FreeBSD-5.3/sys/kern/vfs_mount.c
/*
* 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 REGENTS 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 REGENTS 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.
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/kern/vfs_mount.c,v 1.138 2004/07/30 22:08:52 phk Exp $");
#include <sys/param.h>
#include <sys/conf.h>
#include <sys/cons.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/linker.h>
#include <sys/mac.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/filedesc.h>
#include <sys/reboot.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 <geom/geom.h>
#include <machine/stdarg.h>
#include "opt_rootdevname.h"
#include "opt_ddb.h"
#include "opt_mac.h"
#ifdef DDB
#include <ddb/ddb.h>
#endif
#define ROOTNAME "root_device"
#define VFS_MOUNTARG_SIZE_MAX (1024 * 64)
static void checkdirs(struct vnode *olddp, struct vnode *newdp);
static void gets(char *cp);
static int vfs_domount(struct thread *td, const char *fstype,
char *fspath, int fsflags, void *fsdata, int compat);
static int vfs_mount_alloc(struct vnode *dvp, struct vfsconf *vfsp,
const char *fspath, struct thread *td, struct mount **mpp);
static int vfs_mountroot_ask(void);
static int vfs_mountroot_try(const char *mountfrom);
static int vfs_donmount(struct thread *td, int fsflags,
struct uio *fsoptions);
static int usermount = 0;
SYSCTL_INT(_vfs, OID_AUTO, usermount, CTLFLAG_RW, &usermount, 0,
"Unprivileged users may mount and unmount file systems");
MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
/* List of mounted filesystems. */
struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist);
/* For any iteration/modification of mountlist */
struct mtx mountlist_mtx;
/*
* 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 := 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
*/
/*
* 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};
struct cdev *rootdev = NULL;
#ifdef ROOTDEVNAME
const char *ctrootdevname = ROOTDEVNAME;
#else
const char *ctrootdevname = NULL;
#endif
/*
* Has to be dynamic as the value of rootdev can change; however, it can't
* change after the root is mounted, so a user process can't access this
* sysctl until after the value is unchangeable.
*/
static int
sysctl_rootdev(SYSCTL_HANDLER_ARGS)
{
int error;
/* _RD prevents this from happening. */
KASSERT(req->newptr == NULL, ("Attempt to change root device name"));
if (rootdev != NULL)
error = sysctl_handle_string(oidp, rootdev->si_name, 0, req);
else
error = sysctl_handle_string(oidp, "", 0, req);
return (error);
}
SYSCTL_PROC(_kern, OID_AUTO, rootdev, CTLTYPE_STRING | CTLFLAG_RD,
0, 0, sysctl_rootdev, "A", "Root file system device");
/* Remove one mount option. */
static void
vfs_freeopt(struct vfsoptlist *opts, struct vfsopt *opt)
{
TAILQ_REMOVE(opts, opt, link);
free(opt->name, M_MOUNT);
if (opt->value != NULL)
free(opt->value, M_MOUNT);
#ifdef INVARIANTS
else if (opt->len != 0)
panic("%s: mount option with NULL value but length != 0",
__func__);
#endif
free(opt, M_MOUNT);
}
/* Release all resources related to the mount options. */
static void
vfs_freeopts(struct vfsoptlist *opts)
{
struct vfsopt *opt;
while (!TAILQ_EMPTY(opts)) {
opt = TAILQ_FIRST(opts);
vfs_freeopt(opts, opt);
}
free(opts, M_MOUNT);
}
/*
* Check if options are equal (with or without the "no" prefix).
*/
static int
vfs_equalopts(const char *opt1, const char *opt2)
{
/* "opt" vs. "opt" or "noopt" vs. "noopt" */
if (strcmp(opt1, opt2) == 0)
return (1);
/* "noopt" vs. "opt" */
if (strncmp(opt1, "no", 2) == 0 && strcmp(opt1 + 2, opt2) == 0)
return (1);
/* "opt" vs. "noopt" */
if (strncmp(opt2, "no", 2) == 0 && strcmp(opt1, opt2 + 2) == 0)
return (1);
return (0);
}
/*
* If a mount option is specified several times,
* (with or without the "no" prefix) only keep
* the last occurence of it.
*/
static void
vfs_sanitizeopts(struct vfsoptlist *opts)
{
struct vfsopt *opt, *opt2, *tmp;
TAILQ_FOREACH_REVERSE(opt, opts, vfsoptlist, link) {
opt2 = TAILQ_PREV(opt, vfsoptlist, link);
while (opt2 != NULL) {
if (vfs_equalopts(opt->name, opt2->name)) {
tmp = TAILQ_PREV(opt2, vfsoptlist, link);
vfs_freeopt(opts, opt2);
opt2 = tmp;
} else {
opt2 = TAILQ_PREV(opt2, vfsoptlist, link);
}
}
}
}
/*
* Build a linked list of mount options from a struct uio.
