xref: /openbmc/qemu/qemu-nbd.c (revision c97d6d2c)
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 "qapi/error.h"
25 #include "qemu-common.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/error-report.h"
32 #include "qemu/config-file.h"
33 #include "qemu/bswap.h"
34 #include "qemu/log.h"
35 #include "qemu/systemd.h"
36 #include "block/snapshot.h"
37 #include "qapi/qmp/qstring.h"
38 #include "qom/object_interfaces.h"
39 #include "io/channel-socket.h"
40 #include "io/net-listener.h"
41 #include "crypto/init.h"
42 #include "trace/control.h"
43 #include "qemu-version.h"
44 
45 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
46 #define QEMU_NBD_OPT_CACHE         256
47 #define QEMU_NBD_OPT_AIO           257
48 #define QEMU_NBD_OPT_DISCARD       258
49 #define QEMU_NBD_OPT_DETECT_ZEROES 259
50 #define QEMU_NBD_OPT_OBJECT        260
51 #define QEMU_NBD_OPT_TLSCREDS      261
52 #define QEMU_NBD_OPT_IMAGE_OPTS    262
53 #define QEMU_NBD_OPT_FORK          263
54 
55 #define MBR_SIZE 512
56 
57 static NBDExport *exp;
58 static bool newproto;
59 static int verbose;
60 static char *srcpath;
61 static SocketAddress *saddr;
62 static int persistent = 0;
63 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
64 static int shared = 1;
65 static int nb_fds;
66 static QIONetListener *server;
67 static QCryptoTLSCreds *tlscreds;
68 
69 static void usage(const char *name)
70 {
71     (printf) (
72 "Usage: %s [OPTIONS] FILE\n"
73 "QEMU Disk Network Block Device Server\n"
74 "\n"
75 "  -h, --help                display this help and exit\n"
76 "  -V, --version             output version information and exit\n"
77 "\n"
78 "Connection properties:\n"
79 "  -p, --port=PORT           port to listen on (default `%d')\n"
80 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
81 "  -k, --socket=PATH         path to the unix socket\n"
82 "                            (default '"SOCKET_PATH"')\n"
83 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
84 "  -t, --persistent          don't exit on the last connection\n"
85 "  -v, --verbose             display extra debugging information\n"
86 "  -x, --export-name=NAME    expose export by name\n"
87 "  -D, --description=TEXT    with -x, also export a human-readable description\n"
88 "\n"
89 "Exposing part of the image:\n"
90 "  -o, --offset=OFFSET       offset into the image\n"
91 "  -P, --partition=NUM       only expose partition NUM\n"
92 "\n"
93 "General purpose options:\n"
94 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
95 "                            passwords and/or encryption keys\n"
96 "  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
97 "                            specify tracing options\n"
98 "  --fork                    fork off the server process and exit the parent\n"
99 "                            once the server is running\n"
100 #ifdef __linux__
101 "Kernel NBD client support:\n"
102 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
103 "  -d, --disconnect          disconnect the specified device\n"
104 "\n"
105 #endif
106 "\n"
107 "Block device options:\n"
108 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
109 "  -r, --read-only           export read-only\n"
110 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
111 "                            file with backing_file=FILE, redirect the write to\n"
112 "                            the temporary one\n"
113 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
114 "                            load an internal snapshot inside FILE and export it\n"
115 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
116 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
117 "                            '[ID_OR_NAME]'\n"
118 "  -n, --nocache             disable host cache\n"
119 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
120 "      --aio=MODE            set AIO mode (native or threads)\n"
121 "      --discard=MODE        set discard mode (ignore, unmap)\n"
122 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
123 "      --image-opts          treat FILE as a full set of image options\n"
124 "\n"
125 QEMU_HELP_BOTTOM "\n"
126     , name, NBD_DEFAULT_PORT, "DEVICE");
127 }
128 
129 static void version(const char *name)
130 {
131     printf(
132 "%s " QEMU_VERSION QEMU_PKGVERSION "\n"
133 "Written by Anthony Liguori.\n"
134 "\n"
135 QEMU_COPYRIGHT "\n"
136 "This is free software; see the source for copying conditions.  There is NO\n"
137 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
138     , name);
139 }
140 
141 struct partition_record
142 {
143     uint8_t bootable;
144     uint8_t start_head;
