xref: /freebsd/sys/kern/vfs_mountroot.c (revision 273c26a3c3bea87a241d6879abd4f991db180bf0)
1 /*-
2  * Copyright (c) 2010 Marcel Moolenaar
3  * Copyright (c) 1999-2004 Poul-Henning Kamp
4  * Copyright (c) 1999 Michael Smith
5  * Copyright (c) 1989, 1993
6  *      The Regents of the University of California.  All rights reserved.
7  * (c) UNIX System Laboratories, Inc.
8  * All or some portions of this file are derived from material licensed
9  * to the University of California by American Telephone and Telegraph
10  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
11  * the permission of UNIX System Laboratories, Inc.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  */
37 
38 #include "opt_rootdevname.h"
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include <sys/param.h>
44 #include <sys/conf.h>
45 #include <sys/cons.h>
46 #include <sys/fcntl.h>
47 #include <sys/jail.h>
48 #include <sys/kernel.h>
49 #include <sys/malloc.h>
50 #include <sys/mdioctl.h>
51 #include <sys/mount.h>
52 #include <sys/mutex.h>
53 #include <sys/namei.h>
54 #include <sys/priv.h>
55 #include <sys/proc.h>
56 #include <sys/filedesc.h>
57 #include <sys/reboot.h>
58 #include <sys/sbuf.h>
59 #include <sys/stat.h>
60 #include <sys/syscallsubr.h>
61 #include <sys/sysproto.h>
62 #include <sys/sx.h>
63 #include <sys/sysctl.h>
64 #include <sys/sysent.h>
65 #include <sys/systm.h>
66 #include <sys/vnode.h>
67 
68 #include <geom/geom.h>
69 
70 /*
71  * The root filesystem is detailed in the kernel environment variable
72  * vfs.root.mountfrom, which is expected to be in the general format
73  *
74  * <vfsname>:[<path>][	<vfsname>:[<path>] ...]
75  * vfsname   := the name of a VFS known to the kernel and capable
76  *              of being mounted as root
77  * path      := disk device name or other data used by the filesystem
78  *              to locate its physical store
79  *
80  * If the environment variable vfs.root.mountfrom is a space separated list,
81  * each list element is tried in turn and the root filesystem will be mounted
82  * from the first one that succeeds.
83  *
84  * The environment variable vfs.root.mountfrom.options is a comma delimited
85  * set of string mount options.  These mount options must be parseable
86  * by nmount() in the kernel.
87  */
88 
89 static int parse_mount(char **);
90 static struct mntarg *parse_mountroot_options(struct mntarg *, const char *);
91 static int sysctl_vfs_root_mount_hold(SYSCTL_HANDLER_ARGS);
92 static void vfs_mountroot_wait(void);
93 static int vfs_mountroot_wait_if_neccessary(const char *fs, const char *dev);
94 
95 /*
96  * The vnode of the system's root (/ in the filesystem, without chroot
97  * active.)
98  */
99 struct vnode *rootvnode;
100 
101 /*
102  * Mount of the system's /dev.
103  */
104 struct mount *rootdevmp;
105 
106 char *rootdevnames[2] = {NULL, NULL};
107 
108 struct mtx root_holds_mtx;
109 MTX_SYSINIT(root_holds, &root_holds_mtx, "root_holds", MTX_DEF);
110 
111 struct root_hold_token {
112 	const char			*who;
113 	LIST_ENTRY(root_hold_token)	list;
114 };
115 
116 static LIST_HEAD(, root_hold_token)	root_holds =
117     LIST_HEAD_INITIALIZER(root_holds);
118 
119 enum action {
120 	A_CONTINUE,
121 	A_PANIC,
122 	A_REBOOT,
123 	A_RETRY
124 };
125 
126 static enum action root_mount_onfail = A_CONTINUE;
127 
128 static int root_mount_mddev;
129 static int root_mount_complete;
130 
131 /* By default wait up to 3 seconds for devices to appear. */
132 static int root_mount_timeout = 3;
