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authorOmar Sandoval <osandov@fb.com>2018-11-13 23:47:03 -0800
committerDavid Sterba <dsterba@suse.com>2018-11-26 16:45:34 +0100
commit2a74c0e4ee9a4a66deadc99045e69e68f2c33136 (patch)
treea709c7e0aa5b1000725283da03861e4d057a8564 /libbtrfsutil
parentbfe2dc379662bd2aba40db9fe9185a57dae0c4a9 (diff)
libbtrfsutil: relax the privileges of subvolume iterator
We can use the new BTRFS_IOC_GET_SUBVOL_ROOTREF and BTRFS_IOC_INO_LOOKUP_USER ioctls to allow non-root users to list subvolumes. This is based on a patch from Misono Tomohiro but takes a different approach (mainly, this approach is more similar to the existing tree search approach). Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'libbtrfsutil')
-rw-r--r--libbtrfsutil/btrfsutil.h15
-rw-r--r--libbtrfsutil/errors.c6
-rw-r--r--libbtrfsutil/python/tests/test_subvolume.py180
-rw-r--r--libbtrfsutil/subvolume.c354
4 files changed, 450 insertions, 105 deletions
diff --git a/libbtrfsutil/btrfsutil.h b/libbtrfsutil/btrfsutil.h
index c192500..d88c39e 100644
--- a/libbtrfsutil/btrfsutil.h
+++ b/libbtrfsutil/btrfsutil.h
@@ -64,6 +64,9 @@ enum btrfs_util_error {
BTRFS_UTIL_ERROR_START_SYNC_FAILED,
BTRFS_UTIL_ERROR_WAIT_SYNC_FAILED,
BTRFS_UTIL_ERROR_GET_SUBVOL_INFO_FAILED,
+ BTRFS_UTIL_ERROR_GET_SUBVOL_ROOTREF_FAILED,
+ BTRFS_UTIL_ERROR_INO_LOOKUP_USER_FAILED,
+ BTRFS_UTIL_ERROR_FS_INFO_FAILED,
};
/**
@@ -507,6 +510,12 @@ struct btrfs_util_subvolume_iterator;
* @flags: Bitmask of BTRFS_UTIL_SUBVOLUME_ITERATOR_* flags.
* @ret: Returned iterator.
*
+ * Subvolume iterators require appropriate privilege (CAP_SYS_ADMIN) unless @top
+ * is zero and the kernel supports BTRFS_IOC_GET_SUBVOL_ROOTREF and
+ * BTRFS_IOC_INO_LOOKUP_USER (kernel >= 4.18). In this case, subvolumes which
+ * cannot be accessed (e.g., due to permissions or other mounts) will be
+ * skipped.
+ *
* The returned iterator must be freed with
* btrfs_util_destroy_subvolume_iterator().
*
@@ -555,7 +564,8 @@ int btrfs_util_subvolume_iterator_fd(const struct btrfs_util_subvolume_iterator
* Must be freed with free().
* @id_ret: Returned subvolume ID. May be %NULL.
*
- * This requires appropriate privilege (CAP_SYS_ADMIN).
+ * This requires appropriate privilege (CAP_SYS_ADMIN) for kernels < 4.18. See
+ * btrfs_util_create_subvolume_iterator().
*
* Return: %BTRFS_UTIL_OK on success, %BTRFS_UTIL_ERROR_STOP_ITERATION if there
* are no more subvolumes, non-zero error code on failure.
@@ -574,7 +584,8 @@ enum btrfs_util_error btrfs_util_subvolume_iterator_next(struct btrfs_util_subvo
* This convenience function basically combines
* btrfs_util_subvolume_iterator_next() and btrfs_util_subvolume_info().
*
- * This requires appropriate privilege (CAP_SYS_ADMIN).
+ * This requires appropriate privilege (CAP_SYS_ADMIN) for kernels < 4.18. See
+ * btrfs_util_create_subvolume_iterator().
*
* Return: See btrfs_util_subvolume_iterator_next().
