Am 12.05.2014 18:08, schrieb Lennart Poettering: > On Sat, 10.05.14 06:56, Michael Biebl ([email protected]) wrote: > >> Am 07.05.2014 21:19, schrieb Gero Treuner: >>> On Wed, May 07, 2014 at 02:32:40PM +0200, Michael Biebl wrote: >>>> Please try the attached net.agent (copy it to /lib/udev/net.agent and >>>> make it executable). >>>> It escapes the interface name before starting an instance of the >>>> service. If you want to run systemctl status, make sure to quote the >>>> name like this: >>>> >>>> systemctl status "ifup@veth\x2ddevmachine.service" >>>> >>>> Please report if that works for you. >>> >>> The patch works fine. Thanks for all. >> >> Thanks for testing. >> >> Thinking more about it, a nicer solution would be, if systemd would >> offer another specifier [0], basically the inverse of %I. >> I.e. you pass a (unescaped) string as instance name and systemd does the >> escaping which then can be used in the unit file. >> >> Let's call that specifier %Y for now. > > Not following here? > > Note that unit names cannot contain unescaped strings. THis is because they > are stored in the file system. Hence you either have to escape strings > manually before including them in unit names, or you let "systemctl" do > this for you automatically, because it detects that you passed an > incompletely escaped string on the command line. But the latter really > just is synctactic sugar to make things easy to use for admins.
Maybe an example makes it clearer. We do have an [email protected] in Debian. This service has [Unit] Description=ifup for %I After=local-fs.target BindTo=sys-subsystem-net-devices-%i.device ... And a corresponding udev rule which activates those instance services. Now, say we have network interface containing a '-'. e.g. because I renamed eth0 to "my-eth". If I run systemctl start [email protected], the resulting BindsTo= is not set properly, my-eth is not escaped. I want a specifier which does the following: Take the instance name and escape it. This has several reasons: 1/ I don't want to re-implement the escaping rules outside of systemd, especially since I don't know the escaping rules. 2/ It's hard to escape the interface name from withing a udev rule, unless I call a shell script, where I do the escaping using sed dances. This is ugly, to say the least. 3/ systemctl status [email protected] is much more intuitive then systemctl status ifup@my\x2deth.service. Auto-completing helps a bit, but it doesn't get the quoting right [0], so the failure mode is very confusing. Has it become clearer with this example? Michael [0] https://bugs.freedesktop.org/show_bug.cgi?id=78388 -- Why is it that all of the instruments seeking intelligent life in the universe are pointed away from Earth?
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