1 /*
2 * Copyright (C) 2005 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 #define LOG_TAG "misc"
18
19 #include <utils/misc.h>
20
21 #include <pthread.h>
22
23 #include <utils/Log.h>
24 #include <utils/Vector.h>
25
26 #if defined(__ANDROID__)
27 #include <dlfcn.h>
28 #include <vndksupport/linker.h>
29 #endif
30
31 extern "C" void do_report_sysprop_change();
32
33 using namespace android;
34
35 namespace android {
36
37 struct sysprop_change_callback_info {
38 sysprop_change_callback callback;
39 int priority;
40 };
41
42 #if !defined(_WIN32)
43 static pthread_mutex_t gSyspropMutex = PTHREAD_MUTEX_INITIALIZER;
44 static Vector<sysprop_change_callback_info>* gSyspropList = NULL;
45 #endif
46
add_sysprop_change_callback(sysprop_change_callback cb,int priority)47 void add_sysprop_change_callback(sysprop_change_callback cb, int priority) {
48 #if !defined(_WIN32)
49 pthread_mutex_lock(&gSyspropMutex);
50 if (gSyspropList == NULL) {
51 gSyspropList = new Vector<sysprop_change_callback_info>();
52 }
53 sysprop_change_callback_info info;
54 info.callback = cb;
55 info.priority = priority;
56 bool added = false;
57 for (size_t i=0; i<gSyspropList->size(); i++) {
58 if (priority >= gSyspropList->itemAt(i).priority) {
59 gSyspropList->insertAt(info, i);
60 added = true;
61 break;
62 }
63 }
64 if (!added) {
65 gSyspropList->add(info);
66 }
67 pthread_mutex_unlock(&gSyspropMutex);
68 #endif
69 }
70
71 #if defined(__ANDROID__)
get_report_sysprop_change_func()72 void (*get_report_sysprop_change_func())() {
73 void (*func)() = nullptr;
74 void* handle = android_load_sphal_library("libutils.so", RTLD_NOW);
75 if (handle != nullptr) {
76 func = reinterpret_cast<decltype(func)>(dlsym(handle, "do_report_sysprop_change"));
77 }
78
79 return func;
80 }
81 #endif
82
report_sysprop_change()83 void report_sysprop_change() {
84 do_report_sysprop_change();
85
86 #if defined(__ANDROID__)
87 // libutils.so is double loaded; from the default namespace and from the
88 // 'sphal' namespace. Redirect the sysprop change event to the other instance
89 // of libutils.so loaded in the 'sphal' namespace so that listeners attached
90 // to that instance is also notified with this event.
91 static auto func = get_report_sysprop_change_func();
92 if (func != nullptr) {
93 (*func)();
94 }
95 #endif
96 }
97
98 }; // namespace android
99
do_report_sysprop_change()100 void do_report_sysprop_change() {
101 #if !defined(_WIN32)
102 pthread_mutex_lock(&gSyspropMutex);
103 Vector<sysprop_change_callback_info> listeners;
104 if (gSyspropList != NULL) {
105 listeners = *gSyspropList;
106 }
107 pthread_mutex_unlock(&gSyspropMutex);
108
109 //ALOGI("Reporting sysprop change to %d listeners", listeners.size());
110 for (size_t i=0; i<listeners.size(); i++) {
111 listeners[i].callback();
112 }
113 #endif
114 }
115