A little library for patching symbols at runtime.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@5296 a95241bf-73f2-0310-859d-f6bbb57e9c96
2003-11-10 00:38:35 +00:00
parent 51fde20c1e
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+//------------------------------------------------------------------------------
+//	Copyright (c) 2003, Ingo Weinhold
+//
+//	Permission is hereby granted, free of charge, to any person obtaining a
+//	copy of this software and associated documentation files (the "Software"),
+//	to deal in the Software without restriction, including without limitation
+//	the rights to use, copy, modify, merge, publish, distribute, sublicense,
+//	and/or sell copies of the Software, and to permit persons to whom the
+//	Software is furnished to do so, subject to the following conditions:
+//
+//	The above copyright notice and this permission notice shall be included in
+//	all copies or substantial portions of the Software.
+//
+//	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+//	FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+//	DEALINGS IN THE SOFTWARE.
+//
+//	File Name:		ElfSymbolPatcher.h
+//	Author:			Ingo Weinhold ([email protected])
+//	Description:	Interface declaration of classes used for patching ELF
+//					symbols. Central class is ElfSymbolPatcher. It is a kind of
+//					roster, managing all necessary infos (loaded images) and
+//					being able to fill ElfSymbolPatchInfos with life.
+//					An ElfSymbolPatchInfo represents a symbol and is able to
+//					patch/restore it. An ElfSymbolPatchGroup bundles several
+//					ElfSymbolPatchInfos and can update their data, e.g.
+//					when images are loaded/unloaded. It uses a
+//					ElfSymbolPatcher internally and provides a more convenient
+//					API for the user.
+//------------------------------------------------------------------------------
+
+#ifndef ELF_SYMBOL_PATCHER_H
+#define ELF_SYMBOL_PATCHER_H
+
+#include <List.h>
+#include <String.h>
+
+class ElfImage;
+class ElfSymbolPatcher;
+class ElfSymbolPatchGroup;
+
+// ElfSymbolPatchInfo
+class ElfSymbolPatchInfo {
+public:
+								ElfSymbolPatchInfo();
+								~ElfSymbolPatchInfo();
+
+			status_t			InitCheck() const;
+
+			const char*			GetSymbolName() const;
+			void*				GetOriginalAddress() const;
+			image_id			GetOriginalAddressImage() const;
+
+			status_t			Patch(void* newAddress);
+			status_t			Restore();
+
+private:
+			class Entry;
+
+private:
+			void				Unset();
+			status_t			SetSymbolName(const char* name);
+			void				SetOriginalAddress(void* address,
+												   image_id image);
+			status_t			CreateEntry(image_id image, BList* targets);
+			bool				DeleteEntry(image_id image);
+			Entry*				EntryAt(int32 index);
+			Entry*				EntryFor(image_id image);
+
+private:
+			friend class ElfSymbolPatcher;
+			friend class ElfSymbolPatchGroup;
+
+			BString				fSymbolName;
+			void*				fOriginalAddress;
+			image_id			fOriginalAddressImage;
+			BList				fEntries;
+};
+
+// ElfSymbolPatcher
+class ElfSymbolPatcher {
+public:
+			class UpdateAdapter;
+
+public:
+								ElfSymbolPatcher();
+								~ElfSymbolPatcher();
+
+			status_t			InitCheck() const;
+			status_t			Update(UpdateAdapter* updateAdapter = NULL);
+			void				Unload();
+
+			status_t			GetSymbolPatchInfo(const char* symbolName,
+												   ElfSymbolPatchInfo* info);
+			status_t			UpdateSymbolPatchInfo(ElfSymbolPatchInfo* info,
+													  ElfImage* image);
+
+private:
+			status_t			_Init();
+			void				_Cleanup();
+
+			ElfImage*			_ImageAt(int32 index) const;
+			ElfImage*			_ImageForID(image_id id) const;
+
+private:
+			BList				fImages;
+			status_t			fInitStatus;
+};
+
+// UpdateAdapter
+class ElfSymbolPatcher::UpdateAdapter {
+public:
+								UpdateAdapter();
+	virtual						~UpdateAdapter();
+
+	virtual	void				ImageAdded(ElfImage* image);
+	virtual	void				ImageRemoved(ElfImage* image);
+};
+
+
+// ElfSymbolPatchGroup
+class ElfSymbolPatchGroup : private ElfSymbolPatcher::UpdateAdapter {
+public:
+								ElfSymbolPatchGroup(
+									ElfSymbolPatcher* patcher = NULL);
+								~ElfSymbolPatchGroup();
+
+			ElfSymbolPatcher*	GetPatcher() const	{ return fPatcher; }
+
+			status_t			AddPatch(const char* symbolName,
+										 void* newAddress,
+										 void** originalAddress);
+
+			void				RemoveAllPatches();
+
+			status_t			Patch();
+			status_t			Restore();
+
+			status_t			Update();
+
+private:
+			class PatchInfo : public ElfSymbolPatchInfo {
+			public:
+				void*			fNewAddress;
+			};
+
+private:
+	virtual	void				ImageAdded(ElfImage* image);
+	virtual	void				ImageRemoved(ElfImage* image);
+
+private:
+			ElfSymbolPatcher*	fPatcher;
+			BList				fPatchInfos;
+			bool				fOwnsPatcher;
+			bool				fPatched;
+};
+
+#endif	// ELF_SYMBOL_PATCHER_H