xref: /openbmc/qemu/qemu-nbd.c (revision d9018fbbd68bf3a8338828ee3038341518c74212)
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 "  -P, --partition=NUM       only expose partition NUM\n"
104 "  -B, --bitmap=NAME         expose a persistent dirty bitmap\n"
105 "\n"
106 "General purpose options:\n"
107 "  -L, --list                list exports available from another NBD server\n"
108 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
109 "                            passwords and/or encryption keys\n"
110 "  --tls-creds=ID            use id of an earlier --object to provide TLS\n"
111 "  --tls-authz=ID            use id of an earlier --object to provide\n"
112 "                            authorization\n"
113 "  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
114 "                            specify tracing options\n"
115 "  --fork                    fork off the server process and exit the parent\n"
116 "                            once the server is running\n"
117 "  --pid-file=PATH           store the server's process ID in the given file\n"
118 #if HAVE_NBD_DEVICE
119 "\n"
120 "Kernel NBD client support:\n"
121 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
122 "  -d, --disconnect          disconnect the specified device\n"
123 #endif
124 "\n"
125 "Block device options:\n"
126 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
127 "  -r, --read-only           export read-only\n"
128 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
129 "                            file with backing_file=FILE, redirect the write to\n"
130 "                            the temporary one\n"
131 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
132 "                            load an internal snapshot inside FILE and export it\n"
133 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
134 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
135 "                            '[ID_OR_NAME]'\n"
136 "  -n, --nocache             disable host cache\n"
137 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
138 "      --aio=MODE            set AIO mode (native, io_uring or threads)\n"
139 "      --discard=MODE        set discard mode (ignore, unmap)\n"
140 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
141 "      --image-opts          treat FILE as a full set of image options\n"
142 "\n"
143 QEMU_HELP_BOTTOM "\n"
144     , name, name, NBD_DEFAULT_PORT, "DEVICE");
145 }
146 
147 static void version(const char *name)
148 {
149     printf(
150 "%s " QEMU_FULL_VERSION "\n"
151 "Written by Anthony Liguori.\n"
152 "\n"
153 QEMU_COPYRIGHT "\n"
154 "This is free software; see the source for copying conditions.  There is NO\n"
155 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
156     , name);
157 }
158 
159 struct partition_record
160 {
161     uint8_t bootable;
162     uint8_t start_head;
163     uint32_t start_cylinder;
164     uint8_t start_sector;
165     uint8_t system;
166     uint8_t end_head;
167     uint8_t end_cylinder;
168     uint8_t end_sector;
169     uint32_t start_sector_abs;
170     uint32_t nb_sectors_abs;
171 };
172 
173 static void read_partition(uint8_t *p, struct partition_record *r)
174 {
175     r->bootable = p[0];
176     r->start_head = p[1];
177     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
178     r->start_sector = p[2] & 0x3f;
179     r->system = p[4];
180     r->end_head = p[5];
181     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
182     r->end_sector = p[6] & 0x3f;
183 
184     r->start_sector_abs = ldl_le_p(p + 8);
185     r->nb_sectors_abs   = ldl_le_p(p + 12);
186 }
187 
188 static int find_partition(BlockBackend *blk, int partition,
189                           uint64_t *offset, uint64_t *size)
190 {
191     struct partition_record mbr[4];
192     uint8_t data[MBR_SIZE];
193     int i;
194     int ext_partnum = 4;
195     int ret;
196 
197     ret = blk_pread(blk, 0, data, sizeof(data));
198     if (ret < 0) {
199         error_report("error while reading: %s", strerror(-ret));
200         exit(EXIT_FAILURE);
201     }
202 
203     if (data[510] != 0x55 || data[511] != 0xaa) {
204         return -EINVAL;
205     }
206 
207     for (i = 0; i < 4; i++) {
208         read_partition(&data[446 + 16 * i], &mbr[i]);
209 
210         if (!mbr[i].system || !mbr[i].nb_sectors_abs) {
211             continue;
212         }
213 
214         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
215             struct partition_record ext[4];
216             uint8_t data1[MBR_SIZE];
217             int j;
218 
219             ret = blk_pread(blk, mbr[i].start_sector_abs * MBR_SIZE,
220                             data1, sizeof(data1));
221             if (ret < 0) {
222                 error_report("error while reading: %s", strerror(-ret));
223                 exit(EXIT_FAILURE);
224             }
225 
226             for (j = 0; j < 4; j++) {
227                 read_partition(&data1[446 + 16 * j], &ext[j]);
228                 if (!ext[j].system || !ext[j].nb_sectors_abs) {
229                     continue;
230                 }
231 
232                 if ((ext_partnum + j + 1) == partition) {
233                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
