Sources/opsys.cpp

   1 #include "Headers/opsys.h"
   2
   3 #include <sys/param.h>      // MAXPATHLEN
   4 #include <sys/wait.h>       // waitpid
   5 #include <unistd.h>         // getcwd, fork, chdir, geuid, gethostname, execvp
   6 #include <pwd.h>            // struct passwd, getpwuid_r
   7
   8 using std::cin;
   9 using std::cout;
  10 using std::cerr;
  11
  12 OpSys OS;       // Global OpSys variable. Should be accessible to all modules.
  13 bool exit_program = false;
  14
  15 void signal_handler(int s)
  16 {
  17     if (s==SIGINT)
  18     {
  19         cout << "\nSIGINT (Ctrl+C) received. Code " << s << ". Exiting.\n";
  20         exit_program = true;  // We'll do this instead of an exit(0) in order to allow for cleanup.
  21     }
  22
  23     if (s==SIGHUP)
  24     {
  25         cout << "\nSIGHUP received. Code " << s << ". Exiting.\n";
  26         exit_program = true;  // We'll do this instead of an exit(0) in order to allow for cleanup.
  27     }
  28 }
  29
  30 SignalHandler::SignalHandler()
  31 {
  32     signal_action.sa_handler = signal_handler;
  33     sigemptyset(&signal_action.sa_mask);
  34     signal_action.sa_flags = 0;
  35     sigaction(SIGINT, &signal_action, NULL);
  36 }
  37
  38 string OpSys::get_cwd()
  39 {
  40     char temp[MAXPATHLEN];
  41     return getcwd(temp, sizeof(temp)) ? std::string( temp ) : std::string("");
  42 }
  43
  44 void OpSys::change_dir(vector<string> command)
  45 {
  46     if (command.size() == 1 || !command[1].compare("~") || !command[1].compare("$HOME"))
  47     {           // User wants to cd into $HOME/~.
  48         chdir(getenv("HOME"));
  49         this->cwd = get_cwd();
  50         cwd_changed = true;
  51         return;
  52     }
  53
  54     string cmd;
  55
  56     for(unsigned short int i = 1; i < command.size(); i++)      // TODO: unneeded?
  57         cmd += command[i];
  58
  59     if (chdir(cmd.c_str()))
  60     {
  61                 // Couldn't get to change dirs
  62         cerr << "minish2: cd: " << cmd << ": Arquivo ou diretório não encontrado.\n";
  63     }
  64     else
  65     {
  66                 // chdir worked. and tell Prompt to act accordingly.
  67         this->cwd = get_cwd();      // Update the OpSys OS's current cwd
  68         cwd_changed = true;         // Signals a cwd change to Prompt.
  69     }
  70 }
  71
  72 vector<const char*> make_argv(vector<string>const& in)
  73 {
  74     vector<const char*> out;
  75     out.reserve(in.size() + 1);
  76     for (const auto& s : in)
  77         out.push_back(s.data());
  78     out.push_back(nullptr);
  79     out.shrink_to_fit();
  80     return out;
  81 }
  82
  83 short OpSys::piped_command(vector<string> tokens, int pipe_count)
  84 {
  85     cerr << "I'm in piped_command\n";
  86     int n_commands = pipe_count + 1;
  87     int file_descriptor_array[10][2];
  88     unsigned short i, j=0;
  89     string pipe_str = "|";
  90
  91     cerr << "tokens: [";
  92     for(unsigned short int k = 0; k < tokens.size()-1; k++)
  93         cerr << "\"" << tokens[k] << "\", ";
  94     cerr << "\"" << tokens.back() << "\"]\n";
  95
  96     for(i=0; i < n_commands; i++)
  97     {
  98         if (n_commands > 10)
  99         {
 100             cerr << "More pipes than supported.\n";
 101             return -1;
 102         }
 103         vector<string> aux_cmd;
 104         for(;j<tokens.size();)
 105         {
 106             if (!tokens[j].compare(pipe_str))
 107             {
 108                 j++;
