xref: /freebsd/sbin/ggate/ggatec/ggatec.c (revision c1d255d3)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2004 Pawel Jakub Dawidek <pjd@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <stdint.h>
34 #include <fcntl.h>
35 #include <unistd.h>
36 #include <string.h>
37 #include <ctype.h>
38 #include <inttypes.h>
39 #include <libgen.h>
40 #include <pthread.h>
41 #include <signal.h>
42 #include <err.h>
43 #include <errno.h>
44 #include <assert.h>
45 
46 #include <sys/param.h>
47 #include <sys/ioctl.h>
48 #include <sys/socket.h>
49 #include <sys/sysctl.h>
50 #include <sys/syslog.h>
51 #include <sys/time.h>
52 #include <sys/bio.h>
53 #include <netinet/in.h>
54 #include <netinet/tcp.h>
55 #include <arpa/inet.h>
56 
57 #include <geom/gate/g_gate.h>
58 #include "ggate.h"
59 
60 
61 static enum { UNSET, CREATE, DESTROY, LIST, RESCUE } action = UNSET;
62 
63 static const char *path = NULL;
64 static const char *host = NULL;
65 static int unit = G_GATE_UNIT_AUTO;
66 static unsigned flags = 0;
67 static int force = 0;
68 static unsigned queue_size = G_GATE_QUEUE_SIZE;
69 static unsigned port = G_GATE_PORT;
70 static off_t mediasize;
71 static unsigned sectorsize = 0;
72 static unsigned timeout = G_GATE_TIMEOUT;
73 static int sendfd, recvfd;
74 static uint32_t token;
75 static pthread_t sendtd, recvtd;
76 static int reconnect;
77 
78 static void
79 usage(void)
80 {
81 
82 	fprintf(stderr, "usage: %s create [-nv] [-o <ro|wo|rw>] [-p port] "
83 	    "[-q queue_size] [-R rcvbuf] [-S sndbuf] [-s sectorsize] "
84 	    "[-t timeout] [-u unit] <host> <path>\n", getprogname());
85 	fprintf(stderr, "       %s rescue [-nv] [-o <ro|wo|rw>] [-p port] "
86 	    "[-R rcvbuf] [-S sndbuf] <-u unit> <host> <path>\n", getprogname());
87 	fprintf(stderr, "       %s destroy [-f] <-u unit>\n", getprogname());
88 	fprintf(stderr, "       %s list [-v] [-u unit]\n", getprogname());
89 	exit(EXIT_FAILURE);
90 }
91 
92 static void *
93 send_thread(void *arg __unused)
94 {
95 	struct g_gate_ctl_io ggio;
96 	struct g_gate_hdr hdr;
97 	char buf[MAXPHYS];
98 	ssize_t data;
99 	int error;
100 
101 	g_gate_log(LOG_NOTICE, "%s: started!", __func__);
102 
103 	ggio.gctl_version = G_GATE_VERSION;
104 	ggio.gctl_unit = unit;
105 	ggio.gctl_data = buf;
106 
107 	for (;;) {
108 		ggio.gctl_length = sizeof(buf);
109 		ggio.gctl_error = 0;
110 		g_gate_ioctl(G_GATE_CMD_START, &ggio);
111 		error = ggio.gctl_error;
112 		switch (error) {
113 		case 0:
114 			break;
115 		case ECANCELED:
116 			if (reconnect)
117 				break;
118 			/* Exit gracefully. */
119 			g_gate_close_device();
120 			exit(EXIT_SUCCESS);
121 #if 0
122 		case ENOMEM:
123 			/* Buffer too small. */
124 			ggio.gctl_data = realloc(ggio.gctl_data,
125 			    ggio.gctl_length);
126 			if (ggio.gctl_data != NULL) {
127 				bsize = ggio.gctl_length;
128 				goto once_again;
129 			}
130 			/* FALLTHROUGH */
131 #endif
132 		case ENXIO:
133 		default:
