node device driver names the HBA like "scsi_host5", but storage
driver uses "host5", which could make the user confused. This
changes them to be consistent. However, for back-compat reason,
adapter name like "host5" is still supported.
This introduces 4 new attributes for storage pool source adapter.
E.g.
<adapter type='fc_host' parent='scsi_host5' wwnn='20000000c9831b4b' wwpn='10000000c9831b4b'/>
Attribute 'type' can be either 'scsi_host' or 'fc_host', and defaults
to 'scsi_host' if attribute 'name' is specified. I.e. It's optional
for 'scsi_host' adapter, for back-compat reason. However, mandatory
for 'fc_host' adapter and any new future adapter types. Attribute
'parent' is to specify the parent for the fc_host adapter.
* docs/formatstorage.html.in:
- Add documents for the 4 new attrs
* docs/schemas/storagepool.rng:
- Add RNG schema
* src/conf/storage_conf.c:
- Parse and format the new XMLs
* src/conf/storage_conf.h:
- New struct virStoragePoolSourceAdapter, replace "char *adapter" with it;
- New enum virStoragePoolSourceAdapterType
* src/libvirt_private.syms:
- Export TypeToString and TypeFromString
* src/phyp/phyp_driver.c:
- Replace "adapter" with "adapter.data.name", which is member of the union
of the new struct virStoragePoolSourceAdapter now. Later patch will
add the checking, as "adapter.data.name" is only valid for "scsi_host"
adapter.
* src/storage/storage_backend_scsi.c:
- Like above
* tests/storagepoolxml2xmlin/pool-scsi-type-scsi-host.xml:
* tests/storagepoolxml2xmlin/pool-scsi-type-fc-host.xml:
- New test for 'fc_host' and "scsi_host" adapter
* tests/storagepoolxml2xmlout/pool-scsi.xml:
- Change the expected output, as the 'type' defaults to 'scsi_host' if 'name"
specified now
* tests/storagepoolxml2xmlout/pool-scsi-type-scsi-host.xml:
* tests/storagepoolxml2xmlout/pool-scsi-type-fc-host.xml:
- New test
* tests/storagepoolxml2xmltest.c:
- Include the test
To avoid
virportallocatortest.c: In function 'bind':
virportallocatortest.c:34:33: warning: cast increases required alignment of target type [-Wcast-align]
struct sockaddr_in *saddr = (struct sockaddr_in *)addr;
^
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
There are a number of places which generate cast alignment
warnings, which are difficult or impossible to address. Use
pragmas to disable the warnings in these few places
conf/nwfilter_conf.c: In function 'virNWFilterRuleDetailsParse':
conf/nwfilter_conf.c:1806:16: warning: cast increases required alignment of target type [-Wcast-align]
item = (nwItemDesc *)((char *)nwf + att[idx].dataIdx);
conf/nwfilter_conf.c: In function 'virNWFilterRuleDefDetailsFormat':
conf/nwfilter_conf.c:3238:16: warning: cast increases required alignment of target type [-Wcast-align]
item = (nwItemDesc *)((char *)def + att[i].dataIdx);
storage/storage_backend_mpath.c: In function 'virStorageBackendCreateVols':
storage/storage_backend_mpath.c:247:17: warning: cast increases required alignment of target type [-Wcast-align]
names = (struct dm_names *)(((char *)names) + next);
nwfilter/nwfilter_dhcpsnoop.c: In function 'virNWFilterSnoopDHCPDecode':
nwfilter/nwfilter_dhcpsnoop.c:994:15: warning: cast increases required alignment of target type [-Wcast-align]
pip = (struct iphdr *) pep->eh_data;
nwfilter/nwfilter_dhcpsnoop.c:1004:11: warning: cast increases required alignment of target type [-Wcast-align]
pup = (struct udphdr *) ((char *) pip + (pip->ihl << 2));
nwfilter/nwfilter_learnipaddr.c: In function 'procDHCPOpts':
nwfilter/nwfilter_learnipaddr.c:327:33: warning: cast increases required alignment of target type [-Wcast-align]
uint32_t *tmp = (uint32_t *)&dhcpopt->value;
nwfilter/nwfilter_learnipaddr.c: In function 'learnIPAddressThread':
nwfilter/nwfilter_learnipaddr.c:501:43: warning: cast increases required alignment of target type [-Wcast-align]
struct iphdr *iphdr = (struct iphdr*)(packet +
nwfilter/nwfilter_learnipaddr.c:538:43: warning: cast increases required alignment of target type [-Wcast-align]
struct iphdr *iphdr = (struct iphdr*)(packet +
nwfilter/nwfilter_learnipaddr.c:544:48: warning: cast increases required alignment of target type [-Wcast-align]
struct udphdr *udphdr= (struct udphdr *)
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
When reading the inotify FD, we get back a sequence of
struct inotify_event, each with variable length data following.
