1//! Linux `statx`.
2
3use crate::fd::AsFd;
4use crate::fs::AtFlags;
5use crate::{backend, io, path};
6use backend::c;
7use bitflags::bitflags;
8
9#[cfg(feature = "linux_4_11")]
10use backend::fs::syscalls::statx as _statx;
11#[cfg(not(feature = "linux_4_11"))]
12use compat::statx as _statx;
13
14/// `struct statx` for use with [`statx`].
15#[repr(C)]
16#[derive(Debug, Copy, Clone)]
17#[allow(missing_docs)]
18#[non_exhaustive]
19pub struct Statx {
20 pub stx_mask: u32,
21 pub stx_blksize: u32,
22 pub stx_attributes: StatxAttributes,
23 pub stx_nlink: u32,
24 pub stx_uid: u32,
25 pub stx_gid: u32,
26 pub stx_mode: u16,
27 pub(crate) __spare0: [u16; 1],
28 pub stx_ino: u64,
29 pub stx_size: u64,
30 pub stx_blocks: u64,
31 pub stx_attributes_mask: StatxAttributes,
32 pub stx_atime: StatxTimestamp,
33 pub stx_btime: StatxTimestamp,
34 pub stx_ctime: StatxTimestamp,
35 pub stx_mtime: StatxTimestamp,
36 pub stx_rdev_major: u32,
37 pub stx_rdev_minor: u32,
38 pub stx_dev_major: u32,
39 pub stx_dev_minor: u32,
40 pub stx_mnt_id: u64,
41 pub stx_dio_mem_align: u32,
42 pub stx_dio_offset_align: u32,
43 pub stx_subvol: u64,
44 pub stx_atomic_write_unit_min: u32,
45 pub stx_atomic_write_unit_max: u32,
46 pub stx_atomic_write_segments_max: u32,
47 pub(crate) __spare1: [u32; 1],
48 pub(crate) __spare3: [u64; 9],
49}
50
51/// `struct statx_timestamp` for use with [`Statx`].
52#[repr(C)]
53#[derive(Debug, Copy, Clone)]
54#[non_exhaustive]
55pub struct StatxTimestamp {
56 /// Seconds.
57 pub tv_sec: i64,
58
59 /// Nanoseconds. Must be less than 1_000_000_000.
60 pub tv_nsec: u32,
61
62 pub(crate) __reserved: i32,
63}
64
65bitflags! {
66 /// `STATX_*` constants for use with [`statx`].
67 ///
68 /// [`statx`]: crate::fs::statx
69 #[repr(transparent)]
70 #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
71 pub struct StatxFlags: u32 {
72 /// `STATX_TYPE`
73 const TYPE = c::STATX_TYPE;
74
75 /// `STATX_MODE`
76 const MODE = c::STATX_MODE;
77
78 /// `STATX_NLINK`
79 const NLINK = c::STATX_NLINK;
80
81 /// `STATX_UID`
82 const UID = c::STATX_UID;
83
84 /// `STATX_GID`
85 const GID = c::STATX_GID;
86
87 /// `STATX_ATIME`
88 const ATIME = c::STATX_ATIME;
89
90 /// `STATX_MTIME`
91 const MTIME = c::STATX_MTIME;
92
93 /// `STATX_CTIME`
94 const CTIME = c::STATX_CTIME;
95
96 /// `STATX_INO`
97 const INO = c::STATX_INO;
98
99 /// `STATX_SIZE`
100 const SIZE = c::STATX_SIZE;
101
102 /// `STATX_BLOCKS`
103 const BLOCKS = c::STATX_BLOCKS;
104
105 /// `STATX_BASIC_STATS`
106 const BASIC_STATS = c::STATX_BASIC_STATS;
107
108 /// `STATX_BTIME`
109 const BTIME = c::STATX_BTIME;
110
111 /// `STATX_MNT_ID` (since Linux 5.8)
112 const MNT_ID = c::STATX_MNT_ID;
113
114 /// `STATX_DIOALIGN` (since Linux 6.1)
115 const DIOALIGN = c::STATX_DIOALIGN;
116
117 /// `STATX_ALL`
118 const ALL = c::STATX_ALL;
119
120 /// <https://docs.rs/bitflags/*/bitflags/#externally-defined-flags>
121 const _ = !0;
122 }
123}
124
125bitflags! {
126 /// `STATX_ATTR_*` flags for use with [`Statx`].
127 #[repr(transparent)]
128 #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
129 pub struct StatxAttributes: u64 {
130 /// `STATX_ATTR_COMPRESSED`
131 const COMPRESSED = c::STATX_ATTR_COMPRESSED as u64;
132
133 /// `STATX_ATTR_IMMUTABLE`
134 const IMMUTABLE = c::STATX_ATTR_IMMUTABLE as u64;
135
136 /// `STATX_ATTR_APPEND`
137 const APPEND = c::STATX_ATTR_APPEND as u64;
138
139 /// `STATX_ATTR_NODUMP`
140 const NODUMP = c::STATX_ATTR_NODUMP as u64;
141
142 /// `STATX_ATTR_ENCRYPTED`
143 const ENCRYPTED = c::STATX_ATTR_ENCRYPTED as u64;
144
145 /// `STATX_ATTR_AUTOMOUNT`
146 const AUTOMOUNT = c::STATX_ATTR_AUTOMOUNT as u64;
147
148 /// `STATX_ATTR_MOUNT_ROOT`
149 const MOUNT_ROOT = c::STATX_ATTR_MOUNT_ROOT as u64;
150
151 /// `STATX_ATTR_VERITY`
152 const VERITY = c::STATX_ATTR_VERITY as u64;
153
154 /// `STATX_ATTR_DAX`
155 const DAX = c::STATX_ATTR_DAX as u64;
156
157 /// <https://docs.rs/bitflags/*/bitflags/#externally-defined-flags>
158 const _ = !0;
159 }
160}
161
162/// `statx(dirfd, path, flags, mask, statxbuf)`—Extended `stat`.
