xref: /openbmc/qemu/qemu-nbd.c (revision 0bdb12c7)
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/osdep.h"
20 #include "qapi/error.h"
21 #include "qemu-common.h"
22 #include "qemu/cutils.h"
23 #include "sysemu/block-backend.h"
24 #include "block/block_int.h"
25 #include "block/nbd.h"
26 #include "qemu/main-loop.h"
27 #include "qemu/error-report.h"
28 #include "qemu/config-file.h"
29 #include "qemu/bswap.h"
30 #include "qemu/log.h"
31 #include "block/snapshot.h"
32 #include "qapi/util.h"
33 #include "qapi/qmp/qstring.h"
34 #include "qom/object_interfaces.h"
35 #include "io/channel-socket.h"
36 #include "crypto/init.h"
37 #include "trace/control.h"
38 
39 #include <getopt.h>
40 #include <libgen.h>
41 #include <pthread.h>
42 
43 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
44 #define QEMU_NBD_OPT_CACHE         256
45 #define QEMU_NBD_OPT_AIO           257
46 #define QEMU_NBD_OPT_DISCARD       258
47 #define QEMU_NBD_OPT_DETECT_ZEROES 259
48 #define QEMU_NBD_OPT_OBJECT        260
49 #define QEMU_NBD_OPT_TLSCREDS      261
50 #define QEMU_NBD_OPT_IMAGE_OPTS    262
51 
52 #define MBR_SIZE 512
53 
54 static NBDExport *exp;
55 static bool newproto;
56 static int verbose;
57 static char *srcpath;
58 static SocketAddress *saddr;
59 static int persistent = 0;
60 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
61 static int shared = 1;
62 static int nb_fds;
63 static QIOChannelSocket *server_ioc;
64 static int server_watch = -1;
65 static QCryptoTLSCreds *tlscreds;
66 
67 static void usage(const char *name)
68 {
69     (printf) (
70 "Usage: %s [OPTIONS] FILE\n"
71 "QEMU Disk Network Block Device Server\n"
72 "\n"
73 "  -h, --help                display this help and exit\n"
74 "  -V, --version             output version information and exit\n"
75 "\n"
76 "Connection properties:\n"
77 "  -p, --port=PORT           port to listen on (default `%d')\n"
78 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
79 "  -k, --socket=PATH         path to the unix socket\n"
80 "                            (default '"SOCKET_PATH"')\n"
81 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
82 "  -t, --persistent          don't exit on the last connection\n"
83 "  -v, --verbose             display extra debugging information\n"
84 "  -x, --export-name=NAME    expose export by name\n"
85 "\n"
86 "Exposing part of the image:\n"
87 "  -o, --offset=OFFSET       offset into the image\n"
88 "  -P, --partition=NUM       only expose partition NUM\n"
89 "\n"
90 "General purpose options:\n"
91 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
92 "                            passwords and/or encryption keys\n"
93 "  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
94 "                            specify tracing options\n"
95 #ifdef __linux__
96 "Kernel NBD client support:\n"
97 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
98 "  -d, --disconnect          disconnect the specified device\n"
99 "\n"
100 #endif
101 "\n"
102 "Block device options:\n"
103 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
104 "  -r, --read-only           export read-only\n"
105 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
106 "                            file with backing_file=FILE, redirect the write to\n"
107 "                            the temporary one\n"
108 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
109 "                            load an internal snapshot inside FILE and export it\n"
110 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
111 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
112 "                            '[ID_OR_NAME]'\n"
113 "  -n, --nocache             disable host cache\n"
114 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
115 "      --aio=MODE            set AIO mode (native or threads)\n"
116 "      --discard=MODE        set discard mode (ignore, unmap)\n"
117 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
118 "      --image-opts          treat FILE as a full set of image options\n"
119 "\n"
120 "Report bugs to <qemu-devel@nongnu.org>\n"
121     , name, NBD_DEFAULT_PORT, "DEVICE");
122 }
123 
124 static void version(const char *name)
125 {
126     printf(
127 "%s version 0.0.1\n"
128 "Written by Anthony Liguori.\n"
129 "\n"
130 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
131 "This is free software; see the source for copying conditions.  There is NO\n"
132 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
133     , name);
134 }
135 
136 struct partition_record
137 {
138     uint8_t bootable;
139     uint8_t start_head;
140     uint32_t start_cylinder;
141     uint8_t start_sector;
142     uint8_t system;
