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[Qemu-devel] [PULL 17/58] json: Fix lexer to include the bad character i
From: |
Markus Armbruster |
Subject: |
[Qemu-devel] [PULL 17/58] json: Fix lexer to include the bad character in JSON_ERROR token |
Date: |
Fri, 24 Aug 2018 21:31:25 +0200 |
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 <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Message-Id: <address@hidden>
---
qobject/json-lexer.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/qobject/json-lexer.c b/qobject/json-lexer.c
index 980ba159d6..7c0875d225 100644
--- a/qobject/json-lexer.c
+++ b/qobject/json-lexer.c
@@ -76,7 +76,7 @@ QEMU_BUILD_BUG_ON((int)JSON_MIN <= (int)IN_START);
from OLD_STATE required lookahead. This happens whenever the table
below uses the TERMINAL macro. */
#define TERMINAL_NEEDED_LOOKAHEAD(old_state, terminal) \
- (json_lexer[(old_state)][0] == (terminal))
+ (terminal != IN_ERROR && json_lexer[(old_state)][0] == (terminal))
static const uint8_t json_lexer[][256] = {
/* Relies on default initialization to IN_ERROR! */
@@ -304,7 +304,7 @@ static int json_lexer_feed_char(JSONLexer *lexer, char ch,
bool flush)
assert(lexer->state <= ARRAY_SIZE(json_lexer));
new_state = json_lexer[lexer->state][(uint8_t)ch];
char_consumed = !TERMINAL_NEEDED_LOOKAHEAD(lexer->state, new_state);
- if (char_consumed) {
+ if (char_consumed && !flush) {
g_string_append_c(lexer->token, ch);
}
--
2.17.1
- [Qemu-devel] [PULL 00/58] QObject patches for 2018-08-24, Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 07/58] test-qga: Clean up how we test QGA synchronization, Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 04/58] check-qjson: Cover whitespace more thoroughly, Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 03/58] check-qjson: Cover blank and lexically erroneous input, Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 17/58] json: Fix lexer to include the bad character in JSON_ERROR token,
Markus Armbruster <=
- [Qemu-devel] [PULL 06/58] qmp-test: Cover syntax and lexical errors, Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 13/58] check-qjson: Simplify utf8_string(), Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 02/58] check-qjson: Cover multiple JSON objects in same string, Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 20/58] json: Tighten and simplify qstring_from_escaped_str()'s loop, Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 11/58] check-qjson: Consolidate partly redundant string tests, Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 33/58] json: Have lexer call streamer directly, Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 12/58] check-qjson: Cover UTF-8 in single quoted strings, Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 25/58] json: Accept overlong \xC0\x80 as U+0000 ("modified UTF-8"), Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 01/58] docs/interop/qmp-spec: How to force known good parser state, Markus Armbruster, 2018/08/24
- [Qemu-devel] [PULL 15/58] check-qjson qmp-test: Cover control characters more thoroughly, Markus Armbruster, 2018/08/24