In case libvirtd is asked to unplug a device but the device is actually
unplugged later when libvirtd is not running, we need to detect that and
remove such device when libvirtd starts again and reconnects to running
domains.

This API provides a NULL-terminated list of devices which are currently
attached to a QEMU domain.

Make virStringArrayHasString return false when called on a non-existent
string array.

Attempts to start a domain with both SELinux and DAC security
modules loaded will deadlock; latent problem introduced in commit
fdb3bde3 and exposed in commit 29fe5d74.  Basically, when recursing
into the security manager for other driver's prefork, we have to
undo the asymmetric lock taken at the manager level.

Reported by Jiri Denemark, with diagnosis help from Dan Berrange.

* src/security/security_stack.c (virSecurityStackPreFork): Undo
extra lock grabbed during recursion.
Signed-off-by: NEric Blake <eblake@redhat.com>

Makefiles are another easy file to enforce line limits.

Mostly straightforward; interesting tricks worth noting:
src/Makefile.am: $(confdir) was already defined, use it in more places
tests/Makefile.am: path_add and VG required some interesting compression

* cfg.mk (sc_prohibit_long_lines): Add another test.
* Makefile.am: Fix offenders.
* daemon/Makefile.am: Likewise.
* docs/Makefile.am: Likewise.
* python/Makefile.am: Likewise.
* src/Makefile.am: Likewise.
* tests/Makefile.am: Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

Commit 75c12564 states that virGetGroupList must not be called
between fork and exec, then commit ee777e99 promptly violated
that for lxc's use of virSecurityManagerSetProcessLabel.  Hoist
the supplemental group detection to the time that the security
manager needs to fork.  Qemu is safe, as it uses
virSecurityManagerSetChildProcessLabel which in turn uses
virCommand to determine supplemental groups.

This does not fix the fact that virSecurityManagerSetProcessLabel
calls virSecurityDACParseIds calls parseIds which eventually
calls getpwnam_r, which also violates fork/exec async-signal-safe
safety rules, but so far no one has complained of hitting
deadlock in that case.

* src/security/security_dac.c (_virSecurityDACData): Track groups
in private data.
(virSecurityDACPreFork): New function, to set them.
(virSecurityDACClose): Clean up new fields.
(virSecurityDACGetIds): Alter signature.
(virSecurityDACSetSecurityHostdevLabelHelper)
(virSecurityDACSetChardevLabel, virSecurityDACSetProcessLabel)
(virSecurityDACSetChildProcessLabel): Update callers.
Signed-off-by: NEric Blake <eblake@redhat.com>

A future patch wants the DAC security manager to be able to safely
get the supplemental group list for a given uid, but at the time
of a fork rather than during initialization so as to pick up on
live changes to the system's group database.  This patch adds the
framework, including the possibility of a pre-fork callback
failing.

For now, any driver that implements a prefork callback must be
robust against the possibility of being part of a security stack
where a later element in the chain fails prefork.  This means
that drivers cannot do any action that requires a call to postfork
for proper cleanup (no grabbing a mutex, for example).  If this
is too prohibitive in the future, we would have to switch to a
transactioning sequence, where each driver has (up to) 3 callbacks:
PreForkPrepare, PreForkCommit, and PreForkAbort, to either clean
up or commit changes made during prepare.

* src/security/security_driver.h (virSecurityDriverPreFork): New
callback.
* src/security/security_manager.h (virSecurityManagerPreFork):
Change signature.
* src/security/security_manager.c (virSecurityManagerPreFork):
Optionally call into driver, and allow returning failure.
* src/security/security_stack.c (virSecurityDriverStack):
Wrap the handler for the stack driver.
* src/qemu/qemu_process.c (qemuProcessStart): Adjust caller.
Signed-off-by: NEric Blake <eblake@redhat.com>

When either "cpuset" of <vcpu> is specified, or the "placement" of
<vcpu> is "auto", only setting the cpuset.mems might cause the guest
starting to fail. E.g. ("placement" of both <vcpu> and <numatune> is
"auto"):

1) Related XMLs
  <vcpu placement='auto'>4</vcpu>
  <numatune>
    <memory mode='strict' placement='auto'/>
  </numatune>

