Reviewed by: jlemon

An initial tidyup of the mount() syscall and VFS mount code.

This code replaces the earlier work done by jlemon in an attempt to
make linux_mount() work.

* the guts of the mount work has been moved into vfs_mount().

* move `type', `path' and `flags' from being userland variables into being
  kernel variables in vfs_mount(). `data' remains a pointer into
  userspace.

* Attempt to verify the `type' and `path' strings passed to vfs_mount()
  aren't too long.

* rework mount() and linux_mount() to take the userland parameters
  (besides data, as mentioned) and pass kernel variables to vfs_mount().
  (linux_mount() already did this, I've just tidied it up a little more.)

* remove the copyin*() stuff for `path'. `data' still requires copyin*()
  since its a pointer into userland.

* set `mount->mnt_statf_mntonname' in vfs_mount() rather than in each
  filesystem.  This variable is generally initialised with `path', and
  each filesystem can override it if they want to.

* NOTE: f_mntonname is intiailised with "/" in the case of a root mount.

sys/compat/linprocfs/linprocfs_vfsops.c

@@ -90,9 +90,6 @@ linprocfs_mount(mp, path, data, ndp, p)
 	mp->mnt_data = 0;
 	vfs_getnewfsid(mp);
 
-	(void) copyinstr(path, (caddr_t)mp->mnt_stat.f_mntonname, MNAMELEN, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
-
 	size = sizeof("linprocfs") - 1;
 	bcopy("linprocfs", mp->mnt_stat.f_mntfromname, size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/compat/linux/linux_file.c

@@ -901,14 +901,16 @@ linux_pwrite(p, uap)
 int
 linux_mount(struct proc *p, struct linux_mount_args *args)
 {
-	struct mount_args bsd_args;
 	struct ufs_args ufs;
         char fstypename[MFSNAMELEN];
         char mntonname[MNAMELEN], mntfromname[MNAMELEN];
-	int error = 0;
+	int error;
+	int fsflags;
+	const char *fstype;
+	void *fsdata;
 
-        error = copyinstr(args->filesystemtype, fstypename, 
+        error = copyinstr(args->filesystemtype, fstypename, MFSNAMELEN - 1,
-	    MFSNAMELEN - 1, NULL);
+	    NULL);
 	if (error)
                 return (error);
         error = copyinstr(args->specialfile, mntfromname, MFSNAMELEN - 1, NULL);
@@ -925,22 +927,21 @@ linux_mount(struct proc *p, struct linux_mount_args *args)
 #endif
 
 	if (strcmp(fstypename, "ext2") == 0) {
-		bsd_args.type = "ext2fs";
+		fstype = "ext2fs";
-		bsd_args.data = (void *)&ufs;
+		fsdata = &ufs;
 		ufs.fspec = mntfromname;
 #define DEFAULT_ROOTID		-2
 		ufs.export.ex_root = DEFAULT_ROOTID;
 		ufs.export.ex_flags =
 		    args->rwflag & LINUX_MS_RDONLY ? MNT_EXRDONLY : 0;
 	} else if (strcmp(fstypename, "proc") == 0) {
-		bsd_args.type = "linprocfs";
+		fstype = "linprocfs";
-		bsd_args.data = NULL;
+		fsdata = NULL;
 	} else {
 		return (ENODEV);
 	}
 
-	bsd_args.path = mntonname;
+	fsflags = 0;
-	bsd_args.flags = 0;
 
 	if ((args->rwflag & 0xffff0000) == 0xc0ed0000) {
 		/*
@@ -948,18 +949,18 @@ linux_mount(struct proc *p, struct linux_mount_args *args)
 		 * FreeBSD has is !ASYNC, which is our default.
 		 */
 		if (args->rwflag & LINUX_MS_RDONLY)
-			bsd_args.flags |= MNT_RDONLY; 
+			fsflags |= MNT_RDONLY; 
 		if (args->rwflag & LINUX_MS_NOSUID)
-			bsd_args.flags |= MNT_NOSUID; 
+			fsflags |= MNT_NOSUID; 
 		if (args->rwflag & LINUX_MS_NODEV)
-			bsd_args.flags |= MNT_NODEV; 
+			fsflags |= MNT_NODEV; 
 		if (args->rwflag & LINUX_MS_NOEXEC)
-			bsd_args.flags |= MNT_NOEXEC; 
+			fsflags |= MNT_NOEXEC; 
 		if (args->rwflag & LINUX_MS_REMOUNT)
-			bsd_args.flags |= MNT_UPDATE; 
+			fsflags |= MNT_UPDATE; 
 	}
 
-	return (mount1(p, &bsd_args, UIO_SYSSPACE));
+	return (vfs_mount(p, fstype, mntonname, fsflags, fsdata));
 }
 
 int

sys/fs/cd9660/cd9660_vfsops.c

@@ -249,8 +249,6 @@ cd9660_mount(mp, path, data, ndp, p)
 		return error;
 	}
 	imp = VFSTOISOFS(mp);
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
 	    &size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/fs/devfs/devfs_vfsops.c

