1/* nbd-client.c - network block device client 2 * 3 * Copyright 2010 Rob Landley <rob@landley.net> 4 * 5 * Not in SUSv4. 6 7// This little dance is because a NEWTOY with - in the name tries to do 8// things like prototype "nbd-client_main" which isn't a valid symbol. So 9// we hide the underscore name and OLDTOY the name we want. 10USE_NBD_CLIENT(NEWTOY(nbd_client, "<3>3ns", 0)) 11USE_NBD_CLIENT(OLDTOY(nbd-client, nbd_client, TOYFLAG_USR|TOYFLAG_BIN)) 12 13config NBD_CLIENT 14 bool "nbd-client" 15 depends on TOYBOX_FORK 16 default y 17 help 18 usage: nbd-client [-ns] HOST PORT DEVICE 19 20 -n Do not fork into background 21 -s nbd swap support (lock server into memory) 22*/ 23 24/* TODO: 25 usage: nbd-client [-sSpn] [-b BLKSZ] [-t SECS] [-N name] HOST PORT DEVICE 26 27 -b block size 28 -t timeout in seconds 29 -S sdp 30 -p persist 31 -n nofork 32 -d DEVICE 33 -c DEVICE 34*/ 35 36#define FOR_nbd_client 37#include "toys.h" 38#include <linux/nbd.h> 39 40void nbd_client_main(void) 41{ 42 int sock = -1, nbd, flags; 43 unsigned long timeout = 0; 44 char *host=toys.optargs[0], *port=toys.optargs[1], *device=toys.optargs[2]; 45 uint64_t devsize; 46 47 // Repeat until spanked 48 49 nbd = xopen(device, O_RDWR); 50 for (;;) { 51 int temp; 52 53 // Find and connect to server 54 55 sock = xconnectany(xgetaddrinfo(host, port, AF_UNSPEC, SOCK_STREAM, 0, 0)); 56 temp = 1; 57 setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &temp, sizeof(int)); 58 59 // Read login data 60 61 xreadall(sock, toybuf, 152); 62 if (memcmp(toybuf, "NBDMAGIC\x00\x00\x42\x02\x81\x86\x12\x53", 16)) 63 error_exit("bad login %s:%s", host, port); 64 devsize = SWAP_BE64(*(uint64_t *)(toybuf+16)); 65 flags = SWAP_BE32(*(int *)(toybuf+24)); 66 67 // Set 4k block size. Everything uses that these days. 68 ioctl(nbd, NBD_SET_BLKSIZE, 4096); 69 ioctl(nbd, NBD_SET_SIZE_BLOCKS, devsize/4096); 70 ioctl(nbd, NBD_CLEAR_SOCK); 71 72 // If the sucker was exported read only, respect that locally. 73 temp = (flags & 2) ? 1 : 0; 74 xioctl(nbd, BLKROSET, &temp); 75 76 if (timeout && ioctl(nbd, NBD_SET_TIMEOUT, timeout)<0) break; 77 if (ioctl(nbd, NBD_SET_SOCK, sock) < 0) break; 78 79 if (toys.optflags & FLAG_s) mlockall(MCL_CURRENT|MCL_FUTURE); 80 81 // Open the device to force reread of the partition table. 82 if ((toys.optflags & FLAG_n) || !xfork()) { 83 char *s = strrchr(device, '/'); 84 int i; 85 86 sprintf(toybuf, "/sys/block/%.32s/pid", s ? s+1 : device); 87 // Is it up yet? (Give it 10 seconds.) 88 for (i=0; i<100; i++) { 89 temp = open(toybuf, O_RDONLY); 90 if (temp == -1) msleep(100); 91 else { 92 close(temp); 93 break; 94 } 95 } 96 close(open(device, O_RDONLY)); 97 if (!(toys.optflags & FLAG_n)) exit(0); 98 } 99 100 // Daemonize here. 101 102 if (daemon(0,0)) perror_exit("daemonize"); 103 104 // Process NBD requests until further notice. 105 106 if (ioctl(nbd, NBD_DO_IT)>=0 || errno==EBADR) break; 107 close(sock); 108 } 109 110 // Flush queue and exit. 111 ioctl(nbd, NBD_CLEAR_QUE); 112 ioctl(nbd, NBD_CLEAR_SOCK); 113 if (CFG_TOYBOX_FREE) close(nbd); 114} 115