*/
static int
vfs_buildopts(struct uio *auio, struct vfsoptlist **options)
{
struct vfsoptlist *opts;
struct vfsopt *opt;
size_t memused;
unsigned int i, iovcnt;
int error, namelen, optlen;
opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
TAILQ_INIT(opts);
memused = 0;
iovcnt = auio->uio_iovcnt;
for (i = 0; i < iovcnt; i += 2) {
opt = malloc(sizeof(struct vfsopt), M_MOUNT, M_WAITOK);
namelen = auio->uio_iov[i].iov_len;
optlen = auio->uio_iov[i + 1].iov_len;
opt->name = malloc(namelen, M_MOUNT, M_WAITOK);
opt->value = NULL;
opt->len = optlen;
/*
* Do this early, so jumps to "bad" will free the current
* option.
*/
TAILQ_INSERT_TAIL(opts, opt, link);
memused += sizeof(struct vfsopt) + optlen + namelen;
/*
* Avoid consuming too much memory, and attempts to overflow
* memused.
*/
if (memused > VFS_MOUNTARG_SIZE_MAX ||
optlen > VFS_MOUNTARG_SIZE_MAX ||
namelen > VFS_MOUNTARG_SIZE_MAX) {
error = EINVAL;
goto bad;
}
if (auio->uio_segflg == UIO_SYSSPACE) {
bcopy(auio->uio_iov[i].iov_base, opt->name, namelen);
} else {
error = copyin(auio->uio_iov[i].iov_base, opt->name,
namelen);
if (error)
goto bad;
}
/* Ensure names are null-terminated strings. */
if (opt->name[namelen - 1] != '\0') {
error = EINVAL;
goto bad;
}
if (optlen != 0) {
opt->value = malloc(optlen, M_MOUNT, M_WAITOK);
if (auio->uio_segflg == UIO_SYSSPACE) {
bcopy(auio->uio_iov[i + 1].iov_base, opt->value,
optlen);
} else {
error = copyin(auio->uio_iov[i + 1].iov_base,
opt->value, optlen);
if (error)
goto bad;
}
}
}
vfs_sanitizeopts(opts);
*options = opts;
return (0);
bad:
vfs_freeopts(opts);
return (error);
}
/*
* Merge the old mount options with the new ones passed
* in the MNT_UPDATE case.
*/
static void
vfs_mergeopts(struct vfsoptlist *toopts, struct vfsoptlist *opts)
{
struct vfsopt *opt, *opt2, *new;
TAILQ_FOREACH(opt, opts, link) {
/*
* Check that this option hasn't been redefined
* nor cancelled with a "no" mount option.
*/
opt2 = TAILQ_FIRST(toopts);
while (opt2 != NULL) {
if (strcmp(opt2->name, opt->name) == 0)
goto next;
if (strncmp(opt2->name, "no", 2) == 0 &&
strcmp(opt2->name + 2, opt->name) == 0) {
vfs_freeopt(toopts, opt2);
goto next;
}
opt2 = TAILQ_NEXT(opt2, link);
}
/* We want this option, duplicate it. */
new = malloc(sizeof(struct vfsopt), M_MOUNT, M_WAITOK);
new->name = malloc(strlen(opt->name) + 1, M_MOUNT, M_WAITOK);
strcpy(new->name, opt->name);
if (opt->len != 0) {
new->value = malloc(opt->len, M_MOUNT, M_WAITOK);
bcopy(opt->value, new->value, opt->len);
} else {
new->value = NULL;
}
new->len = opt->len;
TAILQ_INSERT_TAIL(toopts, new, link);
next:
continue;
}
}
/*
* New mount API.
*/
int
nmount(td, uap)
struct thread *td;
struct nmount_args /* {
struct iovec *iovp;
unsigned int iovcnt;
int flags;
} */ *uap;
{
struct uio *auio;
struct iovec *iov;
unsigned int i;
int error;
u_int iovcnt;
iovcnt = uap->iovcnt;
/*
* Check that we have an even number of iovec's
* and that we have at least two options.
*/
if ((iovcnt & 1) || (iovcnt < 4))
return (EINVAL);
error = copyinuio(uap->iovp, iovcnt, &auio);
if (error)
return (error);
iov = auio->uio_iov;
for (i = 0; i < iovcnt; i++) {
if (iov->iov_len > MMAXOPTIONLEN) {
free(auio, M_IOV);
return (EINVAL);
}
iov++;
}
error = vfs_donmount(td, uap->flags, auio);
free(auio, M_IOV);
return (error);
}
int
kernel_mount(struct iovec *iovp, u_int iovcnt, int flags)
{
struct uio auio;
int error;
/*
* Check that we have an even number of iovec's
* and that we have at least two options.
*/
if ((iovcnt & 1) || (iovcnt < 4))
return (EINVAL);
auio.uio_iov = iovp;
auio.uio_iovcnt = iovcnt;
auio.uio_segflg = UIO_SYSSPACE;
error = vfs_donmount(curthread, flags, &auio);
return (error);
}
int
kernel_vmount(int flags, ...)