*/
diff --git a/libbtrfsutil/errors.c b/libbtrfsutil/errors.c
index cf968b0..d39b38d 100644
--- a/libbtrfsutil/errors.c
+++ b/libbtrfsutil/errors.c
@@ -47,6 +47,12 @@ static const char * const error_messages[] = {
[BTRFS_UTIL_ERROR_WAIT_SYNC_FAILED] = "Could not wait for filesystem sync",
[BTRFS_UTIL_ERROR_GET_SUBVOL_INFO_FAILED] =
"Could not get subvolume information with BTRFS_IOC_GET_SUBVOL_INFO",
+ [BTRFS_UTIL_ERROR_GET_SUBVOL_ROOTREF_FAILED] =
+ "Could not get rootref information with BTRFS_IOC_GET_SUBVOL_ROOTREF",
+ [BTRFS_UTIL_ERROR_INO_LOOKUP_USER_FAILED] =
+ "Could not resolve subvolume path with BTRFS_IOC_INO_LOOKUP_USER",
+ [BTRFS_UTIL_ERROR_FS_INFO_FAILED] =
+ "Could not get filesystem information",
};
PUBLIC const char *btrfs_util_strerror(enum btrfs_util_error err)
diff --git a/libbtrfsutil/python/tests/test_subvolume.py b/libbtrfsutil/python/tests/test_subvolume.py
index 55ebf34..99ec97b 100644
--- a/libbtrfsutil/python/tests/test_subvolume.py
+++ b/libbtrfsutil/python/tests/test_subvolume.py
@@ -20,6 +20,7 @@ import errno
import os
import os.path
from pathlib import PurePath
+import subprocess
import traceback
import btrfsutil
@@ -27,6 +28,8 @@ from tests import (
BtrfsTestCase,
drop_privs,
HAVE_PATH_LIKE,
+ NOBODY_UID,
+ regain_privs,
skipUnlessHaveNobody,
)
@@ -354,69 +357,136 @@ class TestSubvolume(BtrfsTestCase):
with self.subTest(type=type(arg)):
self.assertEqual(btrfsutil.deleted_subvolumes(arg), [256])
- def test_subvolume_iterator(self):
- pwd = os.getcwd()
- try:
- os.chdir(self.mountpoint)
- btrfsutil.create_subvolume('foo')
-
- with btrfsutil.SubvolumeIterator('.', info=True) as it:
- path, subvol = next(it)
- self.assertEqual(path, 'foo')
- self.assertIsInstance(subvol, btrfsutil.SubvolumeInfo)
- self.assertEqual(subvol.id, 256)
- self.assertEqual(subvol.parent_id, 5)
- self.assertRaises(StopIteration, next, it)
-
- btrfsutil.create_subvolume('foo/bar')
- btrfsutil.create_subvolume('foo/bar/baz')
-
- subvols = [
- ('foo', 256),
- ('foo/bar', 257),
- ('foo/bar/baz', 258),
- ]
-
- for arg in self.path_or_fd('.'):
- with self.subTest(type=type(arg)), btrfsutil.SubvolumeIterator(arg) as it:
- self.assertEqual(list(it), subvols)
- with btrfsutil.SubvolumeIterator('.', top=0) as it:
+ def _test_subvolume_iterator(self):
+ btrfsutil.create_subvolume('foo')
+
+ with btrfsutil.SubvolumeIterator('.', info=True) as it:
+ path, subvol = next(it)
+ self.assertEqual(path, 'foo')
+ self.assertIsInstance(subvol, btrfsutil.SubvolumeInfo)
+ self.assertEqual(subvol.id, 256)
+ self.assertEqual(subvol.parent_id, 5)
+ self.assertRaises(StopIteration, next, it)
+
+ btrfsutil.create_subvolume('foo/bar')
+ btrfsutil.create_subvolume('foo/bar/baz')
+
+ subvols = [
+ ('foo', 256),
+ ('foo/bar', 257),
+ ('foo/bar/baz', 258),
+ ]
+
