vendor/rustix-0.37.22/src/fs/fd.rs - toolchain/rustc - Git at Google

 //! Functions which operate on file descriptors.

 #[cfg(not(target_os = "wasi"))]
 use crate::fs::Mode;
 use crate::fs::{OFlags, Timespec};
 use crate::io::SeekFrom;
 #[cfg(not(target_os = "wasi"))]
 use crate::process::{Gid, Uid};
 use crate::{backend, io};
 use backend::fd::{AsFd, BorrowedFd};

 #[cfg(not(target_os = "wasi"))]
 pub use backend::fs::types::FlockOperation;

 #[cfg(not(any(
     netbsdlike,
     solarish,
     target_os = "aix",
     target_os = "dragonfly",
     target_os = "redox",
 )))]
 pub use backend::fs::types::FallocateFlags;

 pub use backend::fs::types::Stat;

 #[cfg(not(any(
     solarish,
     target_os = "haiku",
     target_os = "netbsd",
     target_os = "redox",
     target_os = "wasi",
 )))]
 pub use backend::fs::types::StatFs;

 #[cfg(not(any(target_os = "haiku", target_os = "redox", target_os = "wasi")))]
 pub use backend::fs::types::{StatVfs, StatVfsMountFlags};

 #[cfg(linux_kernel)]
 pub use backend::fs::types::FsWord;

 /// Timestamps used by [`utimensat`] and [`futimens`].
 ///
 /// [`utimensat`]: crate::fs::utimensat
 /// [`futimens`]: crate::fs::futimens
 // This is `repr(C)` and specifically laid out to match the representation used
 // by `utimensat` and `futimens`, which expect 2-element arrays of timestamps.
 #[repr(C)]
 #[derive(Clone, Debug)]
 pub struct Timestamps {
     /// The timestamp of the last access to a filesystem object.
     pub last_access: Timespec,

     /// The timestamp of the last modification of a filesystem object.
     pub last_modification: Timespec,
 }

 /// The filesystem magic number for procfs.
 ///
 /// See [the `fstatfs` manual page] for more information.
 ///
 /// [the `fstatfs` manual page]: https://man7.org/linux/man-pages/man2/fstatfs.2.html#DESCRIPTION
 #[cfg(linux_kernel)]
 pub const PROC_SUPER_MAGIC: FsWord = backend::c::PROC_SUPER_MAGIC as FsWord;

 /// The filesystem magic number for NFS.
 ///
 /// See [the `fstatfs` manual page] for more information.
 ///
 /// [the `fstatfs` manual page]: https://man7.org/linux/man-pages/man2/fstatfs.2.html#DESCRIPTION
 #[cfg(linux_kernel)]
 pub const NFS_SUPER_MAGIC: FsWord = backend::c::NFS_SUPER_MAGIC as FsWord;

 /// `lseek(fd, offset, whence)`—Repositions a file descriptor within a file.
 ///
 /// # References
 ///  - [POSIX]
 ///  - [Linux]
 ///
 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/lseek.html
 /// [Linux]: https://man7.org/linux/man-pages/man2/lseek.2.html
 #[inline]
 #[doc(alias = "lseek")]
 pub fn seek<Fd: AsFd>(fd: Fd, pos: SeekFrom) -> io::Result<u64> {
     backend::fs::syscalls::seek(fd.as_fd(), pos)
 }

 /// `lseek(fd, 0, SEEK_CUR)`—Returns the current position within a file.
 ///
 /// Return the current position of the file descriptor. This is a subset of
 /// the functionality of `seek`, but this interface makes it easier for users
 /// to declare their intent not to mutate any state.
 ///
 /// # References
 ///  - [POSIX]
 ///  - [Linux]
 ///
 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/lseek.html
 /// [Linux]: https://man7.org/linux/man-pages/man2/lseek.2.html
 #[inline]
 #[doc(alias = "lseek")]
 pub fn tell<Fd: AsFd>(fd: Fd) -> io::Result<u64> {
     backend::fs::syscalls::tell(fd.as_fd())
 }

