From: Omar Sandoval <osan...@fb.com>
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 <osan...@fb.com>
---
Makefile | 2 +-
libbtrfsutil/btrfsutil.h | 33 ++++++++
libbtrfsutil/python/btrfsutilpy.h | 3 +
libbtrfsutil/python/module.c | 12 +++
libbtrfsutil/python/setup.py | 1 +
libbtrfsutil/python/subvolume.c | 73 ++++++++++++++++
libbtrfsutil/python/tests/__init__.py | 66 +++++++++++++++
libbtrfsutil/python/tests/test_subvolume.py | 57 +++++++++++++
libbtrfsutil/subvolume.c | 127 ++++++++++++++++++++++++++++
9 files changed, 373 insertions(+), 1 deletion(-)
create mode 100644 libbtrfsutil/python/subvolume.c
create mode 100644 libbtrfsutil/python/tests/test_subvolume.py
create mode 100644 libbtrfsutil/subvolume.c
diff --git a/Makefile b/Makefile
index 95ee9678..58b3eca4 100644
--- a/Makefile
+++ b/Makefile
@@ -135,7 +135,7 @@ libbtrfsutil_major := $(shell sed -rn 's/^\#define
BTRFS_UTIL_VERSION_MAJOR ([0-
libbtrfsutil_minor := $(shell sed -rn 's/^\#define BTRFS_UTIL_VERSION_MINOR
([0-9])+$$/\1/p' libbtrfsutil/btrfsutil.h)
libbtrfsutil_patch := $(shell sed -rn 's/^\#define BTRFS_UTIL_VERSION_PATCH
([0-9])+$$/\1/p' libbtrfsutil/btrfsutil.h)
libbtrfsutil_version :=
$(libbtrfsutil_major).$(libbtrfsutil_minor).$(libbtrfsutil_patch)
-libbtrfsutil_objects = libbtrfsutil/errors.o
+libbtrfsutil_objects = libbtrfsutil/errors.o libbtrfsutil/subvolume.o
convert_objects = convert/main.o convert/common.o convert/source-fs.o \
convert/source-ext2.o convert/source-reiserfs.o
mkfs_objects = mkfs/main.o mkfs/common.o mkfs/rootdir.o
diff --git a/libbtrfsutil/btrfsutil.h b/libbtrfsutil/btrfsutil.h
index 867418f2..ca36f695 100644
--- a/libbtrfsutil/btrfsutil.h
+++ b/libbtrfsutil/btrfsutil.h
@@ -20,6 +20,8 @@
#ifndef BTRFS_UTIL_H
#define BTRFS_UTIL_H
+#include <stdint.h>
+
#define BTRFS_UTIL_VERSION_MAJOR 1
#define BTRFS_UTIL_VERSION_MINOR 0
#define BTRFS_UTIL_VERSION_PATCH 0
@@ -69,6 +71,37 @@ enum btrfs_util_error {
*/
const char *btrfs_util_strerror(enum btrfs_util_error err);
+/**
+ * btrfs_util_is_subvolume() - Return whether a given path is a Btrfs
subvolume.
+ * @path: Path to check.
+ *
+ * Return: %BTRFS_UTIL_OK if @path is a Btrfs subvolume,
+ * %BTRFS_UTIL_ERROR_NOT_BTRFS if @path is not on a Btrfs filesystem,
+ * %BTRFS_UTIL_ERROR_NOT_SUBVOLUME if @path is not a subvolume, non-zero error
+ * code on any other failure.
+ */
+enum btrfs_util_error btrfs_util_is_subvolume(const char *path);
+
+/**
+ * btrfs_util_is_subvolume_fd() - See btrfs_util_is_subvolume().
+ */
+enum btrfs_util_error btrfs_util_is_subvolume_fd(int fd);
+
+/**
+ * btrfs_util_subvolume_id() - Get the ID of the subvolume containing a path.
+ * @path: Path on a Btrfs filesystem.
+ * @id_ret: Returned subvolume ID.
+ *
+ * Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
+ */
+enum btrfs_util_error btrfs_util_subvolume_id(const char *path,
+ uint64_t *id_ret);
+
+/**
+ * btrfs_util_subvolume_id_fd() - See btrfs_util_subvolume_id().