{
struct iovec *iovp;
struct uio auio;
va_list ap;
u_int iovcnt, iovlen, len;
const char *cp;
char *buf, *pos;
size_t n;
int error, i;
len = 0;
va_start(ap, flags);
for (iovcnt = 0; (cp = va_arg(ap, const char *)) != NULL; iovcnt++)
len += strlen(cp) + 1;
va_end(ap);
if (iovcnt < 4 || iovcnt & 1)
return (EINVAL);
iovlen = iovcnt * sizeof (struct iovec);
MALLOC(iovp, struct iovec *, iovlen, M_MOUNT, M_WAITOK);
MALLOC(buf, char *, len, M_MOUNT, M_WAITOK);
pos = buf;
va_start(ap, flags);
for (i = 0; i < iovcnt; i++) {
cp = va_arg(ap, const char *);
copystr(cp, pos, len - (pos - buf), &n);
iovp[i].iov_base = pos;
iovp[i].iov_len = n;
pos += n;
}
va_end(ap);
auio.uio_iov = iovp;
auio.uio_iovcnt = iovcnt;
auio.uio_segflg = UIO_SYSSPACE;
error = vfs_donmount(curthread, flags, &auio);
FREE(iovp, M_MOUNT);
FREE(buf, M_MOUNT);
return (error);
}
/*
* Allocate and initialize the mount point struct.
*/
static int
vfs_mount_alloc(struct vnode *vp, struct vfsconf *vfsp,
const char *fspath, struct thread *td, struct mount **mpp)
{
struct mount *mp;
mp = malloc(sizeof(struct mount), M_MOUNT, M_WAITOK | M_ZERO);
TAILQ_INIT(&mp->mnt_nvnodelist);
mp->mnt_nvnodelistsize = 0;
mtx_init(&mp->mnt_mtx, "struct mount mtx", NULL, MTX_DEF);
lockinit(&mp->mnt_lock, PVFS, "vfslock", 0, LK_NOPAUSE);
vfs_busy(mp, LK_NOWAIT, 0, td);
mp->mnt_op = vfsp->vfc_vfsops;
mp->mnt_vfc = vfsp;
vfsp->vfc_refcount++;
mp->mnt_stat.f_type = vfsp->vfc_typenum;
mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
strlcpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
mp->mnt_vnodecovered = vp;
mp->mnt_cred = crdup(td->td_ucred);
mp->mnt_stat.f_owner = td->td_ucred->cr_uid;
strlcpy(mp->mnt_stat.f_mntonname, fspath, MNAMELEN);
mp->mnt_iosize_max = DFLTPHYS;
#ifdef MAC
mac_init_mount(mp);
mac_create_mount(td->td_ucred, mp);
#endif
*mpp = mp;
return (0);
}
/*
* Destroy the mount struct previously allocated by vfs_mount_alloc().
*/
void
vfs_mount_destroy(struct mount *mp, struct thread *td)
{
mp->mnt_vfc->vfc_refcount--;
if (!TAILQ_EMPTY(&mp->mnt_nvnodelist))
panic("unmount: dangling vnode");
vfs_unbusy(mp,td);
lockdestroy(&mp->mnt_lock);
mtx_destroy(&mp->mnt_mtx);
if (mp->mnt_kern_flag & MNTK_MWAIT)
wakeup(mp);
#ifdef MAC
mac_destroy_mount(mp);
#endif
if (mp->mnt_opt != NULL)
vfs_freeopts(mp->mnt_opt);
crfree(mp->mnt_cred);
free(mp, M_MOUNT);
}
static int
vfs_donmount(struct thread *td, int fsflags, struct uio *fsoptions)
{
struct vfsoptlist *optlist;
char *fstype, *fspath;
int error, fstypelen, fspathlen;
error = vfs_buildopts(fsoptions, &optlist);
if (error)
return (error);
/*
* We need these two options before the others,
* and they are mandatory for any filesystem.
* Ensure they are NUL terminated as well.
*/
fstypelen = 0;
error = vfs_getopt(optlist, "fstype", (void **)&fstype, &fstypelen);
if (error || fstype[fstypelen - 1] != '\0') {
error = EINVAL;
goto bail;
}
fspathlen = 0;
error = vfs_getopt(optlist, "fspath", (void **)&fspath, &fspathlen);
if (error || fspath[fspathlen - 1] != '\0') {
error = EINVAL;
goto bail;
}
/*
* Be ultra-paranoid about making sure the type and fspath
* variables will fit in our mp buffers, including the
* terminating NUL.
*/
if (fstypelen >= MFSNAMELEN - 1 || fspathlen >= MNAMELEN - 1) {
error = ENAMETOOLONG;
goto bail;
}
error = vfs_domount(td, fstype, fspath, fsflags, optlist, 0);
bail:
if (error)
vfs_freeopts(optlist);
return (error);
}
/*
* Old mount API.
*/
#ifndef _SYS_SYSPROTO_H_
struct mount_args {
char *type;
char *path;
int flags;
caddr_t data;
};
#endif
/* ARGSUSED */
int
mount(td, uap)
struct thread *td;
struct mount_args /* {
char *type;
char *path;
int flags;
caddr_t data;
} */ *uap;
{
char *fstype;
char *fspath;
int error;
fstype = malloc(MFSNAMELEN, M_TEMP, M_WAITOK);
fspath = malloc(MNAMELEN, M_TEMP, M_WAITOK);
/*
* vfs_mount() actually takes a kernel string for `type' and
* `path' now, so extract them.
