aboutsummaryrefslogtreecommitdiff
path: root/qemu-nbd.c
blob: bf9c5fedceba45d36e275334f368e4d28efa72f8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
/*
 *  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/osdep.h"
#include <getopt.h>
#include <libgen.h>
#include <pthread.h>

#include "qemu-common.h"
#include "qapi/error.h"
#include "qemu/cutils.h"
#include "sysemu/block-backend.h"
#include "sysemu/runstate.h" /* for qemu_system_killed() prototype */
#include "block/block_int.h"
#include "block/nbd.h"
#include "qemu/main-loop.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include "qemu/error-report.h"
#include "qemu/config-file.h"
#include "qemu/bswap.h"
#include "qemu/log.h"
#include "qemu/systemd.h"
#include "block/snapshot.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qstring.h"
#include "qom/object_interfaces.h"
#include "io/channel-socket.h"
#include "io/net-listener.h"
#include "crypto/init.h"
#include "crypto/tlscreds.h"
#include "trace/control.h"
#include "qemu-version.h"

#ifdef CONFIG_SELINUX
#include <selinux/selinux.h>
#endif

#ifdef __linux__
#define HAVE_NBD_DEVICE 1
#else
#define HAVE_NBD_DEVICE 0
#endif

#define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
#define QEMU_NBD_OPT_CACHE         256
#define QEMU_NBD_OPT_AIO           257
#define QEMU_NBD_OPT_DISCARD       258
#define QEMU_NBD_OPT_DETECT_ZEROES 259
#define QEMU_NBD_OPT_OBJECT        260
#define QEMU_NBD_OPT_TLSCREDS      261
#define QEMU_NBD_OPT_IMAGE_OPTS    262
#define QEMU_NBD_OPT_FORK          263
#define QEMU_NBD_OPT_TLSAUTHZ      264
#define QEMU_NBD_OPT_PID_FILE      265
#define QEMU_NBD_OPT_SELINUX_LABEL 266
#define QEMU_NBD_OPT_TLSHOSTNAME   267

#define MBR_SIZE 512

static int verbose;
static char *srcpath;
static SocketAddress *saddr;
static int persistent = 0;
static enum { RUNNING, TERMINATE, TERMINATED } state;
static int shared = 1;
static int nb_fds;
static QIONetListener *server;
static QCryptoTLSCreds *tlscreds;
static const char *tlsauthz;

static void usage(const char *name)
{
    (printf) (
"Usage: %s [OPTIONS] FILE\n"
"  or:  %s -L [OPTIONS]\n"
"QEMU Disk Network Block Device Utility\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"
"  -x, --export-name=NAME    expose export by name (default is empty string)\n"
"  -D, --description=TEXT    export a human-readable description\n"
"\n"
"Exposing part of the image:\n"
"  -o, --offset=OFFSET       offset into the image\n"
"  -A, --allocation-depth    expose the allocation depth\n"
"  -B, --bitmap=NAME         expose a persistent dirty bitmap\n"
"\n"
"General purpose options:\n"
"  -L, --list                list exports available from another NBD server\n"
"  --object type,id=ID,...   define an object such as 'secret' for providing\n"
"                            passwords and/or encryption keys\n"
"  --tls-creds=ID            use id of an earlier --object to provide TLS\n"
"  --tls-authz=ID            use id of an earlier --object to provide\n"
"                            authorization\n"
"  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
"                            specify tracing options\n"
"  --fork                    fork off the server process and exit the parent\n"
"                            once the server is running\n"
"  --pid-file=PATH           store the server's process ID in the given file\n"
#ifdef CONFIG_SELINUX
"  --selinux-label=LABEL     set SELinux process label on listening socket\n"
#endif
#if HAVE_NBD_DEVICE
"\n"
"Kernel NBD client support:\n"
"  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
"  -d, --disconnect          disconnect the specified device\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 used to access the disk image, the\n"
"                            valid options are: 'none', 'writeback' (default),\n"
"                            'writethrough', 'directsync' and 'unsafe'\n"
"      --aio=MODE            set AIO mode (native, io_uring or threads)\n"
"      --discard=MODE        set discard mode (ignore, unmap)\n"
"      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
"      --image-opts          treat FILE as a full set of image options\n"
"\n"
QEMU_HELP_BOTTOM "\n"
    , name, name, NBD_DEFAULT_PORT, "DEVICE");
}

static void version(const char *name)
{
    printf(
"%s " QEMU_FULL_VERSION "\n"
"Written by Anthony Liguori.\n"
"\n"
QEMU_COPYRIGHT "\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);
}

