#include<stdio.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<dirent.h>
#include<string.h>
#include<sys/types.h>
#include<pwd.h>
#include<grp.h>
void mode_to_letters(int mode,char str[]);
void do_ls(char dirname[]);
void show_stat_info(char *fname,struct stat *buf);
char *uid_to_name(uid_t uid);
char *gid_to_name(gid_t gid);
int main(int ac,char *av[])
{
if(ac==1)
do_ls(".");
else
while(ac--)
{
printf("%s:\n",*++av);
do_ls(*av);
}
}
void do_ls(char dirname[])
{
DIR *drip; //the directory
struct dirent *direntp; //each entry
struct stat info;
if((drip=opendir(dirname))==NULL)
fprintf(stderr,"ls2:cannot open %s\n",dirname);
else
{
while((direntp=readdir(drip))!=NULL)
if(stat(direntp->d_name,&info)!=-1)
{
show_stat_info(direntp->d_name,&info);
}
else
perror(direntp->d_name);
closedir(drip);
}
}
void show_stat_info(char *fname,struct stat *buf)
{
char str[11];
mode_to_letters(buf->st_mode,str);
printf("%10s",str);
//printf(" mode:%o ",buf->st_mode);
printf("%3d ",buf->st_nlink);
printf("%-6s",uid_to_name(buf->st_uid));
printf("%-7s",gid_to_name(buf->st_gid));
printf("%8ld ",buf->st_size);
printf("%12.12s ",4+ctime(&(buf->st_mtime)));
printf("%s\n",fname);
}
/*
* This function takes a mode value and a char array
* and puts into the char array the file type and the
* nine letters that correspond to the bits in mode.
* NOTE:It doesn't code setuid,setgid,and sticky
* codes
*/
void mode_to_letters(int mode,char str[])
{
strcpy(str,"----------"); /*default=no perms*/
if(S_ISDIR(mode)) str[0]='d'; /*directory*/
if(S_ISCHR(mode)) str[0]='c'; /*char device*/
if(S_ISBLK(mode)) str[0]='b'; /*block device*/
if(S_ISREG(mode)) str[0]='-'; /*regular device*/
if(mode & S_IRUSR) str[1]='r'; /*the privilege of the owner*/
if(mode & S_IWUSR) str[2]='w';
if(mode & S_IXUSR) str[3]='x';
if(mode & S_IRGRP) str[4]='r'; /*the privilege of the group*/
if(mode & S_IWGRP) str[5]='w';
if(mode & S_IXGRP) str[6]='x';
if(mode & S_IROTH) str[7]='r'; /*the privilege of others*/
if(mode & S_IWOTH) str[8]='w';
if(mode & S_IXOTH) str[9]='x';
}
/*transit user id to user name*/
char *uid_to_name(uid_t uid)
{
struct passwd *getpwuid(),*ptr;
static char numstr[10];
if((ptr=getpwuid(uid))==NULL)
{
sprintf(numstr,"%d",uid);
return numstr;
}
else
return ptr->pw_name;
}
/*transit gruop id to group name*/
char *gid_to_name(gid_t gid)
{
struct group *getgrgid(),*grd_ptr;
static char numstr[10];
if((grd_ptr=getgrgid(gid))==NULL)
{
sprintf(numstr,"%d",gid);
return numstr;
}
else
return grd_ptr->gr_name;
}
