From 904b414fce2fc5bc20ecb1964407eb17fb370e78 Mon Sep 17 00:00:00 2001
From: Hugo Santos <hugo@namespacelabs.com>
Date: Wed, 4 Jun 2025 15:53:35 -0400
Subject: [PATCH] first windows port; no pty support.

---
 cmd/breakpoint/start.go          |  8 +++---
 pkg/execbackground/bg_unix.go    | 14 ++++++++++
 pkg/execbackground/bg_windows.go |  9 +++++++
 pkg/sshd/pty_unix.go             | 44 ++++++++++++++++++++++++++++++++
 pkg/sshd/pty_windows.go          | 15 +++++++++++
 pkg/sshd/sshd.go                 | 13 +---------
 pkg/sshd/winresize.go            | 20 ---------------
 7 files changed, 86 insertions(+), 37 deletions(-)
 create mode 100644 pkg/execbackground/bg_unix.go
 create mode 100644 pkg/execbackground/bg_windows.go
 create mode 100644 pkg/sshd/pty_unix.go
 create mode 100644 pkg/sshd/pty_windows.go
 delete mode 100644 pkg/sshd/winresize.go

diff --git a/cmd/breakpoint/start.go b/cmd/breakpoint/start.go
index 5fc321f..5287de3 100644
--- a/cmd/breakpoint/start.go
+++ b/cmd/breakpoint/start.go
@@ -6,13 +6,13 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
-	"syscall"
 	"time"
 
 	"github.com/spf13/cobra"
 	"google.golang.org/protobuf/types/known/emptypb"
-	"namespacelabs.dev/breakpoint/api/private/v1"
+	v1 "namespacelabs.dev/breakpoint/api/private/v1"
 	"namespacelabs.dev/breakpoint/pkg/bcontrol"
+	"namespacelabs.dev/breakpoint/pkg/execbackground"
 	"namespacelabs.dev/breakpoint/pkg/waiter"
 )
 
@@ -35,9 +35,7 @@ func newStartCmd() *cobra.Command {
 
 		procArgs := []string{"wait", "--config", *configPath}
 		proc := exec.Command(os.Args[0], procArgs...)
-		proc.SysProcAttr = &syscall.SysProcAttr{
-			Setsid: true,
-		}
+		execbackground.SetCreateSession(proc)
 
