Abstract cross-platform terminal syscalls

Change-Id: I409e93a6298d6c45ee96d47e65e4abef6e4fe503
coder · cmoog · Jul 28, 2020 · Jul 27, 2020 · Jul 28, 2020 · Jul 28, 2020
commit 6fc2c8ccaa66e128a0bc5932cb965643724b2ade
diff --git a/cmd/coder/resize_unix.go b/cmd/coder/resize_unix.go
diff --git a/cmd/coder/resize_windows.go b/cmd/coder/resize_windows.go
diff --git a/cmd/coder/shell.go b/cmd/coder/shell.go
@@ -17,6 +17,7 @@ import (
 	"go.coder.com/flog"
 
 	"cdr.dev/coder-cli/internal/activity"
+	"cdr.dev/coder-cli/internal/xterminal"
 	"cdr.dev/wsep"
 )
 
@@ -31,49 +32,10 @@ func (cmd *shellCmd) Spec() cli.CommandSpec {
 	}
 }
 
-func enableTerminal(fd int) (restore func(), err error) {
-	state, err := terminal.MakeRaw(fd)
-	if err != nil {
-		return restore, xerrors.Errorf("make raw term: %w", err)
-	}
-	return func() {
-		err := terminal.Restore(fd, state)
-		if err != nil {
-			flog.Error("restore term state: %v", err)
-		}
-	}, nil
-}
-
 type resizeEvent struct {
 	height, width uint16
 }
 
-func (s resizeEvent) equal(s2 *resizeEvent) bool {
-	if s2 == nil {
-		return false
-	}
-	return s.height == s2.height && s.width == s2.width
-}
-
-func sendResizeEvents(ctx context.Context, termfd int, process wsep.Process) {
-	events := resizeEvents(ctx, termfd)
-
-	// Limit the frequency of resizes to prevent a stuttering effect.
-	resizeLimiter := rate.NewLimiter(rate.Every(time.Millisecond*100), 1)
-	for {
-		select {
-		case newsize := <-events:
-			err := process.Resize(ctx, newsize.height, newsize.width)
-			if err != nil {
-				return
-			}
-			_ = resizeLimiter.Wait(ctx)
-		case <-ctx.Done():
-			return
-		}
-	}
-}
-
 func (cmd *shellCmd) Run(fl *pflag.FlagSet) {
 	if len(fl.Args()) < 1 {
 		exitUsage(fl)
@@ -101,21 +63,46 @@ func (cmd *shellCmd) Run(fl *pflag.FlagSet) {
 	}
 }
 
+func sendResizeEvents(ctx context.Context, termfd uintptr, process wsep.Process) {
+	events := xterminal.ResizeEvents(ctx, termfd)
+
+	// Limit the frequency of resizes to prevent a stuttering effect.
+	resizeLimiter := rate.NewLimiter(rate.Every(time.Millisecond*100), 1)
+	for {
+		select {
+		case newsize := <-events:
+			err := process.Resize(ctx, newsize.Height, newsize.Width)
+			if err != nil {
+				return
+			}
+			_ = resizeLimiter.Wait(ctx)
+		case <-ctx.Done():
+			return
+		}
+	}
+}
+
 func runCommand(ctx context.Context, envName string, command string, args []string) error {
 	var (
 		entClient = requireAuth()
 		env       = findEnv(entClient, envName)
 	)
 
-	termfd := int(os.Stdin.Fd())
+	termfd := os.Stdout.Fd()
 
-	tty := terminal.IsTerminal(termfd)
+	tty := terminal.IsTerminal(int(termfd))
 	if tty {
-		restore, err := enableTerminal(termfd)
+		stdinState, err := xterminal.MakeRaw(os.Stdin.Fd())
+		if err != nil {
+			return err
+		}
+		defer xterminal.Restore(os.Stdin.Fd(), stdinState)
+
+		stdoutState, err := xterminal.MakeOutputRaw(os.Stdout.Fd())
 		if err != nil {
 			return err
 		}
-		defer restore()
+		defer xterminal.Restore(os.Stdout.Fd(), stdoutState)
 	}
 
 	ctx, cancel := context.WithCancel(ctx)
@@ -127,13 +114,22 @@ func runCommand(ctx context.Context, envName string, command string, args []stri
 	}
 	go heartbeat(ctx, conn, 15*time.Second)
 
+	var cmdEnv []string
+	if tty {
+		term := os.Getenv("TERM")
+		if term == "" {
+			term = "xterm"
+		}
+		cmdEnv = append(cmdEnv, "TERM="+term)
+	}
+
 	execer := wsep.RemoteExecer(conn)
 	process, err := execer.Start(ctx, wsep.Command{
 		Command: command,
 		Args:    args,
 		TTY:     tty,
 		Stdin:   true,
-		Env:     []string{"TERM=" + os.Getenv("TERM")},
+		Env:     cmdEnv,
 	})
 	if err != nil {
 		return err

