Add an internal document describing (in a very incomplete way at the moment) how...

[dragonfly.git] / libexec / getty / gettytab.5

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.\"     from: @(#)gettytab.5    8.4 (Berkeley) 4/19/94
.\" $FreeBSD: src/libexec/getty/gettytab.5,v 1.21.2.10 2003/02/06 11:45:31 sobomax Exp $
.\"
.Dd April 19, 1994
.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,
.Em default ,
that is used to set global defaults for all other classes.
(That is, the
.Em 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
.Em default
column below lists defaults obtained if there is
no entry in the table obtained, nor one in the special
.Em 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 ac/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"
.Tn 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 "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 "fl str" Ta So Li ^O Sc Ta
.No "output flush character"
.It "hc bool    false   do"
.Tn NOT
hangup line on last close
.It "he str" Ta Dv NULL Ta
.No "hostname editing string"
.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 "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 "pp str     unused  PPP authentication program"
.It "pl bool    false   don't detect PPP sequence, but start PPP login"
program referenced by pp automatically
.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 ac"
.It "rw bool    false   do"
.Tn 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"
.Tn 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 Ns :
.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 "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
.Em \&c0 ,
.Em \&c1 ,
.Em \&c2 ,
.Em \&i0 ,
.Em \&i1 ,
.Em \&i2 ,
.Em \&l0 ,
.Em \&l1 ,
.Em \&l2 ,
.Em \&o0 ,
.Em \&o1 ,
or
.Em \&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
.Em c_cflag ,
.Em c_iflag ,
.Em c_lflag ,
and
.Em c_oflag
fields, respectively. Each these sets must be completely specified to be
effective.
The
.Em \&f0 ,
.Em \&f1 ,
and
.Em \&f2
are excepted for backwards compatibility with a previous incarnation of
the TTY sub-system. In these flags the bottom 16 bits of the (32 bits)
value contain the sgttyb
.Em sg_flags
field, while the top 16 bits represent the local mode word.
.Pp
Should
.Xr getty 8
receive a null character
(presumed to indicate a line break)
it will restart using the table indicated by the
.Em 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
.Em \&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
.Em \&pc .
.Pp
The initial message, login message, and initial file;
.Em \&im ,
.Em \&lm
and
.Em \&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
.Em \&Lo
and
.Em \&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
.Em \&hn
table entry.
In either case it may be edited with the
.Em \&he
string.
A '@' in the
.Em \&he
string causes one character from the real hostname to
be copied to the final hostname.
A '#' in the
.Em \&he
string causes the next character of the real hostname
to be skipped.
Each character that
is neither '@' nor '#' is copied into the final hostname.
Surplus '@' and '#' characters are ignored.
.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
.Em \&lo
string (usually
.Dq Pa /usr/bin/login ) ,
it will have set
the environment to include the terminal type, as indicated
by the
.Em \&tt
string (if it exists).
The
.Em \&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
.Em name=value .
.Pp
If a non-zero timeout is specified, with
.Em \&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
.Em \&op
or
.Em \&np
is specified.
The
.Em \&op
string
may be specified with
.Em \&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.
.Xr Getty 8
does not check parity of input characters in
.Dv RAW
mode.
.Pp
If
.Em \&pp
string is specified and a PPP link bring up sequence is recognized,
getty will invoke the program referenced by the pp option.  This
can be used to handle incoming PPP calls.
.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
.Em \&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
.Em \&ct timeout, then a normal login sequence commences.
.Pp
The
.Em \&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
.Em \&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 ,
.Xr telnetd 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
.Em \&he
capability is stupid.
.Pp
The
.Xr termcap 5
format is horrid, something more rational should
have been chosen.