Wiki source code of Openwrt Notes

Version 40.1 by Leon Poon on 2019/11/02 06:19
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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 = Modules =
43
44 {{code}}
45 cp -va ./build_dir/target-*/linux-*/linux-4*/modules.builtin ./staging_dir/target-*/root-*/lib/modules/4*
46 # tar -C ./staging_dir/target-*/root-*/ -vcjf modules.tar.bz2 lib/modules
47 {{/code}}
48
49 = Debian =
50
51 {{code}}
52 debootstrap --variant=minbase --include locales,sudo,sysvinit-core,sysvinit-utils,vim-nox,screen,wget,ntp,bridge-utils,ifupdown --exclude=nano,vim-tiny --foreign stretch $PWD
53 chroot $PWD debootstrap/debootstrap --second-stage
54 {{/code}}
55
56 {{code}}
57 qemu-debootstrap --include=locales,sudo,sysvinit-core,sysvinit-utils,vim-nox,screen,wget,ntp,bridge-utils,ifupdown --exclude=nano,vim-tiny,systemd,systemd-sysv --arch mipsel stretch $PWD
58 {{/code}}
59
60 Do not install openssh-server during bootstrap otherwise it will bring in systemd!
61
62 Things to do after debootstrap:
63
64 * [[get rid of systemd>>http://without-systemd.org/wiki/index.php/How_to_remove_systemd_from_a_Debian_Stretch_installation]]
65 * set hostname
66 * set root password
67 * /etc/network/interfaces (TODO: swconfig while still in openwrt initramfs space?)
68 * apt-get install ~-~-no-install-recommends openssh-server (check that it is without libpam-systemd and systemd!!)
69 * apt-get install net-tools file ntp openssh-server gcc
70 ** net-tools for ifconfig
71 ** gcc for?
72 * echo vm.min_free_kbytes=16384 > /etc/sysctl.d/min_free_kbytes.conf
73 * kernel modules ( tar -C ./staging_dir/target-*/root-*/ -vcjf - lib/modules | ssh TARGET_IP tar -C /chroot -vxjf - )
74 * read-only root
75
76 Needs CONFIG_DEVTMPFS=y in kernel.
77
78 {{code language="bash"}}
79 mkdir -pv /mnt &&
80 mknod /dev/sda b 8 0 &&
81 cryptsetup open /dev/sda usb &&
82 vgchange -ay vol_grp1 &&
83 mount /dev/vol_grp1/logical_vol1 /mnt -o ro
84 {{/code}}
85
86 {{code language="bash"}}
87 chroot /mnt /bin/bash
88 {{/code}}
89
90 {{code language="bash"}}
91 mount proc /proc -t proc
92 {{/code}}
93
94 {{code language="bash"}}
95 exec switch_root /mnt /sbin/init
96 {{/code}}
97
98 {{code language="bash"}}
99 ip addr add dev eth0 IP/NM
100 ip link set eth0 up
101 ip route add default via GW
102 {{/code}}
103
104 = Network =
105
106 {{code language="bash"}}
107 sed -re 's/^boot_run_hook/#\0/g' -i /etc/preinit
108 PREINIT=1 . /etc/preinit
109 preinit_config_board # set up the switch and lan ports on eth0.2, and create ip link
110 json_select switch
111 json_select switch0
112 json_add_boolean reset 0 # do not reset when setting up wan ports on eth0.1
113 json_select ..
114 json_select ..
115 preinit_config_switch switch0 eth0.1 # set up wan ports
116 preinit_ip_config eth0.1 # create ip link
117 ip address flush dev eth0 # del default address
118 for pi_ifname in eth0.1 eth0.2; do
119 ip -4 address flush dev $pi_ifname # del default address
120 ip link set dev $pi_ifname down
121 done
122 {{/code}}
123
124
125 = UBI =
126
127 {{code language="text"}}define Build/append-ubi
128 sh $(TOPDIR)/scripts/ubinize-image.sh \
129 $(if $(UBOOTENV_IN_UBI),--uboot-env) \
130 $(if $(KERNEL_IN_UBI),--kernel $(IMAGE_KERNEL)) \
131 $(foreach part,$(UBINIZE_PARTS),--part $(part)) \
132 $(IMAGE_ROOTFS) \
133 $@.tmp \
134 -p $(BLOCKSIZE:%k=%KiB) -m $(PAGESIZE) \
135 $(if $(SUBPAGESIZE),-s $(SUBPAGESIZE)) \
136 $(if $(VID_HDR_OFFSET),-O $(VID_HDR_OFFSET)) \
137 $(UBINIZE_OPTS)
138 cat $@.tmp >> $@
139 rm $@.tmp
140 endef{{/code}}
141 ~{~{/code}}
142 ~{~{/code}}