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>

Add virErrorSetErrnoFromLastError and virLastErrorIsSystemErrno
to simplify code which wants to handle system errors in a more
graceful fashion.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

To register virtual machines and containers with systemd-machined,
and thus have cgroups auto-created, we need to talk over DBus.
This is somewhat tedious code, so introduce a dedicated function
to isolate the DBus call in one place.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Doing DBus method calls using libdbus.so is tedious in the
extreme. systemd developers came up with a nice high level
API for DBus method calls (sd_bus_call_method). While
systemd doesn't use libdbus.so, their API design can easily
be ported to libdbus.so.

This patch thus introduces methods virDBusCallMethod &
virDBusMessageRead, which are based on the code used for
sd_bus_call_method and sd_bus_message_read. This code in
systemd is under the LGPLv2+, so we're license compatible.

This code is probably pretty unintelligible unless you are
familiar with the DBus type system. So I added some API
docs trying to explain how to use them, as well as test
cases to validate that I didn't screw up the adaptation
from the original systemd code.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

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

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>