Crystal - Send a reboot signal to the kernel (or other signals)

Help & Support
1

Hi guys, I have a question, on a linux system, with crystal, how can I send the reboot signal to the linux kernel to perform a reboot ?

Basically I have the project to write an init system. I would like to understand how a reboot work.

Is it basically first the init system close all process properly and then write some value in /proc to ask for a reboot?

I am asking for reboot, but as well for other request , like a system shutdown

Is it with this ?

If yes, can I have an example please?

2

I find how to do guys.

I will leave an example to help you all if you need to use :slight_smile:

So according to this page: reboot(2) - Linux manual page

module Init
  Syscall.def_syscall reboot, Int64, magic : Int64, magic2 : Int64, op : Int64
end

Init.reboot(magic:  0xfee1dead,
            magic2: 0x28121969,
            op:     0x1234567)

It is quite simple with crystal ! Thanks to the developers !

3 Likes
4

I test this code on my laptop, it works (need run with root), but it’s not work when –cross-compile aarm64 use alpine then run it in the raspberry PI, (of cause it maybe a issue of PI)

5

Just one suggestion zw963, you will be better to test this code under a virtual machine.

Because syscall perform a reboot without performing a proper init shutdown (it don’t interact with the init). It’s not 100% safe basically.

For aarm64, I don’t know sorry :x