143     uint8_t end_head;
144     uint8_t end_cylinder;
145     uint8_t end_sector;
146     uint32_t start_sector_abs;
147     uint32_t nb_sectors_abs;
148 };
149 
150 static void read_partition(uint8_t *p, struct partition_record *r)
151 {
152     r->bootable = p[0];
153     r->start_head = p[1];
154     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
155     r->start_sector = p[2] & 0x3f;
156     r->system = p[4];
157     r->end_head = p[5];
158     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
159     r->end_sector = p[6] & 0x3f;
160 
161     r->start_sector_abs = ldl_le_p(p + 8);
162     r->nb_sectors_abs   = ldl_le_p(p + 12);
163 }
164 
165 static int find_partition(BlockBackend *blk, int partition,
166                           off_t *offset, off_t *size)
167 {
168     struct partition_record mbr[4];
169     uint8_t data[MBR_SIZE];
170     int i;
171     int ext_partnum = 4;
172     int ret;
173 
174     ret = blk_pread(blk, 0, data, sizeof(data));
175     if (ret < 0) {
176         error_report("error while reading: %s", strerror(-ret));
177         exit(EXIT_FAILURE);
178     }
179 
180     if (data[510] != 0x55 || data[511] != 0xaa) {
181         return -EINVAL;
182     }
183 
184     for (i = 0; i < 4; i++) {
185         read_partition(&data[446 + 16 * i], &mbr[i]);
186 
187         if (!mbr[i].system || !mbr[i].nb_sectors_abs) {
188             continue;
189         }
190 
191         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
192             struct partition_record ext[4];
193             uint8_t data1[MBR_SIZE];
194             int j;
195 
196             ret = blk_pread(blk, mbr[i].start_sector_abs * MBR_SIZE,
197                             data1, sizeof(data1));
198             if (ret < 0) {
199                 error_report("error while reading: %s", strerror(-ret));
200                 exit(EXIT_FAILURE);
201             }
202 
203             for (j = 0; j < 4; j++) {
204                 read_partition(&data1[446 + 16 * j], &ext[j]);
205                 if (!ext[j].system || !ext[j].nb_sectors_abs) {
206                     continue;
207                 }
208 
209                 if ((ext_partnum + j + 1) == partition) {
210                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
211                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
212                     return 0;
213                 }
214             }
215             ext_partnum += 4;
216         } else if ((i + 1) == partition) {
217             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
218             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
219             return 0;
220         }
221     }
222 
223     return -ENOENT;
224 }
225 
226 static void termsig_handler(int signum)
227 {
228     atomic_cmpxchg(&state, RUNNING, TERMINATE);
229     qemu_notify_event();
230 }
231 
232 
233 static void *show_parts(void *arg)
234 {
235     char *device = arg;
236     int nbd;
237 
238     /* linux just needs an open() to trigger
239      * the partition table update
240      * but remember to load the module with max_part != 0 :
241      *     modprobe nbd max_part=63
242      */
243     nbd = open(device, O_RDWR);
244     if (nbd >= 0) {
245         close(nbd);
246     }
247     return NULL;
248 }
249 
250 static void *nbd_client_thread(void *arg)
251 {
252     char *device = arg;
253     off_t size;
254     uint16_t nbdflags;
255     QIOChannelSocket *sioc;
256     int fd;
257     int ret;
258     pthread_t show_parts_thread;
259     Error *local_error = NULL;
260 
261     sioc = qio_channel_socket_new();
262     if (qio_channel_socket_connect_sync(sioc,
263                                         saddr,
264                                         &local_error) < 0) {
265         error_report_err(local_error);
266         goto out;
267     }
268 
269     ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), NULL, &nbdflags,
270                                 NULL, NULL, NULL,
271                                 &size, &local_error);
272     if (ret < 0) {
273         if (local_error) {
274             error_report_err(local_error);
275         }
276         goto out_socket;
277     }
278 
279     fd = open(device, O_RDWR);
280     if (fd < 0) {
281         /* Linux-only, we can use %m in printf.  */
282         error_report("Failed to open %s: %m", device);
283         goto out_socket;
284     }
285 
286     ret = nbd_init(fd, sioc, nbdflags, size);
287     if (ret < 0) {
288         goto out_fd;
289     }
290 
291     /* update partition table */
292     pthread_create(&show_parts_thread, NULL, show_parts, device);
293 
294     if (verbose) {
