Add an impl of +virGetUserRuntimeDirectory, virGetUserCacheDirectory
virGetUserConfigDirectory and virGetUserDirectory for Win32 platform.
Also create stubs for non-Win32 platforms which lack getpwuid_r()

In adding these two helpers were added virFileIsAbsPath and
virFileSkipRoot, along with some macros VIR_FILE_DIR_SEPARATOR,
VIR_FILE_DIR_SEPARATOR_S, VIR_FILE_IS_DIR_SEPARATOR,
VIR_FILE_PATH_SEPARATOR, VIR_FILE_PATH_SEPARATOR_S

All this code was adapted from GLib2 under terms of LGPLv2+ license.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Remove the uid param from virGetUserConfigDirectory,
virGetUserCacheDirectory, virGetUserRuntimeDirectory,
and virGetUserDirectory

These functions were universally called with the
results of getuid() or geteuid(). To make it practical
to port to Win32, remove the uid parameter and hardcode
geteuid()
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Add a VIR_ERR_DOMAIN_LAST sentinel for virErrorDomain and
replace the virErrorDomainName function by a VIR_ENUM_IMPL

In the process the naming of error domains is sanitized

* src/util/virterror.c: Use VIR_ENUM_IMPL for converting
  error domains to strings
* include/libvirt/virterror.h: Add VIR_ERR_DOMAIN_LAST

The libvirt_private.syms file exports virNetlinkEventServiceLocalPid
so there needs to be a no-op stub for Win32 to avoid linker errors
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

I'm tired of writing:

bool sep = false;
while (...) {
    if (sep)
       virBufferAddChar(buf, ',');
    sep = true;
    virBufferAdd(buf, str);
}

This makes it easier, allowing one to write:

while (...)
    virBufferAsprintf(buf, "%s,", str);
virBufferTrim(buf, ",", -1);

to trim any remaining comma.

* src/util/buf.h (virBufferTrim): Declare.
* src/util/buf.c (virBufferTrim): New function.
* tests/virbuftest.c (testBufTrim): Test it.

We were being lazy - virnetlink.c was getting uint32_t as a
side-effect from glibc 2.14's <unistd.h>, but older glibc 2.11
does not provide uint32_t from <unistd.h>.  In fact, POSIX states
that <unistd.h> need only provide intptr_t, not all of <stdint.h>,
so the bug really is ours.  Reported by Jonathan Alescio.

* src/util/virnetlink.h: Include <stdint.h>.

This involves setting the cpuacct cgroup to a per-vcpu granularity,
as well as summing the each vcpu accounting into a common array.
Now that we are reading more than one cgroup file, we double-check
that cpus weren't hot-plugged between reads to invalidate our
summing.
Signed-off-by: NEric Blake <eblake@redhat.com>

Allow the logging APIs to be called with a va_list for format
args, instead of requiring var-args usage.

* src/util/logging.h, src/util/logging.c: Add virLogVMessage

The use of readlink() in lxc_container.c is intentional; we don't
want an absolute pathname there.

* src/util/cgroup.h (VIR_CGROUP_SYSFS_MOUNT): Indent properly.
* cfg.mk (exclude_file_name_regexp--sc_prohibit_readlink): Add
exemption.

Normal practice is for cgroups controllers to be mounted at
/sys/fs/cgroup. When setting up a container, /sys is mounted
with a new sysfs instance, thus we must re-mount all the
cgroups controllers. The complexity is that we must mount
them in the same layout as the host OS. ie if 'cpu' and 'cpuacct'
were mounted at the same location in the host we must preserve
this in the container. Also if any controllers are co-located
we must setup symlinks from the individual controller name to
the co-located mount-point
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Callers of virGetUser{Config,Runtime,Cache}Directory all
append further path component. We should not be
adding a trailing slash in the return path otherwise we
get paths containing '//'
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Sometimes it is useful to see the callpath for log messages.
This change enhances the log filter syntax so that stack traces
can be show by setting '1:+NAME' instead of '1:NAME'.

