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

contrib/pageinspect/expected/btree.out

@@ -14,6 +14,8 @@ oldest_xact             | 0
 last_cleanup_num_tuples | -1
 allequalimage           | t
 
+SELECT * FROM bt_page_stats('test1_a_idx', -1);
+ERROR:  invalid block number
 SELECT * FROM bt_page_stats('test1_a_idx', 0);
 ERROR:  block 0 is a meta page
 SELECT * FROM bt_page_stats('test1_a_idx', 1);
@@ -32,6 +34,8 @@ btpo_flags    | 3
 
 SELECT * FROM bt_page_stats('test1_a_idx', 2);
 ERROR:  block number out of range
+SELECT * FROM bt_page_items('test1_a_idx', -1);
+ERROR:  invalid block number
 SELECT * FROM bt_page_items('test1_a_idx', 0);
 ERROR:  block 0 is a meta page
 SELECT * FROM bt_page_items('test1_a_idx', 1);
@@ -48,6 +52,8 @@ tids       |
 
 SELECT * FROM bt_page_items('test1_a_idx', 2);
 ERROR:  block number out of range
+SELECT * FROM bt_page_items(get_raw_page('test1_a_idx', -1));
+ERROR:  invalid block number
 SELECT * FROM bt_page_items(get_raw_page('test1_a_idx', 0));
 ERROR:  block is a meta page
 SELECT * FROM bt_page_items(get_raw_page('test1_a_idx', 1));

contrib/pageinspect/expected/gin.out

@@ -35,3 +35,4 @@ FROM gin_leafpage_items(get_raw_page('test1_y_idx',
 -[ RECORD 1 ]
 ?column? | t
 
+DROP TABLE test1;

contrib/pageinspect/expected/hash.out

@@ -28,6 +28,8 @@ hash_page_type | bitmap
 
 SELECT hash_page_type(get_raw_page('test_hash_a_idx', 6));
 ERROR:  block number 6 is out of range for relation "test_hash_a_idx"
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', -1);
+ERROR:  invalid block number
 SELECT * FROM hash_bitmap_info('test_hash_a_idx', 0);
 ERROR:  invalid overflow block number 0
 SELECT * FROM hash_bitmap_info('test_hash_a_idx', 1);
@@ -40,6 +42,8 @@ SELECT * FROM hash_bitmap_info('test_hash_a_idx', 4);
 ERROR:  invalid overflow block number 4
 SELECT * FROM hash_bitmap_info('test_hash_a_idx', 5);
 ERROR:  invalid overflow block number 5
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 6);
+ERROR:  block number 6 is out of range for relation "test_hash_a_idx"
 SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
 lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
 hash_metapage_info(get_raw_page('test_hash_a_idx', 0));

contrib/pageinspect/expected/oldextversions.out

@@ -0,0 +1,40 @@
+-- test old extension version entry points
+DROP EXTENSION pageinspect;
+CREATE EXTENSION pageinspect VERSION '1.8';
+CREATE TABLE test1 (a int8, b text);
+INSERT INTO test1 VALUES (72057594037927937, 'text');
+CREATE INDEX test1_a_idx ON test1 USING btree (a);
+-- from page.sql
+SELECT octet_length(get_raw_page('test1', 0)) AS main_0;
+ main_0 
+--------
+   8192
+(1 row)
+
+SELECT octet_length(get_raw_page('test1', 'main', 0)) AS main_0;
+ main_0 
+--------
+   8192
+(1 row)
+
+SELECT page_checksum(get_raw_page('test1', 0), 0) IS NOT NULL AS silly_checksum_test;
+ silly_checksum_test 
+---------------------
+ t
+(1 row)
+
+-- from btree.sql
+SELECT * FROM bt_page_stats('test1_a_idx', 1);
+ blkno | type | live_items | dead_items | avg_item_size | page_size | free_size | btpo_prev | btpo_next | btpo | btpo_flags 
+-------+------+------------+------------+---------------+-----------+-----------+-----------+-----------+------+------------
+     1 | l    |          1 |          0 |            16 |      8192 |      8128 |         0 |         0 |    0 |          3
+(1 row)
+
+SELECT * FROM bt_page_items('test1_a_idx', 1);
+ itemoffset | ctid  | itemlen | nulls | vars |          data           | dead | htid  | tids 
+------------+-------+---------+-------+------+-------------------------+------+-------+------
+          1 | (0,1) |      16 | f     | f    | 01 00 00 00 00 00 00 01 | f    | (0,1) | 
+(1 row)
+
+DROP TABLE test1;
+DROP EXTENSION pageinspect;

contrib/pageinspect/expected/page.out

@@ -32,6 +32,8 @@ SELECT octet_length(get_raw_page('test1', 'vm', 0)) AS vm_0;
 
 SELECT octet_length(get_raw_page('test1', 'vm', 1)) AS vm_1;
 ERROR:  block number 1 is out of range for relation "test1"
+SELECT octet_length(get_raw_page('test1', 'main', -1));
+ERROR:  invalid block number
 SELECT octet_length(get_raw_page('xxx', 'main', 0));
 ERROR:  relation "xxx" does not exist
 SELECT octet_length(get_raw_page('test1', 'xxx', 0));
@@ -55,6 +57,8 @@ SELECT page_checksum(get_raw_page('test1', 0), 0) IS NOT NULL AS silly_checksum_
  t
 (1 row)
 
+SELECT page_checksum(get_raw_page('test1', 0), -1);
+ERROR:  invalid block number
 SELECT tuple_data_split('test1'::regclass, t_data, t_infomask, t_infomask2, t_bits)
     FROM heap_page_items(get_raw_page('test1', 0));
        tuple_data_split