shared/varlink: add missing terminator in json strings

[thirdparty/systemd.git] / src / shared / json.c

diff --git a/src/shared/json.c b/src/shared/json.c
index 782d80af16aac0a2d77e591bd872b95e445340e2..baea31fed93bada63202267c7e54236ffcb0aa42 100644 (file)
--- a/src/shared/json.c
+++ b/src/shared/json.c
@@ -1555,6 +1555,9 @@ int json_variant_format(JsonVariant *v, JsonFormatFlags flags, char **ret) {
         size_t sz = 0;
         int r;
 
+        /* Returns the length of the generated string (without the terminating NUL),
+         * or negative on error. */
+
         assert_return(v, -EINVAL);
         assert_return(ret, -EINVAL);
 
@@ -1567,6 +1570,9 @@ int json_variant_format(JsonVariant *v, JsonFormatFlags flags, char **ret) {
 
                 json_variant_dump(v, flags, f, NULL);
 
+                /* Add terminating 0, so that the output buffer is a valid string. */
+                fputc('\0', f);
+
                 r = fflush_and_check(f);
         }
         if (r < 0)
@@ -1574,8 +1580,8 @@ int json_variant_format(JsonVariant *v, JsonFormatFlags flags, char **ret) {
 
         assert(s);
         *ret = TAKE_PTR(s);
-
-        return (int) sz;
+        assert(sz > 0);
+        return (int) sz - 1;
 }
 
 void json_variant_dump(JsonVariant *v, JsonFormatFlags flags, FILE *f, const char *prefix) {