This results in output like:

2012-05-09 14:18:45.136+0000: 13314: debug : virInitialize:414 : register drivers
/home/berrange/src/virt/libvirt/src/.libs/libvirt.so.0(virInitialize+0xd6)[0x7f89188ebe86]
/home/berrange/src/virt/libvirt/tools/.libs/lt-virsh[0x431921]
/lib64/libc.so.6(__libc_start_main+0xf5)[0x3a21e21735]
/home/berrange/src/virt/libvirt/tools/.libs/lt-virsh[0x40a279]

2012-05-09 14:18:45.136+0000: 13314: debug : virRegisterDriver:775 : driver=0x7f8918d02760 name=Test
/home/berrange/src/virt/libvirt/src/.libs/libvirt.so.0(virRegisterDriver+0x6b)[0x7f89188ec717]
/home/berrange/src/virt/libvirt/src/.libs/libvirt.so.0(+0x11b3ad)[0x7f891891e3ad]
/home/berrange/src/virt/libvirt/src/.libs/libvirt.so.0(virInitialize+0xf3)[0x7f89188ebea3]
/home/berrange/src/virt/libvirt/tools/.libs/lt-virsh[0x431921]
/lib64/libc.so.6(__libc_start_main+0xf5)[0x3a21e21735]
/home/berrange/src/virt/libvirt/tools/.libs/lt-virsh[0x40a279]

* docs/logging.html.in: Document new syntax
* configure.ac: Check for execinfo.h
* src/util/logging.c, src/util/logging.h: Add support for
  stack traces
* tests/testutils.c: Adapt to API change
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

As defined in:
http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html

This offers a number of advantages:
 * Allows sharing a home directory between different machines, or
sessions (eg. using NFS)
 * Cleanly separates cache, runtime (eg. sockets), or app data from
user settings
 * Supports performing smart or selective migration of settings
between different OS versions
 * Supports reseting settings without breaking things
 * Makes it possible to clear cache data to make room when the disk
is filling up
 * Allows us to write a robust and efficient backup solution
 * Allows an admin flexibility to change where data and settings are stored
 * Dramatically reduces the complexity and incoherence of the
system for administrators

Commit 64297313 added three direct
references to nl_handle_* instead of using our aliases which hide
differences between libnl-3 and libnl-1.

Until now, the nl_pid of the source address of every message sent by
virNetlinkCommand has been set to the value of getpid(). Most of the
time this doesn't matter, and in the one case where it does
(communication with lldpad), it previously was the proper thing to do,
because the netlink event service (which listens on a netlink socket
for unsolicited messages from lldpad) coincidentally always happened
to bind with a local nl_pid == getpid().

With the fix for:

  https://bugzilla.redhat.com/show_bug.cgi?id=816465

that particular nl_pid is now effectively a reserved value, so the
netlink event service will always bind to something else
(coincidentally "getpid() + (1 << 22)", but it really could be
anything). The result is that communication between lldpad and
libvirtd is broken (lldpad gets a "disconnected" error when it tries
to send a directed message).

The solution to this problem caused by a solution, is to query the
netlink event service's nlhandle for its "local_port", and send that
as the source nl_pid (but only when sending to lldpad, of course - in
other cases we maintain the old behavior of sending getpid()).

There are two cases where a message is being directed at lldpad - one
in virNetDevLinkDump, and one in virNetDevVPortProfileOpSetLink.

The case of virNetDevVPortProfileOpSetLink is simplest to explain -
only if !nltarget_kernel, i.e. the message isn't targetted for the
kernel, is the dst_pid set (by calling
virNetDevVPortProfileGetLldpadPid()), so only in that case do we call
virNetlinkEventServiceLocalPid() to set src_pid.

For virNetDevLinkDump, it's a bit more complicated. The call to
virNetDevVPortProfileGetLldpadPid() was effectively up one level (in
virNetDevVPortProfileOpCommon), although obscured by an unnecessary
passing of a function pointer. This patch removes the function
pointer, and calls virNetDevVPortProfileGetLldpadPid() directly in
virNetDevVPortProfileOpCommon - if it's doing this, it knows that it
should also call virNetlinkEventServiceLocalPid() to set src_pid too;
then it just passes src_pid and dst_pid down to
virNetDevLinkDump. Since (src_pid == 0 && dst_pid == 0) implies that
the kernel is the destination, there is no longer any need to send
nltarget_kernel as an arg to virNetDevLinkDump, so it's been removed.

