library/std/src/os/unix/ucred.rs

   1 //! Unix peer credentials.
   2
   3 // NOTE: Code in this file is heavily based on work done in PR 13 from the tokio-uds repository on
   4 //       GitHub.
   5 //
   6 //       For reference, the link is here: https://github.com/tokio-rs/tokio-uds/pull/13
   7 //       Credit to Martin Habovštiak (GitHub username Kixunil) and contributors for this work.
   8
   9 use libc::{gid_t, pid_t, uid_t};
  10
  11 /// Credentials for a UNIX process for credentials passing.
  12 #[unstable(feature = "peer_credentials_unix_socket", issue = "42839", reason = "unstable")]
  13 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
  14 pub struct UCred {
  15     /// The UID part of the peer credential. This is the effective UID of the process at the domain
  16     /// socket's endpoint.
  17     pub uid: uid_t,
  18     /// The GID part of the peer credential. This is the effective GID of the process at the domain
  19     /// socket's endpoint.
  20     pub gid: gid_t,
  21     /// The PID part of the peer credential. This field is optional because the PID part of the
  22     /// peer credentials is not supported on every platform. On platforms where the mechanism to
  23     /// discover the PID exists, this field will be populated to the PID of the process at the
  24     /// domain socket's endpoint. Otherwise, it will be set to None.
  25     pub pid: Option<pid_t>,
  26 }
  27
  28 #[cfg(any(target_os = "android", target_os = "linux"))]
  29 pub use self::impl_linux::peer_cred;
  30
  31 #[cfg(any(
  32     target_os = "dragonfly",
  33     target_os = "freebsd",
  34     target_os = "openbsd",
  35     target_os = "netbsd"
  36 ))]
  37 pub use self::impl_bsd::peer_cred;
  38
  39 #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
  40 pub use self::impl_mac::peer_cred;
  41
  42 #[cfg(any(target_os = "linux", target_os = "android"))]
  43 pub mod impl_linux {
  44     use super::UCred;
  45     use crate::os::unix::io::AsRawFd;
  46     use crate::os::unix::net::UnixStream;
  47     use crate::{io, mem};
  48     use libc::{c_void, getsockopt, socklen_t, ucred, SOL_SOCKET, SO_PEERCRED};
  49
  50     pub fn peer_cred(socket: &UnixStream) -> io::Result<UCred> {
  51         let ucred_size = mem::size_of::<ucred>();
  52
  53         // Trivial sanity checks.
  54         assert!(mem::size_of::<u32>() <= mem::size_of::<usize>());
  55         assert!(ucred_size <= u32::MAX as usize);
  56
  57         let mut ucred_size = ucred_size as socklen_t;
  58         let mut ucred: ucred = ucred { pid: 1, uid: 1, gid: 1 };
  59
  60         unsafe {
  61             let ret = getsockopt(
  62                 socket.as_raw_fd(),
  63                 SOL_SOCKET,
  64                 SO_PEERCRED,
  65                 &mut ucred as *mut ucred as *mut c_void,
  66                 &mut ucred_size,
  67             );
  68
  69             if ret == 0 && ucred_size as usize == mem::size_of::<ucred>() {
  70                 Ok(UCred { uid: ucred.uid, gid: ucred.gid, pid: Some(ucred.pid) })
  71             } else {
  72                 Err(io::Error::last_os_error())
  73             }
  74         }
  75     }
  76 }
  77
  78 #[cfg(any(
  79     target_os = "dragonfly",
  80     target_os = "freebsd",
  81     target_os = "openbsd",
  82     target_os = "netbsd",
  83     target_os = "nto",
  84 ))]
  85 pub mod impl_bsd {
  86     use super::UCred;
  87     use crate::io;
  88     use crate::os::unix::io::AsRawFd;
  89     use crate::os::unix::net::UnixStream;
  90
  91     pub fn peer_cred(socket: &UnixStream) -> io::Result<UCred> {
  92         let mut cred = UCred { uid: 1, gid: 1, pid: None };
  93         unsafe {
  94             let ret = libc::getpeereid(socket.as_raw_fd(), &mut cred.uid, &mut cred.gid);
  95
  96             if ret == 0 { Ok(cred) } else { Err(io::Error::last_os_error()) }
  97         }
  98     }
  99 }
 100
 101 #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
 102 pub mod impl_mac {
 103     use super::UCred;
 104     use crate::os::unix::io::AsRawFd;
 105     use crate::os::unix::net::UnixStream;
 106     use crate::{io, mem};
 107     use libc::{c_void, getpeereid, getsockopt, pid_t, socklen_t, LOCAL_PEERPID, SOL_LOCAL};
 108
 109     pub fn peer_cred(socket: &UnixStream) -> io::Result<UCred> {
 110         let mut cred = UCred { uid: 1, gid: 1, pid: None };
 111         unsafe {
 112             let ret = getpeereid(socket.as_raw_fd(), &mut cred.uid, &mut cred.gid);
 113
 114             if ret != 0 {
 115                 return Err(io::Error::last_os_error());
 116             }
 117
 118             let mut pid: pid_t = 1;
 119             let mut pid_size = mem::size_of::<pid_t>() as socklen_t;
 120
 121             let ret = getsockopt(
 122                 socket.as_raw_fd(),
 123                 SOL_LOCAL,
 124                 LOCAL_PEERPID,
 125                 &mut pid as *mut pid_t as *mut c_void,
 126                 &mut pid_size,
 127             );
 128
 129             if ret == 0 && pid_size as usize == mem::size_of::<pid_t>() {
 130                 cred.pid = Some(pid);
 131                 Ok(cred)
 132             } else {
 133                 Err(io::Error::last_os_error())
 134             }
 135         }
 136     }
 137 }