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.cpp

School

Drake University *

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Course

313

Subject

Philosophy

Date

Oct 30, 2023

Type

cpp

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Uploaded by MinisterBoulderLobster32 on coursehero.com

//multiples dont work #include <iostream> #include <vector> #include <string> #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> #include <cstring> #include <fcntl.h> #include <sys/stat.h> #include <sys/param.h> #include <pwd.h> #include <ctime> #include "Tokenizer.h" using namespace std; // Function to handle single command execution with I/O redirection void executeSingleCommand(const vector<string>& command, bool is_background, string input_file = "", string output_file = "") { pid_t pid = fork(); if (pid < 0) { perror("fork"); exit(2); } if (pid == 0) { // Child process // Implement checks for I/O redirection and handle them using dup2 if (!input_file.empty()) { int in_fd = open(input_file.c_str(), O_RDONLY); if (in_fd == -1) { perror("open"); exit(2); } dup2(in_fd, 0); close(in_fd); } if (!output_file.empty()) { int out_fd = open(output_file.c_str(), O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR); if (out_fd == -1) { perror("open"); exit(2); } dup2(out_fd, 1); close(out_fd); } // Create an array of C-style strings from the vector vector<char*> args; for (const string& arg : command) { args.push_back(const_cast<char*>(arg.c_str())); } args.push_back(nullptr); // Execute the command in the child process execvp(args[0], args.data());

perror("execvp"); exit(2); } else { // Parent process if (!is_background) { int status = 0; waitpid(pid, &status, 0); if (status > 1) { exit(status); } } } } void executePipedCommands(const vector<vector<string>>& commands, bool is_background, string input_file = "", string output_file = "") { int prev_pipe_fd[2] = {-1, -1}; int next_pipe_fd[2] = {-1, -1}; for (size_t i = 0; i < commands.size(); ++i) { if (i < commands.size() - 1) { if (pipe(next_pipe_fd) == -1) { perror("pipe"); exit(2); } } pid_t pid = fork(); if (pid < 0) { perror("fork"); exit(2); } if (pid == 0) { // Child process if (i < commands.size() - 1) { close(next_pipe_fd[0]); dup2(next_pipe_fd[1], 1); close(next_pipe_fd[1]); } if (i > 0) { close(prev_pipe_fd[1]); dup2(prev_pipe_fd[0], 0); close(prev_pipe_fd[0]); } // Implement checks for I/O redirection if (i == 0) { if (!input_file.empty()) { int in_fd = open(input_file.c_str(), O_RDONLY); if (in_fd == -1) { perror("open"); exit(2); } dup2(in_fd, 0); close(in_fd); } } if (i == commands.size() - 1) {

if (!output_file.empty()) { int out_fd = open(output_file.c_str(), O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR); if (out_fd == -1) { perror("open"); exit(2); } dup2(out_fd, 1); close(out_fd); } } // Create an array of C-style strings from the vector vector<char*> args; for (const string& arg : commands[i]) { args.push_back(const_cast<char*>(arg.c_str())); } args.push_back(nullptr); // Execute the command in the child process execvp(args[0], args.data()); perror("execvp"); exit(2); } else { // Parent process if (!is_background) { // Close pipe file descriptors in the parent if (prev_pipe_fd[0] != -1) { close(prev_pipe_fd[0]); } if (prev_pipe_fd[1] != -1) { close(prev_pipe_fd[1]); } int status = 0; waitpid(pid, &status, 0); if (status > 1) { exit(status); } } // Update previous pipe file descriptors if (prev_pipe_fd[0] != -1) { close(prev_pipe_fd[0]); } if (prev_pipe_fd[1] != -1) { close(prev_pipe_fd[1]); } if (i < commands.size() - 1) { prev_pipe_fd[0] = next_pipe_fd[0]; prev_pipe_fd[1] = next_pipe_fd[1]; } } } } int main() {

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