Use portalocker for cross-platform locking

.gitattributes

@@ -0,0 +1 @@
+* text eol=lf

.github/workflows/python-ci.yml

@@ -8,7 +8,10 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4

README.md

@@ -11,6 +11,11 @@
 This software was not developed by an experienced security expert and should be used with caution. There may be bugs and missing features. For instance, the maximum size of the index before the Nostr backup starts to have problems is unknown. Additionally, the security of the program's memory management and logs has not been evaluated and may leak sensitive information.
 
 ---
+### Supported OS
+
+✔ Windows 10/11 • macOS 12+ • Any modern Linux  
+SeedPass now uses the `portalocker` library for cross-platform file locking. No WSL or Cygwin required.
+
 
 ## Table of Contents
 
@@ -79,7 +84,7 @@ Activate the virtual environment using the appropriate command for your operatin
   source venv/bin/activate
   ```
 
-- **On Windows:** (Note: SeedPass currently does not support Windows)
+- **On Windows:**
 
   ```bash
   venv\Scripts\activate

src/main.py

@@ -1,5 +1,6 @@
 # main.py
 import os
+from pathlib import Path
 import sys
 import logging
 import signal
@@ -23,13 +24,13 @@ def configure_logging():
         logger.removeHandler(handler)
 
     # Ensure the 'logs' directory exists
-    log_directory = "logs"
-    if not os.path.exists(log_directory):
-        os.makedirs(log_directory)
+    log_directory = Path("logs")
+    if not log_directory.exists():
+        log_directory.mkdir(parents=True, exist_ok=True)
 
     # Create handlers
     c_handler = logging.StreamHandler(sys.stdout)
-    f_handler = logging.FileHandler(os.path.join(log_directory, "main.log"))
+    f_handler = logging.FileHandler(log_directory / "main.log")
 
     # Set levels: only errors and critical messages will be shown in the console
     c_handler.setLevel(logging.ERROR)

src/nostr/client.py

@@ -17,13 +17,12 @@ from monstr.event.event import Event
 
 import threading
 import uuid
-import fcntl
 
 from .key_manager import KeyManager
 from .encryption_manager import EncryptionManager
 from .event_handler import EventHandler
 from constants import APP_DIR
-from utils.file_lock import lock_file
+from utils.file_lock import exclusive_lock
 
 # Get the logger for this module
 logger = logging.getLogger(__name__)
@@ -416,7 +415,7 @@ class NostrClient:
                 json.dumps(data).encode("utf-8")
             )
             index_file_path = self.fingerprint_dir / "seedpass_passwords_db.json.enc"
-            with lock_file(index_file_path, fcntl.LOCK_EX):
+            with exclusive_lock(index_file_path):
                 with open(index_file_path, "wb") as f:
                     f.write(encrypted_data)
             logger.debug(f"Encrypted data saved to {index_file_path}.")
@@ -442,7 +441,7 @@ class NostrClient:
 
             checksum_file = self.fingerprint_dir / "seedpass_passwords_db_checksum.txt"
 
-            with lock_file(checksum_file, fcntl.LOCK_EX):
+            with exclusive_lock(checksum_file):
                 with open(checksum_file, "w") as f:
                     f.write(checksum)
 
@@ -465,7 +464,7 @@ class NostrClient:
         :return: Decrypted data as bytes.
         """
         try:
-            with lock_file(file_path, fcntl.LOCK_SH):
+            with exclusive_lock(file_path):
                 with open(file_path, "rb") as f:
                     encrypted_data = f.read()
             decrypted_data = self.encryption_manager.decrypt_data(encrypted_data)

src/password_manager/backup.py

@@ -16,11 +16,10 @@ import os
 import shutil
 import time
 import traceback
-import fcntl
 from pathlib import Path
 from termcolor import colored
 
-from utils.file_lock import lock_file
+from utils.file_lock import exclusive_lock
 from constants import APP_DIR
 
 # Instantiate the logger
@@ -144,7 +143,7 @@ class BackupManager:
             return
 
         try:
-            with lock_file(backup_file, lock_type=fcntl.LOCK_SH):
+            with exclusive_lock(backup_file):
                 shutil.copy2(backup_file, self.index_file)
             logger.info(f"Restored the index file from backup '{backup_file}'.")
             print(

src/password_manager/encryption.py

@@ -24,8 +24,9 @@ from typing import Optional
 
 from cryptography.fernet import Fernet, InvalidToken
 from termcolor import colored
-from utils.file_lock import lock_file  # Ensure this utility is correctly implemented
-import fcntl  # For file locking
+from utils.file_lock import (
+    exclusive_lock,
+)  # Ensure this utility is correctly implemented
 
 # Instantiate the logger
 logger = logging.getLogger(__name__)
@@ -77,7 +78,7 @@ class EncryptionManager:
             encrypted_data = self.encrypt_data(data)
 
