[Xymon] rrd logs and graphs

[Jeremy Laidman]

On 11 March 2015 at 11:37, Vernon Everett <everett.vernon at gmail.com> wrote:

> And even with --no-cache, I am still getting these corrupted rrd files.
>

:-(


> I tried again with --debug (and --no-cache) and it core dumps.
>
> Here's the backtrace.
>


> libc.so.1`vfprintf+0xec(6c3d0, 514c0, ffbfb3e8, 0, a0ba4, 33e1c)
> dbgprintf+0xa4(514c0, 0, 51400, 6c3f0, bf, 2ab388)
> dump_tcp_services+0x74(a0, 1c00, fef37940, 0, 51400, 51400)
>

So dump_tcp_services() calls dbgprintf() (both on lib/netservices.c) which
in turn calls vprintf() from libc, but with bad parameters.  I've had a
look through the code in dump_tcp_services() and I don't know enough C to
recognize any problems.  But it might be useful to know which call to
dbgprintf() is causing the problem.

Does the log file for xymond_rrd show any debug output at all?  If so,
what's the last line that is shown.

It might be helpful if you can recompile xymond_rrd with
dump_tcp_services() modified.  Initially, I would simply try it with
"return" added after the first call to dbgprintf().  That is,
dump_tcp_services() will output "Service list dump" and return.  This might
stop the core dumps so that we can get debug output for other parts of the
xymond_rrd processing.

If adding "return" at that point fixes this core dump, more diagnostic
lines would be useful to determine what the problem is.  For example,
there's a global array called svcinfo that is iterated over, but if the
array is empty, it might cause the core dump.  So adding a line that checks
whether the array is empty and displays the result would help to pin this
down.

Note that "svcinfo" appears to be populated from the protocols.cfg file
and/or XYMONNETSVCS.  Is it possible that your protocols.cfg file is empty,
or has some syntax error that causes it to be unparseable?  The same for
XYMONNETSVCS (in xymonserver.cfg)?

J
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