json: fully parse input string

I was adding a JSON test, and was shocked to find out our parser
treated the input string of "1" as invalid JSON.  It turns out
that YAJL specifically documents that it buffers input, and that
if the last input read could be a prefix to a longer token, then
you have to explicitly tell the parser that the buffer has ended
before that token will be processed.

It doesn't help that yajl 2 renamed the function from what it was
in yajl 1.

* src/util/virjson.c (virJSONValueFromString): Complete parse, in
case buffer ends in possible token prefix.
* tests/jsontest.c (mymain): Expose the problem.
Signed-off-by: NEric Blake <eblake@redhat.com>

src/util/virjson.c

@@ -38,6 +38,7 @@
 #  define yajl_size_t size_t
 # else
 #  define yajl_size_t unsigned int
+#  define yajl_complete_parse yajl_parse_complete
 # endif
 
 #endif
@@ -1610,7 +1611,8 @@ virJSONValueFromString(const char *jsonstring)
 
     if (yajl_parse(hand,
                    (const unsigned char *)jsonstring,
-                   strlen(jsonstring)) != yajl_status_ok) {
+                   strlen(jsonstring)) != yajl_status_ok ||
+        yajl_complete_parse(hand) != yajl_status_ok) {
         unsigned char *errstr = yajl_get_error(hand, 1,
                                                (const unsigned char*)jsonstring,
                                                strlen(jsonstring));

tests/jsontest.c

@@ -304,6 +304,12 @@ mymain(void)
     DO_TEST_PARSE("string", "[ \"The meaning of life\" ]");
     DO_TEST_PARSE_FAIL("unterminated string", "[ \"The meaning of lif ]");
 
+    DO_TEST_PARSE("integer", "1");
+    DO_TEST_PARSE("boolean", "true");
+    DO_TEST_PARSE("null", "null");
+    DO_TEST_PARSE_FAIL("incomplete keyword", "tr");
+    DO_TEST_PARSE_FAIL("overdone keyword", "truest");
+    DO_TEST_PARSE_FAIL("unknown keyword", "huh");
 
     DO_TEST_PARSE_FAIL("object with numeric keys", "{ 1:1, 2:1, 3:2 }");
     DO_TEST_PARSE_FAIL("unterminated object", "{ \"1\":1, \"2\":1, \"3\":2");