From: Jesse Noller <jnoller@gmail.com>
Date: Thu, 2 Apr 2009 04:22:09 +0000 (+0000)
Subject: Issue 3551: Raise ValueError if the size causes ERROR_NO_SYSTEM_RESOURCES
X-Git-Tag: v2.7a1~1603
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=5053fbbb38b7b8bc8207e2d27c32c7b82ce3172f;p=python

Issue 3551: Raise ValueError if the size causes ERROR_NO_SYSTEM_RESOURCES
---

diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
index 5ff94eaea2..18e81a7938 100644
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -710,7 +710,8 @@ Connection objects usually created using :func:`Pipe` -- see also
       Send an object to the other end of the connection which should be read
       using :meth:`recv`.
 
-      The object must be picklable.
+      The object must be picklable.  Very large pickles (approximately 32 MB+,
+      though it depends on the OS) may raise a ValueError exception.
 
    .. method:: recv()
 
@@ -742,7 +743,9 @@ Connection objects usually created using :func:`Pipe` -- see also
       complete message.
 
       If *offset* is given then data is read from that position in *buffer*.  If
-      *size* is given then that many bytes will be read from buffer.
+      *size* is given then that many bytes will be read from buffer.  Very large
+      buffers (approximately 32 MB+, though it depends on the OS) may raise a
+      ValueError exception
 
    .. method:: recv_bytes([maxlength])
 
diff --git a/Misc/NEWS b/Misc/NEWS
index dd8c0ade99..8a500597db 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -202,6 +202,10 @@ Core and Builtins
 Library
 -------
 
+- Issue 3551: Patch multiprocessing to raise a proper exception if the size of the
+  object when writefile is called causes a ERROR_NO_SYSTEM_RESOURCES. Added docs
+  to note the limitation
+
 - unittest.assertNotEqual() now uses the inequality operator (!=) instead 
   of the equality operator.
   
diff --git a/Modules/_multiprocessing/connection.h b/Modules/_multiprocessing/connection.h
index 458d1d3cf3..c2f85635ad 100644
--- a/Modules/_multiprocessing/connection.h
+++ b/Modules/_multiprocessing/connection.h
@@ -131,8 +131,12 @@ connection_sendbytes(ConnectionObject *self, PyObject *args)
 
 	res = conn_send_string(self, buffer + offset, size);
 
-	if (res < 0)
-		return mp_SetError(PyExc_IOError, res);
+	if (res < 0) {
+		if (PyErr_Occurred())
+			return NULL;
+		else
+			return mp_SetError(PyExc_IOError, res);
+	}
 
 	Py_RETURN_NONE;
 }
diff --git a/Modules/_multiprocessing/pipe_connection.c b/Modules/_multiprocessing/pipe_connection.c
index 27e79dda7d..66947c838f 100644
--- a/Modules/_multiprocessing/pipe_connection.c
+++ b/Modules/_multiprocessing/pipe_connection.c
@@ -23,6 +23,12 @@ conn_send_string(ConnectionObject *conn, char *string, size_t length)
 	Py_BEGIN_ALLOW_THREADS
 	ret = WriteFile(conn->handle, string, length, &amount_written, NULL);
 	Py_END_ALLOW_THREADS
+
+	if (ret == 0 && GetLastError() == ERROR_NO_SYSTEM_RESOURCES) {
+		PyErr_Format(PyExc_ValueError, "Cannnot send %" PY_FORMAT_SIZE_T "d bytes over connection", length);
+		return MP_STANDARD_ERROR;
+	}
+
 	return ret ? MP_SUCCESS : MP_STANDARD_ERROR;
 }