This is required in case a lock manager needs to contact libvirtd in
case of an unexpected event.

https://www.gnu.org/licenses/gpl-howto.html recommends that
the 'If not, see <url>.' phrase be a separate sentence.

* tests/securityselinuxhelper.c: Remove doubled line.
* tests/securityselinuxtest.c: Likewise.
* globally: s/;  If/.  If/

Per the FSF address could be changed from time to time, and GNU
recommends the following now: (http://www.gnu.org/licenses/gpl-howto.html)

  You should have received a copy of the GNU General Public License
  along with Foobar.  If not, see <http://www.gnu.org/licenses/>.

This patch removes the explicit FSF address, and uses above instead
(of course, with inserting 'Lesser' before 'General').

Except a bunch of files for security driver, all others are changed
automatically, the copyright for securify files are not complete,
that's why to do it manually:

  src/security/security_selinux.h
  src/security/security_driver.h
  src/security/security_selinux.c
  src/security/security_apparmor.h
  src/security/security_apparmor.c
  src/security/security_driver.c

Allow a 'configFile' parameter to be passed into the lock
drivers to provide configuration. Wire up the QEMU driver
to pass in file names '/etc/libvirt/qemu-$NAME.conf
eg qemu-sanlock.conf

* src/locking/lock_driver.h, src/locking/lock_driver_nop.c,
  src/locking/lock_driver_sanlock.c, src/locking/lock_manager.c,
  src/locking/lock_manager.h: Add configFile parameter
* src/qemu/qemu_conf.c: Pass in configuration file path to
  lock driver plugins

The libvirt sanlock plugin is intentionally leaking a file
descriptor to QEMU. To enable QEMU to use this FD under
SELinux, it must be labelled correctly. We dont want to use
the svirt_image_t for this, since QEMU must not be allowed
to actually use the FD. So instead we label it with svirt_t
using virSecurityManagerSetProcessFDLabel

* src/locking/domain_lock.c, src/locking/domain_lock.h,
  src/locking/lock_driver.h, src/locking/lock_driver_nop.c,
  src/locking/lock_driver_sanlock.c, src/locking/lock_manager.c,
  src/locking/lock_manager.h: Optionally pass an FD back to
  the hypervisor for security driver labelling
* src/qemu/qemu_process.c: label the lock manager plugin
  FD with the process label

In between fork and exec, a connection to sanlock is acquired
and the socket file descriptor is intionally leaked to the
child process. sanlock watches this FD for POLL_HANGUP to
detect when QEMU has exited. We don't want a rogus/compromised
QEMU from issuing sanlock RPC calls on the leaked FD though,
since that could be used to DOS other guests. By calling
sanlock_restrict() on the socket before exec() we can lock
it down.

* configure.ac: Check for sanlock_restrict API
* src/locking/domain_lock.c: Restrict lock acquired in
  process startup phase
* src/locking/lock_driver.h: Add VIR_LOCK_MANAGER_ACQUIRE_RESTRICT
* src/locking/lock_driver_sanlock.c: Add call to sanlock_restrict
  when requested by VIR_LOCK_MANAGER_ACQUIRE_RESTRICT flag

Define the basic framework lock manager plugins. The
basic plugin API for 3rd parties to implemented is
defined in

  src/locking/lock_driver.h

This allows dlopen()able modules for alternative locking
schemes, however, we do not install the header. This
requires lock plugins to be in-tree allowing changing of
the lock manager plugin API in future.

The libvirt code for loading & calling into plugins
is in

  src/locking/lock_manager.{c,h}

* include/libvirt/virterror.h, src/util/virterror.c: Add
  VIR_FROM_LOCKING
* src/locking/lock_driver.h: API for lock driver plugins
  to implement
* src/locking/lock_manager.c, src/locking/lock_manager.h:
  Internal API for managing locking
* src/Makefile.am: Add locking code