diff options
Diffstat (limited to '')
| -rw-r--r-- | library/std/src/os/unix/net/addr.rs | 350 |
1 files changed, 350 insertions, 0 deletions
diff --git a/library/std/src/os/unix/net/addr.rs b/library/std/src/os/unix/net/addr.rs new file mode 100644 index 000000000..9aeae4b2c --- /dev/null +++ b/library/std/src/os/unix/net/addr.rs @@ -0,0 +1,350 @@ +use crate::ffi::OsStr; +use crate::os::unix::ffi::OsStrExt; +use crate::path::Path; +use crate::sys::cvt; +use crate::{ascii, fmt, io, mem, ptr}; + +// FIXME(#43348): Make libc adapt #[doc(cfg(...))] so we don't need these fake definitions here? +#[cfg(not(unix))] +#[allow(non_camel_case_types)] +mod libc { + pub use libc::c_int; + pub type socklen_t = u32; + pub struct sockaddr; + #[derive(Clone)] + pub struct sockaddr_un; +} + +fn sun_path_offset(addr: &libc::sockaddr_un) -> usize { + // Work with an actual instance of the type since using a null pointer is UB + let base = (addr as *const libc::sockaddr_un).addr(); + let path = (&addr.sun_path as *const libc::c_char).addr(); + path - base +} + +pub(super) fn sockaddr_un(path: &Path) -> io::Result<(libc::sockaddr_un, libc::socklen_t)> { + // SAFETY: All zeros is a valid representation for `sockaddr_un`. + let mut addr: libc::sockaddr_un = unsafe { mem::zeroed() }; + addr.sun_family = libc::AF_UNIX as libc::sa_family_t; + + let bytes = path.as_os_str().as_bytes(); + + if bytes.contains(&0) { + return Err(io::const_io_error!( + io::ErrorKind::InvalidInput, + "paths must not contain interior null bytes", + )); + } + + if bytes.len() >= addr.sun_path.len() { + return Err(io::const_io_error!( + io::ErrorKind::InvalidInput, + "path must be shorter than SUN_LEN", + )); + } + // SAFETY: `bytes` and `addr.sun_path` are not overlapping and + // both point to valid memory. + // NOTE: We zeroed the memory above, so the path is already null + // terminated. + unsafe { + ptr::copy_nonoverlapping(bytes.as_ptr(), addr.sun_path.as_mut_ptr().cast(), bytes.len()) + }; + + let mut len = sun_path_offset(&addr) + bytes.len(); + match bytes.get(0) { + Some(&0) | None => {} + Some(_) => len += 1, + } + Ok((addr, len as libc::socklen_t)) +} + +enum AddressKind<'a> { + Unnamed, + Pathname(&'a Path), + Abstract(&'a [u8]), +} + +struct AsciiEscaped<'a>(&'a [u8]); + +impl<'a> fmt::Display for AsciiEscaped<'a> { + fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(fmt, "\"")?; + for byte in self.0.iter().cloned().flat_map(ascii::escape_default) { + write!(fmt, "{}", byte as char)?; + } + write!(fmt, "\"") + } +} + +/// An address associated with a Unix socket. +/// +/// # Examples +/// +/// ``` +/// use std::os::unix::net::UnixListener; +/// +/// let socket = match UnixListener::bind("/tmp/sock") { +/// Ok(sock) => sock, +/// Err(e) => { +/// println!("Couldn't bind: {e:?}"); +/// return +/// } +/// }; +/// let addr = socket.local_addr().expect("Couldn't get local address"); +/// ``` +#[derive(Clone)] +#[stable(feature = "unix_socket", since = "1.10.0")] +pub struct SocketAddr { + pub(super) addr: libc::sockaddr_un, + pub(super) len: libc::socklen_t, +} + +impl SocketAddr { + pub(super) fn new<F>(f: F) -> io::Result<SocketAddr> + where + F: FnOnce(*mut libc::sockaddr, *mut libc::socklen_t) -> libc::c_int, + { + unsafe { + let mut addr: libc::sockaddr_un = mem::zeroed(); + let mut len = mem::size_of::<libc::sockaddr_un>() as libc::socklen_t; + cvt(f(&mut addr as *mut _ as *mut _, &mut len))?; + SocketAddr::from_parts(addr, len) + } + } + + pub(super) fn from_parts( + addr: libc::sockaddr_un, + mut len: libc::socklen_t, + ) -> io::Result<SocketAddr> { + if len == 0 { + // When there is a datagram from unnamed unix socket + // linux returns zero bytes of address + len = sun_path_offset(&addr) as libc::socklen_t; // i.e., zero-length address + } else if addr.sun_family != libc::AF_UNIX as libc::sa_family_t { + return Err(io::const_io_error!