as I recall we used some form of guest login on a z/os virtual machine
if I can secure such a login again for a few days I can get
the lastest to build
does ibm still have that setup?

On Mon, 14 Feb 2011 15:21:24 -0800 tom honermann wrote:
> I've been working with IBM concerning a problem we have been seeing with 
> ksh running on z/OS.  We're using the latest ksh binary available for 
> z/OS (mvs.390) downloaded from:

>     
> http://www2.research.att.com/~gsf/cgi-bin/download.cgi?action=list&name=ksh

> This version corresponds to KSH 93q+ from 2005.  Presumably, newer 
> versions of ksh do not build, or at least, are not built and made 
> available on z/OS.

> IBM has been reluctant to look into this issue because they do not 
> provide support for ksh and have no other reports of this problem 
> (described below) happening with other programs.  I have been unable to 
> find the KSH 93q+ source code available for download, so am writing to 
> see if someone might be able to make it available to me for further 
> debugging this issue.

> The problem is that ksh is failing to open a file descriptor when the 
> same file descriptor was previously used in a parent sh (not ksh) 
> process.  The problem reproduces readily using the test case below on 
> z/OS 1.8.  For anyone interested, here are the files from the test case:

> Readme.txt:

>     This test case demonstrates a defect in the z/OS /bin/sh
>     or AT&T ksh implementations, or possibly a defect in the
>     z/OS kernel.  To reproduce the problem, run './test.sh'.
>     If the problem is reproduced, the following error message
>     should be displayed:

>     $ ./test.sh
>     ./test2.sh[17]: 5: cannot open [EDC5113I Bad file descriptor.]

>     The test case consists of two shell scripts.  'test.sh'
>     attempts to delete a non-existent file using the /bin/sh
>     builtin implementation of 'rm', and then calls 'test2.sh'.
>     'test2.sh' re-execs itself using ksh and then attempts to
>     open file descriptor 5 for append to an output file.  The
>     problem appears when trying to write through that file
>     descriptor.

>     Use of the builtin implementation of 'rm' on a non-existent
>     file triggers /bin/sh to open the z/OS message catalog
>     (even though no error is displayed in this case).  The message
>     catalog will be opened as file descriptor 5 assuming no
>     unusual inherited open file descriptors.  A case was opened
>     with IBM regarding the message catalog file descriptor not
>     being closed when ksh is exec'd.  IBM confirmed that the
>     message catalog file descriptor is properly set to
>     close-on-exec.  It seems that the file descriptor is somehow
>     tainted such that ksh is later unable to write through
>     that file descriptor.

>     The version of ksh being used is the most recent available
>     from AT&T at http://www2.research.att.com/sw/download/  The
>     specific URL for downloading the z/OS version of ksh is
>     http://www2.research.att.com/~gsf/download/tgz/ksh.2005-02-02.mvs.390.gz
>     Ksh reports its version as:

>     $ ./ksh --version
>        version         sh (AT&T Labs Research) 1993-12-28 q+

> test.sh:

>     #!/bin/sh

>     # Attempt to delete a non-existent file using the shell
>     # builtin implementation of 'rm'.  This seems to be the
>     # trigger for the defect.  Commenting out this line, or
>     # changing it to use /bin/rm avoids the problem.
>     rm -f non-existent-file

>     # Ensure CONFIG_SHELL is not set
>     unset CONFIG_SHELL

>     # Run the next script
>     ./test2.sh

> test2.sh:

>     #! /bin/sh

>     # On first invocation, CONFIG_SHELL will not be set
>     if test "x$CONFIG_SHELL" = "x"; then
>        # Re-exec this script using ksh
>        CONFIG_SHELL=./ksh
>        export CONFIG_SHELL
>        exec "$CONFIG_SHELL" "$0"
>     fi

>     # Open file descriptor 5 for append to the output file
>     exec 5>>test.out

>     # Attempt to write to file descriptor 5.  If the defect
>     # is triggered, this will result in an error:
>     # <script>[line]: 5: cannot open [EDC5113I Bad file descriptor.]
>     echo "test" >&5

>     # Cleanup
>     rm -f test.out

> Tom.
> _______________________________________________
> ast-developers mailing list
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> https://mailman.research.att.com/mailman/listinfo/ast-developers

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