Date: Thu, 26 Sep 2024 21:38:40 -0500
From: Nathan Bossart <nathandbossart@gmail.com>
To: Max Johnson <max.johnson@novatechautomation.com>
Cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>,
	"tgl@sss.pgh.pa.us" <tgl@sss.pgh.pa.us>
Subject: Re: pg_ctl/miscinit: print "MyStartTime" as a long long instead of
 long to avoid 2038 problem.
Message-ID: <ZvYasD2ROejOr1Fs@nathan>
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On Wed, Sep 25, 2024 at 08:04:59PM +0000, Max Johnson wrote:
> I think your patch looks good, no objections. I am happy to have contributed.

Great.  I've attached what I have staged for commit.

My first instinct was to not bother back-patching this since all
currently-supported versions will have been out of support for over 8 years
by the time this becomes a practical issue.  However, I wonder if it makes
sense to back-patch for the kinds of 32-bit embedded systems you cited
upthread.  I can imagine that such systems might need to work for a very
long time without any software updates, in which case it'd probably be a
good idea to make this fix available in the next minor release.  What do
you think?

-- 
nathan

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	filename="v4-0001-Fix-Y2K38-issues-with-MyStartTime.patch"

From 84f05c822f44b8b8ec437540bbae6bb43c72e916 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathan@postgresql.org>
Date: Thu, 26 Sep 2024 21:00:41 -0500
Subject: [PATCH v4 1/1] Fix Y2K38 issues with MyStartTime.

Several places treat MyStartTime as a "long", which is only 32 bits
wide on some platforms.  In reality, MyStartTime is a pg_time_t,
i.e., a signed 64-bit integer.  This will lead to interesting bugs
on the aforementioned systems in 2038 when signed 32-bit integers
are no longer sufficient to store Unix time (e.g., "pg_ctl start"
hanging).  To fix, ensure that MyStartTime is handled as a 64-bit
value everywhere.  (Of course, users will need to ensure that
time_t is 64 bits wide on their system, too, but there's little
that Postgres can do about that.)

This could probably be back-patched, but since all
currently-supported versions will have been out of support for over
8 years by the time this becomes a practical issue, I'm not going
to bother.

Co-authored-by: Max Johnson
Discussion: https://postgr.es/m/CO1PR07MB905262E8AC270FAAACED66008D682%40CO1PR07MB9052.namprd07.prod.outlook.com
---
 contrib/postgres_fdw/option.c                    | 3 ++-
 src/backend/utils/error/csvlog.c                 | 2 +-
 src/backend/utils/error/elog.c                   | 7 ++++---
 src/backend/utils/error/jsonlog.c                | 4 ++--
 src/backend/utils/init/miscinit.c                | 4 ++--
 src/bin/pg_ctl/pg_ctl.c                          | 2 +-
 src/include/c.h                                  | 2 ++
 src/test/modules/test_radixtree/test_radixtree.c | 2 --
 8 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/contrib/postgres_fdw/option.c b/contrib/postgres_fdw/option.c
index 630b304338..da16fc78d4 100644
--- a/contrib/postgres_fdw/option.c
+++ b/contrib/postgres_fdw/option.c
@@ -522,7 +522,8 @@ process_pgfdw_appname(const char *appname)
 				appendStringInfoString(&buf, application_name);
 				break;
 			case 'c':
-				appendStringInfo(&buf, "%lx.%x", (long) (MyStartTime), MyProcPid);
+				appendStringInfo(&buf, INT64_HEX_FORMAT ".%x",
+								 MyStartTime, MyProcPid);
 				break;
 			case 'C':
 				appendStringInfoString(&buf, cluster_name);
diff --git a/src/backend/utils/error/csvlog.c b/src/backend/utils/error/csvlog.c
index 855e130a97..acdffb6d06 100644
--- a/src/backend/utils/error/csvlog.c
+++ b/src/backend/utils/error/csvlog.c
@@ -120,7 +120,7 @@ write_csvlog(ErrorData *edata)
 	appendStringInfoChar(&buf, ',');
 
 	/* session id */
-	appendStringInfo(&buf, "%lx.%x", (long) MyStartTime, MyProcPid);
+	appendStringInfo(&buf, INT64_HEX_FORMAT ".%x", MyStartTime, MyProcPid);
 	appendStringInfoChar(&buf, ',');
 
 	/* Line number */
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 5cbb5b5416..70e4c30df3 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -2944,12 +2944,13 @@ log_status_format(StringInfo buf, const char *format, ErrorData *edata)
 				{
 					char		strfbuf[128];
 
