getProcUser()

The process user is retrieved from proc/[PID]/status. From this file we can retrieve the UID, which is the ID of the process owner. To retrieve this ID, open a read stream on /etc/passwd and search for "Uid:". The UID is the next token on that line.

Once we have the UID, we can look up the username from /etc/passwd.

string ProcessParser::getProcUser(string pid)
{
    string line;
    string name = "Uid:";
    string result ="";
    ifstream stream = Util::getStream((Path::basePath() + pid + Path::statusPath()));
    // Getting UID for user
    while (std::getline(stream, line)) {
        if (line.compare(0, name.size(),name) == 0) {
            istringstream buf(line);
            istream_iterator<string> beg(buf), end;
            vector<string> values(beg, end);
            result =  values[1];
            break;
        }
    }
    stream = Util::getStream("/etc/passwd");
    name =("x:" + result);
    // Searching for name of the user with selected UID
    while (std::getline(stream, line)) {
        if (line.find(name) != std::string::npos) {
            result = line.substr(0, line.find(":"));
            return result;
        }
    }
    return "";
}