Change how the user is determined before creating a symlink

- Rather than a filesystem path or environment variables, determine the user via the password database before creating a symbolic link to the steamuser directory -- this is how WINE does it

- See https://github.com/wine-mirror/wine/blob/master/dlls/ntdll/unix/loader.c#L384

- Related to #21 (comment)

ulwgl_run.py

@@ -10,6 +10,7 @@
 import ulwgl_plugins
 from re import match
 import subprocess
+from ulwgl_util import UnixUser
 
 
 def parse_args() -> Union[Namespace, Tuple[str, List[str]]]:  # noqa: D103
@@ -43,14 +44,45 @@ def parse_args() -> Union[Namespace, Tuple[str, List[str]]]:  # noqa: D103
 
 
 def setup_pfx(path: str) -> None:
-    """Create a symlink to the WINE prefix and tracked_files file."""
+    """Create a symlink to the WINE prefix and tracked_files file.
+
+    Also, create a symlink of steamuser to the Unix username
+    """
+    steam: Path = Path(path + "/drive_c/users/steamuser").expanduser()
+    uid: int = os.getuid()
+    user: UnixUser = UnixUser()
+    wineuser: Path = Path(path + "/drive_c/users/" + user.get_user()).expanduser()
+
     if not (Path(path + "/pfx")).expanduser().is_symlink():
         # When creating the symlink, we want it to be in expanded form when passed unexpanded paths
-        # Example: pfx -> /home/foo/.wine
-        # NOTE: When parsing a config file, an error can be raised if the prefix doesn't already exist
+        # Good: pfx -> /home/foo/.wine
+        # Bad: pfx -> ~/.wine
         Path(path + "/pfx").expanduser().symlink_to(Path(path).expanduser())
     Path(path + "/tracked_files").expanduser().touch()
 
+    # Create a symlink of the current user to the steamuser dir for Steam functionality
+    # Only create a symlink for the current user
+    if not wineuser.is_dir() and not steam.is_dir() and user.is_user(uid):
+        steam.mkdir(parents=True)
+        wineuser.symlink_to(steam)
+    elif wineuser.is_dir() and not steam.is_dir() and user.is_user(uid):
+        wineuser.rename(steam)
+        wineuser.symlink_to(steam)
+    elif (
+        not (wineuser.exists() or wineuser.is_symlink())
+        and steam.is_dir()
+        and user.is_user(uid)
+    ):
+        wineuser.symlink_to(steam)
+    elif not user.is_user(uid):
+        print(
+            f"Unable to identify the current user.\nSymbolic link will not be created to path: {steam}"
+        )
+    else:
+        print(
+            f"Paths exist: {steam} and {wineuser}\nPlease consider merging {wineuser} to {steam}."
+        )
+
 
 def check_env(
     env: Dict[str, str], toml: Dict[str, Any] = None

ulwgl_test.py

@@ -866,8 +866,111 @@ def test_set_env(self):
                 "Expected STEAM_COMPAT_MOUNTS to be set",
             )
 
+    def test_setup_pfx_symlinks_steam_mv(self):
+        """Test setup_pfx for symbolic link to steamuser.
+
+        Tests the case when the steamuser dir does not exist and user dir exists
+        In this case, rename the existing user dir to steamuser and create a new symlink to it
+        """
+        result = None
+        pattern = r"^/home/[a-zA-Z]+"
+        unexpanded_path = re.sub(
+            pattern,
+            "~",
+            Path(
+                Path(self.test_file).cwd().as_posix() + "/" + self.test_file
+            ).as_posix(),
+        )
+
+        # Create only the user dir
+        Path(
+            unexpanded_path + "/drive_c/users/" + Path().home().name
+        ).expanduser().mkdir(parents=True, exist_ok=True)
+
+        result = ulwgl_run.setup_pfx(unexpanded_path)
+        self.assertIsNone(
+            result,
+            "Expected None when creating symbolic link to WINE prefix and tracked_files file",
+        )
+        self.assertTrue(
+            Path(self.test_file + "/pfx").is_symlink(), "Expected pfx to be a symlink"
+        )
+        self.assertTrue(
+            Path(self.test_file + "/tracked_files").is_file(),
+            "Expected tracked_files to be a file",
+        )
+        self.assertTrue(
+            Path(self.test_file + "/pfx").is_symlink(), "Expected pfx to be a symlink"
+        )
+        # Check if the symlink is in its unexpanded form
+        self.assertEqual(
+            Path(self.test_file + "/pfx").readlink().as_posix(),
+            Path(unexpanded_path).expanduser().as_posix(),
+        )
+        self.assertTrue(
+            Path(self.test_file + "/drive_c/users/steamuser").is_dir(),
+            "Expected steamuser to be created",
+        )
+        self.assertTrue(
+            Path(unexpanded_path + "/drive_c/users/" + Path().home().name)
+            .expanduser()
+            .is_symlink(),
+            "Expected symlink of username -> steamuser",
+        )
+
+    def test_setup_pfx_symlinks_steam(self):
+        """Test setup_pfx for symbolic link to steamuser.
+
+        Tests the case when the steamuser exists and a user does not exists
+        """
+        result = None
+        pattern = r"^/home/[a-zA-Z]+"
+        unexpanded_path = re.sub(
+            pattern,
+            "~",
+            Path(
+                Path(self.test_file).cwd().as_posix() + "/" + self.test_file
+            ).as_posix(),
+        )
+
+        # Create only the user dir
+        Path(unexpanded_path + "/drive_c/users/steamuser").expanduser().mkdir(
+            parents=True, exist_ok=True
+        )
+        result = ulwgl_run.setup_pfx(unexpanded_path)
+
+        self.assertIsNone(
+            result,
+            "Expected None when creating symbolic link to WINE prefix and tracked_files file",
+        )
+        self.assertTrue(
+            Path(self.test_file + "/pfx").is_symlink(), "Expected pfx to be a symlink"
+        )
+        self.assertTrue(
+            Path(self.test_file + "/tracked_files").is_file(),
+            "Expected tracked_files to be a file",
+        )
+        self.assertTrue(
+            Path(self.test_file + "/pfx").is_symlink(), "Expected pfx to be a symlink"
+        )
+        # Check if the symlink is in its unexpanded form
+        self.assertEqual(
+            Path(self.test_file + "/pfx").readlink().as_posix(),
+            Path(unexpanded_path).expanduser().as_posix(),
+        )
+        self.assertTrue(
+            Path(self.test_file + "/drive_c/users/steamuser").is_dir(),
+            "Expected steamuser to be created",
+        )
+        self.assertTrue(
+            Path(unexpanded_path + "/drive_c/users/" + Path().home().name)
+            .expanduser()
+            .is_symlink(),
+            "Expected symlink of username -> steamuser",
+        )
+
     def test_setup_pfx_symlinks(self):
-        """Test _setup_pfx for valid symlinks.
+        """Test setup_pfx for valid symlinks.
 
