agent: Add is_not_symlink_filter()

Adds a filter that can be used with filter_files() to return only files
that are not symlinks.

monkey/infection_monkey/utils/dir_utils.py

@@ -19,3 +19,7 @@ def file_extension_filter(file_extensions: Set):
         return f.suffix in file_extensions
 
     return inner_filter
+
+
+def is_not_symlink_filter(f: Path):
+    return not f.is_symlink()

monkey/tests/unit_tests/infection_monkey/utils/test_dir_utils.py

@@ -1,7 +1,13 @@
+import os
+
+import pytest
+from tests.utils import is_user_admin
+
 from infection_monkey.utils.dir_utils import (
     file_extension_filter,
     filter_files,
     get_all_regular_files_in_directory,
+    is_not_symlink_filter,
 )
 
 FILES = ["file.jpg.zip", "file.xyz", "1.tar", "2.tgz", "2.png", "2.mpg"]
@@ -91,3 +97,19 @@ def test_file_extension_filter(tmp_path):
     filtered_files = filter_files(files_in_dir, [file_extension_filter(valid_extensions)])
 
     assert sorted(files[0:2]) == sorted(filtered_files)
+
+
+@pytest.mark.skipif(
+    os.name == "nt" and not is_user_admin(), reason="Test requires admin rights on Windows"
+)
+def test_is_not_symlink_filter(tmp_path):
+    files = add_files_to_dir(tmp_path)
+    link_path = tmp_path / "symlink.test"
+    link_path.symlink_to(files[0], target_is_directory=False)
+
+    files_in_dir = get_all_regular_files_in_directory(tmp_path)
+    filtered_files = filter_files(files_in_dir, [is_not_symlink_filter])
+
+    assert link_path in files_in_dir
+    assert len(filtered_files) == len(FILES)
+    assert link_path not in filtered_files

monkey/tests/utils.py

@@ -0,0 +1,9 @@
+import ctypes
+import os
+
+
+def is_user_admin():
+    if os.name == "posix":
+        return os.getuid() == 0
+
+    return ctypes.windll.shell32.IsUserAnAdmin()