234                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
235                     return 0;
236                 }
237             }
238             ext_partnum += 4;
239         } else if ((i + 1) == partition) {
240             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
241             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
242             return 0;
243         }
244     }
245 
246     return -ENOENT;
247 }
248 
249 static void termsig_handler(int signum)
250 {
251     atomic_cmpxchg(&state, RUNNING, TERMINATE);
252     qemu_notify_event();
253 }
254 
255 
256 static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
257                                 const char *hostname)
258 {
259     int ret = EXIT_FAILURE;
260     int rc;
261     Error *err = NULL;
262     QIOChannelSocket *sioc;
263     NBDExportInfo *list;
264     int i, j;
265 
266     sioc = qio_channel_socket_new();
267     if (qio_channel_socket_connect_sync(sioc, saddr, &err) < 0) {
268         error_report_err(err);
269         return EXIT_FAILURE;
270     }
271     rc = nbd_receive_export_list(QIO_CHANNEL(sioc), tls, hostname, &list,
272                                  &err);
273     if (rc < 0) {
274         if (err) {
275             error_report_err(err);
276         }
277         goto out;
278     }
279     printf("exports available: %d\n", rc);
280     for (i = 0; i < rc; i++) {
281         printf(" export: '%s'\n", list[i].name);
282         if (list[i].description && *list[i].description) {
283             printf("  description: %s\n", list[i].description);
284         }
285         if (list[i].flags & NBD_FLAG_HAS_FLAGS) {
286             static const char *const flag_names[] = {
287                 [NBD_FLAG_READ_ONLY_BIT]            = "readonly",
288                 [NBD_FLAG_SEND_FLUSH_BIT]           = "flush",
289                 [NBD_FLAG_SEND_FUA_BIT]             = "fua",
290                 [NBD_FLAG_ROTATIONAL_BIT]           = "rotational",
291                 [NBD_FLAG_SEND_TRIM_BIT]            = "trim",
292                 [NBD_FLAG_SEND_WRITE_ZEROES_BIT]    = "zeroes",
293                 [NBD_FLAG_SEND_DF_BIT]              = "df",
294                 [NBD_FLAG_CAN_MULTI_CONN_BIT]       = "multi",
295                 [NBD_FLAG_SEND_RESIZE_BIT]          = "resize",
296                 [NBD_FLAG_SEND_CACHE_BIT]           = "cache",
297                 [NBD_FLAG_SEND_FAST_ZERO_BIT]       = "fast-zero",
298             };
299 
300             printf("  size:  %" PRIu64 "\n", list[i].size);
301             printf("  flags: 0x%x (", list[i].flags);
302             for (size_t bit = 0; bit < ARRAY_SIZE(flag_names); bit++) {
303                 if (flag_names[bit] && (list[i].flags & (1 << bit))) {
304                     printf(" %s", flag_names[bit]);
305                 }
306             }
307             printf(" )\n");
308         }
309         if (list[i].min_block) {
310             printf("  min block: %u\n", list[i].min_block);
311             printf("  opt block: %u\n", list[i].opt_block);
312             printf("  max block: %u\n", list[i].max_block);
313         }
314         if (list[i].n_contexts) {
315             printf("  available meta contexts: %d\n", list[i].n_contexts);
316             for (j = 0; j < list[i].n_contexts; j++) {
317                 printf("   %s\n", list[i].contexts[j]);
318             }
319         }
320     }
321     nbd_free_export_list(list, rc);
322 
323     ret = EXIT_SUCCESS;
324  out:
325     object_unref(OBJECT(sioc));
326     return ret;
327 }
328 
329 
330 #if HAVE_NBD_DEVICE
331 static void *show_parts(void *arg)
332 {
333     char *device = arg;
334     int nbd;
335 
336     /* linux just needs an open() to trigger
337      * the partition table update
338      * but remember to load the module with max_part != 0 :
339      *     modprobe nbd max_part=63
340      */
341     nbd = open(device, O_RDWR);
342     if (nbd >= 0) {
343         close(nbd);
344     }
345     return NULL;
346 }
347 
348 static void *nbd_client_thread(void *arg)
349 {
350     char *device = arg;
351     NBDExportInfo info = { .request_sizes = false, .name = g_strdup("") };
352     QIOChannelSocket *sioc;
353     int fd;
354     int ret;
355     pthread_t show_parts_thread;
356     Error *local_error = NULL;
357 
358     sioc = qio_channel_socket_new();
359     if (qio_channel_socket_connect_sync(sioc,
360                                         saddr,
361                                         &local_error) < 0) {
362         error_report_err(local_error);
363         goto out;
364     }
365 
366     ret = nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc),
367                                 NULL, NULL, NULL, &info, &local_error);
368     if (ret < 0) {
369         if (local_error) {
370             error_report_err(local_error);
371         }
372         goto out_socket;
373     }
374 
375     fd = open(device, O_RDWR);
376     if (fd < 0) {
377         /* Linux-only, we can use %m in printf.  */
378         error_report("Failed to open %s: %m", device);
379         goto out_socket;
380     }
381 
382     ret = nbd_init(fd, sioc, &info, &local_error);
383     if (ret < 0) {
384         error_report_err(local_error);
