Home | History | Annotate | Line # | Download | only in common
vfs_syscalls_43.c revision 1.7
      1  1.7      fvdl /*	$NetBSD: vfs_syscalls_43.c,v 1.7 1997/10/10 13:03:32 fvdl Exp $	*/
      2  1.1  christos 
      3  1.1  christos /*
      4  1.1  christos  * Copyright (c) 1989, 1993
      5  1.1  christos  *	The Regents of the University of California.  All rights reserved.
      6  1.1  christos  * (c) UNIX System Laboratories, Inc.
      7  1.1  christos  * All or some portions of this file are derived from material licensed
      8  1.1  christos  * to the University of California by American Telephone and Telegraph
      9  1.1  christos  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
     10  1.1  christos  * the permission of UNIX System Laboratories, Inc.
     11  1.1  christos  *
     12  1.1  christos  * Redistribution and use in source and binary forms, with or without
     13  1.1  christos  * modification, are permitted provided that the following conditions
     14  1.1  christos  * are met:
     15  1.1  christos  * 1. Redistributions of source code must retain the above copyright
     16  1.1  christos  *    notice, this list of conditions and the following disclaimer.
     17  1.1  christos  * 2. Redistributions in binary form must reproduce the above copyright
     18  1.1  christos  *    notice, this list of conditions and the following disclaimer in the
     19  1.1  christos  *    documentation and/or other materials provided with the distribution.
     20  1.1  christos  * 3. All advertising materials mentioning features or use of this software
     21  1.1  christos  *    must display the following acknowledgement:
     22  1.1  christos  *	This product includes software developed by the University of
     23  1.1  christos  *	California, Berkeley and its contributors.
     24  1.1  christos  * 4. Neither the name of the University nor the names of its contributors
     25  1.1  christos  *    may be used to endorse or promote products derived from this software
     26  1.1  christos  *    without specific prior written permission.
     27  1.1  christos  *
     28  1.1  christos  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29  1.1  christos  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30  1.1  christos  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31  1.1  christos  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32  1.1  christos  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33  1.1  christos  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34  1.1  christos  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35  1.1  christos  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36  1.1  christos  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37  1.1  christos  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38  1.1  christos  * SUCH DAMAGE.
     39  1.1  christos  *
     40  1.1  christos  *	@(#)vfs_syscalls.c	8.28 (Berkeley) 12/10/94
     41  1.1  christos  */
     42  1.1  christos 
     43  1.1  christos #include <sys/param.h>
     44  1.1  christos #include <sys/systm.h>
     45  1.1  christos #include <sys/filedesc.h>
     46  1.1  christos #include <sys/kernel.h>
     47  1.1  christos #include <sys/proc.h>
     48  1.1  christos #include <sys/file.h>
     49  1.1  christos #include <sys/vnode.h>
     50  1.1  christos #include <sys/namei.h>
     51  1.1  christos #include <sys/dirent.h>
     52  1.1  christos #include <sys/socket.h>
     53  1.1  christos #include <sys/socketvar.h>
     54  1.1  christos #include <sys/stat.h>
     55  1.1  christos #include <sys/ioctl.h>
     56  1.1  christos #include <sys/fcntl.h>
     57  1.1  christos #include <sys/malloc.h>
     58  1.1  christos #include <sys/syslog.h>
     59  1.1  christos #include <sys/unistd.h>
     60  1.1  christos #include <sys/resourcevar.h>
     61  1.1  christos 
     62  1.1  christos #include <sys/mount.h>
     63  1.1  christos #include <sys/syscallargs.h>
     64  1.1  christos 
     65  1.4  christos static void cvtstat __P((struct stat *, struct ostat *));
     66  1.4  christos 
     67  1.1  christos /*
     68  1.1  christos  * Convert from an old to a new stat structure.
