From 0c7c94f90cd4ee005fac84f30cb7ee5e0c96a835 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 21 Jan 2022 15:36:12 -0500
Subject: [PATCH] Fix race condition in gettext() initialization in libpq and
ecpglib.
In libpq and ecpglib, multiple threads can concurrently enter the
initialization logic for message localization. Since we set the
its-done flag before actually doing the work, it'd be possible
for some threads to reach gettext() before anyone has called
bindtextdomain(). Barring bugs in libintl itself, this would not
result in anything worse than failure to localize some early
messages. Nonetheless, it's a bug, and an easy one to fix.
Noted while investigating bug #17299 from Clemens Zeidler
(much thanks to Liam Bowen for followup investigation on that).
It currently appears that that actually *is* a bug in libintl itself,
but that doesn't let us off the hook for this bit.
Back-patch to all supported versions.
Discussion: https://postgr.es/m/17299-7270741958c0b1ab@postgresql.org
Discussion: https://postgr.es/m/CAE7q7Eit4Eq2=bxce=Fm8HAStECjaXUE=WBQc-sDDcgJQ7s7eg@mail.gmail.com
---
src/interfaces/ecpg/ecpglib/misc.c | 11 +++++++++--
src/interfaces/libpq/fe-misc.c | 11 +++++++++--
2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/src/interfaces/ecpg/ecpglib/misc.c b/src/interfaces/ecpg/ecpglib/misc.c
index 25094e43969..1ccf73f0bbd 100644
--- a/src/interfaces/ecpg/ecpglib/misc.c
+++ b/src/interfaces/ecpg/ecpglib/misc.c
@@ -489,7 +489,14 @@ win32_pthread_once(volatile pthread_once_t *once, void (*fn) (void))
char *
ecpg_gettext(const char *msgid)
{
- static bool already_bound = false;
+ /*
+ * If multiple threads come through here at about the same time, it's okay
+ * for more than one of them to call bindtextdomain(). But it's not okay
+ * for any of them to reach dgettext() before bindtextdomain() is
+ * complete, so don't set the flag till that's done. Use "volatile" just
+ * to be sure the compiler doesn't try to get cute.
+ */
+ static volatile bool already_bound = false;
if (!already_bound)
{
@@ -501,12 +508,12 @@ ecpg_gettext(const char *msgid)
#endif
const char *ldir;
- already_bound = true;
/* No relocatable lookup here because the binary could be anywhere */
ldir = getenv("PGLOCALEDIR");
if (!ldir)
ldir = LOCALEDIR;
bindtextdomain(PG_TEXTDOMAIN("ecpglib"), ldir);
+ already_bound = true;
#ifdef WIN32
SetLastError(save_errno);
#else
diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c
index 864e8853aeb..6391a4109bf 100644
--- a/src/interfaces/libpq/fe-misc.c
+++ b/src/interfaces/libpq/fe-misc.c
@@ -1219,7 +1219,14 @@ PQenv2encoding(void)
static void
libpq_binddomain()
{
- static bool already_bound = false;
+ /*
+ * If multiple threads come through here at about the same time, it's okay
+ * for more than one of them to call bindtextdomain(). But it's not okay
+ * for any of them to return to caller before bindtextdomain() is
+ * complete, so don't set the flag till that's done. Use "volatile" just
+ * to be sure the compiler doesn't try to get cute.
+ */
+ static volatile bool already_bound = false;
if (!already_bound)
{
@@ -1231,12 +1238,12 @@ libpq_binddomain()
#endif
const char *ldir;
- already_bound = true;
/* 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;
#ifdef WIN32
SetLastError(save_errno);
#else
--
2.39.5