xref: /openbmc/qemu/qemu-nbd.c (revision f173d57a)
1 /*
2  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
3  *
4  *  Network Block Device
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; under version 2 of the License.
9  *
10  *  This program is distributed in the hope that it will be useful,
11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  *  GNU General Public License for more details.
14  *
15  *  You should have received a copy of the GNU General Public License
16  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
17  */
18 
19 #include "qemu-common.h"
20 #include "block/block.h"
21 #include "block/nbd.h"
22 #include "qemu/main-loop.h"
23 #include "qemu/sockets.h"
24 #include "qemu/error-report.h"
25 #include "block/snapshot.h"
26 
27 #include <stdarg.h>
28 #include <stdio.h>
29 #include <getopt.h>
30 #include <err.h>
31 #include <sys/types.h>
32 #include <sys/socket.h>
33 #include <netinet/in.h>
34 #include <netinet/tcp.h>
35 #include <arpa/inet.h>
36 #include <signal.h>
37 #include <libgen.h>
38 #include <pthread.h>
39 
40 #define SOCKET_PATH          "/var/lock/qemu-nbd-%s"
41 #define QEMU_NBD_OPT_CACHE   1
42 #define QEMU_NBD_OPT_AIO     2
43 #define QEMU_NBD_OPT_DISCARD 3
44 
45 static NBDExport *exp;
46 static int verbose;
47 static char *srcpath;
48 static char *sockpath;
49 static int persistent = 0;
50 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
51 static int shared = 1;
52 static int nb_fds;
53 
54 static void usage(const char *name)
55 {
56     (printf) (
57 "Usage: %s [OPTIONS] FILE\n"
58 "QEMU Disk Network Block Device Server\n"
59 "\n"
60 "  -h, --help           display this help and exit\n"
61 "  -V, --version        output version information and exit\n"
62 "\n"
63 "Connection properties:\n"
64 "  -p, --port=PORT      port to listen on (default `%d')\n"
65 "  -b, --bind=IFACE     interface to bind to (default `0.0.0.0')\n"
66 "  -k, --socket=PATH    path to the unix socket\n"
67 "                       (default '"SOCKET_PATH"')\n"
68 "  -e, --shared=NUM     device can be shared by NUM clients (default '1')\n"
69 "  -t, --persistent     don't exit on the last connection\n"
70 "  -v, --verbose        display extra debugging information\n"
71 "\n"
72 "Exposing part of the image:\n"
73 "  -o, --offset=OFFSET  offset into the image\n"
74 "  -P, --partition=NUM  only expose partition NUM\n"
75 "\n"
76 #ifdef __linux__
77 "Kernel NBD client support:\n"
78 "  -c, --connect=DEV    connect FILE to the local NBD device DEV\n"
79 "  -d, --disconnect     disconnect the specified device\n"
80 "\n"
81 #endif
82 "\n"
83 "Block device options:\n"
84 "  -f, --format=FORMAT  set image format (raw, qcow2, ...)\n"
85 "  -r, --read-only      export read-only\n"
86 "  -s, --snapshot       use FILE as an external snapshot, create a temporary\n"
87 "                       file with backing_file=FILE, redirect the write to\n"
88 "                       the temporary one\n"
89 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
90 "                       load an internal snapshot inside FILE and export it\n"
91 "                       as an read-only device, SNAPSHOT_PARAM format is\n"
92 "                       'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
93 "                       '[ID_OR_NAME]'\n"
94 "  -n, --nocache        disable host cache\n"
95 "      --cache=MODE     set cache mode (none, writeback, ...)\n"
96 #ifdef CONFIG_LINUX_AIO
97 "      --aio=MODE       set AIO mode (native or threads)\n"
98 #endif
99 "\n"
100 "Report bugs to <qemu-devel@nongnu.org>\n"
101     , name, NBD_DEFAULT_PORT, "DEVICE");
102 }
103 
104 static void version(const char *name)
105 {
106     printf(
107 "%s version 0.0.1\n"
108 "Written by Anthony Liguori.\n"
109 "\n"
110 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
111 "This is free software; see the source for copying conditions.  There is NO\n"
112 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
113     , name);
114 }
115 
116 struct partition_record
117 {
118     uint8_t bootable;
119     uint8_t start_head;
120     uint32_t start_cylinder;
121     uint8_t start_sector;
122     uint8_t system;
123     uint8_t end_head;
124     uint8_t end_cylinder;
125     uint8_t end_sector;
126     uint32_t start_sector_abs;
127     uint32_t nb_sectors_abs;
128 };
129 
130 static void read_partition(uint8_t *p, struct partition_record *r)
131 {
132     r->bootable = p[0];
133     r->start_head = p[1];
134     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
135     r->start_sector = p[2] & 0x3f;
136     r->system = p[4];
137     r->end_head = p[5];
138     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
139     r->end_sector = p[6] & 0x3f;
140     r->start_sector_abs = p[8] | p[9] << 8 | p[10] << 16 | p[11] << 24;