 /// `fchmod(fd)`—Sets open file or directory permissions.
 ///
 /// This implementation does not support `O_PATH` file descriptors, even on
 /// platforms where the host libc emulates it.
 ///
 /// # References
 ///  - [POSIX]
 ///  - [Linux]
 ///
 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fchmod.html
 /// [Linux]: https://man7.org/linux/man-pages/man2/fchmod.2.html
 #[cfg(not(target_os = "wasi"))]
 #[inline]
 pub fn fchmod<Fd: AsFd>(fd: Fd, mode: Mode) -> io::Result<()> {
     backend::fs::syscalls::fchmod(fd.as_fd(), mode)
 }

 /// `fchown(fd)`—Sets open file or directory ownership.
 ///
 /// # References
 ///  - [POSIX]
 ///  - [Linux]
 ///
 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fchown.html
 /// [Linux]: https://man7.org/linux/man-pages/man2/fchown.2.html
 #[cfg(not(target_os = "wasi"))]
 #[inline]
 pub fn fchown<Fd: AsFd>(fd: Fd, owner: Option<Uid>, group: Option<Gid>) -> io::Result<()> {
     backend::fs::syscalls::fchown(fd.as_fd(), owner, group)
 }

 /// `fstat(fd)`—Queries metadata for an open file or directory.
 ///
 /// [`Mode::from_raw_mode`] and [`FileType::from_raw_mode`] may be used to
 /// interpret the `st_mode` field.
 ///
 /// # References
 ///  - [POSIX]
 ///  - [Linux]
 ///
 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fstat.html
 /// [Linux]: https://man7.org/linux/man-pages/man2/fstat.2.html
 /// [`Mode::from_raw_mode`]: Mode::from_raw_mode
 /// [`FileType::from_raw_mode`]: crate::fs::FileType::from_raw_mode
 #[inline]
 pub fn fstat<Fd: AsFd>(fd: Fd) -> io::Result<Stat> {
     backend::fs::syscalls::fstat(fd.as_fd())
 }

 /// `fstatfs(fd)`—Queries filesystem statistics for an open file or directory.
 ///
 /// Compared to [`fstatvfs`], this function often provides more information,
 /// though it's less portable.
 ///
 /// # References
 ///  - [Linux]
 ///
 /// [Linux]: https://man7.org/linux/man-pages/man2/fstatfs.2.html
 #[cfg(not(any(
     solarish,
     target_os = "haiku",
     target_os = "netbsd",
     target_os = "redox",
     target_os = "wasi",
 )))]
 #[inline]
 pub fn fstatfs<Fd: AsFd>(fd: Fd) -> io::Result<StatFs> {
     backend::fs::syscalls::fstatfs(fd.as_fd())
 }

 /// `fstatvfs(fd)`—Queries filesystem statistics for an open file or
 /// directory, POSIX version.
 ///
 /// Compared to [`fstatfs`], this function often provides less information,
 /// but it is more portable. But even so, filesystems are very diverse and not
 /// all the fields are meaningful for every filesystem. And `f_fsid` doesn't
 /// seem to have a clear meaning anywhere.
 ///
 /// # References
 ///  - [POSIX]
 ///  - [Linux]
 ///
 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fstatvfs.html
 /// [Linux]: https://man7.org/linux/man-pages/man2/fstatvfs.2.html
 #[cfg(not(any(target_os = "haiku", target_os = "redox", target_os = "wasi")))]
 #[inline]
 pub fn fstatvfs<Fd: AsFd>(fd: Fd) -> io::Result<StatVfs> {
     backend::fs::syscalls::fstatvfs(fd.as_fd())
 }