133 TUNABLE_INT("vfs.mountroot.timeout", &root_mount_timeout);
134 
135 SYSCTL_PROC(_vfs, OID_AUTO, root_mount_hold,
136     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
137     NULL, 0, sysctl_vfs_root_mount_hold, "A",
138     "List of root mount hold tokens");
139 
140 static int
141 sysctl_vfs_root_mount_hold(SYSCTL_HANDLER_ARGS)
142 {
143 	struct sbuf sb;
144 	struct root_hold_token *h;
145 	int error;
146 
147 	sbuf_new(&sb, NULL, 256, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
148 
149 	mtx_lock(&root_holds_mtx);
150 	LIST_FOREACH(h, &root_holds, list) {
151 		if (h != LIST_FIRST(&root_holds))
152 			sbuf_putc(&sb, ' ');
153 		sbuf_printf(&sb, "%s", h->who);
154 	}
155 	mtx_unlock(&root_holds_mtx);
156 
157 	error = sbuf_finish(&sb);
158 	if (error == 0)
159 		error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
160 	sbuf_delete(&sb);
161 	return (error);
162 }
163 
164 struct root_hold_token *
165 root_mount_hold(const char *identifier)
166 {
167 	struct root_hold_token *h;
168 
169 	if (root_mounted())
170 		return (NULL);
171 
172 	h = malloc(sizeof *h, M_DEVBUF, M_ZERO | M_WAITOK);
173 	h->who = identifier;
174 	mtx_lock(&root_holds_mtx);
175 	LIST_INSERT_HEAD(&root_holds, h, list);
176 	mtx_unlock(&root_holds_mtx);
177 	return (h);
178 }
179 
180 void
181 root_mount_rel(struct root_hold_token *h)
182 {
183 
184 	if (h == NULL)
185 		return;
186 	mtx_lock(&root_holds_mtx);
187 	LIST_REMOVE(h, list);
188 	wakeup(&root_holds);
189 	mtx_unlock(&root_holds_mtx);
190 	free(h, M_DEVBUF);
191 }
192 
193 int
194 root_mounted(void)
195 {
196 
197 	/* No mutex is acquired here because int stores are atomic. */
198 	return (root_mount_complete);
199 }
200 
201 static void
202 set_rootvnode(void)
203 {
204 	struct proc *p;
205 
206 	if (VFS_ROOT(TAILQ_FIRST(&mountlist), LK_EXCLUSIVE, &rootvnode))
207 		panic("Cannot find root vnode");
208 
209 	VOP_UNLOCK(rootvnode, 0);
210 
211 	p = curthread->td_proc;
212 	FILEDESC_XLOCK(p->p_fd);
213 
214 	if (p->p_fd->fd_cdir != NULL)
215 		vrele(p->p_fd->fd_cdir);
216 	p->p_fd->fd_cdir = rootvnode;
217 	VREF(rootvnode);
218 
219 	if (p->p_fd->fd_rdir != NULL)
220 		vrele(p->p_fd->fd_rdir);
221 	p->p_fd->fd_rdir = rootvnode;
222 	VREF(rootvnode);
223 
224 	FILEDESC_XUNLOCK(p->p_fd);
225 }
226 
227 static int
228 vfs_mountroot_devfs(struct thread *td, struct mount **mpp)
229 {
230 	struct vfsoptlist *opts;
231 	struct vfsconf *vfsp;
232 	struct mount *mp;
233 	int error;
234 
235 	*mpp = NULL;
236 
237 	if (rootdevmp != NULL) {
238 		/*
239 		 * Already have /dev; this happens during rerooting.
240 		 */
241 		error = vfs_busy(rootdevmp, 0);
242 		if (error != 0)
243 			return (error);
244 		*mpp = rootdevmp;
245 	} else {
246 		vfsp = vfs_byname("devfs");
247 		KASSERT(vfsp != NULL, ("Could not find devfs by name"));
248 		if (vfsp == NULL)
249 			return (ENOENT);
250 
251 		mp = vfs_mount_alloc(NULLVP, vfsp, "/dev", td->td_ucred);
252 
253 		error = VFS_MOUNT(mp);
254 		KASSERT(error == 0, ("VFS_MOUNT(devfs) failed %d", error));
255 		if (error)
256 			return (error);
257 
258 		opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
259 		TAILQ_INIT(opts);
260 		mp->mnt_opt = opts;
261 
262 		mtx_lock(&mountlist_mtx);
263 		TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
264 		mtx_unlock(&mountlist_mtx);
265 
266 		*mpp = mp;
267 		rootdevmp = mp;
268 	}
269 
270 	set_rootvnode();
271 
272 	error = kern_symlinkat(td, "/", AT_FDCWD, "dev", UIO_SYSSPACE);
273 	if (error)