     69  1.1  christos  */
     70  1.4  christos static void
     71  1.1  christos cvtstat(st, ost)
     72  1.1  christos 	struct stat *st;
     73  1.1  christos 	struct ostat *ost;
     74  1.1  christos {
     75  1.1  christos 
     76  1.1  christos 	ost->st_dev = st->st_dev;
     77  1.1  christos 	ost->st_ino = st->st_ino;
     78  1.1  christos 	ost->st_mode = st->st_mode;
     79  1.1  christos 	ost->st_nlink = st->st_nlink;
     80  1.1  christos 	ost->st_uid = st->st_uid;
     81  1.1  christos 	ost->st_gid = st->st_gid;
     82  1.1  christos 	ost->st_rdev = st->st_rdev;
     83  1.1  christos 	if (st->st_size < (quad_t)1 << 32)
     84  1.1  christos 		ost->st_size = st->st_size;
     85  1.1  christos 	else
     86  1.1  christos 		ost->st_size = -2;
     87  1.1  christos 	ost->st_atime = st->st_atime;
     88  1.1  christos 	ost->st_mtime = st->st_mtime;
     89  1.1  christos 	ost->st_ctime = st->st_ctime;
     90  1.1  christos 	ost->st_blksize = st->st_blksize;
     91  1.1  christos 	ost->st_blocks = st->st_blocks;
     92  1.1  christos 	ost->st_flags = st->st_flags;
     93  1.1  christos 	ost->st_gen = st->st_gen;
     94  1.1  christos }
     95  1.1  christos 
     96  1.1  christos /*
     97  1.1  christos  * Get file status; this version follows links.
     98  1.1  christos  */
     99  1.1  christos /* ARGSUSED */
    100  1.1  christos int
    101  1.3   mycroft compat_43_sys_stat(p, v, retval)
    102  1.1  christos 	struct proc *p;
    103  1.2   thorpej 	void *v;
    104  1.2   thorpej 	register_t *retval;
    105  1.2   thorpej {
    106  1.3   mycroft 	register struct compat_43_sys_stat_args /* {
    107  1.1  christos 		syscallarg(char *) path;
    108  1.1  christos 		syscallarg(struct ostat *) ub;
    109  1.2   thorpej 	} */ *uap = v;
    110  1.1  christos 	struct stat sb;
    111  1.1  christos 	struct ostat osb;
    112  1.1  christos 	int error;
    113  1.1  christos 	struct nameidata nd;
    114  1.1  christos 
    115  1.1  christos 	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
    116  1.1  christos 	    SCARG(uap, path), p);
    117  1.4  christos 	if ((error = namei(&nd)) != 0)
    118  1.1  christos 		return (error);
    119  1.1  christos 	error = vn_stat(nd.ni_vp, &sb, p);
    120  1.1  christos 	vput(nd.ni_vp);
    121  1.1  christos 	if (error)
    122  1.1  christos 		return (error);
    123  1.1  christos 	cvtstat(&sb, &osb);
    124  1.1  christos 	error = copyout((caddr_t)&osb, (caddr_t)SCARG(uap, ub), sizeof (osb));
    125  1.1  christos 	return (error);
    126  1.1  christos }
    127  1.1  christos 
    128  1.1  christos 
    129  1.1  christos /*
    130  1.1  christos  * Get file status; this version does not follow links.
    131  1.1  christos  */
    132  1.1  christos /* ARGSUSED */
    133  1.1  christos int
    134  1.3   mycroft compat_43_sys_lstat(p, v, retval)
    135  1.1  christos 	struct proc *p;
    136  1.2   thorpej 	void *v;
    137  1.2   thorpej 	register_t *retval;
    138  1.2   thorpej {
    139  1.3   mycroft 	register struct compat_43_sys_lstat_args /* {
    140  1.1  christos 		syscallarg(char *) path;
    141  1.1  christos 		syscallarg(struct ostat *) ub;
    142  1.2   thorpej 	} */ *uap = v;
    143  1.5  christos 	struct stat sb;
    144  1.1  christos 	struct ostat osb;
    145  1.1  christos 	int error;
    146  1.1  christos 	struct nameidata nd;
    147  1.1  christos 
    148  1.5  christos 	NDINIT(&nd, LOOKUP, NOFOLLOW | LOCKLEAF, UIO_USERSPACE,
    149  1.1  christos 	    SCARG(uap, path), p);
    150  1.4  christos 	if ((error = namei(&nd)) != 0)
    151  1.1  christos 		return (error);
    152  1.5  christos 	error = vn_stat(nd.ni_vp, &sb, p);
    153  1.5  christos 	vput(nd.ni_vp);
    154  1.5  christos 	if (error)
    155  1.5  christos 		return (error);
    156  1.1  christos 	cvtstat(&sb, &osb);
    157  1.5  christos 	error = copyout(&osb, SCARG(uap, ub), sizeof (osb));
    158  1.1  christos 	return (error);
    159  1.1  christos }
    160  1.1  christos 
    161  1.1  christos 
    162  1.1  christos /*
    163  1.1  christos  * Return status information about a file descriptor.