134 			g_gate_xlog("ioctl(/dev/%s): %s.", G_GATE_CTL_NAME,
135 			    strerror(error));
136 		}
137 
138 		if (reconnect)
139 			break;
140 
141 		switch (ggio.gctl_cmd) {
142 		case BIO_READ:
143 			hdr.gh_cmd = GGATE_CMD_READ;
144 			break;
145 		case BIO_WRITE:
146 			hdr.gh_cmd = GGATE_CMD_WRITE;
147 			break;
148 		default:
149 			g_gate_log(LOG_NOTICE, "Unknown gctl_cmd: %i", ggio.gctl_cmd);
150 			ggio.gctl_error = EOPNOTSUPP;
151 			g_gate_ioctl(G_GATE_CMD_DONE, &ggio);
152 			continue;
153 		}
154 
155 		/* Don't send requests for more data than we can handle the response for! */
156 		if (ggio.gctl_length > MAXPHYS) {
157 			g_gate_log(LOG_ERR, "Request too big: %zd", ggio.gctl_length);
158 			ggio.gctl_error = EOPNOTSUPP;
159 			g_gate_ioctl(G_GATE_CMD_DONE, &ggio);
160 			continue;
161 		}
162 
163 		hdr.gh_seq = ggio.gctl_seq;
164 		hdr.gh_offset = ggio.gctl_offset;
165 		hdr.gh_length = ggio.gctl_length;
166 		hdr.gh_error = 0;
167 		g_gate_swap2n_hdr(&hdr);
168 
169 		data = g_gate_send(sendfd, &hdr, sizeof(hdr), MSG_NOSIGNAL);
170 		g_gate_log(LOG_DEBUG, "Sent hdr packet.");
171 		g_gate_swap2h_hdr(&hdr);
172 		if (reconnect)
173 			break;
174 		if (data != sizeof(hdr)) {
175 			g_gate_log(LOG_ERR, "Lost connection 1.");
176 			reconnect = 1;
177 			pthread_kill(recvtd, SIGUSR1);
178 			break;
179 		}
180 
181 		if (hdr.gh_cmd == GGATE_CMD_WRITE) {
182 			data = g_gate_send(sendfd, ggio.gctl_data,
183 			    ggio.gctl_length, MSG_NOSIGNAL);
184 			if (reconnect)
185 				break;
186 			if (data != ggio.gctl_length) {
187 				g_gate_log(LOG_ERR, "Lost connection 2 (%zd != %zd).", data, (ssize_t)ggio.gctl_length);
188 				reconnect = 1;
189 				pthread_kill(recvtd, SIGUSR1);
190 				break;
191 			}
192 			g_gate_log(LOG_DEBUG, "Sent %zd bytes (offset=%"
193 			    PRIu64 ", length=%" PRIu32 ").", data,
194 			    hdr.gh_offset, hdr.gh_length);
195 		}
196 	}
197 	g_gate_log(LOG_DEBUG, "%s: Died.", __func__);
198 	return (NULL);
199 }
200 
201 static void *
202 recv_thread(void *arg __unused)
203 {
204 	struct g_gate_ctl_io ggio;
205 	struct g_gate_hdr hdr;
206 	char buf[MAXPHYS];
207 	ssize_t data;
208 
209 	g_gate_log(LOG_NOTICE, "%s: started!", __func__);
210 
211 	ggio.gctl_version = G_GATE_VERSION;
212 	ggio.gctl_unit = unit;
213 	ggio.gctl_data = buf;
214 
215 	for (;;) {
216 		data = g_gate_recv(recvfd, &hdr, sizeof(hdr), MSG_WAITALL);
217 		if (reconnect)
218 			break;
219 		g_gate_swap2h_hdr(&hdr);
220 		if (data != sizeof(hdr)) {
221 			if (data == -1 && errno == EAGAIN)
222 				continue;
223 			g_gate_log(LOG_ERR, "Lost connection 3.");
224 			reconnect = 1;
225 			pthread_kill(sendtd, SIGUSR1);
226 			break;
227 		}
228 		g_gate_log(LOG_DEBUG, "Received hdr packet.");
229 
230 		ggio.gctl_seq = hdr.gh_seq;
231 		ggio.gctl_cmd = hdr.gh_cmd;
232 		ggio.gctl_offset = hdr.gh_offset;
233 		ggio.gctl_length = hdr.gh_length;
234 		ggio.gctl_error = hdr.gh_error;
235 