385         goto out_fd;
386     }
387 
388     /* update partition table */
389     pthread_create(&show_parts_thread, NULL, show_parts, device);
390 
391     if (verbose) {
392         fprintf(stderr, "NBD device %s is now connected to %s\n",
393                 device, srcpath);
394     } else {
395         /* Close stderr so that the qemu-nbd process exits.  */
396         dup2(STDOUT_FILENO, STDERR_FILENO);
397     }
398 
399     ret = nbd_client(fd);
400     if (ret) {
401         goto out_fd;
402     }
403     close(fd);
404     object_unref(OBJECT(sioc));
405     g_free(info.name);
406     kill(getpid(), SIGTERM);
407     return (void *) EXIT_SUCCESS;
408 
409 out_fd:
410     close(fd);
411 out_socket:
412     object_unref(OBJECT(sioc));
413 out:
414     g_free(info.name);
415     kill(getpid(), SIGTERM);
416     return (void *) EXIT_FAILURE;
417 }
418 #endif /* HAVE_NBD_DEVICE */
419 
420 static int nbd_can_accept(void)
421 {
422     return state == RUNNING && nb_fds < shared;
423 }
424 
425 static void nbd_export_closed(NBDExport *export)
426 {
427     assert(state == TERMINATING);
428     state = TERMINATED;
429 }
430 
431 static void nbd_update_server_watch(void);
432 
433 static void nbd_client_closed(NBDClient *client, bool negotiated)
434 {
435     nb_fds--;
436     if (negotiated && nb_fds == 0 && !persistent && state == RUNNING) {
437         state = TERMINATE;
438     }
439     nbd_update_server_watch();
440     nbd_client_put(client);
441 }
442 
443 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
444                        gpointer opaque)
445 {
446     if (state >= TERMINATE) {
447         return;
448     }
449 
450     nb_fds++;
451     nbd_update_server_watch();
452     nbd_client_new(cioc, tlscreds, tlsauthz, nbd_client_closed);
453 }
454 
455 static void nbd_update_server_watch(void)
456 {
457     if (nbd_can_accept()) {
458         qio_net_listener_set_client_func(server, nbd_accept, NULL, NULL);
459     } else {
460         qio_net_listener_set_client_func(server, NULL, NULL, NULL);
461     }
462 }
463 
464 
465 static SocketAddress *nbd_build_socket_address(const char *sockpath,
466                                                const char *bindto,
467                                                const char *port)
468 {
469     SocketAddress *saddr;
470 
471     saddr = g_new0(SocketAddress, 1);
472     if (sockpath) {
473         saddr->type = SOCKET_ADDRESS_TYPE_UNIX;
474         saddr->u.q_unix.path = g_strdup(sockpath);
475     } else {
476         InetSocketAddress *inet;
477         saddr->type = SOCKET_ADDRESS_TYPE_INET;
478         inet = &saddr->u.inet;
479         inet->host = g_strdup(bindto);
480         if (port) {
481             inet->port = g_strdup(port);
482         } else  {
483             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
484         }
485     }
486 
487     return saddr;
488 }
489 
490 
491 static QemuOptsList file_opts = {
492     .name = "file",
493     .implied_opt_name = "file",
494     .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
495     .desc = {
496         /* no elements => accept any params */
497         { /* end of list */ }
498     },
499 };
500 
501 static QemuOptsList qemu_object_opts = {
502     .name = "object",
503     .implied_opt_name = "qom-type",
504     .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
505     .desc = {
506         { }
507     },
508 };
509 
510 static bool qemu_nbd_object_print_help(const char *type, QemuOpts *opts)
511 {
512     if (user_creatable_print_help(type, opts)) {
513         exit(0);
514     }
515     return true;
516 }
517 
518 
519 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, bool list,
520                                           Error **errp)
521 {
522     Object *obj;
523     QCryptoTLSCreds *creds;
524 
525     obj = object_resolve_path_component(
526         object_get_objects_root(), id);
527     if (!obj) {
528         error_setg(errp, "No TLS credentials with id '%s'",
529                    id);
530         return NULL;
531     }
532     creds = (QCryptoTLSCreds *)
533         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
534     if (!creds) {
535         error_setg(errp, "Object with id '%s' is not TLS credentials",
536                    id);
537         return NULL;
538     }
539 
540     if (list) {
541         if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
542             error_setg(errp,
543                        "Expecting TLS credentials with a client endpoint");
544             return NULL;
545         }
546     } else {
547         if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
548             error_setg(errp,
549                        "Expecting TLS credentials with a server endpoint");
550             return NULL;
551         }
552     }
553     object_ref(obj);
554     return creds;
555 }
556 
557 static void setup_address_and_port(const char **address, const char **port)
558 {
559     if (*address == NULL) {
560         *address = "0.0.0.0";
561     }
562 
563     if (*port == NULL) {
564         *port = stringify(NBD_DEFAULT_PORT);
565     }
566 }
567 
568 /*
569  * Check socket parameters compatibility when socket activation is used.
