QObject patches for 2018-09-24
-----BEGIN PGP SIGNATURE----- iQIcBAABAgAGBQJbqQxWAAoJEDhwtADrkYZTvMkQAJlraQ5ydNTLEcaQ2GPjzbNF n34hUjT8K0JQmtiLTdiZvcEmqN9VezPJtOgoGyOFljpdJOBgmThXkWp2STyEF4lo sYpA/ml8Mf39TCKjGQGmelxOuSHXmSuEWbCkcZLS/xbf/phMPHulVywcU8UP2ehz F7k5FXSx8MxA7a86lhhegXkK6O0+zvlnvR2tjufJdL0U/V1qXyKqdnOo5ZG7A/H9 +8PvhiVxHr+Id0+1iFqWYzL703zHDWQvfCxzI5arMD9X8jRulBli+eW1LJOTM8SK Pcel9xcSVsp53TIhD0+jG6OS88osMQP/JO3ND8qKFBbJ8f/WXKyskIUFgK9oVxX3 083tcCqCwYFe3THYzY8d5hyhP8OA3ddnSLyA0LV80APi5Z9z+eERSYwCdEad96nS SEl6kLT8VNoVxPi6lPoxsTKJDjCVWesgXkRH0KkzC9JsX0oweW+3z8rNEw9JIeEM VtMnqqG7aFPmlc0kcmNCGSWKNLHymN5ZxylHfQcyauzIPKO4eS3XCwtF4NB5npBJ I1s14NJIHeeSADGaQLTHRLkL1iY3q8ZtAfK+SwnGFtEgIIRHST96KAXDbxyJow8P Ommd2N/J57M68rJUtqBH0bxu58A7AeKN+DrxpeTpgzlDY+/LxLJS46pHVzu+zqim NpXyHG6C+DKcwd/+jFmk =BKOg -----END PGP SIGNATURE----- Merge remote-tracking branch 'remotes/armbru/tags/pull-qobject-2018-09-24' into staging QObject patches for 2018-09-24 # gpg: Signature made Mon 24 Sep 2018 17:09:58 BST # gpg: using RSA key 3870B400EB918653 # gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" # gpg: aka "Markus Armbruster <armbru@pond.sub.org>" # Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867 4E5F 3870 B400 EB91 8653 * remotes/armbru/tags/pull-qobject-2018-09-24: json: Eliminate lexer state IN_WHITESPACE, pseudo-token JSON_SKIP json: Eliminate lexer state IN_ERROR json: Nicer recovery from lexical errors json: Make lexer's "character consumed" logic less confusing json: Clean up how lexer consumes "end of input" json: Fix lexer for lookahead character beyond '\x7F' Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Peter Maydell
commit
f69d20fa8b
@ -100,7 +100,7 @@
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*/
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enum json_lexer_state {
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IN_ERROR = 0, /* must really be 0, see json_lexer[] */
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IN_RECOVERY = 1,
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IN_DQ_STRING_ESCAPE,
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IN_DQ_STRING,
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IN_SQ_STRING_ESCAPE,
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@ -115,25 +115,44 @@ enum json_lexer_state {
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IN_SIGN,
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IN_KEYWORD,
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IN_INTERP,
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IN_WHITESPACE,
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IN_START,
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IN_START_INTERP, /* must be IN_START + 1 */
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};
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QEMU_BUILD_BUG_ON(JSON_ERROR != 0);
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QEMU_BUILD_BUG_ON(IN_RECOVERY != JSON_ERROR + 1);
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QEMU_BUILD_BUG_ON((int)JSON_MIN <= (int)IN_START_INTERP);
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QEMU_BUILD_BUG_ON(JSON_MAX >= 0x80);
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QEMU_BUILD_BUG_ON(IN_START_INTERP != IN_START + 1);
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#define TERMINAL(state) [0 ... 0x7F] = (state)
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/* Return whether TERMINAL is a terminal state and the transition to it
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from OLD_STATE required lookahead. This happens whenever the table
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below uses the TERMINAL macro. */
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#define TERMINAL_NEEDED_LOOKAHEAD(old_state, terminal) \
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(terminal != IN_ERROR && json_lexer[(old_state)][0] == (terminal))
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#define LOOKAHEAD 0x80
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#define TERMINAL(state) [0 ... 0xFF] = ((state) | LOOKAHEAD)
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static const uint8_t json_lexer[][256] = {
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/* Relies on default initialization to IN_ERROR! */
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/* error recovery */
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[IN_RECOVERY] = {
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/*
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* Skip characters until a structural character, an ASCII
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* control character other than '\t', or impossible UTF-8
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* bytes '\xFE', '\xFF'. Structural characters and line
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* endings are promising resynchronization points. Clients
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* may use the others to force the JSON parser into known-good
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* state; see docs/interop/qmp-spec.txt.
