ruby.h: safe_level check

* include/ruby/ruby.h (RUBY_SAFE_LEVEL_CHECK): check constant safe
  level at compile time.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41273 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Thu Jun 13 14:51:06 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* include/ruby/ruby.h (RUBY_SAFE_LEVEL_CHECK): check constant safe
+	  level at compile time.
+
 Thu Jun 13 14:39:08 2013  Shugo Maeda  <shugo@ruby-lang.org>
 
 	* test/-ext-/test_printf.rb, test/rss/test_parser.rb,

include/ruby/ruby.h

@@ -556,9 +556,20 @@ VALUE rb_get_path(VALUE);
 VALUE rb_get_path_no_checksafe(VALUE);
 #define FilePathStringValue(v) ((v) = rb_get_path_no_checksafe(v))
 
+#define RUBY_SAFE_LEVEL_MAX 3
 void rb_secure(int);
 int rb_safe_level(void);
 void rb_set_safe_level(int);
+#if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
+int ruby$safe_level$4(void) __attribute__((error("$SAFE=4 is obsolete")));
+#define RUBY_SAFE_LEVEL_INVALID_P(level) \
+    __extension__(__builtin_constant_p(level) && \
+		  ((level) < 0 || RUBY_SAFE_LEVEL_MAX < (level)))
+#define RUBY_SAFE_LEVEL_CHECK(level) \
+    (RUBY_SAFE_LEVEL_INVALID_P(level) ? ruby$safe_level$4() : 0)
+#define rb_secure(level) (RUBY_SAFE_LEVEL_CHECK(level), rb_secure(level))
+#define rb_set_safe_level(level) (RUBY_SAFE_LEVEL_CHECK(level), rb_set_safe_level(level))
+#endif
 void rb_set_safe_level_force(int);
 void rb_secure_update(VALUE);
 NORETURN(void rb_insecure_operation(void));

safe.c

@@ -16,13 +16,16 @@
    3 - all generated objects are tainted
 */
 
-#define SAFE_LEVEL_MAX 3
+#define SAFE_LEVEL_MAX RUBY_SAFE_LEVEL_MAX
 
 #include "ruby/ruby.h"
 #include "vm_core.h"
 
 /* $SAFE accessor */
 
+#undef rb_secure
+#undef rb_set_safe_level
+
 int
 rb_safe_level(void)
 {