Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!columbia!rutgers!sri-spam!mordor!lll-tis!ames!ucbcad!ucbvax!ditmelb.OZ.AU!SMART From: SMART@ditmelb.OZ.AU (Robert Smart) Newsgroups: comp.os.vms Subject: Disassembly, NOTRACEBACK, dynamically loaded shareable images Message-ID: <8706300437.AA02504@seismo.CSS.GOV> Date: Tue, 30-Jun-87 16:38:44 EDT Article-I.D.: seismo.8706300437.AA02504 Posted: Tue Jun 30 16:38:44 1987 Date-Received: Thu, 2-Jul-87 00:38:12 EDT Sender: usenet@ucbvax.BERKELEY.EDU Distribution: world Organization: The ARPA Internet Lines: 19 It is quite easy to change an image linked /NOTRACEBACK to be debuggable: PATCH/ABSOLUTE x.EXE and set the low order bit of location 20 (this seems to mean changing 01000028 to 01000029). Now set the longword at 34 (which is 0) to the contents of the longword at 30. Now set the longword at 30 to be the correct start address for the debugger: currently 7FFEDF68. Update and exit and you've done it. I hoped to use this trick to debug a dynamically loaded shareable image (a protocol handler for MAIL). Does anybody know how to tell the debugger that a shareable image has suddenly arrived at a particular address? I would prefer it if the debugger would notice arriving shareable images itself, but perhaps that is asking too much. Robert Smart, CSIRO Division of Information Technology, Australia