In Turtle, how do I take stdout from a program, process it, and then supply something to stdin?

Question

I am currently playing with format string attacks in C. I have a toy program that prints (to stdout) the address of a variable that I want to access, then accepts a line from stdin and printfs it..

Using Turtle, I'd like to be able to:

• execute the program
• parse the first few lines of stdout to retrieve the address
• using the address, craft a format string for printf (I know how to do this bit)
• write the attack string to stdin

However, I can't see how to do this. Using a function like inshell :: Text -> Shell Line -> Shell Line, I can supply some lines to stdin and get back a stream from stdout. However, I don't know how to inject new lines to stdin after having read a couple of lines from stdout.

Answer 1

If your goal is to test your program which performs IO you can use shelltestrunner (project written in Haskell) if you want to test I/O scenarios for every project (non necessarily written in Haskell).