Hi all,
Attached is a patch that resolves an overflow in pg_size_pretty() that
resulted in unexpected behavior when PG_INT64_MIN was passed in as an
argument.
The pg_abs_s64() helper function is extracted and simplified from patch
0001 from [0]. I didn't add similar functions for other sized integers
since they'd be unused, but I'd be happy to add them if others
disagree.
`SELECT -9223372036854775808::bigint` results in an out of range error,
even though `-9223372036854775808` can fit in a `bigint` and
`SELECT pg_typeof(-9223372036854775808)` returns `bigint`. That's why
the `::bigint` cast is omitted from my test.
[0]
https://www.postgresql.org/message-id/flat/caavxfhdbpoyegs7s+xf4iaw0-cgiq25jpydwbqqqvltle_t...@mail.gmail.com
Thanks,
Joseph Koshakow
From 6ec885412f2e0f3a3e019ec1906901e39c6d517a Mon Sep 17 00:00:00 2001
From: Joseph Koshakow <kosh...@gmail.com>
Date: Sat, 27 Jul 2024 15:06:09 -0400
Subject: [PATCH] Fix overflow in pg_size_pretty
This commit removes an overflow from pg_size_pretty that causes
PG_INT64_MIN to by displayed with the bytes unit instead of the PB
unit.
---
src/backend/utils/adt/dbsize.c | 3 ++-
src/include/common/int.h | 13 +++++++++++++
src/test/regress/expected/dbsize.out | 6 ++++++
src/test/regress/sql/dbsize.sql | 2 ++
4 files changed, 23 insertions(+), 1 deletion(-)
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index 25d7110c13..5648f40101 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -21,6 +21,7 @@
#include "catalog/pg_tablespace.h"
#include "commands/dbcommands.h"
#include "commands/tablespace.h"
+#include "common/int.h"
#include "miscadmin.h"
#include "storage/fd.h"
#include "utils/acl.h"
@@ -577,7 +578,7 @@ pg_size_pretty(PG_FUNCTION_ARGS)
uint8 bits;
/* use this unit if there are no more units or we're below the limit */
- if (unit[1].name == NULL || i64abs(size) < unit->limit)
+ if (unit[1].name == NULL || pg_abs_s64(size) < unit->limit)
{
if (unit->round)
size = half_rounded(size);
diff --git a/src/include/common/int.h b/src/include/common/int.h
index 7fc046e78a..d86eb6dd5e 100644
--- a/src/include/common/int.h
+++ b/src/include/common/int.h
@@ -258,6 +258,19 @@ pg_mul_s64_overflow(int64 a, int64 b, int64 *result)
#endif
}
+static inline uint64
+pg_abs_s64(int64 a)
+{
+ if (unlikely(a == PG_INT64_MIN))
+ {
+ return ((uint64) PG_INT64_MAX) + 1;
+ }
+ else
+ {
+ return (uint64) i64abs(a);
+ }
+}
+
/*------------------------------------------------------------------------
* Overflow routines for unsigned integers
*------------------------------------------------------------------------
diff --git a/src/test/regress/expected/dbsize.out b/src/test/regress/expected/dbsize.out
index f1121a87aa..3398a3eceb 100644
--- a/src/test/regress/expected/dbsize.out
+++ b/src/test/regress/expected/dbsize.out
@@ -12,6 +12,12 @@ SELECT size, pg_size_pretty(size), pg_size_pretty(-1 * size) FROM
1000000000000000 | 909 TB | -909 TB
(6 rows)
+SELECT pg_size_pretty(-9223372036854775808);
+ pg_size_pretty
+----------------
+ -8192 PB
+(1 row)
+
SELECT size, pg_size_pretty(size), pg_size_pretty(-1 * size) FROM
(VALUES (10::numeric), (1000::numeric), (1000000::numeric),
(1000000000::numeric), (1000000000000::numeric),
diff --git a/src/test/regress/sql/dbsize.sql b/src/test/regress/sql/dbsize.sql
index b34cf33385..e3e18e948e 100644
--- a/src/test/regress/sql/dbsize.sql
+++ b/src/test/regress/sql/dbsize.sql
@@ -3,6 +3,8 @@ SELECT size, pg_size_pretty(size), pg_size_pretty(-1 * size) FROM
(1000000000::bigint), (1000000000000::bigint),
(1000000000000000::bigint)) x(size);
+SELECT pg_size_pretty(-9223372036854775808);
+
SELECT size, pg_size_pretty(size), pg_size_pretty(-1 * size) FROM
(VALUES (10::numeric), (1000::numeric), (1000000::numeric),
(1000000000::numeric), (1000000000000::numeric),
--
2.34.1
