ScanPamUserDB: implement scan to detect DB location

pam_userdb module changed its backend database technology from lidb to
gdbm for RHEL10. This requires a set of leapp actors to perform the
database migration automatically when upgrading to RHEL10.

This commit in particular takes care of scanning the PAM service folder
to detect whether pam_userdb is used and the location of the database in
use. This information is stored in a model that will be consumed by
another actor later in the upgrade process.

It also includes the unit-tests, and the required files to setup a fake
testing environment.

Signed-off-by: Iker Pedrosa <[email protected]>

repos/system_upgrade/el9toel10/actors/scanpamuserdb/actor.py

@@ -0,0 +1,18 @@
+from leapp.actors import Actor
+from leapp.tags import FactsPhaseTag, IPUWorkflowTag
+from leapp.models import PamUserDbLocation
+from leapp.libraries.actor import scanpamuserdb
+
+
+class ScanPamUserDb(Actor):
+    """
+    Scan the PAM service folder for the location of pam_userdb databases
+    """
+
+    name = 'scan_pam_user_db'
+    consumes = ()
+    produces = (PamUserDbLocation,)
+    tags = (FactsPhaseTag, IPUWorkflowTag)
+
+    def process(self):
+        self.produce(scanpamuserdb.parse_folder('/etc/pam.d/'))

repos/system_upgrade/el9toel10/actors/scanpamuserdb/libraries/scanpamuserdb.py

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+import os
+import re
+
+from leapp.models import PamUserDbLocation
+
+
+def parse_file(conf_file):
+    with open(conf_file, 'r') as file:
+        for line in file:
+            if 'pam_userdb' in line:
+                match = re.search(r'db=(\S+)', line)
+                if match:
+                    return match.group(1)
+
+    return None
+
+
+def parse_folder(conf_folder):
+    locations = set()
+
+    for file_name in os.listdir(conf_folder):
+        file_path = os.path.join(conf_folder, file_name)
+
+        if os.path.isfile(file_path):
+            location = parse_file(file_path)
+            if location is not None:
+                locations.add(location)
+
+    return PamUserDbLocation(locations=list(locations))

repos/system_upgrade/el9toel10/actors/scanpamuserdb/tests/files/pam_userdb_basic

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+auth   required    pam_userdb.so    db=/tmp/db1

repos/system_upgrade/el9toel10/actors/scanpamuserdb/tests/files/pam_userdb_complete

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+auth        required                                     pam_env.so
+auth        required                                     pam_faildelay.so delay=2000000
+auth        sufficient                                   pam_fprintd.so
+auth        [default=1 ignore=ignore success=ok]         pam_usertype.so isregular
+auth        [default=1 ignore=ignore success=ok]         pam_localuser.so
+auth        required                                     pam_userdb.so db=/tmp/db2
+auth        [default=1 ignore=ignore success=ok]         pam_usertype.so isregular
+auth        sufficient                                   pam_sss.so forward_pass
+auth        required                                     pam_deny.so

repos/system_upgrade/el9toel10/actors/scanpamuserdb/tests/files/pam_userdb_missing

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+auth        sufficient                                   pam_unix.so nullok

repos/system_upgrade/el9toel10/actors/scanpamuserdb/tests/test_scanpamuserdb.py

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+import os
+
+import pytest
+
+from leapp.libraries.actor import scanpamuserdb
+
+CUR_DIR = os.path.dirname(os.path.abspath(__file__))
+
+
+def test_parse_file():
+    file = scanpamuserdb.parse_file(os.path.join(CUR_DIR, 'files/pam_userdb_missing'))
+    assert file is None
+    file = scanpamuserdb.parse_file(os.path.join(CUR_DIR, 'files/pam_userdb_basic'))
+    assert file == '/tmp/db1'
+    file = scanpamuserdb.parse_file(os.path.join(CUR_DIR, 'files/pam_userdb_complete'))
+    assert file == '/tmp/db2'
+
+
+def test_parse_folder():
+    msg = scanpamuserdb.parse_folder(os.path.join(CUR_DIR, 'files/'))
+    assert len(msg.locations) == 2
+    assert '/tmp/db1' in msg.locations
+    assert '/tmp/db2' in msg.locations

repos/system_upgrade/el9toel10/models/pamuserdblocation.py

@@ -0,0 +1,14 @@
+from leapp.models import Model, fields
+from leapp.topics import SystemInfoTopic
+
+
+class PamUserDbLocation(Model):
+    """
+    Provides a list of all database files for pam_userdb
+    """
+    topic = SystemInfoTopic
+
+    locations = fields.List(fields.String(), default=[])
+    """
+    The list with the full path to the database files.
+    """