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-rw-r--r--sys/kern/vfs_conf.c396
1 files changed, 396 insertions, 0 deletions
diff --git a/sys/kern/vfs_conf.c b/sys/kern/vfs_conf.c
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+/*-
+ * Copyright (c) 1999 Michael Smith
+ * All rights reserved.
+ * Copyright (c) 1999 Poul-Henning Kamp
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * Locate and mount the root filesystem.
+ *
+ * The root filesystem is detailed in the kernel environment variable
+ * vfs.root.mountfrom, which is expected to be in the general format
+ *
+ * <vfsname>:[<path>]
+ * vfsname := the name of a VFS known to the kernel and capable
+ * of being mounted as root
+ * path := disk device name or other data used by the filesystem
+ * to locate its physical store
+ *
+ */
+
+#include "opt_rootdevname.h"
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/vnode.h>
+#include <sys/mount.h>
+#include <sys/malloc.h>
+#include <sys/reboot.h>
+#include <sys/diskslice.h>
+#include <sys/disklabel.h>
+#include <sys/conf.h>
+#include <sys/cons.h>
+#include <sys/proc.h>
+
+#include "opt_ddb.h"
+
+#ifdef DDB
+#include <ddb/ddb.h>
+#endif
+
+#include <paths.h>
+
+MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
+
+#define ROOTNAME "root_device"
+
+/*
+ * The vnode of the system's root (/ in the filesystem, without chroot
+ * active.)
+ */
+struct vnode *rootvnode;
+
+/*
+ * The root specifiers we will try if RB_CDROM is specified.
+ */
+static char *cdrom_rootdevnames[] = {
+ "cd9660:cd0a",
+ "cd9660:acd0a",
+ "cd9660:wcd0a",
+ NULL
+};
+
+static int vfs_mountroot_try(char *mountfrom);
+static int vfs_mountroot_ask(void);
+static void gets(char *cp);
+
+/* legacy find-root code */
+char *rootdevnames[2] = {NULL, NULL};
+static int setrootbyname(char *name);
+dev_t rootdev = NODEV;
+
+/*
+ * Find and mount the root filesystem
+ */
+void
+vfs_mountroot(void *foo __unused)
+{
+ char *cp;
+ int i, error;
+
+ /*
+ * The root filesystem information is compiled in, and we are
+ * booted with instructions to use it.
+ */
+#ifdef ROOTDEVNAME
+ if ((boothowto & RB_DFLTROOT) &&
+ !vfs_mountroot_try(ROOTDEVNAME))
+ return;
+#endif
+ /*
+ * We are booted with instructions to prompt for the root filesystem,
+ * or to use the compiled-in default when it doesn't exist.
+ */
+ if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
+ if (!vfs_mountroot_ask())
+ return;
+ }
+
+ /*
+ * We've been given the generic "use CDROM as root" flag. This is
+ * necessary because one media may be used in many different
+ * devices, so we need to search for them.
+ */
+ if (boothowto & RB_CDROM) {
+ for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
+ if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
+ return;
+ }
+ }
+
+ /*
+ * Try to use the value read by the loader from /etc/fstab, or
+ * supplied via some other means. This is the preferred
+ * mechanism.
+ */
+ if ((cp = getenv("vfs.root.mountfrom")) != NULL) {
+ error = vfs_mountroot_try(cp);
+ freeenv(cp);
+ if (!error)
+ return;
+ }
+
+ /*
+ * Try values that may have been computed by the machine-dependant
+ * legacy code.
+ */
+ if (!vfs_mountroot_try(rootdevnames[0]))
+ return;
+ if (!vfs_mountroot_try(rootdevnames[1]))
+ return;
+
+ /*
+ * If we have a compiled-in default, and haven't already tried it, try
+ * it now.
+ */
+#ifdef ROOTDEVNAME
+ if (!(boothowto & RB_DFLTROOT))
+ if (!vfs_mountroot_try(ROOTDEVNAME))
+ return;
+#endif
+
+ /*
+ * Everything so far has failed, prompt on the console if we haven't
+ * already tried that.
+ */
+ if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
+ return;
+ panic("Root mount failed, startup aborted.");
+}
+
+/*
+ * Mount (mountfrom) as the root filesystem.
+ */
+static int
+vfs_mountroot_try(char *mountfrom)
+{
+ struct mount *mp;
+ char *vfsname, *path;
+ int error;
+ char patt[32];
+ int s;
+
+ vfsname = NULL;
+ path = NULL;
+ mp = NULL;
+ error = EINVAL;
+
+ if (mountfrom == NULL)
+ return(error); /* don't complain */
+
+ s = splcam(); /* Overkill, but annoying without it */
+ printf("Mounting root from %s\n", mountfrom);
+ splx(s);
+
+ /* parse vfs name and path */
+ vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
+ path = malloc(MNAMELEN, M_MOUNT, M_WAITOK);
+ vfsname[0] = path[0] = 0;
+ sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
+ if (sscanf(mountfrom, patt, vfsname, path) < 1)
+ goto done;
+
+ /* allocate a root mount */
+ error = vfs_rootmountalloc(vfsname, path[0] != 0 ? path : ROOTNAME,
+ &mp);
+ if (error != 0) {
+ printf("Can't allocate root mount for filesystem '%s': %d\n",
+ vfsname, error);
+ goto done;
+ }
+ mp->mnt_flag |= MNT_ROOTFS;
+
+ /* do our best to set rootdev */
+ if ((path[0] != 0) && setrootbyname(path))
+ printf("setrootbyname failed\n");
+
+ /* If the root device is a type "memory disk", mount RW */
+ if (rootdev != NODEV && devsw(rootdev) &&
+ (devsw(rootdev)->d_flags & D_MEMDISK))
+ mp->mnt_flag &= ~MNT_RDONLY;
+
+ /*
+ * Set the mount path to be something useful, because the
+ * filesystem code isn't responsible now for initialising
+ * f_mntonname unless they want to override the default
+ * (which is `path'.)
