1.\" -*- nroff -*- 2.\" 3.\" Copyright (c) 1996 Doug Rabson 4.\" 5.\" All rights reserved. 6.\" 7.\" This program is free software. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 19.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 22.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28.\" 29.\" $FreeBSD: src/share/man/man9/VOP_READDIR.9,v 1.6.2.1 2001/12/17 11:30:18 ru Exp $ 30.\" 31.Dd July 24, 1996 32.Os 33.Dt VOP_READDIR 9 34.Sh NAME 35.Nm VOP_READDIR 36.Nd read contents of a directory 37.Sh SYNOPSIS 38.In sys/param.h 39.In sys/dirent.h 40.In sys/vnode.h 41.Ft int 42.Fn VOP_READDIR "struct vnode *vp" "struct uio *uio" "struct ucred *cred" "int *eofflag" "int *ncookies" "u_long **cookies" 43.Sh DESCRIPTION 44Read directory entries. 45.Bl -tag -width ncookies 46.It Ar vp 47the vnode of the directory 48.It Ar uio 49where to read the directory contents 50.It Ar cred 51the caller's credentials 52.It Ar eofflag 53return end of file status (NULL if not wanted) 54.It Ar ncookies 55number of directory cookies generated for NFS (NULL if not wanted) 56.It Ar cookies 57directory seek cookies generated for NFS (NULL if not wanted) 58.El 59The directory contents are read into 60.Dv struct dirent 61structures. If the on-disc data structures differ from this then they 62should be translated. 63.Sh LOCKS 64The directory should be locked on entry and will still be locked on exit. 65.Sh RETURN VALUES 66Zero is returned on success, otherwise an error code is returned. 67.Pp 68If this is called from the NFS server, the extra arguments 69.Fa eofflag , 70.Fa ncookies 71and 72.Fa cookies 73are given. 74The value of 75.Fa *eofflag 76should be set to TRUE if the end of the directory is reached while 77reading. 78The directory seek cookies are returned to the NFS client and may be used 79later to restart a directory read part way through the directory. 80There should be one cookie returned per directory entry. The value of 81the cookie should be the offset within the directory where the on-disc 82version of the appropriate directory entry starts. 83Memory for the cookies should be allocated using: 84.Pp 85.Bd -literal 86 ...; 87 *ncookies = number of entries read; 88 *cookies = (u_int*)# 89 malloc(*ncookies * sizeof(u_int), M_TEMP, M_WAITOK); 90.Ed 91.Sh PSEUDOCODE 92.Bd -literal 93int 94vop_readdir(struct vnode *vp, struct uio *uio, struct ucred *cred, 95 int *eofflag, int *ncookies, u_int **cookies) 96{ 97 off_t off; 98 int error = 0; 99 100 /* 101 * Remember the original offset to use later in generating cookies. 102 */ 103 off = uio->uio_offset; 104 105 /* 106 * Read directory contents starting at uio->uio_offset into buffer 107 * pointed to by uio. 108 */ 109 ...; 110 111 if (!error && ncookies != NULL) { 112 struct dirent *dpStart; 113 struct dirent *dpEnd; 114 struct dirent *dp; 115 int count; 116 u_int *cookiebuf; 117 u_int *cookiep; 118 119 if (uio->uio_segflg != UIO_SYSSPACE || uio->uio_iovcnt != 1) 120 panic("vop_readdir: unexpected uio from NFS server"); 121 122 /* 123 * Parse the stuff just read into the uio. 124 */ 125 dpStart = (struct dirent *) 126 (uio->uio_iov->iov_base - (uio->uio_offset - off)); 127 dpEnd = (struct dirent *) uio->uio_iov->iov_base; 128 129 /* 130 * Count number of entries. 131 */ 132 for (dp = dpStart, count = 0; 133 dp < dpEnd; 134 dp = (struct dirent *)((caddr_t) dp + dp->d_reclen)) 135 count++; 136 137 cookiebuf = (u_int *) malloc(count * sizeof(u_int), M_TEMP, M_WAITOK); 138 for (dp = dpStart; cookiep = cookiebuf; 139 dp < dpEnd; 140 dp = (struct dirent *)((caddr_t) dp + dp->d_reclen)) { 141 off += dp->d_reclen; 142 *cookiep++ = (u_int) off; 143 } 144 *ncookies = count; 145 *cookies = cookiebuf; 146 } 147 148 if (eofflag && uio->uio_offset is past the end of the directory) { 149 *eofflag = TRUE; 150 } 151 152 return error; 153} 154.Ed 155.Sh ERRORS 156.Bl -tag -width Er 157.It Bq Er EINVAL 158attempt to read from an illegal offset in the directory 159.It Bq Er EIO 160a read error occurred while reading the directory 161.El 162.Sh SEE ALSO 163.Xr vnode 9 164.Sh AUTHORS 165This man page was written by 166.An Doug Rabson . 167