Make uselocale protection more consistent

Started by Tristan Partinover 2 years ago7 messages
#1Tristan Partin
tristan@neon.tech
1 attachment(s)

This is a patch which implements an issue discussed in bug #17946[0]/messages/by-id/49dfcad8-90fa-8577-008f-d142e61af46b@iki.fi. It
doesn't fix the overarching issue of the bug, but merely a consistency
issue which was found while analyzing code by Heikki. I had originally
submitted the patch within that thread, but for visibility and the
purposes of the commitfest, I have re-sent it in its own thread.

[0]: /messages/by-id/49dfcad8-90fa-8577-008f-d142e61af46b@iki.fi

--
Tristan Partin
Neon (https://neon.tech)

Attachments:

v1-0001-Make-uselocale-protection-more-consistent.patchtext/x-patch; charset=utf-8; name=v1-0001-Make-uselocale-protection-more-consistent.patchDownload
From 02a2cdb83405b5aecaec2af02e379a81161f8372 Mon Sep 17 00:00:00 2001
From: Tristan Partin <tristan@neon.tech>
Date: Wed, 14 Jun 2023 11:36:00 -0500
Subject: [PATCH v1] Make uselocale protection more consistent

In ecpg, uselocale uses are protected by checking if HAVE_USELOCALE is
defined. Use the same check in pg_locale.c. Since HAVE_USELOCALE implies
HAVE_LOCALE_T, the code should be the same on _all_ platforms that
Postgres supports. Otherwise, I am sure there would have been a bug
report with pg_locale.c failing to build due to the system having
locale_t, but not uselocale.
---
 src/backend/utils/adt/pg_locale.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 31e3b16ae0..3585afb298 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -2972,7 +2972,7 @@ wchar2char(char *to, const wchar_t *from, size_t tolen, pg_locale_t locale)
 	}
 	else
 	{
-#ifdef HAVE_LOCALE_T
+#ifdef HAVE_USELOCALE
 #ifdef HAVE_WCSTOMBS_L
 		/* Use wcstombs_l for nondefault locales */
 		result = wcstombs_l(to, from, tolen, locale->info.lt);
@@ -2984,11 +2984,11 @@ wchar2char(char *to, const wchar_t *from, size_t tolen, pg_locale_t locale)
 
 		uselocale(save_locale);
 #endif							/* HAVE_WCSTOMBS_L */
-#else							/* !HAVE_LOCALE_T */
-		/* Can't have locale != 0 without HAVE_LOCALE_T */
+#else							/* !HAVE_USELOCALE */
+		/* Can't have locale != 0 without HAVE_LOCALE_T, which HAVE_USELOCALE implies */
 		elog(ERROR, "wcstombs_l is not available");
 		result = 0;				/* keep compiler quiet */
-#endif							/* HAVE_LOCALE_T */
+#endif							/* HAVE_USELOCALE */
 	}
 
 	return result;
@@ -3049,7 +3049,7 @@ char2wchar(wchar_t *to, size_t tolen, const char *from, size_t fromlen,
 		}
 		else
 		{
-#ifdef HAVE_LOCALE_T
+#ifdef HAVE_USELOCALE
 #ifdef HAVE_MBSTOWCS_L
 			/* Use mbstowcs_l for nondefault locales */
 			result = mbstowcs_l(to, str, tolen, locale->info.lt);
@@ -3061,11 +3061,11 @@ char2wchar(wchar_t *to, size_t tolen, const char *from, size_t fromlen,
 
 			uselocale(save_locale);
 #endif							/* HAVE_MBSTOWCS_L */
-#else							/* !HAVE_LOCALE_T */
-			/* Can't have locale != 0 without HAVE_LOCALE_T */
+#else							/* !HAVE_USELOCALE */
+			/* Can't have locale != 0 without HAVE_LOCALE_T, which HAVE_USELOCALE implies */
 			elog(ERROR, "mbstowcs_l is not available");
 			result = 0;			/* keep compiler quiet */
-#endif							/* HAVE_LOCALE_T */
+#endif							/* HAVE_USELOCALE */
 		}
 
 		pfree(str);
-- 
Tristan Partin
Neon (https://neon.tech)

#2Peter Eisentraut
peter@eisentraut.org
In reply to: Tristan Partin (#1)
Re: Make uselocale protection more consistent

On 27.06.23 17:02, Tristan Partin wrote:

This is a patch which implements an issue discussed in bug #17946[0]. It
doesn't fix the overarching issue of the bug, but merely a consistency
issue which was found while analyzing code by Heikki. I had originally
submitted the patch within that thread, but for visibility and the
purposes of the commitfest, I have re-sent it in its own thread.

