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19#include "qemu-common.h"
20#include "block/block.h"
21#include "block/nbd.h"
22#include "qemu/main-loop.h"
23#include "qemu/sockets.h"
24#include "qemu/error-report.h"
25#include "block/snapshot.h"
26
27#include <stdarg.h>
28#include <stdio.h>
29#include <getopt.h>
30#include <err.h>
31#include <sys/types.h>
32#include <sys/socket.h>
33#include <netinet/in.h>
34#include <netinet/tcp.h>
35#include <arpa/inet.h>
36#include <signal.h>
37#include <libgen.h>
38#include <pthread.h>
39
40#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
41#define QEMU_NBD_OPT_CACHE 1
42#define QEMU_NBD_OPT_AIO 2
43#define QEMU_NBD_OPT_DISCARD 3
44
45static NBDExport *exp;
46static int verbose;
47static char *srcpath;
48static char *sockpath;
49static int persistent = 0;
50static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
51static int shared = 1;
52static int nb_fds;
53
54static void usage(const char *name)
55{
56 (printf) (
57"Usage: %s [OPTIONS] FILE\n"
58"QEMU Disk Network Block Device Server\n"
59"\n"
60" -h, --help display this help and exit\n"
61" -V, --version output version information and exit\n"
62"\n"
63"Connection properties:\n"
64" -p, --port=PORT port to listen on (default `%d')\n"
65" -b, --bind=IFACE interface to bind to (default `0.0.0.0')\n"
66" -k, --socket=PATH path to the unix socket\n"
67" (default '"SOCKET_PATH"')\n"
68" -e, --shared=NUM device can be shared by NUM clients (default '1')\n"
69" -t, --persistent don't exit on the last connection\n"
70" -v, --verbose display extra debugging information\n"
71"\n"
72"Exposing part of the image:\n"
73" -o, --offset=OFFSET offset into the image\n"
74" -P, --partition=NUM only expose partition NUM\n"
75"\n"
76#ifdef __linux__
77"Kernel NBD client support:\n"
78" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
79" -d, --disconnect disconnect the specified device\n"
80"\n"
81#endif
82"\n"
83"Block device options:\n"
84" -f, --format=FORMAT set image format (raw, qcow2, ...)\n"
85" -r, --read-only export read-only\n"
86" -s, --snapshot use FILE as an external snapshot, create a temporary\n"
87" file with backing_file=FILE, redirect the write to\n"
88" the temporary one\n"
89" -l, --load-snapshot=SNAPSHOT_PARAM\n"
90" load an internal snapshot inside FILE and export it\n"
91" as an read-only device, SNAPSHOT_PARAM format is\n"
92" 'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
93" '[ID_OR_NAME]'\n"
94" -n, --nocache disable host cache\n"
95" --cache=MODE set cache mode (none, writeback, ...)\n"
96#ifdef CONFIG_LINUX_AIO
97" --aio=MODE set AIO mode (native or threads)\n"
98#endif
99"\n"
100"Report bugs to <qemu-devel@nongnu.org>\n"
101 , name, NBD_DEFAULT_PORT, "DEVICE");
102}
103
104static void version(const char *name)
105{
106 printf(
107"%s version 0.0.1\n"
108"Written by Anthony Liguori.\n"
109"\n"
110"Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
111"This is free software; see the source for copying conditions. There is NO\n"
112"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
113 , name);
114}
115
116struct partition_record
117{
118 uint8_t bootable;
119 uint8_t start_head;
120 uint32_t start_cylinder;
121 uint8_t start_sector;
122 uint8_t system;
123 uint8_t end_head;
124 uint8_t end_cylinder;
125 uint8_t end_sector;
126 uint32_t start_sector_abs;
127 uint32_t nb_sectors_abs;
128};
129
130static void read_partition(uint8_t *p, struct partition_record *r)
131{
132 r->bootable = p[0];
133 r->start_head = p[1];
134 r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