    164  1.1  christos  */
    165  1.1  christos /* ARGSUSED */
    166  1.4  christos int
    167  1.3   mycroft compat_43_sys_fstat(p, v, retval)
    168  1.1  christos 	struct proc *p;
    169  1.2   thorpej 	void *v;
    170  1.2   thorpej 	register_t *retval;
    171  1.2   thorpej {
    172  1.3   mycroft 	register struct compat_43_sys_fstat_args /* {
    173  1.1  christos 		syscallarg(int) fd;
    174  1.1  christos 		syscallarg(struct ostat *) sb;
    175  1.2   thorpej 	} */ *uap = v;
    176  1.1  christos 	int fd = SCARG(uap, fd);
    177  1.1  christos 	register struct filedesc *fdp = p->p_fd;
    178  1.1  christos 	register struct file *fp;
    179  1.1  christos 	struct stat ub;
    180  1.1  christos 	struct ostat oub;
    181  1.1  christos 	int error;
    182  1.1  christos 
    183  1.1  christos 	if ((u_int)fd >= fdp->fd_nfiles ||
    184  1.1  christos 	    (fp = fdp->fd_ofiles[fd]) == NULL)
    185  1.1  christos 		return (EBADF);
    186  1.1  christos 	switch (fp->f_type) {
    187  1.1  christos 
    188  1.1  christos 	case DTYPE_VNODE:
    189  1.1  christos 		error = vn_stat((struct vnode *)fp->f_data, &ub, p);
    190  1.1  christos 		break;
    191  1.1  christos 
    192  1.1  christos 	case DTYPE_SOCKET:
    193  1.1  christos 		error = soo_stat((struct socket *)fp->f_data, &ub);
    194  1.1  christos 		break;
    195  1.1  christos 
    196  1.1  christos 	default:
    197  1.1  christos 		panic("ofstat");
    198  1.1  christos 		/*NOTREACHED*/
    199  1.1  christos 	}
    200  1.1  christos 	cvtstat(&ub, &oub);
    201  1.1  christos 	if (error == 0)
    202  1.1  christos 		error = copyout((caddr_t)&oub, (caddr_t)SCARG(uap, sb),
    203  1.1  christos 		    sizeof (oub));
    204  1.1  christos 	return (error);
    205  1.1  christos }
    206  1.1  christos 
    207  1.1  christos 
    208  1.1  christos /*
    209  1.1  christos  * Truncate a file given a file descriptor.
    210  1.1  christos  */
    211  1.1  christos /* ARGSUSED */
    212  1.1  christos int
    213  1.3   mycroft compat_43_sys_ftruncate(p, v, retval)
    214  1.1  christos 	struct proc *p;
    215  1.2   thorpej 	void *v;
    216  1.2   thorpej 	register_t *retval;
    217  1.2   thorpej {
    218  1.3   mycroft 	register struct compat_43_sys_ftruncate_args /* {
    219  1.1  christos 		syscallarg(int) fd;
    220  1.1  christos 		syscallarg(long) length;
    221  1.2   thorpej 	} */ *uap = v;
    222  1.3   mycroft 	struct sys_ftruncate_args /* {
    223  1.1  christos 		syscallarg(int) fd;
    224  1.1  christos 		syscallarg(int) pad;
    225  1.1  christos 		syscallarg(off_t) length;
    226  1.1  christos 	} */ nuap;
    227  1.1  christos 
    228  1.1  christos 	SCARG(&nuap, fd) = SCARG(uap, fd);
    229  1.1  christos 	SCARG(&nuap, length) = SCARG(uap, length);
    230  1.3   mycroft 	return (sys_ftruncate(p, &nuap, retval));
    231  1.1  christos }
    232  1.1  christos 
    233  1.1  christos /*
    234  1.1  christos  * Truncate a file given its path name.
    235  1.1  christos  */
    236  1.1  christos /* ARGSUSED */
    237  1.1  christos int
    238  1.3   mycroft compat_43_sys_truncate(p, v, retval)
    239  1.1  christos 	struct proc *p;
    240  1.2   thorpej 	void *v;
    241  1.2   thorpej 	register_t *retval;
    242  1.2   thorpej {
    243  1.3   mycroft 	register struct compat_43_sys_truncate_args /* {
    244  1.1  christos 		syscallarg(char *) path;
    245  1.1  christos 		syscallarg(long) length;
    246  1.2   thorpej 	} */ *uap = v;
    247  1.3   mycroft 	struct sys_truncate_args /* {
    248  1.1  christos 		syscallarg(char *) path;
    249  1.1  christos 		syscallarg(int) pad;
    250  1.1  christos 		syscallarg(off_t) length;
    251  1.1  christos 	} */ nuap;
    252  1.1  christos 
    253  1.1  christos 	SCARG(&nuap, path) = SCARG(uap, path);
    254  1.1  christos 	SCARG(&nuap, length) = SCARG(uap, length);
    255  1.3   mycroft 	return (sys_truncate(p, &nuap, retval));
    256  1.1  christos }
    257  1.1  christos 
    258  1.1  christos 
    259  1.1  christos /*
    260  1.1  christos  * Reposition read/write file offset.
