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/* nbd-client.c - network block device client
*
* Copyright 2010 Rob Landley <rob@landley.net>
*
* Not in SUSv4.
// This little dance is because a NEWTOY with - in the name tries to do
// things like prototype "nbd-client_main" which isn't a valid symbol. So
// we hide the underscore name and OLDTOY the name we want.
USE_NBD_CLIENT(NEWTOY(nbd_client, "<3>3ns", 0))
USE_NBD_CLIENT(OLDTOY(nbd-client, nbd_client, TOYFLAG_USR|TOYFLAG_BIN))
config NBD_CLIENT
bool "nbd-client"
depends on TOYBOX_FORK
default y
help
usage: nbd-client [-ns] HOST PORT DEVICE
-n Do not fork into background
-s nbd swap support (lock server into memory)
*/
/* TODO:
usage: nbd-client [-sSpn] [-b BLKSZ] [-t SECS] [-N name] HOST PORT DEVICE
-b block size
-t timeout in seconds
-S sdp
-p persist
-n nofork
-d DEVICE
-c DEVICE
*/
#define FOR_nbd_client
#include "toys.h"
#include <linux/nbd.h>
void nbd_client_main(void)
{
int sock = -1, nbd, flags;
unsigned long timeout = 0;
char *host=toys.optargs[0], *port=toys.optargs[1], *device=toys.optargs[2];
uint64_t devsize;
// Repeat until spanked
nbd = xopen(device, O_RDWR);
for (;;) {
int temp;
// Find and connect to server
sock = xconnect(host, port, AF_UNSPEC, SOCK_STREAM, 0, 0);
temp = 1;
setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &temp, sizeof(int));
// Read login data
xreadall(sock, toybuf, 152);
if (memcmp(toybuf, "NBDMAGIC\x00\x00\x42\x02\x81\x86\x12\x53", 16))
error_exit("bad login %s:%s", host, port);
devsize = SWAP_BE64(*(uint64_t *)(toybuf+16));
flags = SWAP_BE32(*(int *)(toybuf+24));
// Set 4k block size. Everything uses that these days.
ioctl(nbd, NBD_SET_BLKSIZE, 4096);
ioctl(nbd, NBD_SET_SIZE_BLOCKS, devsize/4096);
ioctl(nbd, NBD_CLEAR_SOCK);
// If the sucker was exported read only, respect that locally.
temp = (flags & 2) ? 1 : 0;
xioctl(nbd, BLKROSET, &temp);
if (timeout && ioctl(nbd, NBD_SET_TIMEOUT, timeout)<0) break;
if (ioctl(nbd, NBD_SET_SOCK, sock) < 0) break;
if (toys.optflags & FLAG_s) mlockall(MCL_CURRENT|MCL_FUTURE);
// Open the device to force reread of the partition table.
if ((toys.optflags & FLAG_n) || !xfork()) {
char *s = strrchr(device, '/');
int i;
sprintf(toybuf, "/sys/block/%.32s/pid", s ? s+1 : device);
// Is it up yet? (Give it 10 seconds.)
for (i=0; i<100; i++) {
temp = open(toybuf, O_RDONLY);
if (temp == -1) msleep(100);
else {
close(temp);
break;
}
}
close(open(device, O_RDONLY));
if (!(toys.optflags & FLAG_n)) exit(0);
}
// Daemonize here.
if (daemon(0,0)) perror_exit("daemonize");
// Process NBD requests until further notice.
if (ioctl(nbd, NBD_DO_IT)>=0 || errno==EBADR) break;
close(sock);
}
// Flush queue and exit.
ioctl(nbd, NBD_CLEAR_QUE);
ioctl(nbd, NBD_CLEAR_SOCK);
if (CFG_TOYBOX_FREE) close(nbd);
}
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