xref: /openbmc/qemu/qemu-nbd.c (revision acb0ef58)
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         close(fd);
376     }
377 }
378 
379 int main(int argc, char **argv)
380 {
381     BlockDriverState *bs;
382     BlockDriver *drv;
383     off_t dev_offset = 0;
384     uint32_t nbdflags = 0;
385     bool disconnect = false;
386     const char *bindto = "0.0.0.0";
387     char *device = NULL;
388     int port = NBD_DEFAULT_PORT;
389     off_t fd_size;
390     QemuOpts *sn_opts = NULL;
391     const char *sn_id_or_name = NULL;
392     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:";
393     struct option lopt[] = {
394         { "help", 0, NULL, 'h' },
395         { "version", 0, NULL, 'V' },
396         { "bind", 1, NULL, 'b' },
397         { "port", 1, NULL, 'p' },
398         { "socket", 1, NULL, 'k' },
399         { "offset", 1, NULL, 'o' },
400         { "read-only", 0, NULL, 'r' },
401         { "partition", 1, NULL, 'P' },
402         { "connect", 1, NULL, 'c' },
403         { "disconnect", 0, NULL, 'd' },
404         { "snapshot", 0, NULL, 's' },
405         { "load-snapshot", 1, NULL, 'l' },
406         { "nocache", 0, NULL, 'n' },
407         { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
408 #ifdef CONFIG_LINUX_AIO
409         { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
410 #endif
411         { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
412         { "shared", 1, NULL, 'e' },
413         { "format", 1, NULL, 'f' },
414         { "persistent", 0, NULL, 't' },
415         { "verbose", 0, NULL, 'v' },
416         { NULL, 0, NULL, 0 }
417     };
418     int ch;
419     int opt_ind = 0;
420     int li;
421     char *end;
422     int flags = BDRV_O_RDWR;
423     int partition = -1;
424     int ret;
425     int fd;
426     bool seen_cache = false;
427     bool seen_discard = false;
428 #ifdef CONFIG_LINUX_AIO
429     bool seen_aio = false;
430 #endif
431     pthread_t client_thread;
432     const char *fmt = NULL;
433     Error *local_err = NULL;
434 
435     /* The client thread uses SIGTERM to interrupt the server.  A signal
436      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
437      */
438     struct sigaction sa_sigterm;
439     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
440     sa_sigterm.sa_handler = termsig_handler;
441     sigaction(SIGTERM, &sa_sigterm, NULL);
442     qemu_init_exec_dir(argv[0]);
443 
444     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
445         switch (ch) {
446         case 's':
447             flags |= BDRV_O_SNAPSHOT;
448             break;
449         case 'n':
450             optarg = (char *) "none";
451             /* fallthrough */
452         case QEMU_NBD_OPT_CACHE:
453             if (seen_cache) {
454                 errx(EXIT_FAILURE, "-n and --cache can only be specified once");
455             }
456             seen_cache = true;
457             if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
458                 errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg);
459             }
460             break;
461 #ifdef CONFIG_LINUX_AIO
462         case QEMU_NBD_OPT_AIO:
463             if (seen_aio) {
464                 errx(EXIT_FAILURE, "--aio can only be specified once");
465             }
466             seen_aio = true;
467             if (!strcmp(optarg, "native")) {
468                 flags |= BDRV_O_NATIVE_AIO;
469             } else if (!strcmp(optarg, "threads")) {
470                 /* this is the default */
471             } else {
472                errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg);
473             }
474             break;
475 #endif
476         case QEMU_NBD_OPT_DISCARD:
477             if (seen_discard) {
478                 errx(EXIT_FAILURE, "--discard can only be specified once");
479             }
480             seen_discard = true;
481             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
482                 errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg);
483             }
484             break;
485         case 'b':
486             bindto = optarg;
487             break;
488         case 'p':
489             li = strtol(optarg, &end, 0);
490             if (*end) {
491                 errx(EXIT_FAILURE, "Invalid port `%s'", optarg);
492             }
493             if (li < 1 || li > 65535) {
