[PATCH 1/1] bup_set_linux_file_attr: don't mangle values

[Rob Browning]

I made a mistake in

20a5752021769c3fab183f2646662bdf1b6083fc
Reallow linux attrs on big endian hosts where long > int

that causes the wrong value to be written. Fix it.

Thanks to Johannes Berg for diagnosing the test failure, and help with
the solution.

Signed-off-by: Rob Browning <r...@defaultvalue.org>
Tested-by: Rob Browning <r...@defaultvalue.org>
---

Pushed to main.

lib/bup/_helpers.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/lib/bup/_helpers.c b/lib/bup/_helpers.c
index ba0b6f20..81a74a26 100644
--- a/lib/bup/_helpers.c
+++ b/lib/bup/_helpers.c
@@ -1071,12 +1071,8 @@ static PyObject *bup_set_linux_file_attr(PyObject *self, PyObject *args)
if (!PyArg_ParseTuple(args, cstr_argf "O", &path, &py_attr))
return NULL;

- union {
- unsigned int attr;
- long fuse_had_incorrectly_understandably_used_long; // see above
- } buf;
-
- if (!bup_uint_from_py(&buf.attr, py_attr, "attr"))
+ unsigned int new_attr;
+ if (!bup_uint_from_py(&new_attr, py_attr, "attr"))
return NULL;

int fd = open(path, O_RDONLY | O_NONBLOCK | O_LARGEFILE | O_NOFOLLOW);
@@ -1086,19 +1082,24 @@ static PyObject *bup_set_linux_file_attr(PyObject *self, PyObject *args)
// Restrict attr to modifiable flags acdeijstuADST -- see
// chattr(1) and the e2fsprogs source. Letter to flag mapping is
// in pf.c flags_array[].
- buf.attr &= FS_APPEND_FL | FS_COMPR_FL | FS_NODUMP_FL | FS_EXTENT_FL
+ new_attr &= FS_APPEND_FL | FS_COMPR_FL | FS_NODUMP_FL | FS_EXTENT_FL
| FS_IMMUTABLE_FL | FS_JOURNAL_DATA_FL | FS_SECRM_FL | FS_NOTAIL_FL
| FS_UNRM_FL | FS_NOATIME_FL | FS_DIRSYNC_FL | FS_SYNC_FL
| FS_TOPDIR_FL | FS_NOCOW_FL;

- // The extents flag can't be removed, so don't (see chattr(1) and chattr.c).
+ union {
+ unsigned int attr;
+ long fuse_had_incorrectly_understandably_used_long; // see above
+ } buf;
int rc = ioctl(fd, FS_IOC_GETFLAGS, &buf.attr);
if (rc == -1)
{
close(fd);
return PyErr_SetFromErrnoWithFilename(PyExc_OSError, path);
}
- buf.attr |= buf.attr & FS_EXTENT_FL;
+
+ // The extents flag can't be removed, so don't (see chattr(1) and chattr.c).
+ buf.attr |= new_attr | (buf.attr & FS_EXTENT_FL);

rc = ioctl(fd, FS_IOC_SETFLAGS, &buf.attr);
if (rc == -1)
--
2.47.3