port monitor for terminal ports
/usr/lib/saf/ttymon -g [-h] [-d device] [-l ttylabel] [-t timeout]
[-p prompt] [-m modules]
ttymon is a STREAMS-based
Its function is to monitor ports, to set terminal modes, baud rates, and
line disciplines for the ports,
to identify and authenticate users, if required,
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).
This is commonly referred to as Daemon Mode.
It is configured using the
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
When an instance of ttymon is invoked by the sac command,
it starts to monitor its ports.
If ttymon is disabled, all ports under that instance of
ttymon will also be disabled.
For each port, ttymon first
initializes the line discipline, and the speed and
The values used for initialization are taken from the appropriate
entry in the
This file is maintained by the
An alternative method of invoking ttymon is the
Express Mode that is used to monitor a single port.
ttymon writes the information from the
file, then the login prompt, and waits for user input.
If the user shows that the speed is inappropriate by pressing the
BREAK key, ttymon hunts to the next ttylabel in the
/etc/ttydefs file, adjusts
and writes the prompt again.
When valid input
is received, that is, one or more non-break keys followed by a newline,
ttymon interprets the per-service configuration file
for the port, if one exists,
invokes the identification and authentication scheme, if one is specified,
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
1200, 2400, 4800, 9600,
19200, 38400 and 115200.
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.
The bidirectional port option is supported only in Daemon Mode;
it is not supported in Express Mode.
If the connect-on-carrier flag is set for a port,
ttymon will 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.
The service ttymon invokes for a port is specified in the
ttymon administrative file.
ttymon scans the character string that gives the service to
be invoked, looking for one of
the two-character sequences ``%d'' and ``%%''.
If ``%d'' is found, ttymon modifies the service command to be executed
by replacing these two characters with the full pathname of
the port (the device name).
If ``%%'' is found, ttymon replaces the two characters with
a single ``%''.
When the service is invoked, file descriptors 0, 1,
and 2 are opened to the port
device for reading and writing.
If an authentication scheme is specified in the ttymon administrative file
and there is no entry in the
field (this is the default case),
the service is invoked with the
and current home directory set, through set_id,
to the user name that is identified and authenticated by the authentication
If both a user
and an authentication scheme are specified
in the ttymon administrative file,
the authentication scheme is executed first, then
is set, using the value in the administrative file, not the value
given by the authentication scheme.
The login authentication scheme is the scheme most commonly
associated with ttymon.
ttymon adds two environment variables, HOME and
to the service's environment.
HOME is set to the home
directory of the user name under which the service is
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.
In Express Mode (or standalone)
ttymon takes the following options:
On startup, ttymon will list all open virtual terminals (vts)
associated with the device specified (typically /dev/console).
On exit, the user will be prompted to close all open vts
either manually or automatically.
Choosing manual places the user in the highest numbered vt
at which point the user must manually exit from each vt.
Choosing automatic will cause the signals SIGHUP and
to each open vt, then after 3 seconds SIGTERM will be sent
to each open vt to ensure termination.
A special invocation of ttymon is provided with the
This option is used for the ttymon Express Mode.
This form of the command should only be called by
that need to set the correct baud rate and terminal settings on a port
to invoke the LOGIN authentication scheme and
then connect to a service, but that cannot be
pre-configured under the
The following combinations of options can be used with -g:
device is the full pathname 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
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.
Specifies that ttymon should exit if no one types anything
in timeout seconds after the prompt is sent.
ttylabel is a link to a speed and
definition in the
This definition tells ttymon at what speed to run initially,
what the initial
and what speed to try next if the user shows that the speed is
inappropriate by pressing the
The default speed is 9600 baud.
Allows the user to specify a prompt string.
The default prompt is
modules is a comma-separated list of pushable
When initializing the port, ttymon
will pop all modules on the port and then push modules in the
The line discipline module ldterm is commonly used for terminal
language-specific message file (see LANG on
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.
``Smart modems'' are ones that can communicate at different speeds
between the line and the serial port.
Do not use the autobaud feature for smart modems
for incoming or bidirectional lines.
A good choice for smart modems is the highest baud rate
that the modem can support.
Use the same speed for outgoing cu connections that ttymon
uses to monitor incoming connections or the modem will continue to use
the speed specified by the cu.
Smart modems that send result codes
can result in a premature runtime connection indication.
This behavior can be handled by the appropriate modem commands
or by using the -r option for ttyadm, and enabling the Daemon Mode.
for more information.
It is recommended that you use default settings on your modems.
when you want to have the DTR held high on exit for a longer time,
in the Daemon Mode add the line:
'assign DTR_DELAY=delay '
to the /etc/saf/pmtag/_config file.
In the Express Mode, add:
sh -c 'DTR_DELAY=delay ttymon -g...'
to the /etc/inttab file.
In both cases, delay is in milliseconds.
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004