145     uint32_t start_cylinder;
146     uint8_t start_sector;
147     uint8_t system;
148     uint8_t end_head;
149     uint8_t end_cylinder;
150     uint8_t end_sector;
151     uint32_t start_sector_abs;
152     uint32_t nb_sectors_abs;
153 };
154 
155 static void read_partition(uint8_t *p, struct partition_record *r)
156 {
157     r->bootable = p[0];
158     r->start_head = p[1];
159     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
160     r->start_sector = p[2] & 0x3f;
161     r->system = p[4];
162     r->end_head = p[5];
163     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
164     r->end_sector = p[6] & 0x3f;
165 
166     r->start_sector_abs = ldl_le_p(p + 8);
167     r->nb_sectors_abs   = ldl_le_p(p + 12);
168 }
169 
170 static int find_partition(BlockBackend *blk, int partition,
171                           off_t *offset, off_t *size)
172 {
173     struct partition_record mbr[4];
174     uint8_t data[MBR_SIZE];
175     int i;
176     int ext_partnum = 4;
177     int ret;
178 
179     ret = blk_pread(blk, 0, data, sizeof(data));
180     if (ret < 0) {
181         error_report("error while reading: %s", strerror(-ret));
182         exit(EXIT_FAILURE);
183     }
184 
185     if (data[510] != 0x55 || data[511] != 0xaa) {
186         return -EINVAL;
187     }
188 
189     for (i = 0; i < 4; i++) {
190         read_partition(&data[446 + 16 * i], &mbr[i]);
191 
192         if (!mbr[i].system || !mbr[i].nb_sectors_abs) {
193             continue;
194         }
195 
196         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
197             struct partition_record ext[4];
198             uint8_t data1[MBR_SIZE];
199             int j;
200 
201             ret = blk_pread(blk, mbr[i].start_sector_abs * MBR_SIZE,
202                             data1, sizeof(data1));
203             if (ret < 0) {
204                 error_report("error while reading: %s", strerror(-ret));
205                 exit(EXIT_FAILURE);
206             }
207 
208             for (j = 0; j < 4; j++) {
209                 read_partition(&data1[446 + 16 * j], &ext[j]);
210                 if (!ext[j].system || !ext[j].nb_sectors_abs) {
211                     continue;
212                 }
213 
214                 if ((ext_partnum + j + 1) == partition) {
215                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
216                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
217                     return 0;
218                 }
219             }
220             ext_partnum += 4;
221         } else if ((i + 1) == partition) {
222             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
223             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
224             return 0;
225         }
226     }
227 
228     return -ENOENT;
229 }
230 
231 static void termsig_handler(int signum)
232 {
233     atomic_cmpxchg(&state, RUNNING, TERMINATE);
234     qemu_notify_event();
235 }
236 
237 
238 static void *show_parts(void *arg)
239 {
240     char *device = arg;
241     int nbd;
242 
243     /* linux just needs an open() to trigger
244      * the partition table update
245      * but remember to load the module with max_part != 0 :
246      *     modprobe nbd max_part=63
247      */
248     nbd = open(device, O_RDWR);
249     if (nbd >= 0) {
250         close(nbd);
251     }
252     return NULL;
253 }
254 
255 static void *nbd_client_thread(void *arg)
256 {
257     char *device = arg;
258     NBDExportInfo info = { .request_sizes = false, };
259     QIOChannelSocket *sioc;
260     int fd;
261     int ret;
262     pthread_t show_parts_thread;
263     Error *local_error = NULL;
264 
265     sioc = qio_channel_socket_new();
266     if (qio_channel_socket_connect_sync(sioc,
267                                         saddr,
268                                         &local_error) < 0) {
269         error_report_err(local_error);
270         goto out;
271     }
272 
273     ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), NULL,
274                                 NULL, NULL, NULL, &info, &local_error);
275     if (ret < 0) {
276         if (local_error) {
277             error_report_err(local_error);
278         }
279         goto out_socket;
280     }
281 
282     fd = open(device, O_RDWR);
283     if (fd < 0) {
284         /* Linux-only, we can use %m in printf.  */
285         error_report("Failed to open %s: %m", device);
286         goto out_socket;
287     }
288 
289     ret = nbd_init(fd, sioc, &info, &local_error);
290     if (ret < 0) {
291         error_report_err(local_error);