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*/
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[0 ... 0x1F] = IN_START | LOOKAHEAD,
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[0x20 ... 0xFD] = IN_RECOVERY,
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[0xFE ... 0xFF] = IN_START | LOOKAHEAD,
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['\t'] = IN_RECOVERY,
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['['] = IN_START | LOOKAHEAD,
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[']'] = IN_START | LOOKAHEAD,
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['{'] = IN_START | LOOKAHEAD,
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['}'] = IN_START | LOOKAHEAD,
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[':'] = IN_START | LOOKAHEAD,
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[','] = IN_START | LOOKAHEAD,
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},
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/* double quote string */
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[IN_DQ_STRING_ESCAPE] = {
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[0x20 ... 0xFD] = IN_DQ_STRING,
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@ -157,7 +176,7 @@ static const uint8_t json_lexer[][256] = {
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/* Zero */
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[IN_ZERO] = {
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TERMINAL(JSON_INTEGER),
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['0' ... '9'] = IN_ERROR,
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['0' ... '9'] = JSON_ERROR,
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['.'] = IN_MANTISSA,
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},
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@ -208,15 +227,6 @@ static const uint8_t json_lexer[][256] = {
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['a' ... 'z'] = IN_KEYWORD,
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},
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/* whitespace */
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[IN_WHITESPACE] = {
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TERMINAL(JSON_SKIP),
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[' '] = IN_WHITESPACE,
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['\t'] = IN_WHITESPACE,
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['\r'] = IN_WHITESPACE,
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['\n'] = IN_WHITESPACE,
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},
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/* interpolation */
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[IN_INTERP] = {
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TERMINAL(JSON_INTERP),
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@ -243,14 +253,25 @@ static const uint8_t json_lexer[][256] = {
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[','] = JSON_COMMA,
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[':'] = JSON_COLON,
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['a' ... 'z'] = IN_KEYWORD,
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[' '] = IN_WHITESPACE,
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['\t'] = IN_WHITESPACE,
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['\r'] = IN_WHITESPACE,
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['\n'] = IN_WHITESPACE,
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[' '] = IN_START,
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['\t'] = IN_START,
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['\r'] = IN_START,
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['\n'] = IN_START,
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},
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[IN_START_INTERP]['%'] = IN_INTERP,
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};
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static inline uint8_t next_state(JSONLexer *lexer, char ch, bool flush,
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bool *char_consumed)
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{
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uint8_t next;
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assert(lexer->state <= ARRAY_SIZE(json_lexer));
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next = json_lexer[lexer->state][(uint8_t)ch];
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*char_consumed = !flush && !(next & LOOKAHEAD);
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return next & ~LOOKAHEAD;
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}
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void json_lexer_init(JSONLexer *lexer, bool enable_interpolation)
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{
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lexer->start_state = lexer->state = enable_interpolation
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@ -261,7 +282,8 @@ void json_lexer_init(JSONLexer *lexer, bool enable_interpolation)
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static void json_lexer_feed_char(JSONLexer *lexer, char ch, bool flush)
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{
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int char_consumed, new_state;
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int new_state;
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bool char_consumed = false;
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lexer->x++;
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if (ch == '\n') {
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@ -269,11 +291,10 @@ static void json_lexer_feed_char(JSONLexer *lexer, char ch, bool flush)
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lexer->y++;
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}
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do {
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assert(lexer->state <= ARRAY_SIZE(json_lexer));
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new_state = json_lexer[lexer->state][(uint8_t)ch];
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char_consumed = !TERMINAL_NEEDED_LOOKAHEAD(lexer->state, new_state);
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if (char_consumed && !flush) {
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while (flush ? lexer->state != lexer->start_state : !char_consumed) {
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new_state = next_state(lexer, ch, flush, &char_consumed);
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if (char_consumed) {
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assert(!flush);
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g_string_append_c(lexer->token, ch);
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}
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@ -292,33 +313,23 @@ static void json_lexer_feed_char(JSONLexer *lexer, char ch, bool flush)
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json_message_process_token(lexer, lexer->token, new_state,
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lexer->x, lexer->y);
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/* fall through */
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case JSON_SKIP:
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case IN_START:
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g_string_truncate(lexer->token, 0);
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new_state = lexer->start_state;
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break;
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case IN_ERROR:
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/* XXX: To avoid having previous bad input leaving the parser in an
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* unresponsive state where we consume unpredictable amounts of
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* subsequent "good" input, percolate this error state up to the
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* parser by emitting a JSON_ERROR token, then reset lexer state.