@@ -67,7 +67,6 @@ devfs_mount(mp, path, data, ndp, p)
 	struct proc *p;
 {
 	int error;
-	size_t size;
 	struct devfs_mount *fmp;
 	struct vnode *rvp;
 
@@ -100,13 +99,6 @@ devfs_mount(mp, path, data, ndp, p)
 	}
 	VOP_UNLOCK(rvp, 0, p);
 
-	if (path != NULL) {
-		(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	} else {
-		strcpy(mp->mnt_stat.f_mntonname, "/");
-		size = 1;
-	}
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	bzero(mp->mnt_stat.f_mntfromname, MNAMELEN);
 	bcopy("devfs", mp->mnt_stat.f_mntfromname, sizeof("devfs"));
 	(void)devfs_statfs(mp, &mp->mnt_stat, p);

sys/fs/fdescfs/fdesc_vfsops.c

@@ -74,7 +74,6 @@ fdesc_mount(mp, path, data, ndp, p)
 	struct proc *p;
 {
 	int error = 0;
-	u_int size;
 	struct fdescmount *fmp;
 	struct vnode *rvp;
 
@@ -98,8 +97,6 @@ fdesc_mount(mp, path, data, ndp, p)
 	mp->mnt_data = (qaddr_t) fmp;
 	vfs_getnewfsid(mp);
 
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	bzero(mp->mnt_stat.f_mntfromname, MNAMELEN);
 	bcopy("fdesc", mp->mnt_stat.f_mntfromname, sizeof("fdesc"));
 	(void)fdesc_statfs(mp, &mp->mnt_stat, p);

sys/fs/hpfs/hpfs_vfsops.c

@@ -272,16 +272,12 @@ hpfs_mount (
 	/*
 	 * Since this is a new mount, we want the names for
 	 * the device and the mount point copied in.  If an
-	 * error occurs,  the mountpoint is discarded by the
+	 * error occurs, the mountpoint is discarded by the
-	 * upper level code.
+	 * upper level code.  Note that vfs_mount() handles
+	 * copying the mountpoint f_mntonname for us, so we
+	 * don't have to do it here unless we want to set it
+	 * to something other than "path" for some rason.
 	 */
-	/* Save "last mounted on" info for mount point (NULL pad)*/
-	copyinstr(	path,				/* mount point*/
-			mp->mnt_stat.f_mntonname,	/* save area*/
-			MNAMELEN - 1,			/* max size*/
-			&size);				/* real size*/
-	bzero( mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
-
 	/* Save "mounted from" info for mount point (NULL pad)*/
 	copyinstr(	args.fspec,			/* device name*/
 			mp->mnt_stat.f_mntfromname,	/* save area*/

sys/fs/msdosfs/msdosfs_vfsops.c

@@ -345,9 +345,6 @@ msdosfs_mount(mp, path, data, ndp, p)
 		msdosfs_unmount(mp, MNT_FORCE, p);
 		return error;
 	}
-
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
 	    &size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/fs/ntfs/ntfs_vfsops.c

@@ -376,16 +376,12 @@ ntfs_mount (
 		/*
 		 * Since this is a new mount, we want the names for
 		 * the device and the mount point copied in.  If an
-		 * error occurs,  the mountpoint is discarded by the
+		 * error occurs, the mountpoint is discarded by the
-		 * upper level code.
+		 * upper level code.  Note that vfs_mount() handles
+		 * copying the mountpoint f_mntonname for us, so we
+		 * don't have to do it here unless we want to set it
+		 * to something other than "path" for some rason.
 		 */
-		/* Save "last mounted on" info for mount point (NULL pad)*/
-		copyinstr(	path,				/* mount point*/
-				mp->mnt_stat.f_mntonname,	/* save area*/
-				MNAMELEN - 1,			/* max size*/
-				&size);				/* real size*/
-		bzero( mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
-
 		/* Save "mounted from" info for mount point (NULL pad)*/
 		copyinstr(	args.fspec,			/* device name*/
 				mp->mnt_stat.f_mntfromname,	/* save area*/

sys/fs/nullfs/null_vfsops.c

@@ -191,8 +191,6 @@ nullfs_mount(mp, path, data, ndp, p)
 	mp->mnt_data = (qaddr_t) xmp;
 	vfs_getnewfsid(mp);
 
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	(void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
 	    &size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/fs/nwfs/nwfs_vfsops.c

