[arch-releng] [PATCH] [archiso] Refactor: Use losetup from util-linux

[Gerardo Exequiel Pozzi]

New losetup from util-linux 2.21 uses new /dev/loop-control from Linux 3.1.

Needs mkinitcpio-0.8.2+ (provides modules.devname, or workaround with earlymodules=loop)

Get advantages from it! Removing custom shell code.

(tested and working, will be merged when next util-linux/mkinitcpio hits [core])

Signed-off-by: Gerardo Exequiel Pozzi <vmlinuz386 at yahoo.com.ar>
---
 archiso/hooks/archiso          |   37 +++----------------------------------
 archiso/hooks/archiso_loop_mnt |   10 ++++------
 archiso/install/archiso        |    1 +
 3 files changed, 8 insertions(+), 40 deletions(-)

diff --git a/archiso/hooks/archiso b/archiso/hooks/archiso
index 2635a4c..3518d16 100644
--- a/archiso/hooks/archiso
+++ b/archiso/hooks/archiso
@@ -1,27 +1,3 @@
-# Initialize loopback device logic (we using on-demand mode)
-# args: none
-_init_loop_dev() {
-    loop_dev_count=99
-    loop_dev_range=$(cat /sys/block/loop0/range)
-    loop_dev_minor=$((loop_dev_count*loop_dev_range))
-}
-
-# Call this function before _make_loop_dev() each time.
-# args: none
-_next_loop_dev() {
-    loop_dev_count=$((loop_dev_count+1))
-    loop_dev_minor=$((loop_dev_count*loop_dev_range))
-}
-
-# Setup a loopback device for image passed as argument and echo the path to loopback device used.
-# args: /path/to/image_file
-_make_loop_dev() {
-    local img="${1}"
-    mknod /dev/loop${loop_dev_count} b 7 ${loop_dev_minor} &> /dev/null
-    losetup /dev/loop${loop_dev_count} "${img}" &> /dev/null
-    echo /dev/loop${loop_dev_count}
-}
-
 # args: source, newroot, mountpoint
 _mnt_fs() {
     local img="${1}"
@@ -34,8 +10,7 @@ _mnt_fs() {
 
     mkdir -p "${newroot}${mnt}"
 
-    _next_loop_dev
-    ro_dev=$(_make_loop_dev "${img}")
+    ro_dev=$(losetup --find --show "${img}")
     ro_dev_size=$(blockdev --getsz ${ro_dev})
 
     if [[ "${cow_persistent}" == "P" ]]; then
@@ -54,8 +29,7 @@ _mnt_fs() {
         dd of="/run/archiso/cowspace/${cow_directory}/${img_name}.cow" count=0 seek=${ro_dev_size} &> /dev/null
     fi
 
-    _next_loop_dev
-    rw_dev=$(_make_loop_dev "/run/archiso/cowspace/${cow_directory}/${img_name}.cow")
+    rw_dev=$(losetup --find --show "/run/archiso/cowspace/${cow_directory}/${img_name}.cow")
 
     echo "0 ${ro_dev_size} snapshot ${ro_dev} ${rw_dev} ${cow_persistent} 8" | dmsetup create ${dm_snap_name}
 
@@ -85,9 +59,8 @@ _mnt_sfs() {
         img="/run/archiso/copytoram/${img_fullname}"
         msg "done."
     fi
-    _next_loop_dev
     msg ":: Mounting '${img}' (SquashFS) to '${mnt}'"
-    if ! mount -r $(_make_loop_dev "${img}") "${mnt}" &> /dev/null ; then
+    if ! mount -r "${img}" "${mnt}" &> /dev/null ; then
         echo "ERROR: while mounting '${img}' to '${mnt}'"
         launch_interactive_shell
     fi
@@ -130,8 +103,6 @@ _verify_checksum() {
 }
 
 run_hook() {
-    modprobe loop
-
     [[ -z "${arch}" ]] && arch="$(uname -m)"
     [[ -z "${cowspace_size}" ]] && cowspace_size="75%"
     [[ -z "${copytoram_size}" ]] && copytoram_size="75%"
@@ -166,8 +137,6 @@ run_hook() {
 archiso_mount_handler() {
     local newroot="${1}"
 
-    _init_loop_dev
-
     mountpoint -q "/run/archiso/bootmnt" || _mnt_dev "${archisodevice}" "/run/archiso/bootmnt" "-r"
 
     if [[ ! -f "${aitab}" ]]; then
diff --git a/archiso/hooks/archiso_loop_mnt b/archiso/hooks/archiso_loop_mnt
index e52dc69..664f3a5 100644
--- a/archiso/hooks/archiso_loop_mnt
+++ b/archiso/hooks/archiso_loop_mnt
@@ -10,15 +10,13 @@ run_hook () {
 archiso_loop_mount_handler () {
     newroot="${1}"
 
+    local _dev_loop
+
     msg ":: Setup a loop device from ${img_loop} located at device ${img_dev}"
     _mnt_dev "${img_dev}" "/run/archiso/img_dev" "-r"
 
-    _dev_loop=$(losetup -f)
-    if ! losetup "${_dev_loop}" "/run/archiso/img_dev/${img_loop}"; then
-        echo "ERROR: Setting loopback device '${_dev_loop}'"
-        echo "   for file '/run/archiso/img_dev/${img_loop}'"
-        echo "   Falling back to interactive prompt"
-        echo "   You can try to fix the problem manually, log out when you are finished"
+    if ! _dev_loop=$(losetup --find --show "/run/archiso/img_dev/${img_loop}"); then
+        echo "ERROR: Setting loopback device for file '/run/archiso/img_dev/${img_loop}'"
         launch_interactive_shell
     fi
 
diff --git a/archiso/install/archiso b/archiso/install/archiso
index 3b4e223..db0fc3a 100644
--- a/archiso/install/archiso
+++ b/archiso/install/archiso
@@ -8,6 +8,7 @@ build ()
     add_binary /lib/udev/cdrom_id
     add_binary /sbin/blockdev
     add_binary /sbin/dmsetup
+    add_binary /sbin/losetup
     add_binary /bin/mountpoint
 
     add_file /lib/udev/rules.d/60-cdrom_id.rules
-- 
1.7.8.1