The disparity between src_pid being int and dst_pid being uint32_t may
be a bit disconcerting to some, but I didn't want to complicate
virNetlinkEventServiceLocalPid() by having status returned separately
from the value.

This value will be needed to set the src_pid when sending netlink
messages to lldpad. It is part of the solution to:

  https://bugzilla.redhat.com/show_bug.cgi?id=816465

Note that libnl's port generation algorithm guarantees that the
nl_socket_get_local_port() will always be > 0 (since it is "getpid() +
(n << 22>" where n is always < 1024), so it is okay to cast the
uint32_t to int (thus allowing us to use -1 as an error sentinel).

Until now, virNetlinkCommand has assumed that the nl_pid in the source
address of outgoing netlink messages should always be the return value
of getpid(). In most cases it actually doesn't matter, but in the case
of communication with lldpad, lldpad saves this info and later uses it
to send netlink messages back to libvirt. A recent patch to fix Bug
816465 changed the order of the universe such that the netlink event
service socket is no longer bound with nl_pid == getpid(), so lldpad
could no longer send unsolicited messages to libvirtd. Adding src_pid
as an argument to virNetlinkCommand() is the first step in notifying
lldpad of the proper address of the netlink event service socket.

This is part of the solution to the problem detailed in:

  https://bugzilla.redhat.com/show_bug.cgi?id=816465

and further detailed in

  https://www.redhat.com/archives/libvir-list/2012-May/msg00202.htm

A short explanation is included in the comments of the patch itself.

Note that this patch by itself breaks communication between lldpad and
libvirtd, so the other 3 patches in the series must be applied at the
same time as this patch.

usbFindDevice():get usb device according to
                idVendor, idProduct, bus, device
                it is the exact match of the four parameters

usbFindDeviceByBus():get usb device according to bus, device
                  it returns only one usb device same as usbFindDevice

usbFindDeviceByVendor():get usb device according to idVendor,idProduct
                     it probably returns multiple usb devices.

usbDeviceSearch(): a helper function to do the actual search

These two functions are called from main() on all platforms, and
always return success on platforms that don't support libnl. They
still log an error message, though, which doesn't make sense - they
should just be NOPs on those platforms. (Per a suggestion during
review, I've turned the logs into debug messages rather than removing
them completely).

Error: STRING_NULL:
/libvirt/src/util/uuid.c:273:
string_null_argument: Function "getDMISystemUUID" does not terminate string "*dmiuuid".
/libvirt/src/util/uuid.c:241:
string_null_argument: Function "saferead" fills array "*uuid" with a non-terminated string.
/libvirt/src/util/util.c:101:
string_null_argument: Function "read" fills array "*buf" with a non-terminated string.
/libvirt/src/util/uuid.c:274:
string_null: Passing unterminated string "dmiuuid" to a function expecting a null-terminated string.
/libvirt/src/util/uuid.c:138:
var_assign_parm: Assigning: "cur" = "uuidstr". They now point to the same thing.
/libvirt/src/util/uuid.c:164:
string_null_sink_loop: Searching for null termination in an unterminated array "cur".

configure.ac: check for libnl-3 in addition to libnl-1

src/Makefile.am: link against libnl when needed

src/util/virnetlink.c:
support libnl3 api.  To minimize impact on code flow, wrap the
differences under the virNetlink* namespace.

Unfortunately libnl3 moves netlink/msg.h to
/usr/include/libnl3/netlink/msg.h, so the LIBNL_CFLAGS need to be added
to a bunch of places where they weren't needed with libnl1.
Signed-off-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

Add function virJSONValueObjectKeysNumber, virJSONValueObjectGetKey
and virJSONValueObjectGetValue, which allow you to iterate over all
fields of json object: you can get number of fields and then get
name and value, stored in field with that name by index.
Signed-off-by: NDmitry Guryanov <dguryanov@parallels.com>

The code uses long long for pid_t now.
It fails on mingw64 without this change.

Fix a few more places where pid_t is printed with wrong type

In fact, the 'tapfd' is always NULL, the function 'virNetDevTapCreate()' hasn't
assign 'fd' to 'tapfd', when the function 'virNetDevSetMAC()' is failed then
goto 'error' label, finally, the VIR_FORCE_CLOSE() will deref a NULL 'tapfd'.

