From 9738db36645f2e8918954fbf573f5c71e294fc63 Mon Sep 17 00:00:00 2001
From: Ryan Finnie <ryan@finnie.org>
Date: Fri, 28 Oct 2022 14:44:51 -0700
Subject: [PATCH] Allow for mountless operation in non-privileged Docker
 containers

Docker does not allow for mounts within a non-privileged container.
debootstrap already has support for detecting and working around
this (as of 1.0.107), and, surprisingly, I have yet to find an
additional package whose pre-install/post-install hooks fail when
/proc and /sys are not present (though many notice and complain).

This commit changes:
- Warn upon /proc and /sys mount failures, but continue on
- Change hooks config within the chroot from a bind mound to a
  tree copy
---
 scripts/build/chroot_hooks | 17 +++++------------
 scripts/build/chroot_proc  |  5 ++++-
 scripts/build/chroot_sysfs |  5 ++++-
 3 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/scripts/build/chroot_hooks b/scripts/build/chroot_hooks
index df0a427dc..9a8d7cdd1 100755
--- a/scripts/build/chroot_hooks
+++ b/scripts/build/chroot_hooks
@@ -32,14 +32,9 @@ Check_stagefile
 # Acquire lock file
 Acquire_lockfile
 
-# Make build config available to chroot hooks. First, make the bind
-# mount and then make it read-only. This can't happen in one mount
-# command, then the resulting mount will be rw (see mount(8)). Making it
-# ro prevents modifications and prevents accidentally removing the
-# contents of the config directory when removing the chroot.
-mkdir -p chroot/live-build/config
-mount -o bind config chroot/live-build/config
-mount -o remount,ro,bind config chroot/live-build/config
+# Make build config available to chroot hooks.
+mkdir -p chroot/live-build
+cp --recursive --preserve=mode,timestamps --dereference config chroot/live-build/config
 
 ## Processing hooks
 if ls config/hooks/normal/*.chroot > /dev/null 2>&1 && (
@@ -92,10 +87,8 @@ then
 	Save_package_cache chroot
 fi
 
-# Remove bind mount of build config inside chroot.
-umount chroot/live-build/config
-rmdir chroot/live-build/config
-rmdir chroot/live-build
+# Remove build config inside chroot.
+rm -rf chroot/live-build
 
 # Creating stage file
 Create_stagefile
diff --git a/scripts/build/chroot_proc b/scripts/build/chroot_proc
index fcc866932..d651dacf6 100755
--- a/scripts/build/chroot_proc
+++ b/scripts/build/chroot_proc
@@ -41,7 +41,10 @@ case "${_ACTION}" in
 		mkdir -p chroot/proc
 
 		# Mounting /proc
-		mount -t proc -o x-gvfs-hide proc-live chroot/proc
+		if ! mount -t proc -o x-gvfs-hide proc-live chroot/proc
+		then
+			Echo_warning "Cannot mount /proc (running in container?)"
+		fi
 
 		# Creating stage file
 		Create_stagefile
diff --git a/scripts/build/chroot_sysfs b/scripts/build/chroot_sysfs
index e4601abe1..d64003659 100755
--- a/scripts/build/chroot_sysfs
+++ b/scripts/build/chroot_sysfs
@@ -41,7 +41,10 @@ case "${_ACTION}" in
 		mkdir -p chroot/sys
 
 		# Mounting /sys
-		mount -t sysfs -o x-gvfs-hide sysfs-live chroot/sys
+		if ! mount -t sysfs -o x-gvfs-hide sysfs-live chroot/sys
+		then
+			Echo_warning "Cannot mount /sys (running in container?)"
+		fi
 
 		# Creating stage file
 		Create_stagefile