NAME¶

s3270 - IBM host access tool

SYNOPSIS¶

s3270 [options] [host]
s3270 [options] session-file.s3270

DESCRIPTION¶

s3270 opens a telnet connection to an IBM host, then allows a script to control the host login session. It is derived from x3270(1), an X-windows IBM 3270 emulator. It implements RFCs 2355 (TN3270E), 1576 (TN3270) and 1646 (LU name selection), and supports IND$FILE file transfer. The full syntax for host is:

Prepending a P: onto hostname causes the connection to go through the telnet-passthru service rather than directly to the host. See PASSTHRU below.

Prepending an S: onto hostname removes the "extended data stream" option reported to the host. See -tn below for further information.

Prepending an N: onto hostname turns off TN3270E support for the session.

Prepending an L: onto hostname causes s3270 to first create a TLS tunnel to the host, and then create a TN3270 session inside the tunnel. (This function is supported only if s3270 was built with TLS support). Note that TLS-encrypted sessions using the TELNET START-TLS option are negotiated with the host automatically; for these sessions the L: prefix should not be used.

Prepending a Y: onto hostname causes s3270 to skip validation of host TLS certificates. This overrides any other configuration or command-line options.

Prepending an A: onto hostname is equivalent to setting the -nvt option; it forces an NVT-mode session instead of a 3270-mode session.

A specific Logical Unit (LU) name to use may be specified by prepending it to the hostname with an `@'. Multiple LU names to try can be separated by commas. An empty LU can be placed in the list with an extra comma. (Note that the LU name is used for different purposes by different kinds of hosts. For example, CICS uses the LU name as the Terminal ID.)

The hostname may optionally be placed inside square-bracket characters `[' and `]'. This will prevent any colon `:' characters in the hostname from being interpreted as indicating option prefixes or port numbers. This allows numeric IPv6 addresses to be used as hostnames.

On systems that support the forkpty library call, the hostname may be replaced with -e and a command string. This will cause s3270 to connect to a local child process, such as a shell.

The port to connect to defaults to telnet. This can be overridden with the -port option, or by appending a port to the hostname with a colon `:'. (For compatability with previous versions of s3270 and with tn3270(1), the port may also be specified as a second, separate argument.)

An optional accept name (a hostname to accept in the host's TLS certificate) may be specified by appending it to the hostname with an equals sign (`='). The accept name can also be specified with the -accepthostname option.

OPTIONS¶

s3270 understands the following options:

-accepthostname name

Specifies a particular hostname to accept when validating the name presented in the server SSL certificate, instead of comparing to the name used to make the connection.

-cadir directory

Specifies a directory containing CA (root) certificates to use when verifying a certificate provided by the host. (OpenSSL only)

-cafile filename

Specifies a PEM-format file containing CA (root) certificates to use when verifying a certificate provided by the host. (OpenSSL only)

-certfile filename

Specifies a file containing a client certificate to provide to the host. The default file type is PEM.

-clientcert name

Specifies the name of a client certificate to provide to the host. (MacOS only)

-certfiletype type

Specifies the type of the certificate file specified by -certfile. Type can be pem or asn1. (OpenSSL only)

-chainfile filename

Specifies a certificate chain file in PEM format, containing a certificate to provide to the host, as well as one or more intermediate certificates and the CA certificate used to sign that certificate. If -chainfile is specified, it overrides -certfile. (OpenSSL only)

-clear toggle

Sets the initial value of toggle to false.

-codepage name

Specifies an EBCDIC host code page.

-connecttimeout seconds

Specifies the time that s3270 will wait for a host connection to complete.

-devname name

Specifies a device name (workstation ID) for RFC 4777 support.

-httpd [addr:]port

Specifies a port and optional address to listen on for HTTP connections. Addr can be specified as `*' to indicate 0.0.0.0; the default is 127.0.0.1. IPv6 numeric addresses must be specified inside of square brackets, e.g., [::1]:4080 to specify the IPv6 loopback address and TCP port 4080.

Note that this option is mutually-exclusive with the -scriptport option and disables reading actions from standard input.