It is not safe to simply cast from the char *buf to the
struct inotify_event struct since this may violate data
alignment rules. Thus we must copy from the char *buf
into the struct inotify_event instance before accessing
the data.
uml/uml_driver.c: In function 'umlInotifyEvent':
uml/uml_driver.c:327:13: warning: cast increases required alignment of target type [-Wcast-align]
e = (struct inotify_event *)tmp;
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The current way virObject instances are allocated using
VIR_ALLOC_N causes alignment warnings
util/virobject.c: In function 'virObjectNew':
util/virobject.c:195:11: error: cast increases required alignment of target type [-Werror=cast-align]
Changing to use VIR_ALLOC_VAR will avoid the need todo
the casts entirely.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virNetlinkCommand() method takes an 'unsigned char **'
parameter to be filled with the received netlink message.
The callers then immediately cast this to 'struct nlmsghdr',
triggering (bogus) warnings about increasing alignment
requirements
util/virnetdev.c: In function 'virNetDevLinkDump':
util/virnetdev.c:1300:12: warning: cast increases required alignment of target type [-Wcast-align]
resp = (struct nlmsghdr *)*recvbuf;
^
util/virnetdev.c: In function 'virNetDevSetVfConfig':
util/virnetdev.c:1429:12: warning: cast increases required alignment of target type [-Wcast-align]
resp = (struct nlmsghdr *)recvbuf;
Since all callers cast to 'struct nlmsghdr' we can avoid
the warning problem entirely by simply changing the
signature of virNetlinkCommand to return a 'struct nlmsghdr **'
instead of 'unsigned char **'. The way we do the cast inside
virNetlinkCommand does not have any alignment issues.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Playing games with field offsets in a struct causes all sorts
of alignment warnings on ARM platforms
util/virkeycode.c: In function '__virKeycodeValueFromString':
util/virkeycode.c:26:7: warning: cast increases required alignment of target type [-Wcast-align]
(*(typeof(field_type) *)((char *)(object) + field_offset))
^
util/virkeycode.c:91:28: note: in expansion of macro 'getfield'
const char *name = getfield(virKeycodes + i, const char *, name_offset);
^
util/virkeycode.c:26:7: warning: cast increases required alignment of target type [-Wcast-align]
(*(typeof(field_type) *)((char *)(object) + field_offset))
^
util/virkeycode.c:94:20: note: in expansion of macro 'getfield'
return getfield(virKeycodes + i, unsigned short, code_offset);
^
util/virkeycode.c: In function '__virKeycodeValueTranslate':
util/virkeycode.c:26:7: warning: cast increases required alignment of target type [-Wcast-align]
(*(typeof(field_type) *)((char *)(object) + field_offset))
^
util/virkeycode.c:127:13: note: in expansion of macro 'getfield'
if (getfield(virKeycodes + i, unsigned short, from_offset) == key_value)
^
util/virkeycode.c:26:7: warning: cast increases required alignment of target type [-Wcast-align]
(*(typeof(field_type) *)((char *)(object) + field_offset))
^
util/virkeycode.c:128:20: note: in expansion of macro 'getfield'
return getfield(virKeycodes + i, unsigned short, to_offset);
There is no compelling reason to use a struct for the keycode
tables. It can easily just use an array of arrays instead,
avoiding all alignment problems
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
For both "live" and "config" changes of vcpupin and emulatorpin, an
all clear bitmap doesn't make sense, and it can just cause corruptions.
