1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
//! Btrfs filesystem lookups
use crate::{
bindings::{
BTRFS_FIRST_FREE_OBJECTID, BTRFS_IOC_INO_LOOKUP, BTRFS_IOC_INO_LOOKUP_USER,
btrfs_ioctl_ino_lookup_args, btrfs_ioctl_ino_lookup_user_args,
},
util::{IoError, IoResult, KernelStr, OptionFd, btrfs_ioctl},
};
#[allow(unused_imports)]
use std::io::ErrorKind;
use std::os::fd::BorrowedFd;
use std::{ffi::CStr, fs::File, mem::MaybeUninit, os::fd::AsFd, path::Path, ptr};
/// Userspace lookup buffer
pub struct UserLookup<'r>(MaybeUninit<btrfs_ioctl_ino_lookup_user_args>, OptionFd<'r>);
impl<'r> From<BorrowedFd<'r>> for UserLookup<'r>
{
/// Initialise a userspace lookup buffer from a raw file descriptor.
/// The file descriptor will not be closed when `Lookup` instance is dropped
#[inline(always)]
fn from(value: BorrowedFd<'r>) -> Self
{
Self(MaybeUninit::uninit(), OptionFd::Borrowed(value))
}
}
impl TryFrom<&str> for UserLookup<'_>
{
type Error = IoError;
#[inline(always)]
fn try_from(value: &str) -> Result<Self, Self::Error>
{
Self::try_from(Path::new(value))
}
}
impl TryFrom<&Path> for UserLookup<'_>
{
type Error = IoError;
#[inline(always)]
fn try_from(value: &Path) -> Result<Self, Self::Error>
{
File::open(value).map(|f| Self(MaybeUninit::uninit(), OptionFd::Owned(f.into())))
}
}
impl UserLookup<'_>
{
/// Lookup the path from a subvolume root
///
/// This function is equivelent to `UserLookup::path_as_str()` execept returns bytes
/// instead of a `&str`.
pub fn path_bytes(&mut self, dirid: u64, treeid: u64) -> IoResult<(&[u8], &[u8])>
{
unsafe {
let arg_ptr = self.0.as_mut_ptr();
let path_ptr = &raw mut (*arg_ptr).path;
let name_ptr = &raw mut (*arg_ptr).name;
ptr::write(&raw mut (*arg_ptr).dirid, dirid);
ptr::write(&raw mut (*arg_ptr).treeid, treeid);
ptr::write_bytes(name_ptr, 0, 1);
ptr::write_bytes(path_ptr, 0, 1);
btrfs_ioctl(self.1.as_fd(), BTRFS_IOC_INO_LOOKUP_USER, arg_ptr)?;
Ok((
CStr::from_ptr(path_ptr.cast()).to_bytes(),
CStr::from_ptr(name_ptr.cast()).to_bytes(),
))
}
}
/// Lookup the path from a subvolume root
///
/// Returns a lookup path and name for the subvolume referenced by `treeid`. `dirid` is the inode
/// of the directory in which the subvolume is rooted. The path is relative to the path or file
/// descriptor used to construct the `UserLookup` instance.
///
/// # Errors
///
/// [`ErrorKind::NotFound`]
///
/// > The subvolume referenced by the underlying path or file descriptor used to construct the
/// `UserLookup` instance, does not contain the inode given by `dirid` or a subvolumeID given
/// by `treeid`.
///
/// [`ErrorKind::InvalidInput`]
///
/// > `dirid` is not the directory in which the subvolume, `treeid` is rooted.
