Auto merge of #1212 - asomers:cmsg, r=alexcrichton

Fix CMSG_DATA(3) and friends on BSD

PR #1098 added the CMSG_DATA(3) family of functions into libc.  Because
they're defined as macros in C, they had to be rewritten as Rust
functions for libc.  Also, they can't be tested in CI for the same
reason.  But that PR erroneously used the same definitions in BSD as in
Linux.

This commit corrects the definitions for OSX, FreeBSD, DragonflyBSD,
OpenBSD, and NetBSD.  I renamed a few variables and collapsed a few
macros in order to combine the definitions where possible.

Fixes #1210

17 files changed, 220 insertions, 33 deletions

diff --git a/src/unix/bsd/apple/mod.rs b/src/unix/bsd/apple/mod.rs
index 13da82c383..837efff53d 100644
--- a/src/unix/bsd/apple/mod.rs
+++ b/src/unix/bsd/apple/mod.rs
@@ -1,6 +1,7 @@
 //! Apple (ios/darwin)-specific definitions
 //!
 //! This covers *-apple-* triples currently
+use dox::mem;
 
 pub type c_char = i8;
 pub type clock_t = c_ulong;
@@ -2383,7 +2384,45 @@ pub const SF_IMMUTABLE:     ::c_uint = 0x00020000;
 pub const SF_APPEND:        ::c_uint = 0x00040000;
 pub const UF_HIDDEN:        ::c_uint = 0x00008000;
 
+fn __DARWIN_ALIGN32(p: usize) -> usize {
+    const __DARWIN_ALIGNBYTES32: usize = mem::size_of::<u32>() - 1;
+    p + __DARWIN_ALIGNBYTES32 & !__DARWIN_ALIGNBYTES32
+}
+
 f! {
+    pub fn CMSG_NXTHDR(mhdr: *const ::msghdr,
+                       cmsg: *const ::cmsghdr) -> *mut ::cmsghdr {
+        if cmsg.is_null() {
+            return ::CMSG_FIRSTHDR(mhdr);
+        };
+        let cmsg_len = (*cmsg).cmsg_len as usize;
+        let next = cmsg as usize + __DARWIN_ALIGN32(cmsg_len as usize)
+            + __DARWIN_ALIGN32(mem::size_of::<::cmsghdr>());
+        let max = (*mhdr).msg_control as usize
+                   + (*mhdr).msg_controllen as usize;
+        if next > max {
+            0 as *mut ::cmsghdr
+        } else {
+            next as *mut ::cmsghdr
+        }
+    }
+
+    pub fn CMSG_DATA(cmsg: *const ::cmsghdr) -> *mut ::c_uchar {
+        (cmsg as *mut ::c_uchar)
+            .offset(__DARWIN_ALIGN32(mem::size_of::<::cmsghdr>()) as isize)
+    }
+
+    pub fn CMSG_SPACE(length: ::c_uint) -> ::c_uint {
+        (__DARWIN_ALIGN32(mem::size_of::<::cmsghdr>())
+            + __DARWIN_ALIGN32(length as usize))
+            as ::c_uint
+    }
+
+    pub fn CMSG_LEN(length: ::c_uint) -> ::c_uint {
+        __DARWIN_ALIGN32(mem::size_of::<::cmsghdr>() + length as usize)
+            as ::c_uint
+    }
+
     pub fn WSTOPSIG(status: ::c_int) -> ::c_int {
         status >> 8
     }
diff --git a/src/unix/bsd/freebsdlike/dragonfly/mod.rs b/src/unix/bsd/freebsdlike/dragonfly/mod.rs
index 41b695659a..b7029b01d7 100644
--- a/src/unix/bsd/freebsdlike/dragonfly/mod.rs
+++ b/src/unix/bsd/freebsdlike/dragonfly/mod.rs
@@ -782,6 +782,39 @@ pub const SF_NOHISTORY: ::c_ulong = 0x00400000;
 pub const SF_CACHE:     ::c_ulong = 0x00800000;
 pub const SF_XLINK:     ::c_ulong = 0x01000000;
 
