Shell_project.c

/**
UNIX Shell Project

Sistemas Operativos
Grados I. Informatica, Computadores & Software
Dept. Arquitectura de Computadores - UMA

Some code adapted from "Fundamentos de Sistemas Operativos", Silberschatz et al.

To compile and run the program:
   $ gcc Shell_project.c job_control.c -o Shell
   $ ./Shell          
	(then type ^D to exit program)

**/

#include "job_control.h"   // remember to compile with module job_control.c 
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h>
#include <unistd.h> 
#include <sys/types.h> 
#include <sys/wait.h>




#define MAX_LINE 256 /* 256 chars per line, per command, should be enough. */
#define ANSI_COLOR_RED     "\x1b[31m"
#define ANSI_COLOR_GREEN   "\x1b[32m"
#define ANSI_COLOR_YELLOW  "\x1b[33m"
#define ANSI_COLOR_BLUE    "\x1b[34m"
#define ANSI_COLOR_MAGENTA "\x1b[35m"
#define ANSI_COLOR_CYAN    "\x1b[36m"
#define ANSI_COLOR_RESET   "\x1b[0m"

// -----------------------------------------------------------------------
//                            MAIN          
// -----------------------------------------------------------------------
job * lista;

void manej(){
	
	enum status status_res; 
	int estado, info;
	job * current;
	int x = list_size(lista);
	for (x; x != 0; x--){
		current = get_item_bypos(lista, x);
		status_res = current -> state;
		if(current -> state != FOREGROUND){
				int pid_wait = waitpid(current -> pgid, &estado  ,WNOHANG | WUNTRACED | WCONTINUED);
				status_res = analyze_status(estado, &info);
		
				if (pid_wait == current -> pgid){
					printf("Process pid: %s, pid=%i, estado = %s\n", current->command, pid_wait, status_strings[status_res]);
					fflush(stdout);
					if (status_res == CONTINUED) current -> state = BACKGROUND; //Check if its running in background and updates state to background
					else if (status_res == SUSPENDED){     //Checks if it's suspended and changes status to stopped
					current -> state = STOPPED; 
					}
					else if((status_res == EXITED || status_res == SIGNALED)) { //if it has exited or been signaled, it is deleted from the list
						block_SIGCHLD();
						int x = delete_job(lista, current);
						unblock_SIGCHLD();
					}
				}
		}
	}
	
}

int main(void)
{
	char inputBuffer[MAX_LINE]; /* buffer to hold the command entered */
	int background;             /* equals 1 if a command is followed by '&' */
	char *args[MAX_LINE/2];     /* command line (of 256) has max of 128 arguments */
	// probably useful variables:
	int pid_fork, pid_wait; /* pid for created and waited process */
	int status;             /* status returned by wait */
	enum status status_res; /* status processed by analyze_status() */
	int info;				/* info processed by analyze_status() */
	char pwd[MAX_LINE];
	ignore_terminal_signals(); //Ignore
	lista = new_list("lista");
	signal(SIGCHLD, manej);		//If a signal is detected invoke manej()
	printf(ANSI_COLOR_MAGENTA "Welcome to the best shell you'll ever see. Use ctrl^D or 'exit' to exit the Shell, use any unix command to execute it and use 'zurprise' for a... surprise ;)\n");
	while (1)   /* Program terminates normally inside get_command() after ^D is typed*/
	{   	
		
		
		
		getcwd(pwd,MAX_LINE);
		printf(ANSI_COLOR_GREEN "%s" ,pwd);
		printf(ANSI_COLOR_BLUE " COMMAND:" ANSI_COLOR_RESET);
		fflush(stdout);
		
		get_command(inputBuffer, MAX_LINE, args, &background);  /* get next command */
		
		if(args[0]==NULL){ continue;   // if empty command get back to asking for a command
		}else if(strcmp(args[0], "cd") == 0){ 
			if(args[1] == NULL){ continue;}
			else if(chdir(args[1])!=0) printf( ANSI_COLOR_RED "Error, cant access %s\n" ANSI_COLOR_RESET, args[1]);
		
		}else if(strcmp(args[0], "jobs") == 0){ 
			print_job_list(lista);

