xref: /openbmc/qemu/qemu-nbd.c (revision 0b84b662)
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 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 
511 
512 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, bool list,
513                                           Error **errp)
514 {
515     Object *obj;
516     QCryptoTLSCreds *creds;
517 
518     obj = object_resolve_path_component(
519         object_get_objects_root(), id);
520     if (!obj) {
521         error_setg(errp, "No TLS credentials with id '%s'",
522                    id);
523         return NULL;
524     }
525     creds = (QCryptoTLSCreds *)
526         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
527     if (!creds) {
528         error_setg(errp, "Object with id '%s' is not TLS credentials",
529                    id);
530         return NULL;
531     }
532 
533     if (list) {
534         if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
535             error_setg(errp,
536                        "Expecting TLS credentials with a client endpoint");
537             return NULL;
538         }
539     } else {
540         if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
541             error_setg(errp,
542                        "Expecting TLS credentials with a server endpoint");
543             return NULL;
544         }
545     }
546     object_ref(obj);
547     return creds;
548 }
549 
550 static void setup_address_and_port(const char **address, const char **port)
551 {
552     if (*address == NULL) {
553         *address = "0.0.0.0";
554     }
555 
556     if (*port == NULL) {
557         *port = stringify(NBD_DEFAULT_PORT);
558     }
559 }
560 
561 /*
562  * Check socket parameters compatibility when socket activation is used.
563  */
564 static const char *socket_activation_validate_opts(const char *device,
565                                                    const char *sockpath,
566                                                    const char *address,
567                                                    const char *port,
568                                                    bool list)
569 {
570     if (device != NULL) {
571         return "NBD device can't be set when using socket activation";
572     }
573 
574     if (sockpath != NULL) {
575         return "Unix socket can't be set when using socket activation";
576     }
577 
578     if (address != NULL) {
579         return "The interface can't be set when using socket activation";
580     }
581 
582     if (port != NULL) {
583         return "TCP port number can't be set when using socket activation";
584     }
585 
586     if (list) {
587         return "List mode is incompatible with socket activation";
588     }
589 
590     return NULL;
591 }
592 
593 static void qemu_nbd_shutdown(void)
594 {
595     job_cancel_sync_all();
596     bdrv_close_all();
597 }
598 
599 int main(int argc, char **argv)
600 {
601     BlockBackend *blk;
602     BlockDriverState *bs;
603     uint64_t dev_offset = 0;
604     bool readonly = false;
605     bool disconnect = false;
606     const char *bindto = NULL;
607     const char *port = NULL;
608     char *sockpath = NULL;
609     char *device = NULL;
610     int64_t fd_size;
611     QemuOpts *sn_opts = NULL;
612     const char *sn_id_or_name = NULL;
613     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:B:L";
614     struct option lopt[] = {
615         { "help", no_argument, NULL, 'h' },
616         { "version", no_argument, NULL, 'V' },
617         { "bind", required_argument, NULL, 'b' },
618         { "port", required_argument, NULL, 'p' },
619         { "socket", required_argument, NULL, 'k' },
620         { "offset", required_argument, NULL, 'o' },
621         { "read-only", no_argument, NULL, 'r' },
622         { "partition", required_argument, NULL, 'P' },
623         { "bitmap", required_argument, NULL, 'B' },
624         { "connect", required_argument, NULL, 'c' },
625         { "disconnect", no_argument, NULL, 'd' },
626         { "list", no_argument, NULL, 'L' },
627         { "snapshot", no_argument, NULL, 's' },
628         { "load-snapshot", required_argument, NULL, 'l' },
629         { "nocache", no_argument, NULL, 'n' },
630         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
631         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
632         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
633         { "detect-zeroes", required_argument, NULL,
634           QEMU_NBD_OPT_DETECT_ZEROES },
635         { "shared", required_argument, NULL, 'e' },
