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  1. Document that pg_getaddrinfo_all does not accept null hints

  1. pg_getaddrinfo_all() with hintp=NULL

    Sergey Tatarintsev <s.tatarintsev@postgrespro.ru> — 2025-11-10T05:14:57Z

    Hi!

I'm trying to use pg_getaddrinfo_all() with NULL hints, but got segfault.

According to man(3) getaddrinfo, hints may be passed as NULL. In this 
case af_family

is equivalent to AF_UNSPEC.

I'm adding a patch to pg_getaddrinfo_all() to make it available by 
passing hintp as NULL.

-- 
With best regards,
Sergey Tatarintsev,
PostgresPro

  2. Re: pg_getaddrinfo_all() with hintp=NULL

    Daniel Gustafsson <daniel@yesql.se> — 2025-11-11T16:23:16Z

    > On 10 Nov 2025, at 06:14, Sergey Tatarintsev <s.tatarintsev@postgrespro.ru> wrote:

> I'm trying to use pg_getaddrinfo_all() with NULL hints, but got segfault.
> According to man(3) getaddrinfo, hints may be passed as NULL. In this case af_family
> is equivalent to AF_UNSPEC.

Right, but pg_getaddrinfo_all isn't getaddrinfo and doesn't claim to be.  Since
pg_getaddrinfo_all can return AF_UNIX as opposed to getaddrinfo, it's not clear
why hints == NULL should mean ipv4|ipv6 here.

Accepting NULL or also (subtly) breaks the API for pg_freeaddrinfo_all which is
defined to take ai_family from the hints passed to pg_getaddrinfo_all.  Now,
reading the code makes it obvious that it will work anyways, but at the very
least a patch to accept a NULL hint should update the function comment for
pg_freeaddrinfo_all.

--
Daniel Gustafsson

  3. Re: pg_getaddrinfo_all() with hintp=NULL

    Sergey Tatarintsev <s.tatarintsev@postgrespro.ru> — 2025-11-12T08:46:33Z

    11.11.2025 23:23, Daniel Gustafsson пишет:
>> On 10 Nov 2025, at 06:14, Sergey Tatarintsev <s.tatarintsev@postgrespro.ru> wrote:
>> I'm trying to use pg_getaddrinfo_all() with NULL hints, but got segfault.
>> According to man(3) getaddrinfo, hints may be passed as NULL. In this case af_family
>> is equivalent to AF_UNSPEC.
> Right, but pg_getaddrinfo_all isn't getaddrinfo and doesn't claim to be.  Since
> pg_getaddrinfo_all can return AF_UNIX as opposed to getaddrinfo, it's not clear
> why hints == NULL should mean ipv4|ipv6 here.
>
> Accepting NULL or also (subtly) breaks the API for pg_freeaddrinfo_all which is
> defined to take ai_family from the hints passed to pg_getaddrinfo_all.  Now,
> reading the code makes it obvious that it will work anyways, but at the very
> least a patch to accept a NULL hint should update the function comment for
> pg_freeaddrinfo_all.
>
> --
> Daniel Gustafsson
>
Daniel, thanks for review!

I added a comment to pg_freeaddrinfo_all.
I don't think it made sense to comment that hint_ai_family simply 
shouldn't be equal to AF_UNIX,
so I specified that if the original hints were NULL, hint_ai_family 
should be equal to AF_UNSPEC.

-- 
With best regards,
Sergey Tatarintsev,
PostgresPro

  4. Re: pg_getaddrinfo_all() with hintp=NULL

    Daniel Gustafsson <daniel@yesql.se> — 2025-11-12T23:19:58Z

    > On 12 Nov 2025, at 09:46, Sergey Tatarintsev <s.tatarintsev@postgrespro.ru> wrote:

> I added a comment to pg_freeaddrinfo_all.
> I don't think it made sense to comment that hint_ai_family simply shouldn't be equal to AF_UNIX,
> so I specified that if the original hints were NULL, hint_ai_family should be equal to AF_UNSPEC.

