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.\" $FreeBSD$ 30.\" 31.Dd August 29, 2008 32.Os 33.Dt VOP_ATTRIB 9 34.Sh NAME 35.Nm VOP_GETATTR , 36.Nm VOP_SETATTR 37.Nd get and set attributes on a file or directory 38.Sh SYNOPSIS 39.In sys/param.h 40.In sys/vnode.h 41.Ft int 42.Fn VOP_GETATTR "struct vnode *vp" "struct vattr *vap" "struct ucred *cred" 43.Ft int 44.Fn VOP_SETATTR "struct vnode *vp" "struct vattr *vap" "struct ucred *cred" 45.Sh DESCRIPTION 46These entry points manipulate various attributes of a file or directory, 47including file permissions, owner, group, size, 48access time and modification time. 49.Pp 50The arguments are: 51.Bl -tag -width cred 52.It Fa vp 53The vnode of the file. 54.It Fa vap 55The attributes of the file. 56.It Fa cred 57The user credentials of the calling process. 58.El 59.Pp 60Attributes which are not being modified by 61.Fn VOP_SETATTR 62should be set to the value 63.Dv VNOVAL ; 64.Fn VATTR_NULL 65may be used to clear all the values, and should generally be used to reset 66the contents of 67.Fa *vap 68prior to setting specific values. 69.Sh LOCKS 70.Fn VOP_GETATTR 71expects the vnode to be locked on entry and will leave the vnode locked on 72return. 73The lock type can be either shared or exclusive. 74.Pp 75.Fn VOP_SETATTR 76expects the vnode to be locked on entry and will leave the vnode locked on 77return. 78The lock type must be exclusive. 79.Sh RETURN VALUES 80.Fn VOP_GETATTR 81returns 0 if it was able to retrieve the attribute data via 82.Fa *vap , 83otherwise an appropriate error is returned. 84.Fn VOP_SETATTR 85returns zero if the attributes were changed successfully, otherwise an 86appropriate error is returned. 87.Sh PSEUDOCODE 88.Bd -literal 89int 90vop_getattr(struct vnode *vp, struct vattr *vap, struct ucred *cred) 91{ 92 93 /* 94 * Fill in the contents of *vap with information from 95 * the file system. 96 */ 97 ...; 98 99 return 0; 100} 101 102int 103vop_setattr(struct vnode *vp, struct vattr *vap, struct ucred *cred) 104{ 105 106 /* 107 * Check for unsettable attributes. 108 */ 109 if ((vap->va_type != VNON) || (vap->va_nlink != VNOVAL) || 110 (vap->va_fsid != VNOVAL) || (vap->va_fileid != VNOVAL) || 111 (vap->va_blocksize != VNOVAL) || (vap->va_rdev != VNOVAL) || 112 ((int)vap->va_bytes != VNOVAL) || (vap->va_gen != VNOVAL)) { 113 return (EINVAL); 114 } 115 116 if (vap->va_flags != VNOVAL) { 117 /* 118 * Set the immutable and append flags of the file. 119 */ 120 } 121 122 if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) { 123 /* 124 * Change owner and/or group of the file. 125 */ 126 } 127 128 if (vap->va_size != VNOVAL) { 129 /* 130 * Truncate the file to the specified size. 131 */ 132 } 133 134 if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) { 135 /* 136 * Change access and/or modification time of file. 137 */ 138 } 139 140 if (vap->va_mode != (mode_t)VNOVAL) { 141 /* 142 * Change permissions of file. 143 */ 144 } 145 146 return 0; 147} 148.Ed 149.Sh ERRORS 150.Bl -tag -width Er 151.It Bq Er EPERM 152The file is immutable. 153.It Bq Er EACCES 154The caller does not have permission to modify the file or directory attributes. 155.It Bq Er EROFS 156The file system is read-only. 157.El 158.Sh SEE ALSO 159.Xr VFS 9 , 160.Xr vnode 9 , 161.Xr VOP_ACCESS 9 162.Sh AUTHORS 163This manual page was written by 164.An Doug Rabson . 165