636         { "format", required_argument, NULL, 'f' },
637         { "persistent", no_argument, NULL, 't' },
638         { "verbose", no_argument, NULL, 'v' },
639         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
640         { "export-name", required_argument, NULL, 'x' },
641         { "description", required_argument, NULL, 'D' },
642         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
643         { "tls-authz", required_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
644         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
645         { "trace", required_argument, NULL, 'T' },
646         { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
647         { "pid-file", required_argument, NULL, QEMU_NBD_OPT_PID_FILE },
648         { NULL, 0, NULL, 0 }
649     };
650     int ch;
651     int opt_ind = 0;
652     int flags = BDRV_O_RDWR;
653     int partition = 0;
654     int ret = 0;
655     bool seen_cache = false;
656     bool seen_discard = false;
657     bool seen_aio = false;
658     pthread_t client_thread;
659     const char *fmt = NULL;
660     Error *local_err = NULL;
661     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
662     QDict *options = NULL;
663     const char *export_name = NULL; /* defaults to "" later for server mode */
664     const char *export_description = NULL;
665     const char *bitmap = NULL;
666     const char *tlscredsid = NULL;
667     bool imageOpts = false;
668     bool writethrough = true;
669     char *trace_file = NULL;
670     bool fork_process = false;
671     bool list = false;
672     int old_stderr = -1;
673     unsigned socket_activation;
674     const char *pid_file_name = NULL;
675 
676     /* The client thread uses SIGTERM to interrupt the server.  A signal
677      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
678      */
679     struct sigaction sa_sigterm;
680     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
681     sa_sigterm.sa_handler = termsig_handler;
682     sigaction(SIGTERM, &sa_sigterm, NULL);
683 
684 #ifdef CONFIG_POSIX
685     signal(SIGPIPE, SIG_IGN);
686 #endif
687 
688     error_init(argv[0]);
689     module_call_init(MODULE_INIT_TRACE);
690     qcrypto_init(&error_fatal);
691 
692     module_call_init(MODULE_INIT_QOM);
693     qemu_add_opts(&qemu_object_opts);
694     qemu_add_opts(&qemu_trace_opts);
695     qemu_init_exec_dir(argv[0]);
696 
697     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
698         switch (ch) {
699         case 's':
700             flags |= BDRV_O_SNAPSHOT;
701             break;
702         case 'n':
703             optarg = (char *) "none";
704             /* fallthrough */
705         case QEMU_NBD_OPT_CACHE:
706             if (seen_cache) {
707                 error_report("-n and --cache can only be specified once");
708                 exit(EXIT_FAILURE);
709             }
710             seen_cache = true;
711             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
712                 error_report("Invalid cache mode `%s'", optarg);
713                 exit(EXIT_FAILURE);
714             }
715             break;
716         case QEMU_NBD_OPT_AIO:
717             if (seen_aio) {
718                 error_report("--aio can only be specified once");
719                 exit(EXIT_FAILURE);
720             }
721             seen_aio = true;
722             if (!strcmp(optarg, "native")) {
723                 flags |= BDRV_O_NATIVE_AIO;
724             } else if (!strcmp(optarg, "threads")) {
725                 /* this is the default */
726             } else {
727                error_report("invalid aio mode `%s'", optarg);
728                exit(EXIT_FAILURE);
729             }
730             break;
731         case QEMU_NBD_OPT_DISCARD:
732             if (seen_discard) {
733                 error_report("--discard can only be specified once");
734                 exit(EXIT_FAILURE);
735             }
736             seen_discard = true;
737             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
738                 error_report("Invalid discard mode `%s'", optarg);
739                 exit(EXIT_FAILURE);
740             }
741             break;
742         case QEMU_NBD_OPT_DETECT_ZEROES:
743             detect_zeroes =
744                 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup,
745                                 optarg,
746                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
747                                 &local_err);
