vfs_mount.c revision 65051 
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 65051 2000-08-24 15:36:55Z phk $
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 "opt_rootdevname.h"
46#include "opt_devfs.h"
47
48#include <sys/param.h>
49#include <sys/kernel.h>
50#include <sys/systm.h>
51#include <sys/proc.h>
52#include <sys/vnode.h>
53#include <sys/mount.h>
54#include <sys/malloc.h>
55#include <sys/reboot.h>
56#include <sys/diskslice.h>
57#include <sys/disklabel.h>
58#include <sys/conf.h>
59#include <sys/cons.h>
60
61#include "opt_ddb.h"
62#ifdef DDB
63#include <ddb/ddb.h>
64#endif
65
66#ifdef DEVFS
67#include <sys/eventhandler.h>
68#include <fs/devfs/devfs.h>
69#endif
70
71MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
72
73#define ROOTNAME	"root_device"
74
75struct vnode	*rootvnode;
76
77/*
78 * The root specifiers we will try if RB_CDROM is specified.
79 */
80static char *cdrom_rootdevnames[] = {
81	"cd9660:cd0a",
82	"cd9660:acd0a",
83	"cd9660:wcd0a",
84	NULL
85};
86
87static void	vfs_mountroot(void *junk);
88static int	vfs_mountroot_try(char *mountfrom);
89static int	vfs_mountroot_ask(void);
90static void	gets(char *cp);
91
92/* legacy find-root code */
93char		*rootdevnames[2] = {NULL, NULL};
94static int	setrootbyname(char *name);
95
96SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
97
98/*
99 * Find and mount the root filesystem
100 */
101static void
102vfs_mountroot(void *junk)
103{
104	int		i;
105
106	/*
107	 * The root filesystem information is compiled in, and we are
108	 * booted with instructions to use it.
109	 */
110#ifdef ROOTDEVNAME
111	if ((boothowto & RB_DFLTROOT) &&
112	    !vfs_mountroot_try(ROOTDEVNAME))
113		return;
114#endif
115	/*
116	 * We are booted with instructions to prompt for the root filesystem,
117	 * or to use the compiled-in default when it doesn't exist.
118	 */
119	if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
120		if (!vfs_mountroot_ask())
121			return;
122	}
123
124	/*
125	 * We've been given the generic "use CDROM as root" flag.  This is
126	 * necessary because one media may be used in many different
127	 * devices, so we need to search for them.
128	 */
129	if (boothowto & RB_CDROM) {
130		for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
131			if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
132				return;
133		}
134	}
135
136	/*
137	 * Try to use the value read by the loader from /etc/fstab, or
138	 * supplied via some other means.  This is the preferred
139	 * mechanism.
140	 */
141	if (!vfs_mountroot_try(getenv("vfs.root.mountfrom")))
142		return;
143
144	/*
145	 * Try values that may have been computed by the machine-dependant
146	 * legacy code.
147	 */
148	if (!vfs_mountroot_try(rootdevnames[0]))
149		return;
150	if (!vfs_mountroot_try(rootdevnames[1]))
151		return;
152
153	/*
154	 * If we have a compiled-in default, and haven't already tried it, try
155	 * it now.
156	 */
157#ifdef ROOTDEVNAME
158	if (!(boothowto & RB_DFLTROOT))
159		if (!vfs_mountroot_try(ROOTDEVNAME))
160			return;
161#endif
162
163	/*
164	 * Everything so far has failed, prompt on the console if we haven't
165	 * already tried that.
166	 */
167	if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
168		return;
169	panic("Root mount failed, startup aborted.");
170}
171
172/*
173 * Mount (mountfrom) as the root filesystem.
174 */
175static int
176vfs_mountroot_try(char *mountfrom)
177{
178        struct mount	*mp;
179	char		*vfsname, *path;
180	int		error;
181	char		patt[32];
182	int		s;
183
184	vfsname = NULL;
185	path    = NULL;
186	mp      = NULL;
187	error   = EINVAL;
188
189	if (mountfrom == NULL)
190		return(error);		/* don't complain */
191
192	s = splcam();			/* Overkill, but annoying without it */
193	printf("Mounting root from %s\n", mountfrom);
194	splx(s);
195
196	/* parse vfs name and path */
197	vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
198	path = malloc(MNAMELEN, M_MOUNT, M_WAITOK);
199	vfsname[0] = path[0] = 0;
200	sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
201	if (sscanf(mountfrom, patt, vfsname, path) < 1)
202		goto done;
203
204	/* allocate a root mount */
205	error = vfs_rootmountalloc(vfsname, path[0] != 0 ? path : ROOTNAME,
206				   &mp);
207	if (error != 0) {
208		printf("Can't allocate root mount for filesystem '%s': %d\n",
209		       vfsname, error);
210		goto done;
211	}
212	mp->mnt_flag |= MNT_ROOTFS;
213
214	/* do our best to set rootdev */
215	if ((path[0] != 0) && setrootbyname(path))
216		printf("setrootbyname failed\n");
217
