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Changes for page Openwrt Notes

Last modified by Leon Poon on 2019/11/02 17:53
From version 1.1
edited by Leon Poon
on 2019/01/05 14:43
Change comment: There is no comment for this version
To version 31.1
edited by Leon Poon
on 2019/09/22 05:47
Change comment: There is no comment for this version

Summary

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Title
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1 -Openwrt Boot Notes
1 +Openwrt Notes
Content
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6 6  
7 7  /init is a script which sets INITRAMFS=1 and then execs /sbin/init.
8 8  
9 -/sbin/init is ELF comes from procd package. What it does:
9 +/sbin/init is ELF comes from procd package. What it does (as pid=1):
10 10  
11 -* early:
11 +* early (different from procd early):
12 12  ** mount /proc, /sysfs, and create /dev nodes, create /tmp subdirs etc
13 13  ** set PATH
14 -* kmodloader in subprocess
14 +* kmodloader in subprocess (waits until done)
15 15  * preinit
16 16  ** plugd in subprocess (seem to deal with firmware)
17 17  ** /etc/preinit in subprocess
18 -* when /etc/preinit is done then it execs and replaces itself with the "real" /sbin/procd
18 +* when /etc/preinit is done then it execvp the "real" /sbin/procd
19 19  
20 -
20 +procd states:
21 +
22 +* early (first state):
23 +** coldplug (remount /dev, etc)
24 +*** start udevtrigger in subproc
25 +*** when udevtrigger completes, hotplug
26 +*** when hotplug completes, next state (ubus)
27 +* ubus:
28 +** start attempts to connect to ubs
29 +** start ubus as service
30 +** once connection's done then next state (init)
31 +* init - read /etc/inittab and run:
32 +** respawn - things that need to keep rerunning once quitted
33 +** askconsole
34 +** askfirst - the "Press Enter to activate this console" message
35 +** sysinit - (usually /etc/init.d/rcS with S) and then next state (running)
36 +* running - waits for shutdown signal (usr1/usr2) or reboot (int/term)
37 +* shutdown
38 +** runs shutdown command per inittab (also /etc/init.d/rcS but with K)
39 +** when done next state (halt)
40 +* halt - kill everything and either enter sleep loop or reboots
41 +
42 += Debian =
43 +
44 +{{code}}
45 +qemu-debootstrap --include=locales,sudo,sysvinit-core,sysvinit-utils,vim-nox,openssh-server --exclude=nano,vim-tiny,systemd,systemd-sysv --arch mipsel stretch /mnt/cdrom
46 +{{/code}}
47 +
48 +Things to do after debootstrap:
49 +
50 +* [[get rid of systemd>>http://without-systemd.org/wiki/index.php/How_to_remove_systemd_from_a_Debian_Stretch_installation]]
51 +* set hostname
52 +* set root password
53 +* /etc/network/interfaces (TODO: swconfig while still in openwrt initramfs space?)
54 +* apt-get install net-tools file ntp openssh-server gcc
55 +** net-tools for ifconfig
56 +** gcc for?
57 +* read-only root
58 +
59 +Needs CONFIG_DEVTMPFS=y in kernel.
60 +
61 +{{code language="bash"}}
62 +mkdir -pv /mnt &&
63 +mknod /dev/sda b 8 0 &&
64 +cryptsetup open /dev/sda usb &&
65 +vgchange -ay vol_grp1 &&
66 +mount /dev/vol_grp1/logical_vol1 /mnt -o ro
67 +{{/code}}
68 +
69 +{{code language="bash"}}
70 +chroot /mnt /bin/bash
71 +{{/code}}
72 +
73 +{{code language="bash"}}
74 +mount proc /proc -t proc
75 +{{/code}}
76 +
77 +{{code language="bash"}}
78 +exec switch_root /mnt /sbin/init
79 +{{/code}}
80 +
81 +{{code language="bash"}}
82 +ip addr add dev eth0 IP/NM
83 +ip link set eth0 up
84 +ip route add default via GW
85 +{{/code}}
86 +
87 += Network =
88 +
89 +{{code language="bash"}}
90 +sed -re 's/^boot_run_hook/#\0/g' -i /etc/preinit
91 +PREINIT=1 . /etc/preinit
92 +preinit_config_board # set up the switch and lan ports on eth0.2, and create ip link
93 +json_select switch
94 +json_select switch0
95 +json_add_boolean reset 0 # do not reset when setting up wan ports on eth0.1
96 +json_select ..
97 +json_select ..
98 +preinit_config_switch switch0 eth0.1 # set up wan ports
99 +preinit_ip_config eth0.1 # create ip link
100 +ip address flush dev eth0 # del default address
101 +for pi_ifname in eth0.1 eth0.2; do
102 + ip -4 address flush dev $pi_ifname # del default address
103 + ip link set dev $pi_ifname down
104 +done
105 +{{/code}}
106 +
107 +
108 += UBI =
109 +
110 +{{code language="text"}}define Build/append-ubi
111 + sh $(TOPDIR)/scripts/ubinize-image.sh \
112 + $(if $(UBOOTENV_IN_UBI),--uboot-env) \
113 + $(if $(KERNEL_IN_UBI),--kernel $(IMAGE_KERNEL)) \
114 + $(foreach part,$(UBINIZE_PARTS),--part $(part)) \
115 + $(IMAGE_ROOTFS) \
116 + $@.tmp \
117 + -p $(BLOCKSIZE:%k=%KiB) -m $(PAGESIZE) \
118 + $(if $(SUBPAGESIZE),-s $(SUBPAGESIZE)) \
119 + $(if $(VID_HDR_OFFSET),-O $(VID_HDR_OFFSET)) \
120 + $(UBINIZE_OPTS)
121 + cat $@.tmp >> $@
122 + rm $@.tmp
123 +endef{{/code}}
124 +~{~{/code}}