Handle possible failures of xfs_info command

In case the xfs_info command fails for any reason, xfsinfoscanner
would crash. By no reason this should cause leapp to exit with a traceback.
An additional vetting if the directory is an actual mount point has been
added together with proper exception handling.
Unit tests also added.

OAMG-8147
BZ#2155661 - leapp xfs_info_scanner fails when fstab xfs entry not mounted

Author: fernflower

repos/system_upgrade/common/actors/xfsinfoscanner/libraries/xfsinfoscanner.py

@@ -1,4 +1,6 @@
-from leapp.libraries.stdlib import api, run, CalledProcessError
+import os
+
+from leapp.libraries.stdlib import api, CalledProcessError, run
 from leapp.models import StorageInfo, XFSPresence
 
 
@@ -21,18 +23,21 @@ def scan_xfs_mount(data):
 
 
 def is_xfs_without_ftype(mp):
-    try:
-        for l in run(['/usr/sbin/xfs_info', '{}'.format(mp)], split=True)['stdout']:
-            if 'ftype=0' in l:
-                return True
+    if not os.path.ismount(mp):
+        # Check if mp is actually a mountpoint
+        api.current_logger().warning('{} is not mounted'.format(mp))
         return False
-    # xfs_info can sometimes throw errors like the following if fed a CageFS mountpoint.
-    # xfs_info: /usr/share/cagefs-skeleton/var/www/cgi-bin\040(deleted) is not a mounted XFS filesystem
+    try:
+        xfs_info = run(['/usr/sbin/xfs_info', '{}'.format(mp)], split=True)
     except CalledProcessError as err:
-        if "cagefs" in mp:
-            api.current_logger().info("CageFS XFS mountpoint {} ignored in scanner".format(mp))
-            return False
-        raise err
+        api.current_logger().warning('Error during command execution: {}'.format(err))
+        return False
+
+    for l in xfs_info['stdout']:
+        if 'ftype=0' in l:
+            return True
+
+    return False
 
 
 def scan_xfs():

repos/system_upgrade/common/actors/xfsinfoscanner/tests/unit_test_xfsinfoscanner.py

@@ -1,7 +1,9 @@
+import os
+
 from leapp.libraries.actor import xfsinfoscanner
 from leapp.libraries.common.testutils import produce_mocked
-from leapp.libraries.stdlib import api
-from leapp.models import StorageInfo, FstabEntry, MountEntry, SystemdMountEntry, XFSPresence
+from leapp.libraries.stdlib import api, CalledProcessError
+from leapp.models import FstabEntry, MountEntry, StorageInfo, SystemdMountEntry, XFSPresence
 
 
 class run_mocked(object):
@@ -87,6 +89,7 @@ def test_scan_xfs_mount(monkeypatch):
 
 def test_is_xfs_without_ftype(monkeypatch):
     monkeypatch.setattr(xfsinfoscanner, "run", run_mocked())
+    monkeypatch.setattr(os.path, "ismount", lambda _: True)
 
     assert xfsinfoscanner.is_xfs_without_ftype("/var")
     assert ' '.join(xfsinfoscanner.run.args) == "/usr/sbin/xfs_info /var"
@@ -95,8 +98,22 @@ def test_is_xfs_without_ftype(monkeypatch):
     assert ' '.join(xfsinfoscanner.run.args) == "/usr/sbin/xfs_info /boot"
 
 
+def test_is_xfs_command_failed(monkeypatch):
+    def _run_mocked_exception(*args, **kwargs):
+        raise CalledProcessError(message="No such file or directory", command=["xfs_info", "/nosuchmountpoint"],
+                                 result=1)
+    # not a mountpoint
+    monkeypatch.setattr(os.path, "ismount", lambda _: False)
+    monkeypatch.setattr(xfsinfoscanner, "run", _run_mocked_exception)
+    assert not xfsinfoscanner.is_xfs_without_ftype("/nosuchmountpoint")
+    # a real mountpoint but something else caused command to fail
+    monkeypatch.setattr(os.path, "ismount", lambda _: True)
+    assert not xfsinfoscanner.is_xfs_without_ftype("/nosuchmountpoint")
+
+
 def test_scan_xfs(monkeypatch):
     monkeypatch.setattr(xfsinfoscanner, "run", run_mocked())
+    monkeypatch.setattr(os.path, "ismount", lambda _: True)
 
     def consume_no_xfs_message_mocked(*models):
         yield StorageInfo()