xen: fix memory corruption in legacy driver

Commit 632180d1 introduced memory corruption in xenDaemonListDefinedDomains
by starting to populate the names array at index -1, causing all sorts
of havoc in libvirtd such as aborts like the following

*** Error in `/usr/sbin/libvirtd': double free or corruption (out): 0x00007fffe00ccf20 ***
======= Backtrace: =========
/lib64/libc.so.6(+0x7abf6)[0x7ffff3fa0bf6]
/lib64/libc.so.6(+0x7b973)[0x7ffff3fa1973]
/lib64/libc.so.6(xdr_array+0xde)[0x7ffff403cbae]
/usr/sbin/libvirtd(+0x50251)[0x5555555a4251]
/lib64/libc.so.6(xdr_free+0x15)[0x7ffff403ccd5]
/usr/lib64/libvirt.so.0(+0x1fad34)[0x7ffff76b1d34]
/usr/lib64/libvirt.so.0(virNetServerProgramDispatch+0x1fc)[0x7ffff76b16f1]
/usr/lib64/libvirt.so.0(+0x1f214a)[0x7ffff76a914a]
/usr/lib64/libvirt.so.0(+0x1f222d)[0x7ffff76a922d]
/usr/lib64/libvirt.so.0(+0xbcc4f)[0x7ffff7573c4f]
/usr/lib64/libvirt.so.0(+0xbc5e5)[0x7ffff75735e5]
/lib64/libpthread.so.0(+0x7e0f)[0x7ffff48f7e0f]
/lib64/libc.so.6(clone+0x6d)[0x7ffff400e7dd]

Fix by initializing ret to 0 and only setting to error on failure path.
build: fix missing max_queued_clients in augeas test file for libvirtd.conf

Broken in commit 1199edb1d4e3ebbc691bd32d3519a3b662225420
qemu: enable auto-allocate of all PCI addresses

Previous refactoring of the guest PCI address reservation/allocation
code allowed for slot types other than basic PCI (e.g. PCI express,
non-hotpluggable slots, etc) but would not auto-allocate a slot for a
device that required any type other than a basic hot-pluggable
PCI slot.

This patch refactors the code to be aware of different slot types
during auto-allocation of addresses as well - as long as there is an
empty slot of the required type, it will be found and used.

The piece that *wasn't* added is that we don't auto-create a new PCI
bus when needed for anything except basic PCI devices. This is because
there are multiple different types of controllers that can provide,
for example, a PCI express slot (in addition to the pcie-root
controller, these can also be found on a "root-port" or on a
"downstream-switch-port"). Since we currently don't support any PCIe
devices (except pending support for dmi-to-pci-bridge), we can defer
any decision on what to do about this.
qemu: add pcie-root controller

This controller is implicit on q35 machinetypes. It provides 31 PCIe
(*not* PCI) slots as controller 0.

Currently there are no devices that can connect to pcie-root, and no
implicit pci controller on a q35 machine, so q35 is still
unusable. For a usable q35 system, we need to add a
"dmi-to-pci-bridge" pci controller, which can connect to pcie-root,
and provides standard pci slots that can be used to connect other
devices.
qemu: add dmi-to-pci-bridge controller

This PCI controller, named "dmi-to-pci-bridge" in the libvirt config,
and implemented with qemu's "i82801b11-bridge" device, connects to a
PCI Express slot (e.g. one of the slots provided by the pcie-root
controller, aka "pcie.0" on the qemu commandline), and provides 31
*non-hot-pluggable* PCI (*not* PCIe) slots, numbered 1-31.

Any time a machine is defined which has a pcie-root controller
(i.e. any q35-based machinetype), libvirt will automatically add a
dmi-to-pci-bridge controller if one doesn't exist, and also add a
pci-bridge controller. The reasoning here is that any useful domain
will have either an immediate (startup time) or eventual (subsequent
hot-plug) need for a standard PCI slot; since the pcie-root controller
only provides PCIe slots, we need to connect a dmi-to-pci-bridge
controller to it in order to get a non-hot-plug PCI slot that we can
then use to connect a pci-bridge - the slots provided by the
pci-bridge will be both standard PCI and hot-pluggable.

Since pci-bridge devices themselves can not be hot-plugged into a
running system (although you can hot-plug other devices into a
pci-bridge's slots), any new pci-bridge controller that is added can
(and will) be plugged into the dmi-to-pci-bridge as long as it has
empty slots available.

