xref: /freebsd/share/man/man9/VFS_CHECKEXP.9 (revision 7fdf597e96a02165cfe22ff357b857d5fa15ed8a)
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25.Dd June 17, 2020
26.Dt VFS_CHECKEXP 9
27.Os
28.Sh NAME
29.Nm VFS_CHECKEXP
30.Nd check if a file system is exported to a client
31.Sh SYNOPSIS
32.In sys/param.h
33.In sys/mount.h
34.Ft int
35.Fo VFS_CHECKEXP
36.Fa "struct mount *mp"
37.Fa "struct sockaddr *nam"
38.Fa "uint64_t *exflagsp"
39.Fa "struct ucred **credanonp"
40.Fa "int *numsecflavor"
41.Fa "int *secflavors"
42.Fc
43.Sh DESCRIPTION
44The
45.Fn VFS_CHECKEXP
46macro is used by the NFS server to check if a mount point is exported
47to a client.
48.Pp
49The arguments it expects are:
50.Bl -tag -width numsecflavors
51.It Fa mp
52The mount point to be checked.
53.It Fa nam
54An mbuf containing the network address of the client.
55.It Fa exflagsp
56Return parameter for the export flags for this client.
57.It Fa credanonp
58Return parameter for the anonymous credentials for this client.
59.It Fa numsecflavors
60Return value for the number of security flavors for this client.
61.It Fa secflavors
62Must be an array of size MAXSECFLAVORS, in which the security flavors
63for this client are returned.
64.El
65.Pp
66The
67.Fn VFS_CHECKEXP
68macro should be called on a file system's mount structure to determine if it
69is exported to a client whose address is contained in
70.Fa nam .
71.Pp
72It is called in the NFS server once a vnode for a file handle has been
73acquired, in order to determine what access the client is allowed on
74the file system the vnode resides in.
75For NFSv4, it is also called whenever the lookup operation crosses a
76server file system mount point, to update the access information.
77.Pp
78The operation is file system specific, but is normally handled by
79the default ``vfs_stdcheckexp''.
80.Sh RETURN VALUES
81The export flags, anonymous credentials and security flavors specific to the
82client
83will be returned in
84.Fa *exflagsp ,
85.Fa *credanonp ,
86.Fa *numsecflavors
87and
88.Fa *secflavors .
89.Sh SEE ALSO
90.Xr VFS 9 ,
91.Xr VFS_FHTOVP 9 ,
92.Xr vnode 9 ,
93.Xr VOP_VPTOFH 9
94.Sh AUTHORS
95This manual page was written by
96.An Alfred Perlstein .
97