570  */
571 static const char *socket_activation_validate_opts(const char *device,
572                                                    const char *sockpath,
573                                                    const char *address,
574                                                    const char *port,
575                                                    bool list)
576 {
577     if (device != NULL) {
578         return "NBD device can't be set when using socket activation";
579     }
580 
581     if (sockpath != NULL) {
582         return "Unix socket can't be set when using socket activation";
583     }
584 
585     if (address != NULL) {
586         return "The interface can't be set when using socket activation";
587     }
588 
589     if (port != NULL) {
590         return "TCP port number can't be set when using socket activation";
591     }
592 
593     if (list) {
594         return "List mode is incompatible with socket activation";
595     }
596 
597     return NULL;
598 }
599 
600 static void qemu_nbd_shutdown(void)
601 {
602     job_cancel_sync_all();
603     bdrv_close_all();
604 }
605 
606 int main(int argc, char **argv)
607 {
608     BlockBackend *blk;
609     BlockDriverState *bs;
610     uint64_t dev_offset = 0;
611     bool readonly = false;
612     bool disconnect = false;
613     const char *bindto = NULL;
614     const char *port = NULL;
615     char *sockpath = NULL;
616     char *device = NULL;
617     int64_t fd_size;
618     QemuOpts *sn_opts = NULL;
619     const char *sn_id_or_name = NULL;
620     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:B:L";
621     struct option lopt[] = {
622         { "help", no_argument, NULL, 'h' },
623         { "version", no_argument, NULL, 'V' },
624         { "bind", required_argument, NULL, 'b' },
625         { "port", required_argument, NULL, 'p' },
626         { "socket", required_argument, NULL, 'k' },
627         { "offset", required_argument, NULL, 'o' },
628         { "read-only", no_argument, NULL, 'r' },
629         { "partition", required_argument, NULL, 'P' },
630         { "bitmap", required_argument, NULL, 'B' },
631         { "connect", required_argument, NULL, 'c' },
632         { "disconnect", no_argument, NULL, 'd' },
633         { "list", no_argument, NULL, 'L' },
634         { "snapshot", no_argument, NULL, 's' },
635         { "load-snapshot", required_argument, NULL, 'l' },
636         { "nocache", no_argument, NULL, 'n' },
637         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
638         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
639         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
640         { "detect-zeroes", required_argument, NULL,
641           QEMU_NBD_OPT_DETECT_ZEROES },
642         { "shared", required_argument, NULL, 'e' },
643         { "format", required_argument, NULL, 'f' },
644         { "persistent", no_argument, NULL, 't' },
645         { "verbose", no_argument, NULL, 'v' },
646         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
647         { "export-name", required_argument, NULL, 'x' },
648         { "description", required_argument, NULL, 'D' },
649         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
650         { "tls-authz", required_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
651         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
652         { "trace", required_argument, NULL, 'T' },
653         { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
654         { "pid-file", required_argument, NULL, QEMU_NBD_OPT_PID_FILE },
655         { NULL, 0, NULL, 0 }
656     };
657     int ch;
658     int opt_ind = 0;
659     int flags = BDRV_O_RDWR;
660     int partition = 0;
661     int ret = 0;
662     bool seen_cache = false;
663     bool seen_discard = false;
664     bool seen_aio = false;
665     pthread_t client_thread;
666     const char *fmt = NULL;
667     Error *local_err = NULL;
668     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
669     QDict *options = NULL;
670     const char *export_name = NULL; /* defaults to "" later for server mode */
671     const char *export_description = NULL;
672     const char *bitmap = NULL;
673     const char *tlscredsid = NULL;
674     bool imageOpts = false;
675     bool writethrough = true;
676     char *trace_file = NULL;
677     bool fork_process = false;
678     bool list = false;
679     int old_stderr = -1;
680     unsigned socket_activation;
681     const char *pid_file_name = NULL;
682 
683     /* The client thread uses SIGTERM to interrupt the server.  A signal
684      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
685      */
686     struct sigaction sa_sigterm;
687     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
688     sa_sigterm.sa_handler = termsig_handler;
689     sigaction(SIGTERM, &sa_sigterm, NULL);
690 
691 #ifdef CONFIG_POSIX
692     signal(SIGPIPE, SIG_IGN);
693 #endif
694 
695     error_init(argv[0]);
696     module_call_init(MODULE_INIT_TRACE);
697     qcrypto_init(&error_fatal);
698 
699     module_call_init(MODULE_INIT_QOM);
700     qemu_add_opts(&qemu_object_opts);
701     qemu_add_opts(&qemu_trace_opts);
702     qemu_init_exec_dir(argv[0]);
703 
704     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
705         switch (ch) {
706         case 's':
707             flags |= BDRV_O_SNAPSHOT;
708             break;
709         case 'n':
710             optarg = (char *) "none";
711             /* fallthrough */
712         case QEMU_NBD_OPT_CACHE:
713             if (seen_cache) {
