[mod.computers.vax] Changing username on the fly

Michael J. Porter@SRI-KL.ARPA:mike%udel-oitvax.arpa@Louie.UDEL.EDU (11/14/86)

	Date: Thu 13 Nov 86 17:50:24-EST
	From: John Hanley <OC.HANLEY%cu20b.columbia.edu@louie.udel.EDU>
	Subject: DECUS C and dynamic username changes

	Is there anyone on DECnet reasonably close to Columbia that could send
	me with huge physical memory requirements (ie, Lisp).  Your kernel mode
	routine could blank out the last 2 characters of a 10 character username
	(I think) with something like
	        MOVL @#SCH$GL_CURPCB, R0
	        MOVW #^X2020, PCB$T_LNAME+10(R0)
	Later, when you finish talking to the IBM, do a $GETUAI and another

                                   John Hanley, system programmer
                                   Manhattan College Computer Center
                                   Box 902, Manhattan College
                                   Riverdale, NY   10471
                                   (212)920-0424
                                   oc.hanley@cu20b
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Close, but you must change the Process's control region as well if you
want to change the user name.  I once wrote some code that only changed
the PCB, and some service out there kept copying the name in the
control region into PCB - it was real strange.  Anyway, change
CTL$T_USERNAME.  As the above code illustrates, make sure you use absolute
addressing as well, or your code will not work.

				Mike Porter

mike%udel-oitvax@louie.udel.edu
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