E.g (similar for emulatorpin).
% virsh vcpupin hame 0 8,^8 --config
% virsh vcpupin hame
VCPU: CPU Affinity
----------------------------------
0:
1: 0-63
2: 0-63
3: 0-63
% virsh dumpxml hame | grep cpuset
<vcpupin vcpu='0' cpuset=''/>
% virsh start hame
error: Failed to start domain hame
error: An error occurred, but the cause is unknown
This introduce a new attribute "num_queues" (same with the good name
QEMU uses) for virtio-scsi controller. An example of the XML:
<controller type='scsi' index='0' model='virtio-scsi' num_queues='8'/>
The corresponding QEMU command line:
-device virtio-scsi-pci,id=scsi0,num_queues=8,bus=pci.0,addr=0x3 \
By default, libtool builds two .o files for every .lo rule:
src/foo.o - static builds
src/.libs/foo.o - shared library builds
But since commit ad42b34b disabled static builds, src/foo.o is
no longer built by default. On a fresh checkout, this means our
protocol check rules using pdwtags were testing a missing file,
and thanks to a lousy behavior of pdwtags happily giving no output
and 0 exit status (http://bugzilla.redhat.com/949034), we were
merely claiming that "dwarves is too old" and skipping the test.
However, if you swap between branches and do incremental builds,
such as building v0.10.2-maint and then switching back to master,
you end up with src/foo.o being leftover from its 0.10.2 state,
and then 'make check' fails because the .o file does not match
the protocol-structs file due to API additions in the meantime.
A simpler fix would be to always look in .libs for the .o to
be parsed; but since it is possible to pass ./configure options
to tell libtool to do a static-only build with no shared .o,
I went with the approach of finding the newest of the two files,
whenever both exist.
* src/Makefile.am (PDWTAGS): Ensure we test just-built file.
Newer pod (hello rawhide) complains if you attempt to mix bullets
and non-bullets in the same list:
virsh.pod around line 3177: Expected text after =item, not a bullet
As our intent was to nest an inner list, we make that explicit to
keep pod happy.
* tools/virsh.pod (ENVIRONMENT): Use correct pod syntax.
When setting processor count for a domain using the API libvirt enforced
a maximum processor count, while it isn't enforced when taking the XML path.
This patch removes the check to match the XML.
Currently when getting an instance of virCgroupPtr we will
create the path in all cgroup controllers. Only at the virt
driver layer are we attempting to filter controllers. This
is bad because the mere act of creating the dirs in the
controllers can have a functional impact on the kernel,
particularly for performance.
Update the virCgroupForDriver() method to accept a bitmask
of controllers to use. Only create dirs in the controllers
that are requested. When creating cgroups for domains,
respect the active controller list from the parent cgroup
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virCgroupGetAppRoot is not clear in its meaning. Change
to virCgroupForSelf to highlight that this returns the
cgroup config for the caller's process
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The linker will ignore LD_PRELOAD libraries which do not
exist, just printing a warning message. This is not helpful
for the test suite which will be utterly fubar without the
preload library present. Add an explicit test for existence
of the library to protect against this
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Split the "resource" define out into multiple smaller
defines, one for each type of resource tuning parameter.
This makes the schema a bit clearer to read
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The last Viktor's effort to fix the race and memory corruption unfortunately
wasn't complete in the case the close callback was not registered in an
connection. At that time, the trail of event's that I'll describe later could
still happen and corrupt the memory or cause a crash of the client (including
the daemon in case of a p2p migration).
Consider the following prerequisities and trail of events:
Let's have a remote connection to a hypervisor that doesn't have a close
callback registered and the client is using the event loop. The crash happens in
cooperation of 2 threads. Thread E is the event loop and thread W is the worker
that does some stuff. R denotes the remote client.
