Aw: Re: Re: Homebrew and Git

> Gesendet: Mittwoch, 21. September 2016 um 10:48 Uhr
> Von: "Jeff King" <peff@peff.net>
> An: "John Keeping" <john@keeping.me.uk>
> Cc: "Heiko Voigt" <hvoigt@hvoigt.net>, "Jonas Thiel" <jonas.lierschied@gmx.de>, git@vger.kernel.org
> Betreff: Re: Re: Homebrew and Git
>
> On Tue, Sep 20, 2016 at 08:15:55PM +0100, John Keeping wrote:
> 
> > > BTW, here is the callstack inlined from the crashreport:
> > > 
> > > bsystem_platform.dylib      	0x00007fff840db41c _platform_strchr$VARIANT$Haswell + 28
> > > 1   git                           	0x000000010ba1d3f4 ident_default_email + 801
> > > 2   git                           	0x000000010ba1d68f fmt_ident + 66
> > > 3   git                           	0x000000010ba4b495 files_log_ref_write + 175
> > > 4   git                           	0x000000010ba4b0a6 commit_ref_update + 106
> > > 5   git                           	0x000000010ba4c3a8 ref_transaction_commit + 468
> > > 6   git                           	0x000000010b994dd8 s_update_ref + 271
> > > 7   git                           	0x000000010b994556 fetch_refs + 1969
> > > 8   git                           	0x000000010b9935f2 fetch_one + 1913
> > > 9   git                           	0x000000010b992bc4 cmd_fetch + 549
> > > 10  git                           	0x000000010b9666c4 handle_builtin + 478
> > > 11  git                           	0x000000010b96602f main + 376
> > > 12  libdyld.dylib                 	0x00007fff834ef5ad start + 1
> > > 
> > > Maybe someone else has an idea what might be causing this...
> > 
> > The only strchr I can see that could be called here is in
> > canonical_name(), where it's called with addrinfo::ai_canonname.
> 
> There's one in add_domainname(), too, but it can never be NULL (we could
> walk off the end of the buffer, but only if gethostname() lies to us
> about its result code, which seems unlikely). So I agree it's probably
> the call in canonical_name().
> 
> > Searching for OS X and ai_canonname, leads me straight back to this
> > list, although 7 years ago!  I think ident.c needs a fix similar to
> > commit 3e8a00a (daemon.c: fix segfault on OS X, 2009-04-27); from the
> > commit message there:
> > 
> > 	On OS X (and maybe other unices), getaddrinfo(3) returns NULL
> > 	in the ai_canonname field if it's called with an IP address for
> > 	the hostname.
> 
> Interesting. We are already prepared for failure from getaddrinfo()
> here, so probably:
> 
> diff --git a/ident.c b/ident.c
> index e20a772..d17b5bd 100644
> --- a/ident.c
> +++ b/ident.c
> @@ -101,7 +101,7 @@ static int canonical_name(const char *host, struct strbuf *out)
>  	memset (&hints, '\0', sizeof (hints));
>  	hints.ai_flags = AI_CANONNAME;
>  	if (!getaddrinfo(host, NULL, &hints, &ai)) {
> -		if (ai && strchr(ai->ai_canonname, '.')) {
> +		if (ai && ai->ai_canonname && strchr(ai->ai_canonname, '.')) {
>  			strbuf_addstr(out, ai->ai_canonname);
>  			status = 0;
>  		}
> 
> would be sufficient. Jonas, can you see if that patch helps?
> 
> -Peff
>