xref: /freebsd/share/man/man9/VFS_CHECKEXP.9 (revision c1d255d3)
1.\"
2.\" Copyright (c) 1999 Alfred Perlstein
3.\"
4.\" All rights reserved.
5.\"
6.\" This program is free software.
7.\"
8.\" Redistribution and use in source and binary forms, with or without
9.\" modification, are permitted provided that the following condition
10.\" is met:
11.\"    Redistributions of source code must retain the above copyright
12.\"    notice, this condition and the following disclaimer.
13.\"
14.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
15.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
18.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24.\"
25.\" $FreeBSD$
26.\"
27.Dd June 17, 2020
28.Dt VFS_CHECKEXP 9
29.Os
30.Sh NAME
31.Nm VFS_CHECKEXP
32.Nd check if a file system is exported to a client
33.Sh SYNOPSIS
34.In sys/param.h
35.In sys/mount.h
36.Ft int
37.Fo VFS_CHECKEXP
38.Fa "struct mount *mp"
39.Fa "struct sockaddr *nam"
40.Fa "uint64_t *exflagsp"
41.Fa "struct ucred **credanonp"
42.Fa "int *numsecflavor"
43.Fa "int *secflavors"
44.Fc
45.Sh DESCRIPTION
46The
47.Fn VFS_CHECKEXP
48macro is used by the NFS server to check if a mount point is exported
49to a client.
50.Pp
51The arguments it expects are:
52.Bl -tag -width numsecflavors
53.It Fa mp
54The mount point to be checked.
55.It Fa nam
56An mbuf containing the network address of the client.
57.It Fa exflagsp
58Return parameter for the export flags for this client.
59.It Fa credanonp
60Return parameter for the anonymous credentials for this client.
61.It Fa numsecflavors
62Return value for the number of security flavors for this client.
63.It Fa secflavors
64Must be an array of size MAXSECFLAVORS, in which the security flavors
65for this client are returned.
66.El
67.Pp
68The
69.Fn VFS_CHECKEXP
70macro should be called on a file system's mount structure to determine if it
71is exported to a client whose address is contained in
72.Fa nam .
73.Pp
74It is called in the NFS server once a vnode for a file handle has been
75acquired, in order to determine what access the client is allowed on
76the file system the vnode resides in.
77For NFSv4, it is also called whenever the lookup operation crosses a
78server file system mount point, to update the access information.
79.Pp
80The operation is file system specific, but is normally handled by
81the default ``vfs_stdcheckexp''.
82.Sh RETURN VALUES
83The export flags, anonymous credentials and security flavors specific to the
84client
85will be returned in
86.Fa *exflagsp ,
87.Fa *credanonp ,
88.Fa *numsecflavors
89and
90.Fa *secflavors .
91.Sh SEE ALSO
92.Xr VFS 9 ,
93.Xr VFS_FHTOVP 9 ,
94.Xr vnode 9 ,
95.Xr VOP_VPTOFH 9
96.Sh AUTHORS
97This manual page was written by
98.An Alfred Perlstein .
99