295         fprintf(stderr, "NBD device %s is now connected to %s\n",
296                 device, srcpath);
297     } else {
298         /* Close stderr so that the qemu-nbd process exits.  */
299         dup2(STDOUT_FILENO, STDERR_FILENO);
300     }
301 
302     ret = nbd_client(fd);
303     if (ret) {
304         goto out_fd;
305     }
306     close(fd);
307     object_unref(OBJECT(sioc));
308     kill(getpid(), SIGTERM);
309     return (void *) EXIT_SUCCESS;
310 
311 out_fd:
312     close(fd);
313 out_socket:
314     object_unref(OBJECT(sioc));
315 out:
316     kill(getpid(), SIGTERM);
317     return (void *) EXIT_FAILURE;
318 }
319 
320 static int nbd_can_accept(void)
321 {
322     return nb_fds < shared;
323 }
324 
325 static void nbd_export_closed(NBDExport *exp)
326 {
327     assert(state == TERMINATING);
328     state = TERMINATED;
329 }
330 
331 static void nbd_update_server_watch(void);
332 
333 static void nbd_client_closed(NBDClient *client)
334 {
335     nb_fds--;
336     if (nb_fds == 0 && !persistent && state == RUNNING) {
337         state = TERMINATE;
338     }
339     nbd_update_server_watch();
340     nbd_client_put(client);
341 }
342 
343 static gboolean nbd_accept(QIOChannel *ioc, GIOCondition cond, gpointer opaque)
344 {
345     QIOChannelSocket *cioc;
346 
347     cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
348                                      NULL);
349     if (!cioc) {
350         return TRUE;
351     }
352 
353     if (state >= TERMINATE) {
354         object_unref(OBJECT(cioc));
355         return TRUE;
356     }
357 
358     nb_fds++;
359     nbd_update_server_watch();
360     nbd_client_new(newproto ? NULL : exp, cioc,
361                    tlscreds, NULL, nbd_client_closed);
362     object_unref(OBJECT(cioc));
363 
364     return TRUE;
365 }
366 
367 static void nbd_update_server_watch(void)
368 {
369     if (nbd_can_accept()) {
370         if (server_watch == -1) {
371             server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc),
372                                                  G_IO_IN,
373                                                  nbd_accept,
374                                                  NULL, NULL);
375         }
376     } else {
377         if (server_watch != -1) {
378             g_source_remove(server_watch);
379             server_watch = -1;
380         }
381     }
382 }
383 
384 
385 static SocketAddress *nbd_build_socket_address(const char *sockpath,
386                                                const char *bindto,
387                                                const char *port)
388 {
389     SocketAddress *saddr;
390 
391     saddr = g_new0(SocketAddress, 1);
392     if (sockpath) {
393         saddr->type = SOCKET_ADDRESS_KIND_UNIX;
394         saddr->u.q_unix.data = g_new0(UnixSocketAddress, 1);
395         saddr->u.q_unix.data->path = g_strdup(sockpath);
396     } else {
397         InetSocketAddress *inet;
398         saddr->type = SOCKET_ADDRESS_KIND_INET;
399         inet = saddr->u.inet.data = g_new0(InetSocketAddress, 1);
400         inet->host = g_strdup(bindto);
401         if (port) {
402             inet->port = g_strdup(port);
403         } else  {
404             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
405         }
406     }
407 
408     return saddr;
409 }
410 
411 
412 static QemuOptsList file_opts = {
413     .name = "file",
414     .implied_opt_name = "file",
415     .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
416     .desc = {
417         /* no elements => accept any params */
418         { /* end of list */ }
419     },
420 };
421 
422 static QemuOptsList qemu_object_opts = {
423     .name = "object",
424     .implied_opt_name = "qom-type",
425     .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
426     .desc = {
427         { }
428     },
429 };
430 
431 
432 
433 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
434 {
435     Object *obj;
436     QCryptoTLSCreds *creds;
437 
438     obj = object_resolve_path_component(
439         object_get_objects_root(), id);
440     if (!obj) {
441         error_setg(errp, "No TLS credentials with id '%s'",
442                    id);
443         return NULL;
444     }
445     creds = (QCryptoTLSCreds *)
446         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
447     if (!creds) {
448         error_setg(errp, "Object with id '%s' is not TLS credentials",
449                    id);
450         return NULL;
451     }
452 
453     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
454         error_setg(errp,
455                    "Expecting TLS credentials with a server endpoint");
