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// Copyright 2005-2017 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_PLUGIN_LINUX_H_
#define MUMBLE_PLUGIN_LINUX_H_
#include <sys/uio.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string>
#include <cstring>
#include <iostream>
#include <fstream>
#include <sstream>
#include "mumble_plugin.h"
pid_t pPid;
int is64Bit;
static procptr_t pModule;
static inline std::string readAll(std::string fn) {
std::ifstream ifs;
ifs.open(fn.c_str(), std::ifstream::binary);
std::string content;
char buf[256];
while (ifs.good()) {
ifs.read(&buf[0], sizeof(buf));
size_t nread = ifs.gcount();
if (nread > 0) {
content.append(&buf[0], nread);
}
}
return content;
}
// This function returns 0 if the process is 32-bit and 1 if it's 64-bit.
// In case of failure, it returns -1.
static inline int checkProcessIs64Bit(const pid_t pid)
{
// We can know the process architecture by looking at its ELF header.
char elf[5];
std::stringstream ss;
ss << "/proc/";
ss << static_cast<unsigned long>(pid);
ss << "/exe";
std::ifstream ifs;
ifs.open(ss.str(), std::ifstream::binary);
if (!ifs.is_open()) {
return -1;
}
ifs.read(elf, LENGTH_OF(elf));
ifs.close();
if (ifs.gcount() != LENGTH_OF(elf)) {
return -1;
}
// 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;
}
static inline procptr_t getModuleAddr(pid_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 = readAll(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(), NULL, 16);
return addr;
}
}
}
}
return 0;
}
static inline procptr_t getModuleAddr(const wchar_t *modname) {
return getModuleAddr(pPid, modname);
}
static inline bool peekProc(procptr_t base, void *dest, size_t len) {
struct iovec in;
in.iov_base = reinterpret_cast<void *>(base); // 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<class T>
bool peekProc(procptr_t base, T &dest) {
struct iovec in;
in.iov_base = reinterpret_cast<void *>(base); // Address from target process
in.iov_len = sizeof(T); // Length
struct iovec out;
out.iov_base = &dest;
out.iov_len = sizeof(T);
ssize_t nread = process_vm_readv(pPid, &out, 1, &in, 1, 0);
return (nread != -1 && static_cast<size_t>(nread) == in.iov_len);
}
static inline procptr_t peekProcPtr(procptr_t base) {
procptr_t v = 0;
if (!peekProc(base, &v, is64Bit ? 8 : 4)) {
return 0;
}
return v;
}
static bool inline initialize(const std::multimap<std::wstring, unsigned long long int> &pids, const wchar_t *procname, const wchar_t *modname = NULL) {
pModule = 0;
if (! pids.empty()) {
std::multimap<std::wstring, unsigned long long int>::const_iterator iter = pids.find(std::wstring(procname));
if (iter != pids.end())
pPid = static_cast<pid_t>(iter->second);
else
pPid = 0;
} else {
pPid = 0;
}
if (pPid == 0)
return false;
int result = checkProcessIs64Bit(pPid);
if (result == -1) {
return false;
}
is64Bit = result;
pModule = getModuleAddr(modname ? modname : procname);
if (pModule == 0) {
pPid = 0;
return false;
}
return true;
}
static void generic_unlock() {
pModule = 0;
pPid = 0;
}
#endif
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