On Tue, Oct 15, 2024 at 06:32:43PM -0600, Gustavo A. R. Silva wrote: > -Wflex-array-member-not-at-end was introduced in GCC-14, and we are > getting ready to enable it, globally. > > Address the following warnings by changing the type of the middle struct > members in a couple of composite structs, which are currently causing > trouble, from `struct sockaddr` to `struct sockaddr_legacy`. Note that > the latter struct doesn't contain a flexible-array member. > > include/uapi/linux/if_arp.h:118:25: warning: structure containing a flexible > array member is not at the end of another structure > [-Wflex-array-member-not-at-end] > include/uapi/linux/if_arp.h:119:25: warning: structure containing a flexible > array member is not at the end of another structure > [-Wflex-array-member-not-at-end] > include/uapi/linux/if_arp.h:121:25: warning: structure containing a flexible > array member is not at the end of another structure > [-Wflex-array-member-not-at-end] > include/uapi/linux/if_arp.h:126:25: warning: structure containing a flexible > array member is not at the end of another structure > [-Wflex-array-member-not-at-end] > include/uapi/linux/if_arp.h:127:25: warning: structure containing a flexible > array member is not at the end of another structure > [-Wflex-array-member-not-at-end] > > Also, update some related code, accordingly. > > No binary differences are present after these changes.
These are clearly UAPI files. It would be good to state in the commit message why this is a safe change, at the source level. Could user space code expect the type struct sockaddr and we are going to get warnings when struct sockaddr_legacy is found? Have you tried compiling an old arp binary, one that uses the IOCTL? The netfilter code also references it: http://charette.no-ip.com:81/programming/doxygen/netfilter/structarpreq.html You also need to submit a patch to the man page: https://man7.org/linux/man-pages/man7/arp.7.html You might also want to build some Rust code: https://docs.diesel.rs/master/libc/struct.arpreq.html I've no idea what Rust does when a C structure has a type change. Andrew