-keyfile filename

Specifies a file containing the private key for the certificate file (specified via -certfile or -chainfile). The default file type is PEM. (OpenSSL only)

-keyfiletype type

Specifies the type of the private key file specified by -keyfile. Type can be pem or asn1. (OpenSSL only)

-keypasswd type:value

Specifies the password for the private key file (OpenSSL) or client certificate file (MacOS), if it is encrypted. The argument can be file:filename, specifying that the password is in a file, or string:string, specifying the password on the command-line directly. If the private key file is encrypted and no -keypasswd option is given, secure connections will not be allowed.

-km name

Specifies the local encoding method for multi-byte text. name is an encoding name recognized by the ICU library. (Supported only when s3270 is compiled with DBCS support, and necessary only when s3270 cannot figure it out from the locale.)

-loginmacro Action(arg...) ...

Specifies a macro to run at login time.

-minversion version

The minimum required version of s3270, e.g., 4.0ga14. If the running version is less than the specified version, s3270 will abort. The format of a version is major.minortypeiteration. type is ignored, and minor and iteration can be omitted.

-model name

The model of 3270 display to be emulated. The model name is in two parts, either of which may be omitted:

The first part is the base model, which is either 3278 or 3279. 3278 specifies a monochrome (green on black) 3270 display; 3279 specifies a color 3270 display.

The second part is the model number, which specifies the number of rows and columns. Model 4 is the default.

Note: Technically, there is no such 3270 display as a 3279-4 or 3279-5, but most hosts seem to work with them anyway.

The default model is 3279-4.

-noverifycert

For TLS connections, do not verify the host certificate.

-nvt

Start in NVT mode instead of waiting for the host to send data, and make the default terminal type xterm.

-oversize colsxrows

Makes the screen larger than the default for the chosen model number. This option has effect only in combination with extended data stream support (controlled by the "s3270.extended" resource), and only if the host supports the Query Reply structured field. The number of columns multiplied by the number of rows must not exceed 16383 (3fff hex), the limit of 14-bit 3270 buffer addressing.

-port n

Specifies a different TCP port to connect to. n can be a name from /etc/services like telnet, or a number. This option changes the default port number used for all connections. (The positional parameter affects only the initial connection.)

-proxy type:host[:port]

Causes s3270 to connect via the specified proxy, instead of using a direct connection. The host can be an IP address or hostname. The optional port can be a number or a service name. For a list of supported proxy types, see PROXY below.

-scriptport [addr:]port

Specifies a port and optional address to listen on for scripting connections. Addr can be specified as `*' to indicate 0.0.0.0; the default is 127.0.0.1. IPv6 numeric addresses must be specified inside of square brackets, e.g., [::1]:4081 to specify the IPv6 loopback address and TCP port 4081.

Note that this option is mutually-exclusive with the -httpd option and disables reading actions from standard input.

-scriptportonce

Allows s3270 to accept only one script connection. When that connection is broken, s3270 will exit.

-set toggle

Sets the initial value of toggle to true.

-socket

Causes the emulator to create a Unix-domain socket when it starts, for use by script processes to send actions to the emulator. The socket is named /tmp/x3sck.pid. The -p option of x3270if causes it to use this socket, instead of pipes specified by environment variables.

-tn name

Specifies the terminal name to be transmitted over the telnet connection. The default name is IBM-model_name-E, for example, IBM-3278-4-E.

Some hosts are confused by the -E suffix on the terminal name, and will ignore the extra screen area on models 3, 4 and 5. Prepending an S: on the hostname, or setting the "s3270.extended" resource to "false", removes the -E from the terminal name when connecting to such hosts.

The name can also be specified with the "s3270.termName" resource.

-trace

Turns on data stream and event tracing at startup. The default trace file name is /tmp/x3trc.pid.

-tracefile file

Specifies a file to save data stream and event traces into. If the name starts with `>>', data will be appended to the file.

-tracefilesize size

Places a limit on the size of a trace file. If this option is not specified, or is specified as 0 or none, the trace file size will be unlimited. The minimum size is 64 Kbytes. The value of size can have a K or M suffix, indicating kilobytes or megabytes respectively. When the trace file reaches the size limit, it will be renamed with a `-' appended and a new file started.

-user name

Specifies the user name for RFC 4777 support.

-utf8

Forces the local codeset to be UTF-8, ignoring the locale or Windows codepage.

-v

Display the version and build options for s3270 and exit.

-verifycert

For TLS connections, verify the host certificate, and do not allow the connection to complete unless it can be validated. (This is the default setting.) This option is overridden by a Y: prepended to the hostname when connecting.

-xrm "s3270.resource: value"

Sets the value of the named resource to value. Resources control less common s3270 options, and are defined under RESOURCES below.

ACTIONS¶

Here is a complete list of basic s3270 actions. Script-specific actions are described on the x3270-script(1) manual page.

Actions marked with an asterisk (*) may block, sending data to the host and possibly waiting for a response.

Note that certain parameters to s3270 actions (such as the names of files and keymaps) are subject to substitutions:

The character ~ at the beginning of a string is replaced with the user's home directory. A ~ character followed by a username is replaced with that user's home directory.

Environment variables are substituted using the Unix shell convention of $name or ${name}.

Two special pseudo-environment variables are supported. ${TIMESTAMP} is replaced with a microsecond-resolution timestamp; ${UNIQUE} is replaced with a string guaranteed to make a unique filename (the process ID optionally followed by a dash and a string of digits). ${UNIQUE} is used to form trace file names.

FILE TRANSFER¶

The Transfer() action implements IND$FILE file transfer. This action requires that the IND$FILE program be installed on the IBM host, and that the 3270 cursor be located in a field that will accept a TSO or VM/CMS command.

Because of the complexity and number of options for file transfer, the parameters to the Transfer() action can take the unique form of option=value. They can also be given with their parameters separately. Options can appear in any order. Note that if the value contains spaces (such as a VM/CMS file name), then the entire parameter must be quoted, e.g., "hostfile=xxx foo a". With sequential options, this would be hostfile,"xxx foo a". The options are:

The option details are as follows.

direction

send to send a file to the host, receive to receive a file from the host.

hostfile

The name of the file on the host.

localfile

The name of the file on the local workstation.

host

The type of host (which dictates the form of the IND$FILE command): tso (the default), vm or cics.

mode

Use ascii (the default) for a text file, which will be translated between EBCDIC and ASCII as necessary. Use binary for non-text files.

cr

Controls how newline characters are handled when transferring mode=ascii files. remove (the default) strips newline characters in local files before transferring them to the host. add adds newline characters to each host file record before transferring it to the local workstation. keep preserves newline characters when transferring a local file to the host.

remap

Controls text translation for mode=ascii files. The value yes (the default) causes s3270 to remap the text to ensure maximum compatibility between the workstation's character set and encoding and the host's EBCDIC code page. The value no causes s3270 to pass the text to or from the host as-is, leaving all translation to the IND$FILE program on the host.

exist

Controls what happens when the destination file already exists. keep (the default) preserves the file, causing the Transfer() action to fail. replace overwrites the destination file with the source file. append appends the source file to the destination file.

recfm

Controls the record format of files created on the host. (TSO and VM hosts only.) fixed creates a file with fixed-length records. variable creates a file with variable-length records. undefined creates a file with undefined-length records (TSO hosts only). The lrecl option controls the record length or maximum record length for recfm=fixed and recfm=variable files, respectively.

lrecl

Specifies the record length (or maximum record length) for files created on the host. (TSO and VM hosts only.)

blksize

Specifies the block size for files created on the host. (TSO and VM hosts only.)

allocation

Specifies the units for the primaryspace and secondaryspace options: tracks, cylinders or avblock. (TSO hosts only.)

primaryspace

Primary allocation for a file. The units are given by the allocation option. Required when the allocation is specified as something other than default. (TSO hosts only.)

secondaryspace

Secondary allocation for a file. The units are given by the allocation option. (TSO hosts only.)

avblock

Average block size, required when allocation specifies avblock. (TSO hosts only.)

buffersize

Buffer size for DFT-mode transfers. Can range from 256 to 32768. Larger values give better performance, but some hosts may not be able to support them.

There are also resources that control the default values for each of the file transfer parameters. These resources have the same names as the Transfer() keywords, but with ft prepended and the option name capitalized. E.g., the default for the mode keyword is the s3270.ftMode resource.

THE PRINTTEXT ACTION¶

The PrintText() produces screen snapshots in a number of different forms. The default form wth no arguments sends a copy of the screen to the default printer. A single argument is the command to use to print, e.g., lpr.

