xref: /openbmc/qemu/qemu-nbd.c (revision 88cd34ee)
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 <getopt.h>
21 #include <libgen.h>
22 #include <pthread.h>
23 
24 #include "qemu-common.h"
25 #include "qapi/error.h"
26 #include "qemu/cutils.h"
27 #include "sysemu/block-backend.h"
28 #include "block/block_int.h"
29 #include "block/nbd.h"
30 #include "qemu/main-loop.h"
31 #include "qemu/module.h"
32 #include "qemu/option.h"
33 #include "qemu/error-report.h"
34 #include "qemu/config-file.h"
35 #include "qemu/bswap.h"
36 #include "qemu/log.h"
37 #include "qemu/systemd.h"
38 #include "block/snapshot.h"
39 #include "qapi/qmp/qdict.h"
40 #include "qapi/qmp/qstring.h"
41 #include "qom/object_interfaces.h"
42 #include "io/channel-socket.h"
43 #include "io/net-listener.h"
44 #include "crypto/init.h"
45 #include "trace/control.h"
46 #include "qemu-version.h"
47 
48 #ifdef __linux__
49 #define HAVE_NBD_DEVICE 1
50 #else
51 #define HAVE_NBD_DEVICE 0
52 #endif
53 
54 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
55 #define QEMU_NBD_OPT_CACHE         256
56 #define QEMU_NBD_OPT_AIO           257
57 #define QEMU_NBD_OPT_DISCARD       258
58 #define QEMU_NBD_OPT_DETECT_ZEROES 259
59 #define QEMU_NBD_OPT_OBJECT        260
60 #define QEMU_NBD_OPT_TLSCREDS      261
61 #define QEMU_NBD_OPT_IMAGE_OPTS    262
62 #define QEMU_NBD_OPT_FORK          263
63 #define QEMU_NBD_OPT_TLSAUTHZ      264
64 #define QEMU_NBD_OPT_PID_FILE      265
65 
66 #define MBR_SIZE 512
67 
68 static NBDExport *export;
69 static int verbose;
70 static char *srcpath;
71 static SocketAddress *saddr;
72 static int persistent = 0;
73 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
74 static int shared = 1;
75 static int nb_fds;
76 static QIONetListener *server;
77 static QCryptoTLSCreds *tlscreds;
78 static const char *tlsauthz;
79 
80 static void usage(const char *name)
81 {
82     (printf) (
83 "Usage: %s [OPTIONS] FILE\n"
84 "  or:  %s -L [OPTIONS]\n"
85 "QEMU Disk Network Block Device Utility\n"
86 "\n"
87 "  -h, --help                display this help and exit\n"
88 "  -V, --version             output version information and exit\n"
89 "\n"
90 "Connection properties:\n"
91 "  -p, --port=PORT           port to listen on (default `%d')\n"
92 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
93 "  -k, --socket=PATH         path to the unix socket\n"
94 "                            (default '"SOCKET_PATH"')\n"
95 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
96 "  -t, --persistent          don't exit on the last connection\n"
97 "  -v, --verbose             display extra debugging information\n"
98 "  -x, --export-name=NAME    expose export by name (default is empty string)\n"
99 "  -D, --description=TEXT    export a human-readable description\n"
100 "\n"
101 "Exposing part of the image:\n"
102 "  -o, --offset=OFFSET       offset into the image\n"
103 "  -B, --bitmap=NAME         expose a persistent dirty bitmap\n"
104 "\n"
105 "General purpose options:\n"
106 "  -L, --list                list exports available from another NBD server\n"
107 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
108 "                            passwords and/or encryption keys\n"
109 "  --tls-creds=ID            use id of an earlier --object to provide TLS\n"
110 "  --tls-authz=ID            use id of an earlier --object to provide\n"
111 "                            authorization\n"
112 "  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
113 "                            specify tracing options\n"
114 "  --fork                    fork off the server process and exit the parent\n"
115 "                            once the server is running\n"
116 "  --pid-file=PATH           store the server's process ID in the given file\n"
117 #if HAVE_NBD_DEVICE
118 "\n"
119 "Kernel NBD client support:\n"
120 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
121 "  -d, --disconnect          disconnect the specified device\n"
122 #endif
123 "\n"
124 "Block device options:\n"
125 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
126 "  -r, --read-only           export read-only\n"
127 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
128 "                            file with backing_file=FILE, redirect the write to\n"
129 "                            the temporary one\n"
130 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
131 "                            load an internal snapshot inside FILE and export it\n"
132 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
133 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
134 "                            '[ID_OR_NAME]'\n"
135 "  -n, --nocache             disable host cache\n"
136 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
