Linux Installation, Kernel Compilation, and and Kernel Build

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Linux Installation, Kernel Compilation, and and
Kernel Build

• Dr. Ching-Cheng Lee

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Outline

• Linux Distributions
• Linux Installation
• Fedora Core 4 Installation
• Kernel Source Installation
• Linux kernel Source Tree
• Kernel Compilation/Build
• Example New System Call/Kernel

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Linux Distributions

• Debian GNU/Linux
• A distribution produced by Debian Project,
  maintained by volunteers with no commercial
  intentions.
• The name came from the founders DEBra and IAN
  Murdock
• Fedora Linux
• Formally known as Fedora Core
• Sponsored primarily by RedHat with
  significant community participation.
• Produced by Fedora Project and was based on
  the original RedHat Distribution and is made
  entirely of free and open source software

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Linux Distributions - Continued

• Mandriva Linux
• Consumer-oriented distribution available in
  both freely downloadable form and as a boxed
  retail product. Parent company is Mandriva.
• Red Hat Enterprise Linux
• It is the most successful commercial
  distribution of Linux. The company offers
  versions of Red Hat Enterprise Linux (RHEL) for
  servers and workstations. It also sponsors the
  non-commercial distribution Fedora.
• SUSE Linux
• It is a family of Linux distributions
  developed by Novell. It has commercial
  distributions SLED and free-of-charge openSUSE
  (open source community)

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Linux Distributions - Continued

• Ubuntu
• A community developed Linux distribution
  with the slogan Linux for human beings. It is
  one of the most popular Linux distribution for
  laptops and desktop machines. It is based on
  Debian GNU/Linux. The name Ubuntu is an African
  word that can be translated as humanity towards
  others..
• Others
• There are many other distributions such as
  Slackware, CenOS, Damn Small Linux,
  Linspire/Freespire, Linux Mint, PCLinuxOS, etc.

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Linux Installation

• This presentation shows how to install Fedora
  Core 4 on a Windows XP as dual boot system
• Fedora Core 4 CDs
• Installation size 2-3GB
• Installation time 30 minutes 1 hr. (average)
  depending the PC speed.
• Microsoft Windows installed first or existing
• Backup important data in case corruption
• Put the CD (1st) in the drive

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Fedora Core 4 Installation

• Insert the CD
• To install or upgrade in graphical mode, press
  ..
• To install..texttype linux text
  
• boot
• Welcome to Fedora Core
• Upgrade Examine
• Install Fedora Core
• Upgrade an existing installation
• Language Selection ? English
• Keyboard Configuration ? U.S. English

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Fedora Core 4 Installation - Continue

• Installation Type
• Workstation
• Server
• Custom ? select this to gain complete control
  and package selection
• Disk Partitioning Setup
• One of the large obstacles for a new user during
  a Linux installation is partitioning. This
  process is made easier by selecting automatic
• Automatic partition?
• Manually partition with Disk Druid?
• If you used automatic partitioning, you can
  either accept the current partition setting
  (click next) or modify the setup using the manual
  partitioning tool.

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Fedora Core 4 Installation - Continue

• Disk Setup
• Choose where you would like Fedora Core to
  be installed.
• Boot Loader Configuration
• The GRUB boot loader will be installed on
  /dev/xxx
• Change boot loader if you do not want
  to install GRUB
• Network Configuration
• Any network devices you have on the system are
  automatically detected and shown in the Network
  Devices list
• Firewall Configuration
• Enable firewall
• You can use a firewall to allow access to
  specific services on your computer from other
  computer SSH, HTTP, FTP..

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Fedora Core 4 Installation - Continue

• Time Zone Selection
• Set your time zone such as New York,
  Pacific region
• Set Root Password
• Package Group Selection
• Select (check) the package groups that you want
  to install.
• Once a package group has been selected,
  click on Details to view which are default and
  add/remove optional ones from that group.
• About to Install
• Click next to begin installation. The
  Installation log can be found inn
  /root/install.log (To abort this installation,
  reset using Control-Alt-Delete)
• Will see the following messages on the Screen
• Installing Packages .
• Congratulations, the installation is
  complete.reboot your system

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Fedora Core 4 Installation - Continue

• Welcome (message) after reboot
• There are a few more steps to take before
  your system is ready to
• use. The setup agent will guide some basic
  configuration.
• License Agreement Check yes
• Date and Time select and setup
• System User
• Create a system username, non-
  administrative
• Additional CDs
• Insert other CDs for third-party plug-in and
  applications
• Finish Setup
• Screen show login as follows -
• username

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Kernel Source Installation

• Download the kernel source code
• Visit http//kernel.org/ and download the latest
  source code. File name would be
  linux-x.y.z.tar.bz2, where x.y.z is actual
  version number.
• For example file inux-2.6.23.tar.bz2
  represents 2.6.23 kernel version. Use wget
  command to download kernel source code
• cd /tmp wget http//www.kernel.org/pub/linux/k
  ernel/v2.6/linux-x.y.z.tar.bz2
• Note the current kernel version of your Linux can
  be found
• uname -a
• Note Replace x.y.z with actual version number.

