sql: test read-write permissions for given path and raise early

maybe fix #6485

electrum/sql_db.py

@@ -6,6 +6,7 @@ import asyncio
 import sqlite3
 
 from .logging import Logger
+from .util import test_read_write_permissions
 
 
 def sql(func):
@@ -17,12 +18,14 @@ def sql(func):
         return f
     return wrapper
 
+
 class SqlDB(Logger):
     
     def __init__(self, asyncio_loop, path, commit_interval=None):
         Logger.__init__(self)
         self.asyncio_loop = asyncio_loop
         self.path = path
+        test_read_write_permissions(path)
         self.commit_interval = commit_interval
         self.db_requests = queue.Queue()
         self.sql_thread = threading.Thread(target=self.run_sql)

electrum/storage.py

@@ -31,7 +31,8 @@ import zlib
 from enum import IntEnum
 
 from . import ecc
-from .util import profiler, InvalidPassword, WalletFileException, bfh, standardize_path
+from .util import (profiler, InvalidPassword, WalletFileException, bfh, standardize_path,
+                   test_read_write_permissions)
 
 from .wallet_db import WalletDB
 from .logging import Logger
@@ -62,7 +63,10 @@ class WalletStorage(Logger):
         self.logger.info(f"wallet path {self.path}")
         self.pubkey = None
         self.decrypted = ''
-        self._test_read_write_permissions(self.path)
+        try:
+            test_read_write_permissions(self.path)
+        except IOError as e:
+            raise StorageReadWriteError(e) from e
         if self.file_exists():
             with open(self.path, "r", encoding='utf-8') as f:
                 self.raw = f.read()
@@ -74,28 +78,6 @@ class WalletStorage(Logger):
     def read(self):
         return self.decrypted if self.is_encrypted() else self.raw
 
-    @classmethod
-    def _test_read_write_permissions(cls, path):
-        # note: There might already be a file at 'path'.
-        #       Make sure we do NOT overwrite/corrupt that!
-        temp_path = "%s.tmptest.%s" % (path, os.getpid())
-        echo = "fs r/w test"
-        try:
-            # test READ permissions for actual path
-            if os.path.exists(path):
-                with open(path, "r", encoding='utf-8') as f:
-                    f.read(1)  # read 1 byte
-            # test R/W sanity for "similar" path
-            with open(temp_path, "w", encoding='utf-8') as f:
-                f.write(echo)
-            with open(temp_path, "r", encoding='utf-8') as f:
-                echo2 = f.read()
-            os.remove(temp_path)
-        except Exception as e:
-            raise StorageReadWriteError(e) from e
-        if echo != echo2:
-            raise StorageReadWriteError('echo sanity-check failed')
-
     @profiler
     def write(self, data):
         s = self.encrypt_before_writing(data)

electrum/util.py

@@ -1465,3 +1465,25 @@ def random_shuffled_copy(x: Iterable[T]) -> List[T]:
     x_copy = list(x)  # copy
     random.shuffle(x_copy)  # shuffle in-place
     return x_copy
+
+
+def test_read_write_permissions(path) -> None:
+    # note: There might already be a file at 'path'.
+    #       Make sure we do NOT overwrite/corrupt that!
+    temp_path = "%s.tmptest.%s" % (path, os.getpid())
+    echo = "fs r/w test"
+    try:
+        # test READ permissions for actual path
+        if os.path.exists(path):
+            with open(path, "rb") as f:
+                f.read(1)  # read 1 byte
+        # test R/W sanity for "similar" path
+        with open(temp_path, "w", encoding='utf-8') as f:
+            f.write(echo)
+        with open(temp_path, "r", encoding='utf-8') as f:
+            echo2 = f.read()
+        os.remove(temp_path)
+    except Exception as e:
+        raise IOError(e) from e
+    if echo != echo2:
+        raise IOError('echo sanity-check failed')