This patch is also changing the qemuxml2xml-pcie test from a "DO_TEST"
to a "DO_DIFFERENT_TEST". This is so that the "before" xml can omit
the automatically added dmi-to-pci-bridge and pci-bridge devices, and
the "after" xml can include it - this way we are testing if libvirt is
properly adding these devices.
qemu: fix handling of default/implicit devices for q35

This patch adds in special handling for a few devices that need to be
treated differently for q35 domains:

usb - there is no implicit/default usb controller for the q35
machinetype. This is done because normally the default usb controller
is added to a domain by just adding "-usb" to the qemu commandline,
and it's assumed that this will add a single piix3 usb1 controller at
slot 1 function 2. That's not what happens when the machinetype is
q35, though. Instead, adding -usb to the commandline adds 3 usb
(version 2) controllers to the domain at slot 0x1D.{1,2,7}. Rather
than having

  <controller type='usb' index='0'/>

translate into 3 separate devices on the PCI bus, it's cleaner to not
automatically add a default usb device; one can always be added
explicitly if desired. Or we may decide that on q35 machines, 3 usb
controllers will be automatically added when none is given. But for
this initial commit, at least we aren't locking ourselves into
something we later won't want.

video - qemu always initializes the primary video device immediately
after any integrated devices for the machinetype. Unless instructed
otherwise (by using "-device vga..." instead of "-vga" which libvirt
uses in many cases to work around deficiencies and bugs in various
qemu versions) qemu will always pick the first unused slot. In the
case of the "pc" machinetype and its derivatives, this is always slot
2, but on q35 machinetypes, the first free slot is slot 1 (since the
q35's integrated peripheral devices are placed in other slots,
e.g. slot 0x1f). In order to make the PCI address of the video device
predictable, that slot (1 or 2, depending on machinetype) is reserved
even when no video device has been specified.

sata - a q35 machine always has a sata controller implicitly added at
slot 0x1F, function 2. There is no way to avoid this controller, so we
always add it. Note that the xml2xml tests for the pcie-root and q35
cases were changed to use DO_TEST_DIFFERENT() so that we can check for
the sata controller being automatically added. This is especially
important because we can't check for it in the xml2argv output (it has
no effect on that output since it's an implicit device).

ide - q35 has no ide controllers.

isa and smbus controllers - these two are always present in a q35 (at
slot 0x1F functions 0 and 3) but we have no way of modelling them in
our config. We do need to reserve those functions so that the user
doesn't attempt to put anything else there though. (note that the "pc"
machine type also has an ISA controller, which we also ignore).
qemu: properly set/use device alias for pci controllers

We had been setting the device alias in the devinceinfo for pci
controllers to "pci%u", but then hardcoding "pci.%u" when creating the
device address for other devices using that pci bus. This all worked
just fine until we encountered the built-in "pcie.0" bus (the PCIe
root complex) in Q35 machines.

In order to create the correct commandline for this one case, this
patch:

1) sets the alias for PCI controllers correctly, to "pci.%u" (or
"pcie.%u" for the pcie-root controller)

2) eliminates the hardcoded "pci.%u" for pci controllers when
generatuing device address strings, and instead uses the controller's
alias.

3) plumbs a pointer to the virDomainDef all the way down to
qemuBuildDeviceAddressStr. This was necessary in order to make the
aliase of the controller *used by a device* available (previously
qemuBuildDeviceAddressStr only had the deviceinfo of the device
itself, *not* of the controller it was connecting to). This made for a
larger than desired diff, but at least in the future we won't have to
do it again, since all the information we could possibly ever need for
future enhancements is in the virDomainDef. (right?)

This should be done for *all* controllers, but for now we just do it
in the case of PCI controllers, to reduce the likelyhood of
regression.
qemu_migration: Don't error on tunelled migration with --copy-storage

https://bugzilla.redhat.com/show_bug.cgi?id=979477

Since 1.0.3 we are using the new way to copy non shared storage during
migration (the NBD way). However, whether the new or old way is used is
not controllable by user but unconditionally turned on if both sides of
migration support it. Moreover, the implementation is not complete: the
combination for VIR_MIGRATE_TUNNELLED flag is missing (as we need to
open new port on the destination) in which case we just error out. This
is a deadly combination: not letting users choose their destiny and
erroring out. We should not do that but VIR_WARN and turn the NBD off
instead.
qemu: enable using implicit sata controller in q35 machines

q35 machines have an implicit ahci (sata) controller at 00:1F.2 which
has no "id" associated with it. For this reason, we can't refer to it
as "ahci0". Instead, we don't give an id on the commandline, which
qemu interprets as "use the first ahci controller". We then need to
specify the unit with "unit=%d" rather than adding it onto the bus
arg.
qemu: improve error reporting during PCI address validation

This patch addresses two concerns with the error reporting when an
incompatible PCI address is specified for a device:

1) It wasn't always apparent which device had the problem. With this
patch applied, any error about an incompatible address will always
contain the full address as given in the config, so it will be easier
to determine which device's config aused the problem.

2) In some cases when the problem came from bad config, the error
message was erroneously classified as VIR_ERR_INTERNAL_ERROR. With
this patch applied, the same error message will be changed to indicate
either "internal" or "xml" error depending on whether the address came
from the config, or was automatically generated by libvirt.

