Merge branch 'feature/support-ssh-remote-command' of https://github.com/zzhaolei/kitty

Fixes #3988

kittens/ssh/main.go

@@ -6,11 +6,11 @@ import (
 	"archive/tar"
 	"bytes"
 	"compress/gzip"
+	"context"
 	"encoding/base64"
 	"encoding/json"
 	"errors"
 	"fmt"
-	"github.com/kovidgoyal/kitty"
 	"io"
 	"io/fs"
 	"maps"
@@ -28,6 +28,8 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/kovidgoyal/kitty"
+
 	"github.com/kovidgoyal/go-shm"
 	"github.com/kovidgoyal/kitty/tools/cli"
 	"github.com/kovidgoyal/kitty/tools/themes"
@@ -177,6 +179,7 @@ func set_askpass(hostname_for_match, uname string, overrides []string) (need_to_
 type connection_data struct {
 	remote_args        []string
 	host_opts          *Config
+	ssh_config         *SSHConfig
 	hostname_for_match string
 	username           string
 	echo_on            bool
@@ -408,6 +411,18 @@ func prepare_exec_cmd(cd *connection_data) string {
 	return "unset KITTY_SHELL_INTEGRATION; exec \"$login_shell\" -c '" + strings.Join(args, " ") + "'"
 }
 
+func prepare_remote_cmd(cd *connection_data) string {
+	if cd.ssh_config == nil || cd.ssh_config.RemoteCommand == "" {
+		return ""
+	}
+
+	remote_command := cd.ssh_config.RemoteCommand
+	if cd.script_type == "py" {
+		return base64.RawStdEncoding.EncodeToString(utils.UnsafeStringToBytes(remote_command))
+	}
+	return remote_command
+}
+
 var data_shm shm.MMap
 
 func prepare_script(script string, replacements map[string]string) string {
@@ -417,6 +432,9 @@ func prepare_script(script string, replacements map[string]string) string {
 	if _, found := replacements["EXPORT_HOME_CMD"]; !found {
 		replacements["EXPORT_HOME_CMD"] = ""
 	}
+	if _, found := replacements["REMOTE_CMD"]; !found {
+		replacements["REMOTE_CMD"] = ""
+	}
 	keys := utils.Keys(replacements)
 	for i, key := range keys {
 		keys[i] = "\\b" + key + "\\b"
@@ -434,6 +452,8 @@ func bootstrap_script(cd *connection_data) (err error) {
 	if len(cd.remote_args) > 0 {
 		exec_cmd = prepare_exec_cmd(cd)
 	}
+	remote_cmd := prepare_remote_cmd(cd)
+
 	pw, err := secrets.TokenHex()
 	if err != nil {
 		return err
@@ -467,6 +487,7 @@ func bootstrap_script(cd *connection_data) (err error) {
 	replacements := map[string]string{
 		"EXPORT_HOME_CMD": export_home_cmd,
 		"EXEC_CMD":        exec_cmd,
+		"REMOTE_CMD":      remote_cmd,
 		"TEST_SCRIPT":     cd.test_script,
 	}
 	add_bool := func(ok bool, key string) {
@@ -600,7 +621,7 @@ func change_colors(color_scheme string) (ans string, err error) {
 	return
 }
 
-func run_ssh(ssh_args, server_args, found_extra_args []string) (rc int, err error) {
+func run_ssh(ssh_args, server_args, found_extra_args []string, ssh_config_channel <-chan *SSHConfig) (rc int, err error) {
 	go shell_integration.Data()
 	go RelevantKittyOpts()
 	defer func() {
@@ -757,6 +778,12 @@ func run_ssh(ssh_args, server_args, found_extra_args []string) (rc int, err erro
 		}
 	}
 	defer cleanup()
+	// Receive ssh config
+	ssh_config := <-ssh_config_channel
+	if ssh_config != nil && ssh_config.RemoteCommand != "" {
+		cmd = slices.Insert(cmd, insertion_point, "-o", "RemoteCommand=none")
+	}
+	cd.ssh_config = ssh_config
 	err = get_remote_command(&cd)
 	if err != nil {
 		return 1, err
@@ -833,13 +860,18 @@ func main(cmd *cli.Command, o *Options, args []string) (rc int, err error) {
 	if passthrough {
 		return 1, unix.Exec(SSHExe(), utils.Concat([]string{"ssh"}, ssh_args, server_args), os.Environ())
 	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	ssh_config_channel := ReadSSHConfig(ctx, server_args[0])
+
 	if os.Getenv("KITTY_WINDOW_ID") == "" || os.Getenv("KITTY_PID") == "" {
 		return 1, fmt.Errorf("The SSH kitten is meant to run inside a kitty window")
 	}
 	if !tty.IsTerminal(os.Stdin.Fd()) {
 		return 1, fmt.Errorf("The SSH kitten is meant for interactive use only, STDIN must be a terminal")
 	}
-	return run_ssh(ssh_args, server_args, found_extra_args)
+	return run_ssh(ssh_args, server_args, found_extra_args, ssh_config_channel)
 }
 
 func EntryPoint(parent *cli.Command) {

kittens/ssh/utils.go

@@ -3,7 +3,9 @@
 package ssh
 
 import (
+	"bufio"
 	"bytes"
+	"context"
 	"fmt"
 	"os/exec"
 	"regexp"
@@ -194,6 +196,59 @@ func ParseSSHArgs(args []string, extra_args ...string) (ssh_args []string, serve
 	return
 }
 
+type SSHConfig struct {
+	RemoteCommand string
+}
+
+// ReadSSHConfig Asynchronously read ssh configuration
+func ReadSSHConfig(ctx context.Context, hostname string) <-chan *SSHConfig {
+	ch := make(chan *SSHConfig, 1)
+
+	go func() {
+		defer close(ch)
+
+		cmd_args := []string{SSHExe(), hostname, "-G"}
+		cmd := exec.CommandContext(ctx, cmd_args[0], cmd_args[1:]...)
+		var stdout, stderr bytes.Buffer
+		cmd.Stdout = &stdout
+		cmd.Stderr = &stderr
+		if err := cmd.Run(); err != nil {
+			return
+		}
+
+		text := stdout.String()
+		scanner := bufio.NewScanner(strings.NewReader(text))
+
+		config := &SSHConfig{}
+		for scanner.Scan() {
+			select {
+			case <-ctx.Done():
+				return
+			default:
+			}
+			line := scanner.Text()
+			i := strings.IndexByte(line, ' ')
+			if i <= 0 {
+				continue
+			}
+
+			key, val := line[:i], line[i+1:]
+			switch key {
+			case "remotecommand":
+				if val != "none" {
+					config.RemoteCommand = val
+				}
+			}
+		}
+		select {
+		case <-ctx.Done():
+			return
+		case ch <- config:
+		}
+	}()
+	return ch
+}
+
 type SSHVersion struct{ Major, Minor int }
 
 func (self SSHVersion) SupportsAskpassRequire() bool {