├── .gitignore
├── .idea
├── .gitignore
├── compiler.xml
├── gradle.xml
└── misc.xml
├── README.md
├── app
├── .gitignore
├── build.gradle
├── proguard-rules.pro
└── src
│ ├── androidTest
│ └── java
│ │ └── com
│ │ └── luoye
│ │ └── localdlfcn
│ │ └── ExampleInstrumentedTest.java
│ ├── main
│ ├── AndroidManifest.xml
│ ├── cpp
│ │ ├── CMakeLists.txt
│ │ ├── dlfcn
│ │ │ ├── local_dlfcn.c
│ │ │ └── local_dlfcn.h
│ │ ├── logger.h
│ │ └── native-lib.cpp
│ ├── java
│ │ └── com
│ │ │ └── luoye
│ │ │ └── localdlfcn
│ │ │ └── MainActivity.java
│ └── res
│ │ ├── drawable-v24
│ │ └── ic_launcher_foreground.xml
│ │ ├── drawable
│ │ └── ic_launcher_background.xml
│ │ ├── layout
│ │ └── activity_main.xml
│ │ ├── mipmap-anydpi-v26
│ │ ├── ic_launcher.xml
│ │ └── ic_launcher_round.xml
│ │ ├── mipmap-hdpi
│ │ ├── ic_launcher.webp
│ │ └── ic_launcher_round.webp
│ │ ├── mipmap-mdpi
│ │ ├── ic_launcher.webp
│ │ └── ic_launcher_round.webp
│ │ ├── mipmap-xhdpi
│ │ ├── ic_launcher.webp
│ │ └── ic_launcher_round.webp
│ │ ├── mipmap-xxhdpi
│ │ ├── ic_launcher.webp
│ │ └── ic_launcher_round.webp
│ │ ├── mipmap-xxxhdpi
│ │ ├── ic_launcher.webp
│ │ └── ic_launcher_round.webp
│ │ ├── values-night
│ │ └── themes.xml
│ │ └── values
│ │ ├── colors.xml
│ │ ├── strings.xml
│ │ └── themes.xml
│ └── test
│ └── java
│ └── com
│ └── luoye
│ └── localdlfcn
│ └── ExampleUnitTest.java
├── build.gradle
├── gradle.properties
├── gradle
└── wrapper
│ ├── gradle-wrapper.jar
│ └── gradle-wrapper.properties
├── gradlew
├── gradlew.bat
└── settings.gradle
/.gitignore:
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1 | *.iml
2 | .gradle
3 | /local.properties
4 | /.idea/caches
5 | /.idea/libraries
6 | /.idea/modules.xml
7 | /.idea/workspace.xml
8 | /.idea/navEditor.xml
9 | /.idea/assetWizardSettings.xml
10 | .DS_Store
11 | /build
12 | /captures
13 | .externalNativeBuild
14 | .cxx
15 | local.properties
16 |
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/.idea/.gitignore:
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1 | # Default ignored files
2 | /shelf/
3 | /workspace.xml
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/.idea/misc.xml:
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/README.md:
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1 | # local_dlfcn
2 |
3 | 读取本地so文件的符号的偏移
4 |
5 | ## 用法
6 |
7 | ```cpp
8 | #ifdef __LP64__
9 | const char *lib_path = "/system/lib64/libc.so";
10 | #else
11 | const char *lib_path = "/system/lib/libc.so";
12 | #endif
13 |
14 | const char *sym_name = "open";
15 |
16 | struct local_dlfcn_handle *handle = static_cast(local_dlopen(lib_path));
17 | off_t offset = local_dlsym(handle,sym_name);
18 | local_dlclose(handle);
19 | ```
20 |
21 | ## 感谢
22 |
23 | - [Nougat_dlfunctions](https://github.com/avs333/Nougat_dlfunctions)
24 | - [dlfcn_compat](https://github.com/lizhangqu/dlfcn_compat)
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/app/.gitignore:
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1 | /build
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/app/build.gradle:
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1 | plugins {
2 | id 'com.android.application'
3 | }
4 |
5 | android {
6 | compileSdk 33
7 |
8 | defaultConfig {
9 | applicationId "com.luoye.localdlfcn"
10 | minSdk 21
11 | targetSdk 33
12 | versionCode 1
13 | versionName "1.0"
14 |
15 | testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
16 | externalNativeBuild {
17 | cmake {
18 | cppFlags ''
19 | }
20 | }
21 | }
22 |
23 | buildTypes {
24 | release {
25 | minifyEnabled false
26 | proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
27 | }
28 | }
29 | compileOptions {
30 | sourceCompatibility JavaVersion.VERSION_1_8
31 | targetCompatibility JavaVersion.VERSION_1_8
32 | }
33 | externalNativeBuild {
34 | cmake {
35 | path file('src/main/cpp/CMakeLists.txt')
36 | version '3.18.1'
37 | }
38 | }
39 | buildFeatures {
40 | viewBinding true
41 | }
42 | }
43 |
44 | dependencies {
45 |
46 | implementation 'androidx.appcompat:appcompat:1.3.0'
47 | implementation 'com.google.android.material:material:1.4.0'
48 | implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
49 | testImplementation 'junit:junit:4.13.2'
50 | androidTestImplementation 'androidx.test.ext:junit:1.1.3'
51 | androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
52 | }
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/app/proguard-rules.pro:
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1 | # Add project specific ProGuard rules here.
