This part adds support to domain_conf.{c|h} for parsing the new
interface XML of type 'direct'. The parsed mode is now stored as
an int.
* src/conf/domain_conf.c src/conf/domain_conf.h: extend parsing code
* src/util/macvtap.h: empty header to not break compilation

This patch adds build support for libvirt checking for certain contents
of /usr/include/linux/if_link.h to see whether macvtap support is
compilable on that system. One can disable macvtap support in libvirt
via --without-macvtap passed to configure.
* configure.ac src/Makefile.am: new build support
* src/libvirt_macvtap.syms: list of exported symbols
* src/util/macvtap.c: empty module to not break compilation

* src/util/hostusb.c: The device path for a USB device wants the
  bus/device IDs in decimal not octal

All callers now pass a NULL virConnectPtr into the USB/PCi device
iterator functions. Therefore the virConnectPtr arg can now be
removed from these functions

* src/util/hostusb.h, src/util/hostusb.c: Remove virConnectPtr
  from usbDeviceFileIterate
* src/util/pci.c, src/util/pci.h: Remove virConnectPtr arg from
  pciDeviceFileIterate
* src/qemu/qemu_security_dac.c, src/security/security_selinux.c: Update
  to drop redundant virConnectPtr arg

* src/util/util.h (virAsprintf): Remove ATTRIBUTE_RETURN_CHECK, since
it is perfectly fine to ignore the return value, now that the pointer
is guaranteed to be set to NULL upon failure.
* src/util/storage_file.c (absolutePathFromBaseFile): Remove now-
unnecessary use of ignore_value.

* src/util/storage_file.c (absolutePathFromBaseFile): While this use
of virAsprintf is slightly cleaner than using stpncpy(stpcpy(...,
it does impose an artificial limitation on the length of the base_file
name.  Rather than asserting that it does not exceed INT_MAX, return
NULL when it does.

It was used for error reporting only.

It was used for error reporting only.

It was used for error reporting only.

It was used for error reporting only.

It was used for error reporting only.

It was used for error reporting only.

When configured with --enable-gcc-warnings, it didn't even compile.
* src/util/storage_file.c: Include <assert.h>.
(absolutePathFromBaseFile): Assert that converting size_t to int is valid.
Reverse length/string args to match "%.*s".
Explicitly ignore the return value of virAsprintf.

* src/util/storage_file.c: Include "dirname.h".
(absolutePathFromBaseFile): Rewrite not to leak, and to require
fewer allocations.
* bootstrap (modules): Add dirname-lgpl.
* .gnulib: Update submodule to the latest.

* src/util/util.c (virExecWithHook): Free argv_str string before
returning upon failure to allocate space for environment.

* src/util/cgroup.c (virCgroupDetectPlacement): Close the mapping
FILE* also upon error.

* src/util/cgroup.c (virCgroupCpuSetInherit) [HAVE_MNTENT_H]:
Don't leak CPU-set inheritance value strings.

Similar fix as previous one but for fork() usage when creating
a file or directory

* src/util/util.c: virLogLock() and virLogUnlock() around fork()
  in virFileCreate() and virDirCreateSimple()

Ad pointed out by Dan Berrange:
So if some thread in libvirtd is currently executing a logging call,
while another thread calls virExec(), that other thread no longer
exists in the child, but its lock is never released. So when the
child then does virLogReset() it deadlocks.

The only way I see to address this, is for the parent process to call
virLogLock(), immediately before fork(), and then virLogUnlock()
afterwards in both parent & child. This will ensure that no other
thread
can be holding the lock across fork().

* src/util/logging.[ch] src/libvirt_private.syms: export virLogLock() and
  virLogUnlock()
* src/util/util.c: lock just before forking and unlock just after - in
  both parent and child.

* src/util/util.c (virGetUserID, virGetGroupID): In the unlikely event
that sysconf(_SC_GETPW_R_SIZE_MAX) fails, don't use -1 as the size in
the subsequent allocation.

* src/util/json.c (virJSONValueFree): Free the "value" pointer, too.

Signed-off-by: NChris Lalancette <clalance@redhat.com>

On RHEL-5 the qemu-kvm binary is located in /usr/libexec.
To reduce confusion for people trying to run upstream libvirt
on RHEL-5 machines, make the qemu driver look in /usr/libexec
for the qemu-kvm binary.

To make this work, I modified virFindFileInPath to handle an
absolute path correctly.  I also ran into an issue where
NULL was sometimes being passed for the file parameter
to virFindFileInPath; it didn't crash prior to this patch
since it was building paths like /usr/bin/(null).  This
is non-standard behavior, though, so I added a NULL
check at the beginning.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

* src/util/util.c (virGetUserEnt): In the unlikely event that
sysconf(_SC_GETPW_R_SIZE_MAX) fails, don't use -1 as the size in
the subsequent allocation.

