Simulation Of UNIX Command - LS

#include<stdio.h>

#include<string.h>

#include<stdlib.h>

#include<error.h>

#include<dirent.h>

#include<sys/stat.h>

#include<syslog.h>

#include<unistd.h>

#include<linux/unistd.h>

#define MAX_NO_FILE 40

#define PATH_LEN 200

#define MAXSIZE 100

#define MAXLENGTH 40

char cur_dir[MAXSIZE*4];

char file_list[MAX_NO_FILE][MAXLENGTH];

int listdir(char *dir_path)

{

DIR *dir;

struct dirent* entry;

char entry_path[400+1],back[MAXSIZE];

size_t path_len;

int count=0;

char temp[MAXSIZE*4];

chdir(dir_path);

getcwd(dir_path,MAXSIZE);

getcwd(cur_dir,MAXSIZE);

memset(entry_path,0,sizeof(entry_path));

snprintf(entry_path,400+1,"%s",dir_path);

path_len=strlen(dir_path);

if(entry_path[path_len-1]!='/')

{

entry_path[path_len]='/';

entry_path[path_len+1]='\0';

++path_len;

}

dir=opendir(dir_path);

strcpy(back,dir_path);

strcat(back,"/.../");

while((entry=readdir(dir))!=NULL)

{

strncpy(entry_path+path_len,entry->d_name,sizeof(entry_path)-path_len);

syslog(LOG_INFO,"%s:%s",entry->d_name,entry_path);

if(strcmp(entry->d_name,".")!=0)

{

if(!((entry->d_name[0]=='.')&&(entry->d_name[1]!='.')))

{

if(strcmp(entry->d_name,"..")!=0)

{

snprintf(file_list[count],MAXLENGTH,"%s",entry->d_name);

count++;

if(count>=MAX_NO_FILE)

break;

}

}

}

}

closedir(dir);

return count;

}

int isdir(char *path)

{

char temp[MAXSIZE*4];

struct stat st;

snprintf(temp,MAXSIZE*4,"%s",path);

stat(temp,&st);

if(S_ISDIR(st.st_mode))

return 0;

else

return 1;

}

int main(int argc,char *argv[])

{

int cnt,i;

char path_to_list[PATH_LEN];

if(argc!=2)

printf("usage:myls<path_to_dir>\n");

snprintf(path_to_list,PATH_LEN,"%s",argv[1]);

printf("the files in the directory\n");

if(isdir(path_to_list)==0)

{

cnt=listdir(path_to_list);

for(i=0;i<cnt;i++)

printf("%s\n",file_list[i]);

}

else

printf("%s\n",path_to_list);

return 0;

}

Output:

          

     

[telnet29@linux ~]$ ./a.out /

the files in the directory

misc

boot

opt

mnt

srv

net

lost+found

lib

etc

sbin

proc

tmp