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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>.
#ifndef MUMBLE_POSITIONAL_AUDIO_LINUX_H_
#define MUMBLE_POSITIONAL_AUDIO_LINUX_H_
#ifndef MUMBLE_POSITIONAL_AUDIO_MAIN_H_
# error "Include mumble_positional_audio_main.h instead of mumble_positional_audio_linux.h"
#endif
#include "mumble_positional_audio_utils.h"
#include <cstring>
#include <elf.h>
#include <iostream>
#include <sstream>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <sys/uio.h>
// This function returns:
// -1 in case of failure.
// 0 if the process is 32-bit.
// 1 if the process is 64-bit.
static inline int isProcess64Bit(const procptr_t &baseAddress) {
if (isWin32) {
return isWin32Process64Bit(baseAddress);
}
// We can know the process architecture by looking at its ELF header.
uint8_t elf[5];
peekProc(baseAddress, elf, sizeof(elf));
// The first 4 bytes constitute the magical number in ASCII: 0x7F 45 4c 46.
if (!(elf[0] == 0x7f && elf[1] == 'E' && elf[2] == 'L' && elf[3] == 'F')) {
return -1;
}
// The fifth byte is 1 in case the process is 32-bit or 2 in case it's 64-bit.
return elf[4] != 1;
}
// This function returns:
// -1 in case of failure.
// 0 if the process is not running through Wine.
// 1 if the process is running through Wine.
static inline int8_t isProcessWin32(const procid_t &pid) {
std::stringstream ss;
ss << "/proc/";
ss << static_cast< unsigned long >(pid);
ss << "/exe";
char *path = realpath(ss.str().c_str(), nullptr);
if (!path) {
return -1;
}
const char *filename = basename(path);
if (strcmp(filename, "wine-preloader") == 0 || strcmp(filename, "wine64-preloader") == 0) {
free(path);
return 1;
}
// basename() returns a pointer to the basename's position in the string passed as argument.
// For that reason we cannot free 'path' before the if statement.
free(path);
return 0;
}
static inline procptr_t getModuleAddr(const procid_t &pid, const wchar_t *modname) {
std::wstring modnameWide(modname);
std::string modnameNonWide(modnameWide.begin(), modnameWide.end());
std::stringstream ss;
ss << std::string("/proc/");
ss << static_cast< unsigned long >(pid);
ss << std::string("/maps");
std::string mapsFn = ss.str();
std::string maps = readFile(mapsFn);
if (maps.size() == 0) {
return 0;
}
std::stringstream ssPath(maps);
while (ssPath.good()) {
std::string baseaddr;
int ch;
while (1) {
ch = ssPath.get();
if (ch == '-') {
break;
} else if (ch == EOF) {
return 0;
}
baseaddr.push_back(static_cast< char >(ch));
}
// seek to perms
do {
ch = ssPath.get();
if (ch == EOF) {
return 0;
}
} while (ch != ' ');
// seek to offset
do {
ch = ssPath.get();
if (ch == EOF) {
return 0;
}
} while (ch != ' ');
// seek to dev
do {
ch = ssPath.get();
if (ch == EOF) {
return 0;
}
} while (ch != ' ');
// seek to inode
do {
ch = ssPath.get();
if (ch == EOF) {
return 0;
}
} while (ch != ' ');
// seek to pathname
do {
ch = ssPath.get();
if (ch == EOF) {
return 0;
}
} while (ch != ' ');
// eat spaces until we're at the beginning of pathname.
while (ch == ' ') {
if (ch == EOF) {
return 0;
}
ch = ssPath.get();
}
ssPath.unget();
std::string pathname;
while (1) {
ch = ssPath.get();
if (ch == '\n') {
break;
} else if (ch == EOF) {
return 0;
}
pathname.push_back(static_cast< char >(ch));
};
// OK, we found 'em!