* util/virnetdevtap.c (virNetDevTapCreateInBridgePort): fix a NULL pointer derefing.

* How to reproduce?

$ cat > /tmp/net.xml <<EOF
<network>
  <name>test</name>
  <forward mode='nat'/>
  <bridge name='br1' stp='off' delay='1' />
  <mac address='00:00:00:00:00:00'/>
  <ip address='192.168.100.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.100.2' end='192.168.100.254' />
    </dhcp>
  </ip>
</network>
EOF

$ virsh net-define /tmp/net.xml

$ virsh net-start test
error: Failed to start network brTest
error: End of file while reading data: Input/output error
Signed-off-by: NAlex Jia <ajia@redhat.com>

When libvirtd is started, we create "libvirt/qemu" directories under
hugetlbfs mount point. Only the "qemu" subdirectory is chowned to qemu
user and "libvirt" remains owned by root. If umask was too restrictive
when libvirtd started, qemu user may lose access to "qemu"
subdirectory. Let's explicitly grant search permissions to "libvirt"
directory for all users.

Below patch fixes the following coverity findings

Error: OVERRUN_STATIC:
/libvirt/src/qemu/qemu_command.c:152:
overrun-buffer-val: Overrunning static array "net->mac" of size 6 bytes by passing it as an argument to a function which indexes it at byte position 15.
/libvirt/src/util/virnetdevmacvlan.c:948:
access_dbuff_const: Calling "virNetDevMacVLanVPortProfileRegisterCallback" indexes array "macaddress" at byte position 15.
/libvirt/src/util/virnetdevmacvlan.c:773:
access_dbuff_const: Calling "memcpy" indexes array "macaddress" with index "16UL" at byte position 15.

Error: OVERRUN_STATIC:
/libvirt/src/qemu/qemu_migration.c:2744:
overrun-buffer-val: Overrunning static array "net->mac" of size 6 bytes by passing it as an argument to a function which indexes it at byte position 15.
/libvirt/src/util/virnetdevmacvlan.c:773:
access_dbuff_const: Calling "memcpy" indexes array "macaddress" with index "16UL" at byte position 15.

Error: OVERRUN_STATIC:
/libvirt/src/qemu/qemu_driver.c:435:
overrun-buffer-val: Overrunning static array "net->mac" of size 6 bytes by passing it as an argument to a function which indexes it at byte position 15.
/libvirt/src/util/virnetdevmacvlan.c:1036:
access_dbuff_const: Calling "virNetDevMacVLanVPortProfileRegisterCallback" indexes array "macaddress" at byte position 15.
/libvirt/src/util/virnetdevmacvlan.c:773:
access_dbuff_const: Calling "memcpy" indexes array "macaddress" with index "16UL" at byte position 15.

Some of the error messages in this function should have been
virReportSystemError (since they have an errno they want to log), but
were mistakenly written as netlinkError, which expects a libvirt error
code instead. The result was that when one of the errors was
encountered, "No error message provided" would be printed instead of
something meaningful (see
https://bugzilla.redhat.com/show_bug.cgi?id=816465 for an example).

This patch resolves https://bugzilla.redhat.com/show_bug.cgi?id=815270

The function virNetDevMacVLanVPortProfileRegisterCallback() takes an
arg "virtPortProfile", and was checking it for non-NULL before using
it. However, the prototype for
virNetDevMacVLanPortProfileRegisterCallback had marked that arg with
ATTRIBUTE_NONNULL(). Contrary to what one may think,
ATTRIBUTE_NONNULL() does not provide any guarantee that an arg marked
as such really is always non-null; the only effect to the code
generated by gcc, is that gcc *assumes* it is non-NULL; this results
in, for example, the check for a non-NULL value being optimized out.

(Unfortunately, this code removal only occurs when optimization is
enabled, and I am in the habit of doing local builds with optimization
off to ease debugging, so the bug didn't show up in my earlier local
testing).

In general, virPortProfile might always be NULL, so it shouldn't be
marked as ATTRIBUTE_NONNULL. One other function prototype made this
same error, so this patch fixes it as well.

Add 2 new functions to the virSocketAddr 'class':

- virSocketAddrEqual: tests whether two IP addresses and their ports are equal
- virSocketaddSetIPv4Addr: set a virSocketAddr given a 32 bit int

Use embedded buffers for the MAC addresses and the VM's UUID.

