Application Exceptions When Opening a SNA Server 2.11 COM.CFG

The information in this article applies to:

• Microsoft SNA Server version 3.0 and 3.0 SP1

SYMPTOMS

An SNA Server 3.0 system may generate an application exception in an SNA Server module when you try to open an SNA Server 2.11 configuration file.

This only occurs if the SNA Server 2.11 configuration contains duplicate LU numbers on a particular connection for a 3270 LU and a dependent LU 6.2 LU.

This problem has been observed to cause application exceptions in the SnaBase service and in SNA Server Manager (Snaexp.exe).

CAUSE

When SNA Server opens a configuration file (Com.cfg), it does two checks on 3270 LUs. The first check ensures that the LU number is unique among all 3270 LUs on a connection. The second check is used to look for LU number conflicts between 3270 LUs and dependent APPC LUs configured on a server. If either of these fail, the LU record is destroyed and an error variable set.

The application exception occurs because the second check is being performed without regard to the error code being returned by the first check. This results in a destroyed LU record being passed to the test routine, causing the application exception.

STATUS

Microsoft has confirmed this to be a problem in SNA Server versions 3.0 and 3.0 SP1. This problem was corrected in the latest SNA Server version 3.0 U.S. Service Pack. For information on obtaining this Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K

MORE INFORMATION

When this problem occurs, a Drwtsn32.log containing information similar to the following will be generated in the Windows NT directory:

   Application exception occurred:
        App: exe\snabase.DBG (pid=<process id>)
        When: <date> @ <time>
        Exception number: c0000005 (access violation)

   function: ConflictingLocalLuNumbers
      6120bf4e 53               push    ebx
      6120bf4f 56               push    esi
      6120bf50 57               push    edi
      6120bf51 8b7c2414         mov     edi,[esp+0x14]
   ss:031de38f=????????
      6120bf55 55               push    ebp
      6120bf56 50               push    eax
      6120bf57 57               push    edi
      6120bf58 66bd0100         mov     bp,0x1
      6120bf5c e85f1b0000       call    GetAddr (6120dac0)
      6120bf61 8bd8             mov     ebx,eax
   FAULT ->6120bf63 8b406c           mov     eax,[eax+0x6c]
   ds:01beea06=????????
      6120bf66 50               push    eax
      6120bf67 e874f0ffff       call    GetGrpCount (6120afe0)
      6120bf6c 6689442412       mov     [esp+0x12],ax
   ss:031de390=????
      6120bf71 663bc5           cmp     ax,bp
      6120bf74 7244             jb      ConflictingLocalLuNumbers+0x7a
   (6120bfba)
      6120bf76 668b74241c       mov     si,[esp+0x1c]
   ss:031de390=????
      6120bf7b 55               push    ebp
      6120bf7c 8b436c           mov     eax,[ebx+0x6c]
   ds:01beea06=????????
      6120bf7f 50               push    eax
      6120bf80 e88bf0ffff       call    GetGrpNthItem (6120b010)
      6120bf85 50               push    eax