// Only treat path as a real path if it starts with /.
if (pathname.size() > 0 && pathname.at(0) == '/') {
// Find the basename.
size_t lastSlash = pathname.find_last_of('/');
if (pathname.size() > lastSlash + 1) {
std::string basename = pathname.substr(lastSlash + 1);
if (basename == modnameNonWide) {
unsigned long addr = strtoul(baseaddr.c_str(), nullptr, 16);
return addr;
}
}
}
}
return 0;
}
static inline bool peekProc(const procptr_t &addr, void *dest, const size_t &len) {
struct iovec in;
in.iov_base = reinterpret_cast< void * >(addr); // Address from target process
in.iov_len = len; // Length
struct iovec out;
out.iov_base = dest;
out.iov_len = len;
ssize_t nread = process_vm_readv(pPid, &out, 1, &in, 1, 0);
return (nread != -1 && static_cast< size_t >(nread) == in.iov_len);
}
template< typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Dyn, typename Elf_Sym >
static inline procptr_t getExportedSymbolInternal(const std::string &symbol, const procptr_t module) {
procptr_t hashTable = 0;
procptr_t strTable = 0;
procptr_t symTable = 0;
const auto ehdr = peekProc< Elf_Ehdr >(module);
const auto phdr = peekProcVector< Elf_Phdr >(module + ehdr.e_phoff, ehdr.e_phnum);
for (size_t i = 0; i < phdr.size(); ++i) {
if (phdr[i].p_type == PT_DYNAMIC) {
const auto dyn = peekProcVector< Elf_Dyn >(module + phdr[i].p_vaddr, phdr[i].p_memsz / sizeof(Elf_Dyn));
for (size_t j = 0; j < dyn.size(); ++j) {
switch (dyn[j].d_tag) {
case DT_HASH:
hashTable = dyn[j].d_un.d_ptr;
break;
case DT_STRTAB:
strTable = dyn[j].d_un.d_ptr;
break;
case DT_SYMTAB:
symTable = dyn[j].d_un.d_ptr;
break;
}
if (hashTable && strTable && symTable) {
break;
}
}
break;
}
}
// Hash table pseudo-struct:
// uint32_t nBucket;
// uint32_t nChain;
// uint32_t bucket[nBucket];
// uint32_t chain[nChain];
const auto nChain = peekProc< uint32_t >(hashTable + sizeof(uint32_t));
for (uint32_t i = 0; i < nChain; ++i) {
const auto sym = peekProc< Elf_Sym >(symTable + sizeof(Elf_Sym) * i);
const auto name = peekProcString(strTable + sym.st_name, symbol.size());
if (name == symbol) {
return module + sym.st_value;
}
}
return 0;
}
static inline procptr_t getExportedSymbol(const std::string &symbol, const procptr_t module) {
if (isWin32) {
return getWin32ExportedSymbol(symbol, module);
}
if (is64Bit) {
return getExportedSymbolInternal< Elf64_Ehdr, Elf64_Phdr, Elf64_Dyn, Elf64_Sym >(symbol, module);
} else {
return getExportedSymbolInternal< Elf32_Ehdr, Elf32_Phdr, Elf32_Dyn, Elf32_Sym >(symbol, module);
}
}
static void generic_unlock() {
pModule = 0;
pPid = 0;
}
static bool initialize(const std::multimap< std::wstring, unsigned long long int > &pids, const wchar_t *procname,
const wchar_t *modname = nullptr) {
pModule = 0;
if (!pids.empty()) {
auto iter = pids.find(std::wstring(procname));
if (iter != pids.end()) {
pPid = static_cast< procid_t >(iter->second);
} else {
pPid = 0;
}
} else {
pPid = 0;
}
if (!pPid) {
return false;
}
pModule = getModuleAddr(procname);
if (!pModule) {
pPid = 0;
return false;
}
int8_t ret = isProcessWin32(pPid);
if (ret == -1) {
generic_unlock();
return false;
}
isWin32 = ret;
ret = isProcess64Bit(pModule);
if (ret == -1) {
generic_unlock();
return false;
}
is64Bit = ret;
if (modname) {
pModule = getModuleAddr(modname);
if (!pModule) {
pPid = 0;
return false;
}
}
return true;
}
#endif
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