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Remove PageIsValid() and PageSizeIsValid(), which weren't used and seem unnecessary. Some code using these formerly-macros needs some adjustments because it was previously playing loose with the Page vs. PageHeader types, which is no longer possible with the functions instead of macros. Reviewed-by: Amul Sul <sulamul@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/5b558da8-99fb-0a99-83dd-f72f05388517%40enterprisedb.com
377 lines
9.4 KiB
C
377 lines
9.4 KiB
C
/*-------------------------------------------------------------------------
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*
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* rawpage.c
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* Functions to extract a raw page as bytea and inspect it
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*
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* Access-method specific inspection functions are in separate files.
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*
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* Copyright (c) 2007-2022, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/pageinspect/rawpage.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/htup_details.h"
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#include "access/relation.h"
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#include "catalog/namespace.h"
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#include "catalog/pg_type.h"
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#include "funcapi.h"
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#include "miscadmin.h"
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#include "pageinspect.h"
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#include "storage/bufmgr.h"
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#include "storage/checksum.h"
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#include "utils/builtins.h"
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#include "utils/pg_lsn.h"
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#include "utils/rel.h"
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#include "utils/varlena.h"
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PG_MODULE_MAGIC;
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static bytea *get_raw_page_internal(text *relname, ForkNumber forknum,
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BlockNumber blkno);
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/*
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* get_raw_page
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*
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* Returns a copy of a page from shared buffers as a bytea
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*/
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PG_FUNCTION_INFO_V1(get_raw_page_1_9);
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Datum
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get_raw_page_1_9(PG_FUNCTION_ARGS)
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{
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text *relname = PG_GETARG_TEXT_PP(0);
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int64 blkno = PG_GETARG_INT64(1);
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bytea *raw_page;
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if (blkno < 0 || blkno > MaxBlockNumber)
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("invalid block number")));
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raw_page = get_raw_page_internal(relname, MAIN_FORKNUM, blkno);
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PG_RETURN_BYTEA_P(raw_page);
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}
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/*
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* entry point for old extension version
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*/
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PG_FUNCTION_INFO_V1(get_raw_page);
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Datum
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get_raw_page(PG_FUNCTION_ARGS)
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{
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text *relname = PG_GETARG_TEXT_PP(0);
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uint32 blkno = PG_GETARG_UINT32(1);
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bytea *raw_page;
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/*
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* We don't normally bother to check the number of arguments to a C
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* function, but here it's needed for safety because early 8.4 beta
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* releases mistakenly redefined get_raw_page() as taking three arguments.
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*/
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if (PG_NARGS() != 2)
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ereport(ERROR,
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(errmsg("wrong number of arguments to get_raw_page()"),
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errhint("Run the updated pageinspect.sql script.")));
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raw_page = get_raw_page_internal(relname, MAIN_FORKNUM, blkno);
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PG_RETURN_BYTEA_P(raw_page);
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}
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/*
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* get_raw_page_fork
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*
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* Same, for any fork
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*/
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PG_FUNCTION_INFO_V1(get_raw_page_fork_1_9);
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Datum
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get_raw_page_fork_1_9(PG_FUNCTION_ARGS)
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{
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text *relname = PG_GETARG_TEXT_PP(0);
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text *forkname = PG_GETARG_TEXT_PP(1);
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int64 blkno = PG_GETARG_INT64(2);
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bytea *raw_page;
