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) 2007-2026, 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            8 : PG_FUNCTION_INFO_V1(fsm_page_contents);
      33              : 
      34              : Datum
      35            3 : fsm_page_contents(PG_FUNCTION_ARGS)
      36              : {
      37            3 :     bytea      *raw_page = PG_GETARG_BYTEA_P(0);
      38              :     StringInfoData sinfo;
      39              :     Page        page;
      40              :     FSMPage     fsmpage;
      41              :     int         i;
      42              : 
      43            3 :     if (!superuser())
      44            0 :         ereport(ERROR,
      45              :                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
      46              :                  errmsg("must be superuser to use raw page functions")));
      47              : 
      48            3 :     page = get_page_from_raw(raw_page);
      49              : 
      50            2 :     if (PageIsNew(page))
      51            1 :         PG_RETURN_NULL();
      52              : 
      53            1 :     fsmpage = (FSMPage) PageGetContents(page);
      54              : 
      55            1 :     initStringInfo(&sinfo);
      56              : 
      57         8165 :     for (i = 0; i < NodesPerPage; i++)
      58              :     {
      59         8164 :         if (fsmpage->fp_nodes[i] != 0)
      60           13 :             appendStringInfo(&sinfo, "%d: %d\n", i, fsmpage->fp_nodes[i]);
      61              :     }
      62            1 :     appendStringInfo(&sinfo, "fp_next_slot: %d\n", fsmpage->fp_next_slot);
      63              : 
      64            1 :     PG_RETURN_TEXT_P(cstring_to_text_with_len(sinfo.data, sinfo.len));
      65              : }