Commit 21813684 authored by James Clark's avatar James Clark Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Make the JSON parser more conformant when in strict mode 

Return an error when a trailing comma is found or a new item is
encountered before a comma or an opening brace. This ensures that the
perf JSON files conform more closely to the spec at https://www.json.org



Reviewed-by: default avatarAndi Kleen <ak@linux.intel.com>
Reviewed-by: default avatarKajol <Jain&lt;kjain@linux.ibm.com>
Signed-off-by: default avatarJames Clark <james.clark@arm.com>
Acked-by: default avatarJiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew.Kilroy@arm.com
Cc: John Garry <john.garry@huawei.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nick.Forrington@arm.com
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20211007110543.564963-3-james.clark@arm.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 08f3e087

tools/perf/pmu-events/jsmn.c

+40 −2
Original line number Diff line number Diff line
@@ -176,6 +176,14 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, 
	jsmnerr_t r;

	int i;

	jsmntok_t *token;

#ifdef JSMN_STRICT

	/*

	 * Keeps track of whether a new object/list/primitive is expected. New items are only

	 * allowed after an opening brace, comma or colon. A closing brace after a comma is not

	 * valid JSON.

	 */

	int expecting_item = 1;

#endif



	for (; parser->pos < len; parser->pos++) {

		char c;
@@ -185,6 +193,10 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, 
		switch (c) {

		case '{':

		case '[':

#ifdef JSMN_STRICT

			if (!expecting_item)

				return JSMN_ERROR_INVAL;

#endif

			token = jsmn_alloc_token(parser, tokens, num_tokens);

			if (token == NULL)

				return JSMN_ERROR_NOMEM;
@@ -196,6 +208,10 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, 
			break;

		case '}':

		case ']':

#ifdef JSMN_STRICT

			if (expecting_item)

				return JSMN_ERROR_INVAL;

#endif

			type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY);

			for (i = parser->toknext - 1; i >= 0; i--) {

				token = &tokens[i];
@@ -219,6 +235,11 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, 
			}

			break;

		case '\"':

#ifdef JSMN_STRICT

			if (!expecting_item)

				return JSMN_ERROR_INVAL;

			expecting_item = 0;

#endif

			r = jsmn_parse_string(parser, js, len, tokens,

					      num_tokens);

			if (r < 0)
@@ -229,11 +250,15 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, 
		case '\t':

		case '\r':

		case '\n':

		case ':':

		case ',':

		case ' ':

			break;

#ifdef JSMN_STRICT

		case ':':

		case ',':

			if (expecting_item)

				return JSMN_ERROR_INVAL;

			expecting_item = 1;

			break;

			/*

			 * In strict mode primitives are:

			 * numbers and booleans.
@@ -253,6 +278,9 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, 
		case 'f':

		case 'n':

#else

		case ':':

		case ',':

			break;

			/*

			 * In non-strict mode every unquoted value

			 * is a primitive.
@@ -260,6 +288,12 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, 
			/*FALL THROUGH */

		default:

#endif



#ifdef JSMN_STRICT

			if (!expecting_item)

				return JSMN_ERROR_INVAL;

			expecting_item = 0;

#endif

			r = jsmn_parse_primitive(parser, js, len, tokens,

						 num_tokens);

			if (r < 0)
@@ -282,7 +316,11 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len, 
			return JSMN_ERROR_PART;

	}



#ifdef JSMN_STRICT

	return expecting_item ? JSMN_ERROR_INVAL : JSMN_SUCCESS;

#else

	return JSMN_SUCCESS;

#endif

}



/*