vfs_mount.c revision 75858 
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 75858 2001-04-23 09:05:15Z grog $
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
47#include <sys/param.h>
48#include <sys/kernel.h>
49#include <sys/systm.h>
50#include <sys/vnode.h>
51#include <net/radix.h>
52#include <sys/socket.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#include <paths.h>
61
62#include "opt_ddb.h"
63#ifdef DDB
64#include <ddb/ddb.h>
65#endif
66
67MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
68
69#define ROOTNAME	"root_device"
70
71struct vnode	*rootvnode;
72
73/*
74 * The root specifiers we will try if RB_CDROM is specified.
75 */
76static char *cdrom_rootdevnames[] = {
77	"cd9660:cd0a",
78	"cd9660:acd0a",
79	"cd9660:wcd0a",
80	NULL
81};
82
83static void	vfs_mountroot(void *junk);
84static int	vfs_mountroot_try(char *mountfrom);
85static int	vfs_mountroot_ask(void);
86static void	gets(char *cp);
87
88/* legacy find-root code */
89char		*rootdevnames[2] = {NULL, NULL};
90static int	setrootbyname(char *name);
91
92SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
93
94/*
95 * Find and mount the root filesystem
96 */
97static void
98vfs_mountroot(void *junk)
99{
100	int		i;
101
102	/*
103	 * The root filesystem information is compiled in, and we are
104	 * booted with instructions to use it.
105	 */
106#ifdef ROOTDEVNAME
107	if ((boothowto & RB_DFLTROOT) &&
108	    !vfs_mountroot_try(ROOTDEVNAME))
109		return;
110#endif
111	/*
112	 * We are booted with instructions to prompt for the root filesystem,
113	 * or to use the compiled-in default when it doesn't exist.
114	 */
115	if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
116		if (!vfs_mountroot_ask())
117			return;
118	}
119
120	/*
121	 * We've been given the generic "use CDROM as root" flag.  This is
122	 * necessary because one media may be used in many different
123	 * devices, so we need to search for them.
124	 */
125	if (boothowto & RB_CDROM) {
126		for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
127			if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
128				return;
129		}
130	}
131
132	/*
133	 * Try to use the value read by the loader from /etc/fstab, or
134	 * supplied via some other means.  This is the preferred
135	 * mechanism.
136	 */
137	if (!vfs_mountroot_try(getenv("vfs.root.mountfrom")))
138		return;
139
140	/*
141	 * Try values that may have been computed by the machine-dependant
142	 * legacy code.
143	 */
144	if (!vfs_mountroot_try(rootdevnames[0]))
145		return;
146	if (!vfs_mountroot_try(rootdevnames[1]))
147		return;
148
149	/*
150	 * If we have a compiled-in default, and haven't already tried it, try
151	 * it now.
152	 */
153#ifdef ROOTDEVNAME
154	if (!(boothowto & RB_DFLTROOT))
155		if (!vfs_mountroot_try(ROOTDEVNAME))
156			return;
157#endif
158
159	/*
160	 * Everything so far has failed, prompt on the console if we haven't
161	 * already tried that.
162	 */
163	if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
164		return;
165	panic("Root mount failed, startup aborted.");
166}
167
168/*
169 * Mount (mountfrom) as the root filesystem.
170 */
171static int
172vfs_mountroot_try(char *mountfrom)
173{
174        struct mount	*mp;
175	char		*vfsname, *path;
176	int		error;
177	char		patt[32];
178	int		s;
179
180	vfsname = NULL;
181	path    = NULL;
182	mp      = NULL;
183	error   = EINVAL;
184
185	if (mountfrom == NULL)
186		return(error);		/* don't complain */
187
188	s = splcam();			/* Overkill, but annoying without it */
189	printf("Mounting root from %s\n", mountfrom);
190	splx(s);
191
192	/* parse vfs name and path */
193	vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
194	path = malloc(MNAMELEN, M_MOUNT, M_WAITOK);
195	vfsname[0] = path[0] = 0;
196	sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
197	if (sscanf(mountfrom, patt, vfsname, path) < 1)
198		goto done;
199
200	/* allocate a root mount */
201	error = vfs_rootmountalloc(vfsname, path[0] != 0 ? path : ROOTNAME,
202				   &mp);
203	if (error != 0) {
204		printf("Can't allocate root mount for filesystem '%s': %d\n",
205		       vfsname, error);
206		goto done;
207	}
208	mp->mnt_flag |= MNT_ROOTFS;
209
210	/* do our best to set rootdev */
211	if ((path[0] != 0) && setrootbyname(path))
212		printf("setrootbyname failed\n");
213
214	/* If the root device is a type "memory disk", mount RW */
215	if (rootdev != NODEV && devsw(rootdev) &&
216	    (devsw(rootdev)->d_flags & D_MEMDISK))
217		mp->mnt_flag &= ~MNT_RDONLY;
218
219	/*
220	 * Set the mount path to be something useful, because the
221	 * filesystem code isn't responsible now for initialising
222	 * f_mntonname unless they want to override the default
223	 * (which is `path'.)
