ttymon(1M) ttymon(1M)
NAME
ttymon - port monitor for terminal ports
SYNOPSIS
/usr/lib/saf/ttymon
/usr/lib/saf/ttymon -g [ -d device ] [ -h ] [ -t timeout ] [-l
ttylabel ] \
[ -p prompt ] [ -m modules ]
DESCRIPTION
ttymon is a STREAMS-based TTY port monitor. Its function is to
monitor ports, to set terminal modes, baud rates, and line
disciplines for the ports, and to connect users or applications to
services associated with the ports. Normally, ttymon is configured
to run under the Service Access Controller, sac, as part of the
Service Access Facility (SAF). It is configured using the sacadm
command. Each instance of ttymon can monitor multiple ports. The
ports monitored by an instance of ttymon are specified in the port
monitor's administrative file. The administrative file is configured
using the pmadm and ttyadm commands. When an instance of ttymon is
invoked by the sac command, it starts to monitor its ports. For each
port, ttymon first initializes the line disciplines, if they are
specified, and the speed and terminal settings. The values used for
initialization are taken from the appropriate entry in the TTY
settings file. This file is maintained by the sttydefs command.
Default line disciplines on ports are usually set up by the autopush
command of the Autopush Facility.
ttymon then writes the prompt and waits for user input. If the user
indicates that the speed is inappropriate by pressing the BREAK key,
ttymon tries the next speed and writes the prompt again. When valid
input is received, ttymon interprets the per-service configuration
file for the port, if one exists, creates a utmp entry if required,
establishes the service environment, and then invokes the service
associated with the port. Valid input consists of a string of at
least one non-newline character, terminated by a carriage return.
After the service terminates, ttymon cleans up the utmp entry, if one
exists, and returns the port to its initial state.
If autobaud is enabled for a port, ttymon will try to determine the
baud rate on the port automatically. Users must enter a carriage
return before ttymon can recognize the baud rate and print the
prompt. Currently, the baud rates that can be determined by autobaud
are 110, 1200, 2400, 4800, and 9600.
If a port is configured as a bidirectional port, ttymon will allow
users to connect to a service, and, if the port is free, will allow
uucico, cu or ct to use it for dialing out. If a port is
bidirectional, ttymon will wait to read a character before it prints
a prompt.
If the connect-on-carrier flag is set for a port, ttymon will
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immediately invoke the port's associated service when a connection
request is received. The prompt message will not be sent.
If a port is disabled, ttymon will not start any service on that
port. If a disabled message is specified, ttymon will send out the
disabled message when a connection request is received. If ttymon is
disabled, all ports under that instance of ttymon will also be
disabled.
SERVICE INVOCATION
The service ttymon invokes for a port is specified in the ttymon
administrative file. ttymon will scan the character string giving the
service to be invoked for this port, looking for a %d or a %% two-
character sequence. If %d is found, ttymon will modify the service
command to be executed by replacing those two characters by the full
path name of this port (the device name). If %% is found, they will
be replaced by a single %.
When the service is invoked, file descriptor 0, 1, and 2 are opened
to the port device for reading and writing. The service is invoked
with the user ID, group ID and current home directory set to that of
the user name under which the service was registered with ttymon.
Two environment variables, HOME and TTYPROMPT, are added to the
service's environment by ttymon. HOME is set to the HOME directory
of the user name under which the service is invoked. TTYPROMPT is
set to the prompt string configured for the service on the port.
This is provided so that a service invoked by ttymon has a means of
determining if a prompt was actually issued by ttymon and, if so,
what that prompt actually was.
See ttyadm(1M) for options that can be set for ports monitored by
ttymon under the Service Access Controller.
INVOKING A STAND-ALONE ttymon PROCESS
A special invocation of ttymon is provided with the -g option. This
form of the command should only be called by applications that need
to set the correct baud rate and terminal settings on a port and then
connect to login service, but that cannot be pre-configured under the
SAC. The following combinations of options can be used with -g:
-d device device is the full path name of the port to which
ttymon is to attach. If this option is not specified,
file descriptor 0 must be set up by the invoking
process to a TTY port.
-h If the -h flag is not set, ttymon will force a hangup
on the line by setting the speed to zero before
setting the speed to the default or specified speed.
-t timeout Specifies that ttymon should exit if no one types
anything in timeout seconds after the prompt is sent.
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ttymon(1M) ttymon(1M)
-l ttylabel ttylabel is a link to a speed and TTY definition in
the ttydefs file. This definition tells ttymon at
what speed to run initially, what the initial TTY
settings are, and what speed to try next if the user
indicates that the speed is inappropriate by pressing
the BREAK key. The default speed is 9600 baud.
-p prompt Allows the user to specify a prompt string. The
default prompt is "Login: ".
-m modules When initializing the port, ttymon will pop all
modules on the port, and then push modules in the
order specified. modules is a comma-separated list of
pushable modules. Default modules on the ports are
usually set up by the Autopush Facility.
SEE ALSO
pmadm(1M), sac(1M), sacadm(1M), ttyadm(1M).
System Administrator's Guide, ``The Port Monitor ttymon.''
NOTES
If a port is monitored by more than one ttymon, it is possible for
the ttymons to send out prompt messages in such a way that they
compete for input.
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