xref: /dragonfly/share/man/man9/VOP_ATTRIB.9 (revision c89a6c1b) 
1.\" Copyright (c) 1996 Doug Rabson
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27.\" $FreeBSD: src/share/man/man9/VOP_ATTRIB.9,v 1.9.2.2 2001/12/17 11:30:18 ru Exp $
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29.\"
30.Dd July 24, 1996
31.Os
32.Dt VOP_ATTRIB 9
33.Sh NAME
34.Nm VOP_GETATTR ,
35.Nm VOP_SETATTR
36.Nd get and set attributes on a file or directory
37.Sh SYNOPSIS
38.In sys/param.h
39.In sys/vnode.h
40.Ft int
41.Fn VOP_GETATTR "struct vnode *vp" "struct vattr *vap" "struct ucred *cred" "struct proc *p"
42.Ft int
43.Fn VOP_SETATTR "struct vnode *vp" "struct vattr *vap" "struct ucred *cred" "struct proc *p"
44.Sh DESCRIPTION
45These entry points manipulate various attributes of a file or directory,
46including file permissions, owner, group, size,
47access time and modification time.
48.Pp
49The arguments are:
50.Bl -tag -width cred
51.It Ar vp
52the vnode of the file
53.It Ar vap
54the attributes of the file
55.It Ar cred
56the user credentials of the calling process
57.It Ar p
58the process
59.El
60.Pp
61Attributes which are not being modified by
62.Xr VOP_SETATTR 9
63should be set to the value
64.Dv VNOVAL .
65.Sh LOCKS
66.Xr VOP_GETATTR 9
67expects the vnode to be locked on entry and will leave the vnode locked on
68return.
69.Pp
70.Xr VOP_SETATTR 9
71expects the vnode to be locked on entry and will leave the vnode locked on
72return.
73.Sh RETURN VALUES
74.Xr VOP_GETATTR 9
75returns information about the file in
76.Fa *vap .
77.Xr VOP_SETATTR 9
78returns zero if the attributes were changed successfully, otherwise an
79appropriate error is returned.
80.Sh PSEUDOCODE
81.Bd -literal
82int
83vop_getattr(struct vnode *vp, struct vattr *vap,
84	    struct ucred *cred, struct proc *p)
85{
86    /*
87     * Fill in the contents of *vap with information from
88     * the filesystem.
89     */
90    ...;
91
92    return 0;
93}
94
95int
96vop_setattr(struct vnode *vp, struct vattr *vap,
97	    struct ucred *cred, struct proc *p)
98{
99    /*
100     * Check for unsettable attributes.
101     */
102    if ((vap->va_type != VNON) || (vap->va_nlink != VNOVAL) ||
103	(vap->va_fsid != VNOVAL) || (vap->va_fileid != VNOVAL) ||
104	(vap->va_blocksize != VNOVAL) || (vap->va_rdev != VNOVAL) ||
105	((int)vap->va_bytes != VNOVAL) || (vap->va_gen != VNOVAL)) {
106	return (EINVAL);
107    }
108
109    if (vap->va_flags != VNOVAL) {
110	/*
111	 * Set the immutable and append flags of the file.
112	 */
113    }
114
115    if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) {
116	/*
117	 * Change owner and/or group of the file.
118	 */
119    }
120
121    if (vap->va_size != VNOVAL) {
122	/*
123	 * Truncate the file to the specified size.
124	 */
125    }
126
127    if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
128	/*
129	 * Change access and/or modification time of file.
130	 */
131    }
132
133    if (vap->va_mode != (mode_t)VNOVAL) {
134	/*
135	 * Change permissions of file.
136	 */
137    }
138
139    return 0;
140}
141.Ed
142.Sh ERRORS
143.Bl -tag -width Er
144.It Bq Er EPERM
145The file is immutable
146.It Bq Er EACCES
147Permission denied
148.It Bq Er EROFS
149The filesystem is readonly
150.El
151.Sh SEE ALSO
152.Xr vnode 9 ,
153.Xr VOP_ACCESS 9
154.Sh AUTHORS
155This man page was written by
156.An Doug Rabson .
157