Format all functions with two blank lines between, and return type
on separate line from function name.  Also break some lines longer
than 80 columns.  This makes the subsequent macro refactoring
less noisy.

* src/util/vircgroup.c: Match prevailing style.
Signed-off-by: NEric Blake <eblake@redhat.com>

Recentish (2011) kernels introduced a new device called /dev/loop-control,
which causes libvirt's detection of loop devices to get confused
since it only checks for a prefix of 'loop'. Also check that the
next character is a digit
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

This is a second attempt at fixing the problem first attempted
in commit 2df8d991; basically undoing the fact that it was
reverted in commit 43cee32f, plus fixing two more issues: the
code in configure.ac has to EXACTLY match virnetdevbridge.c
with regards to declaring in6 types before using if_bridge.h,
and the fact that RHEL 5 has even more conflicts:

In file included from util/virnetdevbridge.c:49:
/usr/include/linux/in6.h:47: error: conflicting types for 'in6addr_any'
/usr/include/netinet/in.h:206: error: previous declaration of 'in6addr_any' was here
/usr/include/linux/in6.h:49: error: conflicting types for 'in6addr_loopback'
/usr/include/netinet/in.h:207: error: previous declaration of 'in6addr_loopback' was here

The rest of this commit message borrows from the original try
of 2df8d991:

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.
* src/util/virnetdevbridge.c (includes): Also sanitize for RHEL 5.
Signed-off-by: NEric Blake <eblake@redhat.com>

Commit 3d0e3c1a reintroduced a problem previously squelched in
commit 7e5aa78d.  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: NEric Blake <eblake@redhat.com>

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.

The journald code would crash if a NULL was passed for the
filename / funcname in the logging code. This shouldn't
happen in general, but it is better to be safe, since there
have been bugs triggering this.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

*src/util/virstoragefile.c: Add a helper function to get
the first name of missing backing files, if the name is NULL,
it means the diskchain is not broken.
*src/qemu/qemu_domain.c: qemuDiskChainCheckBroken(disk) to
check if its chain is broken

Make the virCgroupNewMachine method try to use systemd-machined
first. If that fails, then fallback to using the traditional
cgroup setup code path.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

When systemd is involved in managing processes, it may start
killing off & tearing down croups associated with the process
while we're still doing virCgroupKillPainfully. We must
explicitly check for ENOENT and treat it as if we had finished
killing processes
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Systemd uses a named cgroup mount for tracking processes. Add
it as another type of controller, albeit one which we have to
special case in a number of places. In particular we must
never create/delete directories there, nor add tasks. Essentially
the systemd mount is to be considered read-only for libvirt.

With this change both the virCgroupDetectPlacement and
virCgroupCopyPlacement methods must be invoked. The copy
placement method will copy setup for resource controllers
only. The detect placement method will probe for any
named controllers, or resource controllers not already
setup.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

There are some interesting escaping rules to consider when dealing
with systemd slice/scope names. Thus it is helpful to have APIs
for formatting names
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

This function is needed for virt-login-shell.  Also modify virGirUserDirectory
to use the new function, to simplify the code.
Signed-off-by: NEric Blake <eblake@redhat.com>

The way we were casting small (<32bit) integers was broken
on big endian hosts, causing stack smashing. This was detected
in the test suite either by test failures due to incorrect
results, or by libc/gcc abort'ing with its stack canary
triggered.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Depending on the set of mingw packages installed, it is possible
that other .c files hit the mingw header pollution from the
virdbus.h file.

In file included from ../../src/rpc/virnetserver.c:39:0:
../../src/util/virdbus.h:41:35: error: expected ';', ',' or ')' before 'struct'
                       const char *interface,
                                   ^

* src/util/virdbus.h (virDBusCallMethod): Match .c file change.
Signed-off-by: NEric Blake <eblake@redhat.com>

On platforms without decent group support, the build failed:

Cannot export virGetGroupList: symbol not defined
./.libs/libvirt_security_manager.a(libvirt_security_manager_la-security_dac.o): In function `virSecurityDACPreFork':
/home/eblake/libvirt-tmp/build/src/../../src/security/security_dac.c:248: undefined reference to `virGetGroupList'
collect2: error: ld returned 1 exit status

* src/util/virutil.c (virGetGroupList): Provide dummy implementation.
Signed-off-by: NEric Blake <eblake@redhat.com>

Our recent conversion to make VIR_ALLOC report oom wasn't
tested on mingw:

In file included from ../../src/util/virthread.c:29:0:
../../src/util/virthreadwin32.c: In function 'virCondWait':
../../src/util/virthreadwin32.c:166:81: error: 'VIR_FROM_THIS' undeclared (first use in this function)
     if (VIR_REALLOC_N(c->waiters, c->nwaiters + 1) < 0) {
                                                                                 ^

* src/util/virthreadwin32.c (VIR_FROM_THIS): Define.
Signed-off-by: NEric Blake <eblake@redhat.com>

Mingw headers pollute the namespace.

