Hi Philipp,
On Sat, 20 Feb 2021 at 16:25, Philipp Schuster <phip1611@xxxxxxxxx> wrote:
>
> To whom it may concern,
> I'd like to inform you about a bug in the Netlink(7) man page [0].
>
> It describes struct nlmsgerr the following way:
>
> struct nlmsgerr {
> int error; /* Negative errno or 0 for acknowledgements */
> struct nlmsghdr msg; /* Message header that caused the error */
> };
>
> but according to Kernel code [1] [2] [3] it actually should be:
>
> struct nlmsgerr {
> int error; /* Negative errno or 0 for acknowledgements */
> struct nlmsghdr msg; /* Message header that caused the error */
> /*
> * followed by the message contents unless NETLINK_CAP_ACK was set
> * or the ACK indicates success (error == 0)
> * message length is aligned with NLMSG_ALIGN()
> */
> /*
> * followed by TLVs defined in enum nlmsgerr_attrs
> * if NETLINK_EXT_ACK was set
> */
> };
>
> This discrepancy led to errors implementing at least a Rust library which
> made wrong assumptions about the returned value.
I'm a little unclear. Do you mean that the manual page should include
the additional comments?
Thanks,
Michael
> [0] https://man7.org/linux/man-pages/man7/netlink.7.html
> [1] https://elixir.bootlin.com/linux/v5.11/source/include/uapi/linux/netlink.h#L112
> [2] https://elixir.bootlin.com/linux/v5.11/source/net/netlink/af_netlink.c#L2416
> [3] https://elixir.bootlin.com/linux/v5.11/source/net/netlink/af_netlink.c#L2440
>
>
> Kind regards
> --
> Philipp Schuster
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