+ for arg in self.path_or_fd('.'):
+ with self.subTest(type=type(arg)), btrfsutil.SubvolumeIterator(arg) as it:
self.assertEqual(list(it), subvols)
+ with btrfsutil.SubvolumeIterator('.', top=0) as it:
+ self.assertEqual(list(it), subvols)
+ if os.geteuid() == 0:
with btrfsutil.SubvolumeIterator('foo', top=5) as it:
self.assertEqual(list(it), subvols)
- with btrfsutil.SubvolumeIterator('.', post_order=True) as it:
- self.assertEqual(list(it),
- [('foo/bar/baz', 258),
- ('foo/bar', 257),
- ('foo', 256)])
+ with btrfsutil.SubvolumeIterator('.', post_order=True) as it:
+ self.assertEqual(list(it),
+ [('foo/bar/baz', 258),
+ ('foo/bar', 257),
+ ('foo', 256)])
- subvols = [
- ('bar', 257),
- ('bar/baz', 258),
- ]
+ subvols = [
+ ('bar', 257),
+ ('bar/baz', 258),
+ ]
+ if os.geteuid() == 0:
with btrfsutil.SubvolumeIterator('.', top=256) as it:
self.assertEqual(list(it), subvols)
- with btrfsutil.SubvolumeIterator('foo') as it:
- self.assertEqual(list(it), subvols)
- with btrfsutil.SubvolumeIterator('foo', top=0) as it:
- self.assertEqual(list(it), subvols)
+ with btrfsutil.SubvolumeIterator('foo') as it:
+ self.assertEqual(list(it), subvols)
+ with btrfsutil.SubvolumeIterator('foo', top=0) as it:
+ self.assertEqual(list(it), subvols)
+
+ os.rename('foo/bar/baz', 'baz')
+ os.mkdir('dir')
+ btrfsutil.create_subvolume('dir/qux')
+ os.mkdir('dir/qux/dir2')
+ btrfsutil.create_subvolume('dir/qux/dir2/quux')
+
+ subvols = [
+ ('baz', 258),
+ ('dir/qux', 259),
+ ('dir/qux/dir2/quux', 260),
+ ('foo', 256),
+ ('foo/bar', 257),
+ ]
+
+ # Test various corner cases of the unprivileged implementation
+ # where we can't access the subvolume.
+ if os.geteuid() != 0:
+ with regain_privs():
+ # We don't have permission to traverse the path.
+ os.mkdir('directory_perms', 0o700)
+ btrfsutil.create_subvolume('directory_perms/subvol')
+
+ # We don't have permission to resolve the subvolume path.
+ os.mkdir('subvol_perms', 0o755)
+ btrfsutil.create_subvolume('subvol_perms/subvol')
+ os.chmod('subvol_perms/subvol', 0o700)
+
+ # The path doesn't exist.
+ os.mkdir('enoent', 0o755)
+ btrfsutil.create_subvolume('enoent/subvol')
+ subprocess.check_call(['mount', '-t', 'tmpfs', 'tmpfs', 'enoent'])
+
+ # The path exists but it's not a subvolume.
+ os.mkdir('notsubvol', 0o755)
+ btrfsutil.create_subvolume('notsubvol/subvol')
+ subprocess.check_call(['mount', '-t', 'tmpfs', 'tmpfs', 'notsubvol'])
+ os.mkdir('notsubvol/subvol')
+
+ # The path exists and is a subvolume, but on a different
+ # filesystem.
+ os.mkdir('wrongfs', 0o755)
+ btrfsutil.create_subvolume('wrongfs/subvol')
+ other_mountpoint, _ = self.mount_btrfs()
+ subprocess.check_call(['mount', '--bind', '--',
+ other_mountpoint, 'wrongfs/subvol'])
+
+ # The path exists and is a subvolume on the same
+ # filesystem, but not the right one.
+ os.mkdir('wrongsubvol', 0o755)
+ btrfsutil.create_subvolume('wrongsubvol/subvol')
+ subprocess.check_call(['mount', '--bind', 'baz', 'wrongsubvol/subvol'])
+
+
+ with btrfsutil.SubvolumeIterator('.') as it:
+ self.assertEqual(sorted(it), subvols)
+ with btrfsutil.SubvolumeIterator('.', post_order=True) as it:
+ self.assertEqual(sorted(it), subvols)
+
+ with btrfsutil.SubvolumeIterator('.') as it:
+ self.assertGreaterEqual(it.fileno(), 0)
+ it.close()
+ with self.assertRaises(ValueError):
+ next(iter(it))
+ with self.assertRaises(ValueError):
+ it.fileno()
+ it.close()
- os.rename('foo/bar/baz', 'baz')
- with btrfsutil.SubvolumeIterator('.') as it:
- self.assertEqual(sorted(it),
- [('baz', 258),
- ('foo', 256),
- ('foo/bar', 257)])
-
- with btrfsutil.SubvolumeIterator('.') as it:
- self.assertGreaterEqual(it.fileno(), 0)
- it.close()
- with self.assertRaises(ValueError):
- next(iter(it))
- with self.assertRaises(ValueError):
- it.fileno()
- it.close()
+ def test_subvolume_iterator(self):
+ pwd = os.getcwd()
+ try:
+ os.chdir(self.mountpoint)
+ self._test_subvolume_iterator()
+ finally:
+ os.chdir(pwd)
+
+ @skipUnlessHaveNobody
+ def test_subvolume_iterator_unprivileged(self):
+ os.chown(self.mountpoint, NOBODY_UID, -1)
+ pwd = os.getcwd()
+ try:
+ os.chdir(self.mountpoint)
+ with drop_privs():
+ self._test_subvolume_iterator()
finally:
os.chdir(pwd)
diff --git a/libbtrfsutil/subvolume.c b/libbtrfsutil/subvolume.c
index 69654db..60ab9f9 100644
--- a/libbtrfsutil/subvolume.c
+++ b/libbtrfsutil/subvolume.c
@@ -749,13 +749,28 @@ PUBLIC enum btrfs_util_error btrfs_util_create_subvolume_fd(int parent_fd,
#define BTRFS_UTIL_SUBVOLUME_ITERATOR_CLOSE_FD (1 << 30)
struct search_stack_entry {
- struct btrfs_ioctl_search_args search;
- size_t items_pos, buf_off;
+ union {
+ /* Used for subvolume_iterator_next_tree_search(). */
+ struct {
+ struct btrfs_ioctl_search_args search;
+ size_t buf_off;
+ };
+ /* Used for subvolume_iterator_next_unprivileged(). */
+ struct {
+ uint64_t id;
+ struct btrfs_ioctl_get_subvol_rootref_args rootref_args;
+ };
+ };
+ /* Used for both. */
+ size_t items_pos;
size_t path_len;
};
struct btrfs_util_subvolume_iterator {
+ bool use_tree_search;
int fd;
+ /* cur_fd is only used for subvolume_iterator_next_unprivileged(). */
+ int cur_fd;
int flags;
struct search_stack_entry *search_stack;
@@ -766,6 +781,58 @@ struct btrfs_util_subvolume_iterator {
size_t cur_path_capacity;
};
+static struct search_stack_entry *top_search_stack_entry(struct btrfs_util_subvolume_iterator *iter)
+{
+ return &iter->search_stack[iter->search_stack_len - 1];
+}
+
+/*
+ * Check that a path that we opened is the subvolume which we expect. It may not
+ * be if there is another filesystem mounted over a parent directory or the
+ * subvolume itself.
