2 * Open connection for network block device
4 * Copyright 1997,1998 Pavel Machek, distribute under GPL
5 * <pavel@atrey.karlin.mff.cuni.cz>
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.
19 #include <sys/ioctl.h>
20 #include <sys/socket.h>
21 #include <sys/types.h>
23 #include <netinet/tcp.h>
24 #include <netinet/in.h> /* sockaddr_in, htons, in_addr */
25 #include <netdb.h> /* hostent, gethostby*, getservby* */
30 #include <sys/mount.h>
35 #error I need GCC to work
38 #include <linux/ioctl.h>
39 #define MY_NAME "nbd_client"
42 int check_conn(char* devname, int do_print) {
47 if(!strncmp(devname, "/dev/", 5)) {
50 if((p=strchr(devname, 'p'))) {
51 /* We can't do checks on partitions. */
54 snprintf(buf, 256, "/sys/block/%s/pid", devname);
55 if((fd=open(buf, O_RDONLY))<0) {
62 len=read(fd, buf, 256);
64 if(do_print) printf("%s\n", buf);
68 int opennet(char *name, int port, int sdp) {
70 struct sockaddr_in xaddrin;
71 int xaddrinlen = sizeof(xaddrin);
72 struct hostent *hostn;
75 hostn = gethostbyname(name);
77 err("Gethostname failed: %h\n");
84 err("Can't do SDP: I was not compiled with SDP support!");
87 if ((sock = socket(af, SOCK_STREAM, IPPROTO_TCP)) < 0)
88 err("Socket failed: %m");
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))
100 void negotiate(int sock, u64 *rsize64, u32 *flags) {
102 char buf[256] = "\0\0\0\0\0\0\0\0\0";
104 printf("Negotiation: ");
105 if (read(sock, buf, 8) < 0)
108 err("Server closed connection");
109 if (strcmp(buf, INIT_PASSWD))
110 err("INIT_PASSWD bad");
112 if (read(sock, &magic, sizeof(magic)) < 0)
114 magic = ntohll(magic);
115 if (magic != cliserv_magic)
116 err("Not enough cliserv_magic");
119 if (read(sock, &size64, sizeof(size64)) < 0)
120 err("Failed/3: %m\n");
121 size64 = ntohll(size64);
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");
128 printf("size = %luKB", (unsigned long)(size64>>10));
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");
134 printf("size = %lu", (unsigned long)(size64));
137 if (read(sock, flags, sizeof(*flags)) < 0)
138 err("Failed/4: %m\n");
139 *flags = ntohl(*flags);
141 if (read(sock, &buf, 124) < 0)
142 err("Failed/5: %m\n");
148 void setsizes(int nbd, u64 size64, int blocksize, u32 flags) {
150 int read_only = (flags & NBD_FLAG_READ_ONLY) ? 1 : 0;
152 #ifdef NBD_SET_SIZE_BLOCKS
153 if (size64/blocksize > (~0UL >> 1))
154 err("Device too large.\n");
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);
165 if (size64 > (~0UL >> 1)) {
166 err("Device too large.\n");
168 size = (unsigned long)size64;
169 if (ioctl(nbd, NBD_SET_SIZE, size) < 0)
170 err("Ioctl NBD_SET_SIZE failed: %m\n");
174 ioctl(nbd, NBD_CLEAR_SOCK);
176 if (ioctl(nbd, BLKROSET, (unsigned long) &read_only) < 0)
177 err("Unable to set read-only attribute for device");
180 void set_timeout(int nbd, int timeout) {
182 #ifdef NBD_SET_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);
187 err("Ioctl NBD_SET_TIMEOUT cannot be called when compiled on a system that does not support it\n");
192 void finish_sock(int sock, int nbd, int swap) {
193 if (ioctl(nbd, NBD_SET_SOCK, sock) < 0)
194 err("Ioctl NBD_SET_SOCK failed: %m\n");
197 mlockall(MCL_CURRENT | MCL_FUTURE);
200 int main(int argc, char *argv[]) {
203 char *hostname, *nbddev;
216 fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
