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Diffstat (limited to 'src/tools/qemu-test-server/src/main.rs')
| -rw-r--r-- | src/tools/qemu-test-server/src/main.rs | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/src/tools/qemu-test-server/src/main.rs b/src/tools/qemu-test-server/src/main.rs new file mode 100644 index 00000000000..1c5d7b915ba --- /dev/null +++ b/src/tools/qemu-test-server/src/main.rs @@ -0,0 +1,232 @@ +// Copyright 2017 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +/// This is a small server which is intended to run inside of an emulator. This +/// server pairs with the `qemu-test-client` program in this repository. The +/// `qemu-test-client` connects to this server over a TCP socket and performs +/// work such as: +/// +/// 1. Pushing shared libraries to the server +/// 2. Running tests through the server +/// +/// The server supports running tests concurrently and also supports tests +/// themselves having support libraries. All data over the TCP sockets is in a +/// basically custom format suiting our needs. + +use std::fs::{self, File, Permissions}; +use std::io::prelude::*; +use std::io::{self, BufReader}; +use std::net::{TcpListener, TcpStream}; +use std::os::unix::prelude::*; +use std::sync::{Arc, Mutex}; +use std::path::Path; +use std::str; +use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering}; +use std::thread; +use std::process::{Command, Stdio}; + +macro_rules! t { + ($e:expr) => (match $e { + Ok(e) => e, + Err(e) => panic!("{} failed with {}", stringify!($e), e), + }) +} + +static TEST: AtomicUsize = ATOMIC_USIZE_INIT; + +fn main() { + println!("starting test server"); + let listener = t!(TcpListener::bind("10.0.2.15:12345")); + println!("listening!"); + + let work = Path::new("/tmp/work"); + t!(fs::create_dir_all(work)); + + let lock = Arc::new(Mutex::new(())); + + for socket in listener.incoming() { + let mut socket = t!(socket); + let mut buf = [0; 4]; + t!(socket.read_exact(&mut buf)); + if &buf[..] == b"ping" { + t!(socket.write_all(b"pong")); + } else if &buf[..] == b"push" { + handle_push(socket, work); + } else if &buf[..] == b"run " { + let lock = lock.clone(); + thread::spawn(move || handle_run(socket, work, &lock)); + } else { + panic!("unknown command {:?}", buf); + } + } +} + +fn handle_push(socket: TcpStream, work: &Path) { + let mut reader = BufReader::new(socket); + let mut filename = Vec::new(); + t!(reader.read_until(0, &mut filename)); + filename.pop(); // chop off the 0 + let filename = t!(str::from_utf8(&filename)); + + let path = work.join(filename); + t!(io::copy(&mut reader, &mut t!(File::create(&path)))); + t!(fs::set_permissions(&path, Permissions::from_mode(0o755))); +} + +struct RemoveOnDrop<'a> { + inner: &'a Path, +} + +impl<'a> Drop for RemoveOnDrop<'a> { + fn drop(&mut self) { + t!(fs::remove_dir_all(self.inner)); + } +} + +fn handle_run(socket: TcpStream, work: &Path, lock: &Mutex<()>) { + let mut arg = Vec::new(); + let mut reader = BufReader::new(socket); + + // Allocate ourselves a directory that we'll delete when we're done to save + // space. + let n = TEST.fetch_add(1, Ordering::SeqCst); + let path = work.join(format!("test{}", n)); + let exe = path.join("exe"); + t!(fs::create_dir(&path)); + let _a = RemoveOnDrop { inner: &path }; + + // First up we'll get a list of arguments delimited with 0 bytes. An empty + // argument means that we're done. + let mut cmd = Command::new(&exe); + while t!(reader.read_until(0, &mut arg)) > 1 { + cmd.arg(t!(str::from_utf8(&arg[..arg.len() - 1]))); + arg.truncate(0); + } + + // Next we'll get a bunch of env vars in pairs delimited by 0s as well + arg.truncate(0); + while t!(reader.read_until(0, &mut arg)) > 1 { + let key_len = arg.len() - 1; + let val_len = t!(reader.read_until(0, &mut arg)) - 1; + { + let key = &arg[..key_len]; + let val = &arg[key_len + 1..][..val_len]; + let key = t!