linux-user: Implement accept4

Implement the accept4 syscall (which is identical to accept
but has an additional flags argument).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

1 files changed, 31 insertions, 8 deletions

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 77281f1..6182a27 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -2004,16 +2004,30 @@ out2:
     return ret;
 }
 
-/* do_accept() Must return target values and target errnos. */
-static abi_long do_accept(int fd, abi_ulong target_addr,
-                          abi_ulong target_addrlen_addr)
+/* If we don't have a system accept4() then just call accept.
+ * The callsites to do_accept4() will ensure that they don't
+ * pass a non-zero flags argument in this config.
+ */
+#ifndef CONFIG_ACCEPT4
+static inline int accept4(int sockfd, struct sockaddr *addr,
+                          socklen_t *addrlen, int flags)
+{
+    assert(flags == 0);
+    return accept(sockfd, addr, addrlen);
+}
+#endif
+
+/* do_accept4() Must return target values and target errnos. */
+static abi_long do_accept4(int fd, abi_ulong target_addr,
+                           abi_ulong target_addrlen_addr, int flags)
 {
     socklen_t addrlen;
     void *addr;
     abi_long ret;
 
-    if (target_addr == 0)
-       return get_errno(accept(fd, NULL, NULL));
+    if (target_addr == 0) {
+        return get_errno(accept4(fd, NULL, NULL, flags));
+    }
 
     /* linux returns EINVAL if addrlen pointer is invalid */
     if (get_user_u32(addrlen, target_addrlen_addr))
@@ -2028,7 +2042,7 @@ static abi_long do_accept(int fd, abi_ulong target_addr,
 
     addr = alloca(addrlen);
 
-    ret = get_errno(accept(fd, addr, &addrlen));
+    ret = get_errno(accept4(fd, addr, &addrlen, flags));
     if (!is_error(ret)) {
         host_to_target_sockaddr(target_addr, addr, addrlen);
         if (put_user_u32(addrlen, target_addrlen_addr))
@@ -2254,7 +2268,7 @@ static abi_long do_socketcall(int num, abi_ulong vptr)
                 || get_user_ual(target_addrlen, vptr + 2 * n))
                 return -TARGET_EFAULT;
 
-            ret = do_accept(sockfd, target_addr, target_addrlen);
+            ret = do_accept4(sockfd, target_addr, target_addrlen, 0);
         }
         break;
     case SOCKOP_getsockname:
@@ -6677,7 +6691,16 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
 #endif
 #ifdef TARGET_NR_accept
     case TARGET_NR_accept:
-        ret = do_accept(arg1, arg2, arg3);
+        ret = do_accept4(arg1, arg2, arg3, 0);
+        break;
+#endif
+#ifdef TARGET_NR_accept4
+    case TARGET_NR_accept4:
+#ifdef CONFIG_ACCEPT4
+        ret = do_accept4(arg1, arg2, arg3, arg4);
+#else
+        goto unimplemented;
+#endif
         break;
 #endif
 #ifdef TARGET_NR_bind