    261  1.1  christos  */
    262  1.1  christos int
    263  1.3   mycroft compat_43_sys_lseek(p, v, retval)
    264  1.1  christos 	struct proc *p;
    265  1.2   thorpej 	void *v;
    266  1.2   thorpej 	register_t *retval;
    267  1.2   thorpej {
    268  1.3   mycroft 	register struct compat_43_sys_lseek_args /* {
    269  1.1  christos 		syscallarg(int) fd;
    270  1.1  christos 		syscallarg(long) offset;
    271  1.1  christos 		syscallarg(int) whence;
    272  1.2   thorpej 	} */ *uap = v;
    273  1.3   mycroft 	struct sys_lseek_args /* {
    274  1.1  christos 		syscallarg(int) fd;
    275  1.1  christos 		syscallarg(int) pad;
    276  1.1  christos 		syscallarg(off_t) offset;
    277  1.1  christos 		syscallarg(int) whence;
    278  1.1  christos 	} */ nuap;
    279  1.1  christos 	off_t qret;
    280  1.1  christos 	int error;
    281  1.1  christos 
    282  1.1  christos 	SCARG(&nuap, fd) = SCARG(uap, fd);
    283  1.1  christos 	SCARG(&nuap, offset) = SCARG(uap, offset);
    284  1.1  christos 	SCARG(&nuap, whence) = SCARG(uap, whence);
    285  1.3   mycroft 	error = sys_lseek(p, &nuap, (register_t *)&qret);
    286  1.1  christos 	*(long *)retval = qret;
    287  1.1  christos 	return (error);
    288  1.1  christos }
    289  1.1  christos 
    290  1.1  christos 
    291  1.1  christos /*
    292  1.1  christos  * Create a file.
    293  1.1  christos  */
    294  1.1  christos int
    295  1.3   mycroft compat_43_sys_creat(p, v, retval)
    296  1.1  christos 	struct proc *p;
    297  1.2   thorpej 	void *v;
    298  1.2   thorpej 	register_t *retval;
    299  1.2   thorpej {
    300  1.3   mycroft 	register struct compat_43_sys_creat_args /* {
    301  1.1  christos 		syscallarg(char *) path;
    302  1.1  christos 		syscallarg(int) mode;
    303  1.2   thorpej 	} */ *uap = v;
    304  1.3   mycroft 	struct sys_open_args /* {
    305  1.1  christos 		syscallarg(char *) path;
    306  1.1  christos 		syscallarg(int) flags;
    307  1.1  christos 		syscallarg(int) mode;
    308  1.1  christos 	} */ nuap;
    309  1.1  christos 
    310  1.1  christos 	SCARG(&nuap, path) = SCARG(uap, path);
    311  1.1  christos 	SCARG(&nuap, mode) = SCARG(uap, mode);
    312  1.1  christos 	SCARG(&nuap, flags) = O_WRONLY | O_CREAT | O_TRUNC;
    313  1.3   mycroft 	return (sys_open(p, &nuap, retval));
    314  1.1  christos }
    315  1.1  christos 
    316  1.1  christos /*ARGSUSED*/
    317  1.1  christos int
    318  1.3   mycroft compat_43_sys_quota(p, v, retval)
    319  1.1  christos 	struct proc *p;
    320  1.3   mycroft 	void *v;
    321  1.1  christos 	register_t *retval;
    322  1.1  christos {
    323  1.1  christos 
    324  1.1  christos 	return (ENOSYS);
    325  1.1  christos }
    326  1.1  christos 
    327  1.1  christos 
    328  1.1  christos /*
    329  1.1  christos  * Read a block of directory entries in a file system independent format.