141     r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24;
142 }
143 
144 static int find_partition(BlockDriverState *bs, int partition,
145                           off_t *offset, off_t *size)
146 {
147     struct partition_record mbr[4];
148     uint8_t data[512];
149     int i;
150     int ext_partnum = 4;
151     int ret;
152 
153     if ((ret = bdrv_read(bs, 0, data, 1)) < 0) {
154         errno = -ret;
155         err(EXIT_FAILURE, "error while reading");
156     }
157 
158     if (data[510] != 0x55 || data[511] != 0xaa) {
159         return -EINVAL;
160     }
161 
162     for (i = 0; i < 4; i++) {
163         read_partition(&data[446 + 16 * i], &mbr[i]);
164 
165         if (!mbr[i].nb_sectors_abs)
166             continue;
167 
168         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
169             struct partition_record ext[4];
170             uint8_t data1[512];
171             int j;
172 
173             if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) {
174                 errno = -ret;
175                 err(EXIT_FAILURE, "error while reading");
176             }
177 
178             for (j = 0; j < 4; j++) {
179                 read_partition(&data1[446 + 16 * j], &ext[j]);
180                 if (!ext[j].nb_sectors_abs)
181                     continue;
182 
183                 if ((ext_partnum + j + 1) == partition) {
184                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
185                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
186                     return 0;
187                 }
188             }
189             ext_partnum += 4;
190         } else if ((i + 1) == partition) {
191             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
192             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
193             return 0;
194         }
195     }
196 
197     return -ENOENT;
198 }
199 
200 static void termsig_handler(int signum)
201 {
202     state = TERMINATE;
203     qemu_notify_event();
204 }
205 
206 static void combine_addr(char *buf, size_t len, const char* address,
207                          uint16_t port)
208 {
209     /* If the address-part contains a colon, it's an IPv6 IP so needs [] */
210     if (strstr(address, ":")) {
211         snprintf(buf, len, "[%s]:%u", address, port);
212     } else {
213         snprintf(buf, len, "%s:%u", address, port);
214     }
215 }
216 
217 static int tcp_socket_incoming(const char *address, uint16_t port)
218 {
219     char address_and_port[128];
220     Error *local_err = NULL;
221 
222     combine_addr(address_and_port, 128, address, port);
223     int fd = inet_listen(address_and_port, NULL, 0, SOCK_STREAM, 0, &local_err);
224 
225     if (local_err != NULL) {
226         error_report("%s", error_get_pretty(local_err));
227         error_free(local_err);
228     }
229     return fd;
230 }
231 
232 static int unix_socket_incoming(const char *path)
233 {
234     Error *local_err = NULL;
235     int fd = unix_listen(path, NULL, 0, &local_err);
236 
237     if (local_err != NULL) {
238         error_report("%s", error_get_pretty(local_err));
239         error_free(local_err);
240     }
241     return fd;
242 }
243 
244 static int unix_socket_outgoing(const char *path)
245 {
246     Error *local_err = NULL;
247     int fd = unix_connect(path, &local_err);
248 
249     if (local_err != NULL) {
250         error_report("%s", error_get_pretty(local_err));
251         error_free(local_err);
252     }
253     return fd;
254 }
255 
256 static void *show_parts(void *arg)
257 {
258     char *device = arg;
259     int nbd;
260 
261     /* linux just needs an open() to trigger
262      * the partition table update
263      * but remember to load the module with max_part != 0 :
264      *     modprobe nbd max_part=63
265      */
266     nbd = open(device, O_RDWR);
267     if (nbd >= 0) {
268         close(nbd);
269     }
270     return NULL;
271 }
272 
273 static void *nbd_client_thread(void *arg)
274 {
275     char *device = arg;
276     off_t size;
277     size_t blocksize;
278     uint32_t nbdflags;
279     int fd, sock;
280     int ret;
281     pthread_t show_parts_thread;
282 
283     sock = unix_socket_outgoing(sockpath);
284     if (sock < 0) {
285         goto out;
286     }
287 
288     ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
289                                 &size, &blocksize);
290     if (ret < 0) {
291         goto out_socket;
292     }
293 
294     fd = open(device, O_RDWR);
295     if (fd < 0) {
296         /* Linux-only, we can use %m in printf.  */
297         fprintf(stderr, "Failed to open %s: %m\n", device);
298         goto out_socket;
299     }
300 
301     ret = nbd_init(fd, sock, nbdflags, size, blocksize);
302     if (ret < 0) {
303         goto out_fd;
304     }
305 
306     /* update partition table */
