Example #1
0
func (s *Splicer) splice(direction string, inFD, outFD int, wg *sync.WaitGroup) {
	// Signal to the caller that we're done
	defer func() {
		// If a reliable delivery socket has data associated with it when a close takes place, the system continues to attempt data transfer.
		if err := syscall.Shutdown(inFD, SHUT_RDWR); err != nil {
			log.Printf("Shutdown err %v", err)
		}
		if err := syscall.Shutdown(outFD, SHUT_RDWR); err != nil {
			log.Printf("Shutdown err %v", err)
		}
		if wg != nil {
			wg.Done()
		}
	}()

	pipe := make([]int, 2)
	if err := syscall.Pipe(pipe); err != nil {
		log.Fatal(err)
	}
	defer func() {
		syscall.Close(pipe[0])
		syscall.Close(pipe[1])
	}()

	var netWrittenBytes, netReadBytes int64
	log.Printf("[%v] Splicing pipe %+v, tcpfds %+v", direction, s.pipe, s.tcpFD)
	for {
		// SPLICE_F_NONBLOCK: don't block if TCP buffer is empty
		// SPLICE_F_MOVE: directly move pages into splice buffer in kernel memory
		// SPLICE_F_MORE: just makes mysql connections slow
		log.Printf("[input (%v)] Entering input", direction)
		inBytes, err := syscall.Splice(inFD, nil, pipe[1], nil, s.bufferSize, SPLICE_F_NONBLOCK)
		if err := s.checkSpliceErr(inBytes, err, fmt.Sprintf("input (%v)", direction)); err != nil {
			log.Printf("ERROR [input (%v)] error: %v", direction, err)
			return
		}
		netReadBytes += inBytes
		log.Printf("[input (%v)] %d bytes read", direction, inBytes)

		log.Printf("[input (%v)] Entering output", direction)
		outBytes, err := syscall.Splice(pipe[0], nil, outFD, nil, s.bufferSize, SPLICE_F_NONBLOCK)
		if err := s.checkSpliceErr(inBytes, err, fmt.Sprintf("output (%v)", direction)); err != nil {
			log.Printf("ERROR [output (%v)] error: %v", direction, err)
			return
		}
		log.Printf("[output (%v)] %d bytes written, out of given input %d", direction, outBytes, inBytes)
		netWrittenBytes += outBytes
	}
	log.Printf("[%v] Spliced %d bytes read %d bytes written", direction, netWrittenBytes, netReadBytes)
}
Example #2
0
// createFDProxies creates pipes at /dev/stdout and /dev/stderr and copies data
// written to them to the job's stdout and stderr streams respectively.
//
// This is necessary (rather than just symlinking those paths to /proc/self/fd/{1,2})
// because the standard streams are sockets, and calling open(2) on a socket
// leads to an ENXIO error (see http://marc.info/?l=ast-users&m=120978595414993).
func createFDProxies(cmd *exec.Cmd) error {
	for path, dst := range map[string]*os.File{
		"/dev/stdout": cmd.Stdout.(*os.File),
		"/dev/stderr": cmd.Stderr.(*os.File),
	} {
		os.Remove(path)
		if err := syscall.Mkfifo(path, 0666); err != nil {
			return err
		}
		pipe, err := os.OpenFile(path, os.O_RDWR, os.ModeNamedPipe)
		if err != nil {
			return err
		}
		go func(dst *os.File) {
			defer pipe.Close()
			for {
				// copy data from the pipe to dst using splice(2) (rather than io.Copy)
				// to avoid a needless copy through user space
				n, err := syscall.Splice(int(pipe.Fd()), nil, int(dst.Fd()), nil, 65535, 0)
				if err != nil || n == 0 {
					return
				}
			}
		}(dst)
	}
	return nil
}
Example #3
0
func (p *Pair) WriteTo(fd uintptr, n int) (int, error) {
	m, err := syscall.Splice(int(p.r.Fd()), nil, int(fd), nil, int(n), 0)
	if err != nil {
		err = os.NewSyscallError("Splice write", err)
	}
	return int(m), err
}
Example #4
0
func main() {
	log.Printf("Input file %v", *inFile)
	in, err := os.Open(*inFile)
	if err != nil {
		log.Fatal(err)
	}
	defer in.Close()
	inFD := int(in.Fd())

	log.Printf("Output file %v", *outFile)
	out, err := os.Create(*outFile)
	if err != nil {
		log.Fatal(err)
	}
	defer out.Close()
	outFD := int(out.Fd())

