virSetUIDGID() sets both the real and effective group and user of the
process, and additionally calls initgroups() to assure that the
process joins all the auxiliary groups that the given uid is a member
of.

There are cases when we want log an error message, and possibly free
some memory as part of the cleanup, while still preserving errno for a
caller, but the functions that log errors, and virFree (VIR_FREE) make
system calls that will clear errno. This patch preserves errno during
those most basic functions (corresponding to virReportSystemError(),
virReportOOMError(), networkReportError(), etc, as well as
virStrError()). It does *not preserve errno across calls to higher
level items such as virDispatchError(), as it's assumed the caller is
all finished with any need for errno by the time it dispatches the
error.

All of the iptables functions eventually call down to a single
bottom-level function, and fortunately, ip6tables syntax (for all the
args that we use) is identical to iptables format (except the
addresses), so all we need to do is:

1) Get an address family down to the lowest level function in each
   case, either implied through an address, or explicitly when no
   address is in the parameter list, and

2) At the lowest level, just decide whether to call "iptables" or
   "ip6tables" based on the family.

The location of the ip6tables binary is determined at build time by
autoconf. If a particular target system happens to not have ip6tables
installed, any attempts to run it will generate an error, but that
won't happen unless someone tries to define an IPv6 address for a
network. This is identical behavior to IPv4 addresses and iptables.

brSetInetAddress can only set a single IP address on the bridge, and
uses a method (ioctl(SIOCSETIFADDR)) that only works for IPv4. Replace
it and brSetInetNetmask with a single function that uses the external
"ip addr add" command to add an address/prefix to the interface - this
supports IPv6, and allows adding multiple addresses to the interface.

Although it isn't currently used in the code, we also add a
brDelInetAddress for completeness' sake.

Also, while we're modifying bridge.c, we change brSetForwardDelay and
brSetEnableSTP to use the new virCommand API rather than the
deprecated virRun, and also log an error message in bridge_driver.c if
either of those fail (previously the failure would be completely
silent).

IPv6 will use prefix exclusively, and IPv4 will also optionally be
able to use it, and the iptables functions really need a prefix
anyway, so use the new virNetworkDefPrefix() function to send prefixes
into iptables functions instead of netmasks.

Also, in a couple places where a netmask is actually needed, use the
new private API function for it rather than getting it directly. This
will allow for cases where no netmask or prefix is specified (it
returns the default for the current class of network.)

virSocketPrefixToNetmask: Given a 'prefix', which is the number of 1
bits in a netmask, fill in a virSocketAddr object with a netmask as an
IP address (IPv6 or IPv4).

virSocketAddrMask: Mask off the host bits in one virSocketAddr
according to the netmask in another virSocketAddr.

virSocketAddrMaskByPrefix, Mask off the host bits in a virSocketAddr
according to a prefix (number of 1 bits in netmask).

VIR_SOCKET_FAMILY: return the family of a virSocketAddr

I began noticing a race when reserving VNC ports as described here

https://www.redhat.com/archives/libvir-list/2010-November/msg00379.html

Turns out that we were not initializing the size field of bitmap
struct when allocating the bitmap.  This subsequently caused
virBitmapSetBit() to fail since bitmap->size is 0, hence we never
actually reserved the port.

* src/util/command.c (virCommandRun): Don't capture output on
daemons.
* tests/commandtest.c (test18): Expose the bug.
Reported by Laine Stump.

Remove superfluous ": %s" suffix from the error message.

* daemon/libvirtd.c (qemudStartWorker, qemudStartEventLoop): Avoid
leaking pthread_attr resources.
* src/util/threads-pthread.c (virThreadCreate): Likewise.

* src/util/sysinfo.c (virSysinfoRead): Use virCommand instead of
virExec.

* src/util/sysinfo.c: Indentation and () fixups.

Allows compilation, but no creation of child processes yet.  Take it
one step at a time.

* src/util/util.c (virExecWithHook) [WIN32]: New dummy function.
* src/libvirt_private.syms: Export it.