+fn _CMSG_ALIGN(n: usize) -> usize {
+    (n + 3) & !3
+}
+
+f! {
+    pub fn CMSG_DATA(cmsg: *const ::cmsghdr) -> *mut ::c_uchar {
+        (cmsg as *mut ::c_uchar)
+            .offset(_CMSG_ALIGN(mem::size_of::<::cmsghdr>()) as isize)
+    }
+
+    pub fn CMSG_LEN(length: ::c_uint) -> ::c_uint {
+        _CMSG_ALIGN(mem::size_of::<::cmsghdr>()) + length as usize
+    }
+
+    pub fn CMSG_NXTHDR(mhdr: *const ::msghdr, cmsg: *const ::cmsghdr)
+        -> *mut ::cmsghdr
+    {
+        let next = cmsg as usize + _CMSG_ALIGN((*cmsg).cmsg_len)
+            + _CMSG_ALIGN(mem::size_of::<::cmsghdr>());
+        let max = (*mhdr).msg_control as usize
+            + (*mhdr).msg_controllen as usize;
+        if next <= max {
+            (cmsg as usize + _CMSG_ALIGN((*cmsg).cmsg_len)) as *mut ::cmsghdr
+        } else {
+            0 as *mut ::cmsghdr
+        }
+    }
+
+    pub fn CMSG_SPACE(length: ::c_uint) -> ::c_uint {
+        _CMSG_ALIGN(mem::size_of::<::cmsghdr>()) + _CMSG_ALIGN(length as usize)
+    }
+}
+
 extern {
     pub fn mprotect(addr: *mut ::c_void, len: ::size_t, prot: ::c_int)
                     -> ::c_int;
diff --git a/src/unix/bsd/freebsdlike/freebsd/aarch64.rs b/src/unix/bsd/freebsdlike/freebsd/aarch64.rs
index 3d61f889d8..d33b475234 100644
--- a/src/unix/bsd/freebsdlike/freebsd/aarch64.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/aarch64.rs
@@ -1,3 +1,5 @@
+use dox::mem;
+
 pub type c_long = i64;
 pub type c_ulong = u64;
 pub type time_t = i64;
@@ -29,4 +31,7 @@ s! {
     }
 }
 
+// should be pub(crate), but that requires Rust 1.18.0
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = mem::size_of::<::c_longlong>() - 1;
 pub const MAP_32BIT: ::c_int = 0x00080000;
diff --git a/src/unix/bsd/freebsdlike/freebsd/mod.rs b/src/unix/bsd/freebsdlike/freebsd/mod.rs
index 878deea360..2bc900d321 100644
--- a/src/unix/bsd/freebsdlike/freebsd/mod.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/mod.rs
@@ -1,3 +1,5 @@
+use dox::mem;
+
 pub type fflags_t = u32;
 pub type clock_t = i32;
 pub type ino_t = u32;
@@ -962,7 +964,43 @@ pub const UF_READONLY:  ::c_ulong = 0x00001000;
 pub const UF_HIDDEN:    ::c_ulong = 0x00008000;
 pub const SF_SNAPSHOT:  ::c_ulong = 0x00200000;
 
+fn _ALIGN(p: usize) -> usize {
+    (p + _ALIGNBYTES) & !_ALIGNBYTES
+}
+
 f! {
+    pub fn CMSG_DATA(cmsg: *const ::cmsghdr) -> *mut ::c_uchar {
+        (cmsg as *mut ::c_uchar)
+            .offset(_ALIGN(mem::size_of::<::cmsghdr>()) as isize)
+    }
+
+    pub fn CMSG_LEN(length: ::c_uint) -> ::c_uint {
+        _ALIGN(mem::size_of::<::cmsghdr>()) as ::c_uint + length
+    }
+
+    pub fn CMSG_NXTHDR(mhdr: *const ::msghdr, cmsg: *const ::cmsghdr)
+        -> *mut ::cmsghdr
+    {
+        if cmsg.is_null() {
+            return ::CMSG_FIRSTHDR(mhdr);
+        };
+        let next = cmsg as usize + _ALIGN((*cmsg).cmsg_len as usize)
+            + _ALIGN(mem::size_of::<::cmsghdr>());
+        let max = (*mhdr).msg_control as usize
+            + (*mhdr).msg_controllen as usize;
+        if next > max {
+            0 as *mut ::cmsghdr
+        } else {
+            (cmsg as usize + _ALIGN((*cmsg).cmsg_len as usize))
+                as *mut ::cmsghdr
+        }
+    }
+
+    pub fn CMSG_SPACE(length: ::c_uint) -> ::c_uint {
+        (_ALIGN(mem::size_of::<::cmsghdr>()) + _ALIGN(length as usize))
+            as ::c_uint
+    }
+
     pub fn uname(buf: *mut ::utsname) -> ::c_int {
         __xuname(256, buf as *mut ::c_void)
     }
diff --git a/src/unix/bsd/freebsdlike/freebsd/x86.rs b/src/unix/bsd/freebsdlike/freebsd/x86.rs
index 8a5e5f9fb8..a5495aaaa1 100644
--- a/src/unix/bsd/freebsdlike/freebsd/x86.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/x86.rs
@@ -1,3 +1,5 @@
+use dox::mem;
+
 pub type c_long = i32;
 pub type c_ulong = u32;
 pub type time_t = i32;
@@ -29,3 +31,7 @@ s! {
         __unused: [u8; 8],
     }
 }
+
+// should be pub(crate), but that requires Rust 1.18.0
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = mem::size_of::<::c_long>() - 1;
diff --git a/src/unix/bsd/freebsdlike/freebsd/x86_64.rs b/src/unix/bsd/freebsdlike/freebsd/x86_64.rs
index 3d61f889d8..711feb7222 100644
--- a/src/unix/bsd/freebsdlike/freebsd/x86_64.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/x86_64.rs
@@ -1,3 +1,5 @@
+use dox::mem;
+
 pub type c_long = i64;
 pub type c_ulong = u64;
 pub type time_t = i64;
@@ -29,4 +31,7 @@ s! {
     }
 }
 