+ */
+enum btrfs_util_error btrfs_util_subvolume_id_fd(int fd, uint64_t *id_ret);
+
#ifdef __cplusplus
}
#endif
diff --git a/libbtrfsutil/python/btrfsutilpy.h
b/libbtrfsutil/python/btrfsutilpy.h
index 6d82f7e1..9a04fda7 100644
--- a/libbtrfsutil/python/btrfsutilpy.h
+++ b/libbtrfsutil/python/btrfsutilpy.h
@@ -52,6 +52,9 @@ void SetFromBtrfsUtilErrorWithPaths(enum btrfs_util_error err,
struct path_arg *path1,
struct path_arg *path2);
+PyObject *is_subvolume(PyObject *self, PyObject *args, PyObject *kwds);
+PyObject *subvolume_id(PyObject *self, PyObject *args, PyObject *kwds);
+
void add_module_constants(PyObject *m);
#endif /* BTRFSUTILPY_H */
diff --git a/libbtrfsutil/python/module.c b/libbtrfsutil/python/module.c
index d7398808..d492cbc7 100644
--- a/libbtrfsutil/python/module.c
+++ b/libbtrfsutil/python/module.c
@@ -132,6 +132,18 @@ void path_cleanup(struct path_arg *path)
}
static PyMethodDef btrfsutil_methods[] = {
+ {"is_subvolume", (PyCFunction)is_subvolume,
+ METH_VARARGS | METH_KEYWORDS,
+ "is_subvolume(path) -> bool\n\n"
+ "Get whether a file is a subvolume.\n\n"
+ "Arguments:\n"
+ "path -- string, bytes, path-like object, or open file descriptor"},
+ {"subvolume_id", (PyCFunction)subvolume_id,
+ METH_VARARGS | METH_KEYWORDS,
+ "subvolume_id(path) -> int\n\n"
+ "Get the ID of the subvolume containing a file.\n\n"
+ "Arguments:\n"
+ "path -- string, bytes, path-like object, or open file descriptor"},
{},
};
diff --git a/libbtrfsutil/python/setup.py b/libbtrfsutil/python/setup.py
index cd8a6048..57249829 100755
--- a/libbtrfsutil/python/setup.py
+++ b/libbtrfsutil/python/setup.py
@@ -91,6 +91,7 @@ module = Extension(
'constants.c',
'error.c',
'module.c',
+ 'subvolume.c',
],
include_dirs=['..'],
library_dirs=['../..'],
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);
+}
diff --git a/libbtrfsutil/python/tests/__init__.py
b/libbtrfsutil/python/tests/__init__.py
index e69de29b..d2c6ff28 100644
--- a/libbtrfsutil/python/tests/__init__.py
+++ b/libbtrfsutil/python/tests/__init__.py
@@ -0,0 +1,66 @@
+# 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/>.
+
+import os
+from pathlib import PurePath
+import subprocess
+import tempfile
+import unittest
+
+
+HAVE_PATH_LIKE = hasattr(PurePath, '__fspath__')
+
+
+@unittest.skipIf(os.geteuid() != 0, 'must be run as root')
+class BtrfsTestCase(unittest.TestCase):
+ def setUp(self):
+ self.mountpoint = tempfile.mkdtemp()
+ try:
+ with tempfile.NamedTemporaryFile(delete=False) as f:
+ os.truncate(f.fileno(), 1024 * 1024 * 1024)
+ self.image = f.name
+ except Exception as e:
+ os.rmdir(self.mountpoint)
+ raise e
+
+ try:
+ subprocess.check_call(['mkfs.btrfs', '-q', self.image])
+ subprocess.check_call(['mount', '-o', 'loop', '--', self.image,
self.mountpoint])
+ except Exception as e:
+ os.remove(self.image)
+ os.rmdir(self.mountpoint)
+ raise e
+
+ def tearDown(self):
+ try:
+ subprocess.check_call(['umount', self.mountpoint])
+ finally:
+ os.remove(self.image)
+ os.rmdir(self.mountpoint)
+
+ @staticmethod
+ def path_or_fd(path, open_flags=os.O_RDONLY):
+ yield path
+ yield path.encode()
+ if HAVE_PATH_LIKE:
+ yield PurePath(path)
+ fd = os.open(path, open_flags)
+ try:
+ yield fd
+ finally:
+ os.close(fd)
+
diff --git a/libbtrfsutil/python/tests/test_subvolume.py
b/libbtrfsutil/python/tests/test_subvolume.py
new file mode 100644
index 00000000..44b1d7f0
--- /dev/null
+++ b/libbtrfsutil/python/tests/test_subvolume.py
@@ -0,0 +1,57 @@
+# 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/>.
+
+import fcntl
+import errno
+import os
+import os.path
+from pathlib import PurePath
+import traceback
+
+import btrfsutil
+from tests import BtrfsTestCase
+
+
+class TestSubvolume(BtrfsTestCase):
+ def test_is_subvolume(self):
+ dir = os.path.join(self.mountpoint, 'foo')
+ os.mkdir(dir)
+
+ for arg in self.path_or_fd(self.mountpoint):
+ with self.subTest(type=type(arg)):
+ self.assertTrue(btrfsutil.is_subvolume(arg))
+ for arg in self.path_or_fd(dir):
+ with self.subTest(type=type(arg)):
+ self.assertFalse(btrfsutil.is_subvolume(arg))
+
+ with self.assertRaises(btrfsutil.BtrfsUtilError) as e:
+ btrfsutil.is_subvolume(os.path.join(self.mountpoint, 'bar'))
+ # This is a bit of an implementation detail, but really this is testing
+ # that the exception is initialized correctly.