494                 errx(EXIT_FAILURE, "Port out of range `%s'", optarg);
495             }
496             port = (uint16_t)li;
497             break;
498         case 'o':
499                 dev_offset = strtoll (optarg, &end, 0);
500             if (*end) {
501                 errx(EXIT_FAILURE, "Invalid offset `%s'", optarg);
502             }
503             if (dev_offset < 0) {
504                 errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
505             }
506             break;
507         case 'l':
508             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
509                 sn_opts = qemu_opts_parse(&internal_snapshot_opts, optarg, 0);
510                 if (!sn_opts) {
511                     errx(EXIT_FAILURE, "Failed in parsing snapshot param `%s'",
512                          optarg);
513                 }
514             } else {
515                 sn_id_or_name = optarg;
516             }
517             /* fall through */
518         case 'r':
519             nbdflags |= NBD_FLAG_READ_ONLY;
520             flags &= ~BDRV_O_RDWR;
521             break;
522         case 'P':
523             partition = strtol(optarg, &end, 0);
524             if (*end)
525                 errx(EXIT_FAILURE, "Invalid partition `%s'", optarg);
526             if (partition < 1 || partition > 8)
527                 errx(EXIT_FAILURE, "Invalid partition %d", partition);
528             break;
529         case 'k':
530             sockpath = optarg;
531             if (sockpath[0] != '/')
532                 errx(EXIT_FAILURE, "socket path must be absolute\n");
533             break;
534         case 'd':
535             disconnect = true;
536             break;
537         case 'c':
538             device = optarg;
539             break;
540         case 'e':
541             shared = strtol(optarg, &end, 0);
542             if (*end) {
543                 errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg);
544             }
545             if (shared < 1) {
546                 errx(EXIT_FAILURE, "Shared device number must be greater than 0\n");
547             }
548             break;
549         case 'f':
550             fmt = optarg;
551             break;
552 	case 't':
553 	    persistent = 1;
554 	    break;
555         case 'v':
556             verbose = 1;
557             break;
558         case 'V':
559             version(argv[0]);
560             exit(0);
561             break;
562         case 'h':
563             usage(argv[0]);
564             exit(0);
565             break;
566         case '?':
567             errx(EXIT_FAILURE, "Try `%s --help' for more information.",
568                  argv[0]);
569         }
570     }
571 
572     if ((argc - optind) != 1) {
573         errx(EXIT_FAILURE, "Invalid number of argument.\n"
574              "Try `%s --help' for more information.",
575              argv[0]);
576     }
577 
578     if (disconnect) {
579         fd = open(argv[optind], O_RDWR);
580         if (fd < 0) {
581             err(EXIT_FAILURE, "Cannot open %s", argv[optind]);
582         }
583         nbd_disconnect(fd);
584 
585         close(fd);
586 
587         printf("%s disconnected\n", argv[optind]);
588 
589 	return 0;
590     }
591 
592     if (device && !verbose) {
593         int stderr_fd[2];
594         pid_t pid;
595         int ret;
596 
597         if (qemu_pipe(stderr_fd) < 0) {
598             err(EXIT_FAILURE, "Error setting up communication pipe");
599         }
600 
601         /* Now daemonize, but keep a communication channel open to
602          * print errors and exit with the proper status code.
603          */
604         pid = fork();
605         if (pid == 0) {
606             close(stderr_fd[0]);
607             ret = qemu_daemon(1, 0);
608 
609             /* Temporarily redirect stderr to the parent's pipe...  */
610             dup2(stderr_fd[1], STDERR_FILENO);
611             if (ret < 0) {
612                 err(EXIT_FAILURE, "Failed to daemonize");
613             }
614 
615             /* ... close the descriptor we inherited and go on.  */
616             close(stderr_fd[1]);
617         } else {
618             bool errors = false;
619             char *buf;
620 
621             /* In the parent.  Print error messages from the child until
622              * it closes the pipe.