*/
error = copyinstr(uap->type, fstype, MFSNAMELEN, NULL);
if (error == 0)
error = copyinstr(uap->path, fspath, MNAMELEN, NULL);
if (error == 0)
error = vfs_domount(td, fstype, fspath, uap->flags,
uap->data, 1);
free(fstype, M_TEMP);
free(fspath, M_TEMP);
return (error);
}
/*
* vfs_mount(): actually attempt a filesystem mount.
*
* This routine is designed to be a "generic" entry point for routines
* that wish to mount a filesystem. All parameters except `fsdata' are
* pointers into kernel space. `fsdata' is currently still a pointer
* into userspace.
*/
int
vfs_mount(td, fstype, fspath, fsflags, fsdata)
struct thread *td;
const char *fstype;
char *fspath;
int fsflags;
void *fsdata;
{
return (vfs_domount(td, fstype, fspath, fsflags, fsdata, 1));
}
/*
* vfs_domount(): actually attempt a filesystem mount.
*/
static int
vfs_domount(
struct thread *td, /* Flags common to all filesystems. */
const char *fstype, /* Filesystem type. */
char *fspath, /* Mount path. */
int fsflags, /* Flags common to all filesystems. */
void *fsdata, /* Options local to the filesystem. */
int compat /* Invocation from compat syscall. */
)
{
linker_file_t lf;
struct vnode *vp;
struct mount *mp;
struct vfsconf *vfsp;
int error, flag = 0, kern_flag = 0;
struct vattr va;
struct nameidata nd;
/*
* Be ultra-paranoid about making sure the type and fspath
* variables will fit in our mp buffers, including the
* terminating NUL.
*/
if (strlen(fstype) >= MFSNAMELEN || strlen(fspath) >= MNAMELEN)
return (ENAMETOOLONG);
if (jailed(td->td_ucred))
return (EPERM);
if (usermount == 0) {
if ((error = suser(td)) != 0)
return (error);
}
/*
* Do not allow NFS export or MNT_SUIDDIR by unprivileged users.
*/
if (fsflags & (MNT_EXPORTED | MNT_SUIDDIR)) {
if ((error = suser(td)) != 0)
return (error);
}
/*
* Silently enforce MNT_NODEV, MNT_NOSUID and MNT_USER for
* unprivileged users.
*/
if (suser(td) != 0)
fsflags |= MNT_NODEV | MNT_NOSUID | MNT_USER;
/*
* Get vnode to be covered
*/
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, fspath, td);
if ((error = namei(&nd)) != 0)
return (error);
NDFREE(&nd, NDF_ONLY_PNBUF);
vp = nd.ni_vp;
if (fsflags & MNT_UPDATE) {
if ((vp->v_vflag & VV_ROOT) == 0) {
vput(vp);
return (EINVAL);
}
mp = vp->v_mount;
flag = mp->mnt_flag;
kern_flag = mp->mnt_kern_flag;
/*
* We only allow the filesystem to be reloaded if it
* is currently mounted read-only.
*/
if ((fsflags & MNT_RELOAD) &&
((mp->mnt_flag & MNT_RDONLY) == 0)) {
vput(vp);
return (EOPNOTSUPP); /* Needs translation */
}
/*
* Only privileged root, or (if MNT_USER is set) the user that
* did the original mount is permitted to update it.
*/
error = vfs_suser(mp, td);
if (error) {
vput(vp);
return (error);
}
if (vfs_busy(mp, LK_NOWAIT, 0, td)) {
vput(vp);
return (EBUSY);
}
VI_LOCK(vp);
if ((vp->v_iflag & VI_MOUNT) != 0 ||
vp->v_mountedhere != NULL) {
VI_UNLOCK(vp);
vfs_unbusy(mp, td);
vput(vp);
return (EBUSY);
}
vp->v_iflag |= VI_MOUNT;
VI_UNLOCK(vp);
mp->mnt_flag |= fsflags &
(MNT_RELOAD | MNT_FORCE | MNT_UPDATE | MNT_SNAPSHOT);
VOP_UNLOCK(vp, 0, td);
if (compat == 0) {
mp->mnt_optnew = fsdata;
vfs_mergeopts(mp->mnt_optnew, mp->mnt_opt);
}
} else {
/*
* If the user is not root, ensure that they own the directory
* onto which we are attempting to mount.
