[PATCH 0/2] MR5267: ntdll, server: Remove support for msg_accrights FD passing.

[Brendan Shanks (＠bshanks)]

`msghdr.msg_accrights` was the [4.3BSD mechanism](https://man.freebsd.org/cgi/man.cgi?query=recv&apropos=0&sektion=2&a...) for passing FDs over a Unix domain socket, it's now long obsolete.
The only recent OS where it's still available is Solaris, but that's also supported `msg_control` for decades (although additional `#defines` were required pre-11.4).

[PATCH 1/2] ntdll: Remove support for msg_accrights FD passing.

[Brendan Shanks]

From: Brendan Shanks

---
 dlls/ntdll/unix/server.c | 44 +++++++++++++++-------------------------
 dlls/ntdll/unix/socket.c | 14 +------------
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/dlls/ntdll/unix/server.c b/dlls/ntdll/unix/server.c
index 88ac9551060..c1ee8e27f0c 100644
--- a/dlls/ntdll/unix/server.c
+++ b/dlls/ntdll/unix/server.c
@@ -872,29 +872,17 @@ void wine_server_send_fd( int fd )
     struct send_fd data;
     struct msghdr msghdr;
     struct iovec vec;
-    int ret;
-
-#ifdef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
-    msghdr.msg_accrights    = (void *)&fd;
-    msghdr.msg_accrightslen = sizeof(fd);
-#else  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */
     char cmsg_buffer[256];
     struct cmsghdr *cmsg;
-    msghdr.msg_control    = cmsg_buffer;
-    msghdr.msg_controllen = sizeof(cmsg_buffer);
-    msghdr.msg_flags      = 0;
-    cmsg = CMSG_FIRSTHDR( &msghdr );
-    cmsg->cmsg_len   = CMSG_LEN( sizeof(fd) );
-    cmsg->cmsg_level = SOL_SOCKET;
-    cmsg->cmsg_type  = SCM_RIGHTS;
-    *(int *)CMSG_DATA(cmsg) = fd;
-    msghdr.msg_controllen = cmsg->cmsg_len;
-#endif  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */
+    int ret;

msghdr.msg_name    = NULL;
     msghdr.msg_namelen = 0;
     msghdr.msg_iov     = &vec;
     msghdr.msg_iovlen  = 1;
+    msghdr.msg_control = cmsg_buffer;
+    msghdr.msg_controllen = sizeof(cmsg_buffer);
+    msghdr.msg_flags   = 0;

vec.iov_base = (void *)&data;
     vec.iov_len  = sizeof(data);
@@ -902,6 +890,13 @@ void wine_server_send_fd( int fd )
     data.tid = GetCurrentThreadId();
     data.fd  = fd;

+    cmsg = CMSG_FIRSTHDR( &msghdr );
+    cmsg->cmsg_len   = CMSG_LEN( sizeof(fd) );
+    cmsg->cmsg_level = SOL_SOCKET;
+    cmsg->cmsg_type  = SCM_RIGHTS;
+    *(int *)CMSG_DATA(cmsg) = fd;
+    msghdr.msg_controllen = cmsg->cmsg_len;
+
     for (;;)
     {
         if ((ret = sendmsg( fd_socket, &msghdr, 0 )) == sizeof(data)) return;
@@ -922,22 +917,17 @@ static int receive_fd( obj_handle_t *handle )
 {
     struct iovec vec;
     struct msghdr msghdr;
-    int ret, fd = -1;
-
-#ifdef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
-    msghdr.msg_accrights    = (void *)&fd;
-    msghdr.msg_accrightslen = sizeof(fd);
-#else  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */
     char cmsg_buffer[256];
-    msghdr.msg_control    = cmsg_buffer;
-    msghdr.msg_controllen = sizeof(cmsg_buffer);
-    msghdr.msg_flags      = 0;
-#endif  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */
+    int ret, fd = -1;

msghdr.msg_name    = NULL;
     msghdr.msg_namelen = 0;
     msghdr.msg_iov     = &vec;
     msghdr.msg_iovlen  = 1;
+    msghdr.msg_control = cmsg_buffer;
+    msghdr.msg_controllen = sizeof(cmsg_buffer);
+    msghdr.msg_flags   = 0;
+
     vec.iov_base = (void *)handle;
     vec.iov_len  = sizeof(*handle);