+// should be pub(crate), but that requires Rust 1.18.0
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = mem::size_of::<::c_long>() - 1;
 pub const MAP_32BIT: ::c_int = 0x00080000;
diff --git a/src/unix/bsd/mod.rs b/src/unix/bsd/mod.rs
index 23efbe7e2b..12f6e14d93 100644
--- a/src/unix/bsd/mod.rs
+++ b/src/unix/bsd/mod.rs
@@ -342,43 +342,14 @@ pub const POLLRDBAND: ::c_short = 0x080;
 pub const POLLWRBAND: ::c_short = 0x100;
 
 f! {
-    pub fn CMSG_FIRSTHDR(mhdr: *const msghdr) -> *mut cmsghdr {
-        if (*mhdr).msg_controllen as usize >= mem::size_of::<cmsghdr>() {
-            (*mhdr).msg_control as *mut cmsghdr
+    pub fn CMSG_FIRSTHDR(mhdr: *const ::msghdr) -> *mut ::cmsghdr {
+        if (*mhdr).msg_controllen as usize >= mem::size_of::<::cmsghdr>() {
+            (*mhdr).msg_control as *mut ::cmsghdr
         } else {
-            0 as *mut cmsghdr
+            0 as *mut ::cmsghdr
         }
     }
 
-    pub fn CMSG_NXTHDR(mhdr: *const msghdr,
-                       cmsg: *const cmsghdr) -> *mut cmsghdr {
-        if cmsg.is_null() {
-            return CMSG_FIRSTHDR(mhdr);
-        };
-        let pad = mem::align_of::<cmsghdr>() - 1;
-        let next = cmsg as usize + (*cmsg).cmsg_len as usize + pad & !pad;
-        let max = (*mhdr).msg_control as usize
-            + (*mhdr).msg_controllen as usize;
-        if next < max {
-            next as *mut cmsghdr
-        } else {
-            0 as *mut cmsghdr
-        }
-    }
-
-    pub fn CMSG_DATA(cmsg: *const cmsghdr) -> *mut ::c_uchar {
-        cmsg.offset(1) as *mut ::c_uchar
-    }
-
-    pub fn CMSG_SPACE(length: ::c_uint) -> ::c_uint {
-        let pad = mem::align_of::<cmsghdr>() as ::c_uint - 1;
-        mem::size_of::<cmsghdr>() as ::c_uint + ((length + pad) & !pad)
-    }
-
-    pub fn CMSG_LEN(length: ::c_uint) -> ::c_uint {
-        mem::size_of::<cmsghdr>() as ::c_uint + length
-    }
-
     pub fn FD_CLR(fd: ::c_int, set: *mut fd_set) -> () {
         let bits = mem::size_of_val(&(*set).fds_bits[0]) * 8;
         let fd = fd as usize;
diff --git a/src/unix/bsd/netbsdlike/mod.rs b/src/unix/bsd/netbsdlike/mod.rs
index 771818b5f1..291c081b97 100644
--- a/src/unix/bsd/netbsdlike/mod.rs
+++ b/src/unix/bsd/netbsdlike/mod.rs
@@ -1,3 +1,5 @@
+use dox::mem;
+
 pub type time_t = i64;
 pub type mode_t = u32;
 pub type nlink_t = ::uint32_t;
@@ -593,7 +595,43 @@ pub const SF_APPEND:        ::c_ulong = 0x00040000;
 
 pub const TIMER_ABSTIME: ::c_int = 1;
 
