From: Tom Lane <tgl@sss.pgh.pa.us>
To: Christian Maurer <c.maurer@gmx.at>
cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18312: libpq: PQsetdbLogin() not thread-safe
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Comments: In-reply-to Christian Maurer <c.maurer@gmx.at>
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Date: Fri, 02 Feb 2024 13:19:42 -0500
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Christian Maurer <c.maurer@gmx.at> writes:
>> I wondered whether we needed to introduce a critical section
>> to prevent multiple threads from calling that concurrently,
>> even though its docs allege you shouldn't have to. Perhaps
>> it's thread-safe except on Windows?

> This would explain, why I could not reproduce the error on Red Hat Enter=
prise Linux.

Are you in a position to try a source-code patch?  The attached
is very quick-and-dirty, but if it resolves your problem then
we could turn it into something respectable.

			regards, tom lane


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diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c
index 47a28b0a3a..8906dae892 100644
--- a/src/interfaces/libpq/fe-misc.c
+++ b/src/interfaces/libpq/fe-misc.c
@@ -1243,12 +1243,17 @@ libpq_binddomain(void)
 #endif
 		const char *ldir;
 
+		pglock_thread();
+
 		/* No relocatable lookup here because the binary could be anywhere */
 		ldir = getenv("PGLOCALEDIR");
 		if (!ldir)
 			ldir = LOCALEDIR;
 		bindtextdomain(PG_TEXTDOMAIN("libpq"), ldir);
 		already_bound = true;
+
+		pgunlock_thread();
+
 #ifdef WIN32
 		SetLastError(save_errno);
 #else

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