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ForkNumber forknum;
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forknum = forkname_to_number(text_to_cstring(forkname));
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if (blkno < 0 || blkno > MaxBlockNumber)
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("invalid block number")));
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raw_page = get_raw_page_internal(relname, forknum, blkno);
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PG_RETURN_BYTEA_P(raw_page);
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}
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/*
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* Entry point for old extension version
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*/
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PG_FUNCTION_INFO_V1(get_raw_page_fork);
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Datum
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get_raw_page_fork(PG_FUNCTION_ARGS)
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{
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text *relname = PG_GETARG_TEXT_PP(0);
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text *forkname = PG_GETARG_TEXT_PP(1);
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uint32 blkno = PG_GETARG_UINT32(2);
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bytea *raw_page;
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ForkNumber forknum;
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forknum = forkname_to_number(text_to_cstring(forkname));
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raw_page = get_raw_page_internal(relname, forknum, blkno);
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PG_RETURN_BYTEA_P(raw_page);
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}
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/*
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* workhorse
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*/
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static bytea *
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get_raw_page_internal(text *relname, ForkNumber forknum, BlockNumber blkno)
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{
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bytea *raw_page;
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RangeVar *relrv;
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Relation rel;
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char *raw_page_data;
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Buffer buf;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("must be superuser to use raw page functions")));
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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rel = relation_openrv(relrv, AccessShareLock);
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if (!RELKIND_HAS_STORAGE(rel->rd_rel->relkind))
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ereport(ERROR,
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(errcode(ERRCODE_WRONG_OBJECT_TYPE),
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errmsg("cannot get raw page from relation \"%s\"",
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RelationGetRelationName(rel)),
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errdetail_relkind_not_supported(rel->rd_rel->relkind)));
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/*
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* Reject attempts to read non-local temporary relations; we would be
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* likely to get wrong data since we have no visibility into the owning
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* session's local buffers.
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*/
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if (RELATION_IS_OTHER_TEMP(rel))
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("cannot access temporary tables of other sessions")));
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if (blkno >= RelationGetNumberOfBlocksInFork(rel, forknum))
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("block number %u is out of range for relation \"%s\"",
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blkno, RelationGetRelationName(rel))));
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/* Initialize buffer to copy to */
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raw_page = (bytea *) palloc(BLCKSZ + VARHDRSZ);
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SET_VARSIZE(raw_page, BLCKSZ + VARHDRSZ);
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raw_page_data = VARDATA(raw_page);
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/* Take a verbatim copy of the page */
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buf = ReadBufferExtended(rel, forknum, blkno, RBM_NORMAL, NULL);
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LockBuffer(buf, BUFFER_LOCK_SHARE);
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memcpy(raw_page_data, BufferGetPage(buf), BLCKSZ);
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LockBuffer(buf, BUFFER_LOCK_UNLOCK);
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ReleaseBuffer(buf);
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relation_close(rel, AccessShareLock);
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return raw_page;
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}
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/*
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* get_page_from_raw
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*
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* Get a palloc'd, maxalign'ed page image from the result of get_raw_page()
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*
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* On machines with MAXALIGN = 8, the payload of a bytea is not maxaligned,
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* since it will start 4 bytes into a palloc'd value. On alignment-picky
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* machines, this will cause failures in accesses to 8-byte-wide values
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* within the page. We don't need to worry if accessing only 4-byte or
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* smaller fields, but when examining a struct that contains 8-byte fields,
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* use this function for safety.
