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      1 /*
      2  * Copyright (C) 2010 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 __PLUGIN_MANAGER_H__
     18 #define __PLUGIN_MANAGER_H__
     19 
     20 #include <dlfcn.h>
     21 #include <sys/types.h>
     22 #include <dirent.h>
     23 
     24 #include <utils/String8.h>
     25 #include <utils/Vector.h>
     26 #include <utils/KeyedVector.h>
     27 
     28 namespace android {
     29 
     30 const char* const PLUGIN_MANAGER_CREATE = "create";
     31 const char* const PLUGIN_MANAGER_DESTROY = "destroy";
     32 const char* const PLUGIN_EXTENSION = ".so";
     33 
     34 /**
     35  * This is the template class for Plugin manager.
     36  *
     37  * The DrmManager uses this class to handle the plugins.
     38  *
     39  */
     40 template<typename Type>
     41 class TPlugInManager {
     42 private:
     43     typedef void*      HANDLE;
     44     typedef Type*      create_t(void);
     45     typedef void       destroy_t(Type*);
     46     typedef create_t*  FPCREATE;
     47     typedef destroy_t* FPDESTORY;
     48 
     49     typedef struct _PlugInContainer {
     50         String8   sPath;
     51         HANDLE    hHandle;
     52         FPCREATE  fpCreate;
     53         FPDESTORY fpDestory;
     54         Type*     pInstance;
     55 
     56         _PlugInContainer():
     57             sPath("")
     58             ,hHandle(NULL)
     59             ,fpCreate(NULL)
     60             ,fpDestory(NULL)
     61             ,pInstance(NULL)
     62             {}
     63     } PlugInContainer;
     64 
     65     typedef KeyedVector<String8, PlugInContainer*> PlugInMap;
     66     PlugInMap m_plugInMap;
     67 
     68     typedef Vector<String8> PlugInIdList;
     69     PlugInIdList m_plugInIdList;
     70 
     71 public:
     72     /**
     73      * Load all the plug-ins in the specified directory
     74      *
     75      * @param[in] rsPlugInDirPath
     76      *     Directory path which plug-ins (dynamic library) are stored
     77      * @note Plug-ins should be implemented according to the specification
     78      */
     79     void loadPlugIns(const String8& rsPlugInDirPath) {
     80         Vector<String8> plugInFileList = getPlugInPathList(rsPlugInDirPath);
     81 
     82         if (!plugInFileList.isEmpty()) {
     83             for (unsigned int i = 0; i < plugInFileList.size(); ++i) {
     84                 loadPlugIn(plugInFileList[i]);
     85             }
     86         }
     87     }
     88 
     89     /**
     90      * Unload all the plug-ins
     91      *
     92      */
     93     void unloadPlugIns() {
     94         for (unsigned int i = 0; i < m_plugInIdList.size(); ++i) {
     95             unloadPlugIn(m_plugInIdList[i]);
     96         }
     97         m_plugInIdList.clear();
     98     }
     99 
    100     /**
    101      * Get all the IDs of available plug-ins
    102      *
    103      * @return[in] plugInIdList
    104      *     String type Vector in which all plug-in IDs are stored
    105      */
    106     Vector<String8> getPlugInIdList() const {
    107         return m_plugInIdList;
    108     }
    109 
    110     /**
    111      * Get a plug-in reference of specified ID
    112      *
    113      * @param[in] rsPlugInId
    114      *     Plug-in ID to be used
    115      * @return plugIn
    116      *     Reference of specified plug-in instance
    117      */
    118     Type& getPlugIn(const String8& rsPlugInId) {
    119         if (!contains(rsPlugInId)) {
    120             // This error case never happens
    121         }
    122         return *(m_plugInMap.valueFor(rsPlugInId)->pInstance);
    123     }
    124 
    125 public:
    126     /**
    127      * Load a plug-in stored in the specified path
    128      *
    129      * @param[in] rsPlugInPath
    130      *     Plug-in (dynamic library) file path
    131      * @note Plug-in should be implemented according to the specification
    132      */
    133     void loadPlugIn(const String8& rsPlugInPath) {
    134         if (contains(rsPlugInPath)) {
    135             return;
    136         }
    137 
    138         PlugInContainer* pPlugInContainer = new PlugInContainer();
    139 
    140         pPlugInContainer->hHandle = dlopen(rsPlugInPath.string(), RTLD_LAZY);
    141 
    142         if (NULL == pPlugInContainer->hHandle) {
    143             delete pPlugInContainer;
    144             pPlugInContainer = NULL;
