#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>
#include <unistd.h>
#include <pwd.h>
char* get_mode(mode_t m,char* str)
{
   if(S_ISREG(m))
       strcpy(str,"-");
   else if(S_ISDIR(m))
       strcpy(str,"d");
   else if(S_ISCHR(m))
       strcpy(str,"c");
   else if(S_ISBLK(m))
       strcpy(str,"b");
   else if(S_ISFIFO(m))
       strcpy(str,"f");
   else if(S_ISLNK(m))
       strcpy(str,"l");
   else if(S_ISSOCK(m))
       strcpy(str,"n");
   strcat(str,m&S_IRUSR?"r":"-");
   strcat(str,m&S_IWUSR?"w":"-");
   strcat(str,m&S_IXUSR?"x":"-");
   strcat(str,m&S_IRGRP?"r":"-");
   strcat(str,m&S_IWGRP?"w":"-");
   strcat(str,m&S_IXGRP?"x":"-");
   strcat(str,m&S_IROTH?"r":"-");
   strcat(str,m&S_IWOTH?"w":"-");
   strcat(str,m&S_IXOTH?"x":"-");
   return str;
}

int ls()
{
   DIR* dp=opendir(".");
   if(NULL == dp)
   {
       perror("opendir");
       return -1;
   }
   struct dirent* de=readdir(dp);
   for(;de;de=readdir(dp))
   {
       if('.'==de->d_name[0]) continue;
       struct stat s;
       int ret = lstat(de->d_name,&s);
       if(0 > ret)
       {
           perror("stat");
           return -1;
       }
       char str[11] = {};
       printf("%s ",get_mode(s.st_mode,str));
       printf("%5lld ",s.st_size);
       printf("%s\t",de->d_name);
       printf("\n");
   }
   closedir(dp);
}