Revert "Update ostree/bootc host system check."

This reverts commit 734aab7 because
it breaks "dnf --installroot".
Related: https://issues.redhat.com/browse/RHEL-49670

dnf/cli/cli.py

@@ -214,12 +214,13 @@ def do_transaction(self, display=()):
             elif 'test' in self.conf.tsflags:
                 logger.info(_("{prog} will only download packages, install gpg keys, and check the "
                               "transaction.").format(prog=dnf.util.MAIN_PROG_UPPER))
-            if dnf.util._is_bootc_host():
-                _bootc_host_msg = _("""
-*** Error: system is configured to be read-only; for more
-*** information run `bootc status` or `ostree admin status`.
+            if dnf.util.is_container():
+                _container_msg = _("""
+*** This system is managed with ostree.  Changes to the system
+*** made with dnf will be lost with the next ostree-based update.
+*** If you do not want to lose these changes, use 'rpm-ostree'.
 """)
-                logger.info(_bootc_host_msg)
+                logger.info(_container_msg)
                 raise CliError(_("Operation aborted."))
 
             if self._promptWanted():

dnf/util.py

@@ -33,11 +33,13 @@
 import functools
 import hawkey
 import itertools
+import json
 import locale
 import logging
 import os
 import pwd
 import shutil
+import subprocess
 import sys
 import tempfile
 import time
@@ -633,15 +635,30 @@ def _name_unset_wrapper(input_name):
     return input_name if input_name else _("<name-unset>")
 
 
-def _is_bootc_host():
+def is_container():
     """Returns true is the system is managed as an immutable container,
        false otherwise.  If msg is True, a warning message is displayed
        for the user.
     """
-    ostree_booted = '/run/ostree-booted'
-    usr = '/usr/'
-    # Check if usr is writtable and we are in a running ostree system.
-    # We want this code to return true only when the system is in locked state. If someone ran
-    # bootc overlay or ostree admin unlock we would want normal DNF path to be ran as it will be
-    # temporary changes (until reboot).
-    return os.path.isfile(ostree_booted) and not os.access(usr, os.W_OK)
+
+    bootc = '/usr/bin/bootc'
+    ostree = '/sysroot/ostree'
+
+    if os.path.isfile(bootc) and os.access(bootc, os.X_OK):
+        p = subprocess.Popen([bootc, "status", "--json"], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        (out, err) = p.communicate()
+
+        if p.returncode == 0:
+            # check the output of 'bootc status'
+            j = json.loads(out)
+
+            # XXX: the API from bootc status is evolving
+            status = j.get("status", "")
+            kind = j.get("kind", "")
+
+            if kind.lower() == "bootchost" and bool(status.get("isContainer", None)):
+                return True
+    elif os.path.isdir(ostree):
+        return True
+
+    return False