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Patch #1407135, bug #1424041, make mmap.mmap(-1, length) work the same

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on both Unix (SVR4 and BSD) and Windows.  Restores behaviour of passing -1
for anonymous memory on Unix.  Use MAP_ANONYMOUS instead of _ANON since
the latter is deprecated according to Linux (gentoo) man pages.

Should we continue to allow mmap.mmap(0, length) to work on Windows?
0 is a valid fd.

Will backport bugfix portions.
This commit is contained in:
Neal Norwitz 2006-02-05 05:45:43 +00:00
parent d1cfc8ade1
commit 0e6bc8c260
5 changed files with 68 additions and 13 deletions
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59
Modules/mmapmodule.c
View file

@ -54,6 +54,11 @@ my_getpagesize(void)
#include <string.h>
#include <sys/types.h>
/* maybe define MAP_ANON in terms of MAP_ANONYMOUS */
#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
# define MAP_ANONYMOUS MAP_ANON
#endif
static PyObject *mmap_module_error;
typedef enum
@ -863,6 +868,7 @@ new_mmap_object(PyObject *self, PyObject *args, PyObject *kwdict)
PyObject *map_size_obj = NULL;
int map_size;
int fd, flags = MAP_SHARED, prot = PROT_WRITE | PROT_READ;
int devzero = -1;
int access = (int)ACCESS_DEFAULT;
static const char *keywords[] = {"fileno", "length",
"flags", "prot",
@ -921,15 +927,41 @@ new_mmap_object(PyObject *self, PyObject *args, PyObject *kwdict)
m_obj->data = NULL;
m_obj->size = (size_t) map_size;
m_obj->pos = (size_t) 0;
m_obj->fd = dup(fd);
if (m_obj->fd == -1) {
Py_DECREF(m_obj);
PyErr_SetFromErrno(mmap_module_error);
return NULL;
if (fd == -1) {
m_obj->fd = -1;
/* Assume the caller wants to map anonymous memory.
This is the same behaviour as Windows. mmap.mmap(-1, size)
on both Windows and Unix map anonymous memory.
*/
#ifdef MAP_ANONYMOUS
/* BSD way to map anonymous memory */
flags |= MAP_ANONYMOUS;
#else
/* SVR4 method to map anonymous memory is to open /dev/zero */
fd = devzero = open("/dev/zero", O_RDWR);
if (devzero == -1) {
Py_DECREF(m_obj);
PyErr_SetFromErrno(mmap_module_error);
return NULL;
}
#endif
} else {
m_obj->fd = dup(fd);
if (m_obj->fd == -1) {
Py_DECREF(m_obj);
PyErr_SetFromErrno(mmap_module_error);
return NULL;
}
}
m_obj->data = mmap(NULL, map_size,
prot, flags,
fd, 0);
if (devzero != -1) {
close(devzero);
}
if (m_obj->data == (char *)-1) {
m_obj->data = NULL;
Py_DECREF(m_obj);
@ -986,8 +1018,15 @@ new_mmap_object(PyObject *self, PyObject *args, PyObject *kwdict)
if (map_size < 0)
return NULL;
/* if an actual filename has been specified */
if (fileno != 0) {
/* assume -1 and 0 both mean invalid filedescriptor
to 'anonymously' map memory.
XXX: fileno == 0 is a valid fd, but was accepted prior to 2.5.
XXX: Should this code be added?
if (fileno == 0)
PyErr_Warn(PyExc_DeprecationWarning,
"don't use 0 for anonymous memory");
*/
if (fileno != -1 && fileno != 0) {
fh = (HANDLE)_get_osfhandle(fileno);
if (fh==(HANDLE)-1) {
PyErr_SetFromErrno(mmap_module_error);
@ -1123,10 +1162,10 @@ PyMODINIT_FUNC
PyDict_SetItemString (dict, "MAP_EXECUTABLE",
PyInt_FromLong(MAP_EXECUTABLE) );
#endif
#ifdef MAP_ANON
PyDict_SetItemString (dict, "MAP_ANON", PyInt_FromLong(MAP_ANON) );
#ifdef MAP_ANONYMOUS
PyDict_SetItemString (dict, "MAP_ANON", PyInt_FromLong(MAP_ANONYMOUS) );
PyDict_SetItemString (dict, "MAP_ANONYMOUS",
PyInt_FromLong(MAP_ANON) );
PyInt_FromLong(MAP_ANONYMOUS) );
#endif
PyDict_SetItemString (dict, "PAGESIZE",