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-rw-r--r--sys/kern/vfs_mountroot.c626
1 files changed, 626 insertions, 0 deletions
diff --git a/sys/kern/vfs_mountroot.c b/sys/kern/vfs_mountroot.c
new file mode 100644
index 0000000..8685547
--- /dev/null
+++ b/sys/kern/vfs_mountroot.c
@@ -0,0 +1,626 @@
+/*-
+ * Copyright (c) 1999-2004 Poul-Henning Kamp
+ * Copyright (c) 1999 Michael Smith
+ * Copyright (c) 1989, 1993
+ * The Regents of the University of California. All rights reserved.
+ * (c) UNIX System Laboratories, Inc.
+ * All or some portions of this file are derived from material licensed
+ * to the University of California by American Telephone and Telegraph
+ * Co. or Unix System Laboratories, Inc. and are reproduced herein with
+ * the permission of UNIX System Laboratories, Inc.
+ *
+ * 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.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/conf.h>
+#include <sys/fcntl.h>
+#include <sys/jail.h>
+#include <sys/kernel.h>
+#include <sys/libkern.h>
+#include <sys/malloc.h>
+#include <sys/mount.h>
+#include <sys/mutex.h>
+#include <sys/namei.h>
+#include <sys/priv.h>
+#include <sys/proc.h>
+#include <sys/filedesc.h>
+#include <sys/reboot.h>
+#include <sys/syscallsubr.h>
+#include <sys/sysproto.h>
+#include <sys/sx.h>
+#include <sys/sysctl.h>
+#include <sys/sysent.h>
+#include <sys/systm.h>
+#include <sys/vnode.h>
+#include <vm/uma.h>
+
+#include <geom/geom.h>
+
+#include <machine/stdarg.h>
+
+#include "opt_rootdevname.h"
+
+#define ROOTNAME "root_device"
+
+static int vfs_mountroot_ask(void);
+static int vfs_mountroot_try(const char *mountfrom, const char *options);
+
+/*
+ * The vnode of the system's root (/ in the filesystem, without chroot
+ * active.)
+ */
+struct vnode *rootvnode;
+
+/*
+ * 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>:[<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
+ *
+ * If the environment variable vfs.root.mountfrom is a space separated list,
+ * each list element is tried in turn and the root filesystem will be mounted
+ * from the first one that suceeds.
+ *
+ * The environment variable vfs.root.mountfrom.options is a comma delimited
+ * set of string mount options. These mount options must be parseable
+ * by nmount() in the kernel.
+ */
+
+/*
+ * The root specifiers we will try if RB_CDROM is specified.
+ */
+static char *cdrom_rootdevnames[] = {
+ "cd9660:cd0",
+ "cd9660:acd0",
+ NULL
+};
+
+/* legacy find-root code */
+char *rootdevnames[2] = {NULL, NULL};
+#ifndef ROOTDEVNAME
+# define ROOTDEVNAME NULL
+#endif
+static const char *ctrootdevname = ROOTDEVNAME;
+
+struct root_hold_token {
+ const char *who;
+ LIST_ENTRY(root_hold_token) list;
+};
+
+static LIST_HEAD(, root_hold_token) root_holds =
+ LIST_HEAD_INITIALIZER(root_holds);
+
+static int root_mount_complete;
+
+struct root_hold_token *
+root_mount_hold(const char *identifier)
+{
+ struct root_hold_token *h;
+
+ if (root_mounted())
+ return (NULL);
+
+ h = malloc(sizeof *h, M_DEVBUF, M_ZERO | M_WAITOK);
+ h->who = identifier;
+ mtx_lock(&mountlist_mtx);
+ LIST_INSERT_HEAD(&root_holds, h, list);
+ mtx_unlock(&mountlist_mtx);
+ return (h);
+}
+
+void
+root_mount_rel(struct root_hold_token *h)
+{
+
+ if (h == NULL)
+ return;
+ mtx_lock(&mountlist_mtx);
+ LIST_REMOVE(h, list);
+ wakeup(&root_holds);
+ mtx_unlock(&mountlist_mtx);
+ free(h, M_DEVBUF);
+}
+
+static void
+root_mount_prepare(void)
+{
+ struct root_hold_token *h;
+ struct timeval lastfail;
+ int curfail = 0;
+
+ for (;;) {
+ DROP_GIANT();
+ g_waitidle();
+ PICKUP_GIANT();
+ mtx_lock(&mountlist_mtx);
+ if (LIST_EMPTY(&root_holds)) {
+ mtx_unlock(&mountlist_mtx);
+ break;
+ }
+ if (ppsratecheck(&lastfail, &curfail, 1)) {
+ printf("Root mount waiting for:");
+ LIST_FOREACH(h, &root_holds, list)
+ printf(" %s", h->who);
+ printf("\n");
+ }
+ msleep(&root_holds, &mountlist_mtx, PZERO | PDROP, "roothold",
+ hz);
+ }
+}
+
+static void
+root_mount_done(void)
+{
+
+ /* Keep prison0's root in sync with the global rootvnode. */
+ mtx_lock(&prison0.pr_mtx);
+ prison0.pr_root = rootvnode;
+ vref(prison0.pr_root);
+ mtx_unlock(&prison0.pr_mtx);
+ /*
+ * Use a mutex to prevent the wakeup being missed and waiting for
+ * an extra 1 second sleep.