    330  1.1  christos  */
    331  1.1  christos int
    332  1.3   mycroft compat_43_sys_getdirentries(p, v, retval)
    333  1.1  christos 	struct proc *p;
    334  1.2   thorpej 	void *v;
    335  1.2   thorpej 	register_t *retval;
    336  1.2   thorpej {
    337  1.3   mycroft 	register struct compat_43_sys_getdirentries_args /* {
    338  1.1  christos 		syscallarg(int) fd;
    339  1.1  christos 		syscallarg(char *) buf;
    340  1.1  christos 		syscallarg(u_int) count;
    341  1.1  christos 		syscallarg(long *) basep;
    342  1.2   thorpej 	} */ *uap = v;
    343  1.1  christos 	register struct vnode *vp;
    344  1.1  christos 	struct file *fp;
    345  1.1  christos 	struct uio auio, kuio;
    346  1.1  christos 	struct iovec aiov, kiov;
    347  1.1  christos 	struct dirent *dp, *edp;
    348  1.1  christos 	caddr_t dirbuf;
    349  1.1  christos 	int error, eofflag, readcnt;
    350  1.1  christos 	long loff;
    351  1.1  christos 
    352  1.4  christos 	if ((error = getvnode(p->p_fd, SCARG(uap, fd), &fp)) != 0)
    353  1.1  christos 		return (error);
    354  1.1  christos 	if ((fp->f_flag & FREAD) == 0)
    355  1.1  christos 		return (EBADF);
    356  1.1  christos 	vp = (struct vnode *)fp->f_data;
    357  1.1  christos unionread:
    358  1.1  christos 	if (vp->v_type != VDIR)
    359  1.1  christos 		return (EINVAL);
    360  1.1  christos 	aiov.iov_base = SCARG(uap, buf);
    361  1.1  christos 	aiov.iov_len = SCARG(uap, count);
    362  1.1  christos 	auio.uio_iov = &aiov;
    363  1.1  christos 	auio.uio_iovcnt = 1;
    364  1.1  christos 	auio.uio_rw = UIO_READ;
    365  1.1  christos 	auio.uio_segflg = UIO_USERSPACE;
    366  1.1  christos 	auio.uio_procp = p;
    367  1.1  christos 	auio.uio_resid = SCARG(uap, count);
    368  1.1  christos 	VOP_LOCK(vp);
    369  1.1  christos 	loff = auio.uio_offset = fp->f_offset;
    370  1.1  christos #	if (BYTE_ORDER != LITTLE_ENDIAN)
    371  1.1  christos 		if (vp->v_mount->mnt_maxsymlinklen <= 0) {
    372  1.1  christos 			error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag,
    373  1.7      fvdl 			    (off_t *)0, 0);
    374  1.1  christos 			fp->f_offset = auio.uio_offset;
    375  1.1  christos 		} else
    376  1.1  christos #	endif
    377  1.1  christos 	{
    378  1.1  christos 		kuio = auio;
    379  1.1  christos 		kuio.uio_iov = &kiov;
    380  1.1  christos 		kuio.uio_segflg = UIO_SYSSPACE;
    381  1.1  christos 		kiov.iov_len = SCARG(uap, count);
    382  1.1  christos 		MALLOC(dirbuf, caddr_t, SCARG(uap, count), M_TEMP, M_WAITOK);
    383  1.1  christos 		kiov.iov_base = dirbuf;
    384  1.1  christos 		error = VOP_READDIR(vp, &kuio, fp->f_cred, &eofflag,
    385  1.6      fvdl 			    (off_t *)0, 0);
    386  1.1  christos 		fp->f_offset = kuio.uio_offset;
    387  1.1  christos 		if (error == 0) {
    388  1.1  christos 			readcnt = SCARG(uap, count) - kuio.uio_resid;
    389  1.1  christos 			edp = (struct dirent *)&dirbuf[readcnt];
    390  1.1  christos 			for (dp = (struct dirent *)dirbuf; dp < edp; ) {
    391  1.1  christos #				if (BYTE_ORDER == LITTLE_ENDIAN)
    392  1.1  christos 					/*
    393  1.1  christos 					 * The expected low byte of
    394  1.1  christos 					 * dp->d_namlen is our dp->d_type.
    395  1.1  christos 					 * The high MBZ byte of dp->d_namlen
    396  1.1  christos 					 * is our dp->d_namlen.
    397  1.1  christos 					 */
    398  1.1  christos 					dp->d_type = dp->d_namlen;
    399  1.1  christos 					dp->d_namlen = 0;
    400  1.1  christos #				else
    401  1.1  christos 					/*
    402  1.1  christos 					 * The dp->d_type is the high byte
    403  1.1  christos 					 * of the expected dp->d_namlen,
    404  1.1  christos 					 * so must be zero'ed.