224	 */
225	strncpy(mp->mnt_stat.f_mntonname, "/", MNAMELEN);
226
227	error = VFS_MOUNT(mp, NULL, NULL, NULL, curproc);
228
229done:
230	if (vfsname != NULL)
231		free(vfsname, M_MOUNT);
232	if (path != NULL)
233		free(path, M_MOUNT);
234	if (error != 0) {
235		if (mp != NULL) {
236			vfs_unbusy(mp, curproc);
237			free(mp, M_MOUNT);
238		}
239		printf("Root mount failed: %d\n", error);
240	} else {
241
242		/* register with list of mounted filesystems */
243		mtx_lock(&mountlist_mtx);
244		TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
245		mtx_unlock(&mountlist_mtx);
246
247		/* sanity check system clock against root filesystem timestamp */
248		inittodr(mp->mnt_time);
249		vfs_unbusy(mp, curproc);
250	}
251	return(error);
252}
253
254/*
255 * Spin prompting on the console for a suitable root filesystem
256 */
257static int
258vfs_mountroot_ask(void)
259{
260	char name[128];
261	int i;
262	dev_t dev;
263
264	for(;;) {
265		printf("\nManual root filesystem specification:\n");
266		printf("  <fstype>:<device>  Mount <device> using filesystem <fstype>\n");
267		printf("                       eg. ufs:%sda0s1a\n", _PATH_DEV);
268		printf("  ?                  List valid disk boot devices\n");
269		printf("  <empty line>       Abort manual input\n");
270		printf("\nmountroot> ");
271		gets(name);
272		if (name[0] == 0)
273			return(1);
274		if (name[0] == '?') {
275			printf("Possibly valid devices for 'ufs' root:\n");
276			for (i = 0; i < NUMCDEVSW; i++) {
277				dev = makedev(i, 0);
278				if (devsw(dev) != NULL)
279					printf(" \"%s\"", devsw(dev)->d_name);
280			}
281			printf("\n");
282			continue;
283		}
284		if (!vfs_mountroot_try(name))
285			return(0);
286	}
287}
288
289static void
290gets(char *cp)
291{
292	char *lp;
293	int c;
294
295	lp = cp;
296	for (;;) {
297		printf("%c", c = cngetc() & 0177);
298		switch (c) {
299		case -1:
300		case '\n':
301		case '\r':
302			*lp++ = '\0';
303			return;
304		case '\b':
305		case '\177':
306			if (lp > cp) {
307				printf(" \b");
308				lp--;
309			}
310			continue;
311		case '#':
312			lp--;
313			if (lp < cp)
314				lp = cp;
315			continue;
316		case '@':
317		case 'u' & 037:
318			lp = cp;
319			printf("%c", '\n');
320			continue;
321		default:
322			*lp++ = c;
323		}
324	}
325}
326
327/*
328 * Convert a given name to the dev_t of the disk-like device
329 * it refers to.
330 */
331dev_t
332getdiskbyname(char *name) {
333	char *cp;
334	dev_t dev;
335
336	cp = name;
337	if (!bcmp(cp, "/dev/", 5))
338		cp += 5;
339
340	dev = NODEV;
341	EVENTHANDLER_INVOKE(dev_clone, cp, strlen(cp), &dev);
342	return (dev);
343}
344
345/*
346 * Set rootdev to match (name), given that we expect it to
347 * refer to a disk-like device.
348 */
349static int
350setrootbyname(char *name)
351{
352	dev_t diskdev;
353
354	diskdev = getdiskbyname(name);
355	if (diskdev != NODEV) {
356		rootdev = diskdev;
357		return (0);
358	}
359
360	return (1);
361}
362
363#ifdef DDB
364DB_SHOW_COMMAND(disk, db_getdiskbyname)
365{
366	dev_t dev;
367
368	if (modif[0] == '\0') {
369		db_error("usage: show disk/devicename");
370		return;
371	}
372	dev = getdiskbyname(modif);
373	if (dev != NODEV)
374		db_printf("dev_t = %p\n", dev);
375	else
376		db_printf("No disk device matched.\n");
377}
378#endif
379