137 "      --aio=MODE            set AIO mode (native, io_uring or threads)\n"
138 "      --discard=MODE        set discard mode (ignore, unmap)\n"
139 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
140 "      --image-opts          treat FILE as a full set of image options\n"
141 "\n"
142 QEMU_HELP_BOTTOM "\n"
143     , name, name, NBD_DEFAULT_PORT, "DEVICE");
144 }
145 
146 static void version(const char *name)
147 {
148     printf(
149 "%s " QEMU_FULL_VERSION "\n"
150 "Written by Anthony Liguori.\n"
151 "\n"
152 QEMU_COPYRIGHT "\n"
153 "This is free software; see the source for copying conditions.  There is NO\n"
154 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
155     , name);
156 }
157 
158 static void termsig_handler(int signum)
159 {
160     atomic_cmpxchg(&state, RUNNING, TERMINATE);
161     qemu_notify_event();
162 }
163 
164 
165 static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
166                                 const char *hostname)
167 {
168     int ret = EXIT_FAILURE;
169     int rc;
170     Error *err = NULL;
171     QIOChannelSocket *sioc;
172     NBDExportInfo *list;
173     int i, j;
174 
175     sioc = qio_channel_socket_new();
176     if (qio_channel_socket_connect_sync(sioc, saddr, &err) < 0) {
177         error_report_err(err);
178         return EXIT_FAILURE;
179     }
180     rc = nbd_receive_export_list(QIO_CHANNEL(sioc), tls, hostname, &list,
181                                  &err);
182     if (rc < 0) {
183         if (err) {
184             error_report_err(err);
185         }
186         goto out;
187     }
188     printf("exports available: %d\n", rc);
189     for (i = 0; i < rc; i++) {
190         printf(" export: '%s'\n", list[i].name);
191         if (list[i].description && *list[i].description) {
192             printf("  description: %s\n", list[i].description);
193         }
194         if (list[i].flags & NBD_FLAG_HAS_FLAGS) {
195             static const char *const flag_names[] = {
196                 [NBD_FLAG_READ_ONLY_BIT]            = "readonly",
197                 [NBD_FLAG_SEND_FLUSH_BIT]           = "flush",
198                 [NBD_FLAG_SEND_FUA_BIT]             = "fua",
199                 [NBD_FLAG_ROTATIONAL_BIT]           = "rotational",
200                 [NBD_FLAG_SEND_TRIM_BIT]            = "trim",
201                 [NBD_FLAG_SEND_WRITE_ZEROES_BIT]    = "zeroes",
202                 [NBD_FLAG_SEND_DF_BIT]              = "df",
203                 [NBD_FLAG_CAN_MULTI_CONN_BIT]       = "multi",
204                 [NBD_FLAG_SEND_RESIZE_BIT]          = "resize",
205                 [NBD_FLAG_SEND_CACHE_BIT]           = "cache",
206                 [NBD_FLAG_SEND_FAST_ZERO_BIT]       = "fast-zero",
207             };
208 
209             printf("  size:  %" PRIu64 "\n", list[i].size);
210             printf("  flags: 0x%x (", list[i].flags);
211             for (size_t bit = 0; bit < ARRAY_SIZE(flag_names); bit++) {
212                 if (flag_names[bit] && (list[i].flags & (1 << bit))) {
213                     printf(" %s", flag_names[bit]);
214                 }
215             }
216             printf(" )\n");
217         }
218         if (list[i].min_block) {
219             printf("  min block: %u\n", list[i].min_block);
220             printf("  opt block: %u\n", list[i].opt_block);
221             printf("  max block: %u\n", list[i].max_block);
222         }
223         if (list[i].n_contexts) {
224             printf("  available meta contexts: %d\n", list[i].n_contexts);
225             for (j = 0; j < list[i].n_contexts; j++) {
226                 printf("   %s\n", list[i].contexts[j]);
227             }
228         }
229     }
230     nbd_free_export_list(list, rc);
231 
232     ret = EXIT_SUCCESS;
233  out:
234     object_unref(OBJECT(sioc));
235     return ret;
236 }
237 
238 
239 #if HAVE_NBD_DEVICE
240 static void *show_parts(void *arg)
241 {
242     char *device = arg;
243     int nbd;
244 
245     /* linux just needs an open() to trigger
246      * the partition table update
247      * but remember to load the module with max_part != 0 :
248      *     modprobe nbd max_part=63
249      */
250     nbd = open(device, O_RDWR);
251     if (nbd >= 0) {
252         close(nbd);
253     }
254     return NULL;
255 }
256 
257 static void *nbd_client_thread(void *arg)
258 {
259     char *device = arg;
260     NBDExportInfo info = { .request_sizes = false, .name = g_strdup("") };
261     QIOChannelSocket *sioc;
262     int fd;
263     int ret;
264     pthread_t show_parts_thread;
265     Error *local_error = NULL;
266 
267     sioc = qio_channel_socket_new();
268     if (qio_channel_socket_connect_sync(sioc,
269                                         saddr,
270                                         &local_error) < 0) {