@@ -945,7 +935,6 @@ static int receive_fd( obj_handle_t *handle )
     {
         if ((ret = recvmsg( fd_socket, &msghdr, MSG_CMSG_CLOEXEC )) > 0)
         {
-#ifndef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
             struct cmsghdr *cmsg;
             for (cmsg = CMSG_FIRSTHDR( &msghdr ); cmsg; cmsg = CMSG_NXTHDR( &msghdr, cmsg ))
             {
@@ -959,7 +948,6 @@ static int receive_fd( obj_handle_t *handle )
                 }
 #endif
             }
-#endif  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */
             if (fd != -1) fcntl( fd, F_SETFD, FD_CLOEXEC ); /* in case MSG_CMSG_CLOEXEC is not supported */
             return fd;
         }
diff --git a/dlls/ntdll/unix/socket.c b/dlls/ntdll/unix/socket.c
index 4b0dca37e7d..65f30759db3 100644
--- a/dlls/ntdll/unix/socket.c
+++ b/dlls/ntdll/unix/socket.c
@@ -371,7 +371,6 @@ static int sockaddr_from_unix( const union unix_sockaddr *uaddr, struct WS_socka
     }
 }

-#ifndef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
 static WSACMSGHDR *fill_control_message( int level, int type, WSACMSGHDR *current, ULONG *maxsize, void *data, int len )
 {
     ULONG msgsize = sizeof(WSACMSGHDR) + WSA_CMSG_ALIGN(len);
@@ -513,14 +512,6 @@ error:
     control->len = 0;
     return 0;
 }
-#else
-static int convert_control_headers(struct msghdr *hdr, WSABUF *control)
-{
-    ERR( "Message control headers cannot be properly supported on this system.\n" );
-    control->len = 0;
-    return 0;
-}
-#endif /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */

struct cmsghdr_32
 {
@@ -721,9 +712,7 @@ static ssize_t fixup_icmp_over_dgram( struct msghdr *hdr, union unix_sockaddr *u

static NTSTATUS try_recv( int fd, struct async_recv_ioctl *async, ULONG_PTR *size )
 {
-#ifndef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
     char control_buffer[512];
-#endif
     union unix_sockaddr unix_addr;
     struct msghdr hdr;
     NTSTATUS status;
@@ -737,10 +726,9 @@ static NTSTATUS try_recv( int fd, struct async_recv_ioctl *async, ULONG_PTR *siz
     }
     hdr.msg_iov = async->iov;
     hdr.msg_iovlen = async->count;
-#ifndef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
     hdr.msg_control = control_buffer;
     hdr.msg_controllen = sizeof(control_buffer);
-#endif
+
     while ((ret = virtual_locked_recvmsg( fd, &hdr, async->unix_flags )) < 0 && errno == EINTR);

if (ret < 0)

[PATCH 2/2] server: Remove support for msg_accrights FD passing.

[Brendan Shanks]

From: Brendan Shanks

---
 configure.ac     |  2 +-
 server/request.c | 44 ++++++++++++++++----------------------------
 2 files changed, 17 insertions(+), 29 deletions(-)

diff --git a/configure.ac b/configure.ac
index 417b1a63a13..07a832c0b6f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2163,7 +2163,7 @@ AC_CACHE_CHECK([whether we can use re-entrant gethostbyname_r Linux style],
    fi