456         return NULL;
457     }
458     object_ref(obj);
459     return creds;
460 }
461 
462 
463 int main(int argc, char **argv)
464 {
465     BlockBackend *blk;
466     BlockDriverState *bs;
467     off_t dev_offset = 0;
468     uint16_t nbdflags = 0;
469     bool disconnect = false;
470     const char *bindto = "0.0.0.0";
471     const char *port = NULL;
472     char *sockpath = NULL;
473     char *device = NULL;
474     off_t fd_size;
475     QemuOpts *sn_opts = NULL;
476     const char *sn_id_or_name = NULL;
477     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:";
478     struct option lopt[] = {
479         { "help", no_argument, NULL, 'h' },
480         { "version", no_argument, NULL, 'V' },
481         { "bind", required_argument, NULL, 'b' },
482         { "port", required_argument, NULL, 'p' },
483         { "socket", required_argument, NULL, 'k' },
484         { "offset", required_argument, NULL, 'o' },
485         { "read-only", no_argument, NULL, 'r' },
486         { "partition", required_argument, NULL, 'P' },
487         { "connect", required_argument, NULL, 'c' },
488         { "disconnect", no_argument, NULL, 'd' },
489         { "snapshot", no_argument, NULL, 's' },
490         { "load-snapshot", required_argument, NULL, 'l' },
491         { "nocache", no_argument, NULL, 'n' },
492         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
493         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
494         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
495         { "detect-zeroes", required_argument, NULL,
496           QEMU_NBD_OPT_DETECT_ZEROES },
497         { "shared", required_argument, NULL, 'e' },
498         { "format", required_argument, NULL, 'f' },
499         { "persistent", no_argument, NULL, 't' },
500         { "verbose", no_argument, NULL, 'v' },
501         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
502         { "export-name", required_argument, NULL, 'x' },
503         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
504         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
505         { "trace", required_argument, NULL, 'T' },
506         { NULL, 0, NULL, 0 }
507     };
508     int ch;
509     int opt_ind = 0;
510     char *end;
511     int flags = BDRV_O_RDWR;
512     int partition = -1;
513     int ret = 0;
514     bool seen_cache = false;
515     bool seen_discard = false;
516     bool seen_aio = false;
517     pthread_t client_thread;
518     const char *fmt = NULL;
519     Error *local_err = NULL;
520     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
521     QDict *options = NULL;
522     const char *export_name = NULL;
523     const char *tlscredsid = NULL;
524     bool imageOpts = false;
525     bool writethrough = true;
526     char *trace_file = NULL;
527 
528     /* The client thread uses SIGTERM to interrupt the server.  A signal
529      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
530      */
531     struct sigaction sa_sigterm;
532     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
533     sa_sigterm.sa_handler = termsig_handler;
534     sigaction(SIGTERM, &sa_sigterm, NULL);
535 
536     qcrypto_init(&error_fatal);
537 
538     module_call_init(MODULE_INIT_QOM);
539     qemu_add_opts(&qemu_object_opts);
540     qemu_add_opts(&qemu_trace_opts);
541     qemu_init_exec_dir(argv[0]);
542 
543     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
544         switch (ch) {
545         case 's':
546             flags |= BDRV_O_SNAPSHOT;
547             break;
548         case 'n':
549             optarg = (char *) "none";
550             /* fallthrough */
551         case QEMU_NBD_OPT_CACHE:
552             if (seen_cache) {
553                 error_report("-n and --cache can only be specified once");
554                 exit(EXIT_FAILURE);
555             }
556             seen_cache = true;
557             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
558                 error_report("Invalid cache mode `%s'", optarg);
559                 exit(EXIT_FAILURE);
560             }
561             break;
562         case QEMU_NBD_OPT_AIO:
563             if (seen_aio) {
564                 error_report("--aio can only be specified once");
565                 exit(EXIT_FAILURE);
566             }
567             seen_aio = true;
568             if (!strcmp(optarg, "native")) {
569                 flags |= BDRV_O_NATIVE_AIO;
570             } else if (!strcmp(optarg, "threads")) {
571                 /* this is the default */
572             } else {
573                error_report("invalid aio mode `%s'", optarg);