		}else if(strcmp(args[0], "fg") == 0){ // Takes a background element and put it in foreground
				int position, status;
				if(empty_list(lista)){ 
					printf("The list is empty.\n");
					continue;
				}else if (args[1] == NULL){ 
					position = 1;
				}else{ 
					position = atoi(args[1]);
				}
				if (get_item_bypos(lista, position) == NULL) printf("Couldn't find element number %d\n", position);
				else{
					job * task = get_item_bypos(lista, position);
				
					set_terminal(task -> pgid);
					task -> state = FOREGROUND;
					killpg(task->pgid, SIGCONT);
					waitpid(task->pgid, &status, WUNTRACED); //Waiting for it to finish or stop or something
					set_terminal(getpid()); //Parent I think is getting the shell back
				
					status_res = analyze_status(status, &info); //Need to know what happened to our sweet child of mine
					printf("Foreground pid: %d, command: %s, %s, info: %d\n", task->pgid, task->command, status_strings[status_res], info);
					
				if(status_res == SUSPENDED){ //Suspended so update status to STOPPED
					task->state = STOPPED;
				} else if(status_res == EXITED || status_res == SIGNALED){ //If it ended by existing or being sginaled we take it out of the list
					block_SIGCHLD();
					delete_job(lista, task);
					unblock_SIGCHLD();
				}
				} continue;
		
		}else if (strcmp(args[0], "bg") == 0){  //Takes a stopped element and runs it in background
			int position, status;
			if (args[1] == NULL){
				position = 1;
			} else {
				position = atoi(args[1]);
			}
			job * task = get_item_bypos(lista, position);
			
			task->state = BACKGROUND;
			killpg(task->pgid, SIGCONT); //continue signal
			printf("Background pid: %d, command: %s\n", task->pgid, task->command);

		}else if((strcmp(args[0], "exit") == 0)){ 
			printf(ANSI_COLOR_YELLOW "According to quantum superposition you're in and out of the Shell at the same time. However, once we've measured you, we can affirm you're out. Bye product of the BigBang.\n\n"); 
			exit(0);
		}else if(strcmp(args[0], "zurprise") == 0) {
				printf("Auto redirecting would've been nice but the internet seems to not know how to do that so: https://tinyurl.com/zurprise\n");
		}
		else if(strcmp(args[0], "idk") == 0){ 
			printf( ANSI_COLOR_MAGENTA "Me neither...\n");
		}
		else if(strcmp(args[0], "hakuna") == 0){ 
			printf( ANSI_COLOR_MAGENTA "MATATA! \n");
		}
		else if(strcmp(args[0], "gg") == 0){ 
			printf( ANSI_COLOR_MAGENTA "ez\n");
		}
		else if(strcmp(args[0], "idc") == 0){ 
			printf( ANSI_COLOR_MAGENTA "Who asked lmao\n");
		}
		else if(strcmp(args[0], "never") == 0){ 
			printf( ANSI_COLOR_MAGENTA "gonna give you up!\n");
		}
		else if(strcmp(args[0], "i") == 0){ 
			printf( ANSI_COLOR_MAGENTA "wanna be the very best, like noone ever was!\n");
		}
		else if(strcmp(args[0], "ping") == 0){ 
			printf( ANSI_COLOR_MAGENTA "pong\n");
		}
		else{
		
		pid_fork = fork();	
		if(pid_fork == 0){ //We are in the child process
			new_process_group(getpid());
				
		if( background == 0){ 
			set_terminal(getpid()); // works properly
			
		}
			restore_terminal_signals();
			 execvp(args[0], args);	
			// cant insert variables in perror so there it goes, a beautiful printf
			printf(ANSI_COLOR_RED "Error: command not found: %s\n" ANSI_COLOR_RESET, args[0]);
			
			exit(EXIT_FAILURE);

			//continue;
		}else if (pid_fork > 0){
			 //We are in the parent process
			
				if(background != 1){	//If it isnt in background, parent has to wait for its termination
				pid_wait = waitpid(pid_fork,&status,WUNTRACED);
				status_res = analyze_status(status, &info);
				if(status_res == SUSPENDED)add_job(lista, new_job( pid_fork, args[0], STOPPED));	//If it didnt end but got suspended, we add it to the list
				set_terminal(getpid());
	
				printf("Foreground pid: %d command: %s, %s , info: %d\n", pid_fork, args[0], status_strings[status_res], info);

				}else{	//If it is in background we just add it to the list and move on cause who cares
					add_job(lista, new_job( pid_fork, args[0], BACKGROUND));
					printf("Background job running... pid: %d command: %s\n", pid_fork, args[0]); 
				}
			
			
		}else {
			printf("Error creating child\n");	//F in the chat
		}continue;
	}
		/* the steps are:
			 (1) fork a child process using fork() 
			 (2) the child process will invoke execvp()
			 (3) if background == 0, the parent will wait, otherwise continue 
			 (4) Shell shows a status message for processed command 
			 (5) loop returns to get_commnad() function
		*/

	} // end while
}