slog()'s function comment advises to use QERR_QGA_LOGGING_DISABLED.
This macro never existed. The reference got added in commit
e3d4d25206 "guest agent: add guest agent RPCs/commands" along with
QERR_QGA_LOGGING_FAILED, so maybe that one was meant. However,
QERR_QGA_LOGGING_FAILED was never actually used, and was removed in
commit d73f0beadb "qerror.h: Remove unused error classes".
Drop the dangling reference.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230207075115.1525-9-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
The has_FOO for pointer-valued FOO are redundant, except for arrays.
They are also a nuisance to work with. Recent commit "qapi: Start to
elide redundant has_FOO in generated C" provided the means to elide
them step by step. This is the step for qga/qapi-schema.json.
Said commit explains the transformation in more detail. The invariant
violations mentioned there do not occur here.
Cc: Michael Roth <michael.roth@amd.com>
Cc: Konstantin Kostiuk <kkostiuk@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221104160712.3005652-30-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Since the introduction of guest-exec in/out/err redirections in commit
a1853dca74 ("qga: guest-exec simple stdin/stdout/stderr redirection"),
some execution state variables are handled with atomic ops. However,
there are no threads involved in this code (and glib sources are
dispatched in the same thread), and no other obvious reason to use them.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-40-marcandre.lureau@redhat.com>
The function is specific to qemu-ga, no need to share it in QEMU.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Message-Id: <20220420132624.2439741-32-marcandre.lureau@redhat.com>
GLib g_get_real_time() is an alternative to gettimeofday() which allows
to simplify our code.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20220307070401.171986-4-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
g_new(T, n) is neater than g_malloc(sizeof(T) * n). It's also safer,
for two reasons. One, it catches multiplication overflowing size_t.
Two, it returns T * rather than void *, which lets the compiler catch
more type errors.
This commit only touches allocations with size arguments of the form
sizeof(T).
Patch created mechanically with:
$ spatch --in-place --sp-file scripts/coccinelle/use-g_new-etc.cocci \
--macro-file scripts/cocci-macro-file.h FILES...
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20220315144156.1595462-4-armbru@redhat.com>
Reviewed-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
If the guest command fails to be spawned, then we would leak the decoded
base64 input used for the command's stdin feed.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: AlexChen <alex.chen@huawei.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
*fix 80+ char violation while we're here
*fix w32 build breakage from changing INVALID_SET_FILE_POINTER
definition from a cast to a subtraction
Signed-off-by: Michael Roth <michael.roth@amd.com>
Anywhere we create a list of just one item or by prepending items
(typically because order doesn't matter), we can use
QAPI_LIST_PREPEND(). But places where we must keep the list in order
by appending remain open-coded until later patches.
Note that as a side effect, this also performs a cleanup of two minor
issues in qga/commands-posix.c: the old code was performing
new = g_malloc0(sizeof(*ret));
which 1) is confusing because you have to verify whether 'new' and
'ret' are variables with the same type, and 2) would conflict with C++
compilation (not an actual problem for this file, but makes
copy-and-paste harder).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20201113011340.463563-5-eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
[Straightforward conflicts due to commit a8aa94b5f8 "qga: update
schema for guest-get-disks 'dependents' field" and commit a10b453a52
"target/mips: Move mips_cpu_add_definition() from helper.c to cpu.c"
resolved. Commit message tweaked.]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
clang's C11 atomic_fetch_*() functions only take a C11 atomic type
pointer argument. QEMU uses direct types (int, etc) and this causes a
compiler error when a QEMU code calls these functions in a source file
that also included <stdatomic.h> via a system header file:
$ CC=clang CXX=clang++ ./configure ... && make
../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid)
Avoid using atomic_*() names in QEMU's atomic.h since that namespace is
used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h
and <stdatomic.h> can co-exist. I checked /usr/include on my machine and
searched GitHub for existing "qatomic_" users but there seem to be none.
