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  */
  15
  16 #include "config.h"
  17 #include "lfs.h"
  18
  19 #include <sys/ioctl.h>
  20 #include <sys/socket.h>
  21 #include <sys/types.h>
  22 #include <unistd.h>
  23 #include <netinet/tcp.h>
  24 #include <netinet/in.h>         /* sockaddr_in, htons, in_addr */
  25 #include <netdb.h>              /* hostent, gethostby*, getservby* */
  26 #include <stdio.h>
  27 #include <fcntl.h>
  28 #include <syslog.h>
  29 #include <stdlib.h>
  30 #include <sys/mount.h>
  31 #include <sys/mman.h>
  32 #include <errno.h>
  33
  34 #ifndef __GNUC__
  35 #error I need GCC to work
  36 #endif
  37
  38 #include <linux/ioctl.h>
  39 #define MY_NAME "nbd_client"
  40 #include "cliserv.h"
  41
  42 int check_conn(char* devname, int do_print) {
  43         char buf[256];
  44         char* p;
  45         int fd;
  46         int len;
  47         if(!strncmp(devname, "/dev/", 5)) {
  48                 devname+=5;
  49         }
  50         if((p=strchr(devname, 'p'))) {
  51                 /* We can't do checks on partitions. */
  52                 *p='\0';
  53         }
  54         snprintf(buf, 256, "/sys/block/%s/pid", devname);
  55         if((fd=open(buf, O_RDONLY))<0) {
  56                 if(errno==ENOENT) {
  57                         return 1;
  58                 } else {
  59                         return 2;
  60                 }
  61         }
  62         len=read(fd, buf, 256);
  63         buf[len-1]='\0';
  64         if(do_print) printf("%s\n", buf);
  65         return 0;
  66 }
  67
  68 int opennet(char *name, int port, int sdp) {
  69         int sock;
  70         struct sockaddr_in xaddrin;
  71         int xaddrinlen = sizeof(xaddrin);
  72         struct hostent *hostn;
  73         int af;
  74
  75         hostn = gethostbyname(name);
  76         if (!hostn)
  77                 err("Gethostname failed: %h\n");
  78
  79         af = AF_INET;
  80         if(sdp) {
  81 #ifdef WITH_SDP
  82                 af = AF_INET_SDP;
  83 #else
  84                 err("Can't do SDP: I was not compiled with SDP support!");
  85 #endif
  86         }
  87         if ((sock = socket(af, SOCK_STREAM, IPPROTO_TCP)) < 0)
  88                 err("Socket failed: %m");
  89
  90         xaddrin.sin_family = af;
  91         xaddrin.sin_port = htons(port);
  92         xaddrin.sin_addr.s_addr = *((int *) hostn->h_addr);
  93         if ((connect(sock, (struct sockaddr *) &xaddrin, xaddrinlen) < 0))
  94                 err("Connect: %m");
  95
  96         setmysockopt(sock);
  97         return sock;
  98 }
  99
 100 void negotiate(int sock, u64 *rsize64, u32 *flags) {
 101         u64 magic, size64;
 102         char buf[256] = "\0\0\0\0\0\0\0\0\0";
 103
 104         printf("Negotiation: ");
 105         if (read(sock, buf, 8) < 0)
 106                 err("Failed/1: %m");
 107         if (strlen(buf)==0)
 108                 err("Server closed connection");
 109         if (strcmp(buf, INIT_PASSWD))
 110                 err("INIT_PASSWD bad");
 111         printf(".");
 112         if (read(sock, &magic, sizeof(magic)) < 0)
 113                 err("Failed/2: %m");
 114         magic = ntohll(magic);
 115         if (magic != cliserv_magic)
 116                 err("Not enough cliserv_magic");
 117         printf(".");
 118
 119         if (read(sock, &size64, sizeof(size64)) < 0)
 120                 err("Failed/3: %m\n");
 121         size64 = ntohll(size64);
 122
 123 #ifdef NBD_SET_SIZE_BLOCKS
 124         if ((size64>>10) > (~0UL >> 1)) {
 125                 printf("size = %luMB", (unsigned long)(size64>>20));
 126                 err("Exported device is too big for me. Get 64-bit machine :-(\n");
 127         } else
 128                 printf("size = %luKB", (unsigned long)(size64>>10));
 129 #else
 130         if (size64 > (~0UL >> 1)) {
 131                 printf("size = %luKB", (unsigned long)(size64>>10));
 132                 err("Exported device is too big. Get 64-bit machine or newer kernel :-(\n");
 133         } else
 134                 printf("size = %lu", (unsigned long)(size64));
 135 #endif
 136
 137         if (read(sock, flags, sizeof(*flags)) < 0)
 138                 err("Failed/4: %m\n");
 139         *flags = ntohl(*flags);
 140
 141         if (read(sock, &buf, 124) < 0)
 142                 err("Failed/5: %m\n");
 143         printf("\n");
