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Zucca
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Joined: 14 Jun 2007
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Location: Rasi, Finland
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 Posted: Mon Jan 13, 2025 5:32 pm Post subject: |
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| pingtoo wrote: | | One of "init" duty for linux is reap zombie process. |
Ok. I thought this was kernel's job. Is it really so? That would explain one oddity I have...
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| My gentoo installs: | init=/sbin/openrc-init
-systemd -logind -elogind seatd |
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grknight
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Joined: 20 Feb 2015
Posts: 1982
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| Posted: Mon Jan 13, 2025 5:46 pm Post subject: |
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| Zucca wrote: | | pingtoo wrote: | | One of "init" duty for linux is reap zombie process. |
Ok. I thought this was kernel's job. Is it really so? That would explain one oddity I have... |
Yes, it is init's job. See a simple example from openrc-init that catches SIGCHLD and reaps |
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Fulgurance
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Joined: 15 Feb 2017
Posts: 1245
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| Posted: Mon Jan 13, 2025 6:57 pm Post subject: |
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| NeddySeagoon wrote: | Fulgurance,
Lets back off a little.
You have a VM with a boot loader and a kernel and not much else.
What is in /dev is the VM root before anything is started.
You must have at least /dev/null and /dev/console or it all comes to a grinding halt.
The must be device special nodes too.
How does | Code: | | mount --bind /run /run |
work?
--bind makes an already mounted filesystem visible somewhere else ... but you have said nothing about mounting run anywhere.
The kernel has mounted root, then its all up to you.
/run is usually tmpfs, so that it can be rw, even an a read only root fs.
I don't know what the --rbind mounts do either, as those filesystems are not mounted anywhere yet.
needs shared libraries.
| Code: | $ lddtree /bin/bash
/bin/bash (interpreter => /lib64/ld-linux-x86-64.so.2)
libreadline.so.8 => /usr/lib64/libreadline.so.8
libtinfow.so.6 => /lib64/libtinfow.so.6
libtinfo.so.6 => /lib64/libtinfo.so.6
libc.so.6 => /lib64/libc.so.6 |
Start off with a statically linked busybox
Where do you set $PATH ?
mount is actually /bin/mount, so it won't be found with an empty $PATH.
Hint: look at some initrd init scrips. |
Thanks NeddySeagoon. Because of your comment, I realized my mount steps where wrong at some points, so I updated like this:
| Code: |
#!/bin/bash
mount -o remount rw /
mount -o nosuid,noexec,nodev /proc
mount -o nosuid,noexec,nodev /sys
mount -o mode=0755,nosuid /dev
mount /run
mkdir -p /run/lock
chmod 1777 /run/lock
mkdir -p /dev/shm
mount -o nosuid,nodev /dev/shm
mkdir -pv /sys/fs/cgroup
mount -o nosuid,noexec,nodev /sys/fs/cgroup
ln -sf /proc/self/fd/0 /dev/stdin
ln -sf /proc/self/fd/1 /dev/stdout
ln -sf /proc/self/fd/2 /dev/stderr
ln -sfn /proc/self/fd /dev/fd
ln -sf /proc/kcore /dev/core
. /etc/profile
exec zeroinit
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This is the content of my /dev directory after my updated small init script (I exec /bin/bash instead of my init just to check what is mounted):
https://i.ibb.co/s60NPd6/dev.png
Now I have few questions:
-Do I miss something else vital, or do I have the minimum ?
-I understood I have to use openvt and agetty.
So I did this call:
| Code: |
openvt -f -w -c 1 -- /bin/sh -c "agetty - $TERM"
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But why when I press CTRL+ALT+3 for example, I can't open another TTY ?
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My actual project: https://github.com/Fulgurance/ISM
Ingenius Software Manager is a tool to build and manage a Linux system from scratch.
It will able to manage a linux installation just with a given path to the futur root path |
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Fulgurance
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Joined: 15 Feb 2017
Posts: 1245
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| Posted: Wed Jan 15, 2025 3:05 am Post subject: |
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Someone have an idea ?
Basically after I did a minimal setup with a bash script (for tests purpose at the moment), I would like to understand how I can start login session, but with the 7 virtual tty (when you can press CTRL+ALT+number of TTY)
Because when I use the command openvt with agetty, I can login, but can't switch to any other virtual tty.
How can I do this ?
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My actual project: https://github.com/Fulgurance/ISM
Ingenius Software Manager is a tool to build and manage a Linux system from scratch.
It will able to manage a linux installation just with a given path to the futur root path |
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pjp
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Joined: 16 Apr 2002
Posts: 20575
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| Posted: Wed Jan 15, 2025 3:48 am Post subject: |
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I believe you need kernel support. TTY, PTY, VT? I don't recall the details. Maybe it's in the handbook.
I believe 12 is the default. | Code: | $ cat /proc/sys/kernel/pty/nr
12 |
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GDH-gentoo
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Joined: 20 Jul 2019
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Location: South America
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| Posted: Wed Jan 15, 2025 12:50 pm Post subject: |
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| Fulgurance wrote: | | Because when I use the command openvt with agetty, I can login, but can't switch to any other virtual tty. |
Output of ps axf after you log in and get a shell prompt?
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| NeddySeagoon wrote: | I'm not a witch, I'm a retired electronics engineer  |
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Fulgurance
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Joined: 15 Feb 2017
Posts: 1245
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| Posted: Wed Jan 15, 2025 1:10 pm Post subject: |
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Thank you for your help.
So this is the result of first ps axf and then the content of /proc/sys/kernel/pty/nr (it return 0)
https://i.ibb.co/gZZjXf0/Screenshot-20250115-130556.png
So as you see, /proc/sys/kernel/pty/nr return 0
Lsmod return nothing actually, the list is empty. So I guess I missed a step
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My actual project: https://github.com/Fulgurance/ISM
Ingenius Software Manager is a tool to build and manage a Linux system from scratch.
It will able to manage a linux installation just with a given path to the futur root path |
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GDH-gentoo
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Joined: 20 Jul 2019
Posts: 1790
Location: South America
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| Posted: Wed Jan 15, 2025 3:50 pm Post subject: |
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| Fulgurance wrote: | | https://i.ibb.co/gZZjXf0/Screenshot-20250115-130556.png |
When you say "I [...] can't switch to any other virtual tty", does it mean that you just see an empty screen with a blinking cursor when you press CTRL + Alt + number? You have only one single agetty process for /dev/tty1, so not surprising if that's the case. Were you expecting to be greeted with a login prompt on every virtual terminal?
Also, Gentoo's configuration file for sys-apps/sysvinit just runs agetty directly, I don't think that it's necessary to go through openvt.
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| NeddySeagoon wrote: | | I'm not a witch, I'm a retired electronics engineer |
| Ionen wrote: | | As a packager I just don't want things to get messier with weird build systems and multiple toolchains requirements though |
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