cis 191 - lesson 13 linux kernel. architecture dependent kernel code kernel space process management...

CIS 191 - Lesson 13

LinuxKernel

Architecture DependentKernel Code

KernelSpace

ProcessManagement

MemoryManagement

Network Stack

Virtual File System

UserSpace

Device Drivers

Kernel1

Hardware

System Call Interface

Users

Commands & Utilities

Shell

X / Desktops

(multi-user)

GNU C Library (glibc)

Programs (multi-tasking)

Add-ons

1See “Anatomy of the Linux kernel” by M. Tim Jones at http://www-128.ibm.com/developerworks/linux/library/l-linux-kernel/

GNU/Linux Operating System Architecture

Richard Stallman started the GNU project in 1983 to create a free UNIX-like OS. He Founded the Free Software Foundation in 1985. In 1989 he wrote the first version of the GNU General Public License

Linus Torvalds, as a student, initially conceived and assembled the Linux kernel in 1991. The kernel was later re-licensed under the GNU General Public License in 1992.

CIS 191 - Lesson 13

http://www-128.ibm.com/developerworks/linux/library/l-linux-kernel/









http://en.wikipedia.org/wiki/Image:Tux.svg

http://en.wikipedia.org/wiki/Image:Heckert_GNU_white.svg

http://en.wikipedia.org/wiki/Image:Linus_Torvalds.jpeg

http://en.wikipedia.org/wiki/Image:Portrait_-_Denmark_DTU_2007-3-31.jpg

The Linux Kernel (in /boot)Major Subsystems:

• System Call Interface • mechanism for user space programs to request kernel services.

• Process Management • handles fork, exec, exit, kill, signals, CPU scheduling, etc.

• Memory Management • allocation, usage tracking, paging, etc.

• Virtual File System• open, close, read, write, caching, etc.

• Architecture Dependent Kernel Code• Drivers (in /lib)

Design• Linux kernel is “monolithic”, not a “microkernel”• Dynamic – can load and unload modules on the fly• Overtime has become efficient, stable and portable

CIS 191 – Lesson 13

http://en.wikipedia.org/wiki/Image:Tux.svg

CIS 191 - Lesson 13

The Linux KernelBuilding a New Kernel

Obtain and verify kernel source tarball Extract source code Install development tools Configure the kernel options

make config or make menuconfig or make xconfig or make gconfig or make oldconfig

make clean make bzImage make modules make modules_install make install

Steps for building a new kernel

CIS 191 - Lesson 13




make clean make bzImage make modules make modules_install make install must be done as

root user

CIS 191 - Lesson 13





cleans up object files created from previous compiles

CIS 191 - Lesson 13





Compile the kernel

CIS 191 - Lesson 13

The Linux KernelKernel Background

Obtain and kernel source code

‒ http://www.kernel.org

‒ Download either: *.tar.bz2 or *.tar.gz files

bzip2 or gzip tarballs

CIS 191 - Lesson 13





Compile the loadable kernel modules

CIS 191 - Lesson 13





Install the loadable kernel modules in /lib

CIS 191 - Lesson 13




make clean make bzImage make modules make modules_install make install Copy files to /boot

CIS 191 - Lesson 13

http://kernel.org/

Click here

CIS 191 - Lesson 13

http://www.kernel.org/pub/

Click here

CIS 191 - Lesson 13

http://www.kernel.org/pub/linux/

Click here

CIS 191 - Lesson 13

http://www.kernel.org/pub/linux/kernel/

Click here

CIS 191 - Lesson 13

Change logs show fixed bugs and any enhancements

http://www.kernel.org/pub/linux/kernel/v2.6/

CIS 191 - Lesson 13

Completekernels


CIS 191 - Lesson 13


Patches

CIS 191 - Lesson 13

http://kernel.org/

The latest (as of the date making this slide)

http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.27.8

CIS 191 - Lesson 13

http://kernel.org/

Create a tarballs directory in /depot

Obtain kernel tarballs and place in this directory

CIS 191 - Lesson 13

http://kernel.org/

Many ways to get the tarballs• wget command• Run level 5, run firefox, and download• Download on another system and use Filezilla to

