Wiki source code of Openwrt Notes

Version 5.1 by Leon Poon on 2019/01/06 08:42
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3 = initramfs-kernel =
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5 kernel runs /init.
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7 /init is a script which sets INITRAMFS=1 and then execs /sbin/init.
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9 /sbin/init is ELF comes from procd package. What it does (as pid=1):
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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
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21 procd states:
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23 * early (first state):
24 ** coldplug (remount /dev, etc)
25 *** start udevtrigger in subproc
26 *** when udevtrigger completes, hotplug
27 *** when hotplug completes, next state (ubus)
28 * ubus:
29 ** start attempts to connect to ubs
30 ** start ubus as service
31 ** once connection's done then next state (init)
32 * init - read /etc/inittab and run:
33 ** respawn - things that need to keep rerunning once quitted
34 ** askconsole
35 ** askfirst - the "Press Enter to activate this console" message
36 ** sysinit - (usually /etc/init.d/rcS with S) and then next state (running)
37 * running - waits for shutdown signal (usr1/usr2) or reboot (int/term)
38 * shutdown
39 ** runs shutdown command per inittab (also /etc/init.d/rcS but with K)
40 ** when done next state (halt)
41 * halt - kill everything and either enter sleep loop or reboots
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46 = Debian =
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48 Needs devtmpfs in kernel (this seem to be first thing that /sbin/init does.
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