#define _GNU_SOURCE

#include <dirent.h>

#include <fcntl.h>

#include <stdio.h>

#include <unistd.h>

#include <stdlib.h>

#include <sys/stat.h>

#include <sys/syscall.h>

#include <sys/types.h>

#define handle_error(msg) \

do { perror(msg); exit(EXIT_FAILURE); } while (0)

struct linux_dirent {

};

#define BUF_SIZE 1024

int len(char *s)

{

int i;

for(i=0;s[i];i++)

;

return i;

}

int contains(char *s,char c)

{

int i;

for(i=0;s[i];i++)

{

if(s[i]==c)

return 1;

}

return 0;

}

int compare(char *s1, char *s2)

{

int i;

if(len(s1)!=len(s2))

return 0;

for(i=0;s1[i]&&s2[i];i++)

if(s1[i]!=s2[i])

return 0;

return 1;

}

void assign(char *tmp, char *file)

{

int i;

for(i=0;file[i];i++)

tmp[i]=file[i];

tmp[i]='\0';

}

void concat(char *s1,char *s2)

{

int j,i=0;

for(i=0;s1[i];i++)

;

for(j=0;s2[j];j++)

{

s1[j+i]=s2[j];

}

s1[j+i]='\0';

}

char str[50];

int k=0;

void tostring(int n)

{

k=0;

char str1[50];

int z=0;

while(n)

{

str1[z++]=n%10+'0';

n/=10;

}

int i;

for(i=z-1;i>=0;i--)

str[k++]=str1[i];

str[k]='\0';

}

void printinteger(int n)

{

tostring(n);

if(n==0)

{

str[0]='0';

str[1]='\0';

}

write(1, str,len(str)+1);

}

void printdatemodified(long long int secs)

{

long long int tempdays=24*60*60,days=0;

secs+=5*60*60+30*60;

int year=1970;

while(secs>tempdays)

{

days++;

if((days%365==0&&year%4)||(days%366==0))

{

year++;

days=0;

}

secs-=24*60*60;

//tempdays+=24*60*60;

}

int monthdays[]={0,31,28,31,30,31,30,31,31,30,31,30,31};

char *months[]={"Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"};

int i;

if(year%4==0)monthdays[2]++;

for(i=1;i<=12;i++)

{

if(days<monthdays[i])

break;

else

days-=monthdays[i];

}

int hours=0,mins=0;

while(secs>60)

{

if(secs>3600)

{

secs-=3600;

hours++;

}

else if(secs>60)

{

secs-=60;

mins++;

}

}

write(1,months[i-1],4);

write(1," ",1);

printinteger(days+1);

write(1," ",1);

if(hours/10==0)

printinteger(0);

printinteger(hours);

write(1,":",1);

if(mins/10==0)

printinteger(0);

printinteger(mins);

write(1," ",1);

//printf("%lld %d %d %d %lld\n",days,hours,mins,i,secs);

}

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

{

int size,tmpdec,i,fd, nread, fp, ntemp, tmpi,colons, uid,tmpflag;

double tmpsize;

long long int giga,mega,kilo;

giga=1024*1024*1024;

mega=1024*1024;

kilo=1024;

char buf[BUF_SIZE];

char user[50];

char buffer[50000],linkval[500];

char line[1000];

struct linux_dirent *d;

int bpos,isalink;

int flag=0,hasfile=0;

char d_type;

int l=0,a=0,h=0;

struct stat fileStat,tmpStat;

char file[100],tmpfile[100];

if(argc==2||argc==3)

{

if(compare(argv[1],"-l")||compare(argv[1],"-a")||compare(argv[1],"-h")||compare(argv[1],"-lah")||compare(argv[1],"-lha")||compare(argv[1],"-ahl")||compare(argv[1],"-alh")||compare(argv[1],"-hla")||compare(argv[1],"-hal")||compare(argv[1],"-la")||compare(argv[1],"-ah")||compare(argv[1],"-hl")||compare(argv[1],"-al")||compare(argv[1],"-ha")||compare(argv[1],"-lh"))