236 		/* Do not overflow our buffer if there is a bogus response. */
237 		if (ggio.gctl_length > (off_t) sizeof(buf)) {
238 			g_gate_log(LOG_ERR, "Received too big response: %zd", ggio.gctl_length);
239 			break;
240 		}
241 
242 		if (ggio.gctl_error == 0 && ggio.gctl_cmd == GGATE_CMD_READ) {
243 			data = g_gate_recv(recvfd, ggio.gctl_data,
244 			    ggio.gctl_length, MSG_WAITALL);
245 			if (reconnect)
246 				break;
247 			g_gate_log(LOG_DEBUG, "Received data packet.");
248 			if (data != ggio.gctl_length) {
249 				g_gate_log(LOG_ERR, "Lost connection 4.");
250 				reconnect = 1;
251 				pthread_kill(sendtd, SIGUSR1);
252 				break;
253 			}
254 			g_gate_log(LOG_DEBUG, "Received %d bytes (offset=%"
255 			    PRIu64 ", length=%" PRIu32 ").", data,
256 			    hdr.gh_offset, hdr.gh_length);
257 		}
258 
259 		g_gate_ioctl(G_GATE_CMD_DONE, &ggio);
260 	}
261 	g_gate_log(LOG_DEBUG, "%s: Died.", __func__);
262 	pthread_exit(NULL);
263 }
264 
265 static int
266 handshake(int dir)
267 {
268 	struct g_gate_version ver;
269 	struct g_gate_cinit cinit;
270 	struct g_gate_sinit sinit;
271 	struct sockaddr_in serv;
272 	int sfd;
273 
274 	/*
275 	 * Do the network stuff.
276 	 */
277 	bzero(&serv, sizeof(serv));
278 	serv.sin_family = AF_INET;
279 	serv.sin_addr.s_addr = g_gate_str2ip(host);
280 	if (serv.sin_addr.s_addr == INADDR_NONE) {
281 		g_gate_log(LOG_DEBUG, "Invalid IP/host name: %s.", host);
282 		return (-1);
283 	}
284 	serv.sin_port = htons(port);
285 	sfd = socket(AF_INET, SOCK_STREAM, 0);
286 	if (sfd == -1) {
287 		g_gate_log(LOG_DEBUG, "Cannot open socket: %s.",
288 		    strerror(errno));
289 		return (-1);
290 	}
291 
292 	g_gate_socket_settings(sfd);
293 
294 	if (connect(sfd, (struct sockaddr *)&serv, sizeof(serv)) == -1) {
295 		g_gate_log(LOG_DEBUG, "Cannot connect to server: %s.",
296 		    strerror(errno));
297 		close(sfd);
298 		return (-1);
299 	}
300 
301 	g_gate_log(LOG_INFO, "Connected to the server: %s:%d.", host, port);
302 
303 	/*
304 	 * Create and send version packet.
305 	 */
306 	g_gate_log(LOG_DEBUG, "Sending version packet.");
307 	assert(strlen(GGATE_MAGIC) == sizeof(ver.gv_magic));
308 	bcopy(GGATE_MAGIC, ver.gv_magic, sizeof(ver.gv_magic));
309 	ver.gv_version = GGATE_VERSION;
310 	ver.gv_error = 0;
311 	g_gate_swap2n_version(&ver);
312 	if (g_gate_send(sfd, &ver, sizeof(ver), MSG_NOSIGNAL) == -1) {
313 		g_gate_log(LOG_DEBUG, "Error while sending version packet: %s.",
314 		    strerror(errno));
315 		close(sfd);
316 		return (-1);
317 	}
318 	bzero(&ver, sizeof(ver));
319 	if (g_gate_recv(sfd, &ver, sizeof(ver), MSG_WAITALL) == -1) {
320 		g_gate_log(LOG_DEBUG, "Error while receiving data: %s.",
321 		    strerror(errno));
322 		close(sfd);
323 		return (-1);
324 	}
325 	if (ver.gv_error != 0) {
326 		g_gate_log(LOG_DEBUG, "Version verification problem: %s.",
327 		    strerror(errno));
328 		close(sfd);
329 		return (-1);
330 	}
331 
332 	/*
333 	 * Create and send initial packet.