+ */
+ mtx_lock(&mountlist_mtx);
+ root_mount_complete = 1;
+ wakeup(&root_mount_complete);
+ mtx_unlock(&mountlist_mtx);
+}
+
+int
+root_mounted(void)
+{
+
+ /* No mutex is acquired here because int stores are atomic. */
+ return (root_mount_complete);
+}
+
+void
+root_mount_wait(void)
+{
+
+ /*
+ * Panic on an obvious deadlock - the function can't be called from
+ * a thread which is doing the whole SYSINIT stuff.
+ */
+ KASSERT(curthread->td_proc->p_pid != 0,
+ ("root_mount_wait: cannot be called from the swapper thread"));
+ mtx_lock(&mountlist_mtx);
+ while (!root_mount_complete) {
+ msleep(&root_mount_complete, &mountlist_mtx, PZERO, "rootwait",
+ hz);
+ }
+ mtx_unlock(&mountlist_mtx);
+}
+
+static void
+set_rootvnode(void)
+{
+ struct proc *p;
+
+ if (VFS_ROOT(TAILQ_FIRST(&mountlist), LK_EXCLUSIVE, &rootvnode))
+ panic("Cannot find root vnode");
+
+ VOP_UNLOCK(rootvnode, 0);
+
+ p = curthread->td_proc;
+ FILEDESC_XLOCK(p->p_fd);
+
+ if (p->p_fd->fd_cdir != NULL)
+ vrele(p->p_fd->fd_cdir);
+ p->p_fd->fd_cdir = rootvnode;
+ VREF(rootvnode);
+
+ if (p->p_fd->fd_rdir != NULL)
+ vrele(p->p_fd->fd_rdir);
+ p->p_fd->fd_rdir = rootvnode;
+ VREF(rootvnode);
+
+ FILEDESC_XUNLOCK(p->p_fd);
+
+ EVENTHANDLER_INVOKE(mountroot);
+}
+
+static void
+devfs_first(void)
+{
+ struct thread *td = curthread;
+ struct vfsoptlist *opts;
+ struct vfsconf *vfsp;
+ struct mount *mp = NULL;
+ int error;
+
+ vfsp = vfs_byname("devfs");
+ KASSERT(vfsp != NULL, ("Could not find devfs by name"));
+ if (vfsp == NULL)
+ return;
+
+ mp = vfs_mount_alloc(NULLVP, vfsp, "/dev", td->td_ucred);
+
+ error = VFS_MOUNT(mp);
+ KASSERT(error == 0, ("VFS_MOUNT(devfs) failed %d", error));
+ if (error)
+ return;
+
+ opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
+ TAILQ_INIT(opts);
+ mp->mnt_opt = opts;
+
+ mtx_lock(&mountlist_mtx);
+ TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
+ mtx_unlock(&mountlist_mtx);
+
+ set_rootvnode();
+
+ error = kern_symlink(td, "/", "dev", UIO_SYSSPACE);
+ if (error)
+ printf("kern_symlink /dev -> / returns %d\n", error);
+}
+
+static void
+devfs_fixup(struct thread *td)
+{
+ struct nameidata nd;
+ struct vnode *vp, *dvp;
+ struct mount *mp;
+ int error;
+
+ /* Remove our devfs mount from the mountlist and purge the cache */
+ mtx_lock(&mountlist_mtx);
+ mp = TAILQ_FIRST(&mountlist);
+ TAILQ_REMOVE(&mountlist, mp, mnt_list);
+ mtx_unlock(&mountlist_mtx);
+ cache_purgevfs(mp);
+
+ VFS_ROOT(mp, LK_EXCLUSIVE, &dvp);
+ VI_LOCK(dvp);
+ dvp->v_iflag &= ~VI_MOUNT;
+ VI_UNLOCK(dvp);
+ dvp->v_mountedhere = NULL;
+
+ /* Set up the real rootvnode, and purge the cache */
+ TAILQ_FIRST(&mountlist)->mnt_vnodecovered = NULL;
+ set_rootvnode();
+ cache_purgevfs(rootvnode->v_mount);
+
+ NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, "/dev", td);
+ error = namei(&nd);
+ if (error) {
+ printf("Lookup of /dev for devfs, error: %d\n", error);
+ vput(dvp);
+ vfs_unbusy(mp);
+ return;
+ }
+ NDFREE(&nd, NDF_ONLY_PNBUF);
+ vp = nd.ni_vp;
+ if (vp->v_type != VDIR) {
+ printf("/dev is not a directory\n");
+ vput(dvp);
+ vput(vp);
+ vfs_unbusy(mp);
