rawpage.c File Reference

#include "postgres.h"
#include "access/htup_details.h"
#include "access/relation.h"
#include "catalog/namespace.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "pageinspect.h"
#include "storage/bufmgr.h"
#include "storage/checksum.h"
#include "utils/builtins.h"
#include "utils/pg_lsn.h"
#include "utils/rel.h"
#include "utils/varlena.h"

Include dependency graph for rawpage.c:

Go to the source code of this file.

Functions
static bytea *	get_raw_page_internal (text *relname, ForkNumber forknum, BlockNumber blkno)
	PG_FUNCTION_INFO_V1 (get_raw_page)
Datum	get_raw_page (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (get_raw_page_fork)
Datum	get_raw_page_fork (PG_FUNCTION_ARGS)
Page	get_page_from_raw (bytea *raw_page)
	PG_FUNCTION_INFO_V1 (page_header)
Datum	page_header (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (page_checksum)
Datum	page_checksum (PG_FUNCTION_ARGS)

Variables
	PG_MODULE_MAGIC

Function Documentation

get_page_from_raw()

Page get_page_from_raw

(

bytea *

raw_page

)

Definition at line 187 of file rawpage.c.

References ereport, errcode(), errdetail(), errmsg(), ERROR, page_header(), palloc(), PG_FUNCTION_INFO_V1(), VARDATA_ANY, and VARSIZE_ANY_EXHDR.

Referenced by gin_leafpage_items(), gin_metapage_info(), gin_page_opaque_info(), and verify_hash_page().

{
    Page        page;
    int         raw_page_size;

    raw_page_size = VARSIZE_ANY_EXHDR(raw_page);

    if (raw_page_size != BLCKSZ)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("invalid page size"),
                 errdetail("Expected %d bytes, got %d.",
                           BLCKSZ, raw_page_size)));

    page = palloc(raw_page_size);

    memcpy(page, VARDATA_ANY(raw_page), raw_page_size);

    return page;
}

get_raw_page()

Datum get_raw_page

(

PG_FUNCTION_ARGS

)

Definition at line 46 of file rawpage.c.

References ereport, errhint(), errmsg(), ERROR, get_raw_page_fork(), get_raw_page_internal(), MAIN_FORKNUM, PG_FUNCTION_INFO_V1(), PG_GETARG_TEXT_PP, PG_GETARG_UINT32, PG_NARGS, PG_RETURN_BYTEA_P, and relname.

{
    text       *relname = PG_GETARG_TEXT_PP(0);
    uint32      blkno = PG_GETARG_UINT32(1);
    bytea      *raw_page;

    /*
     * We don't normally bother to check the number of arguments to a C
     * function, but here it's needed for safety because early 8.4 beta
     * releases mistakenly redefined get_raw_page() as taking three arguments.
     */
    if (PG_NARGS() != 2)
        ereport(ERROR,
                (errmsg("wrong number of arguments to get_raw_page()"),
                 errhint("Run the updated pageinspect.sql script.")));

    raw_page = get_raw_page_internal(relname, MAIN_FORKNUM, blkno);

    PG_RETURN_BYTEA_P(raw_page);
}

get_raw_page_fork()

Datum get_raw_page_fork

(

PG_FUNCTION_ARGS

)

Definition at line 75 of file rawpage.c.

References forkname_to_number(), get_raw_page_internal(), PG_GETARG_TEXT_PP, PG_GETARG_UINT32, PG_RETURN_BYTEA_P, relname, and text_to_cstring().

Referenced by get_raw_page().

{
    text       *relname = PG_GETARG_TEXT_PP(0);
    text       *forkname = PG_GETARG_TEXT_PP(1);
    uint32      blkno = PG_GETARG_UINT32(2);
    bytea      *raw_page;
    ForkNumber  forknum;

    forknum = forkname_to_number(text_to_cstring(forkname));

    raw_page = get_raw_page_internal(relname, forknum, blkno);

    PG_RETURN_BYTEA_P(raw_page);
}

get_raw_page_internal()

static bytea * get_raw_page_internal ( text *  relname, ForkNumber  forknum, BlockNumber  blkno  )

static

Definition at line 94 of file rawpage.c.