623              */
624             close(stderr_fd[1]);
625             buf = g_malloc(1024);
626             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
627                 errors = true;
628                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
629                 if (ret < 0) {
630                     exit(EXIT_FAILURE);
631                 }
632             }
633             if (ret < 0) {
634                 err(EXIT_FAILURE, "Cannot read from daemon");
635             }
636 
637             /* Usually the daemon should not print any message.
638              * Exit with zero status in that case.
639              */
640             exit(errors);
641         }
642     }
643 
644     if (device != NULL && sockpath == NULL) {
645         sockpath = g_malloc(128);
646         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
647     }
648 
649     qemu_init_main_loop();
650     bdrv_init();
651     atexit(bdrv_close_all);
652 
653     if (fmt) {
654         drv = bdrv_find_format(fmt);
655         if (!drv) {
656             errx(EXIT_FAILURE, "Unknown file format '%s'", fmt);
657         }
658     } else {
659         drv = NULL;
660     }
661 
662     bs = bdrv_new("hda", &error_abort);
663 
664     srcpath = argv[optind];
665     ret = bdrv_open(&bs, srcpath, NULL, NULL, flags, drv, &local_err);
666     if (ret < 0) {
667         errno = -ret;
668         err(EXIT_FAILURE, "Failed to bdrv_open '%s': %s", argv[optind],
669             error_get_pretty(local_err));
670     }
671 
672     if (sn_opts) {
673         ret = bdrv_snapshot_load_tmp(bs,
674                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
675                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
676                                      &local_err);
677     } else if (sn_id_or_name) {
678         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
679                                                    &local_err);
680     }
681     if (ret < 0) {
682         errno = -ret;
683         err(EXIT_FAILURE,
684             "Failed to load snapshot: %s",
685             error_get_pretty(local_err));
686     }
687 
688     fd_size = bdrv_getlength(bs);
689 
690     if (partition != -1) {
691         ret = find_partition(bs, partition, &dev_offset, &fd_size);
692         if (ret < 0) {
693             errno = -ret;
694             err(EXIT_FAILURE, "Could not find partition %d", partition);
695         }
696     }
697 
698     exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed);
699 
700     if (sockpath) {
701         fd = unix_socket_incoming(sockpath);
702     } else {
703         fd = tcp_socket_incoming(bindto, port);
704     }
705 
706     if (fd < 0) {
707         return 1;
708     }
709 
710     if (device) {
711         int ret;
712 
713         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
714         if (ret != 0) {
715             errx(EXIT_FAILURE, "Failed to create client thread: %s",
716                  strerror(ret));
717         }
718     } else {
719         /* Shut up GCC warnings.  */
720         memset(&client_thread, 0, sizeof(client_thread));
721     }
722 
723     qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
724                          (void *)(uintptr_t)fd);
725 
726     /* now when the initialization is (almost) complete, chdir("/")
727      * to free any busy filesystems */
728     if (chdir("/") < 0) {
729         err(EXIT_FAILURE, "Could not chdir to root directory");
730     }
731 
732     state = RUNNING;
733     do {
734         main_loop_wait(false);
735         if (state == TERMINATE) {
736             state = TERMINATING;
737             nbd_export_close(exp);
738             nbd_export_put(exp);
739             exp = NULL;
740         }
741     } while (state != TERMINATED);
742 
743     bdrv_close(bs);
744     if (sockpath) {
745         unlink(sockpath);
746     }
747 
748     if (sn_opts) {
749         qemu_opts_del(sn_opts);
750     }
751 
752     if (device) {
753         void *ret;
754         pthread_join(client_thread, &ret);
755         exit(ret != NULL);
756     } else {
757         exit(EXIT_SUCCESS);
758     }
759 }
760