 /// `futimens(fd, times)`—Sets timestamps for an open file or directory.
 ///
 /// # References
 ///  - [POSIX]
 ///  - [Linux]
 ///
 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/futimens.html
 /// [Linux]: https://man7.org/linux/man-pages/man2/utimensat.2.html
 #[inline]
 pub fn futimens<Fd: AsFd>(fd: Fd, times: &Timestamps) -> io::Result<()> {
     backend::fs::syscalls::futimens(fd.as_fd(), times)
 }

 /// `fallocate(fd, mode, offset, len)`—Adjusts file allocation.
 ///
 /// This is a more general form of `posix_fallocate`, adding a `mode` argument
 /// which modifies the behavior. On platforms which only support
 /// `posix_fallocate` and not the more general form, no `FallocateFlags` values
 /// are defined so it will always be empty.
 ///
 /// # References
 ///  - [POSIX]
 ///  - [Linux `fallocate`]
 ///  - [Linux `posix_fallocate`]
 ///
 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_fallocate.html
 /// [Linux `fallocate`]: https://man7.org/linux/man-pages/man2/fallocate.2.html
 /// [Linux `posix_fallocate`]: https://man7.org/linux/man-pages/man3/posix_fallocate.3.html
 #[cfg(not(any(
     netbsdlike,
     solarish,
     target_os = "aix",
     target_os = "dragonfly",
     target_os = "redox",
 )))] // not implemented in libc for netbsd yet
 #[inline]
 #[doc(alias = "posix_fallocate")]
 pub fn fallocate<Fd: AsFd>(fd: Fd, mode: FallocateFlags, offset: u64, len: u64) -> io::Result<()> {
     backend::fs::syscalls::fallocate(fd.as_fd(), mode, offset, len)
 }

 /// `fcntl(fd, F_GETFL) & O_ACCMODE`
 ///
 /// Returns a pair of booleans indicating whether the file descriptor is
 /// readable and/or writable, respectively. This is only reliable on files; for
 /// example, it doesn't reflect whether sockets have been shut down; for
 /// general I/O handle support, use [`io::is_read_write`].
 #[inline]
 pub fn is_file_read_write<Fd: AsFd>(fd: Fd) -> io::Result<(bool, bool)> {
     _is_file_read_write(fd.as_fd())
 }

 pub(crate) fn _is_file_read_write(fd: BorrowedFd<'_>) -> io::Result<(bool, bool)> {
     let mode = backend::fs::syscalls::fcntl_getfl(fd)?;

     // Check for `O_PATH`.
     #[cfg(any(linux_kernel, target_os = "fuchsia", target_os = "emscripten"))]
     if mode.contains(OFlags::PATH) {
         return Ok((false, false));
     }

     // Use `RWMODE` rather than `ACCMODE` as `ACCMODE` may include `O_PATH`.
     // We handled `O_PATH` above.
     match mode & OFlags::RWMODE {
         OFlags::RDONLY => Ok((true, false)),
         OFlags::RDWR => Ok((true, true)),
         OFlags::WRONLY => Ok((false, true)),
         _ => unreachable!(),
     }
 }

 /// `fsync(fd)`—Ensures that file data and metadata is written to the
 /// underlying storage device.
 ///
 /// On iOS and macOS this isn't sufficient to ensure that data has reached
 /// persistent storage; use [`fcntl_fullfsync`] to ensure that.
 ///
 /// # References
 ///  - [POSIX]
 ///  - [Linux]
 ///
 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fsync.html
 /// [Linux]: https://man7.org/linux/man-pages/man2/fsync.2.html
 /// [`fcntl_fullfsync`]: https://docs.rs/rustix/*/x86_64-apple-darwin/rustix/fs/fn.fcntl_fullfsync.html
 #[inline]
 pub fn fsync<Fd: AsFd>(fd: Fd) -> io::Result<()> {
     backend::fs::syscalls::fsync(fd.as_fd())
 }