2 | # You can control the set of applied configuration files using the
3 | # proguardFiles setting in build.gradle.
4 | #
5 | # For more details, see
6 | # http://developer.android.com/guide/developing/tools/proguard.html
7 |
8 | # If your project uses WebView with JS, uncomment the following
9 | # and specify the fully qualified class name to the JavaScript interface
10 | # class:
11 | #-keepclassmembers class fqcn.of.javascript.interface.for.webview {
12 | # public *;
13 | #}
14 |
15 | # Uncomment this to preserve the line number information for
16 | # debugging stack traces.
17 | #-keepattributes SourceFile,LineNumberTable
18 |
19 | # If you keep the line number information, uncomment this to
20 | # hide the original source file name.
21 | #-renamesourcefileattribute SourceFile
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/app/src/androidTest/java/com/luoye/localdlfcn/ExampleInstrumentedTest.java:
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1 | package com.luoye.localdlfcn;
2 |
3 | import android.content.Context;
4 |
5 | import androidx.test.platform.app.InstrumentationRegistry;
6 | import androidx.test.ext.junit.runners.AndroidJUnit4;
7 |
8 | import org.junit.Test;
9 | import org.junit.runner.RunWith;
10 |
11 | import static org.junit.Assert.*;
12 |
13 | /**
14 | * Instrumented test, which will execute on an Android device.
15 | *
16 | * @see Testing documentation
17 | */
18 | @RunWith(AndroidJUnit4.class)
19 | public class ExampleInstrumentedTest {
20 | @Test
21 | public void useAppContext() {
22 | // Context of the app under test.
23 | Context appContext = InstrumentationRegistry.getInstrumentation().getTargetContext();
24 | assertEquals("com.luoye.localdlfcn", appContext.getPackageName());
25 | }
26 | }
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/app/src/main/AndroidManifest.xml:
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5 |
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17 |
18 |
19 |
20 |
21 |
22 |
23 |
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/app/src/main/cpp/CMakeLists.txt:
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1 | # For more information about using CMake with Android Studio, read the
2 | # documentation: https://d.android.com/studio/projects/add-native-code.html
3 |
4 | # Sets the minimum version of CMake required to build the native library.
5 |
6 | cmake_minimum_required(VERSION 3.18.1)
7 |
8 | # Declares and names the project.
9 |
10 | project("localdlfcn")
11 |
12 | # Creates and names a library, sets it as either STATIC
13 | # or SHARED, and provides the relative paths to its source code.
14 | # You can define multiple libraries, and CMake builds them for you.
15 | # Gradle automatically packages shared libraries with your APK.
16 |
17 | add_library( # Sets the name of the library.
18 | localdlfcn
19 |
20 | # Sets the library as a shared library.
21 | SHARED
22 |
23 | # Provides a relative path to your source file(s).
24 | dlfcn/local_dlfcn.c
25 | native-lib.cpp)
26 |
27 | # Searches for a specified prebuilt library and stores the path as a
28 | # variable. Because CMake includes system libraries in the search path by
29 | # default, you only need to specify the name of the public NDK library
30 | # you want to add. CMake verifies that the library exists before
31 | # completing its build.
32 |
33 | find_library( # Sets the name of the path variable.
34 | log-lib
35 |
36 | # Specifies the name of the NDK library that
37 | # you want CMake to locate.
38 | log)
39 |
40 | # Specifies libraries CMake should link to your target library. You
41 | # can link multiple libraries, such as libraries you define in this
42 | # build script, prebuilt third-party libraries, or system libraries.
43 |
44 | target_link_libraries( # Specifies the target library.
45 | localdlfcn
46 |
47 | # Links the target library to the log library
48 | # included in the NDK.
