The hackweek project I worked on was to implement a live graphing utility for per process I/O data. See https://features.opensuse.org/306941 (Yes, I added the fate request, just now, after doing most of the work.)

Screen-shots, RPM download link, project homepage link,..

The main idea behind choosing to work on this was to do some GUI programming on a modern language. I work on the linux-kernel(so no gui) and most of the time I write ‘C’ programs.(In fact, at times even when bash would be appropriate!)

So I decided to do this and had to choose between moonlight and Java. My experience with C# was nil, and moonlight was an applet/flash equivalent not aimed at desktop apps.(Yes, there are desktop applications in flash. Even mono has mopen) I thought that I would have to access procfs and might also need to do netlink sockets and moonlight could be a problem. And the real benefit of flash is the the IDE/designer for development, which anyway moonlight is yet to get. In the end, I chose Java.(was a tough fight with C# but again gtk# versus winforms…)

And here it is..

watching dd...

Watching vlc reading from disk as I seek

You can download it from http://download.opensuse.org/repositories/home:/nikanth/ The source is also available at http://gitorious.org/ullae-veliyae/

RPM quick Links:

http://download.opensuse.org/repositories/home:/nikanth/openSUSE_11.1/i586/ullae-veliyae-1.0-11.1.i586.rpm

http://download.opensuse.org/repositories/home:/nikanth/openSUSE_11.1/x86_64/ullae-veliyae-1.0-11.1.x86_64.rpm

[Yes, it should be made as no-arch! ;)]

chaos

If you are trying it out, see whether you can find an easter egg? [Yes, it is kind of lame to have easter-eggs on a open-source project with just hundreds of LOC] The easter egg is an hidden functionality.

I should thank Vojtech Pavlik, for his very useful ideas of “history”, such that we can squeeze the historical data and keep it for longer duration. And another idea of showing average of the data instead of current data, as it tends to be spiky. I haven’t implemented rolling-window for the average though.

A picture is worth 1000 words, but trying it out yourself is worth much more than that.  So play with this once.

Gran Canaria Desktop Summit has been great and really productive. I had the pleasure to meet people interested in QJson, chat with them but also hack with them.

In fact we hacked a lot, doing lots of changes to QJson:

• the API has been cleaned, now it can be considered stable
• unicode support has been completely rewritten
• it’s now possible to convert QVariant objects into JSON ones
  

So it’s with a great pleasure that I announce the release of QJson 0.6.0.

Beware, since the API has been changed your application will probably break. I’m really sorry about that, but I guarantee it won’t happen in the future (as I said both API and ABI interfaces can now be considered stable).

QJson web site has been updated, reflecting all the changes made to the library. openSUSE packages has been moved from my home repo to KDE:Qt one.

One last note, if you have problems with QJson please contact me using the qjson-devel mailing list. You can subscribe here.

Call for contribution

FAQ's

Libstorage is a C++ library for managing Linux storage devices. So far it was developed as part of YaST but since a few weeks it is an independent project.

Here is a code example creating a 1GB partition on /dev/sdb.

  Environment env(false);
  StorageInterface* s = createStorageInterface(env);

  string name;

  // Create 1GB partition on /dev/sdb and format it with Ext4.
  s->createPartitionAny("/dev/sdb", 1048576, name);
  s->changeFormatVolume(name, true, EXT4);

  // Set mount-point to "/home" and fstab option to "relatime".
  s->changeMountPoint(name, "/home");
  s->changeFstabOptions(name, "relatime");

  // Set filesystem label to "HOME" and mount filesystem by label.
  s->changeLabelVolume(name, "HOME");
  s->changeMountBy(name, MOUNTBY_LABEL);

  // Commit the change to the system. This will create the partition,
  // format and mount it and update /etc/fstab.
  s->commit();

  destroyStorageInterface(s);

Besides of hard-disks libstorage handles RAID, LVM, NFS, various filesystems and encryption. Swig generated Python bindings are also provided. Libstorage has no dependencies on YaST, neither for building nor runtime. We hope libstorage will also be useful for other projects.