	pipe := make([]int, 2)
	if err := syscall.Pipe(pipe); err != nil {
		log.Fatal(err)
	}
	defer syscall.Close(pipe[0])
	defer syscall.Close(pipe[1])

	flags := SPLICE_F_NONBLOCK
	blockSize := 1
	inFileSize := fileSize(in)
	var netRead int64

	for {
		inBytes, err := syscall.Splice(inFD, nil, pipe[1], nil, blockSize, flags)
		checkSpliceErr(inBytes, err, "input")
		netRead += inBytes
		log.Printf("[input] %d bytes read, %d remaining", inBytes, inFileSize-netRead)

		if err := syscall.SetNonblock(inFD, true); err != nil {
			log.Fatalf("Unable to close in fd")
		}

		outBytes, err := syscall.Splice(pipe[0], nil, outFD, nil, blockSize, flags)
		checkSpliceErr(outBytes, err, "output")
		log.Printf("[output] %d bytes written, out of given input %d", outBytes, inBytes)
	}
}
Example #5
0
func (p *Pair) LoadFrom(fd uintptr, sz int) (int, error) {
	if sz > p.size {
		return 0, fmt.Errorf("LoadFrom: not enough space %d, %d",
			sz, p.size)
	}

	n, err := syscall.Splice(int(fd), nil, int(p.w.Fd()), nil, sz, 0)
	if err != nil {
		err = os.NewSyscallError("Splice load from", err)
	}
	return int(n), err
}
Example #6
0
// splices all contents out to the specified file, updates outOff
func (p *pipe) spliceOut(out *os.File, outOff *int64) error {
	toSplice := p.numInBuffer
	for toSplice > 0 {
		n, err := syscall.Splice(int(p.r.Fd()), nil, int(out.Fd()), outOff, toSplice, 0)
		if err != nil {
			return err
		}
		toSplice -= int(n)
		if outOff != nil {
			*outOff -= n
		}
	}
	p.numInBuffer = 0
	return nil
}
Example #7
0
func (p *pipe) spliceIn(in *os.File, inOff *int64, length int) (int64, error) {
	if p.numInBuffer+length > PIPELEN {
		length = PIPELEN - p.numInBuffer
	}
	spliced := int64(0)
	for spliced < int64(length) {
		w, err := syscall.Splice(int(in.Fd()), inOff, int(p.w.Fd()), nil, length, 0)
		if err != nil {
			return spliced, err
		}
		spliced += w
		if inOff != nil {
			*inOff += w
		}
	}
	return spliced, nil
}
Example #8
0
func (p *Pair) LoadFromAt(fd uintptr, sz int, off int64) (int, error) {
	n, err := syscall.Splice(int(fd), &off, int(p.w.Fd()), nil, sz, 0)
	return int(n), err
}
Example #9
0
// Run as pid 1 and monitor the contained process to return its exit code.
func containerInitApp(c *Config, logFile *os.File) error {
	log := logger.New()

	init := newContainerInit(c, logFile)
	log.Debug("registering RPC server")
	if err := rpcplus.Register(init); err != nil {
		log.Error("error registering RPC server", "err", err)
		return err
	}
	init.mtx.Lock()
	defer init.mtx.Unlock()

	// Prepare the cmd based on the given args
	// If this fails we report that below
	cmdPath, cmdErr := getCmdPath(c)
	cmd := exec.Command(cmdPath, c.Args[1:]...)
	cmd.Dir = c.WorkDir

	cmd.Env = make([]string, 0, len(c.Env))
	for k, v := range c.Env {
		cmd.Env = append(cmd.Env, k+"="+v)
	}

	// App runs in its own session
	cmd.SysProcAttr = &syscall.SysProcAttr{Setsid: true}

	if c.Uid != nil || c.Gid != nil {
		cmd.SysProcAttr.Credential = &syscall.Credential{}
		if c.Uid != nil {
			cmd.SysProcAttr.Credential.Uid = *c.Uid
		}
		if c.Gid != nil {
			cmd.SysProcAttr.Credential.Gid = *c.Gid
		}
	}

