DAEMONS !!!

DAEMONS !!!

Post by Sunil kumar Vallamkon » Sat, 19 Mar 1994 07:32:39



A wake-up question to Unix netter GURUS !!!!!!

The book "Unix System V Programming" by Stephen A. Rago says
in creating a deamon (Page 84) as following steps:

1) create a log file
2) Get the max nof of files we can open
3) Become Session Leader to lose our controlling terminal
        QUESTION:
        What does this exactly mean ?
        What is a controlling terminal and how does one first of all,
        associate a controlling terminal to a process, etc ??

        In his eg., he forks and kills the parent and then calls
                setsid().
        Is there any other way of becoming a session leader ??

4) Ensure that future opens will not allocate controlling terminals.
        QUESTION:

        For this step again, he forks and kills parent process !!

        Is this really required and if so, is there any other way of
        doing this ??

I shall appreciate if any one enlighten me on Daemons in Unix !!!
Any other material(s), suggestions, re: this topic will be of good help to me.

Thank you !!!

 
 
 

1. SNMP daemon not active on port 161 (or anywhere); daemon loaded.

I'm running RedHat 5.0+ (Updates to 5.0, but not a 5.1 fileset) and
I've loaded cmu-snmp.  I've edited /etc/snmpd.conf, though it's supposed
to work without changes, and I'm not getting any responses (even error
messages) from port localhost:161.

    Some issues:

    1. I'm using strobe to check ALL ports that might be listening.
This works for lpr, www, and all the better known protocols, but
wouldn't it show up if snmpd was set up properly?  (Otherwise I can't
really check it's operation.)

    2. Is there any authentication that I might be overlooking, simply
to look at the public MIBs?  I know there's authentication for writing
(anywhere) and reading private ones.

    All I want is enough of SNMP to work so that I can build my
understanding of it.  I've tried scotty; it worked even less than CMU.
I spent two hours last night trying to get their browser (tkined) as a
seperate package to no avail.  At least with  CMU I have parts the
ostensibly work without my learning SNMP AND Tcl/TK all at the same
time.

    I just don't have enough 'parts' that work enough to tell if I can
even use the final result.  Usually this would be because I lacked a
certain library file that the tarball needs...but I'm installing by RPMs
here, RPMs that SHOULD have been packed by someone who knows when the an
implementation of SNMP is working.  (He'd know better than I).

    One more thing...did someone forget the first word of the SNMP
acronym?  Simple?  There are tons of subsets for this technology.  There
are agents that can only send a value (and only one) after receiving a
single request....and there are superior agents that will answer
anyone's request no matter how many times it's asked. (Asynchronous
traps.)  The funny thing is, CMU uses synchronous traps, and IT'S
declared the standard.

    At what point does the 'simple' kick in?

    Brian

--------------------------------------------------------------------------------
Brian Fahrlander                       Problem Solver, Technomad, and
Linux-head
Evansville, IN
ICQ:5119262                                          
http://www.kamakiriad.com
--------------------------------------------------------------------------------
 Whitewater isn't over until the First Lady sings.

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