( + io::ErrorKind::InvalidInput, + "file descriptor did not correspond to a Unix socket", + )); + } + + Ok(SocketAddr { addr, len }) + } + + /// Constructs a `SockAddr` with the family `AF_UNIX` and the provided path. + /// + /// # Errors + /// + /// Returns an error if the path is longer than `SUN_LEN` or if it contains + /// NULL bytes. + /// + /// # Examples + /// + /// ``` + /// use std::os::unix::net::SocketAddr; + /// use std::path::Path; + /// + /// # fn main() -> std::io::Result<()> { + /// let address = SocketAddr::from_pathname("/path/to/socket")?; + /// assert_eq!(address.as_pathname(), Some(Path::new("/path/to/socket"))); + /// # Ok(()) + /// # } + /// ``` + /// + /// Creating a `SocketAddr` with a NULL byte results in an error. + /// + /// ``` + /// use std::os::unix::net::SocketAddr; + /// + /// assert!(SocketAddr::from_pathname("/path/with/\0/bytes").is_err()); + /// ``` + #[stable(feature = "unix_socket_creation", since = "1.61.0")] + pub fn from_pathname<P>(path: P) -> io::Result<SocketAddr> + where + P: AsRef<Path>, + { + sockaddr_un(path.as_ref()).map(|(addr, len)| SocketAddr { addr, len }) + } + + /// Returns `true` if the address is unnamed. + /// + /// # Examples + /// + /// A named address: + /// + /// ```no_run + /// use std::os::unix::net::UnixListener; + /// + /// fn main() -> std::io::Result<()> { + /// let socket = UnixListener::bind("/tmp/sock")?; + /// let addr = socket.local_addr().expect("Couldn't get local address"); + /// assert_eq!(addr.is_unnamed(), false); + /// Ok(()) + /// } + /// ``` + /// + /// An unnamed address: + /// + /// ``` + /// use std::os::unix::net::UnixDatagram; + /// + /// fn main() -> std::io::Result<()> { + /// let socket = UnixDatagram::unbound()?; + /// let addr = socket.local_addr().expect("Couldn't get local address"); + /// assert_eq!(addr.is_unnamed(), true); + /// Ok(()) + /// } + /// ``` + #[must_use] + #[stable(feature = "unix_socket", since = "1.10.0")] + pub fn is_unnamed(&self) -> bool { + matches!(self.address(), AddressKind::Unnamed) + } + + /// Returns the contents of this address if it is a `pathname` address. + /// + /// # Examples + /// + /// With a pathname: + /// + /// ```no_run + /// use std::os::unix::net::UnixListener; + /// use std::path::Path; + /// + /// fn main() -> std::io::Result<()> { + /// let socket = UnixListener::bind("/tmp/sock")?; + /// let addr = socket.local_addr().expect("Couldn't get local address"); + /// assert_eq!(addr.as_pathname(), Some(Path::new("/tmp/sock"))); + /// Ok(()) + /// } + /// ``` + /// + /// Without a pathname: + /// + /// ``` + /// use std::os::unix::net::UnixDatagram; + /// + /// fn main() -> std::io::Result<()> { + /// let socket = UnixDatagram::unbound()?; + /// let addr = socket.local_addr().expect("Couldn't get local address"); + /// assert_eq!(addr.as_pathname(), None); + /// Ok(()) + /// } + /// ``` + #[stable(feature = "unix_socket", since = "1.10.0")] + #[must_use] + pub fn as_pathname(&self) -> Option<&Path> { + if let AddressKind::Pathname(path) = self.address() { Some(path) } else { None } + } + + /// Returns the contents of this address if it is an abstract namespace + /// without the leading null byte. + /// + /// # Examples + /// + /// ```no_run + /// #![feature(unix_socket_abstract)] + /// use std::os::unix::net::{UnixListener, SocketAddr}; + /// + /// fn main() -> std::io::Result<()> { + /// let namespace = b"hidden"; + /// let namespace_addr = SocketAddr::from_abstract_namespace(&namespace[..])