271         error_report_err(local_error);
272         goto out;
273     }
274 
275     ret = nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc),
276                                 NULL, NULL, NULL, &info, &local_error);
277     if (ret < 0) {
278         if (local_error) {
279             error_report_err(local_error);
280         }
281         goto out_socket;
282     }
283 
284     fd = open(device, O_RDWR);
285     if (fd < 0) {
286         /* Linux-only, we can use %m in printf.  */
287         error_report("Failed to open %s: %m", device);
288         goto out_socket;
289     }
290 
291     ret = nbd_init(fd, sioc, &info, &local_error);
292     if (ret < 0) {
293         error_report_err(local_error);
294         goto out_fd;
295     }
296 
297     /* update partition table */
298     pthread_create(&show_parts_thread, NULL, show_parts, device);
299 
300     if (verbose) {
301         fprintf(stderr, "NBD device %s is now connected to %s\n",
302                 device, srcpath);
303     } else {
304         /* Close stderr so that the qemu-nbd process exits.  */
305         dup2(STDOUT_FILENO, STDERR_FILENO);
306     }
307 
308     ret = nbd_client(fd);
309     if (ret) {
310         goto out_fd;
311     }
312     close(fd);
313     object_unref(OBJECT(sioc));
314     g_free(info.name);
315     kill(getpid(), SIGTERM);
316     return (void *) EXIT_SUCCESS;
317 
318 out_fd:
319     close(fd);
320 out_socket:
321     object_unref(OBJECT(sioc));
322 out:
323     g_free(info.name);
324     kill(getpid(), SIGTERM);
325     return (void *) EXIT_FAILURE;
326 }
327 #endif /* HAVE_NBD_DEVICE */
328 
329 static int nbd_can_accept(void)
330 {
331     return state == RUNNING && nb_fds < shared;
332 }
333 
334 static void nbd_export_closed(NBDExport *export)
335 {
336     assert(state == TERMINATING);
337     state = TERMINATED;
338 }
339 
340 static void nbd_update_server_watch(void);
341 
342 static void nbd_client_closed(NBDClient *client, bool negotiated)
343 {
344     nb_fds--;
345     if (negotiated && nb_fds == 0 && !persistent && state == RUNNING) {
346         state = TERMINATE;
347     }
348     nbd_update_server_watch();
349     nbd_client_put(client);
350 }
351 
352 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
353                        gpointer opaque)
354 {
355     if (state >= TERMINATE) {
356         return;
357     }
358 
359     nb_fds++;
360     nbd_update_server_watch();
361     nbd_client_new(cioc, tlscreds, tlsauthz, nbd_client_closed);
362 }
363 
364 static void nbd_update_server_watch(void)
365 {
366     if (nbd_can_accept()) {
367         qio_net_listener_set_client_func(server, nbd_accept, NULL, NULL);
368     } else {
369         qio_net_listener_set_client_func(server, NULL, NULL, NULL);
370     }
371 }
372 
373 
374 static SocketAddress *nbd_build_socket_address(const char *sockpath,
375                                                const char *bindto,
376                                                const char *port)
377 {
378     SocketAddress *saddr;
379 
380     saddr = g_new0(SocketAddress, 1);
381     if (sockpath) {
382         saddr->type = SOCKET_ADDRESS_TYPE_UNIX;
383         saddr->u.q_unix.path = g_strdup(sockpath);
384     } else {
385         InetSocketAddress *inet;
386         saddr->type = SOCKET_ADDRESS_TYPE_INET;
387         inet = &saddr->u.inet;
388         inet->host = g_strdup(bindto);
389         if (port) {
390             inet->port = g_strdup(port);
391         } else  {
392             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
393         }
394     }
395 
396     return saddr;
397 }
398 
399 
400 static QemuOptsList file_opts = {
401     .name = "file",
402     .implied_opt_name = "file",
403     .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
404     .desc = {
405         /* no elements => accept any params */
406         { /* end of list */ }
407     },
408 };
409 
410 static QemuOptsList qemu_object_opts = {
411     .name = "object",
412     .implied_opt_name = "qom-type",
413     .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
414     .desc = {
415         { }
416     },
417 };
418 
419 static bool qemu_nbd_object_print_help(const char *type, QemuOpts *opts)
420 {
421     if (user_creatable_print_help(type, opts)) {
422         exit(0);
423     }
424     return true;
425 }
426 
427 
428 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, bool list,
429                                           Error **errp)
430 {
431     Object *obj;
432     QCryptoTLSCreds *creds;
433 
434     obj = object_resolve_path_component(
435         object_get_objects_root(), id);
436     if (!obj) {
437         error_setg(errp, "No TLS credentials with id '%s'",
438                    id);
439         return NULL;
