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
  39 #ifndef __GNUC__
  40 #error I need GCC to work
  41 #endif
  42
  43 #include <linux/ioctl.h>
  44 #define MY_NAME "nbd_client"
  45 #include "cliserv.h"
  46
  47 int check_conn(char* devname, int do_print) {
  48         char buf[256];
  49         char* p;
  50         int fd;
  51         int len;
  52         if(!strncmp(devname, "/dev/", 5)) {
  53                 devname+=5;
  54         }
  55         if((p=strchr(devname, 'p'))) {
  56                 /* We can't do checks on partitions. */
  57                 *p='\0';
  58         }
  59         snprintf(buf, 256, "/sys/block/%s/pid", devname);
  60         if((fd=open(buf, O_RDONLY))<0) {
  61                 if(errno==ENOENT) {
  62                         return 1;
  63                 } else {
  64                         return 2;
  65                 }
  66         }
  67         len=read(fd, buf, 256);
  68         buf[len-1]='\0';
  69         if(do_print) printf("%s\n", buf);
  70         return 0;
  71 }
  72
  73 int opennet(char *name, int port, int sdp) {
  74         int sock;
  75         char portstr[6];
  76         struct addrinfo hints;
  77         struct addrinfo *ai = NULL;
  78         struct addrinfo *rp = NULL;
  79         int e;
  80
  81         snprintf(portstr, sizeof(portstr), "%d", port);
  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) {
 128         u64 magic, size64;
 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 (magic != cliserv_magic)
 143                 err("Not enough cliserv_magic");
 144         printf(".");
 145
 146         if (read(sock, &size64, sizeof(size64)) < 0)
 147                 err("Failed/3: %m\n");
 148         size64 = ntohll(size64);
 149
 150 #ifdef NBD_SET_SIZE_BLOCKS
 151         if ((size64>>10) > (~0UL >> 1)) {
 152                 printf("size = %luMB", (unsigned long)(size64>>20));
 153                 err("Exported device is too big for me. Get 64-bit machine :-(\n");
 154         } else
 155                 printf("size = %luKB", (unsigned long)(size64>>10));
 156 #else
 157         if (size64 > (~0UL >> 1)) {
 158                 printf("size = %luKB", (unsigned long)(size64>>10));
 159                 err("Exported device is too big. Get 64-bit machine or newer kernel :-(\n");
 160         } else
 161                 printf("size = %lu", (unsigned long)(size64));
 162 #endif
 163
 164         if (read(sock, flags, sizeof(*flags)) < 0)
 165                 err("Failed/4: %m\n");
 166         *flags = ntohl(*flags);
 167
 168         if (read(sock, &buf, 124) < 0)
 169                 err("Failed/5: %m\n");
 170         printf("\n");
 171
 172         *rsize64 = size64;
 173 }
 174
 175 void setsizes(int nbd, u64 size64, int blocksize, u32 flags) {
 176         unsigned long size;
 177         int read_only = (flags & NBD_FLAG_READ_ONLY) ? 1 : 0;
 178
 179 #ifdef NBD_SET_SIZE_BLOCKS
 180         if (size64/blocksize > (~0UL >> 1))
 181                 err("Device too large.\n");
 182         else {
 183                 int er;
 184                 if (ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long)blocksize) < 0)
 185                         err("Ioctl/1.1a failed: %m\n");
 186                 size = (unsigned long)(size64/blocksize);
 187                 if ((er = ioctl(nbd, NBD_SET_SIZE_BLOCKS, size)) < 0)
 188                         err("Ioctl/1.1b failed: %m\n");
 189                 fprintf(stderr, "bs=%d, sz=%lu\n", blocksize, size);
 190         }
 191 #else
 192         if (size64 > (~0UL >> 1)) {
 193                 err("Device too large.\n");
 194         } else {
 195                 size = (unsigned long)size64;
 196                 if (ioctl(nbd, NBD_SET_SIZE, size) < 0)
 197                         err("Ioctl NBD_SET_SIZE failed: %m\n");
 198         }
 199 #endif
 200
 201         ioctl(nbd, NBD_CLEAR_SOCK);
 202
 203         if (ioctl(nbd, BLKROSET, (unsigned long) &read_only) < 0)
 204                 err("Unable to set read-only attribute for device");
 205 }
 206
 207 void set_timeout(int nbd, int timeout) {
 208         if (timeout) {
 209 #ifdef NBD_SET_TIMEOUT
 210                 if (ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long)timeout) < 0)
 211                         err("Ioctl NBD_SET_TIMEOUT failed: %m\n");
 212                 fprintf(stderr, "timeout=%d\n", timeout);
 213 #else
 214                 err("Ioctl NBD_SET_TIMEOUT cannot be called when compiled on a system that does not support it\n");
 215 #endif
 216         }
 217 }
 218
 219 void finish_sock(int sock, int nbd, int swap) {
 220         if (ioctl(nbd, NBD_SET_SOCK, sock) < 0)
 221                 err("Ioctl NBD_SET_SOCK failed: %m\n");
 222
 223         if (swap)
 224                 mlockall(MCL_CURRENT | MCL_FUTURE);
 225 }
 226
 227 void usage(void) {
 228         fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