#ifdef CONFIG_POSIX
/*
 * The client thread uses SIGTERM to interrupt the server.  A signal
 * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 */
void qemu_system_killed(int signum, pid_t pid)
{
    qatomic_cmpxchg(&state, RUNNING, TERMINATE);
    qemu_notify_event();
}
#endif /* CONFIG_POSIX */

static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
                                const char *hostname)
{
    int ret = EXIT_FAILURE;
    int rc;
    Error *err = NULL;
    QIOChannelSocket *sioc;
    NBDExportInfo *list;
    int i, j;

    sioc = qio_channel_socket_new();
    if (qio_channel_socket_connect_sync(sioc, saddr, &err) < 0) {
        error_report_err(err);
        goto out;
    }
    rc = nbd_receive_export_list(QIO_CHANNEL(sioc), tls, hostname, &list,
                                 &err);
    if (rc < 0) {
        if (err) {
            error_report_err(err);
        }
        goto out;
    }
    printf("exports available: %d\n", rc);
    for (i = 0; i < rc; i++) {
        printf(" export: '%s'\n", list[i].name);
        if (list[i].description && *list[i].description) {
            printf("  description: %s\n", list[i].description);
        }
        if (list[i].flags & NBD_FLAG_HAS_FLAGS) {
            static const char *const flag_names[] = {
                [NBD_FLAG_READ_ONLY_BIT]            = "readonly",
                [NBD_FLAG_SEND_FLUSH_BIT]           = "flush",
                [NBD_FLAG_SEND_FUA_BIT]             = "fua",
                [NBD_FLAG_ROTATIONAL_BIT]           = "rotational",
                [NBD_FLAG_SEND_TRIM_BIT]            = "trim",
                [NBD_FLAG_SEND_WRITE_ZEROES_BIT]    = "zeroes",
                [NBD_FLAG_SEND_DF_BIT]              = "df",
                [NBD_FLAG_CAN_MULTI_CONN_BIT]       = "multi",
                [NBD_FLAG_SEND_RESIZE_BIT]          = "resize",
                [NBD_FLAG_SEND_CACHE_BIT]           = "cache",
                [NBD_FLAG_SEND_FAST_ZERO_BIT]       = "fast-zero",
            };

            printf("  size:  %" PRIu64 "\n", list[i].size);
            printf("  flags: 0x%x (", list[i].flags);
            for (size_t bit = 0; bit < ARRAY_SIZE(flag_names); bit++) {
                if (flag_names[bit] && (list[i].flags & (1 << bit))) {
                    printf(" %s", flag_names[bit]);
                }
            }
            printf(" )\n");
        }
        if (list[i].min_block) {
            printf("  min block: %u\n", list[i].min_block);
            printf("  opt block: %u\n", list[i].opt_block);
            printf("  max block: %u\n", list[i].max_block);
        }
        if (list[i].n_contexts) {
            printf("  available meta contexts: %d\n", list[i].n_contexts);
            for (j = 0; j < list[i].n_contexts; j++) {
                printf("   %s\n", list[i].contexts[j]);
            }
        }
    }
    nbd_free_export_list(list, rc);

    ret = EXIT_SUCCESS;
 out:
    object_unref(OBJECT(sioc));
    return ret;
}


#if HAVE_NBD_DEVICE
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;
    NBDExportInfo info = { .request_sizes = false, .name = g_strdup("") };
    QIOChannelSocket *sioc;
    int fd = -1;
    int ret = EXIT_FAILURE;
    pthread_t show_parts_thread;
    Error *local_error = NULL;

    sioc = qio_channel_socket_new();
    if (qio_channel_socket_connect_sync(sioc,
                                        saddr,
                                        &local_error) < 0) {
        error_report_err(local_error);
        goto out;
    }

    if (nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc),
                              NULL, NULL, NULL, &info, &local_error) < 0) {
        if (local_error) {
            error_report_err(local_error);
        }
        goto out;
    }

    fd = open(device, O_RDWR);
    if (fd < 0) {
        /* Linux-only, we can use %m in printf.  */
        error_report("Failed to open %s: %m", device);
        goto out;
    }

    if (nbd_init(fd, sioc, &info, &local_error) < 0) {
        error_report_err(local_error);
        goto out;
    }

    /* 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);
    }

    if (nbd_client(fd) < 0) {
        goto out;
    }

    ret = EXIT_SUCCESS;

 out:
    if (fd >= 0) {
        close(fd);
    }
    object_unref(OBJECT(sioc));
    g_free(info.name);
    kill(getpid(), SIGTERM);
    return (void *) (intptr_t) ret;
}
#endif /* HAVE_NBD_DEVICE */

static int nbd_can_accept(void)
{
    return state == RUNNING && (shared == 0 || nb_fds < shared);
}

static void nbd_update_server_watch(void);

static void nbd_client_closed(NBDClient *client, bool negotiated)
{
    nb_fds--;
    if (negotiated && nb_fds == 0 && !persistent && state == RUNNING) {
        state = TERMINATE;
    }
    nbd_update_server_watch();
    nbd_client_put(client);
}

static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
                       gpointer opaque)
{
    if (state >= TERMINATE) {
        return;
    }

    nb_fds++;
    nbd_update_server_watch();
    nbd_client_new(cioc, tlscreds, tlsauthz, nbd_client_closed);
}

static void nbd_update_server_watch(void)
{
    if (nbd_can_accept()) {
        qio_net_listener_set_client_func(server, nbd_accept, NULL, NULL);
    } else {
        qio_net_listener_set_client_func(server, 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->type = SOCKET_ADDRESS_TYPE_UNIX;
        saddr->u.q_unix.path = g_strdup(sockpath);
    } else {
        InetSocketAddress *inet;
        saddr->type = SOCKET_ADDRESS_TYPE_INET;
        inet = &saddr->u.inet;
        inet->host = g_strdup(bindto);
        if (port) {
            inet->port = g_strdup(port);
        } else  {
            inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
        }
    }

    return saddr;
}


static QemuOptsList file_opts = {
    .name = "file",
    .implied_opt_name = "file",
    .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
    .desc = {
        /* no elements => accept any params */
        { /* end of list */ }
    },
};

static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, bool list,
                                          Error **errp)
{
    Object *obj;
    QCryptoTLSCreds *creds;

    obj = object_resolve_path_component(
        object_get_objects_root(), id);
    if (!obj) {
        error_setg(errp, "No TLS credentials with id '%s'",
                   id);
        return NULL;
    }
    creds = (QCryptoTLSCreds *)
        object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
    if (!creds) {
        error_setg(errp, "Object with id '%s' is not TLS credentials",
                   id);
        return NULL;
    }

    if (!qcrypto_tls_creds_check_endpoint(creds,
                                          list
                                          ? QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT
                                          : QCRYPTO_TLS_CREDS_ENDPOINT_SERVER,
                                          errp)) {
        return NULL;
    }
    object_ref(obj);
    return creds;
}

static void setup_address_and_port(const char **address, const char **port)
{
    if (*address == NULL) {
        *address = "0.0.0.0";
    }

    if (*port == NULL) {
        *port = stringify(NBD_DEFAULT_PORT);
    }
}

/*
 * Check socket parameters compatibility when socket activation is used.
 */
static const char *socket_activation_validate_opts(const char *device,
                                                   const char *sockpath,
                                                   const char *address,
                                                   const char *port,
                                                   const char *selinux,
                                                   bool list)
{
    if (device != NULL) {
        return "NBD device can't be set when using socket activation";
    }

    if (sockpath != NULL) {
        return "Unix socket can't be set when using socket activation";
    }

    if (address != NULL) {
        return "The interface can't be set when using socket activation";
    }

    if (port != NULL) {
        return "TCP port number can't be set when using socket activation";
    }

    if (selinux != NULL) {
        return "SELinux label can't be set when using socket activation";
    }

    if (list) {
        return "List mode is incompatible with socket activation";
    }

    return NULL;
}

static void qemu_nbd_shutdown(void)
{
    job_cancel_sync_all();
    blk_exp_close_all();
    bdrv_close_all();
}

int main(int argc, char **argv)
{
    BlockBackend *blk;
    BlockDriverState *bs;
    uint64_t dev_offset = 0;
    bool readonly = false;
    bool disconnect = false;
    const char *bindto = NULL;
    const char *port = NULL;
    char *sockpath = NULL;
    char *device = NULL;
    QemuOpts *sn_opts = NULL;
    const char *sn_id_or_name = NULL;
    const char *sopt = "hVb:o:p:rsnc:dvk:e:f:tl:x:T:D:AB:L";
    struct option lopt[] = {
        { "help", no_argument, NULL, 'h' },
        { "version", no_argument, NULL, 'V' },
        { "bind", required_argument, NULL, 'b' },
        { "port", required_argument, NULL, 'p' },
        { "socket", required_argument, NULL, 'k' },
        { "offset", required_argument, NULL, 'o' },
        { "read-only", no_argument, NULL, 'r' },
        { "allocation-depth", no_argument, NULL, 'A' },
        { "bitmap", required_argument, NULL, 'B' },
        { "connect", required_argument, NULL, 'c' },
        { "disconnect", no_argument, NULL, 'd' },
        { "list", no_argument, NULL, 'L' },
        { "snapshot", no_argument, NULL, 's' },
        { "load-snapshot", required_argument, NULL, 'l' },
        { "nocache", no_argument, NULL, 'n' },
        { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
        { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
        { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
        { "detect-zeroes", required_argument, NULL,
          QEMU_NBD_OPT_DETECT_ZEROES },
        { "shared", required_argument, NULL, 'e' },
        { "format", required_argument, NULL, 'f' },
        { "persistent", no_argument, NULL, 't' },
        { "verbose", no_argument, NULL, 'v' },
        { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
        { "export-name", required_argument, NULL, 'x' },
        { "description", required_argument, NULL, 'D' },
        { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
        { "tls-hostname", required_argument, NULL, QEMU_NBD_OPT_TLSHOSTNAME },
        { "tls-authz", required_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
        { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
        { "trace", required_argument, NULL, 'T' },
        { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
        { "pid-file", required_argument, NULL, QEMU_NBD_OPT_PID_FILE },
        { "selinux-label", required_argument, NULL,
          QEMU_NBD_OPT_SELINUX_LABEL },
        { NULL, 0, NULL, 0 }
    };
    int ch;
    int opt_ind = 0;
    int flags = BDRV_O_RDWR;
    int ret = 0;
    bool seen_cache = false;
    bool seen_discard = false;
    bool seen_aio = false;
    pthread_t client_thread;
    const char *fmt = NULL;
    Error *local_err = NULL;
    BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
    QDict *options = NULL;
    const char *export_name = NULL; /* defaults to "" later for server mode */
    const char *export_description = NULL;
    strList *bitmaps = NULL;
    bool alloc_depth = false;
    const char *tlscredsid = NULL;
    const char *tlshostname = NULL;
    bool imageOpts = false;
    bool writethrough = false; /* Client will flush as needed. */
    bool fork_process = false;
    bool list = false;
    int old_stderr = -1;
    unsigned socket_activation;
    const char *pid_file_name = NULL;
    const char *selinux_label = NULL;
    BlockExportOptions *export_opts;