334 	 */
335 	g_gate_log(LOG_DEBUG, "Sending initial packet.");
336 	if (strlcpy(cinit.gc_path, path, sizeof(cinit.gc_path)) >=
337 	    sizeof(cinit.gc_path)) {
338 		g_gate_log(LOG_DEBUG, "Path name too long.");
339 		close(sfd);
340 		return (-1);
341 	}
342 	cinit.gc_flags = flags | dir;
343 	cinit.gc_token = token;
344 	cinit.gc_nconn = 2;
345 	g_gate_swap2n_cinit(&cinit);
346 	if (g_gate_send(sfd, &cinit, sizeof(cinit), MSG_NOSIGNAL) == -1) {
347 	        g_gate_log(LOG_DEBUG, "Error while sending initial packet: %s.",
348 		    strerror(errno));
349 		close(sfd);
350 		return (-1);
351 	}
352 	g_gate_swap2h_cinit(&cinit);
353 
354 	/*
355 	 * Receiving initial packet from server.
356 	 */
357 	g_gate_log(LOG_DEBUG, "Receiving initial packet.");
358 	if (g_gate_recv(sfd, &sinit, sizeof(sinit), MSG_WAITALL) == -1) {
359 		g_gate_log(LOG_DEBUG, "Error while receiving data: %s.",
360 		    strerror(errno));
361 		close(sfd);
362 		return (-1);
363 	}
364 	g_gate_swap2h_sinit(&sinit);
365 	if (sinit.gs_error != 0) {
366 	        g_gate_log(LOG_DEBUG, "Error from server: %s.",
367 		    strerror(sinit.gs_error));
368 		close(sfd);
369 		return (-1);
370 	}
371 	g_gate_log(LOG_DEBUG, "Received initial packet.");
372 
373 	mediasize = sinit.gs_mediasize;
374 	if (sectorsize == 0)
375 		sectorsize = sinit.gs_sectorsize;
376 
377 	return (sfd);
378 }
379 
380 static void
381 mydaemon(void)
382 {
383 
384 	if (g_gate_verbose > 0)
385 		return;
386 	if (daemon(0, 0) == 0)
387 		return;
388 	if (action == CREATE)
389 		g_gate_destroy(unit, 1);
390 	err(EXIT_FAILURE, "Cannot daemonize");
391 }
392 
393 static int
394 g_gatec_connect(void)
395 {
396 
397 	token = arc4random();
398 	/*
399 	 * Our receive descriptor is connected to the send descriptor on the
400 	 * server side.
401 	 */
402 	recvfd = handshake(GGATE_FLAG_SEND);
403 	if (recvfd == -1)
404 		return (0);
405 	/*
406 	 * Our send descriptor is connected to the receive descriptor on the
407 	 * server side.
