Not all backends are able to switch gcontext. Those backends cannot
drive a OOB monitor (the monitor would then be blocking on main
thread).
For example, ringbuf, spice, or more esoteric input chardevs like
braille or MUX.
We already forbid MUX because not all frontends are ready to run outside
main loop. Replace that by a context-switching feature check.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20181205203737.9011-5-marcandre.lureau@redhat.com>
[Error condition simplified, commit message adjusted accordingly]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Chardev backends may not handle safely IO events from concurrent
threads (may not handle I/O events from concurrent threads safely,
only the write path is since commit >
9005b2a758). Better to wake up the
chardev from the monitor IO thread if it's being used as the chardev
context.
Unify code paths by using a BH in all cases.
Drop the now redundant aio_notify() call.
Clean up control flow not to rely on mon->use_io_thread implying
monitor_is_qmp(mon).
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20181205203737.9011-3-marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
The function were not named with "mon_iothread", or following the AIO
vs GMainContext distinction. Inline them instead.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20181205203737.9011-2-marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Commit d32749deb6 moved the call to monitor_init_globals()
to before os_daemonize(), making it an unsuitable place to
spawn the monitor iothread as it won't be inherited over the
fork() in os_daemonize().
We now spawn the thread the first time we instantiate a
monitor which actually has use_io_thread == true.
Instantiation of monitors happens only after os_daemonize().
We still need to create the qmp_dispatcher_bh when not using
iothreads, so this now still happens in
monitor_init_globals().
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Fixes: d32749deb6 ("monitor: move init global earlier")
Message-Id: <20180925081507.11873-3-w.bumiller@proxmox.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: Peter Xu <peterx@redhat.com>
[This fixes a crash on shutdown with --daemonize]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
monitor_resume() and monitor_suspend() both want to
"kick" the I/O thread if it is there, but in
monitor_suspend() lacked the use_io_thread flag condition.
This is required when we later only spawn the thread on
first use.
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180925081507.11873-2-w.bumiller@proxmox.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
When we implemented per-vCPU TCG contexts, we forgot to also
distribute the tcg_time counter, which has remained as a global
accessed without any serialization, leading to potentially missed
counts.
Fix it by distributing the field over the TCG contexts, embedding
it into TCGProfile with a field called "cpu_exec_time", which is more
descriptive than "tcg_time". Add a function to query this value
directly, and for completeness, fill in the field in
tcg_profile_snapshot, even though its callers do not use it.
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <20181010144853.13005-5-cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
qdev_device_help() is used from command line "-device help", or from
HMP "device_add". If used from command line, print help to stdout
(it is only printed on explicit demand).
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
When typing 'help' followed by an unknown command, QEMU will
not print anything to the command line to let the user know
they typed a bad command. Let's fix this by printing a message
to the monitor when this happens. For example:
(qemu) help xyz
unknown command: 'xyz'
Reported-by: Stefan Zimmermann <stzi@linux.ibm.com>
Signed-off-by: Collin Walling <walling@linux.ibm.com>
Message-Id: <1532115624-27568-1-git-send-email-walling@linux.ibm.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
There is no need for per-command need_resume granularity, it should
resume after running an non-oob command on oob-disabled monitor.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180829134043.31706-5-marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This reverts commit abe3cd0ff7.
There is no need to add an additional queue to send the reply to the
IOThread, because QMP response is thread safe, and chardev write path
is thread safe. It will schedule the watcher in the associated
IOThread.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180829134043.31706-4-marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
A chardev may stop trying to write if the associated can_read()
callback returned 0. This happens when the monitor is suspended.
The frontend is supposed to call qemu_chr_fe_accept_input() when it is
ready to accept data again.
An issue was observed with a spice port: pending commands may be
delayed, as the chardev is not flushed. Most chardev don't use the
accept_input() callback, and instead check regularly if they can
write. The ones that do use it are braille, mux, msmouse,
spice (abstract), spicevmc, spiceport, wctablet.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180817173752.19136-1-marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
The generated qapi_event_send_FOO() take an Error ** argument. They
can't actually fail, because all they do with the argument is passing it
to functions that can't fail: the QObject output visitor, and the
@qmp_emit callback, which is either monitor_qapi_event_queue() or
event_test_emit().
