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Date: Thu, 9 Aug 2001 00:13:45 -0500
To: BinarySoul <binary@binary.ath.cx>
Cc: questions@freebsd.org
Subject: Re: finding user of su
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[Format recovered from top posting.] 

BinarySoul <binary@binary.ath.cx> types:
> Eric Anderson wrote:
> > Is there a tool (or how would I write one) that can tell me the original
> > user after an su?  Basically, if I su to root, how can I tell who I su'd
> > from?  
> There are a lot of ways you can do that :)
> Really...
> You can just look at you environment:
> Things like:
> id -p | grep login

Very nice. I didn't know id would do that.

> ...
> Well, I said, there are a lot of ways...
> Even:
> cat << lol > buh.c
> #include <stdio.h>
> #include <sys/param.h>
> int main(void){
>     printf("%s\n",getlogin());
>     return 0;
> }
> lol
> 
> must work

getlogin is what "id -p" uses, so the two solutions are pretty much
the same. Like all the other cases, it only works if the user doesn't
reset it. For getlogin, that needs something like this:

#include <stdio.h>
#include <sys/param.h>
int
main(int argc, char **argv) {
  if (argc != 2) {
    fprintf(stderr, "usage: %s <name>\n", argv[0]) ;
    return 1 ;
  }
  if (setlogin(argv[1]) != 0) {
    perror("olo") ;
    return 1 ;
  }
  return 0;
}


	<mike
--
Mike Meyer <mwm@mired.org>			http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.

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