#ifdef CONFIG_POSIX
    os_setup_early_signal_handling();
    os_setup_signal_handling();
#endif

    socket_init();
    error_init(argv[0]);
    module_call_init(MODULE_INIT_TRACE);
    qcrypto_init(&error_fatal);

    module_call_init(MODULE_INIT_QOM);
    qemu_add_opts(&qemu_trace_opts);
    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) {
                error_report("-n and --cache can only be specified once");
                exit(EXIT_FAILURE);
            }
            seen_cache = true;
            if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
                error_report("Invalid cache mode `%s'", optarg);
                exit(EXIT_FAILURE);
            }
            break;
        case QEMU_NBD_OPT_AIO:
            if (seen_aio) {
                error_report("--aio can only be specified once");
                exit(EXIT_FAILURE);
            }
            seen_aio = true;
            if (bdrv_parse_aio(optarg, &flags) < 0) {
                error_report("Invalid aio mode '%s'", optarg);
                exit(EXIT_FAILURE);
            }
            break;
        case QEMU_NBD_OPT_DISCARD:
            if (seen_discard) {
                error_report("--discard can only be specified once");
                exit(EXIT_FAILURE);
            }
            seen_discard = true;
            if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
                error_report("Invalid discard mode `%s'", optarg);
                exit(EXIT_FAILURE);
            }
            break;
        case QEMU_NBD_OPT_DETECT_ZEROES:
            detect_zeroes =
                qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup,
                                optarg,
                                BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
                                &local_err);
            if (local_err) {
                error_reportf_err(local_err,
                                  "Failed to parse detect_zeroes mode: ");
                exit(EXIT_FAILURE);
            }
            if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
                !(flags & BDRV_O_UNMAP)) {
                error_report("setting detect-zeroes to unmap is not allowed "
                             "without setting discard operation to unmap");
                exit(EXIT_FAILURE);
            }
            break;
        case 'b':
            bindto = optarg;
            break;
        case 'p':
            port = optarg;
            break;
        case 'o':
            if (qemu_strtou64(optarg, NULL, 0, &dev_offset) < 0) {
                error_report("Invalid offset '%s'", optarg);
                exit(EXIT_FAILURE);
            }
            break;
        case 'l':
            if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
                sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
                                                  optarg, false);
                if (!sn_opts) {
                    error_report("Failed in parsing snapshot param `%s'",
                                 optarg);
                    exit(EXIT_FAILURE);
                }
            } else {
                sn_id_or_name = optarg;
            }
            /* fall through */
        case 'r':
            readonly = true;
            flags &= ~BDRV_O_RDWR;
            break;
        case 'A':
            alloc_depth = true;
            break;
        case 'B':
            QAPI_LIST_PREPEND(bitmaps, g_strdup(optarg));
            break;
        case 'k':
            sockpath = optarg;
            if (sockpath[0] != '/') {
                error_report("socket path must be absolute");
                exit(EXIT_FAILURE);
            }
            break;
        case 'd':
            disconnect = true;
            break;
        case 'c':
            device = optarg;
            break;
        case 'e':
            if (qemu_strtoi(optarg, NULL, 0, &shared) < 0 ||
                shared < 0) {
                error_report("Invalid shared device number '%s'", optarg);
                exit(EXIT_FAILURE);
            }
            break;
        case 'f':
            fmt = optarg;
            break;
        case 't':
            persistent = 1;
            break;
        case 'x':
            export_name = optarg;
            if (strlen(export_name) > NBD_MAX_STRING_SIZE) {
                error_report("export name '%s' too long", export_name);
                exit(EXIT_FAILURE);
            }
            break;
        case 'D':
            export_description = optarg;
            if (strlen(export_description) > NBD_MAX_STRING_SIZE) {
                error_report("export description '%s' too long",
                             export_description);
                exit(EXIT_FAILURE);
            }
            break;
        case 'v':
            verbose = 1;
            break;
        case 'V':
            version(argv[0]);
            exit(0);
            break;
        case 'h':
            usage(argv[0]);
            exit(0);
            break;
        case '?':
            error_report("Try `%s --help' for more information.", argv[0]);
            exit(EXIT_FAILURE);
        case QEMU_NBD_OPT_OBJECT:
            user_creatable_process_cmdline(optarg);
            break;
        case QEMU_NBD_OPT_TLSCREDS:
            tlscredsid = optarg;
            break;
        case QEMU_NBD_OPT_TLSHOSTNAME:
            tlshostname = optarg;
            break;
        case QEMU_NBD_OPT_IMAGE_OPTS:
            imageOpts = true;
            break;
        case 'T':
            trace_opt_parse(optarg);
            break;
        case QEMU_NBD_OPT_TLSAUTHZ:
            tlsauthz = optarg;
            break;
        case QEMU_NBD_OPT_FORK:
            fork_process = true;
            break;
        case 'L':
            list = true;
            break;
        case QEMU_NBD_OPT_PID_FILE:
            pid_file_name = optarg;
            break;
        case QEMU_NBD_OPT_SELINUX_LABEL:
            selinux_label = optarg;
            break;
        }
    }

