Difference between these two methods of downloading linux source code

Question

System info:

root@zaidi:/home/uzair# uname -a
Linux zaidi 3.11.0-26-generic #45~precise1-Ubuntu SMP Tue Jul 15 04:04:35 UTC 2014 i686 i686 i386 GNU/Linux

I am trying to write a simple device driver. For that I need to download the source code of the kernel I am running (right?)

I found following two methods:

apt-get install linux-source-$(uname -r)


apt-get source linux-image-$(uname -r)

What is the difference between these two commands? Which one is actually required for building the driver. I have a make file like this:

# Makefile – makefile of our first driver
# if KERNELRELEASE is defined, we've been invoked from the
# kernel build system and can use its language.
ifneq (${KERNELRELEASE},)
    obj-m := ofd.o
# Otherwise we were called directly from the command line.
# Invoke the kernel build system.
else
    KERNEL_SOURCE := /usr/src/linux
    PWD := $(shell pwd)
default:
    ${MAKE} -C ${KERNEL_SOURCE} SUBDIRS=${PWD} modules
clean:
    ${MAKE} -C ${KERNEL_SOURCE} SUBDIRS=${PWD} clean
endif

I would like to have the source code in /usr/src/linux

Answer 1

Difference between installation process by apt-get install & by apt-get source:

1. sudo apt-get install <package>installs packages with their dependencies from repositories and cached files are found at /var/cache/apt/archives in .deb extension.
2. sudo apt-get source <package> will download source files in current directory.

Now take look at how to build & install package from downloaded source files (from repository):

• First install build-dependencies by command : sudo apt-get build-dep <package>
• Then download source package by command : sudo apt-get source <package>
• Then navigate to directory containing source by cd and use dpkg-buildpackage -uc -us -b to get binaries, dpkg-buildpackage -uc -us -S for a source package without using sudo.
• It get/build .deb files which can be installed by dpkg -i <file-name>.deb

---

But if <package> is directly available to install from repositories then it is recommended to install packages by following command

sudo apt-get install <package>

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For compiling package from source code visit :community help

Answer 2

You should only need the appropriate linux-headers package:

apt-cache show linux-source-3.13.0
Package: linux-source-3.13.0
...
Description-en: Linux kernel source for version 3.13.0 with Ubuntu patches
This package provides the source code for the Linux kernel version
3.13.0.
 .
This package is mainly meant for other packages to use, in order to build
custom flavours.
.
If you wish to use this package to create a custom Linux kernel, then it
is suggested that you investigate the package kernel-package, which has
been designed to ease the task of creating kernel image packages.
.
If you are simply trying to build third-party modules for your kernel,
you do not want this package. Install the appropriate linux-headers
package instead.

Do:

sudo apt-get install linux-headers-$(uname -r)