    145             return;
    146         }
    147 
    148         pPlugInContainer->sPath = rsPlugInPath;
    149         pPlugInContainer->fpCreate
    150                 = (FPCREATE)dlsym(pPlugInContainer->hHandle, PLUGIN_MANAGER_CREATE);
    151         pPlugInContainer->fpDestory
    152                 = (FPDESTORY)dlsym(pPlugInContainer->hHandle, PLUGIN_MANAGER_DESTROY);
    153 
    154         if (NULL != pPlugInContainer->fpCreate && NULL != pPlugInContainer->fpDestory) {
    155             pPlugInContainer->pInstance = (Type*)pPlugInContainer->fpCreate();
    156             m_plugInIdList.add(rsPlugInPath);
    157             m_plugInMap.add(rsPlugInPath, pPlugInContainer);
    158         } else {
    159             dlclose(pPlugInContainer->hHandle);
    160             delete pPlugInContainer;
    161             pPlugInContainer = NULL;
    162             return;
    163         }
    164     }
    165 
    166     /**
    167      * Unload a plug-in stored in the specified path
    168      *
    169      * @param[in] rsPlugInPath
    170      *     Plug-in (dynamic library) file path
    171      */
    172     void unloadPlugIn(const String8& rsPlugInPath) {
    173         if (!contains(rsPlugInPath)) {
    174             return;
    175         }
    176 
    177         PlugInContainer* pPlugInContainer = m_plugInMap.valueFor(rsPlugInPath);
    178         pPlugInContainer->fpDestory(pPlugInContainer->pInstance);
    179         dlclose(pPlugInContainer->hHandle);
    180 
    181         m_plugInMap.removeItem(rsPlugInPath);
    182         delete pPlugInContainer;
    183         pPlugInContainer = NULL;
    184     }
    185 
    186 private:
    187     /**
    188      * True if TPlugInManager contains rsPlugInId
    189      */
    190     bool contains(const String8& rsPlugInId) {
    191         return m_plugInMap.indexOfKey(rsPlugInId) != NAME_NOT_FOUND;
    192     }
    193 
    194     /**
    195      * Return file path list of plug-ins stored in the specified directory
    196      *
    197      * @param[in] rsDirPath
    198      *     Directory path in which plug-ins are stored
    199      * @return plugInFileList
    200      *     String type Vector in which file path of plug-ins are stored
    201      */
    202     Vector<String8> getPlugInPathList(const String8& rsDirPath) {
    203         Vector<String8> fileList;
    204         DIR* pDir = opendir(rsDirPath.string());
    205         struct dirent* pEntry;
    206 
    207         while (NULL != pDir && NULL != (pEntry = readdir(pDir))) {
    208             if (!isPlugIn(pEntry)) {
    209                 continue;
    210             }
    211             String8 plugInPath;
    212             plugInPath += rsDirPath;
    213             plugInPath += "/";
    214             plugInPath += pEntry->d_name;
    215 
    216             fileList.add(plugInPath);
    217         }
    218 
    219         if (NULL != pDir) {
    220             closedir(pDir);
    221         }
    222 
    223         return fileList;
    224     }
    225 
    226     /**
    227      * True if the input name denotes plug-in
    228      */
    229     bool isPlugIn(const struct dirent* pEntry) const {
    230         String8 sName(pEntry->d_name);
    231         String8 extension(sName.getPathExtension());
    232         // Note that the plug-in extension must exactly match case
    233         return extension == String8(PLUGIN_EXTENSION);
    234     }
    235 
    236     /**
    237      * True if the input entry is "." or ".."
    238      */
    239     bool isDotOrDDot(const struct dirent* pEntry) const {
    240         String8 sName(pEntry->d_name);
    241         return "." == sName || ".." == sName;
    242     }
    243 
    244     /**
    245      * True if input entry is directory
    246      */
    247     bool isDirectory(const struct dirent* pEntry) const {
    248         return DT_DIR == pEntry->d_type;
    249     }
    250 
    251     /**
    252      * True if input entry is regular file
    253      */
    254     bool isRegularFile(const struct dirent* pEntry) const {
    255         return DT_REG == pEntry->d_type;
    256     }
    257 
    258     /**
    259      * True if input entry is link
    260      */
    261     bool isLink(const struct dirent* pEntry) const {
    262         return DT_LNK == pEntry->d_type;
    263     }
    264 };
    265 
    266 };
    267 
    268 #endif /* __PLUGIN_MANAGER_H__ */
    269 
    270