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     if(is_verbose)
  86     {
  87         cerr << "Running piped_command with ";
  88         cerr << "tokens: [";
  89         for(unsigned short int k = 0; k < tokens.size()-1; k++)
  90             cerr << "\"" << tokens[k] << "\", ";
  91         cerr << "\"" << tokens.back() << "\"]\n";
  92     }
  93
  94     int n_commands = pipe_count + 1;
  95     int file_descriptor_array[10][2];
  96     unsigned short i, j=0;
  97     string pipe_str = "|";
  98
  99     for(i=0; i < n_commands; i++)
 100     {
 101         if (n_commands > 10)
 102         {               // This is an arbitrary decision. Allowing for more pipes is easily possible.
 103             cerr << "More pipes than supported.\n";
 104             return -1;
 105         }
 106         vector<string> aux_cmd;
 107         for(;j<tokens.size();)
 108         {
 109             if (!tokens[j].compare(pipe_str))
 110             {               //  We've hit a pipe character.
 111                 j++;        //  Skip a position for the next iteration.
 112                 break;
 113             }
 114             else
 115             {               /*  Current token is not a pipe character
 116                              *  so let's add it to our auxiliary command vector */
 117                 aux_cmd.push_back(tokens[j++]);
 118             }
 119         }
 120
 121             // Creating pipe
 122         if(i!=n_commands-1)
 123         {
 124               if(pipe(file_descriptor_array[i])<0)
 125               {
 126                   cerr << "Error on pipe initialization.\n";
 127                   return -1;
 128               }
 129         }
 130             // Forking
 131         pid_t pid = fork();
 132         if(pid==0) // Primeiro processo filho
 133         {
 134             if(i!=n_commands-1)
 135             {
 136                 dup2(file_descriptor_array[i][WRITE_END],STDOUT_FILENO);
 137                 close(file_descriptor_array[i][READ_END]);
 138                 close(file_descriptor_array[i][WRITE_END]);
 139             }
 140             if(i!=0)
 141             {
 142                 dup2(file_descriptor_array[i-1][READ_END],STDIN_FILENO);
 143                 close(file_descriptor_array[i-1][WRITE_END]);
 144                 close(file_descriptor_array[i-1][READ_END]);
 145             }
 146             if(is_verbose)
 147             {
 148                 cerr << "piped_command is going to execvp aux_cmd: [";
 149                 for(unsigned short int k = 0; k < aux_cmd.size()-1; k++)
 150                     cerr << "\"" << aux_cmd[k] << "\", ";
 151                 cerr << "\"" << aux_cmd.back() << "\"]\n";
 152             }
 153             execvp(aux_cmd[0].c_str(), const_cast<char* const *>(make_argv(aux_cmd).data()));
 154             cerr << aux_cmd[0] << ": Comando não encontrado.\n";
 155             return -1;
 156         }
 157         else {
 158             if(i!=0)
 159             {
 160                 close(file_descriptor_array[i - 1][READ_END]);
 161                 close(file_descriptor_array[i - 1][WRITE_END]);
 162             }
 163         }
 164     }
 165     for(i=0; i<n_commands; i++)
 166           wait(NULL);
 167     return 1;
 168 }
 169
 170 void OpSys::show_history()              // TODO: save (and read) history on a file? use Bourne Again's history??
 171 {
 172     unsigned short i = 0, j;
 173     for(vector<string> command : history)
 174     {
 175         string command_str = "";
 176         for(j=0; j<command.size()-1; j++)
 177         {
 178             command_str += command[j] + ' ';
 179         }
 180         command_str += command.back();
 181         printf("%-20hu\t%s\n", i++,  command_str.c_str());       // You may think this is unoptimized... which would actually be quite true.
 182     }
 183     fflush(stdout);
 184 }
 185
 186 short OpSys::simple_command(vector<string> tokens)
 187 {
 188     int status;
 189     if(is_verbose)
 190     {
 191         cerr << "execvp(\"" << tokens[0] << "\",\"";
 192         for(unsigned int i = 0; i < tokens.size()-1; i++)
 193             cerr << tokens[i] << ' ';
 194         cerr << tokens.back();
 195         cerr << "\");\n";
 196     }
 197
 198     pid_t pid = fork();
 199     if (pid == 0)
 200     {
 201         execvp(tokens[0].c_str(), const_cast<char* const *>(make_argv(tokens).data()));
 202         cerr << tokens[0] << ": command not found.\n";
 203         return -1;        // TODO: exit with cleanup
 204     }
 205     else if (pid < 0)
 206     {
 207         printf("Couldn't fork a process.");
 208         return 0;
 209     }
 210     waitpid(-1, &status, WUNTRACED);
 211     return 1;
 212 }
 213
 214 OpSys::OpSys()
 215 {
 216     cwd = get_cwd();
 217     if(cwd.empty())
 218         cerr << RED_ANSI << "Could not get the current working directory.\n" << RESET_ANSI;
 219
 220     uid_t uid = geteuid();             // Gets the effective ID of the user that started miniSHELL
 221     struct passwd pwent;
 222     struct passwd *pwent_ptr;
 223     char buffer[1024];
 224
 225         // Looks for the UDI on the password databank and saves the result on pwent
 226     getpwuid_r(uid, &pwent, buffer, sizeof buffer, &pwent_ptr);
 227     username = pwent.pw_name;   // Saves username
 228
 229     char hostname[64];
 230     gethostname(hostname, 64);
 231     this->hostname = hostname;
 232 }