getty(8)getty(8)Namegetty - set terminal mode
Syntax
/etc/getty [ type ] [ tty ]
Description
The routine is one of several ( ) by which users gain access to the
ULTRIX system from a terminal. The routine initializes a terminal
line, reads a login name, and invokes While reading the name, the rou‐
tine tries to adapt the system to the speed and type of terminal on the
line specified by the argument.
The command typically invokes as directed by the command field in the
file.
The routine first tries to initialize the line. It examines and sets
up the line for local or remote connections, as appropriate. Next, the
routine calls to revoke access to the terminal by any background pro‐
cesses that could have open. The routine then opens for reading and
writing. File descriptors 0, 1, and 2 become the standard input, out‐
put, and diagnostic devices. If the terminal line is connected to a
modem, the open is not completed until someone dials up and establishes
carrier on the channel.
If a terminal exists, but an error occurs when trying to open the ter‐
minal, the routine writes a message to the system console. The message
is repeated every 10 minutes until the terminal is available, or the
entry for the terminal is modified to indicate that the terminal is
off, and is notified by a hangup.
The routine checks every minute to see if the terminal is still off.
Next, the routine reads a login name, terminated by a newline or car‐
riage-return character. For a carriage return, the system is set to
treat carriage returns appropriately. For further information, see
The routine scans the user's name to see if it contains any lowercase
alphabetic characters. If it does not, and the name is nonempty, the
system is told to map any future uppercase characters into the corre‐
sponding lowercase characters.
Finally, calls with the user's name as an argument.
Most of the default actions of can be changed with a suitable table.
The routine can be set to timeout after some interval with the to vari‐
able in the table. Thus, if the user does not enter a login name after
a reasonable amount of time, hangs up the dialup line.
Arguments
tty The special device file in the directory to open for the termi‐
nal (for example, ttyh0). If there is no argument or the argu‐
ment is "+", the terminal line is assumed to be open as file
descriptor 0.
type Used to make treat the line specially. This argument is used as
an index into the database, to determine the characteristics of
the line. If there is no argument, or there is no such table,
the default entry in is used. If there is no a set of system
defaults is used.
The entry is used to define specific terminal hardware
attributes such as the baud rate and number of bits per charac‐
ter. Terminals which are setup to transmit and receive 8-bit
characters must specify a gettytab entry which appropriately
sets up the line. For example a terminal line setup to operate
at 9600 baud with 8-bit characters may use the "8bit.9600" get‐
tytab entry. If a terminal is setup to use 8-bit characters,
but uses a 7-bit gettytab entry (such as "std.9600") the output
from the getty program may be corrupted. This output corruption
appears as multinational characters being generated by or pro‐
grams. When these programs operate in 7-bit mode, the high
order bit of the character is used as software provided parity.
This parity generation causes conventional ASCII characters to
be transformed into multinational characters. By using an 8-bit
gettytab entry, characters will be transmitted without any soft‐
ware generated parity.
If indicated by the table located, will clear the terminal
screen, print a banner heading, and prompt for a login name.
Usually either the banner or the login prompt will include the
system hostname. Then the user's name is read, a character at a
time. If a null character is received, it is assumed to be the
result of the user pushing the break (interrupt) key. The speed
is usually then changed and the ``login:'' prompt is displayed
again. a second break changes the speed again and redisplays
the ``login:'' prompt. Successive break characters cycle
through some standard set of speeds.
Diagnostics
The uses to produce diagnostic messages. Therefore, the syslog config‐
uration file will determine where the messages are printed. For fur‐
ther information, see
getty: tty: cannot open
A terminal which is turned on in the file cannot be opened. This is
probably because the requisite lines are either not configured into the
system or the associated device was not attached during boot-time sys‐
tem configuration. The syslog error logging level is LOG_ERR.
getty: command, tty failing, open blocked
The routine tried a non-blocking open of the terminal line and the open
still blocked. This can only happen on devices that have not imple‐
mented O_NDELAY. For further information, see The routine tries to
continue but the line may not be properly initialized. The syslog
error logging level is LOG_ERR.
getty: command, tty open failed, reason
The routine tried a non-blocking open of the terminal line and the open
failed. The reason is the explanation produced by the routine for why
the open failed. The routine tries to continue but the line may not be
properly initialized. The syslog error logging level is LOG_ERR.
getty: in use line tty
The Itty is in use by some other process. The routine will not ini‐
tialize a line that is already in use. The routine will block until
the line is no longer in use. See and for discussions on shared lines.
The syslog error logging level is LOG_INFO.
getty could not set pgrp, reason
The routine tried and failed to initialize the process group of the
terminal to process group 0. See for a discussion of process groups.
The reason is the explanation produced by for the failure. The syslog
error logging level is LOG_INFO.
Files
Data base describing terminal lines
See Alsologin(1), tty(4), gettytab(5), ttys(5), init(8), syslog(8)getty(8)