714                 error_report("-n and --cache can only be specified once");
715                 exit(EXIT_FAILURE);
716             }
717             seen_cache = true;
718             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
719                 error_report("Invalid cache mode `%s'", optarg);
720                 exit(EXIT_FAILURE);
721             }
722             break;
723         case QEMU_NBD_OPT_AIO:
724             if (seen_aio) {
725                 error_report("--aio can only be specified once");
726                 exit(EXIT_FAILURE);
727             }
728             seen_aio = true;
729             if (bdrv_parse_aio(optarg, &flags) < 0) {
730                 error_report("Invalid aio mode '%s'", optarg);
731                 exit(EXIT_FAILURE);
732             }
733             break;
734         case QEMU_NBD_OPT_DISCARD:
735             if (seen_discard) {
736                 error_report("--discard can only be specified once");
737                 exit(EXIT_FAILURE);
738             }
739             seen_discard = true;
740             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
741                 error_report("Invalid discard mode `%s'", optarg);
742                 exit(EXIT_FAILURE);
743             }
744             break;
745         case QEMU_NBD_OPT_DETECT_ZEROES:
746             detect_zeroes =
747                 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup,
748                                 optarg,
749                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
750                                 &local_err);
751             if (local_err) {
752                 error_reportf_err(local_err,
753                                   "Failed to parse detect_zeroes mode: ");
754                 exit(EXIT_FAILURE);
755             }
756             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
757                 !(flags & BDRV_O_UNMAP)) {
758                 error_report("setting detect-zeroes to unmap is not allowed "
759                              "without setting discard operation to unmap");
760                 exit(EXIT_FAILURE);
761             }
762             break;
763         case 'b':
764             bindto = optarg;
765             break;
766         case 'p':
767             port = optarg;
768             break;
769         case 'o':
770             if (qemu_strtou64(optarg, NULL, 0, &dev_offset) < 0) {
771                 error_report("Invalid offset '%s'", optarg);
772                 exit(EXIT_FAILURE);
773             }
774             break;
775         case 'l':
776             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
777                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
778                                                   optarg, false);
779                 if (!sn_opts) {
780                     error_report("Failed in parsing snapshot param `%s'",
781                                  optarg);
782                     exit(EXIT_FAILURE);
783                 }
784             } else {
785                 sn_id_or_name = optarg;
786             }
787             /* fall through */
788         case 'r':
789             readonly = true;
790             flags &= ~BDRV_O_RDWR;
791             break;
792         case 'P':
793             warn_report("The '-P' option is deprecated; use --image-opts with "
794                         "a raw device wrapper for subset exports instead");
795             if (qemu_strtoi(optarg, NULL, 0, &partition) < 0 ||
796                 partition < 1 || partition > 8) {
797                 error_report("Invalid partition '%s'", optarg);
798                 exit(EXIT_FAILURE);
799             }
800             break;
801         case 'B':
802             bitmap = optarg;
803             break;
804         case 'k':
805             sockpath = optarg;
806             if (sockpath[0] != '/') {
807                 error_report("socket path must be absolute");
808                 exit(EXIT_FAILURE);
809             }
810             break;
811         case 'd':
812             disconnect = true;
813             break;
814         case 'c':
815             device = optarg;
816             break;
817         case 'e':
818             if (qemu_strtoi(optarg, NULL, 0, &shared) < 0 ||
819                 shared < 1) {
820                 error_report("Invalid shared device number '%s'", optarg);
821                 exit(EXIT_FAILURE);
822             }
823             break;
824         case 'f':
825             fmt = optarg;
826             break;
827         case 't':
828             persistent = 1;
829             break;
830         case 'x':
831             export_name = optarg;
832             if (strlen(export_name) > NBD_MAX_STRING_SIZE) {
833                 error_report("export name '%s' too long", export_name);
834                 exit(EXIT_FAILURE);
835             }
836             break;
837         case 'D':
838             export_description = optarg;
839             if (strlen(export_description) > NBD_MAX_STRING_SIZE) {
840                 error_report("export description '%s' too long",
841                              export_description);
842                 exit(EXIT_FAILURE);
843             }
844             break;
845         case 'v':
846             verbose = 1;
847             break;
848         case 'V':
849             version(argv[0]);
850             exit(0);
851             break;
852         case 'h':
853             usage(argv[0]);
854             exit(0);
855             break;
856         case '?':
857             error_report("Try `%s --help' for more information.", argv[0]);
