On Tue, 4 Apr 2006 15:34:54 -0700 Ray Mullins <[EMAIL PROTECTED]> wrote:
:>If you mean the old :>save-the-current-address-and-stick-my-address-in-the-table-and-then-pass-con :>trol-to-the-old-routine-when-I'm-done-with-it method... :>A product that utilizes SVC screening should check to see if screening is :>already in place, i.e., the existence of a screening table in the TCB. It :>should then save the address of the already existing routine somewhere in :>its storage, store its address in the screening area, save the current :>table, and flip on the bits for the SVC that it wants to screen - and not :>flip off any bits. Then, if its code gets control for an SVC that it isn't :>expecting, it knows that there is another screening routine that might want :>it, so it should pass it on to the routine whose address it saved at :>initialization. And for SVCs that the new routine does screen, when it's :>done it should then check the old SVC screening table to see if the prior :>SVC routine wants it. :>Sort of wordy, but hopefully the point is somewhat clear. That approach will work when the SVC type is the same (or similar) and the locks can be merged. I am more curious as to the application, i.e., why does vendor code - unexpectedly - need to use SVC screening on an arbitrary TCB? Why would two products wish to mark the same TCB? Also, why not actually frontend/replace the SVC? - certainly less muss and fuss! :>> -----Original Message----- :>> From: IBM Mainframe Discussion List :>> [mailto:[EMAIL PROTECTED] On Behalf Of Ira Broussard :>> Sent: Tuesday April 04 2006 15:23 :>> To: IBM-MAIN@BAMA.UA.EDU :>> Subject: SVC Screening -- again :>> I searched the archives for SVC screening posts and saw quite :>> a few postings regarding when to use it and what to use it :>> for. What I am looking for (and didn't find in the archives) :>> is how multiple screening programs are implemented. For :>> example, what if products from different vendors want to do :>> SVC screening on the same TCB? Is there a de facto method :>> that vendors use similar to the one used for front-ending SVC's? -- Binyamin Dissen <[EMAIL PROTECTED]> http://www.dissensoftware.com Director, Dissen Software, Bar & Grill - Israel Should you use the mailblocks package and expect a response from me, you should preauthorize the dissensoftware.com domain. I very rarely bother responding to challenge/response systems, especially those from irresponsible companies. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