307     pthread_create(&show_parts_thread, NULL, show_parts, device);
308 
309     if (verbose) {
310         fprintf(stderr, "NBD device %s is now connected to %s\n",
311                 device, srcpath);
312     } else {
313         /* Close stderr so that the qemu-nbd process exits.  */
314         dup2(STDOUT_FILENO, STDERR_FILENO);
315     }
316 
317     ret = nbd_client(fd);
318     if (ret) {
319         goto out_fd;
320     }
321     close(fd);
322     kill(getpid(), SIGTERM);
323     return (void *) EXIT_SUCCESS;
324 
325 out_fd:
326     close(fd);
327 out_socket:
328     closesocket(sock);
329 out:
330     kill(getpid(), SIGTERM);
331     return (void *) EXIT_FAILURE;
332 }
333 
334 static int nbd_can_accept(void *opaque)
335 {
336     return nb_fds < shared;
337 }
338 
339 static void nbd_export_closed(NBDExport *exp)
340 {
341     assert(state == TERMINATING);
342     state = TERMINATED;
343 }
344 
345 static void nbd_client_closed(NBDClient *client)
346 {
347     nb_fds--;
348     if (nb_fds == 0 && !persistent && state == RUNNING) {
349         state = TERMINATE;
350     }
351     qemu_notify_event();
352     nbd_client_put(client);
353 }
354 
355 static void nbd_accept(void *opaque)
356 {
357     int server_fd = (uintptr_t) opaque;
358     struct sockaddr_in addr;
359     socklen_t addr_len = sizeof(addr);
360 
361     int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
362     if (fd < 0) {
363         perror("accept");
364         return;
365     }
366 
367     if (state >= TERMINATE) {
368         close(fd);
369         return;
370     }
371 
372     if (nbd_client_new(exp, fd, nbd_client_closed)) {
373         nb_fds++;
374     } else {
375         shutdown(fd, 2);
376         close(fd);
377     }
378 }
379 
380 int main(int argc, char **argv)
381 {
382     BlockDriverState *bs;
383     BlockDriver *drv;
384     off_t dev_offset = 0;
385     uint32_t nbdflags = 0;
386     bool disconnect = false;
387     const char *bindto = "0.0.0.0";
388     char *device = NULL;
389     int port = NBD_DEFAULT_PORT;
390     off_t fd_size;
391     QemuOpts *sn_opts = NULL;
392     const char *sn_id_or_name = NULL;
393     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:";
394     struct option lopt[] = {
395         { "help", 0, NULL, 'h' },
396         { "version", 0, NULL, 'V' },
397         { "bind", 1, NULL, 'b' },
398         { "port", 1, NULL, 'p' },
399         { "socket", 1, NULL, 'k' },
400         { "offset", 1, NULL, 'o' },
401         { "read-only", 0, NULL, 'r' },
402         { "partition", 1, NULL, 'P' },
403         { "connect", 1, NULL, 'c' },
404         { "disconnect", 0, NULL, 'd' },
405         { "snapshot", 0, NULL, 's' },
406         { "load-snapshot", 1, NULL, 'l' },
407         { "nocache", 0, NULL, 'n' },
408         { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
409 #ifdef CONFIG_LINUX_AIO
410         { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
411 #endif
412         { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
413         { "shared", 1, NULL, 'e' },
414         { "format", 1, NULL, 'f' },
415         { "persistent", 0, NULL, 't' },
416         { "verbose", 0, NULL, 'v' },
417         { NULL, 0, NULL, 0 }
418     };
419     int ch;
420     int opt_ind = 0;
421     int li;
422     char *end;
423     int flags = BDRV_O_RDWR;
424     int partition = -1;
425     int ret;
426     int fd;
427     bool seen_cache = false;
428     bool seen_discard = false;
429 #ifdef CONFIG_LINUX_AIO
430     bool seen_aio = false;
431 #endif
432     pthread_t client_thread;
433     const char *fmt = NULL;
434     Error *local_err = NULL;
435 
436     /* The client thread uses SIGTERM to interrupt the server.  A signal
437      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
438      */
439     struct sigaction sa_sigterm;
440     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
441     sa_sigterm.sa_handler = termsig_handler;
442     sigaction(SIGTERM, &sa_sigterm, NULL);
443     qemu_init_exec_dir(argv[0]);
444 
445     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
446         switch (ch) {
447         case 's':
448             flags |= BDRV_O_SNAPSHOT;
449             break;
450         case 'n':
451             optarg = (char *) "none";
452             /* fallthrough */
453         case QEMU_NBD_OPT_CACHE:
454             if (seen_cache) {
455                 errx(EXIT_FAILURE, "-n and --cache can only be specified once");
456             }
457             seen_cache = true;
458             if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
459                 errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg);
460             }
461             break;
462 #ifdef CONFIG_LINUX_AIO
463         case QEMU_NBD_OPT_AIO:
464             if (seen_aio) {