858             exit(EXIT_FAILURE);
859         case QEMU_NBD_OPT_OBJECT: {
860             QemuOpts *opts;
861             opts = qemu_opts_parse_noisily(&qemu_object_opts,
862                                            optarg, true);
863             if (!opts) {
864                 exit(EXIT_FAILURE);
865             }
866         }   break;
867         case QEMU_NBD_OPT_TLSCREDS:
868             tlscredsid = optarg;
869             break;
870         case QEMU_NBD_OPT_IMAGE_OPTS:
871             imageOpts = true;
872             break;
873         case 'T':
874             g_free(trace_file);
875             trace_file = trace_opt_parse(optarg);
876             break;
877         case QEMU_NBD_OPT_TLSAUTHZ:
878             tlsauthz = optarg;
879             break;
880         case QEMU_NBD_OPT_FORK:
881             fork_process = true;
882             break;
883         case 'L':
884             list = true;
885             break;
886         case QEMU_NBD_OPT_PID_FILE:
887             pid_file_name = optarg;
888             break;
889         }
890     }
891 
892     if (list) {
893         if (argc != optind) {
894             error_report("List mode is incompatible with a file name");
895             exit(EXIT_FAILURE);
896         }
897         if (export_name || export_description || dev_offset || partition ||
898             device || disconnect || fmt || sn_id_or_name || bitmap ||
899             seen_aio || seen_discard || seen_cache) {
900             error_report("List mode is incompatible with per-device settings");
901             exit(EXIT_FAILURE);
902         }
903         if (fork_process) {
904             error_report("List mode is incompatible with forking");
905             exit(EXIT_FAILURE);
906         }
907     } else if ((argc - optind) != 1) {
908         error_report("Invalid number of arguments");
909         error_printf("Try `%s --help' for more information.\n", argv[0]);
910         exit(EXIT_FAILURE);
911     } else if (!export_name) {
912         export_name = "";
913     }
914 
915     qemu_opts_foreach(&qemu_object_opts,
916                       user_creatable_add_opts_foreach,
917                       qemu_nbd_object_print_help, &error_fatal);
918 
919     if (!trace_init_backends()) {
920         exit(1);
921     }
922     trace_init_file(trace_file);
923     qemu_set_log(LOG_TRACE);
924 
925     socket_activation = check_socket_activation();
926     if (socket_activation == 0) {
927         setup_address_and_port(&bindto, &port);
928     } else {
929         /* Using socket activation - check user didn't use -p etc. */
930         const char *err_msg = socket_activation_validate_opts(device, sockpath,
931                                                               bindto, port,
932                                                               list);
933         if (err_msg != NULL) {
934             error_report("%s", err_msg);
935             exit(EXIT_FAILURE);
936         }
937 
938         /* qemu-nbd can only listen on a single socket.  */
939         if (socket_activation > 1) {
940             error_report("qemu-nbd does not support socket activation with %s > 1",
941                          "LISTEN_FDS");
942             exit(EXIT_FAILURE);
943         }
944     }
945 
946     if (tlscredsid) {
947         if (sockpath) {
948             error_report("TLS is only supported with IPv4/IPv6");
949             exit(EXIT_FAILURE);
950         }
951         if (device) {
952             error_report("TLS is not supported with a host device");
953             exit(EXIT_FAILURE);
954         }
955         if (tlsauthz && list) {
956             error_report("TLS authorization is incompatible with export list");
957             exit(EXIT_FAILURE);
958         }
959         tlscreds = nbd_get_tls_creds(tlscredsid, list, &local_err);
960         if (local_err) {
961             error_report("Failed to get TLS creds %s",
962                          error_get_pretty(local_err));
963             exit(EXIT_FAILURE);
964         }
965     } else {
966         if (tlsauthz) {
967             error_report("--tls-authz is not permitted without --tls-creds");
968             exit(EXIT_FAILURE);
969         }
970     }
971 
972     if (list) {
973         saddr = nbd_build_socket_address(sockpath, bindto, port);
974         return qemu_nbd_client_list(saddr, tlscreds, bindto);
975     }
976 
977 #if !HAVE_NBD_DEVICE
978     if (disconnect || device) {
979         error_report("Kernel /dev/nbdN support not available");
980         exit(EXIT_FAILURE);
981     }
982 #else /* HAVE_NBD_DEVICE */
983     if (disconnect) {
984         int nbdfd = open(argv[optind], O_RDWR);
985         if (nbdfd < 0) {
986             error_report("Cannot open %s: %s", argv[optind],
987                          strerror(errno));
988             exit(EXIT_FAILURE);
989         }
990         nbd_disconnect(nbdfd);
991 
992         close(nbdfd);
993 
994         printf("%s disconnected\n", argv[optind]);
995 
996         return 0;
997     }
998 #endif
999 
1000     if ((device && !verbose) || fork_process) {
1001         int stderr_fd[2];
1002         pid_t pid;
1003         int ret;
1004 
1005         if (qemu_pipe(stderr_fd) < 0) {
1006             error_report("Error setting up communication pipe: %s",
1007                          strerror(errno));
1008             exit(EXIT_FAILURE);
1009         }
1010 
1011         /* Now daemonize, but keep a communication channel open to
1012          * print errors and exit with the proper status code.