1.) W - The client finishes everything and sheds the last reference on the client
2.) W - The virObject stuff invokes virConnectDispose that invokes doRemoteClose
3.) W - the remote close method invokes the REMOTE_PROC_CLOSE RPC method.
4.) W - The thread is preempted at this point.
5.) R - The remote side receives the close and closes the socket.
6.) E - poll() wakes up due to the closed socket and invokes the close callback
7.) E - The event loop is preempted right before remoteClientCloseFunc is called
8.) W - The worker now finishes, and frees the conn object.
9.) E - The remoteClientCloseFunc accesses the now-freed conn object in the
attempt to retrieve pointer for the real close callback.
10.) Kaboom, corrupted memory/segfault.
This patch tries to fix this by introducing a new object that survives the
freeing of the connection object. We can't increase the reference count on the
connection object itself or the connection would never be closed, as the
connection is closed only when the reference count reaches zero.
The new object - virConnectCloseCallbackData - is a lockable object that keeps
the pointers to the real user registered callback and ensures that the
connection callback is either not called if the connection was already freed or
that the connection isn't freed while this is being called.
This patch improves the error message after disconnecting from the
hypervisor and adds the close callback operations required not to leak
the callback reference.
The function is used to establish connection so it should be in the main
virsh file. This movement also enables further improvements done in next
patches.
Note that the "connect" command has moved from the host section of virsh to the
main section. It is now listed by 'virsh help virsh' instead of 'virsh help
host'.
Before closing the connection we unregister the close callback
to prevent a reference leak.
Further, the messages on virConnectClose != 0 are a bit more specific
now.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
By adjusting the reference count of the connection object we
prevent races between callback function and virConnectClose.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
This patch refactors various places to allow removing of the
defaultConsoleTargetType callback from the virCaps structure.
A new console character device target type is introduced -
VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_NONE - to mark that no type was
specified in the XML. This type is at the end converted to the standard
VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_SERIAL. Other types that are
different from this default have to be processed separately in the
device post parse callback.
Use the virDomainXMLConf structure to hold this data and tweak the code
to avoid semantic change.
Without configuration the KVM mac prefix is used by default. I chose it
as it's in the privately administered segment so it should be usable for
any purposes.
Use the qemu specific callback to fill this data in the qemu driver as
it's the only place where it was used and fix tests as the qemu test
capability object didn't configure the defaults for the tests.
This patch removes the emulatorRequired field and associated
infrastructure from the virCaps object. Instead the driver specific
callbacks are used as this field isn't enforced by all drivers.
This patch implements the appropriate callbacks in the qemu and lxc
driver and moves to check to that location.
This patch removes the defaultDiskDriverName from the virCaps
structure. This particular default value is used only in the qemu driver
so this patch uses the recently added callback to fill the driver name
if it's needed instead of propagating it through virCaps.
This gets rid of the parameter in favor of using the new callback
infrastructure to do the same stuff.
This patch implements the domain adjustment callback in the openVZ
driver and moves the check from the parser to a new validation method in
the callback infrastructure.
This patch implements the devices post parse callback and uses it to fill
the default qemu network card model into the XML if none is specified.
Libvirt assumes that the network card model for qemu is the "rtl8139".
Record this in the XML using the new callback to avoid user
confusion.
This patch adds instrumentation that will allow hypervisor drivers to
fill and validate domain and device definitions after parsed by the XML
parser.
With this patch, after the XML is parsed, a callback to the driver is
issued requesting to fill and validate driver specific details of the
configuration. This allows to use sensible defaults and checks on a per
driver basis at the time the XML is parsed.
Two callback pointers are stored in the new virDomainXMLConf object:
* virDomainDeviceDefPostParseCallback (devicesPostParseCallback)
- called for a single device parsed and for every single device in a
domain config. A virDomainDeviceDefPtr is passed along with the
domain definition and virCaps.