+fn _ALIGN(p: usize) -> usize {
+    (p + _ALIGNBYTES) & !_ALIGNBYTES
+}
+
 f! {
+    pub fn CMSG_DATA(cmsg: *const ::cmsghdr) -> *mut ::c_uchar {
+        (cmsg as *mut ::c_uchar)
+            .offset(_ALIGN(mem::size_of::<::cmsghdr>()) as isize)
+    }
+
+    pub fn CMSG_LEN(length: ::c_uint) -> ::c_uint {
+        _ALIGN(mem::size_of::<::cmsghdr>()) as ::c_uint + length
+    }
+
+    pub fn CMSG_NXTHDR(mhdr: *const ::msghdr, cmsg: *const ::cmsghdr)
+        -> *mut ::cmsghdr
+    {
+        if cmsg.is_null() {
+            return ::CMSG_FIRSTHDR(mhdr);
+        };
+        let next = cmsg as usize + _ALIGN((*cmsg).cmsg_len as usize)
+            + _ALIGN(mem::size_of::<::cmsghdr>());
+        let max = (*mhdr).msg_control as usize
+            + (*mhdr).msg_controllen as usize;
+        if next > max {
+            0 as *mut ::cmsghdr
+        } else {
+            (cmsg as usize + _ALIGN((*cmsg).cmsg_len as usize))
+                as *mut ::cmsghdr
+        }
+    }
+
+    pub fn CMSG_SPACE(length: ::c_uint) -> ::c_uint {
+        (_ALIGN(mem::size_of::<::cmsghdr>()) + _ALIGN(length as usize))
+            as ::c_uint
+    }
+
     pub fn WSTOPSIG(status: ::c_int) -> ::c_int {
         status >> 8
     }
diff --git a/src/unix/bsd/netbsdlike/netbsd/aarch64.rs b/src/unix/bsd/netbsdlike/netbsd/aarch64.rs
index 66f33016b1..cda75bc5cd 100644
--- a/src/unix/bsd/netbsdlike/netbsd/aarch64.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/aarch64.rs
@@ -1,3 +1,5 @@
+use dox::mem;
+
 use PT_FIRSTMACH;
 
 pub type c_long = i64;
@@ -5,6 +7,10 @@ pub type c_ulong = u64;
 pub type c_char = u8;
 pub type __cpu_simple_lock_nv_t = ::c_uchar;
 
+// should be pub(crate), but that requires Rust 1.18.0
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = mem::size_of::<::c_int>() - 1;
+
 pub const PT_GETREGS: ::c_int = PT_FIRSTMACH + 0;
 pub const PT_SETREGS: ::c_int = PT_FIRSTMACH + 1;
 pub const PT_GETFPREGS: ::c_int = PT_FIRSTMACH + 2;
diff --git a/src/unix/bsd/netbsdlike/netbsd/arm.rs b/src/unix/bsd/netbsdlike/netbsd/arm.rs
index 9e673166d6..71c2cb7b79 100644
--- a/src/unix/bsd/netbsdlike/netbsd/arm.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/arm.rs
@@ -1,3 +1,5 @@
+use dox::mem;
+
 use PT_FIRSTMACH;
 
 pub type c_long = i32;
@@ -5,6 +7,10 @@ pub type c_ulong = u32;
 pub type c_char = u8;
 pub type __cpu_simple_lock_nv_t = ::c_int;
 
+// should be pub(crate), but that requires Rust 1.18.0
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = mem::size_of::<::c_longlong>() - 1;
+
 pub const PT_GETREGS: ::c_int = PT_FIRSTMACH + 1;
 pub const PT_SETREGS: ::c_int = PT_FIRSTMACH + 2;
 pub const PT_GETFPREGS: ::c_int = PT_FIRSTMACH + 3;
diff --git a/src/unix/bsd/netbsdlike/netbsd/powerpc.rs b/src/unix/bsd/netbsdlike/netbsd/powerpc.rs
index 54d069e607..3c682c35cf 100644
--- a/src/unix/bsd/netbsdlike/netbsd/powerpc.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/powerpc.rs
@@ -1,3 +1,5 @@
+use dox::mem;
+
 use PT_FIRSTMACH;
 
 pub type c_long = i32;
@@ -5,6 +7,10 @@ pub type c_ulong = u32;
 pub type c_char = u8;
 pub type __cpu_simple_lock_nv_t = ::c_int;
 
