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