1013          */
1014         pid = fork();
1015         if (pid < 0) {
1016             error_report("Failed to fork: %s", strerror(errno));
1017             exit(EXIT_FAILURE);
1018         } else if (pid == 0) {
1019             close(stderr_fd[0]);
1020 
1021             old_stderr = dup(STDERR_FILENO);
1022             ret = qemu_daemon(1, 0);
1023 
1024             /* Temporarily redirect stderr to the parent's pipe...  */
1025             dup2(stderr_fd[1], STDERR_FILENO);
1026             if (ret < 0) {
1027                 error_report("Failed to daemonize: %s", strerror(errno));
1028                 exit(EXIT_FAILURE);
1029             }
1030 
1031             /* ... close the descriptor we inherited and go on.  */
1032             close(stderr_fd[1]);
1033         } else {
1034             bool errors = false;
1035             char *buf;
1036 
1037             /* In the parent.  Print error messages from the child until
1038              * it closes the pipe.
1039              */
1040             close(stderr_fd[1]);
1041             buf = g_malloc(1024);
1042             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
1043                 errors = true;
1044                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
1045                 if (ret < 0) {
1046                     exit(EXIT_FAILURE);
1047                 }
1048             }
1049             if (ret < 0) {
1050                 error_report("Cannot read from daemon: %s",
1051                              strerror(errno));
1052                 exit(EXIT_FAILURE);
1053             }
1054 
1055             /* Usually the daemon should not print any message.
1056              * Exit with zero status in that case.
1057              */
1058             exit(errors);
1059         }
1060     }
1061 
1062     if (device != NULL && sockpath == NULL) {
1063         sockpath = g_malloc(128);
1064         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
1065     }
1066 
1067     server = qio_net_listener_new();
1068     if (socket_activation == 0) {
1069         saddr = nbd_build_socket_address(sockpath, bindto, port);
1070         if (qio_net_listener_open_sync(server, saddr, 1, &local_err) < 0) {
1071             object_unref(OBJECT(server));
1072             error_report_err(local_err);
1073             exit(EXIT_FAILURE);
1074         }
1075     } else {
1076         size_t i;
1077         /* See comment in check_socket_activation above. */
1078         for (i = 0; i < socket_activation; i++) {
1079             QIOChannelSocket *sioc;
1080             sioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD + i,
1081                                              &local_err);
1082             if (sioc == NULL) {
1083                 object_unref(OBJECT(server));
1084                 error_report("Failed to use socket activation: %s",
1085                              error_get_pretty(local_err));
1086                 exit(EXIT_FAILURE);
1087             }
1088             qio_net_listener_add(server, sioc);
1089             object_unref(OBJECT(sioc));
1090         }
1091     }
1092 
1093     if (qemu_init_main_loop(&local_err)) {
1094         error_report_err(local_err);
1095         exit(EXIT_FAILURE);
1096     }
1097     bdrv_init();
1098     atexit(qemu_nbd_shutdown);
1099 
1100     srcpath = argv[optind];
1101     if (imageOpts) {
1102         QemuOpts *opts;
1103         if (fmt) {
1104             error_report("--image-opts and -f are mutually exclusive");
1105             exit(EXIT_FAILURE);
1106         }
1107         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
1108         if (!opts) {
1109             qemu_opts_reset(&file_opts);
1110             exit(EXIT_FAILURE);
1111         }
1112         options = qemu_opts_to_qdict(opts, NULL);
1113         qemu_opts_reset(&file_opts);
1114         blk = blk_new_open(NULL, NULL, options, flags, &local_err);
1115     } else {
1116         if (fmt) {
1117             options = qdict_new();
1118             qdict_put_str(options, "driver", fmt);
1119         }
1120         blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
1121     }
1122 
1123     if (!blk) {
1124         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
1125                           argv[optind]);
1126         exit(EXIT_FAILURE);
1127     }