transfer to Benji VM

CIS 191 - Lesson 13

http://kernel.org/

Using wget to get files from kernel.org

CIS 191 - Lesson 13

Getting kernel files to VM

Download files to windows and transfer to VM with FileZilla

CIS 191 - Lesson 13

http://kernel.org/

[root@benji tarballs]# ls -ltotal 49408-rw-r--r-- 1 root root 50384960 Dec 6 13:59 linux-2.6.27.8.tar.bz2-rw-r--r-- 1 root root 248 Dec 6 13:58 linux-2.6.27.8.tar.bz2.sign-rw-r--r-- 1 root root 125174 Dec 5 14:16 patch-2.6.27.8.bz2[root@benji tarballs]#

Latest kernel source, patch and signature file

CIS 191 - Lesson 13

http://kernel.org/

Verify the downloaded source code• Obtain the public key from

http://www.kernel.org/signature.html• And copy it into a new file kernel.pubkey• Import the key

gpg --import kernel.pubkey• View the new key

gpg --list-keys• Verify

gpg --verify linux-2.6.27.8.tar.bz2.sign linux-2.6.27.8.tar.bz2

Linux Kernel Archive files are signed using OpenPGP. This signature can be used to prove downloaded files originated at the Linux Kernel Archives.

CIS 191 - Lesson 13

http://kernel.org/

Lets check we didn't get malicious code

CIS 191 - Lesson 13

http://kernel.org/

Public and private keys are used to verify source code is authentic

CIS 191 - Lesson 13

http://kernel.org/

Copy the public key to the clipboard

CIS 191 - Lesson 13

http://kernel.org/

[root@benji tarballs]# vi kernel.pubkey

Edit a new file to place the public key

CIS 191 - Lesson 13

http://kernel.org/

Go to Insert mode and paste the key with a right click

CIS 191 - Lesson 13

http://kernel.org/

Scroll back to the top and make sure you got the whole public keythen save it.

CIS 191 - Lesson 13

http://kernel.org/

Import the public key to your key collection

CIS 191 - Lesson 13

http://kernel.org/

List your set of keys and verify it was added

CIS 191 - Lesson 13

http://kernel.org/

You will get a warning unless you have built a trust path to the Linux Kernel Archives Verification Key