 		if err := proc.Start(); err != nil {
 			return fmt.Errorf("failed to start background process: %w", err)
diff --git a/pkg/execbackground/bg_unix.go b/pkg/execbackground/bg_unix.go
new file mode 100644
index 0000000..beb0b37
--- /dev/null
+++ b/pkg/execbackground/bg_unix.go
@@ -0,0 +1,14 @@
+//go:build !windows
+
+package execbackground
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+func SetCreateSession(cmd *exec.Cmd) {
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		Setsid: true,
+	}
+}
diff --git a/pkg/execbackground/bg_windows.go b/pkg/execbackground/bg_windows.go
new file mode 100644
index 0000000..f530448
--- /dev/null
+++ b/pkg/execbackground/bg_windows.go
@@ -0,0 +1,9 @@
+//go:build windows
+
+package execbackground
+
+import "os/exec"
+
+func SetCreateSession(cmd *exec.Cmd) {
+	panic("not supported")
+}
diff --git a/pkg/sshd/pty_unix.go b/pkg/sshd/pty_unix.go
new file mode 100644
index 0000000..6ac15e4
--- /dev/null
+++ b/pkg/sshd/pty_unix.go
@@ -0,0 +1,44 @@
+//go:build !windows
+
+package sshd
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"syscall"
+	"unsafe"
+
+	"github.com/creack/pty"
+	"github.com/gliderlabs/ssh"
+)
+
+func handlePty(session io.ReadWriter, ptyReq ssh.Pty, winCh <-chan ssh.Window, cmd *exec.Cmd) error {
+	cmd.Env = append(cmd.Env, fmt.Sprintf("TERM=%s", ptyReq.Term))
+	ptyFile, err := pty.Start(cmd)
+	if err != nil {
+		return err
+	}
+
+	defer ptyFile.Close()
+
+	go syncWinSize(ptyFile, winCh)
+	go func() {
+		_, _ = io.Copy(ptyFile, session) // stdin
+	}()
+	_, _ = io.Copy(session, ptyFile) // stdout
+
+	return nil
+}
+
+func syncWinSize(ptyFile *os.File, winCh <-chan ssh.Window) {
+	for win := range winCh {
+		setWinsize(ptyFile, win.Width, win.Height)
+	}
+}
+
+func setWinsize(f *os.File, w, h int) {
+	syscall.Syscall(syscall.SYS_IOCTL, f.Fd(), uintptr(syscall.TIOCSWINSZ),
+		uintptr(unsafe.Pointer(&struct{ h, w, x, y uint16 }{uint16(h), uint16(w), 0, 0})))
+}
diff --git a/pkg/sshd/pty_windows.go b/pkg/sshd/pty_windows.go
new file mode 100644
index 0000000..cedcea8
--- /dev/null
+++ b/pkg/sshd/pty_windows.go
@@ -0,0 +1,15 @@
+//go:build windows
+
+package sshd
+
+import (
+	"errors"
+	"io"
+	"os/exec"
+
+	"github.com/gliderlabs/ssh"
+)
+
+func handlePty(session io.ReadWriter, ptyReq ssh.Pty, winCh <-chan ssh.Window, cmd *exec.Cmd) error {
+	return errors.New("pty not supported in windows")
+}
diff --git a/pkg/sshd/sshd.go b/pkg/sshd/sshd.go
index b337385..67f72d4 100644
--- a/pkg/sshd/sshd.go
+++ b/pkg/sshd/sshd.go
@@ -10,7 +10,6 @@ import (
 	"os/exec"
 	"time"
 
-	"github.com/creack/pty"
 	"github.com/gliderlabs/ssh"
 	"github.com/rs/zerolog"
 	"go.uber.org/atomic"
@@ -96,21 +95,11 @@ func MakeServer(ctx context.Context, opts SSHServerOpts) (*SSHServer, error) {
 					opts.InteractiveMOTD(session)
 				}
 
-				cmd.Env = append(cmd.Env, fmt.Sprintf("TERM=%s", ptyReq.Term))
-				ptyFile, err := pty.Start(cmd)
-				if err != nil {
+				if err := handlePty(session, ptyReq, winCh, cmd); err != nil {
 					sessionLog.Err(err).Msg("pty start failed")
 					session.Exit(1)
 					return
 				}
-
-				defer ptyFile.Close()
-
-				go syncWinSize(ptyFile, winCh)
-				go func() {
-					_, _ = io.Copy(ptyFile, session) // stdin
-				}()
-				_, _ = io.Copy(session, ptyFile) // stdout
 			} else {
 				cmd.Stdout = session
 				cmd.Stderr = session
diff --git a/pkg/sshd/winresize.go b/pkg/sshd/winresize.go
deleted file mode 100644
index 7462d2e..0000000
--- a/pkg/sshd/winresize.go
+++ /dev/null
@@ -1,20 +0,0 @@
-package sshd
-
-import (
-	"os"
-	"syscall"
-	"unsafe"
-
-	"github.com/gliderlabs/ssh"
-)
-
-func syncWinSize(ptyFile *os.File, winCh <-chan ssh.Window) {
-	for win := range winCh {
-		setWinsize(ptyFile, win.Width, win.Height)
-	}
-}
-
-func setWinsize(f *os.File, w, h int) {
-	syscall.Syscall(syscall.SYS_IOCTL, f.Fd(), uintptr(syscall.TIOCSWINSZ),
-		uintptr(unsafe.Pointer(&struct{ h, w, x, y uint16 }{uint16(h), uint16(w), 0, 0})))
-}