135 r->start_sector = p[2] & 0x3f;
136 r->system = p[4];
137 r->end_head = p[5];
138 r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
139 r->end_sector = p[6] & 0x3f;
140 r->start_sector_abs = p[8] | p[9] << 8 | p[10] << 16 | p[11] << 24;
141 r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24;
142}
143
144static int find_partition(BlockDriverState *bs, int partition,
145 off_t *offset, off_t *size)
146{
147 struct partition_record mbr[4];
148 uint8_t data[512];
149 int i;
150 int ext_partnum = 4;
151 int ret;
152
153 if ((ret = bdrv_read(bs, 0, data, 1)) < 0) {
154 errno = -ret;
155 err(EXIT_FAILURE, "error while reading");
156 }
157
158 if (data[510] != 0x55 || data[511] != 0xaa) {
159 return -EINVAL;
160 }
161
162 for (i = 0; i < 4; i++) {
163 read_partition(&data[446 + 16 * i], &mbr[i]);
164
165 if (!mbr[i].nb_sectors_abs)
166 continue;
167
168 if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
169 struct partition_record ext[4];
170 uint8_t data1[512];
171 int j;
172
173 if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) {
174 errno = -ret;
175 err(EXIT_FAILURE, "error while reading");
176 }
177
178 for (j = 0; j < 4; j++) {
179 read_partition(&data1[446 + 16 * j], &ext[j]);
180 if (!ext[j].nb_sectors_abs)
181 continue;
182
183 if ((ext_partnum + j + 1) == partition) {
184 *offset = (uint64_t)ext[j].start_sector_abs << 9;
185 *size = (uint64_t)ext[j].nb_sectors_abs << 9;
186 return 0;
187 }
188 }
189 ext_partnum += 4;
190 } else if ((i + 1) == partition) {
191 *offset = (uint64_t)mbr[i].start_sector_abs << 9;
192 *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
193 return 0;
194 }
195 }
196
197 return -ENOENT;
198}
199
200static void termsig_handler(int signum)
201{
202 state = TERMINATE;
203 qemu_notify_event();
204}
205
206static void combine_addr(char *buf, size_t len, const char* address,
207 uint16_t port)
208{
209
210 if (strstr(address, ":")) {
211 snprintf(buf, len, "[%s]:%u", address, port);
212 } else {
213 snprintf(buf, len, "%s:%u", address, port);
214 }
215}
216
217static int tcp_socket_incoming(const char *address, uint16_t port)
218{
219 char address_and_port[128];
220 Error *local_err = NULL;
221
222 combine_addr(address_and_port, 128, address, port);
223 int fd = inet_listen(address_and_port, NULL, 0, SOCK_STREAM, 0, &local_err);
224
225 if (local_err != NULL) {
226 error_report("%s", error_get_pretty(local_err));
227 error_free(local_err);
228 }
229 return fd;
230}
231
232static int unix_socket_incoming(const char *path)
233{
234 Error *local_err = NULL;
235 int fd = unix_listen(path, NULL, 0, &local_err);
236
237 if (local_err != NULL) {
238 error_report("%s", error_get_pretty(local_err));
239 error_free(local_err);
240 }
241 return fd;
242}
243
244static int unix_socket_outgoing(const char *path)
245{
246 Error *local_err = NULL;
247 int fd = unix_connect(path, &local_err);
248
249 if (local_err != NULL) {
250 error_report("%s", error_get_pretty(local_err));
251 error_free(local_err);
252 }
253 return fd;
254}
255
256static void *show_parts(void *arg)
257{
258 char *device = arg;
259 int nbd;
260
261
262
263
264
265
266 nbd = open(device, O_RDWR);
267 if (nbd >= 0) {
268 close(nbd);
269 }
270 return NULL;
271}
272
273static void *nbd_client_thread(void *arg)
274{
275 char *device = arg;
276 off_t size;
277 size_t blocksize;
278 uint32_t nbdflags;
279 int fd, sock;
280 int ret;
281 pthread_t show_parts_thread;
282
283 sock = unix_socket_outgoing(sockpath);
284 if (sock < 0) {
285 goto out;
286 }
287