Drop the argument, and pass &error_abort to the QObject output visitor
and @qmp_emit instead.
Suggested-by: Eric Blake <eblake@redhat.com>
Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180815133747.25032-4-peterx@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message rewritten, update to qapi-code-gen.txt corrected]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
When we reach monitor_qmp_setup_handlers_bh() we must be using the
IOThread then, so no need to check against it any more. Instead, we
assert.
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180815133747.25032-2-peterx@redhat.com>
[Insufficiently useful comment dropped]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
The JSON parser has three public headers, json-lexer.h, json-parser.h,
json-streamer.h. They all contain stuff that is of no interest
outside qobject/json-*.c.
Collect the public interface in include/qapi/qmp/json-parser.h, and
everything else in qobject/json-parser-int.h.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-54-armbru@redhat.com>
The callback to consume JSON values takes QObject *json, Error *err.
If both are null, the callback is supposed to make up an error by
itself. This sucks.
qjson.c's consume_json() neglects to do so, which makes
qobject_from_json() null instead of failing. I consider that a bug.
The culprit is json_message_process_token(): it passes two null
pointers when it runs into a lexical error or a limit violation. Fix
it to pass a proper Error object then. Update the callbacks:
* monitor.c's handle_qmp_command(): the code to make up an error is
now dead, drop it.
* qga/main.c's process_event(): lumps the "both null" case together
with the "not a JSON object" case. The former is now gone. The
error message "Invalid JSON syntax" is misleading for the latter.
Improve it to "Input must be a JSON object".
* qobject/qjson.c's consume_json(): no update; check-qjson
demonstrates qobject_from_json() now sets an error on lexical
errors, but still doesn't on some other errors.
* tests/libqtest.c's qmp_response(): the Error object is now reliable,
so use it to improve the error message.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-40-armbru@redhat.com>
The classical way to structure parser and lexer is to have the client
call the parser to get an abstract syntax tree, the parser call the
lexer to get the next token, and the lexer call some function to get
input characters.
Another way to structure them would be to have the client feed
characters to the lexer, the lexer feed tokens to the parser, and the
parser feed abstract syntax trees to some callback provided by the
client. This way is more easily integrated into an event loop that
dispatches input characters as they arrive.
Our JSON parser is kind of between the two. The lexer feeds tokens to
a "streamer" instead of a real parser. The streamer accumulates
tokens until it got the sequence of tokens that comprise a single JSON
value (it counts curly braces and square brackets to decide). It
feeds those token sequences to a callback provided by the client. The
callback passes each token sequence to the parser, and gets back an
abstract syntax tree.
I figure it was done that way to make a straightforward recursive
descent parser possible. "Get next token" becomes "pop the first
token off the token sequence". Drawback: we need to store a complete
token sequence. Each token eats 13 + input characters + malloc
overhead bytes.
Observations:
1. This is not the only way to use recursive descent. If we replaced
"get next token" by a coroutine yield, we could do without a
streamer.
2. The lexer reports errors by passing a JSON_ERROR token to the
streamer. This communicates the offending input characters and
their location, but no more.
3. The streamer reports errors by passing a null token sequence to the
callback. The (already poor) lexical error information is thrown
away.
4. Having the callback receive a token sequence duplicates the code to
convert token sequence to abstract syntax tree in every callback.
5. Known bug: the streamer silently drops incomplete token sequences.
This commit rectifies 4. by lifting the call of the parser from the
callbacks into the streamer. Later commits will address 3. and 5.
The lifting removes a bug from qjson.c's parse_json(): it passed a
pointer to a non-null Error * in certain cases, as demonstrated by
check-qjson.c.
json_parser_parse() is now unused. It's a stupid wrapper around
json_parser_parse_err(). Drop it, and rename json_parser_parse_err()
to json_parser_parse().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-35-armbru@redhat.com>
Spotted by ASAN, during make check...