    405  1.1  christos 					 */
    406  1.1  christos 					dp->d_type = 0;
    407  1.1  christos #				endif
    408  1.1  christos 				if (dp->d_reclen > 0) {
    409  1.1  christos 					dp = (struct dirent *)
    410  1.1  christos 					    ((char *)dp + dp->d_reclen);
    411  1.1  christos 				} else {
    412  1.1  christos 					error = EIO;
    413  1.1  christos 					break;
    414  1.1  christos 				}
    415  1.1  christos 			}
    416  1.1  christos 			if (dp >= edp)
    417  1.1  christos 				error = uiomove(dirbuf, readcnt, &auio);
    418  1.1  christos 		}
    419  1.1  christos 		FREE(dirbuf, M_TEMP);
    420  1.1  christos 	}
    421  1.1  christos 	VOP_UNLOCK(vp);
    422  1.1  christos 	if (error)
    423  1.1  christos 		return (error);
    424  1.1  christos 
    425  1.1  christos #ifdef UNION
    426  1.1  christos {
    427  1.4  christos 	extern int (**union_vnodeop_p) __P((void *));
    428  1.1  christos 	extern struct vnode *union_dircache __P((struct vnode *));
    429  1.1  christos 
    430  1.1  christos 	if ((SCARG(uap, count) == auio.uio_resid) &&
    431  1.1  christos 	    (vp->v_op == union_vnodeop_p)) {
    432  1.1  christos 		struct vnode *lvp;
    433  1.1  christos 
    434  1.1  christos 		lvp = union_dircache(vp);
    435  1.1  christos 		if (lvp != NULLVP) {
    436  1.1  christos 			struct vattr va;
    437  1.1  christos 
    438  1.1  christos 			/*
    439  1.1  christos 			 * If the directory is opaque,
    440  1.1  christos 			 * then don't show lower entries
    441  1.1  christos 			 */
    442  1.1  christos 			error = VOP_GETATTR(vp, &va, fp->f_cred, p);
    443  1.1  christos 			if (va.va_flags & OPAQUE) {
    444  1.1  christos 				vput(lvp);
    445  1.1  christos 				lvp = NULL;
    446  1.1  christos 			}
    447  1.1  christos 		}
    448  1.1  christos 
    449  1.1  christos 		if (lvp != NULLVP) {
    450  1.1  christos 			error = VOP_OPEN(lvp, FREAD, fp->f_cred, p);
    451  1.1  christos 			VOP_UNLOCK(lvp);
    452  1.1  christos 
    453  1.1  christos 			if (error) {
    454  1.1  christos 				vrele(lvp);
    455  1.1  christos 				return (error);
    456  1.1  christos 			}
    457  1.1  christos 			fp->f_data = (caddr_t) lvp;
    458  1.1  christos 			fp->f_offset = 0;
    459  1.1  christos 			error = vn_close(vp, FREAD, fp->f_cred, p);
    460  1.1  christos 			if (error)
    461  1.1  christos 				return (error);
    462  1.1  christos 			vp = lvp;
    463  1.1  christos 			goto unionread;
    464  1.1  christos 		}
    465  1.1  christos 	}
    466  1.1  christos }
    467  1.1  christos #endif /* UNION */
    468  1.1  christos 
    469  1.1  christos 	if ((SCARG(uap, count) == auio.uio_resid) &&
    470  1.1  christos 	    (vp->v_flag & VROOT) &&
    471  1.1  christos 	    (vp->v_mount->mnt_flag & MNT_UNION)) {
    472  1.1  christos 		struct vnode *tvp = vp;
    473  1.1  christos 		vp = vp->v_mount->mnt_vnodecovered;
    474  1.1  christos 		VREF(vp);
    475  1.1  christos 		fp->f_data = (caddr_t) vp;
    476  1.1  christos 		fp->f_offset = 0;
    477  1.1  christos 		vrele(tvp);
    478  1.1  christos 		goto unionread;
    479  1.1  christos 	}
    480  1.1  christos 	error = copyout((caddr_t)&loff, (caddr_t)SCARG(uap, basep),
    481  1.1  christos 	    sizeof(long));
    482  1.1  christos 	*retval = SCARG(uap, count) - auio.uio_resid;
    483  1.1  christos 	return (error);
    484  1.1  christos }
    485