 /// `fdatasync(fd)`—Ensures that file data is written to the underlying
 /// storage device.
 ///
 /// # References
 ///  - [POSIX]
 ///  - [Linux]
 ///
 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fdatasync.html
 /// [Linux]: https://man7.org/linux/man-pages/man2/fdatasync.2.html
 #[cfg(not(any(
     apple,
     target_os = "dragonfly",
     target_os = "haiku",
     target_os = "redox",
 )))]
 #[inline]
 pub fn fdatasync<Fd: AsFd>(fd: Fd) -> io::Result<()> {
     backend::fs::syscalls::fdatasync(fd.as_fd())
 }

 /// `ftruncate(fd, length)`—Sets the length of a file.
 ///
 /// # References
 ///  - [POSIX]
 ///  - [Linux]
 ///
 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html
 /// [Linux]: https://man7.org/linux/man-pages/man2/ftruncate.2.html
 #[inline]
 pub fn ftruncate<Fd: AsFd>(fd: Fd, length: u64) -> io::Result<()> {
     backend::fs::syscalls::ftruncate(fd.as_fd(), length)
 }

 /// `flock(fd, operation)`—Acquire or release an advisory lock on an open file.
 ///
 /// # References
 ///  - [Linux]
 ///
 /// [Linux]: https://man7.org/linux/man-pages/man2/flock.2.html
 #[cfg(not(any(target_os = "solaris", target_os = "wasi")))]
 #[inline]
 pub fn flock<Fd: AsFd>(fd: Fd, operation: FlockOperation) -> io::Result<()> {
     backend::fs::syscalls::flock(fd.as_fd(), operation)
 }

 /// `syncfs(fd)`—Flush cached filesystem data.
 ///
 /// # References
 ///  - [Linux]
 ///
 /// [Linux]: https://man7.org/linux/man-pages/man2/syncfs.2.html
 #[cfg(linux_kernel)]
 #[inline]
 pub fn syncfs<Fd: AsFd>(fd: Fd) -> io::Result<()> {
     backend::fs::syscalls::syncfs(fd.as_fd())
 }
	//! Functions which operate on file descriptors.

	#[cfg(not(target_os = "wasi"))]
	use crate::fs::Mode;
	use crate::fs::{OFlags, Timespec};
	use crate::io::SeekFrom;
	#[cfg(not(target_os = "wasi"))]
	use crate::process::{Gid, Uid};
	use crate::{backend, io};
	use backend::fd::{AsFd, BorrowedFd};

	#[cfg(not(target_os = "wasi"))]
	pub use backend::fs::types::FlockOperation;

	#[cfg(not(any(
	netbsdlike,
	solarish,
	target_os = "aix",
	target_os = "dragonfly",
	target_os = "redox",
	)))]
	pub use backend::fs::types::FallocateFlags;

	pub use backend::fs::types::Stat;

	#[cfg(not(any(
	solarish,
	target_os = "haiku",
	target_os = "netbsd",
	target_os = "redox",
	target_os = "wasi",
	)))]
	pub use backend::fs::types::StatFs;

	#[cfg(not(any(target_os = "haiku", target_os = "redox", target_os = "wasi")))]
	pub use backend::fs::types::{StatVfs, StatVfsMountFlags};

	#[cfg(linux_kernel)]
	pub use backend::fs::types::FsWord;

	/// Timestamps used by [`utimensat`] and [`futimens`].
	///
	/// [`utimensat`]: crate::fs::utimensat
	/// [`futimens`]: crate::fs::futimens
	// This is `repr(C)` and specifically laid out to match the representation used
	// by `utimensat` and `futimens`, which expect 2-element arrays of timestamps.
	#[repr(C)]
	#[derive(Clone, Debug)]
	pub struct Timestamps {
	/// The timestamp of the last access to a filesystem object.
	pub last_access: Timespec,

	/// The timestamp of the last modification of a filesystem object.
	pub last_modification: Timespec,
	}

