From 2a9786f08981626b9c079677b6a2daf91a08d2f1 Mon Sep 17 00:00:00 2001
From: Joey Riches <josephriches@gmail.com>
Date: Sun, 15 Sep 2024 13:37:13 +0100
Subject: [PATCH] builder/chroot: Use ChrootShell() instead of
 ChrootExecStdin()

With ChrootShell() we can drop usage of the chroot binary, as well as
choose the initial workdir to spawn in to.

As the files are now build as root, they are owned by root so chroot
as root but start at the buildUser home directory.
---
 builder/chroot.go | 10 ++--------
 builder/util.go   | 27 +++++++++++++++------------
 2 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/builder/chroot.go b/builder/chroot.go
index 017ec22..cf385c8 100644
--- a/builder/chroot.go
+++ b/builder/chroot.go
@@ -66,14 +66,8 @@ func (p *Package) Chroot(notif PidNotifier, pman *EopkgManager, overlay *Overlay
 	// Allow bash to work
 	commands.SetStdin(os.Stdin)
 
-	// Legacy package format requires root, stay as root.
-	user := BuildUser
-	if p.Type == PackageTypeXML {
-		user = "root"
-	}
-
-	loginCommand := fmt.Sprintf("/bin/su - %s -s %s", user, BuildUserShell)
-	err := ChrootExecStdin(notif, overlay.MountPoint, loginCommand)
+	loginCommand := fmt.Sprintf("/bin/su - root -s %s", BuildUserShell)
+	err := ChrootShell(notif, overlay.MountPoint, loginCommand, BuildUserHome)
 
 	commands.SetStdin(nil)
 	notif.SetActivePID(0)
diff --git a/builder/util.go b/builder/util.go
index 4f6a627..98ae682 100644
--- a/builder/util.go
+++ b/builder/util.go
@@ -231,7 +231,6 @@ func ChrootExecStdin(notif PidNotifier, dir, command string) error {
 }
 
 func ChrootShell(notif PidNotifier, dir, command, workdir string) error {
-
 	// Hold an fd for the og root
 	fd, err := os.Open("/")
 	if err != nil {
@@ -239,22 +238,22 @@ func ChrootShell(notif PidNotifier, dir, command, workdir string) error {
 	}
 
 	// Remember our working directory
-	wd, err := os.Getwd()
-	if err != nil {
-		return err
+	wd, err2 := os.Getwd()
+	if err2 != nil {
+		return err2
 	}
 
 	// Ensure chroot directory is available
-	if err := os.Chdir(dir); err != nil {
+	if err = os.Chdir(dir); err != nil {
 		return err
 	}
 
-	if err := syscall.Chroot(dir); err != nil {
+	if err = syscall.Chroot(dir); err != nil {
 		fd.Close()
 		return err
 	}
 
-	if err := os.Chdir("/"); err != nil {
+	if err = os.Chdir("/"); err != nil {
 		return err
 	}
 
@@ -267,28 +266,32 @@ func ChrootShell(notif PidNotifier, dir, command, workdir string) error {
 	c.Env = ChrootEnvironment
 	c.Dir = workdir
 
-	if err := c.Start(); err != nil {
+	if err = c.Start(); err != nil {
 		goto CLEANUP
 	}
 
 	notif.SetActivePID(c.Process.Pid)
 
-	if err := c.Wait(); err != nil {
+	if err = c.Wait(); err != nil {
 		goto CLEANUP
 	}
 
 CLEANUP:
 	// Return to our original root and working directory
 	defer fd.Close()
-	if err := fd.Chdir(); err != nil {
+
+	if err = fd.Chdir(); err != nil {
 		return err
 	}
-	if err := syscall.Chroot("."); err != nil {
+
+	if err = syscall.Chroot("."); err != nil {
 		return err
 	}
-	if err := os.Chdir(wd); err != nil {
+
+	if err = os.Chdir(wd); err != nil {
 		return err
 	}
+
 	return err
 }