[0]: /messages/by-id/49dfcad8-90fa-8577-008f-d142e61af46b@iki.fi

I notice that HAVE_USELOCALE was introduced much later than
HAVE_LOCALE_T, and at the time the code was already using uselocale(),
so perhaps the introduction of HAVE_USELOCALE was unnecessary and should
be reverted.

I think it would be better to keep HAVE_LOCALE_T as encompassing any of
the various locale_t-using functions, rather than using HAVE_USELOCALE
as a proxy for them. Otherwise you create weird situations like having
#ifdef HAVE_WCSTOMBS_L inside #ifdef HAVE_USELOCALE, which doesn't make
sense, I think.

#3Thomas Munro
thomas.munro@gmail.com
In reply to: Peter Eisentraut (#2)
Re: Make uselocale protection more consistent

On Mon, Jul 3, 2023 at 6:13 PM Peter Eisentraut <peter@eisentraut.org> wrote:

On 27.06.23 17:02, Tristan Partin wrote:

This is a patch which implements an issue discussed in bug #17946[0]. It
doesn't fix the overarching issue of the bug, but merely a consistency
issue which was found while analyzing code by Heikki. I had originally
submitted the patch within that thread, but for visibility and the
purposes of the commitfest, I have re-sent it in its own thread.

[0]: /messages/by-id/49dfcad8-90fa-8577-008f-d142e61af46b@iki.fi

I notice that HAVE_USELOCALE was introduced much later than
HAVE_LOCALE_T, and at the time the code was already using uselocale(),
so perhaps the introduction of HAVE_USELOCALE was unnecessary and should
be reverted.

I think it would be better to keep HAVE_LOCALE_T as encompassing any of
the various locale_t-using functions, rather than using HAVE_USELOCALE
as a proxy for them. Otherwise you create weird situations like having
#ifdef HAVE_WCSTOMBS_L inside #ifdef HAVE_USELOCALE, which doesn't make
sense, I think.

I propose[1]/messages/by-id/CA+hUKGL7CmmzeRhoirzjECmOdABVFTn8fo6gEOaFRF1Oxey6Hw@mail.gmail.com that we get rid of HAVE_LOCALE_T completely and make
"libc" provider support unconditional. It's standardised, and every
target system has it, even Windows. But Windows doesn't have
uselocale().

[1]: /messages/by-id/CA+hUKGL7CmmzeRhoirzjECmOdABVFTn8fo6gEOaFRF1Oxey6Hw@mail.gmail.com

#4Tristan Partin
tristan@neon.tech
In reply to: Thomas Munro (#3)
Re: Make uselocale protection more consistent

On Mon Jul 3, 2023 at 1:24 AM CDT, Thomas Munro wrote:

On Mon, Jul 3, 2023 at 6:13 PM Peter Eisentraut <peter@eisentraut.org> wrote:

On 27.06.23 17:02, Tristan Partin wrote:

This is a patch which implements an issue discussed in bug #17946[0]. It
doesn't fix the overarching issue of the bug, but merely a consistency
issue which was found while analyzing code by Heikki. I had originally
submitted the patch within that thread, but for visibility and the
purposes of the commitfest, I have re-sent it in its own thread.

[0]: /messages/by-id/49dfcad8-90fa-8577-008f-d142e61af46b@iki.fi

I notice that HAVE_USELOCALE was introduced much later than
HAVE_LOCALE_T, and at the time the code was already using uselocale(),
so perhaps the introduction of HAVE_USELOCALE was unnecessary and should
be reverted.

I think it would be better to keep HAVE_LOCALE_T as encompassing any of
the various locale_t-using functions, rather than using HAVE_USELOCALE
as a proxy for them. Otherwise you create weird situations like having
#ifdef HAVE_WCSTOMBS_L inside #ifdef HAVE_USELOCALE, which doesn't make
sense, I think.

I propose[1] that we get rid of HAVE_LOCALE_T completely and make
"libc" provider support unconditional. It's standardised, and every
target system has it, even Windows. But Windows doesn't have
uselocale().

[1] /messages/by-id/CA+hUKGL7CmmzeRhoirzjECmOdABVFTn8fo6gEOaFRF1Oxey6Hw@mail.gmail.com

I think keeping HAVE_USELOCALE is important for the Windows case as
mentioned. I need it for my localization work where I am ripping out
setlocale() on non-Windows.

