Crate rustix

rustix provides efficient memory-safe and I/O-safe wrappers to POSIX-like, Unix-like, Linux, and Winsock2 syscall-like APIs, with configurable backends.

With rustix, you can write code like this:

let nread: usize = rustix::net::recv(&sock, buf, RecvFlags::PEEK)?;

instead of like this:

let nread: usize = unsafe {
    #[cfg(any(unix, target_os = "wasi"))]
    let raw = sock.as_raw_fd();
    #[cfg(windows)]
    let raw = sock.as_raw_socket();
    match libc::recv(
        raw as _,
        buf.as_mut_ptr().cast(),
        buf.len().try_into().unwrap_or(i32::MAX as _),
        MSG_PEEK,
    ) {
        -1 => return Err(std::io::Error::last_os_error()),
        nread => nread as usize,
    }
};

rustix’s APIs perform the following tasks:

• Error values are translated to Results.
• Buffers are passed as Rust slices.
• Out-parameters are presented as return values.
• Path arguments use Arg, so they accept any string type.
• File descriptors are passed and returned via AsFd and OwnedFd instead of bare integers, ensuring I/O safety.
• Constants use enums and bitflags types, and enable support for externally defined flags.
• Multiplexed functions (eg. fcntl, ioctl, etc.) are de-multiplexed.
• Variadic functions (eg. openat, etc.) are presented as non-variadic.
• Functions that return strings automatically allocate sufficient memory and retry the syscall as needed to determine the needed length.
• Functions and types which need l prefixes or 64 suffixes to enable large-file support (LFS) are used automatically. File sizes and offsets are always presented as u64 and i64.
• Behaviors that depend on the sizes of C types like long are hidden.
• In some places, more human-friendly and less historical-accident names are used (and documentation aliases are used so that the original names can still be searched for).
• Provide y2038 compatibility, on platforms which support this.
• Correct selected platform bugs, such as behavioral differences when running under seccomp.

Things they don’t do include:

• Detecting whether functions are supported at runtime, except in specific cases where new interfaces need to be detected to support y2038 and LFS.
• Hiding significant differences between platforms.
• Restricting ambient authorities.
• Imposing sandboxing features such as filesystem path or network address sandboxing.

See cap-std, system-interface, and io-streams for libraries which do hide significant differences between platforms, and cap-std which does perform sandboxing and restricts ambient authorities.

Modules

• eventevent
  Event operations.
• fd
  Export the *Fd types and traits that are used in rustix’s public API.
• ffi
  Utilities related to FFI bindings.
• fsfs
  Filesystem operations.
• io
  I/O operations.
• io_uringio_uring
  Linux io_uring.
• ioctl
  Unsafe ioctl API.
• mmmm
  Memory map operations.
• mountmount
  Linux mount API.
• netnet
  Network-related operations.
• paramparam
  Process parameters.
• pathfs or mount or net
  Filesystem path operations.
• pipepipe
  pipe and related APIs.
• processprocess
  Process-associated operations.
• procfsprocfs
  Utilities for working with /proc, where Linux’s procfs is typically mounted.
• ptypty
  Pseudoterminal operations.
• randrand
  Random-related operations.
• stdiostdio
  Functions returning the stdio file descriptors.
• systemsystem
  Uname and other system-level functions.
• termiostermios
  Terminal I/O stream operations.
• threadthread
  Thread-associated operations.
• timetime
  Time-related operations.

Macros

• cmsg_spacenet
  Macro for defining the amount of space used by CMSGs.
• cstr
  A macro for CStr literals.