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 $
29 * $DragonFly: src/sys/kern/vfs_conf.c,v 1.34 2008/05/24 19:08:28 dillon Exp $
33 * Locate and mount the root filesystem.
35 * The root filesystem is detailed in the kernel environment variable
36 * vfs.root.mountfrom, which is expected to be in the general format
39 * vfsname := the name of a VFS known to the kernel and capable
40 * of being mounted as root
41 * path := disk device name or other data used by the filesystem
42 * to locate its physical store
46 #include "opt_rootdevname.h"
48 #include <sys/param.h>
49 #include <sys/kernel.h>
50 #include <sys/systm.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>
59 #include <sys/device.h>
60 #include <sys/namecache.h>
61 #include <sys/paths.h>
62 #include <sys/thread2.h>
69 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
71 #define ROOTNAME "root_device"
73 struct vnode *rootvnode;
74 struct nchandle rootnch;
77 * The root specifiers we will try if RB_CDROM is specified. Note that
78 * the ATA driver will accept acd*a and acd*c, but the SCSI driver
79 * will only accept cd*c, so use 'c'.
81 * XXX TGEN NATA and, presumably, 'old'ATA will also accept the device name
82 * without any fake partition, since the major & minor are identical for all
83 * three (acd*, acd*a and acd*c). However, due to an as-of-yet undiscovered
84 * bug, acd0c ends up with minor 2 when using NATA and booting cold. Since
85 * NATA's acd_open() is unable to fulfill mounts on such 'ghost' cdevs, acd0
86 * and acd1 have been added to the list of CD-ROM root device names.
88 static char *cdrom_rootdevnames[] = {
98 static void vfs_mountroot(void *junk);
99 static int vfs_mountroot_try(const char *mountfrom);
100 static int vfs_mountroot_ask(void);
101 static int getline(char *cp, int limit);
103 /* legacy find-root code */
104 char *rootdevnames[2] = {NULL, NULL};
105 static int setrootbyname(char *name);
107 SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
110 * Find and mount the root filesystem
113 vfs_mountroot(void *junk)
116 cdev_t save_rootdev = rootdev;
119 * The root filesystem information is compiled in, and we are
120 * booted with instructions to use it.
123 if ((boothowto & RB_DFLTROOT) &&
124 !vfs_mountroot_try(ROOTDEVNAME))
128 * We are booted with instructions to prompt for the root filesystem,
129 * or to use the compiled-in default when it doesn't exist.
131 if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
132 if (!vfs_mountroot_ask())
137 * We've been given the generic "use CDROM as root" flag. This is
138 * necessary because one media may be used in many different
139 * devices, so we need to search for them.
141 if (boothowto & RB_CDROM) {
142 for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
143 if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
149 * Try to use the value read by the loader from /etc/fstab, or
150 * supplied via some other means. This is the preferred
153 if (!vfs_mountroot_try(kgetenv("vfs.root.mountfrom")))
157 * If a vfs set rootdev, try it (XXX VINUM HACK!)
159 if (save_rootdev != NULL) {
160 rootdev = save_rootdev;
161 if (!vfs_mountroot_try(""))
166 * Try values that may have been computed by the machine-dependant
169 if (rootdevnames[0] && !vfs_mountroot_try(rootdevnames[0]))
171 if (rootdevnames[1] && !vfs_mountroot_try(rootdevnames[1]))
175 * If we have a compiled-in default, and haven't already tried it, try
179 if (!(boothowto & RB_DFLTROOT))
180 if (!vfs_mountroot_try(ROOTDEVNAME))
185 * Everything so far has failed, prompt on the console if we haven't
186 * already tried that.
188 if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
190 panic("Root mount failed, startup aborted.");
194 * Mount (mountfrom) as the root filesystem.