+// should be pub(crate), but that requires Rust 1.18.0
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = mem::size_of::<::c_double>() - 1;
+
 pub const PT_STEP: ::c_int = PT_FIRSTMACH + 0;
 pub const PT_GETREGS: ::c_int = PT_FIRSTMACH + 1;
 pub const PT_SETREGS: ::c_int = PT_FIRSTMACH + 2;
diff --git a/src/unix/bsd/netbsdlike/netbsd/sparc64.rs b/src/unix/bsd/netbsdlike/netbsd/sparc64.rs
index db8f2a94c5..6a86759e07 100644
--- a/src/unix/bsd/netbsdlike/netbsd/sparc64.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/sparc64.rs
@@ -2,3 +2,7 @@ pub type c_long = i64;
 pub type c_ulong = u64;
 pub type c_char = i8;
 pub type __cpu_simple_lock_nv_t = ::c_uchar;
+
+// should be pub(crate), but that requires Rust 1.18.0
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = 0xf;
diff --git a/src/unix/bsd/netbsdlike/netbsd/x86.rs b/src/unix/bsd/netbsdlike/netbsd/x86.rs
index 8bd105841d..4da99685f9 100644
--- a/src/unix/bsd/netbsdlike/netbsd/x86.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/x86.rs
@@ -1,4 +1,10 @@
+use dox::mem;
+
 pub type c_long = i32;
 pub type c_ulong = u32;
 pub type c_char = i8;
 pub type __cpu_simple_lock_nv_t = ::c_uchar;
+
+// should be pub(crate), but that requires Rust 1.18.0
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = mem::size_of::<::c_int>() - 1;
diff --git a/src/unix/bsd/netbsdlike/netbsd/x86_64.rs b/src/unix/bsd/netbsdlike/netbsd/x86_64.rs
index 8d3de8453a..af1b8f8000 100644
--- a/src/unix/bsd/netbsdlike/netbsd/x86_64.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/x86_64.rs
@@ -1,3 +1,5 @@
+use dox::mem;
+
 use PT_FIRSTMACH;
 
 pub type c_long = i64;
@@ -5,6 +7,10 @@ pub type c_ulong = u64;
 pub type c_char = i8;
 pub type __cpu_simple_lock_nv_t = ::c_uchar;
 
+// should be pub(crate), but that requires Rust 1.18.0
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = mem::size_of::<::c_long>() - 1;
+
 pub const PT_STEP: ::c_int = PT_FIRSTMACH + 0;
 pub const PT_GETREGS: ::c_int = PT_FIRSTMACH + 1;
 pub const PT_SETREGS: ::c_int = PT_FIRSTMACH + 2;
diff --git a/src/unix/bsd/netbsdlike/openbsdlike/openbsd/aarch64.rs b/src/unix/bsd/netbsdlike/openbsdlike/openbsd/aarch64.rs
index 6aa9950ed1..2a28c2a88a 100644
--- a/src/unix/bsd/netbsdlike/openbsdlike/openbsd/aarch64.rs
+++ b/src/unix/bsd/netbsdlike/openbsdlike/openbsd/aarch64.rs
@@ -1,3 +1,9 @@
+use dox::mem;
+
 pub type c_long = i64;
 pub type c_ulong = u64;
 pub type c_char = u8;
+
+// should be pub(crate), but that requires Rust 1.18.0
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = mem::size_of::<::c_long>() - 1;
diff --git a/src/unix/bsd/netbsdlike/openbsdlike/openbsd/x86.rs b/src/unix/bsd/netbsdlike/openbsdlike/openbsd/x86.rs
index a00e3337ef..b63b69fb63 100644
--- a/src/unix/bsd/netbsdlike/openbsdlike/openbsd/x86.rs
+++ b/src/unix/bsd/netbsdlike/openbsdlike/openbsd/x86.rs
@@ -1,3 +1,9 @@
+use dox::mem;
+
 pub type c_long = i32;
 pub type c_ulong = u32;
 pub type c_char = i8;
+
+// should be pub(crate), but that requires Rust 1.18.0
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = mem::size_of::<::c_int>() - 1;
diff --git a/src/unix/bsd/netbsdlike/openbsdlike/openbsd/x86_64.rs b/src/unix/bsd/netbsdlike/openbsdlike/openbsd/x86_64.rs
index 3bc7f52471..581096fdfa 100644
--- a/src/unix/bsd/netbsdlike/openbsdlike/openbsd/x86_64.rs
+++ b/src/unix/bsd/netbsdlike/openbsdlike/openbsd/x86_64.rs
@@ -1,9 +1,15 @@
+use dox::mem;
+
 use PT_FIRSTMACH;
 
 pub type c_long = i64;
 pub type c_ulong = u64;
 pub type c_char = i8;
 
+// should be pub(crate), but that requires Rust 1.18.0
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = mem::size_of::<::c_long>() - 1;
+
 pub const PT_STEP: ::c_int = PT_FIRSTMACH + 0;
 pub const PT_GETREGS: ::c_int = PT_FIRSTMACH + 1;
 pub const PT_SETREGS: ::c_int = PT_FIRSTMACH + 2;