Merge pull request #28957 from shuaiyuanxx/exec-honor-console-size

exec: honor ConsoleSize so the terminal is sized at creation

cmd/podman/containers/exec.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/spf13/cobra"
 	"go.podman.io/common/pkg/completion"
+	"go.podman.io/common/pkg/resize"
 	"go.podman.io/podman/v6/cmd/podman/common"
 	"go.podman.io/podman/v6/cmd/podman/registry"
 	"go.podman.io/podman/v6/cmd/podman/validate"
@@ -18,6 +19,7 @@ import (
 	"go.podman.io/podman/v6/pkg/domain/entities"
 	envLib "go.podman.io/podman/v6/pkg/env"
 	"go.podman.io/podman/v6/pkg/rootless"
+	"golang.org/x/term"
 )
 
 var (
@@ -189,6 +191,16 @@ func exec(cmd *cobra.Command, args []string) error {
 	streams.AttachOutput = true
 	streams.AttachError = true
 
+	// When allocating a TTY, capture the current terminal size up front so the
+	// exec pseudo-terminal is created at the right size, rather than relying on
+	// the asynchronous resize that follows attach. This matters for short-lived
+	// commands that read their window size at startup (e.g. `stty size`).
+	if execOpts.Tty {
+		if w, h, err := term.GetSize(int(os.Stdin.Fd())); err == nil {
+			execOpts.ConsoleSize = &resize.TerminalSize{Width: uint16(w), Height: uint16(h)}
+		}
+	}
+
 	if execNoSession {
 		exitCode, err := registry.ContainerEngine().ContainerExecNoSession(registry.Context(), nameOrID, execOpts, streams)
 		registry.SetExitCode(exitCode)

libpod/container_exec.go

@@ -29,6 +29,12 @@ type ExecConfig struct {
 	Command []string `json:"command"`
 	// Terminal is whether the exec session will allocate a pseudoterminal.
 	Terminal bool `json:"terminal,omitempty"`
+	// ConsoleSize is an optional initial size for the exec session's
+	// pseudoterminal, applied at creation when Terminal is true. This lets a
+	// one-shot exec read the correct window size immediately instead of
+	// relying on an asynchronous resize that may arrive after the process has
+	// already started.
+	ConsoleSize *resize.TerminalSize `json:"consoleSize,omitempty"`
 	// AttachStdin is whether the STDIN stream will be forwarded to the exec
 	// session's first process when attaching. Only available if Terminal is
 	// false.
@@ -1180,6 +1186,7 @@ func prepareForExec(c *Container, session *ExecSession) (*ExecOptions, error) {
 	opts.ExitCommand = session.Config.ExitCommand
 	opts.ExitCommandDelay = session.Config.ExitCommandDelay
 	opts.Privileged = session.Config.Privileged
+	opts.ConsoleSize = session.Config.ConsoleSize
 
 	return opts, nil
 }

libpod/oci.go

@@ -201,6 +201,9 @@ type ExecOptions struct {
 	Env map[string]string
 	// Terminal is whether to create a new TTY for the exec session.
 	Terminal bool
+	// ConsoleSize is an optional initial size for the exec session's TTY,
+	// applied at creation when Terminal is true.
+	ConsoleSize *resize.TerminalSize
 	// Cwd is the working directory for the executed command. If unset, the
 	// working directory of the container will be used.
 	Cwd string

libpod/oci_conmon_exec_common.go

@@ -704,6 +704,16 @@ func (c *Container) prepareProcessExec(options *ExecOptions, env []string, sessi
 	pspec.Terminal = false
 	if options.Terminal {
 		pspec.Terminal = true
+		// Size the exec PTY at creation so the process reads the correct
+		// window size immediately. Without this the PTY starts at 0x0 and is
+		// only corrected by an asynchronous resize, which can arrive after a
+		// one-shot process has already read its size.
+		if options.ConsoleSize != nil {
+			pspec.ConsoleSize = &spec.Box{
+				Height: uint(options.ConsoleSize.Height),
+				Width:  uint(options.ConsoleSize.Width),
+			}
+		}
 	}
 	if len(env) > 0 {
 		pspec.Env = append(pspec.Env, env...)