440     }
441     creds = (QCryptoTLSCreds *)
442         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
443     if (!creds) {
444         error_setg(errp, "Object with id '%s' is not TLS credentials",
445                    id);
446         return NULL;
447     }
448 
449     if (list) {
450         if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
451             error_setg(errp,
452                        "Expecting TLS credentials with a client endpoint");
453             return NULL;
454         }
455     } else {
456         if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
457             error_setg(errp,
458                        "Expecting TLS credentials with a server endpoint");
459             return NULL;
460         }
461     }
462     object_ref(obj);
463     return creds;
464 }
465 
466 static void setup_address_and_port(const char **address, const char **port)
467 {
468     if (*address == NULL) {
469         *address = "0.0.0.0";
470     }
471 
472     if (*port == NULL) {
473         *port = stringify(NBD_DEFAULT_PORT);
474     }
475 }
476 
477 /*
478  * Check socket parameters compatibility when socket activation is used.
479  */
480 static const char *socket_activation_validate_opts(const char *device,
481                                                    const char *sockpath,
482                                                    const char *address,
483                                                    const char *port,
484                                                    bool list)
485 {
486     if (device != NULL) {
487         return "NBD device can't be set when using socket activation";
488     }
489 
490     if (sockpath != NULL) {
491         return "Unix socket can't be set when using socket activation";
492     }
493 
494     if (address != NULL) {
495         return "The interface can't be set when using socket activation";
496     }
497 
498     if (port != NULL) {
499         return "TCP port number can't be set when using socket activation";
500     }
501 
502     if (list) {
503         return "List mode is incompatible with socket activation";
504     }
505 
506     return NULL;
507 }
508 
509 static void qemu_nbd_shutdown(void)
510 {
511     job_cancel_sync_all();
512     bdrv_close_all();
513 }
514 
515 int main(int argc, char **argv)
516 {
517     BlockBackend *blk;
518     BlockDriverState *bs;
519     uint64_t dev_offset = 0;
520     bool readonly = false;
521     bool disconnect = false;
522     const char *bindto = NULL;
523     const char *port = NULL;
524     char *sockpath = NULL;
525     char *device = NULL;
526     int64_t fd_size;
527     QemuOpts *sn_opts = NULL;
528     const char *sn_id_or_name = NULL;
529     const char *sopt = "hVb:o:p:rsnc:dvk:e:f:tl:x:T:D:B:L";
530     struct option lopt[] = {
531         { "help", no_argument, NULL, 'h' },
532         { "version", no_argument, NULL, 'V' },
533         { "bind", required_argument, NULL, 'b' },
534         { "port", required_argument, NULL, 'p' },
535         { "socket", required_argument, NULL, 'k' },
536         { "offset", required_argument, NULL, 'o' },
537         { "read-only", no_argument, NULL, 'r' },
538         { "bitmap", required_argument, NULL, 'B' },
539         { "connect", required_argument, NULL, 'c' },
540         { "disconnect", no_argument, NULL, 'd' },
541         { "list", no_argument, NULL, 'L' },
542         { "snapshot", no_argument, NULL, 's' },
543         { "load-snapshot", required_argument, NULL, 'l' },
544         { "nocache", no_argument, NULL, 'n' },
545         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
546         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
547         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
548         { "detect-zeroes", required_argument, NULL,
549           QEMU_NBD_OPT_DETECT_ZEROES },
550         { "shared", required_argument, NULL, 'e' },
551         { "format", required_argument, NULL, 'f' },
552         { "persistent", no_argument, NULL, 't' },
553         { "verbose", no_argument, NULL, 'v' },
554         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
555         { "export-name", required_argument, NULL, 'x' },
556         { "description", required_argument, NULL, 'D' },
557         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
558         { "tls-authz", required_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
559         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
560         { "trace", required_argument, NULL, 'T' },
561         { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
562         { "pid-file", required_argument, NULL, QEMU_NBD_OPT_PID_FILE },
563         { NULL, 0, NULL, 0 }
564     };
565     int ch;
