Bug#735169: os-prober cannot work with the latest upstream blkid (util-linux-2.24)

[Andreas Henriksson <andreas@fatal.se>]

Control: tags -1 + patch

Hello!

I'm working on an updated util-linux package (v2.24.2) and was pointed
to this os-prober bug report.

In my limited testing I haven't been able to reproduce any problems
here with os-prober and util-linux 2.24.2.

I can confirm though that the behaviour of running blkid against
an extended dos partition has changed. In the new version information
is correctly reported for those instead of just erroring out.

The old blkid version (2.20.1) returns error code 2 when running
against an extended dos partition.

$ sudo blkid -V
blkid from util-linux 2.24.2  (libblkid 2.24.0, 24-Apr-2014)

$ sudo blkid -o export /dev/sda2
DEVNAME=/dev/sda2
PTUUID=dd6e951b
PTTYPE=dos
PARTUUID=000ae69f-02

$ sudo blkid /dev/sda2
/dev/sda2: PTUUID="dd6e951b" PTTYPE="dos" PARTUUID="000ae69f-02"


I'm attaching a patch that should hopefully help. It tries to make the
executed codepath similar to what it was by adding an extra check on the
case where value of TYPE is "" and then exits 0 if it looks like an
extended dos partition.

Any feedback would be greatly appreciated.

Regards,
Andreas Henriksson

diff --git a/common.sh b/common.sh
index 30e245e..8734b62 100644
--- a/common.sh
+++ b/common.sh
@@ -116,6 +116,29 @@ fs_type () {
 	fi
 }
 
+is_dos_extended_partition() {
+	if type blkid >/dev/null 2>&1; then
+		local output
+
+		output="$(blkid -o export $1)"
+
+		# old blkid (util-linux << 2.24) errors out on extended p.
+		if [ "$?" = "2" ]; then
+			return 0
+		fi
+
+		# dos partition type and no filesystem type?...
+		if echo $output | grep -q ' PTTYPE=dos ' &&
+				! echo $output | grep -q ' TYPE='; then
+			return 0
+		else
+			return 1
+		fi
+	fi
+
+	return 1
+}
+
 parse_proc_mounts () {
 	while read -r line; do
 		set -f
diff --git a/linux-boot-probes/common/50mounted-tests b/linux-boot-probes/common/50mounted-tests
index 41e26e6..91b6dd9 100755
--- a/linux-boot-probes/common/50mounted-tests
+++ b/linux-boot-probes/common/50mounted-tests
@@ -20,6 +20,10 @@ elif [ "$types" = ntfs ]; then
 		types='ntfs-3g ntfs'
 	fi
 elif [ -z "$types" ]; then
+	if is_dos_extended_partition "$partition"; then
+		debug "$1 looks like an extended dos partition; skipping"
+		exit 0
+	fi
 	if type cryptsetup >/dev/null 2>&1 && \
 	   cryptsetup luksDump "$partition" >/dev/null 2>&1; then
 		debug "$1 is a LUKS partition; skipping"