+ return;
+ }
+ error = vinvalbuf(vp, V_SAVE, 0, 0);
+ if (error) {
+ printf("vinvalbuf() of /dev failed, error: %d\n", error);
+ vput(dvp);
+ vput(vp);
+ vfs_unbusy(mp);
+ return;
+ }
+ cache_purge(vp);
+ mp->mnt_vnodecovered = vp;
+ vp->v_mountedhere = mp;
+ mtx_lock(&mountlist_mtx);
+ TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
+ mtx_unlock(&mountlist_mtx);
+ VOP_UNLOCK(vp, 0);
+ vput(dvp);
+ vfs_unbusy(mp);
+
+ /* Unlink the no longer needed /dev/dev -> / symlink */
+ error = kern_unlink(td, "/dev/dev", UIO_SYSSPACE);
+ if (error)
+ printf("kern_unlink of /dev/dev failed, error: %d\n", error);
+}
+
+void
+vfs_mountroot(void)
+{
+ char *cp, *cpt, *options, *tmpdev;
+ int error, i, asked = 0;
+
+ options = NULL;
+
+ root_mount_prepare();
+
+ devfs_first();
+
+ /*
+ * We are booted with instructions to prompt for the root filesystem.
+ */
+ if (boothowto & RB_ASKNAME) {
+ if (!vfs_mountroot_ask())
+ goto mounted;
+ asked = 1;
+ }
+
+ options = getenv("vfs.root.mountfrom.options");
+
+ /*
+ * The root filesystem information is compiled in, and we are
+ * booted with instructions to use it.
+ */
+ if (ctrootdevname != NULL && (boothowto & RB_DFLTROOT)) {
+ if (!vfs_mountroot_try(ctrootdevname, options))
+ goto mounted;
+ ctrootdevname = NULL;
+ }
+
+ /*
+ * 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], options))
+ goto mounted;
+ }
+ }
+
+ /*
+ * Try to use the value read by the loader from /etc/fstab, or
+ * supplied via some other means. This is the preferred
+ * mechanism.
+ */
+ cp = getenv("vfs.root.mountfrom");
+ if (cp != NULL) {
+ cpt = cp;
+ while ((tmpdev = strsep(&cpt, " \t")) != NULL) {
+ error = vfs_mountroot_try(tmpdev, options);
+ if (error == 0) {
+ freeenv(cp);
+ goto mounted;
+ }
+ }
+ freeenv(cp);
+ }
+
+ /*
+ * Try values that may have been computed by code during boot
+ */
+ if (!vfs_mountroot_try(rootdevnames[0], options))
+ goto mounted;
+ if (!vfs_mountroot_try(rootdevnames[1], options))
+ goto mounted;
+
+ /*
+ * If we (still) have a compiled-in default, try it.
+ */
+ if (ctrootdevname != NULL)
+ if (!vfs_mountroot_try(ctrootdevname, options))
+ goto mounted;
+ /*
+ * Everything so far has failed, prompt on the console if we haven't
+ * already tried that.
+ */
+ if (!asked)
+ if (!vfs_mountroot_ask())
+ goto mounted;
+
+ panic("Root mount failed, startup aborted.");
+
+mounted:
+ root_mount_done();
+ freeenv(options);
+}
+
+static struct mntarg *
+parse_mountroot_options(struct mntarg *ma, const char *options)
+{
+ char *p;
+ char *name, *name_arg;
+ char *val, *val_arg;
+ char *opts;
+
+ if (options == NULL || options[0] == '\0')
+ return (ma);
+
+ p = opts = strdup(options, M_MOUNT);
+ if (opts == NULL) {
+ return (ma);
+ }
+
+ while((name = strsep(&p, ",")) != NULL) {
+ if (name[0] == '\0')
+ break;
+
+ val = strchr(name, '=');
+ if (val != NULL) {
+ *val = '\0';
+ ++val;
+ }
+ if( strcmp(name, "rw") == 0 ||
+ strcmp(name, "noro") == 0) {
+ /*
+ * The first time we mount the root file system,
+ * we need to mount 'ro', so We need to ignore
+ * 'rw' and 'noro' mount options.