 229         fprintf(stderr, "Usage: nbd-client [bs=blocksize] [timeout=sec] host port nbd_device [-swap] [-sdp] [-persist] [-nofork]\n");
 230         fprintf(stderr, "Or   : nbd-client -d nbd_device\n");
 231         fprintf(stderr, "Or   : nbd-client -c nbd_device\n");
 232         fprintf(stderr, "Default value for blocksize is 1024 (recommended for ethernet)\n");
 233         fprintf(stderr, "Allowed values for blocksize are 512,1024,2048,4096\n"); /* will be checked in kernel :) */
 234         fprintf(stderr, "Note, that kernel 2.4.2 and older ones do not work correctly with\n");
 235         fprintf(stderr, "blocksizes other than 1024 without patches\n");
 236 }
 237
 238 void disconnect(char* device) {
 239         int nbd = open(device, O_RDWR);
 240         if (nbd < 0)
 241                 err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
 242         printf("Disconnecting: que, ");
 243         if (ioctl(nbd, NBD_CLEAR_QUE)< 0)
 244                 err("Ioctl failed: %m\n");
 245         printf("disconnect, ");
 246 #ifdef NBD_DISCONNECT
 247         if (ioctl(nbd, NBD_DISCONNECT)<0)
 248                 err("Ioctl failed: %m\n");
 249         printf("sock, ");
 250 #else
 251         fprintf(stderr, "Can't disconnect: I was not compiled with disconnect support!\n" );
 252         exit(1);
 253 #endif
 254         if (ioctl(nbd, NBD_CLEAR_SOCK)<0)
 255                 err("Ioctl failed: %m\n");
 256         printf("done\n");
 257 }
 258
 259 int main(int argc, char *argv[]) {
 260         int port=0;
 261         int sock, nbd;
 262         int blocksize=1024;
 263         char *hostname=NULL;
 264         char *nbddev=NULL;
 265         int swap=0;
 266         int cont=0;
 267         int timeout=0;
 268         int sdp=0;
 269         int nofork=0;
 270         u64 size64;
 271         u32 flags;
 272         int i, c;
 273         int nonspecial=0;
 274         struct option long_options[] = {
 275                 { "block-size", required_argument, NULL, 'b' },
 276                 { "check", required_argument, NULL, 'c' },
 277                 { "disconnect", required_argument, NULL, 'd' },
 278                 { "help", no_argument, NULL, 'h' },
 279                 { "nofork", no_argument, NULL, 'n' },
 280                 { "persist", no_argument, NULL, 'p' },
 281                 { "sdp", no_argument, NULL, 'S' },
 282                 { "swap", no_argument, NULL, 's' },
 283                 { "timeout", required_argument, NULL, 't' },
 284         };
 285
 286         logging();
 287
 288         while((c=getopt_long_only(argc, argv, "-b:c:d:hnpSst:", long_options, NULL))>=0) {
 289                 switch(c) {
 290                 case 1:
 291                         // non-option argument
 292                         if(strchr(optarg, '=')) {
 293                                 // old-style 'bs=' or 'timeout='
 294                                 // argument
 295                                 fprintf(stderr, "WARNING: old-style command-line argument encountered. This is deprecated.\n");
 296                                 if(!strncmp(optarg, "bs=", 3)) {
 297                                         optarg+=3;
 298                                         goto blocksize;
 299                                 }
 300                                 if(!strncmp(optarg, "timeout=", 8)) {
 301                                         optarg+=8;
 302                                         goto timeout;
 303                                 }
 304                                 fprintf(stderr, "ERROR: unknown option %s encountered\n", optarg);
 305                                 exit(EXIT_FAILURE);
 306                         }
 307                         switch(nonspecial++) {
 308                                 case 0:
 309                                         // host
 310                                         hostname=optarg;
 311                                         break;
 312                                 case 1:
 313                                         // port
 314                                         port = strtol(optarg, NULL, 0);
 315                                         break;
 316                                 case 2:
 317                                         // device
 318                                         nbddev = optarg;
 319                                         break;
 320                                 default:
 321                                         fprintf(stderr, "ERROR: too many non-option arguments specified\n");
 322                                         exit(EXIT_FAILURE);
 323                         }
 324                         break;
 325                 case 'b':
 326                       blocksize:
 327                         blocksize=(int)strtol(optarg, NULL, 0);
 328                         break;
 329                 case 'c':
 330                         check_conn(optarg, 1);
 331                         exit(EXIT_SUCCESS);