More information is available in the openSUSE Wiki, including a list of useful features people would love to see implemented in the near future.

Comments are as always welcome.

So you got that shiny new Netbook, installed Linux on it and carry
it along everywhere you go. The default enabled Firewall blocks
incoming traffic so you feel safe when connecting to that anonymous
WiFi network at your favorite fastfood restaurant. Unfortunately the
very same Firewall becomes quite annoying at home where it prevents
your system from discovering printers or blocks ssh.

You have the choice of either opening the ports permanently,
exposing your system in hostile networks, or having to use sudo to
enable or disable the Firewall. Well, not anymore with Firewall Zone
Switcher! With that little applet you can now switch the zone of
your network interface to ‘internal’ with only two mouse clicks when
you are at home. In an untrusted Network you just set the zone to
‘external’. And if you need some custom configuration you could set
the zone ‘dmz’ to have some open some ports or create a custom zone.

Firewall Zone Switcher is *not* meant to be some kind of ‘Personal
Firewall’ that confuses the user with all kinds of low level stuff.
It’s neither a Firewall configuration tool. That job is still left
to Admin tools like YaST. Firewall Zone Switcher settings are
temporary and are reset to the system defaults on reboot.

Firewall Zone Switcher consist of a DBus service and a system
tray applet. Both are written in python currently to have proof of
concept program quickly. Packages are available from the openSUSE
build service. You also need to update SuSEfirewall2 from that
repo. Source code repo is available at gitorious.
Keep in mind that the app as well as the patch to SuSEfirewall2 are just proof
of concept ie experimental so there will be bugs. Feedback welcome nevertheless

After more than three years of using Suse 9.3 with Plesk 8.1 on one of my VPS, I decided that it is time to update to OpenSUSE 11.1 with Plesk 9.2.1 control panel. The update process went very well, here are the steps involved:

1. create a full backup of your vps (databases, websites, accounts, emails, ...). I have used "tar" command for that.
2. in plesk 8.1 control panel, do a complete backup (you need plesk backup module to be installed), or if you prefer the command line you can use the following command:

# /usr/local/psa/bin/pleskbackup all

Since version 9.x, the structure of Parallels Plesk Panel backup has been changed. Plesk backup created with Plesk Backup Manager is not just one file but a number of files and directories under backups directory /var/lib/psa/dumps. So, you will need to convert your backup file created in plesk 8.1 to be compatible with plesk 9.x. It's a very simple process, see step 3.

3. convert the created backup file to be compatible with plesk 9.x

# /usr/local/psa/bin/pre9-backup-convert -v convert -d /var/lib/psa/dumps/

where /var/lib/psa/dumps/ is backups directory on the server with Parallels Plesk Panel 9

4. restore the backup files to use them with plesk 9.x. It can be done using the web interface, Home -> Backup Manager -> Server Repository, click the backup name to enter the backup details page and select the required restoration options and click Restore to start the restoration process.

If you would like to use command line to restore your domains, clients, server configuration, ... then you can use the following command:

# /usr/local/psa/bin/pleskrestore --restore /var/lib/psa/dumps/ -level server -verbose -debug

You can restore only clients or domains, for more options see:

# /usr/local/psa/bin/pleskrestore --help

Note: I had a small problem and I found that it is not possible to have a client with the same name as your name in Plesk Admin Profile. Maybe it is stupid, but I had some errors and only after I changed the name in Admin Profile (in Plesk control panel) to be different, I could restore without any problem everything.

I think that's all what I did, from what I remember. If something is missing I am sure you can find a lot of useful stuff using our friend google.

Other useful stuff:

1. Plesk 9.x support as well postfix, so if you want to change from qmail to postfix, try that:

# /usr/local/psa/bin/autoinstaller --select-release-current --install-component postfix

if you are not happy, you can switch back to qmail:

# /usr/local/psa/bin/autoinstaller --select-release-current --install-component qmail.

If you are not sure if you are using qmail or postfix there are many ways to find that, one is to look in Plesk Control Panel on the Services management page {Home -> Services Management} if you have SMTP Server (Postfix) or SMTP Server (QMail)

If you decide you want to switch back, simply, do it, the emails are not lost, don't worry.

