Fix resize race with podman exec -it

When starting a process with `podman exec -it` the terminal is resized
after the process is started. To fix this allow exec start to accept the
terminal height and width as parameter and let it resize right before
the process is started.

Fixes #10560

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

5 files changed, 44 insertions, 16 deletions

diff --git a/libpod/container_exec.go b/libpod/container_exec.go
index 737bf74ad..5d4bcb422 100644
--- a/libpod/container_exec.go
+++ b/libpod/container_exec.go
@@ -277,9 +277,10 @@ func (c *Container) ExecStart(sessionID string) error {
 }
 
 // ExecStartAndAttach starts and attaches to an exec session in a container.
+// newSize resizes the tty to this size before the process is started, must be nil if the exec session has no tty
 // TODO: Should we include detach keys in the signature to allow override?
 // TODO: How do we handle AttachStdin/AttachStdout/AttachStderr?
-func (c *Container) ExecStartAndAttach(sessionID string, streams *define.AttachStreams) error {
+func (c *Container) ExecStartAndAttach(sessionID string, streams *define.AttachStreams, newSize *define.TerminalSize) error {
 	if !c.batched {
 		c.lock.Lock()
 		defer c.lock.Unlock()
@@ -310,7 +311,7 @@ func (c *Container) ExecStartAndAttach(sessionID string, streams *define.AttachS
 		return err
 	}
 
-	pid, attachChan, err := c.ociRuntime.ExecContainer(c, session.ID(), opts, streams)
+	pid, attachChan, err := c.ociRuntime.ExecContainer(c, session.ID(), opts, streams, newSize)
 	if err != nil {
 		return err
 	}
@@ -373,7 +374,9 @@ func (c *Container) ExecStartAndAttach(sessionID string, streams *define.AttachS
 }
 
 // ExecHTTPStartAndAttach starts and performs an HTTP attach to an exec session.
-func (c *Container) ExecHTTPStartAndAttach(sessionID string, r *http.Request, w http.ResponseWriter, streams *HTTPAttachStreams, detachKeys *string, cancel <-chan bool, hijackDone chan<- bool) error {
+// newSize resizes the tty to this size before the process is started, must be nil if the exec session has no tty
+func (c *Container) ExecHTTPStartAndAttach(sessionID string, r *http.Request, w http.ResponseWriter,
+	streams *HTTPAttachStreams, detachKeys *string, cancel <-chan bool, hijackDone chan<- bool, newSize *define.TerminalSize) error {
 	// TODO: How do we combine streams with the default streams set in the exec session?
 
 	// Ensure that we don't leak a goroutine here
@@ -431,7 +434,7 @@ func (c *Container) ExecHTTPStartAndAttach(sessionID string, r *http.Request, w
 		close(holdConnOpen)
 	}()
 
-	pid, attachChan, err := c.ociRuntime.ExecContainerHTTP(c, session.ID(), execOpts, r, w, streams, cancel, hijackDone, holdConnOpen)
+	pid, attachChan, err := c.ociRuntime.ExecContainerHTTP(c, session.ID(), execOpts, r, w, streams, cancel, hijackDone, holdConnOpen, newSize)
 	if err != nil {
 		session.State = define.ExecStateStopped
 		session.ExitCode = define.TranslateExecErrorToExitCode(define.ExecErrorCodeGeneric, err)
@@ -719,7 +722,10 @@ func (c *Container) Exec(config *ExecConfig, streams *define.AttachStreams, resi
 	// API there.
 	// TODO: Refactor so this is closed here, before we remove the exec
 	// session.
+	var size *define.TerminalSize
 	if resize != nil {
+		s := <-resize
+		size = &s
 		go func() {
 			logrus.Debugf("Sending resize events to exec session %s", sessionID)
 			for resizeRequest := range resize {
@@ -737,7 +743,7 @@ func (c *Container) Exec(config *ExecConfig, streams *define.AttachStreams, resi
 		}()
 	}
 
-	if err := c.ExecStartAndAttach(sessionID, streams); err != nil {
+	if err := c.ExecStartAndAttach(sessionID, streams, size); err != nil {
 		return -1, err
 	}
 
