5e5acbc8d6
Setting unix_sock_group to something else than default "root" in /etc/libvirt/libvirtd.conf prevents system libvirtd from dumping core on crash. This is because we used setgid(unix_sock_group) before binding to /var/run/libvirt/libvirt-sock* and setgid() back to original group. However, if a process changes its effective or filesystem group ID, it will be forbidden from leaving core dumps unless fs.suid_dumpable sysctl is set to something else then 0 (and it is 0 by default). Changing socket's group ownership after bind works better. And we can do so without introducing a race condition since we loosen access rights by changing the group from root to something else.
LibVirt : simple API for virtualization
Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.
Daniel Veillard <veillard@redhat.com>