fix: multiple platform adaptors concurrency

gateway/pairing.py

@@ -21,6 +21,8 @@ Storage: ~/.hermes/pairing/
 import json
 import os
 import secrets
+import tempfile
+import threading
 import time
 from pathlib import Path
 from typing import Optional
@@ -45,13 +47,29 @@ PAIRING_DIR = get_hermes_dir("platforms/pairing", "pairing")
 
 
 def _secure_write(path: Path, data: str) -> None:
-    """Write data to file with restrictive permissions (owner read/write only)."""
+    """Write data to file with restrictive permissions (owner read/write only).
+
+    Uses a temp-file + atomic rename so readers always see either the old
+    complete file or the new one — never a partial write.
+    """
     path.parent.mkdir(parents=True, exist_ok=True)
-    path.write_text(data, encoding="utf-8")
+    fd, tmp_path = tempfile.mkstemp(dir=str(path.parent), suffix=".tmp")
+    try:
+        with os.fdopen(fd, "w", encoding="utf-8") as f:
+            f.write(data)
+            f.flush()
+            os.fsync(f.fileno())
+        os.replace(tmp_path, str(path))
         try:
             os.chmod(path, 0o600)
         except OSError:
             pass  # Windows doesn't support chmod the same way
+    except BaseException:
+        try:
+            os.unlink(tmp_path)
+        except OSError:
+            pass
+        raise
 
 
 class PairingStore:
@@ -66,6 +84,9 @@ class PairingStore:
 
     def __init__(self):
         PAIRING_DIR.mkdir(parents=True, exist_ok=True)
+        # Protects all read-modify-write cycles. The gateway runs multiple
+        # platform adapters concurrently in threads sharing one PairingStore.
+        self._lock = threading.RLock()
 
     def _pending_path(self, platform: str) -> Path:
         return PAIRING_DIR / f"{platform}-pending.json"
@@ -105,7 +126,7 @@ class PairingStore:
         return results
 
     def _approve_user(self, platform: str, user_id: str, user_name: str = "") -> None:
-        """Add a user to the approved list."""
+        """Add a user to the approved list. Must be called under self._lock."""
         approved = self._load_json(self._approved_path(platform))
         approved[user_id] = {
             "user_name": user_name,
@@ -116,6 +137,7 @@ class PairingStore:
     def revoke(self, platform: str, user_id: str) -> bool:
         """Remove a user from the approved list. Returns True if found."""
         path = self._approved_path(platform)
+        with self._lock:
             approved = self._load_json(path)
             if user_id in approved:
                 del approved[user_id]
@@ -136,6 +158,7 @@ class PairingStore:
           - Max pending codes reached for this platform
           - User/platform is in lockout due to failed attempts
         """
+        with self._lock:
             self._cleanup_expired(platform)
 
             # Check lockout
@@ -173,6 +196,7 @@ class PairingStore:
 
         Returns {user_id, user_name} on success, None if code is invalid/expired.
         """
+        with self._lock:
             self._cleanup_expired(platform)
             code = code.upper().strip()
 
@@ -212,6 +236,7 @@ class PairingStore:
 
     def clear_pending(self, platform: str = None) -> int:
         """Clear all pending requests. Returns count removed."""
+        with self._lock:
             count = 0
             platforms = [platform] if platform else self._all_platforms("pending")
             for p in platforms: