add agent wrapper

agent.go

@@ -0,0 +1,77 @@
+package main
+
+import (
+	"fmt"
+	"net"
+	"os"
+	"path/filepath"
+	"syscall"
+
+	"golang.org/x/crypto/ssh"
+	"golang.org/x/crypto/ssh/agent"
+	"golang.org/x/term"
+)
+
+func startEphemeralAgent(pemData []byte, target string) (string, func(), error) {
+	var key interface{}
+	var err error
+
+	key, err = ssh.ParseRawPrivateKey(pemData)
+
+	if err != nil {
+		if _, ok := err.(*ssh.PassphraseMissingError); ok {
+			fmt.Printf("\033[1;32m? Gosh:\033[0m Key for \033[1m%s\033[0m is encrypted. Enter passphrase: ", target)
+			pass, readErr := term.ReadPassword(int(syscall.Stdin))
+			fmt.Println()
+			if readErr != nil {
+				return "", nil, fmt.Errorf("failed to read password: %w", err)
+			}
+
+			key, err = ssh.ParseRawPrivateKeyWithPassphrase(pemData, pass)
+			if err != nil {
+				return "", nil, fmt.Errorf("incorrect passphrase or invalid key: %w", err)
+			}
+		} else {
+			return "", nil, fmt.Errorf("invalid key format: %w", err)
+		}
+	} else {
+		fmt.Printf("Using unencrypted key for %s\n", target)
+	}
+
+	keyring := agent.NewKeyring()
+	addedKey := agent.AddedKey{
+		PrivateKey:   key,
+		Comment:      "gosh-ephemeral",
+		LifetimeSecs: 60,
+	}
+	if err := keyring.Add(addedKey); err != nil {
+		return "", nil, fmt.Errorf("failed to add key to agent: %w", err)
+	}
+
+	tempDir, err := os.MkdirTemp("", "gosh-*")
+	if err != nil {
+		return "", nil, fmt.Errorf("failed to make temporary directory: %w", err)
+	}
+	sockPath := filepath.Join(tempDir, "agent.sock")
+
+	l, err := net.Listen("unix", sockPath)
+	if err != nil {
+		return "", nil, fmt.Errorf("failed to listen on socket: %w", err)
+	}
+
+	go func() {
+		for {
+			conn, err := l.Accept()
+			if err != nil {
+				return
+			}
+			go agent.ServeAgent(keyring, conn)
+		}
+	}()
+
+	cleanup := func() {
+		l.Close()
+		os.RemoveAll(tempDir)
+	}
+	return sockPath, cleanup, nil
+}

db.go

@@ -34,6 +34,22 @@ func initDB(dbPath string) (*sql.DB, error) {
 	return db, nil
 }
 
+func findKey(db *sql.DB, user, host string) ([]byte, error) {
+	query := `
+	SELECT encrypted_pem FROM keys
+	WHERE (host_pattern = ? OR host_pattern = '*') AND (user_pattern = ? OR user_pattern = '*')
+	ORDER BY id DESC LIMIT 1;
+	`
+
+	var pemData []byte
+	err := db.QueryRow(query, host, user).Scan(&pemData)
+	if err != nil {
+		return nil, err
+	}
+
+	return pemData, nil
+}
+
 func addKey(db *sql.DB, userPattern, hostPattern, keyPath string) error {
 	pemData, err := os.ReadFile(keyPath)
 	if err != nil {

go.mod

@@ -2,7 +2,11 @@ module git.juancwu.dev/juancwu/gosh
 
 go 1.25.1
 
-require modernc.org/sqlite v1.43.0
+require (
+	golang.org/x/crypto v0.46.0
+	golang.org/x/term v0.39.0
+	modernc.org/sqlite v1.43.0
+)
 
 require (
 	github.com/dustin/go-humanize v1.0.1 // indirect
@@ -11,7 +15,7 @@ require (
 	github.com/ncruces/go-strftime v0.1.9 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
 	golang.org/x/exp v0.0.0-20250620022241-b7579e27df2b // indirect
-	golang.org/x/sys v0.36.0 // indirect
+	golang.org/x/sys v0.40.0 // indirect
 	modernc.org/libc v1.66.10 // indirect
 	modernc.org/mathutil v1.7.1 // indirect
 	modernc.org/memory v1.11.0 // indirect

