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2023-05-22docs/interop: Convert qmp-spec.txt to rSTPeter Maydell1-1/+1
Convert the qmp-spec.txt document to restructuredText. Notable points about the conversion: * numbers at the start of section headings are removed, to match the style of the rest of the manual * cross-references to other sections or documents are hyperlinked * various formatting tweaks (notably the examples, which need the -> and <- prefixed so the QMP code-block lexer will accept them) * English prose fixed in a few places Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-Id: <20230515162245.3964307-2-peter.maydell@linaro.org> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> [.. code-block:: dumbed down to :: to work around CI failure]
2019-03-26json: Fix off-by-one assert check in next_state()Liam Merwick1-1/+1
The assert checking if the value of lexer->state in next_state(), which is used as an index to the 'json_lexer' array, incorrectly checks for an index value less than or equal to ARRAY_SIZE(json_lexer). Fix assert so that it just checks for an index less than the array size. Signed-off-by: Liam Merwick <liam.merwick@oracle.com> Message-Id: <1553169472-25325-1-git-send-email-liam.merwick@oracle.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Li Qiang <liq3ea@gmail.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2018-09-24json: Eliminate lexer state IN_WHITESPACE, pseudo-token JSON_SKIPMarkus Armbruster1-17/+5
The lexer ignores whitespace like this: on whitespace on non-ws spontaneously IN_START --> IN_WHITESPACE --> JSON_SKIP --> IN_START ^ | \__/ on whitespace This accumulates a whitespace token in state IN_WHITESPACE, only to throw it away on the transition via JSON_SKIP to the start state. Wasteful. Go from IN_START to IN_START on whitespace directly, dropping the whitespace character. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180831075841.13363-7-armbru@redhat.com>
2018-09-24json: Eliminate lexer state IN_ERRORMarkus Armbruster1-4/+5
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180831075841.13363-6-armbru@redhat.com>
2018-09-24json: Nicer recovery from lexical errorsMarkus Armbruster1-14/+29
When the lexer chokes on an input character, it consumes the character, emits a JSON error token, and enters its start state. This can lead to suboptimal error recovery. For instance, input 0123 , produces the tokens JSON_ERROR 01 JSON_INTEGER 23 JSON_COMMA , Make the lexer skip characters after a lexical error until a structural character ('[', ']', '{', '}', ':', ','), an ASCII control character, or '\xFE', or '\xFF'. Note that we must not skip ASCII control characters, '\xFE', '\xFF', because those are documented to force the JSON parser into known-good state, by docs/interop/qmp-spec.txt. The lexer now produces JSON_ERROR 01 JSON_COMMA , Update qmp-test for the nicer error recovery: QMP now reports just one error for input %p instead of two. Also drop the newline after %p; it was needed to tease out the second error. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180831075841.13363-5-armbru@redhat.com> [Conflict with commit ebb4d82d888 resolved]
2018-09-24json: Make lexer's "character consumed" logic less confusingMarkus Armbruster1-11/+16
The lexer uses macro TERMINAL_NEEDED_LOOKAHEAD() to decide whether a state transition consumes the input character. It returns true when the state transition is defined with the TERMINAL() macro. To detect that, it checks whether input '\0' would have resulted in the same state transition, and the new state is not IN_ERROR. Why does that even work? For all states, the new state on input '\0' is either IN_ERROR or defined with TERMINAL(). If the state transition equals the one we'd get for input '\0', it goes to IN_ERROR or to the argument of TERMINAL(). We never use TERMINAL(IN_ERROR), because it makes no sense. Thus, if it doesn't go to IN_ERROR, it must be defined with TERMINAL(). Since this isn't quite confusing enough, we negate the result to get @char_consumed, and ignore it when @flush is true. Instead of deriving the lookahead bit from the state transition, make it explicit. This is easier to understand, and a bit more flexible, too. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180831075841.13363-4-armbru@redhat.com>
2018-09-24json: Clean up how lexer consumes "end of input"Markus Armbruster1-8/+9
