@@ -1,89 +1,83 @@
```
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <string.h>
#include <unistd.h>
void print_help (char * prog_name ) {
printf ("Usage: %s [-n] DEVNAME COMMAND\n" , prog_name );
printf ("Usage: '-n' is an optional argument if you want to push a new line at the end of the text\n" );
printf ("Usage: Will require 'sudo' to run if the executable is not setuid root\n" );
exit (1 );
}
int main (int argc , char * argv []) {
char * cmd , * nl = "\n" ;
int i , fd ;
int devno , commandno , newline ;
int mem_len ;
devno = 1 ; commandno = 2 ; newline = 0 ;
if (argc < 3 ) {
print_help (argv [0 ]);
}
if (argc > 3 && argv [1 ][0 ] == '-' && argv [1 ][1 ] == 'n' ) {
devno = 2 ; commandno = 3 ; newline = 1 ;
} else if (argc > 3 && argv [1 ][0 ] == '-' && argv [1 ][1 ] != 'n' ) {
printf ("Invalid Option\n" );
print_help (argv [0 ]);
}
fd = open (argv [devno ],O_RDWR );
if (fd == -1 ) {
perror ("open DEVICE" );
exit (1 );
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <string.h>
#include <unistd.h>
void print_help (char * prog_name ) {
printf ("Usage: %s [-n] DEVNAME COMMAND\n" , prog_name );
printf ("Usage: '-n' is an optional argument if you want to push a new line at the end of the text\n" );
printf ("Usage: Will require 'sudo' to run if the executable is not setuid root\n" );
exit (1 );
}
mem_len = 0 ;
for ( i = commandno ; i < argc ; i ++ ) {
mem_len += strlen (argv [i ]) + 2 ;
if ( i > commandno ) {
cmd = (char * )realloc ((void * )cmd , mem_len );
} else { //i == commandno
cmd = (char * )malloc (mem_len );
int main (int argc , char * argv []) {
char * cmd , * nl = "\n" ;
int i , fd ;
int devno , commandno , newline ;
int mem_len ;
devno = 1 ; commandno = 2 ; newline = 0 ;
if (argc < 3 ) {
print_help (argv [0 ]);
}
strcat (cmd , argv [i ]);
strcat (cmd , " " );
if (argc > 3 && argv [1 ][0 ] == '-' && argv [1 ][1 ] == 'n' ) {
devno = 2 ; commandno = 3 ; newline = 1 ;
} else if (argc > 3 && argv [1 ][0 ] == '-' && argv [1 ][1 ] != 'n' ) {
printf ("Invalid Option\n" );
print_help (argv [0 ]);
}
fd = open (argv [devno ],O_RDWR );
if (fd == -1 ) {
perror ("open DEVICE" );
exit (1 );
}
mem_len = 0 ;
for ( i = commandno ; i < argc ; i ++ ) {
mem_len += strlen (argv [i ]) + 2 ;
if ( i > commandno ) {
cmd = (char * )realloc ((void * )cmd , mem_len );
} else { //i == commandno
cmd = (char * )malloc (mem_len );
}
strcat (cmd , argv [i ]);
strcat (cmd , " " );
}
if (newline == 0 )
usleep (225000 );
for (i = 0 ; cmd [i ]; i ++ )
ioctl (fd , TIOCSTI , cmd + i );
if (newline == 1 )
ioctl (fd , TIOCSTI , nl );
close (fd );
free ((void * )cmd );
exit (0 );
}
if (newline == 0 )
usleep (225000 );
for (i = 0 ; cmd [i ]; i ++ )
ioctl (fd , TIOCSTI , cmd + i );
if (newline == 1 )
ioctl (fd , TIOCSTI , nl );
close (fd );
free ((void * )cmd );
exit (0 );
}
```
Copy the above code to some C file (For eg . ` ttyecho .c ` ). Run the following command in the directory you have created the C file in to compile the code .
Copy the above code to some C file (For eg . ttyecho .c ). Run the following command in the directory you have created the C file in to compile the code .
` make ttyecho `
make ttyecho
Copy this file to the bin directory under your Home Directory . Create the directory if it doesn ’t exist . Its a good practice to keep all custom binaries /executables in this bin directory .
Start another terminal or switch to any other open terminal that you wish to control and execute the command tty . You can see a sample output below .
```
@~$ tty
/dev /pts /5
```
@~$ tty
/dev /pts /5
Now to execute a command on ` /dev /pts /5 ` , run the following command in the controlling /original terminal .
Now to execute a command on /dev /pts /5 , run the following command in the controlling /original terminal .
` sudo ttyecho - n /dev /pts /5 ls `
sudo ttyecho - n /dev /pts /5 ls
You will see that the ` ls ` command is executed in ` /dev /pts /5 ` . The ` - n ` option makes ` ttyecho ` send a newline after the command , so that the command gets executed and not just inserted . This utility can infact be used to send any data to other terminals For eg , you could open vim in `/dev /pts /5 ` and then run the following command in the controlling terminal to cause vim to exit in `/dev /pts /5 `.
You will see that the ls command is executed in /dev /pts /5. The - n option makes ttyecho send a newline after the command , so that the command gets executed and not just inserted . This utility can infact be used to send any data to other terminals For eg , you could open vim in `/dev /pts /5 ` and then run the following command in the controlling terminal to cause vim to exit in `/dev /pts /5 `.
` sudo ttyecho - n /dev /pts /5 :q `
sudo ttyecho - n /dev /pts /5 :q
To avoid using sudo all the time , so that the command is easily scriptable , change the owners /permissions of this executable using the following commands .
== NB :Setting the setuid bit can become a security risk .
```
sudo chown root :root ttyecho
sudo chmod u + s ttyecho
```
sudo chown root :root ttyecho
sudo chmod u + s ttyecho
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