Current code does not pass VM mac address to a 802.1Qbh direct attach
interface using IFLA_VF_MAC.  This patch adds support in macvtap code to
send IFLA_VF_MAC netlink request during port profile association on a
802.1Qbh interface.

Stefan Cc'ed for comments because this patch changes a condition for
802.1Qbg

802.1Qbh support for IFLA_VF_MAC in enic driver has been posted and is
pending acceptance at http://marc.info/?l=linux-netdev&m=129185244410557&w=2

* src/util/command.h (virCommandAddArgBuffer)
(virCommandAddEnvBuffer): New prototypes.
* src/util/command.c (virCommandAddArgBuffer)
(virCommandAddEnvBuffer): Implement them.
* src/libvirt_private.syms (command.h): Export them.
* src/qemu/qemu_conf.c (qemudBuildCommandLine): Use them, plugging
a memory leak on rbd_hosts in the process.

* src/util/util.c (__virExec): Don't use FD_ISSET on out-of-bounds fd.

* src/util/command.c (virCommandFree): Free data from
virCommandSetInputBuffer.

* src/util/threadpool.c, src/util/threadpool.h: Thread pool
  implementation
* src/Makefile.am: Build thread pool
* src/libvirt_private.syms: Export public functions

* src/util/command.c (virCommandRun): Fix yesterday's regression
on logging, and avoid leaking log-only output captures.
Reported by Hu Tao.

Guarantee that outbuf/errbuf are allocated on success, even if to the
empty string.  Caller always has to free the result, and empty output
check requires checking if *outbuf=='\0'.  Makes the API easier to use
safely.  Failure is best effort allocation (some paths, like
out-of-memory, cannot allocate a buffer, but most do), so caller must
free buffer on failure.

* docs/internals/command.html.in: Update documentation.
* src/util/command.c (virCommandSetOutputBuffer)
(virCommandSetErrorBuffer, virCommandProcessIO) Guarantee empty
string on no output.
* tests/commandtest.c (test17): New test.

* docs/internals/command.html.in: Better documentation of buffer
vs. fd considerations.
* src/util/command.c (virCommandRunAsync): Reject raw execution
with string io.
(virCommandRun): Reject execution with user-specified fds not
visiting a regular file.

* src/util/command.c (virCommandAddEnvString): Remove duplicate
code.
(virCommandToString, virCommandRun, virCommandRunAsync)
(virCommandWait): Report NULL command as ENOMEM, not invalid
usage.
Reported by Jiri Denemark.

* docs/schemas/domain.rng (sysinfo-system-name): Also allow
family.
* src/util/sysinfo.h (struct _virSysinfoDef): Add system_family.
* src/conf/domain_conf.c (virSysinfoParseXML)
(virDomainSysinfoDefFormat): Support it.
* src/util/sysinfo.c (virSysinfoDefFree, virSysinfoRead): Likewise.
* src/qemu/qemu_conf.c (qemuBuildSmbiosSystemStr): Likewise.
* tests/qemuxml2argvdata/qemuxml2argv-smbios.xml: Adjust test.
* tests/qemuxml2argvdata/qemuxml2argv-smbios.args: Likewise.

* src/util/threads.h (virThreadID): New prototype.
* src/util/threads-pthread.c (virThreadID): New function.
* src/util/threads-win32.c (virThreadID): Likewise.
* src/libvirt_private.syms (threads.h): Export it.
* daemon/event.c (virEventInterruptLocked): Use it to avoid
warning on BSD systems.

"virCommandRun": if "cmd->outbuf" or "cmd->errbuf" is NULL,
libvirtd will be crashed when trying to start a qemu domain
(which invokes "virCommandRun"), it caused by we try to use
"*cmd->outbuf" and "*cmd->errbuf" regardless of cmd->outbuf
or cmd->errbuf is NULL.

* src/util/command.c (virCommandRun)

As this symbols are exported independent from WITH_MACVTAP.

This patch adds a mode_t parameter to virFileWriteStr().
If mode is different from 0, virFileWriteStr() will try
to create the file if it doesn't exist.

