You can use multiple exits with logon procedures to provide different default environments for certain classes of users and to monitor groups of users in the same way.

If you had three Session Manager exits (EX1, EX2, and EX3), you could link-edit them into the ENV1 and ENV2 modules. All Session Manager users would be monitored by the exits regardless of whether they log on with the LOG1 or LOG2 procedure.

To monitor users who use the LOG2 procedure differently, you could write a second stream monitoring exit (NEWEX2). Link-edit NEWEX2 into the ENV2 default environment module or incorporate NEWEX2 directly into the ENV2 module and reassemble ENV2. Then, users who log on with the LOG1 procedure are monitored by the EX1, EX2, and EX3 exits; users who use the LOG2 procedure are monitored by the EX1, NEWEX2, and EX3 exits.

For example, you can monitor TSO/E input and restrict specific users or groups of users from using certain commands. When the exit intercepts the command, it can change it to blanks or some other characters. If you eliminate commands in this way, you must not change the length of the line.

If you monitor an input stream, you should be aware that the command may not be ready to execute because other commands may be stacked ahead of it. At this point, the input line is being placed into the input stream. If you want the exit to perform an action on that specific command, detect the command as it is copied to the output stream. At that point, Session Manager is returning the command to TSO/E in order for it to execute.

If you want the exit to intercept a specific command as it is copied to the output stream, you do not have to monitor every line of output. Monitor only the input until the exit detects the command. The exit can then start monitoring the output until the command is copied to the output stream. The exit can perform the required action and then go back to monitoring input only.

To dynamically change which streams are being monitored, use the initialization and stream monitoring exits. The initialization exit can save the address of the stream mapping in the "installation data" fullword. The stream monitoring exit can change the stream mapping that defines which streams are being monitored. For example, if you are monitoring TSO/E input and detect a particular command, you can start monitoring the TSO/E output stream. When the next command is retrieved for TSO/E input, you can then go back to monitoring only TSO/E input.

To monitor the input, output, and message streams and write each line to a data set, use the stream monitoring exit. To create a hard copy of the data set, use the termination exit.

The stream monitoring exit must not do any I/O operations. To prevent performance degradation, the initialization exit can attach another task during initialization to handle I/O requests from the stream monitoring exit. Whenever the stream monitoring exit is ready to write a record, it can post the I/O task and pass it a buffer with the record. The stream monitoring exit can then return to ADFIMPUT, which lets Session Manager continue while the I/O task is asynchronously writing the record.

The task that the initialization exit attaches runs without holding the local lock; therefore, the stream monitoring exit must not release the local lock. If the stream monitoring exit releases the local lock, unpredictable serialization problems within Session Manager can occur.