566     int opt_ind = 0;
567     int flags = BDRV_O_RDWR;
568     int ret = 0;
569     bool seen_cache = false;
570     bool seen_discard = false;
571     bool seen_aio = false;
572     pthread_t client_thread;
573     const char *fmt = NULL;
574     Error *local_err = NULL;
575     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
576     QDict *options = NULL;
577     const char *export_name = NULL; /* defaults to "" later for server mode */
578     const char *export_description = NULL;
579     const char *bitmap = NULL;
580     const char *tlscredsid = NULL;
581     bool imageOpts = false;
582     bool writethrough = true;
583     char *trace_file = NULL;
584     bool fork_process = false;
585     bool list = false;
586     int old_stderr = -1;
587     unsigned socket_activation;
588     const char *pid_file_name = NULL;
589 
590     /* The client thread uses SIGTERM to interrupt the server.  A signal
591      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
592      */
593     struct sigaction sa_sigterm;
594     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
595     sa_sigterm.sa_handler = termsig_handler;
596     sigaction(SIGTERM, &sa_sigterm, NULL);
597 
598 #ifdef CONFIG_POSIX
599     signal(SIGPIPE, SIG_IGN);
600 #endif
601 
602     error_init(argv[0]);
603     module_call_init(MODULE_INIT_TRACE);
604     qcrypto_init(&error_fatal);
605 
606     module_call_init(MODULE_INIT_QOM);
607     qemu_add_opts(&qemu_object_opts);
608     qemu_add_opts(&qemu_trace_opts);
609     qemu_init_exec_dir(argv[0]);
610 
611     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
612         switch (ch) {
613         case 's':
614             flags |= BDRV_O_SNAPSHOT;
615             break;
616         case 'n':
617             optarg = (char *) "none";
618             /* fallthrough */
619         case QEMU_NBD_OPT_CACHE:
620             if (seen_cache) {
621                 error_report("-n and --cache can only be specified once");
622                 exit(EXIT_FAILURE);
623             }
624             seen_cache = true;
625             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
626                 error_report("Invalid cache mode `%s'", optarg);
627                 exit(EXIT_FAILURE);
628             }
629             break;
630         case QEMU_NBD_OPT_AIO:
631             if (seen_aio) {
632                 error_report("--aio can only be specified once");
633                 exit(EXIT_FAILURE);
634             }
635             seen_aio = true;
636             if (bdrv_parse_aio(optarg, &flags) < 0) {
637                 error_report("Invalid aio mode '%s'", optarg);
638                 exit(EXIT_FAILURE);
639             }
640             break;
641         case QEMU_NBD_OPT_DISCARD:
642             if (seen_discard) {
643                 error_report("--discard can only be specified once");
644                 exit(EXIT_FAILURE);
645             }
646             seen_discard = true;
647             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
648                 error_report("Invalid discard mode `%s'", optarg);
649                 exit(EXIT_FAILURE);
650             }
651             break;
652         case QEMU_NBD_OPT_DETECT_ZEROES:
653             detect_zeroes =
654                 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup,
655                                 optarg,
656                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
657                                 &local_err);
658             if (local_err) {
659                 error_reportf_err(local_err,
660                                   "Failed to parse detect_zeroes mode: ");
661                 exit(EXIT_FAILURE);
662             }
663             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
664                 !(flags & BDRV_O_UNMAP)) {
665                 error_report("setting detect-zeroes to unmap is not allowed "
666                              "without setting discard operation to unmap");
667                 exit(EXIT_FAILURE);
668             }
669             break;
670         case 'b':
671             bindto = optarg;
672             break;
673         case 'p':
674             port = optarg;
675             break;
676         case 'o':
677             if (qemu_strtou64(optarg, NULL, 0, &dev_offset) < 0) {
678                 error_report("Invalid offset '%s'", optarg);
679                 exit(EXIT_FAILURE);
680             }
681             break;
682         case 'l':
683             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
684                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
685                                                   optarg, false);
686                 if (!sn_opts) {