*/
error = VOP_GETATTR(vp, &va, td->td_ucred, td);
if (error) {
vput(vp);
return (error);
}
if (va.va_uid != td->td_ucred->cr_uid) {
if ((error = suser(td)) != 0) {
vput(vp);
return (error);
}
}
if ((error = vinvalbuf(vp, V_SAVE, td->td_ucred, td, 0, 0)) != 0) {
vput(vp);
return (error);
}
if (vp->v_type != VDIR) {
vput(vp);
return (ENOTDIR);
}
vfsp = vfs_byname(fstype);
if (vfsp == NULL) {
/* Only load modules for root (very important!). */
if ((error = suser(td)) != 0) {
vput(vp);
return (error);
}
error = securelevel_gt(td->td_ucred, 0);
if (error) {
vput(vp);
return (error);
}
error = linker_load_module(NULL, fstype, NULL, NULL, &lf);
if (error || lf == NULL) {
vput(vp);
if (lf == NULL)
error = ENODEV;
return (error);
}
lf->userrefs++;
/* Look up again to see if the VFS was loaded. */
vfsp = vfs_byname(fstype);
if (vfsp == NULL) {
lf->userrefs--;
linker_file_unload(lf, LINKER_UNLOAD_FORCE);
vput(vp);
return (ENODEV);
}
}
VI_LOCK(vp);
if ((vp->v_iflag & VI_MOUNT) != 0 ||
vp->v_mountedhere != NULL) {
VI_UNLOCK(vp);
vput(vp);
return (EBUSY);
}
vp->v_iflag |= VI_MOUNT;
VI_UNLOCK(vp);
/*
* Allocate and initialize the filesystem.
*/
error = vfs_mount_alloc(vp, vfsp, fspath, td, &mp);
if (error) {
vput(vp);
return (error);
}
VOP_UNLOCK(vp, 0, td);
/* XXXMAC: pass to vfs_mount_alloc? */
if (compat == 0)
mp->mnt_optnew = fsdata;
}
/*
* Check if the fs implements the type VFS_[O]MOUNT()
* function we are looking for.
*/
if ((compat == 0) == (mp->mnt_op->vfs_omount != NULL)) {
printf("%s doesn't support the %s mount syscall\n",
mp->mnt_vfc->vfc_name, compat ? "old" : "new");
VI_LOCK(vp);
vp->v_iflag &= ~VI_MOUNT;
VI_UNLOCK(vp);
if (mp->mnt_flag & MNT_UPDATE)
vfs_unbusy(mp, td);
else
vfs_mount_destroy(mp, td);
vrele(vp);
return (EOPNOTSUPP);
}
/*
* Set the mount level flags.
*/
if (fsflags & MNT_RDONLY)
mp->mnt_flag |= MNT_RDONLY;
else if (mp->mnt_flag & MNT_RDONLY)
mp->mnt_kern_flag |= MNTK_WANTRDWR;
mp->mnt_flag &=~ MNT_UPDATEMASK;
mp->mnt_flag |= fsflags & (MNT_UPDATEMASK | MNT_FORCE);
/*
* Mount the filesystem.
* XXX The final recipients of VFS_MOUNT just overwrite the ndp they
* get. No freeing of cn_pnbuf.
*/
if (compat)
error = VFS_OMOUNT(mp, fspath, fsdata, td);
else
error = VFS_MOUNT(mp, td);
if (!error) {
if (mp->mnt_opt != NULL)
vfs_freeopts(mp->mnt_opt);
mp->mnt_opt = mp->mnt_optnew;
}
/*
* Prevent external consumers of mount options from reading
* mnt_optnew.
*/
mp->mnt_optnew = NULL;
if (mp->mnt_flag & MNT_UPDATE) {
if (mp->mnt_kern_flag & MNTK_WANTRDWR)
mp->mnt_flag &= ~MNT_RDONLY;
mp->mnt_flag &=
~(MNT_UPDATE | MNT_RELOAD | MNT_FORCE | MNT_SNAPSHOT);
mp->mnt_kern_flag &= ~MNTK_WANTRDWR;
if (error) {
mp->mnt_flag = flag;
mp->mnt_kern_flag = kern_flag;
}
if ((mp->mnt_flag & MNT_RDONLY) == 0) {
if (mp->mnt_syncer == NULL)
error = vfs_allocate_syncvnode(mp);
} else {
if (mp->mnt_syncer != NULL)
vrele(mp->mnt_syncer);
mp->mnt_syncer = NULL;
}
vfs_unbusy(mp, td);
VI_LOCK(vp);
vp->v_iflag &= ~VI_MOUNT;
VI_UNLOCK(vp);
vrele(vp);
return (error);
}
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
/*
* Put the new filesystem on the mount list after root.
*/
cache_purge(vp);
if (!error) {
struct vnode *newdp;
VI_LOCK(vp);
vp->v_iflag &= ~VI_MOUNT;
VI_UNLOCK(vp);
vp->v_mountedhere = mp;
mtx_lock(&mountlist_mtx);
TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
mtx_unlock(&mountlist_mtx);
vfs_event_signal(NULL, VQ_MOUNT, 0);
if (VFS_ROOT(mp, &newdp, td))
panic("mount: lost mount");
checkdirs(vp, newdp);
vput(newdp);
VOP_UNLOCK(vp, 0, td);
if ((mp->mnt_flag & MNT_RDONLY) == 0)
error = vfs_allocate_syncvnode(mp);
vfs_unbusy(mp, td);
if (error || (error = VFS_START(mp, 0, td)) != 0)
vrele(vp);
} else {
VI_LOCK(vp);
vp->v_iflag &= ~VI_MOUNT;
VI_UNLOCK(vp);
vfs_mount_destroy(mp, td);
vput(vp);
}
return (error);
}
/*
* Scan all active processes to see if any of them have a current
* or root directory of `olddp'. If so, replace them with the new
* mount point.
