Access to structure in <sys/user.h>

apn apn at nonvon.UUCP
Fri Dec 26 13:53:49 AEST 1986


In article <96 at osupyr.UUCP>, dusan at osupyr.UUCP (Dusan Nedeljkovic) writes:
> Does anyone have any clues as to how to access the "user" structure
> in <sys/user.h> ?
> 
> I need to find information concerning the status of a users process
> for a C program I will be writting.  Any help on where to find this
> information (or am I on the wrong track?) would be highly appreciated.
> 
> 

Reading user struct from C program.

a simple outline:


	1] find your process descriptor table entry in ram
		by reading from /dev/mem and filling proc structure
	        ( see <sys/proc.h> )

	2] determine from the entry that is yours, what the address
		of your process is and what device it is on at the
		moment.  Should either /dev/mem or /dev/swap or for those
		lucky few of us /dev/swmem

		address of your user struct should be determined
		from something like :

		(again, this is highly dep. on your CPU, MMU, etc)
		(this is for 68k w/ 68451 MMU                    )

		addr = ctob((long) proc_p.addr) for /dev/swap 
		addr = proc.p_addr + swplo << 9; for /dev/swmem

	3] seek to addr in /dev/(fill in appropriate device)
		and read something the size of your user structure

	4] <done>


Note that all this requires read access to /dev/mem, etc. And thus
may defeat your purpose. Take this only as an outline. Mileage will
vary considerable with flavor of UNIX. This was from sV.   

Other than those caveats.... I hope this is of some help.

	uucp: ptsfa!nonvon!apn





		
	
-- 

	UUCP:   ihnp4!ptsfa!nonvon!apn

		100 Drakes Landing Road
		GreenBrae, CA 94904
		+1 415 461 4655

{* War does not determine who is right or wrong........ only who is left   *}
{* Only those who attempt the absurd   ...   will achieve the impossible   *}
{* I think... I think it's in my basement... Let me go upstairs and check. *}
{*                                                      -escher            *}
{* System down for P.M. until further notice                               *}



More information about the Comp.unix.questions mailing list