diff --git a/libpod/oci.go b/libpod/oci.go
index 1f2c7dd71..c92d9a077 100644
--- a/libpod/oci.go
+++ b/libpod/oci.go
@@ -72,13 +72,16 @@ type OCIRuntime interface {
 	// has completed, as one might expect. The attach session will remain
 	// running, in a goroutine that will return via the chan error in the
 	// return signature.
-	ExecContainer(ctr *Container, sessionID string, options *ExecOptions, streams *define.AttachStreams) (int, chan error, error)
+	// newSize resizes the tty to this size before the process is started, must be nil if the exec session has no tty
+	ExecContainer(ctr *Container, sessionID string, options *ExecOptions, streams *define.AttachStreams, newSize *define.TerminalSize) (int, chan error, error)
 	// ExecContainerHTTP executes a command in a running container and
 	// attaches its standard streams to a provided hijacked HTTP session.
 	// Maintains the same invariants as ExecContainer (returns on session
 	// start, with a goroutine running in the background to handle attach).
 	// The HTTP attach itself maintains the same invariants as HTTPAttach.
-	ExecContainerHTTP(ctr *Container, sessionID string, options *ExecOptions, r *http.Request, w http.ResponseWriter, streams *HTTPAttachStreams, cancel <-chan bool, hijackDone chan<- bool, holdConnOpen <-chan bool) (int, chan error, error)
+	// newSize resizes the tty to this size before the process is started, must be nil if the exec session has no tty
+	ExecContainerHTTP(ctr *Container, sessionID string, options *ExecOptions, r *http.Request, w http.ResponseWriter,
+		streams *HTTPAttachStreams, cancel <-chan bool, hijackDone chan<- bool, holdConnOpen <-chan bool, newSize *define.TerminalSize) (int, chan error, error)
 	// ExecContainerDetached executes a command in a running container, but
 	// does not attach to it. Returns the PID of the exec session and an
 	// error (if starting the exec session failed)
diff --git a/libpod/oci_attach_linux.go b/libpod/oci_attach_linux.go
index b5040de3e..de435b58a 100644
--- a/libpod/oci_attach_linux.go
+++ b/libpod/oci_attach_linux.go
@@ -94,17 +94,18 @@ func (c *Container) attach(streams *define.AttachStreams, keys string, resize <-
 //    this ensures attachToExec gets all of the output of the called process
 //  conmon will then send the exit code of the exec process, or an error in the exec session
 // startFd must be the input side of the fd.
+// newSize resizes the tty to this size before the process is started, must be nil if the exec session has no tty
 //   conmon will wait to start the exec session until the parent process has setup the console socket.
 //   Once attachToExec successfully attaches to the console socket, the child conmon process responsible for calling runtime exec
 //     will read from the output side of start fd, thus learning to start the child process.
 // Thus, the order goes as follow:
 // 1. conmon parent process sets up its console socket. sends on attachFd
-// 2. attachToExec attaches to the console socket after reading on attachFd
+// 2. attachToExec attaches to the console socket after reading on attachFd and resizes the tty
 // 3. child waits on startFd for attachToExec to attach to said console socket
 // 4. attachToExec sends on startFd, signalling it has attached to the socket and child is ready to go
 // 5. child receives on startFd, runs the runtime exec command
 // attachToExec is responsible for closing startFd and attachFd
-func (c *Container) attachToExec(streams *define.AttachStreams, keys *string, sessionID string, startFd, attachFd *os.File) error {
+func (c *Container) attachToExec(streams *define.AttachStreams, keys *string, sessionID string, startFd, attachFd *os.File, newSize *define.TerminalSize) error {
 	if !streams.AttachOutput && !streams.AttachError && !streams.AttachInput {
 		return errors.Wrapf(define.ErrInvalidArg, "must provide at least one stream to attach to")
 	}
@@ -137,6 +138,14 @@ func (c *Container) attachToExec(streams *define.AttachStreams, keys *string, se
 		return err
 	}
 
+	// resize before we start the container process
+	if newSize != nil {
+		err = c.ociRuntime.ExecAttachResize(c, sessionID, *newSize)
+		if err != nil {
+			logrus.Warn("resize failed", err)
+		}
+	}
+
 	// 2: then attach
 	conn, err := openUnixSocket(sockPath)
 	if err != nil {
diff --git a/libpod/oci_conmon_exec_linux.go b/libpod/oci_conmon_exec_linux.go
index 76338b86c..09d3d1833 100644
--- a/libpod/oci_conmon_exec_linux.go
+++ b/libpod/oci_conmon_exec_linux.go
@@ -25,7 +25,7 @@ import (
 )
 
 // ExecContainer executes a command in a running container
-func (r *ConmonOCIRuntime) ExecContainer(c *Container, sessionID string, options *ExecOptions, streams *define.AttachStreams) (int, chan error, error) {
+func (r *ConmonOCIRuntime) ExecContainer(c *Container, sessionID string, options *ExecOptions, streams *define.AttachStreams, newSize *define.TerminalSize) (int, chan error, error) {
 	if options == nil {
 		return -1, nil, errors.Wrapf(define.ErrInvalidArg, "must provide an ExecOptions struct to ExecContainer")
 	}
@@ -68,7 +68,7 @@ func (r *ConmonOCIRuntime) ExecContainer(c *Container, sessionID string, options
 	attachChan := make(chan error)
 	go func() {
 		// attachToExec is responsible for closing pipes
-		attachChan <- c.attachToExec(streams, options.DetachKeys, sessionID, pipes.startPipe, pipes.attachPipe)
+		attachChan <- c.attachToExec(streams, options.DetachKeys, sessionID, pipes.startPipe, pipes.attachPipe, newSize)
 		close(attachChan)
 	}()
 
@@ -83,7 +83,8 @@ func (r *ConmonOCIRuntime) ExecContainer(c *Container, sessionID string, options
 