465                 errx(EXIT_FAILURE, "--aio can only be specified once");
466             }
467             seen_aio = true;
468             if (!strcmp(optarg, "native")) {
469                 flags |= BDRV_O_NATIVE_AIO;
470             } else if (!strcmp(optarg, "threads")) {
471                 /* this is the default */
472             } else {
473                errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg);
474             }
475             break;
476 #endif
477         case QEMU_NBD_OPT_DISCARD:
478             if (seen_discard) {
479                 errx(EXIT_FAILURE, "--discard can only be specified once");
480             }
481             seen_discard = true;
482             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
483                 errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg);
484             }
485             break;
486         case 'b':
487             bindto = optarg;
488             break;
489         case 'p':
490             li = strtol(optarg, &end, 0);
491             if (*end) {
492                 errx(EXIT_FAILURE, "Invalid port `%s'", optarg);
493             }
494             if (li < 1 || li > 65535) {
495                 errx(EXIT_FAILURE, "Port out of range `%s'", optarg);
496             }
497             port = (uint16_t)li;
498             break;
499         case 'o':
500                 dev_offset = strtoll (optarg, &end, 0);
501             if (*end) {
502                 errx(EXIT_FAILURE, "Invalid offset `%s'", optarg);
503             }
504             if (dev_offset < 0) {
505                 errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
506             }
507             break;
508         case 'l':
509             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
510                 sn_opts = qemu_opts_parse(&internal_snapshot_opts, optarg, 0);
511                 if (!sn_opts) {
512                     errx(EXIT_FAILURE, "Failed in parsing snapshot param `%s'",
513                          optarg);
514                 }
515             } else {
516                 sn_id_or_name = optarg;
517             }
518             /* fall through */
519         case 'r':
520             nbdflags |= NBD_FLAG_READ_ONLY;
521             flags &= ~BDRV_O_RDWR;
522             break;
523         case 'P':
524             partition = strtol(optarg, &end, 0);
525             if (*end)
526                 errx(EXIT_FAILURE, "Invalid partition `%s'", optarg);
527             if (partition < 1 || partition > 8)
528                 errx(EXIT_FAILURE, "Invalid partition %d", partition);
529             break;
530         case 'k':
531             sockpath = optarg;
532             if (sockpath[0] != '/')
533                 errx(EXIT_FAILURE, "socket path must be absolute\n");
534             break;
535         case 'd':
536             disconnect = true;
537             break;
538         case 'c':
539             device = optarg;
540             break;
541         case 'e':
542             shared = strtol(optarg, &end, 0);
543             if (*end) {
544                 errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg);
545             }
546             if (shared < 1) {
547                 errx(EXIT_FAILURE, "Shared device number must be greater than 0\n");
548             }
549             break;
550         case 'f':
551             fmt = optarg;
552             break;
553 	case 't':
554 	    persistent = 1;
555 	    break;
556         case 'v':
557             verbose = 1;
558             break;
559         case 'V':
560             version(argv[0]);
561             exit(0);
562             break;
563         case 'h':
564             usage(argv[0]);
565             exit(0);
566             break;
567         case '?':
568             errx(EXIT_FAILURE, "Try `%s --help' for more information.",
569                  argv[0]);
570         }
571     }
572 
573     if ((argc - optind) != 1) {
574         errx(EXIT_FAILURE, "Invalid number of argument.\n"
575              "Try `%s --help' for more information.",
576              argv[0]);
577     }
578 
579     if (disconnect) {
580         fd = open(argv[optind], O_RDWR);
581         if (fd < 0) {
582             err(EXIT_FAILURE, "Cannot open %s", argv[optind]);
583         }
584         nbd_disconnect(fd);
585 
586         close(fd);
587 
588         printf("%s disconnected\n", argv[optind]);
589 
590 	return 0;
591     }
592 
593     if (device && !verbose) {
594         int stderr_fd[2];
595         pid_t pid;
596         int ret;
597 
598         if (qemu_pipe(stderr_fd) < 0) {
599             err(EXIT_FAILURE, "Error setting up communication pipe");
600         }
601 
602         /* Now daemonize, but keep a communication channel open to
603          * print errors and exit with the proper status code.
