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 <asm/page.h>
  20 #include <sys/ioctl.h>
  21 #include <sys/socket.h>
  22 #include <sys/types.h>
  23 #include <unistd.h>
  24 #include <netinet/tcp.h>
  25 #include <netinet/in.h>         /* sockaddr_in, htons, in_addr */
  26 #include <netdb.h>              /* hostent, gethostby*, getservby* */
  27 #include <stdio.h>
  28 #include <fcntl.h>
  29 #include <syslog.h>
  30 #include <stdlib.h>
  31
  32 #ifndef __GNUC__
  33 #error I need GCC to work
  34 #endif
  35
  36 #include <linux/ioctl.h>
  37 #define MY_NAME "nbd_client"
  38 #include "cliserv.h"
  39
  40 int opennet(char *name, int port) {
  41         int sock;
  42         struct sockaddr_in xaddrin;
  43         int xaddrinlen = sizeof(xaddrin);
  44         struct hostent *hostn;
  45
  46         hostn = gethostbyname(name);
  47         if (!hostn)
  48                 err("Gethostname failed: %h\n");
  49
  50         if ((sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
  51                 err("Socket failed: %m");
  52
  53         xaddrin.sin_family = AF_INET;
  54         xaddrin.sin_port = htons(port);
  55         xaddrin.sin_addr.s_addr = *((int *) hostn->h_addr);
  56         if ((connect(sock, (struct sockaddr *) &xaddrin, xaddrinlen) < 0))
  57                 err("Connect: %m");
  58
  59         setmysockopt(sock);
  60         return sock;
  61 }
  62
  63 u64 negotiate(int sock, int blocksize) {
  64         u64 magic, size64;
  65         char buf[256] = "\0\0\0\0\0\0\0\0\0";
  66
  67         printf("Negotiation: ");
  68         if (read(sock, buf, 8) < 0)
  69                 err("Failed/1: %m");
  70         if (strlen(buf)==0)
  71                 err("Server closed connection");
  72         if (strcmp(buf, INIT_PASSWD))
  73                 err("INIT_PASSWD bad");
  74         printf(".");
  75         if (read(sock, &magic, sizeof(magic)) < 0)
  76                 err("Failed/2: %m");
  77         magic = ntohll(magic);
  78         if (magic != cliserv_magic)
  79                 err("Not enough cliserv_magic");
  80         printf(".");
  81
  82         if (read(sock, &size64, sizeof(size64)) < 0)
  83                 err("Failed/3: %m\n");
  84         size64 = ntohll(size64);
  85
  86 #ifdef NBD_SET_SIZE_BLOCKS
  87         if ((size64>>10) > (~0UL >> 1)) {
  88                 printf("size = %luMB", (unsigned long)(size64>>20));
  89                 err("Exported device is too big for me. Get 64-bit machine :-(\n");
  90         } else
  91                 printf("size = %luKB", (unsigned long)(size64>>10));
  92 #else
  93         if (size64 > (~0UL >> 1)) {
  94                 printf("size = %luKB", (unsigned long)(size64>>10));
  95                 err("Exported device is too big. Get 64-bit machine or newer kernel :-(\n");
  96         } else
  97                 printf("size = %lu", (unsigned long)(size64));
  98 #endif
  99
 100         if (read(sock, &buf, 128) < 0)
 101                 err("Failed/4: %m\n");
 102         printf("\n");
 103
 104         return size64;
 105 }
 106
 107 void setsizes(int nbd, u64 size64, int blocksize) {
 108         unsigned long size;
 109
 110 #ifdef NBD_SET_SIZE_BLOCKS
 111         if (size64/blocksize > (~0UL >> 1))
 112                 err("Device too large.\n");
 113         else {
 114                 int er;
 115                 if (ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long)blocksize) < 0)
 116                         err("Ioctl/1.1a failed: %m\n");
 117                 size = (unsigned long)(size64/blocksize);
 118                 if ((er = ioctl(nbd, NBD_SET_SIZE_BLOCKS, size)) < 0)
 119                         err("Ioctl/1.1b failed: %m\n");
 120                 fprintf(stderr, "bs=%d, sz=%lu\n", blocksize, size);
 121         }
 122 #else
 123         if (size64 > (~0UL >> 1)) {
 124                 err("Device too large.\n");
 125         } else {
 126                 size = (unsigned long)size64;
 127                 if (ioctl(nbd, NBD_SET_SIZE, size) < 0)
 128                         err("Ioctl NBD_SET_SIZE failed: %m\n");
 129         }
 130 #endif
 131
 132         ioctl(nbd, NBD_CLEAR_SOCK);
 133 }
 134
 135 void finish_sock(int sock, int nbd, int swap) {
 136         if (ioctl(nbd, NBD_SET_SOCK, sock) < 0)
 137                 err("Ioctl NBD_SET_SOCK failed: %m\n");
 138
 139 #ifndef SO_SWAPPING
 140         if (swap)
 141                 err("You have to compile me on machine with swapping patch enabled in order to use it later.");
 142 #else
 143         if (swap)
 144                 if (setsockopt(sock, SOL_SOCKET, SO_SWAPPING, &one, sizeof(int)) < 0)
 145                         err("Could not enable swapping: %m");
 146 #endif
 147 }
 148
 149 int main(int argc, char *argv[]) {
 150         int port, sock, nbd;
 151         int blocksize=1024;
 152         char *hostname, *nbddev;
 153         int swap=0;
 154         int cont=0;
 155         u64 size64;
 156
 157         logging();
 158
 159         if (argc < 3) {
 160         errmsg:
