linux2.4.18----25.文件系統的構建

linux2.4.18----25.文件系統的構建

一. 文件系統的構建
1.busybox的編譯
方法: 用虛擬機的redhat9.0進行編譯
版本: busybox-1.00 -->make menuconfig -->make -->make install

1. cong@msi:/work/os/rootfs/busybox/busybox-1.00$ readelf -a ./busybox | grep "NEEDED"
   
2. 0x00000001 (NEEDED) Shared library: [libm.so.6] -->所以文件系統中需要包含這兩個庫libm與libcrypt，是可選的
   
3. 0x00000001 (NEEDED) Shared library: [libcrypt.so.1]
   
4. 0x00000001 (NEEDED) Shared library: [libc.so.6] -->libc庫是最基礎的任何程庫就需要，是必需的

不需要選擇 []Build BusyBox as a static binary (no shared libs)

2. 內核的修改

1. init/main.c中L128
   
2. //int root_mountflags = MS_RDONLY;
   
3. int root_mountflags = 0

去掉根文件系統的只讀屬性，
其中這個root_mountflags會在mount_root-->read_super中設置/dev/hda1的屬性為MS_RDONLY

3.etc目錄下的文件

1. cong@msi:/work/os/rootfs/ext2/etc$ tree
   
2. .
   
3. ├── fstab -->只需要fstab與rcS
   
4. ├── init.d
   
5. │ └── rcS -->只需要rcS與rcS
   
6. └── mtab -->這個文件是mount程序創建的本身不要文件系統中

fstab的內容:掛載proc

1. cong@msi:/work/os/rootfs/ext2/etc$ cat fstab
   
2. proc /proc proc defaults 0 0

rcS的內容，mount all

1. cong@msi:/work/os/rootfs/ext2/etc$ cat init.d/rcS
   
2. #!/bin/sh
   
3. mount -a

4.制作根文件系統的腳本
cong@msi:/work/os/rootfs/ext2$ cat creatext2.sh

1. 
   
2. #!/bin/sh
   
3. TOPDIR=`pwd`
   
4. create_fs()
   
5. {
   
6. echo "cong: next create fs"
   
7. #create filesystem
   
8. cd /tmp/ext2
   
9. 
   
10. #先創建系統目錄
    
11. sudo mkdir -pv dev/ tmp/ sys/ proc/
    
12. sudo mknod ./dev/tty1 c 4 1
    
13. sudo mknod ./dev/console c 5 1
    
14. #sudo cp $TOPDIR/busybox ./bin/
    
15. #sudo cp $TOPDIR/src/hello ./bin/sh
    
16. sudo cp -arf $TOPDIR/lib ./
    
17. sudo cp -arf $TOPDIR/bin ./
    
18. sudo cp -arf $TOPDIR/sbin ./
    
19. sudo cp -arf $TOPDIR/etc ./
    
20. }
    
21. mount_fs()
    
22. {
    
23. echo "cong: next losetup /dev/loop0"
    
24. sudo losetup /dev/loop0 ./hdc.img
    
25. #512*2048=1048576
    
26. echo "cong: next losetup /dev/loop1"
    
27. sudo losetup -o 1048576 /dev/loop1 /dev/loop0
    
28. echo "cong: next show losetup all"
    
29. sudo losetup -a
    
30. 
    
31. echo "cong: next mount "
    
32. mkdir /tmp/ext2
    
33. sudo mount -t ext2 /dev/loop1 /tmp/ext2/
    
34. }
    
35. #fdisk hdc.img to ext2 83
    
36. make_fs()
    
37. {
    
38. #64M
    
39. dd if=/dev/zero of=./hdc.img bs=1M count=64
    
40. fdisk ./hdc.img <<EOF
    
41. n
    
42. p
    
43. 1
    
44. 2048
    
45. 131071
    
46. t
    
47. 83
    
48. w
    
49. EOF
    
50. sleep 1
    
51. fdisk -l ./hdc.img
    
52. 
    
53. echo "cong: next losetup /dev/loop0"
    
54. sudo losetup /dev/loop0 ./hdc.img
    
55. #512*2048=1048576
    
56. echo "cong: next losetup /dev/loop1"
    
57. sudo losetup -o 1048576 /dev/loop1 /dev/loop0
    
58. echo "cong: next show losetup all"
    
59. sudo losetup -a
    
60. 
    
61. echo "cong: next mkfs ext2 /dev/loop1"
    
62. sudo mkfs.ext2 /dev/loop1
    
63. 
    
