vfs_mount.c revision 54498 
1/*-
2 * Copyright (c) 1999 Michael Smith
3 * All rights reserved.
4 * Copyright (c) 1999 Poul-Henning Kamp
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 AUTHOR 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 AUTHOR 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: head/sys/kern/vfs_mount.c 54498 1999-12-12 16:34:43Z peter $
29 */
30
31/*
32 * Locate and mount the root filesystem.
33 *
34 * The root filesystem is detailed in the kernel environment variable
35 * vfs.root.mountfrom, which is expected to be in the general format
36 *
37 * <vfsname>:[<path>]
38 * vfsname   := the name of a VFS known to the kernel and capable
39 *              of being mounted as root
40 * path      := disk device name or other data used by the filesystem
41 *              to locate its physical store
42 *
43 */
44
45#include <sys/param.h>
46#include <sys/kernel.h>
47#include <sys/systm.h>
48#include <sys/proc.h>
49#include <sys/vnode.h>
50#include <sys/mount.h>
51#include <sys/malloc.h>
52#include <sys/reboot.h>
53#include <sys/diskslice.h>
54#include <sys/disklabel.h>
55#include <sys/conf.h>
56#include <sys/cons.h>
57
58MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
59
60#define ROOTNAME	"root_device"
61
62struct vnode	*rootvnode;
63
64/*
65 * The root specifiers we will try if RB_CDROM is specified.
66 */
67static char *cdrom_rootdevnames[] = {
68	"cd9660:cd0a",
69	"cd9660:acd0a",
70	"cd9660:wcd0a",
71	NULL
72};
73
74static void	vfs_mountroot(void *junk);
75static int	vfs_mountroot_try(char *mountfrom);
76static int	vfs_mountroot_ask(void);
77static void	gets(char *cp);
78
79/* legacy find-root code */
80char		*rootdevnames[2] = {NULL, NULL};
81static int	setrootbyname(char *name);
82
83SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
84
85/*
86 * Find and mount the root filesystem
87 */
88static void
89vfs_mountroot(void *junk)
90{
91	int		i;
92
93	/*
94	 * The root filesystem information is compiled in, and we are
95	 * booted with instructions to use it.
96	 */
97#ifdef ROOTDEVNAME
98	if ((boothowto & RB_DFLTROOT) &&
99	    !vfs_mountroot_try(ROOTDEVNAME))
100		return;
101#endif
102	/*
103	 * We are booted with instructions to prompt for the root filesystem,
104	 * or to use the compiled-in default when it doesn't exist.
105	 */
106	if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
107		if (!vfs_mountroot_ask())
108			return;
109	}
110
111	/*
112	 * We've been given the generic "use CDROM as root" flag.  This is
113	 * necessary because one media may be used in many different
114	 * devices, so we need to search for them.
115	 */
116	if (boothowto & RB_CDROM) {
117		for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
118			if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
119				return;
120		}
121	}
122
123	/*
124	 * Try to use the value read by the loader from /etc/fstab, or
125	 * supplied via some other means.  This is the preferred
126	 * mechanism.
127	 */
128	if (!vfs_mountroot_try(getenv("vfs.root.mountfrom")))
129		return;
130
131	/*
132	 * Try values that may have been computed by the machine-dependant
133	 * legacy code.
134	 */
135	if (!vfs_mountroot_try(rootdevnames[0]))
136		return;
137	if (!vfs_mountroot_try(rootdevnames[1]))
138		return;
139
140	/*
141	 * If we have a compiled-in default, and haven't already tried it, try
142	 * it now.
143	 */
144#ifdef ROOTDEVNAME
145	if (!(boothowto & RB_DFLTROOT))
146		if (!vfs_mountroot_try(ROOTDEVNAME))
147			return;
148#endif
149
150	/*
151	 * Everything so far has failed, prompt on the console if we haven't
152	 * already tried that.
153	 */
154	if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
155		return;
156	panic("Root mount failed, startup aborted.");
157}
158
159/*
160 * Mount (mountfrom) as the root filesystem.
