1//------------------------------------------------------------------------------
2//	Copyright (c) 2003, Ingo Weinhold
3//
4//	Permission is hereby granted, free of charge, to any person obtaining a
5//	copy of this software and associated documentation files (the "Software"),
6//	to deal in the Software without restriction, including without limitation
7//	the rights to use, copy, modify, merge, publish, distribute, sublicense,
8//	and/or sell copies of the Software, and to permit persons to whom the
9//	Software is furnished to do so, subject to the following conditions:
10//
11//	The above copyright notice and this permission notice shall be included in
12//	all copies or substantial portions of the Software.
13//
14//	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15//	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16//	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17//	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18//	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
19//	FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
20//	DEALINGS IN THE SOFTWARE.
21//
22//	File Name:		ElfSymbolPatcher.h
23//	Author:			Ingo Weinhold (bonefish@users.sf.net)
24//	Description:	Interface declaration of classes used for patching ELF
25//					symbols. Central class is ElfSymbolPatcher. It is a kind of
26//					roster, managing all necessary infos (loaded images) and
27//					being able to fill ElfSymbolPatchInfos with life.
28//					An ElfSymbolPatchInfo represents a symbol and is able to
29//					patch/restore it. An ElfSymbolPatchGroup bundles several
30//					ElfSymbolPatchInfos and can update their data, e.g.
31//					when images are loaded/unloaded. It uses a
32//					ElfSymbolPatcher internally and provides a more convenient
33//					API for the user.
34//------------------------------------------------------------------------------
35
36#ifndef ELF_SYMBOL_PATCHER_H
37#define ELF_SYMBOL_PATCHER_H
38
39#include <List.h>
40#include <String.h>
41
42
43namespace SymbolPatcher {
44
45class ElfImage;
46class ElfSymbolPatcher;
47class ElfSymbolPatchGroup;
48
49// ElfSymbolPatchInfo
50class ElfSymbolPatchInfo {
51public:
52								ElfSymbolPatchInfo();
53								~ElfSymbolPatchInfo();
54
55			status_t			InitCheck() const;
56
57			const char*			GetSymbolName() const;
58			void*				GetOriginalAddress() const;
59			image_id			GetOriginalAddressImage() const;
60
61			status_t			Patch(void* newAddress);
62			status_t			Restore();
63
64private:
65			class Entry;
66
67private:
68			void				Unset();
69			status_t			SetSymbolName(const char* name);
70			void				SetOriginalAddress(void* address,
71												   image_id image);
72			status_t			CreateEntry(image_id image, BList* targets);
73			bool				DeleteEntry(image_id image);
74			Entry*				EntryAt(int32 index);
75			Entry*				EntryFor(image_id image);
76
77private:
78			friend class ElfSymbolPatcher;
79			friend class ElfSymbolPatchGroup;
80
81			BString				fSymbolName;
82			void*				fOriginalAddress;
83			image_id			fOriginalAddressImage;
84			BList				fEntries;
85};
86
87// ElfSymbolPatcher
88class ElfSymbolPatcher {
89public:
90			class UpdateAdapter;
91
92public:
93								ElfSymbolPatcher();
94								~ElfSymbolPatcher();
95
96			status_t			InitCheck() const;
97			status_t			Update(UpdateAdapter* updateAdapter = NULL);
98			void				Unload();
99
100			status_t			GetSymbolPatchInfo(const char* symbolName,
101												   ElfSymbolPatchInfo* info);
102			status_t			UpdateSymbolPatchInfo(ElfSymbolPatchInfo* info,
103													  ElfImage* image);
104
105private:
106			status_t			_Init();
107			void				_Cleanup();
108
109			ElfImage*			_ImageAt(int32 index) const;
110			ElfImage*			_ImageForID(image_id id) const;
111
112private:
113			BList				fImages;
114			status_t			fInitStatus;
115};
116
117// UpdateAdapter
118class ElfSymbolPatcher::UpdateAdapter {
119public:
120								UpdateAdapter();
121	virtual						~UpdateAdapter();
122
123	virtual	void				ImageAdded(ElfImage* image);
124	virtual	void				ImageRemoved(ElfImage* image);
125};
126
127
128// ElfSymbolPatchGroup
129class ElfSymbolPatchGroup : private ElfSymbolPatcher::UpdateAdapter {
130public:
131								ElfSymbolPatchGroup(
132									ElfSymbolPatcher* patcher = NULL);
133								~ElfSymbolPatchGroup();
134
135			ElfSymbolPatcher*	GetPatcher() const	{ return fPatcher; }
136
137			status_t			AddPatch(const char* symbolName,
138										 void* newAddress,
139										 void** originalAddress);
140
141			void				RemoveAllPatches();
142
143			status_t			Patch();
144			status_t			Restore();
145
146			status_t			Update();
147
148private:
149			class PatchInfo : public ElfSymbolPatchInfo {
150			public:
151				void*			fNewAddress;
152			};
153
154private:
155	virtual	void				ImageAdded(ElfImage* image);
156	virtual	void				ImageRemoved(ElfImage* image);
157
158private:
159			ElfSymbolPatcher*	fPatcher;
160			BList				fPatchInfos;
161			bool				fOwnsPatcher;
162			bool				fPatched;
163};
164
165} // namespace SymbolPatcher
166
167using namespace SymbolPatcher;
168
169
170#endif	// ELF_SYMBOL_PATCHER_H
171