When the lexer isn't in its start state at the end of input, it's working on a token. To flush it out, it needs to transit to its start state on "end of input" lookahead. There are two ways to the start state, depending on the current state: * If the lexer is in a TERMINAL(JSON_FOO) state, it can emit a JSON_FOO token. * Else, it can go to IN_ERROR state, and emit a JSON_ERROR token. There are complications, however: * The transition to IN_ERROR state consumes the input character and adds it to the JSON_ERROR token. The latter is inappropriate for the "end of input" character, so we suppress that. See also recent commit a2ec6be72b8 "json: Fix lexer to include the bad character in JSON_ERROR token". * The transition to a TERMINAL(JSON_FOO) state doesn't consume the input character. In that case, the lexer normally loops until it is consumed. We have to suppress that for the "end of input" input character. If we didn't, the lexer would consume it by entering IN_ERROR state, emitting a bogus JSON_ERROR token. We fixed that in commit bd3924a33a6. However, simply breaking the loop this way assumes that the lexer needs exactly one state transition to reach its start state. That assumption is correct now, but it's unclean, and I'll soon break it. Clean up: instead of breaking the loop after one iteration, break it after it reached the start state. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180831075841.13363-3-armbru@redhat.com>
2018-09-24json: Fix lexer for lookahead character beyond '\x7F'Markus Armbruster1-1/+1
The lexer fails to end a valid token when the lookahead character is beyond '\x7F'. For instance, input true\xC2\xA2 produces the tokens JSON_ERROR true\xC2 JSON_ERROR \xA2 This should be JSON_KEYWORD true JSON_ERROR \xC2 JSON_ERROR \xA2 instead. The culprit is #define TERMINAL(state) [0 ... 0x7F] = (state) It leaves [0x80..0xFF] zero, i.e. IN_ERROR. Has always been broken. Fix it to initialize the complete array. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180831075841.13363-2-armbru@redhat.com>
2018-08-24json: Clean up headersMarkus Armbruster1-2/+1
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>
2018-08-24qobject: Drop superfluous includes of qemu-common.hMarkus Armbruster1-1/+0
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-53-armbru@redhat.com>
2018-08-24json: Fix streamer not to ignore trailing unterminated structuresMarkus Armbruster1-0/+2
json_message_process_token() 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 json_parser_parse(). If a non-empty sequence of tokens remains at the end of the parse, it's silently ignored. check-qjson.c cases unterminated_array(), unterminated_array_comma(), unterminated_dict(), unterminated_dict_comma() demonstrate this bug. Fix as follows. Introduce a JSON_END_OF_INPUT token. When the streamer receives it, it feeds the accumulated tokens to json_parser_parse(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-46-armbru@redhat.com>
2018-08-24json: Improve names of lexer states related to numbersMarkus Armbruster1-17/+17
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-43-armbru@redhat.com>
2018-08-24json: Leave rejecting invalid interpolation to parserMarkus Armbruster1-38/+6
Both lexer and parser reject invalid interpolation specifications. The parser's check is useless. The lexer ends the token right after the first bad character. This tends to lead to suboptimal error reporting. For instance, input [ %04d ] produces the tokens JSON_LSQUARE [ JSON_ERROR %0 JSON_INTEGER 4 JSON_KEYWORD d JSON_RSQUARE ] The parser then yields an error, an object and two more errors: error: Invalid JSON syntax object: 4 error: JSON parse error, invalid keyword error: JSON parse error, expecting value Dumb down the lexer to accept [A-Za-z0-9]*. The parser's check is now used. Emit a proper error there. The lexer now produces JSON_LSQUARE [ JSON_INTERP %04d JSON_RSQUARE ] and the parser reports just JSON parse error, invalid interpolation '%04d' Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-41-armbru@redhat.com>
2018-08-24json: Pass lexical errors and limit violations to callbackMarkus Armbruster1-2/+1
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>
2018-08-24json: Treat unwanted interpolation as lexical errorMarkus Armbruster1-12/+18
The JSON parser optionally supports interpolation. The lexer recognizes interpolation tokens unconditionally. The parser rejects them when interpolation is disabled, in parse_interpolation(). However, it neglects to set an error then, which can make json_parser_parse() fail without setting an error. Move the check for unwanted interpolation from the parser's parse_interpolation() into the lexer's finite state machine. When interpolation is disabled, '%' is now handled like any other unexpected character. The next commit will improve how such lexical errors are handled. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-39-armbru@redhat.com>
