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         {
 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             {
 111                 j++;
 112                 break;
 113             }
 114             else
 115             {
 116                 aux_cmd.push_back(tokens[j++]);
 117             }
 118         }
 119
 120             // Creating pipe
 121         if(i!=n_commands-1)
 122         {
 123               if(pipe(file_descriptor_array[i])<0)
 124               {
 125                   cerr << "Error on pipe initialization.\n";
 126                   return -1;
 127               }
 128         }
 129             // Forking
 130         pid_t pid = fork();
 131         if(pid==0) // Primeiro processo filho
 132         {
 133             if(i!=n_commands-1)
 134             {
 135                 dup2(file_descriptor_array[i][WRITE_END],STDOUT_FILENO);
 136                 close(file_descriptor_array[i][READ_END]);
 137                 close(file_descriptor_array[i][WRITE_END]);
 138             }
 139             if(i!=0)
 140             {
 141                 dup2(file_descriptor_array[i-1][READ_END],STDIN_FILENO);
 142                 close(file_descriptor_array[i-1][WRITE_END]);
 143                 close(file_descriptor_array[i-1][READ_END]);
 144             }
 145             if(is_verbose)
 146             {
 147                 cerr << "piped_command is going to execvp aux_cmd: [";
 148                 for(unsigned short int k = 0; k < aux_cmd.size()-1; k++)
 149                     cerr << "\"" << aux_cmd[k] << "\", ";
 150                 cerr << "\"" << aux_cmd.back() << "\"]\n";
 151             }
 152             execvp(aux_cmd[0].c_str(), const_cast<char* const *>(make_argv(aux_cmd).data()));
 153             cerr << aux_cmd[0] << ": Comando não encontrado.\n";
 154             return -1;
 155         }
 156         else {
 157             if(i!=0)
 158             {
 159                 close(file_descriptor_array[i - 1][READ_END]);
 160                 close(file_descriptor_array[i - 1][WRITE_END]);
 161             }
 162         }
 163     }
 164     for(i=0; i<n_commands; i++)
 165           wait(NULL);
 166     return 1;
 167 }
 168
 169 short OpSys::simple_command(vector<string> tokens)
 170 {
 171     int status;
 172     if(is_verbose)
 173     {
 174         cerr << "execvp(\"" << tokens[0] << "\",\"";
 175         for(unsigned int i = 0; i < tokens.size()-1; i++)
 176             cerr << tokens[i] << ' ';
 177         cerr << tokens.back();
 178         cerr << "\");\n";
 179     }
 180
 181     pid_t pid = fork();
 182     if (pid == 0)
 183     {
 184         execvp(tokens[0].c_str(), const_cast<char* const *>(make_argv(tokens).data()));
 185         cerr << tokens[0] << ": command not found.\n";
 186         return -1;        // TODO: exit with cleanup
 187     }
 188     else if (pid < 0)
 189     {
 190         printf("Couldn't fork a process.");
 191         return 0;
 192     }
 193     waitpid(-1, &status, WUNTRACED);
 194     return 1;
 195 }
 196
 197 OpSys::OpSys()
 198 {
 199     cwd = get_cwd();
 200     if(cwd.empty())
 201         cerr << RED_ANSI << "Could not get the current working directory.\n" << RESET_ANSI;
 202
 203     uid_t uid = geteuid();             // Gets the effective ID of the user that started miniSHELL
 204     struct passwd pwent;
 205     struct passwd *pwent_ptr;
 206     char buffer[1024];
 207
 208         // Looks for the UDI on the password databank and saves the result on pwent
 209     getpwuid_r(uid, &pwent, buffer, sizeof buffer, &pwent_ptr);
 210     username = pwent.pw_name;   // Saves username
 211
 212     char hostname[64];
 213     gethostname(hostname, 64);
 214     this->hostname = hostname;
 215 }