Direct leak of 40 byte(s) in 1 object(s) allocated from:
#0 0x7f8e27262c48 in malloc (/lib64/libasan.so.5+0xeec48)
#1 0x7f8e26a5f3c5 in g_malloc (/lib64/libglib-2.0.so.0+0x523c5)
#2 0x555ab67078a8 in qstring_from_str /home/elmarco/src/qq/qobject/qstring.c:67
#3 0x555ab67071e4 in qstring_new /home/elmarco/src/qq/qobject/qstring.c:24
#4 0x555ab6713fbf in qstring_from_escaped_str /home/elmarco/src/qq/qobject/json-parser.c:144
#5 0x555ab671738c in parse_literal /home/elmarco/src/qq/qobject/json-parser.c:506
#6 0x555ab67179c3 in parse_value /home/elmarco/src/qq/qobject/json-parser.c:569
#7 0x555ab6715123 in parse_pair /home/elmarco/src/qq/qobject/json-parser.c:306
#8 0x555ab6715483 in parse_object /home/elmarco/src/qq/qobject/json-parser.c:357
#9 0x555ab671798b in parse_value /home/elmarco/src/qq/qobject/json-parser.c:561
#10 0x555ab6717a6b in json_parser_parse_err /home/elmarco/src/qq/qobject/json-parser.c:592
#11 0x555ab4fd4dcf in handle_qmp_command /home/elmarco/src/qq/monitor.c:4257
#12 0x555ab6712c4d in json_message_process_token /home/elmarco/src/qq/qobject/json-streamer.c:105
#13 0x555ab67e01e2 in json_lexer_feed_char /home/elmarco/src/qq/qobject/json-lexer.c:323
#14 0x555ab67e0af6 in json_lexer_feed /home/elmarco/src/qq/qobject/json-lexer.c:373
#15 0x555ab6713010 in json_message_parser_feed /home/elmarco/src/qq/qobject/json-streamer.c:124
#16 0x555ab4fd58ec in monitor_qmp_read /home/elmarco/src/qq/monitor.c:4337
#17 0x555ab6559df2 in qemu_chr_be_write_impl /home/elmarco/src/qq/chardev/char.c:175
#18 0x555ab6559e95 in qemu_chr_be_write /home/elmarco/src/qq/chardev/char.c:187
#19 0x555ab6560127 in fd_chr_read /home/elmarco/src/qq/chardev/char-fd.c:66
#20 0x555ab65d9c73 in qio_channel_fd_source_dispatch /home/elmarco/src/qq/io/channel-watch.c:84
#21 0x7f8e26a598ac in g_main_context_dispatch (/lib64/libglib-2.0.so.0+0x4c8ac)
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180809114417.28718-4-marcandre.lureau@redhat.com>
[Screwed up in commit b27314567d]
Cc: qemu-stable@nongnu.org
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
With a Spice port chardev, it is possible to reenter
monitor_qapi_event_queue() (when the client disconnects for
example). This will dead-lock on monitor_lock.
Instead, use some TLS variables to check for recursion and queue the
events.
Fixes:
(gdb) bt
#0 0x00007fa69e7217fd in __lll_lock_wait () at /lib64/libpthread.so.0
#1 0x00007fa69e71acf4 in pthread_mutex_lock () at /lib64/libpthread.so.0
#2 0x0000563303567619 in qemu_mutex_lock_impl (mutex=0x563303d3e220 <monitor_lock>, file=0x5633036589a8 "/home/elmarco/src/qq/monitor.c", line=645) at /home/elmarco/src/qq/util/qemu-thread-posix.c:66
#3 0x0000563302fa6c25 in monitor_qapi_event_queue (event=QAPI_EVENT_SPICE_DISCONNECTED, qdict=0x56330602bde0, errp=0x7ffc6ab5e728) at /home/elmarco/src/qq/monitor.c:645
#4 0x0000563303549aca in qapi_event_send_spice_disconnected (server=0x563305afd630, client=0x563305745360, errp=0x563303d8d0f0 <error_abort>) at qapi/qapi-events-ui.c:149
#5 0x00005633033e600f in channel_event (event=3, info=0x5633061b0050) at /home/elmarco/src/qq/ui/spice-core.c:235
#6 0x00007fa69f6c86bb in reds_handle_channel_event (reds=<optimized out>, event=3, info=0x5633061b0050) at reds.c:316
#7 0x00007fa69f6b193b in main_dispatcher_self_handle_channel_event (info=0x5633061b0050, event=3, self=0x563304e088c0) at main-dispatcher.c:197
#8 0x00007fa69f6b193b in main_dispatcher_channel_event (self=0x563304e088c0, event=event@entry=3, info=0x5633061b0050) at main-dispatcher.c:197
#9 0x00007fa69f6d0833 in red_stream_push_channel_event (s=s@entry=0x563305ad8f50, event=event@entry=3) at red-stream.c:414
#10 0x00007fa69f6d086b in red_stream_free (s=0x563305ad8f50) at red-stream.c:388
#11 0x00007fa69f6b7ddc in red_channel_client_finalize (object=0x563304df2360) at red-channel-client.c:347
#12 0x00007fa6a56b7fb9 in g_object_unref () at /lib64/libgobject-2.0.so.0
#13 0x00007fa69f6ba212 in red_channel_client_push (rcc=0x563304df2360) at red-channel-client.c:1341
#14 0x00007fa69f68b259 in red_char_device_send_msg_to_client (client=<optimized out>, msg=0x5633059b6310, dev=0x563304e08bc0) at char-device.c:305
#15 0x00007fa69f68b259 in red_char_device_send_msg_to_clients (msg=0x5633059b6310, dev=0x563304e08bc0) at char-device.c:305
#16 0x00007fa69f68b259 in red_char_device_read_from_device (dev=0x563304e08bc0) at char-device.c:353
#17 0x000056330317d01d in spice_chr_write (chr=0x563304cafe20, buf=0x563304cc50b0 "{\"timestamp\": {\"seconds\": 1532944763, \"microseconds\": 326636}, \"event\": \"SHUTDOWN\", \"data\": {\"guest\": false}}\r\n", len=111) at /home/elmarco/src/qq/chardev/spice.c:199
#18 0x00005633034deee7 in qemu_chr_write_buffer (s=0x563304cafe20, buf=0x563304cc50b0 "{\"timestamp\": {\"seconds\": 1532944763, \"microseconds\": 326636}, \"event\": \"SHUTDOWN\", \"data\": {\"guest\": false}}\r\n", len=111, offset=0x7ffc6ab5ea70, write_all=false) at /home/elmarco/src/qq/chardev/char.c:112
#19 0x00005633034df054 in qemu_chr_write (s=0x563304cafe20, buf=0x563304cc50b0 "{\"timestamp\": {\"seconds\": 1532944763, \"microseconds\": 326636}, \"event\": \"SHUTDOWN\", \"data\": {\"guest\": false}}\r\n", len=111, write_all=false) at /home/elmarco/src/qq/chardev/char.c:147
#20 0x00005633034e1e13 in qemu_chr_fe_write (be=0x563304dbb800, buf=0x563304cc50b0 "{\"timestamp\": {\"seconds\": 1532944763, \"microseconds\": 326636}, \"event\": \"SHUTDOWN\", \"data\": {\"guest\": false}}\r\n", len=111) at /home/elmarco/src/qq/chardev/char-fe.c:42
#21 0x0000563302fa6334 in monitor_flush_locked (mon=0x563304dbb800) at /home/elmarco/src/qq/monitor.c:425
#22 0x0000563302fa6520 in monitor_puts (mon=0x563304dbb800, str=0x563305de7e9e "") at /home/elmarco/src/qq/monitor.c:468
#23 0x0000563302fa680c in qmp_send_response (mon=0x563304dbb800, rsp=0x563304df5730) at /home/elmarco/src/qq/monitor.c:517
#24 0x0000563302fa6905 in qmp_queue_response (mon=0x563304dbb800, rsp=0x563304df5730) at /home/elmarco/src/qq/monitor.c:538
#25 0x0000563302fa6b5b in monitor_qapi_event_emit (event=QAPI_EVENT_SHUTDOWN, qdict=0x563304df5730) at /home/elmarco/src/qq/monitor.c:624
#26 0x0000563302fa6c4b in monitor_qapi_event_queue (event=QAPI_EVENT_SHUTDOWN, qdict=0x563304df5730, errp=0x7ffc6ab5ed00) at /home/elmarco/src/qq/monitor.c:649
#27 0x0000563303548cce in qapi_event_send_shutdown (guest=false, errp=0x563303d8d0f0 <error_abort>) at qapi/qapi-events-run-state.c:58
#28 0x000056330313bcd7 in main_loop_should_exit () at /home/elmarco/src/qq/vl.c:1822
#29 0x000056330313bde3 in main_loop () at /home/elmarco/src/qq/vl.c:1862
#30 0x0000563303143781 in main (argc=3, argv=0x7ffc6ab5f068, envp=0x7ffc6ab5f088) at /home/elmarco/src/qq/vl.c:4644
Note that error report is now moved to the first caller, which may
receive an error for a recursed event. This is probably fine (95% of
callers use &error_abort, the rest have NULL error and ignore it)
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180731150144.14022-1-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[*_no_recurse renamed to *_no_reenter, local variables reordered]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
@cur_mon is null unless the main thread is running monitor code, either
HMP code within monitor_read(), or QMP code within
monitor_qmp_dispatch().
