Scott Bennett wrote:
On systems that distinguish clearly among userids (ahem) and especially
ones where different userids have different security privileges, tor normally
changes its userid to something specific to tor during initialization,
usually as soon as any privileged operations have completed and before any
ordinary tor operations have begun. An attempt to set the system time and
date on a system that associates privileges with userids may fail if it takes
place after tor has relinquished extra privileges.
Yes, the timing could be tricky. A cron job that check the tor log file (if configuration logs it) for time offset and set the system time could work because TOR should work even if the clock is set some time after it starts. But it is not a very elegant solution.
An hypothetical alternative method would involve tor keeping its own clock to use in the form of an offset from the system clock, but such an approach may well be impractical.
On the other hand it would work better for eg. TOR browser bundle.