librsync error: “RS_DEFAULT_STRONG_LEN” undeclared

We needed to compile an old version of rdiff-backup on CentOS 7 but got the following error:

 _librsyncmodule.c: In function â_librsync_new_sigmakerâ:
_librsyncmodule.c:63:17: error: âRS_DEFAULT_STRONG_LENâ undeclared (first use in this function)
_librsyncmodule.c:63:17: note: each undeclared identifier is reported only once for each function it appears in
_librsyncmodule.c:63:9: error: too few arguments to function ârs_sig_beginâ
In file included from _librsyncmodule.c:25:0:
/usr/include/librsync.h:370:11: note: declared here
 rs_job_t *rs_sig_begin(size_t new_block_len,
error: command 'gcc' failed with exit status 1

The librsync library changed the colling convention of `rs_sig_begin` so if you get an error like that, then a patch like this might help:

]# diff -uw _librsyncmodule.c.ORIG _librsyncmodule.c
--- _librsyncmodule.c.ORIG 2006-11-11 23:32:01.000000000 -0800
+++ _librsyncmodule.c 2018-02-20 11:22:06.529111816 -0800
@@ -59,8 +59,8 @@
 if (sm == NULL) return NULL;
 sm->x_attr = NULL;

- sm->sig_job = rs_sig_begin((size_t)blocklen,
+ sm->sig_job = rs_sig_begin((size_t)blocklen, 8,
+ (size_t)RS_MD4_SIG_MAGIC);
 return (PyObject*)sm;


Check TLS 1.2 Support: tlsv1 alert protocol version

TLS v1.0 and v1.1 to be Disabled on February 28th, 2018

As you may be aware, is disabling TLS v1.0 and v1.1 at the end of this month.  More information about the disablement schedule is available here.

You may begin to see errors like the following if you have not already updated your system:

error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version

We can help you solve this issue as well as provide security hardening or PCI compliance service for your server. Please call or email if we may be of service!

Checking for TLS v1.2 Support

Most modern Linux releases support TLS v1.2, however, it would be best to check to avoid a surprise. These tests should work on most any Linux version including SUSE, Red Hat, CentOS, Debian, Ubuntu, and many others.


To check your server, you can use this simple PHP script. Make sure you are running this PHP code from the same PHP executable that runs your website. For example, you might have PHP compiled from source and also have it installed as a package. In some cases, one will work and the other will not:

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, '');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

if (($response = curl_exec($ch)) === false) {
 $error = curl_error($ch);
 print "$error\n";
else {
 $httpcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
 print "TLS OK: " . strlen($response) . " bytes received ($httpcode).\n";



As above, make sure that you are using the same Perl interpreter that your production site is using or you can end up with a false positive/false negative test. If you get output saying “403 – Forbidden: Access is denied” then it is working because TLS connected successfully.

# perl -MLWP::UserAgent -e 'print LWP::UserAgent->new->get("")->decoded_content'
Can't connect to

LWP::Protocol::https::Socket: SSL connect attempt failed with unknown errorerror:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version at /usr/lib/perl5/vendor_perl/5.10.0/LWP/Protocol/ line 57.


To check from the command line without PHP, you can use the following which shows a failed TLS negotiation:

# openssl s_client -connect
30371:error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version:s23_clnt.c:605

Other Languages

If you use any language, we can help verify that your application is set up to work correctly.  Just let us know and we can work with you directly.  I hope this post helps, please comment below!


Naming “$@” or “$*” as values in Bash

Ever wanted $1 .. $9 to be more meaningful in a clean one-liner?

echo "$*" | ( 
	read cmd  tun_dev tun_mtu link_mtu ifconfig_local_ip ifconfig_remote_ip rest
	echo "the rest of your $cmd program and its arguments $link_mtu"
	echo "go here..."


It would be great if one could just

				echo "$@" | read a b c

but since the pipe forks the built-in shell command ‘read’, the variables $a, $b, $c are set in the sub-shell, not the shell you would want. The parenthesis force a subshell for your operation, and while its not pretty, it works quite well!

Also, thanks to Uwe Waldmann for his great Bash/sh/ksh quoting guide.



Perl script-fu: Downloading UPS Invoices

UPS provides their shipping invoices and tracking history via their website, and you can even download .CSV and .XML files. Unfortunately, they do not have an easy way to automate this process. After scouring the web for something someone else has written, I decided to write my own:

Its a terse 100 line program, and your config options are at the top of the script. It depends on WWW::Mechanize, so make sure its installed. Oh, and be forewarned: this script does not validate UPS’s SSL certificate, so I hope you trust your link to UPS 😉