random.c: get rid of blocking

* random.c (fill_random_bytes_syscall): get rid of blocking when
  no entropy is available.  based on the patch by mame in
  [ruby-core:70114].  [Bug #11395]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51374 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Sat Jul 25 21:03:45 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* random.c (fill_random_bytes_syscall): get rid of blocking when
+	  no entropy is available.  based on the patch by mame in
+	  [ruby-core:70114].  [Bug #11395]
+
 Sat Jul 25 11:05:31 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* string.c (str_replace_shared_without_enc): fill the terminator

random.c

@@ -516,6 +516,12 @@ fill_random_bytes_syscall(void *seed, size_t size)
     return 0;
 }
 #elif defined __linux__ && defined SYS_getrandom
+#include <linux/random.h>
+
+# ifndef GRND_NONBLOCK
+#   define GRND_NONBLOCK 0x0001	/* not defined in musl libc */
+# endif
+
 static int
 fill_random_bytes_syscall(void *seed, size_t size)
 {
@@ -523,7 +529,7 @@ fill_random_bytes_syscall(void *seed, size_t size)
     if (try_syscall) {
 	long ret;
 	errno = 0;
-	ret = syscall(SYS_getrandom, seed, size, 0);
+	ret = syscall(SYS_getrandom, seed, size, GRND_NONBLOCK);
 	if (errno == ENOSYS) {
 	    try_syscall = 0;
 	    return -1;