2) Host NUMA topology
  % numactl --hardware
  available: 8 nodes (0-7)
  node 0 cpus: 0 4 8 12 16 20 24 28
  node 0 size: 16374 MB
  node 0 free: 11899 MB
  node 1 cpus: 32 36 40 44 48 52 56 60
  node 1 size: 16384 MB
  node 1 free: 15318 MB
  node 2 cpus: 2 6 10 14 18 22 26 30
  node 2 size: 16384 MB
  node 2 free: 15766 MB
  node 3 cpus: 34 38 42 46 50 54 58 62
  node 3 size: 16384 MB
  node 3 free: 15347 MB
  node 4 cpus: 3 7 11 15 19 23 27 31
  node 4 size: 16384 MB
  node 4 free: 15041 MB
  node 5 cpus: 35 39 43 47 51 55 59 63
  node 5 size: 16384 MB
  node 5 free: 15202 MB
  node 6 cpus: 1 5 9 13 17 21 25 29
  node 6 size: 16384 MB
  node 6 free: 15197 MB
  node 7 cpus: 33 37 41 45 49 53 57 61
  node 7 size: 16368 MB
  node 7 free: 15669 MB

4) cpuset.cpus will be set as: (from debug log)

2013-05-09 16:50:17.296+0000: 417: debug : virCgroupSetValueStr:331 :
Set value '/sys/fs/cgroup/cpuset/libvirt/qemu/toy/cpuset.cpus'
to '0-63'

5) The advisory nodeset got from querying numad (from debug log)

2013-05-09 16:50:17.295+0000: 417: debug : qemuProcessStart:3614 :
Nodeset returned from numad: 1

6) cpuset.mems will be set as: (from debug log)

2013-05-09 16:50:17.296+0000: 417: debug : virCgroupSetValueStr:331 :
Set value '/sys/fs/cgroup/cpuset/libvirt/qemu/toy/cpuset.mems'
to '0-7'

I.E, the domain process's memory is restricted on the first NUMA node,
however, it can use all of the CPUs, which will likely cause the domain
process to fail to start because of the kernel fails to allocate
memory with the the memory policy as "strict".

% tail -n 20 /var/log/libvirt/qemu/toy.log
...
2013-05-09 05:53:32.972+0000: 7318: debug : virCommandHandshakeChild:377 :
Handshake with parent is done
char device redirected to /dev/pts/2 (label charserial0)
kvm_init_vcpu failed: Cannot allocate memory
...
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

These helpers use the remembered host capabilities to retrieve the cpu
map rather than query the host again. The intended usage for this
helpers is to fix automatic NUMA placement with strict memory alloc. The
code doing the prepare needs to pin the emulator process only to cpus
belonging to a subset of NUMA nodes of the host.

When user does not specify any model for scsi controller, or worse, no
controller at all, but libvirt automatically adds scsi controller with
no model, we are not searching for virtio-scsi and thus this can fail
for example on qemu which doesn't support lsi logic adapter.

This means that when qemu on x86 doesn't support lsi53c895a and the
user adds the following to an XML without any scsi controller:

<disk ...>
  ...
  <target dev='sda'>
</disk>

libvirt fails like this:
 # virsh define asdf.xml
 error: Failed to define domain from asdf.xml
 error: internal error Unable to determine model for scsi controller

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=974943

Similarly to qemu driver, we can use a helper function to
lookup a domain instead of copying multiple lines around.

With the majority of fields in the virLXCDriverPtr struct
now immutable or self-locking, there is no need for practically
any methods to be using the LXC driver lock. Only a handful
of helper APIs now need it.

The activeUsbHostdevs item in LXCDriver are lockable, but the lock has
to be called explicitly. Call the virObject(Un)Lock() in order to
achieve mutual exclusion once lxcDriverLock is removed.

The 'driver->caps' pointer can be changed on the fly. Accessing
it currently requires the global driver lock. Isolate this
access in a single helper, so a future patch can relax the
locking constraints.

Annotate the fields in virLXCDriverPtr to indicate the locking
rules for their use.

Currently the virLXCDriverPtr struct contains an wide variety
of data with varying access needs. Move all the static config
data into a dedicated virLXCDriverConfigPtr object. The only
locking requirement is to hold the driver lock, while obtaining
an instance of virLXCDriverConfigPtr. Once a reference is held
on the config object, it can be used completely lockless since
it is immutable.

NB, not all APIs correctly hold the driver lock while getting
a reference to the config object in this patch. This is safe
for now since the config is never updated on the fly. Later
patches will address this fully.

It is not used anywhere, so it makes no sense to have it there.

