musl: Switch to the new structure for socket.h

Move `struct msghdr`, `struct cmsghdr`, `sendmmsg`, and `recvmmsg` over
at this time, as well as two `SOCK_*` constants that were in the musl
module.

Link: https://github.com/kraj/musl/blob/9f204467e88c75e36105d1359951c5857c20fe0b/include/sys/socket.h

(backport <#4539>)
(cherry picked from commit 564e0ef)

Author: tgross35

src/new/mod.rs

@@ -150,6 +150,7 @@ cfg_if! {
         mod glibc;
         pub(crate) use glibc::*;
     } else if #[cfg(any(target_env = "musl", target_env = "ohos"))] {
+        // OhOS also uses the musl libc
         mod musl;
         pub(crate) use musl::*;
     } else if #[cfg(target_env = "newlib")] {
@@ -167,7 +168,7 @@ cfg_if! {
     }
 }
 
-// Headers we export
+// Per-OS headers we export
 cfg_if! {
     if #[cfg(target_os = "android")] {
         pub use sys::socket::*;
@@ -184,5 +185,12 @@ cfg_if! {
     }
 }
 
+// Per-env headers we export
+cfg_if! {
+    if #[cfg(any(target_env = "musl", target_env = "ohos"))] {
+        pub use sys::socket::*;
+    }
+}
+
 #[cfg(target_family = "unix")]
 pub use unistd::*;

src/new/musl/arch/generic/mod.rs

@@ -0,0 +1,7 @@
+//! Source directory: `arch/generic/`
+//!
+//! <https://github.com/kraj/musl/tree/master/arch/generic>
+
+pub(crate) mod bits {
+    // Currently unused
+}

src/new/musl/arch/mips/bits/socket.rs

@@ -0,0 +1,4 @@
+use crate::prelude::*;
+
+pub const SOCK_STREAM: c_int = 2;
+pub const SOCK_DGRAM: c_int = 1;

src/new/musl/arch/mips/mod.rs

@@ -0,0 +1,7 @@
+//! Source directory: `arch/mips/`
+//!
+//! <https://github.com/kraj/musl/tree/master/arch/mips>
+
+pub(crate) mod bits {
+    pub(crate) mod socket;
+}

src/new/musl/arch/mips64/bits/socket.rs

@@ -0,0 +1,4 @@
+use crate::prelude::*;
+
+pub const SOCK_STREAM: c_int = 2;
+pub const SOCK_DGRAM: c_int = 1;

src/new/musl/arch/mips64/mod.rs

@@ -0,0 +1,7 @@
+//! Source directory: `arch/mips64/`
+//!
+//! <https://github.com/kraj/musl/tree/master/arch/mips64>
+
+pub(crate) mod bits {
+    pub(crate) mod socket;
+}

src/new/musl/arch/mod.rs

@@ -0,0 +1,10 @@
+//! Source directory: `arch/`
+//!
+//! <https://github.com/kraj/musl/tree/master/arch>
+
+pub(crate) mod generic;
+
+#[cfg(target_arch = "mips")]
+pub(crate) mod mips;
+#[cfg(target_arch = "mips64")]
+pub(crate) mod mips64;

src/new/musl/mod.rs

@@ -3,4 +3,28 @@
 //! * Headers: <https://git.musl-libc.org/cgit/musl> (official)
 //! * Headers: <https://github.com/kraj/musl> (mirror)
 
+// The musl build system includes `arch/$(ARCH)` (preferred if it exists) and `arch/generic` (used
+// as the fallback). We can't exactly mirror this with glob exports, so instead we selectively
+// reexport in a new module.
+mod arch;
+
+pub(crate) mod bits {
+    cfg_if! {
+        if #[cfg(target_arch = "mips")] {
+            pub(crate) use super::arch::mips::bits::socket;
+        } else if #[cfg(target_arch = "mips64")] {
+            pub(crate) use super::arch::mips64::bits::socket;
+        } else {
+            // Reexports from generic will live here once we need them.
+        }
+    }
+}
+
+/// Directory: `sys/`
+///
+/// <https://github.com/kraj/musl/tree/kraj/master/include/sys>
+pub(crate) mod sys {
+    pub(crate) mod socket;
+}
+
 pub(crate) mod unistd;

