Security-55163.44.tar.gz

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

diff --git a/libsecurity_utilities/lib/alloc.cpp b/libsecurity_utilities/lib/alloc.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@
+ */
+
+
+//
+// cssmalloc - memory allocation in the CDSA world.
+//
+// Don't eat heavily before inspecting this code.
+//
+#include <security_utilities/alloc.h>
+#include <security_utilities/memutils.h>
+#include <security_utilities/globalizer.h>
+#include <stdlib.h>
+#include <errno.h>
+
+using LowLevelMemoryUtilities::alignof;
+using LowLevelMemoryUtilities::increment;
+using LowLevelMemoryUtilities::alignUp;
+
+extern "C" size_t malloc_size(void *);
+
+
+//
+// Features of the Allocator root class
+//
+bool Allocator::operator == (const Allocator &alloc) const throw()
+{
+       return this == &alloc;
+}
+
+Allocator::~Allocator()
+{
+}
+
+
+//
+// Standard Allocator variants.
+// Note that all calls to Allocator::standard(xxx) with the same xxx argument
+// must produce compatible allocators (i.e. they must be work on a common memory
+// pool). This is trivially achieved here by using singletons.
+//
+struct DefaultAllocator : public Allocator {
+       void *malloc(size_t size) throw(std::bad_alloc);
+       void free(void *addr) throw();
+       void *realloc(void *addr, size_t size) throw(std::bad_alloc);
+};
+
+struct SensitiveAllocator : public DefaultAllocator {
+    void free(void *addr) throw();
+    void *realloc(void *addr, size_t size) throw(std::bad_alloc);
+};
+
+struct DefaultAllocators {
+    DefaultAllocator standard;
+    SensitiveAllocator sensitive;
+};
+
+static ModuleNexus<DefaultAllocators> defaultAllocators;
+
+
+Allocator &Allocator::standard(UInt32 request)
+{
+    switch (request) {
+    case normal:
+        return defaultAllocators().standard;
+    case sensitive:
+        return defaultAllocators().sensitive;
+    default:
+        UnixError::throwMe(ENOMEM);
+    }
+}
+
+void *DefaultAllocator::malloc(size_t size) throw(std::bad_alloc)
+{
+       if (void *result = ::malloc(size))
+               return result;
+       throw std::bad_alloc();
+}
+
+void DefaultAllocator::free(void *addr) throw()
+{
+       ::free(addr);
+}
+
+void *DefaultAllocator::realloc(void *addr, size_t newSize) throw(std::bad_alloc)
+{
+       if (void *result = ::realloc(addr, newSize))
+               return result;
+       throw std::bad_alloc();
+}
+
+void SensitiveAllocator::free(void *addr) throw()
+{
+    memset(addr, 0, malloc_size(addr));
+    DefaultAllocator::free(addr);
+}
+
+void *SensitiveAllocator::realloc(void *addr, size_t newSize) throw(std::bad_alloc)
+{
+    size_t oldSize = malloc_size(addr);
+    if (newSize < oldSize)
+        memset(increment(addr, newSize), 0, oldSize - newSize);
+    return DefaultAllocator::realloc(addr, newSize);
+}
+
+
+//
+// Memory allocators for CssmHeap objects.
+// This implementation stores a pointer to the allocator used into memory
+// *after* the object's proper storage block. This allows the usual free()
+// functions to safely free our (hidden) pointer without knowing about it.
+// An allocator argument of NULL is interpreted as the standard allocator.
+//
+void *CssmHeap::operator new (size_t size, Allocator *alloc) throw(std::bad_alloc)
+{
+       if (alloc == NULL)
+               alloc = &Allocator::standard();
+       size = alignUp(size, alignof<Allocator *>());
+       size_t totalSize = size + sizeof(Allocator *);
+       void *addr = alloc->malloc(totalSize);
+       *(Allocator **)increment(addr, size) = alloc;
+       return addr;
+}
+
+void CssmHeap::operator delete (void *addr, size_t size, Allocator *alloc) throw()
+{
+       alloc->free(addr);      // as per C++ std, called (only) if construction fails
+}
+
+void CssmHeap::operator delete (void *addr, size_t size) throw()
+{
+       void *end = increment(addr, alignUp(size, alignof<Allocator *>()));
+       (*(Allocator **)end)->free(addr);
+}
+
+
+//
+// CssmVector
+//