	/// The filesystem magic number for procfs.
	///
	/// See [the `fstatfs` manual page] for more information.
	///
	/// [the `fstatfs` manual page]: https://man7.org/linux/man-pages/man2/fstatfs.2.html#DESCRIPTION
	#[cfg(linux_kernel)]
	pub const PROC_SUPER_MAGIC: FsWord = backend::c::PROC_SUPER_MAGIC as FsWord;

	/// The filesystem magic number for NFS.
	///
	/// See [the `fstatfs` manual page] for more information.
	///
	/// [the `fstatfs` manual page]: https://man7.org/linux/man-pages/man2/fstatfs.2.html#DESCRIPTION
	#[cfg(linux_kernel)]
	pub const NFS_SUPER_MAGIC: FsWord = backend::c::NFS_SUPER_MAGIC as FsWord;

	/// `lseek(fd, offset, whence)`—Repositions a file descriptor within a file.
	///
	/// # References
	/// - [POSIX]
	/// - [Linux]
	///
	/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/lseek.html
	/// [Linux]: https://man7.org/linux/man-pages/man2/lseek.2.html
	#[inline]
	#[doc(alias = "lseek")]
	pub fn seek<Fd: AsFd>(fd: Fd, pos: SeekFrom) -> io::Result<u64> {
	backend::fs::syscalls::seek(fd.as_fd(), pos)
	}

	/// `lseek(fd, 0, SEEK_CUR)`—Returns the current position within a file.
	///
	/// Return the current position of the file descriptor. This is a subset of
	/// the functionality of `seek`, but this interface makes it easier for users
	/// to declare their intent not to mutate any state.
	///
	/// # References
	/// - [POSIX]
	/// - [Linux]
	///
	/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/lseek.html
	/// [Linux]: https://man7.org/linux/man-pages/man2/lseek.2.html
	#[inline]
	#[doc(alias = "lseek")]
	pub fn tell<Fd: AsFd>(fd: Fd) -> io::Result<u64> {
	backend::fs::syscalls::tell(fd.as_fd())
	}

	/// `fchmod(fd)`—Sets open file or directory permissions.
	///
	/// This implementation does not support `O_PATH` file descriptors, even on
	/// platforms where the host libc emulates it.
	///
	/// # References
	/// - [POSIX]
	/// - [Linux]
	///
	/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fchmod.html
	/// [Linux]: https://man7.org/linux/man-pages/man2/fchmod.2.html
	#[cfg(not(target_os = "wasi"))]
	#[inline]
	pub fn fchmod<Fd: AsFd>(fd: Fd, mode: Mode) -> io::Result<()> {
	backend::fs::syscalls::fchmod(fd.as_fd(), mode)
	}

	/// `fchown(fd)`—Sets open file or directory ownership.
	///
	/// # References
	/// - [POSIX]
	/// - [Linux]
	///
	/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fchown.html
	/// [Linux]: https://man7.org/linux/man-pages/man2/fchown.2.html
	#[cfg(not(target_os = "wasi"))]
	#[inline]
	pub fn fchown<Fd: AsFd>(fd: Fd, owner: Option<Uid>, group: Option<Gid>) -> io::Result<()> {
	backend::fs::syscalls::fchown(fd.as_fd(), owner, group)
	}

	/// `fstat(fd)`—Queries metadata for an open file or directory.
	///
	/// [`Mode::from_raw_mode`] and [`FileType::from_raw_mode`] may be used to
	/// interpret the `st_mode` field.
	///
	/// # References
	/// - [POSIX]
	/// - [Linux]
	///
	/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fstat.html
	/// [Linux]: https://man7.org/linux/man-pages/man2/fstat.2.html
	/// [`Mode::from_raw_mode`]: Mode::from_raw_mode
	/// [`FileType::from_raw_mode`]: crate::fs::FileType::from_raw_mode
	#[inline]
	pub fn fstat<Fd: AsFd>(fd: Fd) -> io::Result<Stat> {
	backend::fs::syscalls::fstat(fd.as_fd())
	}

