c program shell input through php - php

Question

I am trying to develop something that could execute c programs through php, using system() , exec() commands, and it does execute the c program, but the problem here is - If a c program contains scanf() statement, the system() doesn't ask for user input on a php webpage.
I'm pretty not sure that it can be done.
<?php
$content = $_POST['content']; //Getting the code from web form
$file = fopen("code.cpp","w"); //Opening a file in write mode
fwrite($file,$content); //Store the code to file code.cpp
$my_file = 'code.cpp';
system("gcc {$my_file} 2> error.txt"); //Compile a c program and log the errors to error.txt
$error = file_get_contents("error.txt"); //Getting contents of error.txt to a variable
if($error=='')
system("./a.out"); //Executing the c program
else{
$fp = fopen("error.txt","r");
while (! feof($fp)){ //Printing the output line by line
echo fgets($fp). "<br />";
}
}
fclose($content);
unlink('a.out');
unlink('code.cpp');
?>
I've hosted the php page on a gcc installed ubuntu machine. Any help would be appreciated. Thanks.

Answer 1

Setting aside the security issues...
Create an input file form the data from $_POST.
Redirect the content of the file while executing the progrm.
Here's the updated PHP file.
<?php
$content = $_POST['content']; //Getting the code from web form
$file = fopen("code.cpp","w"); //Opening a file in write mode
fwrite($file,$content); //Store the code to file code.cpp
fclose($file);
$inputData = $_POST['inputData']; //Getting the data from web form
$file = fopen("input.txt","w"); //Opening a file in write mode
fwrite($file,$inputData); //Store the data to file input.txt
fclose($file);
$my_file = 'code.cpp';
system("gcc {$my_file} 2> error.txt");
$error = file_get_contents("error.txt");
if($error=='')
system("./a.out < input.txt");
else {
$fp = fopen("error.txt","r");
while (! feof($fp)){
echo fgets($fp). "<br />";
}
}
unlink('a.out');
unlink('input.txt');
unlink('code.cpp');
?>