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