1128     bs = blk_bs(blk);
1129 
1130     blk_set_enable_write_cache(blk, !writethrough);
1131 
1132     if (sn_opts) {
1133         ret = bdrv_snapshot_load_tmp(bs,
1134                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
1135                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
1136                                      &local_err);
1137     } else if (sn_id_or_name) {
1138         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
1139                                                    &local_err);
1140     }
1141     if (ret < 0) {
1142         error_reportf_err(local_err, "Failed to load snapshot: ");
1143         exit(EXIT_FAILURE);
1144     }
1145 
1146     bs->detect_zeroes = detect_zeroes;
1147     fd_size = blk_getlength(blk);
1148     if (fd_size < 0) {
1149         error_report("Failed to determine the image length: %s",
1150                      strerror(-fd_size));
1151         exit(EXIT_FAILURE);
1152     }
1153 
1154     if (dev_offset >= fd_size) {
1155         error_report("Offset (%" PRIu64 ") has to be smaller than the image "
1156                      "size (%" PRId64 ")", dev_offset, fd_size);
1157         exit(EXIT_FAILURE);
1158     }
1159     fd_size -= dev_offset;
1160 
1161     if (partition) {
1162         uint64_t limit;
1163 
1164         if (dev_offset) {
1165             error_report("Cannot request partition and offset together");
1166             exit(EXIT_FAILURE);
1167         }
1168         ret = find_partition(blk, partition, &dev_offset, &limit);
1169         if (ret < 0) {
1170             error_report("Could not find partition %d: %s", partition,
1171                          strerror(-ret));
1172             exit(EXIT_FAILURE);
1173         }
1174         /*
1175          * MBR partition limits are (32-bit << 9); this assert lets
1176          * the compiler know that we can't overflow 64 bits.
1177          */
1178         assert(dev_offset + limit >= dev_offset);
1179         if (dev_offset + limit > fd_size) {
1180             error_report("Discovered partition %d at offset %" PRIu64
1181                          " size %" PRIu64 ", but size exceeds file length %"
1182                          PRId64, partition, dev_offset, limit, fd_size);
1183             exit(EXIT_FAILURE);
1184         }
1185         fd_size = limit;
1186     }
1187 
1188     export = nbd_export_new(bs, dev_offset, fd_size, export_name,
1189                             export_description, bitmap, readonly, shared > 1,
1190                             nbd_export_closed, writethrough, NULL,
1191                             &error_fatal);
1192 
1193     if (device) {
1194 #if HAVE_NBD_DEVICE
1195         int ret;
1196 
1197         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
1198         if (ret != 0) {
1199             error_report("Failed to create client thread: %s", strerror(ret));
1200             exit(EXIT_FAILURE);
1201         }
1202 #endif
1203     } else {
1204         /* Shut up GCC warnings.  */
1205         memset(&client_thread, 0, sizeof(client_thread));
1206     }
1207 
1208     nbd_update_server_watch();
1209 
1210     if (pid_file_name) {
1211         qemu_write_pidfile(pid_file_name, &error_fatal);
1212     }
1213 
1214     /* now when the initialization is (almost) complete, chdir("/")
1215      * to free any busy filesystems */
1216     if (chdir("/") < 0) {
1217         error_report("Could not chdir to root directory: %s",
1218                      strerror(errno));
1219         exit(EXIT_FAILURE);
1220     }
1221 
1222     if (fork_process) {
1223         dup2(old_stderr, STDERR_FILENO);
1224         close(old_stderr);
1225     }
1226 
1227     state = RUNNING;
1228     do {
1229         main_loop_wait(false);
1230         if (state == TERMINATE) {
1231             state = TERMINATING;
1232             nbd_export_close(export);
1233             nbd_export_put(export);
1234             export = NULL;
1235         }
1236     } while (state != TERMINATED);
1237 
1238     blk_unref(blk);
1239     if (sockpath) {
1240         unlink(sockpath);
1241     }
1242 
1243     qemu_opts_del(sn_opts);
1244 
1245     if (device) {
1246         void *ret;
1247         pthread_join(client_thread, &ret);
1248         exit(ret != NULL);
1249     } else {
1250         exit(EXIT_SUCCESS);
1251     }
1252 }
1253