  CC       libvirt_util_la-virdbus.lo
../../src/util/virdbus.c:1102:35: error: expected ';', ',' or ')' before 'struct'
                       const char *interface,
                                   ^

* src/util/virdbus.c (virDBusCallMethod): Avoid 'interface'.
Signed-off-by: NEric Blake <eblake@redhat.com>

The previous patch was incomplete.

  CC       libvirt_util_la-vircgroup.lo
../../src/util/vircgroup.c:70:12: error: 'virCgroupPartitionEscape' declared 'static' but never defined [-Werror=unused-function]
 static int virCgroupPartitionEscape(char **path);
            ^

* src/util/vircgroup.c (virCgroupPartitionEscape): Move forward
declaration inside conditional.
Signed-off-by: NEric Blake <eblake@redhat.com>

The virCgroupValidateMachineGroup method calls some functions
which are only conditionally compiled, thus it too must be
made conditional. This fixes the build on non-Linux hosts.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

If the app has provided a whitelist of controllers to be used,
we skip detecting its mount point. We still, however, fill in
the placement info which later confuses the machine name
validation code. Skip detecting placement if the controller
mount point is not set
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

When detecting cgroups we must honour any controllers
whitelist the driver may have.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

When a VM has an 'emulator' child cgroup present, we must
strip off that suffix when detecting the cgroup for a
machine

Rename the virCgroupIsValidMachineGroup method to
virCgroupValidateMachineGroup to make a bit clearer
that this isn't simply a boolean check, it will make
changes to the object.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The virCgroupIsValidMachine does not need to be called from
outside the cgroups file now, so make it static.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Instead of requiring drivers to use a combination of calls
to virCgroupNewDetect and virCgroupIsValidMachine, combine
the two into virCgroupNewDetectMachine
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Add protection such that the virCgroupRemove and
virCgroupKill* do not do anything to the root cgroup.

Killing all PIDs in the root cgroup does not end well.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Instead of requiring one API call to create a cgroup and
another to add a task to it, introduce a new API
virCgroupNewMachine which does both jobs at once. This
will facilitate the later code to talk to systemd to
achieve this job which is also atomic.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

As we do for other errors with an extra string.

virCgroupAvailable() implementation calls getmntent_r
without checking if HAVE_GETMNTENT_R is defined, so it fails
to build on platforms without getmntent_r support.

Make virCgroupAvailable() just return false without
HAVE_GETMNTENT_R.

Parsing 'user:group' is useful even outside the DAC security driver,
so expose the most abstract function which has no DAC security driver
bits in itself.

Thanks to a lack of coordination between kernel and glibc folks,
it has been impossible to mix code using <linux/in.h> and
<net/in.h> for some time now (see for example commit c308a9ae).
On at least RHEL 6, <linux/if_bridge.h> tries to use the kernel
side, and fails due to our desire to use the glibc side elsewhere:

In file included from /usr/include/linux/if_bridge.h:17,
                 from util/virnetdevbridge.c:42:
/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’

Thankfully, the kernel layout of these structs is ABI-compatible,
they only differ in the type system presented to the C compiler.
While there are other versions of kernel headers that avoid the
problem, it is easier to just work around the issue than to expect
all developers to upgrade to working kernel headers.

* src/util/virnetdevbridge.c (includes): Coerce the kernel version
of in.h to not collide with the normal version.
Signed-off-by: NEric Blake <eblake@redhat.com>

dbus 1.2.24 (on RHEL 6) lacks DBUS_TYPE_UNIX_FD; but as we aren't
trying to pass one of those anyways, we can just drop support for
it in our wrapper.  Solves this build error introduced in commit
834c9c94:

  CC     libvirt_util_la-virdbus.lo
util/virdbus.c:242: error: 'DBUS_TYPE_UNIX_FD' undeclared here (not in a function)

* src/util/virdbus.c (virDBusBasicTypes): Drop support for unix fds.
Signed-off-by: NEric Blake <eblake@redhat.com>

The virCgroupNewDomainDriver and virCgroupNewDriver methods
are obsolete now that we can auto-detect existing cgroup
placement. Delete them to reduce code bloat.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Add virCgroupIsValidMachine API to check whether an auto
detected cgroup is valid for a machine. This lets us
check if a VM has just been placed into some generic
shared cgroup, or worse, the root cgroup
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Add a virCgroupNewDetect API which is used to initialize a
cgroup object with the placement of an arbitrary process.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

If systemd machine does not exist, return -2 instead of -1,
so that applications don't need to repeat the tedious error
checking code
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Current code for handling dbus errors only works for errors
received from the remote application itself. We must also
handle errors emitted by the bus itself, for example, when
it fails to spawn the target service.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Commit 834c9c94 introduced virDBusMessageEncode and
virDBusMessageDecode functions, however corresponding stubs
were not added to !WITH_DBUS section, therefore 'make check'
started to fail when compiled w/out dbus support like that:

Expected symbol virDBusMessageDecode is not in ELF library

Convert the remaining methods in vircgroup.c to report errors
instead of returning errno values.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Instead of returning errno values, change the virCgroupKill*
APIs to fully report errors.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Instead of returning raw errno values, report full libvirt
errors in virCgroupNew* functions.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>