2018-08-24json: Rename token JSON_ESCAPE & friends to JSON_INTERPMarkus Armbruster1-32/+32
The JSON parser optionally supports interpolation. The code calls it "escape". Awkward, because it uses the same term for escape sequences within strings. The latter usage is consistent with RFC 8259 "The JavaScript Object Notation (JSON) Data Interchange Format" and ISO C. Call the former "interpolation" instead. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-38-armbru@redhat.com>
2018-08-24json: Have lexer call streamer directlyMarkus Armbruster1-5/+8
json_lexer_init() takes the function to process a token as an argument. It's always json_message_process_token(). Makes the code harder to understand for no actual gain. Drop the indirection. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-34-armbru@redhat.com>
2018-08-24json: remove useless return value from lexer/parserMarc-André Lureau1-15/+8
The lexer always returns 0 when char feeding. Furthermore, none of the caller care about the return value. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20180326150916.9602-10-marcandre.lureau@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20180823164025.12553-32-armbru@redhat.com>
2018-08-24json: Leave rejecting invalid escape sequences to parserMarkus Armbruster1-68/+4
Both lexer and parser reject invalid escape sequences in strings. The parser's check is useless. The lexer ends the token right after the first non-well-formed byte. This tends to lead to suboptimal error reporting. For instance, input {"abc\@ijk": 1} produces the tokens JSON_LCURLY { JSON_ERROR "abc\@ JSON_KEYWORD ijk JSON_ERROR ": 1}\n The parser then reports three errors Invalid JSON syntax JSON parse error, invalid keyword 'ijk' Invalid JSON syntax before it recovers at the newline. Drop the lexer's escape sequence checking, and make it accept the same characters after backslash it accepts elsewhere in strings. It now produces JSON_LCURLY { JSON_STRING "abc\@ijk" JSON_COLON : JSON_INTEGER 1 JSON_RCURLY and the parser reports just JSON parse error, invalid escape sequence in string While there, fix parse_string()'s inaccurate function comment. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-27-armbru@redhat.com>
2018-08-24json: Accept overlong \xC0\x80 as U+0000 ("modified UTF-8")Markus Armbruster1-1/+1
Since the JSON grammer doesn't accept U+0000 anywhere, this merely exchanges one kind of parse error for another. It's purely for consistency with qobject_to_json(), which accepts \xC0\x80 (see commit e2ec3f97680). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-26-armbru@redhat.com>
2018-08-24json: Leave rejecting invalid UTF-8 to parserMarkus Armbruster1-4/+2
Both the lexer and the parser (attempt to) validate UTF-8 in JSON strings. The lexer rejects bytes that can't occur in valid UTF-8: \xC0..\xC1, \xF5..\xFF. This rejects some, but not all invalid UTF-8. It also rejects ASCII control characters \x00..\x1F, in accordance with RFC 8259 (see recent commit "json: Reject unescaped control characters"). When the lexer rejects, it ends the token right after the first bad byte. Good when the bad byte is a newline. Not so good when it's something like an overlong sequence in the middle of a string. For instance, input {"abc\xC0\xAFijk": 1}\n produces the tokens JSON_LCURLY { JSON_ERROR "abc\xC0 JSON_ERROR \xAF JSON_KEYWORD ijk JSON_ERROR ": 1}\n The parser then reports four errors Invalid JSON syntax Invalid JSON syntax JSON parse error, invalid keyword 'ijk' Invalid JSON syntax before it recovers at the newline. The commit before previous made the parser reject invalid UTF-8 sequences. Since then, anything the lexer rejects, the parser would reject as well. Thus, the lexer's rejecting is unnecessary for correctness, and harmful for error reporting. However, we want to keep rejecting ASCII control characters in the lexer, because that produces the behavior we want for unclosed strings. We also need to keep rejecting \xFF in the lexer, because we documented that as a way to reset the JSON parser (docs/interop/qmp-spec.txt section 2.6 QGA Synchronization), which means we can't change how we recover from this error now. I wish we hadn't done that. I think we should treat \xFE the same as \xFF. Change the lexer to accept \xC0..\xC1 and \xF5..\xFD. It now rejects only \x00..\x1F and \xFE..\xFF. Error reporting for invalid UTF-8 in strings is much improved, except for \xFE and \xFF. For the example above, the lexer now produces JSON_LCURLY { JSON_STRING "abc\xC0\xAFijk" JSON_COLON : JSON_INTEGER 1 JSON_RCURLY and the parser reports just JSON parse error, invalid UTF-8 sequence in string Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-25-armbru@redhat.com>