{

flag=1;

if(argc>2)

hasfile=1;

if(contains(argv[1],'l'))

l=1;

if(contains(argv[1],'a'))

{

if(l==0)

flag=0;

if(argc==3)

hasfile=1;

a=1;

}

if(contains(argv[1],'h'))

{

h=1;

if(l==0)

flag=0;

if(argc==3)

hasfile=1;

}

}

else if(argc==2)

hasfile=1;

}

if(argc==3)

{

if(compare(argv[2],"-l")||compare(argv[2],"-a")||compare(argv[2],"-h")||compare(argv[2],"-lah")||compare(argv[2],"-lha")||compare(argv[2],"-ahl")||compare(argv[2],"-alh")||compare(argv[2],"-hla")||compare(argv[2],"-hal")||compare(argv[2],"-la")||compare(argv[2],"-ah")||compare(argv[2],"-hl")||compare(argv[2],"-al")||compare(argv[2],"-ha")||compare(argv[2],"-lh"))

{

flag=2;

hasfile=1;

if(contains(argv[2],'l'))

l=1;

if(contains(argv[2],'a'))

{

a=1;

if(l==0)

flag=0;

}

if(contains(argv[2],'h'))

{

h=1;

if(l==0)

flag=0;

}

}

}

// printf("%d %d %d %d %d %d\n" ,l,a,h,hasfile,flag, argc);

if((!flag&&a&!l)||(!flag&&h&!l)||!a&!l&!h||(!flag&&a&h))

{

if(argc>1)

{

file[0]='\0';

if(!a&&!h)

{

fd = open(argv[1], O_RDONLY | O_DIRECTORY);

concat(file,argv[1]);

//printf("%s",file);

}

else if(a|h)

{

if(hasfile)

{

if(compare(argv[1],"-a")||compare(argv[1],"-h")||compare(argv[1],"-ah")||compare(argv[1],"-ha"))

{

fd = open(argv[2], O_RDONLY | O_DIRECTORY);

concat(file,argv[2]);

}

else if(compare(argv[2],"-a")||compare(argv[2],"-h")||compare(argv[2],"-ah")||compare(argv[2],"-ha"))

{

fd = open(argv[1], O_RDONLY | O_DIRECTORY);

concat(file,argv[1]);

}

//fd = open(".", O_RDONLY | O_DIRECTORY);

}

else

{

fd = open(".", O_RDONLY | O_DIRECTORY);

file[0]='.';

file[1]='\0';

}

}

}

else

{

fd = open(".", O_RDONLY | O_DIRECTORY);

file[0]='.';

file[1]='\0';

}

if (fd == -1)

handle_error("open");

for ( ; ; )

{

nread = syscall(SYS_getdents, fd, buf, BUF_SIZE);

if (nread == -1)

handle_error("getdents");

if (nread == 0)

break;

for (bpos = 0; bpos < nread;) {

isalink=0;

d = (struct linux_dirent *) (buf + bpos);

d_type = *(buf + bpos + d->d_reclen - 1);

if(d->d_name[0]=='.'&&!a)

{

bpos += d->d_reclen;

continue;

}

tmpfile[0]='.';

tmpfile[1]='\0';

assign(tmpfile,file);

concat(tmpfile,"/");

//printf("");

concat(tmpfile,d->d_name);

if(lstat(tmpfile,&fileStat) < 0)

return -1;

if(!a)

{

if(d->d_name[0]!='.')