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*
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* Also note that this handling is required for reliable channel
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* negotiation between QMP and the guest agent, since chr(0xFF)
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* is placed at the beginning of certain events to ensure proper
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* delivery when the channel is in an unknown state. chr(0xFF) is
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* never a valid ASCII/UTF-8 sequence, so this should reliably
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* induce an error/flush state.
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*/
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case JSON_ERROR:
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json_message_process_token(lexer, lexer->token, JSON_ERROR,
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lexer->x, lexer->y);
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new_state = IN_RECOVERY;
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/* fall through */
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case IN_RECOVERY:
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g_string_truncate(lexer->token, 0);
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lexer->state = lexer->start_state;
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return;
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break;
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default:
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break;
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}
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lexer->state = new_state;
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} while (!char_consumed && !flush);
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}
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/* Do not let a single token grow to an arbitrarily large size,
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* this is a security consideration.
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@ -342,9 +353,8 @@ void json_lexer_feed(JSONLexer *lexer, const char *buffer, size_t size)
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void json_lexer_flush(JSONLexer *lexer)
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{
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if (lexer->state != lexer->start_state) {
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json_lexer_feed_char(lexer, 0, true);
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}
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json_lexer_feed_char(lexer, 0, true);
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assert(lexer->state == lexer->start_state);
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json_message_process_token(lexer, lexer->token, JSON_END_OF_INPUT,
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lexer->x, lexer->y);
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}
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@ -16,10 +16,11 @@
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#include "qapi/qmp/json-parser.h"
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typedef enum json_token_type {
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JSON_MIN = 100,
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JSON_LCURLY = JSON_MIN,
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JSON_ERROR = 0, /* must be zero, see json_lexer[] */
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/* Gap for lexer states */
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JSON_LCURLY = 100,
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JSON_MIN = JSON_LCURLY,
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JSON_RCURLY,
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JSON_LSQUARE,
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JSON_RSQUARE,
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@ -30,9 +31,8 @@ typedef enum json_token_type {
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JSON_KEYWORD,
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JSON_STRING,
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JSON_INTERP,
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JSON_SKIP,
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JSON_ERROR,
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JSON_END_OF_INPUT,
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JSON_MAX = JSON_END_OF_INPUT
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} JSONTokenType;
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typedef struct JSONToken JSONToken;
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@ -76,10 +76,7 @@ static void test_malformed(QTestState *qts)
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assert_recovered(qts);
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/* lexical error: interpolation */
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qtest_qmp_send_raw(qts, "%%p\n");
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/* two errors, one for "%", one for "p" */
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resp = qtest_qmp_receive(qts);
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qmp_assert_error_class(resp, "GenericError");
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qtest_qmp_send_raw(qts, "%%p");
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resp = qtest_qmp_receive(qts);
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qmp_assert_error_class(resp, "GenericError");
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assert_recovered(qts);
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