mgettydefs (4) - Linux Manuals
mgettydefs: speed and terminal settings used by mgetty
mgettydefs - speed and terminal settings used by mgetty
DESCRIPTIONThe /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:
- carriage return
- vertical tab (VT)
- time in ctime(3) format.
- number of users currently logged in
- number of users currently logged in
- date in DD/MM format
- time in hh:mm:ss format
- modem CONNECT attributes
- 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:
- 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).
- 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).
- 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.
- 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).
- 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:
- equivalent to ``stty sane''. (BRKINT, IGNPAR, ISTRIP, ICRNL, IXON, OPOST, CS8, CREAD, ISIG, ICANON, ECHO, ECHOK)
- Odd parity (CS7, PARENB, PARODD)
- even parity (CS7, PARENB)
- no parity (resets PARENB, PARODD, and sets CS8)
- raw I/O (no canonical processing) (turns off OPOST, ICANON)
- enable canonical processing (turns on OPOST, ICANON)
- Ignore newlines. (ICRNL, ONLCR)
- Respect newlines (turns INLCR, IGNCR, ICRNL, ONLCR, OCRNL, ONLRET off)
- Ignore case - treat all as lowercase. (IUCLC, OLCUC, XCASE) Is set if mgetty believes login is entirely uppercase.
- Repect case (turns off IUCLC, OLCUC and XCASE)
- output tabs as tabs
- output tabs as spaces
- 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>
The value can be set as ``^<character>'', ``\nnn'' or ``\<character>'' (normal UNIX \ escapes).
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.
EXAMPLESThe 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