    if (list) {
        if (argc != optind) {
            error_report("List mode is incompatible with a file name");
            exit(EXIT_FAILURE);
        }
        if (export_name || export_description || dev_offset ||
            device || disconnect || fmt || sn_id_or_name || bitmaps ||
            alloc_depth || seen_aio || seen_discard || seen_cache) {
            error_report("List mode is incompatible with per-device settings");
            exit(EXIT_FAILURE);
        }
        if (fork_process) {
            error_report("List mode is incompatible with forking");
            exit(EXIT_FAILURE);
        }
    } else if ((argc - optind) != 1) {
        error_report("Invalid number of arguments");
        error_printf("Try `%s --help' for more information.\n", argv[0]);
        exit(EXIT_FAILURE);
    } else if (!export_name) {
        export_name = "";
    }

    if (!trace_init_backends()) {
        exit(1);
    }
    trace_init_file();
    qemu_set_log(LOG_TRACE, &error_fatal);

    socket_activation = check_socket_activation();
    if (socket_activation == 0) {
        if (!sockpath) {
            setup_address_and_port(&bindto, &port);
        }
    } else {
        /* Using socket activation - check user didn't use -p etc. */
        const char *err_msg = socket_activation_validate_opts(device, sockpath,
                                                              bindto, port,
                                                              selinux_label,
                                                              list);
        if (err_msg != NULL) {
            error_report("%s", err_msg);
            exit(EXIT_FAILURE);
        }

        /* qemu-nbd can only listen on a single socket.  */
        if (socket_activation > 1) {
            error_report("qemu-nbd does not support socket activation with %s > 1",
                         "LISTEN_FDS");
            exit(EXIT_FAILURE);
        }
    }

    if (tlscredsid) {
        if (device) {
            error_report("TLS is not supported with a host device");
            exit(EXIT_FAILURE);
        }
        if (tlsauthz && list) {
            error_report("TLS authorization is incompatible with export list");
            exit(EXIT_FAILURE);
        }
        if (tlshostname && !list) {
            error_report("TLS hostname is only supported with export list");
            exit(EXIT_FAILURE);
        }
        tlscreds = nbd_get_tls_creds(tlscredsid, list, &local_err);
        if (local_err) {
            error_reportf_err(local_err, "Failed to get TLS creds: ");
            exit(EXIT_FAILURE);
        }
    } else {
        if (tlsauthz) {
            error_report("--tls-authz is not permitted without --tls-creds");
            exit(EXIT_FAILURE);
        }
        if (tlshostname) {
            error_report("--tls-hostname is not permitted without --tls-creds");
            exit(EXIT_FAILURE);
        }
    }

    if (selinux_label) {
#ifdef CONFIG_SELINUX
        if (sockpath == NULL && device == NULL) {
            error_report("--selinux-label is not permitted without --socket");
            exit(EXIT_FAILURE);
        }
#else
        error_report("SELinux support not enabled in this binary");
        exit(EXIT_FAILURE);
#endif
    }

    if (list) {
        saddr = nbd_build_socket_address(sockpath, bindto, port);
        return qemu_nbd_client_list(saddr, tlscreds,
                                    tlshostname ? tlshostname : bindto);
    }

