3rd-party/linux-kernel-module-cheat
1
0
Fork 0
mirror of https://github.com/cirosantilli/linux-kernel-module-cheat.git synced 2026-01-23 02:05:57 +01:00
Code Issues Releases Wiki Activity

init: disable all userland processes started from init

Browse Source 
In order to make the system easier to understand.

These include:

* networking
* klogd and syslogd. TODO what are those for? I could not see anything useful that they do.

Also get rid of the useless S20random thing while we are at it.
This commit is contained in:
Ciro Santilli
2018-03-25 19:01:24 +01:00
parent 2927ed330a
commit 2656202dff
6 changed files with 39 additions and 61 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
README.adoc
View File

@@ -846,7 +846,9 @@ But TODO I don't think you can see where you are in the kernel source code and l
Step debug userland processes to understand how they are talking to the kernel.
In guest:
First ensure that <<networking>> is enabled.
Then in guest:
....
/gdbserver.sh /myinsmod.out /hello.ko
@@ -1138,16 +1140,38 @@ Finally, the docs are lying, arguments with dots that come after `-` are still t
./run -e 'init=/init_env_poweroff.sh - /poweroff.out'
....
=== Disable networking
=== Networking
The default BusyBox init scripts enable networking, and there is a 15 second timeout in case your network is down or if your kernel / emulator setup does not support it.
We disable networking by default because it starts an userland process, and we want to keep the number of userland processes to a minimum to make the system more understandable.
We have hacked it up so that you can disable networking with:
To enable it run:
....
./run -f 'lkmc_nonet=y'
/sbin/ifup -a
....
To disable it, run:
....
/sbin/ifdown -a
....
To test it out, try:
....
wget google.com
....
BusyBox' `ping` does not work with hostnames even when networking is working fine:
....
ping google.com
....
TODO why: https://unix.stackexchange.com/questions/124283/busybox-ping-ip-works-but-hostname-nslookup-fails-with-bad-address
To enable networking by default, use the methods documented at <<automatic-startup-commands>>
== KVM
You can make QEMU or gem5 <<gem5-vs-qemu-performance,run faster>> by passing enabling KVM with:
@@ -1864,6 +1888,8 @@ Even mor awesome than `chroot` be to `pivot_root`, but I couldn't get that worki
=== Guest host networking
First ensure that networking is enabled before trying out anything in this section: <<networking>>
==== Host to guest networking
Guest, BusyBox `nc` enabled with `CONFIG_NC=y`: