Bug-Gentoo: https://bugs.gentoo.org/show_bug.cgi?id=547916

Since commit 5c67cf2 systemd-udevd doesn't close std{in,out,err} anymore, even when running systemd-udevd daemonized (systemd-udevd --daemon).

As result you cannot use Python's subprocess module to start/restart systemd-udevd like you could do in <=systemd-216 for example. That's how I run into that problem:

I tried salt (a configuration management tool) to restart systemd-udevd, see saltstack/salt#14957 (comment)

According to http://www.freedesktop.org/software/systemd/man/daemon.html (9) a daemonized service should connect /dev/null to standard input, output, and error. Can we do the same with systemd-udevd when running daemonized?

PS: You maybe wondering why I am posting this issue here if the Gentoo bug is already closed and marked as fixed:
We thought that running systemd-udevd in foreground would be a workaround but we now run into another problem (https://bugs.gentoo.org/show_bug.cgi?id=551724 & https://bugs.gentoo.org/show_bug.cgi?id=551928) so we are in progress to revert running in foreground and use the daemon again.