| Message ID | ec89f2b55edb450ce4fcbe1485ae8f57ed51187c.1516991902.git.osandov@fb.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 26.01.2018 20:40, Omar Sandoval wrote: > From: Omar Sandoval <osandov@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 <osandov@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 | 137 ++++++++++++++++++++++++++++ > 9 files changed, 383 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 02b03e81..48a558a9 100644 > --- a/Makefile > +++ b/Makefile > @@ -123,7 +123,7 @@ libbtrfs_headers = send-stream.h send-utils.h send.h kernel-lib/rbtree.h btrfs-l > kernel-lib/radix-tree.h kernel-lib/sizes.h kernel-lib/raid56.h \ > extent-cache.h extent_io.h ioctl.h ctree.h btrfsck.h version.h > libbtrfsutil_version := 0.1 > -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 > diff --git a/libbtrfsutil/btrfsutil.h b/libbtrfsutil/btrfsutil.h > index fe1091ca..dff6599d 100644 > --- a/libbtrfsutil/btrfsutil.h > +++ b/libbtrfsutil/btrfsutil.h > @@ -20,6 +20,8 @@ > #ifndef BTRFS_UTIL_H > #define BTRFS_UTIL_H > > +#include <stdint.h> > + > #ifdef __cplusplus > extern "C" { > #endif > @@ -65,6 +67,37 @@ 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_f_is_subvolume() - See btrfs_util_is_subvolume(). > + */ > +enum btrfs_util_error btrfs_util_f_is_subvolume(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_f_subvolume_id() - See btrfs_util_subvolume_id(). > + */ > +enum btrfs_util_error btrfs_util_f_subvolume_id(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 3dc778ab..be973a34 100755 > --- a/libbtrfsutil/python/setup.py > +++ b/libbtrfsutil/python/setup.py > @@ -79,6 +79,7 @@ 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..538bf324 > --- /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_f_is_subvolume(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_f_subvolume_id(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..37d5d388 > --- /dev/null > +++ b/libbtrfsutil/subvolume.c > @@ -0,0 +1,137 @@ > +/* > + * 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.h" > + > +#define SAVE_ERRNO_AND_CLOSE(fd) { \ > + int saved_errno = errno; \ > + \ > + close(fd); \ > + errno = saved_errno; \ > +} > + > +/* > + * This intentionally duplicates btrfs_util_f_is_subvolume() 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. > + */ > +__attribute__((visibility("default"))) Why do we need to explicitly set the attribute visibility to default, isn't it implicitly default already? > +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; > +} > + > +__attribute__((visibility("default"))) > +enum btrfs_util_error btrfs_util_f_is_subvolume(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; > +} > + > +__attribute__((visibility("default"))) > +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_f_subvolume_id(fd, id_ret); > + SAVE_ERRNO_AND_CLOSE(fd); > + return err; > +} > + > +__attribute__((visibility("default"))) > +enum btrfs_util_error btrfs_util_f_subvolume_id(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; > +} > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Jan 29, 2018 at 12:24:26PM +0200, Nikolay Borisov wrote: > On 26.01.2018 20:40, Omar Sandoval wrote: [snip] > > +/* > > + * This intentionally duplicates btrfs_util_f_is_subvolume() 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. > > + */ > > +__attribute__((visibility("default"))) > > Why do we need to explicitly set the attribute visibility to default, > isn't it implicitly default already? Ah, I forgot to add -fvisibility=hidden to the build rule when I ported this to the btrfs-progs Makefile, that's why that's there. I'll add -fvisibility=hidden to the Makefile. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 29.01.2018 23:43, Omar Sandoval wrote: > On Mon, Jan 29, 2018 at 12:24:26PM +0200, Nikolay Borisov wrote: >> On 26.01.2018 20:40, Omar Sandoval wrote: > [snip] >>> +/* >>> + * This intentionally duplicates btrfs_util_f_is_subvolume() 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. >>> + */ >>> +__attribute__((visibility("default"))) >> >> Why do we need to explicitly set the attribute visibility to default, >> isn't it implicitly default already? > > Ah, I forgot to add -fvisibility=hidden to the build rule when I ported > this to the btrfs-progs Makefile, that's why that's there. I'll add > -fvisibility=hidden to the Makefile. Right, it could be a good idea to hide the visibility attribute behind an eloquent macro i.e. (PUBLIC|LIBRARY)_FUNC or some such. > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jan 30, 2018 at 08:54:08AM +0200, Nikolay Borisov wrote: > > > On 29.01.2018 23:43, Omar