	// Console setup.  Hook up the container app's stdin/stdout/stderr to
	// either a pty or pipes.  The FDs for the controlling side of the
	// pty/pipes will be passed to flynn-host later via a UNIX socket.
	if c.TTY {
		log.Debug("creating PTY")
		ptyMaster, ptySlave, err := pty.Open()
		if err != nil {
			log.Error("error creating PTY", "err", err)
			return err
		}
		init.ptyMaster = ptyMaster
		cmd.Stdout = ptySlave
		cmd.Stderr = ptySlave
		if c.OpenStdin {
			log.Debug("attaching stdin to PTY")
			cmd.Stdin = ptySlave
			cmd.SysProcAttr.Setctty = true
		}
		if c.Uid != nil && c.Gid != nil {
			if err := syscall.Fchown(int(ptySlave.Fd()), int(*c.Uid), int(*c.Gid)); err != nil {
				log.Error("error changing PTY ownership", "err", err)
				return err
			}
		}
	} else {
		// We copy through a socketpair (rather than using cmd.StdoutPipe directly) to make
		// it easier for flynn-host to do non-blocking I/O (via net.FileConn) so that no
		// read(2) calls can succeed after closing the logs during an update.
		//
		// We also don't assign the socketpair directly to fd 1 because that prevents jobs
		// using /dev/stdout (calling open(2) on a socket leads to an ENXIO error, see
		// http://marc.info/?l=ast-users&m=120978595414993).
		newPipe := func(pipeFn func() (io.ReadCloser, error), name string) (*os.File, error) {
			pipe, err := pipeFn()
			if err != nil {
				return nil, err
			}
			if c.Uid != nil && c.Gid != nil {
				if err := syscall.Fchown(int(pipe.(*os.File).Fd()), int(*c.Uid), int(*c.Gid)); err != nil {
					return nil, err
				}
			}
			sockR, sockW, err := newSocketPair(name)
			if err != nil {
				return nil, err
			}
			go func() {
				defer sockW.Close()
				for {
					// copy data from the pipe to the socket using splice(2)
					// (rather than io.Copy) to avoid a needless copy through
					// user space
					n, err := syscall.Splice(int(pipe.(*os.File).Fd()), nil, int(sockW.Fd()), nil, 65535, 0)
					if err != nil || n == 0 {
						return
					}
				}
			}()
			return sockR, nil
		}

		log.Debug("creating stdout pipe")
		var err error
		init.stdout, err = newPipe(cmd.StdoutPipe, "stdout")
		if err != nil {
			log.Error("error creating stdout pipe", "err", err)
			return err
		}

		log.Debug("creating stderr pipe")
		init.stderr, err = newPipe(cmd.StderrPipe, "stderr")
		if err != nil {
			log.Error("error creating stderr pipe", "err", err)
			return err
		}

		if c.OpenStdin {
			// Can't use cmd.StdinPipe() here, since in Go 1.2 it
			// returns an io.WriteCloser with the underlying object
			// being an *exec.closeOnce, neither of which provides
			// a way to convert to an FD.
			log.Debug("creating stdin pipe")
			pipeRead, pipeWrite, err := os.Pipe()
			if err != nil {
				log.Error("creating stdin pipe", "err", err)
				return err
			}
			cmd.Stdin = pipeRead
			init.stdin = pipeWrite
		}
	}

	go runRPCServer()

	// Wait for flynn-host to tell us to start
	init.mtx.Unlock() // Allow calls
	log.Debug("waiting to be resumed")
	<-init.resume
	log.Debug("resuming")
	init.mtx.Lock()

	log.Info("starting the job", "args", cmd.Args)
	if cmdErr != nil {
		log.Error("error starting the job", "err", cmdErr)
		init.changeState(StateFailed, cmdErr.Error(), -1)
		init.exit(1)
	}
	if err := cmd.Start(); err != nil {
		log.Error("error starting the job", "err", err)
		init.changeState(StateFailed, err.Error(), -1)
		init.exit(1)
	}
	log.Debug("setting state to running")
	init.process = cmd.Process
	init.changeState(StateRunning, "", -1)

	init.mtx.Unlock() // Allow calls
	// monitor services
	hbs := make([]discoverd.Heartbeater, 0, len(c.Ports))
	for _, port := range c.Ports {
		if port.Service == nil {
			continue
		}
		log := log.New("name", port.Service.Name, "port", port.Port, "proto", port.Proto)
		log.Info("monitoring service")
		hb, err := monitor(port, init, c.Env, log)
		if err != nil {
			log.Error("error monitoring service", "err", err)
			os.Exit(70)
		}
		hbs = append(hbs, hb)
	}
	exitCode := babySit(init, hbs)
	log.Info("job exited", "status", exitCode)
	init.mtx.Lock()
	init.changeState(StateExited, "", exitCode)
	init.mtx.Unlock() // Allow calls

	log.Info("exiting")
	init.exit(exitCode)
	return nil
}