175 lines
4.8 KiB
Groff
175 lines
4.8 KiB
Groff
.\" -*- nroff -*-
|
|
.\"
|
|
.\" Copyright (c) 1996 Doug Rabson
|
|
.\"
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This program is free software.
|
|
.\"
|
|
.\" 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 DEVELOPERS ``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 DEVELOPERS 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.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd July 24, 1996
|
|
.Os
|
|
.Dt VOP_READDIR 9
|
|
.Sh NAME
|
|
.Nm VOP_READDIR
|
|
.Nd read contents of a directory
|
|
.Sh SYNOPSIS
|
|
.In sys/param.h
|
|
.In sys/dirent.h
|
|
.In sys/vnode.h
|
|
.Ft int
|
|
.Fn VOP_READDIR "struct vnode *vp" "struct uio *uio" "struct ucred *cred" "int *eofflag" "int *ncookies" "u_long **cookies"
|
|
.Sh DESCRIPTION
|
|
Read directory entries.
|
|
.Bl -tag -width ncookies
|
|
.It Fa vp
|
|
The vnode of the directory.
|
|
.It Fa uio
|
|
Where to read the directory contents.
|
|
.It Fa cred
|
|
The caller's credentials.
|
|
.It Fa eofflag
|
|
Return end of file status
|
|
.Dv ( NULL
|
|
if not wanted).
|
|
.It Fa ncookies
|
|
Number of directory cookies generated for NFS
|
|
.Dv ( NULL
|
|
if not wanted).
|
|
.It Fa cookies
|
|
Directory seek cookies generated for NFS
|
|
.Dv ( NULL
|
|
if not wanted).
|
|
.El
|
|
The directory contents are read into
|
|
.Vt struct dirent
|
|
structures.
|
|
If the on-disc data structures differ from this then they
|
|
should be translated.
|
|
.Sh LOCKS
|
|
The directory should be locked on entry and will still be locked on exit.
|
|
.Sh RETURN VALUES
|
|
Zero is returned on success, otherwise an error code is returned.
|
|
.Pp
|
|
If this is called from the NFS server, the extra arguments
|
|
.Fa eofflag ,
|
|
.Fa ncookies
|
|
and
|
|
.Fa cookies
|
|
are given.
|
|
The value of
|
|
.Fa *eofflag
|
|
should be set to TRUE if the end of the directory is reached while
|
|
reading.
|
|
The directory seek cookies are returned to the NFS client and may be used
|
|
later to restart a directory read part way through the directory.
|
|
There should be one cookie returned per directory entry.
|
|
The value of
|
|
the cookie should be the offset within the directory where the on-disc
|
|
version of the appropriate directory entry starts.
|
|
Memory for the cookies should be allocated using:
|
|
.Pp
|
|
.Bd -literal
|
|
...;
|
|
*ncookies = number of entries read;
|
|
*cookies = (u_int*)#
|
|
malloc(*ncookies * sizeof(u_int), M_TEMP, M_WAITOK);
|
|
.Ed
|
|
.Sh PSEUDOCODE
|
|
.Bd -literal
|
|
int
|
|
vop_readdir(struct vnode *vp, struct uio *uio, struct ucred *cred,
|
|
int *eofflag, int *ncookies, u_int **cookies)
|
|
{
|
|
off_t off;
|
|
int error = 0;
|
|
|
|
/*
|
|
* Remember the original offset to use later in generating cookies.
|
|
*/
|
|
off = uio->uio_offset;
|
|
|
|
/*
|
|
* Read directory contents starting at uio->uio_offset into buffer
|
|
* pointed to by uio.
|
|
*/
|
|
...;
|
|
|
|
if (!error && ncookies != NULL) {
|
|
struct dirent *dpStart;
|
|
struct dirent *dpEnd;
|
|
struct dirent *dp;
|
|
int count;
|
|
u_int *cookiebuf;
|
|
u_int *cookiep;
|
|
|
|
if (uio->uio_segflg != UIO_SYSSPACE || uio->uio_iovcnt != 1)
|
|
panic("vop_readdir: unexpected uio from NFS server");
|
|
|
|
/*
|
|
* Parse the stuff just read into the uio.
|
|
*/
|
|
dpStart = (struct dirent *)
|
|
((char *)uio->uio_iov->iov_base - (uio->uio_offset - off));
|
|
dpEnd = (struct dirent *) uio->uio_iov->iov_base;
|
|
|
|
/*
|
|
* Count number of entries.
|
|
*/
|
|
for (dp = dpStart, count = 0;
|
|
dp < dpEnd;
|
|
dp = (struct dirent *)((caddr_t) dp + dp->d_reclen))
|
|
count++;
|
|
|
|
cookiebuf = (u_int *) malloc(count * sizeof(u_int), M_TEMP, M_WAITOK);
|
|
for (dp = dpStart; cookiep = cookiebuf;
|
|
dp < dpEnd;
|
|
dp = (struct dirent *)((caddr_t) dp + dp->d_reclen)) {
|
|
off += dp->d_reclen;
|
|
*cookiep++ = (u_int) off;
|
|
}
|
|
*ncookies = count;
|
|
*cookies = cookiebuf;
|
|
}
|
|
|
|
if (eofflag && uio->uio_offset is past the end of the directory) {
|
|
*eofflag = TRUE;
|
|
}
|
|
|
|
return error;
|
|
}
|
|
.Ed
|
|
.Sh ERRORS
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
An attempt was made to read from an illegal offset in the directory.
|
|
.It Bq Er EIO
|
|
A read error occurred while reading the directory.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr vnode 9
|
|
.Sh AUTHORS
|
|
This manual page was written by
|
|
.An Doug Rabson .
|