expose linux extended file system attributes (closes #12720)

This commit is contained in:
Benjamin Peterson 2011-08-31 22:15:17 -04:00
parent ab3bea6815
commit 799bd80d8a
6 changed files with 649 additions and 2 deletions

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@ -751,6 +751,26 @@ as internal buffering of data.
This function is not available on MacOS.
.. function:: fgetxattr(fd, attr)
This works exactly like :func:`getxattr` but operates on a file descriptor,
*fd*, instead of a path.
Availability: Linux
.. versionadded:: 3.3
.. function:: flistxattr(fd)
This is exactly like :func:`listxattr` but operates on a file descriptor,
*fd*, instead of a path.
Availability: Linux
.. versionadded:: 3.3
.. function:: fdlistdir(fd)
Like :func:`listdir`, but uses a file descriptor instead and always returns
@ -836,6 +856,27 @@ as internal buffering of data.
Availability: Unix.
.. function:: fremovexattr(fd, attr)
This works exactly like :func:`removexattr` but operates on a file
descriptor, *fd*, instead of a path.
Availability: Linux
.. versionadded:: 3.3
.. function:: fsetxattr(fd, attr, value, flags=0)
This works exactly like :func:`setxattr` but on a file descriptor, *fd*,
instead of a path.
Availability: Linux
.. versionadded:: 3.3
.. function:: futimesat(dirfd, path, (atime, mtime))
futimesat(dirfd, path, None)
@ -1536,6 +1577,17 @@ Files and Directories
Availability: Unix.
.. function:: getxattr(path, attr)
Return the value of the extended filesystem attribute *attr* for
*path*. *attr* can be bytes or str. If it is str, it is encoded with the
filesystem encoding.
Availability: Linux
.. versionadded:: 3.3
.. function:: lchflags(path, flags)
Set the flags of *path* to the numeric *flags*, like :func:`chflags`, but do not
@ -1561,6 +1613,15 @@ Files and Directories
Availability: Unix.
.. function:: lgetxattr(path, attr)
This works exactly like :func:`getxattr` but doesn't follow symlinks.
Availability: Linux
.. versionadded:: 3.3
.. function:: link(source, link_name)
Create a hard link pointing to *source* named *link_name*.
@ -1585,6 +1646,44 @@ Files and Directories
.. versionchanged:: 3.2
The *path* parameter became optional.
.. function:: listxattr(path)
Return a list of the extended filesystem attributes on *path*. Attributes are
returned as string decoded with the filesystem encoding.
Availability: Linux
.. versionadded:: 3.3
.. function:: llistxattr(path)
This works exactly like :func:`listxattr` but doesn't follow symlinks.
Availability: Linux
.. versionadded:: 3.3
.. function:: lremoveattr(path, attr)
This works exactly like :func:`removeattr` but doesn't follow symlinks.
Availability: Linux
.. versionadded:: 3.3
.. function:: lsetxattr(path, attr, value, flags=0)
This works exactly like :func:`setxattr` but doesn't follow symlinks.
Availability: Linux
.. versionadded:: 3.3
.. function:: lstat(path)
Perform the equivalent of an :c:func:`lstat` system call on the given path.
@ -1758,6 +1857,17 @@ Files and Directories
successfully removed.
.. function:: removexattr(path, attr)
Removes the extended filesystem attribute *attr* from *path*. *attr* should
be bytes or str. If it is a string, it is encoded with the filesystem
encoding.
Availability: Linux
.. versionadded:: 3.3
.. function:: rename(src, dst)
Rename the file or directory *src* to *dst*. If *dst* is a directory,
@ -1794,6 +1904,44 @@ Files and Directories
Availability: Unix, Windows.
.. data:: XATTR_SIZE_MAX
The maximum size the value of an extended attribute can be. Currently, this
is 64 kilobytes on Linux.
.. data:: XATTR_CREATE
This is a possible value for the flags argument in :func:`setxattr`. It
indicates the operation must create an attribute.
.. data:: XATTR_REPLACE
This is a possible value for the flags argument in :func:`setxattr`. It
indicates the operation must replace an existing attribute.