Agreed.

It's still not clear to ne that we should make pg_getaddr_info() mimic the API
of getaddrinfo since it's not a thin wrapper over getaddrinfo.  The alternative
option would be to return EAI_FAIL on a null hint and force the caller to
provide an AF_UNSPEC if that is what is indeed asked for.

--
Daniel Gustafsson

  5. Re: pg_getaddrinfo_all() with hintp=NULL

    Tom Lane <tgl@sss.pgh.pa.us> — 2025-11-13T00:17:36Z

    Daniel Gustafsson <daniel@yesql.se> writes:
> It's still not clear to ne that we should make pg_getaddr_info() mimic the API
> of getaddrinfo since it's not a thin wrapper over getaddrinfo.  The alternative
> option would be to return EAI_FAIL on a null hint and force the caller to
> provide an AF_UNSPEC if that is what is indeed asked for.

We already reject null hints (by crashing), and have done for decades.
I don't think there's anything very wrong with the current code, and I
don't really see that the proposed patch is an improvement.  If
anything, I'd just add a comment to pg_getaddrinfo_all saying that
unlike bare getaddrinfo, we require a valid hintp.

			regards, tom lane

  6. Re: pg_getaddrinfo_all() with hintp=NULL

    Daniel Gustafsson <daniel@yesql.se> — 2025-11-13T13:57:52Z

    > On 13 Nov 2025, at 01:17, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Daniel Gustafsson <daniel@yesql.se> writes:

>> It's still not clear to ne that we should make pg_getaddr_info() mimic the API
>> of getaddrinfo since it's not a thin wrapper over getaddrinfo.  The alternative
>> option would be to return EAI_FAIL on a null hint and force the caller to
>> provide an AF_UNSPEC if that is what is indeed asked for.
> 
> We already reject null hints (by crashing), and have done for decades.
> I don't think there's anything very wrong with the current code, and I
> don't really see that the proposed patch is an improvement.  If
> anything, I'd just add a comment to pg_getaddrinfo_all saying that
> unlike bare getaddrinfo, we require a valid hintp.

That's my thinking as well, unless objected to I will apply the below which use
the same phrasing as the comment on pg_getnameinfo_all.

diff --git a/src/common/ip.c b/src/common/ip.c
index 0e7897a5c8f..71e5934557e 100644
--- a/src/common/ip.c
+++ b/src/common/ip.c
@@ -48,6 +48,9 @@ static int    getnameinfo_unix(const struct sockaddr_un *sa, int salen,

 /*
  *     pg_getaddrinfo_all - get address info for Unix, IPv4 and IPv6 sockets
+ *
+ * The API of this routine differs from the standard getaddrinfo() definition
+ * in that it requires a valid hintp, a null pointer is not allowed.
  */
 int
 pg_getaddrinfo_all(const char *hostname, const char *servname,

--
Daniel Gustafsson

  7. Re: pg_getaddrinfo_all() with hintp=NULL

    Tom Lane <tgl@sss.pgh.pa.us> — 2025-11-13T15:26:32Z

    Daniel Gustafsson <daniel@yesql.se> writes:
> That's my thinking as well, unless objected to I will apply the below which use
> the same phrasing as the comment on pg_getnameinfo_all.

WFM.

			regards, tom lane

  8. Re: pg_getaddrinfo_all() with hintp=NULL

    Daniel Gustafsson <daniel@yesql.se> — 2025-11-13T15:53:14Z

    > On 13 Nov 2025, at 16:26, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> 
> Daniel Gustafsson <daniel@yesql.se> writes:
>> That's my thinking as well, unless objected to I will apply the below which use
>> the same phrasing as the comment on pg_getnameinfo_all.
> 
> WFM.

Thanks, done.

--
Daniel Gustafsson