--
Tristan Partin
Neon (https://neon.tech)

#5Peter Eisentraut
peter@eisentraut.org
In reply to: Thomas Munro (#3)
Re: Make uselocale protection more consistent

On 03.07.23 08:24, Thomas Munro wrote:

I propose[1] that we get rid of HAVE_LOCALE_T completely and make
"libc" provider support unconditional. It's standardised, and every
target system has it, even Windows. But Windows doesn't have
uselocale().

[1] /messages/by-id/CA+hUKGL7CmmzeRhoirzjECmOdABVFTn8fo6gEOaFRF1Oxey6Hw@mail.gmail.com

Ok, it appears your patch is imminent, so let's wait for that and see if
this patch here is still required afterwards.

#6Peter Eisentraut
peter@eisentraut.org
In reply to: Tristan Partin (#4)
Re: Make uselocale protection more consistent

On 03.07.23 15:21, Tristan Partin wrote:

I think it would be better to keep HAVE_LOCALE_T as encompassing any of
the various locale_t-using functions, rather than using HAVE_USELOCALE
as a proxy for them. Otherwise you create weird situations like having
#ifdef HAVE_WCSTOMBS_L inside #ifdef HAVE_USELOCALE, which doesn't make
sense, I think.

I propose[1] that we get rid of HAVE_LOCALE_T completely and make
"libc" provider support unconditional. It's standardised, and every
target system has it, even Windows. But Windows doesn't have
uselocale().

[1]/messages/by-id/CA+hUKGL7CmmzeRhoirzjECmOdABVFTn8fo6gEOaFRF1Oxey6Hw@mail.gmail.com

I think keeping HAVE_USELOCALE is important for the Windows case as
mentioned. I need it for my localization work where I am ripping out
setlocale() on non-Windows.

The current code is structured

#ifdef HAVE_LOCALE_T
#ifdef HAVE_WCSTOMBS_L
wcstombs_l(...);
#else
uselocale(...);
#endif
#else
elog(ERROR);
#endif

If you just replace HAVE_LOCALE_T with HAVE_USELOCALE, then this would
penalize a platform that has wcstombs_l(), but not uselocale(). I think
the correct structure would be

#if defined(HAVE_WCSTOMBS_L)
wcstombs_l(...);
#elif defined(HAVE_USELOCALE)
uselocale(...);
#else
elog(ERROR);
#endif

#7Tristan Partin
tristan@neon.tech
In reply to: Peter Eisentraut (#6)
Re: Make uselocale protection more consistent

On Mon Jul 3, 2023 at 9:21 AM CDT, Peter Eisentraut wrote:

On 03.07.23 15:21, Tristan Partin wrote:

I think it would be better to keep HAVE_LOCALE_T as encompassing any of
the various locale_t-using functions, rather than using HAVE_USELOCALE
as a proxy for them. Otherwise you create weird situations like having
#ifdef HAVE_WCSTOMBS_L inside #ifdef HAVE_USELOCALE, which doesn't make
sense, I think.

I propose[1] that we get rid of HAVE_LOCALE_T completely and make
"libc" provider support unconditional. It's standardised, and every
target system has it, even Windows. But Windows doesn't have
uselocale().

[1]/messages/by-id/CA+hUKGL7CmmzeRhoirzjECmOdABVFTn8fo6gEOaFRF1Oxey6Hw@mail.gmail.com

I think keeping HAVE_USELOCALE is important for the Windows case as
mentioned. I need it for my localization work where I am ripping out
setlocale() on non-Windows.

The current code is structured

#ifdef HAVE_LOCALE_T
#ifdef HAVE_WCSTOMBS_L
wcstombs_l(...);
#else
uselocale(...);
#endif
#else
elog(ERROR);
#endif

If you just replace HAVE_LOCALE_T with HAVE_USELOCALE, then this would
penalize a platform that has wcstombs_l(), but not uselocale(). I think
the correct structure would be

#if defined(HAVE_WCSTOMBS_L)
wcstombs_l(...);
#elif defined(HAVE_USELOCALE)
uselocale(...);
#else
elog(ERROR);
#endif

That makes sense to me. I gave it some more thought. Maybe it makes more
sense to just completely drop HAVE_USELOCALE as mentioned, and protect
calls to it with #ifdef WIN32 or whatever the macro is. HAVE_USELOCALE
might be more descriptive, but I don't really care that much either way.

--
Tristan Partin
Neon (https://neon.tech)