References AccessShareLock, buf, BUFFER_LOCK_SHARE, BUFFER_LOCK_UNLOCK, BufferGetPage, ereport, errcode(), errmsg(), ERROR, LockBuffer(), makeRangeVarFromNameList(), palloc(), RBM_NORMAL, RelationData::rd_rel, ReadBufferExtended(), relation_close(), RELATION_IS_OTHER_TEMP, relation_openrv(), RelationGetNumberOfBlocksInFork(), RelationGetRelationName, ReleaseBuffer(), SET_VARSIZE, superuser(), textToQualifiedNameList(), VARDATA, and VARHDRSZ.

Referenced by get_raw_page(), and get_raw_page_fork().

{
    bytea      *raw_page;
    RangeVar   *relrv;
    Relation    rel;
    char       *raw_page_data;
    Buffer      buf;

    if (!superuser())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("must be superuser to use raw page functions")));

    relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
    rel = relation_openrv(relrv, AccessShareLock);

    /* Check that this relation has storage */
    if (rel->rd_rel->relkind == RELKIND_VIEW)
        ereport(ERROR,
                (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                 errmsg("cannot get raw page from view \"%s\"",
                        RelationGetRelationName(rel))));
    if (rel->rd_rel->relkind == RELKIND_COMPOSITE_TYPE)
        ereport(ERROR,
                (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                 errmsg("cannot get raw page from composite type \"%s\"",
                        RelationGetRelationName(rel))));
    if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
        ereport(ERROR,
                (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                 errmsg("cannot get raw page from foreign table \"%s\"",
                        RelationGetRelationName(rel))));
    if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
        ereport(ERROR,
                (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                 errmsg("cannot get raw page from partitioned table \"%s\"",
                        RelationGetRelationName(rel))));
    if (rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
        ereport(ERROR,
                (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                 errmsg("cannot get raw page from partitioned index \"%s\"",
                        RelationGetRelationName(rel))));

    /*
     * Reject attempts to read non-local temporary relations; we would be
     * likely to get wrong data since we have no visibility into the owning
     * session's local buffers.
     */
    if (RELATION_IS_OTHER_TEMP(rel))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("cannot access temporary tables of other sessions")));

    if (blkno >= RelationGetNumberOfBlocksInFork(rel, forknum))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("block number %u is out of range for relation \"%s\"",
                        blkno, RelationGetRelationName(rel))));

    /* Initialize buffer to copy to */
    raw_page = (bytea *) palloc(BLCKSZ + VARHDRSZ);
    SET_VARSIZE(raw_page, BLCKSZ + VARHDRSZ);
    raw_page_data = VARDATA(raw_page);

    /* Take a verbatim copy of the page */

    buf = ReadBufferExtended(rel, forknum, blkno, RBM_NORMAL, NULL);
    LockBuffer(buf, BUFFER_LOCK_SHARE);

    memcpy(raw_page_data, BufferGetPage(buf), BLCKSZ);

    LockBuffer(buf, BUFFER_LOCK_UNLOCK);
    ReleaseBuffer(buf);

    relation_close(rel, AccessShareLock);

    return raw_page;
}

page_checksum()

Datum page_checksum

(

PG_FUNCTION_ARGS

)

Definition at line 298 of file rawpage.c.

References ereport, errcode(), errmsg(), ERROR, pg_checksum_page(), PG_GETARG_BYTEA_P, PG_GETARG_INT32, PG_RETURN_INT16, superuser(), VARDATA, VARHDRSZ, and VARSIZE.

Referenced by page_header().

{
    bytea      *raw_page = PG_GETARG_BYTEA_P(0);
    uint32      blkno = PG_GETARG_INT32(1);
    int         raw_page_size;
    PageHeader  page;

    if (!superuser())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("must be superuser to use raw page functions")));

    raw_page_size = VARSIZE(raw_page) - VARHDRSZ;

    /*
     * Check that the supplied page is of the right size.
     */
    if (raw_page_size != BLCKSZ)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("incorrect size of input page (%d bytes)", raw_page_size)));

    page = (PageHeader) VARDATA(raw_page);

    PG_RETURN_INT16(pg_checksum_page((char *) page, blkno));
}

page_header()

Datum page_header

(

PG_FUNCTION_ARGS

)

Definition at line 218 of file rawpage.c.

