Home | History | Annotate | Download | only in binder 
      1 /*
      2  * Copyright (C) 2009 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 BINDER_PERMISSION_H
     18 #define BINDER_PERMISSION_H
     19 
     20 #ifndef __ANDROID_VNDK__
     21 
     22 #include <stdint.h>
     23 #include <unistd.h>
     24 
     25 #include <utils/String16.h>
     26 #include <utils/Singleton.h>
     27 #include <utils/SortedVector.h>
     28 
     29 namespace android {
     30 // ---------------------------------------------------------------------------
     31 
     32 /*
     33  * PermissionCache caches permission checks for a given uid.
     34  *
     35  * Currently the cache is not updated when there is a permission change,
     36  * for instance when an application is uninstalled.
     37  *
     38  * IMPORTANT: for the reason stated above, only system permissions are safe
     39  * to cache. This restriction may be lifted at a later time.
     40  *
     41  */
     42 
     43 class PermissionCache : Singleton<PermissionCache> {
     44     struct Entry {
     45         String16    name;
     46         uid_t       uid;
     47         bool        granted;
     48         inline bool operator < (const Entry& e) const {
     49             return (uid == e.uid) ? (name < e.name) : (uid < e.uid);
     50         }
     51     };
     52     mutable Mutex mLock;
     53     // we pool all the permission names we see, as many permissions checks
     54     // will have identical names
     55     SortedVector< String16 > mPermissionNamesPool;
     56     // this is our cache per say. it stores pooled names.
     57     SortedVector< Entry > mCache;
     58 
     59     // free the whole cache, but keep the permission name pool
     60     void purge();
     61 
     62     status_t check(bool* granted,
     63             const String16& permission, uid_t uid) const;
     64 
     65     void cache(const String16& permission, uid_t uid, bool granted);
     66 
     67 public:
     68     PermissionCache();
     69 
     70     static bool checkCallingPermission(const String16& permission);
     71 
     72     static bool checkCallingPermission(const String16& permission,
     73                                 int32_t* outPid, int32_t* outUid);
     74 
     75     static bool checkPermission(const String16& permission,
     76             pid_t pid, uid_t uid);
     77 };
     78 
     79 // ---------------------------------------------------------------------------
     80 }; // namespace android
     81 
     82 #else // __ANDROID_VNDK__
     83 #error "This header is not visible to vendors"
     84 #endif // __ANDROID_VNDK__
     85 
     86 #endif /* BINDER_PERMISSION_H */
     87