.\" $Id: autologin.man,v 2.8 2012/07/06 20:58:39 ksb Exp $
.\" $Compile: Display%h
.\" $Display: groff -Tascii -man %f | ${PAGER:-less}
.\" $Install: %b -mDeinstall %o %f && cp %f $DESTDIR/usr/local/man/man8/autologin.8
.\" $Deinstall: ${rm-rm} -f $DESTDIR/usr/local/man/[cm]a[nt][18]/autologin.8*
.TH AUTOLOGIN 8 LOCAL
.SH NAME
autologin - create an automatic login session from /etc/inittab
.SH SYNOPSIS
.ds PN "autologin
\fI\*(PN\fP [\fB\-Cu\fP] [\fB\-c\fP\~\fIcommand\fP] [\fB\-e\fP\~\fIenv\fP\fB=\fP\fIval\fP] [\fB\-g\fP\~\fIgroup\fP] [\fB\-l\fP\~\fIlogin\fP] [\fB\-t\fP\~\fItty\fP]
.br
\fI\*(PN\fP \fB\-h\fP
.br
\fI\*(PN\fP \fB\-V\fP
.SH DESCRIPTION
\fIAutologin\fP creates a login session for \fIlogin\fP
by running an \*(lq\fBsu\fP \- \fIloginf\P\*(rq
on the specified device
.RI ( tty ).
If a \fIcommand\fP is given, that command is executed via
.RS
\*(lqsu \fIlogin\fP \-c \fIcommand\fP\*(rq
.RE
.PP
.I Autologin
also changes the ownership of the tty port to the user and sets the
mode to 0600.
.PP
On AIX,
.I autologin
uses \fBgetuserattr\fP(3) to determine which groups are required to
\fBsu\fP to \fIlogin\fP
and sets those groups for the process before executing the
\fBsu\fP(1) command.
.PP
On FreeBSD the gettytab(5) manual page has a new attribue \fBal\fP
which largely replaces \fI\*(PN\fP for a shell.

.SH OPTIONS
.TP
.BI \-C
Asserts the ioctl(2) to redirect console output to the
.I tty
device.
This can be used from \fBconserver\fP's
virtual console facillity to emulate a system console.
.TP
.BI \-c command
Execute command
rather than a login shell.
.TP
.BI \-e env = val
Add the evironment variable assignment
.IB env = val
to the environment.
.TP
.BI \-g group
Add
.I group
to current process group set before running \fBsu\fP(1).
This option probably isn't necessary since the group set should be
properly handled through the use of
\fBgetuserattr\fP(3).
.TP
.BI \-l login
Create the login process for the user \fIlogin\fP.
If none is given the effective uid is used.
.TP
.BI \-t tty
.I tty
is the name of the character-special file that corresponds to the terminal
to be logged in.
If none is given the current controlling terminal is used.
.TP
.B \-u
Don't create a utmp entry.  Normally, an entry is written to
.I /etc/utmp
to maintain a record of users logged into the system.

.SH EXAMPLES
Adding the following line to
.I /etc/inittab
on an AIX machine establishes a root login on the console terminal
.RI ( /dev/tty0 )
with any error messages directed to \fB/dev/consolef\P:
.RS
.nf
cons2:2:respawn:/usr/local/etc/autologin \-t/dev/tty0 \-lroot > /dev/console 2>&1
.fi
.RE
.PP
Adding the following line to \fB/etc/inittab\fP
on an AIX machine causes ssinfo to be logged in on \fB/dev/tty10\fP
with the \fBTERM\fP environment variable set to \*(lqreg20\*(rq:
.RS
.nf
ss10:2:respawn:/usr/local/etc/autologin \-e TERM=reg20 \-t/dev/tty10 \-lssinfo
.fi
.RE
.PP
Adding the following line to \fI/etc/ttytab\fP on a Sun 4.1.\fIx\fP
machine establishes a root login on the console device:
.br
.na
	console "/usr/local/etc/autologin \-lroot \-t"    xterm   on local secure
.ad
.PP
Note that \fIinit\fP provides the \fItty\fP argument on the end of the command.

.SH BUGS
Doesn't add entries to /usr/adm/wtmp or wtmpx.
Depends on init(8) to add any utmp entries, even when it was not
run directly by init.
.P
Only runs on FREEBSD, LINUX,
SUN3, SUN4, SUN5, EPIX, IBMR2 (AIX), PARAGON, HPUX9, 10, 11 (currently).
.P
Some versions of init do not set the session ID, which will cause
complaints about getpgrp and setpgrp and will not associate /dev/tty
with the terminal.
A workaround is to use the \fB\-t\fP option, by forcing \fI\*(PN\fP to
open the terminal, set a process group leader and a session ID we
work around the lame version of init.

.SH FILES
/bin/su
.br
/etc/inittab
.br
/etc/passwd
.br
/etc/utmp

.SH AUTHORS
Jeff W\. Stewart \- Purdue University Computing Center
.br
KS Braunsdorf \- NPC Guild.org

.SH "SEE ALSO"
.hlm 0
su(1), gettytab(5), getuserattr(3),
inittab(5), init(8), conserver(8l)