274 		printf("kern_symlink /dev -> / returns %d\n", error);
275 
276 	return (error);
277 }
278 
279 static void
280 vfs_mountroot_shuffle(struct thread *td, struct mount *mpdevfs)
281 {
282 	struct nameidata nd;
283 	struct mount *mporoot, *mpnroot;
284 	struct vnode *vp, *vporoot, *vpdevfs;
285 	char *fspath;
286 	int error;
287 
288 	mpnroot = TAILQ_NEXT(mpdevfs, mnt_list);
289 
290 	/* Shuffle the mountlist. */
291 	mtx_lock(&mountlist_mtx);
292 	mporoot = TAILQ_FIRST(&mountlist);
293 	TAILQ_REMOVE(&mountlist, mpdevfs, mnt_list);
294 	if (mporoot != mpdevfs) {
295 		TAILQ_REMOVE(&mountlist, mpnroot, mnt_list);
296 		TAILQ_INSERT_HEAD(&mountlist, mpnroot, mnt_list);
297 	}
298 	TAILQ_INSERT_TAIL(&mountlist, mpdevfs, mnt_list);
299 	mtx_unlock(&mountlist_mtx);
300 
301 	cache_purgevfs(mporoot);
302 	if (mporoot != mpdevfs)
303 		cache_purgevfs(mpdevfs);
304 
305 	VFS_ROOT(mporoot, LK_EXCLUSIVE, &vporoot);
306 
307 	VI_LOCK(vporoot);
308 	vporoot->v_iflag &= ~VI_MOUNT;
309 	VI_UNLOCK(vporoot);
310 	vporoot->v_mountedhere = NULL;
311 	mporoot->mnt_flag &= ~MNT_ROOTFS;
312 	mporoot->mnt_vnodecovered = NULL;
313 	vput(vporoot);
314 
315 	/* Set up the new rootvnode, and purge the cache */
316 	mpnroot->mnt_vnodecovered = NULL;
317 	set_rootvnode();
318 	cache_purgevfs(rootvnode->v_mount);
319 
320 	if (mporoot != mpdevfs) {
321 		/* Remount old root under /.mount or /mnt */
322 		fspath = "/.mount";
323 		NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
324 		    fspath, td);
325 		error = namei(&nd);
326 		if (error) {
327 			NDFREE(&nd, NDF_ONLY_PNBUF);
328 			fspath = "/mnt";
329 			NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
330 			    fspath, td);
331 			error = namei(&nd);
332 		}
333 		if (!error) {
334 			vp = nd.ni_vp;
335 			error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
336 			if (!error)
337 				error = vinvalbuf(vp, V_SAVE, 0, 0);
338 			if (!error) {
339 				cache_purge(vp);
340 				mporoot->mnt_vnodecovered = vp;
341 				vp->v_mountedhere = mporoot;
342 				strlcpy(mporoot->mnt_stat.f_mntonname,
343 				    fspath, MNAMELEN);
344 				VOP_UNLOCK(vp, 0);
345 			} else
346 				vput(vp);
347 		}
348 		NDFREE(&nd, NDF_ONLY_PNBUF);
349 
350 		if (error)
351 			printf("mountroot: unable to remount previous root "
352 			    "under /.mount or /mnt (error %d)\n", error);
353 	}
354 
355 	/* Remount devfs under /dev */
356 	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, "/dev", td);
357 	error = namei(&nd);
358 	if (!error) {
359 		vp = nd.ni_vp;
360 		error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
361 		if (!error)
362 			error = vinvalbuf(vp, V_SAVE, 0, 0);
363 		if (!error) {
364 			vpdevfs = mpdevfs->mnt_vnodecovered;
365 			if (vpdevfs != NULL) {
366 				cache_purge(vpdevfs);
367 				vpdevfs->v_mountedhere = NULL;
368 				vrele(vpdevfs);
369 			}
370 			mpdevfs->mnt_vnodecovered = vp;
371 			vp->v_mountedhere = mpdevfs;
372 			VOP_UNLOCK(vp, 0);
373 		} else
374 			vput(vp);
375 	}
376 	if (error)
377 		printf("mountroot: unable to remount devfs under /dev "
378 		    "(error %d)\n", error);
379 	NDFREE(&nd, NDF_ONLY_PNBUF);
380 
381 	if (mporoot == mpdevfs) {
382 		vfs_unbusy(mpdevfs);
383 		/* Unlink the no longer needed /dev/dev -> / symlink */
384 		error = kern_unlinkat(td, AT_FDCWD, "/dev/dev",
385 		    UIO_SYSSPACE, 0);
386 		if (error)
387 			printf("mountroot: unable to unlink /dev/dev "
388 			    "(error %d)\n", error);
389 	}
390 }
391 
392 /*
393  * Configuration parser.
