ARC: give more detail with "bad signing-spec" message

diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt
index 3389632a2eeac6b82a990a33a36924c6b213693c..bc5bab77d4ab7aa715d2feee2789bbc9e1d50b93 100644 (file)
--- a/doc/doc-txt/experimental-spec.txt
+++ b/doc/doc-txt/experimental-spec.txt
@@ -802,7 +802,8 @@ arc_sign = <admd-identifier> : <selector> : <privkey>
 An option on the smtp transport, which constructs and prepends to the message
 an ARC set of headers.  The textually-first Authentication-Results: header
 is used as a basis (you must have added one on entry to the ADMD).
-Expanded; if unset, empty or forced-failure then no signing is done.
+Expanded as a whole; if unset, empty or forced-failure then no signing is done.
+If it is set, all three elements must be non-empty.
 
 
 

diff --git a/src/src/arc.c b/src/src/arc.c
index f4ae096bc26731a6dbd15eb19dcb15392c59c75b..eb143b697486627119076503ddd74777d714056e 100644 (file)
--- a/src/src/arc.c
+++ b/src/src/arc.c
@@ -1536,7 +1536,8 @@ selector = string_nextinlist(&signspec, &sep, NULL, 0);
 if (  !*identity | !*selector
    || !(privkey = string_nextinlist(&signspec, &sep, NULL, 0)) || !*privkey)
   {
-  log_write(0, LOG_MAIN|LOG_PANIC, "ARC: bad signing-specification");
+  log_write(0, LOG_MAIN|LOG_PANIC, "ARC: bad signing-specification (%s)",
+    !*identity ? "identity" : !*selector ? "selector" : "private-key");
   return NULL;
   }
 if (*privkey == '/' && !(privkey = expand_file_big_buffer(privkey)))