From e36cc530927c4294c1510d7cdf89f0b9739e6cde Mon Sep 17 00:00:00 2001
From: =?utf8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Wed, 28 Feb 2024 11:51:01 +0100
Subject: [PATCH] base-files: sysupgrade: use tar helper to include
 installed_packages.txt
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit

Replace mount + overlay with manually built tar archive that gets
prepended to the actual config files backup. This allows more
flexibility with including extra backup files. They can be included at
any paths and don't require writing to flash or mounting an overlay
which has its own limitations (mount points).

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Jo-Philipp Wich <jo@mein.io>
---
 package/base-files/files/sbin/sysupgrade | 44 +++++++++---------------
 1 file changed, 16 insertions(+), 28 deletions(-)

diff --git a/package/base-files/files/sbin/sysupgrade b/package/base-files/files/sbin/sysupgrade
index 6b3fb0666f..a11e17615c 100755
--- a/package/base-files/files/sbin/sysupgrade
+++ b/package/base-files/files/sbin/sysupgrade
@@ -237,8 +237,6 @@ include /lib/upgrade
 create_backup_archive() {
 	local conf_tar="$1"
 
-	local umount_etcbackup_dir=0
-
 	[ "$(rootfs_type)" = "tmpfs" ] && {
 		echo "Cannot save config while running from ramdisk." >&2
 		ask_bool 0 "Abort" && exit
@@ -248,41 +246,31 @@ create_backup_archive() {
 	run_hooks "$CONFFILES" $sysupgrade_init_conffiles
 	ask_bool 0 "Edit config file list" && vi "$CONFFILES"
 
-	if [ "$SAVE_INSTALLED_PKGS" -eq 1 ]; then
-		echo "${INSTALLED_PACKAGES}" >> "$CONFFILES"
-		mkdir -p "$ETCBACKUP_DIR"
-		# Avoid touching filesystem on each backup
-		RAMFS="$(mktemp -d -t sysupgrade.XXXXXX)"
-		mkdir -p "$RAMFS/upper" "$RAMFS/work"
-		mount -t overlay overlay -o lowerdir=$ETCBACKUP_DIR,upperdir=$RAMFS/upper,workdir=$RAMFS/work $ETCBACKUP_DIR &&
-			umount_etcbackup_dir=1 || {
-				echo "Cannot mount '$ETCBACKUP_DIR' as tmpfs to avoid touching disk while saving the list of installed packages." >&2
-				ask_bool 0 "Abort" && exit
-			}
-
-		# Format: pkg-name<TAB>{rom,overlay,unknown}
-		# rom is used for pkgs in /rom, even if updated later
-		find /usr/lib/opkg/info -name "*.control" \( \
-			\( -exec test -f /rom/{} \; -exec echo {} rom \; \) -o \
-			\( -exec test -f /overlay/upper/{} \; -exec echo {} overlay \; \) -o \
-			\( -exec echo {} unknown \; \) \
-			\) | sed -e 's,.*/,,;s/\.control /\t/' > ${INSTALLED_PACKAGES}
-	fi
-
 	v "Saving config files..."
 	[ "$VERBOSE" -gt 1 ] && TAR_V="v" || TAR_V=""
 	sed -i -e 's,^/,,' "$CONFFILES"
-	tar c${TAR_V}zf "$conf_tar" -C / -T "$CONFFILES"
+	{
+		# Part of archive with installed packages info
+		if [ "$SAVE_INSTALLED_PKGS" -eq 1 ]; then
+			# Format: pkg-name<TAB>{rom,overlay,unknown}
+			# rom is used for pkgs in /rom, even if updated later
+			tar_print_member "$INSTALLED_PACKAGES" "$(find /usr/lib/opkg/info -name "*.control" \( \
+				\( -exec test -f /rom/{} \; -exec echo {} rom \; \) -o \
+				\( -exec test -f /overlay/upper/{} \; -exec echo {} overlay \; \) -o \
+				\( -exec echo {} unknown \; \) \
+				\) | sed -e 's,.*/,,;s/\.control /\t/')"
+		fi
+
+		# Rest of archive with config files and ending padding
+		tar c${TAR_V} -C / -T "$CONFFILES"
+	} | gzip > "$conf_tar"
+
 	local err=$?
 	if [ "$err" -ne 0 ]; then
 		echo "Failed to create the configuration backup."
 		rm -f "$conf_tar"
 	fi
 
-	[ "$umount_etcbackup_dir" -eq 1 ] && {
-		umount "$ETCBACKUP_DIR"
-		rm -rf "$RAMFS"
-	}
 	rm -f "$CONFFILES"
 
 	return "$err"
-- 
2.30.2