+ */
+static enum btrfs_util_error check_expected_subvolume(int fd, int parent_fd,
+ uint64_t tree_id)
+{
+ struct btrfs_ioctl_fs_info_args parent_fs_info, fs_info;
+ enum btrfs_util_error err;
+ uint64_t id;
+ int ret;
+
+ /* Make sure it's a subvolume. */
+ err = btrfs_util_is_subvolume_fd(fd);
+ if (err == BTRFS_UTIL_ERROR_NOT_BTRFS ||
+ err == BTRFS_UTIL_ERROR_NOT_SUBVOLUME) {
+ errno = ENOENT;
+ return BTRFS_UTIL_ERROR_SUBVOLUME_NOT_FOUND;
+ } else if (err) {
+ return err;
+ }
+
+ /* Make sure it's on the same filesystem. */
+ ret = ioctl(parent_fd, BTRFS_IOC_FS_INFO, &parent_fs_info);
+ if (ret == -1)
+ return BTRFS_UTIL_ERROR_FS_INFO_FAILED;
+ ret = ioctl(fd, BTRFS_IOC_FS_INFO, &fs_info);
+ if (ret == -1)
+ return BTRFS_UTIL_ERROR_FS_INFO_FAILED;
+ if (memcmp(parent_fs_info.fsid, fs_info.fsid, sizeof(fs_info.fsid)) != 0) {
+ errno = ENOENT;
+ return BTRFS_UTIL_ERROR_SUBVOLUME_NOT_FOUND;
+ }
+
+ /* Make sure it's the subvolume that we expected. */
+ err = btrfs_util_subvolume_id_fd(fd, &id);
+ if (err)
+ return err;
+ if (id != tree_id) {
+ errno = ENOENT;
+ return BTRFS_UTIL_ERROR_SUBVOLUME_NOT_FOUND;
+ }
+
+ return BTRFS_UTIL_OK;
+}
+
static enum btrfs_util_error append_to_search_stack(struct btrfs_util_subvolume_iterator *iter,
uint64_t tree_id,
size_t path_len)
@@ -786,24 +853,84 @@ static enum btrfs_util_error append_to_search_stack(struct btrfs_util_subvolume_
iter->search_stack = new_search_stack;
}
- entry = &iter->search_stack[iter->search_stack_len++];
+ entry = &iter->search_stack[iter->search_stack_len];
- memset(&entry->search, 0, sizeof(entry->search));
- entry->search.key.tree_id = BTRFS_ROOT_TREE_OBJECTID;
- entry->search.key.min_objectid = tree_id;
- entry->search.key.max_objectid = tree_id;
- entry->search.key.min_type = BTRFS_ROOT_REF_KEY;
- entry->search.key.max_type = BTRFS_ROOT_REF_KEY;
- entry->search.key.min_offset = 0;
- entry->search.key.max_offset = UINT64_MAX;
- entry->search.key.min_transid = 0;
- entry->search.key.max_transid = UINT64_MAX;
- entry->search.key.nr_items = 0;
+ memset(entry, 0, sizeof(*entry));
+ entry->path_len = path_len;
+ if (iter->use_tree_search) {
+ entry->search.key.tree_id = BTRFS_ROOT_TREE_OBJECTID;
+ entry->search.key.min_objectid = tree_id;
+ entry->search.key.max_objectid = tree_id;
+ entry->search.key.min_type = BTRFS_ROOT_REF_KEY;
+ entry->search.key.max_type = BTRFS_ROOT_REF_KEY;
+ entry->search.key.min_offset = 0;
+ entry->search.key.max_offset = UINT64_MAX;
+ entry->search.key.min_transid = 0;
+ entry->search.key.max_transid = UINT64_MAX;
+ entry->search.key.nr_items = 0;
+ } else {
+ entry->id = tree_id;
- entry->items_pos = 0;
- entry->buf_off = 0;
+ if (iter->search_stack_len) {
+ struct search_stack_entry *top;
+ enum btrfs_util_error err;
+ char *path;
+ int fd;
- entry->path_len = path_len;
+ top = top_search_stack_entry(iter);
+ path = &iter->cur_path[top->path_len];
+ if (*path == '/')
+ path++;
