| /* |
| * Copyright 2010 Rob Landley <rob@landley.net> |
| * |
| * Licensed under GPLv2, see file LICENSE in this source tree. |
| */ |
| #include "libbb.h" |
| #include <netinet/tcp.h> |
| #include <linux/fs.h> |
| |
| //applet:IF_NBDCLIENT(APPLET_ODDNAME(nbd-client, nbdclient, BB_DIR_USR_SBIN, BB_SUID_DROP, nbdclient)) |
| |
| //kbuild:lib-$(CONFIG_NBDCLIENT) += nbd-client.o |
| |
| //config:config NBDCLIENT |
| //config: bool "nbd-client" |
| //config: default y |
| //config: help |
| //config: Network block device client |
| |
| #define NBD_SET_SOCK _IO(0xab, 0) |
| #define NBD_SET_BLKSIZE _IO(0xab, 1) |
| #define NBD_SET_SIZE _IO(0xab, 2) |
| #define NBD_DO_IT _IO(0xab, 3) |
| #define NBD_CLEAR_SOCK _IO(0xab, 4) |
| #define NBD_CLEAR_QUEUE _IO(0xab, 5) |
| #define NBD_PRINT_DEBUG _IO(0xab, 6) |
| #define NBD_SET_SIZE_BLOCKS _IO(0xab, 7) |
| #define NBD_DISCONNECT _IO(0xab, 8) |
| #define NBD_SET_TIMEOUT _IO(0xab, 9) |
| |
| //usage:#define nbdclient_trivial_usage |
| //usage: "HOST PORT BLOCKDEV" |
| //usage:#define nbdclient_full_usage "\n\n" |
| //usage: "Connect to HOST and provide a network block device on BLOCKDEV" |
| |
| //TODO: more compat with nbd-client version 2.9.13 - |
| //Usage: nbd-client [bs=blocksize] [timeout=sec] host port nbd_device [-swap] [-persist] [-nofork] |
| //Or : nbd-client -d nbd_device |
| //Or : nbd-client -c nbd_device |
| //Default value for blocksize is 1024 (recommended for ethernet) |
| //Allowed values for blocksize are 512,1024,2048,4096 |
| //Note, that kernel 2.4.2 and older ones do not work correctly with |
| //blocksizes other than 1024 without patches |
| |
| int nbdclient_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int nbdclient_main(int argc, char **argv) |
| { |
| unsigned long timeout = 0; |
| #if BB_MMU |
| int nofork = 0; |
| #endif |
| char *host, *port, *device; |
| struct nbd_header_t { |
| uint64_t magic1; // "NBDMAGIC" |
| uint64_t magic2; // 0x420281861253 big endian |
| uint64_t devsize; |
| uint32_t flags; |
| char data[124]; |
| } nbd_header; |
| |
| BUILD_BUG_ON(offsetof(struct nbd_header_t, data) != 8+8+8+4); |
| |
| // Parse command line stuff (just a stub now) |
| if (argc != 4) |
| bb_show_usage(); |
| |
| #if !BB_MMU |
| bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv); |
| #endif |
| |
| host = argv[1]; |
| port = argv[2]; |
| device = argv[3]; |
| |
| // Repeat until spanked (-persist behavior) |
| for (;;) { |
| int sock, nbd; |
| int ro; |
| |
| // Make sure the /dev/nbd exists |
| nbd = xopen(device, O_RDWR); |
| |
| // Find and connect to server |
| sock = create_and_connect_stream_or_die(host, xatou16(port)); |
| setsockopt_1(sock, IPPROTO_TCP, TCP_NODELAY); |
| |
| // Log on to the server |
| xread(sock, &nbd_header, 8+8+8+4 + 124); |
| if (memcmp(&nbd_header.magic1, "NBDMAGIC""\x00\x00\x42\x02\x81\x86\x12\x53", 16) != 0) |
| bb_error_msg_and_die("login failed"); |
| |
| // Set 4k block size. Everything uses that these days |
| ioctl(nbd, NBD_SET_BLKSIZE, 4096); |
| ioctl(nbd, NBD_SET_SIZE_BLOCKS, SWAP_BE64(nbd_header.devsize) / 4096); |
| ioctl(nbd, NBD_CLEAR_SOCK); |
| |
| // If the sucker was exported read only, respect that locally |
| ro = (nbd_header.flags & SWAP_BE32(2)) / SWAP_BE32(2); |
| if (ioctl(nbd, BLKROSET, &ro) < 0) |
| bb_perror_msg_and_die("BLKROSET"); |
| |
| if (timeout) |
| if (ioctl(nbd, NBD_SET_TIMEOUT, timeout)) |
| bb_perror_msg_and_die("NBD_SET_TIMEOUT"); |
| if (ioctl(nbd, NBD_SET_SOCK, sock)) |
| bb_perror_msg_and_die("NBD_SET_SOCK"); |
| |
| // if (swap) mlockall(MCL_CURRENT|MCL_FUTURE); |
| |
| #if BB_MMU |
| // Open the device to force reread of the partition table. |
| // Need to do it in a separate process, since open(device) |
| // needs some other process to sit in ioctl(nbd, NBD_DO_IT). |
| if (fork() == 0) { |
| char *s = strrchr(device, '/'); |
| sprintf(nbd_header.data, "/sys/block/%.32s/pid", s ? s + 1 : device); |
| // Is it up yet? |
| for (;;) { |
| int fd = open(nbd_header.data, O_RDONLY); |
| if (fd >= 0) { |
| //close(fd); |
| break; |
| } |
| sleep(1); |
| } |
| open(device, O_RDONLY); |
| return 0; |
| } |
| |
| // Daemonize here |
| if (!nofork) { |
| daemon(0, 0); |
| nofork = 1; |
| } |
| #endif |
| |
| // This turns us (the process that calls this ioctl) |
| // into a dedicated NBD request handler. |
| // We block here for a long time. |
| // When exactly ioctl returns? On a signal, |
| // or if someone does ioctl(NBD_DISCONNECT) [nbd-client -d]. |
| if (ioctl(nbd, NBD_DO_IT) >= 0 || errno == EBADR) { |
| // Flush queue and exit |
| ioctl(nbd, NBD_CLEAR_QUEUE); |
| ioctl(nbd, NBD_CLEAR_SOCK); |
| break; |
| } |
| |
| close(sock); |
| close(nbd); |
| } |
| |
| return 0; |
| } |