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Recover name of message registered with RegisterWindowMessage()

Today I was confronted with an error in a process that would run in the background and slowly fill up the Windows message queue when it should have been dormant.

I looked at the messages that were being processed once the process woke up and the message number was 0xC10C or so. Nothing in the software has such a number. So I looked around and found out that the message was one of those created using the RegisterWindowMessage() function. (This is wrong in that application since the messages are never used from external applications, but oh well... that does not change the basic problem.)

So, ...

Turning sites and modules on and off in Apache2

I always have to looks for the command line option to turn sites and modules on and off (really it is said to be enabled or disabled.)

The commands are as follow:

  • a2ensite -- enable one site
  • a2dissite -- disable one site
  • a2enmod -- enable one module
  • a2dismod -- disable one module

When you use one of the commands in the command line terminal without specifying which site or module to enable, then you are given a list of the sites or modules you can enable or disable. Note that the configuration files have to end with .conf for this mechanism to work as expected.

Lost SSH key graphical prompt and auto-add to SSH agent

At some point in the past, my system somehow lost the ability to avoid asking me for my key every time I connect to one of my servers. It generally okay, I don't do so much work on that server that I'd have to connect all the time...

However, it is annoying when, once in while, I end up doing a lot of work, back and forth.

The ssh-agent was installed and working. I could add the key manually:

ssh-add ~/.ssh/my-secret-key
ssh-add -l

The ssh-add command allows you to add and remove keys from the ssh-agent. The -l command line option lists the keys currently held by the agent.

...

Supermicro X9SCI/X9SCA, video is gone!

As I am still trying to get my computers to work with a dual seat (or multiseat), I did an attempt in using the onboard video (a relatively decent Matrox card.) So I went in the BIOS and changed the setup for the video from Offboard to Onboard. Big mistake!

The video stopped working. On reboot the computer beeped 8 times and booted the OS normally (I have SSH setup so I could access the computer, but absolutely no video on either port: on board and off board.)

I have a Supermicro X9SCI/X9SCA. Searching for "no video" or "missing video on boot"... returned nothing ...

CRON Drupal says "HTTP/1.0 302 Found" about "/cgi-bin/ipdiags.ha" (AT&T U-Verse)

I run a few Drupal website and once per hour I run the cron.php script. I do it only once per hour because nothing changes so often on my websites so it would require faster refreshes.

Once in a while (relatively rarely now) I get a list of errors from CRON saying that the checks failed. The errors look something like this:

HTTP/1.0 302 Found
Location: /cgi-bin/ipdiags.ha
Pragma: no-cache
Content-Type: text/html

<html><meta http-equiv=Refresh content=0;url=/cgi-bin/ipdiags.ha>
<body></body></html>

As you can see, this is a 302 so a temporary error. ...

[ODBC Driver Manager] Data source name not found and no default driver specified

As I was working on a MS-Windows installation, I ran in this weird error: Data source not found and no default driver specified...

This was output when I was running the following in a command line prompt:

osql -E

The result should have been an MSSQL prompt instead!

The problem on the computer was that I uninstalled MSSQL 2005 that was automatically installed by Visual Studio C++ and was not compatible with our application, so I first uninstalled that but that uninstallation is really not proper. It leaves a LOT of things behind.

After that I installed MSSQL 2014 which was reported as ...

Adding a group for to a logged in Linux user

Once in a while I want to add my user to a group and then right away make use of that group.

Unfortunately, in general Unix kind of forces you to re-log in for the new group to be attached to your account.

However, a command has been added, a while back, to do just that on the fly. Not something you would want to use in a script, but at least, it works for me when doing a few things here and there.

In my case, I wanted to run QEMU, which I hadn't done in a while, and the system told me that it could not open the KVM, the error: kvm permission denied.

The problem was that I was not part ...

The for() in C, C++, Java, PHP, JavaScript...

As I am working on my as2js compiler, I stumble on a couple of problems with the for() loop parsing because of the in keyword. That made me think and the for() statement was actually a very funny one. Yes! You can actually write something like this and it compiles:

int zero;
for(3;2;1) zero;

As you can see, all 3 entries in the for() statement are valid expressions and therefore the compiler can compile that code. This creates a loop that runs forever, similar to:

for(;;) zero;

but much less clear to read, obviously.

Now that's food for thought, isn't it?

In JavaScript, you ...

List ciphers currently used by Apache2

If you are using Apache and e-Commerce, you probably want to know all the details of the ciphers used by the Apache SSL module.

So listing Apache supported ciphers is done using nmap as follow:

nmap --script ssl-cert,ssl-enum-ciphers -p 443 secure.m2osw.com

This call gives you a complete list of all the ciphers currently accepted by your running version of Apache. For example, the list may look like this:

| ssl-enum-ciphers:
|   SSLv3:
|     ciphers:
|       TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
|       TLS_DHE_RSA_WITH_AES_128_CBC_SHA - strong
|       ...

Repair a Cassandra Cluster

I use the Cassandra database cluster system to manage a new set of websites and once in a while I start getting many errors and the website stops working altogether.

When that happens, it is likely that Cassandra broke something in the temporary tables that it holds. The only way to go past that problem is to clear those tables. Until then, it will fail over and over again (they really would need some euristic to auto-clean up even if it means that you're losing some data.)

The command to repair the database, really quick, is as follow:

nodetool scrub snap_websites files

Note that ...

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