1/*
2 * Copyright 2012, The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef BCC_EXECUTION_ENGINE_SYMBOL_RESOLVERS_H
18#define BCC_EXECUTION_ENGINE_SYMBOL_RESOLVERS_H
19
20#include <cstdlib>
21#include <cstring>
22
23#include "SymbolResolverInterface.h"
24
25namespace bcc {
26
27/*
28 * Symbol lookup via dlopen()/dlsym().
29 */
30class DyldSymbolResolver : public SymbolResolverInterface {
31public:
32  typedef void *HandleTy;
33
34private:
35  HandleTy mHandle;
36  char *mError;
37
38public:
39  // If pFileName is NULL, it will search symbol in the current process image.
40  DyldSymbolResolver(const char *pFileName, bool pLazyBinding = true);
41
42  virtual void *getAddress(const char *pName);
43
44  inline bool hasError() const
45  { return (mError != NULL); }
46  inline const char *getError() const
47  { return mError; }
48
49  ~DyldSymbolResolver();
50};
51
52/*
53 * Symbol lookup by searching through an array of SymbolMap.
54 */
55template<typename Subclass>
56class ArraySymbolResolver : public SymbolResolverInterface {
57public:
58  typedef struct {
59    // Symbol name
60    const char *mName;
61    // Symbol address
62    void *mAddr;
63  } SymbolMap;
64
65private:
66  // True if the symbol name is sorted in the array.
67  bool mSorted;
68
69  static int CompareSymbolName(const void *pA, const void *pB) {
70    return ::strcmp(reinterpret_cast<const SymbolMap *>(pA)->mName,
71                    reinterpret_cast<const SymbolMap *>(pB)->mName);
72  }
73
74public:
75  ArraySymbolResolver(bool pSorted = false) : mSorted(pSorted) { }
76
77  virtual void *getAddress(const char *pName) {
78    const SymbolMap *result = NULL;
79
80    if (mSorted) {
81      // Use binary search.
82      const SymbolMap key = { pName, NULL };
83
84      result = reinterpret_cast<SymbolMap *>(
85                   ::bsearch(&key, Subclass::SymbolArray,
86                                   Subclass::NumSymbols,
87                                   sizeof(SymbolMap),
88                                   CompareSymbolName));
89    } else {
90      // Use linear search.
91      for (size_t i = 0; i < Subclass::NumSymbols; i++) {
92        if (::strcmp(Subclass::SymbolArray[i].mName, pName) == 0) {
93          result = &Subclass::SymbolArray[i];
94          break;
95        }
96      }
97    }
98
99    return ((result != NULL) ? result->mAddr : NULL);
100  }
101};
102
103template<typename ContextTy = void *>
104class LookupFunctionSymbolResolver : public SymbolResolverInterface {
105public:
106  typedef void *(*LookupFunctionTy)(ContextTy pContext, const char *pName);
107
108private:
109  LookupFunctionTy mLookupFunc;
110  ContextTy mContext;
111
112public:
113  LookupFunctionSymbolResolver(LookupFunctionTy pLookupFunc = NULL,
114                               ContextTy pContext = NULL)
115    : mLookupFunc(pLookupFunc), mContext(pContext) { }
116
117  virtual void *getAddress(const char *pName) {
118    return ((mLookupFunc != NULL) ? mLookupFunc(mContext, pName) : NULL);
119  }
120
121  inline LookupFunctionTy getLookupFunction() const
122  { return mLookupFunc; }
123  inline ContextTy getContext() const
124  { return mContext; }
125
126  inline void setLookupFunction(LookupFunctionTy pLookupFunc)
127  { mLookupFunc = pLookupFunc; }
128  inline void setContext(ContextTy pContext)
129  { mContext = pContext; }
130};
131
132} // end namespace bcc
133
134#endif // BCC_EXECUTION_ENGINE_SYMBOL_RESOLVERS_H
135