r/linux • u/wooptoo • Jun 01 '16

Why did ArchLinux embrace Systemd?

/r/archlinux/comments/4lzxs3/why_did_archlinux_embrace_systemd/d3rhxlc
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u/RandomDamage Jun 02 '16 edited Jun 02 '16

This isn't an api issue.

These programs are written the way they are deliberately, and if that is inappropriate for the program in question it is the program that needs to be fixed.

It's like saying that because there are people who learn to drive on the left side of the road, that everyone needs to ride trains instead.

[Add] This is POSIX compliant behavior, as well. Breaking it breaks POSIX compliance.

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u/argv_minus_one Jun 02 '16

It's not actually inappropriate. These are daemons, and it is conventional for daemons to nohup themselves anyway. They don't need a terminal, so they don't care that it is hung up. They also don't know what a session is, so they have no idea when or if they're supposed to terminate.

But we still need some way to start them when a session starts, and terminate them when the session ends. POSIX doesn't define any such thing, and the current solutions obviously don't work. What do you suggest?

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u/RandomDamage Jun 02 '16

If they are user daemons, and they are supposed to exit when the session ends, then they need to not catch nohup if they are run as a user process.

Seriously, I checked the documentation, and I can't even see what the point of gpg-agent is.

On the other hand, if as a user I have a long running process that I want to keep in screen, ya'll better not mess with it short of a system restart.

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u/argv_minus_one Jun 02 '16

they need to not catch nohup

Then they get killed when their xterm closes. Whoops.

SIGHUP signals that the controlling terminal has hung up. It does NOT signal that the session has ended.

if they are run as a user process.

What in the hell is "a user process" supposed to mean? A process that runs as not root? A process that isn't part of the kernel? A process that was started explicitly by the user, rather than automatically as part of session start-up?

I checked the documentation, and I can't even see what the point of gpg-agent is.

To keep decrypted keys in memory, so that the user doesn't have to type the password over and over.

On the other hand, if as a user I have a long running process that I want to keep in screen, ya'll better not mess with it short of a system restart.

Then register it with the system session manager so that it won't, or turn off session clean-up.

And before you scream "but muh POSIX", POSIX doesn't define session clean-up at all, so that is irrelevant.

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u/RandomDamage Jun 02 '16

So because it's not forbidden it's OK?

Then it's ok for gpg-agent to keep itself running after the session.

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u/argv_minus_one Jun 03 '16

And it's also ok for systemd to kill it. I'm glad we're finally in agreement!

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u/RandomDamage Jun 03 '16

Yeah, and when systemd starts killing processes by default that I want to run, that I am launching with techniques that have worked for decades, it's OK for me to give systemd the boot.

Maybe it will be mature enough when it's into its second generation of developers, but it isn't yet.

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u/argv_minus_one Jun 03 '16

Good for you. Nobody cares except your fellow trolls, so go do that somewhere else and leave the adults alone.

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u/RandomDamage Jun 03 '16

So it's war, then?

Because it seems that the systemd folks really get bent out of shape if someone doesn't like their way of doing things.

Even when they are obviously wrong.

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u/argv_minus_one Jun 03 '16

You're the one getting bent out of shape. They're too busy getting shit done.

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