libexec/getty/gettytab.5

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.Dd September 29, 2022
.Dt GETTYTAB 5
.Os
.Sh NAME
.Nm gettytab
.Nd terminal configuration data base
.Sh SYNOPSIS
.Nm
.Sh DESCRIPTION
The
.Nm
file
is a simplified version of the
.Xr termcap 5
data base
used to describe terminal lines.
The initial terminal login process
.Xr getty 8
accesses the
.Nm
file each time it starts, allowing simpler
reconfiguration of terminal characteristics.
Each entry in the data base
is used to describe one class of terminals.
.Pp
There is a default terminal class,
.Va default ,
that is used to set global defaults for all other classes.
(That is, the
.Va default
entry is read, then the entry for the class required
is used to override particular settings.)
.Sh CAPABILITIES
Refer to
.Xr termcap 5
for a description of the file layout.
The
.Va default
column below lists defaults obtained if there is
no entry in the table obtained, nor one in the special
.Va default
table.
.Bl -column Name Type /usr/bin/login
.It Sy "Name	Type	Default	Description"
.It "ac	str	unused	expect-send chat script for modem answer"
.It "al	str	unused	user to auto-login instead of prompting"
.It "ap	bool	false	terminal uses any parity"
.It "bk	str	0377	alternate end of line character (input break)"
.It "c0	num	unused	tty control flags to write messages"
.It "c1	num	unused	tty control flags to read login name"
.It "c2	num	unused	tty control flags to leave terminal as"
.It "ce	bool	false	use crt erase algorithm"
.It "ck	bool	false	use crt kill algorithm"
.It "cl	str" Ta Dv NULL
.Ta No "screen clear sequence"
.It "co	bool	false	console - add"
.Ql \en
after login prompt
.It "ct	num	10	chat timeout for"
.Va \&ac
and
.Va \&ic
scripts
.It "dc	num	0	chat debug bitmask"
.It "de	num	0	delay secs and flush input before writing first prompt"
.It "df	str	%+	the" Xr strftime 3 "format used for \&%d in the banner message"
.It "ds	str" Ta So Li ^Y
.Sc Ta No "delayed suspend character"
.It "dx	bool	false	set"
.Dv DECCTLQ
.It "ec	bool	false	leave echo"
.Em OFF
.It "ep	bool	false	terminal uses even parity"
.It "er	str" Ta So Li ^?
.Sc Ta No "erase character"
.It "et	str" Ta So Li ^D
.Sc Ta No "end of text"
.Pq Dv EOF
character
.It "ev	str" Ta Dv NULL
.Ta No "initial environment"
.It "fl	str" Ta So Li ^O
.Sc Ta No "output flush character"
.It "hc	bool	false	do"
.Em NOT
hangup line on last close
.It "he	str" Ta Dv NULL
.Ta No "hostname editing regular expression"
.It "hn	str	hostname	hostname"
.It "ht	bool	false	terminal has real tabs"
.It "hw	bool	false	do cts/rts hardware flow control"
.It "i0	num	unused	tty input flags to write messages"
.It "i1	num	unused	tty input flags to read login name"
.It "i2	num	unused	tty input flags to leave terminal as"
.It "ic	str	unused	expect-send chat script for modem initialization"
.It "if	str	unused	display named file before prompt, like /etc/issue"
.It "ig	bool	false	ignore garbage characters in login name"
.It "im	str" Ta Dv NULL
.Ta No "initial (banner) message"
.It "iM	str" Ta Dv NULL
.Ta No "execute named file to generate initial (banner) message"
.It "in	str" Ta So Li ^C
.Sc Ta No "interrupt character"
.It "is	num	unused	input speed"
.It "kl	str" Ta So Li ^U
.Sc Ta No "kill character"
.It "l0	num	unused	tty local flags to write messages"
.It "l1	num	unused	tty local flags to read login name"
.It "l2	num	unused	tty local flags to leave terminal as"
.It "lm	str	login:	login prompt"
.It "ln	str" Ta So Li ^V
.Sc Ta No "``literal next'' character"
.It "lo	str" Ta Pa /usr/bin/login
.Ta No "program to exec when name obtained"
.It "mb	bool	false	do flow control based on carrier"
.It "nc	bool	false	terminal does not supply carrier (set clocal)"
.It "nl	bool	false	terminal has (or might have) a newline character"
.It "np	bool	false	terminal uses no parity (i.e., 8-bit characters)"
.It "nx	str	default	next table (for auto speed selection)"
.It "o0	num	unused	tty output flags to write messages"
.It "o1	num	unused	tty output flags to read login name"
.It "o2	num	unused	tty output flags to leave terminal as"
.It "op	bool	false	terminal uses odd parity"
.It "os	num	unused	output speed"
.It "pc	str" Ta So Li \e0
.Sc Ta No "pad character"
.It "pe	bool	false	use printer (hard copy) erase algorithm"
.It "pf	num	0	delay"
between first prompt and following flush (seconds)
.It "pl	bool	false	start PPP login program unconditionally if"
.Va \&pp
is specified
.It "pp	str	unused	PPP login program"
