d970bcc9db
The kernel certainly doesn't use _PATH_DEV or even /dev/ to find the device. It cannot, since "/" has not been mounted. Maybe the only affect of using /dev/ is that it gets put in the mounted-from name for "/", so that mount(8), etc., display an absolute path before "/" has been remounted. Many have never bothered typing the full path, and code that constructs a path in rootdevnames[] never bothered to construct a full path, so the example shouldn't have it. Submitted by: bde
386 lines
8.8 KiB
C
386 lines
8.8 KiB
C
/*-
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* Copyright (c) 1999 Michael Smith
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* All rights reserved.
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* Copyright (c) 1999 Poul-Henning Kamp
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* Locate and mount the root filesystem.
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*
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* The root filesystem is detailed in the kernel environment variable
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* vfs.root.mountfrom, which is expected to be in the general format
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*
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* <vfsname>:[<path>]
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* vfsname := the name of a VFS known to the kernel and capable
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* of being mounted as root
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* path := disk device name or other data used by the filesystem
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* to locate its physical store
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*
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*/
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#include "opt_rootdevname.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/malloc.h>
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#include <sys/reboot.h>
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#include <sys/diskslice.h>
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#include <sys/disklabel.h>
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#include <sys/conf.h>
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#include <sys/cons.h>
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#include <sys/proc.h>
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#include "opt_ddb.h"
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#ifdef DDB
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#include <ddb/ddb.h>
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#endif
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#include <paths.h>
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MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
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#define ROOTNAME "root_device"
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struct vnode *rootvnode;
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/*
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* The root specifiers we will try if RB_CDROM is specified.
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*/
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static char *cdrom_rootdevnames[] = {
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"cd9660:cd0a",
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"cd9660:acd0a",
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"cd9660:wcd0a",
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NULL
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};
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static void vfs_mountroot(void *junk);
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static int vfs_mountroot_try(char *mountfrom);
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static int vfs_mountroot_ask(void);
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static void gets(char *cp);
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/* legacy find-root code */
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char *rootdevnames[2] = {NULL, NULL};
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static int setrootbyname(char *name);
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SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
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/*
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* Find and mount the root filesystem
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*/
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static void
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vfs_mountroot(void *junk)
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{
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int i;
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/*
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* The root filesystem information is compiled in, and we are
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* booted with instructions to use it.
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*/
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#ifdef ROOTDEVNAME
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if ((boothowto & RB_DFLTROOT) &&
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!vfs_mountroot_try(ROOTDEVNAME))
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return;
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#endif
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/*
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* We are booted with instructions to prompt for the root filesystem,
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* or to use the compiled-in default when it doesn't exist.
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*/
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if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
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if (!vfs_mountroot_ask())
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return;
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}
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/*
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* We've been given the generic "use CDROM as root" flag. This is
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* necessary because one media may be used in many different
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* devices, so we need to search for them.
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*/
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if (boothowto & RB_CDROM) {
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for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
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if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
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return;
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}
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}
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/*
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* Try to use the value read by the loader from /etc/fstab, or
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* supplied via some other means. This is the preferred
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* mechanism.
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*/
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if (!vfs_mountroot_try(getenv("vfs.root.mountfrom")))
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return;
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/*
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* Try values that may have been computed by the machine-dependant
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* legacy code.
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*/
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if (!vfs_mountroot_try(rootdevnames[0]))
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return;
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if (!vfs_mountroot_try(rootdevnames[1]))
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return;
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/*
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* If we have a compiled-in default, and haven't already tried it, try
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* it now.
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*/
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#ifdef ROOTDEVNAME
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if (!(boothowto & RB_DFLTROOT))
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if (!vfs_mountroot_try(ROOTDEVNAME))
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return;
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#endif
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/*
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* Everything so far has failed, prompt on the console if we haven't
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* already tried that.
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*/
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if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
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return;
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panic("Root mount failed, startup aborted.");
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}
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/*
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* Mount (mountfrom) as the root filesystem.