src/new/musl/sys/socket.rs

@@ -0,0 +1,63 @@
+//! Header: `sys/socket.h`
+//!
+//! <https://github.com/kraj/musl/blob/kraj/master/include/sys/socket.h>
+
+use crate::prelude::*;
+
+s! {
+    pub struct msghdr {
+        pub msg_name: *mut c_void,
+        pub msg_namelen: crate::socklen_t,
+        pub msg_iov: *mut crate::iovec,
+        #[cfg(all(target_pointer_width = "64", target_endian = "big"))]
+        __pad1: c_int,
+        pub msg_iovlen: c_int,
+        #[cfg(all(target_pointer_width = "64", target_endian = "little"))]
+        __pad1: c_int,
+        pub msg_control: *mut c_void,
+        #[cfg(all(target_pointer_width = "64", target_endian = "big"))]
+        __pad2: c_int,
+        pub msg_controllen: crate::socklen_t,
+        #[cfg(all(target_pointer_width = "64", target_endian = "little"))]
+        __pad2: c_int,
+        pub msg_flags: c_int,
+    }
+
+    pub struct cmsghdr {
+        #[cfg(all(target_pointer_width = "64", target_endian = "big"))]
+        pub __pad1: c_int,
+        pub cmsg_len: crate::socklen_t,
+        #[cfg(all(target_pointer_width = "64", target_endian = "little"))]
+        pub __pad1: c_int,
+        pub cmsg_level: c_int,
+        pub cmsg_type: c_int,
+    }
+}
+
+extern "C" {
+    pub fn sendmmsg(
+        sockfd: c_int,
+        msgvec: *mut crate::mmsghdr,
+        vlen: c_uint,
+        flags: c_uint,
+    ) -> c_int;
+    pub fn recvmmsg(
+        sockfd: c_int,
+        msgvec: *mut crate::mmsghdr,
+        vlen: c_uint,
+        flags: c_uint,
+        timeout: *mut crate::timespec,
+    ) -> c_int;
+}
+
+cfg_if! {
+    if #[cfg(any(target_arch = "mips", target_arch = "mips64"))] {
+        pub use crate::bits::socket::{
+            SOCK_DGRAM,
+            SOCK_STREAM,
+        };
+    } else {
+        pub const SOCK_STREAM: c_int = 1;
+        pub const SOCK_DGRAM: c_int = 2;
+    }
+}

src/unix/linux_like/linux/mod.rs

@@ -5739,16 +5739,20 @@ f! {
         return ((len) + NLA_ALIGNTO - 1) & !(NLA_ALIGNTO - 1);
     }
 
-    pub fn CMSG_NXTHDR(mhdr: *const msghdr, cmsg: *const cmsghdr) -> *mut cmsghdr {
-        if ((*cmsg).cmsg_len as usize) < size_of::<cmsghdr>() {
-            return core::ptr::null_mut::<cmsghdr>();
+    pub fn CMSG_NXTHDR(
+        mhdr: *const crate::msghdr,
+        cmsg: *const crate::cmsghdr,
+    ) -> *mut crate::cmsghdr {
+        if ((*cmsg).cmsg_len as usize) < size_of::<crate::cmsghdr>() {
+            return core::ptr::null_mut::<crate::cmsghdr>();
         }
-        let next = (cmsg as usize + super::CMSG_ALIGN((*cmsg).cmsg_len as usize)) as *mut cmsghdr;
+        let next =
+            (cmsg as usize + super::CMSG_ALIGN((*cmsg).cmsg_len as usize)) as *mut crate::cmsghdr;
         let max = (*mhdr).msg_control as usize + (*mhdr).msg_controllen as usize;
         if (next.wrapping_offset(1)) as usize > max
             || next as usize + super::CMSG_ALIGN((*next).cmsg_len as usize) > max
         {
-            core::ptr::null_mut::<cmsghdr>()
+            core::ptr::null_mut::<crate::cmsghdr>()
         } else {
             next
         }