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*/
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Page
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get_page_from_raw(bytea *raw_page)
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{
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Page page;
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int raw_page_size;
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raw_page_size = VARSIZE_ANY_EXHDR(raw_page);
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if (raw_page_size != BLCKSZ)
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("invalid page size"),
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errdetail("Expected %d bytes, got %d.",
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BLCKSZ, raw_page_size)));
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page = palloc(raw_page_size);
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memcpy(page, VARDATA_ANY(raw_page), raw_page_size);
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return page;
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}
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/*
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* page_header
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*
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* Allows inspection of page header fields of a raw page
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*/
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PG_FUNCTION_INFO_V1(page_header);
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Datum
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page_header(PG_FUNCTION_ARGS)
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{
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bytea *raw_page = PG_GETARG_BYTEA_P(0);
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TupleDesc tupdesc;
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Datum result;
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HeapTuple tuple;
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Datum values[9];
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bool nulls[9];
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Page page;
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PageHeader pageheader;
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XLogRecPtr lsn;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("must be superuser to use raw page functions")));
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page = get_page_from_raw(raw_page);
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pageheader = (PageHeader) page;
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/* Build a tuple descriptor for our result type */
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if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
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elog(ERROR, "return type must be a row type");
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/* Extract information from the page header */
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lsn = PageGetLSN(page);
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/* pageinspect >= 1.2 uses pg_lsn instead of text for the LSN field. */
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if (TupleDescAttr(tupdesc, 0)->atttypid == TEXTOID)
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{
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char lsnchar[64];
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snprintf(lsnchar, sizeof(lsnchar), "%X/%X", LSN_FORMAT_ARGS(lsn));
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values[0] = CStringGetTextDatum(lsnchar);
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}
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else
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values[0] = LSNGetDatum(lsn);
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values[1] = UInt16GetDatum(pageheader->pd_checksum);
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values[2] = UInt16GetDatum(pageheader->pd_flags);
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/* pageinspect >= 1.10 uses int4 instead of int2 for those fields */
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switch (TupleDescAttr(tupdesc, 3)->atttypid)
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{
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case INT2OID:
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Assert(TupleDescAttr(tupdesc, 4)->atttypid == INT2OID &&
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TupleDescAttr(tupdesc, 5)->atttypid == INT2OID &&
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TupleDescAttr(tupdesc, 6)->atttypid == INT2OID);
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values[3] = UInt16GetDatum(pageheader->pd_lower);
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values[4] = UInt16GetDatum(pageheader->pd_upper);
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values[5] = UInt16GetDatum(pageheader->pd_special);
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values[6] = UInt16GetDatum(PageGetPageSize(page));
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break;
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case INT4OID:
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Assert(TupleDescAttr(tupdesc, 4)->atttypid == INT4OID &&
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TupleDescAttr(tupdesc, 5)->atttypid == INT4OID &&
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TupleDescAttr(tupdesc, 6)->atttypid == INT4OID);
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values[3] = Int32GetDatum(pageheader->pd_lower);
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values[4] = Int32GetDatum(pageheader->pd_upper);
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values[5] = Int32GetDatum(pageheader->pd_special);
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values[6] = Int32GetDatum(PageGetPageSize(page));
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break;
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default:
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elog(ERROR, "incorrect output types");
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break;
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}
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values[7] = UInt16GetDatum(PageGetPageLayoutVersion(page));
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values[8] = TransactionIdGetDatum(pageheader->pd_prune_xid);
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/* Build and return the tuple. */
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memset(nulls, 0, sizeof(nulls));
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tuple = heap_form_tuple(tupdesc, values, nulls);
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result = HeapTupleGetDatum(tuple);
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PG_RETURN_DATUM(result);
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}
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/*
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* page_checksum
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*
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* Compute checksum of a raw page
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*/
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PG_FUNCTION_INFO_V1(page_checksum_1_9);
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PG_FUNCTION_INFO_V1(page_checksum);
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static Datum
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page_checksum_internal(PG_FUNCTION_ARGS, enum pageinspect_version ext_version)
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{
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bytea *raw_page = PG_GETARG_BYTEA_P(0);
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int64 blkno = (ext_version == PAGEINSPECT_V1_8 ? PG_GETARG_UINT32(1) : PG_GETARG_INT64(1));
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Page page;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("must be superuser to use raw page functions")));
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if (blkno < 0 || blkno > MaxBlockNumber)
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("invalid block number")));
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page = get_page_from_raw(raw_page);
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if (PageIsNew(page))
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PG_RETURN_NULL();
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PG_RETURN_INT16(pg_checksum_page((char *) page, blkno));
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}
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Datum
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page_checksum_1_9(PG_FUNCTION_ARGS)
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{
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return page_checksum_internal(fcinfo, PAGEINSPECT_V1_9);
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}
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/*
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* Entry point for old extension version
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*/
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Datum
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page_checksum(PG_FUNCTION_ARGS)
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{
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return page_checksum_internal(fcinfo, PAGEINSPECT_V1_8);
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}
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