Add cr_pid to FreeBSD xucred - an unreleased addition in FreeBSD 13

definition: https://svnweb.freebsd.org/base/head/sys/sys/ucred.h?view=markup#l85
manpage: https://www.freebsd.org/cgi/man.cgi?query=unix&sektion=0&manpath=FreeBSD+13-current&format=html

Continue comparing and hashing __cr_unused1 for backwards compatibility.

libc-test/build.rs

@@ -1821,6 +1821,9 @@ fn test_freebsd(target: &str) {
     });
 
     cfg.skip_struct(move |ty| {
+        if ty.starts_with("__c_anonymous_") {
+            return true;
+        }
         match ty {
             // `mmsghdr` is not available in FreeBSD 10
             "mmsghdr" if Some(10) == freebsd_ver => true,
@@ -1898,6 +1901,9 @@ fn test_freebsd(target: &str) {
             ("Elf32_Phdr", "p_type") => true,
             ("Elf64_Phdr", "p_type") => true,
 
+            // not available until FreeBSD 12, and is an anonymous union there.
+            ("xucred", "cr_pid__c_anonymous_union") => true,
+
             _ => false,
         }
     });

src/unix/bsd/freebsdlike/dragonfly/mod.rs

@@ -171,6 +171,14 @@ s! {
         pub sdl_route: [::c_ushort; 16],
     }
 
+    pub struct xucred {
+        pub cr_version: ::c_uint,
+        pub cr_uid: ::uid_t,
+        pub cr_ngroups: ::c_short,
+        pub cr_groups: [::gid_t; 16],
+        __cr_unused1: *mut ::c_void,
+    }
+
     pub struct stack_t {
         pub ss_sp: *mut ::c_char,
         pub ss_size: ::size_t,
@@ -238,7 +246,6 @@ s_no_extra_traits! {
         pub sigev_value: ::sigval,
         __unused3: *mut ::c_void        //actually a function pointer
     }
-
 }
 
 cfg_if! {

src/unix/bsd/freebsdlike/freebsd/mod.rs

@@ -135,6 +135,23 @@ s_no_extra_traits! {
         pub __ut_spare: [::c_char; 64],
     }
 
+    #[cfg(libc_union)]
+    pub union __c_anonymous_cr_pid {
+        __cr_unused: *mut ::c_void,
+        pub cr_pid: ::pid_t,
+    }
+
+    pub struct xucred {
+        pub cr_version: ::c_uint,
+        pub cr_uid: ::uid_t,
+        pub cr_ngroups: ::c_short,
+        pub cr_groups: [::gid_t; 16],
+        #[cfg(libc_union)]
+        pub cr_pid__c_anonymous_union: __c_anonymous_cr_pid,
+        #[cfg(not(libc_union))]
+        __cr_unused1: *mut ::c_void,
+    }
+
     pub struct sockaddr_dl {
         pub sdl_len: ::c_uchar,
         pub sdl_family: ::c_uchar,
@@ -217,6 +234,73 @@ cfg_if! {
             }
         }
 
+        #[cfg(libc_union)]
+        impl PartialEq for __c_anonymous_cr_pid {
+            fn eq(&self, other: &__c_anonymous_cr_pid) -> bool {
+                unsafe { self.cr_pid == other.cr_pid}
+            }
+        }
+        #[cfg(libc_union)]
+        impl Eq for __c_anonymous_cr_pid {}
+        #[cfg(libc_union)]
+        impl ::fmt::Debug for __c_anonymous_cr_pid {
+            fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
+                f.debug_struct("cr_pid")
+                    .field("cr_pid", unsafe { &self.cr_pid })
+                    .finish()
+            }
+        }
+        #[cfg(libc_union)]
+        impl ::hash::Hash for __c_anonymous_cr_pid {
+            fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
+                unsafe { self.cr_pid.hash(state) };
+            }
+        }
+
+        impl PartialEq for xucred {
+            fn eq(&self, other: &xucred) -> bool {
+                #[cfg(libc_union)]
+                let equal_cr_pid = self.cr_pid__c_anonymous_union
+                    == other.cr_pid__c_anonymous_union;
+                #[cfg(not(libc_union))]
+                let equal_cr_pid = self.__cr_unused1 == other.__cr_unused1;
+
+                self.cr_version == other.cr_version
+                    && self.cr_uid == other.cr_uid
+                    && self.cr_ngroups == other.cr_ngroups
+                    && self.cr_groups == other.cr_groups
+                    && equal_cr_pid
+            }
+        }
+        impl Eq for xucred {}
+        impl ::fmt::Debug for xucred {
+            fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
+                let mut struct_formatter = f.debug_struct("xucred");
+                struct_formatter.field("cr_version", &self.cr_version);
+                struct_formatter.field("cr_uid", &self.cr_uid);
+                struct_formatter.field("cr_ngroups", &self.cr_ngroups);
+                struct_formatter.field("cr_groups", &self.cr_groups);
+                #[cfg(libc_union)]
+                struct_formatter.field(
+                    "cr_pid__c_anonymous_union",
+                    &self.cr_pid__c_anonymous_union
+                );
+                struct_formatter.finish()
+            }
+        }
+        impl ::hash::Hash for xucred {
+            fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
+                self.cr_version.hash(state);
+                self.cr_uid.hash(state);
+                self.cr_ngroups.hash(state);
+                self.cr_groups.hash(state);
+                #[cfg(libc_union)]
+                self.cr_pid__c_anonymous_union.hash(state);
+                #[cfg(not(libc_union))]
+                self.__cr_unused1.hash(state);
+            }
+        }
+
         impl PartialEq for sockaddr_dl {
             fn eq(&self, other: &sockaddr_dl) -> bool {
                 self.sdl_len == other.sdl_len

src/unix/bsd/freebsdlike/mod.rs

@@ -219,14 +219,6 @@ s! {
         pub cmcred_groups: [::gid_t; CMGROUP_MAX],
     }
 
-    pub struct xucred {
-        pub cr_version: ::c_uint,
-        pub cr_uid: ::uid_t,
-        pub cr_ngroups: ::c_short,
-        pub cr_groups: [::gid_t; 16],
-        __cr_unused1: *mut ::c_void,
-    }
-
     pub struct rtprio {
         pub type_: ::c_ushort,
         pub prio: ::c_ushort,