+ fd = openat(iter->cur_fd, path, O_RDONLY);
+ if (fd == -1)
+ return BTRFS_UTIL_ERROR_OPEN_FAILED;
+
+ err = check_expected_subvolume(fd, iter->cur_fd,
+ tree_id);
+ if (err) {
+ close(fd);
+ return err;
+ }
+
+ close(iter->cur_fd);
+ iter->cur_fd = fd;
+ }
+ }
+
+ iter->search_stack_len++;
+
+ return BTRFS_UTIL_OK;
+}
+
+static enum btrfs_util_error pop_search_stack(struct btrfs_util_subvolume_iterator *iter)
+{
+ struct search_stack_entry *top, *parent;
+ int fd, parent_fd;
+ size_t i;
+
+ if (iter->use_tree_search || iter->search_stack_len == 1) {
+ iter->search_stack_len--;
+ return BTRFS_UTIL_OK;
+ }
+
+ top = top_search_stack_entry(iter);
+ iter->search_stack_len--;
+ parent = top_search_stack_entry(iter);
+
+ fd = iter->cur_fd;
+ for (i = parent->path_len; i < top->path_len; i++) {
+ if (i == 0 || iter->cur_path[i] == '/') {
+ parent_fd = openat(fd, "..", O_RDONLY);
+ if (fd != iter->cur_fd)
+ SAVE_ERRNO_AND_CLOSE(fd);
+ if (parent_fd == -1)
+ return BTRFS_UTIL_ERROR_OPEN_FAILED;
+ fd = parent_fd;
+ }
+ }
+ if (iter->cur_fd != iter->fd)
+ close(iter->cur_fd);
+ iter->cur_fd = fd;
return BTRFS_UTIL_OK;
}
@@ -836,12 +963,14 @@ PUBLIC enum btrfs_util_error btrfs_util_create_subvolume_iterator_fd(int fd,
{
struct btrfs_util_subvolume_iterator *iter;
enum btrfs_util_error err;
+ bool use_tree_search;
if (flags & ~BTRFS_UTIL_SUBVOLUME_ITERATOR_MASK) {
errno = EINVAL;
return BTRFS_UTIL_ERROR_INVALID_ARGUMENT;
}
+ use_tree_search = top != 0 || is_root();
if (top == 0) {
err = btrfs_util_is_subvolume_fd(fd);
if (err)
@@ -857,7 +986,9 @@ PUBLIC enum btrfs_util_error btrfs_util_create_subvolume_iterator_fd(int fd,
return BTRFS_UTIL_ERROR_NO_MEMORY;
iter->fd = fd;
+ iter->cur_fd = fd;
iter->flags = flags;
+ iter->use_tree_search = use_tree_search;
iter->search_stack_len = 0;
iter->search_stack_capacity = 4;
@@ -1166,6 +1297,8 @@ PUBLIC void btrfs_util_destroy_subvolume_iterator(struct btrfs_util_subvolume_it
if (iter) {
free(iter->cur_path);
free(iter->search_stack);
+ if (iter->cur_fd != iter->fd)
+ SAVE_ERRNO_AND_CLOSE(iter->cur_fd);
if (iter->flags & BTRFS_UTIL_SUBVOLUME_ITERATOR_CLOSE_FD)
SAVE_ERRNO_AND_CLOSE(iter->fd);
free(iter);
@@ -1177,32 +1310,14 @@ PUBLIC int btrfs_util_subvolume_iterator_fd(const struct btrfs_util_subvolume_it
return iter->fd;
}
-static struct search_stack_entry *top_search_stack_entry(struct btrfs_util_subvolume_iterator *iter)
-{
- return &iter->search_stack[iter->search_stack_len - 1];
-}
-
static enum btrfs_util_error build_subvol_path(struct btrfs_util_subvolume_iterator *iter,
- const struct btrfs_ioctl_search_header *header,
- const struct btrfs_root_ref *ref,
- const char *name,
+ const char *name, size_t name_len,
+ const char *dir, size_t dir_len,
size_t *path_len_ret)
{
- struct btrfs_ioctl_ino_lookup_args lookup = {
- .treeid = header->objectid,
- .objectid = le64_to_cpu(ref->dirid),
- };
struct search_stack_entry *top = top_search_stack_entry(iter);
