PK50814: UNPREDICTABLE RESULTS IF DFHPEP ISSUES SEND FOR FAILING WEB BRIDGE TRANSACTION

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• If the DFHPEP user-replaceable module issues a Terminal Control
  SEND command for a failing transaction that is using the Web
  Bridge, results are unpredictable. The state management control
  blocks that represent the simulated terminal I/O are released
  during task termination before the DFHPEP program runs, so the
  terminal simulation fails. This may cause storage overwrites or
  abends.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS Users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: If a transaction executing under the    *
  *                      CICS Web Bridge abends, and a Terminal  *
  *                      Control SEND command is issued from     *
  *                      within DFHPEP, then unpredictable       *
  *                      results may occur.                      *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  During CICS task termination, the Web Bridge termination code is
  executed before the call to DFHPEP. So if DFHPEP attempts to
  perform any terminal output, the Bridge environment is no longer
  available to perform Terminal Control simulation. This can cause
  unpredictable results, including storage overwrites, abends, or
  even CICS termination.
  Even if none of these happen, the message issued by DFHPEP is
  not transformed into HTML by the Bridge, but an HTTP 500
  Internal Server Error message is produced instead.
  

Problem conclusion

• The timing of the execution of Web Bridge termination function
  is made conditional on whether task termination is normal or
  abnormal. For normal termination, Web Bridge cleanup continues
  to be executed prior to Recovery Manager termination, so that
  pending simulated output can be preserved for subsequent
  transactions in a pseudo-conversation. But for abnormal
  termination, the Web Bridge cleanup is deferred until after
  abnormal condition reporting (which invokes DFHPEP) but before
  syncpoint rollback.
  
  Also, an error in formatting the CSS section of the HTML prolog
  output by the Web Bridge has been corrected.
  
  In "CICS Transaction Server for z/OS Data Areas", GC34-6863-00,
  the TCTTE will be updated and the following:
  
  | Offset | Type      | Len     | Name     |Description |
  | Hex    |           |         |          |            |
  |------------------------------------------------------|
  | (CC)   | BIT(8)    | 1       | *        |            |
  |------------------------------------------------------|
  |        | 11.. .... |         | *        |            |
  |------------------------------------------------------|
  
  will be replaced with:
  
  | Offset | Type      | Len     | Name     |Description |
  | Hex    |           |         |          |            |
  |------------------------------------------------------|
  | (CC)   | BIT(8)    | 1       | *        |            |
  |------------------------------------------------------|
  |        | 1... .... |         | *        | Reserved   |
  |------------------------------------------------------|
  |        | .1.. .... |         | TCTTEPEP | DFHPEP is  |
  |        |           |         |          | executing  |
  |------------------------------------------------------|
  
  
  In "CICS Transaction Server for z/OS Supplementary Data Areas",
  GC34-6864-00, the WBSTC (Web State Manager Data) will be
  updated with the following new fields
  
  | Offset | Type      | Len     | Name        |Description |
  | Hex    |           |         |             |            |
  |---------------------------------------------------------|
  | (57)   | BIT(8)    | 1       | WBSTU_      |            |
  |        |           |         | TASK_STATE  |            |
  |---------------------------------------------------------|
  |        | 1... .... |         | WBSTU_DFHPEP|            |
  |        |           |         | _SENT_MSG   |            |
  |---------------------------------------------------------|
  |        | .111 1111 |         | *           |            |
  |---------------------------------------------------------|
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

• ž**** PE09/01/22 FIX IN ERROR. SEE APAR PK79173  FOR DESCRIPTION
  ž**** PE09/01/22 FIX IN ERROR. SEE APAR PK79173  FOR DESCRIPTION
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UK31156

Modules/Macros

•    DESDHDH  DESWBLT  DESWBST  DESWBTCC DESWBTTA
  DESXMAT  DFHDHDH  DFHDHPB  DFHDHPD  DFHDHPM  DFHDHPS  DFHDHPT
  DFHDHPU  DFHDHPX  DFHTCTTE DFHTCTZE DFHTFP   DFHWBLT  DFHWBST
  DFHWBSTC DFHWBSTD DFHWBTCC DFHWBTTA DFHXMTA
  

Fix information

• Fixed component name

  CICSTS V3 Z/OS

• Fixed component ID

  5655M1500

Applicable component levels

• R500 PSY UK31156

     UP07/11/15 P F711

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.