Note that in the case of "internal" (due to bad auto-generation)
errors, the PCI address won't be of much use in finding the location
in config to change (because it was automatically generated). Of
course that makes perfect sense, but still the address could provide a
clue about a bug in libvirt attempting to use a type of pci bus that
doesn't have its flags set correctly (or something similar). In other
words, it's not perfect, but it is definitely better.
xen: Use internal interfaces in xenDomainUsedCpus

Since commit 95e18efd most public interfaces (xenUnified...) obtain
a virDomainDefPtr via xenGetDomainDefFor...() which take the unified
lock.
This is already taken before calling xenDomainUsedCpus(), so we get
a deadlock for active guests. Avoid this by splitting up
xenUnifiedDomainGetVcpusFlags() and xenUnifiedDomainGetVcpus() into
public and private function calls (which get the virDomainDefPtr passed)
and use those in xenDomainUsedCpus().

    xenDomainUsedCpus
      ...
      nb_vcpu = xenUnifiedDomainGetMaxVcpus(dom);
        return xenUnifiedDomainGetVcpusFlags(...)
          ...
          if (!(def = xenGetDomainDefForDom(dom)))
            return xenGetDomainDefForUUID(dom->conn, dom->uuid);
              ...
              ret = xenHypervisorLookupDomainByUUID(conn, uuid);
                ...
                xenUnifiedLock(priv);
                name = xenStoreDomainGetName(conn, id);
                xenUnifiedUnlock(priv);
      ...
      if ((ncpus = xenUnifiedDomainGetVcpus(dom, cpuinfo, nb_vcpu,
        ...
        if (!(def = xenGetDomainDefForDom(dom)))
          [again like above]

Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
build: fix configure detection of if_bridge.h on RHEL 6

A fresh checkout on a RHEL 6 machine with these packages:
kernel-headers-2.6.32-405.el6.x86_64
glibc-2.12-1.128.el6.x86_64
failed to configure with this message:
checking for linux/if_bridge.h... no
configure: error: You must install kernel-headers in order to compile libvirt with QEMU or LXC support

Digging in config.log, we see that the problem is identical to
what we fixed earlier in commit d12c2811:

configure:98831: checking for linux/if_bridge.h
configure:98853: gcc -std=gnu99 -c -g -O2  conftest.c >&5
In file included from /usr/include/linux/if_bridge.h:17,
                 from conftest.c:559:
/usr/include/linux/in6.h:31: error: redefinition of 'struct in6_addr'
/usr/include/linux/in6.h:48: error: redefinition of 'struct sockaddr_in6'
/usr/include/linux/in6.h:56: error: redefinition of 'struct ipv6_mreq'
configure:98860: $? = 1

I had not hit it earlier because I was using incremental builds,
where config.cache had shielded me from the kernel-headers breakage.

* configure.ac (if_bridge.h): Avoid conflicting type definitions.

Signed-off-by: Eric Blake <eblake@redhat.com>
virGetGroupList: always include the primary group

The change from initgroups to virGetGroupList/setgroups in
cab36cfe71ba83b71e536ba5c98e596f02b697b0 dropped the primary group from
processes group list iff the passed in group to virGetGroupList differs
from the user's primary group.

So always include the primary group to bring back the old behaviour.

Debian has the kvm group as primary group but uses
libvirt-qemu:libvirt-qemu as user:group to run the kvm process so
without this change the /dev/kvm is inaccessible.
nwfilter: Use -m conntrack rather than -m state

Since iptables version 1.4.16 '-m state --state NEW' is converted to
'-m conntrack --ctstate NEW'. Therefore, when encountering this or later
versions of iptables use '-m conntrack --ctstate'.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
conf: add startupPolicy attribute for harddisk

Add startupPolicy attribute for harddisk with type "file",
"block" and "dir". 'requisite' is not supported currently for
harddisk.
qemu: support to drop disk with 'optional' startupPolicy

Go through disks of guest, if one disk doesn't exist or its backing
chain is broken, with 'optional' startupPolicy, for CDROM and Floppy
we only discard its source path definition in xml, for disks we drop
it from disk list and free it.
Revert "build: fix configure detection of if_bridge.h on RHEL 6"

This reverts commit 2df8d99138dc8396c7d46c3cceca8ce2e93b605a.

The change breaks configure on any recent Fedora platform
Reverse logic allowing partial DHCP host XML

Before, missing attributes were only OK when adding entries;
modification and deletion required all of them.

Now, only deletion works with missing attributes, as long as
the host is uniquely identified.
maint: the compiler is not always named gcc

https://bugzilla.redhat.com/show_bug.cgi?id=994589 complained that
even when using a cross-compiler not named 'gcc', the configure
output confusingly referred to gcc.

* m4/virt-compile-warnings.m4 (LIBVIRT_COMPILE_WARNINGS): Use a
more generic statement in configure output.

Signed-off-by: Eric Blake <eblake@redhat.com>
maint: avoid C99 loop declaration

Commit 3d0e3c1 reintroduced a problem previously squelched in
commit 7e5aa78.  Add a syntax check this time around.

util/virutil.c: In function 'virGetGroupList':
util/virutil.c:1015: error: 'for' loop initial declaration used outside C99 mode

* cfg.mk (sc_prohibit_loop_var_decl): New rule.
* src/util/virutil.c (virGetGroupList): Fix offender.

Signed-off-by: Eric Blake <eblake@redhat.com>