- size_t dir_len, name_len, path_len;
+ size_t path_len;
char *p;
- int ret;
-
- ret = ioctl(iter->fd, BTRFS_IOC_INO_LOOKUP, &lookup);
- if (ret == -1)
- return BTRFS_UTIL_ERROR_INO_LOOKUP_FAILED;
-
- dir_len = strlen(lookup.name);
- name_len = le16_to_cpu(ref->name_len);
path_len = top->path_len;
/*
@@ -1220,33 +1335,75 @@ static enum btrfs_util_error build_subvol_path(struct btrfs_util_subvolume_itera
path_len++;
path_len += name_len;
- if (path_len > iter->cur_path_capacity) {
- char *tmp = realloc(iter->cur_path, path_len);
+ /* We need one extra character for the NUL terminator. */
+ if (path_len + 1 > iter->cur_path_capacity) {
+ char *tmp = realloc(iter->cur_path, path_len + 1);
if (!tmp)
return BTRFS_UTIL_ERROR_NO_MEMORY;
iter->cur_path = tmp;
- iter->cur_path_capacity = path_len;
+ iter->cur_path_capacity = path_len + 1;
}
p = iter->cur_path + top->path_len;
if (top->path_len && dir_len)
*p++ = '/';
- memcpy(p, lookup.name, dir_len);
+ memcpy(p, dir, dir_len);
p += dir_len;
if (top->path_len && !dir_len && name_len)
*p++ = '/';
memcpy(p, name, name_len);
p += name_len;
+ *p = '\0';
*path_len_ret = path_len;
return BTRFS_UTIL_OK;
}
-PUBLIC enum btrfs_util_error btrfs_util_subvolume_iterator_next(struct btrfs_util_subvolume_iterator *iter,
- char **path_ret,
- uint64_t *id_ret)
+static enum btrfs_util_error build_subvol_path_privileged(struct btrfs_util_subvolume_iterator *iter,
+ const struct btrfs_ioctl_search_header *header,
+ const struct btrfs_root_ref *ref,
+ const char *name,
+ size_t *path_len_ret)
+{
+ struct btrfs_ioctl_ino_lookup_args lookup = {
+ .treeid = header->objectid,
+ .objectid = le64_to_cpu(ref->dirid),
+ };
+ int ret;
+
+ ret = ioctl(iter->fd, BTRFS_IOC_INO_LOOKUP, &lookup);
+ if (ret == -1)
+ return BTRFS_UTIL_ERROR_INO_LOOKUP_FAILED;
+
+ return build_subvol_path(iter, name, le16_to_cpu(ref->name_len),
+ lookup.name, strlen(lookup.name),
+ path_len_ret);
+}
+
+static enum btrfs_util_error build_subvol_path_unprivileged(struct btrfs_util_subvolume_iterator *iter,
+ uint64_t treeid,
+ uint64_t dirid,
+ size_t *path_len_ret)
+{
+ struct btrfs_ioctl_ino_lookup_user_args args = {
+ .treeid = treeid,
+ .dirid = dirid,
+ };
+ int ret;
+
+ ret = ioctl(iter->cur_fd, BTRFS_IOC_INO_LOOKUP_USER, &args);
+ if (ret == -1)
+ return BTRFS_UTIL_ERROR_INO_LOOKUP_USER_FAILED;
+
+ return build_subvol_path(iter, args.name, strlen(args.name),
+ args.path, strlen(args.path), path_len_ret);
+}
+
+static enum btrfs_util_error subvolume_iterator_next_tree_search(struct btrfs_util_subvolume_iterator *iter,
+ char **path_ret,
+ uint64_t *id_ret)
{
struct search_stack_entry *top;
const struct btrfs_ioctl_search_header *header;
@@ -1273,7 +1430,10 @@ PUBLIC enum btrfs_util_error btrfs_util_subvolume_iterator_next(struct btrfs_uti
top->buf_off = 0;
if (top->search.key.nr_items == 0) {
- iter->search_stack_len--;
+ /*
+ * This never fails for use_tree_search.