394  */
395 
396 /* Parser character classes. */
397 #define	CC_WHITESPACE		-1
398 #define	CC_NONWHITESPACE	-2
399 
400 /* Parse errors. */
401 #define	PE_EOF			-1
402 #define	PE_EOL			-2
403 
404 static __inline int
405 parse_peek(char **conf)
406 {
407 
408 	return (**conf);
409 }
410 
411 static __inline void
412 parse_poke(char **conf, int c)
413 {
414 
415 	**conf = c;
416 }
417 
418 static __inline void
419 parse_advance(char **conf)
420 {
421 
422 	(*conf)++;
423 }
424 
425 static int
426 parse_skipto(char **conf, int mc)
427 {
428 	int c, match;
429 
430 	while (1) {
431 		c = parse_peek(conf);
432 		if (c == 0)
433 			return (PE_EOF);
434 		switch (mc) {
435 		case CC_WHITESPACE:
436 			match = (c == ' ' || c == '\t' || c == '\n') ? 1 : 0;
437 			break;
438 		case CC_NONWHITESPACE:
439 			if (c == '\n')
440 				return (PE_EOL);
441 			match = (c != ' ' && c != '\t') ? 1 : 0;
442 			break;
443 		default:
444 			match = (c == mc) ? 1 : 0;
445 			break;
446 		}
447 		if (match)
448 			break;
449 		parse_advance(conf);
450 	}
451 	return (0);
452 }
453 
454 static int
455 parse_token(char **conf, char **tok)
456 {
457 	char *p;
458 	size_t len;
459 	int error;
460 
461 	*tok = NULL;
462 	error = parse_skipto(conf, CC_NONWHITESPACE);
463 	if (error)
464 		return (error);
465 	p = *conf;
466 	error = parse_skipto(conf, CC_WHITESPACE);
467 	len = *conf - p;
468 	*tok = malloc(len + 1, M_TEMP, M_WAITOK | M_ZERO);
469 	bcopy(p, *tok, len);
470 	return (0);
471 }
472 
473 static void
474 parse_dir_ask_printenv(const char *var)
475 {
476 	char *val;
477 
478 	val = kern_getenv(var);
479 	if (val != NULL) {
480 		printf("  %s=%s\n", var, val);
481 		freeenv(val);
482 	}
483 }
484 
485 static int
486 parse_dir_ask(char **conf)
487 {
488 	char name[80];
489 	char *mnt;
490 	int error;
491 
492 	vfs_mountroot_wait();
493 
494 	printf("\nLoader variables:\n");
495 	parse_dir_ask_printenv("vfs.root.mountfrom");
496 	parse_dir_ask_printenv("vfs.root.mountfrom.options");
497 
498 	printf("\nManual root filesystem specification:\n");
499 	printf("  <fstype>:<device> [options]\n");
500 	printf("      Mount <device> using filesystem <fstype>\n");
501 	printf("      and with the specified (optional) option list.\n");
502 	printf("\n");
503 	printf("    eg. ufs:/dev/da0s1a\n");
504 	printf("        zfs:tank\n");
505 	printf("        cd9660:/dev/cd0 ro\n");
506 	printf("          (which is equivalent to: ");
507 	printf("mount -t cd9660 -o ro /dev/cd0 /)\n");
508 	printf("\n");
509 	printf("  ?               List valid disk boot devices\n");
510 	printf("  .               Yield 1 second (for background tasks)\n");
511 	printf("  <empty line>    Abort manual input\n");
512 
513 	do {
514 		error = EINVAL;
515 		printf("\nmountroot> ");
516 		cngets(name, sizeof(name), GETS_ECHO);
517 		if (name[0] == '\0')
518 			break;
519 		if (name[0] == '?' && name[1] == '\0') {
520 			printf("\nList of GEOM managed disk devices:\n  ");
521 			g_dev_print();
522 			continue;
523 		}
524 		if (name[0] == '.' && name[1] == '\0') {
525 			pause("rmask", hz);
526 			continue;
527 		}
528 		mnt = name;
529 		error = parse_mount(&mnt);
530 		if (error == -1)
531 			printf("Invalid file system specification.\n");
532 	} while (error != 0);
533 
534 	return (error);
535 }
536 
537 static int
538 parse_dir_md(char **conf)
539 {
540 	struct stat sb;
541 	struct thread *td;
542 	struct md_ioctl *mdio;
543 	char *path, *tok;
544 	int error, fd, len;
545 
546 	td = curthread;
547 
548 	error = parse_token(conf, &tok);
