pageinspect: Change block number arguments to bigint

Block numbers are 32-bit unsigned integers.  Therefore, the smallest
SQL integer type that they can fit in is bigint.  However, in the
pageinspect module, most input and output parameters dealing with
block numbers were declared as int.  The behavior with block numbers
larger than a signed 32-bit integer was therefore dubious.  Change
these arguments to type bigint and add some more explicit error
checking on the block range.

(Other contrib modules appear to do this correctly already.)

Since we are changing argument types of existing functions, in order
to not misbehave if the binary is updated before the extension is
updated, we need to create new C symbols for the entry points, similar
to how it's done in other extensions as well.

Reported-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://www.postgresql.org/message-id/flat/d8f6bdd536df403b9b33816e9f7e0b9d@G08CNEXMBPEKD05.g08.fujitsu.local

1 files changed, 72 insertions, 3 deletions

diff --git a/contrib/pageinspect/rawpage.c b/contrib/pageinspect/rawpage.c
index ae1dc41e055..9e9ee8a493f 100644
--- a/contrib/pageinspect/rawpage.c
+++ b/contrib/pageinspect/rawpage.c
@@ -40,6 +40,28 @@ static bytea *get_raw_page_internal(text *relname, ForkNumber forknum,
  *
  * Returns a copy of a page from shared buffers as a bytea
  */
+PG_FUNCTION_INFO_V1(get_raw_page_1_9);
+
+Datum
+get_raw_page_1_9(PG_FUNCTION_ARGS)
+{
+	text	   *relname = PG_GETARG_TEXT_PP(0);
+	int64		blkno = PG_GETARG_INT64(1);
+	bytea	   *raw_page;
+
+	if (blkno < 0 || blkno > MaxBlockNumber)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("invalid block number")));
+
+	raw_page = get_raw_page_internal(relname, MAIN_FORKNUM, blkno);
+
+	PG_RETURN_BYTEA_P(raw_page);
+}
+
+/*
+ * entry point for old extension version
+ */
 PG_FUNCTION_INFO_V1(get_raw_page);
 
 Datum
@@ -69,6 +91,32 @@ get_raw_page(PG_FUNCTION_ARGS)
  *
  * Same, for any fork
  */
+PG_FUNCTION_INFO_V1(get_raw_page_fork_1_9);
+
+Datum
+get_raw_page_fork_1_9(PG_FUNCTION_ARGS)
+{
+	text	   *relname = PG_GETARG_TEXT_PP(0);
+	text	   *forkname = PG_GETARG_TEXT_PP(1);
+	int64		blkno = PG_GETARG_INT64(2);
+	bytea	   *raw_page;
+	ForkNumber	forknum;
+
+	forknum = forkname_to_number(text_to_cstring(forkname));
+
+	if (blkno < 0 || blkno > MaxBlockNumber)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("invalid block number")));
+
+	raw_page = get_raw_page_internal(relname, forknum, blkno);
+
+	PG_RETURN_BYTEA_P(raw_page);
+}
+
+/*
+ * Entry point for old extension version
+ */
 PG_FUNCTION_INFO_V1(get_raw_page_fork);
 
 Datum
@@ -292,13 +340,14 @@ page_header(PG_FUNCTION_ARGS)
  * Compute checksum of a raw page
  */
 
+PG_FUNCTION_INFO_V1(page_checksum_1_9);
 PG_FUNCTION_INFO_V1(page_checksum);
 
-Datum
-page_checksum(PG_FUNCTION_ARGS)
+static Datum
+page_checksum_internal(PG_FUNCTION_ARGS, enum pageinspect_version ext_version)
 {
 	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
-	uint32		blkno = PG_GETARG_INT32(1);
+	int64		blkno = (ext_version == PAGEINSPECT_V1_8 ? PG_GETARG_UINT32(1) : PG_GETARG_INT64(1));
 	int			raw_page_size;
 	PageHeader	page;
 
@@ -307,6 +356,11 @@ page_checksum(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 errmsg("must be superuser to use raw page functions")));
 
+	if (blkno < 0 || blkno > MaxBlockNumber)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("invalid block number")));
+
 	raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
 
 	/*
@@ -321,3 +375,18 @@ page_checksum(PG_FUNCTION_ARGS)
 
 	PG_RETURN_INT16(pg_checksum_page((char *) page, blkno));
 }
+
+Datum
+page_checksum_1_9(PG_FUNCTION_ARGS)
+{
+	return page_checksum_internal(fcinfo, PAGEINSPECT_V1_9);
+}
+
+/*
+ * Entry point for old extension version
+ */
+Datum
+page_checksum(PG_FUNCTION_ARGS)
+{
+	return page_checksum_internal(fcinfo, PAGEINSPECT_V1_8);
+}