@@ -146,7 +146,6 @@ static int nwfs_mount(struct mount *mp, char *path, caddr_t data,
 		      struct nameidata *ndp, struct proc *p)
 {
 	struct nwfs_args args; 	  /* will hold data from mount request */
-	size_t size;
 	int error;
 	struct nwmount *nmp = NULL;
 	struct ncp_conn *conn = NULL;
@@ -198,8 +197,6 @@ static int nwfs_mount(struct mount *mp, char *path, caddr_t data,
 	nmp->m.dir_mode  = (nmp->m.dir_mode &
 			    (S_IRWXU|S_IRWXG|S_IRWXO)) | S_IFDIR;
 	if ((error = nwfs_initnls(nmp)) != 0) goto bad;
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	pc = mp->mnt_stat.f_mntfromname;
 	pe = pc+sizeof(mp->mnt_stat.f_mntfromname);
 	bzero(pc, MNAMELEN);

sys/fs/portalfs/portal_vfsops.c

@@ -133,8 +133,6 @@ portal_mount(mp, path, data, ndp, p)
 	mp->mnt_data = (qaddr_t) fmp;
 	vfs_getnewfsid(mp);
 
-	(void)copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	(void)copyinstr(args.pa_config,
 	    mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/fs/umapfs/umap_vfsops.c

@@ -221,8 +221,6 @@ umapfs_mount(mp, path, data, ndp, p)
 	mp->mnt_data = (qaddr_t) amp;
 	vfs_getnewfsid(mp);
 
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	(void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
 	    &size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/fs/unionfs/union_vfsops.c

@@ -253,9 +253,6 @@ union_mount(mp, path, data, ndp, p)
 	mp->mnt_data = (qaddr_t) um;
 	vfs_getnewfsid(mp);
 
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
-
 	switch (um->um_op) {
 	case UNMNT_ABOVE:
 		cp = "<above>:";

sys/gnu/ext2fs/ext2_vfsops.c

@@ -192,7 +192,11 @@ ext2_mount(mp, path, data, ndp, p)
 	int error, flags;
 	mode_t accessmode;
 
-	if ((error = copyin(data, (caddr_t)&args, sizeof (struct ufs_args))) != 0)
+	/* Double-check the length of path.. */
+	if (strlen(path) >= MAXMNTLEN - 1)
+		return (ENAMETOOLONG);
+	error = copyin(data, (caddr_t)&args, sizeof (struct ufs_args));
+	if (error != 0)
 		return (error);
 	/*
 	 * If updating, check whether changing from read-only to
@@ -308,10 +312,12 @@ ext2_mount(mp, path, data, ndp, p)
 	}
 	ump = VFSTOUFS(mp);
 	fs = ump->um_e2fs;
-	(void) copyinstr(path, fs->fs_fsmnt, sizeof(fs->fs_fsmnt) - 1, &size);
+	/*
-	bzero(fs->fs_fsmnt + size, sizeof(fs->fs_fsmnt) - size);
+	 * Note that this strncpy() is ok because of a check at the start
-	bcopy((caddr_t)fs->fs_fsmnt, (caddr_t)mp->mnt_stat.f_mntonname,
+	 * of ext2_mount().
-	    MNAMELEN);
+	 */
+	strncpy(fs->fs_fsmnt, path, MAXMNTLEN);
+	fs->fs_fsmnt[MAXMNTLEN - 1] = '\0';
 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 
 	    &size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/gnu/fs/ext2fs/ext2_vfsops.c

@@ -192,7 +192,11 @@ ext2_mount(mp, path, data, ndp, p)
 	int error, flags;
 	mode_t accessmode;
 
-	if ((error = copyin(data, (caddr_t)&args, sizeof (struct ufs_args))) != 0)
+	/* Double-check the length of path.. */
+	if (strlen(path) >= MAXMNTLEN - 1)
+		return (ENAMETOOLONG);
+	error = copyin(data, (caddr_t)&args, sizeof (struct ufs_args));
+	if (error != 0)
 		return (error);
 	/*
 	 * If updating, check whether changing from read-only to
@@ -308,10 +312,12 @@ ext2_mount(mp, path, data, ndp, p)
 	}
 	ump = VFSTOUFS(mp);
 	fs = ump->um_e2fs;
-	(void) copyinstr(path, fs->fs_fsmnt, sizeof(fs->fs_fsmnt) - 1, &size);
+	/*
-	bzero(fs->fs_fsmnt + size, sizeof(fs->fs_fsmnt) - size);
+	 * Note that this strncpy() is ok because of a check at the start
-	bcopy((caddr_t)fs->fs_fsmnt, (caddr_t)mp->mnt_stat.f_mntonname,
+	 * of ext2_mount().
-	    MNAMELEN);
+	 */
+	strncpy(fs->fs_fsmnt, path, MAXMNTLEN);
+	fs->fs_fsmnt[MAXMNTLEN - 1] = '\0';
 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 
 	    &size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/isofs/cd9660/cd9660_vfsops.c

@@ -249,8 +249,6 @@ cd9660_mount(mp, path, data, ndp, p)
 		return error;
 	}
 	imp = VFSTOISOFS(mp);
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
 	    &size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/kern/vfs_conf.c

