Do not use sudo FQDN lookups

ci/qemu_guest_test.py

@@ -6,6 +6,9 @@
 # These tests are run inside the qemu guest as root using its own pytest runner
 # invocation.
 
+import subprocess
+import tempfile
+
 import pytest
 
 # Mark this module so that the main test runner can skip it when running from
@@ -20,3 +23,69 @@ def test_empty():
     # The empty test. This is nevertheless useful as its presence ensures that
     # the host is calling the guest test suite in this module correctly.
     pass
+
+
+# To keep tests fast for developer iteration, just install all the test
+# dependencies together once for all tests defined here. It is likely that our
+# tests here are not going to interact. If they do, then we can decide whether
+# to compromise on this at that time.
+@pytest.fixture(scope="module")
+def apt_dependencies():
+    # To speed things up, we deliberately skip the apt-get update here on the
+    # assumption that it was arranged by whatever is running the test. This is
+    # arranged from qemu_test.py::test_using_guest_tests() instead.
+    subprocess.run(
+        ["apt-get", "install", "-y", "--no-install-recommends", "sudo", "gdb"],
+        check=True,
+    )
+
+
+@pytest.mark.xfail(
+    reason="https://github.com/qualcomm-linux/qcom-deb-images/issues/193",
+    strict=True,
+)
+def test_sudo_no_fqdn(apt_dependencies):
+    """sudo should not call FQDN lookup functions
+
+    See: https://github.com/qualcomm-linux/qcom-deb-images/issues/193
+    """
+    with tempfile.NamedTemporaryFile(
+        mode="w", delete_on_close=False
+    ) as gdb_commands_file:
+        print(
+            "catch load",
+            "run",
+            "del 1",
+            sep="\n",
+            file=gdb_commands_file,
+        )
+        for fn_name in [
+            "gethostbyaddr",
+            "getnameinfo",
+            "getaddrinfo",
+            "gethostbyname",
+        ]:
+            print(
+                f"break {fn_name}",
+                f"commands",
+                f'    print "{fn_name} called\\n"',
+                f"    quit 1",
+                f"end",
+                sep="\n",
+                file=gdb_commands_file,
+            )
+        print("continue", file=gdb_commands_file)
+        gdb_commands_file.close()
+
+        subprocess.run(
+            [
+                "gdb",
+                "--batch",
+                "-x",
+                gdb_commands_file.name,
+                "--args",
+                "sudo",
+                "true",
+            ],
+            check=True,
+        )