qjson: Fix qobject_from_json() & friends for multiple values

[qemu.git] / qobject / qjson.c

diff --git a/qobject/qjson.c b/qobject/qjson.c
index 9816a65c7d82e8763456c51f0b5ff692c0f3659b..7f6903648723a1aa9528190f3af980f5134a6fc1 100644 (file)
--- a/qobject/qjson.c
+++ b/qobject/qjson.c
@@ -13,8 +13,6 @@
 
 #include "qemu/osdep.h"
 #include "qapi/error.h"
-#include "qapi/qmp/json-lexer.h"
-#include "qapi/qmp/json-parser.h"
 #include "qapi/qmp/json-streamer.h"
 #include "qapi/qmp/qjson.h"
 #include "qapi/qmp/qbool.h"
@@ -27,25 +25,47 @@
 typedef struct JSONParsingState
 {
     JSONMessageParser parser;
-    va_list *ap;
     QObject *result;
     Error *err;
 } JSONParsingState;
 
-static void parse_json(JSONMessageParser *parser, GQueue *tokens)
+static void consume_json(void *opaque, QObject *json, Error *err)
 {
-    JSONParsingState *s = container_of(parser, JSONParsingState, parser);
+    JSONParsingState *s = opaque;
 
-    s->result = json_parser_parse_err(tokens, s->ap, &s->err);
+    assert(!json != !err);
+    assert(!s->result || !s->err);
+
+    if (s->result) {
+        qobject_unref(s->result);
+        s->result = NULL;
+        error_setg(&s->err, "Expecting at most one JSON value");
+    }
+    if (s->err) {
+        qobject_unref(json);
+        error_free(err);
+        return;
+    }
+    s->result = json;
+    s->err = err;
 }
 
-QObject *qobject_from_jsonv(const char *string, va_list *ap, Error **errp)
+/*
+ * Parse @string as JSON value.
+ * If @ap is non-null, interpolate %-escapes.
+ * Takes ownership of %p arguments.
+ * On success, return the JSON value.
+ * On failure, store an error through @errp and return NULL.
+ * Ownership of %p arguments becomes indeterminate then.  To avoid
+ * leaks, callers passing %p must terminate on error, e.g. by passing
+ * &error_abort.
+ */
+static QObject *qobject_from_jsonv(const char *string, va_list *ap,
+                                   Error **errp)
 {
     JSONParsingState state = {};
 
-    state.ap = ap;
-
-    json_message_parser_init(&state.parser, parse_json);
+    json_message_parser_init(&state.parser, consume_json, &state, ap);
     json_message_parser_feed(&state.parser, string, strlen(string));
     json_message_parser_flush(&state.parser);
     json_message_parser_destroy(&state.parser);
@@ -60,22 +80,71 @@ QObject *qobject_from_json(const char *string, Error **errp)
 }
 
 /*
- * IMPORTANT: This function aborts on error, thus it must not
- * be used with untrusted arguments.
+ * Parse @string as JSON value with %-escapes interpolated.
+ * Abort on error.  Do not use with untrusted @string.
+ * Return the resulting QObject.  It is never null.
+ */
+QObject *qobject_from_vjsonf_nofail(const char *string, va_list ap)
+{
+    va_list ap_copy;
+    QObject *obj;
+
+    /* va_copy() is needed when va_list is an array type */
+    va_copy(ap_copy, ap);
+    obj = qobject_from_jsonv(string, &ap_copy, &error_abort);
+    va_end(ap_copy);
+
+    assert(obj);
+    return obj;
+}
+
+/*
+ * Parse @string as JSON value with %-escapes interpolated.
+ * Abort on error.  Do not use with untrusted @string.
+ * Return the resulting QObject.  It is never null.
  */
-QObject *qobject_from_jsonf(const char *string, ...)
+QObject *qobject_from_jsonf_nofail(const char *string, ...)
 {
     QObject *obj;
     va_list ap;
 
     va_start(ap, string);
-    obj = qobject_from_jsonv(string, &ap, &error_abort);
+    obj = qobject_from_vjsonf_nofail(string, ap);
     va_end(ap);
 
-    assert(obj != NULL);
     return obj;
 }
 
+/*
+ * Parse @string as JSON object with %-escapes interpolated.
+ * Abort on error.  Do not use with untrusted @string.
+ * Return the resulting QDict.  It is never null.
+ */
+QDict *qdict_from_vjsonf_nofail(const char *string, va_list ap)
+{
+    QDict *qdict;
+
+    qdict = qobject_to(QDict, qobject_from_vjsonf_nofail(string, ap));
+    assert(qdict);
+    return qdict;
+}
+
+/*
+ * Parse @string as JSON object with %-escapes interpolated.
+ * Abort on error.  Do not use with untrusted @string.
+ * Return the resulting QDict.  It is never null.
+ */
+QDict *qdict_from_jsonf_nofail(const char *string, ...)
+{
+    QDict *qdict;
+    va_list ap;
+
+    va_start(ap, string);
+    qdict = qdict_from_vjsonf_nofail(string, ap);
+    va_end(ap);
+    return qdict;
+}
+
 typedef struct ToJsonIterState
 {
     int indent;