-					snprintf(strfbuf, sizeof(strfbuf) - 1, "%lx.%x",
-							 (long) (MyStartTime), MyProcPid);
+					snprintf(strfbuf, sizeof(strfbuf) - 1, INT64_HEX_FORMAT ".%x",
+							 MyStartTime, MyProcPid);
 					appendStringInfo(buf, "%*s", padding, strfbuf);
 				}
 				else
-					appendStringInfo(buf, "%lx.%x", (long) (MyStartTime), MyProcPid);
+					appendStringInfo(buf, INT64_HEX_FORMAT ".%x",
+									 MyStartTime, MyProcPid);
 				break;
 			case 'p':
 				if (padding != 0)
diff --git a/src/backend/utils/error/jsonlog.c b/src/backend/utils/error/jsonlog.c
index bd0124869d..492383a89e 100644
--- a/src/backend/utils/error/jsonlog.c
+++ b/src/backend/utils/error/jsonlog.c
@@ -168,8 +168,8 @@ write_jsonlog(ErrorData *edata)
 	}
 
 	/* Session id */
-	appendJSONKeyValueFmt(&buf, "session_id", true, "%lx.%x",
-						  (long) MyStartTime, MyProcPid);
+	appendJSONKeyValueFmt(&buf, "session_id", true, INT64_HEX_FORMAT ".%x",
+						  MyStartTime, MyProcPid);
 
 	/* Line number */
 	appendJSONKeyValueFmt(&buf, "line_num", false, "%ld", log_line_number);
diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index 537d92c0cf..ef60f41b8c 100644
--- a/src/backend/utils/init/miscinit.c
+++ b/src/backend/utils/init/miscinit.c
@@ -1372,10 +1372,10 @@ CreateLockFile(const char *filename, bool amPostmaster,
 	 * both datadir and socket lockfiles; although more stuff may get added to
 	 * the datadir lockfile later.
 	 */
-	snprintf(buffer, sizeof(buffer), "%d\n%s\n%ld\n%d\n%s\n",
+	snprintf(buffer, sizeof(buffer), "%d\n%s\n" INT64_FORMAT "\n%d\n%s\n",
 			 amPostmaster ? (int) my_pid : -((int) my_pid),
 			 DataDir,
-			 (long) MyStartTime,
+			 MyStartTime,
 			 PostPortNumber,
 			 socketDir);
 
diff --git a/src/bin/pg_ctl/pg_ctl.c b/src/bin/pg_ctl/pg_ctl.c
index e7e878c22f..d6bb2c3311 100644
--- a/src/bin/pg_ctl/pg_ctl.c
+++ b/src/bin/pg_ctl/pg_ctl.c
@@ -618,7 +618,7 @@ wait_for_postmaster_start(pid_t pm_pid, bool do_checkpoint)
 			 * Allow 2 seconds slop for possible cross-process clock skew.
 			 */
 			pmpid = atol(optlines[LOCK_FILE_LINE_PID - 1]);
-			pmstart = atol(optlines[LOCK_FILE_LINE_START_TIME - 1]);
+			pmstart = atoll(optlines[LOCK_FILE_LINE_START_TIME - 1]);
 			if (pmstart >= start_time - 2 &&
 #ifndef WIN32
 				pmpid == pm_pid
diff --git a/src/include/c.h b/src/include/c.h
index dc1841346c..400c527397 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -547,6 +547,8 @@ typedef unsigned long long int uint64;
 /* snprintf format strings to use for 64-bit integers */
 #define INT64_FORMAT "%" INT64_MODIFIER "d"
 #define UINT64_FORMAT "%" INT64_MODIFIER "u"
+#define INT64_HEX_FORMAT "%" INT64_MODIFIER "x"
+#define UINT64_HEX_FORMAT "%" INT64_MODIFIER "x"
 
 /*
  * 128-bit signed and unsigned integers
diff --git a/src/test/modules/test_radixtree/test_radixtree.c b/src/test/modules/test_radixtree/test_radixtree.c
index 1d9165a3a2..3e6863f660 100644
--- a/src/test/modules/test_radixtree/test_radixtree.c
+++ b/src/test/modules/test_radixtree/test_radixtree.c
@@ -23,8 +23,6 @@
 /* uncomment to use shared memory for the tree */
 /* #define TEST_SHARED_RT */
 
-#define UINT64_HEX_FORMAT "%" INT64_MODIFIER "X"
-
 /* Convenient macros to test results */
 #define EXPECT_TRUE(expr)	\
 	do { \
-- 
2.39.5 (Apple Git-154)


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