gh-98999: Raise ValueError in _pyio on closed buffers (gh-99009)

Lib/_pyio.py

@@ -1129,6 +1129,7 @@ class BufferedReader(_BufferedIOMixin):
         do at most one raw read to satisfy it.  We never return more
         than self.buffer_size.
         """
+        self._checkClosed("peek of closed file")
         with self._read_lock:
             return self._peek_unlocked(size)
 
@@ -1147,6 +1148,7 @@ class BufferedReader(_BufferedIOMixin):
         """Reads up to size bytes, with at most one read() system call."""
         # Returns up to size bytes.  If at least one byte is buffered, we
         # only return buffered bytes.  Otherwise, we do one raw read.
+        self._checkClosed("read of closed file")
         if size < 0:
             size = self.buffer_size
         if size == 0:
@@ -1164,6 +1166,8 @@ class BufferedReader(_BufferedIOMixin):
     def _readinto(self, buf, read1):
         """Read data into *buf* with at most one system call."""
 
+        self._checkClosed("readinto of closed file")
+
         # Need to create a memoryview object of type 'b', otherwise
         # we may not be able to assign bytes to it, and slicing it
         # would create a new object.
@@ -1213,6 +1217,7 @@ class BufferedReader(_BufferedIOMixin):
     def seek(self, pos, whence=0):
         if whence not in valid_seek_flags:
             raise ValueError("invalid whence value")
+        self._checkClosed("seek of closed file")
         with self._read_lock:
             if whence == 1:
                 pos -= len(self._read_buf) - self._read_pos