@@ -214,6 +214,14 @@ vfs_mountroot_try(char *mountfrom)
 	    (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, curproc);
 
 done:

sys/kern/vfs_extattr.c

@@ -107,14 +107,6 @@ struct mount_args {
 /* ARGSUSED */
 int
 mount(p, uap)
-	struct proc *p;
-	struct mount_args *uap;
-{
-	return (mount1(p, uap, UIO_USERSPACE));
-}
-
-int
-mount1(p, uap, segflag)
 	struct proc *p;
 	struct mount_args /* {
 		syscallarg(char *) type;
@@ -122,7 +114,47 @@ mount1(p, uap, segflag)
 		syscallarg(int) flags;
 		syscallarg(caddr_t) data;
 	} */ *uap;
-	int segflag;
+{
+	char *fstype;
+	char *fspath;
+	int error;
+
+	fstype = malloc(MFSNAMELEN, M_TEMP, M_WAITOK | M_ZERO);
+	fspath = malloc(MNAMELEN, M_TEMP, M_WAITOK | M_ZERO);
+
+	/*
+	 * vfs_mount() actually takes a kernel string for `type' and
+	 * `path' now, so extract them.
+	 */
+	error = copyinstr(SCARG(uap, type), fstype, MFSNAMELEN, NULL);
+	if (error)
+		goto finish;
+	error = copyinstr(SCARG(uap, path), fspath, MNAMELEN, NULL);
+	if (error)
+		goto finish;
+	error = vfs_mount(p, fstype, fspath, SCARG(uap, flags),
+	    SCARG(uap, data));
+finish:
+	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(p, fstype, fspath, fsflags, fsdata)
+	struct proc *p;
+	char *fstype;
+	char *fspath;
+	int fsflags;
+	void *fsdata;
 {
 	struct vnode *vp;
 	struct mount *mp;
@@ -130,14 +162,22 @@ mount1(p, uap, segflag)
 	int error, flag = 0, flag2 = 0;
 	struct vattr va;
 	struct nameidata nd;
-	char fstypename[MFSNAMELEN];
+
+	/*
+	 * Be ultra-paranoid about making sure the type and fspath
+	 * variables will fit in our mp buffers, including the
+	 * terminating NUL.
+	 */
+	if ((strlen(fstype) >= MNAMELEN - 1) ||
+	    (strlen(fspath) >= MFSNAMELEN - 1))
+		return (ENAMETOOLONG);
 
