fuzzers/fuzzer_json: add simple fuzzing for our json code

fuzzers/fuzzer_json.c

@@ -0,0 +1,44 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * mpv is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "common.h"
+
+#include "misc/json.h"
+#include "mpv_talloc.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+    void *tmp = talloc_new(NULL);
+    char *s = talloc_array_ptrtype(tmp, s, size + 1);
+    memcpy(s, data, size);
+    s[size] = '\0';
+
+    json_skip_whitespace(&s);
+
+    struct mpv_node res;
+    if (!json_parse(tmp, &res, &s, MAX_JSON_DEPTH)) {
+        char *d = talloc_strdup(tmp, "");
+        json_write(&d, &res);
+
+        d[0] = '\0';
+        json_write_pretty(&d, &res);
+    }
+
+    talloc_free(tmp);
+
+    return 0;
+}

fuzzers/meson.build

@@ -76,4 +76,9 @@ fuzzers += executable('fuzzer_options_parser', 'fuzzer_options_parser.c',
                       objects: libmpv.extract_all_objects(recursive: true),
                       dependencies: dependencies)
 
+fuzzers += executable('fuzzer_json', 'fuzzer_json.c',
+                      link_language: 'cpp', include_directories: incdir,
+                      objects: libmpv.extract_all_objects(recursive: true),
+                      dependencies: dependencies)
+
 alias_target('fuzzers', fuzzers)