Move SSH askpass implementation into kitten

tools/cmd/ssh/askpass.go

@@ -0,0 +1,118 @@
+// License: GPLv3 Copyright: 2023, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package ssh
+
+import (
+	"encoding/binary"
+	"encoding/json"
+	"fmt"
+	"os"
+	"strings"
+	"time"
+
+	"kitty/tools/cli"
+	"kitty/tools/tty"
+	"kitty/tools/utils/shm"
+)
+
+var _ = fmt.Print
+
+func fatal(err error) {
+	cli.ShowError(err)
+	os.Exit(1)
+}
+
+func trigger_ask(name string) {
+	term, err := tty.OpenControllingTerm()
+	if err != nil {
+		fatal(err)
+	}
+	defer term.Close()
+	_, err = term.WriteString("\x1bP@kitty-ask|" + name + "\x1b\\")
+	if err != nil {
+		fatal(err)
+	}
+
+}
+
+func RunSSHAskpass() {
+	msg := os.Args[len(os.Args)-1]
+	prompt := os.Getenv("SSH_ASKPASS_PROMPT")
+	is_confirm := prompt == "confirm"
+	q_type := "get_line"
+	if is_confirm {
+		q_type = "confirm"
+	}
+	is_fingerprint_check := strings.Contains(msg, "(yes/no/[fingerprint])")
+	q := map[string]any{
+		"message":     msg,
+		"type":        q_type,
+		"is_password": !is_fingerprint_check,
+	}
+	data, err := json.Marshal(q)
+	if err != nil {
+		fatal(err)
+	}
+	shm, err := shm.CreateTemp("askpass-*", uint64(len(data)+32))
+	if err != nil {
+		fatal(fmt.Errorf("Failed to create SHM file with error: %w", err))
+	}
+	defer shm.Close()
+	defer shm.Unlink()
+
+	shm.Slice()[0] = 0
+	binary.BigEndian.PutUint32(shm.Slice()[1:], uint32(len(data)))
+	copy(shm.Slice()[5:], data)
+	err = shm.Flush()
+	if err != nil {
+		fatal(fmt.Errorf("Failed to flush SHM file with error: %w", err))
+	}
+	trigger_ask(shm.Name())
+	buf := []byte{0}
+	for {
+		time.Sleep(50 * time.Millisecond)
+		_, err = shm.Seek(0, os.SEEK_SET)
+		if err != nil {
+			fatal(fmt.Errorf("Failed to seek into SHM file while waiting for response with error: %w", err))
+		}
+		_, err = shm.Read(buf)
+		if err != nil {
+			fatal(fmt.Errorf("Failed to read from SHM file while waiting for response with error: %w", err))
+		}
+		if buf[0] == 1 {
+			break
+		}
+	}
+	data, err = shm.ReadWithSize()
+	if err != nil {
+		fatal(fmt.Errorf("Failed to read response data from SHM file with error: %w", err))
+	}
+	response := ""
+	if is_confirm {
+		var ok bool
+		err = json.Unmarshal(data, &ok)
+		if err != nil {
+			fatal(fmt.Errorf("Failed to parse response data: %#v with error: %w", string(data), err))
+		}
+		response = "no"
+		if ok {
+			response = "yes"
+		}
+	} else {
+		err = json.Unmarshal(data, &response)
+		if err != nil {
+			fatal(fmt.Errorf("Failed to parse response data: %#v with error: %w", string(data), err))
+		}
+		if is_fingerprint_check {
+			response = strings.ToLower(response)
+			if response == "y" {
+				response = "yes"
+			} else if response == "n" {
+				response = "no"
+			}
+		}
+	}
+	if response != "" {
+		fmt.Println(response)
+	}
+}