288 ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
289 &size, &blocksize);
290 if (ret < 0) {
291 goto out_socket;
292 }
293
294 fd = open(device, O_RDWR);
295 if (fd < 0) {
296
297 fprintf(stderr, "Failed to open %s: %m\n", device);
298 goto out_socket;
299 }
300
301 ret = nbd_init(fd, sock, nbdflags, size, blocksize);
302 if (ret < 0) {
303 goto out_fd;
304 }
305
306
307 pthread_create(&show_parts_thread, NULL, show_parts, device);
308
309 if (verbose) {
310 fprintf(stderr, "NBD device %s is now connected to %s\n",
311 device, srcpath);
312 } else {
313
314 dup2(STDOUT_FILENO, STDERR_FILENO);
315 }
316
317 ret = nbd_client(fd);
318 if (ret) {
319 goto out_fd;
320 }
321 close(fd);
322 kill(getpid(), SIGTERM);
323 return (void *) EXIT_SUCCESS;
324
325out_fd:
326 close(fd);
327out_socket:
328 closesocket(sock);
329out:
330 kill(getpid(), SIGTERM);
331 return (void *) EXIT_FAILURE;
332}
333
334static int nbd_can_accept(void *opaque)
335{
336 return nb_fds < shared;
337}
338
339static void nbd_export_closed(NBDExport *exp)
340{
341 assert(state == TERMINATING);
342 state = TERMINATED;
343}
344
345static void nbd_client_closed(NBDClient *client)
346{
347 nb_fds--;
348 if (nb_fds == 0 && !persistent && state == RUNNING) {
349 state = TERMINATE;
350 }
351 qemu_notify_event();
352 nbd_client_put(client);
353}
354
355static void nbd_accept(void *opaque)
356{
357 int server_fd = (uintptr_t) opaque;
358 struct sockaddr_in addr;
359 socklen_t addr_len = sizeof(addr);
360
361 int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
362 if (fd < 0) {
363 perror("accept");
364 return;
365 }
366
367 if (state >= TERMINATE) {
368 close(fd);
369 return;
370 }
371
372 if (nbd_client_new(exp, fd, nbd_client_closed)) {
373 nb_fds++;
374 } else {
375 shutdown(fd, 2);
376 close(fd);
377 }
378}
379
380int main(int argc, char **argv)
381{
382 BlockDriverState *bs;
383 BlockDriver *drv;
384 off_t dev_offset = 0;
385 uint32_t nbdflags = 0;
386 bool disconnect = false;
387 const char *bindto = "0.0.0.0";
388 char *device = NULL;
389 int port = NBD_DEFAULT_PORT;
390 off_t fd_size;
391 QemuOpts *sn_opts = NULL;
392 const char *sn_id_or_name = NULL;
393 const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:";
394 struct option lopt[] = {
395 { "help", 0, NULL, 'h' },
396 { "version", 0, NULL, 'V' },
397 { "bind", 1, NULL, 'b' },
398 { "port", 1, NULL, 'p' },
399 { "socket", 1, NULL, 'k' },
400 { "offset", 1, NULL, 'o' },
401 { "read-only", 0, NULL, 'r' },
402 { "partition", 1, NULL, 'P' },
403 { "connect", 1, NULL, 'c' },
404 { "disconnect", 0, NULL, 'd' },
405 { "snapshot", 0, NULL, 's' },
406 { "load-snapshot", 1, NULL, 'l' },
407 { "nocache", 0, NULL, 'n' },
408 { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
409#ifdef CONFIG_LINUX_AIO
410 { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
411#endif
412 { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
413 { "shared", 1, NULL, 'e' },
414 { "format", 1, NULL, 'f' },
415 { "persistent", 0, NULL, 't' },
416 { "verbose", 0, NULL, 'v' },
417 { NULL, 0, NULL, 0 }
418 };
419 int ch;
420 int opt_ind = 0;
421 int li;
422 char *end;
423 int flags = BDRV_O_RDWR;
424 int partition = -1;
425 int ret;
426 int fd;
427 bool seen_cache = false;
428 bool seen_discard = false;
429#ifdef CONFIG_LINUX_AIO
430 bool seen_aio = false;
431#endif
432 pthread_t client_thread;
433 const char *fmt = NULL;
434 Error *local_err = NULL;
435
436
437
438
439 struct sigaction sa_sigterm;
440 memset(&sa_sigterm, 0, sizeof(sa_sigterm));
441 sa_sigterm.sa_handler = termsig_handler;
