Re: interesting claims

From: Guillermo <gdiazhartusch_at_gmail.com>
Date: Mon, 29 Apr 2019 23:49:24 -0300

El lun., 29 abr. 2019 a las 16:46, Jeff escribió:
>
> "suckless init is incorrect, because it has no supervision capabilities,
> and thus, killing all processes but init can brick the machine."
>
> a rather bold claim IMO !
> where was the "correct" init behaviour specified ?
> where can i learn how a "correct" init has to operate ?
> [...]
> there is actually NO need for a "correct" working init implementation
> to provide respawn capabilities at all IMO.

This was discussed in the mailing list, you'll be able to find
relevant messages in the archives, and the last part of the sentence
you quoted should clarify what "correct" means in this context. But to
recap:

* A failure mode is identified (the machine becomes unusable and
requires a hard reboot), along with the condition that triggers it
(death of all processes except #1).
* The condition can be triggered explicitly with a kill(-1, SIGKILL)
call in a process with root privileges, so by definition it is not an
impossible condition, but this is not the only way to trigger it.
Processes can die for a variety of reasons.
* An program with "respawn capabilities" running as process 1 can
avoid entering this failure mode, a program that does not have the
capabilities, cannot.

Nothing more, nothing less. This is not a statement about how likely
this failure mode is, only that it exists. An init system can or
cannot choose to prevent it, this is a design choice (and usage of
"correct" will give you an idea of what the author of this particular
software package thinks), and a person may or may not decide to use an
init system that doesn't, this is a matter of preference.

G:
Received on Tue Apr 30 2019 - 02:49:24 UTC