#if !HAVE_NBD_DEVICE
    if (disconnect || device) {
        error_report("Kernel /dev/nbdN support not available");
        exit(EXIT_FAILURE);
    }
#else /* HAVE_NBD_DEVICE */
    if (disconnect) {
        int nbdfd = open(argv[optind], O_RDWR);
        if (nbdfd < 0) {
            error_report("Cannot open %s: %s", argv[optind],
                         strerror(errno));
            exit(EXIT_FAILURE);
        }
        nbd_disconnect(nbdfd);

        close(nbdfd);

        printf("%s disconnected\n", argv[optind]);

        return 0;
    }
#endif

    if ((device && !verbose) || fork_process) {
#ifndef WIN32
        int stderr_fd[2];
        pid_t pid;
        int ret;

        if (qemu_pipe(stderr_fd) < 0) {
            error_report("Error setting up communication pipe: %s",
                         strerror(errno));
            exit(EXIT_FAILURE);
        }

        /* Now daemonize, but keep a communication channel open to
         * print errors and exit with the proper status code.
         */
        pid = fork();
        if (pid < 0) {
            error_report("Failed to fork: %s", strerror(errno));
            exit(EXIT_FAILURE);
        } else if (pid == 0) {
            close(stderr_fd[0]);

            /* Remember parent's stderr if we will be restoring it. */
            if (fork_process) {
                old_stderr = dup(STDERR_FILENO);
            }

            ret = qemu_daemon(1, 0);

            /* Temporarily redirect stderr to the parent's pipe...  */
            dup2(stderr_fd[1], STDERR_FILENO);
            if (ret < 0) {
                error_report("Failed to daemonize: %s", strerror(errno));
                exit(EXIT_FAILURE);
            }

            /* ... 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) {
                error_report("Cannot read from daemon: %s",
                             strerror(errno));
                exit(EXIT_FAILURE);
            }

            /* Usually the daemon should not print any message.
             * Exit with zero status in that case.
             */
            exit(errors);
        }
#else /* WIN32 */
        error_report("Unable to fork into background on Windows hosts");
        exit(EXIT_FAILURE);
#endif /* WIN32 */
    }

    if (device != NULL && sockpath == NULL) {
        sockpath = g_malloc(128);
        snprintf(sockpath, 128, SOCKET_PATH, basename(device));
    }

    server = qio_net_listener_new();
    if (socket_activation == 0) {
        int backlog;

        if (persistent || shared == 0) {
            backlog = SOMAXCONN;
        } else {
            backlog = MIN(shared, SOMAXCONN);
        }
#ifdef CONFIG_SELINUX
        if (selinux_label && setsockcreatecon_raw(selinux_label) == -1) {
            error_report("Cannot set SELinux socket create context to %s: %s",
                         selinux_label, strerror(errno));
            exit(EXIT_FAILURE);
        }
#endif
        saddr = nbd_build_socket_address(sockpath, bindto, port);
        if (qio_net_listener_open_sync(server, saddr, backlog,
                                       &local_err) < 0) {
            object_unref(OBJECT(server));
            error_report_err(local_err);
            exit(EXIT_FAILURE);
        }
#ifdef CONFIG_SELINUX
        if (selinux_label && setsockcreatecon_raw(NULL) == -1) {
            error_report("Cannot clear SELinux socket create context: %s",
                         strerror(errno));
            exit(EXIT_FAILURE);
        }
#endif
    } else {
        size_t i;
        /* See comment in check_socket_activation above. */
        for (i = 0; i < socket_activation; i++) {
            QIOChannelSocket *sioc;
            sioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD + i,
                                             &local_err);
            if (sioc == NULL) {
                object_unref(OBJECT(server));
                error_reportf_err(local_err,
                                  "Failed to use socket activation: ");
                exit(EXIT_FAILURE);
            }
            qio_net_listener_add(server, sioc);
            object_unref(OBJECT(sioc));
        }
    }