This patch improves the previously added virAtomicInt implementation
by using gcc-builtins if possible. The needed builtins are available
since GCC >= 4.1. At least the 4.0 docs don't mention them.

This patch introduces a new block job, useful for live storage
migration using pre-copy streaming.  Justification for including
this under virDomainBlockRebase rather than adding a new command
includes: 1) there are now two possible block jobs in qemu, with
virDomainBlockRebase starting either type of command, and
virDomainBlockJobInfo and virDomainBlockJobAbort working to end
either type; 2) reusing this command allows distros to backport
this feature to the libvirt 0.9.10 API without a .so bump.

Note that a future patch may add a more powerful interface named
virDomainBlockJobCopy, dedicated to just the block copy job, in
order to expose even more options (such as setting an arbitrary
format type for the destination without having to probe it from a
pre-existing destination file); adding a new command for targetting
just block copy would be similar to how we already have
virDomainBlockPull for targetting just the block pull job.

Using a live VM with the backing chain:
  base <- snap1 <- snap2
as the starting point, we have:

- virDomainBlockRebase(dom, disk, "/path/to/copy", 0,
    VIR_DOMAIN_BLOCK_REBASE_COPY)
creates /path/to/copy with the same format as snap2, with no backing
file, so entire chain is copied and flattened

- virDomainBlockRebase(dom, disk, "/path/to/copy", 0,
    VIR_DOMAIN_BLOCK_REBASE_COPY|VIR_DOMAIN_BLOCK_REBASE_COPY_RAW)
creates /path/to/copy as a raw file, so entire chain is copied and
flattened

- virDomainBlockRebase(dom, disk, "/path/to/copy", 0,
    VIR_DOMAIN_BLOCK_REBASE_COPY|VIR_DOMAIN_BLOCK_REBASE_SHALLOW)
creates /path/to/copy with the same format as snap2, but with snap1 as
a backing file, so only snap2 is copied.

- virDomainBlockRebase(dom, disk, "/path/to/copy", 0,
    VIR_DOMAIN_BLOCK_REBASE_COPY|VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT)
reuse existing /path/to/copy (must have empty contents, and format is
probed[*] from the metadata), and copy the full chain

- virDomainBlockRebase(dom, disk, "/path/to/copy", 0,
    VIR_DOMAIN_BLOCK_REBASE_COPY|VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT|
    VIR_DOMAIN_BLOCK_REBASE_SHALLOW)
reuse existing /path/to/copy (contents must be identical to snap1,
and format is probed[*] from the metadata), and copy only the contents
of snap2

- virDomainBlockRebase(dom, disk, "/path/to/copy", 0,
    VIR_DOMAIN_BLOCK_REBASE_COPY|VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT|
    VIR_DOMAIN_BLOCK_REBASE_SHALLOW|VIR_DOMAIN_BLOCK_REBASE_COPY_RAW)
reuse existing /path/to/copy (must be raw volume with contents
identical to snap1), and copy only the contents of snap2

Less useful combinations:

- virDomainBlockRebase(dom, disk, "/path/to/copy", 0,
    VIR_DOMAIN_BLOCK_REBASE_COPY|VIR_DOMAIN_BLOCK_REBASE_SHALLOW|
    VIR_DOMAIN_BLOCK_REBASE_COPY_RAW)
fail if source is not raw, otherwise create /path/to/copy as raw and
the single file is copied (no chain involved)

- virDomainBlockRebase(dom, disk, "/path/to/copy", 0,
    VIR_DOMAIN_BLOCK_REBASE_COPY|VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT|
    VIR_DOMAIN_BLOCK_REBASE_COPY_RAW)
makes little sense: the destination must be raw but have no contents,
meaning that it is an empty file, so there is nothing to reuse

The other three flags are rejected without VIR_DOMAIN_BLOCK_COPY.

[*] Note that probing an existing file for its format can be a security
risk _if_ there is a possibility that the existing file is 'raw', in
which case the guest can manipulate the file to appear like some other
format.  But, by virtue of the VIR_DOMAIN_BLOCK_REBASE_COPY_RAW flag,
it is possible to avoid probing of raw files, at which point, probing
of any remaining file type is no longer a security risk.

