[Linux 系統(tǒng)裁減指南][5][redkaoliang][doc].doc

1、Linux 系統(tǒng)裁減指南 (LiPS)目 錄目 錄11 引言41.1 編寫目的41.2 背景41.3 定義41.4 參考資料42 總體描述52.1 硬件環(huán)境52.2 軟件環(huán)境52.3 需求規(guī)定和約束53 總體設計63.1 基本設計概念63.2 軟件結構64 內核64.1 創(chuàng)建內核的方法64.2 內核配置74.2.1 概述74.2.2 Loadable module support84.2.3 Processor type and features84.2.4 General setup84.2.5 Plug and Play configuration94.2.6 Block devices9

2、4.2.7 Multi-device support (RAID and LVM)104.2.8 Networking options104.2.9 ATA/IDE/MFM/RLL support114.2.10 SCSI support124.2.11 Network device support124.2.12 Character devices134.2.13 File systems144.2.14 Console drivers154.2.15 USB support154.3 提示164.3.1 EXTRAVERSION164.3.2 .config175 根文件系統(tǒng)175.1 根

3、文件系統(tǒng)175.2 文件系統(tǒng)的內容175.2.1 應用程序（applications）175.2.2 設備文件（device files）185.2.3 腳本和配置文件（scripts and configuration files）195.2.4 庫文件（libraries）205.2.5 必要的目錄205.3 初始化RAM盤（initrd）215.3.1 操作步驟215.3.2 引導選項215.3.3 安裝225.3.4 改變根目錄設備235.3.5 使用場合245.3.6 淘汰的根轉換機制（change_root）245.4 系統(tǒng)初始化（init）245.4.1 init的任務245.4

4、.2 SysVinit255.4.3 兩種風格：Slackware vs. Debian255.5 PAM265.5.1 什么是PAM265.5.2 PAM的結構265.5.3 配置文件265.5.4 other275.6 再論initrd275.6.1 根到底在哪里285.6.2 linuxrc285.6.3 根轉換機制：新的？舊的？305.7 提示315.7.1 文件系統(tǒng)目錄層次結構315.7.2 mklips.sh（制作LiPS的腳本）325.7.3 lips.conf（LiPS配置文件）325.7.4 cp dpR325.7.5 如何判斷一個程序依賴哪些文件325.7.6 帶庫文件復制

5、lcp()335.7.7 庫文件的命名346 引導356.1 引導過程概述356.2 幾種引導方式356.3 grub引導器356.4 USB引導356.4.1 制作步驟3 創(chuàng)建文件系統(tǒng)3 復制文件3 安裝grub366.5 提示376.5.1 版本問題？377 遠程串口控制臺377.1 概述377.2 配置方法377.3 提示377.4 Linux 遠程串口控制臺指南378 系統(tǒng)安裝光盤408.1 概述408.2 boot.iso光盤的文件結構分析401 引言1.1 編寫目的說明Linux系統(tǒng)裁減的過程及解決的主要技術問題。本文檔的編寫是為了說

6、明LiPS的詳細設計過程，也可以作為構造一個小型化Linux系統(tǒng)的指南。本文檔內容的組織如下所述：這一部分是引言，第2部分是對項目軟、硬件環(huán)境和需求的總體描述，第3部分說明了裁減LINUX的相關基本概念。后面幾個部分是具體實現(xiàn)方法的詳細說明，46分別詳細描述了創(chuàng)建內核、創(chuàng)建根文件系統(tǒng)和引導系統(tǒng)的方法。最后的內容可以看作附錄，其中7說明了一般Linux系統(tǒng)安裝光盤的創(chuàng)建方法，8列出了相關的配置文件和源代碼。1.2 背景華中科技大學計算機存儲系統(tǒng)國家專業(yè)實驗室，NAS項目（2003.32003.8）。1.3 定義O boot loader: 引導器O kernel: 內核O root filesy

7、stem: 根文件系統(tǒng)O USB: 通用串行總線1.4 參考資料1 DIY：自己動手做一個迷你 Linux 系統(tǒng). IBM developerWorks 中國網(wǎng)站. /developerWorks/cn/linux/embed/diy/index.shtml2 Linux From Scratch. http:/clfsbook.mylab.idv.tw/index.html3 Linux啟動過程綜述. /forum/showdoc.jsp?l=1&i=157504 The Linux Bootdisk

