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