/* 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" 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; struct addrinfo *addr, *p; 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; struct addrinfo hints; // Find and connect to server memset(&hints, 0, sizeof(hints)); hints.ai_family = PF_UNSPEC; hints.ai_socktype = SOCK_STREAM; if (getaddrinfo(host, port, &hints, &addr)) addr = 0; for (p = addr; p; p = p->ai_next) { sock = socket(p->ai_family, p->ai_socktype, p->ai_protocol); if (-1 != connect(sock, p->ai_addr, p->ai_addrlen)) break; close(sock); } freeaddrinfo(addr); if (!p) perror_exit("%s:%s", host, port); 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); }