8、 HOWTO (中譯版). .tw/CLDP/gb/Bootdisk-HOWTO.html5 Using the initial RAM disk (initrd). /usr/src/linux-2.4/Documentation/initrd.txt. （譯文：/Project/3ybaby/discuss-area/cd-boot/cdboot_refer/initrd.htm）6 Quickmouse于2003.1發(fā)表于白云黃鶴BBS (/ Linux討論區(qū)的帖子“裁

9、減Linux”。7 Filesystem Hierarchy Standard. /fhs/pub/fhs-2.2.pdf8 LINUX ALLOCATED DEVICES. /usr/src/linux-2.4/Documentation/device.txt. 或者最新的列表在/pub/linux/docs/device-list/9 Karim Yaghmour. Building Embedded Linux Systems. OReilly, April 2003.10 Alessandro Rubi

10、ni. Take Command: Init. http:/www.linux.it/kerneldocs/init/ , November 1998. 11 深入 Linux PAM 體系結構. IBM developerWorks 中國網(wǎng)站. http:/www-90/0./developerWorks/cn/linux/l-pam/index.shtml . 2003.7.12 2 總體描述2.1 硬件環(huán)境開發(fā)主機：Intel 845芯片組主板，P4賽揚1.8GHz CPU，256M內存，60G IDE硬盤，RTL8139網(wǎng)卡。目標機：與主機同構。2.2 軟件環(huán)境開發(fā)主機：

11、Redhat Linux 7.3 (kernel 2.4.18-3)，或者Redhat Linux 9 (kernel 2.4.20-8)。可以根據(jù)需要使用其他版本的內核，比如Redhat 7.3kernel 2.4.20。目標機：LiPS，以及應用程序。2.3 需求規(guī)定和約束我們目標系統(tǒng)LiPS，即Linux Powered Storage是一個嵌入式Linux操作系統(tǒng)，主要著眼于提供各種文件服務，不包括X GUI；并且足夠小，可以裝入32M USB盤或者DOC/DOM等常用設備引導。3 總體設計3.1 基本設計概念提起“裁減Linux”，最容易想到的方法是以一個已經(jīng)安裝好的系統(tǒng)為基礎，刪除

12、掉不需要的文件，以減小整個系統(tǒng)的尺寸。而事實上這個方法幾乎是行不通的，因為通過光盤安裝的一個Redhat 9 Linux系統(tǒng)，即便是只選擇了比較少的軟件包，其所占空間也可以輕松達到300500MB，想在這個基礎上裁減到30MB左右是比較困難的。更困難的是確定哪些東西是可以刪除的？如果刪除了系統(tǒng)必須的文件，可能導致系統(tǒng)不能引導。另一個途徑是從零開始根據(jù)需要構建整個系統(tǒng)。“Linux From Scratch”采用的就是這種方式，一個個安裝需要的軟件包。類似的，更簡單的方法是，安裝一個完整的Linux系統(tǒng)，然后將必要的軟件（可執(zhí)行程序）、配置文件、庫文件、內核等復制出來構建一個小系統(tǒng)。我們采取后一

13、種方式。3.2 軟件結構LiPS包括3部分：Linux內核，根文件系統(tǒng)和引導器。內核（Kernel）提供了一個操作系統(tǒng)的基本功能，如內存管理、進程調度、文件系統(tǒng)、網(wǎng)絡等，以及設備驅動程序。根文件系統(tǒng)（Root filesystem）是存放運行、維護系統(tǒng)所必須的各種工具軟件、庫文件、腳本、配置文件和其他特殊文件（比如設備節(jié)點）的地方，也可以安裝各種軟件包。通常根文件系統(tǒng)位于某個磁盤分區(qū)，而在LiPS中應用了initrd（初始RAM盤）機制，將根文件系統(tǒng)放在RAM Disk中。引導器（Boot Loader）的任務是從引導設備裝載內核，引導系統(tǒng)運行。Linux系統(tǒng)常見的引導器包括早期的LILO和近

14、期的GRUB。LiPS用的是GRUB。4 內核4.1 創(chuàng)建內核的方法Linux提供了方便靈活的方法來定制內核，主要步驟包括：下載安裝內核源代碼樹，配置內核，編譯內核。具體方法請參考相關文檔。關鍵指令如下： cd /usr/src/linux-2.4 make menuconfig make dep; make clean; make bzImage編譯成功的內核文件為arch/i386/boot/bzImage.4.2 內核配置4.2.1 概述make menuconfig之后可以看到類似如下的內容（編號是為了描述方便而加上的）。根據(jù)內核版本的不同，列出的項目會有差異。而變化主要發(fā)生在發(fā)行版為