This patch was generated using:
$ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \
sort -u >/tmp/changed_identifiers
$ for identifier in $(</tmp/changed_identifiers); do
sed -i "s%\<$identifier\>%q$identifier%g" \
$(git grep -I -l "\<$identifier\>")
done
I manually fixed line-wrap issues and misaligned rST tables.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200923105646.47864-1-stefanha@redhat.com>
Problem with g_get_host_name() is that on the first call it saves
the hostname into a global variable and from then on, every
subsequent call returns the saved hostname. Even if the hostname
changes. This doesn't play nicely with guest agent, because if
the hostname is acquired before the guest is set up (e.g. on the
first boot, or before DHCP) we will report old, invalid hostname.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1845127
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
On [*] Daniel Berrangé commented:
The QEMU guest agent protocol is not sensible way to access huge
files inside the guest. It requires the inefficient process of
reading the entire data into memory than duplicating it again in
base64 format, and then copying it again in the JSON serializer /
monitor code.
For arbitrary general purpose file access, especially for large
files, use a real file transfer program or use a network block
device, not the QEMU guest agent.
To avoid bug reports as BZ#1594054 (CVE-2018-12617), follow his
suggestion to put a low, hard limit on "count" in the guest agent
QAPI schema, and don't allow count to be larger than 48 MB.
[*] https://www.mail-archive.com/qemu-devel@nongnu.org/msg693176.html
Fixes: CVE-2018-12617
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1594054
Reported-by: Fakhri Zulkifli <mohdfakhrizulkifli@gmail.com>
Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
*update schema documentation to indicate 48MB limit instead of 10MB
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Extract the common code shared by both POSIX/Win32 implementations.
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
The QAPI struct GuestFileWhence has a comment about how we are
exploiting equivalent values between two different integer types
shared in a union. But C says behavior is undefined on assignments to
overlapping storage when the two types are not the same width, and
indeed, 'int64_t value' and 'enum QGASeek name' are very likely to be
different in width. Utilize a temporary variable to fix things.
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Fixes: 0b4b49387
Fixes: Coverity CID 1421990
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Since 0b69f6f72c "qapi: remove
qmp_unregister_command()", the command list can be declared const.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Damien Hedde <damien.hedde@greensocs.com>
Message-Id: <20200316171824.2319695-1-marcandre.lureau@redhat.com>
[Rebased]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20191205174635.18758-13-vsementsov@virtuozzo.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Per supported platforms doc[1], the various min glib on relevant distros is:
RHEL-7: 2.50.3
Debian (Stretch): 2.50.3
Debian (Jessie): 2.42.1
OpenBSD (Ports): 2.54.3
FreeBSD (Ports): 2.50.3
OpenSUSE Leap 15: 2.54.3
SLE12-SP2: 2.48.2
Ubuntu (Xenial): 2.48.0
macOS (Homebrew): 2.56.0
This suggests that a minimum glib of 2.42 is a reasonable target.
The GLibC compile farm, however, uses Ubuntu 14.04 (Trusty) which only
has glib 2.40.0, and this is needed for testing during merge. Thus an
exception is made to the documented platform support policy to allow for
all three current LTS releases to be supported.
Docker jobs that not longer satisfy this new min version are removed.
[1] https://qemu.weilnetz.de/doc/qemu-doc.html#Supported-build-platforms
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
When pulling in headers that are in the same directory as the C file (as
opposed to one in include/), we should use its relative path, without a
directory.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Move qapi-schema.json to qapi/, so it's next to its modules, and all
files get generated to qapi/, not just the ones generated for modules.
Consistently name the generated files qapi-MODULE.EXT:
qmp-commands.[ch] become qapi-commands.[ch], qapi-event.[ch] become
qapi-events.[ch], and qmp-introspect.[ch] become qapi-introspect.[ch].
This gets rid of the temporary hacks in scripts/qapi/commands.py,
scripts/qapi/events.py, and scripts/qapi/common.py.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180211093607.27351-28-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
[eblake: Fix trailing dot in tpm.c, undo temporary hack for OSX toolchain]
Signed-off-by: Eric Blake <eblake@redhat.com>
This cleanup makes the number of objects depending on qapi/error.h
drop from 1910 (out of 4743) to 1612 in my "build everything" tree.