549 	if (error)
550 		return (error);
551 
552 	len = strlen(tok);
553 	mdio = malloc(sizeof(*mdio) + len + 1, M_TEMP, M_WAITOK | M_ZERO);
554 	path = (void *)(mdio + 1);
555 	bcopy(tok, path, len);
556 	free(tok, M_TEMP);
557 
558 	/* Get file status. */
559 	error = kern_statat(td, 0, AT_FDCWD, path, UIO_SYSSPACE, &sb, NULL);
560 	if (error)
561 		goto out;
562 
563 	/* Open /dev/mdctl so that we can attach/detach. */
564 	error = kern_openat(td, AT_FDCWD, "/dev/" MDCTL_NAME, UIO_SYSSPACE,
565 	    O_RDWR, 0);
566 	if (error)
567 		goto out;
568 
569 	fd = td->td_retval[0];
570 	mdio->md_version = MDIOVERSION;
571 	mdio->md_type = MD_VNODE;
572 
573 	if (root_mount_mddev != -1) {
574 		mdio->md_unit = root_mount_mddev;
575 		DROP_GIANT();
576 		error = kern_ioctl(td, fd, MDIOCDETACH, (void *)mdio);
577 		PICKUP_GIANT();
578 		/* Ignore errors. We don't care. */
579 		root_mount_mddev = -1;
580 	}
581 
582 	mdio->md_file = (void *)(mdio + 1);
583 	mdio->md_options = MD_AUTOUNIT | MD_READONLY;
584 	mdio->md_mediasize = sb.st_size;
585 	mdio->md_unit = 0;
586 	DROP_GIANT();
587 	error = kern_ioctl(td, fd, MDIOCATTACH, (void *)mdio);
588 	PICKUP_GIANT();
589 	if (error)
590 		goto out;
591 
592 	if (mdio->md_unit > 9) {
593 		printf("rootmount: too many md units\n");
594 		mdio->md_file = NULL;
595 		mdio->md_options = 0;
596 		mdio->md_mediasize = 0;
597 		DROP_GIANT();
598 		error = kern_ioctl(td, fd, MDIOCDETACH, (void *)mdio);
599 		PICKUP_GIANT();
600 		/* Ignore errors. We don't care. */
601 		error = ERANGE;
602 		goto out;
603 	}
604 
605 	root_mount_mddev = mdio->md_unit;
606 	printf(MD_NAME "%u attached to %s\n", root_mount_mddev, mdio->md_file);
607 
608 	error = kern_close(td, fd);
609 
610  out:
611 	free(mdio, M_TEMP);
612 	return (error);
613 }
614 
615 static int
616 parse_dir_onfail(char **conf)
617 {
618 	char *action;
619 	int error;
620 
621 	error = parse_token(conf, &action);
622 	if (error)
623 		return (error);
624 
625 	if (!strcmp(action, "continue"))
626 		root_mount_onfail = A_CONTINUE;
627 	else if (!strcmp(action, "panic"))
628 		root_mount_onfail = A_PANIC;
629 	else if (!strcmp(action, "reboot"))
630 		root_mount_onfail = A_REBOOT;
631 	else if (!strcmp(action, "retry"))
632 		root_mount_onfail = A_RETRY;
633 	else {
634 		printf("rootmount: %s: unknown action\n", action);
635 		error = EINVAL;
636 	}
637 
638 	free(action, M_TEMP);
639 	return (0);
640 }
641 
642 static int
643 parse_dir_timeout(char **conf)
644 {
645 	char *tok, *endtok;
646 	long secs;
647 	int error;
648 
649 	error = parse_token(conf, &tok);
650 	if (error)
651 		return (error);
652 
653 	secs = strtol(tok, &endtok, 0);
654 	error = (secs < 0 || *endtok != '\0') ? EINVAL : 0;
655 	if (!error)
656 		root_mount_timeout = secs;
657 	free(tok, M_TEMP);
658 	return (error);
659 }
660 
661 static int
662 parse_directive(char **conf)
663 {
664 	char *dir;
665 	int error;
666 
667 	error = parse_token(conf, &dir);
668 	if (error)
669 		return (error);
670 
671 	if (strcmp(dir, ".ask") == 0)
672 		error = parse_dir_ask(conf);
673 	else if (strcmp(dir, ".md") == 0)
674 		error = parse_dir_md(conf);
675 	else if (strcmp(dir, ".onfail") == 0)
676 		error = parse_dir_onfail(conf);
677 	else if (strcmp(dir, ".timeout") == 0)
678 		error = parse_dir_timeout(conf);
679 	else {
680 		printf("mountroot: invalid directive `%s'\n", dir);
681 		/* Ignore the rest of the line. */
682 		(void)parse_skipto(conf, '\n');
683 		error = EINVAL;
684 	}
685 	free(dir, M_TEMP);
686 	return (error);
687 }
688 