The first section shows the verification

CIS 191 - Lesson 13





CIS 191 - Lesson 13

Extract source code

Extract the source code from the archivetar -xvjf linux-2.6.27.8.tar.bz2

Use j option for bzip2 compression

CIS 191 - Lesson 13

Extracting the kernel source code

Extract source code

CIS 191 - Lesson 13

Note the new linux-2.6.27.8 directory

cd into it

Extract source code

CIS 191 - Lesson 13

Building the kernel

Listing of the new linux-2.6.27.8 directory

CIS 191 - Lesson 13

Building the kernel

Peek at some C code written by Linus

CIS 191 - Lesson 13




make dep make clean make bzImage make modules make modules_install make install

CIS 191 - Lesson 13

http://kernel.org/

Install development toolsyum install gccyum install ncurses-devel

GNU C compiler and curses (line drawing characters) library

CIS 191 - Lesson 13

Install build tools

Install the C compiler

CIS 191 - Lesson 13

--> Processing Dependency: libgomp.so.1 for package: gcc--> Processing Dependency: libgcc >= 4.1.2-42.el5 for package: gcc--> Restarting Dependency Resolution with new changes.--> Populating transaction set with selected packages. Please wait.---> Downloading header for cpp to pack into transaction set.cpp-4.1.2-42.el5.i386.rpm 100% |=========================| 64 kB 00:00---> Package cpp.i386 0:4.1.2-42.el5 set to be updated---> Downloading header for libgcc to pack into transaction set.libgcc-4.1.2-42.el5.i386. 100% |=========================| 60 kB 00:00---> Package libgcc.i386 0:4.1.2-42.el5 set to be updated---> Downloading header for glibc-devel to pack into transaction set.glibc-devel-2.5-24.el5_2. 100% |=========================| 111 kB 00:02---> Package glibc-devel.i386 0:2.5-24.el5_2.2 set to be updated---> Downloading header for libgomp to pack into transaction set.libgomp-4.1.2-42.el5.i386 100% |=========================| 60 kB 00:00---> Package libgomp.i386 0:4.1.2-42.el5 set to be updated--> Running transaction check--> Processing Dependency: glibc-headers for package: glibc-devel--> Processing Dependency: glibc = 2.5-24.el5_2.2 for package: glibc-devel--> Processing Dependency: glibc-headers = 2.5-24.el5_2.2 for package: glibc-develRestarting Dependency Resolution with new changes.--> Populating transaction set with selected packages. Please wait.

Install the C compiler (continued)

Install build tools

CIS 191 - Lesson 13

--> Populating transaction set with selected packages. Please wait.---> Downloading header for glibc-headers to pack into transaction set.glibc-headers-2.5-24.el5_ 100% |=========================| 144 kB 00:01---> Package glibc-headers.i386 0:2.5-24.el5_2.2 set to be updated---> Downloading header for glibc to pack into transaction set.glibc-2.5-24.el5_2.2.i686 100% |=========================| 146 kB 00:01---> Package glibc.i686 0:2.5-24.el5_2.2 set to be updated--> Running transaction check--> Processing Dependency: glibc-common = 2.5-24.el5_2.2 for package: glibc--> Restarting Dependency Resolution with new changes.--> Populating transaction set with selected packages. Please wait.---> Downloading header for glibc-common to pack into transaction set.glibc-common-2.5-24.el5_2 100% |=========================| 725 kB 00:09---> Package glibc-common.i386 0:2.5-24.el5_2.2 set to be updated--> Running transaction check

Dependencies Resolved


Install build tools

CIS 191 - Lesson 13

Building the kernel

============================================================================= Package Arch Version Repository Size=============================================================================Installing: gcc i386 4.1.2-42.el5 base 5.2 MInstalling for dependencies: glibc-devel i386 2.5-24.el5_2.2 updates 2.0 M glibc-headers i386 2.5-24.el5_2.2 updates 611 k libgomp i386 4.1.2-42.el5 base 82 kUpdating for dependencies: cpp i386 4.1.2-42.el5 base 2.7 M glibc i686 2.5-24.el5_2.2 updates 5.2 M glibc-common i386 2.5-24.el5_2.2 updates 16 M libgcc i386 4.1.2-42.el5 base 93 k

Transaction Summary=============================================================================Install 4 Package(s)Update 4 Package(s)Remove 0 Package(s)

Total download size: 32 MIs this ok [y/N]: y


CIS 191 - Lesson 13

Building the kernelIs this ok [y/N]: yDownloading Packages:(1/8): libgcc-4.1.2-42.el 100% |=========================| 93 kB 00:01(2/8): glibc-devel-2.5-24 100% |=========================| 2.0 MB 00:20(3/8): glibc-headers-2.5- 100% |=========================| 611 kB 00:07(4/8): gcc-4.1.2-42.el5.i 100% |=========================| 5.2 MB 00:51(5/8): cpp-4.1.2-42.el5.i 100% |=========================| 2.7 MB 00:21(6/8): glibc-2.5-24.el5_2 100% |=========================| 5.2 MB 01:07(7/8): glibc-common-2.5-2 100% |=========================| 16 MB 04:40(8/8): libgomp-4.1.2-42.e 100% |=========================| 82 kB 00:01Running Transaction TestFinished Transaction TestTransaction Test Succeeded


CIS 191 - Lesson 13

Building the kernelRunning Transaction Updating : libgcc ####################### [ 1/12] Updating : glibc-common ####################### [ 2/12] Updating : glibc ####################### [ 3/12] Installing: glibc-headers ####################### [ 4/12] Installing: glibc-devel ####################### [ 5/12] Updating : cpp ####################### [ 6/12] Installing: libgomp ####################### [ 7/12] Installing: gcc ####################### [ 8/12] Cleanup : libgcc ####################### [ 9/12] Cleanup : cpp ####################### [10/12] Cleanup : glibc ####################### [11/12] Cleanup : glibc-common ####################### [12/12]