292         goto out_fd;
293     }
294 
295     /* update partition table */
296     pthread_create(&show_parts_thread, NULL, show_parts, device);
297 
298     if (verbose) {
299         fprintf(stderr, "NBD device %s is now connected to %s\n",
300                 device, srcpath);
301     } else {
302         /* Close stderr so that the qemu-nbd process exits.  */
303         dup2(STDOUT_FILENO, STDERR_FILENO);
304     }
305 
306     ret = nbd_client(fd);
307     if (ret) {
308         goto out_fd;
309     }
310     close(fd);
311     object_unref(OBJECT(sioc));
312     kill(getpid(), SIGTERM);
313     return (void *) EXIT_SUCCESS;
314 
315 out_fd:
316     close(fd);
317 out_socket:
318     object_unref(OBJECT(sioc));
319 out:
320     kill(getpid(), SIGTERM);
321     return (void *) EXIT_FAILURE;
322 }
323 
324 static int nbd_can_accept(void)
325 {
326     return state == RUNNING && nb_fds < shared;
327 }
328 
329 static void nbd_export_closed(NBDExport *exp)
330 {
331     assert(state == TERMINATING);
332     state = TERMINATED;
333 }
334 
335 static void nbd_update_server_watch(void);
336 
337 static void nbd_client_closed(NBDClient *client, bool negotiated)
338 {
339     nb_fds--;
340     if (negotiated && nb_fds == 0 && !persistent && state == RUNNING) {
341         state = TERMINATE;
342     }
343     nbd_update_server_watch();
344     nbd_client_put(client);
345 }
346 
347 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
348                        gpointer opaque)
349 {
350     if (state >= TERMINATE) {
351         return;
352     }
353 
354     nb_fds++;
355     nbd_update_server_watch();
356     nbd_client_new(newproto ? NULL : exp, cioc,
357                    tlscreds, NULL, nbd_client_closed);
358 }
359 
360 static void nbd_update_server_watch(void)
361 {
362     if (nbd_can_accept()) {
363         qio_net_listener_set_client_func(server, nbd_accept, NULL, NULL);
364     } else {
365         qio_net_listener_set_client_func(server, NULL, NULL, NULL);
366     }
367 }
368 
369 
370 static SocketAddress *nbd_build_socket_address(const char *sockpath,
371                                                const char *bindto,
372                                                const char *port)
373 {
374     SocketAddress *saddr;
375 
376     saddr = g_new0(SocketAddress, 1);
377     if (sockpath) {
378         saddr->type = SOCKET_ADDRESS_TYPE_UNIX;
379         saddr->u.q_unix.path = g_strdup(sockpath);
380     } else {
381         InetSocketAddress *inet;
382         saddr->type = SOCKET_ADDRESS_TYPE_INET;
383         inet = &saddr->u.inet;
384         inet->host = g_strdup(bindto);
385         if (port) {
386             inet->port = g_strdup(port);
387         } else  {
388             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
389         }
390     }
391 
392     return saddr;
393 }
394 
395 
396 static QemuOptsList file_opts = {
397     .name = "file",
398     .implied_opt_name = "file",
399     .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
400     .desc = {
401         /* no elements => accept any params */
402         { /* end of list */ }
403     },
404 };
405 
406 static QemuOptsList qemu_object_opts = {
407     .name = "object",
408     .implied_opt_name = "qom-type",
409     .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
410     .desc = {
411         { }
412     },
413 };
414 
415 
416 
417 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
418 {
419     Object *obj;
420     QCryptoTLSCreds *creds;
421 
422     obj = object_resolve_path_component(
423         object_get_objects_root(), id);
424     if (!obj) {
425         error_setg(errp, "No TLS credentials with id '%s'",
426                    id);
427         return NULL;
428     }
429     creds = (QCryptoTLSCreds *)
430         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
431     if (!creds) {
432         error_setg(errp, "Object with id '%s' is not TLS credentials",
433                    id);
434         return NULL;
435     }
436 
437     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
438         error_setg(errp,
439                    "Expecting TLS credentials with a server endpoint");
440         return NULL;
441     }
442     object_ref(obj);
443     return creds;
444 }
445 
446 static void setup_address_and_port(const char **address, const char **port)
447 {
448     if (*address == NULL) {
449         *address = "0.0.0.0";
450     }
451 
452     if (*port == NULL) {
453         *port = stringify(NBD_DEFAULT_PORT);
454     }
455 }
456 
457 /*
458  * Check socket parameters compatibility when socket activation is used.
