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vfs_syscalls_43.c revision 1.5.4.1
      1  1.5.4.1   thorpej /*	$NetBSD: vfs_syscalls_43.c,v 1.5.4.1 1997/10/14 10:21:18 thorpej 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  1.5.4.1   thorpej 			    (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  1.5.4.1   thorpej 			    (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