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— EntireX z/VSE CICS® RPC Server —

Administering the EntireX RPC Server

The EntireX z/VSE CICS® RPC Server allows standard RPC clients to communicate with RPC servers on the operating system z/VSE under CICS. It supports the programming language COBOL. This document covers the following topics:

Customizing the RPC Server
Configuring the RPC Server
Locating and Calling the Target Server
User Exit COBUEX02
Multiple RPC Servers in the same CICS

Customizing the RPC Server

The following elements are used for setting up the CICS RPC Server:

ERXMAIN Control Block
ERXMAIN Macro
RPC Online Maintenance Facility

ERXMAIN Control Block

defines a setup of the CICS RPC Server that is persistent over CICS restarts
is defined with parameters of the ERXMAIN Macro; see column 1 in the table under Configuring the RPC Server
contains the following important settings:
- connection information such as broker ID, see BKRN, server address, see CLZN, SRVN and SVCN
- location and usage of server mapping files, see SVM
- scalability parameters such as endworker, minworker and maxworker, see ENDW, MINW and MAXW
- etc.

ERXMAIN Macro

creates an ERXMAIN Control Block, a persistent setup of the CICS RPC Server
needs to be assembled to define a setup
is defined in Assembler program EMAINGEN (in sublibrary EXP960) - use this for assembling; see Build the ERXMAIN Control Block under Installing EntireX RPC Servers under CICS

RPC Online Maintenance Facility

provides commands (see column 2 in the table below) to vary most of the permanently defined parameters in the ERXMAIN Control Block currently in use. All modifications are lost if CICS is restarted. Use ERXMAIN Macro for permanent modifications
allows you to try out new setups of the CICS RPC Server easily without the need to reassemble the ERXMAIN Control Block.
supports
- starting
- stopping
- pinging
- monitoring
- activating trace
of the CICS RPC Server. See RPC Online Maintenance Facility.

Configuring the RPC Server

The following rules apply for the ERXMAIN Macro syntax (column 1 in table below):

keywords are given in uppercase
there are no abbreviations for keywords

The following rules apply for the RPC Online Maintenance Facility commands (column 2 in table below):

Underscored letters in a command indicate the minimum number of letters that can be used for abbreviation.

For example, in brokerid=localhost, brok is the minimum number of letters that can be used as an abbreviation, i.e. the commands brokerid=localhost and brok=localhost are equivalents.

ERXMAIN Macro Syntax RPC Online Maintenance Facility Commands Default Values Req/
Opt

BKRN

brokerid

ETB001

Broker ID used by the server. See Using the Broker ID in Applications.

Example:
BKRN=myhost.com:1971

CLZN

class

RPC

Server class part of the server address used by the server. The server address must be defined as a service in the broker attribute file (see Service-specific Attributes under Broker Attributes). Case-sensitive, up to 32 characters. Corresponds to CLASS attribute of the broker attribute file.

Example:
CLZN=MyRPC

SRVN

servername

SRV1

Server name part of the server address used by the server. The server address must be defined as a service in the broker attribute file. See Service-specific Attributes under Broker Attributes. Case-sensitive, up to 32 characters. Corresponds to SERVER of the broker attribute file.

Example:
SRVN=mySrv

SVCN

service

CALLNAT

Service part of the server address used by the server. The server address must be defined as a service in the broker attribute file. See Service-specific Attributes under Broker Attributes. Case-sensitive, up to 32 characters. Corresponds to SERVICE attribute of the broker attribute file.

Example:
SVCN=MYSERVICE

CODE

codepage

no codepage transferred

Depending on the internationalization approach, the codepage (locale string) where incoming data is provided to the COBOL server. Conversely, the COBOL server must provide outgoing data in the given codepage, otherwise unpredictable results occur. See What is the Best Internationalization Approach to use? under Internationalization with EntireX for information on which internationalization approach requires a codepage (locale string).

By default, no codepage is transferred to the broker. For the most popular internationalization approach, ICU Conversion, the correct codepage (locale string) must be provided. This means it must:

follow the rules described under Locale String Mapping
be a codepage supported by the broker
be the codepage used in your environment for file and terminal IO, otherwise unpredictable results may occur.

Example:
CODE=ibm-273

COMP

compresslevel

N

Enforce compression when data is transferred between broker and server. See Data Compression in EntireX Broker.

compresslevel= 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8| 9 | Y | N

`0-9`	0=no compression 9=max. compression
`N`	No compression.
`Y`	Compression level 6.