Use of @cur_mon outside the main thread is therefore unsafe.
Most of its uses are in monitor command handlers. These run in the main
thread.
However, there are also uses hiding elsewhere, such as in
error_vprintf(), and thus error_report(), making these functions unsafe
outside the main thread. No such unsafe uses are known at this time.
Regardless, this is an unnecessary trap. It's an ancient trap, though.
More recently, commit cf869d5317 "qmp: support out-of-band (oob)
execution" spiced things up: the monitor I/O thread assigns to @cur_mon
when executing commands out-of-band. Having two threads save, set and
restore @cur_mon without synchronization is definitely unsafe. We can
end up with @cur_mon null while the main thread runs monitor code, or
non-null while it runs non-monitor code.
We could fix this by making the I/O thread not mess with @cur_mon, but
that would leave the trap armed and ready.
Instead, make @cur_mon thread-local. It's now reliably null unless the
thread is running monitor code.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
[peterx: update subject and commit message written by Markus]
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180720033451.32710-1-peterx@redhat.com>
When tracepoint handle_qmp_command is enabled, we crash on JSON syntax
errors. Broken in commit 1cc3747152. Fix by skipping the tracepoint
on JSON syntax error. Before the flawed commit, we skipped it by
returning early.
Fixes: CID 1394216
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180716091012.29510-1-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
qmp_error_response() will free the given error. Fix double-free in
later qmp_request_free().
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180705164201.9853-1-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Fixes: 1cc3747152
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-32-armbru@redhat.com>
qmp_greeting() offers capabilities to the client, and
qmp_qmp_capabilities() accepts or denies capabilities requested by the
client. The two compute the set of available capabilities
independently. Not nice.
Clean this up as follows. Compute available capabilities just once in
monitor_qmp_caps_reset(), and store them in Monitor member
qmp.capab_offered[]. Have qmp_greeting() and qmp_qmp_capabilities()
use that. Both are now oblivious of capability details.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-31-armbru@redhat.com>
monitor_qmp_respond() takes both a response object and an error
object. If an error object is non-null, the response object must be
null, and the response is built from the error object.
Of the two callers, one always passes a null response object, and one
a null error object. Move building the response object from the error
object to the latter, and drop the error object parameter.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-27-armbru@redhat.com>
get_qmp_greeting() returns a QDict * as QObject *. It's caller
converts it right back.
Return QDict * instead. While there, rename to qmp_greeting().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-26-armbru@redhat.com>
monitor_json_emitter() and monitor_json_emitter_raw() are
unnecessarily general: they can send arbitrary JSON values, even
though we only ever use them for QMP, which may send only JSON
objects.
Specialize the argument from QObject * to QDict *, and rename to
qmp_queue_response(), qmp_send_response().
All callers but one lose an upcast. The lone exception gains a
downcast; the next commit will get rid of it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-25-armbru@redhat.com>
By using the more specific type, we get fewer downcasts. The
downcasts are safe, but not obviously so, at least not locally.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-24-armbru@redhat.com>
All callers of qmp_build_error_object() duplicate the code to wrap it
in a response object. Replace it by qmp_error_response() that
captures the duplicated code, including error_free().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-23-armbru@redhat.com>
Wrapping global variables in a struct without a use for the wrapper
struct buys us nothing but longer lines. Unwrap them.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-21-armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-20-armbru@redhat.com>
handle_qmp_command() reports JSON syntax errors right away. This is
wrong when OOB is enabled, because the errors can "jump the queue"
then.