pkg/api/handlers/compat/exec.go

@@ -42,6 +42,14 @@ func ExecCreateHandler(w http.ResponseWriter, r *http.Request) {
 	libpodConfig := new(libpod.ExecConfig)
 	libpodConfig.Command = input.Cmd
 	libpodConfig.Terminal = input.Tty
+	// Preserve the requested initial terminal size so the exec PTY can be sized
+	// at creation (docker sends ConsoleSize as [height, width]).
+	if input.ConsoleSize != nil {
+		libpodConfig.ConsoleSize = &resize.TerminalSize{
+			Height: uint16(input.ConsoleSize[0]),
+			Width:  uint16(input.ConsoleSize[1]),
+		}
+	}
 	libpodConfig.AttachStdin = input.AttachStdin
 	libpodConfig.AttachStderr = input.AttachStderr
 	libpodConfig.AttachStdout = input.AttachStdout

pkg/domain/entities/containers.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	nettypes "go.podman.io/common/libnetwork/types"
+	"go.podman.io/common/pkg/resize"
 	imageTypes "go.podman.io/image/v5/types"
 	"go.podman.io/podman/v6/libpod/define"
 	"go.podman.io/podman/v6/pkg/domain/entities/types"
@@ -283,6 +284,7 @@ type ContainerLogsOptions struct {
 // a container
 type ExecOptions struct {
 	Cmd         []string
+	ConsoleSize *resize.TerminalSize
 	DetachKeys  string
 	Envs        map[string]string
 	Interactive bool

pkg/domain/infra/abi/containers.go

@@ -890,6 +890,13 @@ func makeExecConfig(options entities.ExecOptions, rt *libpod.Runtime, noSession
 	execConfig.PreserveFD = options.PreserveFD
 	execConfig.AttachStdin = options.Interactive
 
+	// Size the exec terminal at creation so a process that reads its window size
+	// at startup (e.g. `stty size`) observes the right value, rather than relying
+	// on the asynchronous resize that follows attach.
+	if options.Tty {
+		execConfig.ConsoleSize = options.ConsoleSize
+	}
+
 	// Only set up exit command for regular exec sessions, not no-session mode
 	if !noSession {
 		// Make an exit command

pkg/domain/infra/tunnel/containers.go

@@ -618,6 +618,12 @@ func makeExecConfig(options entities.ExecOptions) *handlers.ExecCreateConfig {
 	createConfig.Env = env
 	createConfig.WorkingDir = options.WorkDir
 	createConfig.Cmd = options.Cmd
+	// Size the exec terminal at creation, mirroring the local path, so the
+	// service does not have to rely on the asynchronous resize that follows
+	// attach. ConsoleSize is ordered [height, width].
+	if options.Tty && options.ConsoleSize != nil {
+		createConfig.ConsoleSize = &[2]uint{uint(options.ConsoleSize.Height), uint(options.ConsoleSize.Width)}
+	}
 
 	return createConfig
 }

test/system/450-interactive.bats

@@ -70,14 +70,15 @@ function teardown() {
 
     run_podman rm -t 0 -f mystty
 
-    # FIXME: the checks below are flaking a lot (see #10710).
+    # The same must hold for podman exec. The exec pseudo-terminal is now sized
+    # at creation (honoring the requested ConsoleSize), so stty reads the right
+    # dimensions immediately instead of racing the asynchronous resize that
+    # previously followed attach (see #10710).
+    run_podman run -d --name mystty $IMAGE top
+    run_podman exec -it mystty stty size <$PODMAN_TEST_PTY
+    is "$output" "$rows $cols$CR" "stty under podman exec reads the correct dimensions"
 
-    # check that the same works for podman exec
-#    run_podman run -d --name mystty $IMAGE top
-#    run_podman exec -it mystty stty size <$PODMAN_TEST_PTY
-#    is "$output" "$rows $cols" "stty under podman exec reads the correct dimensions"
-#
-#    run_podman rm -t 0 -f mystty
+    run_podman rm -t 0 -f mystty
 }