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*/
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static int
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vfs_mountroot_try(char *mountfrom)
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{
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struct mount *mp;
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char *vfsname, *path;
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int error;
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char patt[32];
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int s;
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vfsname = NULL;
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path = NULL;
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mp = NULL;
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error = EINVAL;
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if (mountfrom == NULL)
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return(error); /* don't complain */
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s = splcam(); /* Overkill, but annoying without it */
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printf("Mounting root from %s\n", mountfrom);
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splx(s);
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/* parse vfs name and path */
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vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
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path = malloc(MNAMELEN, M_MOUNT, M_WAITOK);
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vfsname[0] = path[0] = 0;
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sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
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if (sscanf(mountfrom, patt, vfsname, path) < 1)
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goto done;
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/* allocate a root mount */
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error = vfs_rootmountalloc(vfsname, path[0] != 0 ? path : ROOTNAME,
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&mp);
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if (error != 0) {
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printf("Can't allocate root mount for filesystem '%s': %d\n",
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vfsname, error);
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goto done;
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}
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mp->mnt_flag |= MNT_ROOTFS;
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/* do our best to set rootdev */
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if ((path[0] != 0) && setrootbyname(path))
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printf("setrootbyname failed\n");
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/* If the root device is a type "memory disk", mount RW */
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if (rootdev != NODEV && devsw(rootdev) &&
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(devsw(rootdev)->d_flags & D_MEMDISK))
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mp->mnt_flag &= ~MNT_RDONLY;
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/*
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* Set the mount path to be something useful, because the
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* filesystem code isn't responsible now for initialising
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* f_mntonname unless they want to override the default
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* (which is `path'.)
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*/
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strncpy(mp->mnt_stat.f_mntonname, "/", MNAMELEN);
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error = VFS_MOUNT(mp, NULL, NULL, NULL, curthread);
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done:
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if (vfsname != NULL)
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free(vfsname, M_MOUNT);
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if (path != NULL)
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free(path, M_MOUNT);
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if (error != 0) {
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if (mp != NULL) {
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vfs_unbusy(mp, curthread);
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free(mp, M_MOUNT);
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}
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printf("Root mount failed: %d\n", error);
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} else {
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/* register with list of mounted filesystems */
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mtx_lock(&mountlist_mtx);
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TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
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mtx_unlock(&mountlist_mtx);
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/* sanity check system clock against root filesystem timestamp */
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inittodr(mp->mnt_time);
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vfs_unbusy(mp, curthread);
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}
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return(error);
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}
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/*
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* Spin prompting on the console for a suitable root filesystem
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*/
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static int
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vfs_mountroot_ask(void)
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{
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char name[128];
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int i;
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dev_t dev;
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for(;;) {
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printf("\nManual root filesystem specification:\n");
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printf(" <fstype>:<device> Mount <device> using filesystem <fstype>\n");
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#if defined(__i386__) || defined(__ia64__)
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printf(" eg. ufs:da0s1a\n");
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#else
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printf(" eg. ufs:da0a\n");
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#endif
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printf(" ? List valid disk boot devices\n");
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printf(" <empty line> Abort manual input\n");
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printf("\nmountroot> ");
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gets(name);
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if (name[0] == 0)
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return(1);
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if (name[0] == '?') {
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printf("Possibly valid devices for 'ufs' root:\n");
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for (i = 0; i < NUMCDEVSW; i++) {
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dev = makedev(i, 0);
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if (devsw(dev) != NULL)
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printf(" \"%s\"", devsw(dev)->d_name);
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}
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printf("\n");
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continue;
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}
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if (!vfs_mountroot_try(name))
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return(0);
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}
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}
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static void
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gets(char *cp)
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{
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char *lp;
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int c;
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lp = cp;
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for (;;) {
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printf("%c", c = cngetc() & 0177);
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switch (c) {
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case -1:
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case '\n':
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case '\r':
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*lp++ = '\0';
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return;
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case '\b':
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case '\177':
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if (lp > cp) {
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printf(" \b");
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lp--;
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}
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continue;
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case '#':
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lp--;
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if (lp < cp)
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lp = cp;
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continue;
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case '@':
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case 'u' & 037:
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lp = cp;
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printf("%c", '\n');
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continue;
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default:
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*lp++ = c;
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}
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}
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}
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/*
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* Convert a given name to the dev_t of the disk-like device
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* it refers to.
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*/
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dev_t
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getdiskbyname(char *name) {
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char *cp;
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dev_t dev;
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cp = name;
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if (!bcmp(cp, "/dev/", 5))
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cp += 5;
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dev = NODEV;
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EVENTHANDLER_INVOKE(dev_clone, cp, strlen(cp), &dev);
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return (dev);
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}
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/*
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* Set rootdev to match (name), given that we expect it to
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* refer to a disk-like device.
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*/
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static int
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setrootbyname(char *name)
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{
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dev_t diskdev;
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diskdev = getdiskbyname(name);
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if (diskdev != NODEV) {
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rootdev = diskdev;
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return (0);
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}
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return (1);
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}
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#ifdef DDB
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DB_SHOW_COMMAND(disk, db_getdiskbyname)
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{
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dev_t dev;
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if (modif[0] == '\0') {
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db_error("usage: show disk/devicename");
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return;
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}
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dev = getdiskbyname(modif);
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if (dev != NODEV)
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db_printf("dev_t = %p\n", dev);
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else
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db_printf("No disk device matched.\n");
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}
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#endif
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