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OA34819: OpenSSH 5.0p1 Documentation Defects against SA23-2246-xx for IBM Ported Tools for z/OS: OpenSSH User's Guide

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APAR status

  • Closed as documentation error.

Error description

  • Problem #1 Description:
    
    In IBM Ported Tools for z/OS: OpenSSH Version 1 Release 2,
    OpenSSH changed how it manages user heap storage for
    data transfers.  This behavior change should have been
    documented.
    
    -------------------------------------------------------------
    Problem #1 Documentation Change #1:
    
    Book Title  - IBM Ported Tools for z/OS: OpenSSH User's Guide
    Book Number - SA23-2246-xx
    Chapter     - For system administrators
    PMR Number  - 10243,180,000
    Initials    - CW/RT
    
    Add a new "OpenSSH heap management" section that contains
    the following:
    
    While using OpenSSH, you may encounter situations where
    the user heap is exhausted when running with a limited
    amount of storage. This can be caused by certain code paths
    (for example, file transfers via sftp) in OpenSSH making
    repeated use of the XL C/C++ Run-time Library realloc()
    function. In certain situations, heap fragmentation can
    occur causing future heap allocation requests to fail and
    thus causing OpenSSH commands to fail with the following
    error message:
    
    "FOTS2050 xrealloc: out of memory"
    
    If you encounter this problem, you can do one of the
    following:
    
    1. Set the following environment variable when invoking
       OpenSSH commands:
    
       _CEE_RUNOPTS="HEAP(,,,FREE)"
    
       This will instruct Language Environment to free all
       unused storage after a call to the XL C/C++ Run-time
       Library realloc() function. This makes it unlikely
       that the user heap will be exhausted during normal
       use, albeit at a cost of reduced application
       performance. For more information about Language
       Environment heap tuning, see z/OS Language Environment
       Programming Reference.
    
    2. If running on z/OS 1.12 or later, set the following
       environment variable when invoking OpenSSH commands:
    
       _CEE_REALLOC_CONTROL="256K,25"
    
       This will instruct Language Environment to optimize
       heap storage reallocation for OpenSSH.  See
       _CEE_REALLOC_CONTROL in z/OS XL C/C++ Programming
       Guide for more information about the environment
       variable.
    
    3. Increase the amount of storage available to the
       processes running OpenSSH commands. For example,
       use a REGION of 32MB or larger and ensure that
       the IEFUSI or IEALIMIT exits are not further
       restricting the region size.
    
    -------------------------------------------------------------
    Problem #1 Documentation Change #2:
    
    Book Title  - IBM Ported Tools for z/OS: OpenSSH User's Guide
    Book Number - SA23-2246-xx
    Chapter     - Migrating to Version 1 Release 2 of IBM Ported
                    Tools for z/OS: OpenSSH
    Section     - Migration actions for IBM Ported Tools for
                    z/OS: OpenSSH Version 1 Release 2
    PMR Number  - 10243,180,000
    Initials    - CW/RT
    
    Add a new "Changes to OpenSSH heap management that might
    require a migration action" topic that contains the
    following:
    
    Description: OpenSSH changed how it manages user heap
    storage for data transfers.
    
    Is the migration action required? Yes, if you limit the
    amount of storage available to the processes running
    OpenSSH commands.
    
    Steps to take: See "OpenSSH heap management" for details.
    
    =============================================================
    
    Problem #2 Description:
    
    In IBM Ported Tools for z/OS: OpenSSH Version 1 Release 2,
    the sftp command changed how it handles subcommand parsing.
    This behavior change should have been documented as a
    migration action.
    
    Book Title  - IBM Ported Tools for z/OS: OpenSSH User's Guide
    Book Number - SA23-2246-xx
    Chapter     - Migrating to Version 1 Release 2 of IBM Ported
                    Tools for z/OS: OpenSSH
    Section     - Migration actions for IBM Ported Tools for
                    z/OS: OpenSSH Version 1 Release 2
    Topic       - Changes to the sftp command that might
                    require a migration action
    PMR Number  - 12133,180,000
    Initials    - CW/RT
    
    -------------------------------------------------------------
    Problem #2 Documentation Change:
    
    The following row needs to be added to the table.
    
    What changed
    Previously, sftp subcommand parsing handled certain
    special characters (for example, '#' and glob characters)
    differently.  Now sftp subcommand parsing is more
    consistent with shell command parsing.
    
    For more information about glob characters (also called
    wildcard characters), refer to the section on file name
    generation in the sh command description in z/OS UNIX
    System Services Command Reference.
    
    Migration action needed?
    Yes, if you use special characters on sftp subcommands.
    
    Action: Escape special characters with the backslash
    character.
    
    
    
    
    
    
    KEYWORDS:  msgFOTS2050
    

Local fix

  • N/A
    

Problem summary

  • DOC Updates
    

Problem conclusion

  • Inadequate documentation for OpenSSH heap management.  See the
    Problem Description.
    

Temporary fix

Comments

APAR Information

  • APAR number

    OA34819

  • Reported component name

    OPENSSH FOR Z/O

  • Reported component ID

    5655M2301

  • Reported release

    120

  • Status

    CLOSED DOC

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-11-04

  • Closed date

    2011-06-06

  • Last modified date

    2011-06-06

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

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

Fix information

Applicable component levels



Document information

More support for: z/OS family

Software version: 120

Operating system(s): MVS, z/OS

Reference #: OA34819

Modified date: 06 June 2011


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