?; + /// let socket = UnixListener::bind_addr(&namespace_addr)?; + /// let local_addr = socket.local_addr().expect("Couldn't get local address"); + /// assert_eq!(local_addr.as_abstract_namespace(), Some(&namespace[..])); + /// Ok(()) + /// } + /// ``` + #[doc(cfg(any(target_os = "android", target_os = "linux")))] + #[cfg(any(doc, target_os = "android", target_os = "linux",))] + #[unstable(feature = "unix_socket_abstract", issue = "85410")] + pub fn as_abstract_namespace(&self) -> Option<&[u8]> { + if let AddressKind::Abstract(name) = self.address() { Some(name) } else { None } + } + + fn address(&self) -> AddressKind<'_> { + let len = self.len as usize - sun_path_offset(&self.addr); + let path = unsafe { mem::transmute::<&[libc::c_char], &[u8]>(&self.addr.sun_path) }; + + // macOS seems to return a len of 16 and a zeroed sun_path for unnamed addresses + if len == 0 + || (cfg!(not(any(target_os = "linux", target_os = "android"))) + && self.addr.sun_path[0] == 0) + { + AddressKind::Unnamed + } else if self.addr.sun_path[0] == 0 { + AddressKind::Abstract(&path[1..len]) + } else { + AddressKind::Pathname(OsStr::from_bytes(&path[..len - 1]).as_ref()) + } + } + + /// Creates an abstract domain socket address from a namespace + /// + /// An abstract address does not create a file unlike traditional path-based + /// Unix sockets. The advantage of this is that the address will disappear when + /// the socket bound to it is closed, so no filesystem clean up is required. + /// + /// The leading null byte for the abstract namespace is automatically added. + /// + /// This is a Linux-specific extension. See more at [`unix(7)`]. + /// + /// [`unix(7)`]: https://man7.org/linux/man-pages/man7/unix.7.html + /// + /// # Errors + /// + /// This will return an error if the given namespace is too long + /// + /// # Examples + /// + /// ```no_run + /// #![feature(unix_socket_abstract)] + /// use std::os::unix::net::{UnixListener, SocketAddr}; + /// + /// fn main() -> std::io::Result<()> { + /// let addr = SocketAddr::from_abstract_namespace(b"hidden")?; + /// let listener = match UnixListener::bind_addr(&addr) { + /// Ok(sock) => sock, + /// Err(err) => { + /// println!("Couldn't bind: {err:?}"); + /// return Err(err); + /// } + /// }; + /// Ok(()) + /// } + /// ``` + #[doc(cfg(any(target_os = "android", target_os = "linux")))] + #[cfg(any(doc, target_os = "android", target_os = "linux",))] + #[unstable(feature = "unix_socket_abstract", issue = "85410")] + pub fn from_abstract_namespace(namespace: &[u8]) -> io::Result<SocketAddr> { + unsafe { + let mut addr: libc::sockaddr_un = mem::zeroed(); + addr.sun_family = libc::AF_UNIX as libc::sa_family_t; + + if namespace.len() + 1 > addr.sun_path.len() { + return Err(io::const_io_error!( + io::ErrorKind::InvalidInput, + "namespace must be shorter than SUN_LEN", + )); + } + + crate::ptr::copy_nonoverlapping( + namespace.as_ptr(), + addr.sun_path.as_mut_ptr().offset(1) as *mut u8, + namespace.len(), + ); + let len = (sun_path_offset(&addr) + 1 + namespace.len()) as libc::socklen_t; + SocketAddr::from_parts(addr, len) + } + } +} + +#[stable(feature = "unix_socket", since = "1.10.0")] +impl fmt::Debug for SocketAddr { + fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { + match self.address() { + AddressKind::Unnamed => write!(fmt, "(unnamed)"), + AddressKind::Abstract(name) => write!(fmt, "{} (abstract)", AsciiEscaped(name)), + AddressKind::Pathname(path) => write!(fmt, "{path:?} (pathname)"), + } + } +} |