687                     error_report("Failed in parsing snapshot param `%s'",
688                                  optarg);
689                     exit(EXIT_FAILURE);
690                 }
691             } else {
692                 sn_id_or_name = optarg;
693             }
694             /* fall through */
695         case 'r':
696             readonly = true;
697             flags &= ~BDRV_O_RDWR;
698             break;
699         case 'B':
700             bitmap = optarg;
701             break;
702         case 'k':
703             sockpath = optarg;
704             if (sockpath[0] != '/') {
705                 error_report("socket path must be absolute");
706                 exit(EXIT_FAILURE);
707             }
708             break;
709         case 'd':
710             disconnect = true;
711             break;
712         case 'c':
713             device = optarg;
714             break;
715         case 'e':
716             if (qemu_strtoi(optarg, NULL, 0, &shared) < 0 ||
717                 shared < 1) {
718                 error_report("Invalid shared device number '%s'", optarg);
719                 exit(EXIT_FAILURE);
720             }
721             break;
722         case 'f':
723             fmt = optarg;
724             break;
725         case 't':
726             persistent = 1;
727             break;
728         case 'x':
729             export_name = optarg;
730             if (strlen(export_name) > NBD_MAX_STRING_SIZE) {
731                 error_report("export name '%s' too long", export_name);
732                 exit(EXIT_FAILURE);
733             }
734             break;
735         case 'D':
736             export_description = optarg;
737             if (strlen(export_description) > NBD_MAX_STRING_SIZE) {
738                 error_report("export description '%s' too long",
739                              export_description);
740                 exit(EXIT_FAILURE);
741             }
742             break;
743         case 'v':
744             verbose = 1;
745             break;
746         case 'V':
747             version(argv[0]);
748             exit(0);
749             break;
750         case 'h':
751             usage(argv[0]);
752             exit(0);
753             break;
754         case '?':
755             error_report("Try `%s --help' for more information.", argv[0]);
756             exit(EXIT_FAILURE);
757         case QEMU_NBD_OPT_OBJECT: {
758             QemuOpts *opts;
759             opts = qemu_opts_parse_noisily(&qemu_object_opts,
760                                            optarg, true);
761             if (!opts) {
762                 exit(EXIT_FAILURE);
763             }
764         }   break;
765         case QEMU_NBD_OPT_TLSCREDS:
766             tlscredsid = optarg;
767             break;
768         case QEMU_NBD_OPT_IMAGE_OPTS:
769             imageOpts = true;
770             break;
771         case 'T':
772             g_free(trace_file);
773             trace_file = trace_opt_parse(optarg);
774             break;
775         case QEMU_NBD_OPT_TLSAUTHZ:
776             tlsauthz = optarg;
777             break;
778         case QEMU_NBD_OPT_FORK:
779             fork_process = true;
780             break;
781         case 'L':
782             list = true;
783             break;
784         case QEMU_NBD_OPT_PID_FILE:
785             pid_file_name = optarg;
786             break;
787         }
788     }
789 
790     if (list) {
791         if (argc != optind) {
792             error_report("List mode is incompatible with a file name");
793             exit(EXIT_FAILURE);
794         }
795         if (export_name || export_description || dev_offset ||
796             device || disconnect || fmt || sn_id_or_name || bitmap ||
797             seen_aio || seen_discard || seen_cache) {
798             error_report("List mode is incompatible with per-device settings");
799             exit(EXIT_FAILURE);
800         }
801         if (fork_process) {
802             error_report("List mode is incompatible with forking");
803             exit(EXIT_FAILURE);
804         }
805     } else if ((argc - optind) != 1) {
806         error_report("Invalid number of arguments");
807         error_printf("Try `%s --help' for more information.\n", argv[0]);
808         exit(EXIT_FAILURE);
809     } else if (!export_name) {
810         export_name = "";
811     }
812 
813     qemu_opts_foreach(&qemu_object_opts,
814                       user_creatable_add_opts_foreach,
815                       qemu_nbd_object_print_help, &error_fatal);
816 
817     if (!trace_init_backends()) {
818         exit(1);
819     }
820     trace_init_file(trace_file);
821     qemu_set_log(LOG_TRACE);
822 
823     socket_activation = check_socket_activation();
824     if (socket_activation == 0) {