64. echo "cong: next mount "
    
65. mkdir /tmp/ext2
    
66. sudo mount -t ext2 /dev/loop1 /tmp/ext2/
    
67. create_fs
    
68. }
    
69. umount_fs()
    
70. {
    
71. sudo umount /tmp/ext2
    
72. sudo losetup -d /dev/loop0
    
73. sudo losetup -d /dev/loop1
    
74. sudo losetup -a
    
75. }
    
76. 
    
77. clean_fs()
    
78. {
    
79. echo "cong: next umount /tmp/ext2"
    
80. sudo umount /tmp/ext2
    
81. echo "cong: next rm -rf /tmp/ext2"
    
82. sudo rm -rf /tmp/ext2
    
83. echo "cong: next losetup -d"
    
84. sudo losetup -d /dev/loop0
    
85. sudo losetup -d /dev/loop1
    
86. echo "cong: next show losetup"
    
87. sudo losetup -a
    
88. echo "cong: next rm -rf ./hdc.img"
    
89. rm -rf ./hdc.img
    
90. }
    
91. 
    
92. case "$1" in
    
93. fs)
    
94. make_fs
    
95. ;;
    
96. clean)
    
97. clean_fs
    
98. ;;
    
99. mount)
    
100. mount_fs
     
101. ;;
     
102. umount)
     
103. umount_fs
     
104. ;;
     
105. *)
     
106. make_fs
     
107. ;;
     
108. esac

5.用到的

1. cong@msi:/work/os/rootfs/ext2$ tree
   
2. .
   
3. ├── bin -->會復制為根文件系統的bin目錄
   
4. │ ├── busybox
   
5. │ ├── busybox_0.60.5
   
6. │ ├── cat -> busybox
   
7. │ ├── cp -> busybox
   
8. │ ├── df -> busybox
   
9. │ ├── dmesg -> busybox
   
10. │ ├── echo -> busybox
    
11. │ ├── grep -> busybox
    
12. │ ├── hostname -> busybox
    
13. │ ├── ln -> busybox
    
14. │ ├── ls -> busybox
    
15. │ ├── mkdir -> busybox
    
16. │ ├── mknod -> busybox
    
17. │ ├── mount -> busybox
    
18. │ ├── mv -> busybox
    
19. │ ├── netstat -> busybox
    
20. │ ├── ping -> busybox
    
21. │ ├── ps -> busybox
    
22. │ ├── pwd -> busybox
    
23. │ ├── rm -> busybox
    
24. │ ├── sh -> busybox
    
25. │ ├── sync -> busybox
    
26. │ ├── touch -> busybox
    
27. │ ├── umount -> busybox
    
28. │ └── vi -> busybox
    
29. ├── creatext2.sh -->制作根文件系統的腳本
30. ├── etc -->會復制為根文件系統的etc目錄
    
31. │ ├── fstab
    
32. │ ├── init.d
    
33. │ │ └── rcS
    
34. │ └── mtab
    
35. ├── lib -->會復制為根文件系統的lib目錄
    
36. │ ├── ld-linux.so.2 //解釋器
    
37. │ ├── libc-2.3.2.so //libc庫，這是最基礎的
    
38. │ ├── libcrypt-2.3.2.so //剩下的libcrypt與libm庫單跑helloworld是不需要的
    
39. │ ├── libcrypt.so.1 -> libcrypt-2.3.2.so
    
40. │ ├── libc.so.6 -> libc-2.3.2.so//但這兒的busybox用到了，就添加上了
    
41. │ ├── libm-2.3.2.so
    
42. │ └── libm.so.6 -> libm-2.3.2.so
    
43. ├── Makefile
    
44. ├── sbin -->會復制為根文件系統的sbin目錄
    
45. │ ├── ifconfig -> ../bin/busybox
    
46. │ ├── init -> ../bin/busybox
    
47. │ ├── insmod -> ../bin/busybox
    
48. │ ├── lsmod -> ../bin/busybox
    
49. │ ├── modprobe -> ../bin/busybox
    
50. │ └── rmmod -> ../bin/busybox
    
51. └── src -->一些測試程序的代碼
    
52. ├── as
    
53. │ ├── hello.s
    
54. │ └── Makefile
    
55. ├── hello.c
    
56. ├── Makefile
    
57. ├── mycompile.sh
    
58. └── nasm
    
59. ├── hello
    
60. ├── hello.o
    
61. ├── hello.s
    
62. ├── hello.s_nasm
    
63. ├── init.c_hello
    
64. └── Makefile
    
65. 
    
66. 8 directories, 54 files

5.1 所用到的文件打包
ext2.rar(下載後改名為ext2.tar.gz)