jshn: add error handling and fix memory leak in jshn_format().

Though currently jshn is more a one-shot data transformation tool and
won't leak much memory in its lifetime, people may use it as example
code, so do it right.

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

diff --git a/jshn.c b/jshn.c
index 431e1b3..69cb06f 100644 (file)
--- a/jshn.c
+++ b/jshn.c
@@ -258,18 +258,31 @@ static int jshn_format(bool no_newline, bool indent)
 {
        json_object *obj;
        const char *output;
+       char *blobmsg_output = NULL;
+       int ret = -1;
+
+       if (!(obj = json_object_new_object()))
+               return -1;
 
-       obj = json_object_new_object();
        jshn_add_objects(obj, "J_V", false);
-       output = json_object_to_json_string(obj);
+       if (!(output = json_object_to_json_string(obj)))
+               goto out;
+
        if (indent) {
                blob_buf_init(&b, 0);
-               blobmsg_add_json_from_string(&b, output);
-               output = blobmsg_format_json_indent(b.head, 1, 0);
+               if (!blobmsg_add_json_from_string(&b, output))
+                       goto out;
+               if (!(blobmsg_output = blobmsg_format_json_indent(b.head, 1, 0)))
+                       goto out;
+               output = blobmsg_output;
        }
        fprintf(stdout, "%s%s", output, no_newline ? "" : "\n");
+       free(blobmsg_output);
+       ret = 0;
+
+out:
        json_object_put(obj);
-       return 0;
+       return ret;
 }
 
 static int usage(const char *progname)