v2podman attach and exec

add the ability to attach to a running container.  the tunnel side of this is not enabled yet as we have work on the endpoints and plumbing to do yet.

add the ability to exec a command in a running container.  the tunnel side is also being deferred for same reason.

Signed-off-by: Brent Baude <bbaude@redhat.com>

3 files changed, 273 insertions, 0 deletions

diff --git a/pkg/domain/infra/abi/terminal/sigproxy_linux.go b/pkg/domain/infra/abi/terminal/sigproxy_linux.go
new file mode 100644
index 000000000..d7f5853d8
--- /dev/null
+++ b/pkg/domain/infra/abi/terminal/sigproxy_linux.go
@@ -0,0 +1,47 @@
+// +build ABISupport
+
+package terminal
+
+import (
+	"os"
+	"syscall"
+
+	"github.com/containers/libpod/libpod"
+	"github.com/containers/libpod/pkg/signal"
+	"github.com/sirupsen/logrus"
+)
+
+// ProxySignals ...
+func ProxySignals(ctr *libpod.Container) {
+	sigBuffer := make(chan os.Signal, 128)
+	signal.CatchAll(sigBuffer)
+
+	logrus.Debugf("Enabling signal proxying")
+
+	go func() {
+		for s := range sigBuffer {
+			// Ignore SIGCHLD and SIGPIPE - these are mostly likely
+			// intended for the podman command itself.
+			// SIGURG was added because of golang 1.14 and its preemptive changes
+			// causing more signals to "show up".
+			// https://github.com/containers/libpod/issues/5483
+			if s == syscall.SIGCHLD || s == syscall.SIGPIPE || s == syscall.SIGURG {
+				continue
+			}
+
+			if err := ctr.Kill(uint(s.(syscall.Signal))); err != nil {
+				// If the container dies, and we find out here,
+				// we need to forward that one signal to
+				// ourselves so that it is not lost, and then
+				// we terminate the proxy and let the defaults
+				// play out.
+				logrus.Errorf("Error forwarding signal %d to container %s: %v", s, ctr.ID(), err)
+				signal.StopCatch(sigBuffer)
+				if err := syscall.Kill(syscall.Getpid(), s.(syscall.Signal)); err != nil {
+					logrus.Errorf("failed to kill pid %d", syscall.Getpid())
+				}
+				return
+			}
+		}
+	}()
+}
diff --git a/pkg/domain/infra/abi/terminal/terminal.go b/pkg/domain/infra/abi/terminal/terminal.go
new file mode 100644
index 000000000..f187bdd6b
--- /dev/null
+++ b/pkg/domain/infra/abi/terminal/terminal.go
@@ -0,0 +1,103 @@
+// +build ABISupport
+
+package terminal
+
+import (
+	"context"
+	"os"
+	"os/signal"
+
+	lsignal "github.com/containers/libpod/pkg/signal"
+	"github.com/docker/docker/pkg/term"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"k8s.io/client-go/tools/remotecommand"
+)
+
+// RawTtyFormatter ...
+type RawTtyFormatter struct {
+}
+
+// getResize returns a TerminalSize command matching stdin's current
+// size on success, and nil on errors.
+func getResize() *remotecommand.TerminalSize {
+	winsize, err := term.GetWinsize(os.Stdin.Fd())
+	if err != nil {
+		logrus.Warnf("Could not get terminal size %v", err)
+		return nil
+	}
+	return &remotecommand.TerminalSize{
+		Width:  winsize.Width,
+		Height: winsize.Height,
+	}
+}
+
+// Helper for prepareAttach - set up a goroutine to generate terminal resize events
+func resizeTty(ctx context.Context, resize chan remotecommand.TerminalSize) {
+	sigchan := make(chan os.Signal, 1)
+	signal.Notify(sigchan, lsignal.SIGWINCH)
+	go func() {
+		defer close(resize)
+		// Update the terminal size immediately without waiting
+		// for a SIGWINCH to get the correct initial size.
+		resizeEvent := getResize()
+		for {
+			if resizeEvent == nil {
+				select {
+				case <-ctx.Done():
+					return
+				case <-sigchan:
+					resizeEvent = getResize()
+				}
+			} else {
+				select {
+				case <-ctx.Done():
+					return
+				case <-sigchan:
+					resizeEvent = getResize()
+				case resize <- *resizeEvent:
+					resizeEvent = nil
+				}
+			}
+		}
+	}()
+}
+
+func restoreTerminal(state *term.State) error {
+	logrus.SetFormatter(&logrus.TextFormatter{})
+	return term.RestoreTerminal(os.Stdin.Fd(), state)
+}
+
+// Format ...
+func (f *RawTtyFormatter) Format(entry *logrus.Entry) ([]byte, error) {
+	textFormatter := logrus.TextFormatter{}
+	bytes, err := textFormatter.Format(entry)
+
+	if err == nil {
+		bytes = append(bytes, '\r')
+	}
+
+	return bytes, err
+}
+
+func handleTerminalAttach(ctx context.Context, resize chan remotecommand.TerminalSize) (context.CancelFunc, *term.State, error) {