459  */
460 static const char *socket_activation_validate_opts(const char *device,
461                                                    const char *sockpath,
462                                                    const char *address,
463                                                    const char *port)
464 {
465     if (device != NULL) {
466         return "NBD device can't be set when using socket activation";
467     }
468 
469     if (sockpath != NULL) {
470         return "Unix socket can't be set when using socket activation";
471     }
472 
473     if (address != NULL) {
474         return "The interface can't be set when using socket activation";
475     }
476 
477     if (port != NULL) {
478         return "TCP port number can't be set when using socket activation";
479     }
480 
481     return NULL;
482 }
483 
484 int main(int argc, char **argv)
485 {
486     BlockBackend *blk;
487     BlockDriverState *bs;
488     off_t dev_offset = 0;
489     uint16_t nbdflags = 0;
490     bool disconnect = false;
491     const char *bindto = NULL;
492     const char *port = NULL;
493     char *sockpath = NULL;
494     char *device = NULL;
495     off_t fd_size;
496     QemuOpts *sn_opts = NULL;
497     const char *sn_id_or_name = NULL;
498     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:";
499     struct option lopt[] = {
500         { "help", no_argument, NULL, 'h' },
501         { "version", no_argument, NULL, 'V' },
502         { "bind", required_argument, NULL, 'b' },
503         { "port", required_argument, NULL, 'p' },
504         { "socket", required_argument, NULL, 'k' },
505         { "offset", required_argument, NULL, 'o' },
506         { "read-only", no_argument, NULL, 'r' },
507         { "partition", required_argument, NULL, 'P' },
508         { "connect", required_argument, NULL, 'c' },
509         { "disconnect", no_argument, NULL, 'd' },
510         { "snapshot", no_argument, NULL, 's' },
511         { "load-snapshot", required_argument, NULL, 'l' },
512         { "nocache", no_argument, NULL, 'n' },
513         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
514         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
515         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
516         { "detect-zeroes", required_argument, NULL,
517           QEMU_NBD_OPT_DETECT_ZEROES },
518         { "shared", required_argument, NULL, 'e' },
519         { "format", required_argument, NULL, 'f' },
520         { "persistent", no_argument, NULL, 't' },
521         { "verbose", no_argument, NULL, 'v' },
522         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
523         { "export-name", required_argument, NULL, 'x' },
524         { "description", required_argument, NULL, 'D' },
525         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
526         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
527         { "trace", required_argument, NULL, 'T' },
528         { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
529         { NULL, 0, NULL, 0 }
530     };
531     int ch;
532     int opt_ind = 0;
533     char *end;
534     int flags = BDRV_O_RDWR;
535     int partition = -1;
536     int ret = 0;
537     bool seen_cache = false;
538     bool seen_discard = false;
539     bool seen_aio = false;
540     pthread_t client_thread;
541     const char *fmt = NULL;
542     Error *local_err = NULL;
543     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
544     QDict *options = NULL;
545     const char *export_name = NULL;
546     const char *export_description = NULL;
547     const char *tlscredsid = NULL;
548     bool imageOpts = false;
549     bool writethrough = true;
550     char *trace_file = NULL;
551     bool fork_process = false;
552     int old_stderr = -1;
553     unsigned socket_activation;
554 
555     /* The client thread uses SIGTERM to interrupt the server.  A signal
556      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
557      */
558     struct sigaction sa_sigterm;
559     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
560     sa_sigterm.sa_handler = termsig_handler;
561     sigaction(SIGTERM, &sa_sigterm, NULL);
562 
563 #ifdef CONFIG_POSIX
564     signal(SIGPIPE, SIG_IGN);
565 #endif
566 
567     module_call_init(MODULE_INIT_TRACE);
568     qcrypto_init(&error_fatal);
569 
570     module_call_init(MODULE_INIT_QOM);
571     qemu_add_opts(&qemu_object_opts);
572     qemu_add_opts(&qemu_trace_opts);
573     qemu_init_exec_dir(argv[0]);
574 
575     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
576         switch (ch) {
577         case 's':
578             flags |= BDRV_O_SNAPSHOT;
579             break;
580         case 'n':
581             optarg = (char *) "none";
582             /* fallthrough */
583         case QEMU_NBD_OPT_CACHE:
