ITS#5747: Only use C99 flexible array member when supported

diff --git a/servers/slapd/overlays/collect.c b/servers/slapd/overlays/collect.c
index 4852022f95da3d793ccab842c0212ad8d219426e..680fb9b59f8309a55d00c46409eac3b39acccb89 100644 (file)
--- a/servers/slapd/overlays/collect.c
+++ b/servers/slapd/overlays/collect.c
@@ -42,11 +42,20 @@
  * is no effect. If no attribute was configured, there is no effect.
  */
 
+/* Use C99 flexible array member if supported, C89 "struct hack" otherwise. */
+#define FLEXIBLE_STRUCT_SIZE(stype, mtype, mcount) \
+       (sizeof(stype) + sizeof(mtype) * ((mcount) - (0 FLEXIBLE_ARRAY_MEMBER)))
+#if __STDC_VERSION__>=199901L || (defined __GNUC__ && !defined __STRICT_ANSI__)
+#define FLEXIBLE_ARRAY_MEMBER
+#else
+#define FLEXIBLE_ARRAY_MEMBER +1
+#endif
+
 typedef struct collect_info {
        struct collect_info *ci_next;
        struct berval ci_dn;
        int ci_ad_num;
-       AttributeDescription *ci_ad[];
+       AttributeDescription *ci_ad[FLEXIBLE_ARRAY_MEMBER];
 } collect_info;
 
 /*
@@ -175,8 +184,8 @@ collect_cf( ConfigArgs *c )
                }
 
                /* allocate config info with room for attribute array */
-               ci = ch_malloc( sizeof( collect_info ) +
-                       ( sizeof (AttributeDescription *) * (count + 1)));
+               ci = ch_malloc( FLEXIBLE_STRUCT_SIZE( collect_info,
+                       AttributeDescription *, count + 1 ));
 
                /* validate and normalize dn */
                ber_str2bv( c->argv[1], 0, 0, &bv );