diff options
| -rw-r--r-- | toys/other/nbd_client.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/toys/other/nbd_client.c b/toys/other/nbd_client.c new file mode 100644 index 00000000..33787d77 --- /dev/null +++ b/toys/other/nbd_client.c @@ -0,0 +1,128 @@ +/* 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, OPTSTR_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. + + daemon(0,0); + + // Process NBD requests until further notice. + + if (ioctl(nbd, NBD_DO_IT)>=0 || errno==EBADR) break; + close(sock); + } + close(nbd); + + // Flush queue and exit. + + ioctl(nbd, NBD_CLEAR_QUE); + ioctl(nbd, NBD_CLEAR_SOCK); +} |