689 static int
690 parse_mount_dev_present(const char *dev)
691 {
692 	struct nameidata nd;
693 	int error;
694 
695 	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, dev, curthread);
696 	error = namei(&nd);
697 	if (!error)
698 		vput(nd.ni_vp);
699 	NDFREE(&nd, NDF_ONLY_PNBUF);
700 	return (error != 0) ? 0 : 1;
701 }
702 
703 #define	ERRMSGL	255
704 static int
705 parse_mount(char **conf)
706 {
707 	char *errmsg;
708 	struct mntarg *ma;
709 	char *dev, *fs, *opts, *tok;
710 	int error;
711 
712 	error = parse_token(conf, &tok);
713 	if (error)
714 		return (error);
715 	fs = tok;
716 	error = parse_skipto(&tok, ':');
717 	if (error) {
718 		free(fs, M_TEMP);
719 		return (error);
720 	}
721 	parse_poke(&tok, '\0');
722 	parse_advance(&tok);
723 	dev = tok;
724 
725 	if (root_mount_mddev != -1) {
726 		/* Handle substitution for the md unit number. */
727 		tok = strstr(dev, "md#");
728 		if (tok != NULL)
729 			tok[2] = '0' + root_mount_mddev;
730 	}
731 
732 	/* Parse options. */
733 	error = parse_token(conf, &tok);
734 	opts = (error == 0) ? tok : NULL;
735 
736 	printf("Trying to mount root from %s:%s [%s]...\n", fs, dev,
737 	    (opts != NULL) ? opts : "");
738 
739 	errmsg = malloc(ERRMSGL, M_TEMP, M_WAITOK | M_ZERO);
740 
741 	if (vfs_byname(fs) == NULL) {
742 		strlcpy(errmsg, "unknown file system", ERRMSGL);
743 		error = ENOENT;
744 		goto out;
745 	}
746 
747 	error = vfs_mountroot_wait_if_neccessary(fs, dev);
748 	if (error != 0)
749 		goto out;
750 
751 	ma = NULL;
752 	ma = mount_arg(ma, "fstype", fs, -1);
753 	ma = mount_arg(ma, "fspath", "/", -1);
754 	ma = mount_arg(ma, "from", dev, -1);
755 	ma = mount_arg(ma, "errmsg", errmsg, ERRMSGL);
756 	ma = mount_arg(ma, "ro", NULL, 0);
757 	ma = parse_mountroot_options(ma, opts);
758 	error = kernel_mount(ma, MNT_ROOTFS);
759 
760  out:
761 	if (error) {
762 		printf("Mounting from %s:%s failed with error %d",
763 		    fs, dev, error);
764 		if (errmsg[0] != '\0')
765 			printf(": %s", errmsg);
766 		printf(".\n");
767 	}
768 	free(fs, M_TEMP);
769 	free(errmsg, M_TEMP);
770 	if (opts != NULL)
771 		free(opts, M_TEMP);
772 	/* kernel_mount can return -1 on error. */
773 	return ((error < 0) ? EDOOFUS : error);
774 }
775 #undef ERRMSGL
776 
777 static int
778 vfs_mountroot_parse(struct sbuf *sb, struct mount *mpdevfs)
779 {
780 	struct mount *mp;
781 	char *conf;
782 	int error;
783 
784 	root_mount_mddev = -1;
785 
786 retry:
787 	conf = sbuf_data(sb);
788 	mp = TAILQ_NEXT(mpdevfs, mnt_list);
789 	error = (mp == NULL) ? 0 : EDOOFUS;
790 	root_mount_onfail = A_CONTINUE;
791 	while (mp == NULL) {
792 		error = parse_skipto(&conf, CC_NONWHITESPACE);
793 		if (error == PE_EOL) {
794 			parse_advance(&conf);
795 			continue;
796 		}
797 		if (error < 0)
798 			break;
799 		switch (parse_peek(&conf)) {
800 		case '#':
801 			error = parse_skipto(&conf, '\n');
802 			break;
803 		case '.':
804 			error = parse_directive(&conf);
805 			break;
806 		default:
807 			error = parse_mount(&conf);
808 			if (error == -1) {
809 				printf("mountroot: invalid file system "
810 				    "specification.\n");
811 				error = 0;
812 			}
813 			break;
814 		}
815 		if (error < 0)
816 			break;
817 		/* Ignore any trailing garbage on the line. */
818 		if (parse_peek(&conf) != '\n') {
819 			printf("mountroot: advancing to next directive...\n");
820 			(void)parse_skipto(&conf, '\n');
821 		}
822 		mp = TAILQ_NEXT(mpdevfs, mnt_list);
823 	}
824 	if (mp != NULL)
825 		return (0);
826 
827 	/*
828 	 * We failed to mount (a new) root.
