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// Copyright 2021 The Mumble Developers. All rights reserved.
// Use of this source code is governed by a BSD-style license
// that can be found in the LICENSE file at the root of the
// Mumble source tree or at <https://www.mumble.info/LICENSE>.
// This is the main header for process/OS stuff; it's included in most plugins
// because values can rarely be retrieved without accessing the process' memory.
//
// Various functions are provided for common tasks when reading from memory.
// The most important are getModuleAddr() and peekProc(); the first returns the
// base address of a module (e.g. shared library), the latter reads memory at the
// specified address and stores it in a variable.
#ifndef MUMBLE_POSITIONAL_AUDIO_MAIN_H_
#define MUMBLE_POSITIONAL_AUDIO_MAIN_H_
#if !defined(OS_WINDOWS) && !defined(OS_LINUX)
# error "Please define either OS_WINDOWS or OS_LINUX"
#endif
#include "mumble_positional_audio_win32_internals.h"
#include <chrono>
#include <cstring>
#include <vector>
#ifdef OS_WINDOWS
static const bool isWin32 = true;
#else
static bool isWin32;
#endif
static bool is64Bit;
static procid_t pPid;
static procptr_t pModule;
#define GET_POINTER_SIZE (is64Bit ? 8 : 4)
static inline bool peekProc(const procptr_t &addr, void *dest, const size_t &len);
static inline procptr_t getModuleAddr(const procid_t &pid, const wchar_t *modname);
static inline procptr_t getModuleAddr(const wchar_t *modname) {
return getModuleAddr(pPid, modname);
}
template< class T > static inline bool peekProc(const procptr_t &addr, T &dest) {
return peekProc(addr, &dest, sizeof(T));
}
template< class T > static inline T peekProc(const procptr_t &addr) {
T ret;
if (!peekProc(addr, &ret, sizeof(T))) {
memset(&ret, 0, sizeof(ret));
}
return ret;
}
template< typename T > static inline std::vector< T > peekProcVector(const procptr_t addr, const size_t elements) {
try {
std::vector< T > var(elements);
peekProc(addr, &var[0], sizeof(T) * elements);
return var;
} catch (std::bad_alloc &) {
return std::vector< T >();
}
}
/// This function is very useful when there is an array of structures and we only need to store a part of each.
/// The Source Engine plugin needs it because there is a structure that happens to be larger in the Linux version of
/// Left 4 Dead 2. Since the extra members are unknown, we simply discard the extra bytes when reading the array of
/// structures.
template< typename T >
static inline std::vector< T > peekProcVector(const procptr_t addr, const size_t elements,
const size_t realStructSize) {
if (realStructSize == sizeof(T)) {
// If the structure's size is correct, there is no need for this special function.
return peekProcVector< T >(addr, elements);
} else if (realStructSize < sizeof(T)) {
return std::vector< T >();
}
// Read the full structures into a vector.
const std::vector< uint8_t > fullStructs = peekProcVector< uint8_t >(addr, realStructSize * elements);
// Allocate vector for the known structures.
std::vector< T > ret(elements);
// Copy elements from the vector containing the full structures, discarding extra bytes.
const uint8_t *seek = &fullStructs[0];
for (size_t i = 0; i < elements; ++i, seek += realStructSize) {
memcpy(&ret[i], seek, sizeof(T));
}
return ret;
}
/// Reads the specified amount of data at the specified address and returns it as std::string.
/// An empty std::string is returned in case of error.
///
/// If \p length is 0, the function reads one byte at a time and stops when either '\0' is found or 3 seconds have
/// passed. The successfully read data is returned, also in case of error.
static inline std::string peekProcString(const procptr_t addr, const size_t length = 0) {
std::string string;
if (length > 0) {
string.resize(length);
if (!peekProc(addr, &string[0], length)) {
return std::string();
}
} else {
auto now = std::chrono::steady_clock::now();
const auto end = now + std::chrono::seconds(3);
for (procptr_t i = 0; now < end; ++i) {
char ch = 0;
if (!peekProc(addr + i, &ch, sizeof(ch)) || ch == '\0') {
break;
}
string += ch;
// Update current time.
now = std::chrono::steady_clock::now();
}
}
return string;
}
static inline procptr_t peekProcPtr(const procptr_t &addr) {
procptr_t v = 0;
if (!peekProc(addr, &v, GET_POINTER_SIZE)) {
return 0;
}
return v;
}
static inline procptr_t getVirtualFunction(const procptr_t classObject, const size_t index) {
const auto vTable = peekProcPtr(classObject);
if (!vTable) {
return 0;
}
return peekProcPtr(vTable + (index * GET_POINTER_SIZE));
}
#ifdef OS_WINDOWS
static inline procptr_t getExportedSymbol(const std::string &symbol, const procptr_t module) {
#else
/// We use a different name because the function is called by the Linux version
/// of getExportedSymbol() in case the process is running through Wine.
static inline procptr_t getWin32ExportedSymbol(const std::string &symbol, const procptr_t module) {
#endif
const auto dos = peekProc< ImageDosHeader >(module);
if (!(dos.magic[0] == 'M' && dos.magic[1] == 'Z')) {
// Invalid DOS signature
return -1;
}
procptr_t dataAddress;
if (is64Bit) {
const auto nt = peekProc< ImageNtHeaders64 >(module + dos.addressOfNtHeader);
dataAddress = nt.optionalHeader.dataDirectory[0].virtualAddress;
} else {
const auto nt = peekProc< ImageNtHeaders32 >(module + dos.addressOfNtHeader);
dataAddress = nt.optionalHeader.dataDirectory[0].virtualAddress;
}
if (!dataAddress) {
return 0;
}
const auto exportDir = peekProc< ImageExportDirectory >(module + dataAddress);
const auto funcs = peekProcVector< uint32_t >(module + exportDir.addressOfFunctions, exportDir.numberOfFunctions);
const auto names = peekProcVector< uint32_t >(module + exportDir.addressOfNames, exportDir.numberOfNames);
const auto ords = peekProcVector< uint16_t >(module + exportDir.addressOfNameOrdinals, exportDir.numberOfNames);
for (uint32_t i = 0; i < exportDir.numberOfNames; ++i) {
if (names[i]) {
const auto name = peekProcString(module + names[i], symbol.size());
if (name == symbol) {
return module + funcs[ords[i]];
}
}
}
return 0;
}
// This function returns:
// -1 in case of failure.
// 0 if the process is 32-bit.
// 1 if the process is 64-bit.
#ifdef OS_WINDOWS
static inline int8_t isProcess64Bit(const procptr_t &baseAddress) {
#else
// We use a different name because the function is called by the Linux version
// of isProcess64Bit() in case the process is running through Wine.
static inline int8_t isWin32Process64Bit(const procptr_t &baseAddress) {
#endif
const auto dos = peekProc< ImageDosHeader >(baseAddress);
if (!(dos.magic[0] == 'M' && dos.magic[1] == 'Z')) {
// Invalid DOS signature
return -1;
}
const auto nt = peekProc< ImageNtHeadersNoOptional >(baseAddress + dos.addressOfNtHeader);
if (!(nt.signature[0] == 'P' && nt.signature[1] == 'E' && nt.signature[2] == '\0' && nt.signature[3] == '\0')) {
// Invalid NT signature
return -1;
}
switch (nt.fileHeader.machine) {
case 0x14c: // IMAGE_FILE_MACHINE_I386
return 0;
default:
return 1;
}
}
#ifdef WIN32
# include "../mumble_positional_audio_win32.h"
#else
# include "../mumble_positional_audio_linux.h"
#endif
#endif
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