Added pipe functionality.

hw6/task1/src/main.rs

@@ -3,7 +3,7 @@ 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 nix::sys::wait::WaitStatus;
 use nix::unistd::ForkResult::{Child, Parent};
@@ -12,25 +12,32 @@ fn main() {
 
  let arguments: Vec<String> = args().collect();
 
-    if arguments.len() != 0 {
-   
+    if arguments.len() > 2 {
+        let (reader, writer) = pipe().unwrap();
+        let msg = "hello from parent";
+        let pid = fork();
+        match pid {
+            Ok(Child) => {
+                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);
+            }
 
-    let pid = fork();
-    match pid {
-        Ok(Child) => {
-            println!("hello, I am child (pid:{})", getpid());
-        }
+            Ok(Parent { child }) => {
+
+                println!("sending to child with pid:{}", child);
+                write(writer, msg.as_bytes()).unwrap();
 
-        Ok(Parent { child }) => {
-            if let Ok(ws) = wait() {
-                if let WaitStatus::Exited(child_pid, exit_code) = ws {
-                
+                if let Ok(ws) = wait() {
+                    if let WaitStatus::Exited(child_pid, exit_code) = ws {
+                        println!("Parent exits");
+                    }
                 }
             }
-        }
 
-        Err(_) => {}
-    }
+            Err(_) => {}
+        }