libbtrfsutil: add btrfs_util_is_subvolume() and btrfs_util_subvolume_id()

These are the most trivial helpers in the library and will be used to
implement several of the more involved functions.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/libbtrfsutil/python/subvolume.c b/libbtrfsutil/python/subvolume.c
new file mode 100644
index 00000000..4aab06a5
--- /dev/null
+++ b/libbtrfsutil/python/subvolume.c
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2018 Facebook
+ *
+ * This file is part of libbtrfsutil.
+ *
+ * libbtrfsutil is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * libbtrfsutil is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with libbtrfsutil.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "btrfsutilpy.h"
+
+PyObject *is_subvolume(PyObject *self, PyObject *args, PyObject *kwds)
+{
+	static char *keywords[] = {"path", NULL};
+	struct path_arg path = {.allow_fd = true};
+	enum btrfs_util_error err;
+
+	if (!PyArg_ParseTupleAndKeywords(args, kwds, "O&:is_subvolume",
+					 keywords, &path_converter, &path))
+		return NULL;
+
+	if (path.path)
+		err = btrfs_util_is_subvolume(path.path);
+	else
+		err = btrfs_util_is_subvolume_fd(path.fd);
+	if (err == BTRFS_UTIL_OK) {
+		path_cleanup(&path);
+		Py_RETURN_TRUE;
+	} else if (err == BTRFS_UTIL_ERROR_NOT_BTRFS ||
+		   err == BTRFS_UTIL_ERROR_NOT_SUBVOLUME) {
+		path_cleanup(&path);
+		Py_RETURN_FALSE;
+	} else {
+		SetFromBtrfsUtilErrorWithPath(err, &path);
+		path_cleanup(&path);
+		return NULL;
+	}
+}
+
+PyObject *subvolume_id(PyObject *self, PyObject *args, PyObject *kwds)
+{
+	static char *keywords[] = {"path", NULL};
+	struct path_arg path = {.allow_fd = true};
+	enum btrfs_util_error err;
+	uint64_t id;
+
+	if (!PyArg_ParseTupleAndKeywords(args, kwds, "O&:subvolume_id",
+					 keywords, &path_converter, &path))
+		return NULL;
+
+	if (path.path)
+		err = btrfs_util_subvolume_id(path.path, &id);
+	else
+		err = btrfs_util_subvolume_id_fd(path.fd, &id);
+	if (err) {
+		SetFromBtrfsUtilErrorWithPath(err, &path);
+		path_cleanup(&path);
+		return NULL;
+	}
+
+	path_cleanup(&path);
+	return PyLong_FromUnsignedLongLong(id);
+}