 // ExecContainerHTTP executes a new command in an existing container and
 // forwards its standard streams over an attach
-func (r *ConmonOCIRuntime) ExecContainerHTTP(ctr *Container, sessionID string, options *ExecOptions, req *http.Request, w http.ResponseWriter, streams *HTTPAttachStreams, cancel <-chan bool, hijackDone chan<- bool, holdConnOpen <-chan bool) (int, chan error, error) {
+func (r *ConmonOCIRuntime) ExecContainerHTTP(ctr *Container, sessionID string, options *ExecOptions, req *http.Request, w http.ResponseWriter,
+	streams *HTTPAttachStreams, cancel <-chan bool, hijackDone chan<- bool, holdConnOpen <-chan bool, newSize *define.TerminalSize) (int, chan error, error) {
 	if streams != nil {
 		if !streams.Stdin && !streams.Stdout && !streams.Stderr {
 			return -1, nil, errors.Wrapf(define.ErrInvalidArg, "must provide at least one stream to attach to")
@@ -133,7 +134,7 @@ func (r *ConmonOCIRuntime) ExecContainerHTTP(ctr *Container, sessionID string, o
 	conmonPipeDataChan := make(chan conmonPipeData)
 	go func() {
 		// attachToExec is responsible for closing pipes
-		attachChan <- attachExecHTTP(ctr, sessionID, req, w, streams, pipes, detachKeys, options.Terminal, cancel, hijackDone, holdConnOpen, execCmd, conmonPipeDataChan, ociLog)
+		attachChan <- attachExecHTTP(ctr, sessionID, req, w, streams, pipes, detachKeys, options.Terminal, cancel, hijackDone, holdConnOpen, execCmd, conmonPipeDataChan, ociLog, newSize)
 		close(attachChan)
 	}()
 
@@ -486,7 +487,7 @@ func (r *ConmonOCIRuntime) startExec(c *Container, sessionID string, options *Ex
 }
 
 // Attach to a container over HTTP
-func attachExecHTTP(c *Container, sessionID string, r *http.Request, w http.ResponseWriter, streams *HTTPAttachStreams, pipes *execPipes, detachKeys []byte, isTerminal bool, cancel <-chan bool, hijackDone chan<- bool, holdConnOpen <-chan bool, execCmd *exec.Cmd, conmonPipeDataChan chan<- conmonPipeData, ociLog string) (deferredErr error) {
+func attachExecHTTP(c *Container, sessionID string, r *http.Request, w http.ResponseWriter, streams *HTTPAttachStreams, pipes *execPipes, detachKeys []byte, isTerminal bool, cancel <-chan bool, hijackDone chan<- bool, holdConnOpen <-chan bool, execCmd *exec.Cmd, conmonPipeDataChan chan<- conmonPipeData, ociLog string, newSize *define.TerminalSize) (deferredErr error) {
 	// NOTE: As you may notice, the attach code is quite complex.
 	// Many things happen concurrently and yet are interdependent.
 	// If you ever change this function, make sure to write to the
@@ -524,6 +525,14 @@ func attachExecHTTP(c *Container, sessionID string, r *http.Request, w http.Resp
 		return err
 	}
 
+	// resize before we start the container process
+	if newSize != nil {
+		err = c.ociRuntime.ExecAttachResize(c, sessionID, *newSize)
+		if err != nil {
+			logrus.Warn("resize failed", err)
+		}
+	}
+
 	// 2: then attach
 	conn, err := openUnixSocket(sockPath)
 	if err != nil {
diff --git a/libpod/oci_missing.go b/libpod/oci_missing.go
index 10526f368..fcf2ffca8 100644
--- a/libpod/oci_missing.go
+++ b/libpod/oci_missing.go
@@ -119,12 +119,13 @@ func (r *MissingRuntime) AttachResize(ctr *Container, newSize define.TerminalSiz
 }
 
 // ExecContainer is not available as the runtime is missing
-func (r *MissingRuntime) ExecContainer(ctr *Container, sessionID string, options *ExecOptions, streams *define.AttachStreams) (int, chan error, error) {
+func (r *MissingRuntime) ExecContainer(ctr *Container, sessionID string, options *ExecOptions, streams *define.AttachStreams, newSize *define.TerminalSize) (int, chan error, error) {
 	return -1, nil, r.printError()
 }
 
 // ExecContainerHTTP is not available as the runtime is missing
-func (r *MissingRuntime) ExecContainerHTTP(ctr *Container, sessionID string, options *ExecOptions, req *http.Request, w http.ResponseWriter, streams *HTTPAttachStreams, cancel <-chan bool, hijackDone chan<- bool, holdConnOpen <-chan bool) (int, chan error, error) {
+func (r *MissingRuntime) ExecContainerHTTP(ctr *Container, sessionID string, options *ExecOptions, req *http.Request, w http.ResponseWriter,
+	streams *HTTPAttachStreams, cancel <-chan bool, hijackDone chan<- bool, holdConnOpen <-chan bool, newSize *define.TerminalSize) (int, chan error, error) {
 	return -1, nil, r.printError()
 }