On Tue, Dec 31, 2024 at 02:02:53AM +0000, Diego Nieto Cid wrote:
>
> Here are the results for `hurd-amd64`:
>
> $ cc -I/usr/include/glib-2.0 -I/usr/lib/x86_64-gnu/glib-2.0/include \
> -pthread cred_size.c -lgio-2.0 -lgobject-2.0 -lglib-2.0 \
> -o cred_size
>
> $ ./cred_size
> sizeof (int): 4
> sizeof(struct cmsgcred): 84
> CMSG_LEN(sizeof (int)): 20
> CMSG_LEN(g_socket_control_message_get_size (scm)): 100
>
> and here the results for `hurd-i386`:
>
> $ ./cred_size
> sizeof (int): 4
> sizeof(struct cmsgcred): 84
> CMSG_LEN(sizeof (int)): 16
> CMSG_LEN(g_socket_control_message_get_size (scm)): 96
>
I think the usage of size_t is what breaks the computation on
hurd-amd64 (8 bytes while on i386 is 4):
#define CMSG_ALIGN(len) (((len) + sizeof (size_t) - 1) \
& (size_t) ~(sizeof (size_t) - 1))
#define CMSG_SPACE(len) (CMSG_ALIGN (len) \
+ CMSG_ALIGN (sizeof (struct cmsghdr)))
#define CMSG_LEN(len) (CMSG_ALIGN (sizeof (struct cmsghdr)) + (len))
I'm not sure how to fix it. Should the expectations of GLib be updated
to be aligned? Like below:
- if (size != G_CREDENTIALS_NATIVE_SIZE)
+ if (size != CMSG_ALIGN(G_CREDENTIALS_NATIVE_SIZE))
Or should the macros be updated to use a 4 bytes size_t equivalent?