* virDomainDefPostParseCallback, (domainPostParseCallback)
- A callback that is meant to process the domain config after it's
parsed. A virDomainDefPtr is passed along with virCaps.
Both types of callbacks support arbitrary opaque data passed for the
callback functions.
Errors may be reported in those callbacks resulting in a XML parsing
failure.
This patch is the result of running:
for i in $(git ls-files | grep -v html | grep -v \.po$ ); do
sed -i -e "s/virDomainXMLConf/virDomainXMLOption/g" -e "s/xmlconf/xmlopt/g" $i
done
and a few manual tweaks.
If libnuma is not compiled in, or numa_available() returns an
error, stub out fake NUMA info consisting of one NUMA cell
containing all CPUs and memory.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Not all kernel builds have any entries under the location
/sys/devices/system/cpu/cpu0/topology. We already cope with
that being missing in some cases, but not all. Update the
code which looks for thread_siblings to cope with the missing
file
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The Raspberry Pi runs the armv6l architecture and apparently
people are trying to run libvirt LXC on it. So we should allow
that as a valid arch
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Implement the bare minimal sysinfo for ARM platforms by
reading the CPU models from /proc/cpuinfo
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Certain functions in the sysinfotest.c are not used unless
a whitelisted architecture is being built. Disable those
functions unless required to avoid warnings about unused
functions.
sysinfotest.c:93:1: warning: 'sysinfotest_run' defined but not used [-Wunused-function]
sysinfotest_run(const char *test,
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The nodedev driver currently only detects harddisk, cdrom
and floppy devices. This adds support for SD cards, which
are common storage for ARM devices, eg the Google ChromeBook
<device>
<name>block_mmcblk0_0xb1c7c08b</name>
<parent>computer</parent>
<capability type='storage'>
<block>/dev/mmcblk0</block>
<drive_type>sd</drive_type>
<serial>0xb1c7c08b</serial>
<size>15758000128</size>
<logical_block_size>512</logical_block_size>
<num_blocks>30777344</num_blocks>
</capability>
</device>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This reverts commit c9c87376f2.
Now that we force all containers to have a root filesystem,
there is no way the host's /dev is ever exposed
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently the LXC container code has two codepaths, depending on
whether there is a <filesystem> element with a target path of '/'.
If we automatically add a <filesystem> device with src=/ and dst=/,
for any container which has not specified a root filesystem, then
we only need one codepath for setting up the filesystem.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Early on kernel support for private devpts was not widespread,
so we had compatibiltiy codepaths. Such old kernels are not
seriously used for LXC these days, so the compat code can go
away
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
When creating a logical volume with virStorageVolCreateXMLFrom,
"qemu-img convert" is called internally if clonevol is a file volume.
Then, vol->target.format is used as output_fmt parameter but the
target.format of logical volumes is always 0 because logical volumes
haven't the volume format type element.
Fortunately, 0 was treated as RAW file format before commit f772b3d9,
so there was no problem. But now, 0 is treated as the type of none,
qemu-img fails with "Unknown file format 'none'".
This patch fixes this issue by treating output block devices as RAW
file format like for input block devices.
