Linux kernel detailed

Kernel design style:

Single Core: Linux

Microkernel: Windows,solaris true Support thread

Redhat,suse

Core: Dynamic load kernel module

Kernel:/lib/modules/"kernel version number command directory"/

How user space accesses and monitors the kernel:/proc,/sys pseudo file system

/proc/sys: Many of the files in the secondary directory are readable and writable

/sys/: Some files can be written

How to set kernel parameter values:

Echo VALUE >/proc/sys/xx

or Stsctl-w Kernar. xx= "XX"

Both of these methods can make the setting effective immediately, but not permanently

Permanently valid: Modify/etc/sysctl.conf

After the modification is complete, execute the SYSCTL-P

Sysctl-a: Displays all kernel parameters and their values

Kernel module Management

LSMOD: List kernel modules

Modprobe mod_name: Loading a module

Modprobe-r mod_name: Uninstalling a module

Modinfo mod_name: View specific information about the module

Insmod: Load Module

Remod Mod_name

Depom:

In addition to core functionality, the kernel has three choices for most functions at compile time:

1, do not use sub-function

2. Compile into kernel module

3. Compile into kernel

How to manually compile the kernel

Make Gconfig:gnome Desktop environment use

Make KCONFIG:KDE desktop environment, need to install graphics development Library

Make Menuconfig: Need to execute in kernel directory

Note: Use make menuconfig to install ncurses

Yum Groupinstall "Development Tools" "Development Libraries"

Menuconfig Compiling kernel steps

Cd/usr/src

Mv/root/linux-3.16.2.tar.xz./

xz-d Linux-3.16.2.tar.xz #解压

Tar xvf Linux-3.16.2.tar #展开

Ln-s linux-3.16.2 Linux #链接

CD Linux

Make Menuconfig

Make

Make Modules_install

Make install

Two compile-time cleanup: It is best to back up the. config file before cleaning up

Make clean

Make Mrproper

Grub-->kernel-->initrd-->rootfs (/sbin/init,/bin/bash)

MKINITRD initrd file path kernel version number

mkinitrd/boot/initrd-' uname-r '. img ' uname-r '

Virtual Machine Implementation compilation system

Add a piece of hard disk, partition it, format it

Mkdir-p/mnt/{boot,sysroot}

mount/dev/sdb1/mnt/boot/

mount/dev/sdb2/mnt/sysroot/

Grub-install--root-directory=/mnt/dev/sdb #装载Grub

[Email protected] ~]# ls/mnt/boot/#grub已经存在

Grub Lost+found

Cp/boot/vmlinuz-2.6.32-220.el6.x86_64/mnt/boot/vmlinuz #复制内核

#创建initrd

mkdir ISO

CD ISO

Zcat/boot/initramfs-2.6.32-220.el6.x86_64.img |cpio-id

VIM Init #修改init的如下行

Mkrootdev-t Ext3-o DEFAULTS,RO/DEV/SDB2

Find. |cpio-h newc--quiet-o |gzip-9 >/mnt/boot/initrd.gz

Vim/mnt/boot/grub/grub.conf

Default=0

Timeout=5

Title My Linux

Root (hd0,0)

Kernel/vmlinux

Initrd/initrd.gz

cd/mnt/sysroot/

MKDIR-PV proc Sys Dev etc/rc.d lib bin sbin boot home var/log usr/{bin,sbin} root tmp

#需要拷贝的两类 1./sbin/* 2./bin/*

cp/sbin/init/mnt/sysroot/sbin/

cp/bin/bash/mnt/sysroot/bin/

Ldd/sbin/init #查看init的依赖库

cp/lib/libsepol.so.1/mnt/sysroot/lib/

cp/lib/libselinux.so.1/mnt/sysroot/lib/

cp/lib/libc.so.6/mnt/sysroot/lib/

cp/lib/libdl.so.2/mnt/sysroot/lib/

Ldd/bin/bash #查看bash的依赖库

cp/lib/libtermcap.so.2/mnt/sysroot/lib/

cp/lib/ld-linux.so.2/mnt/sysroot/lib/

chroot/mnt/sysroot/#测试能否使用, exit

Sync #同步磁盘

Vim/mnt/sysroot/etc/inittab #只需2行, default level and system initialization

Id:3:initdefault:

Si::sysinit:/etc/rc.d/rc.sysinit

Vim/mnt/sysroot/etc/rc.d/rc.sysinit

#!/bin/bash

Echo-e "\twelcome to \033[31mmylinux\033[0m"

/bin/bash

chmod +x/mnt/sysroot/etc/rc.d/rc.sysinit

#需要拷贝的两类 1./sbin/* 2./bin/* Script

dest=/mnt/sysroot/

LIBCP () {

libpath=${1%/*}

[!-D $dest $libpath] && mkdir-p $dest $libpath

[!-e $dest ${1}] && cp $dest $libpath && echo "Copy Lib $ finished."

}

BINCP () {

binpath=${1%/*}

[!-D $dest $binpath] && mkdir-p $dest $binpath

[!-e $dest ${1}] && cp $dest $binpath

For Lib in ' LDd $ | Grep-o "/.*lib\ (64\) \{0,1\}/[^[:space:]]\{1,\}"; Do

LIBCP $lib

Done

}

Read-p "Your command:" cmd

until [$cmd = = ' Q ']; Do

! Which $cmd && echo "wrong command" && read-p "input again:" CMD && continue

Command= ' which $cmd |grep-v "^alias" | Grep-o "[^[:space:]]\{1,\}" '

BINCP $command

echo "Copy $command finished"

Read-p "continue:" cmd

Done

Mount-n do not update/etc/mtab files when mounted

Cat/proc/mounts also has all the file systems mounted

#让这个小系统实现开机, shut down the machine

Cd/mnt/sysroot

Vim Etc/rc.d/init.d/halt

#!/bin/bash

Case $ in

*reboot) command= '/sbin/reboot ';;

*halt) command= '/sbin/halt-p ';;

*) echo "Only call this script by *reboot OR *halt";;

Esac

Case $ in

Start

;;

Stop

;;

Status

;;

*)

echo "Usage: ' basename $ ' {start|stop|status}"

;;

Esac

EXEC $command

CD ETC/RC.D

mkdir RC0.D RC6.D

CD RC0.D

Ln-sv. /init.d/halt S99halt

CD rc6.d/

Ln-sv. /init.d/halt S99reboot

Cd.. /

Vim RC

#!/bin/bash

Run=$1

For I in/etc/rc.d/rc${run}.d/k*; Do

$i Stop

Done

For I in/etc/rc.d/rc${run}.d/s*; Do

$i Start

Done

Vim Etc/inittab

L0:0:WAIT:/ETC/RC.D/RC 0

L6:6:WAIT:/ETC/RC.D/RC 6

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Linux kernel detailed