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Fix crash caused by log_timezone patch if we attempt to emit any elog messages
between the setting of log_line_prefix and the setting of log_timezone. We can't realistically set log_timezone any earlier than we do now, so the best behavior seems to be to use GMT zone if any timestamps are to be logged during early startup. Create a dummy zone variable with a minimal definition of GMT (in particular it will never know about leap seconds), so that we can set it up without reference to any external files.
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5 files changed

+67
-10
lines changed

5 files changed

+67
-10
lines changed

‎src/backend/utils/error/elog.c

Lines changed: 19 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -42,7 +42,7 @@
4242
*
4343
*
4444
* IDENTIFICATION
45-
* $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.192 2007/08/04 01:26:54 tgl Exp $
45+
* $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.193 2007/08/04 19:29:25 tgl Exp $
4646
*
4747
*-------------------------------------------------------------------------
4848
*/
@@ -1497,16 +1497,25 @@ log_line_prefix(StringInfo buf)
14971497
{
14981498
struct timeval tv;
14991499
pg_time_t stamp_time;
1500+
pg_tz *tz;
15001501
char strfbuf[128],
15011502
msbuf[8];
15021503

15031504
gettimeofday(&tv, NULL);
15041505
stamp_time = (pg_time_t) tv.tv_sec;
15051506

1507+
/*
1508+
* Normally we print log timestamps in log_timezone, but
1509+
* during startup we could get here before that's set.
1510+
* If so, fall back to gmt_timezone (which guc.c ensures
1511+
* is set up before Log_line_prefix can become nonempty).
1512+
*/
1513+
tz = log_timezone ? log_timezone : gmt_timezone;
1514+
15061515
pg_strftime(strfbuf, sizeof(strfbuf),
15071516
/* leave room for milliseconds... */
15081517
"%Y-%m-%d %H:%M:%S %Z",
1509-
pg_localtime(&stamp_time, log_timezone));
1518+
pg_localtime(&stamp_time, tz));
15101519

15111520
/* 'paste' milliseconds into place... */
15121521
sprintf(msbuf, ".%03d", (int) (tv.tv_usec / 1000));
@@ -1518,22 +1527,28 @@ log_line_prefix(StringInfo buf)
15181527
case 't':
15191528
{
15201529
pg_time_t stamp_time = (pg_time_t) time(NULL);
1530+
pg_tz *tz;
15211531
char strfbuf[128];
15221532

1533+
tz = log_timezone ? log_timezone : gmt_timezone;
1534+
15231535
pg_strftime(strfbuf, sizeof(strfbuf),
15241536
"%Y-%m-%d %H:%M:%S %Z",
1525-
pg_localtime(&stamp_time, log_timezone));
1537+
pg_localtime(&stamp_time, tz));
15261538
appendStringInfoString(buf, strfbuf);
15271539
}
15281540
break;
15291541
case 's':
15301542
{
15311543
pg_time_t stamp_time = (pg_time_t) MyStartTime;
1544+
pg_tz *tz;
15321545
char strfbuf[128];
15331546

1547+
tz = log_timezone ? log_timezone : gmt_timezone;
1548+
15341549
pg_strftime(strfbuf, sizeof(strfbuf),
15351550
"%Y-%m-%d %H:%M:%S %Z",
1536-
pg_localtime(&stamp_time, log_timezone));
1551+
pg_localtime(&stamp_time, tz));
15371552
appendStringInfoString(buf, strfbuf);
15381553
}
15391554
break;

‎src/backend/utils/misc/guc.c

Lines changed: 7 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
1010
* Written by Peter Eisentraut <peter_e@gmx.net>.
1111
*
1212
* IDENTIFICATION
13-
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.409 2007/08/04 01:26:54 tgl Exp $
13+
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.410 2007/08/04 19:29:25 tgl Exp $
1414
*
1515
*--------------------------------------------------------------------
1616
*/
@@ -2926,6 +2926,12 @@ InitializeGUCOptions(void)
29262926
char *env;
29272927
long stack_rlimit;
29282928

2929+
/*
2930+
* Before log_line_prefix could possibly receive a nonempty setting,
2931+
* make sure that timezone processing is minimally alive (see elog.c).
2932+
*/
2933+
pg_timezone_pre_initialize();
2934+
29292935
/*
29302936
* Build sorted array of all GUC variables.
29312937
*/

‎src/include/pgtime.h

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
77
*
88
* IDENTIFICATION
9-
* $PostgreSQL: pgsql/src/include/pgtime.h,v 1.16 2007/08/04 01:26:54 tgl Exp $
9+
* $PostgreSQL: pgsql/src/include/pgtime.h,v 1.17 2007/08/04 19:29:25 tgl Exp $
1010
*
1111
*-------------------------------------------------------------------------
1212
*/
@@ -52,6 +52,7 @@ extern int pg_next_dst_boundary(const pg_time_t *timep,
5252
extern size_t pg_strftime(char *s, size_t max, const char *format,
5353
const struct pg_tm * tm);
5454