.It "ps	bool	false	line connected to a"
.Tn MICOM
port selector
.It "qu	str" Ta So Li \&^\e
.Sc Ta No "quit character"
.It "rp	str" Ta So Li ^R
.Sc Ta No "line retype character"
.It "rt	num	unused	ring timeout when using"
.Va \&ac
.It "rw	bool	false	do"
.Em NOT
use raw for input, use cbreak
.It "sp	num	unused	line speed (input and output)"
.It "su	str" Ta So Li ^Z
.Sc Ta No "suspend character"
.It "tc	str	none	table continuation"
.It "to	num	0	timeout (seconds)"
.It "tt	str" Ta Dv NULL
.Ta No "terminal type (for environment)"
.It "ub	bool	false	do unbuffered output (of prompts etc)"
.It "we	str" Ta So Li ^W
.Sc Ta No "word erase character"
.It "xc	bool	false	do"
.Em NOT
echo control chars as
.Ql ^X
.It "xf	str" Ta So Li ^S Sc Ta Dv XOFF
(stop output) character
.It "xn	str" Ta So Li ^Q Sc Ta Dv XON
(start output) character
.It "Lo	str	C	the locale name used for \&%d in the banner message"
.El
.Pp
The following capabilities are no longer supported by
.Xr getty 8 :
.Bl -column Name Type /usr/bin/login
.It "bd	num	0	backspace delay"
.It "cb	bool	false	use crt backspace mode"
.It "cd	num	0	carriage-return delay"
.It "f0	num	unused	tty mode flags to write messages"
.It "f1	num	unused	tty mode flags to read login name"
.It "f2	num	unused	tty mode flags to leave terminal as"
.It "fd	num	0	form-feed (vertical motion) delay"
.It "lc	bool	false	terminal has lower case"
.It "nd	num	0	newline (line-feed) delay"
.It "uc	bool	false	terminal is known upper case only"
.El
.Pp
If no line speed is specified, speed will not be altered
from that which prevails when getty is entered.
Specifying an input or output speed will override
line speed for stated direction only.
.Pp
Terminal modes to be used for the output of the message,
for input of the login name,
and to leave the terminal set as upon completion,
are derived from the boolean flags specified.
If the derivation should prove inadequate,
any (or all) of these three may be overridden
with one of the
.Va \&c0 ,
.Va \&c1 ,
.Va \&c2 ,
.Va \&i0 ,
.Va \&i1 ,
.Va \&i2 ,
.Va \&l0 ,
.Va \&l1 ,
.Va \&l2 ,
.Va \&o0 ,
.Va \&o1 ,
or
.Va \&o2
numeric specifications, which can be used to specify
(usually in octal, with a leading '0')
the exact values of the flags.
These flags correspond to the termios
.Va c_cflag ,
.Va c_iflag ,
.Va c_lflag ,
and
.Va c_oflag
fields, respectively.
Each these sets must be completely specified to be effective.
.Pp
Should
.Xr getty 8
receive a null character
(presumed to indicate a line break)
it will restart using the table indicated by the
.Va \&nx
entry.
If there is none, it will re-use its original table.
.Pp
Delays are specified in milliseconds, the nearest possible
delay available in the tty driver will be used.
Should greater certainty be desired, delays
with values 0, 1, 2, and 3 are interpreted as
choosing that particular delay algorithm from the driver.
.Pp
The
.Va \&cl
screen clear string may be preceded by a (decimal) number
of milliseconds of delay required (a la termcap).
This delay is simulated by repeated use of the pad character
.Va \&pc .
.Pp
The initial message, login message, and initial file;
.Va \&im ,
.Va \&lm
and
.Va \&if
may include any of the following character sequences, which expand to
information about the environment in which
.Xr getty 8
is running.
.Bl -tag -offset indent -width \&%xxxxxxxxxxxxxx
.It \&%d
The current date and time formatted according to the
.Va \&Lo
and
.Va \&df
strings.
.It \&%h
The hostname of the machine, which is normally obtained from the
system using
.Xr gethostname 3 ,
but may also be overridden by the
.Va \&hn
table entry.
In either case it may be edited with the
.Va \&he
POSIX
.Dq extended
regular expression, which is matched against the hostname.
If there are no parenthesized subexpressions in the pattern,
the entire matched string is used as the final hostname;
otherwise, the first matched subexpression is used instead.
If the pattern does not match, the original hostname is not modified.
.It \&%t
The tty name.
.It "\&%m, \&%r, \&%s, \&%v"
The type of machine, release of the operating system, name of the
operating system, and version of the kernel, respectively, as
returned by
.Xr uname 3 .
.It \&%%
A
.Dq %
character.
.El
.Pp
When getty execs the login process, given
in the
.Va \&lo
string (usually
.Dq Pa /usr/bin/login ) ,
it will have set
the environment to include the terminal type, as indicated
by the
.Va \&tt
string (if it exists).