584             if (seen_cache) {
585                 error_report("-n and --cache can only be specified once");
586                 exit(EXIT_FAILURE);
587             }
588             seen_cache = true;
589             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
590                 error_report("Invalid cache mode `%s'", optarg);
591                 exit(EXIT_FAILURE);
592             }
593             break;
594         case QEMU_NBD_OPT_AIO:
595             if (seen_aio) {
596                 error_report("--aio can only be specified once");
597                 exit(EXIT_FAILURE);
598             }
599             seen_aio = true;
600             if (!strcmp(optarg, "native")) {
601                 flags |= BDRV_O_NATIVE_AIO;
602             } else if (!strcmp(optarg, "threads")) {
603                 /* this is the default */
604             } else {
605                error_report("invalid aio mode `%s'", optarg);
606                exit(EXIT_FAILURE);
607             }
608             break;
609         case QEMU_NBD_OPT_DISCARD:
610             if (seen_discard) {
611                 error_report("--discard can only be specified once");
612                 exit(EXIT_FAILURE);
613             }
614             seen_discard = true;
615             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
616                 error_report("Invalid discard mode `%s'", optarg);
617                 exit(EXIT_FAILURE);
618             }
619             break;
620         case QEMU_NBD_OPT_DETECT_ZEROES:
621             detect_zeroes =
622                 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup,
623                                 optarg,
624                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
625                                 &local_err);
626             if (local_err) {
627                 error_reportf_err(local_err,
628                                   "Failed to parse detect_zeroes mode: ");
629                 exit(EXIT_FAILURE);
630             }
631             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
632                 !(flags & BDRV_O_UNMAP)) {
633                 error_report("setting detect-zeroes to unmap is not allowed "
634                              "without setting discard operation to unmap");
635                 exit(EXIT_FAILURE);
636             }
637             break;
638         case 'b':
639             bindto = optarg;
640             break;
641         case 'p':
642             port = optarg;
643             break;
644         case 'o':
645                 dev_offset = strtoll (optarg, &end, 0);
646             if (*end) {
647                 error_report("Invalid offset `%s'", optarg);
648                 exit(EXIT_FAILURE);
649             }
650             if (dev_offset < 0) {
651                 error_report("Offset must be positive `%s'", optarg);
652                 exit(EXIT_FAILURE);
653             }
654             break;
655         case 'l':
656             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
657                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
658                                                   optarg, false);
659                 if (!sn_opts) {
660                     error_report("Failed in parsing snapshot param `%s'",
661                                  optarg);
662                     exit(EXIT_FAILURE);
663                 }
664             } else {
665                 sn_id_or_name = optarg;
666             }
667             /* fall through */
668         case 'r':
669             nbdflags |= NBD_FLAG_READ_ONLY;
670             flags &= ~BDRV_O_RDWR;
671             break;
672         case 'P':
673             partition = strtol(optarg, &end, 0);
674             if (*end) {
675                 error_report("Invalid partition `%s'", optarg);
676                 exit(EXIT_FAILURE);
677             }
678             if (partition < 1 || partition > 8) {
679                 error_report("Invalid partition %d", partition);
680                 exit(EXIT_FAILURE);
681             }
682             break;
683         case 'k':
684             sockpath = optarg;
685             if (sockpath[0] != '/') {
686                 error_report("socket path must be absolute");
687                 exit(EXIT_FAILURE);
688             }
689             break;
690         case 'd':
691             disconnect = true;
692             break;
693         case 'c':
694             device = optarg;
695             break;
696         case 'e':
697             shared = strtol(optarg, &end, 0);
698             if (*end) {
699                 error_report("Invalid shared device number '%s'", optarg);
700                 exit(EXIT_FAILURE);
701             }
702             if (shared < 1) {
