On Wed, Jun 10, 2015 at 10:09:38AM -0400, Tom Lane wrote:
> Noah Misch <n...@leadboat.com> writes:
> > I can reproduce this with "initdb --locale=C",
> > postgresql-9.4.3-1-windows-binaries.zip (32-bit), Windows 7 x64, and the
> > Windows ANSI code page set to CP936. (Choose "Chinese (Simplified, PRC)" in
> > Control Panel -> Region and Language -> Administrative -> Language for
> > non-Unicode programs.) It is neither necessary nor sufficient to change
> > Control Panel -> Region and Language -> Formats -> Format. Binaries from
> > postgresql-9.4.3-1-windows-x64-binaries.zip do not exhibit the problem.
> > Note
> > that CP936 is a PG_ENCODING_IS_CLIENT_ONLY() encoding.
>
> Hm. I could understand getting encoding difficulties in that environment,
> but it's hard to see why they'd manifest like this. Can you trace through
> pg_perm_setlocale and figure out why it's reporting failure?
A faster test is to set LC_CTYPE=C in the environment and run "postgres
--version". The root cause is a bug my commit 5f538ad introduced at the start
of the 9.4 cycle. pg_perm_setlocale() now calls pg_bind_textdomain_codeset(),
which calls setlocale(LC_CTYPE, NULL). POSIX permits that to clobber all
previous setlocale() return values, which it did here[1]. The ensuing
putenv("LC_CTYPE=<garbage bytes>") at the end of pg_perm_setlocale() fails
under Windows ANSI code page 936, because the garbage bytes often aren't a
valid CP936 string. I would expect the same symptom on other multibyte
Windows locales.
While Windows was the bellwether, harm potential is greater on non-Windows
systems. pg_perm_setlocale() sets the LC_CTYPE environment variable to help
PL/Perl avoid clobbering the process locale; see plperl_init_interp()
comments. However, that function has bespoke code for Windows, on which
setting the environment variable doesn't help. I don't know which other
platforms invalidate previous setlocale() return values on setlocale(LC_CTYPE,
NULL). Therefore, I propose committing the attached diagnostic patch and
reverting it after about one buildfarm cycle. It will make affected
configurations fail hard, and then I'll have a notion about the prevalence of
damage to expect in the field.
The actual fix is trivial, attached second. This is for back-patch to 9.4.
[1] It does so in 32-bit "release" (non-debug), NLS builds done under Visual
Studio 2012 and Visual Studio 2013. The official binaries used VS2013. The
symptoms are slightly different under VS2012. I did not test earlier
versions. Debug builds and 64-bit builds were unaffected.
diff --git a/src/backend/utils/adt/pg_locale.c
b/src/backend/utils/adt/pg_locale.c
index 4be735e..d33081b 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -58,6 +58,7 @@
#include "catalog/pg_collation.h"
#include "catalog/pg_control.h"
#include "mb/pg_wchar.h"
+#include "utils/builtins.h"
#include "utils/hsearch.h"
#include "utils/memutils.h"
#include "utils/pg_locale.h"
@@ -148,6 +149,7 @@ pg_perm_setlocale(int category, const char *locale)
char *result;
const char *envvar;
char *envbuf;
+ char orig_result[LC_ENV_BUFSIZE];
#ifndef WIN32
result = setlocale(category, locale);
@@ -173,6 +175,7 @@ pg_perm_setlocale(int category, const char *locale)
if (result == NULL)
return result; /* fall out immediately on
failure */
+ strlcpy(orig_result, result, sizeof(orig_result));
/*
* Use the right encoding in translated messages. Under ENABLE_NLS, let
@@ -231,6 +234,15 @@ pg_perm_setlocale(int category, const char *locale)
}
snprintf(envbuf, LC_ENV_BUFSIZE - 1, "%s=%s", envvar, result);
+ if (strcmp(orig_result, result) != 0)
+ {
+ char hex[2 * LC_ENV_BUFSIZE + 1];
+
+ hex_encode(result, Min(1 + strlen(result), LC_ENV_BUFSIZE),
hex);
+ hex[sizeof(hex) - 1] = '\0';
+ elog(FATAL, "setlocale() result %s clobbered to 0x%s",
+ orig_result, hex);
+ }
if (putenv(envbuf))
return NULL;
diff --git a/src/backend/utils/adt/pg_locale.c
b/src/backend/utils/adt/pg_locale.c
index 4be735e..84215e0 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -183,6 +183,12 @@ pg_perm_setlocale(int category, const char *locale)
*/
if (category == LC_CTYPE)
{
+ static char save_lc_ctype[LC_ENV_BUFSIZE];
+
+ /* copy setlocale() return value before callee invokes it again
*/
+ strlcpy(save_lc_ctype, result, sizeof(save_lc_ctype));
+ result = save_lc_ctype;
+
#ifdef ENABLE_NLS
SetMessageEncoding(pg_bind_textdomain_codeset(textdomain(NULL)));
#else
--
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