 144
 145         *rsize64 = size64;
 146 }
 147
 148 void setsizes(int nbd, u64 size64, int blocksize, u32 flags) {
 149         unsigned long size;
 150         int read_only = (flags & NBD_FLAG_READ_ONLY) ? 1 : 0;
 151
 152 #ifdef NBD_SET_SIZE_BLOCKS
 153         if (size64/blocksize > (~0UL >> 1))
 154                 err("Device too large.\n");
 155         else {
 156                 int er;
 157                 if (ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long)blocksize) < 0)
 158                         err("Ioctl/1.1a failed: %m\n");
 159                 size = (unsigned long)(size64/blocksize);
 160                 if ((er = ioctl(nbd, NBD_SET_SIZE_BLOCKS, size)) < 0)
 161                         err("Ioctl/1.1b failed: %m\n");
 162                 fprintf(stderr, "bs=%d, sz=%lu\n", blocksize, size);
 163         }
 164 #else
 165         if (size64 > (~0UL >> 1)) {
 166                 err("Device too large.\n");
 167         } else {
 168                 size = (unsigned long)size64;
 169                 if (ioctl(nbd, NBD_SET_SIZE, size) < 0)
 170                         err("Ioctl NBD_SET_SIZE failed: %m\n");
 171         }
 172 #endif
 173
 174         ioctl(nbd, NBD_CLEAR_SOCK);
 175
 176         if (ioctl(nbd, BLKROSET, (unsigned long) &read_only) < 0)
 177                 err("Unable to set read-only attribute for device");
 178 }
 179
 180 void set_timeout(int nbd, int timeout) {
 181 #ifdef NBD_SET_TIMEOUT
 182         if (timeout) {
 183                 if (ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long)timeout) < 0)
 184                         err("Ioctl NBD_SET_TIMEOUT failed: %m\n");
 185                 fprintf(stderr, "timeout=%d\n", timeout);
 186         }
 187 #endif
 188 }
 189
 190 void finish_sock(int sock, int nbd, int swap) {
 191         if (ioctl(nbd, NBD_SET_SOCK, sock) < 0)
 192                 err("Ioctl NBD_SET_SOCK failed: %m\n");
 193
 194 /*
 195  * If anyone ever forward-patches this patch, I'll happily re-enable
 196  * this code. Until then...
 197 #ifndef SO_SWAPPING
 198         if (swap)
 199                 err("You have to compile me on machine with swapping patch enabled in order to use it later.");
 200 #else
 201         if (swap)
 202                 if (setsockopt(sock, SOL_SOCKET, SO_SWAPPING, &one, sizeof(int)) < 0)
 203                         err("Could not enable swapping: %m");
 204 #endif
 205 */
 206         mlockall(MCL_CURRENT | MCL_FUTURE);
 207 }
 208
 209 int main(int argc, char *argv[]) {
 210         int port, sock, nbd;
 211         int blocksize=1024;
 212         char *hostname, *nbddev;
 213         int swap=0;
 214         int cont=0;
 215         int timeout=0;
 216         int sdp=0;
 217         int nofork=0;
 218         u64 size64;
 219         u32 flags;
 220
 221         logging();
 222
 223         if (argc < 3) {
 224         errmsg:
 225                 fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
 226                 fprintf(stderr, "Usage: nbd-client [bs=blocksize] [timeout=sec] host port nbd_device [-swap] [-persist] [-nofork]\n");
 227                 fprintf(stderr, "Or   : nbd-client -d nbd_device\n");
 228                 fprintf(stderr, "Or   : nbd-client -c nbd_device\n");
 229                 fprintf(stderr, "Default value for blocksize is 1024 (recommended for ethernet)\n");
 230                 fprintf(stderr, "Allowed values for blocksize are 512,1024,2048,4096\n"); /* will be checked in kernel :) */
 231                 fprintf(stderr, "Note, that kernel 2.4.2 and older ones do not work correctly with\n");
 232                 fprintf(stderr, "blocksizes other than 1024 without patches\n");
 233                 return 1;
 234         }
 235
 236         ++argv; --argc; /* skip programname */
 237
 238         if (strcmp(argv[0], "-d")==0) {
 239                 nbd = open(argv[1], 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                 return 0;
 258         }
 259         if(strcmp(argv[0], "-c")==0) {
 260                 return check_conn(argv[1], 1);
 261         }
 262
 263         if (strncmp(argv[0], "bs=", 3)==0) {
 264                 blocksize=atoi(argv[0]+3);
 265                 ++argv; --argc; /* skip blocksize */
 266         }
 267
 268         if (strncmp(argv[0], "timeout=", 8)==0) {
 269                 timeout=atoi(argv[0]+8);
 270                 ++argv; --argc; /* skip timeout */