703                 error_report("Shared device number must be greater than 0");
704                 exit(EXIT_FAILURE);
705             }
706             break;
707         case 'f':
708             fmt = optarg;
709             break;
710         case 't':
711             persistent = 1;
712             break;
713         case 'x':
714             export_name = optarg;
715             break;
716         case 'D':
717             export_description = optarg;
718             break;
719         case 'v':
720             verbose = 1;
721             break;
722         case 'V':
723             version(argv[0]);
724             exit(0);
725             break;
726         case 'h':
727             usage(argv[0]);
728             exit(0);
729             break;
730         case '?':
731             error_report("Try `%s --help' for more information.", argv[0]);
732             exit(EXIT_FAILURE);
733         case QEMU_NBD_OPT_OBJECT: {
734             QemuOpts *opts;
735             opts = qemu_opts_parse_noisily(&qemu_object_opts,
736                                            optarg, true);
737             if (!opts) {
738                 exit(EXIT_FAILURE);
739             }
740         }   break;
741         case QEMU_NBD_OPT_TLSCREDS:
742             tlscredsid = optarg;
743             break;
744         case QEMU_NBD_OPT_IMAGE_OPTS:
745             imageOpts = true;
746             break;
747         case 'T':
748             g_free(trace_file);
749             trace_file = trace_opt_parse(optarg);
750             break;
751         case QEMU_NBD_OPT_FORK:
752             fork_process = true;
753             break;
754         }
755     }
756 
757     if ((argc - optind) != 1) {
758         error_report("Invalid number of arguments");
759         error_printf("Try `%s --help' for more information.\n", argv[0]);
760         exit(EXIT_FAILURE);
761     }
762 
763     if (qemu_opts_foreach(&qemu_object_opts,
764                           user_creatable_add_opts_foreach,
765                           NULL, NULL)) {
766         exit(EXIT_FAILURE);
767     }
768 
769     if (!trace_init_backends()) {
770         exit(1);
771     }
772     trace_init_file(trace_file);
773     qemu_set_log(LOG_TRACE);
774 
775     socket_activation = check_socket_activation();
776     if (socket_activation == 0) {
777         setup_address_and_port(&bindto, &port);
778     } else {
779         /* Using socket activation - check user didn't use -p etc. */
780         const char *err_msg = socket_activation_validate_opts(device, sockpath,
781                                                               bindto, port);
782         if (err_msg != NULL) {
783             error_report("%s", err_msg);
784             exit(EXIT_FAILURE);
785         }
786 
787         /* qemu-nbd can only listen on a single socket.  */
788         if (socket_activation > 1) {
789             error_report("qemu-nbd does not support socket activation with %s > 1",
790                          "LISTEN_FDS");
791             exit(EXIT_FAILURE);
792         }
793     }
794 
795     if (tlscredsid) {
796         if (sockpath) {
797             error_report("TLS is only supported with IPv4/IPv6");
798             exit(EXIT_FAILURE);
799         }
800         if (device) {
801             error_report("TLS is not supported with a host device");
802             exit(EXIT_FAILURE);
803         }
804         if (!export_name) {
805             /* Set the default NBD protocol export name, since
806              * we *must* use new style protocol for TLS */
807             export_name = "";
808         }
809         tlscreds = nbd_get_tls_creds(tlscredsid, &local_err);
810         if (local_err) {
811             error_report("Failed to get TLS creds %s",
812                          error_get_pretty(local_err));
813             exit(EXIT_FAILURE);
814         }
815     }
816 
817     if (disconnect) {
818         int nbdfd = open(argv[optind], O_RDWR);
819         if (nbdfd < 0) {
820             error_report("Cannot open %s: %s", argv[optind],
821                          strerror(errno));
822             exit(EXIT_FAILURE);
823         }
824         nbd_disconnect(nbdfd);
825 
826         close(nbdfd);
827 
828         printf("%s disconnected\n", argv[optind]);
829 
830         return 0;
831     }
832 
833     if ((device && !verbose) || fork_process) {
834         int stderr_fd[2];
835         pid_t pid;
836         int ret;
837 
838         if (qemu_pipe(stderr_fd) < 0) {
839             error_report("Error setting up communication pipe: %s",
840                          strerror(errno));
841             exit(EXIT_FAILURE);
842         }
843 
844         /* Now daemonize, but keep a communication channel open to
845          * print errors and exit with the proper status code.
