add agent wrapper

main.go

@@ -4,6 +4,10 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"os/exec"
+	"os/signal"
+	"strings"
+	"syscall"
 )
 
 func main() {
@@ -40,6 +44,7 @@ func main() {
 			fmt.Println("Error:", err)
 			os.Exit(1)
 		}
+		defer db.Close()
 
 		userPattern := args[1]
 		hostPattern := args[2]
@@ -51,4 +56,74 @@ func main() {
 		}
 		return
 	}
+
+	user, host := parseDestination(args)
+	env := os.Environ()
+
+	if host != "" {
+		db, err := initDB(*dbPath)
+		if err != nil {
+			fmt.Println("Error:", err)
+			os.Exit(1)
+		}
+
+		pemData, err := findKey(db, user, host)
+		if err != nil {
+			fmt.Println("Error:", err)
+			os.Exit(1)
+		}
+
+		db.Close()
+
+		targetName := host
+		if user != "" {
+			targetName = user + "@" + host
+		}
+
+		socketPath, cleanup, err := startEphemeralAgent(pemData, targetName)
+		if err != nil {
+			fmt.Println("Error:", err)
+			os.Exit(1)
+		}
+		defer cleanup()
+
+		newEnv := []string{"SSH_AUTH_SOCK=" + socketPath}
+		for _, e := range env {
+			if !strings.HasPrefix(e, "SSH_AUTH_SOCK=") {
+				newEnv = append(newEnv, e)
+			}
+		}
+		env = newEnv
+	}
+
+	sshPath, err := exec.LookPath("ssh")
+	if err != nil {
+		fmt.Println("Error:", err)
+		os.Exit(1)
+	}
+
+	sshCmd := exec.Command(sshPath, args...)
+	sshCmd.Env = env
+	sshCmd.Stdin = os.Stdin
+	sshCmd.Stdout = os.Stdout
+	sshCmd.Stderr = os.Stderr
+
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
+	go func() {
+		for sig := range c {
+			if sshCmd.Process != nil {
+				sshCmd.Process.Signal(sig)
+			}
+		}
+	}()
+
+	err = sshCmd.Run()
+	if err != nil {
+		fmt.Println("Error:", err)
+		if exitErr, ok := err.(*exec.ExitError); ok {
+			os.Exit(exitErr.ExitCode())
+		}
+		os.Exit(1)
+	}
 }