Port function to get ssh cli options by running ssh binary

tools/cmd/ssh/utils.go

@@ -0,0 +1,82 @@
+// License: GPLv3 Copyright: 2023, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package ssh
+
+import (
+	"fmt"
+	"io"
+	"kitty/tools/utils"
+	"os/exec"
+	"strings"
+	"sync"
+)
+
+var _ = fmt.Print
+
+var ssh_options map[string]string
+var query_ssh_for_options_once sync.Once
+
+func get_ssh_options() {
+	defer func() {
+		if ssh_options == nil {
+			ssh_options = map[string]string{
+				"4": "", "6": "", "A": "", "a": "", "C": "", "f": "", "G": "", "g": "", "K": "", "k": "",
+				"M": "", "N": "", "n": "", "q": "", "s": "", "T": "", "t": "", "V": "", "v": "", "X": "",
+				"x": "", "Y": "", "y": "", "B": "bind_interface", "b": "bind_address", "c": "cipher_spec",
+				"D": "[bind_address:]port", "E": "log_file", "e": "escape_char", "F": "configfile", "I": "pkcs11",
+				"i": "identity_file", "J": "[user@]host[:port]", "L": "address", "l": "login_name", "m": "mac_spec",
+				"O": "ctl_cmd", "o": "option", "p": "port", "Q": "query_option", "R": "address",
+				"S": "ctl_path", "W": "host:port", "w": "local_tun[:remote_tun]",
+			}
+		}
+	}()
+	cmd := exec.Command("ssh")
+	stderr, err := cmd.StderrPipe()
+	if err != nil {
+		return
+	}
+	if err := cmd.Start(); err != nil {
+		return
+	}
+	raw, err := io.ReadAll(stderr)
+	if err != nil {
+		return
+	}
+	text := utils.UnsafeBytesToString(raw)
+	ssh_options = make(map[string]string, 32)
+	for {
+		pos := strings.IndexByte(text, '[')
+		if pos < 0 {
+			break
+		}
+		num := 1
+		epos := pos
+		for num > 0 {
+			epos++
+			switch text[epos] {
+			case '[':
+				num += 1
+			case ']':
+				num -= 1
+			}
+		}
+		q := text[pos+1 : epos]
+		text = text[epos:]
+		if len(q) < 2 || !strings.HasPrefix(q, "-") {
+			continue
+		}
+		opt, desc, found := strings.Cut(q, " ")
+		if found {
+			ssh_options[opt[1:]] = desc
+		} else {
+			for _, ch := range opt[1:] {
+				ssh_options[string(ch)] = ""
+			}
+		}
+	}
+}
+
+func SSHOptions() map[string]string {
+	query_ssh_for_options_once.Do(get_ssh_options)
+	return ssh_options
+}

tools/cmd/ssh/utils_test.go

@@ -0,0 +1,17 @@
+// License: GPLv3 Copyright: 2023, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package ssh
+
+import (
+	"fmt"
+	"testing"
+)
+
+var _ = fmt.Print
+
+func TestGetSSHOptions(t *testing.T) {
+	m := SSHOptions()
+	if m["w"] != "local_tun[:remote_tun]" {
+		t.Fatalf("Unexpected set of SSH options: %#v", m)
+	}
+}