From: Qian Cai
> Sent: 30 July 2019 15:38
...
> Use an implicit alignment for "struct __kernel_sockaddr_storage" so it
> can keep the same alignments as a member in both packed and un-packed
> structures without breaking UAPI.
>
> Suggested-by: David Laight <David.Laight@xxxxxxxxxx>
...
Although I suggested it needs a bit of tidy up.
Add a comment maybe:
/* The definition uses anonymous union and struct in order to
* control the default alignment. */
> struct __kernel_sockaddr_storage {
> - __kernel_sa_family_t ss_family; /* address family */
> - /* Following field(s) are implementation specific */
> - char __data[_K_SS_MAXSIZE - sizeof(unsigned short)];
> + union {
> + void *__align; /* implementation specific desired alignment */
Move the 'void *' below the struct so the first member is the 'public one.
> + struct {
> + __kernel_sa_family_t ss_family; /* address family */
> + /* Following field(s) are implementation specific */
> + char __data[_K_SS_MAXSIZE - sizeof(unsigned short)];
> /* space to achieve desired size, */
> /* _SS_MAXSIZE value minus size of ss_family */
> -} __attribute__ ((aligned(_K_SS_ALIGNSIZE))); /* force desired alignment */
> + };
> + };
> +};
>
> #endif /* _UAPI_LINUX_SOCKET_H */
> --
> 1.8.3.1
David
-
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