2018-08-24json: Revamp lexer documentationMarkus Armbruster1-9/+71
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-20-armbru@redhat.com>
2018-08-24json: Reject unescaped control charactersMarkus Armbruster1-2/+2
Fix the lexer to reject unescaped control characters in JSON strings, in accordance with RFC 8259 "The JavaScript Object Notation (JSON) Data Interchange Format". Bonus: we now recover more nicely from unclosed strings. E.g. {"one: 1}\n{"two": 2} now recovers cleanly after the newline, where before the lexer remained confused until the next unpaired double quote or lexical error. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-19-armbru@redhat.com>
2018-08-24json: Fix lexer to include the bad character in JSON_ERROR tokenMarkus Armbruster1-2/+2
json_lexer[] maps (lexer state, input character) to the new lexer state. The input character is consumed unless the new state is terminal and the input character doesn't belong to this token, i.e. the state transition uses look-ahead. When this is the case, input character '\0' would result in the same state transition. TERMINAL_NEEDED_LOOKAHEAD() exploits this. Except this is wrong for transitions to IN_ERROR. There, the offending input character is in fact consumed: case IN_ERROR returns. It isn't added to the JSON_ERROR token, though. Fix that by making TERMINAL_NEEDED_LOOKAHEAD() return false for transitions to IN_ERROR. There's a slight complication. json_lexer_flush() passes input character '\0' to flush an incomplete token. If this results in JSON_ERROR, we'd now add the '\0' to the token. Suppress that. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-18-armbru@redhat.com>
2017-06-20json: learn to parse uint64 numbersMarc-André Lureau1-0/+4
Switch strtoll() usage to qemu_strtoi64() helper while at it. Add a few tests for large numbers. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20170607163635.17635-11-marcandre.lureau@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-06-30qobject: Correct JSON lexer grammar commentsEric Blake1-5/+14
Fix the regex comments describing what we parse as JSON. No change to the lexer itself, just to the comments: - The "" and '' string construction was missing alternation between different escape sequences - The construction for numbers forgot to handle optional leading '-' - The construction for numbers was grouped incorrectly so that it didn't permit '0.1' - The construction for numbers forgot to mark the exponent as optional - No mention that our '' string and "\'" are JSON extensions - No mention of our %d and related extensions when constructing JSON Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465526889-8339-2-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Eric's regexp simplification squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-04qobject: Clean up includesPeter Maydell1-1/+1
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> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 1454089805-5470-12-git-send-email-peter.maydell@linaro.org
2015-11-26qjson: replace QString in JSONLexer with GStringPaolo Bonzini1-14/+8
JSONLexer only needs a simple resizable buffer. json-streamer.c can allocate memory for each token instead of relying on reference counting of QStrings. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <1448300659-23559-2-git-send-email-pbonzini@redhat.com> [Straightforwardly rebased on my patches, checkpatch made happy] Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-11-26qjson: Give each of the six structural chars its own token typeMarkus Armbruster1-7/+12
Simplifies things, because we always check for a specific one. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1448486613-17634-6-git-send-email-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-11-26qjson: Spell out some silent assumptionsMarkus Armbruster1-1/+6
Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1448486613-17634-5-git-send-email-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-23json-lexer: fix escaped backslash in single-quoted stringPaolo Bonzini1-2/+2
This made the lexer wait for a closing *double* quote. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Amos Kong <akong@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2013-01-12build: move qobject files to qobject/ and libqemuutil.aPaolo Bonzini1-0/+373
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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