 	if (usermount == 0 && (error = suser(p)))
 		return (error);
 	/*
 	 * Do not allow NFS export by non-root users.
 	 */
-	if (SCARG(uap, flags) & MNT_EXPORTED) {
+	if (fsflags & MNT_EXPORTED) {
 		error = suser(p);
 		if (error)
 			return (error);
@@ -146,16 +186,16 @@ mount1(p, uap, segflag)
 	 * Silently enforce MNT_NOSUID and MNT_NODEV for non-root users
 	 */
 	if (suser_xxx(p->p_ucred, 0, 0)) 
-		SCARG(uap, flags) |= MNT_NOSUID | MNT_NODEV;
+		fsflags |= MNT_NOSUID | MNT_NODEV;
 	/*
 	 * Get vnode to be covered
 	 */
-	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, segflag, SCARG(uap, path), p);
+	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, fspath, p);
 	if ((error = namei(&nd)) != 0)
 		return (error);
 	NDFREE(&nd, NDF_ONLY_PNBUF);
 	vp = nd.ni_vp;
-	if (SCARG(uap, flags) & MNT_UPDATE) {
+	if (fsflags & MNT_UPDATE) {
 		if ((vp->v_flag & VROOT) == 0) {
 			vput(vp);
 			return (EINVAL);
@@ -167,7 +207,7 @@ mount1(p, uap, segflag)
 		 * We only allow the filesystem to be reloaded if it
 		 * is currently mounted read-only.
 		 */
-		if ((SCARG(uap, flags) & MNT_RELOAD) &&
+		if ((fsflags & MNT_RELOAD) &&
 		    ((mp->mnt_flag & MNT_RDONLY) == 0)) {
 			vput(vp);
 			return (EOPNOTSUPP);	/* Needs translation */
@@ -195,7 +235,7 @@ mount1(p, uap, segflag)
 		}
 		vp->v_flag |= VMOUNT;
 		mtx_unlock(&vp->v_interlock);
-		mp->mnt_flag |= SCARG(uap, flags) &
+		mp->mnt_flag |= fsflags &
 		    (MNT_RELOAD | MNT_FORCE | MNT_UPDATE | MNT_SNAPSHOT);
 		VOP_UNLOCK(vp, 0, p);
 		goto update;
@@ -218,13 +258,8 @@ mount1(p, uap, segflag)
 		vput(vp);
 		return (ENOTDIR);
 	}
-	if ((error = copyinstrfrom(SCARG(uap, type),
-	     fstypename, MFSNAMELEN, NULL, segflag)) != 0) {
-		vput(vp);
-		return (error);
-	}
 	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
-		if (!strcmp(vfsp->vfc_name, fstypename))
+		if (!strcmp(vfsp->vfc_name, fstype))
 			break;
 	if (vfsp == NULL) {
 		linker_file_t lf;
@@ -234,7 +269,7 @@ mount1(p, uap, segflag)
 			vput(vp);
 			return error;
 		}
-		error = linker_load_file(fstypename, &lf);
+		error = linker_load_file(fstype, &lf);
 		if (error || lf == NULL) {
 			vput(vp);
 			if (lf == NULL)
@@ -244,7 +279,7 @@ mount1(p, uap, segflag)
 		lf->userrefs++;
 		/* lookup again, see if the VFS was loaded */
 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
-			if (!strcmp(vfsp->vfc_name, fstypename))
+			if (!strcmp(vfsp->vfc_name, fstype))
 				break;
 		if (vfsp == NULL) {
 			lf->userrefs--;
@@ -274,16 +309,19 @@ mount1(p, uap, segflag)
 	vfsp->vfc_refcount++;
 	mp->mnt_stat.f_type = vfsp->vfc_typenum;
 	mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
-	strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
+	strncpy(mp->mnt_stat.f_fstypename, fstype, MFSNAMELEN);
+	mp->mnt_stat.f_fstypename[MFSNAMELEN - 1] = '\0';
 	mp->mnt_vnodecovered = vp;
 	mp->mnt_stat.f_owner = p->p_ucred->cr_uid;
+	strncpy(mp->mnt_stat.f_mntonname, fspath, MNAMELEN);
+	mp->mnt_stat.f_mntonname[MNAMELEN - 1] = '\0';
 	mp->mnt_iosize_max = DFLTPHYS;
 	VOP_UNLOCK(vp, 0, p);
 update:
 	/*
 	 * Set the mount level flags.
 	 */
-	if (SCARG(uap, flags) & MNT_RDONLY)
+	if (fsflags & MNT_RDONLY)
 		mp->mnt_flag |= MNT_RDONLY;
 	else if (mp->mnt_flag & MNT_RDONLY)
 		mp->mnt_kern_flag |= MNTK_WANTRDWR;
@@ -291,7 +329,7 @@ update:
 	    MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_NOATIME |
 	    MNT_NOSYMFOLLOW | MNT_IGNORE |
 	    MNT_NOCLUSTERR | MNT_NOCLUSTERW | MNT_SUIDDIR);
-	mp->mnt_flag |= SCARG(uap, flags) & (MNT_NOSUID | MNT_NOEXEC |
+	mp->mnt_flag |= fsflags & (MNT_NOSUID | MNT_NOEXEC |
 	    MNT_NODEV | MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_FORCE |
 	    MNT_NOSYMFOLLOW | MNT_IGNORE |
 	    MNT_NOATIME | MNT_NOCLUSTERR | MNT_NOCLUSTERW | MNT_SUIDDIR);
@@ -300,7 +338,7 @@ update:
 	 * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
 	 * get.  No freeing of cn_pnbuf.
 	 */
-	error = VFS_MOUNT(mp, SCARG(uap, path), SCARG(uap, data), &nd, p);
+	error = VFS_MOUNT(mp, fspath, fsdata, &nd, p);
 	if (mp->mnt_flag & MNT_UPDATE) {
 		if (mp->mnt_kern_flag & MNTK_WANTRDWR)
 			mp->mnt_flag &= ~MNT_RDONLY;

sys/kern/vfs_mount.c

@@ -214,6 +214,14 @@ vfs_mountroot_try(char *mountfrom)
 	    (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, curproc);
 
 done:

sys/kern/vfs_syscalls.c

@@ -107,14 +107,6 @@ struct mount_args {
 /* ARGSUSED */
 int
 mount(p, uap)
-	struct proc *p;
-	struct mount_args *uap;
-{
-	return (mount1(p, uap, UIO_USERSPACE));
-}
-
-int
-mount1(p, uap, segflag)
 	struct proc *p;
 	struct mount_args /* {
 		syscallarg(char *) type;
@@ -122,7 +114,47 @@ mount1(p, uap, segflag)
 		syscallarg(int) flags;
 		syscallarg(caddr_t) data;
 	} */ *uap;
-	int segflag;
+{
+	char *fstype;
+	char *fspath;
+	int error;
+
+	fstype = malloc(MFSNAMELEN, M_TEMP, M_WAITOK | M_ZERO);
+	fspath = malloc(MNAMELEN, M_TEMP, M_WAITOK | M_ZERO);
+
+	/*
+	 * vfs_mount() actually takes a kernel string for `type' and
+	 * `path' now, so extract them.
+	 */
+	error = copyinstr(SCARG(uap, type), fstype, MFSNAMELEN, NULL);
+	if (error)
+		goto finish;
+	error = copyinstr(SCARG(uap, path), fspath, MNAMELEN, NULL);
+	if (error)
+		goto finish;
+	error = vfs_mount(p, fstype, fspath, SCARG(uap, flags),
+	    SCARG(uap, data));
+finish:
+	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(p, fstype, fspath, fsflags, fsdata)
+	struct proc *p;
+	char *fstype;
+	char *fspath;
+	int fsflags;
+	void *fsdata;
 {
 	struct vnode *vp;
 	struct mount *mp;
@@ -130,14 +162,22 @@ mount1(p, uap, segflag)
 	int error, flag = 0, flag2 = 0;
 	struct vattr va;
 	struct nameidata nd;
-	char fstypename[MFSNAMELEN];
+
+	/*
+	 * Be ultra-paranoid about making sure the type and fspath
+	 * variables will fit in our mp buffers, including the
+	 * terminating NUL.
+	 */
+	if ((strlen(fstype) >= MNAMELEN - 1) ||
+	    (strlen(fspath) >= MFSNAMELEN - 1))
+		return (ENAMETOOLONG);
 
