1/*
2 * Copyright (c) 2000-2004 Apple Computer, Inc. All Rights Reserved.
3 *
4 * @APPLE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. Please obtain a copy of the License at
10 * http://www.opensource.apple.com/apsl/ and read it before using this
11 * file.
12 *
13 * The Original Code and all software distributed under the License are
14 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
15 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
16 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
18 * Please see the License for the specific language governing rights and
19 * limitations under the License.
20 *
21 * @APPLE_LICENSE_HEADER_END@
22 */
23
24
25//
26// context - manage CSSM (cryptographic) contexts every which way
27//
28#ifndef _H_CSSMCONTEXT
29#define _H_CSSMCONTEXT
30
31#include "cssmint.h"
32#include "cspattachment.h"
33#include <security_cdsa_utilities/context.h>
34
35#ifdef _CPP_CSSMCONTEXT
36# pragma export on
37#endif
38
39
40//
41// A HandleContext adds handle semantics to the Context object.
42// Note that not every Context is a HandleContext - the Contexts we hand
43// to our API customers for fondling are not. Also note that a HandleContext
44// not a PODWrapper.
45// HandleContext has an allocation method taking a Allocator. To destroy
46// a HandleObject, call HandleObject::destroy(the-context, the-allocator).
47// You are responsible for picking the same allocator used on construction.
48//
49// THREADS: HandleContexts are assumed to have single-thread use. That means that
50// operations on HandleContexts are NOT interlocked automatically; two users of
51// the same context must do any arbitration themselves. A HandleContext is howerver
52// safely interlocked against other objects, in particular its CSPAttachment.
53// The upshot is that you're safe using a HandleContext unless someone else is trying
54// to use the same context in parallel.
55//
56class HandleContext : public HandleObject, public Context {
57public:
58    HandleContext(CSPAttachment &attach,
59                  CSSM_CONTEXT_TYPE type,
60                  CSSM_ALGORITHMS algorithmId)
61    : Context(type, algorithmId), attachment(attach), extent(0) { }
62    virtual ~HandleContext();
63
64    CSPAttachment &attachment;
65
66	using Context::find;	// guard against HandleObjec::find
67
68    void mergeAttributes(const CSSM_CONTEXT_ATTRIBUTE *attributes, uint32 count);
69    CSSM_RETURN validateChange(CSSM_CONTEXT_EVENT event);
70
71    void *operator new (size_t size, Allocator &alloc) throw(std::bad_alloc)
72    { return alloc.malloc(size); }
73    void operator delete (void *addr, size_t, Allocator &alloc) throw()
74    { return alloc.free(addr); }
75    static void destroy(HandleContext *context, Allocator &alloc) throw()
76    { context->~HandleContext(); alloc.free(context); }
77
78    class Maker;	// deluxe builder
79
80#if __GNUC__ > 2
81private:
82    void operator delete (void *addr) throw() { assert(0); }
83#endif
84
85protected:
86    // Locking protocol, courtesy of HandleObject.
87    // This locks the underlying attachment.
88    void lock();
89    bool tryLock();
90
91private:
92    void *extent;			// extra storage extent in use
93};
94
95inline HandleContext &enterContext(CSSM_CC_HANDLE h)
96{
97    return HandleObject::findAndLock<HandleContext>((CSSM_HANDLE)h, CSSM_ERRCODE_INVALID_CONTEXT_HANDLE);
98}
99
100
101//
102// A Maker is a deluxe wrapper around Builder. It creates whole HandleContext
103// objects in one swell foop, handling object locking, construction, error
104// recovery, and all that jazz. A Maker cannot create plain Context objects.
105//
106class HandleContext::Maker : public Context::Builder {
107public:
108    Maker(CSSM_CSP_HANDLE handle)
109		: Context::Builder(HandleObject::findAndLock<CSPAttachment>(handle, CSSM_ERRCODE_INVALID_CSP_HANDLE)),
110		attachment(static_cast<CSPAttachment &>(allocator)), // order dependency(!)
111		locker(attachment, true)
112	{ attachment.finishEnter(); }
113
114    CSPAttachment &attachment;
115
116    CSSM_CC_HANDLE operator () (CSSM_CONTEXT_TYPE type,
117                                CSSM_ALGORITHMS algorithm);
118
119private:
120	StLock<CountingMutex, &CountingMutex::enter, &CountingMutex::exit> locker;
121};
122
123#endif //_H_CSSMCONTEXT
124