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//! `pipe` and related APIs.
//!
//! # Safety
//!
//! `vmsplice` is an unsafe function.
#![allow(unsafe_code)]
use crate::fd::OwnedFd;
use crate::{backend, io};
#[cfg(not(any(
solarish,
windows,
target_os = "espidf",
target_os = "haiku",
target_os = "redox",
target_os = "vita",
target_os = "wasi",
)))]
use backend::c;
#[cfg(linux_kernel)]
use backend::fd::AsFd;
#[cfg(not(apple))]
pub use backend::pipe::types::PipeFlags;
#[cfg(linux_kernel)]
pub use backend::pipe::types::{IoSliceRaw, SpliceFlags};
/// `PIPE_BUF`—The maximum length at which writes to a pipe are atomic.
///
/// # References
/// - [Linux]
/// - [POSIX]
///
#[cfg(not(any(
solarish,
windows,
target_os = "espidf",
target_os = "haiku",
target_os = "hurd",
target_os = "redox",
target_os = "vita",
target_os = "wasi",
)))]
pub const PIPE_BUF: usize = c::PIPE_BUF;
/// `pipe()`—Creates a pipe.
///
/// This function creates a pipe and returns two file descriptors, for the
/// reading and writing ends of the pipe, respectively.
///
/// # References
/// - [POSIX]
/// - [Linux]
/// - [Apple]
/// - [FreeBSD]
/// - [NetBSD]
/// - [OpenBSD]
/// - [DragonFly BSD]
/// - [illumos]
/// - [glibc]
///
/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/pipe.2.html
#[inline]
pub fn pipe() -> io::Result<(OwnedFd, OwnedFd)> {
backend::pipe::syscalls::pipe()
}
/// `pipe2(flags)`—Creates a pipe, with flags.
///
/// This function creates a pipe and returns two file descriptors, for the
/// reading and writing ends of the pipe, respectively.
///
/// # References
/// - [Linux]
/// - [FreeBSD]
/// - [NetBSD]
/// - [OpenBSD]
/// - [DragonFly BSD]
/// - [illumos]
///
#[cfg(not(any(
apple,
target_os = "aix",
target_os = "espidf",
target_os = "haiku",
target_os = "nto"
)))]
#[inline]
#[doc(alias = "pipe2")]
pub fn pipe_with(flags: PipeFlags) -> io::Result<(OwnedFd, OwnedFd)> {
backend::pipe::syscalls::pipe_with(flags)
}
/// `splice(fd_in, off_in, fd_out, off_out, len, flags)`—Transfer data
/// between a file and a pipe.
///
/// This function transfers up to `len` bytes of data from the file descriptor
/// `fd_in` to the file descriptor `fd_out`, where one of the file descriptors
/// must refer to a pipe.
///
/// `off_*` must be `None` if the corresponding fd refers to a pipe. Otherwise
/// its value points to the starting offset to the file, from which the data is
/// read/written. On success, the number of bytes read/written is added to the
/// offset.
///
/// Passing `None` causes the read/write to start from the file offset, and the
/// file offset is adjusted appropriately.
///
/// # References
/// - [Linux]
///
#[cfg(linux_kernel)]
#[inline]
pub fn splice<FdIn: AsFd, FdOut: AsFd>(
fd_in: FdIn,
off_in: Option<&mut u64>,
fd_out: FdOut,
off_out: Option<&mut u64>,
len: usize,
flags: SpliceFlags,
) -> io::Result<usize> {
backend::pipe::syscalls::splice(fd_in.as_fd(), off_in, fd_out.as_fd(), off_out, len, flags)
}
/// `vmsplice(fd, bufs, flags)`—Transfer data between memory and a pipe.
///
/// If `fd` is the write end of the pipe, the function maps the memory pointer
/// at by `bufs` to the pipe.
///
/// If `fd` is the read end of the pipe, the function writes data from the pipe
/// to said memory.
///
/// # Safety
///
/// If the memory must not be mutated (such as when `bufs` were originally
/// immutable slices), it is up to the caller to ensure that the write end of
/// the pipe is placed in `fd`.
///
/// Additionally if `SpliceFlags::GIFT` is set, the caller must also ensure
/// that the contents of `bufs` in never modified following the call, and that
/// all of the pointers in `bufs` are page aligned, and the lengths are
/// multiples of a page size in bytes.
///
/// # References
/// - [Linux]
///
#[cfg(linux_kernel)]
#[inline]
pub unsafe fn vmsplice<PipeFd: AsFd>(
fd: PipeFd,
bufs: &[IoSliceRaw<'_>],
flags: SpliceFlags,
) -> io::Result<usize> {
backend::pipe::syscalls::vmsplice(fd.as_fd(), bufs, flags)
}
/// `tee(fd_in, fd_out, len, flags)`—Copy data between pipes without
/// consuming it.
///
/// This reads up to `len` bytes from `in_fd` without consuming them, and
/// writes them to `out_fd`.
///
/// # References
/// - [Linux]
///
#[cfg(linux_kernel)]
#[inline]
pub fn tee<FdIn: AsFd, FdOut: AsFd>(
fd_in: FdIn,
fd_out: FdOut,
len: usize,
flags: SpliceFlags,
) -> io::Result<usize> {
backend::pipe::syscalls::tee(fd_in.as_fd(), fd_out.as_fd(), len, flags)
}
/// `fnctl(fd, F_GETPIPE_SZ)`—Return the buffer capacity of a pipe.
///
/// # References
/// - [Linux]
///
#[cfg(linux_kernel)]
#[inline]
pub fn fcntl_getpipe_size<Fd: AsFd>(fd: Fd) -> io::Result<usize> {
backend::pipe::syscalls::fcntl_getpipe_sz(fd.as_fd())
}
/// `fnctl(fd, F_SETPIPE_SZ)`—Set the buffer capacity of a pipe.
///
/// # References
/// - [Linux]
///
#[cfg(linux_kernel)]
#[inline]
pub fn fcntl_setpipe_size<Fd: AsFd>(fd: Fd, size: usize) -> io::Result<()> {
backend::pipe::syscalls::fcntl_setpipe_sz(fd.as_fd(), size)
}