Wiki source code of Openwrt Notes

Version 34.1 by Leon Poon on 2019/11/02 05:43
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1
2
3 = initramfs-kernel =
4
5 kernel runs /init.
6
7 /init is a script which sets INITRAMFS=1 and then execs /sbin/init.
8
9 /sbin/init is ELF comes from procd package. What it does (as pid=1):
10
11 * early (different from procd early):
12 ** mount /proc, /sysfs, and create /dev nodes, create /tmp subdirs etc
13 ** set PATH
14 * kmodloader in subprocess (waits until done)
15 * preinit
16 ** plugd in subprocess (seem to deal with firmware)
17 ** /etc/preinit in subprocess
18 * when /etc/preinit is done then it execvp the "real" /sbin/procd
19
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 debootstrap --variant=minbase --include locales,sudo,sysvinit-core,sysvinit-utils,vim-nox,openssh-server,screen,wget,ntp,bridge-utils,ifupdown --exclude=nano,vim-tiny --foreign stretch $PWD
46 chroot $PWD debootstrap/debootstrap --second-stage
47 {{/code}}
48
49 {{code}}
50 qemu-debootstrap --include=locales,sudo,sysvinit-core,sysvinit-utils,vim-nox,openssh-server,screen,wget,ntp,bridge-utils,ifupdown --exclude=nano,vim-tiny,systemd,systemd-sysv --arch mipsel stretch /mnt/cdrom
51 {{/code}}
52
53 Things to do after debootstrap:
54
55 * [[get rid of systemd>>http://without-systemd.org/wiki/index.php/How_to_remove_systemd_from_a_Debian_Stretch_installation]]
56 * set hostname
57 * set root password
58 * /etc/network/interfaces (TODO: swconfig while still in openwrt initramfs space?)
59 * apt-get install net-tools file ntp openssh-server gcc
60 ** net-tools for ifconfig
61 ** gcc for?
62 * read-only root
63
64 Needs CONFIG_DEVTMPFS=y in kernel.
65
66 {{code language="bash"}}
67 mkdir -pv /mnt &&
68 mknod /dev/sda b 8 0 &&
69 cryptsetup open /dev/sda usb &&
70 vgchange -ay vol_grp1 &&
71 mount /dev/vol_grp1/logical_vol1 /mnt -o ro
72 {{/code}}
73
74 {{code language="bash"}}
75 chroot /mnt /bin/bash
76 {{/code}}
77
78 {{code language="bash"}}
79 mount proc /proc -t proc
80 {{/code}}
81
82 {{code language="bash"}}
83 exec switch_root /mnt /sbin/init
84 {{/code}}
85
86 {{code language="bash"}}
87 ip addr add dev eth0 IP/NM
88 ip link set eth0 up
89 ip route add default via GW
90 {{/code}}
91
92 = Network =
93
94 {{code language="bash"}}
95 sed -re 's/^boot_run_hook/#\0/g' -i /etc/preinit
96 PREINIT=1 . /etc/preinit
97 preinit_config_board # set up the switch and lan ports on eth0.2, and create ip link
98 json_select switch
99 json_select switch0
100 json_add_boolean reset 0 # do not reset when setting up wan ports on eth0.1
101 json_select ..
102 json_select ..
103 preinit_config_switch switch0 eth0.1 # set up wan ports
104 preinit_ip_config eth0.1 # create ip link
105 ip address flush dev eth0 # del default address
106 for pi_ifname in eth0.1 eth0.2; do
107 ip -4 address flush dev $pi_ifname # del default address
108 ip link set dev $pi_ifname down
109 done
110 {{/code}}
111
112
113 = UBI =
114
115 {{code language="text"}}define Build/append-ubi
116 sh $(TOPDIR)/scripts/ubinize-image.sh \
117 $(if $(UBOOTENV_IN_UBI),--uboot-env) \
118 $(if $(KERNEL_IN_UBI),--kernel $(IMAGE_KERNEL)) \
119 $(foreach part,$(UBINIZE_PARTS),--part $(part)) \
120 $(IMAGE_ROOTFS) \
121 $@.tmp \
122 -p $(BLOCKSIZE:%k=%KiB) -m $(PAGESIZE) \
123 $(if $(SUBPAGESIZE),-s $(SUBPAGESIZE)) \
124 $(if $(VID_HDR_OFFSET),-O $(VID_HDR_OFFSET)) \
125 $(UBINIZE_OPTS)
126 cat $@.tmp >> $@
127 rm $@.tmp
128 endef{{/code}}
129 ~{~{/code}}