Revise getRandom facilities

Use one of the following to provide random bytes:
- Windows CryptGenRandom
- Linux getrandom (syscall interface to urandom, without nasty corner
  cases such as file descriptor exhaustion or re-linked /dev/urandom)
- std::device_random (C++ random device, which usually will be urandom)

This also equalizes util::getRandom and SimpleRandomizer (the former
will now use the latter) instead of having essentially two different
PRNG interfaces with potentially different quality.

Closes GH-320

1 files changed, 50 insertions, 0 deletions

diff --git a/src/getrandom_linux.c b/src/getrandom_linux.c
new file mode 100644
index 00000000..85314fd6
--- /dev/null
+++ b/src/getrandom_linux.c
@@ -0,0 +1,50 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2014 Nils Maier
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+
+#define _GNUSOURCE
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <linux/random.h>
+
+#include "config.h"
+#include "getrandom_linux.h"
+
+int getrandom_linux(void *buf, size_t buflen) {
+#ifdef HAVE_GETRANDOM
+  return getrandom(buf, buflen, 0);
+#else // HAVE_GETRANDOM
+  return syscall(SYS_getrandom, buf, buflen, 0);
+#endif // HAVE_GETRANDOM
+}