.. function:: setxattr(path, attr, value, flags=0)
Set the extended filesystem attribute *attr* on *path* to *value*. *attr*
must be a bytes or str with no embedded NULs. If it is str, it is encoded
with the filesystem encoding. *flags* may be :data:`XATTR_REPLACE` or
:data:`XATTR_CREATE`. If :data:`XATTR_REPLACE` is given and the attribute
does not exist, ``EEXISTS`` will be raised. If :data:`XATTR_CREATE` is given
and the attribute already exists, the attribute will not be created and
``ENODATA`` will be raised.
Availability: Linux
.. note::
A bug in Linux kernel versions less than 2.6.39 caused the flags argument
to be ignored on some filesystems.
.. versionadded:: 3.3
.. function:: stat(path)
Perform the equivalent of a :c:func:`stat` system call on the given path.

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@ -14,6 +14,8 @@ import shutil
from test import support
import contextlib
import mmap
import platform
import re
import uuid
import asyncore
import asynchat
@ -1506,6 +1508,97 @@ class TestSendfile(unittest.TestCase):
raise
def supports_extended_attributes():
if not hasattr(os, "setxattr"):
return False
try:
with open(support.TESTFN, "wb") as fp:
try:
os.fsetxattr(fp.fileno(), b"user.test", b"")
except OSError as e:
if e.errno != errno.ENOTSUP:
raise
return False
finally:
support.unlink(support.TESTFN)
# Kernels < 2.6.39 don't respect setxattr flags.
kernel_version = platform.release()
m = re.match("2.6.(\d{1,2})", kernel_version)
return m is None or int(m.group(1)) >= 39
@unittest.skipUnless(supports_extended_attributes(),
"no non-broken extended attribute support")
class ExtendedAttributeTests(unittest.TestCase):
def tearDown(self):
support.unlink(support.TESTFN)
def _check_xattrs_str(self, s, getxattr, setxattr, removexattr, listxattr):
fn = support.TESTFN
open(fn, "wb").close()
with self.assertRaises(OSError) as cm:
getxattr(fn, s("user.test"))
self.assertEqual(cm.exception.errno, errno.ENODATA)
self.assertEqual(listxattr(fn), [])
setxattr(fn, s("user.test"), b"")
self.assertEqual(listxattr(fn), ["user.test"])
self.assertEqual(getxattr(fn, b"user.test"), b"")
setxattr(fn, s("user.test"), b"hello", os.XATTR_REPLACE)
self.assertEqual(getxattr(fn, b"user.test"), b"hello")
with self.assertRaises(OSError) as cm:
setxattr(fn, s("user.test"), b"bye", os.XATTR_CREATE)
self.assertEqual(cm.exception.errno, errno.EEXIST)
with self.assertRaises(OSError) as cm:
setxattr(fn, s("user.test2"), b"bye", os.XATTR_REPLACE)
self.assertEqual(cm.exception.errno, errno.ENODATA)
setxattr(fn, s("user.test2"), b"foo", os.XATTR_CREATE)
self.assertEqual(sorted(listxattr(fn)), ["user.test", "user.test2"])
removexattr(fn, s("user.test"))
with self.assertRaises(OSError) as cm:
getxattr(fn, s("user.test"))
self.assertEqual(cm.exception.errno, errno.ENODATA)
self.assertEqual(listxattr(fn), ["user.test2"])
self.assertEqual(getxattr(fn, s("user.test2")), b"foo")
setxattr(fn, s("user.test"), b"a"*1024)
self.assertEqual(getxattr(fn, s("user.test")), b"a"*1024)
removexattr(fn, s("user.test"))
many = sorted("user.test{}".format(i) for i in range(100))
for thing in many:
setxattr(fn, thing, b"x")
self.assertEqual(sorted(listxattr(fn)), many)