408 	 */
409 	sendfd = handshake(GGATE_FLAG_RECV);
410 	if (sendfd == -1)
411 		return (0);
412 	return (1);
413 }
414 
415 static void
416 g_gatec_start(void)
417 {
418 	int error;
419 
420 	reconnect = 0;
421 	error = pthread_create(&recvtd, NULL, recv_thread, NULL);
422 	if (error != 0) {
423 		g_gate_destroy(unit, 1);
424 		g_gate_xlog("pthread_create(recv_thread): %s.",
425 		    strerror(error));
426 	}
427 	sendtd = pthread_self();
428 	send_thread(NULL);
429 	/* Disconnected. */
430 	close(sendfd);
431 	close(recvfd);
432 }
433 
434 static void
435 signop(int sig __unused)
436 {
437 
438 	/* Do nothing. */
439 }
440 
441 static void
442 g_gatec_loop(void)
443 {
444 	struct g_gate_ctl_cancel ggioc;
445 
446 	signal(SIGUSR1, signop);
447 	for (;;) {
448 		g_gatec_start();
449 		g_gate_log(LOG_NOTICE, "Disconnected [%s %s]. Connecting...",
450 		    host, path);
451 		while (!g_gatec_connect()) {
452 			sleep(2);
453 			g_gate_log(LOG_NOTICE, "Connecting [%s %s]...", host,
454 			    path);
455 		}
456 		ggioc.gctl_version = G_GATE_VERSION;
457 		ggioc.gctl_unit = unit;
458 		ggioc.gctl_seq = 0;
459 		g_gate_ioctl(G_GATE_CMD_CANCEL, &ggioc);
460 	}
461 }
462 
463 static void
464 g_gatec_create(void)
465 {
466 	struct g_gate_ctl_create ggioc;
467 
468 	if (!g_gatec_connect())
469 		g_gate_xlog("Cannot connect: %s.", strerror(errno));
470 
471 	/*
472 	 * Ok, got both sockets, time to create provider.
473 	 */
474 	memset(&ggioc, 0, sizeof(ggioc));
475 	ggioc.gctl_version = G_GATE_VERSION;
476 	ggioc.gctl_mediasize = mediasize;
477 	ggioc.gctl_sectorsize = sectorsize;
478 	ggioc.gctl_flags = flags;
479 	ggioc.gctl_maxcount = queue_size;
480 	ggioc.gctl_timeout = timeout;
481 	ggioc.gctl_unit = unit;
482 	snprintf(ggioc.gctl_info, sizeof(ggioc.gctl_info), "%s:%u %s", host,
483 	    port, path);
484 	g_gate_ioctl(G_GATE_CMD_CREATE, &ggioc);
485 	if (unit == -1) {
486 		printf("%s%u\n", G_GATE_PROVIDER_NAME, ggioc.gctl_unit);
487 		fflush(stdout);
488 	}
489 	unit = ggioc.gctl_unit;
490 
491 	mydaemon();
492 	g_gatec_loop();
493 }
494 
495 static void
496 g_gatec_rescue(void)
497 {
498 	struct g_gate_ctl_cancel ggioc;
499 
500 	if (!g_gatec_connect())
501 		g_gate_xlog("Cannot connect: %s.", strerror(errno));
502 
503 	ggioc.gctl_version = G_GATE_VERSION;
504 	ggioc.gctl_unit = unit;
505 	ggioc.gctl_seq = 0;
506 	g_gate_ioctl(G_GATE_CMD_CANCEL, &ggioc);
507 
508 	mydaemon();
509 	g_gatec_loop();
510 }
511 
512 int
513 main(int argc, char *argv[])
514 {
515 
516 	if (argc < 2)
517 		usage();
518 	if (strcasecmp(argv[1], "create") == 0)
519 		action = CREATE;
520 	else if (strcasecmp(argv[1], "destroy") == 0)
521 		action = DESTROY;
522 	else if (strcasecmp(argv[1], "list") == 0)
523 		action = LIST;
524 	else if (strcasecmp(argv[1], "rescue") == 0)
525 		action = RESCUE;
526 	else
527 		usage();
528 	argc -= 1;
529 	argv += 1;
530 	for (;;) {
531 		int ch;
532 
533 		ch = getopt(argc, argv, "fno:p:q:R:S:s:t:u:v");
534 		if (ch == -1)
535 			break;
536 		switch (ch) {
537 		case 'f':
538 			if (action != DESTROY)
539 				usage();
540 			force = 1;
541 			break;
542 		case 'n':
543 			if (action != CREATE && action != RESCUE)