442 sigaction(SIGTERM, &sa_sigterm, NULL);
443 qemu_init_exec_dir(argv[0]);
444
445 while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
446 switch (ch) {
447 case 's':
448 flags |= BDRV_O_SNAPSHOT;
449 break;
450 case 'n':
451 optarg = (char *) "none";
452
453 case QEMU_NBD_OPT_CACHE:
454 if (seen_cache) {
455 errx(EXIT_FAILURE, "-n and --cache can only be specified once");
456 }
457 seen_cache = true;
458 if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
459 errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg);
460 }
461 break;
462#ifdef CONFIG_LINUX_AIO
463 case QEMU_NBD_OPT_AIO:
464 if (seen_aio) {
465 errx(EXIT_FAILURE, "--aio can only be specified once");
466 }
467 seen_aio = true;
468 if (!strcmp(optarg, "native")) {
469 flags |= BDRV_O_NATIVE_AIO;
470 } else if (!strcmp(optarg, "threads")) {
471
472 } else {
473 errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg);
474 }
475 break;
476#endif
477 case QEMU_NBD_OPT_DISCARD:
478 if (seen_discard) {
479 errx(EXIT_FAILURE, "--discard can only be specified once");
480 }
481 seen_discard = true;
482 if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
483 errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg);
484 }
485 break;
486 case 'b':
487 bindto = optarg;
488 break;
489 case 'p':
490 li = strtol(optarg, &end, 0);
491 if (*end) {
492 errx(EXIT_FAILURE, "Invalid port `%s'", optarg);
493 }
494 if (li < 1 || li > 65535) {
495 errx(EXIT_FAILURE, "Port out of range `%s'", optarg);
496 }
497 port = (uint16_t)li;
498 break;
499 case 'o':
500 dev_offset = strtoll (optarg, &end, 0);
501 if (*end) {
502 errx(EXIT_FAILURE, "Invalid offset `%s'", optarg);
503 }
504 if (dev_offset < 0) {
505 errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
506 }
507 break;
508 case 'l':
509 if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
510 sn_opts = qemu_opts_parse(&internal_snapshot_opts, optarg, 0);
511 if (!sn_opts) {
512 errx(EXIT_FAILURE, "Failed in parsing snapshot param `%s'",
513 optarg);
514 }
515 } else {
516 sn_id_or_name = optarg;
517 }
518
519 case 'r':
520 nbdflags |= NBD_FLAG_READ_ONLY;
521 flags &= ~BDRV_O_RDWR;
522 break;
523 case 'P':
524 partition = strtol(optarg, &end, 0);
525 if (*end)
526 errx(EXIT_FAILURE, "Invalid partition `%s'", optarg);
527 if (partition < 1 || partition > 8)
528 errx(EXIT_FAILURE, "Invalid partition %d", partition);
529 break;
530 case 'k':
531 sockpath = optarg;
532 if (sockpath[0] != '/')
533 errx(EXIT_FAILURE, "socket path must be absolute\n");
534 break;
535 case 'd':
536 disconnect = true;
537 break;
538 case 'c':
539 device = optarg;
540 break;
541 case 'e':
542 shared = strtol(optarg, &end, 0);
543 if (*end) {
544 errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg);
545 }
546 if (shared < 1) {
547 errx(EXIT_FAILURE, "Shared device number must be greater than 0\n");
548 }
549 break;
550 case 'f':
551 fmt = optarg;
552 break;
553 case 't':
554 persistent = 1;
555 break;
556 case 'v':
557 verbose = 1;
558 break;
559 case 'V':
560 version(argv[0]);
561 exit(0);
562 break;
563 case 'h':
564 usage(argv[0]);
565 exit(0);
566 break;
567 case '?':
568 errx(EXIT_FAILURE, "Try `%s --help' for more information.",
569 argv[0]);
570 }
571 }
572
573 if ((argc - optind) != 1) {
574 errx(EXIT_FAILURE, "Invalid number of argument.\n"
575 "Try `%s --help' for more information.",
576 argv[0]);
577 }
578
579 if (disconnect) {
580 fd = open(argv[optind], O_RDWR);
581 if (fd < 0) {
582 err(EXIT_FAILURE, "Cannot open %s", argv[optind]);
583 }
584 nbd_disconnect(fd);
585
586 close(fd);
