`dump' watchdog action lets libvirtd to dump the guest when receives a
watchdog event (which probably means a guest crash)

Currently only qemu is supported.

This patch prepares for the next patch.

* 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.

When we get an EOF event on monitor connection, it may be a result of
either crash or graceful shutdown. QEMU which supports async events
(i.e., we are talking to it using JSON monitor) emits SHUTDOWN event on
graceful shutdown. In case we don't get this event by the time monitor
connection is closed, we assume the associated domain crashed.

Currently libvirt doesn't confirm whether the guest has responded to the
disk removal request.  In some cases this can leave the guest with
continued access to the device while the mgmt layer believes that it has
been removed.  With a recent qemu monitor command[1] we can
deterministically revoke a guests access to the disk (on the QEMU side)
to ensure no futher access is permitted.

This patch adds support for the drive_del() command and introduces it
in the disk removal paths.  If the guest is running in a QEMU without this
command we currently explicitly check for unknown command/CommandNotFound
and log the issue.

If QEMU supports the command we issue the drive_del command after we attempt
to remove the device.  The guest may respond and remove the block device
before we get to attempt to call drive_del.  In that case, we explicitly check
for 'Device not found' from the monitor indicating that the target drive
was auto-deleted upon guest responds to the device removal notification.

1. http://thread.gmane.org/gmane.comp.emulators.qemu/84745Signed-off-by: NRyan Harper <ryanh@us.ibm.com>

Currently libvirt doesn't confirm whether the guest has responded to the
disk removal request.  In some cases this can leave the guest with
continued access to the device while the mgmt layer believes that it has
been removed.  With a recent qemu monitor command[1] we can
deterministically revoke a guests access to the disk (on the QEMU side)
to ensure no futher access is permitted.

This patch adds support for the drive_unplug() command and introduces it
in the disk removal paths.  There is some discussion to be had about how
to handle the case where the guest is running in a QEMU without this
command (and the fact that we currently don't have a way of detecting
what monitor commands are available).

Changes since v2:
 - use VIR_ERROR to report when unplug command not found
Changes since v1:
 - return > 0 when command isn't present, < 0 on command failure
 - detect when drive_unplug command isn't present and log error
   instead of failing entire command
Signed-off-by: NRyan Harper <ryanh@us.ibm.com>

The extra data isn't being free()'d for IO error events that have a reason.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

- qemudDomainAttachPciControllerDevice: Don't build "devstr"
  if "-device" of qemu is not available, as "devstr" will only
  be used by "qemuMonitorAddDevice", which depends on "-device"
  argument of qemu is supported.

- "qemudDomainSaveImageOpen": Fix indent problem.

* src/qemu/qemu_driver.c

Commit febc5916 introduced -vga none in
case no video card is included in domain XML. However, old qemu
versions do not support this and such domain cannot be successfully
started.

* .gnulib: Update to latest, for at least a stdint.h fix
* src/storage/storage_driver.c (storageVolumeZeroSparseFile)
(storageWipeExtent): Use better type, although it still triggers
spurious -Wformat warning on MacOS's gcc.

* src/openvz/openvz_conf.c (openvzLoadDomains): Replace unsafe
sscanf with safe direct parsing.
(openvzGetVEID): Avoid lost integer overflow detection.
(openvzAssignUUIDs): Likewise, and detect readdir failure.

popen must be matched with pclose (not fclose), or it will leak
resources.  Furthermore, it is a lousy interface when it comes to
signal handling.  We're much better off using our decent command
wrapper.  Note that virCommand guarantees that VIR_FREE(outbuf) is
both required and safe to call, whether virCommandRun succeeded or
failed.

* src/openvz/openvz_conf.c (openvzLoadDomains, openvzGetVEID):
Replace popen with virCommand usage.

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.

* src/conf/domain_conf.c (virDomainDefParseXML): Prefer sysinfo
uuid over generating one, and if both uuids are present, require
them to be identical.
* src/qemu/qemu_conf.c (qemuBuildSmbiosSystemStr): Allow skipping
the uuid.
(qemudBuildCommandLine): Adjust caller; <smbios mode=host/> must
not use host uuid in place of guest uuid.

* 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.

The log lists things like -smbios type=1,vendor="Red Hat", which
is great for shell parsing, but not so great when you realize that
execve() then passes those literal "" on as part of the command
line argument, such that qemu sets SMBIOS with extra literal quotes.

The eventual addition of virCommand is needed before we have the API
to shell-quote a string representation of a command line, so that the
log can still be pasted into a shell, but without inserting extra
bytes into the execve() arguments.

* src/qemu/qemu_conf.c (qemuBuildSmbiosBiosStr)
(qemuBuildSmbiosSystemStr): Qemu doesn't like quotes around uuid
arguments, and the remaining quotes are passed literally to
smbios, making <smbios mode='host'/> inaccurate.  Removing the
quotes makes the log harder to parse, but that can be fixed later
with virCommand improvements.
* tests/qemuxml2argvdata/qemuxml2argv-smbios.args: 'Fix' test; it
will need fixing again once virCommand learns how to shell-quote a
potential command line.

Humans consider January as month #1, while gmtime_r(3) calls it month #0.

While fixing it, render qemu's rtc parameter with leading zeros, as is more
commonplace.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=660194

* 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)

Two more calls to remote libvirtd have to be surrounded by
qemuDomainObjEnterRemoteWithDriver() and
qemuDomainObjExitRemoteWithDriver() to prevent possible deadlock between
two communicating libvirt daemons.

See commit f0c8e1cb for further details.

virDrvSupportsFeature API is allowed to return -1 on error while all but
one uses of VIR_DRV_SUPPORTS_FEATURE only check for (non)zero return
value. Let's make this macro return zero on error, which is what
everyone expects anyway.

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.

* src/uml/uml_conf.c (umlBuildCommandLineChr)
(umlBuildCommandLine): Rewrite with virCommand.
* src/uml/uml_conf.h (umlBuildCommandLine): Update signature.
* src/uml/uml_driver.c (umlStartVMDaemon): Adjust caller.

* src/qemu/qemu_conf.c (qemudExtractVersionInfo): Check for file
before executing it here, rather than in callers.
(qemudBuildCommandLine): Rewrite with virCommand.
* src/qemu/qemu_conf.h (qemudBuildCommandLine): Update signature.
* src/qemu/qemu_driver.c (qemuAssignPCIAddresses)
(qemudStartVMDaemon, qemuDomainXMLToNative): Adjust callers.

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

Drop unused (and unclosed) errfd and close outfd on exit. Otherwise
polling the running domains with virt-manager let's us quickly run out
of fds.

* src/qemu/qemu_driver.c (though MACROS QEMU_VNC_PORT_MAX, and
QEMU_VNC_PORT_MIN are defined at the beginning, numbers (65535, 5900)
are still used, replace them)

typo in error message, it should be by copy-a-paste
from "qemuSetupDiskPathAllow".

* src/qemu/qemu_driver.c (qemuTeardownDiskPathDeny)

* 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.