postgresql/contrib/pageinspect/fsmfuncs.c

66 lines
1.6 KiB
C

/*-------------------------------------------------------------------------
*
* fsmfuncs.c
* Functions to investigate FSM pages
*
* These functions are restricted to superusers for the fear of introducing
* security holes if the input checking isn't as water-tight as it should.
* You'd need to be superuser to obtain a raw page image anyway, so
* there's hardly any use case for using these without superuser-rights
* anyway.
*
* Copyright (c) 2007-2022, PostgreSQL Global Development Group
*
* IDENTIFICATION
* contrib/pageinspect/fsmfuncs.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "funcapi.h"
#include "lib/stringinfo.h"
#include "miscadmin.h"
#include "pageinspect.h"
#include "storage/fsm_internals.h"
#include "utils/builtins.h"
/*
* Dumps the contents of a FSM page.
*/
PG_FUNCTION_INFO_V1(fsm_page_contents);
Datum
fsm_page_contents(PG_FUNCTION_ARGS)
{
bytea *raw_page = PG_GETARG_BYTEA_P(0);
StringInfoData sinfo;
Page page;
FSMPage fsmpage;
int i;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to use raw page functions")));
page = get_page_from_raw(raw_page);
if (PageIsNew(page))
PG_RETURN_NULL();
fsmpage = (FSMPage) PageGetContents(page);
initStringInfo(&sinfo);
for (i = 0; i < NodesPerPage; i++)
{
if (fsmpage->fp_nodes[i] != 0)
appendStringInfo(&sinfo, "%d: %d\n", i, fsmpage->fp_nodes[i]);
}
appendStringInfo(&sinfo, "fp_next_slot: %d\n", fsmpage->fp_next_slot);
PG_RETURN_TEXT_P(cstring_to_text_with_len(sinfo.data, sinfo.len));
}