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Kernel Source Installation - Continued

• Extract tar (.tar.bz3) file
• Type the following command tar -xjvf
  linux-2.6.23.tar.bz2 -C /usr/src cd /usr/src
• ls
• (you will see a subdirectory linux-2.6.23)
• ln s linux-2.6.23 linux
• Create soft link linux pointing to
  linux-2.6.23 subdirectory
• Your kernel source subdirectory now will
  be /usr/src/linux (Kernel
• source tree)

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Linux Kernel Source Tree

• Kernel Source is under /usr/src
• cd /usr/src
• cd linux (based upon our installation)
• ls
• arch crypto include lib
  net security
• configs Documentation init MAINTAINERS
  README sound
• COPYING drivers ipc Makefile
  REPORTING-BUGS usr
• CREDITS fs kernel mm
  scripts
• ls kernel
• acct.c extable.c Makefile
  profile.c sysctl.c
• audit.c fork.c module.c
  ptrace.c sys_ni.c
• auditsc.c futex.c
  module-verify.c rcupdate.c time.c
• capability.c intermodule.c
  module-verify.h resource.c timer.c
• ..

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Kernel Compilation/Build

• Kernel Source is under /usr/src
• cd /usr/src
• cd linux (based upon our installation)
• For other installation, you need to find the
  subdirectory
• that has kernel source
• make mrproper
• This ensure that the kernel source in
  proper/clean state usually done in the 1st
  time

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Kernel Compilation/Build - Continued

• Configure the .config File
• The .config file contains everything that is
  specific to the kernel you compile. You must
  have a starting .config file. For example, you ca
  use the previous Fedora .config file from the
  fedora kernel.src.rpm.
• If you have another kernel source from another
  RPM or a previously downloaded kernel source, you
  can use that .config instead of Fedora's. Bring
  the .config file up to date to match the new
  kernel. This will prompt for many new options. If
  you know what they are, answer them correctly.
  Otherwise just hit Enter even you see no
  prompts.Usually we suggest that
• make oldconfig (this is usually done
  especially for our project)
• Once done, configure all the necessary options by
  using any of the following This step usually
  can be skipped
• make config or (text based)
• make xconfig (GUI based)

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Kernel Compilation/Build - Continued

• make all
• This will compile all the kernel source code
  using the Makefile and create a compressed kernel
  image.
• This step may take between 30min 2 hours
  depending on the speed of your system.
• make modules
• compiling kernel modules
• make modules_install
• Install kernel modules

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Kernel Compilation/Build - Continued

• make install
• Install the kernel. The following files will
  be installed into the /boot directory
• System.map-2.6.x,
• config-2.6.x..,
• vmlinuz-2.6.x (Newly compiled/compressed
  kernel image)
• Edit Grub
• To set the default to the new kernel, edit
  /boot/grub/grub.conf. Change the line default1
  to default0. This maybe slightly different per
  each computer. This ensure that the new kernel
  will be booted by default.
• reboot
• After reboot, Verify if the new kernel was
  booted.
• uname a (see the version and date
  built)
• If you failed to boot, reboot the old
  kernel (when powering up the machine, you will
  see menu selection of kernels to be booted).
  Otherwise, you must have the original kernel boot
  image save on a bootable floppy.

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Example New System Call/Kernel

• To implement a new system call (i.e. foo), you
  must modify the kernel source, recompile the
  kernel, rebuild the kernel. The user program can
  invoke the new system call with the new kernel
• Modify the system call table
• /usr/src/linux/arch/i386/kernel/entry.S or
• (/usr/src/linux/arch/i386/kernel/syscall_tab
  le.S)
• with new entry
• .login SYMBOL_NAME (sys_foo)

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Example New System Call/kernel Cont.

• System Call Stubs for Users
• /usr/src/linux/include/asm-i386/unitstd.h
• define __NR_keyctl 288 (last entry)
• add the following at the end
• define __NR_foo 289
• Change the folllowing
• define NR_syscall 289 (changed to 290)

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Example New System Call/Kernel Cont.

• System Call Implementation Routine foo()
• Find appropriate subdirectory lets say this
  foo() should be in kernel subdirectory of the
  source code
• cd /usr/src/linux/kernel
• vi sys.c (lets say that we want put
  this routine in sys.c file)
• Follow the same pattern of existing sysall
  implementation
• asmlinkage long sys_foo()
• ..
• printk(KERNEL_EMERG foo syscall entered\n)

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Example New System Call/Kernel Cont.

• Go to /usr/src/linux directory
• Recompile the kernel source and build new kernel
  as in previous described steps.
• Reboot the new kernel
• Verify if the system has the newly build kernel
• uname -a
• Write a test program to test this new system call