diff --git a/go.mod b/go.mod
@@ -3,7 +3,7 @@ module cdr.dev/coder-cli
 go 1.14
 
 require (
-	cdr.dev/wsep v0.0.0-20200727194627-13ef1f8df965
+	cdr.dev/wsep v0.0.0-20200728013649-82316a09813f
 	github.com/fatih/color v1.9.0 // indirect
 	github.com/gorilla/websocket v1.4.1
 	github.com/kirsle/configdir v0.0.0-20170128060238-e45d2f54772f

diff --git a/go.sum b/go.sum
@@ -1,7 +1,7 @@
 cdr.dev/slog v1.3.0 h1:MYN1BChIaVEGxdS7I5cpdyMC0+WfJfK8BETAfzfLUGQ=
 cdr.dev/slog v1.3.0/go.mod h1:C5OL99WyuOK8YHZdYY57dAPN1jK2WJlCdq2VP6xeQns=
-cdr.dev/wsep v0.0.0-20200727194627-13ef1f8df965 h1:zFpraxgmcgX60oWFs8r1moWFMJ0x945t4moxNb6fjJ8=
-cdr.dev/wsep v0.0.0-20200727194627-13ef1f8df965/go.mod h1:N20HJdMn6q9NG7sjxL4uYdBQBGOf8/6psfdMyuJnYw8=
+cdr.dev/wsep v0.0.0-20200728013649-82316a09813f h1:WnTUINBwXE11xjp5nTVt+H2qB2/KEymos1jKMcppG9U=
+cdr.dev/wsep v0.0.0-20200728013649-82316a09813f/go.mod h1:2VKClUml3gfmLez0gBxTJIjSKszpQotc2ZqPdApfK/Y=
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 cloud.google.com/go v0.38.0/go.mod h1:990N+gfupTy94rShfmMCWGDn0LpTmnzTp2qbd1dvSRU=
@@ -107,8 +107,6 @@ github.com/gorilla/websocket v1.4.1/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/ad
 github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
-github.com/iamacarpet/go-winpty v1.0.2 h1:jwPVTYrjAHZx6Mcm6K5i9G4opMp5TblEHH5EQCl/Gzw=
-github.com/iamacarpet/go-winpty v1.0.2/go.mod h1:/GHKJicG/EVRQIK1IQikMYBakBkhj/3hTjLgdzYsmpI=
 github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
 github.com/json-iterator/go v1.1.9 h1:9yzud/Ht36ygwatGx56VwCZtlI/2AD15T1X2sjSuGns=
 github.com/json-iterator/go v1.1.9/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=

diff --git a/internal/xterminal/doc.go b/internal/xterminal/doc.go
@@ -0,0 +1,13 @@
+// Package xterminal provides functions to change termios or console attributes
+// and restore them later on. It supports Unix and Windows.
+//
+// This does the same thing as x/crypto/ssh/terminal on Linux. On Windows, it
+// sets the same console modes as the terminal package but also sets
+// `ENABLE_VIRTUAL_TERMINAL_INPUT` and `ENABLE_VIRTUAL_TERMINAL_PROCESSING` to
+// allow for VT100 sequences in the console. This is important, otherwise Linux
+// apps (with colors or ncurses) that are run through SSH or wsep get
+// garbled in a Windows console.
+//
+// More details can be found out about Windows console modes here:
+// https://docs.microsoft.com/en-us/windows/console/setconsolemode
+package xterminal
diff --git a/internal/xterminal/terminal.go b/internal/xterminal/terminal.go
@@ -0,0 +1,71 @@
+// +build !windows
+
+package xterminal
+
+import (
+	"context"
+	"os"
+	"os/signal"
+
+	"golang.org/x/crypto/ssh/terminal"
+	"golang.org/x/sys/unix"
+)
+
+// State differs per-platform.
+type State struct {
+	s *terminal.State
+}
+
+// MakeRaw sets the terminal to raw.
+func MakeRaw(fd uintptr) (*State, error) {
+	s, err := terminal.MakeRaw(int(fd))
+	return &State{s}, err
+}
+
+// MakeOutputRaw does nothing on non-Windows platforms.
+func MakeOutputRaw(fd uintptr) (*State, error) {
+	return nil, nil
+}
+
+// Restore terminal back to original state.
+func Restore(fd uintptr, state *State) error {
+	if state == nil {
+		return nil
+	}
+
+	return terminal.Restore(int(fd), state.s)
+}
+
+// ColorEnabled returns true on Linux if handle is a terminal.
+func ColorEnabled(fd uintptr) (bool, error) {
+	return terminal.IsTerminal(int(fd)), nil
+}
+
+type ResizeEvent struct {
+	Height, Width uint16
+}
+
+// ResizeEvents sends terminal resize events
+func ResizeEvents(ctx context.Context, termfd uintptr) chan ResizeEvent {
+	sigs := make(chan os.Signal, 16)
+	signal.Notify(sigs, unix.SIGWINCH)
+
+	events := make(chan ResizeEvent)
+
+	go func() {
+		for ctx.Err() == nil {
+			width, height, err := terminal.GetSize(int(termfd))
+			if err != nil {
+				return
+			}
+			events <- ResizeEvent{
+				Height: uint16(height),
+				Width:  uint16(width),
+			}
+
+			<-sigs
+		}
+	}()
+
+	return events
+}