parse the datagram payload and fork lua on the file

src/main.rs

@@ -13,27 +13,66 @@ use std::{
 use std::os::unix::net::{
     UnixDatagram,
     SocketAncillary,
-    AncillaryData
+    AncillaryData,
+    SocketAddr
+
 };
 
 use libc::WEXITSTATUS;
 use fork::{Fork, fork, waitpid};
 
-// if we use SCM_RIGHTS to pass fds from client, we also need to
-// write the client as we can't do that with socat
+fn fork_lua(lua : &Lua, args: Vec<String>, fds: Vec<i32>) -> Option<i32> {
+    let pathname = &args[0];
 
-fn run_lua(lua : &Lua, path : &Path) {
-    let chunk = lua.load(path);
-    match chunk.exec() {
-	Ok(()) => { println!("lua returned ok"); },
-	Err(e) => {
-	    println!("lua error {:?}", e);
-	    exit(1);
+    let path = Path::new(pathname);
+    match fork() {
+	Ok(Fork::Parent(pid)) => Some(pid),
+	Ok(Fork::Child) => {
+	    for (i, fd) in fds.iter().enumerate() {
+		unsafe { libc::dup2(*fd, i.try_into().unwrap()); }
+	    };
+	    let chunk = lua.load(path);
+	    match chunk.exec() {
+		Ok(()) => { println!("lua returned ok"); },
+		Err(e) => {
+		    println!("lua error {:?}", e);
+		    exit(1);
+		},
+	    };
+	    exit(0);
 	},
-    };
-    exit(0);
+	Err(e) => {
+	    println!("fork error {:?}", e);
+	    None
+	}
+    }
 }
 
+fn read_ancillary_data(ancillary : SocketAncillary<'_>) -> Vec<i32> {
+    let mut fds : Vec<i32> = Vec::new();
+    for ancillary_result in ancillary.messages() {
+	if let AncillaryData::ScmRights(scm_rights) = ancillary_result.unwrap() {
+	    for fd in scm_rights {
+		println!("receive file descriptor: {fd}");
+		fds.push(fd);
+	    }
+	}
+    }
+    println!("fds {:?}", fds);
+    fds
+}
+
+fn split_command(buf : &[u8]) -> Vec<String> {
+    let mut words : Vec<String> = Vec::new();
+    for w in buf.split(|e| *e == 0) {
+	if let Ok(s) = str::from_utf8(w) {
+	    words.push(s.to_string());
+	}
+    }
+    words
+}
+
+
 fn main() -> std::io::Result<()> {
     let Ok(sock_path) = env::var("LUAD_SOCKET_PATH") else {
 	panic!("need to set LUAD_SOCKET_PATH env var");
@@ -43,6 +82,7 @@ fn main() -> std::io::Result<()> {
 
     let sock = UnixDatagram::bind(sock_path)?;
 
+    let mut peers : HashMap<i32, SocketAddr> = HashMap::new();
     // listen for datagrams. each time we get one, fork a child
     // to run lua script with the datagram payload and its stdio
     // connected to the passed fds. when the lua subprocess exits,
@@ -56,50 +96,35 @@ fn main() -> std::io::Result<()> {
 	];
 	let mut ancillary_buffer = [0; 128];
 	let mut ancillary = SocketAncillary::new(&mut ancillary_buffer[..]);
-	match sock.recv_vectored_with_ancillary(&mut bufs, &mut ancillary) {
-	    Ok((size, truncated)) => {
-		let mut fds : Vec<i32> = Vec::new();
-		for ancillary_result in ancillary.messages() {
-		    if let AncillaryData::ScmRights(scm_rights) = ancillary_result.unwrap() {
-			for fd in scm_rights {
-			    println!("receive file descriptor: {fd}");
-			    fds.push(fd);
-			}
-		    }
+	match sock.recv_vectored_with_ancillary_from(&mut bufs, &mut ancillary) {
+	    Ok((size, truncated, peer)) => {
+		let fds = read_ancillary_data(ancillary);
+		let args = split_command(&buf[..size-1]);
+		println!("args {:?} from {:?}", args, peer);
+		if let Some(child) = fork_lua(&lua, args, fds) {
+		    println!("forked {child}");
+		    peers.insert(child, peer);
 		}
-		println!("data {:?},  len {:?}", buf, size);
-		println!("fds {:?}", fds);
 
 	    },
 	    Err(e) => {
 		println!("error reading: {:?}", e);
 	    }
 	}
+
+
+	//     // println!("parent {:?} {:?}", pid, result);
+	//     match waitpid(pid) {
+	// 	Ok(status) => {
+	// 	    println!("exited {:?}", WEXITSTATUS(status));
+	// 	},
+	// 	Err(e) => {
+	// 	    println!("waitpid failed {:?}", e);
+	// 	}
+	//     }
+	// },
+
+
     }
 
-    // for pathname in io::stdin().lines() {
-    // 	let pathname = pathname.unwrap();
-    // 	let path = Path::new(&pathname);
-    // 	match fork() {
-    // 	    Ok(Fork::Parent(pid)) => {
-    // 		// println!("parent {:?} {:?}", pid, result);
-    // 		match waitpid(pid) {
-    // 		    Ok(status) => {
-    // 			println!("exited {:?}", WEXITSTATUS(status));
-    // 		    },
-    // 		    Err(e) => {
-    // 			println!("waitpid failed {:?}", e);
-    // 		    }
-    // 		}
-    // 	    },
-    // 	    Ok(Fork::Child) => {
-    // 		run_lua(&lua, &path);
-    // 	    }
-    // 	    Err(e) => {
-    // 		println!("fork error {:?}", e);
-    // 		exit(1);
-    // 	    }
-    // 	}
-    // };
-    // Ok(())
 }