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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>
This commit is contained in:
Omar Sandoval 2018-11-13 23:47:03 -08:00 committed by David Sterba
parent bfe2dc3796
commit 2a74c0e4ee
4 changed files with 456 additions and 111 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
libbtrfsutil/btrfsutil.h
View File

@ -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().
*/

6
libbtrfsutil/errors.c
View File

@ -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)

190
libbtrfsutil/python/tests/test_subvolume.py
View File

@ -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):
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)])
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)
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()
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:
self.assertEqual(list(it), subvols)
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)])
subvols = [
('bar', 257),
('bar/baz', 258),
]
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)
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()
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)

356
libbtrfsutil/subvolume.c
View File

@ -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++];
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;
entry->items_pos = 0;
entry->buf_off = 0;
entry = &iter->search_stack[iter->search_stack_len];
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;
if (iter->search_stack_len) {
struct search_stack_entry *top;
enum btrfs_util_error err;
char *path;
int fd;
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,