rustix/backend/linux_raw/net/
addr.rs

1//! Socket address utilities.
2//!
3//! # Safety
4//!
5//! This file uses `CStr::from_bytes_with_nul_unchecked` on a string it knows
6//! to be NUL-terminated.
7#![allow(unsafe_code)]
8
9use crate::backend::c;
10use crate::ffi::CStr;
11use crate::{io, path};
12use core::cmp::Ordering;
13use core::hash::{Hash, Hasher};
14use core::{fmt, slice};
15
16/// `struct sockaddr_un`
17#[derive(Clone)]
18#[doc(alias = "sockaddr_un")]
19pub struct SocketAddrUnix {
20    pub(crate) unix: c::sockaddr_un,
21    len: c::socklen_t,
22}
23
24impl SocketAddrUnix {
25    /// Construct a new Unix-domain address from a filesystem path.
26    #[inline]
27    pub fn new<P: path::Arg>(path: P) -> io::Result<Self> {
28        path.into_with_c_str(Self::_new)
29    }
30
31    #[inline]
32    fn _new(path: &CStr) -> io::Result<Self> {
33        let mut unix = Self::init();
34        let bytes = path.to_bytes_with_nul();
35        if bytes.len() > unix.sun_path.len() {
36            return Err(io::Errno::NAMETOOLONG);
37        }
38        for (i, b) in bytes.iter().enumerate() {
39            unix.sun_path[i] = *b as _;
40        }
41        let len = offsetof_sun_path() + bytes.len();
42        let len = len.try_into().unwrap();
43        Ok(Self { unix, len })
44    }
45
46    /// Construct a new abstract Unix-domain address from a byte slice.
47    #[inline]
48    pub fn new_abstract_name(name: &[u8]) -> io::Result<Self> {
49        let mut unix = Self::init();
50        let id = &mut unix.sun_path[1..];
51
52        // SAFETY: Convert `&mut [c_char]` to `&mut [u8]`.
53        let id = unsafe { slice::from_raw_parts_mut(id.as_mut_ptr().cast::<u8>(), id.len()) };
54
55        if let Some(id) = id.get_mut(..name.len()) {
56            id.copy_from_slice(name);
57            let len = offsetof_sun_path() + 1 + name.len();
58            let len = len.try_into().unwrap();
59            Ok(Self { unix, len })
60        } else {
61            Err(io::Errno::NAMETOOLONG)
62        }
63    }
64
65    const fn init() -> c::sockaddr_un {
66        c::sockaddr_un {
67            sun_family: c::AF_UNIX as _,
68            sun_path: [0; 108],
69        }
70    }
71
72    /// For a filesystem path address, return the path.
73    #[inline]
74    pub fn path(&self) -> Option<&CStr> {
75        let len = self.len();
76        if len != 0 && self.unix.sun_path[0] as u8 != b'\0' {
77            let end = len as usize - offsetof_sun_path();
78            let bytes = &self.unix.sun_path[..end];
79
80            // SAFETY: Convert `&[c_char]` to `&[u8]`.
81            let bytes = unsafe { slice::from_raw_parts(bytes.as_ptr().cast::<u8>(), bytes.len()) };
82
83            // SAFETY: `from_bytes_with_nul_unchecked` since the string is
84            // NUL-terminated.
85            unsafe { Some(CStr::from_bytes_with_nul_unchecked(bytes)) }
86        } else {
87            None
88        }
89    }
90
91    /// For an abstract address, return the identifier.
92    #[inline]
93    pub fn abstract_name(&self) -> Option<&[u8]> {
94        let len = self.len();
95        if len != 0 && self.unix.sun_path[0] as u8 == b'\0' {
96            let end = len as usize - offsetof_sun_path();
97            let bytes = &self.unix.sun_path[1..end];
98
99            // SAFETY: Convert `&[c_char]` to `&[u8]`.
100            let bytes = unsafe { slice::from_raw_parts(bytes.as_ptr().cast::<u8>(), bytes.len()) };
101
102            Some(bytes)
103        } else {
104            None
105        }
106    }
107
108    #[inline]
109    pub(crate) fn addr_len(&self) -> c::socklen_t {
110        self.len
111    }
112
113    #[inline]
114    pub(crate) fn len(&self) -> usize {
115        self.addr_len() as usize
116    }
117}
118
119impl PartialEq for SocketAddrUnix {
120    #[inline]
121    fn eq(&self, other: &Self) -> bool {
122        let self_len = self.len() - offsetof_sun_path();
123        let other_len = other.len() - offsetof_sun_path();
124        self.unix.sun_path[..self_len].eq(&other.unix.sun_path[..other_len])
125    }
126}
127
128impl Eq for SocketAddrUnix {}
129
130impl PartialOrd for SocketAddrUnix {
131    #[inline]
132    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
133        Some(self.cmp(other))
134    }
135}
136
137impl Ord for SocketAddrUnix {
138    #[inline]
139    fn cmp(&self, other: &Self) -> Ordering {
140        let self_len = self.len() - offsetof_sun_path();
141        let other_len = other.len() - offsetof_sun_path();
142        self.unix.sun_path[..self_len].cmp(&other.unix.sun_path[..other_len])
143    }
144}
145
146impl Hash for SocketAddrUnix {
147    #[inline]
148    fn hash<H: Hasher>(&self, state: &mut H) {
149        let self_len = self.len() - offsetof_sun_path();
150        self.unix.sun_path[..self_len].hash(state)
151    }
152}
153
154impl fmt::Debug for SocketAddrUnix {
155    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
156        if let Some(path) = self.path() {
157            path.fmt(f)
158        } else if let Some(name) = self.abstract_name() {
159            name.fmt(f)
160        } else {
161            "(unnamed)".fmt(f)
162        }
163    }
164}
165
166/// `struct sockaddr_storage` as a raw struct.
167pub type SocketAddrStorage = c::sockaddr;
168
169/// Return the offset of the `sun_path` field of `sockaddr_un`.
170#[inline]
171pub(crate) fn offsetof_sun_path() -> usize {
172    let z = c::sockaddr_un {
173        sun_family: 0_u16,
174        sun_path: [0; 108],
175    };
176    (crate::utils::as_ptr(&z.sun_path) as usize) - (crate::utils::as_ptr(&z) as usize)
177}
rustix/backend/linux_raw/net/addr.rs

rustix/backend/linux_raw/net/
addr.rs