 	if (usermount == 0 && (error = suser(p)))
 		return (error);
 	/*
 	 * Do not allow NFS export by non-root users.
 	 */
-	if (SCARG(uap, flags) & MNT_EXPORTED) {
+	if (fsflags & MNT_EXPORTED) {
 		error = suser(p);
 		if (error)
 			return (error);
@@ -146,16 +186,16 @@ mount1(p, uap, segflag)
 	 * Silently enforce MNT_NOSUID and MNT_NODEV for non-root users
 	 */
 	if (suser_xxx(p->p_ucred, 0, 0)) 
-		SCARG(uap, flags) |= MNT_NOSUID | MNT_NODEV;
+		fsflags |= MNT_NOSUID | MNT_NODEV;
 	/*
 	 * Get vnode to be covered
 	 */
-	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, segflag, SCARG(uap, path), p);
+	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, fspath, p);
 	if ((error = namei(&nd)) != 0)
 		return (error);
 	NDFREE(&nd, NDF_ONLY_PNBUF);
 	vp = nd.ni_vp;
-	if (SCARG(uap, flags) & MNT_UPDATE) {
+	if (fsflags & MNT_UPDATE) {
 		if ((vp->v_flag & VROOT) == 0) {
 			vput(vp);
 			return (EINVAL);
@@ -167,7 +207,7 @@ mount1(p, uap, segflag)
 		 * We only allow the filesystem to be reloaded if it
 		 * is currently mounted read-only.
 		 */
-		if ((SCARG(uap, flags) & MNT_RELOAD) &&
+		if ((fsflags & MNT_RELOAD) &&
 		    ((mp->mnt_flag & MNT_RDONLY) == 0)) {
 			vput(vp);
 			return (EOPNOTSUPP);	/* Needs translation */
@@ -195,7 +235,7 @@ mount1(p, uap, segflag)
 		}
 		vp->v_flag |= VMOUNT;
 		mtx_unlock(&vp->v_interlock);
-		mp->mnt_flag |= SCARG(uap, flags) &
+		mp->mnt_flag |= fsflags &
 		    (MNT_RELOAD | MNT_FORCE | MNT_UPDATE | MNT_SNAPSHOT);
 		VOP_UNLOCK(vp, 0, p);
 		goto update;
@@ -218,13 +258,8 @@ mount1(p, uap, segflag)
 		vput(vp);
 		return (ENOTDIR);
 	}
-	if ((error = copyinstrfrom(SCARG(uap, type),
-	     fstypename, MFSNAMELEN, NULL, segflag)) != 0) {
-		vput(vp);
-		return (error);
-	}
 	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
-		if (!strcmp(vfsp->vfc_name, fstypename))
+		if (!strcmp(vfsp->vfc_name, fstype))
 			break;
 	if (vfsp == NULL) {
 		linker_file_t lf;
@@ -234,7 +269,7 @@ mount1(p, uap, segflag)
 			vput(vp);
 			return error;
 		}
-		error = linker_load_file(fstypename, &lf);
+		error = linker_load_file(fstype, &lf);
 		if (error || lf == NULL) {
 			vput(vp);
 			if (lf == NULL)
@@ -244,7 +279,7 @@ mount1(p, uap, segflag)
 		lf->userrefs++;
 		/* lookup again, see if the VFS was loaded */
 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
-			if (!strcmp(vfsp->vfc_name, fstypename))
+			if (!strcmp(vfsp->vfc_name, fstype))
 				break;
 		if (vfsp == NULL) {
 			lf->userrefs--;
@@ -274,16 +309,19 @@ mount1(p, uap, segflag)
 	vfsp->vfc_refcount++;
 	mp->mnt_stat.f_type = vfsp->vfc_typenum;
 	mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
-	strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
+	strncpy(mp->mnt_stat.f_fstypename, fstype, MFSNAMELEN);
+	mp->mnt_stat.f_fstypename[MFSNAMELEN - 1] = '\0';
 	mp->mnt_vnodecovered = vp;
 	mp->mnt_stat.f_owner = p->p_ucred->cr_uid;
+	strncpy(mp->mnt_stat.f_mntonname, fspath, MNAMELEN);
+	mp->mnt_stat.f_mntonname[MNAMELEN - 1] = '\0';
 	mp->mnt_iosize_max = DFLTPHYS;
 	VOP_UNLOCK(vp, 0, p);
 update:
 	/*
 	 * Set the mount level flags.
 	 */
-	if (SCARG(uap, flags) & MNT_RDONLY)
+	if (fsflags & MNT_RDONLY)
 		mp->mnt_flag |= MNT_RDONLY;
 	else if (mp->mnt_flag & MNT_RDONLY)
 		mp->mnt_kern_flag |= MNTK_WANTRDWR;
@@ -291,7 +329,7 @@ update:
 	    MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_NOATIME |
 	    MNT_NOSYMFOLLOW | MNT_IGNORE |
 	    MNT_NOCLUSTERR | MNT_NOCLUSTERW | MNT_SUIDDIR);
-	mp->mnt_flag |= SCARG(uap, flags) & (MNT_NOSUID | MNT_NOEXEC |
+	mp->mnt_flag |= fsflags & (MNT_NOSUID | MNT_NOEXEC |
 	    MNT_NODEV | MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_FORCE |
 	    MNT_NOSYMFOLLOW | MNT_IGNORE |
 	    MNT_NOATIME | MNT_NOCLUSTERR | MNT_NOCLUSTERW | MNT_SUIDDIR);
@@ -300,7 +338,7 @@ update:
 	 * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
 	 * get.  No freeing of cn_pnbuf.
 	 */
-	error = VFS_MOUNT(mp, SCARG(uap, path), SCARG(uap, data), &nd, p);
+	error = VFS_MOUNT(mp, fspath, fsdata, &nd, p);
 	if (mp->mnt_flag & MNT_UPDATE) {
 		if (mp->mnt_kern_flag & MNTK_WANTRDWR)
 			mp->mnt_flag &= ~MNT_RDONLY;