218	/* If the root device is a type "memory disk", mount RW */
219	if (rootdev != NODEV && devsw(rootdev) &&
220	    (devsw(rootdev)->d_flags & D_MEMDISK))
221		mp->mnt_flag &= ~MNT_RDONLY;
222
223	error = VFS_MOUNT(mp, NULL, NULL, NULL, curproc);
224
225done:
226	if (vfsname != NULL)
227		free(vfsname, M_MOUNT);
228	if (path != NULL)
229		free(path, M_MOUNT);
230	if (error != 0) {
231		if (mp != NULL) {
232			vfs_unbusy(mp, curproc);
233			free(mp, M_MOUNT);
234		}
235		printf("Root mount failed: %d\n", error);
236	} else {
237
238		/* register with list of mounted filesystems */
239		simple_lock(&mountlist_slock);
240		TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
241		simple_unlock(&mountlist_slock);
242
243		/* sanity check system clock against root filesystem timestamp */
244		inittodr(mp->mnt_time);
245		vfs_unbusy(mp, curproc);
246	}
247	return(error);
248}
249
250/*
251 * Spin prompting on the console for a suitable root filesystem
252 */
253static int
254vfs_mountroot_ask(void)
255{
256	char name[128];
257	int i;
258	dev_t dev;
259
260	for(;;) {
261		printf("\nManual root filesystem specification:\n");
262		printf("  <fstype>:<device>  Mount <device> using filesystem <fstype>\n");
263		printf("                       eg. ufs:/dev/da0s1a\n");
264		printf("  ?                  List valid disk boot devices\n");
265		printf("  <empty line>       Abort manual input\n");
266		printf("\nmountroot> ");
267		gets(name);
268		if (name[0] == 0)
269			return(1);
270		if (name[0] == '?') {
271			printf("Possibly valid devices for 'ufs' root:\n");
272			for (i = 0; i < NUMCDEVSW; i++) {
273				dev = makedev(i, 0);
274				if (devsw(dev) != NULL)
275					printf(" \"%s\"", devsw(dev)->d_name);
276			}
277			printf("\n");
278			continue;
279		}
280		if (!vfs_mountroot_try(name))
281			return(0);
282	}
283}
284
285static void
286gets(char *cp)
287{
288	char *lp;
289	int c;
290
291	lp = cp;
292	for (;;) {
293		printf("%c", c = cngetc() & 0177);
294		switch (c) {
295		case -1:
296		case '\n':
297		case '\r':
298			*lp++ = '\0';
299			return;
300		case '\b':
301		case '\177':
302			if (lp > cp) {
303				printf(" \b");
304				lp--;
305			}
306			continue;
307		case '#':
308			lp--;
309			if (lp < cp)
310				lp = cp;
311			continue;
312		case '@':
313		case 'u' & 037:
314			lp = cp;
315			printf("%c", '\n');
316			continue;
317		default:
318			*lp++ = c;
319		}
320	}
321}
322
323/*
324 * Convert a given name to the dev_t of the disk-like device
325 * it refers to.
326 */
327dev_t
328getdiskbyname(char *name) {
329#ifdef DEVFS
330	char *cp;
331	dev_t dev;
332
333	cp = name;
334	if (!bcmp(cp, "/dev/", 5))
335		cp += 5;
336
337	dev = NODEV;
338	EVENTHANDLER_INVOKE(devfs_clone, cp, strlen(cp), &dev);
339	return (dev);
340
341#else
342	char *cp;
343	int cd, unit, slice, part;
344	dev_t dev;
345
346	slice = 0;
347	part = 0;
348	cp = rindex(name, '/');
349	if (cp != NULL) {
350		name = cp + 1;
351	}
352	cp = name;
353	while (cp != '\0' && (*cp < '0' || *cp > '9'))
354		cp++;
355	if (cp == name) {
356		printf("missing device name\n");
357		return (NODEV);
358	}
359	if (*cp == '\0') {
360		printf("missing unit number\n");
361		return (NODEV);
362	}
363	unit = *cp - '0';
364	*cp++ = '\0';
365	for (cd = 0; cd < NUMCDEVSW; cd++) {
366		dev = makedev(cd, 0);
367		if (devsw(dev) != NULL &&
368		    strcmp(devsw(dev)->d_name, name) == 0)
369			goto gotit;
370	}
371	printf("no such device '%s'\n", name);
372	return (NODEV);
373gotit:
374	while (*cp >= '0' && *cp <= '9')
375		unit += 10 * unit + *cp++ - '0';
376	if (*cp == 's' && cp[1] >= '0' && cp[1] <= '9') {
377		slice = cp[1] - '0' + 1;
378		cp += 2;
379	}
380	if (*cp >= 'a' && *cp <= 'h') {
381		part = *cp - 'a';
382		cp++;
383	}
384	if (*cp != '\0') {
385		printf("junk after name\n");
386		return (NODEV);
387	}
388	return (makedev(cd, dkmakeminor(unit, slice, part)));
389#endif
390}
391
392/*
393 * Set rootdev to match (name), given that we expect it to
394 * refer to a disk-like device.
395 */
396static int
397setrootbyname(char *name)
398{
399	dev_t diskdev;
400
401	diskdev = getdiskbyname(name);
402	if (diskdev != NODEV) {
403		rootdev = diskdev;
404		return (0);
405	}
406
407	return (1);
408}
409
410#ifdef DDB
411DB_SHOW_COMMAND(disk, db_getdiskbyname)
412{
413	dev_t dev;
414
415	if (modif[0] == '\0') {
416		db_error("usage: show disk/devicename");
417		return;
418	}
419	dev = getdiskbyname(modif);
420	if (dev != NODEV)
421		db_printf("dev_t = %p\n", dev);
422	else
423		db_printf("No disk device matched.\n");
424}
425#endif
426