Example:
COMP=6

CYCL

restartcycles

15

Number of restart attempts if the broker is not available. This can be used to keep the CICS RPC Server running while the broker is down for a short time. A restart cycle will be repeated at an interval which is calculated as follows:

timeout + ETB_TIMEOUT + 60 seconds

where	`timeout`	is the RPC server parameter (see this table), and
	`ETB_TIMEOUT`	is the environment variable (see Environment Variables in EntireX)

When the number of cycles is reached and a connection to the broker is not possible, the RPC server stops.

Example:
CYCL=30

DPLY

deployment

NO

Activates the deployment service, see Deployment Service. Required to use the deployment wizard. See Server Mapping Deployment Wizard in the COBOL Wrapper documentation.

`YES`	Activates the deployment service. The RPC server registers the deployment service in the broker.
`NO`	The deployment service is deactivated. The RPC server does not register the deployment service in the broker.

Example:
DPLY=YES

ENCR

encryptionlevel

0

Enforce encryption when data is transferred between client and server. Requires EntireX Security. See ENCRYPTION-LEVEL under Broker ACI Fields.

`0`	Encryption is enforced.
`1`	Encryption is enforced between server and broker kernel.
`2`	Encryption is enforced between server and broker kernel, and also between client and broker.

Example:
ENCR=2

ENDW

endworker

TIMEOUT

`NEVER`	Defines worker model `FIXED` with a fixed number of worker threads. The number of active workers is defined with `ERXMAIN` macro parameter `MINW`.
`TIMEOUT`	Defines slow-shrinking worker model `SCALE`, where the number of worker threads is adjusted to the current number of client requests. With value `TIMEOUT`, all worker threads not used are stopped in the time specified by the `ERXMAIN` macro parameter `TOUT`, except for the minimum number of active workers specified with `ERXMAIN` macro parameter `MINW`. The upper limit of workers parallel active is restricted with `ERXMAIN` macro parameter `MAXW`.
`IMMEDIATE`	Defines fast-shrinking worker model `SCALE`, where the number of worker threads is adjusted to the current number of client requests. With value `IMMEDIATE`, worker threads not used are stopped immediately as soon as they have finished their conversation, except for the minumum number of active workers defined with `ERXMAIN` macro parameter `MINW`. The upper limit of workers active in parallel is restricted with `ERXMAIN` macro parameter `MAXW`.

This parameter is forced to value TIMEOUT if impersonation is switched on, see Impersonation and ERXMAIN macro parameter IMPS.

Example:
ENDW=IMMEDIATE,MINW=2,MAXW=6

MINW

minworker

1

Minimum number of workers active in parallel with worker model SCALE or number of workers in worker model FIXED. See also ERXMAIN macro parameter ENDW.

Example:
MINW=2

MAXW

maxworker

10

Upper limit of workers active in parallel with worker model SCALE. See also ERXMAIN macro parameter ENDW.

Example:
MAXW=2

ETBL

etblnk

BKIMC

Define the broker stub to be used. See Administration of Broker Stubs under z/VSE for available stubs.

Example:
ETBL=BKIMC

EXIT n.a. At startup, the CICS RPC Server will call the user exit to synchronize its version. If successful, the CICS RPC Server will continue and call the user exit for the implemented events. See User Exit COBUEX02. O

IMPS

impersonation

NO

Defines if RPC requests are executed under the user ID of the RPC client. Depending on settings, different levels of checks are done prior to RPC server execution. See also Impersonation. `impersonation= NO \| YES \| AUTO [, sameuser \| , anyuser ]`
`NO`	The RPC request is executed anonymously, which means the user ID of the RPC client is not used. RPC requests are executed under the user ID of the RPC server.
`YES`	The RPC request runs impersonated under the supplied RPC client user ID. For execution of the RPC request, the CICS RPC Server starts a separate impersonated user task, that is, the client must be know to CICS and the supplied password is validated against CICS. The worker model `SCALE` is forced; for details see Impersonation.
`AUTO`	Same as option `YES` above, except that no password validation is performed, that is, the client is treated as already authenticated. For this setting, make sure the RPC client is correctly authenticated; use either a secure broker (validation must be against the correct mainframe security repository where the user IDs are defined) and option `sameuser` or your own security implementation (option `anyuser` is supported for compatibility reasons if you need different broker and server user IDs - the customer-written security implementation must validate the RPC client using the RPC client user ID)
	`sameuser`	The CICS RPC Server checks whether the broker client user ID matches the RPC client user ID. This is the default if `AUTO` is used.
	`anyuser`	The RPC client user ID is used for impersonation. The broker client user ID is ignored.
Notes: EntireX supports two user ID/password pairs: a broker client user ID/password pair and an (optional) RPC user ID/password pair sent from RPC clients to the RPC server. With EntireX Security, the broker client user ID/password pair is checked. The RPC user ID/password pair is designed to be checked by the target RPC server. Thus it is possible to use different user IDs in the broker and target RPC server. RPC clients send the (optional) RPC user ID/password pair in the same way as specifying the Natural user ID/password pair for a Natural RPC Server. See for example Using Natural Security for applications under C \| COBOL \| PL/I \| Web Services \| SOAP/XML \| Java. If the RPC client does not specify the optional RPC user ID/password pair, the broker client user ID is inherited to the RPC user ID and thus used for impersonation by the CICS RPC Server. Example: `IMPS=auto`