{

if(S_ISDIR(fileStat.st_mode))

write(1,"\x1b[1;34m",8);

else if(d_type==DT_LNK)

write(1,"\x1b[1;36m",8);

else if(fileStat.st_mode & S_IXUSR)

write(1,"\x1b[1;32m",8);

write(1,d->d_name,len(d->d_name)+1);

if(S_ISDIR(fileStat.st_mode))

write(1,"\x1b[0m",5);

else if(d_type==DT_LNK)

write(1,"\x1b[0m",5);

else if(fileStat.st_mode & S_IXUSR)

write(1,"\x1b[0m",5);

write(1,"\t",2);

}

}

else

{

if(S_ISDIR(fileStat.st_mode))

write(1,"\x1b[1;34m",8);

else if(d_type==DT_LNK)

write(1,"\x1b[1;36m",8);

else if(fileStat.st_mode & S_IXUSR)

write(1,"\x1b[1;32m",8);

write(1,d->d_name,len(d->d_name)+1);

if(S_ISDIR(fileStat.st_mode))

write(1,"\x1b[0m",5);

else if(d_type==DT_LNK)

write(1,"\x1b[0m",5);

else if(fileStat.st_mode & S_IXUSR)

write(1,"\x1b[1;32m",8);

write(1,"\t",2);

// write(1,d->d_name,len(d->d_name)+1);

write(1,"\t",2);

}

bpos += d->d_reclen;

}

}

write(1,"\n",2);

exit(EXIT_SUCCESS);

}

else if(flag==1)

{

if(hasfile)

{

fd = open(argv[2], O_RDONLY | O_DIRECTORY);

file[0]='\0';

concat(file,argv[2]);

}

else

{

fd = open(".", O_RDONLY | O_DIRECTORY);

file[0]='.';

file[1]='\0';

}

if (fd == -1)

handle_error("open");

}

else

{

fd = open(argv[1], O_RDONLY | O_DIRECTORY);

file[0]='\0';

concat(file,argv[1]);

}

if (fd == -1)

handle_error("open");

for ( ; ; )

{

nread = syscall(SYS_getdents, fd, buf, BUF_SIZE);

if (nread == -1)

handle_error("getdents");

if (nread == 0)

break;

//printf("%d",nread);

for (bpos = 0; bpos < nread;)

{

k=0;

isalink=0;

d = (struct linux_dirent *) (buf + bpos);

d_type = *(buf + bpos + d->d_reclen - 1);

if(d->d_name[0]=='.' && !a)

{

bpos += d->d_reclen;

continue;

}

//printf("%s\t",d->d_name);

tmpfile[0]='\0';

assign(tmpfile,file);

concat(tmpfile,"/");

concat(tmpfile,d->d_name);

if(lstat(tmpfile,&fileStat) < 0)

return 1;

if(S_ISDIR(fileStat.st_mode))

write(1,"d",2);

else

{

if(d_type==DT_LNK)

{

isalink=1;

write(1,"l",2);

}

else

write(1,"-",2);

}

// write(1, (S_ISDIR(fileStat.st_mode)) ? "d" : (S_ISLNK(fileStat.st_mode)?"l":"-"), 2);

write(1, (fileStat.st_mode & S_IRUSR) ? "r" : "-", 2);

write(1, (fileStat.st_mode & S_IWUSR) ? "w" : "-", 2);

write(1, (fileStat.st_mode & S_IXUSR) ? "x" : "-", 2);

write(1, (fileStat.st_mode & S_IRGRP) ? "r" : "-", 2);

write(1, (fileStat.st_mode & S_IWGRP) ? "w" : "-", 2);

write(1, (fileStat.st_mode & S_IXGRP) ? "x" : "-", 2);

write(1, (fileStat.st_mode & S_IROTH) ? "r" : "-", 2);

write(1, (fileStat.st_mode & S_IWOTH) ? "w" : "-", 2);

write(1, (fileStat.st_mode & S_IXOTH) ? "x" : "-", 2);

write(1," ",2);

if(!isalink)

printinteger(fileStat.st_nlink);

else

write(1,"1",2);

write(1,"\t",2);

//printinteger(fileStat.st_uid);

//write(1,"\t",2);

{

fp=open("/etc/passwd",O_RDONLY);

tmpi=0;colons=0;tmpflag=0;uid=0;

while(ntemp=read(fp, buffer, 1))

