BDTUX28—MCS Console Authorization

Type

Authorization (required).

General Description

This exit routine allows an installation to examine the attributes of an MCS console, which are set at the time of system generation. Based on those attributes, the user exit routine can be coded to assign an authorization level for BDT work requests. In later authorization exit routines, this authorization level and the work request associated with the MCS console can be examined and authorized or not authorized.

The exit routine gets control in BDTSS34, the module that handles all MCS console requests.

Table 1 shows the authorization levels required of all BDT commands.

Note:

This exit routine is invoked only for BDT commands having a prefix of “bdt-char” or “BDT”. This exit routine is not invoked if the prefix is “F” (MVS MODIFY command).
Exit routine BDTUX25 checks all commands, no matter how they enter BDT.

Register Conventions at Entry

Because this exit routine is entered using a BALR instruction, the routine must save all registers on entry to the exit routine. Also, because BDTSS34, the routine that calls this exit routine, is reentrant, the user exit routine must also be reentrant.

Register 1

Contains the address of a parameter list:

Word 1

Address of an MCS console origin (SSCMSCID).

Word 2

Address of MCS console authorization information flags (byte 1):

X‘80’–information only
X‘40’–command group I-system
X‘20’–command group II-I/O
X‘10’–command group III-console

The fourth byte (X‘80’) indicates master console. One bit past the master console indicator is the pseudo-master console.

Word 3

Address of an authorization level set by the user exit routine (byte 1).

Register 13

Points to a register save area set up by BDTSS34.

Register 14

Contains the address of the return point in BDTSS34.

Register 15

Contains the entry point address into the BDTUX28 user exit routine.

Register Conventions at Exit

Since the user exit routine is entered directly on a BALR instruction, the routine must restore the BDTSS34 registers on return.

Register 14

Contains the address of the return point in BDTSS34.

Register 15

Used for delivering a return code value from the exit routine:

RC 0: Indicates a normal return. Processing continues.
RC 4: Indicates that an error was encountered. An error message is issued indicating that the command or transaction failed an authorization check and that the transaction failed.

Operation

This exit routine is called by BDTSS34 and executes in the address space of the user. Because BDTSS34 is reentrant code, this exit routine must also be reentrant.

BDTSS34 invokes BDTUX28 for the assignment of authorization levels to all MCS consoles. The user exit routine is passed, as part of the parameter list, the address of the MCS console authorization flags. The routine must determine, based on these flags, what authorization level to assign. This should be set in the CONSAUTH field in the console message area. See Table 1 for the proper authorization levels. The exit routine returns the assigned authorization level in the field pointed to by word 3 of the parameter list. The third word of the parameter list should be passed on entry.

Recovery the Exit Routine Must Establish: You should provide ESTAE protection for the user exit routine in the event of system failure. If you do not include an ESTAE in the routine, an ESTAE that cleans up after the failure of the user exit routine is established by IEFJRASP. IEFJRASP acts as an interface between the communications task (COMTASK) and BDTSS34.

Environment

Point Where Exit Routine Receives Control: The exit routine receives control in BDTSS34.

Address Space: Link pack area.

Task under Which Exit Routine Runs: The exit routine is called by BDTSS34 and runs under the TCB for the user.

PSW State: Supervisor.

Storage Protection Key: Key 0.

Data Areas

Mapping Macros: BDTDREG

Executable Macros: None

What If BDTUX28 Is Not Used?

If no exit routine is provided, BDT will not process commands issued via the command character.