Re: hooking the sept

From: Steve Richter

 

can an mi pgmr hook the sept, intercepting system calls, in a similar manner as interupts are hooked on a pc?

===> short answer: yes

 

Does the following scenario work?

 

1. the sept is a permanent system object, a space?

===> yes, type/subtype 19C3, name QINSEPT in QSYS

 

2. the sept space can be duplicated?  by CrtDupObj?

===> CrtDupObj does not recognize the object type x'19C3'

 

 by creating a user space called MySept and using CPYBWP to copy the contents of Sept to MySept?

===>this could work

 

3. when a job starts, a spcptr in the pco is set to the Sept?

===> this too could work

 

4. This pco spcptr is used as the base pointer for all subsequent access to the sept?

 

5. a job could use CPYBWP to change the spcptr in the pco to point to MySept instead of the real Sept?

===> this could work

 

6. you are then in mi heaven, able to intercept all sorts of system calls?

===> you can also simply change the SEPT directly. However that will not work from

V5R1 on, where the SEPT is write-protected.

 

 

Thanks for the help,

Steve