+	logrus.Debugf("Handling terminal attach")
+
+	subCtx, cancel := context.WithCancel(ctx)
+
+	resizeTty(subCtx, resize)
+
+	oldTermState, err := term.SaveState(os.Stdin.Fd())
+	if err != nil {
+		// allow caller to not have to do any cleaning up if we error here
+		cancel()
+		return nil, nil, errors.Wrapf(err, "unable to save terminal state")
+	}
+
+	logrus.SetFormatter(&RawTtyFormatter{})
+	if _, err := term.SetRawTerminal(os.Stdin.Fd()); err != nil {
+		return cancel, nil, err
+	}
+
+	return cancel, oldTermState, nil
+}
diff --git a/pkg/domain/infra/abi/terminal/terminal_linux.go b/pkg/domain/infra/abi/terminal/terminal_linux.go
new file mode 100644
index 000000000..664205df1
--- /dev/null
+++ b/pkg/domain/infra/abi/terminal/terminal_linux.go
@@ -0,0 +1,123 @@
+// +build ABISupport
+
+package terminal
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"os"
+
+	"github.com/containers/libpod/libpod"
+	"github.com/containers/libpod/libpod/define"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/crypto/ssh/terminal"
+	"k8s.io/client-go/tools/remotecommand"
+)
+
+// ExecAttachCtr execs and attaches to a container
+func ExecAttachCtr(ctx context.Context, ctr *libpod.Container, tty, privileged bool, env map[string]string, cmd []string, user, workDir string, streams *define.AttachStreams, preserveFDs uint, detachKeys string) (int, error) {
+	resize := make(chan remotecommand.TerminalSize)
+	haveTerminal := terminal.IsTerminal(int(os.Stdin.Fd()))
+
+	// Check if we are attached to a terminal. If we are, generate resize
+	// events, and set the terminal to raw mode
+	if haveTerminal && tty {
+		cancel, oldTermState, err := handleTerminalAttach(ctx, resize)
+		if err != nil {
+			return -1, err
+		}
+		defer cancel()
+		defer func() {
+			if err := restoreTerminal(oldTermState); err != nil {
+				logrus.Errorf("unable to restore terminal: %q", err)
+			}
+		}()
+	}
+
+	execConfig := new(libpod.ExecConfig)
+	execConfig.Command = cmd
+	execConfig.Terminal = tty
+	execConfig.Privileged = privileged
+	execConfig.Environment = env
+	execConfig.User = user
+	execConfig.WorkDir = workDir
+	execConfig.DetachKeys = &detachKeys
+	execConfig.PreserveFDs = preserveFDs
+
+	return ctr.Exec(execConfig, streams, resize)
+}
+
+// StartAttachCtr starts and (if required) attaches to a container
+// if you change the signature of this function from os.File to io.Writer, it will trigger a downstream
+// error. we may need to just lint disable this one.
+func StartAttachCtr(ctx context.Context, ctr *libpod.Container, stdout, stderr, stdin *os.File, detachKeys string, sigProxy bool, startContainer bool, recursive bool) error { //nolint-interfacer
+	resize := make(chan remotecommand.TerminalSize)
+
+	haveTerminal := terminal.IsTerminal(int(os.Stdin.Fd()))
+
+	// Check if we are attached to a terminal. If we are, generate resize
+	// events, and set the terminal to raw mode
+	if haveTerminal && ctr.Spec().Process.Terminal {
+		cancel, oldTermState, err := handleTerminalAttach(ctx, resize)
+		if err != nil {
+			return err
+		}
+		defer func() {
+			if err := restoreTerminal(oldTermState); err != nil {
+				logrus.Errorf("unable to restore terminal: %q", err)
+			}
+		}()
+		defer cancel()
+	}
+
+	streams := new(define.AttachStreams)
+	streams.OutputStream = stdout
+	streams.ErrorStream = stderr
+	streams.InputStream = bufio.NewReader(stdin)
+	streams.AttachOutput = true
+	streams.AttachError = true
+	streams.AttachInput = true
+
+	if stdout == nil {
+		logrus.Debugf("Not attaching to stdout")
+		streams.AttachOutput = false
+	}
+	if stderr == nil {
+		logrus.Debugf("Not attaching to stderr")
+		streams.AttachError = false
+	}
+	if stdin == nil {
+		logrus.Debugf("Not attaching to stdin")
+		streams.AttachInput = false
+	}
+
+	if !startContainer {
+		if sigProxy {
+			ProxySignals(ctr)
+		}
+
+		return ctr.Attach(streams, detachKeys, resize)
+	}
+
+	attachChan, err := ctr.StartAndAttach(ctx, streams, detachKeys, resize, recursive)
+	if err != nil {
+		return err
+	}
+
+	if sigProxy {
+		ProxySignals(ctr)
+	}
+
+	if stdout == nil && stderr == nil {
+		fmt.Printf("%s\n", ctr.ID())
+	}
+
+	err = <-attachChan
+	if err != nil {
+		return errors.Wrapf(err, "error attaching to container %s", ctr.ID())
+	}
+
+	return nil
+}