+ */
+ strncpy(mp->mnt_stat.f_mntonname, "/", MNAMELEN);
+
+ error = VFS_MOUNT(mp, NULL, NULL, NULL, curthread);
+
+done:
+ if (vfsname != NULL)
+ free(vfsname, M_MOUNT);
+ if (path != NULL)
+ free(path, M_MOUNT);
+ if (error != 0) {
+ if (mp != NULL) {
+ vfs_unbusy(mp, curthread);
+ free(mp, M_MOUNT);
+ }
+ printf("Root mount failed: %d\n", error);
+ } else {
+
+ /* register with list of mounted filesystems */
+ mtx_lock(&mountlist_mtx);
+ TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
+ mtx_unlock(&mountlist_mtx);
+
+ /* sanity check system clock against root filesystem timestamp */
+ inittodr(mp->mnt_time);
+ vfs_unbusy(mp, curthread);
+ }
+ return(error);
+}
+
+/*
+ * Spin prompting on the console for a suitable root filesystem
+ */
+static int
+vfs_mountroot_ask(void)
+{
+ char name[128];
+ int i;
+ dev_t dev;
+
+ for(;;) {
+ printf("\nManual root filesystem specification:\n");
+ printf(" <fstype>:<device> Mount <device> using filesystem <fstype>\n");
+#if defined(__i386__) || defined(__ia64__)
+ printf(" eg. ufs:da0s1a\n");
+#else
+ printf(" eg. ufs:da0a\n");
+#endif
+ printf(" ? List valid disk boot devices\n");
+ printf(" <empty line> Abort manual input\n");
+ printf("\nmountroot> ");
+ gets(name);
+ if (name[0] == 0)
+ return(1);
+ if (name[0] == '?') {
+ printf("Possibly valid devices for 'ufs' root:\n");
+ for (i = 0; i < NUMCDEVSW; i++) {
+ dev = makedev(i, 0);
+ if (devsw(dev) != NULL)
+ printf(" \"%s\"", devsw(dev)->d_name);
+ }
+ printf("\n");
+ continue;
+ }
+ if (!vfs_mountroot_try(name))
+ return(0);
+ }
+}
+
+/*
+ * Local helper function for vfs_mountroot_ask.
+ */
+static void
+gets(char *cp)
+{
+ char *lp;
+ int c;
+
+ lp = cp;
+ for (;;) {
+ printf("%c", c = cngetc() & 0177);
+ switch (c) {
+ case -1:
+ case '\n':
+ case '\r':
+ *lp++ = '\0';
+ return;
+ case '\b':
+ case '\177':
+ if (lp > cp) {
+ printf(" \b");
+ lp--;
+ }
+ continue;
+ case '#':
+ lp--;
+ if (lp < cp)
+ lp = cp;
+ continue;
+ case '@':
+ case 'u' & 037:
+ lp = cp;
+ printf("%c", '\n');
+ continue;
+ default:
+ *lp++ = c;
+ }
+ }
+}
+
+/*
+ * Convert a given name to the dev_t of the disk-like device
+ * it refers to.
+ */
+dev_t
+getdiskbyname(char *name) {
+ char *cp;
+ dev_t dev;
+
+ cp = name;
+ if (!bcmp(cp, "/dev/", 5))
+ cp += 5;
+
+ dev = NODEV;
+ EVENTHANDLER_INVOKE(dev_clone, cp, strlen(cp), &dev);
+ return (dev);
+}
+
+/*
+ * Set rootdev to match (name), given that we expect it to
+ * refer to a disk-like device.
+ */
+static int
+setrootbyname(char *name)
+{
+ dev_t diskdev;
+
+ diskdev = getdiskbyname(name);
+ if (diskdev != NODEV) {
+ rootdev = diskdev;
+ return (0);
+ }
+
+ return (1);
+}
+
+/* Show the dev_t for a disk specified by name */
+#ifdef DDB
+DB_SHOW_COMMAND(disk, db_getdiskbyname)
+{
+ dev_t dev;
+
+ if (modif[0] == '\0') {
+ db_error("usage: show disk/devicename");
+ return;
+ }
+ dev = getdiskbyname(modif);
+ if (dev != NODEV)
+ db_printf("dev_t = %p\n", dev);
+ else
+ db_printf("No disk device matched.\n");
+}
+#endif
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