avoid 0-sized, unused allocations

diff --git a/libraries/librewrite/subst.c b/libraries/librewrite/subst.c
index 4c0bc411e0fa627c0d77084e2a116da33c635f06..a6d9fdbabf9bcfa89541c38342abc377afac60f7 100644 (file)
--- a/libraries/librewrite/subst.c
+++ b/libraries/librewrite/subst.c
@@ -300,10 +300,12 @@ rewrite_subst_apply(
        /*
         * Prepare room for submatch expansion
         */
-       submatch = calloc( sizeof( struct berval ),
-                       subst->lt_num_submatch );
-       if ( submatch == NULL ) {
-               return REWRITE_REGEXEC_ERR;
+       if ( subst->lt_num_submatch > 0 ) {
+               submatch = calloc( sizeof( struct berval ),
+                               subst->lt_num_submatch );
+               if ( submatch == NULL ) {
+                       return REWRITE_REGEXEC_ERR;
+               }
        }
        
        /*
@@ -408,8 +410,8 @@ rewrite_subst_apply(
        l += subst->lt_subs_len;
        res = calloc( sizeof( char ), l + 1 );
        if ( res == NULL ) {
-               free( submatch );
-               return REWRITE_REGEXEC_ERR;
+               rc = REWRITE_REGEXEC_ERR;
+               goto cleanup;
        }
 
        /*
@@ -433,7 +435,12 @@ rewrite_subst_apply(
 
        val->bv_val = res;
        val->bv_len = l;
-       
+
+cleanup:;
+       if ( submatch ) {
+               free( submatch );
+       }
+
        return rc;
 }