sys/miscfs/fdesc/fdesc_vfsops.c

@@ -74,7 +74,6 @@ fdesc_mount(mp, path, data, ndp, p)
 	struct proc *p;
 {
 	int error = 0;
-	u_int size;
 	struct fdescmount *fmp;
 	struct vnode *rvp;
 
@@ -98,8 +97,6 @@ fdesc_mount(mp, path, data, ndp, p)
 	mp->mnt_data = (qaddr_t) fmp;
 	vfs_getnewfsid(mp);
 
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	bzero(mp->mnt_stat.f_mntfromname, MNAMELEN);
 	bcopy("fdesc", mp->mnt_stat.f_mntfromname, sizeof("fdesc"));
 	(void)fdesc_statfs(mp, &mp->mnt_stat, p);

sys/miscfs/nullfs/null_vfsops.c

@@ -191,8 +191,6 @@ nullfs_mount(mp, path, data, ndp, p)
 	mp->mnt_data = (qaddr_t) xmp;
 	vfs_getnewfsid(mp);
 
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	(void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
 	    &size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/miscfs/portal/portal_vfsops.c

@@ -133,8 +133,6 @@ portal_mount(mp, path, data, ndp, p)
 	mp->mnt_data = (qaddr_t) fmp;
 	vfs_getnewfsid(mp);
 
-	(void)copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	(void)copyinstr(args.pa_config,
 	    mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/miscfs/umapfs/umap_vfsops.c

@@ -221,8 +221,6 @@ umapfs_mount(mp, path, data, ndp, p)
 	mp->mnt_data = (qaddr_t) amp;
 	vfs_getnewfsid(mp);
 
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	(void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
 	    &size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/miscfs/union/union_vfsops.c

@@ -253,9 +253,6 @@ union_mount(mp, path, data, ndp, p)
 	mp->mnt_data = (qaddr_t) um;
 	vfs_getnewfsid(mp);
 
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
-
 	switch (um->um_op) {
 	case UNMNT_ABOVE:
 		cp = "<above>:";

sys/msdosfs/msdosfs_vfsops.c

@@ -345,9 +345,6 @@ msdosfs_mount(mp, path, data, ndp, p)
 		msdosfs_unmount(mp, MNT_FORCE, p);
 		return error;
 	}
-
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
 	    &size);
 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);

sys/nfs/nfs_vfsops.c

@@ -764,7 +764,7 @@ nfs_mount(mp, path, data, ndp, p)
 	struct nfs_args args;
 	struct sockaddr *nam;
 	struct vnode *vp;
-	char pth[MNAMELEN], hst[MNAMELEN];
+	char hst[MNAMELEN];
 	size_t len;
 	u_char nfh[NFSX_V3FHMAX];
 
