2 * Copyright (c) 1999 Michael Smith
4 * Copyright (c) 1999 Poul-Henning Kamp
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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.
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
28 * $FreeBSD: src/sys/kern/vfs_conf.c,v 1.49.2.5 2003/01/07 11:56:53 joerg Exp $
32 * Locate and mount the root filesystem.
34 * The root filesystem is detailed in the kernel environment variable
35 * vfs.root.mountfrom, which is expected to be in the general format
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
45 #include "opt_rootdevname.h"
47 #include <sys/param.h>
48 #include <sys/kernel.h>
49 #include <sys/systm.h>
51 #include <sys/vnode.h>
52 #include <sys/mount.h>
53 #include <sys/malloc.h>
54 #include <sys/reboot.h>
55 #include <sys/diskslice.h>
56 #include <sys/disklabel.h>
66 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
68 #define ROOTNAME "root_device"
70 struct vnode *rootvnode;
73 * The root specifiers we will try if RB_CDROM is specified.
75 static char *cdrom_rootdevnames[] = {
82 static void vfs_mountroot(void *junk);
83 static int vfs_mountroot_try(char *mountfrom);
84 static int vfs_mountroot_ask(void);
85 static void gets(char *cp);
87 /* legacy find-root code */
88 char *rootdevnames[2] = {NULL, NULL};
89 static int setrootbyname(char *name);
91 SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
94 * Find and mount the root filesystem
97 vfs_mountroot(void *junk)
102 * The root filesystem information is compiled in, and we are
103 * booted with instructions to use it.
106 if ((boothowto & RB_DFLTROOT) &&
107 !vfs_mountroot_try(ROOTDEVNAME))
111 * We are booted with instructions to prompt for the root filesystem,
112 * or to use the compiled-in default when it doesn't exist.
114 if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
115 if (!vfs_mountroot_ask())
120 * We've been given the generic "use CDROM as root" flag. This is
121 * necessary because one media may be used in many different
122 * devices, so we need to search for them.
124 if (boothowto & RB_CDROM) {
125 for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
126 if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
132 * Try to use the value read by the loader from /etc/fstab, or
133 * supplied via some other means. This is the preferred
136 if (!vfs_mountroot_try(getenv("vfs.root.mountfrom")))
140 * Try values that may have been computed by the machine-dependant
143 if (!vfs_mountroot_try(rootdevnames[0]))
145 if (!vfs_mountroot_try(rootdevnames[1]))
149 * If we have a compiled-in default, and haven't already tried it, try
153 if (!(boothowto & RB_DFLTROOT))
154 if (!vfs_mountroot_try(ROOTDEVNAME))
159 * Everything so far has failed, prompt on the console if we haven't
160 * already tried that.
162 if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
164 panic("Root mount failed, startup aborted.");
168 * Mount (mountfrom) as the root filesystem.
171 vfs_mountroot_try(char *mountfrom)
174 char *vfsname, *path;
184 if (mountfrom == NULL)
185 return(error); /* don't complain */
187 s = splcam(); /* Overkill, but annoying without it */
188 printf("Mounting root from %s\n", mountfrom);
191 /* parse vfs name and path */
192 vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
193 path = malloc(MNAMELEN, M_MOUNT, M_WAITOK);
194 vfsname[0] = path[0] = 0;
195 sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
196 if (sscanf(mountfrom, patt, vfsname, path) < 1)
199 /* allocate a root mount */
200 error = vfs_rootmountalloc(vfsname, path[0] != 0 ? path : ROOTNAME,
203 printf("Can't allocate root mount for filesystem '%s': %d\n",
207 mp->mnt_flag |= MNT_ROOTFS;
209 /* do our best to set rootdev */
210 if ((path[0] != 0) && setrootbyname(path))
211 printf("setrootbyname failed\n");
213 /* If the root device is a type "memory disk", mount RW */
214 if (rootdev != NODEV && devsw(rootdev) &&
215 (devsw(rootdev)->d_flags & D_MEMDISK))
216 mp->mnt_flag &= ~MNT_RDONLY;
218 error = VFS_MOUNT(mp, NULL, NULL, NULL, curproc);
222 free(vfsname, M_MOUNT);
227 vfs_unbusy(mp, curproc);
230 printf("Root mount failed: %d\n", error);
233 /* register with list of mounted filesystems */
234 simple_lock(&mountlist_slock);
235 TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
236 simple_unlock(&mountlist_slock);
238 /* sanity check system clock against root filesystem timestamp */
239 inittodr(mp->mnt_time);
240 vfs_unbusy(mp, curproc);
246 * Spin prompting on the console for a suitable root filesystem
249 vfs_mountroot_ask(void)
256 printf("\nManual root filesystem specification:\n");
257 printf(" <fstype>:<device> Mount <device> using filesystem <fstype>\n");
258 printf(" eg. ufs:%sda0s1a\n", _PATH_DEV);
259 printf(" ? List valid disk boot devices\n");
260 printf(" <empty line> Abort manual input\n");
261 printf("\nmountroot> ");
265 if (name[0] == '?') {
266 printf("Possibly valid devices for 'ufs' root:\n");
267 for (i = 0; i < NUMCDEVSW; i++) {
269 if (devsw(dev) != NULL)
270 printf(" \"%s\"", devsw(dev)->d_name);
275 if (!vfs_mountroot_try(name))
288 printf("%c", c = cngetc() & 0177);
319 * Convert a given name to the dev_t of the disk-like device
323 getdiskbyname(char *name) {
325 int cd, unit, slice, part;
330 if (strncmp(name, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
331 name += sizeof(_PATH_DEV) - 1;
333 while (*cp != '\0' && (*cp < '0' || *cp > '9') && *cp != '/')
336 printf("missing device name\n");
339 if (*cp == '\0' || *cp == '/')
344 for (cd = 0; cd < NUMCDEVSW; cd++) {
345 dev = makedev(cd, 0);
346 if (devsw(dev) != NULL &&
347 strcmp(devsw(dev)->d_name, name) == 0)
350 printf("no such device '%s'\n", name);
353 if (devsw(dev)->d_maj == major(rootdev))
354 /* driver has already configured rootdev, e. g. vinum */
357 printf("missing unit number\n");
360 while (*cp >= '0' && *cp <= '9')
361 unit = 10 * unit + *cp++ - '0';
362 if (*cp == 's' && cp[1] >= '0' && cp[1] <= '9') {
363 slice = cp[1] - '0' + 1;
366 if (*cp >= 'a' && *cp <= 'h') {
371 printf("junk after name\n");
374 return (makedev(cd, dkmakeminor(unit, slice, part)));
378 * Set rootdev to match (name), given that we expect it to
379 * refer to a disk-like device.
382 setrootbyname(char *name)
386 diskdev = getdiskbyname(name);
387 if (diskdev != NODEV) {
396 DB_SHOW_COMMAND(disk, db_getdiskbyname)
400 if (modif[0] == '\0') {
401 db_error("usage: show disk/devicename");
404 dev = getdiskbyname(modif);
406 db_printf("dev_t = %p\n", dev);
408 db_printf("No disk device matched.\n");