The previous commit fixed the same bug for semantic errors, by
delaying the checking until dispatch. We can't delay the checking, so
delay the reporting.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-19-armbru@redhat.com>
handle_qmp_command() reports certain errors right away. This is wrong
when OOB is enabled, because the errors can "jump the queue" then, as
the previous commit demonstrates.
To fix, we need to delay errors until dispatch. Do that for semantic
errors, mostly by reverting ill-advised parts of commit cf869d5317
"qmp: support out-of-band (oob) execution". Bonus: doesn't run
qmp_dispatch_check_obj() twice, once in handle_qmp_command(), and
again in do_qmp_dispatch(). That's also due to commit cf869d5317.
The next commit will fix queue jumping for syntax errors.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-18-armbru@redhat.com>
When OOB is enabled, out-of-band commands are executed right away,
everything else is queued. This lets out-of-band commands "jump the
queue".
However, certain errors are always reported right away, and therefore
can jump the queue even when the erroneous input does not request
out-of-band execution. These errors are pretty unlikely to occur in
production, but it's wrong all the same. Mark FIXME.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180703085358.13941-17-armbru@redhat.com>
Change monitor_qmp_dispatch_one() to take its parameters unwrapped,
move monitor_resume() to the one caller that needs it, rename the
function to monitor_qmp_dispatch().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-16-armbru@redhat.com>
monitor_qmp_dispatch_one() frees a QMPRequest manually, because it
needs to keep a reference to ->id. Premature optimization. Take an
additional reference so we can use qmp_request_free().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-15-armbru@redhat.com>
Commit 71da4667db "monitor: separate QMP parser and dispatcher" moved
the handle_qmp_command tracepoint from handle_qmp_command() to
monitor_qmp_dispatch_one(). This delays tracing from enqueue time to
dequeue time. Revert that. Dequeue remains adequately visible via
tracepoint monitor_qmp_cmd_in_band.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-14-armbru@redhat.com>
Commit cf869d5317 "qmp: support out-of-band (oob) execution" added a
general mechanism for command-independent arguments just for an
out-of-band flag:
The "control" key is introduced to store this extra flag. "control"
field is used to store arguments that are shared by all the commands,
rather than command specific arguments. Let "run-oob" be the first.
However, it failed to reject unknown members of "control". For
instance, in QMP command
{"execute": "query-name", "id": 42, "control": {"crap": true}}
"crap" gets silently ignored.
Instead of fixing this, revert the general "control" mechanism
(because YAGNI), and do it the way I initially proposed, with key
"exec-oob". Simpler code, simpler interface.
An out-of-band command
{"execute": "migrate-pause", "id": 42, "control": {"run-oob": true}}
becomes
{"exec-oob": "migrate-pause", "id": 42}
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-13-armbru@redhat.com>
[Commit message typo fixed]
Commit cf869d5317 "qmp: support out-of-band (oob) execution"
accidentally made qemu-ga accept and ignore "control". Fix that.
Out-of-band execution in a monitor that doesn't support it now fails
with
{"error": {"class": "GenericError", "desc": "QMP input member 'control' is unexpected"}}
instead of
{"error": {"class": "GenericError", "desc": "Please enable out-of-band first for the session during capabilities negotiation"}}
The old description is suboptimal when out-of-band cannot not be
enabled, or the command doesn't support out-of-band execution.
The new description is a bit unspecific, but it'll do.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-12-armbru@redhat.com>
Commit cf869d5317 "qmp: support out-of-band (oob) execution" changed
how we check "id":
Note that in the patch I exported qmp_dispatch_check_obj() to be
used to check the request earlier, and at the same time allowed
"id" field to be there since actually we always allow that.
The part after "and" is ill-advised: it makes qemu-ga accept and
ignore "id". Revert.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-10-armbru@redhat.com>
Commit cf869d5317 "qmp: support out-of-band (oob) execution" made
"id" mandatory for all commands when the client accepted capability
"oob". This is rather onerous when you play with QMP by hand, and
unnecessarily so: only out-of-band commands need an ID for reliable
matching of response to command.
