fix rootfs detection per bug #552052

ZFS and btrfs tools if not explictly configured (either way), default to
detecting the fstype of the rootfs.

The old rootfs detection method was NOT reliable in all cases; so
replace it with a different way. Future improvements should check for
rootfs AND the local existence of the required binaries (and bail out
early if the the rootrfs was detected but the binaries are not present).

Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>

2 files changed, 5 insertions, 3 deletions

diff --git a/gen_cmdline.sh b/gen_cmdline.sh
index 01adfdd..e9e7401 100755
--- a/gen_cmdline.sh
+++ b/gen_cmdline.sh
@@ -100,9 +100,9 @@ longusage() {
   echo "	--no-dmraid		Exclude DMRAID support"
   echo "	--e2fsprogs		Include e2fsprogs"
   echo "	--no-e2fsprogs		Exclude e2fsprogs"
-  echo "	--zfs			Include ZFS support"
+  echo "	--zfs			Include ZFS support (enabled by default if rootfs is zfs)"
   echo "	--no-zfs		Exclude ZFS support"
-  echo "	--btrfs			Include Btrfs support"
+  echo "	--btrfs			Include Btrfs support (enabled by default if rootfs is btrfs)"
   echo "	--no-btrfs		Exclude Btrfs support"
   echo "	--multipath		Include Multipath support"
   echo "	--no-multipath	Exclude Multipath support"
diff --git a/gen_funcs.sh b/gen_funcs.sh
index 37942ad..eb807ad 100755
--- a/gen_funcs.sh
+++ b/gen_funcs.sh
@@ -498,7 +498,9 @@ set_config_with_override() {
 rootfs_type_is() {
 	local fstype=$1
 
-	if $(df -t ${fstype} / 2>/dev/null 1>/dev/null)
+	# It is possible that the awk will return MULTIPLE lines, depending on your
+	# initramfs setup (one of the entries will be 'rootfs').
+	if awk '($2=="/"){print $3}' /proc/mounts | grep -sq --line-regexp "$fstype" ;
 	then
 		echo yes
 	else