2. Replace Horde webmail with AtMail

One of the many new features of Plesk 9, is the option to choose a different webmail client. The default webmail client Horde can be replaced if you are looking for something a bit lighter, AtMail. You need to install from Plesk Control Panel, both webmail clients, and to switch between them:

• Log into Plesk.
• Chose the domain which you want to use another webmail, enter on “Mail Accounts” page
• Click the “Mail Settings” icon
• Switch the “WebMail” to “AtMail (default is Horde)
• Click “OK”

If you decide you want to switch back, simply reverse the procedure, the emails are not lost, don't worry.

That's all.

References:

http://kb.parallels.com/en/5819
http://kb.parallels.com/en/5801
http://kb.parallels.com/en/952
http://kb.parallels.com/en/5969
http://kb.parallels.com/en/5864

I wrote a small article for a internal magazine and few of my friends wanted me to post it to this blog.

This is for people who are new to GDB and still exploring itz features. So if you’ve used GDB for more than few weeks please ignore and skip

GDB – Scripting

A good majority of novice programmers tend to use printf functions to trace function calls and to printout the debug data. This forces you to change the code and compile again and again. To eliminate these superfluous tasks from your day-to-day work, use GDB. The GDB has facilities for scripting and helps in saving plenty of your time.

Tracing Function Calls

If you want to know whether a function is called or not, create a break point and write a simple script.

<code>

#Set the breakpoint

(gdb) b mapi_sync

Breakpoint 1 at 0x7fffd75f36e2: file camel-mapi-folder.c, line 741

#Tell GDB what to do when the breakpoint is reached

(gdb) commands

Type commands for when breakpoint 1 is hit, one per line.

End with a line saying just “end”.

> continue

> end

(gdb)

</code>

continue – Come out of break and continue

end – terminate command list

Run the program now. The GDB prints the function name when the breakpoint is hit and automatically continues running the program.

Breakpoint 1, mapi_sync (folder=0xc9c1a0, expunge=0, ex=0xf3a0c0) at camel-mapi-folder.c:741

741             CamelMapiStore *mapi_store = CAMEL_MAPI_STORE (folder->parent_store);

Using the GDB Scripts for Analyzing the Data

Suppose that you have a singly-linked list that has strings in it. At some point, you might want to know the contents of the list. To do this, use the GDB scripting instead of adding the debug statements in your code.

<code>

#Example for gslist traversal.

define p_gslist_str

set $list = ($arg0)

while ((GSList *)$list->next != 0)

p (char *)(GSList *)$list->data

set $list = (GSList *)$list->next

end

end

document p_gslist_str

p_gslist_str <list>: Dumps the strings in a GSList

end

</code>

Add the above snippet into a file and load it into the GDB as follows:

<code>

(gdb) source /home/jjohnny/scripts/gdb/gslist.gdb

</code>

Now, anywhere you want to take a look in the GSList, simply break and

<code>

(gdb) p_gslist_str server_uid_list

$17 = 0x7fffd81101b0 “7666BC1E000000015870BD1E00000001”

$18 = 0x7fffd810e330 “7666BC1E000000015970BD1E00000001”

$19 = 0x7fffd810cbe0 “7666BC1E000000015C70BD1E00000001”

</code>

Simple scripts thus can save you a lot of time from adding or removing the debugging statements from your code. Now go ahead and create a suite of scripts to aid the library you are writing.

More cool developer tricks later. Have fun !

— End —

Thanks to Radhika for editing the article.

Btw when is Archer branch  (Python scripting) getting into GDB ? I’ve been using it a bit .

Nowadays more and more organisations will use an intercepting proxy to give you access to internet. Last week I had the pleasure to use again such a system. To use is an exaggeration as my opensuse 11.1 box with kde4.3 rc1 connected to the wireless network (network manager) but refused to give me access to the authentication page in the browser.

I did all the decent tests that my brain and time allowed me. Checked the ip, checked gateway and checked dns. They seemed ok.

To make frustration even bigger I was able to connect to th very same network with a kde4.3 beta1.