829 	 */
830 	switch (root_mount_onfail) {
831 	case A_CONTINUE:
832 		break;
833 	case A_PANIC:
834 		panic("mountroot: unable to (re-)mount root.");
835 		/* NOTREACHED */
836 	case A_RETRY:
837 		goto retry;
838 	case A_REBOOT:
839 		kern_reboot(RB_NOSYNC);
840 		/* NOTREACHED */
841 	}
842 
843 	return (error);
844 }
845 
846 static void
847 vfs_mountroot_conf0(struct sbuf *sb)
848 {
849 	char *s, *tok, *mnt, *opt;
850 	int error;
851 
852 	sbuf_printf(sb, ".onfail panic\n");
853 	sbuf_printf(sb, ".timeout %d\n", root_mount_timeout);
854 	if (boothowto & RB_ASKNAME)
855 		sbuf_printf(sb, ".ask\n");
856 #ifdef ROOTDEVNAME
857 	if (boothowto & RB_DFLTROOT)
858 		sbuf_printf(sb, "%s\n", ROOTDEVNAME);
859 #endif
860 	if (boothowto & RB_CDROM) {
861 		sbuf_printf(sb, "cd9660:/dev/cd0 ro\n");
862 		sbuf_printf(sb, ".timeout 0\n");
863 		sbuf_printf(sb, "cd9660:/dev/cd1 ro\n");
864 		sbuf_printf(sb, ".timeout %d\n", root_mount_timeout);
865 	}
866 	s = kern_getenv("vfs.root.mountfrom");
867 	if (s != NULL) {
868 		opt = kern_getenv("vfs.root.mountfrom.options");
869 		tok = s;
870 		error = parse_token(&tok, &mnt);
871 		while (!error) {
872 			sbuf_printf(sb, "%s %s\n", mnt,
873 			    (opt != NULL) ? opt : "");
874 			free(mnt, M_TEMP);
875 			error = parse_token(&tok, &mnt);
876 		}
877 		if (opt != NULL)
878 			freeenv(opt);
879 		freeenv(s);
880 	}
881 	if (rootdevnames[0] != NULL)
882 		sbuf_printf(sb, "%s\n", rootdevnames[0]);
883 	if (rootdevnames[1] != NULL)
884 		sbuf_printf(sb, "%s\n", rootdevnames[1]);
885 #ifdef ROOTDEVNAME
886 	if (!(boothowto & RB_DFLTROOT))
887 		sbuf_printf(sb, "%s\n", ROOTDEVNAME);
888 #endif
889 	if (!(boothowto & RB_ASKNAME))
890 		sbuf_printf(sb, ".ask\n");
891 }
892 
893 static int
894 vfs_mountroot_readconf(struct thread *td, struct sbuf *sb)
895 {
896 	static char buf[128];
897 	struct nameidata nd;
898 	off_t ofs;
899 	ssize_t resid;
900 	int error, flags, len;
901 
902 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/.mount.conf", td);
903 	flags = FREAD;
904 	error = vn_open(&nd, &flags, 0, NULL);
905 	if (error)
906 		return (error);
907 
908 	NDFREE(&nd, NDF_ONLY_PNBUF);
909 	ofs = 0;
910 	len = sizeof(buf) - 1;
911 	while (1) {
912 		error = vn_rdwr(UIO_READ, nd.ni_vp, buf, len, ofs,
913 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
914 		    NOCRED, &resid, td);
915 		if (error)
916 			break;
917 		if (resid == len)
918 			break;
919 		buf[len - resid] = 0;
920 		sbuf_printf(sb, "%s", buf);
921 		ofs += len - resid;
922 	}
923 
924 	VOP_UNLOCK(nd.ni_vp, 0);
925 	vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
926 	return (error);
927 }
928 
929 static void
930 vfs_mountroot_wait(void)
931 {
932 	struct root_hold_token *h;
933 	struct timeval lastfail;
934 	int curfail;
935 
936 	curfail = 0;
937 	while (1) {
938 		DROP_GIANT();
939 		g_waitidle();
940 		PICKUP_GIANT();
941 		mtx_lock(&root_holds_mtx);
942 		if (LIST_EMPTY(&root_holds)) {
943 			mtx_unlock(&root_holds_mtx);
944 			break;
945 		}
946 		if (ppsratecheck(&lastfail, &curfail, 1)) {
947 			printf("Root mount waiting for:");
948 			LIST_FOREACH(h, &root_holds, list)
949 				printf(" %s", h->who);
950 			printf("\n");
951 		}
952 		msleep(&root_holds, &root_holds_mtx, PZERO | PDROP, "roothold",
953 		    hz);
954 	}
955 }
956 
957 static int
958 vfs_mountroot_wait_if_neccessary(const char *fs, const char *dev)
959 {
960 	int delay, timeout;
961 
962 	/*
963 	 * In case of ZFS and NFS we don't have a way to wait for
964 	 * specific device.
965 	 */
966 	if (strcmp(fs, "zfs") == 0 || strstr(fs, "nfs") != NULL ||
967 	    dev[0] == '\0') {
968 		vfs_mountroot_wait();
969 		return (0);
970 	}
971 
972 	/*
973 	 * Otherwise, no point in waiting if the device is already there.