def _check_xattrs(self, *args):
def make_bytes(s):
return bytes(s, "ascii")
self._check_xattrs_str(str, *args)
support.unlink(support.TESTFN)
self._check_xattrs_str(make_bytes, *args)
def test_simple(self):
self._check_xattrs(os.getxattr, os.setxattr, os.removexattr,
os.listxattr)
def test_lpath(self):
self._check_xattrs(os.lgetxattr, os.lsetxattr, os.lremovexattr,
os.llistxattr)
def test_fds(self):
def getxattr(path, *args):
with open(path, "rb") as fp:
return os.fgetxattr(fp.fileno(), *args)
def setxattr(path, *args):
with open(path, "wb") as fp:
os.fsetxattr(fp.fileno(), *args)
def removexattr(path, *args):
with open(path, "wb") as fp:
os.fremovexattr(fp.fileno(), *args)
def listxattr(path, *args):
with open(path, "rb") as fp:
return os.flistxattr(fp.fileno(), *args)
self._check_xattrs(getxattr, setxattr, removexattr, listxattr)
@support.reap_threads
def test_main():
support.run_unittest(
@ -1529,6 +1622,7 @@ def test_main():
LinkTests,
TestSendfile,
ProgramPriorityTests,
ExtendedAttributeTests,
)
if __name__ == "__main__":

View File

@ -107,6 +107,10 @@ corresponding Unix manual entries for more information on calls.");
#include <sched.h>
#endif
#ifdef HAVE_ATTR_XATTR_H
#include <attr/xattr.h>
#endif
#if defined(__FreeBSD__) || defined(__DragonFly__) || defined(__APPLE__)
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
@ -9950,6 +9954,384 @@ posix_mkfifoat(PyObject *self, PyObject *args)
}
#endif
#ifdef HAVE_ATTR_XATTR_H
static int
try_getxattr(const char *path, const char *name,
ssize_t (*get)(const char *, const char *, void *, size_t),
Py_ssize_t buf_size, PyObject **res)
{
PyObject *value;
Py_ssize_t len;
assert(buf_size <= XATTR_SIZE_MAX);
value = PyBytes_FromStringAndSize(NULL, buf_size);
if (!value)
return 0;
Py_BEGIN_ALLOW_THREADS;
len = get(path, name, PyBytes_AS_STRING(value), buf_size);
Py_END_ALLOW_THREADS;
if (len < 0) {
Py_DECREF(value);
if (errno == ERANGE) {
value = NULL;
}
else {
posix_error();
return 0;
}
}
else if (len != buf_size) {
/* Can only shrink. */
_PyBytes_Resize(&value, len);
}
*res = value;
return 1;
}
static PyObject *
getxattr_common(const char *path, PyObject *name_obj,
ssize_t (*get)(const char *, const char *, void *, size_t))
{
PyObject *value;
const char *name = PyBytes_AS_STRING(name_obj);
/* Try a small value first. */
if (!try_getxattr(path, name, get, 128, &value))
return NULL;
if (value)
return value;
/* Now the maximum possible one. */
if (!try_getxattr(path, name, get, XATTR_SIZE_MAX, &value))
return NULL;
assert(value);
return value;
}
PyDoc_STRVAR(posix_getxattr__doc__,
"getxattr(path, attr) -> value\n\n\
Return the value of extended attribute *name* on *path*.");
static PyObject *
posix_getxattr(PyObject *self, PyObject *args)
{
PyObject *path, *res, *name;
if (!PyArg_ParseTuple(args, "O&O&:getxattr", PyUnicode_FSConverter, &path,
PyUnicode_FSConverter, &name))
return NULL;
res = getxattr_common(PyBytes_AS_STRING(path), name, getxattr);
Py_DECREF(path);
Py_DECREF(name);
return res;
}
PyDoc_STRVAR(posix_lgetxattr__doc__,
"lgetxattr(path, attr) -> value\n\n\
Like getxattr but don't follow symlinks.");
static PyObject *
posix_lgetxattr(PyObject *self, PyObject *args)