Installed: gcc.i386 0:4.1.2-42.el5Dependency Installed: glibc-devel.i386 0:2.5-24.el5_2.2 glibc-headers.i386 0:2.5-24.el5_2.2 libgomp.i386 0:4.1.2-42.el5Dependency Updated: cpp.i386 0:4.1.2-42.el5 glibc.i686 0:2.5-24.el5_2.2 glibc-common.i386 0:2.5-24.el5_2.2 libgcc.i386 0:4.1.2-42.el5Complete![root@benji tarballs]#


CIS 191 - Lesson 13

Building the kernel

Install ncurses-devel for make menu-config tool

CIS 191 - Lesson 13

Building the kernel


Total download size: 1.6 MIs this ok [y/N]: yDownloading Packages:(1/1): ncurses-devel-5.5- 100% |=========================| 1.6 MB 00:11Running Transaction TestFinished Transaction TestTransaction Test SucceededRunning Transaction Installing: ncurses-devel ######################### [1/1]

Installed: ncurses-devel.i386 0:5.5-24.20060715Complete![root@benji linux-2.6.27.8]#

install ncurses-devel (continued)

CIS 191 - Lesson 13




make dep make clean make bzImage make modules make modules_install make install

CIS 191 - Lesson 13

The Linux KernelKernel Configuration Option Categories

• Code maturity level options • Loadable module support • Processor type and features • General setup • Memory Technology Devices • Plug n Play configuration • Block devices • Networking options • Telephony support • ATA/IDE/MFM/RLL support • SCSI support • I2O device support • Network device support

• Amateur radio support • IrDA (infrared) support • ISDN subsystem • Old CD-ROM drivers (not SCSI,

not IDE) • Character devices • Multimedia devices • File systems • Console drivers • Sound • USB support • Kernel hacking

There are bazillions of options for building the kernel

CIS 191 - Lesson 13

The Linux KernelKernel Configuration Options

make config

or make menuconfig or make xconfig

or make gconfig

or make oldconfig

CIS 191 - Lesson 13

make config (and holding down the enter key)

Configuring the kernel build

CIS 191 - Lesson 13

Configuring the kernel buildmake config method

[root@benji linux-2.6.27.8]# make config HOSTCC scripts/basic/fixdep HOSTCC scripts/basic/docproc HOSTCC scripts/kconfig/conf.o HOSTCC scripts/kconfig/kxgettext.o SHIPPED scripts/kconfig/zconf.tab.c SHIPPED scripts/kconfig/lex.zconf.c SHIPPED scripts/kconfig/zconf.hash.c HOSTCC scripts/kconfig/zconf.tab.o HOSTLD scripts/kconfig/confscripts/kconfig/conf arch/x86/Kconfig## using defaults found in /boot/config-2.6.18-8.el5#/boot/config-2.6.18-8.el5:1280:warning: symbol value 'm' invalid for FIXED_PHY/boot/config-2.6.18-8.el5:1532:warning: symbol value 'm' invalid for ISDN/boot/config-2.6.18-8.el5:2612:warning: symbol value 'm' invalid for RTC_INTF_SYSFS/boot/config-2.6.18-8.el5:2613:warning: symbol value 'm' invalid for

CIS 191 - Lesson 13

make config (continued)


http://simms-teach.com/docs/cis191/cis191esson13-make-config.pdf

(and holding down the Enter key to take all the defaults)