 271         }
 272
 273         if (argc==0) goto errmsg;
 274         hostname=argv[0];
 275         ++argv; --argc; /* skip hostname */
 276
 277         if (argc==0) goto errmsg;
 278         port = atoi(argv[0]);
 279         ++argv; --argc; /* skip port */
 280
 281         if (argc==0) goto errmsg;
 282         nbddev = argv[0];
 283         nbd = open(nbddev, O_RDWR);
 284         if (nbd < 0)
 285           err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
 286         ++argv; --argc; /* skip device */
 287
 288         if (argc>3) goto errmsg;
 289         if (argc) {
 290                 if(strncmp(argv[0], "-swap", 5)==0) {
 291                         swap=1;
 292                         ++argv;--argc;
 293                 }
 294         }
 295         if (argc) {
 296                 if(strncmp(argv[0], "-persist", 8)==0) {
 297                         cont=1;
 298                         ++argv;--argc;
 299                 }
 300         }
 301         if (argc) {
 302                 if(strncmp(argv[0], "-sdp", 4)==0) {
 303                         sdp=1;
 304                         ++argv;--argc;
 305                 }
 306         }
 307         if (argc) {
 308                 if(strncmp(argv[0], "-nofork", 7)==0) {
 309                         nofork=1;
 310                         ++argv;--argc;
 311                 }
 312         }
 313         if(argc) goto errmsg;
 314         sock = opennet(hostname, port, sdp);
 315         argv=NULL; argc=0; /* don't use it later suddenly */
 316
 317         negotiate(sock, &size64, &flags);
 318         setsizes(nbd, size64, blocksize, flags);
 319         set_timeout(nbd, timeout);
 320         finish_sock(sock, nbd, swap);
 321
 322         /* Go daemon */
 323
 324         daemon(0,0);
 325         do {
 326 #ifndef NOFORK
 327                 if (!nofork) {
 328                         if (fork()) {
 329                                 while(check_conn(nbddev, 0)) {
 330                                         sleep(1);
 331                                 }
 332                                 open(nbddev, O_RDONLY);
 333                                 exit(0);
 334                         }
 335                 }
 336 #endif
 337
 338                 if (ioctl(nbd, NBD_DO_IT) < 0) {
 339                         fprintf(stderr, "Kernel call returned: %m");
 340                         if(errno==EBADR) {
 341                                 /* The user probably did 'nbd-client -d' on us.
 342                                  * quit */
 343                                 cont=0;
 344                         } else {
 345                                 if(cont) {
 346                                         u64 new_size;
 347                                         u32 new_flags;
 348
 349                                         fprintf(stderr, " Reconnecting\n");
 350                                         close(sock); close(nbd);
 351                                         sock = opennet(hostname, port, sdp);
 352                                         nbd = open(nbddev, O_RDWR);
 353                                         negotiate(sock, &new_size, &new_flags);
 354                                         if (size64 != new_size) {
 355                                                 err("Size of the device changed. Bye");
 356                                         }
 357                                         setsizes(nbd, size64, blocksize,
 358                                                                 new_flags);
 359
 360                                         set_timeout(nbd, timeout);
 361                                         finish_sock(sock,nbd,swap);
 362                                 }
 363                         }
 364                 } else {
 365                         /* We're on 2.4. It's not clearly defined what exactly
 366                          * happened at this point. Probably best to quit, now
 367                          */
 368                         fprintf(stderr, "Kernel call returned.");
 369                         cont=0;
 370                 }
 371         } while(cont);
 372         printf("Closing: que, ");
 373         ioctl(nbd, NBD_CLEAR_QUE);
 374         printf("sock, ");
 375         ioctl(nbd, NBD_CLEAR_SOCK);
 376         printf("done\n");
 377         return 0;
 378 }