Re: getaddrinfo : Non-recoverable failure in name resolution

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Jun 23 12:15, Ken Brown wrote:
> On 6/23/2014 9:07 AM, Marco Atzeri wrote:
> >
> >On 23/06/2014 14:25, Corinna Vinschen wrote:
> >>Hi Marco,
> >>
> >>On Jun 23 13:41, Marco Atzeri wrote:
> >
> >>>
> >>>64 $ ./getaddrinfo_test-2_64
> >>>getaddrinfo: Non-recoverable failure in name resolution
> >>>
> >>>
> >>>Am I missing something ?
> >>>The second way is currently used on postgresql in several places,
> >>>but it seems to fail only for "127.0.0.1"
> >>
> >>I don't know why this only fails for "127.0.0.1".  But this is clearly a
> >>problem in the 64 bit Cygwin DLL.
> >>
> >>What happens is that the field ai_addrlen is defined as socklen_t in
> >>POSIX, but as size_t in the W32 API.  On 64 bit, socklen_t is 4 bytes
> >>while size_t is 8 bytes.  Setting all the hintp members manually (in
> >>contrast to calloc'ing it or memset'ing it to 0) leaves the 4 upper
> >>bytes of the ai_addrlen untouched.  This in turn leads to a high
> >>probability that ai_addrlen has an invalid value when entering Winsock's
> >>getsockopt.
> >>
> >>I'm really surprised this hasn't been hit before.  I'm going to fix that
> >>in Cygwin by setting the upper 4 bytes of ai_addrlen to 0 explicitely.
> >
> >Probably we have seen already but not identified.
> 
> I wonder if this could explain the mysterious emacs crashes that have been
> reported on 64-bit Cygwin.  The emacs code does set the hintp members
> manually in some places.
> 
> The crashes seem to occur randomly, and the backtraces often don't make
> sense.

A crash shouldn't occur, only getaddrinfo returning EAI_FAIL.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

Attachment: pgprAq0df2go5.pgp
Description: PGP signature