Detecting when a child process is waiting for input

Question

I\'m writing a Python program for running user-uploaded arbitrary (and thus, at the worst case, unsafe, erroneous and crashing) code on a Linux server. The security question

Answer 1

Instead of trying to detect when the child process is waiting for an input, you can use the linux script command. From the man page for script:

The script utility makes a typescript of everything printed on your terminal.

You can use it like this if you were using it on a terminal:

$ script -q  

So in Python you can try giving this command to the Popen routine instead of just .

Edit: I made the following program:

#include 
int main() {
    int i;
    scanf("%d", &i);
    printf("i + 1 = %d\n", i+1);
}

and then ran it as follows:

$ echo 9 > infile
$ script -q output ./a.out < infile
$ cat output
9
i + 1 = 10

So I think it can be done in Python this way instead of using the stdout, stderr and stdin flags of Popen.