544 				usage();
545 			nagle = 0;
546 			break;
547 		case 'o':
548 			if (action != CREATE && action != RESCUE)
549 				usage();
550 			if (strcasecmp("ro", optarg) == 0)
551 				flags = G_GATE_FLAG_READONLY;
552 			else if (strcasecmp("wo", optarg) == 0)
553 				flags = G_GATE_FLAG_WRITEONLY;
554 			else if (strcasecmp("rw", optarg) == 0)
555 				flags = 0;
556 			else {
557 				errx(EXIT_FAILURE,
558 				    "Invalid argument for '-o' option.");
559 			}
560 			break;
561 		case 'p':
562 			if (action != CREATE && action != RESCUE)
563 				usage();
564 			errno = 0;
565 			port = strtoul(optarg, NULL, 10);
566 			if (port == 0 && errno != 0)
567 				errx(EXIT_FAILURE, "Invalid port.");
568 			break;
569 		case 'q':
570 			if (action != CREATE)
571 				usage();
572 			errno = 0;
573 			queue_size = strtoul(optarg, NULL, 10);
574 			if (queue_size == 0 && errno != 0)
575 				errx(EXIT_FAILURE, "Invalid queue_size.");
576 			break;
577 		case 'R':
578 			if (action != CREATE && action != RESCUE)
579 				usage();
580 			errno = 0;
581 			rcvbuf = strtoul(optarg, NULL, 10);
582 			if (rcvbuf == 0 && errno != 0)
583 				errx(EXIT_FAILURE, "Invalid rcvbuf.");
584 			break;
585 		case 'S':
586 			if (action != CREATE && action != RESCUE)
587 				usage();
588 			errno = 0;
589 			sndbuf = strtoul(optarg, NULL, 10);
590 			if (sndbuf == 0 && errno != 0)
591 				errx(EXIT_FAILURE, "Invalid sndbuf.");
592 			break;
593 		case 's':
594 			if (action != CREATE)
595 				usage();
596 			errno = 0;
597 			sectorsize = strtoul(optarg, NULL, 10);
598 			if (sectorsize == 0 && errno != 0)
599 				errx(EXIT_FAILURE, "Invalid sectorsize.");
600 			break;
601 		case 't':
602 			if (action != CREATE)
603 				usage();
604 			errno = 0;
605 			timeout = strtoul(optarg, NULL, 10);
606 			if (timeout == 0 && errno != 0)
607 				errx(EXIT_FAILURE, "Invalid timeout.");
608 			break;
609 		case 'u':
610 			errno = 0;
611 			unit = strtol(optarg, NULL, 10);
612 			if (unit == 0 && errno != 0)
613 				errx(EXIT_FAILURE, "Invalid unit number.");
614 			break;
615 		case 'v':
616 			if (action == DESTROY)
617 				usage();
618 			g_gate_verbose++;
619 			break;
620 		default:
621 			usage();
622 		}
623 	}
624 	argc -= optind;
625 	argv += optind;
626 
627 	switch (action) {
628 	case CREATE:
629 		if (argc != 2)
630 			usage();
631 		g_gate_load_module();
632 		g_gate_open_device();
633 		host = argv[0];
634 		path = argv[1];
635 		g_gatec_create();
636 		break;
637 	case DESTROY:
638 		if (unit == -1) {
639 			fprintf(stderr, "Required unit number.\n");
640 			usage();
641 		}
642 		g_gate_verbose = 1;
643 		g_gate_open_device();
644 		g_gate_destroy(unit, force);
645 		break;
646 	case LIST:
647 		g_gate_list(unit, g_gate_verbose);
648 		break;
649 	case RESCUE:
650 		if (argc != 2)
651 			usage();
652 		if (unit == -1) {
653 			fprintf(stderr, "Required unit number.\n");
654 			usage();
655 		}
656 		g_gate_open_device();
657 		host = argv[0];
658 		path = argv[1];
659 		g_gatec_rescue();
660 		break;
661 	case UNSET:
662 	default:
663 		usage();
664 	}
665 	g_gate_close_device();
666 	exit(EXIT_SUCCESS);
667 }
668