winapi - Change the value of a MSI property loaded from a DLL using a MSI transform

Question

I need to modify the installation behavior of a MSI setup for "IBM i Access for Windows". The setup was created using InstallShield. During the installation the setup triggers two other MSI installations through "chaining". The parameters passed to MSIEXEC.EXE to execute those two installations get loaded by a custom action from a DLL that is included with the installation. The parameters end up in a MSI property.

I want to change the value in that property to manipulate the command line before the chained installation gets launched. Is this possible? If so, how? I have no problem to create an external DLL that reads and modifies the property, but I am at a loss on how to integrate this with the existing installation -- which tables do I have to modify and how, where should I put the DLL, ...

EDIT 1: To clarify this: I want to modify the parameters passed to the chained MSI installations. They are independent from the parameters I pass to the main installation and are loaded from a DLL that is part of the installation.

EDIT 2: I have uploaded the plain MSI + the relevant log file. I start the main installation with "/qn" to suppress all messages. That works without problems, the chained installations get executed without visible prompts. The problem arises when uninstalling the software (again with "/qn"). The remote custom action gets loaded from a DLL (line 6417):

MSI (s) (10:28) [09:00:45:643]: Invoking remote custom action. DLL: C:WindowsInstallerMSIA4BD.tmp, Entrypoint: ISChainPackages

The command line loaded from the DLL specifies to call MSIEXEC.EXE with the parameter "/qb" instead of "/qn" (line 6958):

MSI (s) (10!60) [09:00:46:033]: PROPERTY CHANGE: Adding IS_CHAINER_POST_COMMANDLINE property. Its value is '/l"c:empIBM_iAccess_7.1_Uninstall.log" /qb /x{CCA40632-843E-48C6-B14F-E1070015D87C} ...

And because the MSI installer has a lock on a file a messagebox pops up triggered by the uninstallation of the chained MSI (line 44046):

MSI (s) (10:C0) [09:01:05:553]: RESTART MANAGER: Did detect that the custom action server with process ID 2352 holds file[s] in use, so a reboot will be necessary.
MSI (s) (10:C0) [09:01:05:553]: Note: 1: 1610 
MSI (s) (10:C0) [09:01:11:224]: RESTART MANAGER: The user chose to go on with the installation, although a reboot will be required.
The setup must update files or services that cannot be updated while the system is running. If you choose to continue, a reboot will be required to complete the setup.

The installation files for version 7.1 of this software are no longer available on the IBM website. Only the current version is, and I have not looked into whether the problem still exists with the latest version or not as I have been asked to package v7.1 by the business department.

Answer 1

One approach to this problem would be to create a new Custom Action that executes VBScript code stored in the Binary Table and place the new Custom Action right after ISChainPackagePrepare. The VBScript code will read the value of IS_CHAINER_POST_COMMANDLINE and replace it as specified in the Replace() function

The VBScript Code could look like this:

Option Explicit

Function ReplacePropVal()
    dim propvalue
    dim newvalue
    propvalue = Session.Property("IS_CHAINER_POST_COMMANDLINE")
    newvalue = Replace(propvalue,"/qb","/qn")
    Session.Property("IS_CHAINER_POST_COMMANDLINE") = newvalue
End Function

You want to give your new Custom Action a Type of 6 to indicate that your Custom Action data is stored as a VBScript in the Binary table. Your Custom Action Source is a reference to the Name in the Binary Table. The Target value of your Custom Action will need to be the name of the VBScript Function which is ReplacePropVal in this case

Afterwards, you place your new Custom Action in the InstallExecutionSequence table using the same name for it as in the CustomAction table. Also make sure to give it a higher Sequence value as ISChainPackagePrepare. I would recommend placing it right after by incrementing the Sequence value of ISChainPackagePrepare by 1.

After you've changed the tables and generated a new transform, just run the package with the new transform being applied by specifying its path in the TRANSFORMS public property and your property value should be changed.