748             if (local_err) {
749                 error_reportf_err(local_err,
750                                   "Failed to parse detect_zeroes mode: ");
751                 exit(EXIT_FAILURE);
752             }
753             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
754                 !(flags & BDRV_O_UNMAP)) {
755                 error_report("setting detect-zeroes to unmap is not allowed "
756                              "without setting discard operation to unmap");
757                 exit(EXIT_FAILURE);
758             }
759             break;
760         case 'b':
761             bindto = optarg;
762             break;
763         case 'p':
764             port = optarg;
765             break;
766         case 'o':
767             if (qemu_strtou64(optarg, NULL, 0, &dev_offset) < 0) {
768                 error_report("Invalid offset '%s'", optarg);
769                 exit(EXIT_FAILURE);
770             }
771             break;
772         case 'l':
773             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
774                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
775                                                   optarg, false);
776                 if (!sn_opts) {
777                     error_report("Failed in parsing snapshot param `%s'",
778                                  optarg);
779                     exit(EXIT_FAILURE);
780                 }
781             } else {
782                 sn_id_or_name = optarg;
783             }
784             /* fall through */
785         case 'r':
786             readonly = true;
787             flags &= ~BDRV_O_RDWR;
788             break;
789         case 'P':
790             warn_report("The '-P' option is deprecated; use --image-opts with "
791                         "a raw device wrapper for subset exports instead");
792             if (qemu_strtoi(optarg, NULL, 0, &partition) < 0 ||
793                 partition < 1 || partition > 8) {
794                 error_report("Invalid partition '%s'", optarg);
795                 exit(EXIT_FAILURE);
796             }
797             break;
798         case 'B':
799             bitmap = optarg;
800             break;
801         case 'k':
802             sockpath = optarg;
803             if (sockpath[0] != '/') {
804                 error_report("socket path must be absolute");
805                 exit(EXIT_FAILURE);
806             }
807             break;
808         case 'd':
809             disconnect = true;
810             break;
811         case 'c':
812             device = optarg;
813             break;
814         case 'e':
815             if (qemu_strtoi(optarg, NULL, 0, &shared) < 0 ||
816                 shared < 1) {
817                 error_report("Invalid shared device number '%s'", optarg);
818                 exit(EXIT_FAILURE);
819             }
820             break;
821         case 'f':
822             fmt = optarg;
823             break;
824         case 't':
825             persistent = 1;
826             break;
827         case 'x':
828             export_name = optarg;
829             break;
830         case 'D':
831             export_description = optarg;
832             break;
833         case 'v':
834             verbose = 1;
835             break;
836         case 'V':
837             version(argv[0]);
838             exit(0);
839             break;
840         case 'h':
841             usage(argv[0]);
842             exit(0);
843             break;
844         case '?':
845             error_report("Try `%s --help' for more information.", argv[0]);
846             exit(EXIT_FAILURE);
847         case QEMU_NBD_OPT_OBJECT: {
848             QemuOpts *opts;
849             opts = qemu_opts_parse_noisily(&qemu_object_opts,
850                                            optarg, true);
851             if (!opts) {
852                 exit(EXIT_FAILURE);
853             }
854         }   break;
855         case QEMU_NBD_OPT_TLSCREDS:
856             tlscredsid = optarg;
857             break;
858         case QEMU_NBD_OPT_IMAGE_OPTS:
859             imageOpts = true;
860             break;
861         case 'T':
862             g_free(trace_file);
863             trace_file = trace_opt_parse(optarg);
864             break;
865         case QEMU_NBD_OPT_TLSAUTHZ:
866             tlsauthz = optarg;
867             break;
868         case QEMU_NBD_OPT_FORK:
869             fork_process = true;
870             break;
871         case 'L':
872             list = true;
873             break;
