Security-55163.44.tar.gz

[apple/security.git] / libsecurity_utilities / lib / devrandom.cpp

diff --git a/libsecurity_utilities/lib/devrandom.cpp b/libsecurity_utilities/lib/devrandom.cpp
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+/*
+ * Copyright (c) 2000-2004 Apple Computer, Inc. All Rights Reserved.
+ * 
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+
+//
+// devrandom - RNG operations based on /dev/random
+//
+#include <security_utilities/devrandom.h>
+#include <security_utilities/logging.h>
+
+using namespace UnixPlusPlus;
+
+
+namespace Security {
+
+
+//
+// The common (shared) open file descriptor to /dev/random
+//
+ModuleNexus<DevRandomGenerator::Readonly> DevRandomGenerator::mReader;
+ModuleNexus<DevRandomGenerator::Writable> DevRandomGenerator::mWriter;
+
+
+//
+// In the current implementation, opening the file descriptor is deferred.
+//
+DevRandomGenerator::DevRandomGenerator(bool writable)
+{
+}
+
+
+//
+// Standard generate (directly from /dev/random)
+//
+void DevRandomGenerator::random(void *data, size_t length)
+{
+    try {
+               size_t bytesRead = mReader().read(data, length);
+               if (bytesRead != length) {      // short read (shouldn't happen)
+                       Syslog::error("DevRandomGenerator: wanted %ld got %ld bytes",
+                               length, bytesRead);
+                       UnixError::throwMe(EIO);
+               }
+       } catch(const UnixError &uerr) {
+               Syslog::error("DevRandomGenerator: error %d reading /dev/random",
+                       uerr.error);
+               throw;
+       }
+}
+
+
+//
+// If you opened for writing, you add entropy to the global pool here
+//
+void DevRandomGenerator::addEntropy(const void *data, size_t length)
+{
+    if (mWriter().write(data, length) != length)
+               UnixError::throwMe(EIO);        // short write (shouldn't happen)
+}
+
+
+}      // end namespace Security