fix: Add a verity_cleanup function to test helpers.bash

The atomfs bad verity test case ends up leaving verity and loop
devices which then break other test cases.  Tearing a bad verity
device down requires more inspection of the system to determine the
correct verity hash device name and the loop device in use.  Add
the verity_cleanup to the teardown() method in atomfs and squashfs
tests.

Fixes: #541

Signed-off-by: Ryan Harper <rharper@woxford.com>

test/atomfs.bats

@@ -6,6 +6,7 @@ function setup() {
 
 function teardown() {
     cleanup
+    verity_cleanup
 }
 
 function basic_test() {

test/helpers.bash

@@ -76,6 +76,42 @@ function cleanup() {
     rm -rf "$TEST_TMPDIR" || true
 }
 
+function verity_cleanup() {
+    # search for loopdevices which have backing files with the current BATS_TEST_NAME value
+    # if we find them, we can use them to tear down the verity device, and cleanup the loopdev
+    # normally, on verity close, the loop dev is removed as well, but on the bad test, it does
+    # not, so we have to clean that up here.
+
+    usedloop=$(losetup -a | grep "$BATS_TEST_NAME")
+    if [ -n "$usedloop" ]; then
+        echo "found a used loop device $usedloop"
+
+        loopdev=$(echo "$usedloop" | cut -d: -f1)
+        loopname=${loopdev##*/}
+        echo "loopdev=$loopdev loopname=$loopname"
+
+        badloop_hash=$(basename "$(<"/sys/class/block/$loopname/loop/backing_file")")
+        echo "badloop_hash=$badloop_hash"
+
+        bad_devname="/dev/mapper/${badloop_hash}-verity"
+        echo "Checking if bad verity device $bad_devname exists..."
+
+        while [ -b "$bad_devname" ]; do
+            echo "closing verity device $bad_devname"
+            veritysetup close "$bad_devname" || true
+            udevadm settle
+            sleep 1
+        done
+
+        while [ -e "/sys/class/block/$loopname/loop" ]; do
+            echo "closing loop device $loopdev"
+            losetup -d "$loopdev" || true
+            udevadm settle
+            sleep 1
+        done
+    fi
+}
+
 function run_as {
     if [ "$PRIVILEGE_LEVEL" = "priv" ]; then
         "$@"

test/squashfs.bats

@@ -11,6 +11,7 @@ function teardown() {
     umount layer1 || true
     rm -rf layer0 layer1 || true
     cleanup
+    verity_cleanup
 }
 
 @test "squashfs + derivative build only layers" {