c - recvmsg fails with "Bad Address"

Question

I am trying to receive ancillary data via UNIX domain sockets using the following code.

 struct iovec iov = {
    .iov_base = &app->req,
    .iov_len = sizeof(app->req) - app->req_rx,
  };
  union {
    char buf[CMSG_SPACE(sizeof(int))];
    struct cmsghdr align;
  } u;
  struct msghdr msg = {
    .msg_name = NULL,
    .msg_namelen = 0,
    .msg_iov = &iov,
    .msg_iovlen = 1,
    .msg_control = u.buf,
    .msg_controllen = sizeof(u.buf),
    .msg_flags = 0,
  };
  rx = recvmsg(app->fd, &msg, 0);

Here, recvmsg fails and returns -1, and the reason is "Bad Address". Any reason as to why this might be happening.

question from:https://stackoverflow.com/questions/65932481/recvmsg-fails-with-bad-address

Answer 1

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