163///
164/// This function returns [`io::Errno::NOSYS`] if `statx` is not available on
165/// the platform, such as Linux before 4.11. This also includes older Docker
166/// versions where the actual syscall fails with different error codes; rustix
167/// handles this and translates them into `NOSYS`.
168///
169/// # References
170/// - [Linux]
171///
172/// # Examples
173///
174/// ```
175/// # use std::path::Path;
176/// # use std::io;
177/// # use rustix::fs::{AtFlags, StatxFlags};
178/// # use rustix::fd::BorrowedFd;
179/// /// Try to determine if the provided path is a mount root. Will return
180/// /// `Ok(None)` if the kernel is not new enough to support `statx` or
181/// /// [`StatxAttributes::MOUNT_ROOT`].
182/// fn is_mountpoint(root: BorrowedFd<'_>, path: &Path) -> io::Result<Option<bool>> {
183/// use rustix::fs::{AtFlags, StatxAttributes, StatxFlags};
184///
185/// match rustix::fs::statx(
186/// root,
187/// path,
188/// AtFlags::NO_AUTOMOUNT | AtFlags::SYMLINK_NOFOLLOW,
189/// StatxFlags::empty(),
190/// ) {
191/// Ok(r) => {
192/// let present = r.stx_attributes_mask.contains(StatxAttributes::MOUNT_ROOT);
193/// Ok(present.then(|| r.stx_attributes.contains(StatxAttributes::MOUNT_ROOT)))
194/// }
195/// Err(rustix::io::Errno::NOSYS) => Ok(None),
196/// Err(e) => Err(e.into()),
197/// }
198/// }
199/// ```
200///
201/// [Linux]: https://man7.org/linux/man-pages/man2/statx.2.html
202#[inline]
203pub fn statx<P: path::Arg, Fd: AsFd>(
204 dirfd: Fd,
205 path: P,
206 flags: AtFlags,
207 mask: StatxFlags,
208) -> io::Result<Statx> {
209 path.into_with_c_str(|path: &CStr| _statx(dirfd.as_fd(), path, flags, mask))
210}
211
212#[cfg(not(feature = "linux_4_11"))]
213mod compat {
214 use crate::fd::BorrowedFd;
215 use crate::ffi::CStr;
216 use crate::fs::{AtFlags, Statx, StatxFlags};
217 use crate::{backend, io};
218 use core::sync::atomic::{AtomicU8, Ordering};
219
220 // Linux kernel prior to 4.11 and old versions of Docker don't support
221 // `statx`. We store the availability in a global to avoid unnecessary
222 // syscalls.
223 //
224 // 0: Unknown
225 // 1: Not available
226 // 2: Available
227 static STATX_STATE: AtomicU8 = AtomicU8::new(0);
228
229 #[inline]
230 pub fn statx(
231 dirfd: BorrowedFd<'_>,
232 path: &CStr,
233 flags: AtFlags,
234 mask: StatxFlags,
235 ) -> io::Result<Statx> {
236 match STATX_STATE.load(Ordering::Relaxed) {
237 0 => statx_init(dirfd, path, flags, mask),
238 1 => Err(io::Errno::NOSYS),
239 _ => backend::fs::syscalls::statx(dirfd, path, flags, mask),
240 }
241 }
242
243 /// The first `statx` call. We don't know if `statx` is available yet.
244 fn statx_init(
245 dirfd: BorrowedFd<'_>,
246 path: &CStr,
247 flags: AtFlags,
248 mask: StatxFlags,
249 ) -> io::Result<Statx> {
250 match backend::fs::syscalls::statx(dirfd, path, flags, mask) {
251 Err(err) => statx_error(err),
252 result => {
253 STATX_STATE.store(2, Ordering::Relaxed);
254 result
255 }
256 }
257 }
258
259 /// The first `statx` call failed. We can get a variety of error codes
260 /// from seccomp configs or faulty FUSE drivers, so we don't trust
261 /// `ENOSYS` or `EPERM` to tell us whether statx is available.
262 #[cold]
263 fn statx_error(err: io::Errno) -> io::Result<Statx> {
264 if backend::fs::syscalls::is_statx_available() {
265 // Statx is available. Record this, and fail with the error
266 // code of the initial `statx` call.
267 STATX_STATE.store(2, Ordering::Relaxed);
268 Err(err)
269 } else {
270 // Statx is not available. Record this, and fail with `NOSYS`.
271 STATX_STATE.store(1, Ordering::Relaxed);
272 Err(io::Errno::NOSYS)
273 }
274 }
275}
276