pub fn path_str(&mut self, dirid: u64, treeid: u64)
-> IoResult<(KernelStr<'_>, KernelStr<'_>)>
{
unsafe {
let arg_ptr = self.0.as_mut_ptr();
let path_ptr = &raw mut (*arg_ptr).path;
let name_ptr = &raw mut (*arg_ptr).name;
ptr::write(&raw mut (*arg_ptr).dirid, dirid);
ptr::write(&raw mut (*arg_ptr).treeid, treeid);
ptr::write_bytes(name_ptr, 0, 1);
ptr::write_bytes(path_ptr, 0, 1);
btrfs_ioctl(self.1.as_fd(), BTRFS_IOC_INO_LOOKUP_USER, arg_ptr)?;
Ok((
CStr::from_ptr(path_ptr.cast()).to_string_lossy(),
CStr::from_ptr(name_ptr.cast()).to_string_lossy(),
))
}
}
}
/// Lookup buffer
pub struct Lookup<'r>(MaybeUninit<btrfs_ioctl_ino_lookup_args>, OptionFd<'r>);
impl<'r> From<BorrowedFd<'r>> for Lookup<'r>
{
/// Initialise a lookup buffer from a raw file descriptor. The file descriptor will
/// not be closed when `Lookup` instance is dropped
#[inline(always)]
fn from(value: BorrowedFd<'r>) -> Self
{
Self(MaybeUninit::uninit(), OptionFd::Borrowed(value))
}
}
impl TryFrom<&str> for Lookup<'_>
{
type Error = IoError;
#[inline(always)]
fn try_from(value: &str) -> Result<Self, Self::Error>
{
Self::try_from(Path::new(value))
}
}
impl TryFrom<&Path> for Lookup<'_>
{
type Error = IoError;
#[inline(always)]
fn try_from(value: &Path) -> Result<Self, Self::Error>
{
File::open(value).map(|f| Self(MaybeUninit::uninit(), OptionFd::Owned(f.into())))
}
}
impl Lookup<'_>
{
/// Lookup the treeid for the subvolume referenced by the underlying path or file descriptor.
pub fn treeid(&mut self) -> IoResult<u64>
{
unsafe {
let arg_ptr = self.0.as_mut_ptr();
ptr::write(&raw mut (*arg_ptr).objectid, BTRFS_FIRST_FREE_OBJECTID);
ptr::write(&raw mut (*arg_ptr).treeid, 0);
ptr::write_bytes(&raw mut (*arg_ptr).name, 0, 1);
btrfs_ioctl(self.1.as_fd(), BTRFS_IOC_INO_LOOKUP, arg_ptr).map(|_| (*arg_ptr).treeid)
}
}
/// Lookup path from an inode to a subvolume root
///
/// This function retrurns a lookup path as a string slice to `objectid` which is the inode of a
/// file or directory which must be containded in the subvolume referenced by `treeid`. The returned
/// path is relative to the subvolume referenced by `treeid`. `objectid` and `treeid` must both be
/// within the btrfs filesystem referenced by `fs`.
///
/// # Errors
///
/// [`ErrorKind::InvalidData`]
///
/// > The path to be returned contained invalid UTF-8.
///
/// # Notes
///
/// **Requires CAP_SYS_ADMIN capabilities**
pub fn path_str(&mut self, objectid: u64, treeid: u64) -> IoResult<KernelStr<'_>>
{
unsafe {
let args = self.0.as_mut_ptr();
let name = &raw mut (*args).name;
ptr::write(&raw mut (*args).objectid, objectid);
ptr::write(&raw mut (*args).treeid, treeid);
ptr::write_bytes(name, 0, 1);
btrfs_ioctl(self.1.as_fd(), BTRFS_IOC_INO_LOOKUP, args)?;
Ok(CStr::from_ptr(name.cast()).to_string_lossy())
}
}
/// Lookup path from an inode to a subvolume root
///
/// This function retrurns a lookup path as a byte slice to `objectid` which is the inode of a
/// file or directory which must be containded in the subvolume referenced by `treeid`. The returned
/// path is relative to the subvolume referenced by `treeid`. `objectid` and `treeid` must both be
/// within the btrfs filesystem referenced by `fs`.
///
/// # Notes
///
/// **Requires CAP_SYS_ADMIN capabilities**
pub fn path_bytes(&mut self, objectid: u64, treeid: u64) -> IoResult<&[u8]>
{
unsafe {
let args = self.0.as_mut_ptr();
let name = &raw mut (*args).name;
ptr::write(&raw mut (*args).objectid, objectid);
ptr::write(&raw mut (*args).treeid, treeid);
ptr::write_bytes(name, 0, 1);
btrfs_ioctl(self.1.as_fd(), BTRFS_IOC_INO_LOOKUP, args)?;
Ok(CStr::from_ptr(name.cast()).to_bytes())
}
}
}