15、標準內核打的各種補丁上面，其實標準內核是比較穩(wěn)定的。如下所示，我們配置的內核版本為2.4.20-8，這個“-8”就是Redhat所打的補丁版本號。補丁一般是對標準內核錯誤的修正和新增的功能。與2.4.20內核配置選項比較會發(fā)現(xiàn)，10，25，30都屬于Redhat的補丁。一般地，這些補丁選項都不是必須的，因此我們的LiPS內核中都沒有包括這些選項。其實，完全可以通過直接配置一個標準的內核版本（比如2.4.20）來產(chǎn)生我們所需要的內核。 Linux Kernel v2.4.20-8-R2Lips Configuration1 Code maturity level options -2 Loada

16、ble module support -3 Processor type and features -4 General setup -5 Memory Technology Devices (MTD) -6 Parallel port support -7 Plug and Play configuration -8 Block devices -9 Multi-device support (RAID and LVM) -10 Cryptography support (CryptoAPI) -11 Networking options -12 Telephony Support -13

17、ATA/IDE/MFM/RLL support -14 SCSI support -15 Fusion MPT device support -16 I2O device support -17 Network device support -18 Amateur Radio support -19 IrDA (infrared) support -20 ISDN subsystem -21 Old CD-ROM drivers (not SCSI, not IDE) -22 Input core support -23 Character devices -24 Multimedia dev

18、ices -25 Crypto Hardware support -26 File systems -27 Console drivers -28 Sound -29 USB support -30 Additional device driver support -31 Bluetooth support -32 Kernel hacking -33 Library routines - Load an Alternate Configuration File Save Configuration to an Alternate File 下面我們以2.4.20內核為例，來詳細說明內核的配置

19、，也就是選哪些東西、不選哪些東西。沒有說明的選項，比如“Code maturity level options”，表示不選。4.2.2 Loadable module support * Enable loadable module support Set version information on all module symbols * Kernel module loader可加載模塊支持。雖然目前所選項目全部編譯進內核，但是內核是支持模塊的?？梢钥紤]將一些硬件設備的驅動程序編譯為模塊，從而減小內核尺寸，同時增加適應不同硬件平臺的靈活性。4.2.3 Processor type and

20、 features (Pentium-III/Celeron(Coppermine) Processor family * Machine Check Exception Toshiba Laptop support Dell laptop support /dev/cpu/microcode - Intel IA32 CPU microcode support /dev/cpu/*/msr - Model-specific register support /dev/cpu/*/cpuid - CPU information support (off) High Memory Support

21、 Math emulation MTRR (Memory Type Range Register) support Symmetric multi-processing support Local APIC support on uniprocessors Unsynced TSC support處理器特性。選擇一下Processor family，其余基本上都沒有選。High Memory Support也可以打開，不清楚有什么用。4.2.4 General setup * Networking support * PCI support (Any) PCI access mode * IS

22、A bus support * PCI device name database EISA support MCA support Support for hot-pluggable devices * System V IPC * BSD Process Accounting * Sysctl support (ELF) Kernel core (/proc/kcore) format Kernel support for a.out binaries Kernel support for ELF binaries Kernel support for MISC binaries * Pow

23、er Management support Kernel support for MISC binaries * Power Management support Advanced Power Management BIOS support * Ignore USER SUSPEND * Enable PM at boot time * Make CPU Idle calls when idle * Enable console blanking using APM * RTC stores time in GMT * Allow interrupts during APM BIOS call

24、s * Use real mode APM BIOS call to power off總體設置。這一部分選項比較重要，包括網(wǎng)絡、總線、進程、二進制文件格式、電源管理等。其中APM相關的選項比較搞不清楚，有時候halt p命令不能關閉系統(tǒng)電源跟這里有關系。4.2.5 Plug and Play configuration Plug and Play support ISA Plug and Play support即插即用設置。4.2.6 Block devices Normal floppy disk support XT hard disk support Compaq SMART2 su

25、pport Compaq Smart Array 5xxx support Mylex DAC960/DAC1100 PCI RAID Controller support Loopback device support Network block device support RAM disk support (4096) Default RAM disk size * Initial RAM disk (initrd) support * Per partition statistics in /proc/partitions塊設備。軟驅也可以不選。這里的關鍵選項是Loopback dev

