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diff --git a/third_party/rust/rustix/README.md b/third_party/rust/rustix/README.md new file mode 100644 index 0000000000..9f437b1a4a --- /dev/null +++ b/third_party/rust/rustix/README.md @@ -0,0 +1,196 @@ +<div align="center"> + <h1><code>rustix</code></h1> + + <p> + <strong>Safe Rust bindings to POSIX/Unix/Linux/Winsock syscalls</strong> + </p> + + <strong>A <a href="https://bytecodealliance.org/">Bytecode Alliance</a> project</strong> + + <p> + <a href="https://github.com/bytecodealliance/rustix/actions?query=workflow%3ACI"><img src="https://github.com/bytecodealliance/rustix/workflows/CI/badge.svg" alt="Github Actions CI Status" /></a> + <a href="https://bytecodealliance.zulipchat.com/#narrow/stream/206238-general"><img src="https://img.shields.io/badge/zulip-join_chat-brightgreen.svg" alt="zulip chat" /></a> + <a href="https://crates.io/crates/rustix"><img src="https://img.shields.io/crates/v/rustix.svg" alt="crates.io page" /></a> + <a href="https://docs.rs/rustix"><img src="https://docs.rs/rustix/badge.svg" alt="docs.rs docs" /></a> + </p> +</div> + +`rustix` provides efficient memory-safe and [I/O-safe] wrappers to POSIX-like, +Unix-like, Linux, and Winsock syscall-like APIs, with configurable backends. +It uses Rust references, slices, and return values instead of raw pointers, and +[I/O safety types] instead of raw file descriptors, providing memory safety, +[I/O safety], and [provenance]. It uses `Result`s for reporting errors, +[`bitflags`] instead of bare integer flags, an [`Arg`] trait with optimizations +to efficiently accept any Rust string type, and several other efficient +conveniences. + +`rustix` is low-level and, and while the `net` API supports [Windows Sockets 2] +(Winsock), the rest of the APIs do not support Windows; for higher-level and +more portable APIs built on this functionality, see the [`cap-std`], [`memfd`], +[`timerfd`], and [`io-streams`] crates, for example. + +`rustix` currently has two backends available: + + * linux_raw, which uses raw Linux system calls and vDSO calls, and is + supported on Linux on x86-64, x86, aarch64, riscv64gc, powerpc64le, + arm (v5 onwards), mipsel, and mips64el, with stable, nightly, and 1.63 Rust. + - By being implemented entirely in Rust, avoiding `libc`, `errno`, and pthread + cancellation, and employing some specialized optimizations, most functions + compile down to very efficient code, which can often be fully inlined into + user code. + - Most functions in `linux_raw` preserve memory, I/O safety, and pointer + provenance all the way down to the syscalls. + + * libc, which uses the [`libc`] crate which provides bindings to native `libc` + libraries on Unix-family platforms, and [`windows-sys`] for Winsock on + Windows, and is portable to many OS's. + +The linux_raw backend is enabled by default on platforms which support it. To +enable the libc backend instead, either enable the "use-libc" cargo feature, +or set the `RUSTFLAGS` environment variable to `--cfg=rustix_use_libc` when +building. + +## Cargo features + +The modules [`rustix::io`], [`rustix::fd`], and [`rustix::ffi`] are enabled +by default. The rest of the API is conditional with cargo feature flags: + +| Name | Description | +| ---------- | -------------------------------------------------------------- | +| `event` | [`rustix::event`]—Polling and event operations. | +| `fs` | [`rustix::fs`]—Filesystem operations. | +| `io_uring` | [`rustix::io_uring`]—Linux io_uring. | +| `mm` | [`rustix::mm`]—Memory map operations. | +| `mount` | [`rustix::mount`]—Linux mount API. | +| `net` | [`rustix::net`]—Network-related operations. | +| `param` | [`rustix::param`]—Process parameters. | +| `pipe` | [`rustix::pipe`]—Pipe operations. | +| `process` | [`rustix::process`]—Process-associated operations. | +| `procfs` | [`rustix::procfs`]—Utilities for reading `/proc` on Linux. | +| `pty` | [`rustix::pty`]—Pseudoterminal operations. | +| `rand` | [`rustix::rand`]—Random-related operations. | +| `shm` | [`rustix::shm`]—POSIX shared memory. | +| `stdio` | [`rustix::stdio`]—Stdio-related operations. | +| `system` | [`rustix::system`]—System-related operations. | +| `termios` | [`rustix::termios`]—Terminal I/O stream operations. | +| `thread` | [`rustix::thread`]—Thread-associated operations. | +| `time` | [`rustix::time`]—Time-related operations. | +| | | +| `use-libc` | Enable the libc backend. | + +[`rustix::event`]: https://docs.rs/rustix/*/rustix/event/index.html +[`rustix::fs`]: https://docs.rs/rustix/*/rustix/fs/index.html +[`rustix::io_uring`]: https://docs.rs/rustix/*/rustix/io_uring/index.html +[`rustix::mm`]: https://docs.rs/rustix/*/rustix/mm/index.html +[`rustix::mount`]: https://docs.rs/rustix/*/rustix/mount/index.html +[`rustix::net`]: https://docs.rs/rustix/*/rustix/net/index.html +[`rustix::param`]: https://docs.rs/rustix/*/rustix/param/index.html +[`rustix::pipe`]: https://docs.rs/rustix/*/rustix/pipe/index.html +[`rustix::process`]: https://docs.rs/rustix/*/rustix/process/index.html +[`rustix::procfs`]: https://docs.rs/rustix/*/rustix/procfs/index.html +[`rustix::pty`]: https://docs.rs/rustix/*/rustix/pty/index.html +[`rustix::rand`]: https://docs.rs/rustix/*/rustix/rand/index.html +[`rustix::shm`]: https://docs.rs/rustix/*/rustix/shm/index.html +[`rustix::stdio`]: https://docs.rs/rustix/*/rustix/stdio/index.html +[`rustix::system`]: https://docs.rs/rustix/*/rustix/system/index.html +[`rustix::termios`]: https://docs.rs/rustix/*/rustix/termios/index.html +[`rustix::thread`]: https://docs.rs/rustix/*/rustix/thread/index.html +[`rustix::time`]: https://docs.rs/rustix/*/rustix/time/index.html +[`rustix::io`]: https://docs.rs/rustix/*/rustix/io/index.html +[`rustix::fd`]: https://docs.rs/rustix/*/rustix/fd/index.html +[`rustix::ffi`]: https://docs.rs/rustix/*/rustix/ffi/index.html + +## 64-bit Large File Support (LFS) and Year 2038 (y2038) support + +`rustix` automatically uses 64-bit APIs when available, and avoids exposing +32-bit APIs that would have the year-2038 problem or fail to support large +files. For instance, `rustix::fstatvfs` calls `fstatvfs64`, and returns a +struct that's 64-bit even on 32-bit platforms. + +## Similar crates + +`rustix` is similar to [`nix`], [`simple_libc`], [`unix`], [`nc`], [`uapi`], +and [`rusl`]. `rustix` is architected for [I/O safety] with most APIs using +[`OwnedFd`] and [`AsFd`] to manipulate file descriptors rather than `File` or +even `c_int`, and supporting multiple backends so that it can use direct +syscalls while still being usable on all platforms `libc` supports. Like `nix`, +`rustix` has an optimized and flexible filename argument mechanism that allows +users to use a variety of string types, including non-UTF-8 string types. + +[`relibc`] is a similar project which aims to be a full "libc", including +C-compatible interfaces and higher-level C/POSIX standard-library +functionality; `rustix` just aims to provide safe and idiomatic Rust interfaces +to low-level syscalls. `relibc` also doesn't tend to support features not +supported on Redox, such as `*at` functions like `openat`, which are important +features for `rustix`. + +`rustix` has its own code for making direct syscalls, similar to the +[`syscall`], [`sc`], and [`scall`] crates, using the Rust `asm!