{

if(buffer[0]=='\n')

{

colons=0;

tmpflag=0;

uid=0;

tmpi=0;

line[0]='\0';

continue;

}

line[tmpi++]=buffer[0];

if(buffer[0]==':')

colons++;

if(colons==3&&tmpflag)

{

tmpflag=0;

if(uid==fileStat.st_uid)

break;

}

if(tmpflag)

{

uid=uid*10+buffer[0]-'0';

}

if(colons==2)

tmpflag=1;

}

line[tmpi]='\0';

tmpi=0;

for(i=0;line[i];i++)

{

if(line[i]==':')

break;

else

user[tmpi++]=line[i];

}

user[tmpi]='\0';

//printinteger(uid);

write(1, user, len(user)+1);

}

write(1,"\t",2);

{

fp=open("/etc/group",O_RDONLY);

tmpi=0;colons=0;tmpflag=0;uid=0;

while(ntemp=read(fp, buffer, 1))

{

if(buffer[0]=='\n')

{

colons=0;

tmpflag=0;

uid=0;

tmpi=0;

line[0]='\0';

continue;

}

line[tmpi++]=buffer[0];

if(buffer[0]==':')

colons++;

if(colons==3&&tmpflag)

{

tmpflag=0;

if(uid==fileStat.st_gid)

break;

}

if(tmpflag)

{

uid=uid*10+buffer[0]-'0';

}

if(colons==2)

tmpflag=1;

}

line[tmpi]='\0';

tmpi=0;

for(i=0;line[i];i++)

{

if(line[i]==':')

break;

else

user[tmpi++]=line[i];

}

user[tmpi]='\0';

write(1, user, len(user)+1);

}

write(1,"\t",2);

if(h)

{

tmpsize=fileStat.st_size;

size=(int)(tmpsize);

if(size/giga)

{

if(size/giga>1024)

{

printinteger((int)((tmpsize/giga)/1024));

tmpdec=((int)(10*((tmpsize/giga)/1024)))%10;

write(1,".",2);

//printf("*%d*",tmpdec);

printinteger(tmpdec);

write(1, "T", 2);

}

else

{

printinteger((int)(tmpsize/giga));

tmpdec=((int)((10*(tmpsize/giga))))%10;

write(1,".",2);

//printf("*%d*",tmpdec);

printinteger(tmpdec);

write(1, "G", 2);

}

}

else if(size/mega)

{

printinteger((int)(tmpsize/mega));

tmpdec=((int)(10*(tmpsize/mega)))%10;

write(1,".",2);

// printf("*%d*",tmpdec);

printinteger(tmpdec);

write(1, "M", 2);

}

else if(size/kilo)

{

printinteger((int)(tmpsize/kilo));

tmpdec=((int)(10*(tmpsize/kilo)))%10;

write(1,".",2);

//printf("*%d*",tmpdec);

printinteger(tmpdec);

write(1, "K", 2);

}

else

{

printinteger(size);

}

}

else

printinteger(fileStat.st_size);

write(1, "\t", 2);

printdatemodified(fileStat.st_mtime);

if(S_ISDIR(fileStat.st_mode))

write(1,"\x1b[1;34m",8);

else if(isalink)

write(1,"\x1b[1;36m",8);

else if(fileStat.st_mode & S_IXUSR)

write(1,"\x1b[1;32m",8);

write(1,d->d_name,len(d->d_name)+1);

if(S_ISDIR(fileStat.st_mode))

write(1,"\x1b[0m",5);

else if(isalink)

{

write(1,"\x1b[0m",5);

write(1, " -> ",4);

readlink(tmpfile,linkval,500);

write(1,"\x1b[1;34m",8);

write(1,linkval,len(linkval));

write(1,"\x1b[0m",5);

}

else if(fileStat.st_mode & S_IXUSR)

write(1,"\x1b[0m",5);

write(1,"\n",2);

bpos += d->d_reclen;

}

}

exit(EXIT_SUCCESS);

}