While there, separate #include from file comment with a blank line,
and drop a useless comment on why qemu/osdep.h is included first.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-5-armbru@redhat.com>
[Semantic conflict with commit 34e304e975 resolved, OSX breakage fixed]
We would like to use a same QObject type to represent numbers, whether
they are int, uint, or floats. Getters will allow some compatibility
between the various types if the number fits other representations.
Add a few more tests while at it.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20170607163635.17635-7-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[parse_stats_intervals() simplified a bit, comment in
test_visitor_in_int_overflow() tidied up, suppress bogus warnings]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Adds a new command `guest-get-timezone` reporting the currently
configured timezone on the system. The information on what timezone is
currently is configured is useful in case of Windows VMs where the
offset of the hardware clock is required to have the same offset. This
can be used for management systems like `oVirt` to detect the timezone
difference and warn administrators of the misconfiguration.
Signed-off-by: Vinzenz Feenstra <vfeenstr@redhat.com>
Reviewed-by: Sameeh Jubran <sameeh@daynix.com>
Tested-by: Sameeh Jubran <sameeh@daynix.com>
* moved stub implementation to end of function for consistency
* document that timezone names are for informational use only.
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Retrieving the guest host name is a very useful feature for virtual management
systems. This information can help to have more user friendly VM access
details, instead of an IP there would be the host name. Also the host name
reported can be used to have automated checks for valid SSL certificates.
virsh # qemu-agent-command F25 '{ "execute": "guest-get-host-name" }'
{"return":{"host-name":"F25.lab.evilissimo.net"}}
Signed-off-by: Vinzenz Feenstra <vfeenstr@redhat.com>
* minor whitespace fix-ups
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
The command registry encapsulates a single command list. Give the
functions using it a parameter instead. Define suitable command lists
in monitor, guest agent and test-qmp-commands.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1488544368-30622-6-git-send-email-armbru@redhat.com>
[Debugging turds buried]
Reviewed-by: Eric Blake <eblake@redhat.com>
The guest client's use of the glib's g_atomic primitives causes newer
GCC's to barf when built on Travis. As QEMU has its own primitives with
well understood semantics we might as well use them.
The use of atomics was a little inconsistent so I've also ensure the
values are correctly set with atomic primitives at the same time.
I also made the usage of bool consistent while I was at it.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20160930213106.20186-12-alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Remove glib.h includes, as it is provided by osdep.h.
This commit was created with scripts/clean-includes.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Yuriy Pudgorodskiy <yur@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
* squashed in g_io_channel_shutdown() to match cleanup paths for
input/output
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Move declarations out of qemu-common.h for functions declared in
utils/ files: e.g. include/qemu/path.h for utils/path.c.
Move inline functions out of qemu-common.h and into new files (e.g.
include/qemu/bcd.h)
Signed-off-by: Veronia Bahaa <veroniabahaa@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Magic constants are a pain to use, especially when we run the
risk that our choice of '1' for QGA_SEEK_CUR might differ from
the host or guest's choice of SEEK_CUR. Better is to use an
enum value, via a qapi alternate type for back-compatibility.
With this,
{"command":"guest-file-seek", "arguments":{"handle":1,
"offset":0, "whence":"cur"}}
becomes a synonym for the older
{"command":"guest-file-seek", "arguments":{"handle":1,
"offset":0, "whence":1}}
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.
This commit was created with scripts/clean-includes.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1454089805-5470-9-git-send-email-peter.maydell@linaro.org
Switch from using g_base64_decode over to qbase64_decode
in order to get error checking of the base64 input data.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This was original behaviour before GLIB gspawn() rework and we rely on
this behaviour.
Signed-off-by: Yuri Pudgorodskiy <yur@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
* add version check (2.33.2) for G_SPAWN_SEARCH_PATH_FROM_ENVP
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
envp == NULL must be passed inside gspawn() if it was not passed with
the command line. Original code inherits environment from the QGA,
which is wrong.
Signed-off-by: Yuri Pudgorodskiy <yur@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Implemented with base64-encoded strings in qga json protocol.
Glib portable GIOChannel is used for data I/O.
Optinal stdin parameter of guest-exec command is now used as
stdin content for spawned subprocess.