CIS 191 - Lesson 13

After running make config

[root@benji linux-2.6.27.8]# ls -latotal 616drwxrwxr-x 22 root root 4096 Dec 6 18:06 .drwxr-xr-x 3 root root 4096 Dec 6 18:01 ..drwxrwxr-x 24 root root 4096 Dec 5 12:03 archdrwxrwxr-x 2 root root 4096 Dec 5 12:03 block-rw-r--r-- 1 root root 72417 Dec 6 18:06 .config-rw-rw-r-- 1 root root 18693 Dec 5 12:03 COPYING-rw-rw-r-- 1 root root 92899 Dec 5 12:03 CREDITSdrwxrwxr-x 3 root root 4096 Dec 5 12:03 cryptodrwxrwxr-x 78 root root 12288 Dec 5 12:03 Documentationdrwxrwxr-x 80 root root 4096 Dec 5 12:03 driversdrwxrwxr-x 17 root root 4096 Dec 5 12:03 firmwaredrwxrwxr-x 64 root root 4096 Dec 5 12:03 fs-rw-rw-r-- 1 root root 867 Dec 5 12:03 .gitignoredrwxrwxr-x 31 root root 4096 Dec 6 18:05 includedrwxrwxr-x 2 root root 4096 Dec 5 12:03 initdrwxrwxr-x 2 root root 4096 Dec 5 12:03 ipc


http://simms-teach.com/docs/cis191/cis191esson13-dot-config.pdf

CIS 191 - Lesson 13

-rw-rw-r-- 1 root root 2430 Dec 5 12:03 Kbuilddrwxrwxr-x 6 root root 4096 Dec 5 12:03 kerneldrwxrwxr-x 6 root root 4096 Dec 5 12:03 libdrwxrwxr-x 6 root root 4096 Dec 5 12:03 lib-rw-rw-r-- 1 root root 3799 Dec 5 12:03 .mailmap-rw-rw-r-- 1 root root 101926 Dec 5 12:03 MAINTAINERS-rw-rw-r-- 1 root root 56768 Dec 5 12:03 Makefiledrwxrwxr-x 2 root root 4096 Dec 5 12:03 mmdrwxrwxr-x 43 root root 4096 Dec 5 12:03 net-rw-rw-r-- 1 root root 16930 Dec 5 12:03 README-rw-rw-r-- 1 root root 3172 Dec 5 12:03 REPORTING-BUGSdrwxrwxr-x 6 root root 4096 Dec 5 12:03 samplesdrwxrwxr-x 9 root root 4096 Dec 5 12:03 scriptsdrwxrwxr-x 5 root root 4096 Dec 5 12:03 securitydrwxrwxr-x 20 root root 4096 Dec 5 12:03 sounddrwxrwxr-x 2 root root 4096 Dec 5 12:03 usrdrwxrwxr-x 3 root root 4096 Dec 5 12:03 virt[root@benji linux-2.6.27.8]#

After running make config


skip this for now

CIS 191 - Lesson 13

make menuconfig


needs ncurses package for line drawing set

CIS 191 - Lesson 13

make menuconfig


CIS 191 - Lesson 13

make oldconfig

and hold down the enter key


CIS 191 - Lesson 13

Note make config and make oldconfig yielded the same configuration file


CIS 191 - Lesson 13

The hidden .config file

[root@benji linux-2.6.27.8]# ls -a. .config.old drivers init .mailmap README sound.. COPYING firmware ipc MAINTAINERS REPORTING-BUGS usrarch CREDITS fs Kbuild Makefile samples virtblock crypto .gitignore kernel mm scripts.config Documentation include lib net security[root@benji linux-2.6.27.8]#


http://simms-teach.com/docs/cis191/cis191esson13-dot-config.pdf

CIS 191 - Lesson 13

.config file


http://simms-teach.com/docs/cis191/cis191esson13-make-config.pdf

CIS 191 - Lesson 13




make dep (not required for v2.6 and higher) make clean make bzImage make modules make modules_install make install