Moreover, since virAsprintf now does report OOM error, there's no need
to call virReportOOMError in error path.

When virAsprintf was changed from a function to a macro
reporting OOM error in dc6f2dad, it was documented as returning
0 on success. This is incorrect, it returns the number of bytes
written as asprintf does.

Some of the functions were converted to use virAsprintf's return
value directly, changing the return value on success from 0 to >= 0.

For most of these, this is not a problem, but the change in
virPCIDriverDir breaks PCI passthrough.

The return value check in virhashtest pre-dates virAsprintf OOM
conversion.

vmwareMakePath seems to be unused.

Merge the virCommandPreserveFD / virCommandTransferFD methods
into a single virCommandPasFD method, and use a new
VIR_COMMAND_PASS_FD_CLOSE_PARENT to indicate their difference
in behaviour
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Wire up the new virDomainCreate{XML}WithFiles methods in the
LXC driver, so that FDs get passed down to the init process.

The lxc_container code needs to do a little dance in order
to renumber the file descriptors it receives into linear
order, starting from STDERR_FILENO + 1.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

In the following commit:

  commit 03d813bb
  Author: Marek Marczykowski <marmarek@invisiblethingslab.com>
  Date:   Thu May 23 02:01:30 2013 +0200

    remote: fix dom->id after virDomainCreateWithFlags

The virDomainCreateWithFlags remote client helper was made to
invoke REMOTE_PROC_DOMAIN_LOOKUP_BY_UUID to refresh the 'id'
of the domain, following the pattern used in the previous
virDomainCreate method impl.

The remote protocol for virDomainCreateWithFlags though did
actually fix the design flaw in virDomainCreate, by directly
returning the new domain info. For some reason, this data was
never used. So we can just use that data now instead.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Since they make use of file descriptor passing, the remote protocol
methods for virDomainCreate{XML}WithFiles must be written by hand.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

With container based virt, it is useful to be able to pass
pre-opened file descriptors to the container init process.
This allows for containers to be auto-activated from incoming
socket connections, passing the active socket into the container.

To do this, introduce a pair of new APIs, virDomainCreateXMLWithFiles
and virDomainCreateWithFiles, which accept an array of file
descriptors. For the LXC driver, UNIX file descriptor passing
will be used to send them to libvirtd, which will them pass
them down to libvirt_lxc, which will then pass them to the container
init process.

This will only be implemented for LXC right now, but the design
is generic enough it could work with other hypervisors, hence
I suggest adding this to libvirt.so, rather than libvirt-lxc.so
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Add support for creating disk-only (no memory) snapshots in esx, and
for quiescing the VM before taking the snapshot. The VMware API
supports these operations directly, so adding support to libvirt is
just a matter of setting the flags correctly when calling
VMware. VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY and
VIR_DOMAIN_SNAPSHOT_CREATE_QUIESCE are now valid flags for esx.
Signed-off-by: NEric Blake <eblake@redhat.com>

Although, having it depending on Xen >= 4.3 (by using the proper
libxl feature flag).

Xen currently implements a NUMA placement policy which is basically
the same as the 'interleaved' policy of `numactl', although it can
be applied on a subset of the available nodes. We therefore hardcode
"interleave" as 'numa_mode', and we use the newly introduced libxl
interface to figure out what nodes a domain spans ('numa_nodeset').

With this change, it is now possible to query the NUMA node
affinity of a running domain:

[raistlin@Zhaman ~]$ sudo virsh --connect xen:/// list
 Id    Name                           State
----------------------------------------------------
 23    F18_x64                        running

[raistlin@Zhaman ~]$ sudo virsh --connect xen:/// numatune 23
numa_mode      : interleave
numa_nodeset   : 1
Signed-off-by: NDario Faggioli <dario.faggioli@citrix.com>

domainGetNumaParameters has a string typed parameter, hence it
is necessary for the libxl driver to support this.

This change implements the connectSupportsFeature hook for the
libxl driver, advertising that VIR_DRV_FEATURE_TYPED_PARAM_STRING
is supported.
Signed-off-by: NDario Faggioli <dario.faggioli@citrix.com>
Cc: Eric Blake <eblake@redhat.com>

Xen 4.3 changes sysctl version to 10 and domctl version to 9. Update
the hypervisor driver to work with those.
Signed-off-by: NStefan Bader <stefan.bader@canonical.com>