49 | ${log-lib})
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/app/src/main/cpp/dlfcn/local_dlfcn.c:
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1 | //
2 | // Created by luoyesiqiu
3 | //
4 |
5 | #include "local_dlfcn.h"
6 | #ifdef __LP64__
7 | #define Elf_Ehdr Elf64_Ehdr
8 | #define Elf_Shdr Elf64_Shdr
9 | #define Elf_Sym Elf64_Sym
10 | #else
11 | #define Elf_Ehdr Elf32_Ehdr
12 | #define Elf_Shdr Elf32_Shdr
13 | #define Elf_Sym Elf32_Sym
14 | #endif
15 |
16 | /**
17 | * 打开一个本地so文件
18 | * @param lib_path so文件路径
19 | * @return 句柄
20 | */
21 | void *local_dlopen(const char* lib_path){
22 | int fd = open(lib_path, O_RDONLY);
23 | if (fd < 0) {
24 | return NULL;
25 | }
26 |
27 | size_t size = lseek(fd, 0, SEEK_END);
28 | if (size <= 0) {
29 | return NULL;
30 | }
31 |
32 | Elf_Ehdr *elf = (Elf_Ehdr *) mmap(0, size, PROT_READ, MAP_PRIVATE, fd, 0);
33 | close(fd);
34 | fd = -1;
35 |
36 | if (elf == MAP_FAILED) {
37 | return NULL;
38 | }
39 |
40 | char* shoff = ((char *) elf) + elf->e_shoff;
41 | struct local_dlfcn_handle* handle = (struct local_dlfcn_handle *) calloc(1,sizeof(struct local_dlfcn_handle));
42 | handle->elf = (char *)elf;
43 | handle->size = size;
44 | for (int k = 0; k < elf->e_shnum; k++, shoff += elf->e_shentsize) {
45 | Elf_Shdr *sh = (Elf_Shdr *) shoff;
46 | LOGD("%s: k=%d shdr=%p type=%x", __func__, k, sh, sh->sh_type);
47 |
48 | switch (sh->sh_type) {
49 | case SHT_DYNSYM:
50 | if (handle->dynsym){
51 | goto tail;
52 | }
53 | handle->dynsym = malloc(sh->sh_size);
54 | if (!handle->dynsym) {
55 | goto tail;
56 | }
57 | memcpy(handle->dynsym, ((char *) elf) + sh->sh_offset, sh->sh_size);
58 | handle->nsyms = (sh->sh_size / sizeof(Elf_Sym));
59 | LOGD("%s SHT_DYNSYM,shndx",__func__);
60 | break;
61 |
62 | case SHT_STRTAB:
63 | if (handle->dynstr) break; /* .dynstr is guaranteed to be the first STRTAB */
64 | handle->dynstr = malloc(sh->sh_size);
65 | if (!handle->dynstr) {
66 | goto tail;
67 | }
68 | memcpy(handle->dynstr, ((char *) elf) + sh->sh_offset, sh->sh_size);
69 | LOGD("%s SHT_STRTAB",__func__);
70 | break;
71 | }
72 |
73 | }
74 | return handle;
75 |
76 | tail:
77 | if (fd >= 0) close(fd);
78 | if (elf != MAP_FAILED) {
79 | munmap(elf, size);
80 | }
81 | local_dlclose(handle);
82 | return NULL;
83 | }
84 |
85 | /**
86 | * 从so文件查找一个符号
87 | * @param handle 句柄
88 | * @param sym_name 符号名
89 | * @return 符号在so文件中的偏移
90 | */
91 | off_t local_dlsym(void *handle,const char *sym_name){
92 | struct local_dlfcn_handle* h = (struct local_dlfcn_handle*)handle;
93 | Elf_Sym *sym = (Elf_Sym *) h->dynsym;
94 | char *strings = h->dynstr;
95 | int dynsym_sh_ndx = 0;
96 | off_t dynsym_st_value = 0;
97 | int found_sym = 0;
98 | for(int i = 0; i < h->nsyms;sym++,i++){
99 | if (strcmp(strings + sym->st_name, sym_name) == 0) {
100 | dynsym_st_value = sym->st_value;
101 | dynsym_sh_ndx = sym->st_shndx;
102 | found_sym = 1;
103 | LOGD("%s %s found at %p,st_shndx = %ld",__func__, sym_name, dynsym_st_value,sym->st_shndx);
104 | }
105 | }
106 | if(!found_sym){
107 | return -1;
108 | }
109 | Elf_Ehdr *elf = (Elf_Ehdr *)h->elf;
110 | char* shoff = ((char *) elf) + elf->e_shoff;
111 | for(int i = 0;elf->e_shnum;i++,shoff += elf->e_shentsize){
112 | if(dynsym_sh_ndx == i){
113 | Elf_Shdr *sh = (Elf_Shdr *) shoff;
114 | return sh->sh_offset + dynsym_st_value - sh->sh_addr;
115 | }
116 | }
117 | return -1;
118 | }
119 |
120 | /**
121 | * 关闭句柄
122 | * @param handle 句柄
123 | */
124 | void local_dlclose(void *handle){
125 | if(handle){
126 | struct local_dlfcn_handle *h = (struct local_dlfcn_handle *) handle;
127 | if(h->dynstr) free(h->dynstr);
128 | if(h->dynsym) free(h->dynsym);
129 | if (h->elf != MAP_FAILED) {
130 | munmap(h->elf, h->size);
131 | }
132 | free(handle);
133 | }
134 | }
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/app/src/main/cpp/dlfcn/local_dlfcn.h:
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1 | //
2 | // Created by luoyesiqiu
3 | //
4 |
5 | #ifndef LOCAL_DLFCN_H
6 | #define LOCAL_DLFCN_H
7 |
8 | #include
9 | #include
10 | #include
11 | #include
12 | #include
13 | #include
14 | #include
15 | #include "../logger.h"
16 |
17 | #ifdef __cplusplus
18 | extern "C" {
19 | #endif
20 |
21 | struct local_dlfcn_handle{
22 | char *elf;
23 | size_t size;
24 | char *dynsym;
25 | int nsyms;
26 | char *dynstr;
27 | };
28 |
29 | void *local_dlopen(const char *lib_path);
30 | off_t local_dlsym(void *handle, const char *sym_name);
31 | void local_dlclose(void *handle);
32 |
33 | #ifdef __cplusplus
34 | }
35 | #endif
36 |
37 | #endif
38 |
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/app/src/main/cpp/logger.h:
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1 | //
2 | // Created by luoyesiqiu
3 | //
4 |
5 | #ifndef LOCAL_DLFCN_LOGGER_H
6 | #define LOCAL_DLFCN_LOGGER_H
7 |
8 | #include
9 |
10 | #define TAG "local_dlfcn"
11 |
12 | #define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG, TAG, __VA_ARGS__)
13 |
14 | #endif //LOCAL_DLFCN_LOGGER_H
15 |
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/app/src/main/cpp/native-lib.cpp:
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1 | #include
2 | #include
3 | #include
4 | #include "dlfcn/local_dlfcn.h"
5 |
6 | extern "C" JNIEXPORT jstring JNICALL
7 | Java_com_luoye_localdlfcn_MainActivity_test(
8 | JNIEnv* env,
9 | jobject /* this */) {
10 |
11 | #ifdef __LP64__
12 | const char *lib_path = "/system/lib64/libc.so";
13 | #else
14 | const char *lib_path = "/system/lib/libc.so";
15 | #endif
16 | #define CMP_COUNT 8
17 | const char *sym_name = "open";
18 |
19 | struct local_dlfcn_handle *handle = static_cast(local_dlopen(lib_path));
20 |
21 | off_t offset = local_dlsym(handle,sym_name);
22 |
23 | FILE *fp = fopen(lib_path,"rb");
24 | char file_bytes[CMP_COUNT] = {0};
25 | if(fp != NULL){
26 | fseek(fp,offset,SEEK_SET);
27 | fread(file_bytes,1,CMP_COUNT,fp);
28 | fclose(fp);
29 | }
30 |
31 | void *dl_handle = dlopen(lib_path,RTLD_NOW);
32 | void *sym = dlsym(dl_handle,sym_name);
33 |
34 | int is_hook = memcmp(file_bytes,sym,CMP_COUNT) != 0;
35 |
36 | local_dlclose(handle);
37 | dlclose(dl_handle);
38 |
39 | char text[128] = {0};
40 | snprintf(text,128,"Function \"%s\" is hook: %s",sym_name,is_hook ? "true" : "false");
41 |
42 | return env->NewStringUTF(text);
43 | }
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/app/src/main/java/com/luoye/localdlfcn/MainActivity.java:
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1 | package com.luoye.localdlfcn;
2 |
3 | import androidx.appcompat.app.AppCompatActivity;
4 |
5 | import android.os.Bundle;
6 | import android.widget.TextView;
7 |
8 | import com.luoye.localdlfcn.databinding.ActivityMainBinding;
9 |
10 | public class MainActivity extends AppCompatActivity {
11 |
12 | // Used to load the 'localdlfcn' library on application startup.
13 | static {
14 | System.loadLibrary("localdlfcn");
15 | }
16 |
17 | private ActivityMainBinding binding;
18 |
19 | @Override
20 | protected void onCreate(Bundle savedInstanceState) {
21 | super.onCreate(savedInstanceState);
22 |
23 | binding = ActivityMainBinding.inflate(getLayoutInflater());
24 | setContentView(binding.getRoot());
25 |
26 | // Example of a call to a native method
27 | TextView tv = binding.sampleText;
28 | tv.setText(test());
29 | }
30 |
31 | /**
32 | * A native method that is implemented by the 'localdlfcn' native library,
33 | * which is packaged with this application.
34 | */
35 | public native String test();
36 | }
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/app/src/main/res/drawable-v24/ic_launcher_foreground.xml:
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