We are building a v2.6 kernel

CIS 191 - Lesson 13

Building the kernel

Clean up miscellaneous object files

CIS 191 - Lesson 13





CIS 191 - Lesson 13

Building the kernel

Start compiling

11:42 pm – 11:52 pm

http://simms-teach.com/docs/cis191/cis191esson13-make-bzImage.pdf

CIS 191 - Lesson 13





CIS 191 - Lesson 13

Building the kernel

Start compiling modules

11:59 -12:20

http://simms-teach.com/docs/cis191/cis191esson13-make-modules.pdf

CIS 191 - Lesson 13

Building the kernel

Post compile

[root@benji linux-2.6.27.8]# ls -aF./ ipc/ scripts/ .tmp_vmlinux1*../ Kbuild security/ ..tmp_vmlinux1.cmdarch/ kernel/ sound/ .tmp_vmlinux2*block/ lib/ System.map ..tmp_vmlinux2.cmd.config .mailmap .tmp_kallsyms1.o .tmp_vmlinux3*COPYING MAINTAINERS ..tmp_kallsyms1.o.cmd ..tmp_vmlinux3.cmdCREDITS Makefile .tmp_kallsyms1.S usr/crypto/ .missing-syscalls.d .tmp_kallsyms2.o .versionDocumentation/ mm/ ..tmp_kallsyms2.o.cmd virt/drivers/ modules.order .tmp_kallsyms2.S vmlinux*firmware/ Module.symvers .tmp_kallsyms3.o .vmlinux.cmdfs/ net/ ..tmp_kallsyms3.o.cmd vmlinux.o.gitignore README .tmp_kallsyms3.S .vmlinux.o.cmdinclude/ REPORTING-BUGS .tmp_System.mapinit/ samples/ .tmp_versions/[root@benji linux-2.6.27.8]#

CIS 191 - Lesson 13

Building the kernel

Post compile

[root@benji linux-2.6.27.8]# ls -ltotal 153100drwxrwxr-x 25 root root 4096 Dec 6 18:25 archdrwxrwxr-x 2 root root 4096 Dec 6 18:37 block-rw-rw-r-- 1 root root 18693 Dec 5 12:03 COPYING-rw-rw-r-- 1 root root 92899 Dec 5 12:03 CREDITSdrwxrwxr-x 3 root root 12288 Dec 6 18:53 cryptodrwxrwxr-x 78 root root 12288 Dec 5 12:03 Documentationdrwxrwxr-x 80 root root 4096 Dec 6 18:46 driversdrwxrwxr-x 17 root root 4096 Dec 6 18:56 firmwaredrwxrwxr-x 64 root root 12288 Dec 6 18:37 fsdrwxrwxr-x 31 root root 4096 Dec 6 18:16 includedrwxrwxr-x 2 root root 4096 Dec 6 18:34 initdrwxrwxr-x 2 root root 4096 Dec 6 18:37 ipc-rw-rw-r-- 1 root root 2430 Dec 5 12:03 Kbuilddrwxrwxr-x 6 root root 12288 Dec 6 18:34 kerneldrwxrwxr-x 6 root root 12288 Dec 6 18:55 lib-rw-rw-r-- 1 root root 101926 Dec 5 12:03 MAINTAINERS-rw-rw-r-- 1 root root 56768 Dec 5 12:03 Makefiledrwxrwxr-x 2 root root 4096 Dec 6 18:34 mm

CIS 191 - Lesson 13

Building the kernel

Post compile

drwxrwxr-x 2 root root 4096 Dec 6 18:34 mm-rw-r--r-- 1 root root 33750 Dec 6 18:52 modules.order-rw-r--r-- 1 root root 337836 Dec 6 18:52 Module.symversdrwxrwxr-x 43 root root 4096 Dec 6 18:52 net-rw-rw-r-- 1 root root 16930 Dec 5 12:03 README-rw-rw-r-- 1 root root 3172 Dec 5 12:03 REPORTING-BUGSdrwxrwxr-x 6 root root 4096 Dec 5 12:03 samplesdrwxrwxr-x 9 root root 4096 Dec 6 18:34 scriptsdrwxrwxr-x 5 root root 4096 Dec 6 18:37 securitydrwxrwxr-x 20 root root 4096 Dec 6 18:56 sound-rw-r--r-- 1 root root 1076204 Dec 6 18:25 System.mapdrwxrwxr-x 2 root root 4096 Dec 6 18:34 usrdrwxrwxr-x 3 root root 4096 Dec 5 12:03 virt-rwxr-xr-x 1 root root 69534188 Dec 6 18:25 vmlinux-rw-r--r-- 1 root root 85037854 Dec 6 18:24 vmlinux.o[root@benji linux-2.6.27.8]#

