Men 8382 mender artifact fails on calling mender update show provides

cli/util/ssh.go

@@ -0,0 +1,183 @@
+// Copyright 2025 Northern.tech AS
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+
+package util
+
+import (
+	"bufio"
+	"context"
+	"io"
+	"os"
+	"os/exec"
+	"os/signal"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/pkg/errors"
+	"github.com/urfave/cli"
+)
+
+type SSHCommand struct {
+	Cmd     *exec.Cmd
+	ctx     context.Context
+	Stdout  io.ReadCloser
+	cancel  context.CancelFunc
+	sigChan chan os.Signal
+	errChan chan error
+}
+
+func StartSSHCommand(c *cli.Context,
+	_ctx context.Context,
+	cancel context.CancelFunc,
+	command string,
+	sshConnectedToken string,
+) (*SSHCommand, error) {
+
+	var userAtHost string
+	var sigChan chan os.Signal
+	var errChan chan error
+	port := "22"
+	host := strings.TrimPrefix(c.String("file"), "ssh://")
+
+	if remotePort := strings.Split(host, ":"); len(remotePort) == 2 {
+		port = remotePort[1]
+		userAtHost = remotePort[0]
+	} else {
+		userAtHost = host
+	}
+
+	args := c.StringSlice("ssh-args")
+	// Check if port is specified explicitly with the --ssh-args flag
+	addPort := true
+	for _, arg := range args {
+		if strings.Contains(arg, "-p") {
+			addPort = false
+			break
+		}
+	}
+	if addPort {
+		args = append(args, "-p", port)
+	}
+	args = append(args, userAtHost)
+	args = append(
+		args,
+		"/bin/sh",
+		"-c",
+		command)
+
+	cmd := exec.Command("ssh", args...)
+
+	// Simply connect stdin/stderr
+	cmd.Stdin = os.Stdin
+	cmd.Stderr = os.Stderr
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return nil, errors.New("Error redirecting stdout on exec")
+	}
+
+	// Disable tty echo before starting
+	term, err := DisableEcho(int(os.Stdin.Fd()))
+	if err == nil {
+		sigChan = make(chan os.Signal, 1)
+		errChan = make(chan error, 1)
+		// Make sure that echo is enabled if the process gets
+		// interrupted
+		signal.Notify(sigChan)
+		go EchoSigHandler(_ctx, sigChan, errChan, term)
+	} else if err != syscall.ENOTTY {
+		return nil, err
+	}
+
+	if err := cmd.Start(); err != nil {
+		return nil, err
+	}
+
+	// Wait for 120 seconds for ssh to establish connection
+	err = waitForBufferSignal(stdout, os.Stdout, sshConnectedToken, 2*time.Minute)
+	if err != nil {
+		_ = cmd.Process.Kill()
+		return nil, errors.Wrap(err,
+			"Error waiting for ssh session to be established.")
+	}
+	return &SSHCommand{
+		ctx:     _ctx,
+		Cmd:     cmd,
+		Stdout:  stdout,
+		cancel:  cancel,
+		sigChan: sigChan,
+		errChan: errChan,
+	}, nil
+}
+
+func (s *SSHCommand) EndSSHCommand() error {
+	if s.Cmd.ProcessState != nil && s.Cmd.ProcessState.Exited() {
+		return errors.New("SSH session closed unexpectedly")
+	}
+
+	if err := s.Cmd.Wait(); err != nil {
+		return errors.Wrap(err,
+			"SSH session closed with error")
+	}
+
+	if s.sigChan != nil {
+		signal.Stop(s.sigChan)
+		s.cancel()
+		if err := <-s.errChan; err != nil {
+			return err
+		}
+	} else {
+		s.cancel()
+	}
+
+	return nil
+}
+
+// Reads from src waiting for the string specified by signal, writing all other
+// output appearing at src to sink. The function returns an error if occurs
+// reading from the stream or the deadline exceeds.
+func waitForBufferSignal(src io.Reader, sink io.Writer,
+	signal string, deadline time.Duration) error {
+
+	var err error
+	errChan := make(chan error)
+
+	go func() {
+		stdoutRdr := bufio.NewReader(src)
+		for {
+			line, err := stdoutRdr.ReadString('\n')
+			if err != nil {
+				errChan <- err
+				break
+			}
+			if strings.Contains(line, signal) {
+				errChan <- nil
+				break
+			}
+			_, err = sink.Write([]byte(line + "\n"))
+			if err != nil {
+				errChan <- err
+				break
+			}
+		}
+	}()
+
+	select {
+	case err = <-errChan:
+		// Error from goroutine
+	case <-time.After(deadline):
+		err = errors.New("Input deadline exceeded")
+	}
+	return err
+}