             # Write the encrypted data to the file with locking
-            with lock_file(self.parent_seed_file, fcntl.LOCK_EX):
+            with exclusive_lock(self.parent_seed_file):
                 with open(self.parent_seed_file, "wb") as f:
                     f.write(encrypted_data)
 
@@ -107,7 +108,7 @@ class EncryptionManager:
         """
         try:
             parent_seed_path = self.fingerprint_dir / "parent_seed.enc"
-            with lock_file(parent_seed_path, fcntl.LOCK_SH):
+            with exclusive_lock(parent_seed_path):
                 with open(parent_seed_path, "rb") as f:
                     encrypted_data = f.read()
 
@@ -188,7 +189,7 @@ class EncryptionManager:
             encrypted_data = self.encrypt_data(data)
 
             # Write the encrypted data to the file with locking
-            with lock_file(file_path, fcntl.LOCK_EX):
+            with exclusive_lock(file_path):
                 with open(file_path, "wb") as f:
                     f.write(encrypted_data)
 
@@ -220,7 +221,7 @@ class EncryptionManager:
             file_path = self.fingerprint_dir / relative_path
 
             # Read the encrypted data with locking
-            with lock_file(file_path, fcntl.LOCK_SH):
+            with exclusive_lock(file_path):
                 with open(file_path, "rb") as f:
                     encrypted_data = f.read()
 
@@ -351,7 +352,7 @@ class EncryptionManager:
             checksum_file = file_path.parent / f"{file_path.stem}_checksum.txt"
 
             # Write the checksum to the file with locking
-            with lock_file(checksum_file, fcntl.LOCK_EX):
+            with exclusive_lock(checksum_file):
                 with open(checksum_file, "w") as f:
                     f.write(checksum)
 
@@ -392,7 +393,7 @@ class EncryptionManager:
                 )
                 return None
 
-            with lock_file(self.fingerprint_dir / relative_path, fcntl.LOCK_SH):
+            with exclusive_lock(self.fingerprint_dir / relative_path):
                 with open(self.fingerprint_dir / relative_path, "rb") as file:
                     encrypted_data = file.read()
 

src/password_manager/entry_management.py

@@ -29,9 +29,8 @@ from pathlib import Path
 from termcolor import colored
 
 from password_manager.encryption import EncryptionManager
-from utils.file_lock import lock_file
+from utils.file_lock import exclusive_lock
 
-import fcntl
 
 # Instantiate the logger
 logger = logging.getLogger(__name__)
@@ -407,7 +406,8 @@ class EntryManager:
         :param backup_path: The file path of the backup to restore from.
         """
         try:
-            if not os.path.exists(backup_path):
+            backup_path = Path(backup_path)
+            if not backup_path.exists():
                 logger.error(f"Backup file '{backup_path}' does not exist.")
                 print(
                     colored(

src/requirements.txt

@@ -10,4 +10,5 @@ bcrypt
 bip85
 pytest>=7.0
 pytest-cov
+portalocker>=2.8
 

src/tests/test_file_lock.py

@@ -0,0 +1,36 @@
+import multiprocessing as mp
+import time
+from pathlib import Path
+
+from utils.file_lock import exclusive_lock
+
+
+def _hold_lock(path: Path, hold_time: float, started: mp.Event):
+    with exclusive_lock(path):
+        started.set()
+        time.sleep(hold_time)
+
+
+def _try_lock(path: Path, wait_time: mp.Value):
+    t0 = time.perf_counter()
+    with exclusive_lock(path):
+        wait_time.value = time.perf_counter() - t0
+
+
+def test_exclusive_lock_blocks_until_released(tmp_path: Path):
+    file_path = tmp_path / "locktest.txt"
+
+    started = mp.Event()
+    wait_time = mp.Value("d", 0.0)
+
+    p1 = mp.Process(target=_hold_lock, args=(file_path, 1.0, started))
+    p2 = mp.Process(target=_try_lock, args=(file_path, wait_time))
+
+    p1.start()
+    started.wait()
+    p2.start()
+
+    p1.join()
+    p2.join()
+
+    assert wait_time.value >= 1.0

src/utils/__init__.py

@@ -4,7 +4,7 @@ import logging
 import traceback
 
 try:
-    from .file_lock import lock_file
+    from .file_lock import exclusive_lock
     from .key_derivation import derive_key_from_password, derive_key_from_parent_seed
     from .checksum import calculate_checksum, verify_checksum
     from .password_prompt import prompt_for_password
@@ -19,6 +19,6 @@ __all__ = [
     "derive_key_from_parent_seed",
     "calculate_checksum",
     "verify_checksum",
-    "lock_file",
+    "exclusive_lock",
     "prompt_for_password",
 ]

src/utils/file_lock.py

@@ -1,142 +1,23 @@
-# utils/file_lock.py
-
-"""
-File Lock Module
-
-This module provides a single context manager, `lock_file`, for acquiring and releasing
-locks on files using the `fcntl` library. It ensures that critical files are accessed
-safely, preventing race conditions and maintaining data integrity when multiple processes
-or threads attempt to read from or write to the same file concurrently.
-
-I need to change this to something that supports Windows in the future.
-
-Ensure that all dependencies are installed and properly configured in your environment.
-"""
-
-import os
-import fcntl
-import logging
+"""File-based locking utilities using portalocker for cross-platform support."""
 from contextlib import contextmanager
-from typing import Generator
+from typing import Generator, Optional
 from pathlib import Path
-from termcolor import colored
-import sys
-import traceback
-
-# Instantiate the logger
-logger = logging.getLogger(__name__)
+import portalocker
 
