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Re: getaddrinfo : Non-recoverable failure in name resolution



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.

For the time being, you might prepend

   memset (&hintp, 0, sizeof hintp);

to the code, prior to setting the elements manually.

I will wait next snapshot.
PostgreSQL 9.4 is still on Beta 1, so I am not in a hurry to release
a new version


Thanks for the testcase.  Much appreciated,
Corinna

Thanks for the solution
Marco

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