* src/util/util.h (virFileWriteStr): Alter signature.
* src/util/util.c (virFileWriteStr): Allow file creation.
* src/network/bridge_driver.c (networkEnableIpForwarding)
(networkDisableIPV6): Adjust clients.
* src/node_device/node_device_driver.c
(nodeDeviceVportCreateDelete): Likewise.
* src/util/cgroup.c (virCgroupSetValueStr): Likewise.
* src/util/pci.c (pciBindDeviceToStub, pciUnBindDeviceFromStub):
Likewise.

This proof of concept shows how two existing uses of virExec
and virRun can be ported to the new virCommand APIs, and how
much simpler the code becomes

This introduces a new set of APIs in src/util/command.h
to use for invoking commands. This is intended to replace
all current usage of virRun and virExec variants, with a
more flexible and less error prone API.

* src/util/command.c: New file.
* src/util/command.h: New header.
* src/Makefile.am (UTIL_SOURCES): Build it.
* src/libvirt_private.syms: Export symbols internally.
* tests/commandtest.c: New test.
* tests/Makefile.am (check_PROGRAMS): Run it.
* tests/commandhelper.c: Auxiliary program.
* tests/commanddata/test2.log - test15.log: New expected outputs.
* cfg.mk (useless_free_options): Add virCommandFree.
(msg_gen_function): Add virCommandError.
* po/POTFILES.in: New translation.
* .x-sc_avoid_write: Add exemption.
* tests/.gitignore: Ignore new built file.

* src/util/util.h (virVasprintf): New declaration.
* src/util/util.c (virVasprintf): New function.
(virAsprintf): Use it.
* src/util/virtaudit.c (virAuditSend): Likewise.
* src/libvirt_private.syms: Export it.
* cfg.mk (sc_prohibit_asprintf): Also prohibit vasprintf.
* .x-sc_prohibit_asprintf: Add exemption.

* src/util/util.c (saferead): Fix return type.
(safewrite): Fix indentation.

The logging setup requires const char * strings, but the
virLogSetFromEnv() strdup's the env variables, thus causing
a memory leak

* src/util/logging.c: Avoid strdup'ing env variables

* src/qemu/qemu_driver.c (qemudShutdown): Free all strings and the
ebtables structure.
* src/libvirt_private.syms (ebtablesContextFree): Export missing
symbol.
* src/util/ebtables.c (ebtablesContextFree): Allow early exit.

The arguments passed to the thread function must be allocated on
the heap, rather than the stack, since it is possible for the
spawning thread to continue before the new thread runs at all.
In such a case, it is possible that the area of stack where the
thread args were stored is overwritten.

* src/util/threads-pthread.c, src/util/threads-win32.c: Allocate
  thread arguments on the heap

Use macvtap specific functions depending on WITH_MACVTAP.

Use #if instead of #ifdef to check for WITH_MACVTAP, because
WITH_MACVTAP is always defined with value 0 or 1.

Also export virVMOperationType{To|From}String unconditional,
because they are used unconditional in the domain config code.

This patch introduces the usage of the pre-associate state of the IEEE 802.1Qbg standard on incoming VM migration on the target host. It is in response to bugzilla entry 632750.

https://bugzilla.redhat.com/show_bug.cgi?id=632750

For being able to differentiate the exact reason as to why a macvtap device is being created, either due to a VM creation or an incoming VM migration, I needed to pass that reason as a parameter from wherever qemudStartVMDaemon is being called in order to determine whether to send an ASSOCIATE (VM creation) or a PRE-ASSOCIATE (incoming VM migration) towards lldpad.

I am also fixing a problem with the virsh domainxml-to-native call on the way.

Gerhard successfully tested the patch with a recent blade network 802.1Qbg-compliant switch.

The patch should not have any side-effects on the 802.1Qbh support in libvirt, but Roopa (cc'ed) may want to verify this.

This reverts commit

 Log all errors at level INFO to stop polluting syslog
 04bd0360.

and makes virRaiseErrorFull() log errors at debug priority
when called from inside libvirtd. This stops libvirtd from
polluting it's own log with client errors at error priority
that'll be reported and logged on the client side anyway.