[Xymon] [Patch] xymond_rrd crash when parsing Linux ifconfig data

[Steve Hill]

This patch addresses two problems:

1. For Linux clients, do_ifstat_rrd parses the ifconfig output using the 
regex:
	([a-z0-9]+(_[0-9]+)?:*|lo:?)\s
pickdata() is called like this:
	pickdata(bol, ifstat_linux_pcres[0], 1, &ifname)

With a network interface name such as "foo1", the regex produces 2 results:
	0: "foo1 "
	1: "foo1"
pickdata() discards result 0 and assigns result 1 ("foo1") to the ifname 
parameter as expected.

With a network interface name such as "foo_1", the regex produces 3 results:
	0: "foo_1 "
	1: "foo_1"
	2: "_1"
pickdata() discards result 0, assigns result 1 ("foo_1") to the ifname 
parameter and then tries to assign result 2 ("_1") to the next parameter 
in the variable argument list.  Since there it no such parameter, this 
results in a segmentation fault and xymond_rrd crashes.

The attached patch adds a "num_args" parameter to pickdata() to tell it 
how many arguments are in the variable argument list and ensure it never 
rolls off the end of that list.


2. I have some clients with network interface names in the form "foo.5", 
"foo_bar" and "foo-bar" ("eth0.5" is especially common when eth0 is 
carrying an 802.1q trunk, for example).  Xymon does not collect 
statistics on those network interfaces because they don't match the 
regex.  This patch relaxes the regex a bit so that it matches these 
network interfaces.

-- 
  - Steve Hill
    Technical Director
    Opendium    Online Safety / Web Filtering    http://www.opendium.com

    Enquiries:  sales at opendium.com      +44-1792-824568
    Support:    support at opendium.com    +44-1792-825748


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    Company No. 5465437
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