(str::from_utf8(key)); + let val = t!(str::from_utf8(val)); + cmd.env(key, val); + } + arg.truncate(0); + } + + // The section of code from here down to where we drop the lock is going to + // be a critical section for us. On Linux you can't execute a file which is + // open somewhere for writing, as you'll receive the error "text file busy". + // Now here we never have the text file open for writing when we spawn it, + // so why do we still need a critical section? + // + // Process spawning first involves a `fork` on Unix, which clones all file + // descriptors into the child process. This means that it's possible for us + // to open the file for writing (as we're downloading it), then some other + // thread forks, then we close the file and try to exec. At that point the + // other thread created a child process with the file open for writing, and + // we attempt to execute it, so we get an error. + // + // This race is resolve by ensuring that only one thread can writ ethe file + // and spawn a child process at once. Kinda an unfortunate solution, but we + // don't have many other choices with this sort of setup! + // + // In any case the lock is acquired here, before we start writing any files. + // It's then dropped just after we spawn the child. That way we don't lock + // the execution of the child, just the creation of its files. + let lock = lock.lock(); + + // Next there's a list of dynamic libraries preceded by their filenames. + arg.truncate(0); + while t!(reader.read_until(0, &mut arg)) > 1 { + let dst = path.join(t!(str::from_utf8(&arg[..arg.len() - 1]))); + let amt = read_u32(&mut reader) as u64; + t!(io::copy(&mut reader.by_ref().take(amt), + &mut t!(File::create(&dst)))); + t!(fs::set_permissions(&dst, Permissions::from_mode(0o755))); + arg.truncate(0); + } + + // Finally we'll get the binary. The other end will tell us how big the + // binary is and then we'll download it all to the exe path we calculated + // earlier. + let amt = read_u32(&mut reader) as u64; + t!(io::copy(&mut reader.by_ref().take(amt), + &mut t!(File::create(&exe)))); + t!(fs::set_permissions(&exe, Permissions::from_mode(0o755))); + + // Support libraries were uploaded to `work` earlier, so make sure that's + // in `LD_LIBRARY_PATH`. Also include our own current dir which may have + // had some libs uploaded. + cmd.env("LD_LIBRARY_PATH", + format!("{}:{}", work.display(), path.display())); + + // Spawn the child and ferry over stdout/stderr to the socket in a framed + // fashion (poor man's style) + let mut child = t!(cmd.stdin(Stdio::null()) + .stdout(Stdio::piped()) + .stderr(Stdio::piped()) + .spawn()); + drop(lock); + let mut stdout = child.stdout.take().unwrap(); + let mut stderr = child.stderr.take().unwrap(); + let socket = Arc::new(Mutex::new(reader.into_inner())); + let socket2 = socket.clone(); + let thread = thread::spawn(move || my_copy(&mut stdout, 0, &*socket2)); + my_copy(&mut stderr, 1, &*socket); + thread.join().unwrap(); + + // Finally send over the exit status. + let status = t!(child.wait()); + let (which, code) = match status.code() { + Some(n) => (0, n), + None => (1, status.signal().unwrap()), + }; + t!(socket.lock().unwrap().write_all(&[ + which, + (code >> 24) as u8, + (code >> 16) as u8, + (code >> 8) as u8, + (code >> 0) as u8, + ])); +} + +fn my_copy(src: &mut Read, which: u8, dst: &Mutex<Write>) { + let mut b = [0; 1024]; + loop { + let n = t!(src.read(&mut b)); + let mut dst = dst.lock().unwrap(); + t!(dst.write_all(&[ + which, + (n >> 24) as u8, + (n >> 16) as u8, + (n >> 8) as u8, + (n >> 0) as u8, + ])); + if n > 0 { + t!(dst.write_all(&b[..n])); + } else { + break + } + } +} + +fn read_u32(r: &mut Read) -> u32 { + let mut len = [0; 4]; + t!(r.read_exact(&mut len)); + ((len[0] as u32) << 24) | + ((len[1] as u32) << 16) | + ((len[2] as u32) << 8) | + ((len[3] as u32) << 0) +} |