@@ -810,10 +810,6 @@ nfs_mount(mp, path, data, ndp, p)
 	error = copyin((caddr_t)args.fh, (caddr_t)nfh, args.fhsize);
 	if (error)
 		return (error);
-	error = copyinstr(path, pth, MNAMELEN-1, &len);
-	if (error)
-		return (error);
-	bzero(&pth[len], MNAMELEN - len);
 	error = copyinstr(args.hostname, hst, MNAMELEN-1, &len);
 	if (error)
 		return (error);
@@ -823,7 +819,7 @@ nfs_mount(mp, path, data, ndp, p)
 	if (error)
 		return (error);
 	args.fh = nfh;
-	error = mountnfs(&args, mp, nam, pth, hst, &vp);
+	error = mountnfs(&args, mp, nam, path, hst, &vp);
 	return (error);
 }
 

sys/nfsclient/nfs_vfsops.c

@@ -764,7 +764,7 @@ nfs_mount(mp, path, data, ndp, p)
 	struct nfs_args args;
 	struct sockaddr *nam;
 	struct vnode *vp;
-	char pth[MNAMELEN], hst[MNAMELEN];
+	char hst[MNAMELEN];
 	size_t len;
 	u_char nfh[NFSX_V3FHMAX];
 
@@ -810,10 +810,6 @@ nfs_mount(mp, path, data, ndp, p)
 	error = copyin((caddr_t)args.fh, (caddr_t)nfh, args.fhsize);
 	if (error)
 		return (error);
-	error = copyinstr(path, pth, MNAMELEN-1, &len);
-	if (error)
-		return (error);
-	bzero(&pth[len], MNAMELEN - len);
 	error = copyinstr(args.hostname, hst, MNAMELEN-1, &len);
 	if (error)
 		return (error);
@@ -823,7 +819,7 @@ nfs_mount(mp, path, data, ndp, p)
 	if (error)
 		return (error);
 	args.fh = nfh;
-	error = mountnfs(&args, mp, nam, pth, hst, &vp);
+	error = mountnfs(&args, mp, nam, path, hst, &vp);
 	return (error);
 }
 

sys/ntfs/ntfs_vfsops.c

@@ -376,16 +376,12 @@ ntfs_mount (
 		/*
 		 * Since this is a new mount, we want the names for
 		 * the device and the mount point copied in.  If an
-		 * error occurs,  the mountpoint is discarded by the
+		 * error occurs, the mountpoint is discarded by the
-		 * upper level code.
+		 * upper level code.  Note that vfs_mount() handles
+		 * copying the mountpoint f_mntonname for us, so we
+		 * don't have to do it here unless we want to set it
+		 * to something other than "path" for some rason.
 		 */
-		/* Save "last mounted on" info for mount point (NULL pad)*/
-		copyinstr(	path,				/* mount point*/
-				mp->mnt_stat.f_mntonname,	/* save area*/
-				MNAMELEN - 1,			/* max size*/
-				&size);				/* real size*/
-		bzero( mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
-
 		/* Save "mounted from" info for mount point (NULL pad)*/
 		copyinstr(	args.fspec,			/* device name*/
 				mp->mnt_stat.f_mntfromname,	/* save area*/

sys/nwfs/nwfs_vfsops.c

@@ -146,7 +146,6 @@ static int nwfs_mount(struct mount *mp, char *path, caddr_t data,
 		      struct nameidata *ndp, struct proc *p)
 {
 	struct nwfs_args args; 	  /* will hold data from mount request */
-	size_t size;
 	int error;
 	struct nwmount *nmp = NULL;
 	struct ncp_conn *conn = NULL;
@@ -198,8 +197,6 @@ static int nwfs_mount(struct mount *mp, char *path, caddr_t data,
 	nmp->m.dir_mode  = (nmp->m.dir_mode &
 			    (S_IRWXU|S_IRWXG|S_IRWXO)) | S_IFDIR;
 	if ((error = nwfs_initnls(nmp)) != 0) goto bad;
-	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 	pc = mp->mnt_stat.f_mntfromname;
 	pe = pc+sizeof(mp->mnt_stat.f_mntfromname);
 	bzero(pc, MNAMELEN);

sys/sys/mount.h

@@ -404,7 +404,8 @@ extern	char *mountrootfsname;
  * exported vnode operations
  */
 int	dounmount __P((struct mount *, int, struct proc *));
-int	mount1 __P((struct proc *p, struct mount_args *uap, int segflag));
+int	vfs_mount __P((struct proc *p, char *type, char *path, int flags,
+	    void *data));
 int	vfs_setpublicfs			    /* set publicly exported fs */
 	  __P((struct mount *, struct netexport *, struct export_args *));
 int	vfs_lock __P((struct mount *));         /* lock a vfs */

sys/ufs/ffs/ffs_vfsops.c

@@ -323,9 +323,8 @@ ffs_mount(mp, path, data, ndp, p)
 		 * We need the name for the mount point (also used for
 		 * "last mounted on") copied in. If an error occurs,
 		 * the mount point is discarded by the upper level code.
+		 * Note that vfs_mount() populates f_mntonname for us.
 		 */
-		copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
-		bzero( mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 		if ((error = ffs_mountfs(devvp, mp, p, M_FFSNODE)) != 0) {
 			vrele(devvp);
 			return (error);