LOGN

logon

YES

Execute broker functions LOGON/LOGOFF in worker threads. Must match the setting of the broker attribute AUTOLOGON. Reliable RPC requires logon set to YES. See Reliable RPC.

`NO`	No logon/logoff functions are executed.
`YES`	Logon/logoff functions are executed.

Example:
LOGN=no

n.a. mapname Alias for command memory. O

n.a. memory Command to load an ERXMAIN Control Block. See Modifying Parameters of the RPC Server. O

OPTS

runoption

0

This parameter is for special purposes. It provides the CICS RPC Server with additional information. The runoptions are normally set to meet the platform's requirements. Set this parameter only if a support representive provides you with an option and asks you to do so.

Syntax:
OPTS=(<option-list>) <option-list> = [<option-list>,] <option>

Example:
OPTS=(RUNOPT1,RUNOPT2)

PSWD

password

Password for broker logon. Case-sensitive, up to 32 characters. For more information see broker ACI control block field PASSWORD.

Example:
PSWD=MyPwd

PRELOAD

preload

YES

Enable to call CICS RPC Server with AMODE=24

`YES`	Enable to call RPC server with `AMODE 24` or `31`. Internally the CICS RPC Server preloads the called RPC server before execution to check the `AMODE` and releases the RPC server after this. The disadvantage of this approach is the CICS `USECOUNT` of the called RPC server program is increased by 2 for every executed RPC call.
`NO`	The CICS RPC Server does not preload the called RPC server to check its `AMODE`. All RPC servers are called as running in `AMODE 31`. This option is useful for customers who require the CICS `USECOUNT` in their accounting (increased by 1 for every executed RPC call) but prevents usage of calling RPC Server with `AMODE 24`.

REPL replicatename ESRV CICS transaction ID (uppercase, up to 4 characters) assigned to worker tasks and as default for user tasks if Impersonation is set. In the START-USER event of the user exit (see User Exit COBUEX02) the CICS transaction ID for user tasks can be overridden. See also Introduction to the CICS RPC Server. O

SMH

smhport

0

The port where the server listens for commands from the System Management Hub (SMH). If this port is 0 (default), no port is used and management by the SMH is disabled.

See SMH Listener Service for more information.

Example:
SMH=3001

SVM

svmfile

Usage and location of SVM files. If no SVM parameter is given, the RPC server tries to open the SVM container using CICS file with name ERXSVM. If this CICS file is not available, no server mappings are used. For more information see Usage of SVM Files.

Syntax:
SVM=NO | cicsname

`cicsname`	The RPC server tries to open the SVM container using the CICS file with name `cicsname`.
`no`	No server mappings are used.

Example:
SVM=MYSVM

The server mapping file VSAM (container) must be installed and configured. See Step 1: Define an RPC Server Mapping File - VSAMDEF.J (Optional) under Installing the z/VSE EntireX RPC Servers.

TOUT

timeout

600

Timeout in seconds, used by the server to wait for broker requests. See broker ACI control block field WAIT for more information. Also influences restartcycles.

See worker model SCALE to define the lifetime of worker threads in slow-shrinking worker model SCALE.

Example:
TOUT=300

TRC1 tracedestination CSSL Name of the destination for trace output. A valid CICS transient data queue. O

TRLV

tracelevel

0

Trace level for the server. See also Activating Tracing for the RPC Server.

Syntax:
TRLV= None | Standard | Advanced | Support

`None`	No trace output.
`Standard`	For minimal trace output.
`Advanced`	For detailed trace output.
`Support`	This trace level is for support diagnostics and should only be switched on when requested by Software AG support.

Example:
TRLV=standard

USER

userid

ERXSRV1

Used to identify the server to the broker. See broker ACI control block field USER-ID. Case-sensitive, up to 32 characters.

Example:
USER=MyUid

Locating and Calling the Target Server

The IDL library and IDL program names that come from RPC client are used to locate the RPC server. See library-definition and program-definition. This two-level concept (library and program) has to be mapped to the CICS RPC Server environment.

The approach used to derive the CICS program name for the RPC server depends on whether so-called server mapping files are used or not. See Usage of SVM Files for an introduction.