574                exit(EXIT_FAILURE);
575             }
576             break;
577         case QEMU_NBD_OPT_DISCARD:
578             if (seen_discard) {
579                 error_report("--discard can only be specified once");
580                 exit(EXIT_FAILURE);
581             }
582             seen_discard = true;
583             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
584                 error_report("Invalid discard mode `%s'", optarg);
585                 exit(EXIT_FAILURE);
586             }
587             break;
588         case QEMU_NBD_OPT_DETECT_ZEROES:
589             detect_zeroes =
590                 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
591                                 optarg,
592                                 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX,
593                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
594                                 &local_err);
595             if (local_err) {
596                 error_reportf_err(local_err,
597                                   "Failed to parse detect_zeroes mode: ");
598                 exit(EXIT_FAILURE);
599             }
600             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
601                 !(flags & BDRV_O_UNMAP)) {
602                 error_report("setting detect-zeroes to unmap is not allowed "
603                              "without setting discard operation to unmap");
604                 exit(EXIT_FAILURE);
605             }
606             break;
607         case 'b':
608             bindto = optarg;
609             break;
610         case 'p':
611             port = optarg;
612             break;
613         case 'o':
614                 dev_offset = strtoll (optarg, &end, 0);
615             if (*end) {
616                 error_report("Invalid offset `%s'", optarg);
617                 exit(EXIT_FAILURE);
618             }
619             if (dev_offset < 0) {
620                 error_report("Offset must be positive `%s'", optarg);
621                 exit(EXIT_FAILURE);
622             }
623             break;
624         case 'l':
625             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
626                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
627                                                   optarg, false);
628                 if (!sn_opts) {
629                     error_report("Failed in parsing snapshot param `%s'",
630                                  optarg);
631                     exit(EXIT_FAILURE);
632                 }
633             } else {
634                 sn_id_or_name = optarg;
635             }
636             /* fall through */
637         case 'r':
638             nbdflags |= NBD_FLAG_READ_ONLY;
639             flags &= ~BDRV_O_RDWR;
640             break;
641         case 'P':
642             partition = strtol(optarg, &end, 0);
643             if (*end) {
644                 error_report("Invalid partition `%s'", optarg);
645                 exit(EXIT_FAILURE);
646             }
647             if (partition < 1 || partition > 8) {
648                 error_report("Invalid partition %d", partition);
649                 exit(EXIT_FAILURE);
650             }
651             break;
652         case 'k':
653             sockpath = optarg;
654             if (sockpath[0] != '/') {
655                 error_report("socket path must be absolute");
656                 exit(EXIT_FAILURE);
657             }
658             break;
659         case 'd':
660             disconnect = true;
661             break;
662         case 'c':
663             device = optarg;
664             break;
665         case 'e':
666             shared = strtol(optarg, &end, 0);
667             if (*end) {
668                 error_report("Invalid shared device number '%s'", optarg);
669                 exit(EXIT_FAILURE);
670             }
671             if (shared < 1) {
672                 error_report("Shared device number must be greater than 0");
673                 exit(EXIT_FAILURE);
674             }
675             break;
676         case 'f':
677             fmt = optarg;
678             break;
679         case 't':
680             persistent = 1;
681             break;
682         case 'x':
683             export_name = optarg;
684             break;
685         case 'v':
686             verbose = 1;
687             break;
688         case 'V':
689             version(argv[0]);
690             exit(0);
691             break;
692         case 'h':
693             usage(argv[0]);
694             exit(0);
695             break;
696         case '?':