Revert that part of commit cf869d5317 for now, but have documentation
advise on the need to use "id" with out-of-band commands.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180703085358.13941-8-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Events are broadcast to all monitors. If another monitor's client has
a command with the same ID in flight, the event will incorrectly claim
that command was dropped. This must be fixed before out-of-band
execution can graduate from "experimental".
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-5-armbru@redhat.com>
Add #if defined(CONFIG_SPICE) in generated code, and adjust the
qmp/hmp code accordingly.
query-qmp-schema no longer reports the command/events etc as
available when disabled at compile time.
Commands made conditional:
* query-spice
Before the patch, the command for !CONFIG_SPICE is unregistered. It
will fail with the same error.
Events made conditional:
* SPICE_CONNECTED, SPICE_INITIALIZED, SPICE_DISCONNECTED,
SPICE_MIGRATE_COMPLETED
Add TODO for conditional SPICE chardevs, delayed until the supports
for conditional members lands.
No HMP change, the code was already conditional.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180703155648.11933-15-marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-3-armbru@redhat.com>
Affects documentation and a few error messages.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-2-armbru@redhat.com>
It eases code review, unit is explicit.
Patch generated using:
$ git grep -n '[<>][<>]= ?[1-5]0'
and modified manually.
Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20180625124238.25339-43-f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Previously we clean up the queues when we got CLOSED event. It was used
to make sure we won't send leftover replies/events of a old client to a
new client which makes perfect sense. However this will also drop the
replies/events even if the output port of the previous chardev backend
is still open, which can lead to missing of the last replies/events.
Now this patch does an extra operation to flush the response queue
before cleaning up.
In most cases, a QMP session will be based on a bidirectional channel (a
TCP port, for example, we read/write to the same socket handle), so in
port and out port of the backend chardev are fundamentally the same
port. In these cases, it does not really matter much on whether we'll
flush the response queue since flushing will fail anyway. However there
can be cases where in & out ports of the QMP monitor's backend chardev
are separated. Here is an example:
cat $QMP_COMMANDS | qemu -qmp stdio ... | filter_commands
In this case, the backend is fd-typed, and it is connected to stdio
where in port is stdin and out port is stdout. Now if we drop all the
events on the response queue then filter_command process might miss some
events that it might expect. The thing is that, when stdin closes,
stdout might still be there alive!
In practice, I encountered SHUTDOWN event missing when running test with
iotest 087 with Out-Of-Band enabled. Here is one of the ways that this
can happen (after "quit" command is executed and QEMU quits the main
loop):
1. [main thread] QEMU queues a SHUTDOWN event into response queue.
2. "cat" terminates (to distinguish it from the animal, I quote it).
3. [monitor iothread] QEMU's monitor iothread reads EOF from stdin.
4. [monitor iothread] QEMU's monitor iothread calls the CLOSED event
hook for the monitor, which will destroy the response queue of the
monitor, then the SHUTDOWN event is dropped.
5. [main thread] QEMU's main thread cleans up the monitors in
monitor_cleanup(). When trying to flush pending responses, it sees
nothing. SHUTDOWN is lost forever.
Note that before the monitor iothread was introduced, step [4]/[5] could
never happen since the main loop was the only place to detect the EOF
event of stdin and run the CLOSED event hooks. Now things can happen in
parallel in the iothread.
Without this patch, iotest 087 will have ~10% chance to miss the
SHUTDOWN event and fail when with Out-Of-Band enabled:
--- /home/peterx/git/qemu/tests/qemu-iotests/087.out
+++ /home/peterx/git/qemu/bin/tests/qemu-iotests/087.out.bad
@@ -8,7 +8,6 @@
{"return": {}}
{"error": {"class": "GenericError", "desc": "'node-name' must be
specified for the root node"}}
{"return": {}}
-{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
=== Duplicate ID ===
@@ -53,7 +52,6 @@
{"return": {}}
{"return": {}}
{"return": {}}
-{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
This patch fixes the problem.
Fixes: 6d2d563f8c ("qmp: cleanup qmp queues properly", 2018-03-27)
Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180620073223.31964-4-peterx@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message and a comment touched up]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
