Re: [hurd-amd64] ibus test failures

[Diego Nieto Cid]

On Tue, Dec 31, 2024 at 04:01:08PM +0000, Diego Nieto Cid wrote:
> 
> Ok, I'll have a look in both OSes behaviour.

There's something wrong with our CMSG_DATA macro. It produces the wrong 
output (or at least different from Linux).

The attached program prints:

    cmsg: 0x101040a90; data: 0x101040a9c; hurd=0x101040a9c, linux=0x101040aa0

data seems to be off by 4 bytes compared to linux output.

#include <stdio.h>
#include <sys/socket.h>

int main(int argc, char **argv)
{

  size_t ucred = 12;
  printf("ucred: %lu\n", ucred);
  printf("CMS_LEN(ucred): %lu\n", CMSG_LEN(ucred));

  size_t cmsgcred = 84;
  printf("cmsgcred: %lu\n", cmsgcred);
  printf("CMS_LEN(cmsgcred): %lu\n", CMSG_LEN(cmsgcred));

  struct cmsghdr *cmsg = (struct cmsghdr *) 0x101040a90;
  printf("cmsg: %p; data: %p; hurd=0x101040a9c, linux=0x101040aa0\n", cmsg, CMSG_DATA(cmsg));

  return 0;
}