Wiki source code of Openwrt Notes

Version 17.1 by Leon Poon on 2019/01/06 13:18
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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 Things to do after debootstrap:
45
46 * [[get rid of systemd>>http://without-systemd.org/wiki/index.php/How_to_remove_systemd_from_a_Debian_Stretch_installation]]
47 * set hostname
48 * set root password
49 * /etc/network/interfaces (TODO: swconfig while still in openwrt initramfs space?)
50 * apt-get install net-tools file ntp openssh-server gcc
51 ** net-tools for ifconfig
52 ** gcc for?
53 * read-only root
54
55 Needs CONFIG_DEVTMPFS=y in kernel.
56
57 {{code language="bash"}}
58 mkdir -pv /mnt && mknod /dev/sda b 8 0 && cryptsetup open /dev/sda usb && vgchange -ay vol_grp1 && mount /dev/vol_grp1/logical_vol1 /mnt
59 {{/code}}
60
61 {{code language="bash"}}
62 chroot /mnt /bin/bash
63 {{/code}}
64
65 {{code language="bash"}}
66 mount proc /proc -t proc
67 {{/code}}
68
69 {{code language="bash"}}
70 exec switch_root /mnt /sbin/init
71 {{/code}}
72
73 {{code language="bash"}}
74 ip addr add dev eth0 IP/NM
75 ip link set eth0 up
76 ip route add default via GW
77 {{/code}}
78
79 = Network =
80
81 {{code language="bash"}}
82 sed -re 's/^boot_run_hook/#\0/g' -i /etc/preinit
83 PREINIT=1 . /etc/preinit
84 pi_ifname=eth0.1 preinit_ip
85 pi_ifname=eth0.2 preinit_ip
86 {{/code}}