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//! Socket address utilities.
//!
//! # Safety
//!
//! This file uses `CStr::from_bytes_with_nul_unchecked` on a string it knows
//! to be NUL-terminated.
#![allow(unsafe_code)]
use crate::backend::c;
use crate::ffi::CStr;
use crate::{io, path};
use core::cmp::Ordering;
use core::hash::{Hash, Hasher};
use core::{fmt, slice};
/// `struct sockaddr_un`
#[derive(Clone)]
#[doc(alias = "sockaddr_un")]
pub struct SocketAddrUnix {
pub(crate) unix: c::sockaddr_un,
len: c::socklen_t,
}
impl SocketAddrUnix {
/// Construct a new Unix-domain address from a filesystem path.
#[inline]
pub fn new<P: path::Arg>(path: P) -> io::Result<Self> {
path.into_with_c_str(Self::_new)
}
#[inline]
fn _new(path: &CStr) -> io::Result<Self> {
let mut unix = Self::init();
let bytes = path.to_bytes_with_nul();
if bytes.len() > unix.sun_path.len() {
return Err(io::Errno::NAMETOOLONG);
}
for (i, b) in bytes.iter().enumerate() {
unix.sun_path[i] = *b as _;
}
let len = offsetof_sun_path() + bytes.len();
let len = len.try_into().unwrap();
Ok(Self { unix, len })
}
/// Construct a new abstract Unix-domain address from a byte slice.
#[inline]
pub fn new_abstract_name(name: &[u8]) -> io::Result<Self> {
let mut unix = Self::init();
let id = &mut unix.sun_path[1..];
// SAFETY: Convert `&mut [c_char]` to `&mut [u8]`.
let id = unsafe { slice::from_raw_parts_mut(id.as_mut_ptr().cast::<u8>(), id.len()) };
if let Some(id) = id.get_mut(..name.len()) {
id.copy_from_slice(name);
let len = offsetof_sun_path() + 1 + name.len();
let len = len.try_into().unwrap();
Ok(Self { unix, len })
} else {
Err(io::Errno::NAMETOOLONG)
}
}
const fn init() -> c::sockaddr_un {
c::sockaddr_un {
sun_family: c::AF_UNIX as _,
sun_path: [0; 108],
}
}
/// For a filesystem path address, return the path.
#[inline]
pub fn path(&self) -> Option<&CStr> {
let len = self.len();
if len != 0 && self.unix.sun_path[0] as u8 != b'\0' {
let end = len as usize - offsetof_sun_path();
let bytes = &self.unix.sun_path[..end];
// SAFETY: Convert `&[c_char]` to `&[u8]`.
let bytes = unsafe { slice::from_raw_parts(bytes.as_ptr().cast::<u8>(), bytes.len()) };
// SAFETY: `from_bytes_with_nul_unchecked` since the string is
// NUL-terminated.
unsafe { Some(CStr::from_bytes_with_nul_unchecked(bytes)) }
} else {
None
}
}
/// For an abstract address, return the identifier.
#[inline]
pub fn abstract_name(&self) -> Option<&[u8]> {
let len = self.len();
if len != 0 && self.unix.sun_path[0] as u8 == b'\0' {
let end = len as usize - offsetof_sun_path();
let bytes = &self.unix.sun_path[1..end];
// SAFETY: Convert `&[c_char]` to `&[u8]`.
let bytes = unsafe { slice::from_raw_parts(bytes.as_ptr().cast::<u8>(), bytes.len()) };
Some(bytes)
} else {
None
}
}
#[inline]
pub(crate) fn addr_len(&self) -> c::socklen_t {
self.len
}
#[inline]
pub(crate) fn len(&self) -> usize {
self.addr_len() as usize
}
}
impl PartialEq for SocketAddrUnix {
#[inline]
fn eq(&self, other: &Self) -> bool {
let self_len = self.len() - offsetof_sun_path();
let other_len = other.len() - offsetof_sun_path();
self.unix.sun_path[..self_len].eq(&other.unix.sun_path[..other_len])
}
}
impl Eq for SocketAddrUnix {}
impl PartialOrd for SocketAddrUnix {
#[inline]
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl Ord for SocketAddrUnix {
#[inline]
fn cmp(&self, other: &Self) -> Ordering {
let self_len = self.len() - offsetof_sun_path();
let other_len = other.len() - offsetof_sun_path();
self.unix.sun_path[..self_len].cmp(&other.unix.sun_path[..other_len])
}
}
impl Hash for SocketAddrUnix {
#[inline]
fn hash<H: Hasher>(&self, state: &mut H) {
let self_len = self.len() - offsetof_sun_path();
self.unix.sun_path[..self_len].hash(state)
}
}
impl fmt::Debug for SocketAddrUnix {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
if let Some(path) = self.path() {
path.fmt(fmt)
} else if let Some(name) = self.abstract_name() {
name.fmt(fmt)
} else {
"(unnamed)".fmt(fmt)
}
}
}
/// `struct sockaddr_storage` as a raw struct.
pub type SocketAddrStorage = c::sockaddr;
/// Return the offset of the `sun_path` field of `sockaddr_un`.
#[inline]
pub(crate) fn offsetof_sun_path() -> usize {
let z = c::sockaddr_un {
sun_family: 0_u16,
sun_path: [0; 108],
};
(crate::utils::as_ptr(&z.sun_path) as usize) - (crate::utils::as_ptr(&z) as usize)
}