Security-57031.1.35.tar.gz

[apple/security.git] / Security / libsecurity_cssm / lib / cssmcontext.h

diff --git a/Security/libsecurity_cssm/lib/cssmcontext.h b/Security/libsecurity_cssm/lib/cssmcontext.h
new file mode 100644 (file)
index 0000000..6f82501
--- /dev/null
+++ b/Security/libsecurity_cssm/lib/cssmcontext.h
@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2000-2004,2011-2012,2014 Apple 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@
+ */
+
+
+//
+// context - manage CSSM (cryptographic) contexts every which way
+//
+#ifndef _H_CSSMCONTEXT
+#define _H_CSSMCONTEXT
+
+#include "cssmint.h"
+#include "cspattachment.h"
+#include <security_cdsa_utilities/context.h>
+
+#ifdef _CPP_CSSMCONTEXT
+# pragma export on
+#endif
+
+
+//
+// A HandleContext adds handle semantics to the Context object.
+// Note that not every Context is a HandleContext - the Contexts we hand
+// to our API customers for fondling are not. Also note that a HandleContext
+// not a PODWrapper.
+// HandleContext has an allocation method taking a Allocator. To destroy
+// a HandleObject, call HandleObject::destroy(the-context, the-allocator).
+// You are responsible for picking the same allocator used on construction.
+//
+// THREADS: HandleContexts are assumed to have single-thread use. That means that
+// operations on HandleContexts are NOT interlocked automatically; two users of
+// the same context must do any arbitration themselves. A HandleContext is howerver
+// safely interlocked against other objects, in particular its CSPAttachment.
+// The upshot is that you're safe using a HandleContext unless someone else is trying
+// to use the same context in parallel.
+//
+class HandleContext : public HandleObject, public Context {
+public:
+    HandleContext(CSPAttachment &attach,
+                  CSSM_CONTEXT_TYPE type,
+                  CSSM_ALGORITHMS algorithmId)
+    : Context(type, algorithmId), attachment(attach), extent(0) { }
+    virtual ~HandleContext();
+
+    CSPAttachment &attachment;
+       
+       using Context::find;    // guard against HandleObjec::find
+
+    void mergeAttributes(const CSSM_CONTEXT_ATTRIBUTE *attributes, uint32 count);
+    CSSM_RETURN validateChange(CSSM_CONTEXT_EVENT event);
+
+    void *operator new (size_t size, Allocator &alloc) throw(std::bad_alloc)
+    { return alloc.malloc(size); }
+    void operator delete (void *addr, size_t, Allocator &alloc) throw()
+    { return alloc.free(addr); }
+    static void destroy(HandleContext *context, Allocator &alloc) throw()
+    { context->~HandleContext(); alloc.free(context); }
+
+    class Maker;       // deluxe builder
+
+#if __GNUC__ > 2
+private:
+    void operator delete (void *addr) throw() { assert(0); }
+#endif
+
+protected:
+    // Locking protocol, courtesy of HandleObject.
+    // This locks the underlying attachment.
+    void lock();
+    bool tryLock();
+
+private:
+    void *extent;                      // extra storage extent in use
+};
+
+inline HandleContext &enterContext(CSSM_CC_HANDLE h)
+{
+    return HandleObject::findAndLock<HandleContext>((CSSM_HANDLE)h, CSSM_ERRCODE_INVALID_CONTEXT_HANDLE);
+}
+
+
+//
+// A Maker is a deluxe wrapper around Builder. It creates whole HandleContext
+// objects in one swell foop, handling object locking, construction, error
+// recovery, and all that jazz. A Maker cannot create plain Context objects.
+//
+class HandleContext::Maker : public Context::Builder {
+public:
+    Maker(CSSM_CSP_HANDLE handle) 
+               : Context::Builder(HandleObject::findAndLock<CSPAttachment>(handle, CSSM_ERRCODE_INVALID_CSP_HANDLE)),
+               attachment(static_cast<CSPAttachment &>(allocator)), // order dependency(!)
+               locker(attachment, true)
+       { attachment.finishEnter(); }
+
+    CSPAttachment &attachment;
+
+    CSSM_CC_HANDLE operator () (CSSM_CONTEXT_TYPE type,
+                                CSSM_ALGORITHMS algorithm);
+                                                               
+private:
+       StLock<CountingMutex, &CountingMutex::enter, &CountingMutex::exit> locker;
+};
+
+#endif //_H_CSSMCONTEXT