+ */
+ pop_search_stack(iter);
if ((iter->flags & BTRFS_UTIL_SUBVOLUME_ITERATOR_POST_ORDER) &&
iter->search_stack_len)
goto out;
@@ -1293,7 +1453,8 @@ PUBLIC enum btrfs_util_error btrfs_util_subvolume_iterator_next(struct btrfs_uti
ref = (struct btrfs_root_ref *)(header + 1);
name = (const char *)(ref + 1);
- err = build_subvol_path(iter, header, ref, name, &path_len);
+ err = build_subvol_path_privileged(iter, header, ref, name,
+ &path_len);
if (err)
return err;
@@ -1320,6 +1481,100 @@ out:
return BTRFS_UTIL_OK;
}
+static enum btrfs_util_error subvolume_iterator_next_unprivileged(struct btrfs_util_subvolume_iterator *iter,
+ char **path_ret,
+ uint64_t *id_ret)
+{
+ struct search_stack_entry *top;
+ uint64_t treeid, dirid;
+ enum btrfs_util_error err;
+ size_t path_len;
+ int ret;
+
+ for (;;) {
+ for (;;) {
+ if (iter->search_stack_len == 0)
+ return BTRFS_UTIL_ERROR_STOP_ITERATION;
+
+ top = top_search_stack_entry(iter);
+ if (top->items_pos < top->rootref_args.num_items) {
+ break;
+ } else {
+ ret = ioctl(iter->cur_fd,
+ BTRFS_IOC_GET_SUBVOL_ROOTREF,
+ &top->rootref_args);
+ if (ret == -1 && errno != EOVERFLOW)
+ return BTRFS_UTIL_ERROR_GET_SUBVOL_ROOTREF_FAILED;
+ top->items_pos = 0;
+
+ if (top->rootref_args.num_items == 0) {
+ err = pop_search_stack(iter);
+ if (err)
+ return err;
+ if ((iter->flags & BTRFS_UTIL_SUBVOLUME_ITERATOR_POST_ORDER) &&
+ iter->search_stack_len)
+ goto out;
+ }
+ }
+ }
+
+ treeid = top->rootref_args.rootref[top->items_pos].treeid;
+ dirid = top->rootref_args.rootref[top->items_pos].dirid;
+ top->items_pos++;
+ err = build_subvol_path_unprivileged(iter, treeid, dirid,
+ &path_len);
+ if (err) {
+ /* Skip the subvolume if we can't access it. */
+ if (errno == EACCES)
+ continue;
+ return err;
+ }
+
+ err = append_to_search_stack(iter, treeid, path_len);
+ if (err) {
+ /*
+ * Skip the subvolume if it does not exist (which can
+ * happen if there is another filesystem mounted over a
+ * parent directory) or we don't have permission to
+ * access it.
+ */
+ if (errno == ENOENT || errno == EACCES)
+ continue;
+ return err;
+ }
+
+ if (!(iter->flags & BTRFS_UTIL_SUBVOLUME_ITERATOR_POST_ORDER)) {
+ top = top_search_stack_entry(iter);
+ goto out;
+ }
+ }
+
+out:
+ if (path_ret) {
+ *path_ret = malloc(top->path_len + 1);
+ if (!*path_ret)
+ return BTRFS_UTIL_ERROR_NO_MEMORY;
+ memcpy(*path_ret, iter->cur_path, top->path_len);
+ (*path_ret)[top->path_len] = '\0';
+ }
+ if (id_ret)
+ *id_ret = top->id;
+ return BTRFS_UTIL_OK;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_subvolume_iterator_next(struct btrfs_util_subvolume_iterator *iter,
+ char **path_ret,
+ uint64_t *id_ret)
+{
+ if (iter->use_tree_search) {
+ return subvolume_iterator_next_tree_search(iter, path_ret,
+ id_ret);
+ } else {
+ return subvolume_iterator_next_unprivileged(iter, path_ret,
+ id_ret);
+ }
+}
+
PUBLIC enum btrfs_util_error btrfs_util_subvolume_iterator_next_info(struct btrfs_util_subvolume_iterator *iter,
char **path_ret,
struct btrfs_util_subvolume_info *subvol)
@@ -1331,7 +1586,10 @@ PUBLIC enum btrfs_util_error btrfs_util_subvolume_iterator_next_info(struct btrf
if (err)
return err;
- return btrfs_util_subvolume_info_fd(iter->fd, id, subvol);
+ if (iter->use_tree_search)
+ return btrfs_util_subvolume_info_fd(iter->fd, id, subvol);
+ else
+ return btrfs_util_subvolume_info_fd(iter->cur_fd, 0, subvol);
}
PUBLIC enum btrfs_util_error btrfs_util_deleted_subvolumes(const char *path,