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[[!meta copyright="Copyright © 2013, 2014 Free Software Foundation, Inc."]]
[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
id="license" text="Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with no Invariant
Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license
is included in the section entitled [[GNU Free Documentation
License|/fdl]]."]]"""]]
Upstart is an event based init system that is GPL licensed, however upstream
contributions are under a CLA that permits proprietary relicensing.
As of Jan 2 2013, Debian is considering adopting Upstart as an init system on
GNU/Linux, and on GNU/kFreeBSD when the port to kFreeBSD is finished.
The following are the words of Colin Watson on the debian-ctte@lists.debian.org
mailing list and list the requirements of a potential HURD port:
>I haven't looked at this in much detail, and I suspect Dimitri hasn't
yet although IIRC he did express some interest in doing so. But I
haven't seen anyone else try to outline the scope of a port, so let me
try to do so for the sake of general understanding. As far as I know,
the hardest parts would be inotify, ptrace, and prctl
(PR_SET_CHILD_SUBREAPER).
>inotify is used to notice changes to configuration files. This is
certainly helpful for users, but it isn't critical as "initctl
reload-configuration" works without it. We could probably do without
this with the aid of a dpkg trigger.
>ptrace is used for "expect fork" and "expect daemon"; as I indicated in
another post, I think it would be preferable to avoid these in Debian
and quite possibly to compile them out. (This would mean we wouldn't be
able to translate Ubuntu jobs quite as directly, and a number of
important jobs would definitely need to be changed, but the conversion
isn't usually particularly difficult.)
>prctl (PR_SET_CHILD_SUBREAPER) is used to make SIGCHLD notification work
properly when Upstart is supervising a user session. This isn't a
required feature and could easily be compiled out until suitable kernel
support is available (this actually seems like the sort of thing that
could be done in the Hurd without too much difficulty, but I haven't
looked into it). If absent, it might well impede the ability to do an
advanced desktop port, but it wouldn't get in the way of porting the
bulk of services.
>There might also be odds and ends around the details of wait status
handling.
inotify seems to be a feature that is often used in GNU/Linux programs, and
implementing the feature in the HURD seems like a better and more rewarding
option than porting the code in Upstart.
Although many daemons double fork, that behavior seems to be dying out, and
one can comfortably ignore the "expect fork/daemon" functionality of Upstart
(and compile it out).
[[!tag open_issue_porting]]
See also the discussion about upstart on the [[systemd]] page.
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