161 */
162static int
163vfs_mountroot_try(char *mountfrom)
164{
165        struct mount	*mp;
166	char		*vfsname, *path;
167	int		error;
168	char		patt[32];
169	int		s;
170
171	vfsname = NULL;
172	path    = NULL;
173	mp      = NULL;
174	error   = EINVAL;
175
176	if (mountfrom == NULL)
177		return(error);		/* don't complain */
178
179	s = splcam();			/* Overkill, but annoying without it */
180	printf("Mounting root from %s\n", mountfrom);
181	splx(s);
182
183	/* parse vfs name and path */
184	vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
185	path = malloc(MNAMELEN, M_MOUNT, M_WAITOK);
186	vfsname[0] = path[0] = 0;
187	sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
188	if (sscanf(mountfrom, patt, vfsname, path) < 1)
189		goto done;
190
191	/* allocate a root mount */
192	error = vfs_rootmountalloc(vfsname, path[0] != 0 ? path : ROOTNAME,
193				   &mp);
194	if (error != 0) {
195		printf("Can't allocate root mount for filesystem '%s': %d\n",
196		       vfsname, error);
197		goto done;
198	}
199	mp->mnt_flag |= MNT_ROOTFS;
200
201	/* do our best to set rootdev */
202	if ((path[0] != 0) && setrootbyname(path))
203		printf("setrootbyname failed\n");
204
205	/* If the root device is a type "memory disk", mount RW */
206	if (rootdev != NODEV && devsw(rootdev) &&
207	    (devsw(rootdev)->d_flags & D_MEMDISK))
208		mp->mnt_flag &= ~MNT_RDONLY;
209
210	error = VFS_MOUNT(mp, NULL, NULL, NULL, curproc);
211
212done:
213	if (vfsname != NULL)
214		free(vfsname, M_MOUNT);
215	if (path != NULL)
216		free(path, M_MOUNT);
217	if (error != 0) {
218		if (mp != NULL) {
219			vfs_unbusy(mp, curproc);
220			free(mp, M_MOUNT);
221		}
222		printf("Root mount failed: %d\n", error);
223	} else {
224
225		/* register with list of mounted filesystems */
226		simple_lock(&mountlist_slock);
227		TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
228		simple_unlock(&mountlist_slock);
229
230		/* sanity check system clock against root filesystem timestamp */
231		inittodr(mp->mnt_time);
232		vfs_unbusy(mp, curproc);
233	}
234	return(error);
235}
236
237/*
238 * Spin prompting on the console for a suitable root filesystem
239 */
240static int
241vfs_mountroot_ask(void)
242{
243	char name[128];
244	int i;
245	dev_t dev;
246
247	for(;;) {
248		printf("\nManual root filesystem specification:\n");
249		printf("  <fstype>:<device>  Mount <device> using filesystem <fstype>\n");
250		printf("                       eg. ufs:/dev/da0s1a\n");
251		printf("  ?                  List valid disk boot devices\n");
252		printf("  <empty line>       Abort manual input\n");
253		printf("\n>>> ");
254		gets(name);
255		if (name[0] == 0)
256			return(1);
257		if (name[0] == '?') {
258			printf("Possibly valid devices for 'ufs' root:\n");
259			for (i = 0; i < NUMCDEVSW; i++) {
260				dev = makedev(i, 0);
261				if (devsw(dev) != NULL)
262					printf(" \"%s\"", devsw(dev)->d_name);
263			}
264			printf("\n");
265			continue;
266		}
267		if (!vfs_mountroot_try(name))
268			return(0);
269	}
270}
271
272static void
273gets(char *cp)
274{
275	char *lp;
276	int c;
277
278	lp = cp;
279	for (;;) {
280		printf("%c", c = cngetc() & 0177);
281		switch (c) {
282		case -1:
283		case '\n':
284		case '\r':
285			*lp++ = '\0';
286			return;
287		case '\b':
288		case '\177':
289			if (lp > cp) {
290				printf(" \b");
291				lp--;
292			}
293			continue;
294		case '#':
295			lp--;
296			if (lp < cp)
297				lp = cp;
298			continue;
299		case '@':
300		case 'u' & 037:
301			lp = cp;
302			printf("%c", '\n');
303			continue;
304		default:
305			*lp++ = c;
306		}
307	}
308}
309
310/*
311 * Set rootdev to match (name), given that we expect it to
312 * refer to a disk-like device.
313 */
314static int
315setrootbyname(char *name)
316{
317	char *cp;
318	int cd, unit, slice, part;
319	dev_t dev;
320
321	slice = 0;
322	part = 0;
323	cp = rindex(name, '/');
324	if (cp != NULL) {
325		name = cp + 1;
326	}
327	cp = name;
328	while (cp != '\0' && (*cp < '0' || *cp > '9'))
329		cp++;
330	if (cp == name) {
331		printf("missing device name\n");
332		return(1);
333	}
334	if (*cp == '\0') {
335		printf("missing unit number\n");
336		return(1);
337	}
338	unit = *cp - '0';
339	*cp++ = '\0';
340	for (cd = 0; cd < NUMCDEVSW; cd++) {
341		dev = makedev(cd, 0);
342		if (devsw(dev) != NULL &&
343		    strcmp(devsw(dev)->d_name, name) == 0)
344			goto gotit;
345	}
346	printf("no such device '%s'\n", name);
347	return (2);
348gotit:
349	while (*cp >= '0' && *cp <= '9')
350		unit += 10 * unit + *cp++ - '0';
351	if (*cp == 's' && cp[1] >= '0' && cp[1] <= '9') {
352		slice = cp[1] - '0' + 1;
353		cp += 2;
354	}
355	if (*cp >= 'a' && *cp <= 'h') {
356		part = *cp - 'a';
357		cp++;
358	}
359	if (*cp != '\0') {
360		printf("junk after name\n");
361		return (1);
362	}
363	rootdev = makedev(cd, dkmakeminor(unit, slice, part));
364	return 0;
365}
366
367