587
588 printf("%s disconnected\n", argv[optind]);
589
590 return 0;
591 }
592
593 if (device && !verbose) {
594 int stderr_fd[2];
595 pid_t pid;
596 int ret;
597
598 if (qemu_pipe(stderr_fd) < 0) {
599 err(EXIT_FAILURE, "Error setting up communication pipe");
600 }
601
602
603
604
605 pid = fork();
606 if (pid == 0) {
607 close(stderr_fd[0]);
608 ret = qemu_daemon(1, 0);
609
610
611 dup2(stderr_fd[1], STDERR_FILENO);
612 if (ret < 0) {
613 err(EXIT_FAILURE, "Failed to daemonize");
614 }
615
616
617 close(stderr_fd[1]);
618 } else {
619 bool errors = false;
620 char *buf;
621
622
623
624
625 close(stderr_fd[1]);
626 buf = g_malloc(1024);
627 while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
628 errors = true;
629 ret = qemu_write_full(STDERR_FILENO, buf, ret);
630 if (ret < 0) {
631 exit(EXIT_FAILURE);
632 }
633 }
634 if (ret < 0) {
635 err(EXIT_FAILURE, "Cannot read from daemon");
636 }
637
638
639
640
641 exit(errors);
642 }
643 }
644
645 if (device != NULL && sockpath == NULL) {
646 sockpath = g_malloc(128);
647 snprintf(sockpath, 128, SOCKET_PATH, basename(device));
648 }
649
650 qemu_init_main_loop();
651 bdrv_init();
652 atexit(bdrv_close_all);
653
654 if (fmt) {
655 drv = bdrv_find_format(fmt);
656 if (!drv) {
657 errx(EXIT_FAILURE, "Unknown file format '%s'", fmt);
658 }
659 } else {
660 drv = NULL;
661 }
662
663 bs = bdrv_new("hda", &error_abort);
664
665 srcpath = argv[optind];
666 ret = bdrv_open(&bs, srcpath, NULL, NULL, flags, drv, &local_err);
667 if (ret < 0) {
668 errno = -ret;
669 err(EXIT_FAILURE, "Failed to bdrv_open '%s': %s", argv[optind],
670 error_get_pretty(local_err));
671 }
672
673 if (sn_opts) {
674 ret = bdrv_snapshot_load_tmp(bs,
675 qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
676 qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
677 &local_err);
678 } else if (sn_id_or_name) {
679 ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
680 &local_err);
681 }
682 if (ret < 0) {
683 errno = -ret;
684 err(EXIT_FAILURE,
685 "Failed to load snapshot: %s",
686 error_get_pretty(local_err));
687 }
688
689 fd_size = bdrv_getlength(bs);
690
691 if (partition != -1) {
692 ret = find_partition(bs, partition, &dev_offset, &fd_size);
693 if (ret < 0) {
694 errno = -ret;
695 err(EXIT_FAILURE, "Could not find partition %d", partition);
696 }
697 }
698
699 exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed);
700
701 if (sockpath) {
702 fd = unix_socket_incoming(sockpath);
703 } else {
704 fd = tcp_socket_incoming(bindto, port);
705 }
706
707 if (fd < 0) {
708 return 1;
709 }
710
711 if (device) {
712 int ret;
713
714 ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
715 if (ret != 0) {
716 errx(EXIT_FAILURE, "Failed to create client thread: %s",
717 strerror(ret));
718 }
719 } else {
720
721 memset(&client_thread, 0, sizeof(client_thread));
722 }
723
724 qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
725 (void *)(uintptr_t)fd);
726
727
728
729 if (chdir("/") < 0) {
730 err(EXIT_FAILURE, "Could not chdir to root directory");
731 }
732
733 state = RUNNING;
734 do {
735 main_loop_wait(false);
736 if (state == TERMINATE) {
737 state = TERMINATING;
738 nbd_export_close(exp);
739 nbd_export_put(exp);
740 exp = NULL;
741 }
742 } while (state != TERMINATED);
743
744 bdrv_close(bs);
745 if (sockpath) {
746 unlink(sockpath);
747 }
748
749 if (sn_opts) {
750 qemu_opts_del(sn_opts);
751 }
752
753 if (device) {
754 void *ret;
755 pthread_join(client_thread, &ret);
756 exit(ret != NULL);
757 } else {
758 exit(EXIT_SUCCESS);
759 }
760}
761