26、ice，RAM disk和initrd，一定要選中。Default RAM disk size多少都沒有關系。4.2.7 Multi-device support (RAID and LVM) * Multiple devices driver support (RAID and LVM) RAID support Linear (append) mode RAID-0 (striping) mode RAID-1 (mirroring) mode RAID-4/RAID-5 mode Multipath I/O support Logical volume manager (LVM) sup

27、portMD支持。軟RAID和LVM的支持在這里選擇，如果不使用，也可以不選。4.2.8 Networking options Packet socket * Packet socket: mmapped IO Netlink device emulation * Network packet filtering (replaces ipchains) Network packet filtering debugging * Socket Filtering Unix domain sockets * TCP/IP networking * IP: multicasting * IP: adv

28、anced router IP: policy routing IP: equal cost multipath IP: use TOS value as routing key IP: verbose route monitoring IP: large routing tables * IP: kernel level autoconfiguration * IP: DHCP support * IP: BOOTP support * IP: RARP support IP: tunneling IP: GRE tunnels over IP IP: multicast routing I

29、P: TCP Explicit Congestion Notification support IP: TCP syncookie support (disabled per default) IP: Netfilter Configuration - 802.1Q VLAN Support - The IPX protocol Appletalk protocol support Appletalk devices - DECnet Support 802.1d Ethernet Bridging QoS and/or fair queueing - Network testing -網(wǎng)絡選

30、項。這里選項也比較多，如果沒有什么特殊要求，又不是十分理解這些選項的意義，基本上可以用缺省設置。注意DHCP選項，如果要用到的話要記得選中這個。IP: Netfilter Configuration（跟iptables有關）等幾個子選項都沒有選。4.2.9 ATA/IDE/MFM/RLL support ATA/IDE/MFM/RLL support IDE, ATA and ATAPI Block devices - Enhanced IDE/MFM/RLL disk/cdrom/tape/floppy support - Please see Documentation/ide.txt f

31、or help/info on IDE drives Use old disk-only driver on primary interface Include IDE/ATA-2 DISK support * Use multi-mode by default * Auto-Geometry Resizing support Include IDE/ATAPI CDROM support Include IDE/ATAPI TAPE support Include IDE/ATAPI FLOPPY support SCSI emulation support IDE Taskfile Acc

32、ess - IDE chipset support/bugfixes CMD640 chipset bugfix/support RZ1000 chipset bugfix/support * Generic PCI IDE chipset support * Sharing PCI IDE interrupts support * Generic PCI bus-master DMA support Boot off-board chipsets first support Force enable legacy 2.0.X HOSTS to use DMA * Use PCI DMA by

33、 default when available Enable DMA only for disks AEC62XX chipset support ALI M15x3 chipset support AMD Viper support CMD64X and CMD680 chipset support CY82C693 chipset support Cyrix CS5530 MediaGX chipset support HPT34X chipset support HPT366/368/370 chipset support * Intel PIIXn chipsets support *

34、 PIIXn Tuning support PROMISE PDC20246|62|65|67|68|69|70 support ServerWorks OSB4/CSB5 chipsets support SiS5513 chipset support SLC90E66 chipset support VIA82CXXX chipset support Other IDE chipset support IGNORE word93 Validation BITSIDE設備支持。要用IDE硬盤，當然要選中。CDROM選項看情況也可以不要。SCSI emulation似乎對使用USB盤有影響。剩

35、下的很多都是跟IDE chipset有關的。最好是用dmesg命令找出目標系統(tǒng)主板芯片組，然后選中對應的芯片組支持，這樣相當于安裝了IDE芯片組的驅動程序。如果沒有指定應該也可以，只是性能可能會受到一些影響。4.2.10 SCSI support SCSI support - SCSI support type (disk, tape, CD-ROM) SCSI disk support (40) Maximum number of SCSI disks that can be loaded as modules SCSI tape support SCSI OnStream SC-x0 ta

36、pe support SCSI CD-ROM support SCSI generic support - Some SCSI devices (e.g. CD jukebox) support multiple LUNs Enable extra checks in new queueing code Probe all LUNs on each SCSI device Verbose SCSI error reporting (kernel size +=12K) SCSI logging facility SCSI low-level drivers -SCSI支持。如果要用到SCSI硬