874         case QEMU_NBD_OPT_PID_FILE:
875             pid_file_name = optarg;
876             break;
877         }
878     }
879 
880     if (list) {
881         if (argc != optind) {
882             error_report("List mode is incompatible with a file name");
883             exit(EXIT_FAILURE);
884         }
885         if (export_name || export_description || dev_offset || partition ||
886             device || disconnect || fmt || sn_id_or_name || bitmap ||
887             seen_aio || seen_discard || seen_cache) {
888             error_report("List mode is incompatible with per-device settings");
889             exit(EXIT_FAILURE);
890         }
891         if (fork_process) {
892             error_report("List mode is incompatible with forking");
893             exit(EXIT_FAILURE);
894         }
895     } else if ((argc - optind) != 1) {
896         error_report("Invalid number of arguments");
897         error_printf("Try `%s --help' for more information.\n", argv[0]);
898         exit(EXIT_FAILURE);
899     } else if (!export_name) {
900         export_name = "";
901     }
902 
903     qemu_opts_foreach(&qemu_object_opts,
904                       user_creatable_add_opts_foreach,
905                       NULL, &error_fatal);
906 
907     if (!trace_init_backends()) {
908         exit(1);
909     }
910     trace_init_file(trace_file);
911     qemu_set_log(LOG_TRACE);
912 
913     socket_activation = check_socket_activation();
914     if (socket_activation == 0) {
915         setup_address_and_port(&bindto, &port);
916     } else {
917         /* Using socket activation - check user didn't use -p etc. */
918         const char *err_msg = socket_activation_validate_opts(device, sockpath,
919                                                               bindto, port,
920                                                               list);
921         if (err_msg != NULL) {
922             error_report("%s", err_msg);
923             exit(EXIT_FAILURE);
924         }
925 
926         /* qemu-nbd can only listen on a single socket.  */
927         if (socket_activation > 1) {
928             error_report("qemu-nbd does not support socket activation with %s > 1",
929                          "LISTEN_FDS");
930             exit(EXIT_FAILURE);
931         }
932     }
933 
934     if (tlscredsid) {
935         if (sockpath) {
936             error_report("TLS is only supported with IPv4/IPv6");
937             exit(EXIT_FAILURE);
938         }
939         if (device) {
940             error_report("TLS is not supported with a host device");
941             exit(EXIT_FAILURE);
942         }
943         if (tlsauthz && list) {
944             error_report("TLS authorization is incompatible with export list");
945             exit(EXIT_FAILURE);
946         }
947         tlscreds = nbd_get_tls_creds(tlscredsid, list, &local_err);
948         if (local_err) {
949             error_report("Failed to get TLS creds %s",
950                          error_get_pretty(local_err));
951             exit(EXIT_FAILURE);
952         }
953     } else {
954         if (tlsauthz) {
955             error_report("--tls-authz is not permitted without --tls-creds");
956             exit(EXIT_FAILURE);
957         }
958     }
959 
960     if (list) {
961         saddr = nbd_build_socket_address(sockpath, bindto, port);
962         return qemu_nbd_client_list(saddr, tlscreds, bindto);
963     }
964 
965 #if !HAVE_NBD_DEVICE
966     if (disconnect || device) {
967         error_report("Kernel /dev/nbdN support not available");
968         exit(EXIT_FAILURE);
969     }
970 #else /* HAVE_NBD_DEVICE */
971     if (disconnect) {
972         int nbdfd = open(argv[optind], O_RDWR);
973         if (nbdfd < 0) {
974             error_report("Cannot open %s: %s", argv[optind],
975                          strerror(errno));
976             exit(EXIT_FAILURE);
977         }
978         nbd_disconnect(nbdfd);
979 
980         close(nbdfd);
981 
982         printf("%s disconnected\n", argv[optind]);
983 
984         return 0;
985     }
986 #endif
987 
988     if ((device && !verbose) || fork_process) {
989         int stderr_fd[2];
990         pid_t pid;
991         int ret;
992 
993         if (qemu_pipe(stderr_fd) < 0) {
994             error_report("Error setting up communication pipe: %s",
995                          strerror(errno));
996             exit(EXIT_FAILURE);
997         }
998 
999         /* Now daemonize, but keep a communication channel open to
1000          * print errors and exit with the proper status code.
