/* * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> * * 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 <http://www.gnu.org/licenses/>. */ #include "qemu-common.h" #include "sysemu/block-backend.h" #include "block/block_int.h" #include "block/nbd.h" #include "qemu/main-loop.h" #include "qemu/sockets.h" #include "qemu/error-report.h" #include "block/snapshot.h" #include "qapi/util.h" #include "qapi/qmp/qstring.h" #include <stdarg.h> #include <stdio.h> #include <getopt.h> #include <err.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <netinet/tcp.h> #include <arpa/inet.h> #include <signal.h> #include <libgen.h> #include <pthread.h> #define SOCKET_PATH "/var/lock/qemu-nbd-%s" #define QEMU_NBD_OPT_CACHE 1 #define QEMU_NBD_OPT_AIO 2 #define QEMU_NBD_OPT_DISCARD 3 #define QEMU_NBD_OPT_DETECT_ZEROES 4 static NBDExport *exp; static int verbose; static char *srcpath; static SocketAddress *saddr; static int persistent = 0; static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state; static int shared = 1; static int nb_fds; static int server_fd; static void usage(const char *name) { (printf) ( "Usage: %s [OPTIONS] FILE\n" "QEMU Disk Network Block Device Server\n" "\n" " -h, --help display this help and exit\n" " -V, --version output version information and exit\n" "\n" "Connection properties:\n" " -p, --port=PORT port to listen on (default `%d')\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" " -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" "\n" "Exposing part of the image:\n" " -o, --offset=OFFSET offset into the image\n" " -P, --partition=NUM only expose partition NUM\n" "\n" #ifdef __linux__ "Kernel NBD client support:\n" " -c, --connect=DEV connect FILE to the local NBD device DEV\n" " -d, --disconnect disconnect the specified device\n" "\n" #endif "\n" "Block device options:\n" " -f, --format=FORMAT set image format (raw, qcow2, ...)\n" " -r, --read-only export read-only\n" " -s, --snapshot use FILE as an external snapshot, create a temporary\n" " file with backing_file=FILE, redirect the write to\n" " the temporary one\n" " -l, --load-snapshot=SNAPSHOT_PARAM\n" " load an internal snapshot inside FILE and export it\n" " as an read-only device, SNAPSHOT_PARAM format is\n" " 'snapshot.id=[ID],snapshot.name=[NAME]', or\n" " '[ID_OR_NAME]'\n" " -n, --nocache disable host cache\n" " --cache=MODE set cache mode (none, writeback, ...)\n" #ifdef CONFIG_LINUX_AIO " --aio=MODE set AIO mode (native or threads)\n" #endif " --discard=MODE set discard mode (ignore, unmap)\n" " --detect-zeroes=MODE set detect-zeroes mode (off, on, unmap)\n" "\n" "Report bugs to <qemu-devel@nongnu.org>\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 <anthony@codemonkey.ws>.\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 = le32_to_cpup((uint32_t *)(p + 8)); r->nb_sectors_abs = le32_to_cpup((uint32_t *)(p + 12)); } static int find_partition(BlockBackend *blk, 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 = blk_read(blk, 0, data, 1)) < 0) { errno = -ret; err(EXIT_FAILURE, "error while reading"); } if (data[510] != 0x55 || data[511] != 0xaa) { return -EINVAL; } for (i = 0; i < 4; i++) { read_partition(&data[446 + 16 * i], &mbr[i]); if (!mbr[i].system || !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 = blk_read(blk, 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].system || !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; } } return -ENOENT; } static void termsig_handler(int signum) { state = TERMINATE; qemu_notify_event(); } static void *show_parts(void *arg) { char *device = arg; 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 >= 0) { close(nbd); } return NULL; } static void *nbd_client_thread(void *arg) { char *device = arg; off_t size; uint32_t nbdflags; int fd, sock; int ret; pthread_t show_parts_thread; Error *local_error = NULL; sock = socket_connect(saddr, &local_error, NULL, NULL); if (sock < 0) { error_report_err(local_error); goto out; } ret = nbd_receive_negotiate(sock, NULL, &nbdflags, &size, &local_error); if (ret < 0) { if (local_error) { fprintf(stderr, "%s\n", error_get_pretty(local_error)); error_free(local_error); } goto out_socket; } fd = open(device, O_RDWR); if (fd < 0) { /* Linux-only, we can use %m in printf. */ fprintf(stderr, "Failed to open %s: %m\n", device); goto out_socket; } ret = nbd_init(fd, sock, nbdflags, size); if (ret < 0) { goto out_fd; } /* update partition table */ pthread_create(&show_parts_thread, NULL, show_parts, device); if (verbose) { fprintf(stderr, "NBD device %s is now connected to %s\n", device, srcpath); } else { /* Close stderr so that the qemu-nbd process exits. */ dup2(STDOUT_FILENO, STDERR_FILENO); } ret = nbd_client(fd); if (ret) { goto out_fd; } close(fd); kill(getpid(), SIGTERM); return (void *) EXIT_SUCCESS; out_fd: close(fd); out_socket: closesocket(sock); out: kill(getpid(), SIGTERM); return (void *) EXIT_FAILURE; } static int nbd_can_accept(void) { return nb_fds < shared; } static void nbd_export_closed(NBDExport *exp) { assert(state == TERMINATING); state = TERMINATED; } static void nbd_update_server_fd_handler(int fd); static void nbd_client_closed(NBDClient *client) { nb_fds--; if (nb_fds == 0 && !persistent && state == RUNNING) { state = TERMINATE; } nbd_update_server_fd_handler(server_fd); nbd_client_put(client); } static void nbd_accept(void *opaque) { struct sockaddr_in addr; socklen_t addr_len = sizeof(addr); int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len); if (fd < 0) { perror("accept"); return; } if (state >= TERMINATE) { close(fd); return; } if (nbd_client_new(exp, fd, nbd_client_closed)) { nb_fds++; nbd_update_server_fd_handler(server_fd); } else { shutdown(fd, 2); close(fd); } } static void nbd_update_server_fd_handler(int fd) { if (nbd_can_accept()) { qemu_set_fd_handler(fd, nbd_accept, NULL, (void *)(uintptr_t)fd); } else { qemu_set_fd_handler(fd, NULL, NULL, NULL); } } static SocketAddress *nbd_build_socket_address(const char *sockpath, const char *bindto, const char *port) { SocketAddress *saddr; saddr = g_new0(SocketAddress, 1); if (sockpath) { saddr->kind = SOCKET_ADDRESS_KIND_UNIX; saddr->q_unix = g_new0(UnixSocketAddress, 1); saddr->q_unix->path = g_strdup(sockpath); } else { saddr->kind = SOCKET_ADDRESS_KIND_INET; saddr->inet = g_new0(InetSocketAddress, 1); saddr->inet->host = g_strdup(bindto); if (port) { saddr->inet->port = g_strdup(port); } else { saddr->inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT); } } return saddr; } int main(int argc, char **argv) { BlockBackend *blk; BlockDriverState *bs; off_t dev_offset = 0; uint32_t nbdflags = 0; bool disconnect = false; const char *bindto = "0.0.0.0"; const char *port = NULL; char *sockpath = NULL; char *device = NULL; off_t fd_size; QemuOpts *sn_opts = NULL; const char *sn_id_or_name = NULL; const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:"; 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' }, { "load-snapshot", 1, NULL, 'l' }, { "nocache", 0, NULL, 'n' }, { "cache", 1, NULL, QEMU_NBD_OPT_CACHE }, #ifdef CONFIG_LINUX_AIO { "aio", 1, NULL, QEMU_NBD_OPT_AIO }, #endif { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD }, { "detect-zeroes", 1, NULL, QEMU_NBD_OPT_DETECT_ZEROES }, { "shared", 1, NULL, 'e' }, { "format", 1, NULL, 'f' }, { "persistent", 0, NULL, 't' }, { "verbose", 0, NULL, 'v' }, { NULL, 0, NULL, 0 } }; int ch; int opt_ind = 0; char *end; int flags = BDRV_O_RDWR; int partition = -1; int ret = 0; int fd; bool seen_cache = false; bool seen_discard = false; #ifdef CONFIG_LINUX_AIO bool seen_aio = false; #endif pthread_t client_thread; const char *fmt = NULL; Error *local_err = NULL; BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF; QDict *options = NULL; /* The client thread uses SIGTERM to interrupt the server. A signal * handler ensures that "qemu-nbd -v -c" exits with a nice status code. */ struct sigaction sa_sigterm; memset(&sa_sigterm, 0, sizeof(sa_sigterm)); sa_sigterm.sa_handler = termsig_handler; sigaction(SIGTERM, &sa_sigterm, NULL); qemu_init_exec_dir(argv[0]); while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) { switch (ch) { case 's': flags |= BDRV_O_SNAPSHOT; break; case 'n': optarg = (char *) "none"; /* fallthrough */ case QEMU_NBD_OPT_CACHE: if (seen_cache) { errx(EXIT_FAILURE, "-n and --cache can only be specified once"); } seen_cache = true; if (bdrv_parse_cache_flags(optarg, &flags) == -1) { errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg); } break; #ifdef CONFIG_LINUX_AIO case QEMU_NBD_OPT_AIO: if (seen_aio) { errx(EXIT_FAILURE, "--aio can only be specified once"); } seen_aio = true; if (!strcmp(optarg, "native")) { flags |= BDRV_O_NATIVE_AIO; } else if (!strcmp(optarg, "threads")) { /* this is the default */ } else { errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg); } break; #endif case QEMU_NBD_OPT_DISCARD: if (seen_discard) { errx(EXIT_FAILURE, "--discard can only be specified once"); } seen_discard = true; if (bdrv_parse_discard_flags(optarg, &flags) == -1) { errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg); } break; case QEMU_NBD_OPT_DETECT_ZEROES: detect_zeroes = qapi_enum_parse(BlockdevDetectZeroesOptions_lookup, optarg, BLOCKDEV_DETECT_ZEROES_OPTIONS_MAX, BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF, &local_err); if (local_err) { errx(EXIT_FAILURE, "Failed to parse detect_zeroes mode: %s", error_get_pretty(local_err)); } if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP && !(flags & BDRV_O_UNMAP)) { errx(EXIT_FAILURE, "setting detect-zeroes to unmap is not allowed " "without setting discard operation to unmap"); } break; case 'b': bindto = optarg; break; case 'p': port = optarg; 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 'l': if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) { sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts, optarg, false); if (!sn_opts) { errx(EXIT_FAILURE, "Failed in parsing snapshot param `%s'", optarg); } } else { sn_id_or_name = optarg; } /* fall through */ case 'r': nbdflags |= NBD_FLAG_READ_ONLY; 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': sockpath = optarg; if (sockpath[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 'f': fmt = optarg; 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 < 0) { err(EXIT_FAILURE, "Cannot open %s", argv[optind]); } nbd_disconnect(fd); close(fd); printf("%s disconnected\n", argv[optind]); return 0; } if (device && !verbose) { int stderr_fd[2]; pid_t pid; int ret; if (qemu_pipe(stderr_fd) < 0) { err(EXIT_FAILURE, "Error setting up communication pipe"); } /* Now daemonize, but keep a communication channel open to * print errors and exit with the proper status code. */ pid = fork(); if (pid < 0) { err(EXIT_FAILURE, "Failed to fork"); } else if (pid == 0) { close(stderr_fd[0]); ret = qemu_daemon(1, 0); /* Temporarily redirect stderr to the parent's pipe... */ dup2(stderr_fd[1], STDERR_FILENO); if (ret < 0) { err(EXIT_FAILURE, "Failed to daemonize"); } /* ... close the descriptor we inherited and go on. */ close(stderr_fd[1]); } else { bool errors = false; char *buf; /* In the parent. Print error messages from the child until * it closes the pipe. */ close(stderr_fd[1]); buf = g_malloc(1024); while ((ret = read(stderr_fd[0], buf, 1024)) > 0) { errors = true; ret = qemu_write_full(STDERR_FILENO, buf, ret); if (ret < 0) { exit(EXIT_FAILURE); } } if (ret < 0) { err(EXIT_FAILURE, "Cannot read from daemon"); } /* Usually the daemon should not print any message. * Exit with zero status in that case. */ exit(errors); } } if (device != NULL && sockpath == NULL) { sockpath = g_malloc(128); snprintf(sockpath, 128, SOCKET_PATH, basename(device)); } saddr = nbd_build_socket_address(sockpath, bindto, port); if (qemu_init_main_loop(&local_err)) { error_report_err(local_err); exit(EXIT_FAILURE); } bdrv_init(); atexit(bdrv_close_all); if (fmt) { options = qdict_new(); qdict_put(options, "driver", qstring_from_str(fmt)); } srcpath = argv[optind]; blk = blk_new_open("hda", srcpath, NULL, options, flags, &local_err); if (!blk) { errx(EXIT_FAILURE, "Failed to blk_new_open '%s': %s", argv[optind], error_get_pretty(local_err)); } bs = blk_bs(blk); if (sn_opts) { ret = bdrv_snapshot_load_tmp(bs, qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID), qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME), &local_err); } else if (sn_id_or_name) { ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name, &local_err); } if (ret < 0) { errno = -ret; err(EXIT_FAILURE, "Failed to load snapshot: %s", error_get_pretty(local_err)); } bs->detect_zeroes = detect_zeroes; fd_size = blk_getlength(blk); if (fd_size < 0) { errx(EXIT_FAILURE, "Failed to determine the image length: %s", strerror(-fd_size)); } if (partition != -1) { ret = find_partition(blk, partition, &dev_offset, &fd_size); if (ret < 0) { errno = -ret; err(EXIT_FAILURE, "Could not find partition %d", partition); } } exp = nbd_export_new(blk, dev_offset, fd_size, nbdflags, nbd_export_closed, &local_err); if (!exp) { errx(EXIT_FAILURE, "%s", error_get_pretty(local_err)); } fd = socket_listen(saddr, &local_err); if (fd < 0) { error_report_err(local_err); return 1; } if (device) { int ret; ret = pthread_create(&client_thread, NULL, nbd_client_thread, device); if (ret != 0) { errx(EXIT_FAILURE, "Failed to create client thread: %s", strerror(ret)); } } else { /* Shut up GCC warnings. */ memset(&client_thread, 0, sizeof(client_thread)); } server_fd = fd; nbd_update_server_fd_handler(fd); /* now when the initialization is (almost) complete, chdir("/") * to free any busy filesystems */ if (chdir("/") < 0) { err(EXIT_FAILURE, "Could not chdir to root directory"); } state = RUNNING; do { main_loop_wait(false); if (state == TERMINATE) { state = TERMINATING; nbd_export_close(exp); nbd_export_put(exp); exp = NULL; } } while (state != TERMINATED); blk_unref(blk); if (sockpath) { unlink(sockpath); } qemu_opts_del(sn_opts); if (device) { void *ret; pthread_join(client_thread, &ret); exit(ret != NULL); } else { exit(EXIT_SUCCESS); } }