It would be nice if we could issue an event when pivoting from phase 1
to phase 2, but qemu hasn't implemented that, and we would have to poll
in order to synthesize it ourselves.  Meanwhile, qemu will give us a
distinct job info and completion event when we either cancel or pivot
to end the job.  Pivoting is accomplished via the new:

virDomainBlockJobAbort(dom, disk, VIR_DOMAIN_BLOCK_JOB_ABORT_PIVOT)

Management applications can pre-create the copy with a relative
backing file name, and use the VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT
flag to have qemu reuse the metadata; if the management application
also copies the backing files to a new location, this can be used
to perform live storage migration of an entire backing chain.

* include/libvirt/libvirt.h.in (VIR_DOMAIN_BLOCK_JOB_TYPE_COPY):
New block job type.
(virDomainBlockJobAbortFlags, virDomainBlockRebaseFlags): New enums.
* src/libvirt.c (virDomainBlockRebase): Document the new flags,
and implement general restrictions on flag combinations.
(virDomainBlockJobAbort): Document the new flag.
(virDomainSaveFlags, virDomainSnapshotCreateXML)
(virDomainRevertToSnapshot, virDomainDetachDeviceFlags): Document
restrictions.
* include/libvirt/virterror.h (VIR_ERR_BLOCK_COPY_ACTIVE): New
error.
* src/util/virterror.c (virErrorMsg): Define it.

virThreadSelf tries to access the virThreadPtr stored in TLS for the
current thread via TlsGetValue. When virThreadSelf is called on a thread
that was not created via virThreadCreate (e.g. the main thread) then
TlsGetValue returns NULL as TlsAlloc initializes TLS slots to NULL.

virThreadSelf can be called on the main thread via this call chain from
virsh

vshDeinit
virEventAddTimeout
virEventPollAddTimeout
virEventPollInterruptLocked
virThreadIsSelf

triggering a segfault as virThreadSelf unconditionally dereferences the
return value of TlsGetValue.

Fix this by making virThreadSelf check the TLS slot value for NULL and
setting the given virThreadPtr accordingly.

Reported by Marcel Müller.

Ensure we don't introduce any more lousy integer parsing in new
code, while avoiding a scrub-down of existing legacy code.

Note that we also need to enable sc_prohibit_atoi_atof (see cfg.mk
local-checks-to-skip) before we are bulletproof, but that also
entails scrubbing I'm not ready to do at the moment.

* src/util/util.c (virStrToLong_i, virStrToLong_ui)
(virStrToLong_l, virStrToLong_ul, virStrToLong_ll)
(virStrToLong_ull, virStrToDouble): Mark exemptions.
* src/util/virmacaddr.c (virMacAddrParse): Likewise.
* cfg.mk (sc_prohibit_strtol): New syntax check.
(exclude_file_name_regexp--sc_prohibit_strtol): Ignore files that
I'm not willing to fix yet.
(local-checks-to-skip): Re-enable sc_prohibit_atoi_atof.

https://bugzilla.redhat.com/show_bug.cgi?id=617711 reported that
even with my recent patched to allow <memory unit='G'>1</memory>,
people can still get away with trying <memory>1G</memory> and
silently get <memory unit='KiB'>1</memory> instead.  While
virt-xml-validate catches the error, our C parser did not.

Not to mention that it's always fun to fix bugs while reducing
lines of code.  :)

* src/conf/domain_conf.c (virDomainParseMemory): Check for parse error.
(virDomainDefParseXML): Avoid strtoll.
* src/conf/storage_conf.c (virStorageDefParsePerms): Likewise.
* src/util/xml.c (virXPathLongBase, virXPathULongBase)
(virXPathULongLong, virXPathLongLong): Likewise.

DBus connection. The HAL device code further requires that
the DBus connection is integrated with the event loop and
provides such glue logic itself.

The forthcoming FirewallD integration also requires a
dbus connection with event loop integration. Thus we need
to pull the current event loop glue out of the HAL driver.

Thus we create src/util/virdbus.{c,h} files. This contains
just one method virDBusGetSystemBus() which obtains a handle
to the single shared system bus instance, with event glue
automagically setup.

For threading support, add atomic add and sub operations working on
integers. Base this on locking support provided by virMutex.