697             error_report("Try `%s --help' for more information.", argv[0]);
698             exit(EXIT_FAILURE);
699         case QEMU_NBD_OPT_OBJECT: {
700             QemuOpts *opts;
701             opts = qemu_opts_parse_noisily(&qemu_object_opts,
702                                            optarg, true);
703             if (!opts) {
704                 exit(EXIT_FAILURE);
705             }
706         }   break;
707         case QEMU_NBD_OPT_TLSCREDS:
708             tlscredsid = optarg;
709             break;
710         case QEMU_NBD_OPT_IMAGE_OPTS:
711             imageOpts = true;
712             break;
713         case 'T':
714             g_free(trace_file);
715             trace_file = trace_opt_parse(optarg);
716             break;
717         }
718     }
719 
720     if ((argc - optind) != 1) {
721         error_report("Invalid number of arguments");
722         error_printf("Try `%s --help' for more information.\n", argv[0]);
723         exit(EXIT_FAILURE);
724     }
725 
726     if (qemu_opts_foreach(&qemu_object_opts,
727                           user_creatable_add_opts_foreach,
728                           NULL, NULL)) {
729         exit(EXIT_FAILURE);
730     }
731 
732     if (!trace_init_backends()) {
733         exit(1);
734     }
735     trace_init_file(trace_file);
736     qemu_set_log(LOG_TRACE);
737 
738     if (tlscredsid) {
739         if (sockpath) {
740             error_report("TLS is only supported with IPv4/IPv6");
741             exit(EXIT_FAILURE);
742         }
743         if (device) {
744             error_report("TLS is not supported with a host device");
745             exit(EXIT_FAILURE);
746         }
747         if (!export_name) {
748             /* Set the default NBD protocol export name, since
749              * we *must* use new style protocol for TLS */
750             export_name = "";
751         }
752         tlscreds = nbd_get_tls_creds(tlscredsid, &local_err);
753         if (local_err) {
754             error_report("Failed to get TLS creds %s",
755                          error_get_pretty(local_err));
756             exit(EXIT_FAILURE);
757         }
758     }
759 
760     if (disconnect) {
761         int nbdfd = open(argv[optind], O_RDWR);
762         if (nbdfd < 0) {
763             error_report("Cannot open %s: %s", argv[optind],
764                          strerror(errno));
765             exit(EXIT_FAILURE);
766         }
767         nbd_disconnect(nbdfd);
768 
769         close(nbdfd);
770 
771         printf("%s disconnected\n", argv[optind]);
772 
773         return 0;
774     }
775 
776     if (device && !verbose) {
777         int stderr_fd[2];
778         pid_t pid;
779         int ret;
780 
781         if (qemu_pipe(stderr_fd) < 0) {
782             error_report("Error setting up communication pipe: %s",
783                          strerror(errno));
784             exit(EXIT_FAILURE);
785         }
786 
787         /* Now daemonize, but keep a communication channel open to
788          * print errors and exit with the proper status code.
789          */
790         pid = fork();
791         if (pid < 0) {
792             error_report("Failed to fork: %s", strerror(errno));
793             exit(EXIT_FAILURE);
794         } else if (pid == 0) {
795             close(stderr_fd[0]);
796             ret = qemu_daemon(1, 0);
797 
798             /* Temporarily redirect stderr to the parent's pipe...  */
799             dup2(stderr_fd[1], STDERR_FILENO);
800             if (ret < 0) {
801                 error_report("Failed to daemonize: %s", strerror(errno));
802                 exit(EXIT_FAILURE);
803             }
804 
805             /* ... close the descriptor we inherited and go on.  */
806             close(stderr_fd[1]);
807         } else {
808             bool errors = false;
809             char *buf;
810 
811             /* In the parent.  Print error messages from the child until
812              * it closes the pipe.
813              */
814             close(stderr_fd[1]);
815             buf = g_malloc(1024);
816             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
817                 errors = true;
818                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
819                 if (ret < 0) {
820                     exit(EXIT_FAILURE);
821                 }
822             }
823             if (ret < 0) {
824                 error_report("Cannot read from daemon: %s",
825                              strerror(errno));
826                 exit(EXIT_FAILURE);
827             }
828 
829             /* Usually the daemon should not print any message.
830              * Exit with zero status in that case.
