refactor(ssh): improve find extended agent (#31)

1. add `Library/Group Containers/2BUA8C4S2C.com.1password/t/agent.sock`
path
2. support macos built-in agent fallback

Signed-off-by: Black-Hole1 <[email protected]>

Author: BlackHole1

pkg/sshagentsock/sshagentsock.go

@@ -9,6 +9,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"strconv"
+	"strings"
 
 	"github.com/oomol-lab/ovm-ssh-agent/pkg/identity"
 	"github.com/oomol-lab/ovm-ssh-agent/pkg/sshagent"
@@ -17,37 +18,46 @@ import (
 
 var knownAgentPaths = []string{
 	".1password/agent.sock",
+	"Library/Group Containers/2BUA8C4S2C.com.1password/t/agent.sock",
 }
 
+// FindExtendedAgent finds the extended agent path.
+// The find will be done in the following order:
+//
+// 1. Check if the environment variable SSH_AUTH_SOCK exists (if it is the built-in agent in macOS, it will be used as an alternative).
+// 2. Check if any known third-party agent exists at the specified path.
+// 3. Get the ssh auth sock of the current system using launchctl.
+// 4. If all the above steps fail, use the alternative. Otherwise, return empty
 func FindExtendedAgent() (socketPath string, ok bool) {
 	if p, ok := os.LookupEnv("SSH_AUTH_SOCK"); ok {
-		return p, true
+		if strings.Contains(p, "com.apple.launchd.") {
+			socketPath = p
+		} else {
+			return p, true
+		}
 	}
 
-	home, err := os.UserHomeDir()
-	if err != nil {
+	if home, err := os.UserHomeDir(); err != nil {
 		goto LAUNCHD
-	}
-
-	for _, p := range knownAgentPaths {
-		p = filepath.Join(home, p)
-		if _, err := os.Stat(p); err == nil {
-			return p, true
+	} else {
+		for _, p := range knownAgentPaths {
+			p = filepath.Join(home, p)
+			if _, err := os.Stat(p); err == nil {
+				return p, true
+			}
 		}
 	}
 
 LAUNCHD:
 	output, err := exec.Command("/bin/launchctl", "asuser", strconv.Itoa(os.Getuid()), "launchctl", "getenv", "SSH_AUTH_SOCK").CombinedOutput()
-	if err != nil {
-		return "", false
-	}
-
-	out := string(bytes.TrimSpace(output))
-	if _, err := os.Stat(out); err == nil {
-		return out, true
+	if err == nil {
+		out := string(bytes.TrimSpace(output))
+		if _, err := os.Stat(out); err == nil {
+			return out, true
+		}
 	}
 
-	return "", false
+	return socketPath, false
 }
 
 func Start(sshAuthSocketPath string, log *logger.Context) (*sshagent.SSHAgent, error) {