vmlinux is the uncompressed kernel

CIS 191 - Lesson 13

Building the kernel

text segment: the instructions that will be executed by the CPU

data segment: initialized program variables

bss: uninitialized or zero-initialized data segment

CIS 191 - Lesson 13

Building the kernel

Post compile

bxImage is the compressed version of the new kernel

CIS 191 - Lesson 13





CIS 191 - Lesson 13

Building the kernel

Check disk space before make modules_install

The kernel modules will be placed in /lib using up more of /dev/sda1

CIS 191 - Lesson 13

Building the kernel

make modules_install

http://simms-teach.com/docs/cis191/cis191esson13-make-modules_install.pdf

CIS 191 - Lesson 13

Building the kernel

After make modules_install

CIS 191 - Lesson 13

Building the kernelAfter make modules_install

Increased / partition usage from 69% to 77%

CIS 191 - Lesson 13





CIS 191 - Lesson 13

Building the kernelBefore make install

CIS 191 - Lesson 13

Building the kernelBefore make install

[root@benji linux-2.6.27.8]# ls /bootconfig-2.6.18-8.el5 symvers-2.6.18-8.el5.gzconfig-2.6.18-92.1.13.el5 symvers-2.6.18-92.1.13.el5.gzgrub System.map-2.6.18-8.el5initrd-2.6.18-8.el5.img System.map-2.6.18-92.1.13.el5initrd-2.6.18-92.1.13.el5.img vmlinuz-2.6.18-8.el5message vmlinuz-2.6.18-92.1.13.el5[root@benji linux-2.6.27.8]#

Note that we do not see 2.6.27.8 files

CIS 191 - Lesson 13

Building the kernelmake install

CIS 191 - Lesson 13

Building the kernelAfter make install

[root@benji linux-2.6.27.8]# cat /boot/grub/grub.conf# grub.conf generated by anaconda## Note that you do not have to rerun grub after making changes to this file# NOTICE: You do not have a /boot partition. This means that# all kernel and initrd paths are relative to /, eg.# root (hd0,0)# kernel /boot/vmlinuz-version ro root=/dev/sda1# initrd /boot/initrd-version.img

#boot=/dev/sda1default=2timeout=60splashimage=(hd0,0)/boot/grub/splash.xpm.gz#hiddenmenutitle CentOS (2.6.27.8) root (hd0,0) kernel /boot/vmlinuz-2.6.27.8 ro root=LABEL=/1 rhgb quiet initrd /boot/initrd-2.6.27.8.imgtitle CentOS (2.6.18-92.1.13.el5) root (hd0,0) kernel /boot/vmlinuz-2.6.18-92.1.13.el5 ro root=LABEL=/1 rhgb quiet initrd /boot/initrd-2.6.18-92.1.13.el5.imgtitle CentOS (2.6.18-8.el5) root (hd0,0) kernel /boot/vmlinuz-2.6.18-8.el5 ro root=LABEL=/1 rhgb quiet initrd /boot/initrd-2.6.18-8.el5.imgtitle My Distro root (hd0,0) kernel /boot/vmlinuz-2.6.18-8.el5 ro root=/dev/sda6 init=/bin/bash initrd /boot/initrd-2.6.18-8.el5.img[root@benji linux-2.6.27.8]#

CIS 191 - Lesson 13

Building the kernelAfter make install the kernel is copied to the /boot directory

copy of bzImage (compressed kernel)

Initial ram disk

kernel symbol table

bzImage = vmlinuz

CIS 191 - Lesson 13





CIS 191 - Lesson 13

Building the kernelAfter make install

CIS 191 - Lesson 13

Patches

CIS 191 - Lesson 13

The Linux KernelPatches

• Applying a Kernel Patch

‒ copy the patch file to /depot

‒ uncompress it with bunzip2 or gunzip as

appropriate

‒ cd to your kernel build directory (named using

the version number of the full kernel built

previously)

