1 /*
2 * Copyright (C) 2024 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 "binary_loader.h"
18
19 // If dlopen is unnecessary (eg. for shared libs), absoluteBinPath should be empty.
BinaryLoader(const std::string absoluteBinPath)20 BinaryLoader::BinaryLoader(const std::string absoluteBinPath) {
21 if (!absoluteBinPath.empty()) {
22 binPath = absoluteBinPath.c_str();
23 binHandle = dlopen(binPath, RTLD_NOW);
24 if (!binHandle) {
25 printf("Error opening binary: %s. Error: %s\n", binPath, dlerror());
26 }
27 }
28 }
29
~BinaryLoader()30 BinaryLoader::~BinaryLoader() {
31 if (binHandle) {
32 dlclose(binHandle);
33 binHandle = nullptr;
34 }
35 binPath = nullptr;
36 baseAddress = 0;
37 }
38
39 // When functionOffset is 0, return the base address
getFunctionAddress(uintptr_t functionOffset)40 uintptr_t BinaryLoader::getFunctionAddress(uintptr_t functionOffset) {
41 if (!baseAddress) {
42 if (!dl_iterate_phdr(callback, (void*)this) || !baseAddress) {
43 return 0;
44 }
45 }
46 return baseAddress + functionOffset;
47 }
48
49 // Callback function to iterate loaded binaries
callback(struct dl_phdr_info * info,size_t,void * data)50 int BinaryLoader::callback(struct dl_phdr_info* info, size_t /* size */, void* data) {
51 BinaryLoader* binLoader = (BinaryLoader*)data;
52
53 // Check if the library name matches the binPath and p_type is PT_LOAD
54 if (strcmp(info->dlpi_name, binLoader->binPath) == 0) {
55 for (size_t j = 0; j < info->dlpi_phnum; ++j) {
56 if (info->dlpi_phdr[j].p_type == PT_LOAD) {
57 binLoader->baseAddress = (uintptr_t)(info->dlpi_addr + info->dlpi_phdr[j].p_vaddr);
58 return 1;
59 }
60 }
61 }
62 return 0;
63 }
64