2008 Jun 06 - Fri

Wt, Some Build Modifications

Back on 2007/10/03, I wrote about installing Wt (a C++ library and application server for developing and deploying web applications) on a Debian server. I've revised things a little bit since thing while building Wt v2.1.3.

In this case, I build with the newly released version of the Boost libraries: 1.35. ASIO is now included in Boost, so some build steps can be removed.

Prerequisites are little changed but for a different library for gd:

apt-get install gcc
apt-get install zlib1g
apt-get install zlib1g-dev
apt-get install libbz2-dev
apt-get install libgd2-noxpm-dev
apt-get install cmake
apt-get install libfcgi-dev
apt-get install libapache2-mod-fastcgi
apt-get install libssl-dev

The web site and repository for Wt have changed, so CVS commands will be a bit different:

cvs -d :pserver:anonymous@cvs.webtoolkit.eu/opt/cvs login
cvs -z3 -d :pserver:anonymous@cvs.webtoolkit.eu/opt/cvs co wt

I've changed the cmake/build a little bit so the results go into /usr/local/wt/include and /usr/local/wt/lib:

cmake -D DEPLOYROOT=/var/www/wt -D WEBUSER=www-data -D WEBGROUP=www-data \
-D BOOST_DIR=/usr/local \
-D BOOST_COMPILER=gcc42 \
-D BOOST_VERSION=1_35 \
-D BOOST_INCLUDE_DIR=/usr/local/include/boost \
-D BOOST_LIB_DIR=/usr/local  \
-D BOOST_DT_LIB_MT=/usr/local/lib \
-D BOOST_DT_LIB=/usr/local/lib \
-D BOOST_FS_LIB=/usr/local/lib \
-D BOOST_FS_LIB_MT=/usr/local/lib \
-D BOOST_PO_LIB_MT=/usr/local/lib \
-D BOOST_REGEX_LIB_MT=/usr/local/lib \
-D BOOST_SIGNALS_LIB_MT=/usr/local/lib \
-D BOOST_THREAD_LIB=/usr/local/lib \
-D BOOST_ASIO_INCLUDE_DIR=/usr/local/include/boost  \
-D SHARED_LIBS=ON \
-D CONNECTOR_FCGI=OFF \
-D CONNECTOR_HTTP=ON \
-D EXAMPLES_CONNECTOR=wthttp \
-D WTHTTP_CONFIGURATION=/etc/wt/wthttpd \
-D CONFIGURATION=/etc/wt/wt_config.xml \
-D CMAKE_INSTALL_PREFIX=/usr/local/wt \
.

During make install, an error regarding CMakeFiles arises. The secret, that I know, is to remove the line which includes CmakeFiles in src/Ext/cmake_install.cmake, and restart 'make install'. The install should complete normally.

The library directory /usr/local/wt/lib will need to be added to /etc/ld.so.conf, and then run ldconfig to update things.

Remember to review the Ext widgets deployment page as there are some additional files to be downloaded and installed from Ext JS.

2008 Jun 04 - Wed

PostgreSQL Upgrade 8.2 to 8.3

Back in Febrary, I wrote a longish article on how to upgrade PostgreSQL. That article is outdated. An upgrade can now take place with two lines:

pg_upgradecluster -v 8.3 8.2 main
pg_dropcluster 8.2 main

The first copies the older version 8.2 files to the new 8.3 files directory. It does any modifications necessary. The second line then removes the old stuff.

2008 Jun 03 - Tue

OpenSSH Issues

In light of the not so recent news regarding the vulnerability of openSSH in Debian, many systems have had to be patched and inter-machine keys changed.

Via Steven Rosenberg's Site I learn that a simple 'apt-get update && apt-get dist-upgrade' will update the necessary files on my system. Also in the blog entry is a reference to DRONEBL which is another black list site dealing with root compromised sites. A commenter posts the following interesting remarks about further protecting a server:

If you aren't running fail2ban or denyhosts, you should. Both will detect brute force attempts and deny connections from the attacker for a time. If you feel uncomfortable automatically banning hosts for failed logins, you can weakly configure whichever you choose to allow 20 or more failed attempts before banning. There's no reason any authenticated service should tolerate brute force attempts, in my humble opinion.

Finally, there are services, such as the DroneBL dnsbl, which have honeypot servers set up to detect brute force attempts and add them to a blacklist. You can use the "aclexec" directive in hosts.deny to query this blacklists before allowing clients to connect, to prevent connections from known brute force attackers. See http://headcandy.org/rojo/ for a suitable script to call via aclexec (view the source for the checkdnsbl script for usage instructions), and see the man page for hosts_options for more info.

Running 'ssh-vulnkey -a' showed that there were a couple keys that needed to be deleted and/or redone.

Debian has a WIKI with good information regarding the problem, affected programs, and utilities to help determine where the problems are.

If weak keys have been copied to other non-Debian hosts, the keys need to be removed from those hosts as well.

2008 Apr 24 - Thu

Installing Sun Java on Debian Lenny

Back in October last year, I mentioned how to get Sun Java installed in preparation for Eclipse. The rules have changed a bit.

You still need to put 'non-free' at the end of teh deb and deb-src lines in /etc/apt/sources.list. The secret to get the new flavour, which happens to be 1.6, is 'apt-get install sun-java6-jre' or 'apt-get install sun-java5-jre'.

