[Pkg-sysvinit-devel] Bug#746580: sysv-rc: [patch] much improved update-rc.d integration w/ systemd

[Christian Seiler]

(Sorry for the noise, pressed 'send' to soon...)

Am 2015-03-20 15:01, schrieb Raphael Hertzog:
> On Sun, 15 Mar 2015, Christian Seiler wrote:
>> Control: severity -1 important
>> Control: tags -1 + patch
>
> I'm tempted to raise the severity to serious as the current behaviour
> is really bad for packages that ship both native .service files and
> init script.

I was also tempted, but decided to first raise it to important first 
(it
was normal before).

>> I have created a patch that implements the previously missing parts 
>> of
>> systemd integration into update-rc.d, following along the lines of 
>> the
>> patch I have written for deb-systemd-helper (bug #780522).
>
> While this improves the situation, there is at least another corner 
> case.
>
> I really believe that reimplementing "systemctl enable/disable" 
> ourselves
> is a bad choice. I understand it's needed to register this
> enabled/disabled status even when systemd is not installed... but we
> should have stored those information in a directory of our own
> and call all the required "systemctl enable/disable"accordingly when 
> we
> install systemd.
>
> The corner case I just encountered is with "openbsd-inetd". The
> service file is inetd.service but the package ships 
> openbsd-inetd.service
> as a symlink to inetd.service so both names refer to the same unit
> and it effectively masks the init script (/etc/init.d/openbsd-inetd).
>
> Everything is fine except that when deb-systemd-helper enables
> inetd.service it creates inetd.service symlinks. And when you do
> "update-rc.d openbsd-inetd enable/disable", update-rc.d will 
> create/remove
> an openbsd-inetd.service symlink.
>
> So "update-rc.d openbsd-inetd disable" doesn't disable the service
> since inetd.service remains... and enable creates a duplicate symlink
> in multi-user.target.wants.
>
> Using "systemctl enable|disable inetd" works as expected
> but "systemctl enable|disable openbsd-inetd" does not detect
> that openbsd-inetd is a synonym for inetd, and will consider
> that the unit is one coming from a SysV setup since
> /etc/init.d/openbsd-inetd exists...

Note that with bare systemd (at least 215, I didn't test newer 
versions),
this doesn't really work either:

# cat > /lib/systemd/system/a.service <<EOF
[Service]
ExecStart=/bin/true
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target
EOF
# ln -s a.service /lib/systemd/system/b.service
# systemctl daemon-reload
# systemctl enable a.service        # works
Created symlink from 
/etc/systemd/system/multi-user.target.wants/a.service to 
/lib/systemd/system/a.service.
# systemctl disable a.service       # works
Removed symlink /etc/systemd/system/multi-user.target.wants/a.service.
# systemctl enable b.service
Failed to execute operation: No such file or directory

(There is no /etc/init.d/a or /etc/init.d/b, so only systemd's own 
code-
path will be used here.)

So even if update-rc.d didn't do the logic by itself, 
non-Alias=-symlinks
currently don't work with systemctl enable/disable, so your example
wouldn't have worked even if Jessie came only with systemd and insserv 
was
only used for sysv scripts.

Christian