         Ensure that symbolic links to the WINE prefix (pfx) are always in expanded form when passed an unexpanded path.
         For example:
@@ -879,6 +982,9 @@ def test_setup_pfx_symlinks(self):
         """
         result = None
         pattern = r"^/home/[a-zA-Z]+"
+
+        # Replaces the expanded path to unexpanded
+        # Example: ~/some/path/to/this/file -> /home/foo/path/to/this/file
         unexpanded_path = re.sub(
             pattern,
             "~",
@@ -888,8 +994,6 @@ def test_setup_pfx_symlinks(self):
         )
         result = ulwgl_run.setup_pfx(unexpanded_path)
 
-        # Replaces the expanded path to unexpanded
-        # Example: ~/some/path/to/this/file -> /home/foo/path/to/this/file
         self.assertIsNone(
             result,
             "Expected None when creating symbolic link to WINE prefix and tracked_files file",
@@ -918,15 +1022,16 @@ def test_setup_pfx_paths(self):
         """
         result = None
         pattern = r"^/home/[a-zA-Z]+"
+
+        # Replaces the expanded path to unexpanded
+        # Example: ~/some/path/to/this/file -> /home/foo/path/to/this/file
         unexpanded_path = re.sub(
             pattern,
             "~",
             Path(Path(self.test_file).as_posix()).as_posix(),
         )
         result = ulwgl_run.setup_pfx(unexpanded_path)
 
-        # Replaces the expanded path to unexpanded
-        # Example: ~/some/path/to/this/file -> /home/foo/path/to/this/file
         self.assertIsNone(
             result,
             "Expected None when creating symbolic link to WINE prefix and tracked_files file",
@@ -954,6 +1059,17 @@ def test_setup_pfx(self):
             Path(self.test_file + "/tracked_files").is_file(),
             "Expected tracked_files to be a file",
         )
+        # For new prefixes, steamuser should exist and a user symlink
+        self.assertTrue(
+            Path(self.test_file + "/drive_c/users/steamuser").is_dir(),
+            "Expected steamuser to be created",
+        )
+        self.assertTrue(
+            Path(self.test_file + "/drive_c/users/" + Path().home().name)
+            .expanduser()
+            .is_symlink(),
+            "Expected symlink of username -> steamuser",
+        )
 
     def test_parse_args(self):
         """Test parse_args with no options.

ulwgl_util.py

@@ -0,0 +1,32 @@
+import os
+import pwd
+from pathlib import Path
+import typing
+from pwd import struct_passwd
+
+class UnixUser:
+    """Represents the User of the system as determined by the password database rather than environment variables or file system paths."""
+
+    def __init__(self):    
+        entry: struct_passwd = pwd.getpwuid(os.getuid())
+        # Immutable properties, hence no setters
+        self.name: str = entry.pw_name
+        self.puid: str = entry.pw_uid # Should be equivalent to the value from getuid
+        self.dir: str = entry.pw_dir
+
+    def get_home_dir(self) -> Path:
+        """The User home directory as determined by the password database that's derived from the current process's real user id."""
+        return Path(self.dir).as_posix()
+
+    def get_user(self) -> str:
+        """The User (login name) as determined by the password database that's derived from the current process's real user id."""
+        return self.name
+
+    def get_puid(self) -> int:
+        """The numerical user ID as determined by the password database that's derived from the current process's real user id."""
+        return self.puid
+
+    def is_user(self, uid: int) -> bool:
+        """Compare the UID passed in to this instance's"""
+        return uid == self.puid
+