#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

int main();
void parent(int pid);
void child();

int main()
{
	int ret;
	if( (ret=fork()) > 0 )
		parent(ret);
	else if ( ret == 0 )
		child();
	else 
		perror("fork() failed");
	exit(0);
}

void parent(int pid)
{
int child_ExitVal;

/*The parent only invokes the wait() if the command is a foreground command,** i.e. there is no '&' at the end of the line*/
	if (wait(&child_ExitVal) < 0
	{	perror("wait");
		exit(1);
	}


}

void child()
{
	char *argv[100]; 
/*this part should use strtok.  But I read it from the Unix manual, I'm still unable to manipulate the command typed in so that it is usable by execvp.*/

	argv[0] = "ls";
	argv[1] = "-l";
	argv[2] = "/";
	argv[3] = NULL;
	execvp(argv[0], argv);
/* If the program arrives here, an error must have occurred otherwise a different program image would be active.*/
	perror("execvp");
	exit(1); 
}

#include <stdlib.h>
#include <stdio.h>
#include <string.h>	// Mainly for strtok

#define MAX_ARGS 2

char * PATH = "MyShell:$:";

char *path; //for the command path

typedef struct{
	char *cmd_path;	//path of command
	int argc;	//number of args for the cmd
	char *argv[MAX_ARGS];
	char cmd_suffix;
}commandStruct;

int runCommand(commandStruct * command1);

int main() {
	
	system("clear");
	int flag = 1;
	do {
		char buffer[256], *input;
		pid_t child;
		int childstatus, status;	//For Fork
	
		int x = 1;
		char *cmd;			//For strtok

		char *command;			//The command
		int cmdlen;

		commandStruct *command1 = (commandStruct*) malloc(sizeof(commandStruct));	
		command1->argc = 1;
		
		printf("\n%s", PATH);
		fflush(stdout);
		input = fgets(buffer, 256, stdin);

		cmdlen = strlen(input);		//Take out new line char
		if (input[cmdlen-1] == '\n') {	//
			input[cmdlen-1] = '\0';	//
		}				//

		//Get first token (the command) from input
       		cmd = strtok(input, " ");
		command = cmd;

		if (strcmp(command, "exit") == 0){
			flag = 0;
		}	

		command1->cmd_path = command;
		command1->argv[0] = command1->cmd_path;
	
		//Loop thru until whole command is tokenized
	        while (1)
	        {
	               	//Check command has no more than 2 args
			if (command1->argc > 3) {
				printf("\nError! Too many command arguements!\n");
				break;
			}

			//Extract next part of command
	                cmd = strtok(NULL, " ");

	                //Check that there is nothing else to extract
	                if (cmd == NULL)
	                {
	                        //printf("Command Tokenised");
				break;
			}

			command1->argv[command1->argc] = cmd;	//put arg into arg array
			command1->argc = command1->argc+1;	//increase count of args
		         	
	        }

		printf("Number of args: %d\n", command1->argc);
	
		childstatus = fork();
		if (childstatus != 0) { //if parent process is running
			wait(&status);
		} else {
			/* This area is child process */
			runCommand(command1);
			return(0);
		}	

	}while (flag == 1);

	return 0;
	exit(0);
}

int runCommand(commandStruct * command1) {
	
	printf("Command: %s\n", command1->cmd_path);
	execvp(command1->cmd_path, command1->argv);
	//printf("%s\n%s\n%s\n", command1->argv[0], command1->argv[1], command1->argv[2]);
	return 1;

}