If capture-output bool flag is specified, guest-exec redirects out/err
file descriptiors internally to pipes and collects subprocess
output.
Guest-exe-status is modified to return this collected data to requestor
in base64 encoding.
Signed-off-by: Yuri Pudgorodskiy <yur@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
* switch from 'struct GuestIOExecData' to 'GuestIOExecData'
* s/TRUE/true/g, s/FALSE/false/g for gboolean return values
* s/inp_data/input_data/
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
qemu-ga should not exit on guest-file-write to pipe without read end
but proper error code should be returned. The behavior of the
spawned process should be default thus SIGPIPE processing should be
reset to default after fork() but before exec().
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Yuri Pudgorodskiy <yur@virtuozzo.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Guest-exec rewritten in platform-independent style with glib spawn.
Child process is spawn asynchronously and exit status can later
be picked up by guest-exec-status command.
stdin/stdout/stderr of the child now is redirected to /dev/null
Later we will add ability to specify stdin in guest-exec command
and to get collected stdout/stderr with guest-exec-status.
Signed-off-by: Yuri Pudgorodskiy <yur@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
* use g_new0 in place of g_malloc for GuestExec struct
* commit msg spelling fixes
* s/inp-data/input-data
* document capture-input mode as false by default
* use GetProcessId() for pids on w32 instead of casting HANDLE
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
g_new(T, n) is neater than g_malloc(sizeof(T) * n). It's also safer,
for two reasons. One, it catches multiplication overflowing size_t.
Two, it returns T * rather than void *, which lets the compiler catch
more type errors.
This commit only touches allocations with size arguments of the form
sizeof(T). Same Coccinelle semantic patch as in commit b45c03f.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Now we have several qemu-ga commands not returning response on success.
It has been documented in qga/qapi-schema.json already. This patch exposes
the 'success-response' flag by extending 'guest-info' command. With this
change, the clients can handle the command response more flexibly.
Signed-off-by: Mark Wu <wudxw@linux.vnet.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
*fixed up commit subject
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
In the original code, qmp_get_command_list is used to construct
a list of all commands' name. To get the information of all qga
commands, it traverses the name list and search the command info
with its name. So it can cause O(n^2) in the number of commands.
This patch adds an interface to traverse the qmp command list by
QmpCommand to replace qmp_get_command_list. It can decrease the
complexity from O(n^2) to O(n).
Signed-off-by: Mark Wu <wudxw@linux.vnet.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
*fix up commit subject
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
I figure it's freed somewhere deep down in QAPI, with g_free().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Previously qemu-ga version was defined seperately. Since it is aligned
with QEMU releases, use QEMU_VERSION instead. This also implies the
version bump for 1.1[-rcN] release of qemu-ga.
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Acked-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
guest-sync leaves it as an exercise to the user as to how to reliably
obtain the response to guest-sync if the client had previously read in a
partial response (due qemu-ga previously being restarted mid-"sentence"
due to reboot, forced restart, etc).
qemu-ga handles this situation on its end by having a client precede
their guest-sync request with a 0xFF byte (invalid UTF-8), which
qemu-ga/QEMU JSON parsers will treat as a flush event. Thus we can
reliably flush the qemu-ga parser state in preparation for receiving
the guest-sync request.
guest-sync-delimited provides the same functionality for a client: when
a guest-sync-delimited is issued, qemu-ga will precede it's response
with a 0xFF byte that the client can use as an indicator to flush its
buffer/parser state in preparation for reliably receiving the
guest-sync-delimited response.
It is also useful as an optimization for clients, since, after issuing a
guest-sync-delimited, clients can safely discard all stale data read
from the channel until the 0xFF is found.
More information available on the wiki:
http://wiki.qemu.org/Features/QAPI/GuestAgent#QEMU_Guest_Agent_Protocol
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Many of the current RPC implementations are very much POSIX-specific
and require complete re-writes for Windows. There are however a small
set of core guest agent commands that are common to both, and other
commands such as guest-file-* which *may* be portable. So we introduce
commands.c for the latter, and will rename guest-agent-commands.c to
commands-posix.c in a future commit. Windows implementations will go in
commands-win32.c, eventually.
