Re: [PATCH] ident.c: add support for IPv6

["Torsten Bögershausen" <tboegi@web.de>]

On 2015-10-30 15.48, Elia Pinto wrote:
> Add IPv6 support by implementing name resolution with the
Minor question: How is this related to IPV6?
Could the header line be written something like

"ident.c: Use getaddrinfo() instead of gethostbyname() if available"

On which systems has the patch been tested ?
Linux ?
Mac OS X ?
Windows ?
BSD ?

The motivation on which platforms the usage of getaddrinfo() is preferred
over gethostbyname() could be helpful to motivate this patch:
System XYZ behaves bad when gethostbyname() is used.
Fix it by using getaddrinfo() instead.

A more defensive patch could call getaddrinfo() (If available, iow
when NO_IPV6 is false), and if that fails for whatever reason,
fall back to gethostbyname(), which should be available on all systems.


> protocol agnostic getaddrinfo(3) API. The old gethostbyname(3)
> code is still available when git is compiled with NO_IPV6.
> 
> Signed-off-by: Elia Pinto <gitter.spiros@gmail.com>
> ---
>  ident.c | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/ident.c b/ident.c
> index 5ff1aad..86b62be 100644
> --- a/ident.c
> +++ b/ident.c
> @@ -69,6 +69,34 @@ static int add_mailname_host(struct strbuf *buf)
>  	fclose(mailname);
>  	return 0;
>  }
> +#ifndef NO_IPV6
> +
> +static void add_domainname(struct strbuf *out)
> +{
> +	char buf[1024];
> +	struct addrinfo hints, *ai;
> +	int gai;
The scope of these variables can be narrowed, by moving them into the "{" block,
where they are needed. (Before the memset())
> +
> +	if (gethostname(buf, sizeof(buf))) {
> +		warning("cannot get host name: %s", strerror(errno));
> +		strbuf_addstr(out, "(none)");
> +		return;
> +	}
> +	if (strchr(buf, '.'))
> +		strbuf_addstr(out, buf);
> +	else	{
Many ' ' between else and '{', one should be enough
> +		memset (&hints, '\0', sizeof (hints));
> +		hints.ai_flags = AI_CANONNAME;
> +		if (!(gai = getaddrinfo(buf, NULL, &hints, &ai)) && ai && strchr(ai->ai_canonname, '.')) {
> +			strbuf_addstr(out, ai->ai_canonname);
> +			freeaddrinfo(ai);
> +		}
> +		else
Colud be written in one line as "} else"
> +			strbuf_addf(out, "%s.(none)", buf);
> +	}
> +}
> +#else /* NO_IPV6 */