Windows equivalent to ldd

I love the ldd tool in Linux and needed this badly on Windows. Windows equivalent can be done using obj-dump

objdump.exe -p ref_read.exe

This command gives a long list of all the dlls and the functions I use in my application, ref_read.exe. So a shorter list can be extracted using grep

objdump.exe -p ref_read.exe | grep .dll


How to create bare minimum Debian Wheezy rootfs from scratch

This is a good read for creating rootfs for debian versions. To login as root without password remove * in this line root:*:16393:0:99999:7::: of /etc/shadow file.



In this post we will explain how you can create your own Debian rootfs with pre-installed packages of your choice, which to allow tiny Linux images to be created.

All steps below should work on any Debian host (Debian/Ubuntu etc) and are verified with Ubuntu 12.04LTS.

First of all you need to install the support packages on your pc

sudo apt-get install qemu-user-static debootstrap binfmt-support

Next you need to choose the version of Debian in this case we are building a wheezy image.


Now we will build first stage of Debian rootfs :

mkdir $targetdirsudo debootstrap --arch=armhf --foreign $distro $targetdir

Next copy the qemu-arm-static binary into the right place for the binfmt packages to find it and copy in resolv.conf from the host.

sudo cp /usr/bin/qemu-arm-static $targetdir/usr/bin/sudo cp /etc/resolv.conf $targetdir/etc

If everything is right we now have a minimal Debian Rootfs

sudo chroot $targetdir

Inside the…

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How to send patches with git-send-email


The prerequisites for this tutorial is that you have already made some changes to your local kernel tree and that these changes have been committed.
In this tutorial, are described the steps to follow in order to create and send a patch series using git-send-email.

Initially, you need to determine which of your commits want to be sent, so do:

$ git log --pretty=oneline --abbrev-commit

The output, in my case, looks like:

db868ad xhci: remove conversion from generic to pci device in xhci_mem.c
c010f0c xhci: remove unnecessary check in xhci_free_stream_info()
a166493 xhci: fix SCT_FOR_CTX(p) macro
56e4cd3 xhci: replace USB_MAXINTERFACES with config->desc.bNumInterface

Lets assume that I want to send the last 3 commits i.e db868ad, c010f0c and a166493. The first thing I need to do is to create patches for these commits and store them in a local directory e.g. ~/patches/

Patches that can be sent using git-send-email should have…

View original post 998 more words

Add hardisk to Oracle VirtualBox

I keep forgetting these steps so I decided to document them. Steps to add a extra hard disk space in Oracel virtual box. This is for Ubuntu

1. Add a hardisk using the option from virtual machine settings as shown


2. Start the virtual machine. Once the machine is up run the command to get the mname of the driver

sudo fdisk -l

In my case it is /dev/sdc

3. Partition the disk using the command

sudo fdisk /dev/sdc

Then use the command “n” to add a partition and “p” for primary partition. Use the default values (if you have no idea of what they are) and finally use “w” to write the partition table to the disk.

"The partition table has been altered!" 

message indicates partition is successful

4. Format the disk into the filesystem of your choice. I am using ext4 so the coomand is

sudo mkfs -t ext4 /dev/sdc1

5. Creating a mount point. I mount the disk at the location /media/etc_drive_2/ so I create a drive using the command

sudo mkdir /media/etc_drive_2/

6. For auto mount at every startup edit fstab

gksu gedit /etc/fstab

And add the following line

/dev/sdc1    /media/etc_drive_2  ext4    defaults     0        2

The name of the driver and folder name changes based on your system

7. Access permission. I have set the access permission for my login. To do so first mount the drive using the command

sudo mount /dev/sdc1 /media/etc_drive_2

And set access permission using

sudo chown -R USERNAME:USERNAME /media/etc_drive_2

replace USERNAME with correct username

For detailed reading and much more fun visit

An easy kernel development environment

This article which sounds like anti-oracle virtual box, but it wasn’t and highlighted the use of virtual box made me write this blog.

I have been a big fan of Oracle virtual box and indeed it’s the best Type2 hypervisor (based on features for x86) I have used. I would say qemu as the lightest and the fastest. When I started poking around on Linux kernel running over virtual box, my modules crashed and caused file-system corruptions. This led me to use a desktop machine as a Linux test machine. But I could not carry my test machine with me. And so, I have changed my environment to two virtual machines (test and development) using virtual box.

I will describe here how to Setup two virtual machines for Linux development environment

Please refer these links which describe how to :

  1. Build and test a module using the environment refer here.
  2. Change the kernel of test machine refer here
  3. Removing the kernel of test machine refer here

Overview of the setup:

  • Host OS is windows
  • Virtual box from Oracle
  • Ubuntu as the test and development Linux distribution


1. Downloads and software packages:

  • Download Oracle Virtual Box  and don’t forget the corresponding extension pack.
  • Download the Ubuntu ISO. I use Ubuntu 12.10. You can use Ubuntu 12.04 as it is LTS.

2. Virtual machines: Create two virtual machines,

  • Development machine with at least 20GB hard disk
  • Test machine with 4.5GB hard disk.

Refer the virtual box user guide if any doubts.

3. New network interface: Create a new host only adapter in the virtual box from Oracle VM Virtual Box Manager > File > Preferences > Network.


Create new adapter with the credentials as shown.


So the network adapter appears as shown


4. Tuning the test machine: Boot the test machine and strip it to bare minimum by removing the unnecessary software like games, Firefox etc. Even strip its GUI and make it text only using the grub as described here.

5. Setting up the network: With both the virtual machines stopped configure the network interface as shown.



Leave the first network adapter unaltered in the development machine. This interface will be used for downloading additional softwares.
Now start both the machines and get the IP of both machines using “ifconfig”. In my case development machine IP is 192.10.100 and test machine IP is 192.10.101. Ping both the machines from each other and verify the network connection.

6. First login: To login to the test machine using SSH install openSSH-client in your development machine using the command at a terminal

sudo apt-get install openssh-client

Now type the command at a terminal

ssh test@

I have used test as it is my user name on test machine. You will get a warning for the RSA when you login the first time

The authenticity of host '' can't be established.
RSA key fingerprint is b1:2d:33:67:ce:35:4d:5f:f3:a8:cd:c0:c4:48:86:12.
Are you sure you want to continue connecting (yes/no)?

Type yes

7. Test: You can test the setup by shutting down the test machine using the command after logging on to the machine on ssh

$ sudo poweroff

The Linux development environment is configured.

Please feel free to send me queries or improvements for this writeup. If you find this useful or useless please post your reply