32197721_myshell.c

#define _GNU_SOURCE
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <stdbool.h>
#include <fcntl.h>
#include <dirent.h>

int b=0,L=0;   //background와 redirection을 위한 조건
int tokenize(char* buf,char* delims,char* tokens[],int maxTokens)
	
{    
	char *token;
	int token_count = 0;
        token = strtok(buf,delims);
        while(token != NULL && token_count <maxTokens){
	        tokens[token_count++] = token;
                token = strtok(NULL,delims);
	}	
	tokens[token_count] = NULL;
     return token_count;

}

bool run(char* line)
{       
	int token_count; char* tokens[1024]; char* delims=" \n\t";
       	int fd_redir,fd_bg, i,j;
        char* tokencp[1024];
        pid_t child = 0;
        b=0; L=0;
        token_count = tokenize(line,delims,tokens,sizeof(tokens)/sizeof(char*));
        for(i = 0; i< token_count; i++){
	        if(!strcmp(tokens[i],">"))
                {
	                L++;
                }
                if(!strcmp(tokens[i],"&"))
                {
                        b++;
                }
                printf("입력된 명령어는 : %s \n",tokens[i]);
	}
        if(strcmp(tokens[0],"cd") == 0){       //CD 구현
                if(chdir(tokens[1])!=0){
                	perror("cd");
		}
                return true;
	}
	if(!b) {
                if((child = fork())==0) {
                	execvp( tokens[0],tokens);
                	_exit(0);
                }
        } else if(b){     // background일때
                if((child = fork())==0)
                {      
		       	fd_bg = open("/dev/null",O_RDONLY);
                        dup2(fd_bg,STDOUT_FILENO);
                        execvp( tokens[0],tokens);
                        _exit(0);
		}
        }else if(L)        //redirection 일떄
        {
	 	if((child=fork())==0)
                {        
                        fd_redir = open(tokens[3],O_RDWR | O_CREAT | O_TRUNC,0641);
                        dup2(fd_redir,STDOUT_FILENO);
                        close(fd_redir);
                        execvp(tokens[0],tokens);
                        _exit(0);
	        }
        }
        memset(tokens, '\0', 1024);
        return 1;
}

int main()
{
	char line[1024];
        while(1)
        {       
		printf("%s$", get_current_dir_name());
                fgets(line, sizeof(line)-1, stdin);
                if(run(line) == false) break;
        }
        return 0;

}