	/// `fstatfs(fd)`—Queries filesystem statistics for an open file or directory.
	///
	/// Compared to [`fstatvfs`], this function often provides more information,
	/// though it's less portable.
	///
	/// # References
	/// - [Linux]
	///
	/// [Linux]: https://man7.org/linux/man-pages/man2/fstatfs.2.html
	#[cfg(not(any(
	solarish,
	target_os = "haiku",
	target_os = "netbsd",
	target_os = "redox",
	target_os = "wasi",
	)))]
	#[inline]
	pub fn fstatfs<Fd: AsFd>(fd: Fd) -> io::Result<StatFs> {
	backend::fs::syscalls::fstatfs(fd.as_fd())
	}

	/// `fstatvfs(fd)`—Queries filesystem statistics for an open file or
	/// directory, POSIX version.
	///
	/// Compared to [`fstatfs`], this function often provides less information,
	/// but it is more portable. But even so, filesystems are very diverse and not
	/// all the fields are meaningful for every filesystem. And `f_fsid` doesn't
	/// seem to have a clear meaning anywhere.
	///
	/// # References
	/// - [POSIX]
	/// - [Linux]
	///
	/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fstatvfs.html
	/// [Linux]: https://man7.org/linux/man-pages/man2/fstatvfs.2.html
	#[cfg(not(any(target_os = "haiku", target_os = "redox", target_os = "wasi")))]
	#[inline]
	pub fn fstatvfs<Fd: AsFd>(fd: Fd) -> io::Result<StatVfs> {
	backend::fs::syscalls::fstatvfs(fd.as_fd())
	}

	/// `futimens(fd, times)`—Sets timestamps for an open file or directory.
	///
	/// # References
	/// - [POSIX]
	/// - [Linux]
	///
	/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/futimens.html
	/// [Linux]: https://man7.org/linux/man-pages/man2/utimensat.2.html
	#[inline]
	pub fn futimens<Fd: AsFd>(fd: Fd, times: &Timestamps) -> io::Result<()> {
	backend::fs::syscalls::futimens(fd.as_fd(), times)
	}

	/// `fallocate(fd, mode, offset, len)`—Adjusts file allocation.
	///
	/// This is a more general form of `posix_fallocate`, adding a `mode` argument
	/// which modifies the behavior. On platforms which only support
	/// `posix_fallocate` and not the more general form, no `FallocateFlags` values
	/// are defined so it will always be empty.
	///
	/// # References
	/// - [POSIX]
	/// - [Linux `fallocate`]
	/// - [Linux `posix_fallocate`]
	///
	/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_fallocate.html
	/// [Linux `fallocate`]: https://man7.org/linux/man-pages/man2/fallocate.2.html
	/// [Linux `posix_fallocate`]: https://man7.org/linux/man-pages/man3/posix_fallocate.3.html
	#[cfg(not(any(
	netbsdlike,
	solarish,
	target_os = "aix",
	target_os = "dragonfly",
	target_os = "redox",
	)))] // not implemented in libc for netbsd yet
	#[inline]
	#[doc(alias = "posix_fallocate")]
	pub fn fallocate<Fd: AsFd>(fd: Fd, mode: FallocateFlags, offset: u64, len: u64) -> io::Result<()> {
	backend::fs::syscalls::fallocate(fd.as_fd(), mode, offset, len)
	}

