1 /*
2  * Copyright (C) 2017 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 #include <sys/cdefs.h>
18 #include <unistd.h>
19 
20 #include <functional>
21 
22 #include "Binder.h"
23 #include "log.h"
24 
25 __BEGIN_DECLS
26 
27 // Weak undefined references to the symbols in libbinder and libhwbinder
28 // so that libmemunreachable can call them in processes that have them
29 // loaded without requiring libmemunreachable to have dependencies on them.
30 ssize_t __attribute__((weak)) getBinderKernelReferences(size_t, uintptr_t*);
31 ssize_t __attribute__((weak)) getHWBinderKernelReferences(size_t, uintptr_t*);
32 
33 __END_DECLS
34 
35 namespace android {
36 
37 static bool BinderReferencesToVector(allocator::vector<uintptr_t>& refs,
38                                      std::function<ssize_t(size_t, uintptr_t*)> fn) {
39   if (fn == nullptr) {
40     return true;
41   }
42 
43   size_t size = refs.size();
44 
45   do {
46     refs.resize(size);
47 
48     ssize_t ret = fn(refs.size(), refs.data());
49     if (ret < 0) {
50       return false;
51     }
52 
53     size = ret;
54   } while (size > refs.size());
55 
56   refs.resize(size);
57   return true;
58 }
59 
60 bool BinderReferences(allocator::vector<uintptr_t>& refs) {
61   refs.clear();
62 
63   allocator::vector<uintptr_t> binder_refs{refs.get_allocator()};
64   if (BinderReferencesToVector(refs, getBinderKernelReferences)) {
65     refs.insert(refs.end(), binder_refs.begin(), binder_refs.end());
66   } else {
67     MEM_ALOGE("getBinderKernelReferences failed");
68   }
69 
70   allocator::vector<uintptr_t> hwbinder_refs{refs.get_allocator()};
71   if (BinderReferencesToVector(hwbinder_refs, getHWBinderKernelReferences)) {
72     refs.insert(refs.end(), hwbinder_refs.begin(), hwbinder_refs.end());
73   } else {
74     MEM_ALOGE("getHWBinderKernelReferences failed");
75   }
76 
77   return true;
78 }
79 
80 }  // namespace android
81