Also, by default, Debian installs some other runtimes that seem to not work very well with eclipse. So to select the proper one, which was installed with the command in the previous paragraph, use 'update-alternatives --config java'.

On opening Eclipse/CDT, you may get an 'error opening the view', or some similar error regarding opening a view. The configuration above will make that error message go away.

Installing VMWare Workstation 6 on Debian Lenny

The description that helped the best, actually, the only one at which I looked, is located at eitch's blog.

It goes like this:

• cd /usr/lib/vmware/modules/source
• cp vmmon.tar vmmon.tar.orig
• sudo tar xvf vmmon.tar
• cd vmmon-only/include/
• sudo vi vcpuset.h
• change line 74 from: #include .asm/bitops.h. to: #include .linux/bitops.h.
• cd ../..
• rm vmmon.tar
• sudo tar cvf vmmon.tar vmmon-only/
• sudo rm -rf vmmon-only/
• sudo vmware-config.pl

In addition, with Debian lenny, the gcc-4.2 compiler is installed. It looks like gcc-4.1 is also installed. If both are installed, the vmware-config.pl script asks for a cpp compiler. At the prompt, supply gcc-4.1. If the compiler isn't resident, then use 'apt-get install gcc-4.1' to get it.

The installation works with the latest kernel available at the time. As headers are required for the custom vmware build, the following worked for the kernel and headers: 'install linux-headers-2.6.24-1-686 linux-image-2.6.24-1-686'.

KDE on Debian

It used to be difficult to get KDE onto a Debian installation. Everything defaulted to Gnome. In a way, it still does. If you do a standard desktop installation, Gnome is what comes up. One could use apt-get to install KDE, but that would be the hardway, and would leave Gnome residue hanging around.

The cleaner way to install KDE on Debian is to use 'install desktop=kde' at the initial boot: prompt during the installation process. While on that note, 'install desktop=xfce' maybe another alternative.

2008 Feb 19 - Tue

Installing Asterisk

Here are a few installation updates to my other installation article. Here are some revised subversion retrieval commands:

svn checkout http://svn.digium.com/svn/zaptel/branches/1.4 zaptel
svn checkout http://svn.digium.com/svn/libpri/trunk libpri
svn checkout http://svn.digium.com/svn/asterisk/trunk asterisk

The make results indicate that the trunk version of zaptel is unstable, so a 1.4 is the most recent stable version available.

make, make install, make samples, doxygen, make progdocs

Some additional, older notes can be found at AsteriskGuru.

Upgrading PostgreSQL 7.x to 8.x

Upgrading a PostgreSQL server version 7.x to version 8.x was relatively painless. It helped that there wasn't a significant amount of data to move, or blob objects to move.

For a Debian server on which I recently ran 'apt-get dist-upgrade', the Debian crew made PostgreSQL 8.2 run along side version 7.4. The /etc/postgresql/8.2/main/postgresql.conf file showed the server port as being 5433, by default. Since the service wasn't turned on, I set it for 5432, and changed the listen_addresses for '*'.

Relevant lines from the pg_hba.conf files will have to coped from the /etc/postgresql/7.x/main/ directory to the matching file in the 8.x directory. Some say that running pgadmin3 will provide messages indicating exactly which paramters need to be copied over. I havn't tried that.

The commands following are used after 'su - postgres' (logging in as the postgreSQL user account. There are a number of ways of performing backups and restores. The following sequence of steps takes a little longer, but I wield a bit more control over what gets done when.

With 7.4 running and 8.2 off, I did a 'pg_dumpall --schema-only > db.dump'. The top of the file shows a number of 'create role' lines for regenerating users.

Do a 'pg_dump databasename > databasename.db.dump' for each database (where you substitute the real name for databasename) to extract the schema and data. A 'psql -l' will list the databases available.

Use '/etc/init.d/postgresql-7.4 stop' to stop the existing service. Use 'apt-get remove xxx' to remove the various old version packages. 'apt-file -l list postg' will provide an indication of what can be removed (I'm sure there is a better way though).

Use '/etc/init.d/postgresql-8.2 start' to start the more recent version of PostgreSQL.

Use 'psql template1' to connect to the server. Run the 'create role' lines that you see from the pg_dumpall command run earlier. '\q' to exit.

Use 'createdb -T template0 --owner=ownername databasename' to create each of the databases.

Use 'psql databasename < databasename.db.dump to restore the data.

Data and schema are now ready to be used as if nothing happened.

2008 Jan 25 - Fri

Debian with Java and Eclipse/CDT

After downloading Eclipse/CDT (Eclipse for C++ Developers), and trying to run it I encountered an error about it finding Java RunTime 1.4.2, and it finding that inadequate.

I proceeded to 'apt-get install sun-java6-jre' successfully. Eclipse still didn't start. I found that if one runs 'update-alternatives --config java', one can select the proper Java Run Time with which to be running.

2008 Jan 10 - Thu

Additional Configuration Notes for Wt, a C++ Web Toolkit

I need to append some additional notes to my 2007/10/03 Wt Configuration Guide article.

As mentioned in the Wt Ext Widget deployment notes, the Wt toolkit makes use of libraries from Ext JS. There are notes at the bottom of the Wt page itemizing the files needed from the JS Ext 1.1 .zip file.

As a side note, all things Ajax can be referenced one way or another starting at the ajaxian web site. Maybe not quite the truth. More all things Ajax at AjaxPatterns... if you want to get under the hood.