Add support for RemoteCommand option in kitten ssh

Author: zzhaolei

kittens/ssh/main.go

@@ -10,7 +10,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"github.com/kovidgoyal/kitty"
 	"io"
 	"io/fs"
 	"maps"
@@ -28,6 +27,8 @@ 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 +178,7 @@ 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 +410,18 @@ 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 +431,9 @@ 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 +451,8 @@ 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 +486,7 @@ 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 +620,7 @@ 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 *SSHConfig) (rc int, err error) {
 	go shell_integration.Data()
 	go RelevantKittyOpts()
 	defer func() {
@@ -610,11 +630,14 @@ func run_ssh(ssh_args, server_args, found_extra_args []string) (rc int, err erro
 		}
 	}()
 	cmd := append([]string{SSHExe()}, ssh_args...)
-	cd := connection_data{remote_args: server_args[1:]}
+	cd := connection_data{remote_args: server_args[1:], ssh_config: ssh_config}
 	hostname := server_args[0]
 	if len(cd.remote_args) == 0 {
 		cmd = append(cmd, "-t")
 	}
+	if cd.ssh_config != nil && cd.ssh_config.RemoteCommand != "" {
+		cmd = append(cmd, "-o", "RemoteCommand=none")
+	}
 	insertion_point := len(cmd)
 	cmd = append(cmd, "--", hostname)
 	uname, hostname_for_match := get_destination(hostname)
@@ -833,13 +856,17 @@ 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())
 	}
+	ssh_config, err := LoadSSHConfig(server_args[0])
+	if err != nil {
+		return 1, err
+	}
 	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)
 }
 
 func EntryPoint(parent *cli.Command) {

kittens/ssh/utils.go

@@ -3,6 +3,7 @@
 package ssh
 
 import (
+	"bufio"
 	"bytes"
 	"fmt"
 	"os/exec"
@@ -194,6 +195,40 @@ func ParseSSHArgs(args []string, extra_args ...string) (ssh_args []string, serve
 	return
 }
 
+type SSHConfig struct {
+	RemoteCommand string
+}
+
+func LoadSSHConfig(hostname string) (config *SSHConfig, err error) {
+	cmd_args := []string{SSHExe(), hostname, "-G"}
+	cmd := exec.Command(cmd_args[0], cmd_args[1:]...)
+	var stdout, stderr bytes.Buffer
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+	_ = cmd.Run()
+
+	text := stdout.String()
+	scanner := bufio.NewScanner(strings.NewReader(text))
+
+	config = &SSHConfig{}
+	for scanner.Scan() {
+		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
+			}
+		}
+	}
+	return config, nil
+}
+
 type SSHVersion struct{ Major, Minor int }
 
 func (self SSHVersion) SupportsAskpassRequire() bool {

shell-integration/ssh/bootstrap.py

@@ -321,6 +321,11 @@ def main():
         os.environ.pop('KITTY_SHELL_INTEGRATION', None)
         cmd = base64.standard_b64decode(exec_cmd).decode('utf-8')
         exec_with_better_error(login_shell, os.path.basename(login_shell), '-c', cmd)
+    remote_cmd = b'REMOTE_CMD'
+    if remote_cmd:
+        os.environ.pop('KITTY_SHELL_INTEGRATION', None)
+        cmd = base64.standard_b64decode(remote_cmd).decode('utf-8')
+        exec_with_better_error(login_shell, os.path.basename(login_shell), '-c', cmd)
     TEST_SCRIPT  # noqa
     if ksi and 'no-rc' not in ksi:
         exec_with_shell_integration()

shell-integration/ssh/bootstrap.sh

@@ -158,6 +158,8 @@ prepare_for_exec
 # If a command was passed to SSH execute it here
 EXEC_CMD
 
+REMOTE_CMD
+
 # Used in the tests
 TEST_SCRIPT