Sandoval wrote: > > On Mon, Jan 29, 2018 at 12:24:26PM +0200, Nikolay Borisov wrote: > >> On 26.01.2018 20:40, Omar Sandoval wrote: > > [snip] > >>> +/* > >>> + * This intentionally duplicates btrfs_util_f_is_subvolume() 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. > >>> + */ > >>> +__attribute__((visibility("default"))) > >> > >> Why do we need to explicitly set the attribute visibility to default, > >> isn't it implicitly default already? > > > > Ah, I forgot to add -fvisibility=hidden to the build rule when I ported > > this to the btrfs-progs Makefile, that's why that's there. I'll add > > -fvisibility=hidden to the Makefile. > > Right, it could be a good idea to hide the visibility attribute behind > an eloquent macro i.e. (PUBLIC|LIBRARY)_FUNC or some such. Macro would be better (but is not needed for the initial version). Alternatively the library .sym file can externally track the exported symbols and also track versioning. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Feb 01, 2018 at 05:28:28PM +0100, David Sterba wrote: > On Tue, Jan 30, 2018 at 08:54:08AM +0200, Nikolay Borisov wrote: > > > > > > On 29.01.2018 23:43, Omar Sandoval wrote: > > > On Mon, Jan 29, 2018 at 12:24:26PM +0200, Nikolay Borisov wrote: > > >> On 26.01.2018 20:40, Omar Sandoval wrote: > > > [snip] > > >>> +/* > > >>> + * This intentionally duplicates btrfs_util_f_is_subvolume() 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. > > >>> + */ > > >>> +__attribute__((visibility("default"))) > > >> > > >> Why do we need to explicitly set the attribute visibility to default, > > >> isn't it implicitly default already? > > > > > > Ah, I forgot to add -fvisibility=hidden to the build rule when I ported > > > this to the btrfs-progs Makefile, that's why that's there. I'll add > > > -fvisibility=hidden to the Makefile. > > > > Right, it could be a good idea to hide the visibility attribute behind > > an eloquent macro i.e. (PUBLIC|LIBRARY)_FUNC or some such. > > Macro would be better (but is not needed for the initial version). > > Alternatively the library .sym file can externally track the exported > symbols and also track versioning. I'll add a macro for this, thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Makefile b/Makefile index 02b03e81..48a558a9 100644 --- a/Makefile +++ b/Makefile @@ -123,7 +123,7 @@ libbtrfs_headers = send-stream.h send-utils.h send.h kernel-lib/rbtree.h btrfs-l kernel-lib/radix-tree.h kernel-lib/sizes.h kernel-lib/raid56.h \ extent-cache.h extent_io.h ioctl.h ctree.h btrfsck.h version.h libbtrfsutil_version := 0.1 -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 diff --git a/libbtrfsutil/btrfsutil.h b/libbtrfsutil/btrfsutil.h index fe1091ca..dff6599d 100644 --- a/libbtrfsutil/btrfsutil.h +++ b/libbtrfsutil/btrfsutil.h @@ -20,6 +20,8 @@ #ifndef BTRFS_UTIL_H #define BTRFS_UTIL_H +#include <stdint.h> + #ifdef __cplusplus extern "C" { #endif @@ -65,6 +67,37 @@ 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_f_is_subvolume() - See btrfs_util_is_subvolume(). + */ +enum btrfs_util_error btrfs_util_f_is_subvolume(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_f_subvolume_id() - See btrfs_util_subvolume_id(). + */ +enum btrfs_util_error btrfs_util_f_subvolume_id(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 3dc778ab..be973a34 100755 --- a/libbtrfsutil/python/setup.py +++ b/libbtrfsutil/python/setup.py @@ -79,6 +79,7 @@ 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..538bf324 --- /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_f_is_subvolume(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_f_subvolume_id(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..37d5d388 --- /dev/null +++ b/libbtrfsutil/subvolume.c @@ -0,0 +1,137 @@ +/* + * 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.h" + +#define SAVE_ERRNO_AND_CLOSE(fd) { \ + int saved_errno = errno; \ + \ + close(fd); \ + errno = saved_errno; \ +} + +/* + * This intentionally duplicates btrfs_util_f_is_subvolume() 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. + */ +__attribute__((visibility("default"))) +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; +} + +__attribute__((visibility("default"))) +enum btrfs_util_error btrfs_util_f_is_subvolume(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; +} + +__attribute__((visibility("default"))) +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_f_subvolume_id(fd, id_ret); + SAVE_ERRNO_AND_CLOSE(fd); + return err; +} + +__attribute__((visibility("default"))) +enum btrfs_util_error btrfs_util_f_subvolume_id(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; +}