On 17 December 2013 14:38, Don Poitras <[email protected]> wrote: > I don't see why someone couldn't install their own table in place > of the pointed to by the CVT. See > > http://pic.dhe.ibm.com/infocenter/zos/v2r1/index.jsp?topic=%2Fcom.ibm.zos.v2r1.bpxb100%2Fbpx2cr_Example.htm
Sure - I agree that that's not hard. But, as with SVC screening, you have to eventually pass control on to the real routine (or conceivably fail the call or implement a different version yourself). If all you want to do is log the calls, well it's probably not too hard, though you might have to be aware of the caller's environment. If you want to do all this without introducing security or integrity exposures, you may have to analyze each call you want to capture. It may also be the case that some software "just knows" the PC numbers for certain routines, and doesn't go through the CSR table at all. Not a good practice, but I'd be surprised if it doesn't exist. And who knows what recovery and repair there may be in the UNIX kernel, or if those tables are dynamically updated as a matter of routine. This would be fun to experiment with on your own private LPAR or zPDT, and I'm not saying it can't or even shouldn't be done, but is anyone really going to install such a change into their production systems? That's why I said it falls into the "not for the faint of heart" category. Tony H. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
