Patch 1329 (partial) by Christian Heimes.

Add a closefd flag to open() which can be set to False to prevent closing
the file descriptor when close() is called or when the object is destroyed.
Useful to ensure that sys.std{in,out,err} keep their file descriptors open
when Python is uninitialized.  (This was always a feature in 2.x, it just
wasn't implemented in 3.0 yet.)

1 files changed, 27 insertions, 9 deletions

diff --git a/Modules/_fileio.c b/Modules/_fileio.c
index bc707e8..8469bb2 100644
--- a/Modules/_fileio.c
+++ b/Modules/_fileio.c
@@ -33,6 +33,7 @@ typedef struct {
 	unsigned readable : 1;
 	unsigned writable : 1;
 	int seekable : 2; /* -1 means unknown */
+	int closefd : 1;
 	PyObject *weakreflist;
 } PyFileIOObject;
 
@@ -59,6 +60,13 @@ internal_close(PyFileIOObject *self)
 static PyObject *
 fileio_close(PyFileIOObject *self)
 {
+	if (!self->closefd) {
+		if (PyErr_WarnEx(PyExc_RuntimeWarning,
+				 "Trying to close unclosable fd!", 3) < 0) {
+			return NULL;
+		}
+		Py_RETURN_NONE;
+	}
 	errno = internal_close(self);
 	if (errno < 0) {
 		PyErr_SetFromErrno(PyExc_IOError);
@@ -119,7 +127,7 @@ static int
 fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)
 {
 	PyFileIOObject *self = (PyFileIOObject *) oself;
-	static char *kwlist[] = {"file", "mode", NULL};
+	static char *kwlist[] = {"file", "mode", "closefd", NULL};
 	char *name = NULL;
 	char *mode = "r";
 	char *s;
@@ -130,6 +138,7 @@ fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)
 	int rwa = 0, plus = 0, append = 0;
 	int flags = 0;
 	int fd = -1;
+	int closefd = 1;
 
 	assert(PyFileIO_Check(oself));
 	if (self->fd >= 0) {
@@ -138,8 +147,8 @@ fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)
 			return -1;
 	}
 
-	if (PyArg_ParseTupleAndKeywords(args, kwds, "i|s:fileio",
-					kwlist, &fd, &mode)) {
+	if (PyArg_ParseTupleAndKeywords(args, kwds, "i|si:fileio",
+					kwlist, &fd, &mode, &closefd)) {
 		if (fd < 0) {
 			PyErr_SetString(PyExc_ValueError,
 					"Negative filedescriptor");
@@ -153,8 +162,9 @@ fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)
 	    if (GetVersion() < 0x80000000) {
 		/* On NT, so wide API available */
 		PyObject *po;
-		if (PyArg_ParseTupleAndKeywords(args, kwds, "U|s:fileio",
-						kwlist, &po, &mode)) {
+		if (PyArg_ParseTupleAndKeywords(args, kwds, "U|si:fileio",
+						kwlist, &po, &mode, &closefd)
+						) {
 			widename = PyUnicode_AS_UNICODE(po);
 		} else {
 			/* Drop the argument parsing error as narrow
@@ -162,13 +172,13 @@ fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)
 			PyErr_Clear();
 		}
 	    }
-	    if (widename == NULL) 
+	    if (widename == NULL)
 #endif
 	    {
-		if (!PyArg_ParseTupleAndKeywords(args, kwds, "et|s:fileio",
+		if (!PyArg_ParseTupleAndKeywords(args, kwds, "et|si:fileio",
 						 kwlist,
 						 Py_FileSystemDefaultEncoding,
-						 &name, &mode))
+						 &name, &mode, &closefd))
 			goto error;
 	    }
 	}
@@ -237,8 +247,16 @@ fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)
 
 	if (fd >= 0) {
 		self->fd = fd;
+		self->closefd = closefd;
 	}
 	else {
+		self->closefd = 1;
+		if (!closefd) {
+			PyErr_SetString(PyExc_ValueError,
+                            "Cannot use closefd=True with file name");
+			goto error;
+		}
+
 		Py_BEGIN_ALLOW_THREADS
 		errno = 0;
 #ifdef MS_WINDOWS
@@ -270,7 +288,7 @@ fileio_dealloc(PyFileIOObject *self)
 	if (self->weakreflist != NULL)
 		PyObject_ClearWeakRefs((PyObject *) self);
 
-	if (self->fd >= 0) {
+	if (self->fd >= 0 && self->closefd) {
 		errno = internal_close(self);
 		if (errno < 0) {
 #ifdef HAVE_STRERROR