Multiple arguments can include keywords to control the output of PrintText():

file,filename

Save the output in a file.

html

Save the output as HTML. This option implies file.

rtf

Save the output as RichText. This option implies file. The font defaults to Courier New and the point size defaults to 8. These can be overridden by the printTextFont and printTextSize resources, respectively.

string

Return the output as a string. This can only be used from scripts.

modi

Render modified fields in italics.

caption,text

Add the specified text as a caption above the output. Within text, the special sequence %T% will be replaced with a timestamp.

command,command

Directs the output to a command. This allows one or more of the other keywords to be specified, while still sending the output to the printer.

NESTED SCRIPTS¶

There are several types of nested script functions available.

The String Action

The simplest method for nested scripts is provided via the String() action. The arguments to String() are one or more double-quoted strings which are inserted directly as if typed. The C backslash conventions are honored as follows. (Entries marked * mean that after sending the AID code to the host, s3270 will wait for the host to unlock the keyboard before further processing the string.)

\b	Left()
\exxxx	EBCDIC character in hex
\f	Clear()*
\n	Enter()*
\pan	PA(n)*
\pfnn	PF(nn)*
\r	Newline()
\t	Tab()
\T	BackTab()
\uxxxx	Unicode character in hex
\xxxxx	Unicode character in hex

Note that the numeric values for the \e, \u and \x sequences can be abbreviated to 2 digits. Note also that EBCDIC codes greater than 255 and some Unicode character codes represent DBCS characters, which will work only if s3270 is built with DBCS support and the host allows DBCS input in the current field.

Note: The strings are in ASCII and converted to EBCDIC, so beware of inserting control codes.

There is also an alternate form of the String() action, HexString(), which is used to enter non-printing data. The argument to HexString() is a string of hexadecimal digits, two per character. A leading 0x or 0X is optional. In 3270 mode, the hexadecimal data represent EBCDIC characters, which are entered into the current field. In NVT mode, the hexadecimal data represent ASCII characters, which are sent directly to the host.

The Script Action

This action causes s3270 to start a child process which can execute s3270 actions. Standard input and output from the child process are piped back to s3270. The Script() action is fully documented in x3270-script(1).

PASSTHRU¶

s3270 supports the Sun telnet-passthru service provided by the in.telnet-gw server. This allows outbound telnet connections through a firewall machine. When a P: is prepended to a hostname, s3270 acts much like the itelnet(1) command. It contacts the machine named internet-gateway at the port defined in /etc/services as telnet-passthru (which defaults to 3514). It then passes the requested hostname and port to the in.telnet-gw server.

PROXY¶

The -proxy option or the s3270.proxy resource causes s3270 to use a proxy server to connect to the host. The syntax of the option or resource is:

The special types socks4a and socks5d can also be used to force the proxy server to do the hostname resolution for the SOCKS protocol. Note that only the http and socks5 proxies support a username and password.

RESOURCES¶

Certain s3270 options can be configured via resources. Resources are defined by -xrm options. The definitions are similar to X11 resources, and use a similar syntax. The resources available in s3270 are:

If more than one -xrm option is given for the same resource, the last one on the command line is used.

FILES¶

/usr/local/lib/x3270/ibm_hosts

SEE ALSO¶

x3270-script(1), x3270(1), c3270(1), telnet(1), tn3270(1)
Data Stream Programmer's Reference, IBM GA23-0059
Character Set Reference, IBM GA27-3831
RFC 1576, TN3270 Current Practices
RFC 1646, TN3270 Extensions for LUname and Printer Selection
RFC 2355, TN3270 Enhancements

COPYRIGHTS¶

Copyright 1993-2021, Paul Mattes.
Copyright 2004-2005, Don Russell.
Copyright 2004, Dick Altenbern.
Copyright 1990, Jeff Sparkes.
Copyright 1989, Georgia Tech Research Corporation (GTRC), Atlanta, GA
30332.
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

*

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

*

Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

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Neither the names of Paul Mattes, Don Russell, Dick Altenbern, Jeff Sparkes, GTRC nor the names of their contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY PAUL MATTES, DON RUSSELL, DICK ALTENBERN, JEFF SPARKES AND GTRC "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL PAUL MATTES, DON RUSSELL, DICK ALTENBERN, JEFF SPARKES OR GTRC BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

VERSION¶

s3270 4.0ga14