go.sum

@@ -10,6 +10,8 @@ github.com/ncruces/go-strftime v0.1.9 h1:bY0MQC28UADQmHmaF5dgpLmImcShSi2kHU9XLdh
 github.com/ncruces/go-strftime v0.1.9/go.mod h1:Fwc5htZGVVkseilnfgOVb9mKy6w1naJmn9CehxcKcls=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
+golang.org/x/crypto v0.46.0 h1:cKRW/pmt1pKAfetfu+RCEvjvZkA9RimPbh7bhFjGVBU=
+golang.org/x/crypto v0.46.0/go.mod h1:Evb/oLKmMraqjZ2iQTwDwvCtJkczlDuTmdJXoZVzqU0=
 golang.org/x/exp v0.0.0-20250620022241-b7579e27df2b h1:M2rDM6z3Fhozi9O7NWsxAkg/yqS/lQJ6PmkyIV3YP+o=
 golang.org/x/exp v0.0.0-20250620022241-b7579e27df2b/go.mod h1:3//PLf8L/X+8b4vuAfHzxeRUl04Adcb341+IGKfnqS8=
 golang.org/x/mod v0.27.0 h1:kb+q2PyFnEADO2IEF935ehFUXlWiNjJWtRNgBLSfbxQ=
@@ -17,8 +19,10 @@ golang.org/x/mod v0.27.0/go.mod h1:rWI627Fq0DEoudcK+MBkNkCe0EetEaDSwJJkCcjpazc=
 golang.org/x/sync v0.16.0 h1:ycBJEhp9p4vXvUZNszeOq0kGTPghopOL8q0fq3vstxw=
 golang.org/x/sync v0.16.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.36.0 h1:KVRy2GtZBrk1cBYA7MKu5bEZFxQk4NIDV6RLVcC8o0k=
-golang.org/x/sys v0.36.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/sys v0.40.0 h1:DBZZqJ2Rkml6QMQsZywtnjnnGvHza6BTfYFWY9kjEWQ=
+golang.org/x/sys v0.40.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/term v0.39.0 h1:RclSuaJf32jOqZz74CkPA9qFuVTX7vhLlpfj/IGWlqY=
+golang.org/x/term v0.39.0/go.mod h1:yxzUCTP/U+FzoxfdKmLaA0RV1WgE0VY7hXBwKtY/4ww=
 golang.org/x/tools v0.36.0 h1:kWS0uv/zsvHEle1LbV5LE8QujrxB3wfQyxHfhOk0Qkg=
 golang.org/x/tools v0.36.0/go.mod h1:WBDiHKJK8YgLHlcQPYQzNCkUxUypCaa5ZegCVutKm+s=
 modernc.org/cc/v4 v4.26.5 h1:xM3bX7Mve6G8K8b+T11ReenJOT+BmVqQj0FY5T4+5Y4=

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)
+	}
 }

utils.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"strings"
+)
+
+func parseDestination(args []string) (user, host string) {
+	argsWithParams := map[string]bool{
+		"-b": true, "-c": true, "-D": true, "-E": true, "-e": true,
+		"-F": true, "-I": true, "-i": true, "-L": true, "-l": true,
+		"-m": true, "-O": true, "-o": true, "-p": true, "-R": true,
+		"-S": true, "-W": true, "-w": true,
+	}
+
+	skipNext := false
+	for _, arg := range args {
+		if skipNext {
+			skipNext = false
+			continue
+		}
+		if strings.HasPrefix(arg, "-") {
+			flag := arg
+			if len(arg) > 2 && !strings.Contains(arg, "=") {
+				flag = "-" + string(arg[len(arg)-1])
+			}
+
+			if argsWithParams[flag] {
+				skipNext = true
+			}
+			continue
+		}
+
+		parts := strings.SplitN(arg, "@", 2)
+		if len(parts) == 2 {
+			return parts[0], parts[1]
+		}
+		return "", parts[0] // No user specified, just host
+	}
+	return "", ""
+}