+ */
+ continue;
+ }
+ name_arg = strdup(name, M_MOUNT);
+ val_arg = NULL;
+ if (val != NULL)
+ val_arg = strdup(val, M_MOUNT);
+
+ ma = mount_arg(ma, name_arg, val_arg,
+ (val_arg != NULL ? -1 : 0));
+ }
+ free(opts, M_MOUNT);
+ return (ma);
+}
+
+/*
+ * Mount (mountfrom) as the root filesystem.
+ */
+static int
+vfs_mountroot_try(const char *mountfrom, const char *options)
+{
+ struct mount *mp;
+ struct mntarg *ma;
+ char *vfsname, *path;
+ time_t timebase;
+ int error;
+ char patt[32];
+ char errmsg[255];
+
+ vfsname = NULL;
+ path = NULL;
+ mp = NULL;
+ ma = NULL;
+ error = EINVAL;
+ bzero(errmsg, sizeof(errmsg));
+
+ if (mountfrom == NULL)
+ return (error); /* don't complain */
+ printf("Trying to mount root from %s\n", mountfrom);
+
+ /* 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 out;
+
+ if (path[0] == '\0')
+ strcpy(path, ROOTNAME);
+
+ ma = mount_arg(ma, "fstype", vfsname, -1);
+ ma = mount_arg(ma, "fspath", "/", -1);
+ ma = mount_arg(ma, "from", path, -1);
+ ma = mount_arg(ma, "errmsg", errmsg, sizeof(errmsg));
+ ma = mount_arg(ma, "ro", NULL, 0);
+ ma = parse_mountroot_options(ma, options);
+ error = kernel_mount(ma, MNT_ROOTFS);
+
+ if (error == 0) {
+ /*
+ * We mount devfs prior to mounting the / FS, so the first
+ * entry will typically be devfs.
+ */
+ mp = TAILQ_FIRST(&mountlist);
+ KASSERT(mp != NULL, ("%s: mountlist is empty", __func__));
+
+ /*
+ * Iterate over all currently mounted file systems and use
+ * the time stamp found to check and/or initialize the RTC.
+ * Typically devfs has no time stamp and the only other FS
+ * is the actual / FS.
+ * Call inittodr() only once and pass it the largest of the
+ * timestamps we encounter.
+ */
+ timebase = 0;
+ do {
+ if (mp->mnt_time > timebase)
+ timebase = mp->mnt_time;
+ mp = TAILQ_NEXT(mp, mnt_list);
+ } while (mp != NULL);
+ inittodr(timebase);
+
+ devfs_fixup(curthread);
+ }
+
+ if (error != 0 ) {
+ printf("ROOT MOUNT ERROR: %s\n", errmsg);
+ printf("If you have invalid mount options, reboot, and ");
+ printf("first try the following from\n");
+ printf("the loader prompt:\n\n");
+ printf(" set vfs.root.mountfrom.options=rw\n\n");
+ printf("and then remove invalid mount options from ");
+ printf("/etc/fstab.\n\n");
+ }
+out:
+ free(path, M_MOUNT);
+ free(vfsname, M_MOUNT);
+ return (error);
+}
+
+static int
+vfs_mountroot_ask(void)
+{
+ char name[128];
+ char *mountfrom;
+ char *options;
+
+ for(;;) {
+ printf("Loader variables:\n");
+ printf("vfs.root.mountfrom=");
+ mountfrom = getenv("vfs.root.mountfrom");
+ if (mountfrom != NULL) {
+ printf("%s", mountfrom);
+ }
+ printf("\n");
+ printf("vfs.root.mountfrom.options=");
+ options = getenv("vfs.root.mountfrom.options");
+ if (options != NULL) {
+ printf("%s", options);
+ }
+ printf("\n");
+ freeenv(mountfrom);
+ freeenv(options);
+ printf("\nManual root filesystem specification:\n");
+ printf(" <fstype>:<device> Mount <device> using filesystem <fstype>\n");
+ printf(" eg. zfs:tank\n");
+ printf(" eg. ufs:/dev/da0s1a\n");
+ printf(" eg. cd9660:/dev/acd0\n");
+ printf(" This is equivalent to: ");
+ printf("mount -t cd9660 /dev/acd0 /\n");
+ printf("\n");
+ printf(" ? List valid disk boot devices\n");
+ printf(" <empty line> Abort manual input\n");
+ printf("\nmountroot> ");
+ gets(name, sizeof(name), 1);
+ if (name[0] == '\0')
+ return (1);
+ if (name[0] == '?') {
+ printf("\nList of GEOM managed disk devices:\n ");
+ g_dev_print();
+ continue;
+ }
+ if (!vfs_mountroot_try(name, NULL))
+ return (0);
+ }
+}
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