974 	 * Note that we must wait for GEOM to finish reconfiguring itself,
975 	 * eg for geom_part(4) to finish tasting.
976 	 */
977 	DROP_GIANT();
978 	g_waitidle();
979 	PICKUP_GIANT();
980 	if (parse_mount_dev_present(dev))
981 		return (0);
982 
983 	/*
984 	 * No luck.  Let's wait.  This code looks weird, but it's that way
985 	 * to behave exactly as it used to work before.
986 	 */
987 	vfs_mountroot_wait();
988 	printf("mountroot: waiting for device %s...\n", dev);
989 	delay = hz / 10;
990 	timeout = root_mount_timeout * hz;
991 	do {
992 		pause("rmdev", delay);
993 		timeout -= delay;
994 	} while (timeout > 0 && !parse_mount_dev_present(dev));
995 
996 	if (timeout <= 0)
997 		return (ENODEV);
998 
999 	return (0);
1000 }
1001 
1002 void
1003 vfs_mountroot(void)
1004 {
1005 	struct mount *mp;
1006 	struct sbuf *sb;
1007 	struct thread *td;
1008 	time_t timebase;
1009 	int error;
1010 
1011 	td = curthread;
1012 
1013 	sb = sbuf_new_auto();
1014 	vfs_mountroot_conf0(sb);
1015 	sbuf_finish(sb);
1016 
1017 	error = vfs_mountroot_devfs(td, &mp);
1018 	while (!error) {
1019 		error = vfs_mountroot_parse(sb, mp);
1020 		if (!error) {
1021 			vfs_mountroot_shuffle(td, mp);
1022 			sbuf_clear(sb);
1023 			error = vfs_mountroot_readconf(td, sb);
1024 			sbuf_finish(sb);
1025 		}
1026 	}
1027 
1028 	sbuf_delete(sb);
1029 
1030 	/*
1031 	 * Iterate over all currently mounted file systems and use
1032 	 * the time stamp found to check and/or initialize the RTC.
1033 	 * Call inittodr() only once and pass it the largest of the
1034 	 * timestamps we encounter.
1035 	 */
1036 	timebase = 0;
1037 	mtx_lock(&mountlist_mtx);
1038 	mp = TAILQ_FIRST(&mountlist);
1039 	while (mp != NULL) {
1040 		if (mp->mnt_time > timebase)
1041 			timebase = mp->mnt_time;
1042 		mp = TAILQ_NEXT(mp, mnt_list);
1043 	}
1044 	mtx_unlock(&mountlist_mtx);
1045 	inittodr(timebase);
1046 
1047 	/* Keep prison0's root in sync with the global rootvnode. */
1048 	mtx_lock(&prison0.pr_mtx);
1049 	prison0.pr_root = rootvnode;
1050 	vref(prison0.pr_root);
1051 	mtx_unlock(&prison0.pr_mtx);
1052 
1053 	mtx_lock(&root_holds_mtx);
1054 	atomic_store_rel_int(&root_mount_complete, 1);
1055 	wakeup(&root_mount_complete);
1056 	mtx_unlock(&root_holds_mtx);
1057 
1058 	EVENTHANDLER_INVOKE(mountroot);
1059 }
1060 
1061 static struct mntarg *
1062 parse_mountroot_options(struct mntarg *ma, const char *options)
1063 {
1064 	char *p;
1065 	char *name, *name_arg;
1066 	char *val, *val_arg;
1067 	char *opts;
1068 
1069 	if (options == NULL || options[0] == '\0')
1070 		return (ma);
1071 
1072 	p = opts = strdup(options, M_MOUNT);
1073 	if (opts == NULL) {
1074 		return (ma);
1075 	}
1076 
1077 	while((name = strsep(&p, ",")) != NULL) {
1078 		if (name[0] == '\0')
1079 			break;
1080 
1081 		val = strchr(name, '=');
1082 		if (val != NULL) {
1083 			*val = '\0';
1084 			++val;
1085 		}
1086 		if( strcmp(name, "rw") == 0 ||
1087 		    strcmp(name, "noro") == 0) {
1088 			/*
1089 			 * The first time we mount the root file system,
1090 			 * we need to mount 'ro', so We need to ignore
1091 			 * 'rw' and 'noro' mount options.
1092 			 */
1093 			continue;
1094 		}
1095 		name_arg = strdup(name, M_MOUNT);
1096 		val_arg = NULL;
1097 		if (val != NULL)
1098 			val_arg = strdup(val, M_MOUNT);
1099 
1100 		ma = mount_arg(ma, name_arg, val_arg,
1101 		    (val_arg != NULL ? -1 : 0));
1102 	}
1103 	free(opts, M_MOUNT);
1104 	return (ma);
1105 }
1106