Line data    Source code

       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * fsmfuncs.c
       4             :  *    Functions to investigate FSM pages
       5             :  *
       6             :  * These functions are restricted to superusers for the fear of introducing
       7             :  * security holes if the input checking isn't as water-tight as it should.
       8             :  * You'd need to be superuser to obtain a raw page image anyway, so
       9             :  * there's hardly any use case for using these without superuser-rights
      10             :  * anyway.
      11             :  *
      12             :  * Copyright (c) 2007-2024, PostgreSQL Global Development Group
      13             :  *
      14             :  * IDENTIFICATION
      15             :  *    contrib/pageinspect/fsmfuncs.c
      16             :  *
      17             :  *-------------------------------------------------------------------------
      18             :  */
      19             : 
      20             : #include "postgres.h"
      21             : 
      22             : #include "fmgr.h"
      23             : #include "lib/stringinfo.h"
      24             : #include "miscadmin.h"
      25             : #include "pageinspect.h"
      26             : #include "storage/fsm_internals.h"
      27             : #include "utils/builtins.h"
      28             : 
      29             : /*
      30             :  * Dumps the contents of a FSM page.
      31             :  */
      32          14 : PG_FUNCTION_INFO_V1(fsm_page_contents);
      33             : 
      34             : Datum
      35           6 : fsm_page_contents(PG_FUNCTION_ARGS)
      36             : {
      37           6 :     bytea      *raw_page = PG_GETARG_BYTEA_P(0);
      38             :     StringInfoData sinfo;
      39             :     Page        page;
      40             :     FSMPage     fsmpage;
      41             :     int         i;
      42             : 
      43           6 :     if (!superuser())
      44           0 :         ereport(ERROR,
      45             :                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
      46             :                  errmsg("must be superuser to use raw page functions")));
      47             : 
      48           6 :     page = get_page_from_raw(raw_page);
      49             : 
      50           4 :     if (PageIsNew(page))
      51           2 :         PG_RETURN_NULL();
      52             : 
      53           2 :     fsmpage = (FSMPage) PageGetContents(page);
      54             : 
      55           2 :     initStringInfo(&sinfo);
      56             : 
      57       16330 :     for (i = 0; i < NodesPerPage; i++)
      58             :     {
      59       16328 :         if (fsmpage->fp_nodes[i] != 0)
      60          26 :             appendStringInfo(&sinfo, "%d: %d\n", i, fsmpage->fp_nodes[i]);
      61             :     }
      62           2 :     appendStringInfo(&sinfo, "fp_next_slot: %d\n", fsmpage->fp_next_slot);
      63             : 
      64           2 :     PG_RETURN_TEXT_P(cstring_to_text_with_len(sinfo.data, sinfo.len));
      65             : }