zend: introducing ZEND_ELEMENT_COUNT for struct's dynamic arrays.

It is mostly for ubsan and helping array bound checking.

Author: devnexen

Zend/zend_portability.h

@@ -327,6 +327,14 @@ char *alloca();
 # define HAVE_BUILTIN_CONSTANT_P
 #endif
 
+#if __has_attribute(element_count)
+#define ZEND_ELEMENT_COUNT(m) __attribute__((element_count(m)))
+#elif __has_attribute(counted_by)
+#define ZEND_ELEMENT_COUNT(m) __attribute__((counted_by(m)))
+#else
+#define ZEND_ELEMENT_COUNT(m)
+#endif
+
 #ifdef HAVE_BUILTIN_CONSTANT_P
 # define ZEND_CONST_COND(_condition, _default) \
 	(__builtin_constant_p(_condition) ? (_condition) : (_default))

sapi/fpm/fpm/fpm_scoreboard.h

@@ -67,7 +67,7 @@ struct fpm_scoreboard_s {
 	int free_proc;
 	unsigned long int slow_rq;
 	struct fpm_scoreboard_s *shared;
-	struct fpm_scoreboard_proc_s procs[];
+	struct fpm_scoreboard_proc_s procs[] ZEND_ELEMENT_COUNT(nprocs);
 };
 
 int fpm_scoreboard_init_main(void);