[HECnet] PyDECnet setup

[Dave McGuire]

   Both Ultrix and SunOS do this in most of their major subsystems. 
Surely you've made changes to /etc/inetd.conf.

            -Dave

On 11/18/21 12:02 PM, Thomas DeBellis wrote:
> Well, I don't remember Ultrix or SunOS doing this when I was one of 
> Columbia's Unix Systems Programmers.  However, that might mean exactly 
> nothing more than I don't remember and that they did do it.  I don't 
> remember it in any daemon that I developed.  Of course, I can barely 
> remember any daemon I developed...
> 
> My dissatisfaction is not with the practice itself so much as what winds 
> up being called a standard and who says it is.  Until somebody says 
> different...
> 
> On 11/18/21 11:43 AM, Dave McGuire wrote:
>>
>>   Tom, you're describing "proper 1970s UNIX fashion".  A SIGHUP to 
>> reload/reconfigure a running process has been standard since the 
>> mid/late 1980s, perhaps even earlier.
>>
>>            -Dave
>>
>> On 11/18/21 10:50 AM, Thomas DeBellis wrote:
>>> The statement, "Proper Unix fashion", leaves me somewhat uncomfortable.
>>>
>>> Since I'm ancient, my understanding of SIGHUP is to handle a hangup 
>>> detected on the controlling terminal or the death of a controlling 
>>> process.  A hangup started out meaning dropping carrier on a modem or 
>>> DTR on a hardwired line.  It came to include a broken network 
>>> terminal connection.
>>>
>>> When I think of how to handle a SIGHUP, I usually think of 
>>> 'gracefully' stopping a process (I.E., saving the user's work instead 
>>> of ditching it) and exiting.  If you don't do that, then something 
>>> else has to be used to get rid of you, perhaps a SIGTERM.  The 
>>> problem is that if somebody wants you gone and you don't go away, you 
>>> have a 9 on your hands (SIGKILL).  Now that data is gone.
>>>
>>> If you usurp SIGHUP for such use, then things like NOHUP won't do the 
>>> expected thing.  There are certainly reasons to be NOHUP'ed.  In your 
>>> superior breaks, you might not want to disappear so somebody has a 
>>> chance to attach a debugger to you to try to figure out what happened.
>>>
>>> I think the better thing to do would be handle a SIGUSR1/SIGUSR2 to 
>>> reparse.
>>>
>>> Of course, "proper" is a very relative term in Unix.  Things change 
>>> and sometimes get used for no readily apparent reason, the result 
>>> being that an unspoken 'standard' happens.  It is not uncommon.  For 
>>> example, Johnny's DECnet bridge does in fact use SIGUSR1 to display 
>>> some information. However, it uses a SIGHUP to do a reparse.  So 
>>> maybe that's the best of both worlds...
>>>
>>> I've never felt strongly enough about the matter to suggest SIGUSR2 
>>> for a reparse, but if you want to be a purist, then it probably should.
>>>> ------------------------------------------------------------------------ 
>>>>
>>>> On 11/18/21 9:58 AM, Paul Koning wrote:
>>>>
>>>>
>>>> In proper Unix fashion it could be triggered by a SIGHUP signal
>>
>>


-- 
Dave McGuire, AK4HZ
New Kensington, PA