*/
static void
checkdirs(olddp, newdp)
struct vnode *olddp, *newdp;
{
struct filedesc *fdp;
struct proc *p;
int nrele;
if (vrefcnt(olddp) == 1)
return;
sx_slock(&allproc_lock);
LIST_FOREACH(p, &allproc, p_list) {
mtx_lock(&fdesc_mtx);
fdp = p->p_fd;
if (fdp == NULL) {
mtx_unlock(&fdesc_mtx);
continue;
}
nrele = 0;
FILEDESC_LOCK(fdp);
if (fdp->fd_cdir == olddp) {
VREF(newdp);
fdp->fd_cdir = newdp;
nrele++;
}
if (fdp->fd_rdir == olddp) {
VREF(newdp);
fdp->fd_rdir = newdp;
nrele++;
}
FILEDESC_UNLOCK(fdp);
mtx_unlock(&fdesc_mtx);
while (nrele--)
vrele(olddp);
}
sx_sunlock(&allproc_lock);
if (rootvnode == olddp) {
vrele(rootvnode);
VREF(newdp);
rootvnode = newdp;
}
}
/*
* Unmount a filesystem.
*
* Note: unmount takes a path to the vnode mounted on as argument,
* not special file (as before).
*/
#ifndef _SYS_SYSPROTO_H_
struct unmount_args {
char *path;
int flags;
};
#endif
/* ARGSUSED */
int
unmount(td, uap)
struct thread *td;
register struct unmount_args /* {
char *path;
int flags;
} */ *uap;
{
struct mount *mp;
char *pathbuf;
int error, id0, id1;
if (jailed(td->td_ucred))
return (EPERM);
if (usermount == 0) {
if ((error = suser(td)) != 0)
return (error);
}
pathbuf = malloc(MNAMELEN, M_TEMP, M_WAITOK);
error = copyinstr(uap->path, pathbuf, MNAMELEN, NULL);
if (error) {
free(pathbuf, M_TEMP);
return (error);
}
if (uap->flags & MNT_BYFSID) {
/* Decode the filesystem ID. */
if (sscanf(pathbuf, "FSID:%d:%d", &id0, &id1) != 2) {
free(pathbuf, M_TEMP);
return (EINVAL);
}
mtx_lock(&mountlist_mtx);
TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
if (mp->mnt_stat.f_fsid.val[0] == id0 &&
mp->mnt_stat.f_fsid.val[1] == id1)
break;
}
mtx_unlock(&mountlist_mtx);
} else {
mtx_lock(&mountlist_mtx);
TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
if (strcmp(mp->mnt_stat.f_mntonname, pathbuf) == 0)
break;
}
mtx_unlock(&mountlist_mtx);
}
free(pathbuf, M_TEMP);
if (mp == NULL) {
/*
* Previously we returned ENOENT for a nonexistent path and
* EINVAL for a non-mountpoint. We cannot tell these apart
* now, so in the !MNT_BYFSID case return the more likely
* EINVAL for compatibility.
*/
return ((uap->flags & MNT_BYFSID) ? ENOENT : EINVAL);
}
/*
* Only privileged root, or (if MNT_USER is set) the user that did the
* original mount is permitted to unmount this filesystem.
*/
error = vfs_suser(mp, td);
if (error)
return (error);
/*
* Don't allow unmounting the root filesystem.
*/
if (mp->mnt_flag & MNT_ROOTFS)
return (EINVAL);
return (dounmount(mp, uap->flags, td));
}
/*
* Do the actual filesystem unmount.
*/
int
dounmount(mp, flags, td)
struct mount *mp;
int flags;
struct thread *td;
{
struct vnode *coveredvp, *fsrootvp;
int error;
int async_flag;
mtx_lock(&mountlist_mtx);
if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
mtx_unlock(&mountlist_mtx);
return (EBUSY);
}
mp->mnt_kern_flag |= MNTK_UNMOUNT;
/* Allow filesystems to detect that a forced unmount is in progress. */
if (flags & MNT_FORCE)
mp->mnt_kern_flag |= MNTK_UNMOUNTF;
error = lockmgr(&mp->mnt_lock, LK_DRAIN | LK_INTERLOCK |
((flags & MNT_FORCE) ? 0 : LK_NOWAIT), &mountlist_mtx, td);
if (error) {
mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
if (mp->mnt_kern_flag & MNTK_MWAIT)
wakeup(mp);
return (error);
}
vn_start_write(NULL, &mp, V_WAIT);
if (mp->mnt_flag & MNT_EXPUBLIC)
vfs_setpublicfs(NULL, NULL, NULL);
vfs_msync(mp, MNT_WAIT);
async_flag = mp->mnt_flag & MNT_ASYNC;
mp->mnt_flag &= ~MNT_ASYNC;
cache_purgevfs(mp); /* remove cache entries for this file sys */
if (mp->mnt_syncer != NULL)
vrele(mp->mnt_syncer);
/*
* For forced unmounts, move process cdir/rdir refs on the fs root
* vnode to the covered vnode. For non-forced unmounts we want
* such references to cause an EBUSY error.