37、盤等SCSI設備，這里當然要選。目前我們的目標系統(tǒng)其實沒有SCSI硬盤，但是為了使用USB盤，也要選中SCSI支持。SCSI low-level drivers子選項中是一些SCSI卡，都不用選。4.2.11 Network device support * Network device support ARCnet devices - Dummy net driver support Bonding driver support EQL (serial line load balancing) support Universal TUN/TAP device driver support E

38、thernet (10 or 100Mbit) - * Ethernet (10 or 100Mbit) * EISA, VLB, PCI and on board controllers EtherExpressPro/100 support (eepro100, original Becker driver RealTek RTL-8139 PCI Fast Ethernet Adapter support Ethernet (1000 Mbit) - FDDI driver support PPP (point-to-point protocol) support SLIP (seria

39、l line) support Wireless LAN (non-hamradio) - Token Ring devices - Fibre Channel driver support Wan interfaces -網(wǎng)絡設備支持。主要選擇網(wǎng)卡類型，Ethernet (10 or 100Mbit)子選項中列出了內核可以支持的10/100M以太網(wǎng)卡，這里僅列出了我們選中的2種。其他子選項都沒有選。4.2.12 Character devices * Virtual terminal * Support for console on virtual terminal Standard/gen

40、eric (8250/16550 and compatible UARTs) serial support * Support for console on serial port Extended dumb serial driver options Non-standard serial port support Unix98 PTY support I2C support - Mice - Joysticks - QIC-02 tape support Watchdog Cards - AMD 768 Random Number Generator support Intel i8x0

41、Random Number Generator support AMD 76x native power management (Experimental) /dev/nvram support Enhanced Real Time Clock Support Double Talk PC internal speech card support Siemens R3964 line discipline Applicom intelligent fieldbus card support Ftape, the floppy tape device driver - /dev/agpgart

42、(AGP Support) Direct Rendering Manager (XFree86 DRI support) ACP Modem (Mwave) support字符設備。這里主要就是選擇了最前面4個跟終端和串口有關的選項，以支持虛擬終端（遠程登錄要用到），支持標準串口，支持串口控制臺。4.2.13 File systems * Quota support Kernel automounter support Kernel automounter version 4 support (also supports v3) Reiserfs support Enable reiserfs

43、 debug mode * Stats in /proc/fs/reiserfs Ext3 journalling file system support JBD (ext3) debugging support DOS FAT fs support MSDOS fs support UMSDOS: Unix-like file system on top of standard MSDOS fs VFAT (Windows-95) fs support Compressed ROM file system support * Virtual memory file system suppor

44、t (former shm fs) ISO 9660 CDROM file system support * Microsoft Joliet CDROM extensions Transparent decompression extension JFS filesystem support Minix fs support FreeVxFS file system support (VERITAS VxFS(TM) compatible) NTFS file system support (read only) OS/2 HPFS file system support * /proc f

45、ile system support QNX4 file system support (read only) ROM file system support Second extended fs support System V/Xenix/V7/Coherent file system support UDF file system support (read only) UFS file system support (read only) Network File Systems - Coda file system support (advanced network fs) NFS

46、file system support * Provide NFSv3 client support Root file system on NFS NFS server support * Provide NFSv3 server support SMB file system support (to mount Windows shares etc.) Use a default NLS NCP file system support (to mount NetWare volumes) Partition Types - Native Language Support - Default

47、 NLS Option: iso8859-1 Codepage 437 (United States, Canada) Simplified Chinese charset (CP936, GB2312) Traditional Chinese charset (Big5)文件系統(tǒng)。這部分內容比較多，也很重要。首先是Quota，如果目標系統(tǒng)支持這個功能，這里就要選中。然后是選擇要支持的文件系統(tǒng)，常用的有Reiserfs，Ext3，F(xiàn)AT，ISO9660，JFS等等，可以根據(jù)情況選擇。/proc和ext2一定要選中。還有Network File Systems子選項，可以選擇是否支持NFS和SMB。Native Language Support子選項跟所支持的語言有關，這里沒有全部列出來，我們選中了英語和簡體、繁體中文字符集。4.2.14 Console drivers * VGA text console Video mode selection support控制臺驅動。調試的時候可以給目標系統(tǒng)接顯示器看一下，實際系統(tǒng)應該可以不選。4.2.15 USB support Support for USB USB verbose debug messages - Miscellaneous