[PATCH 1/7] Add openat_noatime wrapping openat(2) and matching open_noatime

[Rob Browning]

This will be used by a forthcoming file descriptor based drecurse that
doesn't chdir.

Signed-off-by: Rob Browning <r...@defaultvalue.org>
Tested-by: Rob Browning <r...@defaultvalue.org>
---
lib/bup/_helpers.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)

diff --git a/lib/bup/_helpers.c b/lib/bup/_helpers.c
index b7922ec9..a6195ba4 100644
--- a/lib/bup/_helpers.c
+++ b/lib/bup/_helpers.c
@@ -994,6 +994,29 @@ static PyObject *open_noatime(PyObject *self, PyObject *args)
}


+static PyObject *openat_noatime(PyObject *self, PyObject *args)
+{
+ char *name;
+ int fd, flags;
+ if (!PyArg_ParseTuple(args, "iyi", &fd, &name, &flags))
+ return NULL;
+#ifdef O_LARGEFILE
+ flags |= O_LARGEFILE;
+#endif
+#ifdef O_NOATIME
+ const int flags_noatime = flags | O_NOATIME;
+#else
+ const int flags_noatime = flags;
+#endif
+ int ofd = openat(fd, name, flags_noatime);
+ if (ofd < 0 && errno == EPERM) // see _open_noatime comments above
+ ofd = openat(fd, name, flags);
+ if (ofd < 0)
+ return PyErr_SetFromErrno(PyExc_OSError);
+ return Py_BuildValue("i", ofd);
+}
+
+
// Currently the Linux kernel and FUSE disagree over the type for
// FS_IOC_GETFLAGS and FS_IOC_SETFLAGS. The kernel actually uses int,
// but FUSE chose long (matching the declaration in linux/fs.h). So
@@ -1778,6 +1801,8 @@ static PyMethodDef helper_methods[] = {
"Return a random 20-byte string" },
{ "open_noatime", open_noatime, METH_VARARGS,
"open() the given filename for read with O_NOATIME if possible" },
+ { "openat_noatime", openat_noatime, METH_VARARGS,
+ "identical to openat(), but with O_NOATIME if possible" },
#ifdef BUP_HAVE_FILE_ATTRS
{ "get_linux_file_attr", bup_get_linux_file_attr, METH_VARARGS,
"Return the Linux attributes for the given file." },
--
2.47.3