{
PyObject *path, *res, *name;
if (!PyArg_ParseTuple(args, "O&O&:lgetxattr", PyUnicode_FSConverter, &path,
PyUnicode_FSConverter, &name))
return NULL;
res = getxattr_common(PyBytes_AS_STRING(path), name, lgetxattr);
Py_DECREF(path);
Py_DECREF(name);
return res;
}
static ssize_t
wrap_fgetxattr(const char *path, const char *name, void *value, size_t size)
{
/* Hack to share code. */
return fgetxattr((int)(Py_uintptr_t)path, name, value, size);
}
PyDoc_STRVAR(posix_fgetxattr__doc__,
"fgetxattr(fd, attr) -> value\n\n\
Like getxattr but operate on a fd instead of a path.");
static PyObject *
posix_fgetxattr(PyObject *self, PyObject *args)
{
PyObject *res, *name;
int fd;
if (!PyArg_ParseTuple(args, "iO&:fgetxattr", &fd, PyUnicode_FSConverter, &name))
return NULL;
res = getxattr_common((const char *)(Py_uintptr_t)fd, name, wrap_fgetxattr);
Py_DECREF(name);
return res;
}
PyDoc_STRVAR(posix_setxattr__doc__,
"setxattr(path, attr, value, flags=0)\n\n\
Set extended attribute *attr* on *path* to *value*.");
static PyObject *
posix_setxattr(PyObject *self, PyObject *args)
{
PyObject *path, *name;
Py_buffer data;
int flags = 0, err;
if (!PyArg_ParseTuple(args, "O&O&y*|i:setxattr", PyUnicode_FSConverter,
&path, PyUnicode_FSConverter, &name, &data, &flags))
return NULL;
Py_BEGIN_ALLOW_THREADS;
err = setxattr(PyBytes_AS_STRING(path), PyBytes_AS_STRING(name),
data.buf, data.len, flags);
Py_END_ALLOW_THREADS;
Py_DECREF(path);
Py_DECREF(name);
PyBuffer_Release(&data);
if (err)
return posix_error();
Py_RETURN_NONE;
}
PyDoc_STRVAR(posix_lsetxattr__doc__,
"lsetxattr(path, attr, value, flags=0)\n\n\
Like setxattr but don't follow symlinks.");
static PyObject *
posix_lsetxattr(PyObject *self, PyObject *args)
{
PyObject *path, *name;
Py_buffer data;
int flags = 0, err;
if (!PyArg_ParseTuple(args, "O&O&y*|i:lsetxattr", PyUnicode_FSConverter,
&path, PyUnicode_FSConverter, &name, &data, &flags))
return NULL;
Py_BEGIN_ALLOW_THREADS;
err = lsetxattr(PyBytes_AS_STRING(path), PyBytes_AS_STRING(name),
data.buf, data.len, flags);
Py_END_ALLOW_THREADS;
Py_DECREF(path);
Py_DECREF(name);
PyBuffer_Release(&data);
if (err)
return posix_error();
Py_RETURN_NONE;
}
PyDoc_STRVAR(posix_fsetxattr__doc__,
"fsetxattr(fd, attr, value, flags=0)\n\n\
Like setxattr but operates on *fd* instead of a path.");
static PyObject *
posix_fsetxattr(PyObject *self, PyObject *args)
{
Py_buffer data;
const char *name;
int fd, flags = 0, err;
if (!PyArg_ParseTuple(args, "iO&y*|i:fsetxattr", &fd, PyUnicode_FSConverter,
&name, &data, &flags))
return NULL;
Py_BEGIN_ALLOW_THREADS;
err = fsetxattr(fd, PyBytes_AS_STRING(name), data.buf, data.len, flags);
Py_END_ALLOW_THREADS;
Py_DECREF(name);
PyBuffer_Release(&data);
if (err)
return posix_error();
Py_RETURN_NONE;
}
PyDoc_STRVAR(posix_removexattr__doc__,
"removexattr(path, attr)\n\n\
Remove extended attribute *attr* on *path*.");
static PyObject *
posix_removexattr(PyObject *self, PyObject *args)
{
PyObject *path, *name;
int err;
if (!PyArg_ParseTuple(args, "O&O&:removexattr", PyUnicode_FSConverter, &path,
PyUnicode_FSConverter, &name))
return NULL;
Py_BEGIN_ALLOW_THREADS;
err = removexattr(PyBytes_AS_STRING(path), PyBytes_AS_STRING(name));
