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
  53         if(!strncmp(devname, "/dev/", 5)) {
  54                 devname+=5;
  55         }
  56         if((p=strchr(devname, 'p'))) {
  57                 /* We can't do checks on partitions. */
  58                 *p='\0';
  59         }
  60         snprintf(buf, 256, "/sys/block/%s/pid", devname);
  61         if((fd=open(buf, O_RDONLY))<0) {
  62                 if(errno==ENOENT) {
  63                         return 1;
  64                 } else {
  65                         return 2;
  66                 }
  67         }
  68         len=read(fd, buf, 256);
  69         buf[len-1]='\0';
  70         if(do_print) printf("%s\n", buf);
  71         return 0;
  72 }
  73
  74 int opennet(char *name, int port, int sdp) {
  75         int sock;
  76         char portstr[6];
  77         struct addrinfo hints;
  78         struct addrinfo *ai = NULL;
  79         struct addrinfo *rp = NULL;
  80         int e;
  81
  82         snprintf(portstr, sizeof(portstr), "%d", port);
  83
  84         memset(&hints,'\0',sizeof(hints));
  85         hints.ai_family = AF_UNSPEC;
  86         hints.ai_socktype = SOCK_STREAM;
  87         hints.ai_flags = AI_ADDRCONFIG | AI_NUMERICSERV;
  88         hints.ai_protocol = IPPROTO_TCP;
  89
  90         e = getaddrinfo(name, portstr, &hints, &ai);
  91
  92         if(e != 0) {
  93                 fprintf(stderr, "getaddrinfo failed: %s\n", gai_strerror(e));
  94                 freeaddrinfo(ai);
  95                 exit(EXIT_FAILURE);
  96         }
  97
  98         if(sdp) {
  99 #ifdef WITH_SDP
 100                 if (ai->ai_family == AF_INET)
 101                         ai->ai_family = AF_INET_SDP;
 102                 else (ai->ai_family == AF_INET6)
 103                         ai->ai_family = AF_INET6_SDP;
 104 #else
 105                 err("Can't do SDP: I was not compiled with SDP support!");
 106 #endif
 107         }
 108
 109         for(rp = ai; rp != NULL; rp = rp->ai_next) {
 110                 sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 111
 112                 if(sock == -1)
 113                         continue;       /* error */
 114
 115                 if(connect(sock, rp->ai_addr, rp->ai_addrlen) != -1)
 116                         break;          /* success */
 117         }
 118
 119         if (rp == NULL)
 120                 err("Socket failed: %m");
 121
 122         setmysockopt(sock);
 123
 124         freeaddrinfo(ai);
 125         return sock;
 126 }
 127
 128 void negotiate(int sock, u64 *rsize64, u32 *flags) {
 129         u64 magic, size64;
 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 (magic != cliserv_magic)
 144                 err("Not enough cliserv_magic");
 145         printf(".");
 146
 147         if (read(sock, &size64, sizeof(size64)) < 0)
 148                 err("Failed/3: %m\n");
 149         size64 = ntohll(size64);
 150
 151 #ifdef NBD_SET_SIZE_BLOCKS
 152         if ((size64>>10) > (~0UL >> 1)) {
 153                 printf("size = %luMB", (unsigned long)(size64>>20));
 154                 err("Exported device is too big for me. Get 64-bit machine :-(\n");
 155         } else
 156                 printf("size = %luKB", (unsigned long)(size64>>10));
 157 #else
 158         if (size64 > (~0UL >> 1)) {
 159                 printf("size = %luKB", (unsigned long)(size64>>10));
 160                 err("Exported device is too big. Get 64-bit machine or newer kernel :-(\n");
 161         } else
 162                 printf("size = %lu", (unsigned long)(size64));
 163 #endif
 164
 165         if (read(sock, flags, sizeof(*flags)) < 0)
 166                 err("Failed/4: %m\n");
 167         *flags = ntohl(*flags);
 168
 169         if (read(sock, &buf, 124) < 0)
 170                 err("Failed/5: %m\n");
 171         printf("\n");
 172
 173         *rsize64 = size64;
 174 }
 175
 176 void setsizes(int nbd, u64 size64, int blocksize, u32 flags) {
 177         unsigned long size;
 178         int read_only = (flags & NBD_FLAG_READ_ONLY) ? 1 : 0;
 179
 180 #ifdef NBD_SET_SIZE_BLOCKS
 181         if (size64/blocksize > (~0UL >> 1))
 182                 err("Device too large.\n");
 183         else {
 184                 int er;
 185                 if (ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long)blocksize) < 0)
 186                         err("Ioctl/1.1a failed: %m\n");
 187                 size = (unsigned long)(size64/blocksize);
 188                 if ((er = ioctl(nbd, NBD_SET_SIZE_BLOCKS, size)) < 0)
 189                         err("Ioctl/1.1b failed: %m\n");
 190                 fprintf(stderr, "bs=%d, sz=%lu\n", blocksize, size);
 191         }
 192 #else
 193         if (size64 > (~0UL >> 1)) {
 194                 err("Device too large.\n");
 195         } else {
 196                 size = (unsigned long)size64;
 197                 if (ioctl(nbd, NBD_SET_SIZE, size) < 0)
 198                         err("Ioctl NBD_SET_SIZE failed: %m\n");
 199         }
 200 #endif
 201
 202         ioctl(nbd, NBD_CLEAR_SOCK);
 203
 204         if (ioctl(nbd, BLKROSET, (unsigned long) &read_only) < 0)
 205                 err("Unable to set read-only attribute for device");
 206 }
 207
 208 void set_timeout(int nbd, int timeout) {
 209         if (timeout) {
 210 #ifdef NBD_SET_TIMEOUT