` macro. +`rustix` can also use Linux's vDSO mechanism to optimize Linux `clock_gettime` +on all architectures, and all Linux system calls on x86. And `rustix`'s +syscalls report errors using an optimized `Errno` type. + +`rustix`'s `*at` functions are similar to the [`openat`] crate, but `rustix` +provides them as free functions rather than associated functions of a `Dir` +type. `rustix`'s `CWD` constant exposes the special `AT_FDCWD` value in a safe +way, so users don't need to open `.` to get a current-directory handle. + +`rustix`'s `openat2` function is similar to the [`openat2`] crate, but uses I/O +safety types rather than `RawFd`. `rustix` does not provide dynamic feature +detection, so users must handle the [`NOSYS`] error themselves. + +`rustix`'s `termios` module is similar to the [`termios`] crate, but uses I/O +safety types rather than `RawFd`, and the flags parameters to functions such as +`tcsetattr` are `enum`s rather than bare integers. And, rustix calls its +`tcgetattr` function `tcgetattr`, rather than `Termios::from_fd`. + +## Minimum Supported Rust Version (MSRV) + +This crate currently works on the version of [Rust on Debian stable], which is +currently [Rust 1.63]. This policy may change in the future, in minor version +releases, so users using a fixed version of Rust should pin to a specific +version of this crate. + +## Minimum Linux Version + +On Linux platforms, rustix requires at least Linux 3.2. This is at most the +oldest Linux version supported by: + - [any current Rust target], or + - [kernel.org] at the time of rustix's [MSRV] release. +The specifics of this policy may change in the future, but we intend it to +always reflect “very old” Linux versions. + +[MSRV]: #minimum-supported-rust-version-msrv +[Rust 1.63]: https://blog.rust-lang.org/2022/08/11/Rust-1.63.0.html +[any current Rust target]: https://doc.rust-lang.org/nightly/rustc/platform-support.html +[kernel.org]: https://www.kernel.org/releases.html +[Rust on Debian stable]: https://packages.debian.org/stable/rust/rustc +[Windows Sockets 2]: https://learn.microsoft.com/en-us/windows/win32/winsock/windows-sockets-start-page-2 +[`nix`]: https://crates.io/crates/nix +[`unix`]: https://crates.io/crates/unix +[`nc`]: https://crates.io/crates/nc +[`simple_libc`]: https://crates.io/crates/simple_libc +[`uapi`]: https://crates.io/crates/uapi +[`rusl`]: https://lib.rs/crates/rusl +[`relibc`]: https://gitlab.redox-os.org/redox-os/relibc +[`syscall`]: https://crates.io/crates/syscall +[`sc`]: https://crates.io/crates/sc +[`scall`]: https://crates.io/crates/scall +[`openat`]: https://crates.io/crates/openat +[`openat2`]: https://crates.io/crates/openat2 +[I/O safety types]: https://doc.rust-lang.org/stable/std/os/fd/index.html#structs +[`termios`]: https://crates.io/crates/termios +[`libc`]: https://crates.io/crates/libc +[`windows-sys`]: https://crates.io/crates/windows-sys +[`cap-std`]: https://crates.io/crates/cap-std +[`memfd`]: https://crates.io/crates/memfd +[`timerfd`]: https://crates.io/crates/timerfd +[`io-streams`]: https://crates.io/crates/io-streams +[`bitflags`]: https://crates.io/crates/bitflags +[`Arg`]: https://docs.rs/rustix/*/rustix/path/trait.Arg.html +[I/O-safe]: https://github.com/rust-lang/rfcs/blob/master/text/3128-io-safety.md +[I/O safety]: https://github.com/rust-lang/rfcs/blob/master/text/3128-io-safety.md +[provenance]: https://github.com/rust-lang/rust/issues/95228 +[`OwnedFd`]: https://doc.rust-lang.org/stable/std/os/fd/struct.OwnedFd.html +[`AsFd`]: https://doc.rust-lang.org/stable/std/os/fd/trait.AsFd.html +[`NOSYS`]: https://docs.rs/rustix/*/rustix/io/struct.Errno.html#associatedconstant.NOSYS |