Some symbolic link files of dbus.socket

[HyungJun Choi]

Hello? 

I have a question about 'Makefile.am' in /bus directory.

Could you please explain why below codes are needed for systemd? 
Why systemd needs the symbolic link files of dbus.socket at the different
directory?
All symbolic like files are needed during the booting time? 
For example,
ln -fs ../dbus.socket
$(DESTDIR)$(systemdsystemunitdir)/dbus.target.wants/dbus.socket
ln -fs ../dbus.socket
$(DESTDIR)$(systemdsystemunitdir)/sockets.target.wants/dbus.socket
ln -fs ../dbus.service
$(DESTDIR)$(systemdsystemunitdir)/multi-user.target.wants/dbus.service



The contents of 'Makefile.am' in /bus directory.
...
if HAVE_SYSTEMD
# Install dbus.socket as default implementation of a D-Bus stack.
# Deliberately not using $(LN_S) here: ln -fs is not universally portable,
# but neither is systemd, so it's OK to assume here that ln complies with
SUS.
    $(mkinstalldirs) $(DESTDIR)$(systemdsystemunitdir)/dbus.target.wants
    ln -fs ../dbus.socket
$(DESTDIR)$(systemdsystemunitdir)/dbus.target.wants/dbus.socket
# Unconditionally enable D-Bus on systemd installations
    $(mkinstalldirs) $(DESTDIR)$(systemdsystemunitdir)/sockets.target.wants
    ln -fs ../dbus.socket
$(DESTDIR)$(systemdsystemunitdir)/sockets.target.wants/dbus.socket
    $(mkinstalldirs)
$(DESTDIR)$(systemdsystemunitdir)/multi-user.target.wants
    ln -fs ../dbus.service
$(DESTDIR)$(systemdsystemunitdir)/multi-user.target.wants/dbus.service
endif
...



Kind Regards,
Hyungjun.