Signed-off-by: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
otherwise we crash later on if we don't find a match like:
#0 0xb72c2b4f in virSecurityManagerGenLabel (mgr=0xb8e42d20, vm=0xb8ef40c0) at security/security_manager.c:424
#1 0xb18811f3 in qemuProcessStart (conn=conn@entry=0xb8eed880, driver=driver@entry=0xb8e3b1e0, vm=vm@entry=0xb8ef58f0,
migrateFrom=migrateFrom@entry=0xb18f6088 "stdio", stdin_fd=18,
stdin_path=stdin_path@entry=0xb8ea7798 "/var/lib/jenkins/jobs/libvirt-tck-build/workspace/tck.img", snapshot=snapshot@entry=0x0,
vmop=vmop@entry=VIR_NETDEV_VPORT_PROFILE_OP_RESTORE, flags=flags@entry=2) at qemu/qemu_process.c:3364
#2 0xb18d6cb2 in qemuDomainSaveImageStartVM (conn=conn@entry=0xb8eed880, driver=driver@entry=0xb8e3b1e0, vm=0xb8ef58f0, fd=fd@entry=0xb6bf3f98,
header=header@entry=0xb6bf3fa0, path=path@entry=0xb8ea7798 "/var/lib/jenkins/jobs/libvirt-tck-build/workspace/tck.img",
start_paused=start_paused@entry=false) at qemu/qemu_driver.c:4843
#3 0xb18d7eeb in qemuDomainRestoreFlags (conn=conn@entry=0xb8eed880,
path=path@entry=0xb8ea7798 "/var/lib/jenkins/jobs/libvirt-tck-build/workspace/tck.img", dxml=dxml@entry=0x0, flags=flags@entry=0)
at qemu/qemu_driver.c:4962
#4 0xb18d8123 in qemuDomainRestore (conn=0xb8eed880, path=0xb8ea7798 "/var/lib/jenkins/jobs/libvirt-tck-build/workspace/tck.img")
at qemu/qemu_driver.c:4987
#5 0xb718d186 in virDomainRestore (conn=0xb8eed880, from=0xb8ea87d8 "/var/lib/jenkins/jobs/libvirt-tck-build/workspace/tck.img") at libvirt.c:2768
#6 0xb7736363 in remoteDispatchDomainRestore (args=<optimized out>, rerr=0xb6bf41f0, client=0xb8eedaf0, server=<optimized out>, msg=<optimized out>)
at remote_dispatch.h:4679
#7 remoteDispatchDomainRestoreHelper (server=0xb8e1a3e0, client=0xb8eedaf0, msg=0xb8ee72c8, rerr=0xb6bf41f0, args=0xb8ea8968, ret=0xb8ef5330)
at remote_dispatch.h:4661
#8 0xb720db01 in virNetServerProgramDispatchCall (msg=0xb8ee72c8, client=0xb8eedaf0, server=0xb8e1a3e0, prog=0xb8e216b0)
at rpc/virnetserverprogram.c:439
#9 virNetServerProgramDispatch (prog=0xb8e216b0, server=server@entry=0xb8e1a3e0, client=0xb8eedaf0, msg=0xb8ee72c8) at rpc/virnetserverprogram.c:305
#10 0xb7206e97 in virNetServerProcessMsg (msg=<optimized out>, prog=<optimized out>, client=<optimized out>, srv=0xb8e1a3e0) at rpc/virnetserver.c:162
#11 virNetServerHandleJob (jobOpaque=0xb8ea7720, opaque=0xb8e1a3e0) at rpc/virnetserver.c:183
#12 0xb70f9f78 in virThreadPoolWorker (opaque=opaque@entry=0xb8e1a540) at util/virthreadpool.c:144
#13 0xb70f94a5 in virThreadHelper (data=0xb8e0e558) at util/virthreadpthread.c:161
#14 0xb705d954 in start_thread (arg=0xb6bf4b70) at pthread_create.c:304
#15 0xb6fd595e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
This unbreaks libvirt-tck's domain/100-transient-save-restore.t with
qemu:///session and selinux compiled in but disabled.
Introduced by 8d68cbeaa8
Commit f84b92ea introduced a memory leak on error; John Ferlan reported
that valgrind caught it during 'make check'.
* src/qemu/qemu_command.c (qemuBuildMachineArgStr): Plug leak.
By passing the flags -z relro -z now to the linker, we can force
it to resolve all library symbols at startup, instead of on-demand.
This allows it to then make the global offset table (GOT) read-only,
which makes some security attacks harder.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
PIE (position independent executable) adds security to executables
by composing them entirely of position-independent code (PIC. The
.so libraries already build with -fPIC. This adds -fPIE which is
the equivalent to -fPIC, but for executables. This for allows Exec
Shield to use address space layout randomization to prevent attackers
from knowing where existing executable code is during a security
attack using exploits that rely on knowing the offset of the
executable code in the binary, such as return-to-libc attacks.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
