selftest: af_unix: Silence -Wflex-array-member-not-at-end warning for scm_inq.c.

scm_inq.c has no problem in functionality, but when compiled with
-Wflex-array-member-not-at-end, it shows this warning:

scm_inq.c:15:24: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
   15 |         struct cmsghdr cmsghdr;
      |                        ^~~~~~~

Let's silence it.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250811215432.3379570-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/tools/testing/selftests/net/af_unix/scm_inq.c b/tools/testing/selftests/net/af_unix/scm_inq.c
index 9d22561e7b8f3256c66c99a4c081225c903480db..fc467714387ec00bc5bee44d5734276c8d88f097 100644 (file)
--- a/tools/testing/selftests/net/af_unix/scm_inq.c
+++ b/tools/testing/selftests/net/af_unix/scm_inq.c
@@ -11,11 +11,6 @@
 #define NR_CHUNKS      100
 #define MSG_LEN                256
 
-struct scm_inq {
-       struct cmsghdr cmsghdr;
-       int inq;
-};
-
 FIXTURE(scm_inq)
 {
        int fd[2];
@@ -70,35 +65,38 @@ static void send_chunks(struct __test_metadata *_metadata,
 static void recv_chunks(struct __test_metadata *_metadata,
                        FIXTURE_DATA(scm_inq) *self)
 {
+       char cmsg_buf[CMSG_SPACE(sizeof(int))];
        struct msghdr msg = {};
        struct iovec iov = {};
-       struct scm_inq cmsg;
+       struct cmsghdr *cmsg;
        char buf[MSG_LEN];
        int i, ret;
        int inq;
 
        msg.msg_iov = &iov;
        msg.msg_iovlen = 1;
-       msg.msg_control = &cmsg;
-       msg.msg_controllen = CMSG_SPACE(sizeof(cmsg.inq));
+       msg.msg_control = cmsg_buf;
+       msg.msg_controllen = sizeof(cmsg_buf);
 
        iov.iov_base = buf;
        iov.iov_len = sizeof(buf);
 
        for (i = 0; i < NR_CHUNKS; i++) {
                memset(buf, 0, sizeof(buf));
-               memset(&cmsg, 0, sizeof(cmsg));
+               memset(cmsg_buf, 0, sizeof(cmsg_buf));
 
                ret = recvmsg(self->fd[1], &msg, 0);
                ASSERT_EQ(MSG_LEN, ret);
-               ASSERT_NE(NULL, CMSG_FIRSTHDR(&msg));
-               ASSERT_EQ(CMSG_LEN(sizeof(cmsg.inq)), cmsg.cmsghdr.cmsg_len);
-               ASSERT_EQ(SOL_SOCKET, cmsg.cmsghdr.cmsg_level);
-               ASSERT_EQ(SCM_INQ, cmsg.cmsghdr.cmsg_type);
+
+               cmsg = CMSG_FIRSTHDR(&msg);
+               ASSERT_NE(NULL, cmsg);
+               ASSERT_EQ(CMSG_LEN(sizeof(int)), cmsg->cmsg_len);
+               ASSERT_EQ(SOL_SOCKET, cmsg->cmsg_level);
+               ASSERT_EQ(SCM_INQ, cmsg->cmsg_type);
 
                ret = ioctl(self->fd[1], SIOCINQ, &inq);
                ASSERT_EQ(0, ret);
-               ASSERT_EQ(cmsg.inq, inq);
+               ASSERT_EQ(*(int *)CMSG_DATA(cmsg), inq);
        }
 }