Added crypto random-number generator

base/rand_util_posix.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/rand_util.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <unistd.h>
 
@@ skipping 23 matching lines @@
  private:
   int fd_;
 };
 
 base::LazyInstance<URandomFd> g_urandom_fd = LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
 namespace base {
 
+// NOTE: This function must be cryptographically secure: crbug.com/140076

[akalin, 2012/08/02 07:01:12]

end with a period.

Prefix with http:// (so it linkifies)

 uint64 RandUint64() {
   uint64 number;
 
   int urandom_fd = g_urandom_fd.Pointer()->fd();
   bool success = file_util::ReadFromFD(urandom_fd,
                                        reinterpret_cast<char*>(&number),
                                        sizeof(number));
   CHECK(success);
 
   return number;
 }
 
 int GetUrandomFD(void) {
   return g_urandom_fd.Pointer()->fd();
 }
 
 }  // namespace base