mgettydefs - speed and terminal settings used by mgetty
The
/etc/gettydefs file contains information used by
mgetty(1) to
set up the speed and terminal settings for a line. It also supplies
information on what the
login prompt should look like.
Many versions of UNIX have a version of
getty(1) that also reads
/etc/gettydefs. Both
mgetty and
getty expect similar
formats in
/etc/gettydefs except that, when used by
mgetty,
extended functionality is available. Even so, the additional functions are
simply ignored by standard
getty, so they can co-exist using the same
file. Note, however, that
mgetty can be compiled to use a file
different from
/etc/gettydefs if your
getty gets upset about the
extensions. This manual page documents
/etc/gettydefs and describes the
extended functionality available when used by
mgetty(1). This document
will refer to
getty(1) except where
mgetty's behaviour is
different.
Each entry in
/etc/gettydefs has the following format:
- label# initial-flags # final-flags # login-prompt
#next-label
Each entry is followed by a blank line. The login prompt field can contain
quoted characters which will be converted to other values. The sequences and
their substitutions are:
- \n
- newline
- \r
- carriage return
- \g
- beep
- \b
- backspace
- \v
- vertical tab (VT)
- \f
- formfeed
- \t
- tab
- \L
- portname
- \C
- time in ctime(3) format.
- \N
- number of users currently logged in
- \U
- number of users currently logged in
- \D
- date in DD/MM format
- \T
- time in hh:mm:ss format
- \I
- modem CONNECT attributes
- \sequence
- where "sequence" is a valid strtol format, such
as: \0nnn (octal), \0xnnn (hex), or \nnn (decimal).
Note that standard
getty usually only supports \b, \r and \n.
The various fields are:
- label
- This is the string against which getty tries to
match its second argument. It is often the speed, such as 1200, at
which the terminal is supposed to run, but it need not be (see
below).
- initial-flags
- These flags are the initial ioctl(2) settings to
which the terminal is to be set if a terminal type is not specified to
getty. The flags that getty understands are the ones listed
in termio(7)). mgetty is usually compiled for
termios(7) and often has a more complete set than
getty.
- Normally only the speed flag is required in the
-
initial-flags. getty automatically sets the
terminal to raw input mode and takes care of the other flags. If the
"-s" option is used with mgetty(1) the speed setting is
ignored. The initial-flag settings remain in effect until
getty executes login(1).
- final-flags
- These flags take the same values as the
initial-flags and are set just before getty executes
login. The speed flag is again required, except with mgetty
if the -s flag was supplied. Two other commonly specified
final-flags are TAB3, so that tabs are sent to the terminal
as spaces, and HUPCL, so that the line is hung up on the final
close.
- login-prompt
- This entire field is printed as the login-prompt.
Unlike the above fields where white space (a space, tab or new-line) is
ignored, they are included in the login-prompt field. This field is
ignored if the "-p" option has been specified to
mgetty(1).
- next-label
- specifies the label to use if the user user types a
<break> character, or getty detects a reception error.
Getty searches for the entry with next-label as its
label field and set up the terminal for those settings. Usually, a
series of speeds are linked together in this fashion, into a closed set;
for instance, 2400 linked to 1200, which in turn is linked
to 300, which finally is linked to 2400. next-label
is ignored with mgetty(1).
Several additional composite settings are available for
initial-flags and
final-flags. The following composite flags are supported by
mgetty and are usually supported by
getty:
- SANE
- equivalent to ``stty sane''. (BRKINT, IGNPAR, ISTRIP,
ICRNL, IXON, OPOST, CS8, CREAD, ISIG, ICANON, ECHO, ECHOK)
- ODDP
- Odd parity (CS7, PARENB, PARODD)
-
PARITY,EVENP
- even parity (CS7, PARENB)
-
-ODDP,-PARITY,-EVENP
- no parity (resets PARENB, PARODD, and sets CS8)
- RAW
- raw I/O (no canonical processing) (turns off OPOST,
ICANON)
-
-RAW,COOKED
- enable canonical processing (turns on OPOST, ICANON)
- NL
- Ignore newlines. (ICRNL, ONLCR)
- -NL
- Respect newlines (turns INLCR, IGNCR, ICRNL, ONLCR, OCRNL,
ONLRET off)
- LCASE
- Ignore case - treat all as lowercase. (IUCLC, OLCUC, XCASE)
Is set if mgetty believes login is entirely uppercase.
- -LCASE
- Repect case (turns off IUCLC, OLCUC and XCASE)
- TABS
- output tabs as tabs
-
-TABS,TAB3
- output tabs as spaces
- EK
- Sets VERASE to "#" and VKILL to CKILL
respectively. (note that while many gettys default VERASE to
"#". mgetty defaults VERASE to backspace.)
Additionally,
mgetty (but not
getty) can set any of the control
characters listed in the
c_cc termio(termios) structure by the use of
two tokens:
<character name> <value>
Eg:
VERASE ^h
The value can be set as ``^<character>'', ``\nnn'' or
``\<character>'' (normal UNIX \ escapes).
See the
termio(7) or
termios(7) manual pages to a list of which
``V'' variables can be changed. Note that many of these can be changed in the
c_cc array, but won't have any effect.
If
getty is called without a second argument, the first entry of
/etc/gettydefs is used by
getty, thus making the first entry of
/etc/gettydefs the default entry. It is also used if
getty
cannot find the specified
label.
Mgetty use a default label of
``n'', but this can be changed in the configuration. If
/etc/gettydefs
itself is missing, there is one entry built into the command which brings up a
terminal at
300 (configuration parameter in
mgetty) baud.
It is strongly recommended that after making or modifying
/etc/gettydefs,
it be run through
getty with the check option to be sure there are no
errors.
The following two lines show an example of 300/1200 baud toggle, which is useful
for dial-up ports:
- 1200# B1200 HUPCL # B1200 SANE IXANY TAB3 #login: #300
300# B300 HUPCL # B300 SANE IXANY TAB3 #login: #1200
The following line shows a typical 9600 baud entry for a hard-wired connection
(not currently supported for
mgetty):
- 9600# B9600 # B9600 SANE IXANY IXANY ECHOE TAB3 #login:
#9600
The following line is a typical smart-modem setup, suitable for
mgetty:
-
19200mg#
B19200 #
B19200 SANE VERASE \b VINTR \003 HUPCL #
\n\D \T \N Users @!login: #19200mg
/etc/gettydefs
mgetty(8),
getty(8),
login(1),
ioctl(2),
termio(7),
termios(7).