support udisks2 mount tool, fall back to system mount/unmount

3 files changed, 93 insertions, 26 deletions

diff --git a/README.md b/README.md
index 18cbad2..293ac0f 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,8 @@ A presentation in Chinese is at https://wehack.space/vimacs/liveusb-builder.odp.
 You need these packages on your GNU/Linux system to use liveusb-builder.
 
 - libarchive: for ISO image extraction
-- udevil: for mounting USB disk partitions
+- udisks2 (optional,recommended): for mounting USB disk partitions without being root
+- udevil (optional): for mounting USB disk partitions and ISO images without being root
 - wget: for downloading
 - syslinux (recommended): bootloader for legacy BIOS
 - GRUB: bootloader for legacy BIOS if there's no syslinux, and bootloader for UEFI
diff --git a/buildlive b/buildlive
index 120c14d..bc2c12e 100755
--- a/buildlive
+++ b/buildlive
@@ -20,15 +20,6 @@ CLEAN_USB=0
 
 . functions.sh
 
-msg() {
-	echo -e "$1" >&2
-}
-
-fatalerror() {
-	msg "\x1b[1;31m$1\x1b[0m"
-	exit 1
-}
-
 usage() {
 	>&2 cat << EOF
 $0 [--root <path>] [options] [--distro=<metadist> <isofile>] [distro] ...
@@ -52,7 +43,7 @@ try_mount() {
 	then
 		if ! findmnt "$1" > /dev/null
 		then
-			udevil mount "$1" > /dev/null
+			mount_block "$1" > /dev/null
 			mnt=$(findmnt -n -o TARGET "$1")
 		else
 			mnt=$(findmnt -n -o TARGET "$1")
@@ -63,6 +54,9 @@ try_mount() {
 	echo "$mnt"
 }
 
+detect_block_mount_tool 2>/dev/null
+detect_iso_mount_tool 2>/dev/null
+
 unset ISOPATH
 CFGFILE="$HOME/.liveusb-builder"
 test -f "$CFGFILE" && source "$CFGFILE" || true
@@ -263,9 +257,9 @@ fi
 
 if [ "$UMOUNT_BOOT" == 1 ]; then
 	msg 'Trying to umount the boot mountpoint, you may need to wait for sync() to complete.'
-	udevil umount "$BOOTPATH"
+	unmount_block "$BOOTPATH"
 fi
 if [ "$UMOUNT_ROOT" == 1 -a "$ROOTPATH" != "$BOOTPATH" ]; then
 	msg 'Trying to umount the root mountpoint, you may need to wait for sync() to complete.'
-	udevil umount "$ROOTPATH"
+	unmount_block "$ROOTPATH"
 fi
diff --git a/functions.sh b/functions.sh
index 8f9db5f..b967388 100644
--- a/functions.sh
+++ b/functions.sh
@@ -1,6 +1,26 @@
 # Copyright (C)  2016-2018 Iru Cai <mytbk920423@gmail.com>
 # SPDX-License-Identifier: GPL-3.0-or-later
 
+msg() {
+	echo -e "$1" >&2
+}
+
+fatalerror() {
+	msg "\x1b[1;31m$1\x1b[0m"
+	exit 1
+}
+
+as-root() {
+	echo as-root "$*"
+	if [ "$UID" == 0 ]; then
+		"$@"
+	elif type -p sudo > /dev/null; then
+		sudo "$@"
+	elif type -p su > /dev/null; then
+		su -c "$*"
+	fi
+}
+
 checksum_verify() {
 	local _hashtool _hashsum _cksum
 	if [ -n "$SHA512" ]; then
@@ -194,6 +214,69 @@ get_iso_label() {
 	file -b "$1" | cut -d\' -f2
 }
 
+# We try to a proper mount tool to mount block devices and iso files,
+# if we cannot find it, use the system mount tool.
+# Both udisks2 and udevil can mount block devices, but only udevil
+# can mount iso files.
+detect_block_mount_tool() {
+       if (udisksctl status | grep DEVICE > /dev/null); then
+	       BLOCKMOUNT=udisks2
+       elif (udevil | grep 'udevil version' > /dev/null); then
+	       BLOCKMOUNT=udevil
+       else
+	       BLOCKMOUNT=system
+       fi
+}
+
+detect_iso_mount_tool() {
+       if (udevil | grep 'udevil version' > /dev/null); then
+	       ISOMOUNT=udevil
+       else
+	       ISOMOUNT=system
+       fi
+}
+
+udevil_mount() {
+	udevil mount "$1"
+}
+
+udevil_unmount() {
+	udevil umount "$1"
+}
+
+udisks2_mount() {
+	udisksctl mount -b "$1"
+}
+
+udisks2_unmount() {
+	local mnt_source
+	mnt_source="$(findmnt -n -o SOURCE "$1")"
+	udisksctl unmount -b "${mnt_source}"
+}
+
+system_mount() {
+	local mountpoint
+	local uid
+	mountpoint="$(mktemp -d)"
+	uid="$(id -u)"
+	# first try uid= option of mount(1)
+	if ! as-root mount -o "uid=$uid" "$1" "$mountpoint" 2> /dev/null; then
+		as-root mount "$1" "$mountpoint"
+	fi
+}
+
+system_unmount() {
+	as-root umount "$1"
+}
+
+mount_block() {
+	${BLOCKMOUNT}_mount "$1"
+}
+
+unmount_block() {
+	${BLOCKMOUNT}_unmount "$1"
+}
+
 mount_iso() {
 	LOOPDEV=$(/sbin/losetup -n -O NAME -j "${ISO_FILEPATH}")
 	if [[ -n "$LOOPDEV" ]]
@@ -202,7 +285,7 @@ mount_iso() {
 		umount_iso
 	fi
 
-	udevil mount "${ISO_FILEPATH}"
+	${ISOMOUNT}_mount "${ISO_FILEPATH}"
 	LOOPDEV=$(/sbin/losetup -n -O NAME -j "${ISO_FILEPATH}")
 	if [[ -n "$LOOPDEV" ]]
 	then
@@ -211,7 +294,7 @@ mount_iso() {
 }
 
 umount_iso() {
-	udevil umount "$ISOMNT"
+	${ISOMOUNT}_unmount "$ISOMNT"
 }
 
 # iso_extract: extract files from iso image to destination path
@@ -247,17 +330,6 @@ getdiskbypart() {
 	done
 }
 
-as-root() {
-	echo as-root "$*"
-	if [ "$UID" == 0 ]; then
-		"$@"
-	elif type -p sudo > /dev/null; then
-		sudo "$@"
-	elif type -p su > /dev/null; then
-		su -c "$*"
-	fi
-}
-
 syslinux_header() {
 	cat << EOF
 UI menu.c32