    qemu_init_main_loop(&error_fatal);
    bdrv_init();
    atexit(qemu_nbd_shutdown);

    srcpath = argv[optind];
    if (imageOpts) {
        QemuOpts *opts;
        if (fmt) {
            error_report("--image-opts and -f are mutually exclusive");
            exit(EXIT_FAILURE);
        }
        opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
        if (!opts) {
            qemu_opts_reset(&file_opts);
            exit(EXIT_FAILURE);
        }
        options = qemu_opts_to_qdict(opts, NULL);
        qemu_opts_reset(&file_opts);
        blk = blk_new_open(NULL, NULL, options, flags, &local_err);
    } else {
        if (fmt) {
            options = qdict_new();
            qdict_put_str(options, "driver", fmt);
        }
        blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
    }

    if (!blk) {
        error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
                          argv[optind]);
        exit(EXIT_FAILURE);
    }
    bs = blk_bs(blk);

    if (dev_offset) {
        QDict *raw_opts = qdict_new();
        qdict_put_str(raw_opts, "driver", "raw");
        qdict_put_str(raw_opts, "file", bs->node_name);
        qdict_put_int(raw_opts, "offset", dev_offset);
        bs = bdrv_open(NULL, NULL, raw_opts, flags, &error_fatal);
        blk_remove_bs(blk);
        blk_insert_bs(blk, bs, &error_fatal);
        bdrv_unref(bs);
    }

    blk_set_enable_write_cache(blk, !writethrough);

    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) {
        error_reportf_err(local_err, "Failed to load snapshot: ");
        exit(EXIT_FAILURE);
    }

    bs->detect_zeroes = detect_zeroes;

    nbd_server_is_qemu_nbd(true);

    export_opts = g_new(BlockExportOptions, 1);
    *export_opts = (BlockExportOptions) {
        .type               = BLOCK_EXPORT_TYPE_NBD,
        .id                 = g_strdup("qemu-nbd-export"),
        .node_name          = g_strdup(bdrv_get_node_name(bs)),
        .has_writethrough   = true,
        .writethrough       = writethrough,
        .has_writable       = true,
        .writable           = !readonly,
        .u.nbd = {
            .has_name             = true,
            .name                 = g_strdup(export_name),
            .has_description      = !!export_description,
            .description          = g_strdup(export_description),
            .has_bitmaps          = !!bitmaps,
            .bitmaps              = bitmaps,
            .has_allocation_depth = alloc_depth,
            .allocation_depth     = alloc_depth,
        },
    };
    blk_exp_add(export_opts, &error_fatal);
    qapi_free_BlockExportOptions(export_opts);

    if (device) {
#if HAVE_NBD_DEVICE
        int ret;

        ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
        if (ret != 0) {
            error_report("Failed to create client thread: %s", strerror(ret));
            exit(EXIT_FAILURE);
        }
#endif
    } else {
        /* Shut up GCC warnings.  */
        memset(&client_thread, 0, sizeof(client_thread));
    }

    nbd_update_server_watch();

    if (pid_file_name) {
        qemu_write_pidfile(pid_file_name, &error_fatal);
    }

    /* now when the initialization is (almost) complete, chdir("/")
     * to free any busy filesystems */
    if (chdir("/") < 0) {
        error_report("Could not chdir to root directory: %s",
                     strerror(errno));
        exit(EXIT_FAILURE);
    }

    if (fork_process) {
        dup2(old_stderr, STDERR_FILENO);
        close(old_stderr);
    }

    state = RUNNING;
    do {
        main_loop_wait(false);
        if (state == TERMINATE) {
            blk_exp_close_all();
            state = TERMINATED;
        }
    } 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);
    }
}