Py_END_ALLOW_THREADS;
Py_DECREF(path);
Py_DECREF(name);
if (err)
return posix_error();
Py_RETURN_NONE;
}
PyDoc_STRVAR(posix_lremovexattr__doc__,
"lremovexattr(path, attr)\n\n\
Like removexattr but don't follow symlinks.");
static PyObject *
posix_lremovexattr(PyObject *self, PyObject *args)
{
PyObject *path, *name;
int err;
if (!PyArg_ParseTuple(args, "O&O&:lremovexattr", PyUnicode_FSConverter, &path,
PyUnicode_FSConverter, &name))
return NULL;
Py_BEGIN_ALLOW_THREADS;
err = lremovexattr(PyBytes_AS_STRING(path), PyBytes_AS_STRING(name));
Py_END_ALLOW_THREADS;
Py_DECREF(path);
Py_DECREF(name);
if (err)
return posix_error();
Py_RETURN_NONE;
}
PyDoc_STRVAR(posix_fremovexattr__doc__,
"fremovexattr(fd, attr)\n\n\
Like removexattr but operates on a file descriptor.");
static PyObject *
posix_fremovexattr(PyObject *self, PyObject *args)
{
PyObject *name;
int fd, err;
if (!PyArg_ParseTuple(args, "iO&:fremovexattr", &fd,
PyUnicode_FSConverter, &name))
return NULL;
Py_BEGIN_ALLOW_THREADS;
err = fremovexattr(fd, PyBytes_AS_STRING(name));
Py_END_ALLOW_THREADS;
Py_DECREF(name);
if (err)
return posix_error();
Py_RETURN_NONE;
}
static Py_ssize_t
try_listxattr(const char *path, ssize_t (*list)(const char *, char *, size_t),
Py_ssize_t buf_size, char **buf)
{
Py_ssize_t len;
*buf = PyMem_MALLOC(buf_size);
if (!*buf) {
PyErr_NoMemory();
return -1;
}
Py_BEGIN_ALLOW_THREADS;
len = list(path, *buf, buf_size);
Py_END_ALLOW_THREADS;
if (len < 0) {
PyMem_FREE(*buf);
if (errno != ERANGE)
posix_error();
return -1;
}
return len;
}
static PyObject *
listxattr_common(const char *path, ssize_t (*list)(const char *, char *, size_t))
{
PyObject *res, *attr;
Py_ssize_t len, err, start, i;
char *buf;
len = try_listxattr(path, list, 256, &buf);
if (len < 0) {
if (PyErr_Occurred())
return NULL;
len = try_listxattr(path, list, XATTR_LIST_MAX, &buf);
if (len < 0)
return NULL;
}
res = PyList_New(0);
if (!res) {
PyMem_FREE(buf);
return NULL;
}
for (start = i = 0; i < len; i++) {
if (!buf[i]) {
attr = PyUnicode_DecodeFSDefaultAndSize(&buf[start], i - start);
if (!attr) {
Py_DECREF(res);
PyMem_FREE(buf);
return NULL;
}
err = PyList_Append(res, attr);
Py_DECREF(attr);
if (err) {
Py_DECREF(res);
PyMem_FREE(buf);
return NULL;
}
start = i + 1;
}
}
PyMem_FREE(buf);
return res;
}
PyDoc_STRVAR(posix_listxattr__doc__,
"listxattr(path)\n\n\
Return a list of extended attributes on *path*.");
static PyObject *
posix_listxattr(PyObject *self, PyObject *args)
{
PyObject *path, *res;
if (!PyArg_ParseTuple(args, "O&:listxattr", PyUnicode_FSConverter, &path))
return NULL;
res = listxattr_common(PyBytes_AS_STRING(path), listxattr);
Py_DECREF(path);
return res;
}
PyDoc_STRVAR(posix_llistxattr__doc__,
"llistxattr(path)\n\n\
Like listxattr but don't follow symlinks..");
static PyObject *
posix_llistxattr(PyObject *self, PyObject *args)
{
PyObject *path, *res;
if (!PyArg_ParseTuple(args, "O&:llistxattr", PyUnicode_FSConverter, &path))
return NULL;
res = listxattr_common(PyBytes_AS_STRING(path), llistxattr);
Py_DECREF(path);
return res;
}
static ssize_t
wrap_flistxattr(const char *path, char *buf, size_t len)
{
/* Hack to share code. */
return flistxattr((int)(Py_uintptr_t)path, buf, len);
