Dear SCO Customer,

Support Level Supplement (SLS) ptf7051f, the UnixWare 7.0.1 libc Patch,
corrects these known problems with the libc library on UnixWare 7.0.1:

   1. Certain functions are not available in the dynamic version of libc,
      and this prevents an application's own shared libraries from using
      these functions.  SLS ptf7051f moves the following functions into
      the dynamic version of libc:  ecvt, fcvt, fstat32, fstat64, lstat32,
      lstat64, stat32, stat64, and syscall.

   2. The JDK java.net.Socket constructor does not throw an exception
      when the socket connection fails under certain conditions.

Note: This SLS only partially addresses problem #2 above.  If you are using
      SCO JDK 1.1.3w, you also need ptf7096 (STREAMS).  If you are using
      SCO JDK 1.1.3u, you need ptf7096 (STREAMS) and ptf7122b (JDK).

      To verify which version of the JDK you have, run "pkginfo -l jdk113"
      and look at the VERSION field in the output.  The latest version of
      the JDK can be downloaded from:

             http://www.sco.com/java

      A fix for problem #2 also exists for SCO UnixWare 2.1.3 in SLS ptf4026d.

   3. The select function does not support more than 64 sockets.  An attempt
      to use more than 64 sockets in a call to select returns with an EBADF
      error.

      This symptom may manifest itself in different ways, depending on the
      application.

      For example, while running a RealNetworks Internet Server the following
      behavior may be encountered:

             - All client connections are dropped once a threshold
               has been reached, usually around 60-70 connections.

             - An unexpected limitation of the number of clients
               that can connect may be reached.  In some cases the
               more recent connections may appear to hang.

      Symptoms similar to the ones listed may be addressed by SLS ptf7051f.

   4. A "bad file number" error message may be returned by select after the
      descriptor is closed. This has been corrected through modifications to
      select(3C). select(3C) will now only send an exception if one is 
      requested.

New in SLS ptf7051f:

   5. The pt.c functions have been enhanced to support up to 99999 ptys.
      Previously, the Unix98 pty support routines could not allow more than
      999 ptys to be allocated by a user process.

   6. SLS ptf7051f addresses a security vulnerability in the localization 
      code in libc.

      Note: SLS ptf7073c must also be installed for a complete solution 
            to this issue.
  

SLS ptf7051f contains:

        /usr/ccs/lib/libc.so
        /usr/ccs/lib/libc.a
        /usr/ccs/lib/libp/libc.so
        /usr/ccs/lib/libp/libc.so.1
        /usr/ccs/lib/libp/libc.a
        /usr/lib/libc.so.1


Software Notes and Recommendations
----------------------------------

SLS ptf7051f should only be installed on:

        UnixWare 7 Release 7.0.1

This SLS should be installed prior to installing the Java Development Kit
(JDK) Release 1.1.3w on systems running UnixWare 7.0.1.

SLS ptf7051f now also incorporates modifications to the select(3C) call.

SLS ptf7073c must also be installed for a complete solution to the
security vulnerability noted above. 

SLS ptf7051f supersedes, and contains all fixes from, previous versions 
of ptf7051.


Installation Instructions
-------------------------

1. Download the ptf7051f.Z file to the /tmp directory on your machine.

2. As root, uncompress the file and add the SLS package to your system
   using these commands:

        $ su
        Password: <type your root password>
        # uncompress /tmp/ptf7051f.Z
        # pkgadd -d /tmp/ptf7051f
        # rm /tmp/ptf7051f

3. Reboot the system after installing this SLS package.

The release notes displayed prior to installation can be found in:

        /var/sadm/pkg/ptf7051/install/ptf7051.txt


Removal Instructions
--------------------

1. As root, remove the SLS package using these commands:

        $ su
        Password: <type your root password>
        # pkgrm ptf7051

2. Reboot the system after removing this SLS package.

If you have questions regarding this SLS, or the product on which
it is installed, please contact your software supplier.