 211                 if (ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long)timeout) < 0)
 212                         err("Ioctl NBD_SET_TIMEOUT failed: %m\n");
 213                 fprintf(stderr, "timeout=%d\n", timeout);
 214 #else
 215                 err("Ioctl NBD_SET_TIMEOUT cannot be called when compiled on a system that does not support it\n");
 216 #endif
 217         }
 218 }
 219
 220 void finish_sock(int sock, int nbd, int swap) {
 221         if (ioctl(nbd, NBD_SET_SOCK, sock) < 0)
 222                 err("Ioctl NBD_SET_SOCK failed: %m\n");
 223
 224         if (swap)
 225                 mlockall(MCL_CURRENT | MCL_FUTURE);
 226 }
 227
 228 void usage(void) {
 229         fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
 230         fprintf(stderr, "Usage: nbd-client [bs=blocksize] [timeout=sec] host port nbd_device [-swap] [-sdp] [-persist] [-nofork]\n");
 231         fprintf(stderr, "Or   : nbd-client -d nbd_device\n");
 232         fprintf(stderr, "Or   : nbd-client -c nbd_device\n");
 233         fprintf(stderr, "Default value for blocksize is 1024 (recommended for ethernet)\n");
 234         fprintf(stderr, "Allowed values for blocksize are 512,1024,2048,4096\n"); /* will be checked in kernel :) */
 235         fprintf(stderr, "Note, that kernel 2.4.2 and older ones do not work correctly with\n");
 236         fprintf(stderr, "blocksizes other than 1024 without patches\n");
 237 }
 238
 239 void disconnect(char* device) {
 240         int nbd = open(device, O_RDWR);
 241
 242         if (nbd < 0)
 243                 err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
 244         printf("Disconnecting: que, ");
 245         if (ioctl(nbd, NBD_CLEAR_QUE)< 0)
 246                 err("Ioctl failed: %m\n");
 247         printf("disconnect, ");
 248 #ifdef NBD_DISCONNECT
 249         if (ioctl(nbd, NBD_DISCONNECT)<0)
 250                 err("Ioctl failed: %m\n");
 251         printf("sock, ");
 252 #else
 253         fprintf(stderr, "Can't disconnect: I was not compiled with disconnect support!\n" );
 254         exit(1);
 255 #endif
 256         if (ioctl(nbd, NBD_CLEAR_SOCK)<0)
 257                 err("Ioctl failed: %m\n");
 258         printf("done\n");
 259 }
 260
 261 int main(int argc, char *argv[]) {
 262         int port=0;
 263         int sock, nbd;
 264         int blocksize=1024;
 265         char *hostname=NULL;
 266         char *nbddev=NULL;
 267         int swap=0;
 268         int cont=0;
 269         int timeout=0;
 270         int sdp=0;
 271         int nofork=0;
 272         u64 size64;
 273         u32 flags;
 274         int i, c;
 275         int nonspecial=0;
 276         struct option long_options[] = {
 277                 { "block-size", required_argument, NULL, 'b' },
 278                 { "check", required_argument, NULL, 'c' },
 279                 { "disconnect", required_argument, NULL, 'd' },
 280                 { "help", no_argument, NULL, 'h' },
 281                 { "nofork", no_argument, NULL, 'n' },
 282                 { "persist", no_argument, NULL, 'p' },
 283                 { "sdp", no_argument, NULL, 'S' },
 284                 { "swap", no_argument, NULL, 's' },
 285                 { "timeout", required_argument, NULL, 't' },
 286         };
 287
 288         logging();
 289
 290         while((c=getopt_long_only(argc, argv, "-b:c:d:hnpSst:", long_options, NULL))>=0) {
 291                 switch(c) {
 292                 case 1:
 293                         // non-option argument
 294                         if(strchr(optarg, '=')) {
 295                                 // old-style 'bs=' or 'timeout='
 296                                 // argument
 297                                 fprintf(stderr, "WARNING: old-style command-line argument encountered. This is deprecated.\n");
 298                                 if(!strncmp(optarg, "bs=", 3)) {
 299                                         optarg+=3;
 300                                         goto blocksize;
 301                                 }
 302                                 if(!strncmp(optarg, "timeout=", 8)) {
 303                                         optarg+=8;
 304                                         goto timeout;
 305                                 }
 306                                 fprintf(stderr, "ERROR: unknown option %s encountered\n", optarg);
 307                                 exit(EXIT_FAILURE);
 308                         }
 309                         switch(nonspecial++) {
 310                                 case 0:
 311                                         // host
 312                                         hostname=optarg;
 313                                         break;
 314                                 case 1:
 315                                         // port
 316                                         port = strtol(optarg, NULL, 0);
 317                                         break;
 318                                 case 2:
 319                                         // device
 320                                         nbddev = optarg;
 321                                         break;
 322                                 default:
 323                                         fprintf(stderr, "ERROR: too many non-option arguments specified\n");