	/// `fcntl(fd, F_GETFL) & O_ACCMODE`
	///
	/// Returns a pair of booleans indicating whether the file descriptor is
	/// readable and/or writable, respectively. This is only reliable on files; for
	/// example, it doesn't reflect whether sockets have been shut down; for
	/// general I/O handle support, use [`io::is_read_write`].
	#[inline]
	pub fn is_file_read_write<Fd: AsFd>(fd: Fd) -> io::Result<(bool, bool)> {
	_is_file_read_write(fd.as_fd())
	}

	pub(crate) fn _is_file_read_write(fd: BorrowedFd<'_>) -> io::Result<(bool, bool)> {
	let mode = backend::fs::syscalls::fcntl_getfl(fd)?;

	// Check for `O_PATH`.
	#[cfg(any(linux_kernel, target_os = "fuchsia", target_os = "emscripten"))]
	if mode.contains(OFlags::PATH) {
	return Ok((false, false));
	}

	// Use `RWMODE` rather than `ACCMODE` as `ACCMODE` may include `O_PATH`.
	// We handled `O_PATH` above.
	match mode & OFlags::RWMODE {
	OFlags::RDONLY => Ok((true, false)),
	OFlags::RDWR => Ok((true, true)),
	OFlags::WRONLY => Ok((false, true)),
	_ => unreachable!(),
	}
	}

	/// `fsync(fd)`—Ensures that file data and metadata is written to the
	/// underlying storage device.
	///
	/// On iOS and macOS this isn't sufficient to ensure that data has reached
	/// persistent storage; use [`fcntl_fullfsync`] to ensure that.
	///
	/// # References
	/// - [POSIX]
	/// - [Linux]
	///
	/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fsync.html
	/// [Linux]: https://man7.org/linux/man-pages/man2/fsync.2.html
	/// [`fcntl_fullfsync`]: https://docs.rs/rustix/*/x86_64-apple-darwin/rustix/fs/fn.fcntl_fullfsync.html
	#[inline]
	pub fn fsync<Fd: AsFd>(fd: Fd) -> io::Result<()> {
	backend::fs::syscalls::fsync(fd.as_fd())
	}

	/// `fdatasync(fd)`—Ensures that file data is written to the underlying
	/// storage device.
	///
	/// # References
	/// - [POSIX]
	/// - [Linux]
	///
	/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fdatasync.html
	/// [Linux]: https://man7.org/linux/man-pages/man2/fdatasync.2.html
	#[cfg(not(any(
	apple,
	target_os = "dragonfly",
	target_os = "haiku",
	target_os = "redox",
	)))]
	#[inline]
	pub fn fdatasync<Fd: AsFd>(fd: Fd) -> io::Result<()> {
	backend::fs::syscalls::fdatasync(fd.as_fd())
	}

	/// `ftruncate(fd, length)`—Sets the length of a file.
	///
	/// # References
	/// - [POSIX]
	/// - [Linux]
	///
	/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html
	/// [Linux]: https://man7.org/linux/man-pages/man2/ftruncate.2.html
	#[inline]
	pub fn ftruncate<Fd: AsFd>(fd: Fd, length: u64) -> io::Result<()> {
	backend::fs::syscalls::ftruncate(fd.as_fd(), length)
	}

	/// `flock(fd, operation)`—Acquire or release an advisory lock on an open file.
	///
	/// # References
	/// - [Linux]
	///
	/// [Linux]: https://man7.org/linux/man-pages/man2/flock.2.html
	#[cfg(not(any(target_os = "solaris", target_os = "wasi")))]
	#[inline]
	pub fn flock<Fd: AsFd>(fd: Fd, operation: FlockOperation) -> io::Result<()> {
	backend::fs::syscalls::flock(fd.as_fd(), operation)
	}

	/// `syncfs(fd)`—Flush cached filesystem data.
	///
	/// # References
	/// - [Linux]
	///
	/// [Linux]: https://man7.org/linux/man-pages/man2/syncfs.2.html
	#[cfg(linux_kernel)]
	#[inline]
	pub fn syncfs<Fd: AsFd>(fd: Fd) -> io::Result<()> {
	backend::fs::syscalls::syncfs(fd.as_fd())
	}