Change fr_vlog_perror() behavior in what might be an edge case (#5153)

As things stand, if the error stack is non-empty and fmt is null,
the copy of f_rules->first_prefix to sbuff won't make any
difference.

diff --git a/src/lib/util/log.c b/src/lib/util/log.c
index a7b4ef16f0830a360ebe5cdb05c6e3cf04441f79..21918d48af211540389fce4c10a8822d14b8de65 100644 (file)
--- a/src/lib/util/log.c
+++ b/src/lib/util/log.c
@@ -664,33 +664,25 @@ void fr_vlog_perror(fr_log_t const *log, fr_log_type_t type, char const *file, i
         *      i.e. <msg>: <error>
         */
        error = fr_strerror_pop();
-       if (error) {
-               if (fmt) {
-                       va_list aq;
 
-                       va_copy(aq, ap);
-                       fr_sbuff_in_vsprintf(&sbuff, fmt, aq);
-                       va_end(aq);
+       if (!error && !fmt) return;     /* NOOP */
 
-                       /* coverity[check_return] */
-                       fr_sbuff_in_strcpy(&sbuff, ": ");
-                       /* coverity[check_return] */
-                       fr_sbuff_in_strcpy(&sbuff, error);      /* may not be talloced with const */
-                       error = fr_sbuff_start(&sbuff);
-               }
-       /*
-        *      No error, just print the fmt string
-        */
-       } else {
+       if (fmt) {
                va_list aq;
 
-               if (!fmt) return;       /* NOOP */
-
                va_copy(aq, ap);
-               fr_sbuff_in_vsprintf(&sbuff, fmt, ap);
+               fr_sbuff_in_vsprintf(&sbuff, fmt, aq);
                va_end(aq);
+       }
 
-               error = fr_sbuff_start(&sbuff);
+       if (error && (fmt || f_rules->first_prefix)) {
+               if (fmt) {
+                       /* coverity[check_return] */
+                       fr_sbuff_in_strcpy(&sbuff, ": ");
+               }
+               /* coverity[check_return] */
+               fr_sbuff_in_strcpy(&sbuff, error);
+               error = fr_sbuff_start(&sbuff);         /* may not be talloced with const */
        }
 
        /*