‒ patch -p1 < ../patch-2.6.27.n

‒ Apply patches in order

‒ Rebuild everything again

CIS 191 - Lesson 13

Kernel RPM Updates

CIS 191 - Lesson 13

Updating a kernel RPMBe careful

CIS 191 - Lesson 13

Updating a kernel RPMCentOS 5 kernel "update" using install

[root@star ~]# cat /boot/grub/grub.conf# grub.conf generated by anaconda## Note that you do not have to rerun grub after making changes to this file# NOTICE: You have a /boot partition. This means that# all kernel and initrd paths are relative to /boot/, eg.# root (hd0,1)# kernel /vmlinuz-version ro root=/dev/sda3# initrd /initrd-version.img#boot=/dev/sda2default=0timeout=35splashimage=(hd0,1)/grub/splash.xpm.gz#hiddenmenutitle CentOS (2.6.18-8.el5) root (hd0,1) kernel /vmlinuz-2.6.18-8.el5 ro root=LABEL=/ rhgb initrd /initrd-2.6.18-8.el5.imgtitle FreeDOS rootnoverify (hd0,0) chainloader +1[root@star ~]#

Note: This is on the star VM

CIS 191 - Lesson 13


[root@star ~]# yum install kernelLoading "installonlyn" pluginSetting up Install ProcessSetting up repositoriesReading repository metadata in from local filesParsing package install argumentsResolving Dependencies--> Populating transaction set with selected packages. Please wait.---> Downloading header for kernel to pack into transaction set.kernel-2.6.18-92.1.13.el5 100% |=========================| 319 kB 00:01---> Package kernel.i686 0:2.6.18-92.1.13.el5 set to be installed--> Running transaction check

Dependencies Resolved

============================================================================= Package Arch Version Repository Size=============================================================================Installing: kernel i686 2.6.18-92.1.13.el5 updates 14 M


Total download size: 14 MIs this ok [y/N]: y

New kernel version available

User confirms here

CIS 191 - Lesson 13


Downloading Packages:(1/1): kernel-2.6.18-92.1 100% |=========================| 14 MB 01:15warning: rpmts_HdrFromFdno: Header V3 DSA signature: NOKEY, key ID e8562897Importing GPG key 0xE8562897 "CentOS-5 Key (CentOS 5 Official Signing Key) <[email protected]>" from http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5

Is this ok [y/N]: yRunning Transaction TestFinished Transaction TestTransaction Test SucceededRunning Transaction Installing: kernel ######################### [1/1]

Installed: kernel.i686 0:2.6.18-92.1.13.el5Complete![root@star ~]#

New kernel is installed …

CIS 191 - Lesson 13


[root@star ~]# cat /boot/grub/grub.conf# grub.conf generated by anaconda## Note that you do not have to rerun grub after making changes to this file# NOTICE: You have a /boot partition. This means that# all kernel and initrd paths are relative to /boot/, eg.# root (hd0,1)# kernel /vmlinuz-version ro root=/dev/sda3# initrd /initrd-version.img#boot=/dev/sda2default=0timeout=35splashimage=(hd0,1)/grub/splash.xpm.gz#hiddenmenutitle CentOS (2.6.18-92.1.13.el5) root (hd0,1) kernel /vmlinuz-2.6.18-92.1.13.el5 ro root=LABEL=/ rhgb initrd /initrd-2.6.18-92.1.13.el5.imgtitle CentOS (2.6.18-8.el5) root (hd0,1) kernel /vmlinuz-2.6.18-8.el5 ro root=LABEL=/ rhgb initrd /initrd-2.6.18-8.el5.imgtitle FreeDOS rootnoverify (hd0,0) chainloader +1[root@star ~]#

… and grub.conf is modified to show the new kernel boot option

cis 191 - lesson 13 linux kernel. architecture dependent kernel code kernel space process management...

Documents

kernel services

kernel source codehttp

libdesign linux kernel

kernel optionsmake config

linux kernelbuilding

unload modules

new kernelcis

installmake installcleans