From 894772fd48cf0ede4a1ce4a90aa7694674806200 Mon Sep 17 00:00:00 2001
From: bnewbold <bnewbold@robocracy.org>
Date: Mon, 3 Oct 2016 20:06:31 -0700
Subject: basic file descriptor passing

---
 src/main.rs | 52 ++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 42 insertions(+), 10 deletions(-)

(limited to 'src')

diff --git a/src/main.rs b/src/main.rs
index d87f037..d4221dc 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -19,28 +19,45 @@
 extern crate getopts;
 extern crate log;
 extern crate env_logger;
+extern crate nix;
 
 use std::env;
 use std::u64;
 use std::str::FromStr;
-use std::{time, thread};
 use std::process::exit;
 use std::process::Command;
+use std::process::Child;
+use std::net::SocketAddr;
+use std::net::TcpListener;
+use std::net::ToSocketAddrs;
 use getopts::Options;
 
-fn run(prog: Vec<String>, number: u64) {
+use std::os::unix::io::IntoRawFd;
 
+fn run(binds: Vec<TcpListener>, mut prog: Command, number: u64) {
 
+    prog.env("EINHORN_FD_COUNT", binds.len().to_string());
+    // This iterator destroys the TcpListeners
+    for (i, b) in binds.into_iter().enumerate() {
+        let orig_fd = b.into_raw_fd();
+        // Duplicate, which also clears the CLOEXEC flag
+        //let fd = nix::fcntl::fcntl(nix::fcntl::FcntlArg::F_DUPFD(orig_fd)).unwrap();
+        let fd = nix::unistd::dup(orig_fd).unwrap();
+        println!("fd={} FD_CLOEXEC={}", fd, nix::fcntl::fcntl(fd, nix::fcntl::FcntlArg::F_GETFD).unwrap());
+        prog.env(format!("EINHORN_FD_{}", i), fd.to_string());
+        // NB: is fd getting destroyed here?
+    }
+
+    let mut children: Vec<Child> = vec![];
     for _ in 0..number {
         println!("Running!");
-        Command::new(&prog[0])
-                .args(&prog[1..])
-                .spawn()
-                .expect("command failed");
+        children.push(prog.spawn().expect("error spawning"));
     }
 
-    println!("Sleeping for 1sec");
-    thread::sleep(time::Duration::from_secs(1));
+    println!("Waiting for all children to die");
+    for mut c in children {
+        c.wait().unwrap();
+    }
 }
 
 fn print_usage(opts: Options) {
@@ -54,6 +71,7 @@ fn main() {
     let args: Vec<String> = env::args().collect();
 
     let mut opts = Options::new();
+    opts.parsing_style(getopts::ParsingStyle::StopAtFirstFree);
     opts.optflag("h", "help", "print this help menu");
     opts.optflag("v", "verbose", "more debugging messages");
     opts.optopt("n", "number", "how many program copies to spawn", "COUNT");
@@ -70,10 +88,16 @@ fn main() {
     }
 
     let number: u64 = match matches.opt_str("number") {
-        Some(n) => u64::from_str(&n).unwrap(),
+        Some(n) => u64::from_str(&n).expect("number arg should be an integer"),
         None => 1
     };
 
+    let sock_addrs: Vec<SocketAddr> = matches.opt_strs("bind").iter().map(|b| {
+        //let sa: SocketAddr = b.to_socket_addrs().unwrap().next().unwrap();
+        //sa
+        b.to_socket_addrs().unwrap().next().unwrap()
+    }).collect();
+
     let program_and_args = if !matches.free.is_empty() {
         matches.free
     } else {
@@ -88,5 +112,13 @@ fn main() {
     }
     builder.init().unwrap();
 
-    run(program_and_args, number);
+    let binds: Vec<TcpListener> = sock_addrs.iter().map(|sa| {
+        TcpListener::bind(sa).unwrap()
+    }).collect();
+
+    let mut prog = Command::new(&program_and_args[0]);
+    prog.args(&program_and_args[1..]);
+
+    run(binds, prog, number);
+    exit(0);
 }
-- 
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