*/
if ((flags & MNT_FORCE) && VFS_ROOT(mp, &fsrootvp, td) == 0) {
if (mp->mnt_vnodecovered != NULL)
checkdirs(fsrootvp, mp->mnt_vnodecovered);
if (fsrootvp == rootvnode) {
vrele(rootvnode);
rootvnode = NULL;
}
vput(fsrootvp);
}
if (((mp->mnt_flag & MNT_RDONLY) ||
(error = VFS_SYNC(mp, MNT_WAIT, td->td_ucred, td)) == 0) ||
(flags & MNT_FORCE)) {
error = VFS_UNMOUNT(mp, flags, td);
}
vn_finished_write(mp);
if (error) {
/* Undo cdir/rdir and rootvnode changes made above. */
if ((flags & MNT_FORCE) && VFS_ROOT(mp, &fsrootvp, td) == 0) {
if (mp->mnt_vnodecovered != NULL)
checkdirs(mp->mnt_vnodecovered, fsrootvp);
if (rootvnode == NULL) {
rootvnode = fsrootvp;
vref(rootvnode);
}
vput(fsrootvp);
}
if ((mp->mnt_flag & MNT_RDONLY) == 0 && mp->mnt_syncer == NULL)
(void) vfs_allocate_syncvnode(mp);
mtx_lock(&mountlist_mtx);
mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
mp->mnt_flag |= async_flag;
lockmgr(&mp->mnt_lock, LK_RELEASE | LK_INTERLOCK,
&mountlist_mtx, td);
if (mp->mnt_kern_flag & MNTK_MWAIT)
wakeup(mp);
return (error);
}
mtx_lock(&mountlist_mtx);
TAILQ_REMOVE(&mountlist, mp, mnt_list);
if ((coveredvp = mp->mnt_vnodecovered) != NULL)
coveredvp->v_mountedhere = NULL;
mtx_unlock(&mountlist_mtx);
vfs_event_signal(NULL, VQ_UNMOUNT, 0);
vfs_mount_destroy(mp, td);
if (coveredvp != NULL)
vrele(coveredvp);
return (0);
}
/*
* Lookup a filesystem type, and if found allocate and initialize
* a mount structure for it.
*
* Devname is usually updated by mount(8) after booting.
*/
int
vfs_rootmountalloc(fstypename, devname, mpp)
char *fstypename;
char *devname;
struct mount **mpp;
{
struct thread *td = curthread; /* XXX */
struct vfsconf *vfsp;
struct mount *mp;
int error;
if (fstypename == NULL)
return (ENODEV);
vfsp = vfs_byname(fstypename);
if (vfsp == NULL)
return (ENODEV);
error = vfs_mount_alloc(NULLVP, vfsp, "/", td, &mp);
if (error)
return (error);
mp->mnt_flag |= MNT_RDONLY | MNT_ROOTFS;
strlcpy(mp->mnt_stat.f_mntfromname, devname, MNAMELEN);
*mpp = mp;
return (0);
}
/*
* Find and mount the root filesystem
*/
void
vfs_mountroot(void)
{
char *cp;
int error, i, asked = 0;
/*
* Wait for GEOM to settle down
*/
g_waitidle();
/*
* We are booted with instructions to prompt for the root filesystem.
*/
if (boothowto & RB_ASKNAME) {
if (!vfs_mountroot_ask())
return;
asked = 1;
}
/*
* 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))
return;
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]))
return;
}
}
/*
* 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) {
error = vfs_mountroot_try(cp);
freeenv(cp);
if (!error)
return;
}
/*
* Try values that may have been computed by code during boot
*/
if (!vfs_mountroot_try(rootdevnames[0]))
return;
if (!vfs_mountroot_try(rootdevnames[1]))
return;
/*
* If we (still) have a compiled-in default, try it.
*/
if (ctrootdevname != NULL)
if (!vfs_mountroot_try(ctrootdevname))
return;
/*
* Everything so far has failed, prompt on the console if we haven't
* already tried that.
*/
if (!asked)
if (!vfs_mountroot_ask())
return;
panic("Root mount failed, startup aborted.");
}
/*
* Mount (mountfrom) as the root filesystem.
*/
static int
vfs_mountroot_try(const char *mountfrom)
{
struct mount *mp;
char *vfsname, *path;
const char *devname;
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;
}
/*
* do our best to set rootdev
* XXX: This does not belong here!
