rustix
Safe Rust bindings to POSIX/Unix/Linux/Winsock2 syscalls
A Bytecode Alliance project
rustix provides efficient memory-safe and [I/O-safe] wrappers to POSIX-like,
Unix-like, Linux, and Winsock2 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 Results 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 Winsock2 on
Windows, 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.
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.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 Winsock2 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.
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] and [rustix::path]—Filesystem operations.
| io_uring | [rustix::io_uring]—Linux io_uring.
| mm | [rustix::mm]—Memory map operations.
| net | [rustix::net] and [rustix::path]—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.
| 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 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.
rustix is similar to [nix], [simple_libc], [unix], [nc], and
[uapi]. 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, though rustix can use either the
Rust asm! macro or out-of-line .s files so it supports Rust versions from
1.63 through Nightly and architectures where Rust's inline asm is not yet
stable. 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 enums rather than bare integers. And, rustix calls its
tcgetattr function tcgetattr, rather than Termios::from_fd.
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.