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
29namespace 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
43class 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
67public:
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