 109                 cerr << "BREAKING\n";
 110                 break;
 111             }
 112             else
 113             {
 114                 aux_cmd.push_back(tokens[j++]);
 115                 cerr << "aux_cmd: [";
 116                 for(unsigned short int k = 0; k < aux_cmd.size()-1; k++)
 117                     cerr << "\"" << aux_cmd[k] << "\", ";
 118                 cerr << "\"" << aux_cmd.back() << "\"]\n";
 119             }
 120         }
 121
 122             // Creating pipe
 123         if(i!=n_commands-1)
 124         {
 125               if(pipe(file_descriptor_array[i])<0)
 126               {
 127                   cerr << "Error on pipe initialization.\n";
 128                   return -1;
 129               }
 130         }
 131             // Forking
 132         pid_t pid = fork();
 133         if(pid==0) // Primeiro processo filho
 134         {
 135             if(i!=n_commands-1)
 136             {
 137                 dup2(file_descriptor_array[i][WRITE_END],STDOUT_FILENO);
 138                 close(file_descriptor_array[i][READ_END]);
 139                 close(file_descriptor_array[i][WRITE_END]);
 140             }
 141             if(i!=0)
 142             {
 143                 dup2(file_descriptor_array[i-1][READ_END],STDIN_FILENO);
 144                 close(file_descriptor_array[i-1][WRITE_END]);
 145                 close(file_descriptor_array[i-1][READ_END]);
 146             }
 147             execvp(aux_cmd[0].c_str(), const_cast<char* const *>(make_argv(aux_cmd).data()));
 148             cerr << aux_cmd[0] << ": Comando não encontrado.\n";
 149             return -1;
 150         }
 151         else
 152         {
 153             if(i!=0)
 154             {
 155                 close(file_descriptor_array[i - 1][READ_END]);
 156                 close(file_descriptor_array[i - 1][WRITE_END]);
 157             }
 158         }
 159     }
 160     for(i=0; i<n_commands; i++)
 161           wait(NULL);
 162     return 1;
 163 }
 164
 165 short OpSys::simple_command(vector<string> tokens)
 166 {
 167     int status;
 168     if(is_verbose)
 169     {
 170         cerr << "execvp(\"" << tokens[0] << "\",\"";
 171         for(unsigned int i = 0; i < tokens.size()-1; i++)
 172             cerr << tokens[i] << ' ';
 173         cerr << tokens.back();
 174         cerr << "\");\n";
 175     }
 176
 177     pid_t pid = fork();
 178     if (pid == 0)
 179     {
 180         execvp(tokens[0].c_str(), const_cast<char* const *>(make_argv(tokens).data()));
 181         cerr << tokens[0] << ": command not found.\n";
 182         return -1;        // TODO: exit with cleanup
 183     }
 184     else if (pid < 0)
 185     {
 186         printf("Couldn't fork a process.");
 187         return 0;
 188     }
 189     waitpid(-1, &status, WUNTRACED);
 190     return 1;
 191 }
 192
 193 OpSys::OpSys()
 194 {
 195     cwd = get_cwd();
 196     if(cwd.empty())
 197         cerr << RED_ANSI << "Could not get the current working directory.\n" << RESET_ANSI;
 198
 199     uid_t uid = geteuid();             // Gets the effective ID of the user that started miniSHELL
 200     struct passwd pwent;
 201     struct passwd *pwent_ptr;
 202     char buffer[1024];
 203
 204         // Looks for the UDI on the password databank and saves the result on pwent
 205     getpwuid_r(uid, &pwent, buffer, sizeof buffer, &pwent_ptr);
 206     username = pwent.pw_name;   // Saves username
 207
 208     char hostname[64];
 209     gethostname(hostname, 64);
 210     this->hostname = hostname;
 211 }