55+
extern void pg_timezone_pre_initialize(void);
5556
extern void pg_timezone_initialize(void);
5657
extern pg_tz *pg_tzset(const char *tzname);
5758
extern bool tz_acceptable(pg_tz *tz);
@@ -64,6 +65,7 @@ extern void pg_tzenumerate_end(pg_tzenum *dir);
6465

6566
extern pg_tz *session_timezone;
6667
extern pg_tz *log_timezone;
68+
extern pg_tz *gmt_timezone;
6769

6870
/* Maximum length of a timezone name (not including trailing null) */
6971
#define TZ_STRLEN_MAX 255

‎src/timezone/localtime.c

Lines changed: 8 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -3,7 +3,7 @@
33
* 1996-06-05 by Arthur David Olson (arthur_david_olson@nih.gov).
44
*
55
* IDENTIFICATION
6-
* $PostgreSQL: pgsql/src/timezone/localtime.c,v 1.16 2006/10/18 16:43:14 tgl Exp $
6+
* $PostgreSQL: pgsql/src/timezone/localtime.c,v 1.17 2007/08/04 19:29:25 tgl Exp $
77
*/
88

99
/*
@@ -88,7 +88,6 @@ static void timesub(const pg_time_t *timep, long offset,
8888
const struct state * sp, struct pg_tm * tmp);
8989
static pg_time_t transtime(pg_time_t janfirst, int year,
9090
const struct rule * rulep, long offset);
91-
int tzparse(const char *name, struct state * sp, int lastditch);
9291

9392
/* GMT timezone */
9493
static struct state gmtmem;
@@ -549,6 +548,12 @@ tzparse(const char *name, struct state * sp, int lastditch)
549548
if (stdlen >= sizeof sp->chars)
550549
stdlen = (sizeof sp->chars) - 1;
551550
stdoffset = 0;
551+
/*
552+
* Unlike the original zic library, do NOT invoke tzload() here;
553+
* we can't assume pg_open_tzfile() is sane yet, and we don't
554+
* care about leap seconds anyway.
555+
*/
556+
load_result = -1;
552557
}
553558
else
554559
{
@@ -561,8 +566,8 @@ tzparse(const char *name, struct state * sp, int lastditch)
561566
name = getoffset(name, &stdoffset);
562567
if (name == NULL)
563568
return -1;
569+
load_result = tzload(TZDEFRULES, NULL, sp);
564570
}
565-
load_result = tzload(TZDEFRULES, NULL, sp);
566571
if (load_result != 0)
567572
sp->leapcnt = 0; /* so, we're off a little */
568573
if (*name != '\0')

‎src/timezone/pgtz.c

Lines changed: 30 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
77
*
88
* IDENTIFICATION
9-
* $PostgreSQL: pgsql/src/timezone/pgtz.c,v 1.52 2007/08/04 01:26:54 tgl Exp $
9+
* $PostgreSQL: pgsql/src/timezone/pgtz.c,v 1.53 2007/08/04 19:29:25 tgl Exp $
1010
*
1111
*-------------------------------------------------------------------------
1212
*/
@@ -33,6 +33,10 @@ pg_tz *session_timezone = NULL;
3333
/* Current log timezone (controlled by log_timezone GUC) */
3434
pg_tz *log_timezone = NULL;
3535

36+
/* Fallback GMT timezone for last-ditch error message formatting */
37+
pg_tz *gmt_timezone = NULL;
38+
static pg_tz gmt_timezone_data;
39+
3640

3741
static char tzdir[MAXPGPATH];
3842
static bool done_tzdir = false;
@@ -1251,6 +1255,31 @@ select_default_timezone(void)
12511255
return NULL; /* keep compiler quiet */
12521256
}
12531257

1258+
1259+
/*
1260+
* Pre-initialize timezone library
1261+
*
1262+
* This is called before GUC variable initialization begins. Its purpose
1263+
* is to ensure that elog.c has a pgtz variable available to format timestamps
1264+
* with, in case log_line_prefix is set to a value requiring that. We cannot
1265+
* set log_timezone yet.
1266+
*/
1267+
void
1268+
pg_timezone_pre_initialize(void)
1269+
{
1270+
/*
1271+
* We can't use tzload() because we may not know where PGSHAREDIR
1272+
* is (in particular this is true in an EXEC_BACKEND subprocess).
1273+
* Since this timezone variable will only be used for emergency
1274+
* fallback purposes, it seems OK to just use the "lastditch" case
1275+
* provided by tzparse().
1276+
*/
1277+
if (tzparse("GMT", &gmt_timezone_data.state, TRUE) != 0)
1278+
elog(FATAL, "could not initialize GMT timezone");
1279+
strcpy(gmt_timezone_data.TZname, "GMT");
1280+
gmt_timezone = &gmt_timezone_data;
1281+
}
1282+
12541283
/*
12551284
* Initialize timezone library
12561285
*

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