Merge branch 'hw6' of https://github.com/themultiplexer/bsys-ws17-grp11 into hw6

hw6/task1/src/main.rs

@@ -3,8 +3,9 @@ use std::process;
 
 extern crate nix;
 
-use nix::unistd::{fork, getpid};
+use nix::unistd::{fork, getpid, pipe, read, write};
 use nix::sys::wait::wait;
+use std::str;
 use nix::sys::wait::WaitStatus;
 use nix::unistd::ForkResult::{Child, Parent};
 
@@ -14,16 +15,26 @@ fn main() {
 
     if arguments.len() > 2 {
 
-
+        let (reader, writer) = pipe().unwrap();
+        let msg = "hello from parent";
         let pid = fork();
         match pid {
             Ok(Child) => {
-                println!("hello, I am child (pid:{})", getpid());
+                let mut read_buf = [0u8; 32];
+                let bytes_read = read(reader, &mut read_buf).unwrap();
+                let msg_received = str::from_utf8(&read_buf[0..bytes_read]).unwrap();
+                println!("{} received from parent:{:?}", getpid(), msg_received);
             }
 
             Ok(Parent { child }) => {
+
+                println!("sending to child with pid:{}", child);
+                write(writer, msg.as_bytes()).unwrap();
+
                 if let Ok(ws) = wait() {
-                    if let WaitStatus::Exited(child_pid, exit_code) = ws {}
+                    if let WaitStatus::Exited(child_pid, exit_code) = ws {
+                        println!("Parent exits");
+                    }
                 }
             }