846          */
847         pid = fork();
848         if (pid < 0) {
849             error_report("Failed to fork: %s", strerror(errno));
850             exit(EXIT_FAILURE);
851         } else if (pid == 0) {
852             close(stderr_fd[0]);
853             ret = qemu_daemon(1, 0);
854 
855             /* Temporarily redirect stderr to the parent's pipe...  */
856             old_stderr = dup(STDERR_FILENO);
857             dup2(stderr_fd[1], STDERR_FILENO);
858             if (ret < 0) {
859                 error_report("Failed to daemonize: %s", strerror(errno));
860                 exit(EXIT_FAILURE);
861             }
862 
863             /* ... close the descriptor we inherited and go on.  */
864             close(stderr_fd[1]);
865         } else {
866             bool errors = false;
867             char *buf;
868 
869             /* In the parent.  Print error messages from the child until
870              * it closes the pipe.
871              */
872             close(stderr_fd[1]);
873             buf = g_malloc(1024);
874             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
875                 errors = true;
876                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
877                 if (ret < 0) {
878                     exit(EXIT_FAILURE);
879                 }
880             }
881             if (ret < 0) {
882                 error_report("Cannot read from daemon: %s",
883                              strerror(errno));
884                 exit(EXIT_FAILURE);
885             }
886 
887             /* Usually the daemon should not print any message.
888              * Exit with zero status in that case.
889              */
890             exit(errors);
891         }
892     }
893 
894     if (device != NULL && sockpath == NULL) {
895         sockpath = g_malloc(128);
896         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
897     }
898 
899     server = qio_net_listener_new();
900     if (socket_activation == 0) {
901         saddr = nbd_build_socket_address(sockpath, bindto, port);
902         if (qio_net_listener_open_sync(server, saddr, &local_err) < 0) {
903             object_unref(OBJECT(server));
904             error_report_err(local_err);
905             exit(EXIT_FAILURE);
906         }
907     } else {
908         size_t i;
909         /* See comment in check_socket_activation above. */
910         for (i = 0; i < socket_activation; i++) {
911             QIOChannelSocket *sioc;
912             sioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD + i,
913                                              &local_err);
914             if (sioc == NULL) {
915                 object_unref(OBJECT(server));
916                 error_report("Failed to use socket activation: %s",
917                              error_get_pretty(local_err));
918                 exit(EXIT_FAILURE);
919             }
920             qio_net_listener_add(server, sioc);
921             object_unref(OBJECT(sioc));
922         }
923     }
924 
925     if (qemu_init_main_loop(&local_err)) {
926         error_report_err(local_err);
927         exit(EXIT_FAILURE);
928     }
929     bdrv_init();
930     atexit(bdrv_close_all);
931 
932     srcpath = argv[optind];
933     if (imageOpts) {
934         QemuOpts *opts;
935         if (fmt) {
936             error_report("--image-opts and -f are mutually exclusive");
937             exit(EXIT_FAILURE);
938         }
939         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
940         if (!opts) {
941             qemu_opts_reset(&file_opts);
942             exit(EXIT_FAILURE);
943         }
944         options = qemu_opts_to_qdict(opts, NULL);
945         qemu_opts_reset(&file_opts);
946         blk = blk_new_open(NULL, NULL, options, flags, &local_err);
947     } else {
948         if (fmt) {
949             options = qdict_new();
950             qdict_put_str(options, "driver", fmt);
951         }