*/
if (path[0] != '\0') {
struct cdev *diskdev;
diskdev = getdiskbyname(path);
if (diskdev != NULL)
rootdev = diskdev;
else
printf("setrootbyname failed\n");
}
/* If the root device is a type "memory disk", mount RW */
if (rootdev != NULL && devsw(rootdev) != NULL) {
devname = devtoname(rootdev);
if (devname[0] == 'm' && devname[1] == 'd')
mp->mnt_flag &= ~MNT_RDONLY;
}
error = VFS_OMOUNT(mp, 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_mount_destroy(mp, curthread);
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 fs timestamp */
inittodr(mp->mnt_time);
vfs_unbusy(mp, curthread);
error = VFS_START(mp, 0, curthread);
}
return (error);
}
/*
* Spin prompting on the console for a suitable root filesystem
*/
static int
vfs_mountroot_ask(void)
{
char name[128];
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:/dev/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("\nList of GEOM managed disk devices:\n ");
g_dev_print();
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 cdev pointer of the device, which is probably
* but not by definition, a disk. Mount a DEVFS (on nothing), look the name
* up, extract the cdev from the vnode and unmount it again. Unfortunately
* we cannot use the vnode directly (because we unmount the DEVFS again)
* so the filesystems still have to do the bdevvp() stunt.
*/
struct cdev *
getdiskbyname(char *name)
{
char *cp = name;
struct cdev *dev = NULL;
struct thread *td = curthread;
struct vfsconf *vfsp;
struct mount *mp = NULL;
struct vnode *vroot = NULL;
struct nameidata nid;
int error;
if (!bcmp(cp, "/dev/", 5))
cp += 5;
do {
vfsp = vfs_byname("devfs");
if (vfsp == NULL)
break;
error = vfs_mount_alloc(NULLVP, vfsp, "/dev", td, &mp);
if (error)
break;
mp->mnt_flag |= MNT_RDONLY;
error = VFS_MOUNT(mp, curthread);
if (error)
break;
VFS_START(mp, 0, td);
VFS_ROOT(mp, &vroot, td);
VOP_UNLOCK(vroot, 0, td);
NDINIT(&nid, LOOKUP, NOCACHE|FOLLOW,
UIO_SYSSPACE, cp, curthread);
nid.ni_startdir = vroot;
nid.ni_pathlen = strlen(cp);
nid.ni_cnd.cn_cred = curthread->td_ucred;
nid.ni_cnd.cn_nameptr = cp;
error = lookup(&nid);
if (error)
break;
dev = vn_todev (nid.ni_vp);
NDFREE(&nid, 0);
} while (0);
if (vroot != NULL)
VFS_UNMOUNT(mp, 0, td);
if (mp != NULL)
vfs_mount_destroy(mp, td);
return (dev);
}
/* Show the struct cdev *for a disk specified by name */
#ifdef DDB
DB_SHOW_COMMAND(disk, db_getdiskbyname)
{
struct cdev *dev;
if (modif[0] == '\0') {
db_error("usage: show disk/devicename");
return;
}
dev = getdiskbyname(modif);
if (dev != NULL)
db_printf("struct cdev *= %p\n", dev);
else
db_printf("No disk device matched.\n");
}
#endif
/*
* Get a mount option by its name.
*
* Return 0 if the option was found, ENOENT otherwise.
* If len is non-NULL it will be filled with the length
* of the option. If buf is non-NULL, it will be filled
* with the address of the option.
*/
int
vfs_getopt(opts, name, buf, len)
struct vfsoptlist *opts;
const char *name;
void **buf;
int *len;
{
struct vfsopt *opt;
KASSERT(opts != NULL, ("vfs_getopt: caller passed 'opts' as NULL"));
TAILQ_FOREACH(opt, opts, link) {
if (strcmp(name, opt->name) == 0) {
if (len != NULL)
*len = opt->len;
if (buf != NULL)
*buf = opt->value;
return (0);
}
}
return (ENOENT);
}
/*
* Find and copy a mount option.
*
* The size of the buffer has to be specified
* in len, if it is not the same length as the
* mount option, EINVAL is returned.
* Returns ENOENT if the option is not found.
*/
int
vfs_copyopt(opts, name, dest, len)
struct vfsoptlist *opts;
const char *name;
void *dest;
int len;
{
struct vfsopt *opt;
KASSERT(opts != NULL, ("vfs_copyopt: caller passed 'opts' as NULL"));
TAILQ_FOREACH(opt, opts, link) {
if (strcmp(name, opt->name) == 0) {
if (len != opt->len)
return (EINVAL);
bcopy(opt->value, dest, opt->len);
return (0);
}
}
return (ENOENT);
}
/*
* This is a helper function for filesystems to traverse their
* vnodes. See MNT_VNODE_FOREACH() in sys/mount.h
*/
struct vnode *
__mnt_vnode_next(struct vnode **nvp, struct mount *mp)
{
struct vnode *vp;
mtx_assert(&mp->mnt_mtx, MA_OWNED);
vp = *nvp;
/* Check if we are done */
if (vp == NULL)
return (NULL);
/* If our next vnode is no longer ours, start over */
if (vp->v_mount != mp)
vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
/* Save pointer to next vnode in list */
if (vp != NULL)
*nvp = TAILQ_NEXT(vp, v_nmntvnodes);
else
*nvp = NULL;
return (vp);
}