 
 @contextmanager
-def lock_file(file_path: Path, lock_type: int) -> Generator[None, None, None]:
+def exclusive_lock(
+    path: Path, timeout: Optional[float] = None
+) -> Generator[None, None, None]:
+    """Context manager that locks *path* exclusively.
+
+    The function opens the file in binary append mode and obtains an
+    exclusive lock using ``portalocker``. If ``timeout`` is provided,
+    acquiring the lock will wait for at most that many seconds before
+    raising ``portalocker.exceptions.LockException``.
     """
-    Context manager to acquire a lock on a file.
-
-    Parameters:
-        file_path (Path): The path to the file to lock.
-        lock_type (int): The type of lock to acquire (`fcntl.LOCK_EX` for exclusive,
-                         `fcntl.LOCK_SH` for shared).
-
-    Yields:
-        None
-
-    Raises:
-        ValueError: If an invalid lock type is provided.
-        SystemExit: Exits the program if the lock cannot be acquired.
-    """
-    if lock_type not in (fcntl.LOCK_EX, fcntl.LOCK_SH):
-        logging.error(
-            f"Invalid lock type: {lock_type}. Use fcntl.LOCK_EX or fcntl.LOCK_SH."
-        )
-        print(colored("Error: Invalid lock type provided.", "red"))
-        sys.exit(1)
-
-    file = None
-    try:
-        # Determine the mode based on whether the file exists
-        mode = "rb+" if file_path.exists() else "wb"
-
-        # Open the file
-        file = open(file_path, mode)
-        logging.debug(f"Opened file '{file_path}' in mode '{mode}' for locking.")
-
-        # Acquire the lock
-        fcntl.flock(file, lock_type)
-        lock_type_str = "Exclusive" if lock_type == fcntl.LOCK_EX else "Shared"
-        logging.debug(f"{lock_type_str} lock acquired on '{file_path}'.")
-        yield  # Control is transferred to the block inside the `with` statement
-
-    except IOError as e:
-        lock_type_str = "exclusive" if lock_type == fcntl.LOCK_EX else "shared"
-        logging.error(f"Failed to acquire {lock_type_str} lock on '{file_path}': {e}")
-        logging.error(traceback.format_exc())  # Log full traceback
-        print(
-            colored(
-                f"Error: Failed to acquire {lock_type_str} lock on '{file_path}': {e}",
-                "red",
-            )
-        )
-        sys.exit(1)
-
-    finally:
-        if file:
-            try:
-                # Release the lock
-                fcntl.flock(file, fcntl.LOCK_UN)
-                logging.debug(f"Lock released on '{file_path}'.")
-            except Exception as e:
-                lock_type_str = "exclusive" if lock_type == fcntl.LOCK_EX else "shared"
-                logging.warning(
-                    f"Failed to release {lock_type_str} lock on '{file_path}': {e}"
-                )
-                logging.error(traceback.format_exc())  # Log full traceback
-                print(
-                    colored(
-                        f"Warning: Failed to release {lock_type_str} lock on '{file_path}': {e}",
-                        "yellow",
-                    )
-                )
-            finally:
-                # Close the file
-                try:
-                    file.close()
-                    logging.debug(f"File '{file_path}' closed successfully.")
-                except Exception as e:
-                    logging.warning(f"Failed to close file '{file_path}': {e}")
-                    logging.error(traceback.format_exc())  # Log full traceback
-                    print(
-                        colored(
-                            f"Warning: Failed to close file '{file_path}': {e}",
-                            "yellow",
-                        )
-                    )
-
-
-@contextmanager
-def exclusive_lock(file_path: Path) -> Generator[None, None, None]:
-    """
-    Convenience context manager to acquire an exclusive lock on a file.
-
-    Parameters:
-        file_path (Path): The path to the file to lock.
-
-    Yields:
-        None
-    """
-    with lock_file(file_path, fcntl.LOCK_EX):
-        yield
-
-
-@contextmanager
-def shared_lock(file_path: Path) -> Generator[None, None, None]:
-    """
-    Convenience context manager to acquire a shared lock on a file.
-
-    Parameters:
-        file_path (Path): The path to the file to lock.
-
-    Yields:
-        None
-    """
-    with lock_file(file_path, fcntl.LOCK_SH):
-        yield
+    path = Path(path)
+    path.parent.mkdir(parents=True, exist_ok=True)
+    lock = portalocker.Lock(str(path), mode="a+b", timeout=timeout)
+    with lock as fh:
+        yield fh