chroot

1. /*********************************************************************************
2. * Linux chroot 并使用之前系统设备节点
3. * 说明：
4. * 直接使用chroot结果/dev下没有设备，所有有些东西需要提前挂载，在进入chroot。
5. *
6. * 2016-12-30 深圳 南山平山村 曾剑锋
7. ********************************************************************************/
8.  
9. 一、参考文档：
10. . mount dev, proc, sys in a chroot environment?
11. http://superuser.com/questions/165116/mount-dev-proc-sys-in-a-chroot-environment
12.  
13. 二、主要Linux Shell命令：
14. . mount /dev/mmcblk0p2 /mnt
15. . mount -t proc proc /mnt/proc
16. . mount -t sysfs sys /mnt/sys
17. . mount -o bind /dev /mnt/dev
18. . chroot /mnt/
19.  
20. 三、实际操作及数据：
21. [zengjf@root ~]# df
22. Filesystem 1K-blocks Used Available Use% Mounted on
23. /dev/root % /
24. tmpfs % /dev/shm
25. tmpfs % /tmp
26. tmpfs % /run
27. [zengjf@root ~]# mount /dev/mmcblk0p2 /mnt
28. EXT3-fs: barriers not enabled
29. kjournald starting. Commit interval seconds
30. EXT3-fs (mmcblk0p2): warning: checktime reached, running e2fsck is recommended
31. EXT3-fs (mmcblk0p2): using internal journal
32. EXT3-fs (mmcblk0p2): recovery complete
33. EXT3-fs (mmcblk0p2): mounted filesystem with writeback data mode
34. [zengjf@root ~]# mount -t proc proc /mnt/proc
35. [zengjf@root ~]# mount -t sysfs sys /mnt/sys
36. [zengjf@root ~]# mount -o bind /dev /mnt/dev
37. [zengjf@root ~]# chroot /mnt/
38.  
39. BusyBox v1.20.2 () built-in shell (ash)
40. Enter ‘help’ for a list of built-in commands.
41.  
42. [zengjf@root /]# ls /dev/
43. alarm ptyr8 tty26 ttyr1
44. apm_bios ptyr9 tty27 ttyr2
45. buzzer ptyra tty28 ttyr3
46. console ptyrb tty29 ttyr4
47. cpu_dma_latency ptyrc tty3 ttyr5
48. fb0 ptyrd tty30 ttyr6
49. fb1 ptyre tty31 ttyr7
50. fb2 ptyrf tty32 ttyr8
51. full ptys0 tty33 ttyr9
52. galcore ptys1 tty34 ttyra
53. i2c- ptys2 tty35 ttyrb
54. i2c- ptys3 tty36 ttyrc
55. i2c- ptys4 tty37 ttyrd
56. i2c- ptys5 tty38 ttyre
57. input ptys6 tty39 ttyrf
58. kmem ptys7 tty4 ttys0
59. kmsg ptys8 tty40 ttys1
60. log ptys9 tty41 ttys2
61. mem ptyt2 tty5 ttysb
62. mmcblk0 ptyt3 tty50 ttysc
63. mmcblk0boot0 ptyt4 tty51 ttysd
64. mmcblk0boot1 ptyt5 tty52 ttyse
65. mmcblk0p1 ptyt6 tty53 ttysf
66. mmcblk0p2 ptyt7 tty54 ttyt0
67. mx6check ptyt8 tty55 ttyt1
68. mxc_asrc ptyt9 tty56 ttyt2
69. mxc_ipu ptyta tty57 ttyt3
70. mxc_vpu ptytb tty58 ttyt4
71. mxs_viim ptytc tty59 ttyt5
72. network_latency ptytd tty6 ttyt6
73. network_throughput ptyte tty60 ttyt7
74. null ptytf tty61 ttyt8
75. …
76. [zengjf@root /]# ls sys
77. block class devices fs kernel power
78. bus dev firmware fsl_otp module
79. [zengjf@root /]# ls proc
80. cpuinfo mounts
81. crypto mtd
82. devices net
83. diskstats pagetypeinfo
84. dri partitions
85. driver scsi
86. execdomains self
87. fb slabinfo
88. filesystems softirqs
89. fs stat
90. interrupts swaps
91. iomem sys
92. ioports sysrq-trigger
93. irq sysvipc
94. kallsyms timer_list
95. apm kmsg tty
96. asound kpagecount uptime
97. buddyinfo kpageflags version
98. bus loadavg vmallocinfo
99. cmdline locks vmstat
100. config.gz meminfo zoneinfo
101. consoles misc
102. cpu modules
103. [zengjf@root /]# df
104. Filesystem 1K-blocks Used Available Use% Mounted on
105. /dev/root % /
106. devpts % /dev/pts
107. tmpfs % /dev/shm
108. tmpfs % /tmp
109. df: /run: No such file or directory
110. /dev/mmcblk0p2 % /
111. /dev/root % /dev
112. [zengjf@root /]# exit
113. [zengjf@root ~]# df
114. Filesystem 1K-blocks Used Available Use% Mounted on
115. /dev/root % /
116. tmpfs % /dev/shm
117. tmpfs % /tmp
118. tmpfs % /run
119. /dev/mmcblk0p2 % /mnt
120. /dev/root % /mnt/dev
121. [zengjf@root ~]#

把/etc/default/grub 中上面红框中的内容去掉，再执行grub2-mkconfig -o /boot/grub2/grub.cfg。
在grub启动命令行中把resume=xxxxxx去掉。