linux-user: Support the accept4 socketcall

Cc: Riku Voipio <riku.voipio@iki.fi>
Signed-off-by: André Hentschel <nerv@dawncrow.de>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Erik de Castro Lopo <erikd@mega-nerd.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

linux-user/syscall.c

@@ -2245,6 +2245,22 @@ static abi_long do_socketcall(int num, abi_ulong vptr)
             ret = do_accept4(sockfd, target_addr, target_addrlen, 0);
         }
         break;
+    case SOCKOP_accept4:
+        {
+            abi_ulong sockfd;
+            abi_ulong target_addr, target_addrlen;
+            abi_ulong flags;
+
+            if (get_user_ual(sockfd, vptr)
+                || get_user_ual(target_addr, vptr + n)
+                || get_user_ual(target_addrlen, vptr + 2 * n)
+                || get_user_ual(flags, vptr + 3 * n)) {
+                return -TARGET_EFAULT;
+            }
+
+            ret = do_accept4(sockfd, target_addr, target_addrlen, flags);
+        }
+        break;
     case SOCKOP_getsockname:
         {
             abi_ulong sockfd;

linux-user/syscall_defs.h

@@ -27,6 +27,7 @@
 #define SOCKOP_getsockopt       15
 #define SOCKOP_sendmsg          16
 #define SOCKOP_recvmsg          17
+#define SOCKOP_accept4          18
 
 #define IPCOP_semop		1
 #define IPCOP_semget		2