}
PyDoc_STRVAR(posix_flistxattr__doc__,
"flistxattr(path)\n\n\
Like flistxattr but operates on a file descriptor.");
static PyObject *
posix_flistxattr(PyObject *self, PyObject *args)
{
long fd;
if (!PyArg_ParseTuple(args, "i:flistxattr", &fd))
return NULL;
return listxattr_common((const char *)(Py_uintptr_t)fd, wrap_flistxattr);
}
#endif /* HAVE_ATTR_XATTR_H */
static PyMethodDef posix_methods[] = {
{"access", posix_access, METH_VARARGS, posix_access__doc__},
#ifdef HAVE_TTYNAME
@ -10398,6 +10780,20 @@ static PyMethodDef posix_methods[] = {
#endif
#ifdef HAVE_MKFIFOAT
{"mkfifoat", posix_mkfifoat, METH_VARARGS, posix_mkfifoat__doc__},
#endif
#ifdef HAVE_ATTR_XATTR_H
{"setxattr", posix_setxattr, METH_VARARGS, posix_setxattr__doc__},
{"lsetxattr", posix_lsetxattr, METH_VARARGS, posix_lsetxattr__doc__},
{"fsetxattr", posix_fsetxattr, METH_VARARGS, posix_fsetxattr__doc__},
{"getxattr", posix_getxattr, METH_VARARGS, posix_getxattr__doc__},
{"lgetxattr", posix_lgetxattr, METH_VARARGS, posix_lgetxattr__doc__},
{"fgetxattr", posix_fgetxattr, METH_VARARGS, posix_fgetxattr__doc__},
{"removexattr", posix_removexattr, METH_VARARGS, posix_removexattr__doc__},
{"lremovexattr", posix_lremovexattr, METH_VARARGS, posix_lremovexattr__doc__},
{"fremovexattr", posix_fremovexattr, METH_VARARGS, posix_fremovexattr__doc__},
{"listxattr", posix_listxattr, METH_VARARGS, posix_listxattr__doc__},
{"llistxattr", posix_llistxattr, METH_VARARGS, posix_llistxattr__doc__},
{"flistxattr", posix_flistxattr, METH_VARARGS, posix_flistxattr__doc__},
#endif
{NULL, NULL} /* Sentinel */
};
@ -10848,6 +11244,12 @@ all_ins(PyObject *d)
#endif
#endif
#ifdef HAVE_ATTR_XATTR_H
if (ins(d, "XATTR_CREATE", (long)XATTR_CREATE)) return -1;
if (ins(d, "XATTR_REPLACE", (long)XATTR_REPLACE)) return -1;
if (ins(d, "XATTR_SIZE_MAX", (long)XATTR_SIZE_MAX)) return -1;
#endif
#if defined(PYOS_OS2)
if (insertvalues(d)) return -1;
#endif

2
configure vendored
View File

@ -6090,7 +6090,7 @@ $as_echo "#define STDC_HEADERS 1" >>confdefs.h
fi
for ac_header in asm/types.h conio.h curses.h direct.h dlfcn.h errno.h \
for ac_header in asm/types.h attr/xattr.h conio.h curses.h direct.h dlfcn.h errno.h \
fcntl.h grp.h \
ieeefp.h io.h langinfo.h libintl.h ncurses.h poll.h process.h pthread.h \
sched.h shadow.h signal.h stdint.h stropts.h termios.h \

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@ -1299,7 +1299,7 @@ dnl AC_MSG_RESULT($cpp_type)
# checks for header files
AC_HEADER_STDC
AC_CHECK_HEADERS(asm/types.h conio.h curses.h direct.h dlfcn.h errno.h \
AC_CHECK_HEADERS(asm/types.h attr/xattr.h conio.h curses.h direct.h dlfcn.h errno.h \
fcntl.h grp.h \
ieeefp.h io.h langinfo.h libintl.h ncurses.h poll.h process.h pthread.h \
sched.h shadow.h signal.h stdint.h stropts.h termios.h \

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@ -64,6 +64,9 @@
/* Define if GCC supports __attribute__((format(PyArg_ParseTuple, 2, 3))) */
#undef HAVE_ATTRIBUTE_FORMAT_PARSETUPLE
/* Define to 1 if you have the <attr/xattr.h> header file. */
#undef HAVE_ATTR_XATTR_H
/* Define to 1 if you have the `bind_textdomain_codeset' function. */
#undef HAVE_BIND_TEXTDOMAIN_CODESET