952         blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
953     }
954 
955     if (!blk) {
956         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
957                           argv[optind]);
958         exit(EXIT_FAILURE);
959     }
960     bs = blk_bs(blk);
961 
962     blk_set_enable_write_cache(blk, !writethrough);
963 
964     if (sn_opts) {
965         ret = bdrv_snapshot_load_tmp(bs,
966                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
967                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
968                                      &local_err);
969     } else if (sn_id_or_name) {
970         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
971                                                    &local_err);
972     }
973     if (ret < 0) {
974         error_reportf_err(local_err, "Failed to load snapshot: ");
975         exit(EXIT_FAILURE);
976     }
977 
978     bs->detect_zeroes = detect_zeroes;
979     fd_size = blk_getlength(blk);
980     if (fd_size < 0) {
981         error_report("Failed to determine the image length: %s",
982                      strerror(-fd_size));
983         exit(EXIT_FAILURE);
984     }
985 
986     if (dev_offset >= fd_size) {
987         error_report("Offset (%lld) has to be smaller than the image size "
988                      "(%lld)",
989                      (long long int)dev_offset, (long long int)fd_size);
990         exit(EXIT_FAILURE);
991     }
992     fd_size -= dev_offset;
993 
994     if (partition != -1) {
995         ret = find_partition(blk, partition, &dev_offset, &fd_size);
996         if (ret < 0) {
997             error_report("Could not find partition %d: %s", partition,
998                          strerror(-ret));
999             exit(EXIT_FAILURE);
1000         }
1001     }
1002 
1003     exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed,
1004                          writethrough, NULL, &local_err);
1005     if (!exp) {
1006         error_report_err(local_err);
1007         exit(EXIT_FAILURE);
1008     }
1009     if (export_name) {
1010         nbd_export_set_name(exp, export_name);
1011         nbd_export_set_description(exp, export_description);
1012         newproto = true;
1013     } else if (export_description) {
1014         error_report("Export description requires an export name");
1015         exit(EXIT_FAILURE);
1016     }
1017 
1018     if (device) {
1019         int ret;
1020 
1021         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
1022         if (ret != 0) {
1023             error_report("Failed to create client thread: %s", strerror(ret));
1024             exit(EXIT_FAILURE);
1025         }
1026     } else {
1027         /* Shut up GCC warnings.  */
1028         memset(&client_thread, 0, sizeof(client_thread));
1029     }
1030 
1031     nbd_update_server_watch();
1032 
1033     /* now when the initialization is (almost) complete, chdir("/")
1034      * to free any busy filesystems */
1035     if (chdir("/") < 0) {
1036         error_report("Could not chdir to root directory: %s",
1037                      strerror(errno));
1038         exit(EXIT_FAILURE);
1039     }
1040 
1041     if (fork_process) {
1042         dup2(old_stderr, STDERR_FILENO);
1043         close(old_stderr);
1044     }
1045 
1046     state = RUNNING;
1047     do {
1048         main_loop_wait(false);
1049         if (state == TERMINATE) {
1050             state = TERMINATING;
1051             nbd_export_close(exp);
1052             nbd_export_put(exp);
1053             exp = NULL;
1054         }
1055     } while (state != TERMINATED);
1056 
1057     blk_unref(blk);
1058     if (sockpath) {
1059         unlink(sockpath);
1060     }
1061 
1062     qemu_opts_del(sn_opts);
1063 
1064     if (device) {
1065         void *ret;
1066         pthread_join(client_thread, &ret);
1067         exit(ret != NULL);
1068     } else {
1069         exit(EXIT_SUCCESS);
1070     }
1071 }
1072