RFE: Enhance upsd to LISTEN host:port with one colon-separated parameter token

[jimklimov]

tcp6 0 0 :::3493 :::* LISTEN 1447/upsd
I remember being surprised by the space in the LISTEN directives ...

Thinking of it... might make sense to parse a single token on a LISTEN <token1>:<token2> (with at least one colon character), as an addr-colon-port so spelling of LISTEN :::3493 would get split into :: and 3493, and some LISTEN 127.0.0.1:3493 would become 127.0.0.1 and 3493.

That said, in ~25 years of NUT's existence I think this is the first time such issue was raised (to the best of my personal knowledge) - so I guess it is a rare surprise after all the RTFM :)

Originally posted by @jimklimov in #2417 (comment)

UPDATE: This could be easy in the server-side code; most of the problem would be to teach nutconf, augeas and similar upsd.conf parsers about two acceptable spellings.

UPDATE: While at it (although a separate issue): is there any perceived need to parse the port part (if its string is not representing a number) through the naming database for services to e.g. LISTEN localhost nut?

CC @aquette @clepple : WDYT ?

[jimklimov]

For kicks, tried if it would just work - no, it does not; the whole single/first token is seen as an address, and the lack of second token causes an attempt to use the default port number:

:; rm -rf /tmp/nnnn ; mkdir -p /tmp/nnnn && touch /tmp/nnnn/{ups.conf,upsd.conf,upsd.users}
:; echo 'LISTEN :::3493' > /tmp/nnnn/upsd.conf
:; ALLOW_NO_DEVICE=yes NUT_STATEPATH=/tmp/nnnn NUT_CONFPATH=/tmp/nnnn ./server/upsd -DDDDDD ; echo $?
Network UPS Tools upsd 2.8.2-137-g3c19d79de
   0.000001     fopen /tmp/nnnn/upsd.pid: No such file or directory
   0.000043     Could not find PID file '/tmp/nnnn/upsd.pid' to see if previous upsd instance is already running!
   0.000208     /tmp/nnnn/upsd.conf is world readable
   0.000333     [D3] listen_add: added :::3493:3493
   0.000373     [D1] debug level is '6'
   0.000413     [D3] setuptcp: try to bind to :::3493 port 3493
   0.000530     getaddrinfo: Name or service not known