(optarg);
 390                         exit(EXIT_SUCCESS);
 391                 case 'h':
 392                         usage(NULL);
 393                         exit(EXIT_SUCCESS);
 394                 case 'n':
 395                         nofork=1;
 396                         break;
 397                 case 'N':
 398                         name=optarg;
 399                         if(port) {
 400                                 usage("port and name specified at the same time. This is not supported.");
 401                                 exit(EXIT_FAILURE);
 402                         }
 403                         port = NBD_DEFAULT_PORT;
 404                         break;
 405                 case 'p':
 406                         cont=1;
 407                         break;
 408                 case 's':
 409                         swap=1;
 410                         break;
 411                 case 'S':
 412                         sdp=1;
 413                         break;
 414                 case 't':
 415                       timeout:
 416                         timeout=strtol(optarg, NULL, 0);
 417                         break;
 418                 default:
 419                         fprintf(stderr, "E: option eaten by 42 mice\n");
 420                         exit(EXIT_FAILURE);
 421                 }
 422         }
 423
 424         if((!port && !name) || !hostname || !nbddev) {
 425                 usage("not enough information specified");
 426                 exit(EXIT_FAILURE);
 427         }
 428
 429         nbd = open(nbddev, O_RDWR);
 430         if (nbd < 0)
 431           err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
 432         ++argv; --argc; /* skip device */
 433
 434         sock = opennet(hostname, port, sdp);
 435
 436         negotiate(sock, &size64, &flags, name);
 437         setsizes(nbd, size64, blocksize, flags);
 438         set_timeout(nbd, timeout);
 439         finish_sock(sock, nbd, swap);
 440
 441         /* Go daemon */
 442
 443 #ifndef NOFORK
 444         if(!nofork) daemon(0,0);
 445 #endif
 446         do {
 447 #ifndef NOFORK
 448                 if (fork()) {
 449                         /* Due to a race, the kernel NBD driver cannot
 450                          * call for a reread of the partition table
 451                          * in the handling of the NBD_DO_IT ioctl().
 452                          * Therefore, this is done in the first open()
 453                          * of the device. We therefore make sure that
 454                          * the device is opened at least once after the
 455                          * connection was made. This has to be done in a
 456                          * separate process, since the NBD_DO_IT ioctl()
 457                          * does not return until the NBD device has
 458                          * disconnected.
 459                          */
 460                         while(check_conn(nbddev, 0)) {
 461                                 sleep(1);
 462                         }
 463                         open(nbddev, O_RDONLY);
 464                         exit(0);
 465                 }
 466 #endif
 467
 468                 if (ioctl(nbd, NBD_DO_IT) < 0) {
 469                         fprintf(stderr, "Kernel call returned: %m");
 470                         if(errno==EBADR) {
 471                                 /* The user probably did 'nbd-client -d' on us.
 472                                  * quit */
 473                                 cont=0;
 474                         } else {
 475                                 if(cont) {
 476                                         u64 new_size;
 477                                         u32 new_flags;
 478
 479                                         fprintf(stderr, " Reconnecting\n");
 480                                         close(sock); close(nbd);
 481                                         sock = opennet(hostname, port, sdp);
 482                                         nbd = open(nbddev, O_RDWR);
 483                                         negotiate(sock, &new_size, &new_flags, name);
 484                                         if (size64 != new_size) {
 485                                                 err("Size of the device changed. Bye");
 486                                         }
 487                                         setsizes(nbd, size64, blocksize,
 488                                                                 new_flags);
 489
 490                                         set_timeout(nbd, timeout);
 491                                         finish_sock(sock,nbd,swap);
 492                                 }
 493                         }
 494                 } else {
 495                         /* We're on 2.4. It's not clearly defined what exactly
 496                          * happened at this point. Probably best to quit, now
 497                          */
 498                         fprintf(stderr, "Kernel call returned.");
 499                         cont=0;
 500                 }
 501         } while(cont);
 502         printf("Closing: que, ");
 503         ioctl(nbd, NBD_CLEAR_QUE);
 504         printf("sock, ");
 505         ioctl(nbd, NBD_CLEAR_SOCK);
 506         printf("done\n");
 507         return 0;
 508 }