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Date: Thu, 18 Apr 2002 14:30:19 -0400
From: Jason Tishler <jason AT tishler DOT net>
Subject: A good way to debug LocalSystem services?
To: Cygwin <cygwin AT cygwin DOT com>
Mail-followup-to: Cygwin <cygwin AT cygwin DOT com>
Message-id: <20020418183018.GE1580@tishler.net>
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While trying to debug the following problem:

    http://sources.redhat.com/ml/cygwin/2002-04/msg00677.html

I needed to run code (i.e., seteuid()) under the LocalSystem account.
So, I used ssh to simulate su.

Specifically, I changed the SYSTEM entry in /etc/passwd to be as follows:

    SYSTEM:*:18:18:Local System,U-TISHLERJASON\LocalSystem,S-1-5-18:/home/system:/bin/bash

Then I created /home/system and copied my ssh keys to /home/system/.ssh.

After these steps, I could "su" to SYSTEM by simply executing the
following:

    $ ssh system AT tishlerjason

Now I could run strace, gdb, etc. in the context of the LocalSystem
account which really help me solve the above problem.  Maybe this is a
decent way of debugging LocalSystem services in general?  Do others agree?

Note that I found one anomaly so far.  With /etc/passwd as above, when
cron runs jt's crontab it sets $HOME to /home/system instead of /home/jt.

Jason

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