[OE-core] [PATCH v2] udev-extraconf: Add systemd-mount to udev-extraconf/mount.sh

[Hongzhi.Song]

This patch fixs the problem that block devices unable to be formatted when
systemd and udev-extraconf recipes added to rootfs.

If we add systemd and udev-extraconf recipes to rootfs:
    VIRTUAL-RUNTIME_init_manager = "systemd"
    DISTRO_FEATURES_append = " systemd"
    DISTRO_FEATURES_BACKFILL_CONSIDERED += "sysvinit"
    KERNEL_FEATURES_append = " cfg/systemd.scc"
    IMAGE_INSTALL_append = " udev-extraconf"
    IMAGE_FSTYPES += "tar.bz2 ext4"
    IMAGE_INSTALL_append = " e2fsprogs-mke2fs"
then systemd-udevd.service will invoke udev rules to automount block devices
any probed under udevd's private namespace, this behavior results in host space
can't format those devices. And host space can't find where the device is used.

Such as:
    root at qemux86:~# mkfs.ext4 /dev/sda1
    mke2fs 1.43.8 (1-Jan-2018)
    /dev/sda1 contains a ext4 file system
    last mounted on Tue Apr  3 06:22:41 2018
    Proceed anyway? (y,N) y
    /dev/sda1 is apparently in use by the system; will not make a filesystem here!

Command 'systemd-mount' recommended by systemd maintainer instead of command
'mount' will fix the problem brought with private namespace. Systemd-mount
request the mount operation to be executed by PID 1, and hence host space can
access the block devices.

[YOCTO #12644]

Signed-off-by: Hongzhi.Song <hongzhi.song at windriver.com>
---
 meta/recipes-core/udev/udev-extraconf/mount.sh | 71 ++++++++++++++++++++++----
 1 file changed, 60 insertions(+), 11 deletions(-)

diff --git a/meta/recipes-core/udev/udev-extraconf/mount.sh b/meta/recipes-core/udev/udev-extraconf/mount.sh
index d760328a09..4ba9f1dd99 100644
--- a/meta/recipes-core/udev/udev-extraconf/mount.sh
+++ b/meta/recipes-core/udev/udev-extraconf/mount.sh
@@ -4,10 +4,28 @@
 #
 # Attempt to mount any added block devices and umount any removed devices
 
+BASE_INIT="`readlink "/sbin/init"`"
+INIT_SYSTEMD="/lib/systemd/systemd"
+
+if [ "x$BASE_INIT" = "x$INIT_SYSTEMD" ];then
+	# systemd as init uses systemd-mount to mount block devices
+    MOUNT="/usr/bin/systemd-mount"
+    UMOUNT="/usr/bin/systemd-umount"
+
+    if [ -x $MOUNT ] && [ -x $UMOUNT ];
+    then
+        logger "Using systemd-mount to finish mount"
+    else
+        logger "Linux init is using systemd, so please install systemd-mount to finish mount"
+        exit 1
+    fi
+else
+    MOUNT="/bin/mount"
+    UMOUNT="/bin/umount"
+fi
 
-MOUNT="/bin/mount"
 PMOUNT="/usr/bin/pmount"
-UMOUNT="/bin/umount"
+
 for line in `grep -h -v ^# /etc/udev/mount.blacklist /etc/udev/mount.blacklist.d/*`
 do
 	if [ ` expr match "$DEVNAME" "$line" ` -gt 0 ];
@@ -17,7 +35,35 @@ do
 	fi
 done
 
-automount() {	
+automount_systemd() {
+    name="`basename "$DEVNAME"`"
+
+    ! test -d "/run/media/$name" && mkdir -p "/run/media/$name"
+
+    MOUNT="$MOUNT -o silent"
+
+    # If filesystemtype is vfat, change the ownership group to 'disk', and
+    # grant it with  w/r/x permissions.
+    case $ID_FS_TYPE in
+    vfat|fat)
+        MOUNT="$MOUNT -o umask=007,gid=`awk -F':' '/^disk/{print $3}' /etc/group`"
+        ;;
+    # TODO
+    *)
+        ;;
+    esac
+
+    if ! $MOUNT --no-block -t auto $DEVNAME "/run/media/$name"
+    then
+        #logger "mount.sh/automount" "$MOUNT -t auto $DEVNAME \"/run/media/$name\" failed!"
+        rm_dir "/run/media/$name"
+    else
+        logger "mount.sh/automount" "Auto-mount of [/run/media/$name] successful"
+        touch "/tmp/.automount-$name"
+    fi
+}
+
+automount() {
 	name="`basename "$DEVNAME"`"
 
 	! test -d "/run/media/$name" && mkdir -p "/run/media/$name"
@@ -26,7 +72,7 @@ automount() {
 	then
 		MOUNT="$MOUNT -o silent"
 	fi
-	
+
 	# If filesystem type is vfat, change the ownership group to 'disk', and
 	# grant it with  w/r/x permissions.
 	case $ID_FS_TYPE in
@@ -46,7 +92,7 @@ automount() {
 		logger "mount.sh/automount" "Auto-mount of [/run/media/$name] successful"
 		touch "/tmp/.automount-$name"
 	fi
-}
+
 	
 rm_dir() {
 	# We do not want to rm -r populated directories
@@ -68,22 +114,25 @@ if [ "$ACTION" = "add" ] && [ -n "$DEVNAME" ] && [ -n "$ID_FS_TYPE" -o "$media_t
 	elif [ -x $MOUNT ]; then
     		$MOUNT $DEVNAME 2> /dev/null
 	fi
-	
+
 	# If the device isn't mounted at this point, it isn't
 	# configured in fstab (note the root filesystem can show up as
 	# /dev/root in /proc/mounts, so check the device number too)
-	if expr $MAJOR "*" 256 + $MINOR != `stat -c %d /`; then
-		grep -q "^$DEVNAME " /proc/mounts || automount
-	fi
+    if expr $MAJOR "*" 256 + $MINOR != `stat -c %d /`; then
+        if [ "`basename $MOUNT`" = "systemd-mount" ];then
+            grep -q "^$DEVNAME " /proc/mounts || automount_systemd
+        else
+            grep -q "^$DEVNAME " /proc/mounts || automount
+        fi
+    fi
 fi
 
-
 if [ "$ACTION" = "remove" ] || [ "$ACTION" = "change" ] && [ -x "$UMOUNT" ] && [ -n "$DEVNAME" ]; then
 	for mnt in `cat /proc/mounts | grep "$DEVNAME" | cut -f 2 -d " " `
 	do
 		$UMOUNT $mnt
 	done
-	
+
 	# Remove empty directories from auto-mounter
 	name="`basename "$DEVNAME"`"
 	test -e "/tmp/.automount-$name" && rm_dir "/run/media/$name"
-- 
2.13.3