Refactor & Cleanup

Author: pinwhell

.gitignore

@@ -7,3 +7,4 @@ src/obj/local/armeabi-v7a/mem
 src/obj/local/arm64-v8a/mem
 src/libs/armeabi-v7a/mem
 src/libs/arm64-v8a/mem
+.vscode/settings.json

src/BI.bat

@@ -0,0 +1 @@
+Build.bat & Update.bat & pause & cls

src/Build.bat

@@ -0,0 +1 @@
+ndk-build clean & ndk-build -j4 -B

src/MBI.bat

@@ -0,0 +1 @@
+ndk-build & Update.bat & pause & cls

src/Update.bat

@@ -0,0 +1,7 @@
+set moduleName=mem
+
+HD-Adb -s emulator-5554 shell "su -c 'rm data/local/tmp/%moduleName%'"
+HD-Adb -s emulator-5554 push libs/armeabi-v7a/%moduleName% data/local/tmp/%moduleName%
+HD-Adb -s emulator-5554 shell "su -c 'chmod 7777 data/local/tmp/%moduleName%'"
+HD-Adb -s emulator-5554 shell "su -c 'chown 0 data/local/tmp/%moduleName%'"
+HD-Adb -s emulator-5554 shell "su -c 'chgrp 0 data/local/tmp/%moduleName%'"

src/jni/Android.mk

@@ -4,6 +4,6 @@ LOCAL_ARM_MODE := arm
 LOCAL_LDLIBS := -llog
 LOCAL_ARM_NEON := false
 LOCAL_MODULE := mem
-LOCAL_SRC_FILES := main.cpp ProcessManager.cpp
-LOCAL_CFLAGS :=
+LOCAL_SRC_FILES := main.cpp ProcessManager.cpp ElfUtils.cpp
+LOCAL_CFLAGS := -fexceptions
 include $(BUILD_EXECUTABLE)

src/jni/ElfUtils.cpp

@@ -0,0 +1,141 @@
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include "ElfUtils.h"
+#include <fcntl.h>
+#include <unistd.h>
+
+bool ElfOpen(const std::string& fullModulePath, std::function<void(ElfPack libMap)> callback)
+{
+    int libFd = open(fullModulePath.c_str(), O_RDONLY);
+
+    if(libFd < 0)
+        return false;
+
+    struct stat libStats;
+
+    if(fstat(libFd, &libStats) != 0)
+    {
+        close(libFd);
+        return false;
+    } 
+
+    ElfPack libMap;
+    
+    libMap.baseV = mmap(NULL, libStats.st_size, PROT_READ, MAP_SHARED, libFd, 0 );
+
+    if(libMap.res == -1)
+    {
+        close(libFd);
+        return false;
+    }   
+
+    callback(libMap);
+
+    munmap(libMap.baseV, libStats.st_size);
+
+    close(libFd);
+    return true;
+}
+
+Elf32_Shdr* ElfSectionByIndex(ElfPack libMap, unsigned int sectionIdx)
+{
+    if((sectionIdx < libMap.header->e_shnum) == false)
+        return nullptr;
+
+    Elf32_Shdr* libElfSections = (Elf32_Shdr*)(libMap.base + libMap.header->e_shoff);
+
+    return libElfSections + sectionIdx;
+}
+
+void ElfForEachSection(ElfPack libMap, std::function<bool(Elf32_Shdr* pCurrentSection)> callback)
+{
+    Elf32_Shdr* libElfSections = (Elf32_Shdr*)(libMap.base + libMap.header->e_shoff);
+
+    for(int i = 0; i < libMap.header->e_shnum; i++)
+    {
+        if(callback(libElfSections + i) == false)
+            break;
+    }
+}
+
+Elf32_Shdr* ElfLookupSection(ElfPack libMap, uint32_t sectionType)
+{
+    Elf32_Shdr* secHeader = nullptr;
+
+    ElfForEachSection(libMap, [&](Elf32_Shdr* currSection){
+        if(currSection->sh_type != sectionType)
+            return true;
+        
+        secHeader = currSection;
+
+        return false;        
+    });
+
+    return secHeader;
+}
+
+Elf32_Shdr* ElfGetSymbolSection(ElfPack libMap)
+{
+    Elf32_Shdr* result = nullptr;
+    
+    result = ElfLookupSection(libMap, SHT_SYMTAB);
+
+    if(result)
+        return result;
+
+    result = ElfLookupSection(libMap, SHT_DYNSYM);
+
+    if(result)
+        return result;
+
+    return result;
+}
+
+bool ElfForEachSymbol(ElfPack libMap, std::function<bool(Elf32_Sym* pCurrentSym, const char* pCurrSymName)> callback)
+{
+    Elf32_Shdr* symTable = ElfGetSymbolSection(libMap);
+
+    if(symTable == nullptr)
+        return false;
+
+    Elf32_Shdr* strTable = ElfSectionByIndex(libMap, symTable->sh_link);
+
+    if(strTable == nullptr)
+        return false;
+
+    const char* elfStrBlob = (const char*)(libMap.base + strTable->sh_offset);
+
+    int nSyms = symTable->sh_size / sizeof(Elf32_Sym);
+    Elf32_Sym* symEntry = (Elf32_Sym*)(libMap.base + symTable->sh_offset);
+    Elf32_Sym* symEnd = symEntry + nSyms;
+
+    for(Elf32_Sym* sym = symEntry; sym < symEnd;  sym++)
+    {
+        if((ELF32_ST_BIND(sym->st_info) & (STT_FUNC | STB_GLOBAL)) == 0)
+            continue;
+
+        if(callback(sym, elfStrBlob + sym->st_name) == false)
+            break;
+    }
+
+    return true;
+}
+
+bool ElfLookupSymbol(ElfPack libMap, const std::string& symbolName, uint64_t* outSymbolOff)
+{
+    Elf32_Sym* result = nullptr;
+    if(ElfForEachSymbol(libMap, [&](Elf32_Sym* currSym, const char* currSymName){
+        if(strcmp(currSymName, symbolName.c_str()))
+            return true;
+
+        result = currSym;
+
+        return false;
+    }) == false)
+        return false;
+
+    if(outSymbolOff && result)
+        *outSymbolOff = result->st_value;
+
+    return result != nullptr;
+}

src/jni/ElfUtils.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include <functional>
+#include <elf.h>
+#include <string>
+
+union ElfPack {
+    Elf32_Ehdr* header;
+    uintptr_t base;
+    void* baseV;
+    int res;
+};
+
+bool ElfOpen(const std::string& fullModulePath, std::function<void(ElfPack libMap)> callback);
+Elf32_Shdr* ElfSectionByIndex(ElfPack libMap, unsigned int sectionIdx);
+void ElfForEachSection(ElfPack libMap, std::function<bool(Elf32_Shdr* pCurrentSection)> callback);
+Elf32_Shdr* ElfLookupSection(ElfPack libMap, uint32_t sectionType);
+Elf32_Shdr* ElfGetSymbolSection(ElfPack libMap);
+bool ElfForEachSymbol(ElfPack libMap, std::function<bool(Elf32_Sym* pCurrentSym, const char* pCurrSymName)> callback);
+bool ElfLookupSymbol(ElfPack libMap, const std::string& symbolName, uint64_t* outSymbolOff = nullptr);