 161                 fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
 162                 fprintf(stderr, "Usage: nbd-client [bs=blocksize] host port nbd_device [-swap] [-persist]\n");
 163                 fprintf(stderr, "Or   : nbd-client -d nbd_device\n");
 164                 fprintf(stderr, "Default value for blocksize is 1024 (recommended for ethernet)\n");
 165                 fprintf(stderr, "Allowed values for blocksize are 512,1024,2048,4096\n"); /* will be checked in kernel :) */
 166                 fprintf(stderr, "Note, that kernel 2.4.2 and older ones do not work correctly with\n");
 167                 fprintf(stderr, "blocksizes other than 1024 without patches\n");
 168                 return 1;
 169         }
 170
 171         ++argv; --argc; /* skip programname */
 172
 173         if (strcmp(argv[0], "-d")==0) {
 174                 nbd = open(argv[1], O_RDWR);
 175                 if (nbd < 0)
 176                         err("Can not open NBD: %m");
 177                 printf("Disconnecting: que, ");
 178                 if (ioctl(nbd, NBD_CLEAR_QUE)< 0)
 179                         err("Ioctl failed: %m\n");
 180                 printf("disconnect, ");
 181 #ifdef NBD_DISCONNECT
 182                 if (ioctl(nbd, NBD_DISCONNECT)<0)
 183                         err("Ioctl failed: %m\n");
 184                 printf("sock, ");
 185 #else
 186                 fprintf(stderr, "Can't disconnect: I was not compiled with disconnect support!\n" );
 187                 exit(1);
 188 #endif
 189                 if (ioctl(nbd, NBD_CLEAR_SOCK)<0)
 190                         err("Ioctl failed: %m\n");
 191                 printf("done\n");
 192                 return 0;
 193         }
 194
 195         if (strncmp(argv[0], "bs=", 3)==0) {
 196                 blocksize=atoi(argv[0]+3);
 197                 ++argv; --argc; /* skip blocksize */
 198         }
 199
 200         if (argc==0) goto errmsg;
 201         hostname=argv[0];
 202         ++argv; --argc; /* skip hostname */
 203
 204         if (argc==0) goto errmsg;
 205         port = atoi(argv[0]);
 206         ++argv; --argc; /* skip port */
 207
 208         if (argc==0) goto errmsg;
 209         sock = opennet(hostname, port);
 210         nbddev = argv[0];
 211         nbd = open(nbddev, O_RDWR);
 212         if (nbd < 0)
 213           err("Can not open NBD: %m");
 214         ++argv; --argc; /* skip device */
 215
 216         if (argc>2) goto errmsg;
 217         if (argc!=0) {
 218                 if(strncmp(argv[0], "-swap", 5)==0) {
 219                         swap=1;
 220                         ++argv;--argc;
 221                 }
 222         }
 223         if (argc!=0) {
 224                 if(strncmp(argv[0], "-persist", 8)==0) {
 225                         cont=1;
 226                         ++argv;--argc;
 227                 }
 228         }
 229         argv=NULL; argc=0; /* don't use it later suddenly */
 230
 231         size64 = negotiate(sock, blocksize);
 232         setsizes(nbd, size64, blocksize);
 233         finish_sock(sock, nbd, swap);
 234
 235         /* Go daemon */
 236
 237         chdir("/");
 238 #ifndef NOFORK
 239         if (fork())
 240                 exit(0);
 241 #endif
 242
 243         do {
 244                 if (ioctl(nbd, NBD_DO_IT) < 0) {
 245                         fprintf(stderr, "Kernel call returned: %m");
 246                         if(errno==EBADR) {
 247                                 /* The user probably did 'nbd-client -d' on us.
 248                                  * quit */
 249                                 cont=0;
 250                         } else {
 251                                 if(cont) {
 252                                         fprintf(stderr, " Reconnecting\n");
 253                                         close(sock); close(nbd);
 254                                         sock = opennet(hostname, port);
 255                                         nbd = open(nbddev, O_RDWR);
 256                                         if(size64!=negotiate(sock,blocksize)) {
 257                                                 err("Size of the device changed. Bye");
 258                                         }
 259                                         setsizes(nbd, size64, blocksize);
 260                                         finish_sock(sock,nbd,swap);
 261                                 }
 262                         }
 263                 } else {
 264                         /* We're on 2.4. It's not clearly defined what exactly
 265                          * happened at this point. Probably best to quit, now
 266                          */
 267                         fprintf(stderr, "Kernel call returned.");
 268                         cont=0;
 269                 }
 270         } while(cont);
 271         printf("Closing: que, ");
 272         ioctl(nbd, NBD_CLEAR_QUE);
 273         printf("sock, ");
 274         ioctl(nbd, NBD_CLEAR_SOCK);
 275         printf("done\n");
 276         return 0;
 277 }