1001          */
1002         pid = fork();
1003         if (pid < 0) {
1004             error_report("Failed to fork: %s", strerror(errno));
1005             exit(EXIT_FAILURE);
1006         } else if (pid == 0) {
1007             close(stderr_fd[0]);
1008 
1009             old_stderr = dup(STDERR_FILENO);
1010             ret = qemu_daemon(1, 0);
1011 
1012             /* Temporarily redirect stderr to the parent's pipe...  */
1013             dup2(stderr_fd[1], STDERR_FILENO);
1014             if (ret < 0) {
1015                 error_report("Failed to daemonize: %s", strerror(errno));
1016                 exit(EXIT_FAILURE);
1017             }
1018 
1019             /* ... close the descriptor we inherited and go on.  */
1020             close(stderr_fd[1]);
1021         } else {
1022             bool errors = false;
1023             char *buf;
1024 
1025             /* In the parent.  Print error messages from the child until
1026              * it closes the pipe.
1027              */
1028             close(stderr_fd[1]);
1029             buf = g_malloc(1024);
1030             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
1031                 errors = true;
1032                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
1033                 if (ret < 0) {
1034                     exit(EXIT_FAILURE);
1035                 }
1036             }
1037             if (ret < 0) {
1038                 error_report("Cannot read from daemon: %s",
1039                              strerror(errno));
1040                 exit(EXIT_FAILURE);
1041             }
1042 
1043             /* Usually the daemon should not print any message.
1044              * Exit with zero status in that case.
1045              */
1046             exit(errors);
1047         }
1048     }
1049 
1050     if (device != NULL && sockpath == NULL) {
1051         sockpath = g_malloc(128);
1052         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
1053     }
1054 
1055     server = qio_net_listener_new();
1056     if (socket_activation == 0) {
1057         saddr = nbd_build_socket_address(sockpath, bindto, port);
1058         if (qio_net_listener_open_sync(server, saddr, 1, &local_err) < 0) {
1059             object_unref(OBJECT(server));
1060             error_report_err(local_err);
1061             exit(EXIT_FAILURE);
1062         }
1063     } else {
1064         size_t i;
1065         /* See comment in check_socket_activation above. */
1066         for (i = 0; i < socket_activation; i++) {
1067             QIOChannelSocket *sioc;
1068             sioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD + i,
1069                                              &local_err);
1070             if (sioc == NULL) {
1071                 object_unref(OBJECT(server));
1072                 error_report("Failed to use socket activation: %s",
1073                              error_get_pretty(local_err));
1074                 exit(EXIT_FAILURE);
1075             }
1076             qio_net_listener_add(server, sioc);
1077             object_unref(OBJECT(sioc));
1078         }
1079     }
1080 
1081     if (qemu_init_main_loop(&local_err)) {
1082         error_report_err(local_err);
1083         exit(EXIT_FAILURE);
1084     }
1085     bdrv_init();
1086     atexit(qemu_nbd_shutdown);
1087 
1088     srcpath = argv[optind];
1089     if (imageOpts) {
1090         QemuOpts *opts;
1091         if (fmt) {
1092             error_report("--image-opts and -f are mutually exclusive");
1093             exit(EXIT_FAILURE);
1094         }
1095         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
1096         if (!opts) {
1097             qemu_opts_reset(&file_opts);
1098             exit(EXIT_FAILURE);
1099         }
1100         options = qemu_opts_to_qdict(opts, NULL);
1101         qemu_opts_reset(&file_opts);
1102         blk = blk_new_open(NULL, NULL, options, flags, &local_err);
1103     } else {
1104         if (fmt) {
1105             options = qdict_new();
1106             qdict_put_str(options, "driver", fmt);
1107         }
1108         blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
1109     }
1110 
1111     if (!blk) {
1112         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
1113                           argv[optind]);
1114         exit(EXIT_FAILURE);
1115     }
