215 lines
7 KiB
Rust
215 lines
7 KiB
Rust
//! The libc backend.
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//!
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//! On most platforms, this uses the `libc` crate to make system calls. On
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//! Windows, this uses the Winsock API in `windows-sys`, which can be adapted
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//! to have a very `libc`-like interface.
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// Every FFI call requires an unsafe block, and there are a lot of FFI
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// calls. For now, set this to allow for the libc backend.
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#![allow(clippy::undocumented_unsafe_blocks)]
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// Lots of libc types vary between platforms, so we often need a `.into()` on
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// one platform where it's redundant on another.
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#![allow(clippy::useless_conversion)]
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mod conv;
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#[cfg(windows)]
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pub(crate) mod fd {
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pub use crate::maybe_polyfill::os::windows::io::{
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AsRawSocket, AsSocket, BorrowedSocket as BorrowedFd, FromRawSocket, IntoRawSocket,
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OwnedSocket as OwnedFd, RawSocket as RawFd,
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};
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pub(crate) use windows_sys::Win32::Networking::WinSock::SOCKET as LibcFd;
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/// A version of [`AsRawFd`] for use with Winsock API.
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///
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/// [`AsRawFd`]: https://doc.rust-lang.org/stable/std/os/fd/trait.AsRawFd.html
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pub trait AsRawFd {
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/// A version of [`as_raw_fd`] for use with Winsock API.
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///
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/// [`as_raw_fd`]: https://doc.rust-lang.org/stable/std/os/fd/trait.FromRawFd.html#tymethod.as_raw_fd
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fn as_raw_fd(&self) -> RawFd;
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}
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impl<T: AsRawSocket> AsRawFd for T {
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#[inline]
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fn as_raw_fd(&self) -> RawFd {
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self.as_raw_socket()
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}
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}
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/// A version of [`IntoRawFd`] for use with Winsock API.
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///
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/// [`IntoRawFd`]: https://doc.rust-lang.org/stable/std/os/fd/trait.IntoRawFd.html
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pub trait IntoRawFd {
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/// A version of [`into_raw_fd`] for use with Winsock API.
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///
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/// [`into_raw_fd`]: https://doc.rust-lang.org/stable/std/os/fd/trait.FromRawFd.html#tymethod.into_raw_fd
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fn into_raw_fd(self) -> RawFd;
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}
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impl<T: IntoRawSocket> IntoRawFd for T {
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#[inline]
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fn into_raw_fd(self) -> RawFd {
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self.into_raw_socket()
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}
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}
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/// A version of [`FromRawFd`] for use with Winsock API.
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///
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/// [`FromRawFd`]: https://doc.rust-lang.org/stable/std/os/fd/trait.FromRawFd.html
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pub trait FromRawFd {
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/// A version of [`from_raw_fd`] for use with Winsock API.
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///
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/// # Safety
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///
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/// See the [safety requirements] for [`from_raw_fd`].
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///
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/// [`from_raw_fd`]: https://doc.rust-lang.org/stable/std/os/fd/trait.FromRawFd.html#tymethod.from_raw_fd
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/// [safety requirements]: https://doc.rust-lang.org/stable/std/os/fd/trait.FromRawFd.html#safety
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unsafe fn from_raw_fd(raw_fd: RawFd) -> Self;
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}
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impl<T: FromRawSocket> FromRawFd for T {
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#[inline]
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unsafe fn from_raw_fd(raw_fd: RawFd) -> Self {
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Self::from_raw_socket(raw_fd)
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}
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}
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/// A version of [`AsFd`] for use with Winsock API.
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///
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/// [`AsFd`]: https://doc.rust-lang.org/stable/std/os/fd/trait.AsFd.html
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pub trait AsFd {
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/// An `as_fd` function for Winsock, where a `Fd` is a `Socket`.
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fn as_fd(&self) -> BorrowedFd;
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}
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impl<T: AsSocket> AsFd for T {
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#[inline]
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fn as_fd(&self) -> BorrowedFd {
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self.as_socket()
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}
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}
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}
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#[cfg(not(windows))]
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pub(crate) mod fd {
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pub use crate::maybe_polyfill::os::fd::{
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AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd,
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};
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#[allow(unused_imports)]
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pub(crate) use RawFd as LibcFd;
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}
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// On Windows we emulate selected libc-compatible interfaces. On non-Windows,
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// we just use libc here, since this is the libc backend.
