From 1b6a04ca5504955c571d1c97504fb45ea0befee4 Mon Sep 17 00:00:00 2001
From: Valentin Popov <valentin@popov.link>
Date: Mon, 8 Jan 2024 01:21:28 +0400
Subject: Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>
---
 vendor/rustix/src/fs/statx.rs | 135 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)
 create mode 100644 vendor/rustix/src/fs/statx.rs

(limited to 'vendor/rustix/src/fs/statx.rs')

diff --git a/vendor/rustix/src/fs/statx.rs b/vendor/rustix/src/fs/statx.rs
new file mode 100644
index 0000000..b7d6787
--- /dev/null
+++ b/vendor/rustix/src/fs/statx.rs
@@ -0,0 +1,135 @@
+//! Linux `statx`.
+
+use crate::fd::AsFd;
+use crate::fs::AtFlags;
+use crate::{backend, io, path};
+use backend::fs::types::{Statx, StatxFlags};
+
+#[cfg(feature = "linux_4_11")]
+use backend::fs::syscalls::statx as _statx;
+#[cfg(not(feature = "linux_4_11"))]
+use compat::statx as _statx;
+
+/// `statx(dirfd, path, flags, mask, statxbuf)`
+///
+/// This function returns [`io::Errno::NOSYS`] if `statx` is not available on
+/// the platform, such as Linux before 4.11. This also includes older Docker
+/// versions where the actual syscall fails with different error codes; rustix
+/// handles this and translates them into `NOSYS`.
+///
+/// # References
+///  - [Linux]
+///
+/// # Examples
+///
+/// ```
+/// # use std::path::Path;
+/// # use std::io;
+/// # use rustix::fs::{AtFlags, StatxFlags};
+/// # use rustix::fd::BorrowedFd;
+/// /// Try to determine if the provided path is a mount root. Will return
+/// /// `Ok(None)` if the kernel is not new enough to support `statx` or
+/// /// [`libc::STATX_ATTR_MOUNT_ROOT`].
+/// fn is_mountpoint(root: BorrowedFd<'_>, path: &Path) -> io::Result<Option<bool>> {
+///     use rustix::fs::{AtFlags, StatxFlags};
+///
+///     let mountroot_flag = libc::STATX_ATTR_MOUNT_ROOT as u64;
+///     match rustix::fs::statx(
+///         root,
+///         path,
+///         AtFlags::NO_AUTOMOUNT | AtFlags::SYMLINK_NOFOLLOW,
+///         StatxFlags::empty(),
+///     ) {
+///         Ok(r) => {
+///             let present = (r.stx_attributes_mask & mountroot_flag) > 0;
+///             Ok(present.then(|| r.stx_attributes & mountroot_flag > 0))
+///         }
+///         Err(e) if e == rustix::io::Errno::NOSYS => Ok(None),
+///         Err(e) => Err(e.into()),
+///     }
+/// }
+/// ```
+///
+/// [Linux]: https://man7.org/linux/man-pages/man2/statx.2.html
+#[inline]
+pub fn statx<P: path::Arg, Fd: AsFd>(
+    dirfd: Fd,
+    path: P,
+    flags: AtFlags,
+    mask: StatxFlags,
+) -> io::Result<Statx> {
+    path.into_with_c_str(|path| _statx(dirfd.as_fd(), path, flags, mask))
+}
+
+#[cfg(not(feature = "linux_4_11"))]
+mod compat {
+    use crate::fd::BorrowedFd;
+    use crate::ffi::CStr;
+    use crate::fs::AtFlags;
+    use crate::{backend, io};
+    use core::sync::atomic::{AtomicU8, Ordering};
+
+    use backend::fs::types::{Statx, StatxFlags};
+
+    // Linux kernel prior to 4.11 and old versions of Docker don't support
+    // `statx`. We store the availability in a global to avoid unnecessary
+    // syscalls.
+    //
+    // 0: Unknown
+    // 1: Not available
+    // 2: Available
+    static STATX_STATE: AtomicU8 = AtomicU8::new(0);
+
+    #[inline]
+    pub fn statx(
+        dirfd: BorrowedFd<'_>,
+        path: &CStr,
+        flags: AtFlags,
+        mask: StatxFlags,
+    ) -> io::Result<Statx> {
+        match STATX_STATE.load(Ordering::Relaxed) {
+            0 => statx_init(dirfd, path, flags, mask),
+            1 => Err(io::Errno::NOSYS),
+            _ => backend::fs::syscalls::statx(dirfd, path, flags, mask),
+        }
+    }
+
+    /// The first `statx` call. We don't know if `statx` is available yet.
+    fn statx_init(
+        dirfd: BorrowedFd<'_>,
+        path: &CStr,
+        flags: AtFlags,
+        mask: StatxFlags,
+    ) -> io::Result<Statx> {
+        match backend::fs::syscalls::statx(dirfd, path, flags, mask) {
+            Err(io::Errno::NOSYS) => statx_error_nosys(),
+            Err(io::Errno::PERM) => statx_error_perm(),
+            result => {
+                STATX_STATE.store(2, Ordering::Relaxed);
+                result
+            }
+        }
+    }
+
+    /// The first `statx` call failed with `NOSYS` (or something we're treating
+    /// like `NOSYS`).
+    #[cold]
+    fn statx_error_nosys() -> io::Result<Statx> {
+        STATX_STATE.store(1, Ordering::Relaxed);
+        Err(io::Errno::NOSYS)
+    }
+
+    /// The first `statx` call failed with `PERM`.
+    #[cold]
+    fn statx_error_perm() -> io::Result<Statx> {
+        // Some old versions of Docker have `statx` fail with `PERM` when it
+        // isn't recognized. Check whether `statx` really is available, and if
+        // so, fail with `PERM`, and if not, treat it like `NOSYS`.
+        if backend::fs::syscalls::is_statx_available() {
+            STATX_STATE.store(2, Ordering::Relaxed);
+            Err(io::Errno::PERM)
+        } else {
+            statx_error_nosys()
+        }
+    }
+}
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