[10/13] Installed-header hygiene (BZ#20366): struct ether_addr.

  Some versions of netinet/if_ether.h only define struct ether_addr when
__USE_MISC.  This breaks function prototypes in netinet/ether.h that
depend on it.  The path of least resistance is to condition those
declarations on __USE_MISC too.

	* inet/netinet/if_ether.h: Condition all function prototypes
        on __USE_MISC, to ensure struct ether_addr is declared.
---
 inet/netinet/ether.h | 2 ++
 1 file changed, 2 insertions(+)
  

On 08/29/2016 09:16 PM, Zack Weinberg wrote:
> Some versions of netinet/if_ether.h only define struct ether_addr when
> __USE_MISC.  This breaks function prototypes in netinet/ether.h that
> depend on it.  The path of least resistance is to condition those
> declarations on __USE_MISC too.
> 
> 	* inet/netinet/if_ether.h: Condition all function prototypes
>         on __USE_MISC, to ensure struct ether_addr is declared.

You need to explain this in more detail please.

A quick review shows struct ether_addr is not guarded by __USE_MISC
e.g.
sysdeps/generic/netinet/if_ether.h
sysdeps/unix/sysv/linux/net/ethernet.h

Under exactly what conditions is this cleaning up the headers?

> ---
>  inet/netinet/ether.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/inet/netinet/ether.h b/inet/netinet/ether.h
> index 3dff523..0952b23 100644
> --- a/inet/netinet/ether.h
> +++ b/inet/netinet/ether.h
> @@ -24,6 +24,7 @@
>  /* Get definition of `struct ether_addr'.  */
>  #include <netinet/if_ether.h>
>  
> +#ifdef __USE_MISC
>  __BEGIN_DECLS
>  
>  /* Convert 48 bit Ethernet ADDRess to ASCII.  */
> @@ -49,5 +50,6 @@ extern int ether_line (const char *__line, struct ether_addr *__addr,
>  		       char *__hostname) __THROW;
>  
>  __END_DECLS
> +#endif /* Use misc.  */
>  
>  #endif /* netinet/ether.h */
>
  

On 08/29/2016 09:16 PM, Zack Weinberg wrote:
> Some versions of netinet/if_ether.h only define struct ether_addr when
> __USE_MISC.  This breaks function prototypes in netinet/ether.h that
> depend on it.  The path of least resistance is to condition those
> declarations on __USE_MISC too.
> 
> 	* inet/netinet/if_ether.h: Condition all function prototypes
>         on __USE_MISC, to ensure struct ether_addr is declared.

Wrong ChangeLog path?

LGTM.

Linux does define an if_ether.h, but it uses struct ethhdr instead which
doesn't conflict.
  

On Wed, Sep 21, 2016 at 3:51 PM, Carlos O'Donell <carlos@redhat.com> wrote:
> On 08/29/2016 09:16 PM, Zack Weinberg wrote:
>> Some versions of netinet/if_ether.h only define struct ether_addr when
>> __USE_MISC.  This breaks function prototypes in netinet/ether.h that
>> depend on it.  The path of least resistance is to condition those
>> declarations on __USE_MISC too.
>>
>>       * inet/netinet/if_ether.h: Condition all function prototypes
>>         on __USE_MISC, to ensure struct ether_addr is declared.
>
> Wrong ChangeLog path?

Yes, that should've been inet/netinet/ether.h.

You may have already figured this out for yourself, but for the
record: There are two versions of netinet/if_ether.h in the tree:

./sysdeps/generic/netinet/if_ether.h
./sysdeps/unix/sysv/linux/netinet/if_ether.h

(There is also sysdeps/mach/hurd/net/if_ether.h but that appears to be
an unrelated header - note it's in net/ instead of netinet/ - it
defines approximately the same things that uapi <linux/if_ether.h>
does.)

The generic netinet/if_ether.h defines struct ether_addr
unconditionally.  The Linux-specific version, however, defines it only
under __USE_MISC (by conditionally including <net/ethernet.h> ... this
sure is a twisty little maze of subtly different headers, isn't it?)

inet/netinet/ether.h includes <netinet/if_ether.h> and then expects
struct ether_addr to be available.  And that's where we came in.

zw