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#[cfg_attr(windows, path = "winsock_c.rs")]
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pub(crate) mod c;
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#[cfg(feature = "event")]
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pub(crate) mod event;
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#[cfg(not(windows))]
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#[cfg(feature = "fs")]
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pub(crate) mod fs;
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pub(crate) mod io;
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#[cfg(linux_kernel)]
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#[cfg(feature = "io_uring")]
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pub(crate) mod io_uring;
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#[cfg(not(any(windows, target_os = "espidf", target_os = "vita", target_os = "wasi")))]
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#[cfg(feature = "mm")]
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pub(crate) mod mm;
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#[cfg(linux_kernel)]
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#[cfg(feature = "mount")]
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pub(crate) mod mount;
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#[cfg(linux_kernel)]
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#[cfg(all(feature = "fs", not(feature = "mount")))]
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pub(crate) mod mount; // for deprecated mount functions in "fs"
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#[cfg(not(any(target_os = "redox", target_os = "wasi")))]
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#[cfg(feature = "net")]
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pub(crate) mod net;
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#[cfg(not(any(windows, target_os = "espidf")))]
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#[cfg(any(
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feature = "param",
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feature = "runtime",
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feature = "time",
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target_arch = "x86",
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))]
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pub(crate) mod param;
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#[cfg(not(windows))]
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#[cfg(feature = "pipe")]
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pub(crate) mod pipe;
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#[cfg(not(windows))]
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#[cfg(feature = "process")]
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pub(crate) mod process;
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#[cfg(not(windows))]
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#[cfg(not(target_os = "wasi"))]
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#[cfg(feature = "pty")]
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pub(crate) mod pty;
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#[cfg(not(windows))]
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#[cfg(feature = "rand")]
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pub(crate) mod rand;
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#[cfg(not(windows))]
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#[cfg(not(target_os = "wasi"))]
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#[cfg(feature = "system")]
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pub(crate) mod system;
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#[cfg(not(any(windows, target_os = "vita")))]
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#[cfg(feature = "termios")]
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pub(crate) mod termios;
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#[cfg(not(windows))]
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#[cfg(feature = "thread")]
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pub(crate) mod thread;
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#[cfg(not(any(windows, target_os = "espidf")))]
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#[cfg(feature = "time")]
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pub(crate) mod time;
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/// If the host libc is glibc, return `true` if it is less than version 2.25.
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///
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/// To restate and clarify, this function returning true does not mean the libc
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/// is glibc just that if it is glibc, it is less than version 2.25.
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///
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/// For now, this function is only available on Linux, but if it ends up being
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/// used beyond that, this could be changed to e.g. `#[cfg(unix)]`.
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#[cfg(all(unix, target_env = "gnu"))]
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pub(crate) fn if_glibc_is_less_than_2_25() -> bool {
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// This is also defined inside `weak_or_syscall!` in
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// backend/libc/rand/syscalls.rs, but it's not convenient to re-export the
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// weak symbol from that macro, so we duplicate it at a small cost here.
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weak! { fn getrandom(*mut c::c_void, c::size_t, c::c_uint) -> c::ssize_t }
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// glibc 2.25 has `getrandom`, which is how we satisfy the API contract of
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// this function. But, there are likely other libc versions which have it.
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getrandom.get().is_none()
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}
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// Private modules used by multiple public modules.
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#[cfg(any(feature = "procfs", feature = "process", feature = "runtime"))]
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#[cfg(not(any(windows, target_os = "wasi")))]
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pub(crate) mod pid;
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#[cfg(any(feature = "process", feature = "thread"))]
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#[cfg(linux_kernel)]
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pub(crate) mod prctl;
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#[cfg(not(any(
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windows,
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target_os = "android",
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target_os = "espidf",
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target_os = "vita",
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target_os = "wasi"
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)))]
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#[cfg(feature = "shm")]
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pub(crate) mod shm;
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#[cfg(any(feature = "fs", feature = "thread", feature = "process"))]
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#[cfg(not(any(windows, target_os = "wasi")))]
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pub(crate) mod ugid;
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#[cfg(bsd)]
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const MAX_IOV: usize = c::IOV_MAX as usize;
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#[cfg(any(linux_kernel, target_os = "emscripten", target_os = "nto"))]
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const MAX_IOV: usize = c::UIO_MAXIOV as usize;
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#[cfg(not(any(
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bsd,
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linux_kernel,
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windows,
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target_os = "emscripten",
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target_os = "espidf",
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target_os = "nto",
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target_os = "horizon",
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)))]
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const MAX_IOV: usize = 16; // The minimum value required by POSIX.
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