dnl Check for socket structure members
-AC_CHECK_MEMBERS([struct msghdr.msg_accrights, struct sockaddr_un.sun_len],,,
+AC_CHECK_MEMBERS([struct sockaddr_un.sun_len],,,
 [#include <sys/types.h>
 #include <sys/socket.h>
 #ifdef HAVE_SYS_UN_H
diff --git a/server/request.c b/server/request.c
index 7021741c765..82b4a722d61 100644
--- a/server/request.c
+++ b/server/request.c
@@ -379,28 +379,22 @@ int receive_fd( struct process *process )
     struct iovec vec;
     struct send_fd data;
     struct msghdr msghdr;
-    int fd = -1, ret;
-
-#ifdef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
-    msghdr.msg_accrightslen = sizeof(int);
-    msghdr.msg_accrights = (void *)&fd;
-#else  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */
     char cmsg_buffer[256];
-    msghdr.msg_control    = cmsg_buffer;
-    msghdr.msg_controllen = sizeof(cmsg_buffer);
-    msghdr.msg_flags      = 0;
-#endif  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */
+    int fd = -1, ret;

msghdr.msg_name    = NULL;
     msghdr.msg_namelen = 0;
     msghdr.msg_iov     = &vec;
     msghdr.msg_iovlen  = 1;
+    msghdr.msg_control = cmsg_buffer;
+    msghdr.msg_controllen = sizeof(cmsg_buffer);
+    msghdr.msg_flags   = 0;
+
     vec.iov_base = (void *)&data;
     vec.iov_len  = sizeof(data);

ret = recvmsg( get_unix_fd( process->msg_fd ), &msghdr, 0 );

-#ifndef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
     if (ret > 0)
     {
         struct cmsghdr *cmsg;
@@ -410,7 +404,6 @@ int receive_fd( struct process *process )
             if (cmsg->cmsg_type == SCM_RIGHTS) fd = *(int *)CMSG_DATA(cmsg);
         }
     }
-#endif  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */

if (ret == sizeof(data))
     {
@@ -465,33 +458,28 @@ int send_client_fd( struct process *process, int fd, obj_handle_t handle )
 {
     struct iovec vec;
     struct msghdr msghdr;
-    int ret;
-
-#ifdef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
-    msghdr.msg_accrightslen = sizeof(fd);
-    msghdr.msg_accrights = (void *)&fd;
-#else  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */
     char cmsg_buffer[256];
     struct cmsghdr *cmsg;
-    msghdr.msg_control    = cmsg_buffer;
-    msghdr.msg_controllen = sizeof(cmsg_buffer);
-    msghdr.msg_flags      = 0;
-    cmsg = CMSG_FIRSTHDR( &msghdr );
-    cmsg->cmsg_len   = CMSG_LEN( sizeof(fd) );
-    cmsg->cmsg_level = SOL_SOCKET;
-    cmsg->cmsg_type  = SCM_RIGHTS;
-    *(int *)CMSG_DATA(cmsg) = fd;
-    msghdr.msg_controllen = cmsg->cmsg_len;
-#endif  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */
+    int ret;

msghdr.msg_name    = NULL;
     msghdr.msg_namelen = 0;
     msghdr.msg_iov     = &vec;
     msghdr.msg_iovlen  = 1;
+    msghdr.msg_control = cmsg_buffer;
+    msghdr.msg_controllen = sizeof(cmsg_buffer);
+    msghdr.msg_flags   = 0;

vec.iov_base = (void *)&handle;
     vec.iov_len  = sizeof(handle);

+    cmsg = CMSG_FIRSTHDR( &msghdr );
+    cmsg->cmsg_len   = CMSG_LEN( sizeof(fd) );
+    cmsg->cmsg_level = SOL_SOCKET;
+    cmsg->cmsg_type  = SCM_RIGHTS;
+    *(int *)CMSG_DATA(cmsg) = fd;
+    msghdr.msg_controllen = cmsg->cmsg_len;
+
     if (debug_level)
         fprintf( stderr, "%04x: *fd* %04x -> %d\n", current ? current->id : process->id, handle, fd );