 324                                         exit(EXIT_FAILURE);
 325                         }
 326                         break;
 327                 case 'b':
 328                       blocksize:
 329                         blocksize=(int)strtol(optarg, NULL, 0);
 330                         break;
 331                 case 'c':
 332                         check_conn(optarg, 1);
 333                         exit(EXIT_SUCCESS);
 334                 case 'd':
 335                         disconnect(optarg);
 336                         exit(EXIT_SUCCESS);
 337                 case 'h':
 338                         usage();
 339                         exit(EXIT_SUCCESS);
 340                 case 'n':
 341                         nofork=1;
 342                         break;
 343                 case 'p':
 344                         cont=1;
 345                         break;
 346                 case 's':
 347                         swap=1;
 348                         break;
 349                 case 'S':
 350                         sdp=1;
 351                         break;
 352                 case 't':
 353                       timeout:
 354                         timeout=strtol(optarg, NULL, 0);
 355                         break;
 356                 default:
 357                         fprintf(stderr, "E: option eaten by 42 mice\n");
 358                         exit(EXIT_FAILURE);
 359                 }
 360         }
 361
 362         if(!port || !hostname || !nbddev) {
 363                 usage();
 364                 exit(EXIT_FAILURE);
 365         }
 366
 367         nbd = open(nbddev, O_RDWR);
 368         if (nbd < 0)
 369           err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
 370         ++argv; --argc; /* skip device */
 371
 372         sock = opennet(hostname, port, sdp);
 373
 374         negotiate(sock, &size64, &flags);
 375         setsizes(nbd, size64, blocksize, flags);
 376         set_timeout(nbd, timeout);
 377         finish_sock(sock, nbd, swap);
 378
 379         /* Go daemon */
 380
 381 #ifndef NOFORK
 382         if(!nofork) daemon(0,0);
 383 #endif
 384         do {
 385 #ifndef NOFORK
 386                 if (fork()) {
 387                         /* Due to a race, the kernel NBD driver cannot
 388                          * call for a reread of the partition table
 389                          * in the handling of the NBD_DO_IT ioctl().
 390                          * Therefore, this is done in the first open()
 391                          * of the device. We therefore make sure that
 392                          * the device is opened at least once after the
 393                          * connection was made. This has to be done in a
 394                          * separate process, since the NBD_DO_IT ioctl()
 395                          * does not return until the NBD device has
 396                          * disconnected.
 397                          */
 398                         while(check_conn(nbddev, 0)) {
 399                                 sleep(1);
 400                         }
 401                         open(nbddev, O_RDONLY);
 402                         exit(0);
 403                 }
 404 #endif
 405
 406                 if (ioctl(nbd, NBD_DO_IT) < 0) {
 407                         fprintf(stderr, "Kernel call returned: %m");
 408                         if(errno==EBADR) {
 409                                 /* The user probably did 'nbd-client -d' on us.
 410                                  * quit */
 411                                 cont=0;
 412                         } else {
 413                                 if(cont) {
 414                                         u64 new_size;
 415                                         u32 new_flags;
 416
 417                                         fprintf(stderr, " Reconnecting\n");
 418                                         close(sock); close(nbd);
 419                                         sock = opennet(hostname, port, sdp);
 420                                         nbd = open(nbddev, O_RDWR);
 421                                         negotiate(sock, &new_size, &new_flags);
 422                                         if (size64 != new_size) {
 423                                                 err("Size of the device changed. Bye");
 424                                         }
 425                                         setsizes(nbd, size64, blocksize,
 426                                                                 new_flags);
 427
 428                                         set_timeout(nbd, timeout);
 429                                         finish_sock(sock,nbd,swap);
 430                                 }
 431                         }
 432                 } else {
 433                         /* We're on 2.4. It's not clearly defined what exactly
 434                          * happened at this point. Probably best to quit, now
 435                          */
 436                         fprintf(stderr, "Kernel call returned.");
 437                         cont=0;
 438                 }
 439         } while(cont);
 440         printf("Closing: que, ");
 441         ioctl(nbd, NBD_CLEAR_QUE);
 442         printf("sock, ");
 443         ioctl(nbd, NBD_CLEAR_SOCK);
 444         printf("done\n");
 445         return 0;
 446 }