From b9d44966acf7156c2666cbaaf03a2e05ac9f13fd Mon Sep 17 00:00:00 2001
From: Zac Bergquist <zac.bergquist@goteleport.com>
Date: Tue, 9 May 2023 13:29:34 -0600
Subject: [PATCH 1/2] User os.UserHomeDir where possible

In #24156 we removed a lot of unnecessary calls to user.Current,
which can take a long time in Active Directory environments.

This commit removes a few other uses of user.Current where we were
doing a full user lookup only to find the user's home directory,
which is usually more readily available via the environment.
---
 api/profile/profile.go                | 10 +++++++++-
 lib/client/db/mysql/optionfile.go     | 14 ++++++++++----
 lib/client/db/postgres/servicefile.go | 14 ++++++++++----
 3 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/api/profile/profile.go b/api/profile/profile.go
index a45a3cb3d3f0e..9b0dc273fe04a 100644
--- a/api/profile/profile.go
+++ b/api/profile/profile.go
@@ -313,7 +313,15 @@ func FullProfilePath(dir string) string {
 
 // defaultProfilePath retrieves the default path of the TSH profile.
 func defaultProfilePath() string {
-	home := os.TempDir()
+	// start with UserHomeDir, which is the fastest option as it
+	// relies only on environment variables and does not perform
+	// a user lookup (which can be very slow on large AD environments)
+	home, err := os.UserHomeDir()
+	if err == nil && home != "" {
+		return home
+	}
+
+	home = os.TempDir()
 	if u, err := utils.CurrentUser(); err == nil && u.HomeDir != "" {
 		home = u.HomeDir
 	}
diff --git a/lib/client/db/mysql/optionfile.go b/lib/client/db/mysql/optionfile.go
index 27557a72bc991..7bcee08192080 100644
--- a/lib/client/db/mysql/optionfile.go
+++ b/lib/client/db/mysql/optionfile.go
@@ -17,6 +17,7 @@ limitations under the License.
 package mysql
 
 import (
+	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -44,11 +45,16 @@ type OptionFile struct {
 
 func DefaultConfigPath() (string, error) {
 	// Default location is .my.cnf file in the user's home directory.
-	usr, err := utils.CurrentUser()
-	if err != nil {
-		return "", trace.ConvertSystemError(err)
+	home, err := os.UserHomeDir()
+	if err != nil || home == "" {
+		usr, err := utils.CurrentUser()
+		if err != nil {
+			return "", trace.ConvertSystemError(err)
+		}
+		home = usr.HomeDir
 	}
-	return filepath.Join(usr.HomeDir, mysqlOptionFile), nil
+
+	return filepath.Join(home, mysqlOptionFile), nil
 }
 
 // Load loads MySQL option file from the default location.
diff --git a/lib/client/db/postgres/servicefile.go b/lib/client/db/postgres/servicefile.go
index e23fb07b27877..6361c7d91f25c 100644
--- a/lib/client/db/postgres/servicefile.go
+++ b/lib/client/db/postgres/servicefile.go
@@ -17,6 +17,7 @@ limitations under the License.
 package postgres
 
 import (
+	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -46,11 +47,16 @@ type ServiceFile struct {
 func Load() (*ServiceFile, error) {
 	// Default location is .pg_service.conf file in the user's home directory.
 	// TODO(r0mant): Check PGSERVICEFILE and PGSYSCONFDIR env vars as well.
-	user, err := utils.CurrentUser()
-	if err != nil {
-		return nil, trace.ConvertSystemError(err)
+	home, err := os.UserHomeDir()
+	if err != nil || home == "" {
+		user, err := utils.CurrentUser()
+		if err != nil {
+			return nil, trace.ConvertSystemError(err)
+		}
+		home = user.HomeDir
 	}
-	return LoadFromPath(filepath.Join(user.HomeDir, pgServiceFile))
+
+	return LoadFromPath(filepath.Join(home, pgServiceFile))
 }
 
 // LoadFromPath loads Posrtgres connection service file from the specified path.

From eb83c4f079463a4eca8d112d4ca6c0be86e7e1a9 Mon Sep 17 00:00:00 2001
From: Zac Bergquist <zac.bergquist@goteleport.com>
Date: Wed, 10 May 2023 11:15:09 -0600
Subject: [PATCH 2/2] Fix tsh profile dir

This fixes a bug introduced in #25950
---
 api/profile/profile.go      |  2 +-
 api/profile/profile_test.go | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/api/profile/profile.go b/api/profile/profile.go
index 9b0dc273fe04a..d9c5987480cff 100644
--- a/api/profile/profile.go
+++ b/api/profile/profile.go
@@ -318,7 +318,7 @@ func defaultProfilePath() string {
 	// a user lookup (which can be very slow on large AD environments)
 	home, err := os.UserHomeDir()
 	if err == nil && home != "" {
-		return home
+		return filepath.Join(home, profileDir)
 	}
 
 	home = os.TempDir()
diff --git a/api/profile/profile_test.go b/api/profile/profile_test.go
index 6d22e436ae655..eab120e15093c 100644
--- a/api/profile/profile_test.go
+++ b/api/profile/profile_test.go
@@ -20,6 +20,7 @@ package profile_test
 import (
 	"os"
 	"path/filepath"
+	"runtime"
 	"testing"
 
 	"github.com/gravitational/trace"
@@ -102,3 +103,16 @@ func TestAppPath(t *testing.T) {
 	expected := filepath.Join(dir, "keys", "proxy", "testuser-app", "example.com", "banana-x509.pem")
 	require.Equal(t, expected, p.AppCertPath("banana"))
 }
+
+func TestProfilePath(t *testing.T) {
+	switch runtime.GOOS {
+	case "darwin", "linux":
+	default:
+		t.Skip("this test only runs on Unix")
+	}
+	dir := t.TempDir()
+	t.Setenv("HOME", dir)
+
+	require.Equal(t, "/foo/bar", profile.FullProfilePath("/foo/bar"))
+	require.Equal(t, filepath.Join(dir, ".tsh"), profile.FullProfilePath(""))
+}