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nbd-client: new applet
function old new delta nbdclient_main - 537 +537 daemon - 162 +162 packed_usage 27682 27724 +42 applet_names 2355 2366 +11 bbconfig_config_bz2 4918 4922 +4 applet_main 1376 1380 +4 applet_nameofs 688 690 +2 applet_install_loc 172 173 +1 ------------------------------------------------------------------------------ (add/remove: 4/0 grow/shrink: 6/0 up/down: 763/0) Total: 763 bytes Signed-off-by: Rob Landley <rob@landley.net> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Rob Landley
Denys Vlasenko
parent
361b1a6884
commit
1fc20c446f
153
networking/nbd-client.c
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153
networking/nbd-client.c
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/*
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* Copyright 2010 Rob Landley <rob@landley.net>
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*
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* Licensed under GPLv2, see file LICENSE in this source tree.
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*/
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#include "libbb.h"
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#include <netinet/tcp.h>
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#include <linux/fs.h>
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//applet:IF_NBDCLIENT(APPLET_ODDNAME(nbd-client, nbdclient, _BB_DIR_USR_SBIN, _BB_SUID_DROP, nbdclient))
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//kbuild:lib-$(CONFIG_NBDCLIENT) += nbd-client.o
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//config:config NBDCLIENT
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//config: bool "nbd-client"
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//config: default y
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//config: help
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//config: Network block device client
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#define NBD_SET_SOCK _IO(0xab, 0)
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#define NBD_SET_BLKSIZE _IO(0xab, 1)
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#define NBD_SET_SIZE _IO(0xab, 2)
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#define NBD_DO_IT _IO(0xab, 3)
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#define NBD_CLEAR_SOCK _IO(0xab, 4)
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#define NBD_CLEAR_QUEUE _IO(0xab, 5)
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#define NBD_PRINT_DEBUG _IO(0xab, 6)
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#define NBD_SET_SIZE_BLOCKS _IO(0xab, 7)
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#define NBD_DISCONNECT _IO(0xab, 8)
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#define NBD_SET_TIMEOUT _IO(0xab, 9)
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//usage:#define nbdclient_trivial_usage
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//usage: "HOST PORT BLOCKDEV"
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//usage:#define nbdclient_full_usage "\n\n"
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//usage: "Connect to HOST and provide a network block device on BLOCKDEV"
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//TODO: more compat with nbd-client version 2.9.13 -
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//Usage: nbd-client [bs=blocksize] [timeout=sec] host port nbd_device [-swap] [-persist] [-nofork]
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//Or : nbd-client -d nbd_device
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//Or : nbd-client -c nbd_device
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//Default value for blocksize is 1024 (recommended for ethernet)
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//Allowed values for blocksize are 512,1024,2048,4096
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//Note, that kernel 2.4.2 and older ones do not work correctly with
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//blocksizes other than 1024 without patches
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int nbdclient_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int nbdclient_main(int argc, char **argv)
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{
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unsigned long timeout = 0;
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int nofork = 0;
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char *host, *port, *device;
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struct nbd_header_t {
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uint64_t magic1; // "NBDMAGIC"
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uint64_t magic2; // 0x420281861253 big endian
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uint64_t devsize;
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uint32_t flags;
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char data[124];
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} nbd_header;
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struct bug_check {
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char c[offsetof(struct nbd_header_t, data) == 8+8+8+4 ? 1 : -1];
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};
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// Parse command line stuff (just a stub now)
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if (argc != 4)
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bb_show_usage();
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#if !BB_MMU
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bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv);
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#endif
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host = argv[1];
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port = argv[2];
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device = argv[3];
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// Repeat until spanked (-persist behavior)
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for (;;) {
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int sock, nbd;
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int ro;
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// Make sure the /dev/nbd exists
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nbd = xopen(device, O_RDWR);
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// Find and connect to server
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sock = create_and_connect_stream_or_die(host, xatou16(port));
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setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &const_int_1, sizeof(const_int_1));
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// Log on to the server
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xread(sock, &nbd_header, 8+8+8+4 + 124);
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if (memcmp(&nbd_header.magic1, "NBDMAGIC""\x00\x00\x42\x02\x81\x86\x12\x53", 16) != 0)
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bb_error_msg_and_die("login failed");
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// Set 4k block size. Everything uses that these days
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ioctl(nbd, NBD_SET_BLKSIZE, 4096);
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ioctl(nbd, NBD_SET_SIZE_BLOCKS, SWAP_BE64(nbd_header.devsize) / 4096);
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ioctl(nbd, NBD_CLEAR_SOCK);
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// If the sucker was exported read only, respect that locally
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ro = (nbd_header.flags & SWAP_BE32(2)) / SWAP_BE32(2);
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if (ioctl(nbd, BLKROSET, &ro) < 0)
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bb_perror_msg_and_die("BLKROSET");
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if (timeout)
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if (ioctl(nbd, NBD_SET_TIMEOUT, timeout))
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bb_perror_msg_and_die("NBD_SET_TIMEOUT");
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if (ioctl(nbd, NBD_SET_SOCK, sock))
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bb_perror_msg_and_die("NBD_SET_SOCK");
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// if (swap) mlockall(MCL_CURRENT|MCL_FUTURE);
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#if BB_MMU
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// Open the device to force reread of the partition table.
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// Need to do it in a separate process, since open(device)
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// needs some other process to sit in ioctl(nbd, NBD_DO_IT).
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if (fork() == 0) {
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char *s = strrchr(device, '/');
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sprintf(nbd_header.data, "/sys/block/%.32s/pid", s ? s + 1 : device);
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// Is it up yet?
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for (;;) {
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int fd = open(nbd_header.data, O_RDONLY);
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if (fd >= 0) {
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//close(fd);
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break;
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}
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sleep(1);
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}
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open(device, O_RDONLY);
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return 0;
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}
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// Daemonize here
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if (!nofork) {
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daemon(0, 0);
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nofork = 1;
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}
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#endif
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// This turns us (the process that calls this ioctl)
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// into a dedicated NBD request handler.
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// We block here for a long time.
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// When exactly ioctl returns? On a signal,
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// or if someone does ioctl(NBD_DISCONNECT) [nbd-client -d].
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if (ioctl(nbd, NBD_DO_IT) >= 0 || errno == EBADR) {
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// Flush queue and exit
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ioctl(nbd, NBD_CLEAR_QUEUE);
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ioctl(nbd, NBD_CLEAR_SOCK);
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break;
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}
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close(sock);
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close(nbd);
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}
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return 0;
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}
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