197 vfs_mountroot_try(const char *mountfrom)
200 char *vfsname, *devname;
209 if (mountfrom == NULL)
210 return(error); /* don't complain */
213 kprintf("Mounting root from %s\n", mountfrom);
216 /* parse vfs name and devname */
217 vfsname = kmalloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
218 devname = kmalloc(MNAMELEN, M_MOUNT, M_WAITOK);
219 vfsname[0] = devname[0] = 0;
220 ksprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
221 if (ksscanf(mountfrom, patt, vfsname, devname) < 1)
224 /* allocate a root mount */
225 error = vfs_rootmountalloc(vfsname,
226 devname[0] != 0 ? devname : ROOTNAME, &mp);
228 kprintf("Can't allocate root mount for filesystem '%s': %d\n",
232 mp->mnt_flag |= MNT_ROOTFS;
234 /* do our best to set rootdev */
235 if ((devname[0] != 0) && setrootbyname(devname))
236 kprintf("setrootbyname failed\n");
238 /* If the root device is a type "memory disk", mount RW */
239 if (rootdev != NULL && dev_is_good(rootdev) &&
240 (dev_dflags(rootdev) & D_MEMDISK)) {
241 mp->mnt_flag &= ~MNT_RDONLY;
244 error = VFS_MOUNT(mp, NULL, NULL, proc0.p_ucred);
248 kfree(vfsname, M_MOUNT);
250 kfree(devname, M_MOUNT);
252 /* register with list of mounted filesystems */
253 mountlist_insert(mp, MNTINS_FIRST);
255 /* sanity check system clock against root fs timestamp */
256 inittodr(mp->mnt_time);
258 if (mp->mnt_syncer == NULL) {
259 error = vfs_allocate_syncvnode(mp);
261 kprintf("Warning: no syncer vp for root!\n");
269 kprintf("Root mount failed: %d\n", error);
275 * Spin prompting on the console for a suitable root filesystem
277 static int vfs_mountroot_ask_callback(struct dev_ops *ops, void *arg);
280 vfs_mountroot_ask(void)
285 kprintf("\nManual root filesystem specification:\n");
286 kprintf(" <fstype>:<device> Specify root (e.g. ufs:da0s1a)\n");
287 kprintf(" ? List valid disk boot devices\n");
288 kprintf(" panic Just panic\n");
289 kprintf(" abort Abort manual input\n");
291 kprintf("\nmountroot> ");
293 if (getline(name, 128) < 0)
297 } else if (name[0] == '?') {
298 kprintf("Possibly valid devices for 'ufs' root:\n");
299 dev_ops_scan(vfs_mountroot_ask_callback, NULL);
302 } else if (strcmp(name, "panic") == 0) {
303 panic("panic from console");
304 } else if (strcmp(name, "abort") == 0) {
306 } else if (vfs_mountroot_try(name) == 0) {
314 vfs_mountroot_ask_callback(struct dev_ops *ops, void *arg __unused)
318 dev = get_dev(ops->head.maj, 0);
319 if (dev_is_good(dev) && (dev_dflags(dev) & D_DISK))
320 kprintf(" \"%s\"", dev_dname(dev));
325 getline(char *cp, int limit)
363 if (lp - cp >= limit - 1) {
375 * Convert a given name to the cdev_t of the disk-like device
385 static int kgetdiskbyname_callback(struct dev_ops *ops, void *arg);
388 kgetdiskbyname(const char *name)
392 int unit, slice, part;
394 struct kdbn_info info;
397 * Get the base name of the device
399 if (strncmp(name, __SYS_PATH_DEV, sizeof(__SYS_PATH_DEV) - 1) == 0)
400 name += sizeof(__SYS_PATH_DEV) - 1;
401 cp = __DECONST(char *, name);
404 while (*cp >= 'a' && *cp <= 'z')
407 kprintf("missing device name\n");
415 unit = strtol(cp, &cp, 10);
416 if (name + nlen == (const char *)cp || unit < 0 || unit >= DKMAXUNITS) {
417 kprintf("bad unit: %d\n", unit);
422 * Get the slice. Note that if no partition or partition 'a' is
423 * specified, and no slice is specified, we will try both 'ad0a'
424 * (which is what you get when slice is 0), and also 'ad0' (the
425 * whole-disk partition, slice == 1).
439 if (*cp >= 'a' && *cp <= 'p') {
447 kprintf("junk after name: %s\n", cp);
454 bzero(&info, sizeof(info));
457 info.minor = dkmakeminor(unit, slice, part);
458 dev_ops_scan(kgetdiskbyname_callback, &info);
459 if (info.dev == NULL) {
460 kprintf("no disk named '%s'\n", name);
467 rdev = make_sub_dev(info.dev, info.minor);
472 kgetdiskbyname_callback(struct dev_ops *ops, void *arg)
474 struct kdbn_info *info = arg;
478 dev = get_dev(ops->head.maj, info->minor);
479 if (dev_is_good(dev) && (dname = dev_dname(dev)) != NULL) {
480 if (strlen(dname) == info->nlen &&
481 strncmp(dname, info->name, info->nlen) == 0) {
490 * Set rootdev to match (name), given that we expect it to
491 * refer to a disk-like device.
494 setrootbyname(char *name)
498 diskdev = kgetdiskbyname(name);
499 if (diskdev != NULL) {
508 DB_SHOW_COMMAND(disk, db_getdiskbyname)
512 if (modif[0] == '\0') {
513 db_error("usage: show disk/devicename");
516 dev = kgetdiskbyname(modif);
518 db_printf("cdev_t = %p\n", dev);
520 db_printf("No disk device matched.\n");