References atttypid, CStringGetTextDatum, elog, ereport, errcode(), errmsg(), ERROR, get_call_result_type(), heap_form_tuple(), HeapTupleGetDatum, LSNGetDatum, page_checksum(), PageGetLSN, PageGetPageLayoutVersion, PageGetPageSize, PageHeaderData::pd_checksum, PageHeaderData::pd_flags, PageHeaderData::pd_lower, PageHeaderData::pd_prune_xid, PageHeaderData::pd_special, PageHeaderData::pd_upper, PG_FUNCTION_INFO_V1(), PG_GETARG_BYTEA_P, PG_RETURN_DATUM, SizeOfPageHeaderData, snprintf, superuser(), TransactionIdGetDatum, TupleDescAttr, TYPEFUNC_COMPOSITE, UInt16GetDatum, values, VARDATA, VARHDRSZ, and VARSIZE.

Referenced by get_page_from_raw().

{
    bytea      *raw_page = PG_GETARG_BYTEA_P(0);
    int         raw_page_size;

    TupleDesc   tupdesc;

    Datum       result;
    HeapTuple   tuple;
    Datum       values[9];
    bool        nulls[9];

    PageHeader  page;
    XLogRecPtr  lsn;

    if (!superuser())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("must be superuser to use raw page functions")));

    raw_page_size = VARSIZE(raw_page) - VARHDRSZ;

    /*
     * Check that enough data was supplied, so that we don't try to access
     * fields outside the supplied buffer.
     */
    if (raw_page_size < SizeOfPageHeaderData)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("input page too small (%d bytes)", raw_page_size)));

    page = (PageHeader) VARDATA(raw_page);

    /* Build a tuple descriptor for our result type */
    if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");

    /* Extract information from the page header */

    lsn = PageGetLSN(page);

    /* pageinspect >= 1.2 uses pg_lsn instead of text for the LSN field. */
    if (TupleDescAttr(tupdesc, 0)->atttypid == TEXTOID)
    {
        char        lsnchar[64];

        snprintf(lsnchar, sizeof(lsnchar), "%X/%X",
                 (uint32) (lsn >> 32), (uint32) lsn);
        values[0] = CStringGetTextDatum(lsnchar);
    }
    else
        values[0] = LSNGetDatum(lsn);
    values[1] = UInt16GetDatum(page->pd_checksum);
    values[2] = UInt16GetDatum(page->pd_flags);
    values[3] = UInt16GetDatum(page->pd_lower);
    values[4] = UInt16GetDatum(page->pd_upper);
    values[5] = UInt16GetDatum(page->pd_special);
    values[6] = UInt16GetDatum(PageGetPageSize(page));
    values[7] = UInt16GetDatum(PageGetPageLayoutVersion(page));
    values[8] = TransactionIdGetDatum(page->pd_prune_xid);

    /* Build and return the tuple. */

    memset(nulls, 0, sizeof(nulls));

    tuple = heap_form_tuple(tupdesc, values, nulls);
    result = HeapTupleGetDatum(tuple);

    PG_RETURN_DATUM(result);
}

PG_FUNCTION_INFO_V1() [1/4]

PG_FUNCTION_INFO_V1

(

get_raw_page

)

Referenced by get_page_from_raw(), get_raw_page(), and page_header().

PG_FUNCTION_INFO_V1() [2/4]

PG_FUNCTION_INFO_V1

(

get_raw_page_fork

)

PG_FUNCTION_INFO_V1() [3/4]

PG_FUNCTION_INFO_V1

(

page_header

)

PG_FUNCTION_INFO_V1() [4/4]

PG_FUNCTION_INFO_V1

(

page_checksum

)

Variable Documentation

PG_MODULE_MAGIC

PG_MODULE_MAGIC

Definition at line 32 of file rawpage.c.