1116     bs = blk_bs(blk);
1117 
1118     blk_set_enable_write_cache(blk, !writethrough);
1119 
1120     if (sn_opts) {
1121         ret = bdrv_snapshot_load_tmp(bs,
1122                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
1123                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
1124                                      &local_err);
1125     } else if (sn_id_or_name) {
1126         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
1127                                                    &local_err);
1128     }
1129     if (ret < 0) {
1130         error_reportf_err(local_err, "Failed to load snapshot: ");
1131         exit(EXIT_FAILURE);
1132     }
1133 
1134     bs->detect_zeroes = detect_zeroes;
1135     fd_size = blk_getlength(blk);
1136     if (fd_size < 0) {
1137         error_report("Failed to determine the image length: %s",
1138                      strerror(-fd_size));
1139         exit(EXIT_FAILURE);
1140     }
1141 
1142     if (dev_offset >= fd_size) {
1143         error_report("Offset (%" PRIu64 ") has to be smaller than the image "
1144                      "size (%" PRId64 ")", dev_offset, fd_size);
1145         exit(EXIT_FAILURE);
1146     }
1147     fd_size -= dev_offset;
1148 
1149     if (partition) {
1150         uint64_t limit;
1151 
1152         if (dev_offset) {
1153             error_report("Cannot request partition and offset together");
1154             exit(EXIT_FAILURE);
1155         }
1156         ret = find_partition(blk, partition, &dev_offset, &limit);
1157         if (ret < 0) {
1158             error_report("Could not find partition %d: %s", partition,
1159                          strerror(-ret));
1160             exit(EXIT_FAILURE);
1161         }
1162         /*
1163          * MBR partition limits are (32-bit << 9); this assert lets
1164          * the compiler know that we can't overflow 64 bits.
1165          */
1166         assert(dev_offset + limit >= dev_offset);
1167         if (dev_offset + limit > fd_size) {
1168             error_report("Discovered partition %d at offset %" PRIu64
1169                          " size %" PRIu64 ", but size exceeds file length %"
1170                          PRId64, partition, dev_offset, limit, fd_size);
1171             exit(EXIT_FAILURE);
1172         }
1173         fd_size = limit;
1174     }
1175 
1176     export = nbd_export_new(bs, dev_offset, fd_size, export_name,
1177                             export_description, bitmap, readonly, shared > 1,
1178                             nbd_export_closed, writethrough, NULL,
1179                             &error_fatal);
1180 
1181     if (device) {
1182 #if HAVE_NBD_DEVICE
1183         int ret;
1184 
1185         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
1186         if (ret != 0) {
1187             error_report("Failed to create client thread: %s", strerror(ret));
1188             exit(EXIT_FAILURE);
1189         }
1190 #endif
1191     } else {
1192         /* Shut up GCC warnings.  */
1193         memset(&client_thread, 0, sizeof(client_thread));
1194     }
1195 
1196     nbd_update_server_watch();
1197 
1198     if (pid_file_name) {
1199         qemu_write_pidfile(pid_file_name, &error_fatal);
1200     }
1201 
1202     /* now when the initialization is (almost) complete, chdir("/")
1203      * to free any busy filesystems */
1204     if (chdir("/") < 0) {
1205         error_report("Could not chdir to root directory: %s",
1206                      strerror(errno));
1207         exit(EXIT_FAILURE);
1208     }
1209 
1210     if (fork_process) {
1211         dup2(old_stderr, STDERR_FILENO);
1212         close(old_stderr);
1213     }
1214 
1215     state = RUNNING;
1216     do {
1217         main_loop_wait(false);
1218         if (state == TERMINATE) {
1219             state = TERMINATING;
1220             nbd_export_close(export);
1221             nbd_export_put(export);
1222             export = NULL;
1223         }
1224     } while (state != TERMINATED);
1225 
1226     blk_unref(blk);
1227     if (sockpath) {
1228         unlink(sockpath);
1229     }
1230 
1231     qemu_opts_del(sn_opts);
1232 
1233     if (device) {
1234         void *ret;
1235         pthread_join(client_thread, &ret);
1236         exit(ret != NULL);
1237     } else {
1238         exit(EXIT_SUCCESS);
1239     }
1240 }
1241