+ self.assertEqual(e.exception.btrfsutilerror,
btrfsutil.ERROR_STATFS_FAILED)
+ self.assertEqual(e.exception.errno, errno.ENOENT)
+
+ def test_subvolume_id(self):
+ dir = os.path.join(self.mountpoint, 'foo')
+ os.mkdir(dir)
+
+ for arg in self.path_or_fd(self.mountpoint):
+ with self.subTest(type=type(arg)):
+ self.assertEqual(btrfsutil.subvolume_id(arg), 5)
+ for arg in self.path_or_fd(dir):
+ with self.subTest(type=type(arg)):
+ self.assertEqual(btrfsutil.subvolume_id(arg), 5)
diff --git a/libbtrfsutil/subvolume.c b/libbtrfsutil/subvolume.c
new file mode 100644
index 00000000..04988c14
--- /dev/null
+++ b/libbtrfsutil/subvolume.c
@@ -0,0 +1,127 @@
+/*
+ * 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 <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/vfs.h>
+#include <linux/btrfs.h>
+#include <linux/btrfs_tree.h>
+#include <linux/magic.h>
+
+#include "btrfsutil_internal.h"
+
+/*
+ * This intentionally duplicates btrfs_util_is_subvolume_fd() instead of
opening
+ * a file descriptor and calling it, because fstat() and fstatfs() don't accept
+ * file descriptors opened with O_PATH on old kernels (before v3.6 and before
+ * v3.12, respectively), but stat() and statfs() can be called on a path that
+ * the user doesn't have read or write permissions to.
+ */
+PUBLIC enum btrfs_util_error btrfs_util_is_subvolume(const char *path)
+{
+ struct statfs sfs;
+ struct stat st;
+ int ret;
+
+ ret = statfs(path, &sfs);
+ if (ret == -1)
+ return BTRFS_UTIL_ERROR_STATFS_FAILED;
+
+ if (sfs.f_type != BTRFS_SUPER_MAGIC) {
+ errno = EINVAL;
+ return BTRFS_UTIL_ERROR_NOT_BTRFS;
+ }
+
+ ret = stat(path, &st);
+ if (ret == -1)
+ return BTRFS_UTIL_ERROR_STAT_FAILED;
+
+ if (st.st_ino != BTRFS_FIRST_FREE_OBJECTID || !S_ISDIR(st.st_mode)) {
+ errno = EINVAL;
+ return BTRFS_UTIL_ERROR_NOT_SUBVOLUME;
+ }
+
+ return BTRFS_UTIL_OK;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_is_subvolume_fd(int fd)
+{
+ struct statfs sfs;
+ struct stat st;
+ int ret;
+
+ ret = fstatfs(fd, &sfs);
+ if (ret == -1)
+ return BTRFS_UTIL_ERROR_STATFS_FAILED;
+
+ if (sfs.f_type != BTRFS_SUPER_MAGIC) {
+ errno = EINVAL;
+ return BTRFS_UTIL_ERROR_NOT_BTRFS;
+ }
+
+ ret = fstat(fd, &st);
+ if (ret == -1)
+ return BTRFS_UTIL_ERROR_STAT_FAILED;
+
+ if (st.st_ino != BTRFS_FIRST_FREE_OBJECTID || !S_ISDIR(st.st_mode)) {
+ errno = EINVAL;
+ return BTRFS_UTIL_ERROR_NOT_SUBVOLUME;
+ }
+
+ return BTRFS_UTIL_OK;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_subvolume_id(const char *path,
+ uint64_t *id_ret)
+{
+ enum btrfs_util_error err;
+ int fd;
+
+ fd = open(path, O_RDONLY);
+ if (fd == -1)
+ return BTRFS_UTIL_ERROR_OPEN_FAILED;
+
+ err = btrfs_util_subvolume_id_fd(fd, id_ret);
+ SAVE_ERRNO_AND_CLOSE(fd);
+ return err;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_subvolume_id_fd(int fd,
+ uint64_t *id_ret)
+{
+ struct btrfs_ioctl_ino_lookup_args args = {
+ .treeid = 0,
+ .objectid = BTRFS_FIRST_FREE_OBJECTID,
+ };
+ int ret;
+
+ ret = ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args);
+ if (ret == -1) {
+ close(fd);
+ return BTRFS_UTIL_ERROR_INO_LOOKUP_FAILED;
+ }
+
+ *id_ret = args.treeid;
+
+ return BTRFS_UTIL_OK;
+}
--
2.16.1
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