 332                 case 'd':
 333                         disconnect(optarg);
 334                         exit(EXIT_SUCCESS);
 335                 case 'h':
 336                         usage();
 337                         exit(EXIT_SUCCESS);
 338                 case 'n':
 339                         nofork=1;
 340                         break;
 341                 case 'p':
 342                         cont=1;
 343                         break;
 344                 case 's':
 345                         swap=1;
 346                         break;
 347                 case 'S':
 348                         sdp=1;
 349                         break;
 350                 case 't':
 351                       timeout:
 352                         timeout=strtol(optarg, NULL, 0);
 353                         break;
 354                 default:
 355                         fprintf(stderr, "E: option eaten by 42 mice\n");
 356                         exit(EXIT_FAILURE);
 357                 }
 358         }
 359
 360         if(!port || !hostname || !nbddev) {
 361                 usage();
 362                 exit(EXIT_FAILURE);
 363         }
 364
 365         nbd = open(nbddev, O_RDWR);
 366         if (nbd < 0)
 367           err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
 368         ++argv; --argc; /* skip device */
 369
 370         sock = opennet(hostname, port, sdp);
 371
 372         negotiate(sock, &size64, &flags);
 373         setsizes(nbd, size64, blocksize, flags);
 374         set_timeout(nbd, timeout);
 375         finish_sock(sock, nbd, swap);
 376
 377         /* Go daemon */
 378
 379 #ifndef NOFORK
 380         if(!nofork) daemon(0,0);
 381 #endif
 382         do {
 383 #ifndef NOFORK
 384                 if (fork()) {
 385                         /* Due to a race, the kernel NBD driver cannot
 386                          * call for a reread of the partition table
 387                          * in the handling of the NBD_DO_IT ioctl().
 388                          * Therefore, this is done in the first open()
 389                          * of the device. We therefore make sure that
 390                          * the device is opened at least once after the
 391                          * connection was made. This has to be done in a
 392                          * separate process, since the NBD_DO_IT ioctl()
 393                          * does not return until the NBD device has
 394                          * disconnected.
 395                          */
 396                         while(check_conn(nbddev, 0)) {
 397                                 sleep(1);
 398                         }
 399                         open(nbddev, O_RDONLY);
 400                         exit(0);
 401                 }
 402 #endif
 403
 404                 if (ioctl(nbd, NBD_DO_IT) < 0) {
 405                         fprintf(stderr, "Kernel call returned: %m");
 406                         if(errno==EBADR) {
 407                                 /* The user probably did 'nbd-client -d' on us.
 408                                  * quit */
 409                                 cont=0;
 410                         } else {
 411                                 if(cont) {
 412                                         u64 new_size;
 413                                         u32 new_flags;
 414
 415                                         fprintf(stderr, " Reconnecting\n");
 416                                         close(sock); close(nbd);
 417                                         sock = opennet(hostname, port, sdp);
 418                                         nbd = open(nbddev, O_RDWR);
 419                                         negotiate(sock, &new_size, &new_flags);
 420                                         if (size64 != new_size) {
 421                                                 err("Size of the device changed. Bye");
 422                                         }
 423                                         setsizes(nbd, size64, blocksize,
 424                                                                 new_flags);
 425
 426                                         set_timeout(nbd, timeout);
 427                                         finish_sock(sock,nbd,swap);
 428                                 }
 429                         }
 430                 } else {
 431                         /* We're on 2.4. It's not clearly defined what exactly
 432                          * happened at this point. Probably best to quit, now
 433                          */
 434                         fprintf(stderr, "Kernel call returned.");
 435                         cont=0;
 436                 }
 437         } while(cont);
 438         printf("Closing: que, ");
 439         ioctl(nbd, NBD_CLEAR_QUE);
 440         printf("sock, ");
 441         ioctl(nbd, NBD_CLEAR_SOCK);
 442         printf("done\n");
 443         return 0;
 444 }