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.

Most leaks could only occur on error cleanup paths.

* 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 (sysinf-value): Expand pattern.
* tests/qemuxml2argvdata/qemuxml2argv-smbios.xml: Prefer '' over
"" for attribute values.  Copy real hardware values.
* tests/qemuxml2argvdata/qemuxml2argv-smbios.args: Likewise.

* 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.

"echo" is already in group "virsh", "freecell" and "hostname" are
already in group "host", so remove them from group "domain"

* tools/virsh.c

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

When libvirt-guests is being stopped, I get the following message:
$Running guests on default URI: test-vm
$Suspending guests on default URI...
$Suspending test-vm: /etc/init.d/libvirt-guests: 340: Syntax error: Bad fd
number

* 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.

* tools/virsh.c (cmdRunConsole, cmdConsole): Rename problematic
symbol.
Reported by Justin Clift.

Remove the optional option "group", as cmdHelp should accepts
only one option ("virsh help" supports both command and command
group now, and user rarely uses the options, so it doesn't matter
much for it being longer, :-)

* tools/virsh.c

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.

Now includes information on keyword usage, and provides examples.

* tools/virsh.c (find-storage-pool-sources-as and find-storage-pool-sources
should't be in command group "Domain Management", move them to group
"Storage Pool".

* 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

* docs/internals/command.html.in: New file.
* docs/Makefile.am: Build new docs.
* docs/subsite.xsl: New glue file.
* docs/internals.html.in, docs/sitemap.html.in: Update glue.

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.

* daemon/event.c: Include errno in debug info upon poll() failure

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

This patch allows for using custom scripts instead of /usr/bin/qemu
emulator in domain XML. To do so, one would specify relative path to the
custom script in <emulator/>. The path needs to be relative to
qemuxml2argvdata directory and it will be transparently made absolute in
runtime. The expected command line needs to contain the exact relative
path as was used in domain XML.

The problem is RelaxNG schema for domain XML only allows for absolute
path within <emulator/>. To workaround it, an extra '/' must be added at
the beginning of the path. That is, instead of "./qemu.sh" or
"../emulator/qemu.sh" one would use "/./qemu.sh" or
"/../emulator/qemu.sh". The extra slash is removed before further
processing. I don't like this workaround, it's very ugly but it's the
best option I was able to come up with. Relaxing domain XML schema is
not an option IMO.

Both vendor and topology elements are optional.