make `std::os::unix::ucred` module private

1 files changed, 135 insertions, 0 deletions

diff --git a/library/std/src/os/unix/net/ucred.rs b/library/std/src/os/unix/net/ucred.rs
new file mode 100644
index 00000000000..de09c93840a
--- /dev/null
+++ b/library/std/src/os/unix/net/ucred.rs
@@ -0,0 +1,135 @@
+// NOTE: Code in this file is heavily based on work done in PR 13 from the tokio-uds repository on
+//       GitHub.
+//
+//       For reference, the link is here: https://github.com/tokio-rs/tokio-uds/pull/13
+//       Credit to Martin Habovštiak (GitHub username Kixunil) and contributors for this work.
+
+use libc::{gid_t, pid_t, uid_t};
+
+/// Credentials for a UNIX process for credentials passing.
+#[unstable(feature = "peer_credentials_unix_socket", issue = "42839", reason = "unstable")]
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+pub struct UCred {
+    /// The UID part of the peer credential. This is the effective UID of the process at the domain
+    /// socket's endpoint.
+    pub uid: uid_t,
+    /// The GID part of the peer credential. This is the effective GID of the process at the domain
+    /// socket's endpoint.
+    pub gid: gid_t,
+    /// The PID part of the peer credential. This field is optional because the PID part of the
+    /// peer credentials is not supported on every platform. On platforms where the mechanism to
+    /// discover the PID exists, this field will be populated to the PID of the process at the
+    /// domain socket's endpoint. Otherwise, it will be set to None.
+    pub pid: Option<pid_t>,
+}
+
+#[cfg(any(target_os = "android", target_os = "linux"))]
+pub(super) use self::impl_linux::peer_cred;
+
+#[cfg(any(
+    target_os = "dragonfly",
+    target_os = "freebsd",
+    target_os = "openbsd",
+    target_os = "netbsd"
+))]
+pub(super) use self::impl_bsd::peer_cred;
+
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "tvos", target_os = "watchos"))]
+pub(super) use self::impl_mac::peer_cred;
+
+#[cfg(any(target_os = "linux", target_os = "android"))]
+mod impl_linux {
+    use super::UCred;
+    use crate::os::unix::io::AsRawFd;
+    use crate::os::unix::net::UnixStream;
+    use crate::{io, mem};
+    use libc::{c_void, getsockopt, socklen_t, ucred, SOL_SOCKET, SO_PEERCRED};
+
+    pub fn peer_cred(socket: &UnixStream) -> io::Result<UCred> {
+        let ucred_size = mem::size_of::<ucred>();
+
+        // Trivial sanity checks.
+        assert!(mem::size_of::<u32>() <= mem::size_of::<usize>());
+        assert!(ucred_size <= u32::MAX as usize);
+
+        let mut ucred_size = ucred_size as socklen_t;
+        let mut ucred: ucred = ucred { pid: 1, uid: 1, gid: 1 };
+
+        unsafe {
+            let ret = getsockopt(
+                socket.as_raw_fd(),
+                SOL_SOCKET,
+                SO_PEERCRED,
+                core::ptr::addr_of_mut!(ucred) as *mut c_void,
+                &mut ucred_size,
+            );
+
+            if ret == 0 && ucred_size as usize == mem::size_of::<ucred>() {
+                Ok(UCred { uid: ucred.uid, gid: ucred.gid, pid: Some(ucred.pid) })
+            } else {
+                Err(io::Error::last_os_error())
+            }
+        }
+    }
+}
+
+#[cfg(any(
+    target_os = "dragonfly",
+    target_os = "freebsd",
+    target_os = "openbsd",
+    target_os = "netbsd",
+    target_os = "nto",
+))]
+mod impl_bsd {
+    use super::UCred;
+    use crate::io;
+    use crate::os::unix::io::AsRawFd;
+    use crate::os::unix::net::UnixStream;
+
+    pub fn peer_cred(socket: &UnixStream) -> io::Result<UCred> {
+        let mut cred = UCred { uid: 1, gid: 1, pid: None };
+        unsafe {
+            let ret = libc::getpeereid(socket.as_raw_fd(), &mut cred.uid, &mut cred.gid);
+
+            if ret == 0 { Ok(cred) } else { Err(io::Error::last_os_error()) }
+        }
+    }
+}
+
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "tvos", target_os = "watchos"))]
+mod impl_mac {
+    use super::UCred;
+    use crate::os::unix::io::AsRawFd;
+    use crate::os::unix::net::UnixStream;
+    use crate::{io, mem};
+    use libc::{c_void, getpeereid, getsockopt, pid_t, socklen_t, LOCAL_PEERPID, SOL_LOCAL};
+
+    pub fn peer_cred(socket: &UnixStream) -> io::Result<UCred> {
+        let mut cred = UCred { uid: 1, gid: 1, pid: None };
+        unsafe {
+            let ret = getpeereid(socket.as_raw_fd(), &mut cred.uid, &mut cred.gid);
+
+            if ret != 0 {
+                return Err(io::Error::last_os_error());
+            }
+
+            let mut pid: pid_t = 1;
+            let mut pid_size = mem::size_of::<pid_t>() as socklen_t;
+
+            let ret = getsockopt(
+                socket.as_raw_fd(),
+                SOL_LOCAL,
+                LOCAL_PEERPID,
+                core::ptr::addr_of_mut!(pid) as *mut c_void,
+                &mut pid_size,
+            );
+
+            if ret == 0 && pid_size as usize == mem::size_of::<pid_t>() {
+                cred.pid = Some(pid);
+                Ok(cred)
+            } else {
+                Err(io::Error::last_os_error())
+            }
+        }
+    }
+}