825         setup_address_and_port(&bindto, &port);
826     } else {
827         /* Using socket activation - check user didn't use -p etc. */
828         const char *err_msg = socket_activation_validate_opts(device, sockpath,
829                                                               bindto, port,
830                                                               list);
831         if (err_msg != NULL) {
832             error_report("%s", err_msg);
833             exit(EXIT_FAILURE);
834         }
835 
836         /* qemu-nbd can only listen on a single socket.  */
837         if (socket_activation > 1) {
838             error_report("qemu-nbd does not support socket activation with %s > 1",
839                          "LISTEN_FDS");
840             exit(EXIT_FAILURE);
841         }
842     }
843 
844     if (tlscredsid) {
845         if (sockpath) {
846             error_report("TLS is only supported with IPv4/IPv6");
847             exit(EXIT_FAILURE);
848         }
849         if (device) {
850             error_report("TLS is not supported with a host device");
851             exit(EXIT_FAILURE);
852         }
853         if (tlsauthz && list) {
854             error_report("TLS authorization is incompatible with export list");
855             exit(EXIT_FAILURE);
856         }
857         tlscreds = nbd_get_tls_creds(tlscredsid, list, &local_err);
858         if (local_err) {
859             error_report("Failed to get TLS creds %s",
860                          error_get_pretty(local_err));
861             exit(EXIT_FAILURE);
862         }
863     } else {
864         if (tlsauthz) {
865             error_report("--tls-authz is not permitted without --tls-creds");
866             exit(EXIT_FAILURE);
867         }
868     }
869 
870     if (list) {
871         saddr = nbd_build_socket_address(sockpath, bindto, port);
872         return qemu_nbd_client_list(saddr, tlscreds, bindto);
873     }
874 
875 #if !HAVE_NBD_DEVICE
876     if (disconnect || device) {
877         error_report("Kernel /dev/nbdN support not available");
878         exit(EXIT_FAILURE);
879     }
880 #else /* HAVE_NBD_DEVICE */
881     if (disconnect) {
882         int nbdfd = open(argv[optind], O_RDWR);
883         if (nbdfd < 0) {
884             error_report("Cannot open %s: %s", argv[optind],
885                          strerror(errno));
886             exit(EXIT_FAILURE);
887         }
888         nbd_disconnect(nbdfd);
889 
890         close(nbdfd);
891 
892         printf("%s disconnected\n", argv[optind]);
893 
894         return 0;
895     }
896 #endif
897 
898     if ((device && !verbose) || fork_process) {
899         int stderr_fd[2];
900         pid_t pid;
901         int ret;
902 
903         if (qemu_pipe(stderr_fd) < 0) {
904             error_report("Error setting up communication pipe: %s",
905                          strerror(errno));
906             exit(EXIT_FAILURE);
907         }
908 
909         /* Now daemonize, but keep a communication channel open to
910          * print errors and exit with the proper status code.
911          */
912         pid = fork();
913         if (pid < 0) {
914             error_report("Failed to fork: %s", strerror(errno));
915             exit(EXIT_FAILURE);
916         } else if (pid == 0) {
917             close(stderr_fd[0]);
918 
919             old_stderr = dup(STDERR_FILENO);
920             ret = qemu_daemon(1, 0);
921 
922             /* Temporarily redirect stderr to the parent's pipe...  */
923             dup2(stderr_fd[1], STDERR_FILENO);
924             if (ret < 0) {
925                 error_report("Failed to daemonize: %s", strerror(errno));
926                 exit(EXIT_FAILURE);
927             }
928 
929             /* ... close the descriptor we inherited and go on.  */
930             close(stderr_fd[1]);
931         } else {
932             bool errors = false;
933             char *buf;
934 
935             /* In the parent.  Print error messages from the child until
936              * it closes the pipe.
937              */
938             close(stderr_fd[1]);
939             buf = g_malloc(1024);
940             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
941                 errors = true;
942                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
943                 if (ret < 0) {
944                     exit(EXIT_FAILURE);
945                 }
946             }
947             if (ret < 0) {
948                 error_report("Cannot read from daemon: %s",
949                              strerror(errno));
950                 exit(EXIT_FAILURE);
951             }
952 
953             /* Usually the daemon should not print any message.
954              * Exit with zero status in that case.
955              */
956             exit(errors);
957         }
958     }
959 
960     if (device != NULL && sockpath == NULL) {
961         sockpath = g_malloc(128);
962         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
963     }
964 
965     server = qio_net_listener_new();
966     if (socket_activation == 0) {
967         saddr = nbd_build_socket_address(sockpath, bindto, port);
968         if (qio_net_listener_open_sync(server, saddr, 1, &local_err) < 0) {
969             object_unref(OBJECT(server));
970             error_report_err(local_err);
971             exit(EXIT_FAILURE);
972         }
973     } else {
974         size_t i;
975         /* See comment in check_socket_activation above. */
976         for (i = 0; i < socket_activation; i++) {
977             QIOChannelSocket *sioc;
978             sioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD + i,
979                                              &local_err);
980             if (sioc == NULL) {
981                 object_unref(OBJECT(server));
982                 error_report("Failed to use socket activation: %s",
983                              error_get_pretty(local_err));
984                 exit(EXIT_FAILURE);
985             }
986             qio_net_listener_add(server, sioc);
987             object_unref(OBJECT(sioc));
988         }
989     }
990 
991     if (qemu_init_main_loop(&local_err)) {
992         error_report_err(local_err);
993         exit(EXIT_FAILURE);
994     }
995     bdrv_init();
996     atexit(qemu_nbd_shutdown);
997 
998     srcpath = argv[optind];
999     if (imageOpts) {
1000         QemuOpts *opts;
1001         if (fmt) {
1002             error_report("--image-opts and -f are mutually exclusive");
1003             exit(EXIT_FAILURE);
1004         }
1005         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
1006         if (!opts) {
1007             qemu_opts_reset(&file_opts);
1008             exit(EXIT_FAILURE);
1009         }
1010         options = qemu_opts_to_qdict(opts, NULL);
1011         qemu_opts_reset(&file_opts);
1012         blk = blk_new_open(NULL, NULL, options, flags, &local_err);
1013     } else {
1014         if (fmt) {
1015             options = qdict_new();
1016             qdict_put_str(options, "driver", fmt);
1017         }
1018         blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
1019     }
1020 
1021     if (!blk) {
1022         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
1023                           argv[optind]);
1024         exit(EXIT_FAILURE);
1025     }
1026     bs = blk_bs(blk);
1027 
1028     blk_set_enable_write_cache(blk, !writethrough);
1029 
1030     if (sn_opts) {
1031         ret = bdrv_snapshot_load_tmp(bs,
1032                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
1033                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
1034                                      &local_err);
1035     } else if (sn_id_or_name) {
1036         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
1037                                                    &local_err);
1038     }
1039     if (ret < 0) {
1040         error_reportf_err(local_err, "Failed to load snapshot: ");
1041         exit(EXIT_FAILURE);
1042     }
1043 
1044     bs->detect_zeroes = detect_zeroes;
1045     fd_size = blk_getlength(blk);
1046     if (fd_size < 0) {
1047         error_report("Failed to determine the image length: %s",
1048                      strerror(-fd_size));
1049         exit(EXIT_FAILURE);
1050     }
1051 
1052     if (dev_offset >= fd_size) {
1053         error_report("Offset (%" PRIu64 ") has to be smaller than the image "
1054                      "size (%" PRId64 ")", dev_offset, fd_size);
1055         exit(EXIT_FAILURE);
1056     }
1057     fd_size -= dev_offset;
1058 
1059     export = nbd_export_new(bs, dev_offset, fd_size, export_name,
1060                             export_description, bitmap, readonly, shared > 1,
1061                             nbd_export_closed, writethrough, NULL,
1062                             &error_fatal);
1063 
1064     if (device) {
1065 #if HAVE_NBD_DEVICE
1066         int ret;
1067 
1068         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
1069         if (ret != 0) {
1070             error_report("Failed to create client thread: %s", strerror(ret));
1071             exit(EXIT_FAILURE);
1072         }
1073 #endif
1074     } else {
1075         /* Shut up GCC warnings.  */
1076         memset(&client_thread, 0, sizeof(client_thread));
1077     }
1078 
1079     nbd_update_server_watch();
1080 
1081     if (pid_file_name) {
1082         qemu_write_pidfile(pid_file_name, &error_fatal);
1083     }
1084 
1085     /* now when the initialization is (almost) complete, chdir("/")
1086      * to free any busy filesystems */
1087     if (chdir("/") < 0) {
1088         error_report("Could not chdir to root directory: %s",
1089                      strerror(errno));
1090         exit(EXIT_FAILURE);
1091     }
1092 
1093     if (fork_process) {
1094         dup2(old_stderr, STDERR_FILENO);
1095         close(old_stderr);
1096     }
1097 
1098     state = RUNNING;
1099     do {
1100         main_loop_wait(false);
1101         if (state == TERMINATE) {
1102             state = TERMINATING;
1103             nbd_export_close(export);
1104             nbd_export_put(export);
1105             export = NULL;
1106         }
1107     } while (state != TERMINATED);
1108 
1109     blk_unref(blk);
1110     if (sockpath) {
1111         unlink(sockpath);
1112     }
1113 
1114     qemu_opts_del(sn_opts);
1115 
1116     if (device) {
1117         void *ret;
1118         pthread_join(client_thread, &ret);
1119         exit(ret != NULL);
1120     } else {
1121         exit(EXIT_SUCCESS);
1122     }
1123 }
1124