* src/util/pci.c (pciDeviceDownstreamLacksACS): Fix a typo
that rendered a subexpression always false.

* src/util/hostusb.c (usbSysReadFile): Rename labels s/error/cleanup/
(usbFindBusByVendor): Likewise.  And closedir only if non-NULL.

virFileMakePath is a recursive function that was creates a buffer
PATH_MAX bytes long for each recursion (one recursion for each element
in the path). This changes it to have no buffers on the stack, and to
allocate just one buffer total, no matter how many elements are in the
path. Because the modified algorithm requires a char* to be passed in
rather than const char *, it is now 2 functions - a toplevel API
function that remains identical in function, and a 2nd helper function
called for the recursions, which 1) doesn't allocate anything, and 2)
takes a char* arg, so it can modify the contents.
* src/util/util.c: rewrite virFileMakePath

* src/util/json.c, src/util/json.h: Declare returned strings
  to be const
* src/qemu/qemu_monitor.c: Wire up JSON mode for qemuMonitorGetPtyPaths
* src/qemu/qemu_monitor_json.c, src/qemu/qemu_monitor_json.h: Fix
  const correctness. Add missing error message in the function
  qemuMonitorJSONGetAllPCIAddresses. Add implementation of the
  qemuMonitorGetPtyPaths function calling 'query-chardev'.

* src/util/hostusb.c (usbGetDevice): Free "dev" when returning NULL.

* src/util/hostusb.c (usbFindBusByVendor): Don't leak a DIR buffer
and file descriptor.

Certain hypervisors (like qemu/kvm) map the PCI bar(s) on
the host when doing device passthrough.  This can lead to a race
condition where the hypervisor is still cleaning up the device while
libvirt is trying to re-attach it to the host device driver.  To avoid
this situation, we look through /proc/iomem, and if the hypervisor is
still holding onto the bar (denoted by the string in the matcher variable),
then we can wait around a bit for that to clear up.

v2: Thanks to review by DV, make sure we wait the full timeout per-device
Signed-off-by: NChris Lalancette <clalance@redhat.com>

The patches to add ACS checking to PCI device passthrough
introduced a bug.  With the current code, if you try to
passthrough a device on the root bus (i.e. bus 0), then
it denies the passthrough.  This is because the code in
pciDeviceIsBehindSwitchLackingACS() to check for a parent
device doesn't take into account the possibility of the
root bus.  If we are on the root bus, it means we
legitimately can't find a parent, and it also means that
we don't have to worry about whether ACS is enabled.
Therefore return 0 (indicating we don't lack ACS) from
pciDeviceIsBehindSwitchLackingACS().
Signed-off-by: NChris Lalancette <clalance@redhat.com>

* src/util/uuid.c: extend virUUIDParse to allow leading and trailing
  spaces in UUIDs

These functions create a new file or directory with the given
uid/gid. If the flag VIR_FILE_CREATE_AS_UID is given, they do this by
forking a new process, calling setuid/setgid in the new process, and
then creating the file. This is better than simply calling open then
fchown, because in the latter case, a root-squashing nfs server would
create the new file as user nobody, then refuse to allow fchown.

If VIR_FILE_CREATE_AS_UID is not specified, the simpler tactic of
creating the file/dir, then chowning is is used. This gives better
results in cases where the parent directory isn't on a root-squashing
NFS server, but doesn't give permission for the specified uid/gid to
create files. (Note that if the fork/setuid method fails to create the
file due to access privileges, the parent process will make a second
attempt using this simpler method.)

If the bit VIR_FILE_CREATE_ALLOW_EXIST is set in the flags, an
existing file/directory will not cause an error; in this case, the
function will simply set the permissions of the file/directory to
those requested. If VIR_FILE_CREATE_ALLOW_EXIST is not specified, an
existing file/directory is considered (and reported as) an error.

Return from both of these functions is 0 on success, or the value of
errno if there was a failure.

* src/util/util.[ch]: add the 2 new util functions

* src/util/util.[ch]: similar to virExecWithHook, but waits for child to
  exit. Useful for doing things like setuid after the fork but before the
  exec.

* src/util/logging.c (virLogMessage): Include "ignore-value.h".
Use it to ignore the return value of safewrite.
Use STDERR_FILENO, rather than "2".
* bootstrap (modules): Add ignore-value.
* gnulib: Update to latest, for ignore-value that is now LGPLv2+.