RE: thread-safe support of snmpd

Hello,

Talking about multithreads...

I wonder, how can I implement sending traps in agent, triggered from some
other thread that listen independent events?

In other words: I have snmpd thread that reacts on snmpXXX events. Where and
how in the agent I should add code that also sends traps depending on the
external event in the system checks (periodicaly/asynchronously) some
status?

Thanks in advance,
Igor G.


Igor Grasic, Ms. D.
Development Engineer
Iskra Transmission, d. d., Ljubljana
Stegne 11, SI-1000 Ljubljana, Slovenia
phone: +386 1 5003 000
fax: +386 1 5003 500
www.iskratr.si, www.iskratr.com






From: Toth, Gregory S <gregory@bo...>
RE: thread-safe support of snmpd
2005-03-28 09:04

You can also wrap all calls to the net-snmp api with mutex"s

-----Original Message-----
From: Robert Story [mailto:rstory@fr...]
Sent: Monday, March 28, 2005 8:44 AM
To: lglyahoo-misc@ya...
Cc: net-snmp-coders@li...
Subject: Re: thread-safe support of snmpd


On Mon, 28 Mar 2005 18:38:31 +0800 (CST) lglyahoo-misc@ya...
wrote:
LMCC> Since there are at least two threads running in
LMCC> snmpd: the main thread which handles SNMP requests and the event
LMCC> listening thread, we must make sure snmpd could run thread-safely.

No, snmpd is not thread safe.

LMCC> I use callback mechanism(SNMP_CALLBACK_LIBRARY and
LMCC> SNMP_CALLBACK_SESSION_INIT) to let snmpd create a
LMCC> thread which will listen user defined events and
LMCC> update the global cache or generate traps according to the
LMCC> analysis of these events. The global cache is user defined and
LMCC> it"s used in the MIB handlers.

The only way to use snmpd in a multi-threaded application is to keep ALL
snmp functionality in ONE thread. Other threads may listen for non-snmp
related events, and notify the snmpd thread that a trap needs to be
sent, but the trap itself must be sent from the snmpd thread.

--
Robert Story; NET-SNMP Junkie
Support: <http://www.net-snmp.org/> <irc://irc.freenode.net/#net-snmp>
Archive:
<http://sourceforge.net/mailarchive/forum.php?forum=net-snmp-coders>

You are lost in a twisty maze of little standards, all different.


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