If SVM files are used, the IDL library and IDL program names are used to form a key to locate the SVM entry in the SVM container. If an SVM entry is found, the CICS program name of the RPC server is derived from the SVM entry. In this case the IDL program name can be different to the CICS program name if it is renamed during wrapping process (see Customize Automatically Generated Server Names) or during the extraction process in the COBOL Mapping Editor (see The Software AG IDL Tree Pane).
If no SVM files are used at all, the IDL program name is used as the CICS program name of the RPC server (the IDL library name is ignored).

To use the CICS RPC Server with COBOL

Make sure that all CICS programs called as RPC servers
- use an interface type supported by the CICS RPC Server for target language COBOL; see Supported Interface Types.
- can be called with an EXEC CICS LINK PROGRAM
- are accessible through the CICS RPL chain
Configure the ERXMAIN macro parameter SVM depending on whether SVM files are used or not.

User Exit COBUEX02

The CICS RPC Server provides a user exit COBUEX02 to influence/control the RPC logic. This section covers the following topics:

User Exit Events
Writing the User Exit
Configuring the User Exit

User Exit Events

The user exit is called on the following events:

graphics/intro_userExits-civs.png

	`START-WORKER` event before a CICS worker task is started. This allows you to programatically set the CICS transaction ID. You can terminate an RPC request by specifying an `ERROR-CODE` and optional `ERROR-TEXT`.
	`START-USER` event. Before an impersonated CICS transaction (worker task) is started, the user exit may change the user ID and CICS transaction ID of the new impersonated worker. See Impersonation. You can terminate an RPC request by specifying an `ERROR-CODE` and optional `ERROR-TEXT`.
	`CALL-START` event. The RPC request (payload data from the RPC client to the RPC server) may be inspected and modified. You can terminate an RPC request by specifying `ERROR-CODE` and optional `ERROR-TEXT`.
	`CALL-END` event. The RPC reply (payload data from the RPC server to the RPC client) may be inspected and modified. If an `ERROR-CODE` and optional `ERROR-TEXT` is given in the API, this error is returned to the RPC client instead of the payload.

Writing the User Exit

The sublibrary EXP960 of the EntireX CICS installation provides the user exit skeleton COBUEX02.C for COBOL. Copy this skeleton so you have your own user exit source for modifications.

Accordingly, a COBOL copybook COBUEX02.CPY is provided in EXP960.

Hint: The copybook extension CPY might not be understood by the z/VSE COBOL compiler. In this case, copy COBUEX02.CPY into your copybook library and rename it to COBUEX02.C. Add this library to your COBOL compiler LIBDEF chain.

The most important API parameters of the user exit are described below. Other parameters are informational and are described in the source code. The user exit program must comply with the EXEC CICS LINK PROGRAM COMMAREA conventions.

Parameter	Description
`VERSION`	Required for future changes. Do not change the skeleton code.
`ERROR-CODE`	You can terminate the current request: Any number between 1 and 9999 will cause the CICS RPC Server to stop execution of the current RPC request and pass back the given error code with message class 1022 to the RPC client. See Message Class 1022 - CICS RPC Server User Exit Messages. With error code 0000, the CICS RPC Server continues as normal.
`ERROR-TEXT`	If the error code is not zero, an error text of up to 256 characters may be applied. This is passed to the RPC client.
`CICS-TRANSID`	Can be applied in the event `START-USER`, otherwise it is informational. Apply the `TRANSID` that your business logic requires.
`CICS-TERMID`	Can be applied in the event `START-USER`, otherwise it is informational. In some (rare) cases, RPC server routines require a terminal ID. Apply the `TERMID` that your business logic requires.
`USERID`	Can be applied in the event `START-USER` otherwise it is informational. Under some circumstances, it might be necessary to change the original `RPC-USERID` from the calling RPC client.
`DATA-POINTER`	This pointer refers to the payload data for the events `CALL-START` and `CALL-END`. The payload to which this pointer is pointing may be inspected as well as modified. The pointer itself must not be changed.

Configuring the User Exit

Apply the name of your exit routine to the EntireX RPC server ERXMAIN macro parameter EXIT. See Configuring the RPC Server.

At startup, the CICS RPC Server will call the named user exit to synchronize its version. If successful, the RPC Online Maintenance Facility will display the user exit as map field "parameter opts". See To display the Server parameters (PF06) under RPC Online Maintenance Facility. The CICS RPC Server will continue and call the user exit for the implemented events.

Multiple RPC Servers in the same CICS

If you need to install multiple instances in the same CICS region, see Installing Multiple EntireX RPC Servers in the same CICS (Optional) under Installing EntireX RPC Servers under CICS in the z/VSE installation documentation.

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