831              */
832             exit(errors);
833         }
834     }
835 
836     if (device != NULL && sockpath == NULL) {
837         sockpath = g_malloc(128);
838         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
839     }
840 
841     saddr = nbd_build_socket_address(sockpath, bindto, port);
842 
843     if (qemu_init_main_loop(&local_err)) {
844         error_report_err(local_err);
845         exit(EXIT_FAILURE);
846     }
847     bdrv_init();
848     atexit(bdrv_close_all);
849 
850     srcpath = argv[optind];
851     if (imageOpts) {
852         QemuOpts *opts;
853         if (fmt) {
854             error_report("--image-opts and -f are mutually exclusive");
855             exit(EXIT_FAILURE);
856         }
857         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
858         if (!opts) {
859             qemu_opts_reset(&file_opts);
860             exit(EXIT_FAILURE);
861         }
862         options = qemu_opts_to_qdict(opts, NULL);
863         qemu_opts_reset(&file_opts);
864         blk = blk_new_open(NULL, NULL, options, flags, &local_err);
865     } else {
866         if (fmt) {
867             options = qdict_new();
868             qdict_put(options, "driver", qstring_from_str(fmt));
869         }
870         blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
871     }
872 
873     if (!blk) {
874         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
875                           argv[optind]);
876         exit(EXIT_FAILURE);
877     }
878     bs = blk_bs(blk);
879 
880     blk_set_enable_write_cache(blk, !writethrough);
881 
882     if (sn_opts) {
883         ret = bdrv_snapshot_load_tmp(bs,
884                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
885                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
886                                      &local_err);
887     } else if (sn_id_or_name) {
888         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
889                                                    &local_err);
890     }
891     if (ret < 0) {
892         error_reportf_err(local_err, "Failed to load snapshot: ");
893         exit(EXIT_FAILURE);
894     }
895 
896     bs->detect_zeroes = detect_zeroes;
897     fd_size = blk_getlength(blk);
898     if (fd_size < 0) {
899         error_report("Failed to determine the image length: %s",
900                      strerror(-fd_size));
901         exit(EXIT_FAILURE);
902     }
903 
904     if (partition != -1) {
905         ret = find_partition(blk, partition, &dev_offset, &fd_size);
906         if (ret < 0) {
907             error_report("Could not find partition %d: %s", partition,
908                          strerror(-ret));
909             exit(EXIT_FAILURE);
910         }
911     }
912 
913     exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed,
914                          writethrough, NULL, &local_err);
915     if (!exp) {
916         error_report_err(local_err);
917         exit(EXIT_FAILURE);
918     }
919     if (export_name) {
920         nbd_export_set_name(exp, export_name);
921         newproto = true;
922     }
923 
924     server_ioc = qio_channel_socket_new();
925     if (qio_channel_socket_listen_sync(server_ioc, saddr, &local_err) < 0) {
926         object_unref(OBJECT(server_ioc));
927         error_report_err(local_err);
928         return 1;
929     }
930 
931     if (device) {
932         int ret;
933 
934         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
935         if (ret != 0) {
936             error_report("Failed to create client thread: %s", strerror(ret));
937             exit(EXIT_FAILURE);
938         }
939     } else {
940         /* Shut up GCC warnings.  */
941         memset(&client_thread, 0, sizeof(client_thread));
942     }
943 
944     nbd_update_server_watch();
945 
946     /* now when the initialization is (almost) complete, chdir("/")
947      * to free any busy filesystems */
948     if (chdir("/") < 0) {
949         error_report("Could not chdir to root directory: %s",
950                      strerror(errno));
951         exit(EXIT_FAILURE);
952     }
953 
954     state = RUNNING;
955     do {
956         main_loop_wait(false);
957         if (state == TERMINATE) {
958             state = TERMINATING;
959             nbd_export_close(exp);
960             nbd_export_put(exp);
961             exp = NULL;
962         }
963     } while (state != TERMINATED);
964 
965     blk_unref(blk);
966     if (sockpath) {
967         unlink(sockpath);
968     }
969 
970     qemu_opts_del(sn_opts);
971 
972     if (device) {
973         void *ret;
974         pthread_join(client_thread, &ret);
975         exit(ret != NULL);
976     } else {
977         exit(EXIT_SUCCESS);
978     }
979 }
980