.\"	$OpenBSD: fbtab.5,v 1.16 2022/04/21 05:27:53 jmc Exp $
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.\" Copyright (c) 1996 Theo de Raadt
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.Dd $Mdocdate: April 21 2022 $
.Dt FBTAB 5
.Os
.Sh NAME
.Nm fbtab
.Nd change device protection upon login
.Sh DESCRIPTION
The
.Nm
file contains lines which specify how the permissions and ownership of
various system files should be changed based on the user's login device name.
.Pp
Comments start with a
.Ql #
and extend to the end of the line.
Blank lines or lines with only a comment are ignored.
.Pp
All other lines consist of three fields delimited by whitespace.
.Bl -tag -width xxxxxxxxxxxxxxxxxxxx
.It Login Device
The device you have logged in on (e.g.,
.Dq /dev/ttyv0 ) .
.It File Permission
An octal permission number (0600), as used by
.Xr chmod 2 .
.It Other devices
The final field is a colon
.Pq Ql \&:
delimited list of device paths (e.g.,
.Dq /dev/console:/dev/fd0a:/dev/wskbd* ) .
Device paths may include shell-style globbing patterns (see
.Xr glob 7 ) ,
potentially matching multiple devices.
.El
.Pp
The
.Nm
file is used by
.Xr login 1
to
.Xr chown 2
the specified files to the user who has performed a login.
Additionally,
.Xr chmod 2
is used to set the devices to the specified permission.
When a user logs out,
.Xr init 8
is responsible for performing the inverse operation, which results in
the files once again belonging to root.
.Sh FILES
.Bl -tag -width /etc/fbtab -compact
.It Pa /etc/fbtab
.El
.Sh SEE ALSO
.Xr login 1 ,
.Xr login_fbtab 3 ,
.Xr glob 7 ,
.Xr init 8
.Sh AUTHORS
.An Guido van Rooij