217 fprintf(stderr, "Usage: nbd-client [bs=blocksize] [timeout=sec] host port nbd_device [-swap] [-persist] [-nofork]\n");
218 fprintf(stderr, "Or : nbd-client -d nbd_device\n");
219 fprintf(stderr, "Or : nbd-client -c nbd_device\n");
220 fprintf(stderr, "Default value for blocksize is 1024 (recommended for ethernet)\n");
221 fprintf(stderr, "Allowed values for blocksize are 512,1024,2048,4096\n"); /* will be checked in kernel :) */
222 fprintf(stderr, "Note, that kernel 2.4.2 and older ones do not work correctly with\n");
223 fprintf(stderr, "blocksizes other than 1024 without patches\n");
227 ++argv; --argc; /* skip programname */
229 if (strcmp(argv[0], "-d")==0) {
230 nbd = open(argv[1], O_RDWR);
232 err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
233 printf("Disconnecting: que, ");
234 if (ioctl(nbd, NBD_CLEAR_QUE)< 0)
235 err("Ioctl failed: %m\n");
236 printf("disconnect, ");
237 #ifdef NBD_DISCONNECT
238 if (ioctl(nbd, NBD_DISCONNECT)<0)
239 err("Ioctl failed: %m\n");
242 fprintf(stderr, "Can't disconnect: I was not compiled with disconnect support!\n" );
245 if (ioctl(nbd, NBD_CLEAR_SOCK)<0)
246 err("Ioctl failed: %m\n");
250 if(strcmp(argv[0], "-c")==0) {
251 return check_conn(argv[1], 1);
254 if (strncmp(argv[0], "bs=", 3)==0) {
255 blocksize=atoi(argv[0]+3);
256 ++argv; --argc; /* skip blocksize */
259 if (strncmp(argv[0], "timeout=", 8)==0) {
260 timeout=atoi(argv[0]+8);
261 ++argv; --argc; /* skip timeout */
264 if (argc==0) goto errmsg;
266 ++argv; --argc; /* skip hostname */
268 if (argc==0) goto errmsg;
269 port = atoi(argv[0]);
270 ++argv; --argc; /* skip port */
272 if (argc==0) goto errmsg;
274 nbd = open(nbddev, O_RDWR);
276 err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
277 ++argv; --argc; /* skip device */
279 if (argc>3) goto errmsg;
281 if(strncmp(argv[0], "-swap", 5)==0) {
287 if(strncmp(argv[0], "-persist", 8)==0) {
293 if(strncmp(argv[0], "-sdp", 4)==0) {
299 if(strncmp(argv[0], "-nofork", 7)==0) {
304 if(argc) goto errmsg;
305 sock = opennet(hostname, port, sdp);
306 argv=NULL; argc=0; /* don't use it later suddenly */
308 negotiate(sock, &size64, &flags);
309 setsizes(nbd, size64, blocksize, flags);
310 set_timeout(nbd, timeout);
311 finish_sock(sock, nbd, swap);
316 if(!nofork) daemon(0,0);
319 /* Due to a race, the kernel NBD driver cannot
320 * call for a reread of the partition table
321 * in the handling of the NBD_DO_IT ioctl().
322 * Therefore, this is done in the first open()
323 * of the device. We therefore make sure that
324 * the device is opened at least once after the
325 * connection was made. This has to be done in a
326 * separate process, since the NBD_DO_IT ioctl()
327 * does not return until the NBD device has
330 while(check_conn(nbddev, 0)) {
333 open(nbddev, O_RDONLY);
338 if (ioctl(nbd, NBD_DO_IT) < 0) {
339 fprintf(stderr, "Kernel call returned: %m");
341 /* The user probably did 'nbd-client -d' on us.
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");
357 setsizes(nbd, size64, blocksize,
360 set_timeout(nbd, timeout);
361 finish_sock(sock,nbd,swap);
365 /* We're on 2.4. It's not clearly defined what exactly
366 * happened at this point. Probably best to quit, now
368 fprintf(stderr, "Kernel call returned.");
372 printf("Closing: que, ");
373 ioctl(nbd, NBD_CLEAR_QUE);
375 ioctl(nbd, NBD_CLEAR_SOCK);