/* * Copyright (C) 2005 Anthony Liguori * * Network Block Device * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; under version 2 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . */ #include #include "block_int.h" #include "nbd.h" #include #include #include #include #include #include #include #include #include #include #include #define SOCKET_PATH "/var/lock/qemu-nbd-%s" #define NBD_BUFFER_SIZE (1024*1024) static int verbose; static void usage(const char *name) { printf( "Usage: %s [OPTIONS] FILE\n" "QEMU Disk Network Block Device Server\n" "\n" " -p, --port=PORT port to listen on (default `%d')\n" " -o, --offset=OFFSET offset into the image\n" " -b, --bind=IFACE interface to bind to (default `0.0.0.0')\n" " -k, --socket=PATH path to the unix socket\n" " (default '"SOCKET_PATH"')\n" " -r, --read-only export read-only\n" " -P, --partition=NUM only expose partition NUM\n" " -s, --snapshot use snapshot file\n" " -n, --nocache disable host cache\n" " -c, --connect=DEV connect FILE to the local NBD device DEV\n" " -d, --disconnect disconnect the specified device\n" " -e, --shared=NUM device can be shared by NUM clients (default '1')\n" " -t, --persistent don't exit on the last connection\n" " -v, --verbose display extra debugging information\n" " -h, --help display this help and exit\n" " -V, --version output version information and exit\n" "\n" "Report bugs to \n" , name, NBD_DEFAULT_PORT, "DEVICE"); } static void version(const char *name) { printf( "%s version 0.0.1\n" "Written by Anthony Liguori.\n" "\n" "Copyright (C) 2006 Anthony Liguori .\n" "This is free software; see the source for copying conditions. There is NO\n" "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n" , name); } struct partition_record { uint8_t bootable; uint8_t start_head; uint32_t start_cylinder; uint8_t start_sector; uint8_t system; uint8_t end_head; uint8_t end_cylinder; uint8_t end_sector; uint32_t start_sector_abs; uint32_t nb_sectors_abs; }; static void read_partition(uint8_t *p, struct partition_record *r) { r->bootable = p[0]; r->start_head = p[1]; r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300); r->start_sector = p[2] & 0x3f; r->system = p[4]; r->end_head = p[5]; r->end_cylinder = p[7] | ((p[6] << 2) & 0x300); r->end_sector = p[6] & 0x3f; r->start_sector_abs = p[8] | p[9] << 8 | p[10] << 16 | p[11] << 24; r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24; } static int find_partition(BlockDriverState *bs, int partition, off_t *offset, off_t *size) { struct partition_record mbr[4]; uint8_t data[512]; int i; int ext_partnum = 4; int ret; if ((ret = bdrv_read(bs, 0, data, 1)) < 0) { errno = -ret; err(EXIT_FAILURE, "error while reading"); } if (data[510] != 0x55 || data[511] != 0xaa) { errno = -EINVAL; return -1; } for (i = 0; i < 4; i++) { read_partition(&data[446 + 16 * i], &mbr[i]); if (!mbr[i].nb_sectors_abs) continue; if (mbr[i].system == 0xF || mbr[i].system == 0x5) { struct partition_record ext[4]; uint8_t data1[512]; int j; if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) { errno = -ret; err(EXIT_FAILURE, "error while reading"); } for (j = 0; j < 4; j++) { read_partition(&data1[446 + 16 * j], &ext[j]); if (!ext[j].nb_sectors_abs) continue; if ((ext_partnum + j + 1) == partition) { *offset = (uint64_t)ext[j].start_sector_abs << 9; *size = (uint64_t)ext[j].nb_sectors_abs << 9; return 0; } } ext_partnum += 4; } else if ((i + 1) == partition) { *offset = (uint64_t)mbr[i].start_sector_abs << 9; *size = (uint64_t)mbr[i].nb_sectors_abs << 9; return 0; } } errno = -ENOENT; return -1; } static void show_parts(const char *device) { if (fork() == 0) { int nbd; /* linux just needs an open() to trigger * the partition table update * but remember to load the module with max_part != 0 : * modprobe nbd max_part=63 */ nbd = open(device, O_RDWR); if (nbd != -1) close(nbd); exit(0); } } int main(int argc, char **argv) { BlockDriverState *bs; off_t dev_offset = 0; off_t offset = 0; bool readonly = false; bool disconnect = false; const char *bindto = "0.0.0.0"; int port = NBD_DEFAULT_PORT; struct sockaddr_in addr; socklen_t addr_len = sizeof(addr); off_t fd_size; char *device = NULL; char *socket = NULL; char sockpath[128]; const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t"; struct option lopt[] = { { "help", 0, NULL, 'h' }, { "version", 0, NULL, 'V' }, { "bind", 1, NULL, 'b' }, { "port", 1, NULL, 'p' }, { "socket", 1, NULL, 'k' }, { "offset", 1, NULL, 'o' }, { "read-only", 0, NULL, 'r' }, { "partition", 1, NULL, 'P' }, { "connect", 1, NULL, 'c' }, { "disconnect", 0, NULL, 'd' }, { "snapshot", 0, NULL, 's' }, { "nocache", 0, NULL, 'n' }, { "shared", 1, NULL, 'e' }, { "persistent", 0, NULL, 't' }, { "verbose", 0, NULL, 'v' }, { NULL, 0, NULL, 0 } }; int ch; int opt_ind = 0; int li; char *end; int flags = BDRV_O_RDWR; int partition = -1; int ret; int shared = 1; uint8_t *data; fd_set fds; int *sharing_fds; int fd; int i; int nb_fds = 0; int max_fd; int persistent = 0; uint32_t nbdflags; while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) { switch (ch) { case 's': flags |= BDRV_O_SNAPSHOT; break; case 'n': flags |= BDRV_O_NOCACHE; break; case 'b': bindto = optarg; break; case 'p': li = strtol(optarg, &end, 0); if (*end) { errx(EXIT_FAILURE, "Invalid port `%s'", optarg); } if (li < 1 || li > 65535) { errx(EXIT_FAILURE, "Port out of range `%s'", optarg); } port = (uint16_t)li; break; case 'o': dev_offset = strtoll (optarg, &end, 0); if (*end) { errx(EXIT_FAILURE, "Invalid offset `%s'", optarg); } if (dev_offset < 0) { errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg); } break; case 'r': readonly = true; flags &= ~BDRV_O_RDWR; break; case 'P': partition = strtol(optarg, &end, 0); if (*end) errx(EXIT_FAILURE, "Invalid partition `%s'", optarg); if (partition < 1 || partition > 8) errx(EXIT_FAILURE, "Invalid partition %d", partition); break; case 'k': socket = optarg; if (socket[0] != '/') errx(EXIT_FAILURE, "socket path must be absolute\n"); break; case 'd': disconnect = true; break; case 'c': device = optarg; break; case 'e': shared = strtol(optarg, &end, 0); if (*end) { errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg); } if (shared < 1) { errx(EXIT_FAILURE, "Shared device number must be greater than 0\n"); } break; case 't': persistent = 1; break; case 'v': verbose = 1; break; case 'V': version(argv[0]); exit(0); break; case 'h': usage(argv[0]); exit(0); break; case '?': errx(EXIT_FAILURE, "Try `%s --help' for more information.", argv[0]); } } if ((argc - optind) != 1) { errx(EXIT_FAILURE, "Invalid number of argument.\n" "Try `%s --help' for more information.", argv[0]); } if (disconnect) { fd = open(argv[optind], O_RDWR); if (fd == -1) err(EXIT_FAILURE, "Cannot open %s", argv[optind]); nbd_disconnect(fd); close(fd); printf("%s disconnected\n", argv[optind]); return 0; } bdrv_init(); bs = bdrv_new("hda"); if (bs == NULL) return 1; if ((ret = bdrv_open(bs, argv[optind], flags, NULL)) < 0) { errno = -ret; err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]); } fd_size = bs->total_sectors * 512; if (partition != -1 && find_partition(bs, partition, &dev_offset, &fd_size)) err(EXIT_FAILURE, "Could not find partition %d", partition); if (device) { pid_t pid; int sock; /* want to fail before daemonizing */ if (access(device, R_OK|W_OK) == -1) { err(EXIT_FAILURE, "Could not access '%s'", device); } if (!verbose) { /* detach client and server */ if (daemon(0, 0) == -1) { err(EXIT_FAILURE, "Failed to daemonize"); } } if (socket == NULL) { snprintf(sockpath, sizeof(sockpath), SOCKET_PATH, basename(device)); socket = sockpath; } pid = fork(); if (pid < 0) return 1; if (pid != 0) { off_t size; size_t blocksize; ret = 0; bdrv_close(bs); do { sock = unix_socket_outgoing(socket); if (sock == -1) { if (errno != ENOENT && errno != ECONNREFUSED) { ret = 1; goto out; } sleep(1); /* wait children */ } } while (sock == -1); fd = open(device, O_RDWR); if (fd == -1) { ret = 1; goto out; } ret = nbd_receive_negotiate(sock, NULL, &nbdflags, &size, &blocksize); if (ret == -1) { ret = 1; goto out; } ret = nbd_init(fd, sock, size, blocksize); if (ret == -1) { ret = 1; goto out; } printf("NBD device %s is now connected to file %s\n", device, argv[optind]); /* update partition table */ show_parts(device); ret = nbd_client(fd); if (ret) { ret = 1; } close(fd); out: kill(pid, SIGTERM); unlink(socket); return ret; } /* children */ } sharing_fds = qemu_malloc((shared + 1) * sizeof(int)); if (socket) { sharing_fds[0] = unix_socket_incoming(socket); } else { sharing_fds[0] = tcp_socket_incoming(bindto, port); } if (sharing_fds[0] == -1) return 1; max_fd = sharing_fds[0]; nb_fds++; data = qemu_blockalign(bs, NBD_BUFFER_SIZE); if (data == NULL) errx(EXIT_FAILURE, "Cannot allocate data buffer"); do { FD_ZERO(&fds); for (i = 0; i < nb_fds; i++) FD_SET(sharing_fds[i], &fds); ret = select(max_fd + 1, &fds, NULL, NULL, NULL); if (ret == -1) break; if (FD_ISSET(sharing_fds[0], &fds)) ret--; for (i = 1; i < nb_fds && ret; i++) { if (FD_ISSET(sharing_fds[i], &fds)) { if (nbd_trip(bs, sharing_fds[i], fd_size, dev_offset, &offset, readonly, data, NBD_BUFFER_SIZE) != 0) { close(sharing_fds[i]); nb_fds--; sharing_fds[i] = sharing_fds[nb_fds]; i--; } ret--; } } /* new connection ? */ if (FD_ISSET(sharing_fds[0], &fds)) { if (nb_fds < shared + 1) { sharing_fds[nb_fds] = accept(sharing_fds[0], (struct sockaddr *)&addr, &addr_len); if (sharing_fds[nb_fds] != -1 && nbd_negotiate(sharing_fds[nb_fds], fd_size) != -1) { if (sharing_fds[nb_fds] > max_fd) max_fd = sharing_fds[nb_fds]; nb_fds++; } } } } while (persistent || nb_fds > 1); qemu_vfree(data); close(sharing_fds[0]); bdrv_close(bs); qemu_free(sharing_fds); if (socket) unlink(socket); return 0; }