The
.Va \&ev
string, can be used to enter additional data into
the environment.
It is a list of comma separated strings, each of which
will presumably be of the form
.Li name=value .
.Pp
If a non-zero timeout is specified, with
.Va \&to ,
then getty will exit within the indicated
number of seconds, either having
received a login name and passed control
to
.Xr login 1 ,
or having received an alarm signal, and exited.
This may be useful to hangup dial in lines.
.Pp
Output from
.Xr getty 8
is even parity unless
.Va \&op
or
.Va \&np
is specified.
The
.Va \&op
string
may be specified with
.Va \&ap
to allow any parity on input, but generate odd parity output.
Note: this only applies while getty is being run,
terminal driver limitations prevent a more complete
implementation.
The
.Xr getty 8
utility does not check parity of input characters in
.Dv RAW
mode.
.Pp
If a
.Va \&pp
string is specified and a PPP link bring-up sequence is recognized,
getty will invoke the program referenced by the
.Va \&pp
option.
This can be used to handle incoming PPP calls.
If the
.Va \&pl
option is true as well,
.Xr getty 8
will skip the user name prompt and the PPP detection phase, and will
invoke the program specified by
.Va \&pp
instantly.
.Pp
.Nm Getty
provides some basic intelligent modem handling by providing a chat
script feature available via two capabilities:
.Pp
.Bl -tag -offset indent -width \&xxxxxxxx -compact
.It ic
Chat script to initialize modem.
.It ac
Chat script to answer a call.
.El
.Pp
A chat script is a set of expect/send string pairs.
When a chat string starts,
.Nm getty
will wait for the first string, and if it finds it, will send the
second, and so on.
Strings specified are separated by one or more tabs or spaces.
Strings may contain standard ASCII characters and special 'escapes',
which consist of a backslash character followed by one or more
characters which are interpreted as follows:
.Pp
.Bl -tag -offset indent -width \&xxxxxxxx -compact
.It \ea
bell character.
.It \eb
backspace.
.It \en
newline.
.It \ee
escape.
.It \ef
formfeed.
.It \ep
half-second pause.
.It \er
carriage return.
.It \eS , \es
space character.
.It \et
tab.
.It \exNN
hexadecimal byte value.
.It \e0NNN
octal byte value.
.El
.Pp
Note that the
.Ql \ep
sequence is only valid for send strings and causes a half-second
pause between sending the previous and next characters.
Hexadecimal values are, at most, 2 hex digits long, and octal
values are a maximum of 3 octal digits.
.Pp
The
.Va \&ic
chat sequence is used to initialize a modem or similar device.
A typical example of an init chat script for a modem with a
hayes compatible command set might look like this:
.Pp
.Dl :ic="" ATE0Q0V1\er OK\er ATS0=0\er OK\er:
.Pp
This script waits for nothing (which always succeeds), sends
a sequence to ensure that the modem is in the correct mode
(suppress command echo, send responses in verbose mode),
and then disables auto-answer.
It waits for an "OK" response before it terminates.
The init sequence is used to check modem responses to ensure that
the modem is functioning correctly.
If the init script fails to complete,
.Nm getty
considers this to be fatal, and results in an error logged via
.Xr syslogd 8 ,
and exiting.
.Pp
Similarly, an answer chat script is used to manually answer the
phone in response to (usually) a "RING".
When run with an answer script,
.Nm getty
opens the port in non-blocking mode, clears any extraneous input
and waits for data on the port.
As soon as any data is available, the answer chat script is
started and scanned for a string, and responds according to
the answer chat script.
With a hayes compatible modem, this would normally look something
like:
.Pp
.Dl :ac=RING\er ATA\er CONNECT:
.Pp
This causes the modem to answer the call via the "ATA" command,
then scans input for a "CONNECT" string.
If this is received before a
.Va \&ct
timeout, then a normal login sequence commences.
.Pp
The
.Va \&ct
capability specifies a timeout for all send and expect strings.
This timeout is set individually for each expect wait and send
string and must be at least as long as the time it takes for
a connection to be established between a remote and local
modem (usually around 10 seconds).
.Pp
In most situations, you will want to flush any additional
input after the connection has been detected, and the
.Va \&de
capability may be used to do that, as well as delay for a
short time after the connection has been established during
which all of the connection data has been sent by the modem.
.Sh SEE ALSO
.Xr login 1 ,
.Xr gethostname 3 ,
.Xr uname 3 ,
.Xr termcap 5 ,
.Xr getty 8
.Sh HISTORY
The
.Nm
file format appeared in
.Bx 4.2 .
.Sh BUGS
The special characters (erase, kill, etc.) are reset to system defaults
by
.Xr login 1 .
In
.Em all
cases, '#' or '^H' typed in a login name will be treated as
an erase character, and '@' will be treated as a kill character.
.Pp
The delay stuff is a real crock.
Apart form its general lack of flexibility, some
of the delay algorithms are not implemented.
The terminal driver should support sane delay settings.
.Pp
The
.Xr termcap 5
format is horrid, something more rational should
have been chosen.