604          */
605         pid = fork();
606         if (pid == 0) {
607             close(stderr_fd[0]);
608             ret = qemu_daemon(1, 0);
609 
610             /* Temporarily redirect stderr to the parent's pipe...  */
611             dup2(stderr_fd[1], STDERR_FILENO);
612             if (ret < 0) {
613                 err(EXIT_FAILURE, "Failed to daemonize");
614             }
615 
616             /* ... close the descriptor we inherited and go on.  */
617             close(stderr_fd[1]);
618         } else {
619             bool errors = false;
620             char *buf;
621 
622             /* In the parent.  Print error messages from the child until
623              * it closes the pipe.
624              */
625             close(stderr_fd[1]);
626             buf = g_malloc(1024);
627             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
628                 errors = true;
629                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
630                 if (ret < 0) {
631                     exit(EXIT_FAILURE);
632                 }
633             }
634             if (ret < 0) {
635                 err(EXIT_FAILURE, "Cannot read from daemon");
636             }
637 
638             /* Usually the daemon should not print any message.
639              * Exit with zero status in that case.
640              */
641             exit(errors);
642         }
643     }
644 
645     if (device != NULL && sockpath == NULL) {
646         sockpath = g_malloc(128);
647         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
648     }
649 
650     qemu_init_main_loop();
651     bdrv_init();
652     atexit(bdrv_close_all);
653 
654     if (fmt) {
655         drv = bdrv_find_format(fmt);
656         if (!drv) {
657             errx(EXIT_FAILURE, "Unknown file format '%s'", fmt);
658         }
659     } else {
660         drv = NULL;
661     }
662 
663     bs = bdrv_new("hda", &error_abort);
664 
665     srcpath = argv[optind];
666     ret = bdrv_open(&bs, srcpath, NULL, NULL, flags, drv, &local_err);
667     if (ret < 0) {
668         errno = -ret;
669         err(EXIT_FAILURE, "Failed to bdrv_open '%s': %s", argv[optind],
670             error_get_pretty(local_err));
671     }
672 
673     if (sn_opts) {
674         ret = bdrv_snapshot_load_tmp(bs,
675                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
676                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
677                                      &local_err);
678     } else if (sn_id_or_name) {
679         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
680                                                    &local_err);
681     }
682     if (ret < 0) {
683         errno = -ret;
684         err(EXIT_FAILURE,
685             "Failed to load snapshot: %s",
686             error_get_pretty(local_err));
687     }
688 
689     fd_size = bdrv_getlength(bs);
690 
691     if (partition != -1) {
692         ret = find_partition(bs, partition, &dev_offset, &fd_size);
693         if (ret < 0) {
694             errno = -ret;
695             err(EXIT_FAILURE, "Could not find partition %d", partition);
696         }
697     }
698 
699     exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed);
700 
701     if (sockpath) {
702         fd = unix_socket_incoming(sockpath);
703     } else {
704         fd = tcp_socket_incoming(bindto, port);
705     }
706 
707     if (fd < 0) {
708         return 1;
709     }
710 
711     if (device) {
712         int ret;
713 
714         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
715         if (ret != 0) {
716             errx(EXIT_FAILURE, "Failed to create client thread: %s",
717                  strerror(ret));
718         }
719     } else {
720         /* Shut up GCC warnings.  */
721         memset(&client_thread, 0, sizeof(client_thread));
722     }
723 
724     qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
725                          (void *)(uintptr_t)fd);
726 
727     /* now when the initialization is (almost) complete, chdir("/")
728      * to free any busy filesystems */
729     if (chdir("/") < 0) {
730         err(EXIT_FAILURE, "Could not chdir to root directory");
731     }
732 
733     state = RUNNING;
734     do {
735         main_loop_wait(false);
736         if (state == TERMINATE) {
737             state = TERMINATING;
738             nbd_export_close(exp);
739             nbd_export_put(exp);
740             exp = NULL;
741         }
742     } while (state != TERMINATED);
743 
744     bdrv_close(bs);
745     if (sockpath) {
746         unlink(sockpath);
747     }
748 
749     if (sn_opts) {
750         qemu_opts_del(sn_opts);
751     }
752 
753     if (device) {
754         void *ret;
755         pthread_join(client_thread, &ret);
756         exit(ret != NULL);
757     } else {
758         exit(EXIT_SUCCESS);
759     }
760 }
761